1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Performance events core code:
4  *
5  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6  *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7  *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8  *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9  */
10 
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
57 
58 #include "internal.h"
59 
60 #include <asm/irq_regs.h>
61 
62 typedef int (*remote_function_f)(void *);
63 
64 struct remote_function_call {
65 	struct task_struct	*p;
66 	remote_function_f	func;
67 	void			*info;
68 	int			ret;
69 };
70 
remote_function(void * data)71 static void remote_function(void *data)
72 {
73 	struct remote_function_call *tfc = data;
74 	struct task_struct *p = tfc->p;
75 
76 	if (p) {
77 		/* -EAGAIN */
78 		if (task_cpu(p) != smp_processor_id())
79 			return;
80 
81 		/*
82 		 * Now that we're on right CPU with IRQs disabled, we can test
83 		 * if we hit the right task without races.
84 		 */
85 
86 		tfc->ret = -ESRCH; /* No such (running) process */
87 		if (p != current)
88 			return;
89 	}
90 
91 	tfc->ret = tfc->func(tfc->info);
92 }
93 
94 /**
95  * task_function_call - call a function on the cpu on which a task runs
96  * @p:		the task to evaluate
97  * @func:	the function to be called
98  * @info:	the function call argument
99  *
100  * Calls the function @func when the task is currently running. This might
101  * be on the current CPU, which just calls the function directly.  This will
102  * retry due to any failures in smp_call_function_single(), such as if the
103  * task_cpu() goes offline concurrently.
104  *
105  * returns @func return value or -ESRCH or -ENXIO when the process isn't running
106  */
107 static int
task_function_call(struct task_struct * p,remote_function_f func,void * info)108 task_function_call(struct task_struct *p, remote_function_f func, void *info)
109 {
110 	struct remote_function_call data = {
111 		.p	= p,
112 		.func	= func,
113 		.info	= info,
114 		.ret	= -EAGAIN,
115 	};
116 	int ret;
117 
118 	for (;;) {
119 		ret = smp_call_function_single(task_cpu(p), remote_function,
120 					       &data, 1);
121 		if (!ret)
122 			ret = data.ret;
123 
124 		if (ret != -EAGAIN)
125 			break;
126 
127 		cond_resched();
128 	}
129 
130 	return ret;
131 }
132 
133 /**
134  * cpu_function_call - call a function on the cpu
135  * @cpu:	target cpu to queue this function
136  * @func:	the function to be called
137  * @info:	the function call argument
138  *
139  * Calls the function @func on the remote cpu.
140  *
141  * returns: @func return value or -ENXIO when the cpu is offline
142  */
cpu_function_call(int cpu,remote_function_f func,void * info)143 static int cpu_function_call(int cpu, remote_function_f func, void *info)
144 {
145 	struct remote_function_call data = {
146 		.p	= NULL,
147 		.func	= func,
148 		.info	= info,
149 		.ret	= -ENXIO, /* No such CPU */
150 	};
151 
152 	smp_call_function_single(cpu, remote_function, &data, 1);
153 
154 	return data.ret;
155 }
156 
157 static inline struct perf_cpu_context *
__get_cpu_context(struct perf_event_context * ctx)158 __get_cpu_context(struct perf_event_context *ctx)
159 {
160 	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
161 }
162 
perf_ctx_lock(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)163 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
164 			  struct perf_event_context *ctx)
165 {
166 	raw_spin_lock(&cpuctx->ctx.lock);
167 	if (ctx)
168 		raw_spin_lock(&ctx->lock);
169 }
170 
perf_ctx_unlock(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)171 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
172 			    struct perf_event_context *ctx)
173 {
174 	if (ctx)
175 		raw_spin_unlock(&ctx->lock);
176 	raw_spin_unlock(&cpuctx->ctx.lock);
177 }
178 
179 #define TASK_TOMBSTONE ((void *)-1L)
180 
is_kernel_event(struct perf_event * event)181 static bool is_kernel_event(struct perf_event *event)
182 {
183 	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
184 }
185 
186 /*
187  * On task ctx scheduling...
188  *
189  * When !ctx->nr_events a task context will not be scheduled. This means
190  * we can disable the scheduler hooks (for performance) without leaving
191  * pending task ctx state.
192  *
193  * This however results in two special cases:
194  *
195  *  - removing the last event from a task ctx; this is relatively straight
196  *    forward and is done in __perf_remove_from_context.
197  *
198  *  - adding the first event to a task ctx; this is tricky because we cannot
199  *    rely on ctx->is_active and therefore cannot use event_function_call().
200  *    See perf_install_in_context().
201  *
202  * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
203  */
204 
205 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
206 			struct perf_event_context *, void *);
207 
208 struct event_function_struct {
209 	struct perf_event *event;
210 	event_f func;
211 	void *data;
212 };
213 
event_function(void * info)214 static int event_function(void *info)
215 {
216 	struct event_function_struct *efs = info;
217 	struct perf_event *event = efs->event;
218 	struct perf_event_context *ctx = event->ctx;
219 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
220 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
221 	int ret = 0;
222 
223 	lockdep_assert_irqs_disabled();
224 
225 	perf_ctx_lock(cpuctx, task_ctx);
226 	/*
227 	 * Since we do the IPI call without holding ctx->lock things can have
228 	 * changed, double check we hit the task we set out to hit.
229 	 */
230 	if (ctx->task) {
231 		if (ctx->task != current) {
232 			ret = -ESRCH;
233 			goto unlock;
234 		}
235 
236 		/*
237 		 * We only use event_function_call() on established contexts,
238 		 * and event_function() is only ever called when active (or
239 		 * rather, we'll have bailed in task_function_call() or the
240 		 * above ctx->task != current test), therefore we must have
241 		 * ctx->is_active here.
242 		 */
243 		WARN_ON_ONCE(!ctx->is_active);
244 		/*
245 		 * And since we have ctx->is_active, cpuctx->task_ctx must
246 		 * match.
247 		 */
248 		WARN_ON_ONCE(task_ctx != ctx);
249 	} else {
250 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
251 	}
252 
253 	efs->func(event, cpuctx, ctx, efs->data);
254 unlock:
255 	perf_ctx_unlock(cpuctx, task_ctx);
256 
257 	return ret;
258 }
259 
event_function_call(struct perf_event * event,event_f func,void * data)260 static void event_function_call(struct perf_event *event, event_f func, void *data)
261 {
262 	struct perf_event_context *ctx = event->ctx;
263 	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
264 	struct event_function_struct efs = {
265 		.event = event,
266 		.func = func,
267 		.data = data,
268 	};
269 
270 	if (!event->parent) {
271 		/*
272 		 * If this is a !child event, we must hold ctx::mutex to
273 		 * stabilize the event->ctx relation. See
274 		 * perf_event_ctx_lock().
275 		 */
276 		lockdep_assert_held(&ctx->mutex);
277 	}
278 
279 	if (!task) {
280 		cpu_function_call(event->cpu, event_function, &efs);
281 		return;
282 	}
283 
284 	if (task == TASK_TOMBSTONE)
285 		return;
286 
287 again:
288 	if (!task_function_call(task, event_function, &efs))
289 		return;
290 
291 	raw_spin_lock_irq(&ctx->lock);
292 	/*
293 	 * Reload the task pointer, it might have been changed by
294 	 * a concurrent perf_event_context_sched_out().
295 	 */
296 	task = ctx->task;
297 	if (task == TASK_TOMBSTONE) {
298 		raw_spin_unlock_irq(&ctx->lock);
299 		return;
300 	}
301 	if (ctx->is_active) {
302 		raw_spin_unlock_irq(&ctx->lock);
303 		goto again;
304 	}
305 	func(event, NULL, ctx, data);
306 	raw_spin_unlock_irq(&ctx->lock);
307 }
308 
309 /*
310  * Similar to event_function_call() + event_function(), but hard assumes IRQs
311  * are already disabled and we're on the right CPU.
312  */
event_function_local(struct perf_event * event,event_f func,void * data)313 static void event_function_local(struct perf_event *event, event_f func, void *data)
314 {
315 	struct perf_event_context *ctx = event->ctx;
316 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
317 	struct task_struct *task = READ_ONCE(ctx->task);
318 	struct perf_event_context *task_ctx = NULL;
319 
320 	lockdep_assert_irqs_disabled();
321 
322 	if (task) {
323 		if (task == TASK_TOMBSTONE)
324 			return;
325 
326 		task_ctx = ctx;
327 	}
328 
329 	perf_ctx_lock(cpuctx, task_ctx);
330 
331 	task = ctx->task;
332 	if (task == TASK_TOMBSTONE)
333 		goto unlock;
334 
335 	if (task) {
336 		/*
337 		 * We must be either inactive or active and the right task,
338 		 * otherwise we're screwed, since we cannot IPI to somewhere
339 		 * else.
340 		 */
341 		if (ctx->is_active) {
342 			if (WARN_ON_ONCE(task != current))
343 				goto unlock;
344 
345 			if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
346 				goto unlock;
347 		}
348 	} else {
349 		WARN_ON_ONCE(&cpuctx->ctx != ctx);
350 	}
351 
352 	func(event, cpuctx, ctx, data);
353 unlock:
354 	perf_ctx_unlock(cpuctx, task_ctx);
355 }
356 
357 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
358 		       PERF_FLAG_FD_OUTPUT  |\
359 		       PERF_FLAG_PID_CGROUP |\
360 		       PERF_FLAG_FD_CLOEXEC)
361 
362 /*
363  * branch priv levels that need permission checks
364  */
365 #define PERF_SAMPLE_BRANCH_PERM_PLM \
366 	(PERF_SAMPLE_BRANCH_KERNEL |\
367 	 PERF_SAMPLE_BRANCH_HV)
368 
369 enum event_type_t {
370 	EVENT_FLEXIBLE = 0x1,
371 	EVENT_PINNED = 0x2,
372 	EVENT_TIME = 0x4,
373 	/* see ctx_resched() for details */
374 	EVENT_CPU = 0x8,
375 	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
376 };
377 
378 /*
379  * perf_sched_events : >0 events exist
380  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
381  */
382 
383 static void perf_sched_delayed(struct work_struct *work);
384 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
385 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
386 static DEFINE_MUTEX(perf_sched_mutex);
387 static atomic_t perf_sched_count;
388 
389 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
390 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
392 
393 static atomic_t nr_mmap_events __read_mostly;
394 static atomic_t nr_comm_events __read_mostly;
395 static atomic_t nr_namespaces_events __read_mostly;
396 static atomic_t nr_task_events __read_mostly;
397 static atomic_t nr_freq_events __read_mostly;
398 static atomic_t nr_switch_events __read_mostly;
399 static atomic_t nr_ksymbol_events __read_mostly;
400 static atomic_t nr_bpf_events __read_mostly;
401 static atomic_t nr_cgroup_events __read_mostly;
402 static atomic_t nr_text_poke_events __read_mostly;
403 static atomic_t nr_build_id_events __read_mostly;
404 
405 static LIST_HEAD(pmus);
406 static DEFINE_MUTEX(pmus_lock);
407 static struct srcu_struct pmus_srcu;
408 static cpumask_var_t perf_online_mask;
409 static struct kmem_cache *perf_event_cache;
410 
411 /*
412  * perf event paranoia level:
413  *  -1 - not paranoid at all
414  *   0 - disallow raw tracepoint access for unpriv
415  *   1 - disallow cpu events for unpriv
416  *   2 - disallow kernel profiling for unpriv
417  */
418 int sysctl_perf_event_paranoid __read_mostly = 2;
419 
420 /* Minimum for 512 kiB + 1 user control page */
421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
422 
423 /*
424  * max perf event sample rate
425  */
426 #define DEFAULT_MAX_SAMPLE_RATE		100000
427 #define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
428 #define DEFAULT_CPU_TIME_MAX_PERCENT	25
429 
430 int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
431 
432 static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
433 static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
434 
435 static int perf_sample_allowed_ns __read_mostly =
436 	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
437 
update_perf_cpu_limits(void)438 static void update_perf_cpu_limits(void)
439 {
440 	u64 tmp = perf_sample_period_ns;
441 
442 	tmp *= sysctl_perf_cpu_time_max_percent;
443 	tmp = div_u64(tmp, 100);
444 	if (!tmp)
445 		tmp = 1;
446 
447 	WRITE_ONCE(perf_sample_allowed_ns, tmp);
448 }
449 
450 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
451 
perf_proc_update_handler(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)452 int perf_proc_update_handler(struct ctl_table *table, int write,
453 		void *buffer, size_t *lenp, loff_t *ppos)
454 {
455 	int ret;
456 	int perf_cpu = sysctl_perf_cpu_time_max_percent;
457 	/*
458 	 * If throttling is disabled don't allow the write:
459 	 */
460 	if (write && (perf_cpu == 100 || perf_cpu == 0))
461 		return -EINVAL;
462 
463 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
464 	if (ret || !write)
465 		return ret;
466 
467 	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
468 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 	update_perf_cpu_limits();
470 
471 	return 0;
472 }
473 
474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
475 
perf_cpu_time_max_percent_handler(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
477 		void *buffer, size_t *lenp, loff_t *ppos)
478 {
479 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
480 
481 	if (ret || !write)
482 		return ret;
483 
484 	if (sysctl_perf_cpu_time_max_percent == 100 ||
485 	    sysctl_perf_cpu_time_max_percent == 0) {
486 		printk(KERN_WARNING
487 		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
488 		WRITE_ONCE(perf_sample_allowed_ns, 0);
489 	} else {
490 		update_perf_cpu_limits();
491 	}
492 
493 	return 0;
494 }
495 
496 /*
497  * perf samples are done in some very critical code paths (NMIs).
498  * If they take too much CPU time, the system can lock up and not
499  * get any real work done.  This will drop the sample rate when
500  * we detect that events are taking too long.
501  */
502 #define NR_ACCUMULATED_SAMPLES 128
503 static DEFINE_PER_CPU(u64, running_sample_length);
504 
505 static u64 __report_avg;
506 static u64 __report_allowed;
507 
perf_duration_warn(struct irq_work * w)508 static void perf_duration_warn(struct irq_work *w)
509 {
510 	printk_ratelimited(KERN_INFO
511 		"perf: interrupt took too long (%lld > %lld), lowering "
512 		"kernel.perf_event_max_sample_rate to %d\n",
513 		__report_avg, __report_allowed,
514 		sysctl_perf_event_sample_rate);
515 }
516 
517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
518 
perf_sample_event_took(u64 sample_len_ns)519 void perf_sample_event_took(u64 sample_len_ns)
520 {
521 	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
522 	u64 running_len;
523 	u64 avg_len;
524 	u32 max;
525 
526 	if (max_len == 0)
527 		return;
528 
529 	/* Decay the counter by 1 average sample. */
530 	running_len = __this_cpu_read(running_sample_length);
531 	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
532 	running_len += sample_len_ns;
533 	__this_cpu_write(running_sample_length, running_len);
534 
535 	/*
536 	 * Note: this will be biased artifically low until we have
537 	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
538 	 * from having to maintain a count.
539 	 */
540 	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
541 	if (avg_len <= max_len)
542 		return;
543 
544 	__report_avg = avg_len;
545 	__report_allowed = max_len;
546 
547 	/*
548 	 * Compute a throttle threshold 25% below the current duration.
549 	 */
550 	avg_len += avg_len / 4;
551 	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
552 	if (avg_len < max)
553 		max /= (u32)avg_len;
554 	else
555 		max = 1;
556 
557 	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
558 	WRITE_ONCE(max_samples_per_tick, max);
559 
560 	sysctl_perf_event_sample_rate = max * HZ;
561 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
562 
563 	if (!irq_work_queue(&perf_duration_work)) {
564 		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
565 			     "kernel.perf_event_max_sample_rate to %d\n",
566 			     __report_avg, __report_allowed,
567 			     sysctl_perf_event_sample_rate);
568 	}
569 }
570 
571 static atomic64_t perf_event_id;
572 
573 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
574 			      enum event_type_t event_type);
575 
576 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
577 			     enum event_type_t event_type);
578 
579 static void update_context_time(struct perf_event_context *ctx);
580 static u64 perf_event_time(struct perf_event *event);
581 
perf_event_print_debug(void)582 void __weak perf_event_print_debug(void)	{ }
583 
perf_clock(void)584 static inline u64 perf_clock(void)
585 {
586 	return local_clock();
587 }
588 
perf_event_clock(struct perf_event * event)589 static inline u64 perf_event_clock(struct perf_event *event)
590 {
591 	return event->clock();
592 }
593 
594 /*
595  * State based event timekeeping...
596  *
597  * The basic idea is to use event->state to determine which (if any) time
598  * fields to increment with the current delta. This means we only need to
599  * update timestamps when we change state or when they are explicitly requested
600  * (read).
601  *
602  * Event groups make things a little more complicated, but not terribly so. The
603  * rules for a group are that if the group leader is OFF the entire group is
604  * OFF, irrespecive of what the group member states are. This results in
605  * __perf_effective_state().
606  *
607  * A futher ramification is that when a group leader flips between OFF and
608  * !OFF, we need to update all group member times.
609  *
610  *
611  * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
612  * need to make sure the relevant context time is updated before we try and
613  * update our timestamps.
614  */
615 
616 static __always_inline enum perf_event_state
__perf_effective_state(struct perf_event * event)617 __perf_effective_state(struct perf_event *event)
618 {
619 	struct perf_event *leader = event->group_leader;
620 
621 	if (leader->state <= PERF_EVENT_STATE_OFF)
622 		return leader->state;
623 
624 	return event->state;
625 }
626 
627 static __always_inline void
__perf_update_times(struct perf_event * event,u64 now,u64 * enabled,u64 * running)628 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
629 {
630 	enum perf_event_state state = __perf_effective_state(event);
631 	u64 delta = now - event->tstamp;
632 
633 	*enabled = event->total_time_enabled;
634 	if (state >= PERF_EVENT_STATE_INACTIVE)
635 		*enabled += delta;
636 
637 	*running = event->total_time_running;
638 	if (state >= PERF_EVENT_STATE_ACTIVE)
639 		*running += delta;
640 }
641 
perf_event_update_time(struct perf_event * event)642 static void perf_event_update_time(struct perf_event *event)
643 {
644 	u64 now = perf_event_time(event);
645 
646 	__perf_update_times(event, now, &event->total_time_enabled,
647 					&event->total_time_running);
648 	event->tstamp = now;
649 }
650 
perf_event_update_sibling_time(struct perf_event * leader)651 static void perf_event_update_sibling_time(struct perf_event *leader)
652 {
653 	struct perf_event *sibling;
654 
655 	for_each_sibling_event(sibling, leader)
656 		perf_event_update_time(sibling);
657 }
658 
659 static void
perf_event_set_state(struct perf_event * event,enum perf_event_state state)660 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
661 {
662 	if (event->state == state)
663 		return;
664 
665 	perf_event_update_time(event);
666 	/*
667 	 * If a group leader gets enabled/disabled all its siblings
668 	 * are affected too.
669 	 */
670 	if ((event->state < 0) ^ (state < 0))
671 		perf_event_update_sibling_time(event);
672 
673 	WRITE_ONCE(event->state, state);
674 }
675 
676 /*
677  * UP store-release, load-acquire
678  */
679 
680 #define __store_release(ptr, val)					\
681 do {									\
682 	barrier();							\
683 	WRITE_ONCE(*(ptr), (val));					\
684 } while (0)
685 
686 #define __load_acquire(ptr)						\
687 ({									\
688 	__unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr));	\
689 	barrier();							\
690 	___p;								\
691 })
692 
693 #ifdef CONFIG_CGROUP_PERF
694 
695 static inline bool
perf_cgroup_match(struct perf_event * event)696 perf_cgroup_match(struct perf_event *event)
697 {
698 	struct perf_event_context *ctx = event->ctx;
699 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
700 
701 	/* @event doesn't care about cgroup */
702 	if (!event->cgrp)
703 		return true;
704 
705 	/* wants specific cgroup scope but @cpuctx isn't associated with any */
706 	if (!cpuctx->cgrp)
707 		return false;
708 
709 	/*
710 	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
711 	 * also enabled for all its descendant cgroups.  If @cpuctx's
712 	 * cgroup is a descendant of @event's (the test covers identity
713 	 * case), it's a match.
714 	 */
715 	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
716 				    event->cgrp->css.cgroup);
717 }
718 
perf_detach_cgroup(struct perf_event * event)719 static inline void perf_detach_cgroup(struct perf_event *event)
720 {
721 	css_put(&event->cgrp->css);
722 	event->cgrp = NULL;
723 }
724 
is_cgroup_event(struct perf_event * event)725 static inline int is_cgroup_event(struct perf_event *event)
726 {
727 	return event->cgrp != NULL;
728 }
729 
perf_cgroup_event_time(struct perf_event * event)730 static inline u64 perf_cgroup_event_time(struct perf_event *event)
731 {
732 	struct perf_cgroup_info *t;
733 
734 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
735 	return t->time;
736 }
737 
perf_cgroup_event_time_now(struct perf_event * event,u64 now)738 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
739 {
740 	struct perf_cgroup_info *t;
741 
742 	t = per_cpu_ptr(event->cgrp->info, event->cpu);
743 	if (!__load_acquire(&t->active))
744 		return t->time;
745 	now += READ_ONCE(t->timeoffset);
746 	return now;
747 }
748 
__update_cgrp_time(struct perf_cgroup_info * info,u64 now,bool adv)749 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
750 {
751 	if (adv)
752 		info->time += now - info->timestamp;
753 	info->timestamp = now;
754 	/*
755 	 * see update_context_time()
756 	 */
757 	WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
758 }
759 
update_cgrp_time_from_cpuctx(struct perf_cpu_context * cpuctx,bool final)760 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
761 {
762 	struct perf_cgroup *cgrp = cpuctx->cgrp;
763 	struct cgroup_subsys_state *css;
764 	struct perf_cgroup_info *info;
765 
766 	if (cgrp) {
767 		u64 now = perf_clock();
768 
769 		for (css = &cgrp->css; css; css = css->parent) {
770 			cgrp = container_of(css, struct perf_cgroup, css);
771 			info = this_cpu_ptr(cgrp->info);
772 
773 			__update_cgrp_time(info, now, true);
774 			if (final)
775 				__store_release(&info->active, 0);
776 		}
777 	}
778 }
779 
update_cgrp_time_from_event(struct perf_event * event)780 static inline void update_cgrp_time_from_event(struct perf_event *event)
781 {
782 	struct perf_cgroup_info *info;
783 
784 	/*
785 	 * ensure we access cgroup data only when needed and
786 	 * when we know the cgroup is pinned (css_get)
787 	 */
788 	if (!is_cgroup_event(event))
789 		return;
790 
791 	info = this_cpu_ptr(event->cgrp->info);
792 	/*
793 	 * Do not update time when cgroup is not active
794 	 */
795 	if (info->active)
796 		__update_cgrp_time(info, perf_clock(), true);
797 }
798 
799 static inline void
perf_cgroup_set_timestamp(struct perf_cpu_context * cpuctx)800 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
801 {
802 	struct perf_event_context *ctx = &cpuctx->ctx;
803 	struct perf_cgroup *cgrp = cpuctx->cgrp;
804 	struct perf_cgroup_info *info;
805 	struct cgroup_subsys_state *css;
806 
807 	/*
808 	 * ctx->lock held by caller
809 	 * ensure we do not access cgroup data
810 	 * unless we have the cgroup pinned (css_get)
811 	 */
812 	if (!cgrp)
813 		return;
814 
815 	WARN_ON_ONCE(!ctx->nr_cgroups);
816 
817 	for (css = &cgrp->css; css; css = css->parent) {
818 		cgrp = container_of(css, struct perf_cgroup, css);
819 		info = this_cpu_ptr(cgrp->info);
820 		__update_cgrp_time(info, ctx->timestamp, false);
821 		__store_release(&info->active, 1);
822 	}
823 }
824 
825 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
826 
827 /*
828  * reschedule events based on the cgroup constraint of task.
829  */
perf_cgroup_switch(struct task_struct * task)830 static void perf_cgroup_switch(struct task_struct *task)
831 {
832 	struct perf_cgroup *cgrp;
833 	struct perf_cpu_context *cpuctx, *tmp;
834 	struct list_head *list;
835 	unsigned long flags;
836 
837 	/*
838 	 * Disable interrupts and preemption to avoid this CPU's
839 	 * cgrp_cpuctx_entry to change under us.
840 	 */
841 	local_irq_save(flags);
842 
843 	cgrp = perf_cgroup_from_task(task, NULL);
844 
845 	list = this_cpu_ptr(&cgrp_cpuctx_list);
846 	list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
847 		WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
848 		if (READ_ONCE(cpuctx->cgrp) == cgrp)
849 			continue;
850 
851 		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
852 		perf_pmu_disable(cpuctx->ctx.pmu);
853 
854 		cpu_ctx_sched_out(cpuctx, EVENT_ALL);
855 		/*
856 		 * must not be done before ctxswout due
857 		 * to update_cgrp_time_from_cpuctx() in
858 		 * ctx_sched_out()
859 		 */
860 		cpuctx->cgrp = cgrp;
861 		/*
862 		 * set cgrp before ctxsw in to allow
863 		 * perf_cgroup_set_timestamp() in ctx_sched_in()
864 		 * to not have to pass task around
865 		 */
866 		cpu_ctx_sched_in(cpuctx, EVENT_ALL);
867 
868 		perf_pmu_enable(cpuctx->ctx.pmu);
869 		perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
870 	}
871 
872 	local_irq_restore(flags);
873 }
874 
perf_cgroup_ensure_storage(struct perf_event * event,struct cgroup_subsys_state * css)875 static int perf_cgroup_ensure_storage(struct perf_event *event,
876 				struct cgroup_subsys_state *css)
877 {
878 	struct perf_cpu_context *cpuctx;
879 	struct perf_event **storage;
880 	int cpu, heap_size, ret = 0;
881 
882 	/*
883 	 * Allow storage to have sufficent space for an iterator for each
884 	 * possibly nested cgroup plus an iterator for events with no cgroup.
885 	 */
886 	for (heap_size = 1; css; css = css->parent)
887 		heap_size++;
888 
889 	for_each_possible_cpu(cpu) {
890 		cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
891 		if (heap_size <= cpuctx->heap_size)
892 			continue;
893 
894 		storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
895 				       GFP_KERNEL, cpu_to_node(cpu));
896 		if (!storage) {
897 			ret = -ENOMEM;
898 			break;
899 		}
900 
901 		raw_spin_lock_irq(&cpuctx->ctx.lock);
902 		if (cpuctx->heap_size < heap_size) {
903 			swap(cpuctx->heap, storage);
904 			if (storage == cpuctx->heap_default)
905 				storage = NULL;
906 			cpuctx->heap_size = heap_size;
907 		}
908 		raw_spin_unlock_irq(&cpuctx->ctx.lock);
909 
910 		kfree(storage);
911 	}
912 
913 	return ret;
914 }
915 
perf_cgroup_connect(int fd,struct perf_event * event,struct perf_event_attr * attr,struct perf_event * group_leader)916 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
917 				      struct perf_event_attr *attr,
918 				      struct perf_event *group_leader)
919 {
920 	struct perf_cgroup *cgrp;
921 	struct cgroup_subsys_state *css;
922 	struct fd f = fdget(fd);
923 	int ret = 0;
924 
925 	if (!f.file)
926 		return -EBADF;
927 
928 	css = css_tryget_online_from_dir(f.file->f_path.dentry,
929 					 &perf_event_cgrp_subsys);
930 	if (IS_ERR(css)) {
931 		ret = PTR_ERR(css);
932 		goto out;
933 	}
934 
935 	ret = perf_cgroup_ensure_storage(event, css);
936 	if (ret)
937 		goto out;
938 
939 	cgrp = container_of(css, struct perf_cgroup, css);
940 	event->cgrp = cgrp;
941 
942 	/*
943 	 * all events in a group must monitor
944 	 * the same cgroup because a task belongs
945 	 * to only one perf cgroup at a time
946 	 */
947 	if (group_leader && group_leader->cgrp != cgrp) {
948 		perf_detach_cgroup(event);
949 		ret = -EINVAL;
950 	}
951 out:
952 	fdput(f);
953 	return ret;
954 }
955 
956 static inline void
perf_cgroup_event_enable(struct perf_event * event,struct perf_event_context * ctx)957 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
958 {
959 	struct perf_cpu_context *cpuctx;
960 
961 	if (!is_cgroup_event(event))
962 		return;
963 
964 	/*
965 	 * Because cgroup events are always per-cpu events,
966 	 * @ctx == &cpuctx->ctx.
967 	 */
968 	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
969 
970 	if (ctx->nr_cgroups++)
971 		return;
972 
973 	cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
974 	list_add(&cpuctx->cgrp_cpuctx_entry,
975 			per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
976 }
977 
978 static inline void
perf_cgroup_event_disable(struct perf_event * event,struct perf_event_context * ctx)979 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
980 {
981 	struct perf_cpu_context *cpuctx;
982 
983 	if (!is_cgroup_event(event))
984 		return;
985 
986 	/*
987 	 * Because cgroup events are always per-cpu events,
988 	 * @ctx == &cpuctx->ctx.
989 	 */
990 	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
991 
992 	if (--ctx->nr_cgroups)
993 		return;
994 
995 	cpuctx->cgrp = NULL;
996 	list_del(&cpuctx->cgrp_cpuctx_entry);
997 }
998 
999 #else /* !CONFIG_CGROUP_PERF */
1000 
1001 static inline bool
perf_cgroup_match(struct perf_event * event)1002 perf_cgroup_match(struct perf_event *event)
1003 {
1004 	return true;
1005 }
1006 
perf_detach_cgroup(struct perf_event * event)1007 static inline void perf_detach_cgroup(struct perf_event *event)
1008 {}
1009 
is_cgroup_event(struct perf_event * event)1010 static inline int is_cgroup_event(struct perf_event *event)
1011 {
1012 	return 0;
1013 }
1014 
update_cgrp_time_from_event(struct perf_event * event)1015 static inline void update_cgrp_time_from_event(struct perf_event *event)
1016 {
1017 }
1018 
update_cgrp_time_from_cpuctx(struct perf_cpu_context * cpuctx,bool final)1019 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1020 						bool final)
1021 {
1022 }
1023 
perf_cgroup_connect(pid_t pid,struct perf_event * event,struct perf_event_attr * attr,struct perf_event * group_leader)1024 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1025 				      struct perf_event_attr *attr,
1026 				      struct perf_event *group_leader)
1027 {
1028 	return -EINVAL;
1029 }
1030 
1031 static inline void
perf_cgroup_set_timestamp(struct perf_cpu_context * cpuctx)1032 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1033 {
1034 }
1035 
perf_cgroup_event_time(struct perf_event * event)1036 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1037 {
1038 	return 0;
1039 }
1040 
perf_cgroup_event_time_now(struct perf_event * event,u64 now)1041 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1042 {
1043 	return 0;
1044 }
1045 
1046 static inline void
perf_cgroup_event_enable(struct perf_event * event,struct perf_event_context * ctx)1047 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1048 {
1049 }
1050 
1051 static inline void
perf_cgroup_event_disable(struct perf_event * event,struct perf_event_context * ctx)1052 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1053 {
1054 }
1055 
perf_cgroup_switch(struct task_struct * task)1056 static void perf_cgroup_switch(struct task_struct *task)
1057 {
1058 }
1059 #endif
1060 
1061 /*
1062  * set default to be dependent on timer tick just
1063  * like original code
1064  */
1065 #define PERF_CPU_HRTIMER (1000 / HZ)
1066 /*
1067  * function must be called with interrupts disabled
1068  */
perf_mux_hrtimer_handler(struct hrtimer * hr)1069 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1070 {
1071 	struct perf_cpu_context *cpuctx;
1072 	bool rotations;
1073 
1074 	lockdep_assert_irqs_disabled();
1075 
1076 	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1077 	rotations = perf_rotate_context(cpuctx);
1078 
1079 	raw_spin_lock(&cpuctx->hrtimer_lock);
1080 	if (rotations)
1081 		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1082 	else
1083 		cpuctx->hrtimer_active = 0;
1084 	raw_spin_unlock(&cpuctx->hrtimer_lock);
1085 
1086 	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1087 }
1088 
__perf_mux_hrtimer_init(struct perf_cpu_context * cpuctx,int cpu)1089 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1090 {
1091 	struct hrtimer *timer = &cpuctx->hrtimer;
1092 	struct pmu *pmu = cpuctx->ctx.pmu;
1093 	u64 interval;
1094 
1095 	/* no multiplexing needed for SW PMU */
1096 	if (pmu->task_ctx_nr == perf_sw_context)
1097 		return;
1098 
1099 	/*
1100 	 * check default is sane, if not set then force to
1101 	 * default interval (1/tick)
1102 	 */
1103 	interval = pmu->hrtimer_interval_ms;
1104 	if (interval < 1)
1105 		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1106 
1107 	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1108 
1109 	raw_spin_lock_init(&cpuctx->hrtimer_lock);
1110 	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1111 	timer->function = perf_mux_hrtimer_handler;
1112 }
1113 
perf_mux_hrtimer_restart(struct perf_cpu_context * cpuctx)1114 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1115 {
1116 	struct hrtimer *timer = &cpuctx->hrtimer;
1117 	struct pmu *pmu = cpuctx->ctx.pmu;
1118 	unsigned long flags;
1119 
1120 	/* not for SW PMU */
1121 	if (pmu->task_ctx_nr == perf_sw_context)
1122 		return 0;
1123 
1124 	raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1125 	if (!cpuctx->hrtimer_active) {
1126 		cpuctx->hrtimer_active = 1;
1127 		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1128 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1129 	}
1130 	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1131 
1132 	return 0;
1133 }
1134 
perf_pmu_disable(struct pmu * pmu)1135 void perf_pmu_disable(struct pmu *pmu)
1136 {
1137 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1138 	if (!(*count)++)
1139 		pmu->pmu_disable(pmu);
1140 }
1141 
perf_pmu_enable(struct pmu * pmu)1142 void perf_pmu_enable(struct pmu *pmu)
1143 {
1144 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
1145 	if (!--(*count))
1146 		pmu->pmu_enable(pmu);
1147 }
1148 
1149 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1150 
1151 /*
1152  * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1153  * perf_event_task_tick() are fully serialized because they're strictly cpu
1154  * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1155  * disabled, while perf_event_task_tick is called from IRQ context.
1156  */
perf_event_ctx_activate(struct perf_event_context * ctx)1157 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1158 {
1159 	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1160 
1161 	lockdep_assert_irqs_disabled();
1162 
1163 	WARN_ON(!list_empty(&ctx->active_ctx_list));
1164 
1165 	list_add(&ctx->active_ctx_list, head);
1166 }
1167 
perf_event_ctx_deactivate(struct perf_event_context * ctx)1168 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1169 {
1170 	lockdep_assert_irqs_disabled();
1171 
1172 	WARN_ON(list_empty(&ctx->active_ctx_list));
1173 
1174 	list_del_init(&ctx->active_ctx_list);
1175 }
1176 
get_ctx(struct perf_event_context * ctx)1177 static void get_ctx(struct perf_event_context *ctx)
1178 {
1179 	refcount_inc(&ctx->refcount);
1180 }
1181 
alloc_task_ctx_data(struct pmu * pmu)1182 static void *alloc_task_ctx_data(struct pmu *pmu)
1183 {
1184 	if (pmu->task_ctx_cache)
1185 		return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1186 
1187 	return NULL;
1188 }
1189 
free_task_ctx_data(struct pmu * pmu,void * task_ctx_data)1190 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1191 {
1192 	if (pmu->task_ctx_cache && task_ctx_data)
1193 		kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1194 }
1195 
free_ctx(struct rcu_head * head)1196 static void free_ctx(struct rcu_head *head)
1197 {
1198 	struct perf_event_context *ctx;
1199 
1200 	ctx = container_of(head, struct perf_event_context, rcu_head);
1201 	free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1202 	kfree(ctx);
1203 }
1204 
put_ctx(struct perf_event_context * ctx)1205 static void put_ctx(struct perf_event_context *ctx)
1206 {
1207 	if (refcount_dec_and_test(&ctx->refcount)) {
1208 		if (ctx->parent_ctx)
1209 			put_ctx(ctx->parent_ctx);
1210 		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1211 			put_task_struct(ctx->task);
1212 		call_rcu(&ctx->rcu_head, free_ctx);
1213 	}
1214 }
1215 
1216 /*
1217  * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1218  * perf_pmu_migrate_context() we need some magic.
1219  *
1220  * Those places that change perf_event::ctx will hold both
1221  * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1222  *
1223  * Lock ordering is by mutex address. There are two other sites where
1224  * perf_event_context::mutex nests and those are:
1225  *
1226  *  - perf_event_exit_task_context()	[ child , 0 ]
1227  *      perf_event_exit_event()
1228  *        put_event()			[ parent, 1 ]
1229  *
1230  *  - perf_event_init_context()		[ parent, 0 ]
1231  *      inherit_task_group()
1232  *        inherit_group()
1233  *          inherit_event()
1234  *            perf_event_alloc()
1235  *              perf_init_event()
1236  *                perf_try_init_event()	[ child , 1 ]
1237  *
1238  * While it appears there is an obvious deadlock here -- the parent and child
1239  * nesting levels are inverted between the two. This is in fact safe because
1240  * life-time rules separate them. That is an exiting task cannot fork, and a
1241  * spawning task cannot (yet) exit.
1242  *
1243  * But remember that these are parent<->child context relations, and
1244  * migration does not affect children, therefore these two orderings should not
1245  * interact.
1246  *
1247  * The change in perf_event::ctx does not affect children (as claimed above)
1248  * because the sys_perf_event_open() case will install a new event and break
1249  * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1250  * concerned with cpuctx and that doesn't have children.
1251  *
1252  * The places that change perf_event::ctx will issue:
1253  *
1254  *   perf_remove_from_context();
1255  *   synchronize_rcu();
1256  *   perf_install_in_context();
1257  *
1258  * to affect the change. The remove_from_context() + synchronize_rcu() should
1259  * quiesce the event, after which we can install it in the new location. This
1260  * means that only external vectors (perf_fops, prctl) can perturb the event
1261  * while in transit. Therefore all such accessors should also acquire
1262  * perf_event_context::mutex to serialize against this.
1263  *
1264  * However; because event->ctx can change while we're waiting to acquire
1265  * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1266  * function.
1267  *
1268  * Lock order:
1269  *    exec_update_lock
1270  *	task_struct::perf_event_mutex
1271  *	  perf_event_context::mutex
1272  *	    perf_event::child_mutex;
1273  *	      perf_event_context::lock
1274  *	    perf_event::mmap_mutex
1275  *	    mmap_lock
1276  *	      perf_addr_filters_head::lock
1277  *
1278  *    cpu_hotplug_lock
1279  *      pmus_lock
1280  *	  cpuctx->mutex / perf_event_context::mutex
1281  */
1282 static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event * event,int nesting)1283 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1284 {
1285 	struct perf_event_context *ctx;
1286 
1287 again:
1288 	rcu_read_lock();
1289 	ctx = READ_ONCE(event->ctx);
1290 	if (!refcount_inc_not_zero(&ctx->refcount)) {
1291 		rcu_read_unlock();
1292 		goto again;
1293 	}
1294 	rcu_read_unlock();
1295 
1296 	mutex_lock_nested(&ctx->mutex, nesting);
1297 	if (event->ctx != ctx) {
1298 		mutex_unlock(&ctx->mutex);
1299 		put_ctx(ctx);
1300 		goto again;
1301 	}
1302 
1303 	return ctx;
1304 }
1305 
1306 static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event * event)1307 perf_event_ctx_lock(struct perf_event *event)
1308 {
1309 	return perf_event_ctx_lock_nested(event, 0);
1310 }
1311 
perf_event_ctx_unlock(struct perf_event * event,struct perf_event_context * ctx)1312 static void perf_event_ctx_unlock(struct perf_event *event,
1313 				  struct perf_event_context *ctx)
1314 {
1315 	mutex_unlock(&ctx->mutex);
1316 	put_ctx(ctx);
1317 }
1318 
1319 /*
1320  * This must be done under the ctx->lock, such as to serialize against
1321  * context_equiv(), therefore we cannot call put_ctx() since that might end up
1322  * calling scheduler related locks and ctx->lock nests inside those.
1323  */
1324 static __must_check struct perf_event_context *
unclone_ctx(struct perf_event_context * ctx)1325 unclone_ctx(struct perf_event_context *ctx)
1326 {
1327 	struct perf_event_context *parent_ctx = ctx->parent_ctx;
1328 
1329 	lockdep_assert_held(&ctx->lock);
1330 
1331 	if (parent_ctx)
1332 		ctx->parent_ctx = NULL;
1333 	ctx->generation++;
1334 
1335 	return parent_ctx;
1336 }
1337 
perf_event_pid_type(struct perf_event * event,struct task_struct * p,enum pid_type type)1338 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1339 				enum pid_type type)
1340 {
1341 	u32 nr;
1342 	/*
1343 	 * only top level events have the pid namespace they were created in
1344 	 */
1345 	if (event->parent)
1346 		event = event->parent;
1347 
1348 	nr = __task_pid_nr_ns(p, type, event->ns);
1349 	/* avoid -1 if it is idle thread or runs in another ns */
1350 	if (!nr && !pid_alive(p))
1351 		nr = -1;
1352 	return nr;
1353 }
1354 
perf_event_pid(struct perf_event * event,struct task_struct * p)1355 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1356 {
1357 	return perf_event_pid_type(event, p, PIDTYPE_TGID);
1358 }
1359 
perf_event_tid(struct perf_event * event,struct task_struct * p)1360 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1361 {
1362 	return perf_event_pid_type(event, p, PIDTYPE_PID);
1363 }
1364 
1365 /*
1366  * If we inherit events we want to return the parent event id
1367  * to userspace.
1368  */
primary_event_id(struct perf_event * event)1369 static u64 primary_event_id(struct perf_event *event)
1370 {
1371 	u64 id = event->id;
1372 
1373 	if (event->parent)
1374 		id = event->parent->id;
1375 
1376 	return id;
1377 }
1378 
1379 /*
1380  * Get the perf_event_context for a task and lock it.
1381  *
1382  * This has to cope with the fact that until it is locked,
1383  * the context could get moved to another task.
1384  */
1385 static struct perf_event_context *
perf_lock_task_context(struct task_struct * task,int ctxn,unsigned long * flags)1386 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1387 {
1388 	struct perf_event_context *ctx;
1389 
1390 retry:
1391 	/*
1392 	 * One of the few rules of preemptible RCU is that one cannot do
1393 	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1394 	 * part of the read side critical section was irqs-enabled -- see
1395 	 * rcu_read_unlock_special().
1396 	 *
1397 	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1398 	 * side critical section has interrupts disabled.
1399 	 */
1400 	local_irq_save(*flags);
1401 	rcu_read_lock();
1402 	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1403 	if (ctx) {
1404 		/*
1405 		 * If this context is a clone of another, it might
1406 		 * get swapped for another underneath us by
1407 		 * perf_event_task_sched_out, though the
1408 		 * rcu_read_lock() protects us from any context
1409 		 * getting freed.  Lock the context and check if it
1410 		 * got swapped before we could get the lock, and retry
1411 		 * if so.  If we locked the right context, then it
1412 		 * can't get swapped on us any more.
1413 		 */
1414 		raw_spin_lock(&ctx->lock);
1415 		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1416 			raw_spin_unlock(&ctx->lock);
1417 			rcu_read_unlock();
1418 			local_irq_restore(*flags);
1419 			goto retry;
1420 		}
1421 
1422 		if (ctx->task == TASK_TOMBSTONE ||
1423 		    !refcount_inc_not_zero(&ctx->refcount)) {
1424 			raw_spin_unlock(&ctx->lock);
1425 			ctx = NULL;
1426 		} else {
1427 			WARN_ON_ONCE(ctx->task != task);
1428 		}
1429 	}
1430 	rcu_read_unlock();
1431 	if (!ctx)
1432 		local_irq_restore(*flags);
1433 	return ctx;
1434 }
1435 
1436 /*
1437  * Get the context for a task and increment its pin_count so it
1438  * can't get swapped to another task.  This also increments its
1439  * reference count so that the context can't get freed.
1440  */
1441 static struct perf_event_context *
perf_pin_task_context(struct task_struct * task,int ctxn)1442 perf_pin_task_context(struct task_struct *task, int ctxn)
1443 {
1444 	struct perf_event_context *ctx;
1445 	unsigned long flags;
1446 
1447 	ctx = perf_lock_task_context(task, ctxn, &flags);
1448 	if (ctx) {
1449 		++ctx->pin_count;
1450 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1451 	}
1452 	return ctx;
1453 }
1454 
perf_unpin_context(struct perf_event_context * ctx)1455 static void perf_unpin_context(struct perf_event_context *ctx)
1456 {
1457 	unsigned long flags;
1458 
1459 	raw_spin_lock_irqsave(&ctx->lock, flags);
1460 	--ctx->pin_count;
1461 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1462 }
1463 
1464 /*
1465  * Update the record of the current time in a context.
1466  */
__update_context_time(struct perf_event_context * ctx,bool adv)1467 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1468 {
1469 	u64 now = perf_clock();
1470 
1471 	if (adv)
1472 		ctx->time += now - ctx->timestamp;
1473 	ctx->timestamp = now;
1474 
1475 	/*
1476 	 * The above: time' = time + (now - timestamp), can be re-arranged
1477 	 * into: time` = now + (time - timestamp), which gives a single value
1478 	 * offset to compute future time without locks on.
1479 	 *
1480 	 * See perf_event_time_now(), which can be used from NMI context where
1481 	 * it's (obviously) not possible to acquire ctx->lock in order to read
1482 	 * both the above values in a consistent manner.
1483 	 */
1484 	WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1485 }
1486 
update_context_time(struct perf_event_context * ctx)1487 static void update_context_time(struct perf_event_context *ctx)
1488 {
1489 	__update_context_time(ctx, true);
1490 }
1491 
perf_event_time(struct perf_event * event)1492 static u64 perf_event_time(struct perf_event *event)
1493 {
1494 	struct perf_event_context *ctx = event->ctx;
1495 
1496 	if (unlikely(!ctx))
1497 		return 0;
1498 
1499 	if (is_cgroup_event(event))
1500 		return perf_cgroup_event_time(event);
1501 
1502 	return ctx->time;
1503 }
1504 
perf_event_time_now(struct perf_event * event,u64 now)1505 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1506 {
1507 	struct perf_event_context *ctx = event->ctx;
1508 
1509 	if (unlikely(!ctx))
1510 		return 0;
1511 
1512 	if (is_cgroup_event(event))
1513 		return perf_cgroup_event_time_now(event, now);
1514 
1515 	if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1516 		return ctx->time;
1517 
1518 	now += READ_ONCE(ctx->timeoffset);
1519 	return now;
1520 }
1521 
get_event_type(struct perf_event * event)1522 static enum event_type_t get_event_type(struct perf_event *event)
1523 {
1524 	struct perf_event_context *ctx = event->ctx;
1525 	enum event_type_t event_type;
1526 
1527 	lockdep_assert_held(&ctx->lock);
1528 
1529 	/*
1530 	 * It's 'group type', really, because if our group leader is
1531 	 * pinned, so are we.
1532 	 */
1533 	if (event->group_leader != event)
1534 		event = event->group_leader;
1535 
1536 	event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1537 	if (!ctx->task)
1538 		event_type |= EVENT_CPU;
1539 
1540 	return event_type;
1541 }
1542 
1543 /*
1544  * Helper function to initialize event group nodes.
1545  */
init_event_group(struct perf_event * event)1546 static void init_event_group(struct perf_event *event)
1547 {
1548 	RB_CLEAR_NODE(&event->group_node);
1549 	event->group_index = 0;
1550 }
1551 
1552 /*
1553  * Extract pinned or flexible groups from the context
1554  * based on event attrs bits.
1555  */
1556 static struct perf_event_groups *
get_event_groups(struct perf_event * event,struct perf_event_context * ctx)1557 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1558 {
1559 	if (event->attr.pinned)
1560 		return &ctx->pinned_groups;
1561 	else
1562 		return &ctx->flexible_groups;
1563 }
1564 
1565 /*
1566  * Helper function to initializes perf_event_group trees.
1567  */
perf_event_groups_init(struct perf_event_groups * groups)1568 static void perf_event_groups_init(struct perf_event_groups *groups)
1569 {
1570 	groups->tree = RB_ROOT;
1571 	groups->index = 0;
1572 }
1573 
event_cgroup(const struct perf_event * event)1574 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1575 {
1576 	struct cgroup *cgroup = NULL;
1577 
1578 #ifdef CONFIG_CGROUP_PERF
1579 	if (event->cgrp)
1580 		cgroup = event->cgrp->css.cgroup;
1581 #endif
1582 
1583 	return cgroup;
1584 }
1585 
1586 /*
1587  * Compare function for event groups;
1588  *
1589  * Implements complex key that first sorts by CPU and then by virtual index
1590  * which provides ordering when rotating groups for the same CPU.
1591  */
1592 static __always_inline int
perf_event_groups_cmp(const int left_cpu,const struct cgroup * left_cgroup,const u64 left_group_index,const struct perf_event * right)1593 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1594 		      const u64 left_group_index, const struct perf_event *right)
1595 {
1596 	if (left_cpu < right->cpu)
1597 		return -1;
1598 	if (left_cpu > right->cpu)
1599 		return 1;
1600 
1601 #ifdef CONFIG_CGROUP_PERF
1602 	{
1603 		const struct cgroup *right_cgroup = event_cgroup(right);
1604 
1605 		if (left_cgroup != right_cgroup) {
1606 			if (!left_cgroup) {
1607 				/*
1608 				 * Left has no cgroup but right does, no
1609 				 * cgroups come first.
1610 				 */
1611 				return -1;
1612 			}
1613 			if (!right_cgroup) {
1614 				/*
1615 				 * Right has no cgroup but left does, no
1616 				 * cgroups come first.
1617 				 */
1618 				return 1;
1619 			}
1620 			/* Two dissimilar cgroups, order by id. */
1621 			if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1622 				return -1;
1623 
1624 			return 1;
1625 		}
1626 	}
1627 #endif
1628 
1629 	if (left_group_index < right->group_index)
1630 		return -1;
1631 	if (left_group_index > right->group_index)
1632 		return 1;
1633 
1634 	return 0;
1635 }
1636 
1637 #define __node_2_pe(node) \
1638 	rb_entry((node), struct perf_event, group_node)
1639 
__group_less(struct rb_node * a,const struct rb_node * b)1640 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1641 {
1642 	struct perf_event *e = __node_2_pe(a);
1643 	return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1644 				     __node_2_pe(b)) < 0;
1645 }
1646 
1647 struct __group_key {
1648 	int cpu;
1649 	struct cgroup *cgroup;
1650 };
1651 
__group_cmp(const void * key,const struct rb_node * node)1652 static inline int __group_cmp(const void *key, const struct rb_node *node)
1653 {
1654 	const struct __group_key *a = key;
1655 	const struct perf_event *b = __node_2_pe(node);
1656 
1657 	/* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1658 	return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1659 }
1660 
1661 /*
1662  * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1663  * key (see perf_event_groups_less). This places it last inside the CPU
1664  * subtree.
1665  */
1666 static void
perf_event_groups_insert(struct perf_event_groups * groups,struct perf_event * event)1667 perf_event_groups_insert(struct perf_event_groups *groups,
1668 			 struct perf_event *event)
1669 {
1670 	event->group_index = ++groups->index;
1671 
1672 	rb_add(&event->group_node, &groups->tree, __group_less);
1673 }
1674 
1675 /*
1676  * Helper function to insert event into the pinned or flexible groups.
1677  */
1678 static void
add_event_to_groups(struct perf_event * event,struct perf_event_context * ctx)1679 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1680 {
1681 	struct perf_event_groups *groups;
1682 
1683 	groups = get_event_groups(event, ctx);
1684 	perf_event_groups_insert(groups, event);
1685 }
1686 
1687 /*
1688  * Delete a group from a tree.
1689  */
1690 static void
perf_event_groups_delete(struct perf_event_groups * groups,struct perf_event * event)1691 perf_event_groups_delete(struct perf_event_groups *groups,
1692 			 struct perf_event *event)
1693 {
1694 	WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1695 		     RB_EMPTY_ROOT(&groups->tree));
1696 
1697 	rb_erase(&event->group_node, &groups->tree);
1698 	init_event_group(event);
1699 }
1700 
1701 /*
1702  * Helper function to delete event from its groups.
1703  */
1704 static void
del_event_from_groups(struct perf_event * event,struct perf_event_context * ctx)1705 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1706 {
1707 	struct perf_event_groups *groups;
1708 
1709 	groups = get_event_groups(event, ctx);
1710 	perf_event_groups_delete(groups, event);
1711 }
1712 
1713 /*
1714  * Get the leftmost event in the cpu/cgroup subtree.
1715  */
1716 static struct perf_event *
perf_event_groups_first(struct perf_event_groups * groups,int cpu,struct cgroup * cgrp)1717 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1718 			struct cgroup *cgrp)
1719 {
1720 	struct __group_key key = {
1721 		.cpu = cpu,
1722 		.cgroup = cgrp,
1723 	};
1724 	struct rb_node *node;
1725 
1726 	node = rb_find_first(&key, &groups->tree, __group_cmp);
1727 	if (node)
1728 		return __node_2_pe(node);
1729 
1730 	return NULL;
1731 }
1732 
1733 /*
1734  * Like rb_entry_next_safe() for the @cpu subtree.
1735  */
1736 static struct perf_event *
perf_event_groups_next(struct perf_event * event)1737 perf_event_groups_next(struct perf_event *event)
1738 {
1739 	struct __group_key key = {
1740 		.cpu = event->cpu,
1741 		.cgroup = event_cgroup(event),
1742 	};
1743 	struct rb_node *next;
1744 
1745 	next = rb_next_match(&key, &event->group_node, __group_cmp);
1746 	if (next)
1747 		return __node_2_pe(next);
1748 
1749 	return NULL;
1750 }
1751 
1752 /*
1753  * Iterate through the whole groups tree.
1754  */
1755 #define perf_event_groups_for_each(event, groups)			\
1756 	for (event = rb_entry_safe(rb_first(&((groups)->tree)),		\
1757 				typeof(*event), group_node); event;	\
1758 		event = rb_entry_safe(rb_next(&event->group_node),	\
1759 				typeof(*event), group_node))
1760 
1761 /*
1762  * Add an event from the lists for its context.
1763  * Must be called with ctx->mutex and ctx->lock held.
1764  */
1765 static void
list_add_event(struct perf_event * event,struct perf_event_context * ctx)1766 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1767 {
1768 	lockdep_assert_held(&ctx->lock);
1769 
1770 	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1771 	event->attach_state |= PERF_ATTACH_CONTEXT;
1772 
1773 	event->tstamp = perf_event_time(event);
1774 
1775 	/*
1776 	 * If we're a stand alone event or group leader, we go to the context
1777 	 * list, group events are kept attached to the group so that
1778 	 * perf_group_detach can, at all times, locate all siblings.
1779 	 */
1780 	if (event->group_leader == event) {
1781 		event->group_caps = event->event_caps;
1782 		add_event_to_groups(event, ctx);
1783 	}
1784 
1785 	list_add_rcu(&event->event_entry, &ctx->event_list);
1786 	ctx->nr_events++;
1787 	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1788 		ctx->nr_user++;
1789 	if (event->attr.inherit_stat)
1790 		ctx->nr_stat++;
1791 
1792 	if (event->state > PERF_EVENT_STATE_OFF)
1793 		perf_cgroup_event_enable(event, ctx);
1794 
1795 	ctx->generation++;
1796 }
1797 
1798 /*
1799  * Initialize event state based on the perf_event_attr::disabled.
1800  */
perf_event__state_init(struct perf_event * event)1801 static inline void perf_event__state_init(struct perf_event *event)
1802 {
1803 	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1804 					      PERF_EVENT_STATE_INACTIVE;
1805 }
1806 
__perf_event_read_size(struct perf_event * event,int nr_siblings)1807 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1808 {
1809 	int entry = sizeof(u64); /* value */
1810 	int size = 0;
1811 	int nr = 1;
1812 
1813 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1814 		size += sizeof(u64);
1815 
1816 	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1817 		size += sizeof(u64);
1818 
1819 	if (event->attr.read_format & PERF_FORMAT_ID)
1820 		entry += sizeof(u64);
1821 
1822 	if (event->attr.read_format & PERF_FORMAT_GROUP) {
1823 		nr += nr_siblings;
1824 		size += sizeof(u64);
1825 	}
1826 
1827 	size += entry * nr;
1828 	event->read_size = size;
1829 }
1830 
__perf_event_header_size(struct perf_event * event,u64 sample_type)1831 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1832 {
1833 	struct perf_sample_data *data;
1834 	u16 size = 0;
1835 
1836 	if (sample_type & PERF_SAMPLE_IP)
1837 		size += sizeof(data->ip);
1838 
1839 	if (sample_type & PERF_SAMPLE_ADDR)
1840 		size += sizeof(data->addr);
1841 
1842 	if (sample_type & PERF_SAMPLE_PERIOD)
1843 		size += sizeof(data->period);
1844 
1845 	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1846 		size += sizeof(data->weight.full);
1847 
1848 	if (sample_type & PERF_SAMPLE_READ)
1849 		size += event->read_size;
1850 
1851 	if (sample_type & PERF_SAMPLE_DATA_SRC)
1852 		size += sizeof(data->data_src.val);
1853 
1854 	if (sample_type & PERF_SAMPLE_TRANSACTION)
1855 		size += sizeof(data->txn);
1856 
1857 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1858 		size += sizeof(data->phys_addr);
1859 
1860 	if (sample_type & PERF_SAMPLE_CGROUP)
1861 		size += sizeof(data->cgroup);
1862 
1863 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1864 		size += sizeof(data->data_page_size);
1865 
1866 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1867 		size += sizeof(data->code_page_size);
1868 
1869 	event->header_size = size;
1870 }
1871 
1872 /*
1873  * Called at perf_event creation and when events are attached/detached from a
1874  * group.
1875  */
perf_event__header_size(struct perf_event * event)1876 static void perf_event__header_size(struct perf_event *event)
1877 {
1878 	__perf_event_read_size(event,
1879 			       event->group_leader->nr_siblings);
1880 	__perf_event_header_size(event, event->attr.sample_type);
1881 }
1882 
perf_event__id_header_size(struct perf_event * event)1883 static void perf_event__id_header_size(struct perf_event *event)
1884 {
1885 	struct perf_sample_data *data;
1886 	u64 sample_type = event->attr.sample_type;
1887 	u16 size = 0;
1888 
1889 	if (sample_type & PERF_SAMPLE_TID)
1890 		size += sizeof(data->tid_entry);
1891 
1892 	if (sample_type & PERF_SAMPLE_TIME)
1893 		size += sizeof(data->time);
1894 
1895 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
1896 		size += sizeof(data->id);
1897 
1898 	if (sample_type & PERF_SAMPLE_ID)
1899 		size += sizeof(data->id);
1900 
1901 	if (sample_type & PERF_SAMPLE_STREAM_ID)
1902 		size += sizeof(data->stream_id);
1903 
1904 	if (sample_type & PERF_SAMPLE_CPU)
1905 		size += sizeof(data->cpu_entry);
1906 
1907 	event->id_header_size = size;
1908 }
1909 
perf_event_validate_size(struct perf_event * event)1910 static bool perf_event_validate_size(struct perf_event *event)
1911 {
1912 	/*
1913 	 * The values computed here will be over-written when we actually
1914 	 * attach the event.
1915 	 */
1916 	__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1917 	__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1918 	perf_event__id_header_size(event);
1919 
1920 	/*
1921 	 * Sum the lot; should not exceed the 64k limit we have on records.
1922 	 * Conservative limit to allow for callchains and other variable fields.
1923 	 */
1924 	if (event->read_size + event->header_size +
1925 	    event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1926 		return false;
1927 
1928 	return true;
1929 }
1930 
perf_group_attach(struct perf_event * event)1931 static void perf_group_attach(struct perf_event *event)
1932 {
1933 	struct perf_event *group_leader = event->group_leader, *pos;
1934 
1935 	lockdep_assert_held(&event->ctx->lock);
1936 
1937 	/*
1938 	 * We can have double attach due to group movement in perf_event_open.
1939 	 */
1940 	if (event->attach_state & PERF_ATTACH_GROUP)
1941 		return;
1942 
1943 	event->attach_state |= PERF_ATTACH_GROUP;
1944 
1945 	if (group_leader == event)
1946 		return;
1947 
1948 	WARN_ON_ONCE(group_leader->ctx != event->ctx);
1949 
1950 	group_leader->group_caps &= event->event_caps;
1951 
1952 	list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1953 	group_leader->nr_siblings++;
1954 
1955 	perf_event__header_size(group_leader);
1956 
1957 	for_each_sibling_event(pos, group_leader)
1958 		perf_event__header_size(pos);
1959 }
1960 
1961 /*
1962  * Remove an event from the lists for its context.
1963  * Must be called with ctx->mutex and ctx->lock held.
1964  */
1965 static void
list_del_event(struct perf_event * event,struct perf_event_context * ctx)1966 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1967 {
1968 	WARN_ON_ONCE(event->ctx != ctx);
1969 	lockdep_assert_held(&ctx->lock);
1970 
1971 	/*
1972 	 * We can have double detach due to exit/hot-unplug + close.
1973 	 */
1974 	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1975 		return;
1976 
1977 	event->attach_state &= ~PERF_ATTACH_CONTEXT;
1978 
1979 	ctx->nr_events--;
1980 	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1981 		ctx->nr_user--;
1982 	if (event->attr.inherit_stat)
1983 		ctx->nr_stat--;
1984 
1985 	list_del_rcu(&event->event_entry);
1986 
1987 	if (event->group_leader == event)
1988 		del_event_from_groups(event, ctx);
1989 
1990 	/*
1991 	 * If event was in error state, then keep it
1992 	 * that way, otherwise bogus counts will be
1993 	 * returned on read(). The only way to get out
1994 	 * of error state is by explicit re-enabling
1995 	 * of the event
1996 	 */
1997 	if (event->state > PERF_EVENT_STATE_OFF) {
1998 		perf_cgroup_event_disable(event, ctx);
1999 		perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2000 	}
2001 
2002 	ctx->generation++;
2003 }
2004 
2005 static int
perf_aux_output_match(struct perf_event * event,struct perf_event * aux_event)2006 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2007 {
2008 	if (!has_aux(aux_event))
2009 		return 0;
2010 
2011 	if (!event->pmu->aux_output_match)
2012 		return 0;
2013 
2014 	return event->pmu->aux_output_match(aux_event);
2015 }
2016 
2017 static void put_event(struct perf_event *event);
2018 static void event_sched_out(struct perf_event *event,
2019 			    struct perf_cpu_context *cpuctx,
2020 			    struct perf_event_context *ctx);
2021 
perf_put_aux_event(struct perf_event * event)2022 static void perf_put_aux_event(struct perf_event *event)
2023 {
2024 	struct perf_event_context *ctx = event->ctx;
2025 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2026 	struct perf_event *iter;
2027 
2028 	/*
2029 	 * If event uses aux_event tear down the link
2030 	 */
2031 	if (event->aux_event) {
2032 		iter = event->aux_event;
2033 		event->aux_event = NULL;
2034 		put_event(iter);
2035 		return;
2036 	}
2037 
2038 	/*
2039 	 * If the event is an aux_event, tear down all links to
2040 	 * it from other events.
2041 	 */
2042 	for_each_sibling_event(iter, event->group_leader) {
2043 		if (iter->aux_event != event)
2044 			continue;
2045 
2046 		iter->aux_event = NULL;
2047 		put_event(event);
2048 
2049 		/*
2050 		 * If it's ACTIVE, schedule it out and put it into ERROR
2051 		 * state so that we don't try to schedule it again. Note
2052 		 * that perf_event_enable() will clear the ERROR status.
2053 		 */
2054 		event_sched_out(iter, cpuctx, ctx);
2055 		perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2056 	}
2057 }
2058 
perf_need_aux_event(struct perf_event * event)2059 static bool perf_need_aux_event(struct perf_event *event)
2060 {
2061 	return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2062 }
2063 
perf_get_aux_event(struct perf_event * event,struct perf_event * group_leader)2064 static int perf_get_aux_event(struct perf_event *event,
2065 			      struct perf_event *group_leader)
2066 {
2067 	/*
2068 	 * Our group leader must be an aux event if we want to be
2069 	 * an aux_output. This way, the aux event will precede its
2070 	 * aux_output events in the group, and therefore will always
2071 	 * schedule first.
2072 	 */
2073 	if (!group_leader)
2074 		return 0;
2075 
2076 	/*
2077 	 * aux_output and aux_sample_size are mutually exclusive.
2078 	 */
2079 	if (event->attr.aux_output && event->attr.aux_sample_size)
2080 		return 0;
2081 
2082 	if (event->attr.aux_output &&
2083 	    !perf_aux_output_match(event, group_leader))
2084 		return 0;
2085 
2086 	if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2087 		return 0;
2088 
2089 	if (!atomic_long_inc_not_zero(&group_leader->refcount))
2090 		return 0;
2091 
2092 	/*
2093 	 * Link aux_outputs to their aux event; this is undone in
2094 	 * perf_group_detach() by perf_put_aux_event(). When the
2095 	 * group in torn down, the aux_output events loose their
2096 	 * link to the aux_event and can't schedule any more.
2097 	 */
2098 	event->aux_event = group_leader;
2099 
2100 	return 1;
2101 }
2102 
get_event_list(struct perf_event * event)2103 static inline struct list_head *get_event_list(struct perf_event *event)
2104 {
2105 	struct perf_event_context *ctx = event->ctx;
2106 	return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2107 }
2108 
2109 /*
2110  * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2111  * cannot exist on their own, schedule them out and move them into the ERROR
2112  * state. Also see _perf_event_enable(), it will not be able to recover
2113  * this ERROR state.
2114  */
perf_remove_sibling_event(struct perf_event * event)2115 static inline void perf_remove_sibling_event(struct perf_event *event)
2116 {
2117 	struct perf_event_context *ctx = event->ctx;
2118 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2119 
2120 	event_sched_out(event, cpuctx, ctx);
2121 	perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2122 }
2123 
perf_group_detach(struct perf_event * event)2124 static void perf_group_detach(struct perf_event *event)
2125 {
2126 	struct perf_event *leader = event->group_leader;
2127 	struct perf_event *sibling, *tmp;
2128 	struct perf_event_context *ctx = event->ctx;
2129 
2130 	lockdep_assert_held(&ctx->lock);
2131 
2132 	/*
2133 	 * We can have double detach due to exit/hot-unplug + close.
2134 	 */
2135 	if (!(event->attach_state & PERF_ATTACH_GROUP))
2136 		return;
2137 
2138 	event->attach_state &= ~PERF_ATTACH_GROUP;
2139 
2140 	perf_put_aux_event(event);
2141 
2142 	/*
2143 	 * If this is a sibling, remove it from its group.
2144 	 */
2145 	if (leader != event) {
2146 		list_del_init(&event->sibling_list);
2147 		event->group_leader->nr_siblings--;
2148 		goto out;
2149 	}
2150 
2151 	/*
2152 	 * If this was a group event with sibling events then
2153 	 * upgrade the siblings to singleton events by adding them
2154 	 * to whatever list we are on.
2155 	 */
2156 	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2157 
2158 		if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2159 			perf_remove_sibling_event(sibling);
2160 
2161 		sibling->group_leader = sibling;
2162 		list_del_init(&sibling->sibling_list);
2163 
2164 		/* Inherit group flags from the previous leader */
2165 		sibling->group_caps = event->group_caps;
2166 
2167 		if (!RB_EMPTY_NODE(&event->group_node)) {
2168 			add_event_to_groups(sibling, event->ctx);
2169 
2170 			if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2171 				list_add_tail(&sibling->active_list, get_event_list(sibling));
2172 		}
2173 
2174 		WARN_ON_ONCE(sibling->ctx != event->ctx);
2175 	}
2176 
2177 out:
2178 	for_each_sibling_event(tmp, leader)
2179 		perf_event__header_size(tmp);
2180 
2181 	perf_event__header_size(leader);
2182 }
2183 
2184 static void sync_child_event(struct perf_event *child_event);
2185 
perf_child_detach(struct perf_event * event)2186 static void perf_child_detach(struct perf_event *event)
2187 {
2188 	struct perf_event *parent_event = event->parent;
2189 
2190 	if (!(event->attach_state & PERF_ATTACH_CHILD))
2191 		return;
2192 
2193 	event->attach_state &= ~PERF_ATTACH_CHILD;
2194 
2195 	if (WARN_ON_ONCE(!parent_event))
2196 		return;
2197 
2198 	lockdep_assert_held(&parent_event->child_mutex);
2199 
2200 	sync_child_event(event);
2201 	list_del_init(&event->child_list);
2202 }
2203 
is_orphaned_event(struct perf_event * event)2204 static bool is_orphaned_event(struct perf_event *event)
2205 {
2206 	return event->state == PERF_EVENT_STATE_DEAD;
2207 }
2208 
__pmu_filter_match(struct perf_event * event)2209 static inline int __pmu_filter_match(struct perf_event *event)
2210 {
2211 	struct pmu *pmu = event->pmu;
2212 	return pmu->filter_match ? pmu->filter_match(event) : 1;
2213 }
2214 
2215 /*
2216  * Check whether we should attempt to schedule an event group based on
2217  * PMU-specific filtering. An event group can consist of HW and SW events,
2218  * potentially with a SW leader, so we must check all the filters, to
2219  * determine whether a group is schedulable:
2220  */
pmu_filter_match(struct perf_event * event)2221 static inline int pmu_filter_match(struct perf_event *event)
2222 {
2223 	struct perf_event *sibling;
2224 
2225 	if (!__pmu_filter_match(event))
2226 		return 0;
2227 
2228 	for_each_sibling_event(sibling, event) {
2229 		if (!__pmu_filter_match(sibling))
2230 			return 0;
2231 	}
2232 
2233 	return 1;
2234 }
2235 
2236 static inline int
event_filter_match(struct perf_event * event)2237 event_filter_match(struct perf_event *event)
2238 {
2239 	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2240 	       perf_cgroup_match(event) && pmu_filter_match(event);
2241 }
2242 
2243 static void
event_sched_out(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2244 event_sched_out(struct perf_event *event,
2245 		  struct perf_cpu_context *cpuctx,
2246 		  struct perf_event_context *ctx)
2247 {
2248 	enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2249 
2250 	WARN_ON_ONCE(event->ctx != ctx);
2251 	lockdep_assert_held(&ctx->lock);
2252 
2253 	if (event->state != PERF_EVENT_STATE_ACTIVE)
2254 		return;
2255 
2256 	/*
2257 	 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2258 	 * we can schedule events _OUT_ individually through things like
2259 	 * __perf_remove_from_context().
2260 	 */
2261 	list_del_init(&event->active_list);
2262 
2263 	perf_pmu_disable(event->pmu);
2264 
2265 	event->pmu->del(event, 0);
2266 	event->oncpu = -1;
2267 
2268 	if (READ_ONCE(event->pending_disable) >= 0) {
2269 		WRITE_ONCE(event->pending_disable, -1);
2270 		perf_cgroup_event_disable(event, ctx);
2271 		state = PERF_EVENT_STATE_OFF;
2272 	}
2273 	perf_event_set_state(event, state);
2274 
2275 	if (!is_software_event(event))
2276 		cpuctx->active_oncpu--;
2277 	if (!--ctx->nr_active)
2278 		perf_event_ctx_deactivate(ctx);
2279 	if (event->attr.freq && event->attr.sample_freq)
2280 		ctx->nr_freq--;
2281 	if (event->attr.exclusive || !cpuctx->active_oncpu)
2282 		cpuctx->exclusive = 0;
2283 
2284 	perf_pmu_enable(event->pmu);
2285 }
2286 
2287 static void
group_sched_out(struct perf_event * group_event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2288 group_sched_out(struct perf_event *group_event,
2289 		struct perf_cpu_context *cpuctx,
2290 		struct perf_event_context *ctx)
2291 {
2292 	struct perf_event *event;
2293 
2294 	if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2295 		return;
2296 
2297 	perf_pmu_disable(ctx->pmu);
2298 
2299 	event_sched_out(group_event, cpuctx, ctx);
2300 
2301 	/*
2302 	 * Schedule out siblings (if any):
2303 	 */
2304 	for_each_sibling_event(event, group_event)
2305 		event_sched_out(event, cpuctx, ctx);
2306 
2307 	perf_pmu_enable(ctx->pmu);
2308 }
2309 
2310 #define DETACH_GROUP	0x01UL
2311 #define DETACH_CHILD	0x02UL
2312 
2313 /*
2314  * Cross CPU call to remove a performance event
2315  *
2316  * We disable the event on the hardware level first. After that we
2317  * remove it from the context list.
2318  */
2319 static void
__perf_remove_from_context(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2320 __perf_remove_from_context(struct perf_event *event,
2321 			   struct perf_cpu_context *cpuctx,
2322 			   struct perf_event_context *ctx,
2323 			   void *info)
2324 {
2325 	unsigned long flags = (unsigned long)info;
2326 
2327 	if (ctx->is_active & EVENT_TIME) {
2328 		update_context_time(ctx);
2329 		update_cgrp_time_from_cpuctx(cpuctx, false);
2330 	}
2331 
2332 	event_sched_out(event, cpuctx, ctx);
2333 	if (flags & DETACH_GROUP)
2334 		perf_group_detach(event);
2335 	if (flags & DETACH_CHILD)
2336 		perf_child_detach(event);
2337 	list_del_event(event, ctx);
2338 
2339 	if (!ctx->nr_events && ctx->is_active) {
2340 		if (ctx == &cpuctx->ctx)
2341 			update_cgrp_time_from_cpuctx(cpuctx, true);
2342 
2343 		ctx->is_active = 0;
2344 		ctx->rotate_necessary = 0;
2345 		if (ctx->task) {
2346 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2347 			cpuctx->task_ctx = NULL;
2348 		}
2349 	}
2350 }
2351 
2352 /*
2353  * Remove the event from a task's (or a CPU's) list of events.
2354  *
2355  * If event->ctx is a cloned context, callers must make sure that
2356  * every task struct that event->ctx->task could possibly point to
2357  * remains valid.  This is OK when called from perf_release since
2358  * that only calls us on the top-level context, which can't be a clone.
2359  * When called from perf_event_exit_task, it's OK because the
2360  * context has been detached from its task.
2361  */
perf_remove_from_context(struct perf_event * event,unsigned long flags)2362 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2363 {
2364 	struct perf_event_context *ctx = event->ctx;
2365 
2366 	lockdep_assert_held(&ctx->mutex);
2367 
2368 	/*
2369 	 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2370 	 * to work in the face of TASK_TOMBSTONE, unlike every other
2371 	 * event_function_call() user.
2372 	 */
2373 	raw_spin_lock_irq(&ctx->lock);
2374 	/*
2375 	 * Cgroup events are per-cpu events, and must IPI because of
2376 	 * cgrp_cpuctx_list.
2377 	 */
2378 	if (!ctx->is_active && !is_cgroup_event(event)) {
2379 		__perf_remove_from_context(event, __get_cpu_context(ctx),
2380 					   ctx, (void *)flags);
2381 		raw_spin_unlock_irq(&ctx->lock);
2382 		return;
2383 	}
2384 	raw_spin_unlock_irq(&ctx->lock);
2385 
2386 	event_function_call(event, __perf_remove_from_context, (void *)flags);
2387 }
2388 
2389 /*
2390  * Cross CPU call to disable a performance event
2391  */
__perf_event_disable(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2392 static void __perf_event_disable(struct perf_event *event,
2393 				 struct perf_cpu_context *cpuctx,
2394 				 struct perf_event_context *ctx,
2395 				 void *info)
2396 {
2397 	if (event->state < PERF_EVENT_STATE_INACTIVE)
2398 		return;
2399 
2400 	if (ctx->is_active & EVENT_TIME) {
2401 		update_context_time(ctx);
2402 		update_cgrp_time_from_event(event);
2403 	}
2404 
2405 	if (event == event->group_leader)
2406 		group_sched_out(event, cpuctx, ctx);
2407 	else
2408 		event_sched_out(event, cpuctx, ctx);
2409 
2410 	perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2411 	perf_cgroup_event_disable(event, ctx);
2412 }
2413 
2414 /*
2415  * Disable an event.
2416  *
2417  * If event->ctx is a cloned context, callers must make sure that
2418  * every task struct that event->ctx->task could possibly point to
2419  * remains valid.  This condition is satisfied when called through
2420  * perf_event_for_each_child or perf_event_for_each because they
2421  * hold the top-level event's child_mutex, so any descendant that
2422  * goes to exit will block in perf_event_exit_event().
2423  *
2424  * When called from perf_pending_event it's OK because event->ctx
2425  * is the current context on this CPU and preemption is disabled,
2426  * hence we can't get into perf_event_task_sched_out for this context.
2427  */
_perf_event_disable(struct perf_event * event)2428 static void _perf_event_disable(struct perf_event *event)
2429 {
2430 	struct perf_event_context *ctx = event->ctx;
2431 
2432 	raw_spin_lock_irq(&ctx->lock);
2433 	if (event->state <= PERF_EVENT_STATE_OFF) {
2434 		raw_spin_unlock_irq(&ctx->lock);
2435 		return;
2436 	}
2437 	raw_spin_unlock_irq(&ctx->lock);
2438 
2439 	event_function_call(event, __perf_event_disable, NULL);
2440 }
2441 
perf_event_disable_local(struct perf_event * event)2442 void perf_event_disable_local(struct perf_event *event)
2443 {
2444 	event_function_local(event, __perf_event_disable, NULL);
2445 }
2446 
2447 /*
2448  * Strictly speaking kernel users cannot create groups and therefore this
2449  * interface does not need the perf_event_ctx_lock() magic.
2450  */
perf_event_disable(struct perf_event * event)2451 void perf_event_disable(struct perf_event *event)
2452 {
2453 	struct perf_event_context *ctx;
2454 
2455 	ctx = perf_event_ctx_lock(event);
2456 	_perf_event_disable(event);
2457 	perf_event_ctx_unlock(event, ctx);
2458 }
2459 EXPORT_SYMBOL_GPL(perf_event_disable);
2460 
perf_event_disable_inatomic(struct perf_event * event)2461 void perf_event_disable_inatomic(struct perf_event *event)
2462 {
2463 	WRITE_ONCE(event->pending_disable, smp_processor_id());
2464 	/* can fail, see perf_pending_event_disable() */
2465 	irq_work_queue(&event->pending);
2466 }
2467 
2468 #define MAX_INTERRUPTS (~0ULL)
2469 
2470 static void perf_log_throttle(struct perf_event *event, int enable);
2471 static void perf_log_itrace_start(struct perf_event *event);
2472 
2473 static int
event_sched_in(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2474 event_sched_in(struct perf_event *event,
2475 		 struct perf_cpu_context *cpuctx,
2476 		 struct perf_event_context *ctx)
2477 {
2478 	int ret = 0;
2479 
2480 	WARN_ON_ONCE(event->ctx != ctx);
2481 
2482 	lockdep_assert_held(&ctx->lock);
2483 
2484 	if (event->state <= PERF_EVENT_STATE_OFF)
2485 		return 0;
2486 
2487 	WRITE_ONCE(event->oncpu, smp_processor_id());
2488 	/*
2489 	 * Order event::oncpu write to happen before the ACTIVE state is
2490 	 * visible. This allows perf_event_{stop,read}() to observe the correct
2491 	 * ->oncpu if it sees ACTIVE.
2492 	 */
2493 	smp_wmb();
2494 	perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2495 
2496 	/*
2497 	 * Unthrottle events, since we scheduled we might have missed several
2498 	 * ticks already, also for a heavily scheduling task there is little
2499 	 * guarantee it'll get a tick in a timely manner.
2500 	 */
2501 	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2502 		perf_log_throttle(event, 1);
2503 		event->hw.interrupts = 0;
2504 	}
2505 
2506 	perf_pmu_disable(event->pmu);
2507 
2508 	perf_log_itrace_start(event);
2509 
2510 	if (event->pmu->add(event, PERF_EF_START)) {
2511 		perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2512 		event->oncpu = -1;
2513 		ret = -EAGAIN;
2514 		goto out;
2515 	}
2516 
2517 	if (!is_software_event(event))
2518 		cpuctx->active_oncpu++;
2519 	if (!ctx->nr_active++)
2520 		perf_event_ctx_activate(ctx);
2521 	if (event->attr.freq && event->attr.sample_freq)
2522 		ctx->nr_freq++;
2523 
2524 	if (event->attr.exclusive)
2525 		cpuctx->exclusive = 1;
2526 
2527 out:
2528 	perf_pmu_enable(event->pmu);
2529 
2530 	return ret;
2531 }
2532 
2533 static int
group_sched_in(struct perf_event * group_event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2534 group_sched_in(struct perf_event *group_event,
2535 	       struct perf_cpu_context *cpuctx,
2536 	       struct perf_event_context *ctx)
2537 {
2538 	struct perf_event *event, *partial_group = NULL;
2539 	struct pmu *pmu = ctx->pmu;
2540 
2541 	if (group_event->state == PERF_EVENT_STATE_OFF)
2542 		return 0;
2543 
2544 	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2545 
2546 	if (event_sched_in(group_event, cpuctx, ctx))
2547 		goto error;
2548 
2549 	/*
2550 	 * Schedule in siblings as one group (if any):
2551 	 */
2552 	for_each_sibling_event(event, group_event) {
2553 		if (event_sched_in(event, cpuctx, ctx)) {
2554 			partial_group = event;
2555 			goto group_error;
2556 		}
2557 	}
2558 
2559 	if (!pmu->commit_txn(pmu))
2560 		return 0;
2561 
2562 group_error:
2563 	/*
2564 	 * Groups can be scheduled in as one unit only, so undo any
2565 	 * partial group before returning:
2566 	 * The events up to the failed event are scheduled out normally.
2567 	 */
2568 	for_each_sibling_event(event, group_event) {
2569 		if (event == partial_group)
2570 			break;
2571 
2572 		event_sched_out(event, cpuctx, ctx);
2573 	}
2574 	event_sched_out(group_event, cpuctx, ctx);
2575 
2576 error:
2577 	pmu->cancel_txn(pmu);
2578 	return -EAGAIN;
2579 }
2580 
2581 /*
2582  * Work out whether we can put this event group on the CPU now.
2583  */
group_can_go_on(struct perf_event * event,struct perf_cpu_context * cpuctx,int can_add_hw)2584 static int group_can_go_on(struct perf_event *event,
2585 			   struct perf_cpu_context *cpuctx,
2586 			   int can_add_hw)
2587 {
2588 	/*
2589 	 * Groups consisting entirely of software events can always go on.
2590 	 */
2591 	if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2592 		return 1;
2593 	/*
2594 	 * If an exclusive group is already on, no other hardware
2595 	 * events can go on.
2596 	 */
2597 	if (cpuctx->exclusive)
2598 		return 0;
2599 	/*
2600 	 * If this group is exclusive and there are already
2601 	 * events on the CPU, it can't go on.
2602 	 */
2603 	if (event->attr.exclusive && !list_empty(get_event_list(event)))
2604 		return 0;
2605 	/*
2606 	 * Otherwise, try to add it if all previous groups were able
2607 	 * to go on.
2608 	 */
2609 	return can_add_hw;
2610 }
2611 
add_event_to_ctx(struct perf_event * event,struct perf_event_context * ctx)2612 static void add_event_to_ctx(struct perf_event *event,
2613 			       struct perf_event_context *ctx)
2614 {
2615 	list_add_event(event, ctx);
2616 	perf_group_attach(event);
2617 }
2618 
2619 static void ctx_sched_out(struct perf_event_context *ctx,
2620 			  struct perf_cpu_context *cpuctx,
2621 			  enum event_type_t event_type);
2622 static void
2623 ctx_sched_in(struct perf_event_context *ctx,
2624 	     struct perf_cpu_context *cpuctx,
2625 	     enum event_type_t event_type);
2626 
task_ctx_sched_out(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,enum event_type_t event_type)2627 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2628 			       struct perf_event_context *ctx,
2629 			       enum event_type_t event_type)
2630 {
2631 	if (!cpuctx->task_ctx)
2632 		return;
2633 
2634 	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2635 		return;
2636 
2637 	ctx_sched_out(ctx, cpuctx, event_type);
2638 }
2639 
perf_event_sched_in(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2640 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2641 				struct perf_event_context *ctx)
2642 {
2643 	cpu_ctx_sched_in(cpuctx, EVENT_PINNED);
2644 	if (ctx)
2645 		ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
2646 	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
2647 	if (ctx)
2648 		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
2649 }
2650 
2651 /*
2652  * We want to maintain the following priority of scheduling:
2653  *  - CPU pinned (EVENT_CPU | EVENT_PINNED)
2654  *  - task pinned (EVENT_PINNED)
2655  *  - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2656  *  - task flexible (EVENT_FLEXIBLE).
2657  *
2658  * In order to avoid unscheduling and scheduling back in everything every
2659  * time an event is added, only do it for the groups of equal priority and
2660  * below.
2661  *
2662  * This can be called after a batch operation on task events, in which case
2663  * event_type is a bit mask of the types of events involved. For CPU events,
2664  * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2665  */
ctx_resched(struct perf_cpu_context * cpuctx,struct perf_event_context * task_ctx,enum event_type_t event_type)2666 static void ctx_resched(struct perf_cpu_context *cpuctx,
2667 			struct perf_event_context *task_ctx,
2668 			enum event_type_t event_type)
2669 {
2670 	enum event_type_t ctx_event_type;
2671 	bool cpu_event = !!(event_type & EVENT_CPU);
2672 
2673 	/*
2674 	 * If pinned groups are involved, flexible groups also need to be
2675 	 * scheduled out.
2676 	 */
2677 	if (event_type & EVENT_PINNED)
2678 		event_type |= EVENT_FLEXIBLE;
2679 
2680 	ctx_event_type = event_type & EVENT_ALL;
2681 
2682 	perf_pmu_disable(cpuctx->ctx.pmu);
2683 	if (task_ctx)
2684 		task_ctx_sched_out(cpuctx, task_ctx, event_type);
2685 
2686 	/*
2687 	 * Decide which cpu ctx groups to schedule out based on the types
2688 	 * of events that caused rescheduling:
2689 	 *  - EVENT_CPU: schedule out corresponding groups;
2690 	 *  - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2691 	 *  - otherwise, do nothing more.
2692 	 */
2693 	if (cpu_event)
2694 		cpu_ctx_sched_out(cpuctx, ctx_event_type);
2695 	else if (ctx_event_type & EVENT_PINNED)
2696 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2697 
2698 	perf_event_sched_in(cpuctx, task_ctx);
2699 	perf_pmu_enable(cpuctx->ctx.pmu);
2700 }
2701 
perf_pmu_resched(struct pmu * pmu)2702 void perf_pmu_resched(struct pmu *pmu)
2703 {
2704 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2705 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2706 
2707 	perf_ctx_lock(cpuctx, task_ctx);
2708 	ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2709 	perf_ctx_unlock(cpuctx, task_ctx);
2710 }
2711 
2712 /*
2713  * Cross CPU call to install and enable a performance event
2714  *
2715  * Very similar to remote_function() + event_function() but cannot assume that
2716  * things like ctx->is_active and cpuctx->task_ctx are set.
2717  */
__perf_install_in_context(void * info)2718 static int  __perf_install_in_context(void *info)
2719 {
2720 	struct perf_event *event = info;
2721 	struct perf_event_context *ctx = event->ctx;
2722 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2723 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2724 	bool reprogram = true;
2725 	int ret = 0;
2726 
2727 	raw_spin_lock(&cpuctx->ctx.lock);
2728 	if (ctx->task) {
2729 		raw_spin_lock(&ctx->lock);
2730 		task_ctx = ctx;
2731 
2732 		reprogram = (ctx->task == current);
2733 
2734 		/*
2735 		 * If the task is running, it must be running on this CPU,
2736 		 * otherwise we cannot reprogram things.
2737 		 *
2738 		 * If its not running, we don't care, ctx->lock will
2739 		 * serialize against it becoming runnable.
2740 		 */
2741 		if (task_curr(ctx->task) && !reprogram) {
2742 			ret = -ESRCH;
2743 			goto unlock;
2744 		}
2745 
2746 		WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2747 	} else if (task_ctx) {
2748 		raw_spin_lock(&task_ctx->lock);
2749 	}
2750 
2751 #ifdef CONFIG_CGROUP_PERF
2752 	if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2753 		/*
2754 		 * If the current cgroup doesn't match the event's
2755 		 * cgroup, we should not try to schedule it.
2756 		 */
2757 		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2758 		reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2759 					event->cgrp->css.cgroup);
2760 	}
2761 #endif
2762 
2763 	if (reprogram) {
2764 		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2765 		add_event_to_ctx(event, ctx);
2766 		ctx_resched(cpuctx, task_ctx, get_event_type(event));
2767 	} else {
2768 		add_event_to_ctx(event, ctx);
2769 	}
2770 
2771 unlock:
2772 	perf_ctx_unlock(cpuctx, task_ctx);
2773 
2774 	return ret;
2775 }
2776 
2777 static bool exclusive_event_installable(struct perf_event *event,
2778 					struct perf_event_context *ctx);
2779 
2780 /*
2781  * Attach a performance event to a context.
2782  *
2783  * Very similar to event_function_call, see comment there.
2784  */
2785 static void
perf_install_in_context(struct perf_event_context * ctx,struct perf_event * event,int cpu)2786 perf_install_in_context(struct perf_event_context *ctx,
2787 			struct perf_event *event,
2788 			int cpu)
2789 {
2790 	struct task_struct *task = READ_ONCE(ctx->task);
2791 
2792 	lockdep_assert_held(&ctx->mutex);
2793 
2794 	WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2795 
2796 	if (event->cpu != -1)
2797 		event->cpu = cpu;
2798 
2799 	/*
2800 	 * Ensures that if we can observe event->ctx, both the event and ctx
2801 	 * will be 'complete'. See perf_iterate_sb_cpu().
2802 	 */
2803 	smp_store_release(&event->ctx, ctx);
2804 
2805 	/*
2806 	 * perf_event_attr::disabled events will not run and can be initialized
2807 	 * without IPI. Except when this is the first event for the context, in
2808 	 * that case we need the magic of the IPI to set ctx->is_active.
2809 	 * Similarly, cgroup events for the context also needs the IPI to
2810 	 * manipulate the cgrp_cpuctx_list.
2811 	 *
2812 	 * The IOC_ENABLE that is sure to follow the creation of a disabled
2813 	 * event will issue the IPI and reprogram the hardware.
2814 	 */
2815 	if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2816 	    ctx->nr_events && !is_cgroup_event(event)) {
2817 		raw_spin_lock_irq(&ctx->lock);
2818 		if (ctx->task == TASK_TOMBSTONE) {
2819 			raw_spin_unlock_irq(&ctx->lock);
2820 			return;
2821 		}
2822 		add_event_to_ctx(event, ctx);
2823 		raw_spin_unlock_irq(&ctx->lock);
2824 		return;
2825 	}
2826 
2827 	if (!task) {
2828 		cpu_function_call(cpu, __perf_install_in_context, event);
2829 		return;
2830 	}
2831 
2832 	/*
2833 	 * Should not happen, we validate the ctx is still alive before calling.
2834 	 */
2835 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2836 		return;
2837 
2838 	/*
2839 	 * Installing events is tricky because we cannot rely on ctx->is_active
2840 	 * to be set in case this is the nr_events 0 -> 1 transition.
2841 	 *
2842 	 * Instead we use task_curr(), which tells us if the task is running.
2843 	 * However, since we use task_curr() outside of rq::lock, we can race
2844 	 * against the actual state. This means the result can be wrong.
2845 	 *
2846 	 * If we get a false positive, we retry, this is harmless.
2847 	 *
2848 	 * If we get a false negative, things are complicated. If we are after
2849 	 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2850 	 * value must be correct. If we're before, it doesn't matter since
2851 	 * perf_event_context_sched_in() will program the counter.
2852 	 *
2853 	 * However, this hinges on the remote context switch having observed
2854 	 * our task->perf_event_ctxp[] store, such that it will in fact take
2855 	 * ctx::lock in perf_event_context_sched_in().
2856 	 *
2857 	 * We do this by task_function_call(), if the IPI fails to hit the task
2858 	 * we know any future context switch of task must see the
2859 	 * perf_event_ctpx[] store.
2860 	 */
2861 
2862 	/*
2863 	 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2864 	 * task_cpu() load, such that if the IPI then does not find the task
2865 	 * running, a future context switch of that task must observe the
2866 	 * store.
2867 	 */
2868 	smp_mb();
2869 again:
2870 	if (!task_function_call(task, __perf_install_in_context, event))
2871 		return;
2872 
2873 	raw_spin_lock_irq(&ctx->lock);
2874 	task = ctx->task;
2875 	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2876 		/*
2877 		 * Cannot happen because we already checked above (which also
2878 		 * cannot happen), and we hold ctx->mutex, which serializes us
2879 		 * against perf_event_exit_task_context().
2880 		 */
2881 		raw_spin_unlock_irq(&ctx->lock);
2882 		return;
2883 	}
2884 	/*
2885 	 * If the task is not running, ctx->lock will avoid it becoming so,
2886 	 * thus we can safely install the event.
2887 	 */
2888 	if (task_curr(task)) {
2889 		raw_spin_unlock_irq(&ctx->lock);
2890 		goto again;
2891 	}
2892 	add_event_to_ctx(event, ctx);
2893 	raw_spin_unlock_irq(&ctx->lock);
2894 }
2895 
2896 /*
2897  * Cross CPU call to enable a performance event
2898  */
__perf_event_enable(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2899 static void __perf_event_enable(struct perf_event *event,
2900 				struct perf_cpu_context *cpuctx,
2901 				struct perf_event_context *ctx,
2902 				void *info)
2903 {
2904 	struct perf_event *leader = event->group_leader;
2905 	struct perf_event_context *task_ctx;
2906 
2907 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2908 	    event->state <= PERF_EVENT_STATE_ERROR)
2909 		return;
2910 
2911 	if (ctx->is_active)
2912 		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2913 
2914 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2915 	perf_cgroup_event_enable(event, ctx);
2916 
2917 	if (!ctx->is_active)
2918 		return;
2919 
2920 	if (!event_filter_match(event)) {
2921 		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2922 		return;
2923 	}
2924 
2925 	/*
2926 	 * If the event is in a group and isn't the group leader,
2927 	 * then don't put it on unless the group is on.
2928 	 */
2929 	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2930 		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2931 		return;
2932 	}
2933 
2934 	task_ctx = cpuctx->task_ctx;
2935 	if (ctx->task)
2936 		WARN_ON_ONCE(task_ctx != ctx);
2937 
2938 	ctx_resched(cpuctx, task_ctx, get_event_type(event));
2939 }
2940 
2941 /*
2942  * Enable an event.
2943  *
2944  * If event->ctx is a cloned context, callers must make sure that
2945  * every task struct that event->ctx->task could possibly point to
2946  * remains valid.  This condition is satisfied when called through
2947  * perf_event_for_each_child or perf_event_for_each as described
2948  * for perf_event_disable.
2949  */
_perf_event_enable(struct perf_event * event)2950 static void _perf_event_enable(struct perf_event *event)
2951 {
2952 	struct perf_event_context *ctx = event->ctx;
2953 
2954 	raw_spin_lock_irq(&ctx->lock);
2955 	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2956 	    event->state <  PERF_EVENT_STATE_ERROR) {
2957 out:
2958 		raw_spin_unlock_irq(&ctx->lock);
2959 		return;
2960 	}
2961 
2962 	/*
2963 	 * If the event is in error state, clear that first.
2964 	 *
2965 	 * That way, if we see the event in error state below, we know that it
2966 	 * has gone back into error state, as distinct from the task having
2967 	 * been scheduled away before the cross-call arrived.
2968 	 */
2969 	if (event->state == PERF_EVENT_STATE_ERROR) {
2970 		/*
2971 		 * Detached SIBLING events cannot leave ERROR state.
2972 		 */
2973 		if (event->event_caps & PERF_EV_CAP_SIBLING &&
2974 		    event->group_leader == event)
2975 			goto out;
2976 
2977 		event->state = PERF_EVENT_STATE_OFF;
2978 	}
2979 	raw_spin_unlock_irq(&ctx->lock);
2980 
2981 	event_function_call(event, __perf_event_enable, NULL);
2982 }
2983 
2984 /*
2985  * See perf_event_disable();
2986  */
perf_event_enable(struct perf_event * event)2987 void perf_event_enable(struct perf_event *event)
2988 {
2989 	struct perf_event_context *ctx;
2990 
2991 	ctx = perf_event_ctx_lock(event);
2992 	_perf_event_enable(event);
2993 	perf_event_ctx_unlock(event, ctx);
2994 }
2995 EXPORT_SYMBOL_GPL(perf_event_enable);
2996 
2997 struct stop_event_data {
2998 	struct perf_event	*event;
2999 	unsigned int		restart;
3000 };
3001 
__perf_event_stop(void * info)3002 static int __perf_event_stop(void *info)
3003 {
3004 	struct stop_event_data *sd = info;
3005 	struct perf_event *event = sd->event;
3006 
3007 	/* if it's already INACTIVE, do nothing */
3008 	if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3009 		return 0;
3010 
3011 	/* matches smp_wmb() in event_sched_in() */
3012 	smp_rmb();
3013 
3014 	/*
3015 	 * There is a window with interrupts enabled before we get here,
3016 	 * so we need to check again lest we try to stop another CPU's event.
3017 	 */
3018 	if (READ_ONCE(event->oncpu) != smp_processor_id())
3019 		return -EAGAIN;
3020 
3021 	event->pmu->stop(event, PERF_EF_UPDATE);
3022 
3023 	/*
3024 	 * May race with the actual stop (through perf_pmu_output_stop()),
3025 	 * but it is only used for events with AUX ring buffer, and such
3026 	 * events will refuse to restart because of rb::aux_mmap_count==0,
3027 	 * see comments in perf_aux_output_begin().
3028 	 *
3029 	 * Since this is happening on an event-local CPU, no trace is lost
3030 	 * while restarting.
3031 	 */
3032 	if (sd->restart)
3033 		event->pmu->start(event, 0);
3034 
3035 	return 0;
3036 }
3037 
perf_event_stop(struct perf_event * event,int restart)3038 static int perf_event_stop(struct perf_event *event, int restart)
3039 {
3040 	struct stop_event_data sd = {
3041 		.event		= event,
3042 		.restart	= restart,
3043 	};
3044 	int ret = 0;
3045 
3046 	do {
3047 		if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3048 			return 0;
3049 
3050 		/* matches smp_wmb() in event_sched_in() */
3051 		smp_rmb();
3052 
3053 		/*
3054 		 * We only want to restart ACTIVE events, so if the event goes
3055 		 * inactive here (event->oncpu==-1), there's nothing more to do;
3056 		 * fall through with ret==-ENXIO.
3057 		 */
3058 		ret = cpu_function_call(READ_ONCE(event->oncpu),
3059 					__perf_event_stop, &sd);
3060 	} while (ret == -EAGAIN);
3061 
3062 	return ret;
3063 }
3064 
3065 /*
3066  * In order to contain the amount of racy and tricky in the address filter
3067  * configuration management, it is a two part process:
3068  *
3069  * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3070  *      we update the addresses of corresponding vmas in
3071  *	event::addr_filter_ranges array and bump the event::addr_filters_gen;
3072  * (p2) when an event is scheduled in (pmu::add), it calls
3073  *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3074  *      if the generation has changed since the previous call.
3075  *
3076  * If (p1) happens while the event is active, we restart it to force (p2).
3077  *
3078  * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3079  *     pre-existing mappings, called once when new filters arrive via SET_FILTER
3080  *     ioctl;
3081  * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3082  *     registered mapping, called for every new mmap(), with mm::mmap_lock down
3083  *     for reading;
3084  * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3085  *     of exec.
3086  */
perf_event_addr_filters_sync(struct perf_event * event)3087 void perf_event_addr_filters_sync(struct perf_event *event)
3088 {
3089 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3090 
3091 	if (!has_addr_filter(event))
3092 		return;
3093 
3094 	raw_spin_lock(&ifh->lock);
3095 	if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3096 		event->pmu->addr_filters_sync(event);
3097 		event->hw.addr_filters_gen = event->addr_filters_gen;
3098 	}
3099 	raw_spin_unlock(&ifh->lock);
3100 }
3101 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3102 
_perf_event_refresh(struct perf_event * event,int refresh)3103 static int _perf_event_refresh(struct perf_event *event, int refresh)
3104 {
3105 	/*
3106 	 * not supported on inherited events
3107 	 */
3108 	if (event->attr.inherit || !is_sampling_event(event))
3109 		return -EINVAL;
3110 
3111 	atomic_add(refresh, &event->event_limit);
3112 	_perf_event_enable(event);
3113 
3114 	return 0;
3115 }
3116 
3117 /*
3118  * See perf_event_disable()
3119  */
perf_event_refresh(struct perf_event * event,int refresh)3120 int perf_event_refresh(struct perf_event *event, int refresh)
3121 {
3122 	struct perf_event_context *ctx;
3123 	int ret;
3124 
3125 	ctx = perf_event_ctx_lock(event);
3126 	ret = _perf_event_refresh(event, refresh);
3127 	perf_event_ctx_unlock(event, ctx);
3128 
3129 	return ret;
3130 }
3131 EXPORT_SYMBOL_GPL(perf_event_refresh);
3132 
perf_event_modify_breakpoint(struct perf_event * bp,struct perf_event_attr * attr)3133 static int perf_event_modify_breakpoint(struct perf_event *bp,
3134 					 struct perf_event_attr *attr)
3135 {
3136 	int err;
3137 
3138 	_perf_event_disable(bp);
3139 
3140 	err = modify_user_hw_breakpoint_check(bp, attr, true);
3141 
3142 	if (!bp->attr.disabled)
3143 		_perf_event_enable(bp);
3144 
3145 	return err;
3146 }
3147 
3148 /*
3149  * Copy event-type-independent attributes that may be modified.
3150  */
perf_event_modify_copy_attr(struct perf_event_attr * to,const struct perf_event_attr * from)3151 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3152 					const struct perf_event_attr *from)
3153 {
3154 	to->sig_data = from->sig_data;
3155 }
3156 
perf_event_modify_attr(struct perf_event * event,struct perf_event_attr * attr)3157 static int perf_event_modify_attr(struct perf_event *event,
3158 				  struct perf_event_attr *attr)
3159 {
3160 	int (*func)(struct perf_event *, struct perf_event_attr *);
3161 	struct perf_event *child;
3162 	int err;
3163 
3164 	if (event->attr.type != attr->type)
3165 		return -EINVAL;
3166 
3167 	switch (event->attr.type) {
3168 	case PERF_TYPE_BREAKPOINT:
3169 		func = perf_event_modify_breakpoint;
3170 		break;
3171 	default:
3172 		/* Place holder for future additions. */
3173 		return -EOPNOTSUPP;
3174 	}
3175 
3176 	WARN_ON_ONCE(event->ctx->parent_ctx);
3177 
3178 	mutex_lock(&event->child_mutex);
3179 	/*
3180 	 * Event-type-independent attributes must be copied before event-type
3181 	 * modification, which will validate that final attributes match the
3182 	 * source attributes after all relevant attributes have been copied.
3183 	 */
3184 	perf_event_modify_copy_attr(&event->attr, attr);
3185 	err = func(event, attr);
3186 	if (err)
3187 		goto out;
3188 	list_for_each_entry(child, &event->child_list, child_list) {
3189 		perf_event_modify_copy_attr(&child->attr, attr);
3190 		err = func(child, attr);
3191 		if (err)
3192 			goto out;
3193 	}
3194 out:
3195 	mutex_unlock(&event->child_mutex);
3196 	return err;
3197 }
3198 
ctx_sched_out(struct perf_event_context * ctx,struct perf_cpu_context * cpuctx,enum event_type_t event_type)3199 static void ctx_sched_out(struct perf_event_context *ctx,
3200 			  struct perf_cpu_context *cpuctx,
3201 			  enum event_type_t event_type)
3202 {
3203 	struct perf_event *event, *tmp;
3204 	int is_active = ctx->is_active;
3205 
3206 	lockdep_assert_held(&ctx->lock);
3207 
3208 	if (likely(!ctx->nr_events)) {
3209 		/*
3210 		 * See __perf_remove_from_context().
3211 		 */
3212 		WARN_ON_ONCE(ctx->is_active);
3213 		if (ctx->task)
3214 			WARN_ON_ONCE(cpuctx->task_ctx);
3215 		return;
3216 	}
3217 
3218 	/*
3219 	 * Always update time if it was set; not only when it changes.
3220 	 * Otherwise we can 'forget' to update time for any but the last
3221 	 * context we sched out. For example:
3222 	 *
3223 	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3224 	 *   ctx_sched_out(.event_type = EVENT_PINNED)
3225 	 *
3226 	 * would only update time for the pinned events.
3227 	 */
3228 	if (is_active & EVENT_TIME) {
3229 		/* update (and stop) ctx time */
3230 		update_context_time(ctx);
3231 		update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3232 		/*
3233 		 * CPU-release for the below ->is_active store,
3234 		 * see __load_acquire() in perf_event_time_now()
3235 		 */
3236 		barrier();
3237 	}
3238 
3239 	ctx->is_active &= ~event_type;
3240 	if (!(ctx->is_active & EVENT_ALL))
3241 		ctx->is_active = 0;
3242 
3243 	if (ctx->task) {
3244 		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3245 		if (!ctx->is_active)
3246 			cpuctx->task_ctx = NULL;
3247 	}
3248 
3249 	is_active ^= ctx->is_active; /* changed bits */
3250 
3251 	if (!ctx->nr_active || !(is_active & EVENT_ALL))
3252 		return;
3253 
3254 	perf_pmu_disable(ctx->pmu);
3255 	if (is_active & EVENT_PINNED) {
3256 		list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3257 			group_sched_out(event, cpuctx, ctx);
3258 	}
3259 
3260 	if (is_active & EVENT_FLEXIBLE) {
3261 		list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3262 			group_sched_out(event, cpuctx, ctx);
3263 
3264 		/*
3265 		 * Since we cleared EVENT_FLEXIBLE, also clear
3266 		 * rotate_necessary, is will be reset by
3267 		 * ctx_flexible_sched_in() when needed.
3268 		 */
3269 		ctx->rotate_necessary = 0;
3270 	}
3271 	perf_pmu_enable(ctx->pmu);
3272 }
3273 
3274 /*
3275  * Test whether two contexts are equivalent, i.e. whether they have both been
3276  * cloned from the same version of the same context.
3277  *
3278  * Equivalence is measured using a generation number in the context that is
3279  * incremented on each modification to it; see unclone_ctx(), list_add_event()
3280  * and list_del_event().
3281  */
context_equiv(struct perf_event_context * ctx1,struct perf_event_context * ctx2)3282 static int context_equiv(struct perf_event_context *ctx1,
3283 			 struct perf_event_context *ctx2)
3284 {
3285 	lockdep_assert_held(&ctx1->lock);
3286 	lockdep_assert_held(&ctx2->lock);
3287 
3288 	/* Pinning disables the swap optimization */
3289 	if (ctx1->pin_count || ctx2->pin_count)
3290 		return 0;
3291 
3292 	/* If ctx1 is the parent of ctx2 */
3293 	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3294 		return 1;
3295 
3296 	/* If ctx2 is the parent of ctx1 */
3297 	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3298 		return 1;
3299 
3300 	/*
3301 	 * If ctx1 and ctx2 have the same parent; we flatten the parent
3302 	 * hierarchy, see perf_event_init_context().
3303 	 */
3304 	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3305 			ctx1->parent_gen == ctx2->parent_gen)
3306 		return 1;
3307 
3308 	/* Unmatched */
3309 	return 0;
3310 }
3311 
__perf_event_sync_stat(struct perf_event * event,struct perf_event * next_event)3312 static void __perf_event_sync_stat(struct perf_event *event,
3313 				     struct perf_event *next_event)
3314 {
3315 	u64 value;
3316 
3317 	if (!event->attr.inherit_stat)
3318 		return;
3319 
3320 	/*
3321 	 * Update the event value, we cannot use perf_event_read()
3322 	 * because we're in the middle of a context switch and have IRQs
3323 	 * disabled, which upsets smp_call_function_single(), however
3324 	 * we know the event must be on the current CPU, therefore we
3325 	 * don't need to use it.
3326 	 */
3327 	if (event->state == PERF_EVENT_STATE_ACTIVE)
3328 		event->pmu->read(event);
3329 
3330 	perf_event_update_time(event);
3331 
3332 	/*
3333 	 * In order to keep per-task stats reliable we need to flip the event
3334 	 * values when we flip the contexts.
3335 	 */
3336 	value = local64_read(&next_event->count);
3337 	value = local64_xchg(&event->count, value);
3338 	local64_set(&next_event->count, value);
3339 
3340 	swap(event->total_time_enabled, next_event->total_time_enabled);
3341 	swap(event->total_time_running, next_event->total_time_running);
3342 
3343 	/*
3344 	 * Since we swizzled the values, update the user visible data too.
3345 	 */
3346 	perf_event_update_userpage(event);
3347 	perf_event_update_userpage(next_event);
3348 }
3349 
perf_event_sync_stat(struct perf_event_context * ctx,struct perf_event_context * next_ctx)3350 static void perf_event_sync_stat(struct perf_event_context *ctx,
3351 				   struct perf_event_context *next_ctx)
3352 {
3353 	struct perf_event *event, *next_event;
3354 
3355 	if (!ctx->nr_stat)
3356 		return;
3357 
3358 	update_context_time(ctx);
3359 
3360 	event = list_first_entry(&ctx->event_list,
3361 				   struct perf_event, event_entry);
3362 
3363 	next_event = list_first_entry(&next_ctx->event_list,
3364 					struct perf_event, event_entry);
3365 
3366 	while (&event->event_entry != &ctx->event_list &&
3367 	       &next_event->event_entry != &next_ctx->event_list) {
3368 
3369 		__perf_event_sync_stat(event, next_event);
3370 
3371 		event = list_next_entry(event, event_entry);
3372 		next_event = list_next_entry(next_event, event_entry);
3373 	}
3374 }
3375 
perf_event_context_sched_out(struct task_struct * task,int ctxn,struct task_struct * next)3376 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3377 					 struct task_struct *next)
3378 {
3379 	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3380 	struct perf_event_context *next_ctx;
3381 	struct perf_event_context *parent, *next_parent;
3382 	struct perf_cpu_context *cpuctx;
3383 	int do_switch = 1;
3384 	struct pmu *pmu;
3385 
3386 	if (likely(!ctx))
3387 		return;
3388 
3389 	pmu = ctx->pmu;
3390 	cpuctx = __get_cpu_context(ctx);
3391 	if (!cpuctx->task_ctx)
3392 		return;
3393 
3394 	rcu_read_lock();
3395 	next_ctx = next->perf_event_ctxp[ctxn];
3396 	if (!next_ctx)
3397 		goto unlock;
3398 
3399 	parent = rcu_dereference(ctx->parent_ctx);
3400 	next_parent = rcu_dereference(next_ctx->parent_ctx);
3401 
3402 	/* If neither context have a parent context; they cannot be clones. */
3403 	if (!parent && !next_parent)
3404 		goto unlock;
3405 
3406 	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3407 		/*
3408 		 * Looks like the two contexts are clones, so we might be
3409 		 * able to optimize the context switch.  We lock both
3410 		 * contexts and check that they are clones under the
3411 		 * lock (including re-checking that neither has been
3412 		 * uncloned in the meantime).  It doesn't matter which
3413 		 * order we take the locks because no other cpu could
3414 		 * be trying to lock both of these tasks.
3415 		 */
3416 		raw_spin_lock(&ctx->lock);
3417 		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3418 		if (context_equiv(ctx, next_ctx)) {
3419 
3420 			WRITE_ONCE(ctx->task, next);
3421 			WRITE_ONCE(next_ctx->task, task);
3422 
3423 			perf_pmu_disable(pmu);
3424 
3425 			if (cpuctx->sched_cb_usage && pmu->sched_task)
3426 				pmu->sched_task(ctx, false);
3427 
3428 			/*
3429 			 * PMU specific parts of task perf context can require
3430 			 * additional synchronization. As an example of such
3431 			 * synchronization see implementation details of Intel
3432 			 * LBR call stack data profiling;
3433 			 */
3434 			if (pmu->swap_task_ctx)
3435 				pmu->swap_task_ctx(ctx, next_ctx);
3436 			else
3437 				swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3438 
3439 			perf_pmu_enable(pmu);
3440 
3441 			/*
3442 			 * RCU_INIT_POINTER here is safe because we've not
3443 			 * modified the ctx and the above modification of
3444 			 * ctx->task and ctx->task_ctx_data are immaterial
3445 			 * since those values are always verified under
3446 			 * ctx->lock which we're now holding.
3447 			 */
3448 			RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3449 			RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3450 
3451 			do_switch = 0;
3452 
3453 			perf_event_sync_stat(ctx, next_ctx);
3454 		}
3455 		raw_spin_unlock(&next_ctx->lock);
3456 		raw_spin_unlock(&ctx->lock);
3457 	}
3458 unlock:
3459 	rcu_read_unlock();
3460 
3461 	if (do_switch) {
3462 		raw_spin_lock(&ctx->lock);
3463 		perf_pmu_disable(pmu);
3464 
3465 		if (cpuctx->sched_cb_usage && pmu->sched_task)
3466 			pmu->sched_task(ctx, false);
3467 		task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3468 
3469 		perf_pmu_enable(pmu);
3470 		raw_spin_unlock(&ctx->lock);
3471 	}
3472 }
3473 
3474 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3475 
perf_sched_cb_dec(struct pmu * pmu)3476 void perf_sched_cb_dec(struct pmu *pmu)
3477 {
3478 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3479 
3480 	this_cpu_dec(perf_sched_cb_usages);
3481 
3482 	if (!--cpuctx->sched_cb_usage)
3483 		list_del(&cpuctx->sched_cb_entry);
3484 }
3485 
3486 
perf_sched_cb_inc(struct pmu * pmu)3487 void perf_sched_cb_inc(struct pmu *pmu)
3488 {
3489 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3490 
3491 	if (!cpuctx->sched_cb_usage++)
3492 		list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3493 
3494 	this_cpu_inc(perf_sched_cb_usages);
3495 }
3496 
3497 /*
3498  * This function provides the context switch callback to the lower code
3499  * layer. It is invoked ONLY when the context switch callback is enabled.
3500  *
3501  * This callback is relevant even to per-cpu events; for example multi event
3502  * PEBS requires this to provide PID/TID information. This requires we flush
3503  * all queued PEBS records before we context switch to a new task.
3504  */
__perf_pmu_sched_task(struct perf_cpu_context * cpuctx,bool sched_in)3505 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3506 {
3507 	struct pmu *pmu;
3508 
3509 	pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3510 
3511 	if (WARN_ON_ONCE(!pmu->sched_task))
3512 		return;
3513 
3514 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3515 	perf_pmu_disable(pmu);
3516 
3517 	pmu->sched_task(cpuctx->task_ctx, sched_in);
3518 
3519 	perf_pmu_enable(pmu);
3520 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3521 }
3522 
perf_pmu_sched_task(struct task_struct * prev,struct task_struct * next,bool sched_in)3523 static void perf_pmu_sched_task(struct task_struct *prev,
3524 				struct task_struct *next,
3525 				bool sched_in)
3526 {
3527 	struct perf_cpu_context *cpuctx;
3528 
3529 	if (prev == next)
3530 		return;
3531 
3532 	list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3533 		/* will be handled in perf_event_context_sched_in/out */
3534 		if (cpuctx->task_ctx)
3535 			continue;
3536 
3537 		__perf_pmu_sched_task(cpuctx, sched_in);
3538 	}
3539 }
3540 
3541 static void perf_event_switch(struct task_struct *task,
3542 			      struct task_struct *next_prev, bool sched_in);
3543 
3544 #define for_each_task_context_nr(ctxn)					\
3545 	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3546 
3547 /*
3548  * Called from scheduler to remove the events of the current task,
3549  * with interrupts disabled.
3550  *
3551  * We stop each event and update the event value in event->count.
3552  *
3553  * This does not protect us against NMI, but disable()
3554  * sets the disabled bit in the control field of event _before_
3555  * accessing the event control register. If a NMI hits, then it will
3556  * not restart the event.
3557  */
__perf_event_task_sched_out(struct task_struct * task,struct task_struct * next)3558 void __perf_event_task_sched_out(struct task_struct *task,
3559 				 struct task_struct *next)
3560 {
3561 	int ctxn;
3562 
3563 	if (__this_cpu_read(perf_sched_cb_usages))
3564 		perf_pmu_sched_task(task, next, false);
3565 
3566 	if (atomic_read(&nr_switch_events))
3567 		perf_event_switch(task, next, false);
3568 
3569 	for_each_task_context_nr(ctxn)
3570 		perf_event_context_sched_out(task, ctxn, next);
3571 
3572 	/*
3573 	 * if cgroup events exist on this CPU, then we need
3574 	 * to check if we have to switch out PMU state.
3575 	 * cgroup event are system-wide mode only
3576 	 */
3577 	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3578 		perf_cgroup_switch(next);
3579 }
3580 
3581 /*
3582  * Called with IRQs disabled
3583  */
cpu_ctx_sched_out(struct perf_cpu_context * cpuctx,enum event_type_t event_type)3584 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3585 			      enum event_type_t event_type)
3586 {
3587 	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3588 }
3589 
perf_less_group_idx(const void * l,const void * r)3590 static bool perf_less_group_idx(const void *l, const void *r)
3591 {
3592 	const struct perf_event *le = *(const struct perf_event **)l;
3593 	const struct perf_event *re = *(const struct perf_event **)r;
3594 
3595 	return le->group_index < re->group_index;
3596 }
3597 
swap_ptr(void * l,void * r)3598 static void swap_ptr(void *l, void *r)
3599 {
3600 	void **lp = l, **rp = r;
3601 
3602 	swap(*lp, *rp);
3603 }
3604 
3605 static const struct min_heap_callbacks perf_min_heap = {
3606 	.elem_size = sizeof(struct perf_event *),
3607 	.less = perf_less_group_idx,
3608 	.swp = swap_ptr,
3609 };
3610 
__heap_add(struct min_heap * heap,struct perf_event * event)3611 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3612 {
3613 	struct perf_event **itrs = heap->data;
3614 
3615 	if (event) {
3616 		itrs[heap->nr] = event;
3617 		heap->nr++;
3618 	}
3619 }
3620 
visit_groups_merge(struct perf_cpu_context * cpuctx,struct perf_event_groups * groups,int cpu,int (* func)(struct perf_event *,void *),void * data)3621 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3622 				struct perf_event_groups *groups, int cpu,
3623 				int (*func)(struct perf_event *, void *),
3624 				void *data)
3625 {
3626 #ifdef CONFIG_CGROUP_PERF
3627 	struct cgroup_subsys_state *css = NULL;
3628 #endif
3629 	/* Space for per CPU and/or any CPU event iterators. */
3630 	struct perf_event *itrs[2];
3631 	struct min_heap event_heap;
3632 	struct perf_event **evt;
3633 	int ret;
3634 
3635 	if (cpuctx) {
3636 		event_heap = (struct min_heap){
3637 			.data = cpuctx->heap,
3638 			.nr = 0,
3639 			.size = cpuctx->heap_size,
3640 		};
3641 
3642 		lockdep_assert_held(&cpuctx->ctx.lock);
3643 
3644 #ifdef CONFIG_CGROUP_PERF
3645 		if (cpuctx->cgrp)
3646 			css = &cpuctx->cgrp->css;
3647 #endif
3648 	} else {
3649 		event_heap = (struct min_heap){
3650 			.data = itrs,
3651 			.nr = 0,
3652 			.size = ARRAY_SIZE(itrs),
3653 		};
3654 		/* Events not within a CPU context may be on any CPU. */
3655 		__heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3656 	}
3657 	evt = event_heap.data;
3658 
3659 	__heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3660 
3661 #ifdef CONFIG_CGROUP_PERF
3662 	for (; css; css = css->parent)
3663 		__heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3664 #endif
3665 
3666 	min_heapify_all(&event_heap, &perf_min_heap);
3667 
3668 	while (event_heap.nr) {
3669 		ret = func(*evt, data);
3670 		if (ret)
3671 			return ret;
3672 
3673 		*evt = perf_event_groups_next(*evt);
3674 		if (*evt)
3675 			min_heapify(&event_heap, 0, &perf_min_heap);
3676 		else
3677 			min_heap_pop(&event_heap, &perf_min_heap);
3678 	}
3679 
3680 	return 0;
3681 }
3682 
3683 /*
3684  * Because the userpage is strictly per-event (there is no concept of context,
3685  * so there cannot be a context indirection), every userpage must be updated
3686  * when context time starts :-(
3687  *
3688  * IOW, we must not miss EVENT_TIME edges.
3689  */
event_update_userpage(struct perf_event * event)3690 static inline bool event_update_userpage(struct perf_event *event)
3691 {
3692 	if (likely(!atomic_read(&event->mmap_count)))
3693 		return false;
3694 
3695 	perf_event_update_time(event);
3696 	perf_event_update_userpage(event);
3697 
3698 	return true;
3699 }
3700 
group_update_userpage(struct perf_event * group_event)3701 static inline void group_update_userpage(struct perf_event *group_event)
3702 {
3703 	struct perf_event *event;
3704 
3705 	if (!event_update_userpage(group_event))
3706 		return;
3707 
3708 	for_each_sibling_event(event, group_event)
3709 		event_update_userpage(event);
3710 }
3711 
merge_sched_in(struct perf_event * event,void * data)3712 static int merge_sched_in(struct perf_event *event, void *data)
3713 {
3714 	struct perf_event_context *ctx = event->ctx;
3715 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3716 	int *can_add_hw = data;
3717 
3718 	if (event->state <= PERF_EVENT_STATE_OFF)
3719 		return 0;
3720 
3721 	if (!event_filter_match(event))
3722 		return 0;
3723 
3724 	if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3725 		if (!group_sched_in(event, cpuctx, ctx))
3726 			list_add_tail(&event->active_list, get_event_list(event));
3727 	}
3728 
3729 	if (event->state == PERF_EVENT_STATE_INACTIVE) {
3730 		*can_add_hw = 0;
3731 		if (event->attr.pinned) {
3732 			perf_cgroup_event_disable(event, ctx);
3733 			perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3734 		} else {
3735 			ctx->rotate_necessary = 1;
3736 			perf_mux_hrtimer_restart(cpuctx);
3737 			group_update_userpage(event);
3738 		}
3739 	}
3740 
3741 	return 0;
3742 }
3743 
3744 static void
ctx_pinned_sched_in(struct perf_event_context * ctx,struct perf_cpu_context * cpuctx)3745 ctx_pinned_sched_in(struct perf_event_context *ctx,
3746 		    struct perf_cpu_context *cpuctx)
3747 {
3748 	int can_add_hw = 1;
3749 
3750 	if (ctx != &cpuctx->ctx)
3751 		cpuctx = NULL;
3752 
3753 	visit_groups_merge(cpuctx, &ctx->pinned_groups,
3754 			   smp_processor_id(),
3755 			   merge_sched_in, &can_add_hw);
3756 }
3757 
3758 static void
ctx_flexible_sched_in(struct perf_event_context * ctx,struct perf_cpu_context * cpuctx)3759 ctx_flexible_sched_in(struct perf_event_context *ctx,
3760 		      struct perf_cpu_context *cpuctx)
3761 {
3762 	int can_add_hw = 1;
3763 
3764 	if (ctx != &cpuctx->ctx)
3765 		cpuctx = NULL;
3766 
3767 	visit_groups_merge(cpuctx, &ctx->flexible_groups,
3768 			   smp_processor_id(),
3769 			   merge_sched_in, &can_add_hw);
3770 }
3771 
3772 static void
ctx_sched_in(struct perf_event_context * ctx,struct perf_cpu_context * cpuctx,enum event_type_t event_type)3773 ctx_sched_in(struct perf_event_context *ctx,
3774 	     struct perf_cpu_context *cpuctx,
3775 	     enum event_type_t event_type)
3776 {
3777 	int is_active = ctx->is_active;
3778 
3779 	lockdep_assert_held(&ctx->lock);
3780 
3781 	if (likely(!ctx->nr_events))
3782 		return;
3783 
3784 	if (is_active ^ EVENT_TIME) {
3785 		/* start ctx time */
3786 		__update_context_time(ctx, false);
3787 		perf_cgroup_set_timestamp(cpuctx);
3788 		/*
3789 		 * CPU-release for the below ->is_active store,
3790 		 * see __load_acquire() in perf_event_time_now()
3791 		 */
3792 		barrier();
3793 	}
3794 
3795 	ctx->is_active |= (event_type | EVENT_TIME);
3796 	if (ctx->task) {
3797 		if (!is_active)
3798 			cpuctx->task_ctx = ctx;
3799 		else
3800 			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3801 	}
3802 
3803 	is_active ^= ctx->is_active; /* changed bits */
3804 
3805 	/*
3806 	 * First go through the list and put on any pinned groups
3807 	 * in order to give them the best chance of going on.
3808 	 */
3809 	if (is_active & EVENT_PINNED)
3810 		ctx_pinned_sched_in(ctx, cpuctx);
3811 
3812 	/* Then walk through the lower prio flexible groups */
3813 	if (is_active & EVENT_FLEXIBLE)
3814 		ctx_flexible_sched_in(ctx, cpuctx);
3815 }
3816 
cpu_ctx_sched_in(struct perf_cpu_context * cpuctx,enum event_type_t event_type)3817 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3818 			     enum event_type_t event_type)
3819 {
3820 	struct perf_event_context *ctx = &cpuctx->ctx;
3821 
3822 	ctx_sched_in(ctx, cpuctx, event_type);
3823 }
3824 
perf_event_context_sched_in(struct perf_event_context * ctx,struct task_struct * task)3825 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3826 					struct task_struct *task)
3827 {
3828 	struct perf_cpu_context *cpuctx;
3829 	struct pmu *pmu;
3830 
3831 	cpuctx = __get_cpu_context(ctx);
3832 
3833 	/*
3834 	 * HACK: for HETEROGENEOUS the task context might have switched to a
3835 	 * different PMU, force (re)set the context,
3836 	 */
3837 	pmu = ctx->pmu = cpuctx->ctx.pmu;
3838 
3839 	if (cpuctx->task_ctx == ctx) {
3840 		if (cpuctx->sched_cb_usage)
3841 			__perf_pmu_sched_task(cpuctx, true);
3842 		return;
3843 	}
3844 
3845 	perf_ctx_lock(cpuctx, ctx);
3846 	/*
3847 	 * We must check ctx->nr_events while holding ctx->lock, such
3848 	 * that we serialize against perf_install_in_context().
3849 	 */
3850 	if (!ctx->nr_events)
3851 		goto unlock;
3852 
3853 	perf_pmu_disable(pmu);
3854 	/*
3855 	 * We want to keep the following priority order:
3856 	 * cpu pinned (that don't need to move), task pinned,
3857 	 * cpu flexible, task flexible.
3858 	 *
3859 	 * However, if task's ctx is not carrying any pinned
3860 	 * events, no need to flip the cpuctx's events around.
3861 	 */
3862 	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3863 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3864 	perf_event_sched_in(cpuctx, ctx);
3865 
3866 	if (cpuctx->sched_cb_usage && pmu->sched_task)
3867 		pmu->sched_task(cpuctx->task_ctx, true);
3868 
3869 	perf_pmu_enable(pmu);
3870 
3871 unlock:
3872 	perf_ctx_unlock(cpuctx, ctx);
3873 }
3874 
3875 /*
3876  * Called from scheduler to add the events of the current task
3877  * with interrupts disabled.
3878  *
3879  * We restore the event value and then enable it.
3880  *
3881  * This does not protect us against NMI, but enable()
3882  * sets the enabled bit in the control field of event _before_
3883  * accessing the event control register. If a NMI hits, then it will
3884  * keep the event running.
3885  */
__perf_event_task_sched_in(struct task_struct * prev,struct task_struct * task)3886 void __perf_event_task_sched_in(struct task_struct *prev,
3887 				struct task_struct *task)
3888 {
3889 	struct perf_event_context *ctx;
3890 	int ctxn;
3891 
3892 	for_each_task_context_nr(ctxn) {
3893 		ctx = task->perf_event_ctxp[ctxn];
3894 		if (likely(!ctx))
3895 			continue;
3896 
3897 		perf_event_context_sched_in(ctx, task);
3898 	}
3899 
3900 	if (atomic_read(&nr_switch_events))
3901 		perf_event_switch(task, prev, true);
3902 
3903 	if (__this_cpu_read(perf_sched_cb_usages))
3904 		perf_pmu_sched_task(prev, task, true);
3905 }
3906 
perf_calculate_period(struct perf_event * event,u64 nsec,u64 count)3907 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3908 {
3909 	u64 frequency = event->attr.sample_freq;
3910 	u64 sec = NSEC_PER_SEC;
3911 	u64 divisor, dividend;
3912 
3913 	int count_fls, nsec_fls, frequency_fls, sec_fls;
3914 
3915 	count_fls = fls64(count);
3916 	nsec_fls = fls64(nsec);
3917 	frequency_fls = fls64(frequency);
3918 	sec_fls = 30;
3919 
3920 	/*
3921 	 * We got @count in @nsec, with a target of sample_freq HZ
3922 	 * the target period becomes:
3923 	 *
3924 	 *             @count * 10^9
3925 	 * period = -------------------
3926 	 *          @nsec * sample_freq
3927 	 *
3928 	 */
3929 
3930 	/*
3931 	 * Reduce accuracy by one bit such that @a and @b converge
3932 	 * to a similar magnitude.
3933 	 */
3934 #define REDUCE_FLS(a, b)		\
3935 do {					\
3936 	if (a##_fls > b##_fls) {	\
3937 		a >>= 1;		\
3938 		a##_fls--;		\
3939 	} else {			\
3940 		b >>= 1;		\
3941 		b##_fls--;		\
3942 	}				\
3943 } while (0)
3944 
3945 	/*
3946 	 * Reduce accuracy until either term fits in a u64, then proceed with
3947 	 * the other, so that finally we can do a u64/u64 division.
3948 	 */
3949 	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3950 		REDUCE_FLS(nsec, frequency);
3951 		REDUCE_FLS(sec, count);
3952 	}
3953 
3954 	if (count_fls + sec_fls > 64) {
3955 		divisor = nsec * frequency;
3956 
3957 		while (count_fls + sec_fls > 64) {
3958 			REDUCE_FLS(count, sec);
3959 			divisor >>= 1;
3960 		}
3961 
3962 		dividend = count * sec;
3963 	} else {
3964 		dividend = count * sec;
3965 
3966 		while (nsec_fls + frequency_fls > 64) {
3967 			REDUCE_FLS(nsec, frequency);
3968 			dividend >>= 1;
3969 		}
3970 
3971 		divisor = nsec * frequency;
3972 	}
3973 
3974 	if (!divisor)
3975 		return dividend;
3976 
3977 	return div64_u64(dividend, divisor);
3978 }
3979 
3980 static DEFINE_PER_CPU(int, perf_throttled_count);
3981 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3982 
perf_adjust_period(struct perf_event * event,u64 nsec,u64 count,bool disable)3983 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3984 {
3985 	struct hw_perf_event *hwc = &event->hw;
3986 	s64 period, sample_period;
3987 	s64 delta;
3988 
3989 	period = perf_calculate_period(event, nsec, count);
3990 
3991 	delta = (s64)(period - hwc->sample_period);
3992 	delta = (delta + 7) / 8; /* low pass filter */
3993 
3994 	sample_period = hwc->sample_period + delta;
3995 
3996 	if (!sample_period)
3997 		sample_period = 1;
3998 
3999 	hwc->sample_period = sample_period;
4000 
4001 	if (local64_read(&hwc->period_left) > 8*sample_period) {
4002 		if (disable)
4003 			event->pmu->stop(event, PERF_EF_UPDATE);
4004 
4005 		local64_set(&hwc->period_left, 0);
4006 
4007 		if (disable)
4008 			event->pmu->start(event, PERF_EF_RELOAD);
4009 	}
4010 }
4011 
4012 /*
4013  * combine freq adjustment with unthrottling to avoid two passes over the
4014  * events. At the same time, make sure, having freq events does not change
4015  * the rate of unthrottling as that would introduce bias.
4016  */
perf_adjust_freq_unthr_context(struct perf_event_context * ctx,int needs_unthr)4017 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4018 					   int needs_unthr)
4019 {
4020 	struct perf_event *event;
4021 	struct hw_perf_event *hwc;
4022 	u64 now, period = TICK_NSEC;
4023 	s64 delta;
4024 
4025 	/*
4026 	 * only need to iterate over all events iff:
4027 	 * - context have events in frequency mode (needs freq adjust)
4028 	 * - there are events to unthrottle on this cpu
4029 	 */
4030 	if (!(ctx->nr_freq || needs_unthr))
4031 		return;
4032 
4033 	raw_spin_lock(&ctx->lock);
4034 	perf_pmu_disable(ctx->pmu);
4035 
4036 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4037 		if (event->state != PERF_EVENT_STATE_ACTIVE)
4038 			continue;
4039 
4040 		if (!event_filter_match(event))
4041 			continue;
4042 
4043 		perf_pmu_disable(event->pmu);
4044 
4045 		hwc = &event->hw;
4046 
4047 		if (hwc->interrupts == MAX_INTERRUPTS) {
4048 			hwc->interrupts = 0;
4049 			perf_log_throttle(event, 1);
4050 			event->pmu->start(event, 0);
4051 		}
4052 
4053 		if (!event->attr.freq || !event->attr.sample_freq)
4054 			goto next;
4055 
4056 		/*
4057 		 * stop the event and update event->count
4058 		 */
4059 		event->pmu->stop(event, PERF_EF_UPDATE);
4060 
4061 		now = local64_read(&event->count);
4062 		delta = now - hwc->freq_count_stamp;
4063 		hwc->freq_count_stamp = now;
4064 
4065 		/*
4066 		 * restart the event
4067 		 * reload only if value has changed
4068 		 * we have stopped the event so tell that
4069 		 * to perf_adjust_period() to avoid stopping it
4070 		 * twice.
4071 		 */
4072 		if (delta > 0)
4073 			perf_adjust_period(event, period, delta, false);
4074 
4075 		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4076 	next:
4077 		perf_pmu_enable(event->pmu);
4078 	}
4079 
4080 	perf_pmu_enable(ctx->pmu);
4081 	raw_spin_unlock(&ctx->lock);
4082 }
4083 
4084 /*
4085  * Move @event to the tail of the @ctx's elegible events.
4086  */
rotate_ctx(struct perf_event_context * ctx,struct perf_event * event)4087 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4088 {
4089 	/*
4090 	 * Rotate the first entry last of non-pinned groups. Rotation might be
4091 	 * disabled by the inheritance code.
4092 	 */
4093 	if (ctx->rotate_disable)
4094 		return;
4095 
4096 	perf_event_groups_delete(&ctx->flexible_groups, event);
4097 	perf_event_groups_insert(&ctx->flexible_groups, event);
4098 }
4099 
4100 /* pick an event from the flexible_groups to rotate */
4101 static inline struct perf_event *
ctx_event_to_rotate(struct perf_event_context * ctx)4102 ctx_event_to_rotate(struct perf_event_context *ctx)
4103 {
4104 	struct perf_event *event;
4105 
4106 	/* pick the first active flexible event */
4107 	event = list_first_entry_or_null(&ctx->flexible_active,
4108 					 struct perf_event, active_list);
4109 
4110 	/* if no active flexible event, pick the first event */
4111 	if (!event) {
4112 		event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4113 				      typeof(*event), group_node);
4114 	}
4115 
4116 	/*
4117 	 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4118 	 * finds there are unschedulable events, it will set it again.
4119 	 */
4120 	ctx->rotate_necessary = 0;
4121 
4122 	return event;
4123 }
4124 
perf_rotate_context(struct perf_cpu_context * cpuctx)4125 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4126 {
4127 	struct perf_event *cpu_event = NULL, *task_event = NULL;
4128 	struct perf_event_context *task_ctx = NULL;
4129 	int cpu_rotate, task_rotate;
4130 
4131 	/*
4132 	 * Since we run this from IRQ context, nobody can install new
4133 	 * events, thus the event count values are stable.
4134 	 */
4135 
4136 	cpu_rotate = cpuctx->ctx.rotate_necessary;
4137 	task_ctx = cpuctx->task_ctx;
4138 	task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4139 
4140 	if (!(cpu_rotate || task_rotate))
4141 		return false;
4142 
4143 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4144 	perf_pmu_disable(cpuctx->ctx.pmu);
4145 
4146 	if (task_rotate)
4147 		task_event = ctx_event_to_rotate(task_ctx);
4148 	if (cpu_rotate)
4149 		cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4150 
4151 	/*
4152 	 * As per the order given at ctx_resched() first 'pop' task flexible
4153 	 * and then, if needed CPU flexible.
4154 	 */
4155 	if (task_event || (task_ctx && cpu_event))
4156 		ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4157 	if (cpu_event)
4158 		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4159 
4160 	if (task_event)
4161 		rotate_ctx(task_ctx, task_event);
4162 	if (cpu_event)
4163 		rotate_ctx(&cpuctx->ctx, cpu_event);
4164 
4165 	perf_event_sched_in(cpuctx, task_ctx);
4166 
4167 	perf_pmu_enable(cpuctx->ctx.pmu);
4168 	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4169 
4170 	return true;
4171 }
4172 
perf_event_task_tick(void)4173 void perf_event_task_tick(void)
4174 {
4175 	struct list_head *head = this_cpu_ptr(&active_ctx_list);
4176 	struct perf_event_context *ctx, *tmp;
4177 	int throttled;
4178 
4179 	lockdep_assert_irqs_disabled();
4180 
4181 	__this_cpu_inc(perf_throttled_seq);
4182 	throttled = __this_cpu_xchg(perf_throttled_count, 0);
4183 	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4184 
4185 	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4186 		perf_adjust_freq_unthr_context(ctx, throttled);
4187 }
4188 
event_enable_on_exec(struct perf_event * event,struct perf_event_context * ctx)4189 static int event_enable_on_exec(struct perf_event *event,
4190 				struct perf_event_context *ctx)
4191 {
4192 	if (!event->attr.enable_on_exec)
4193 		return 0;
4194 
4195 	event->attr.enable_on_exec = 0;
4196 	if (event->state >= PERF_EVENT_STATE_INACTIVE)
4197 		return 0;
4198 
4199 	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4200 
4201 	return 1;
4202 }
4203 
4204 /*
4205  * Enable all of a task's events that have been marked enable-on-exec.
4206  * This expects task == current.
4207  */
perf_event_enable_on_exec(int ctxn)4208 static void perf_event_enable_on_exec(int ctxn)
4209 {
4210 	struct perf_event_context *ctx, *clone_ctx = NULL;
4211 	enum event_type_t event_type = 0;
4212 	struct perf_cpu_context *cpuctx;
4213 	struct perf_event *event;
4214 	unsigned long flags;
4215 	int enabled = 0;
4216 
4217 	local_irq_save(flags);
4218 	ctx = current->perf_event_ctxp[ctxn];
4219 	if (!ctx || !ctx->nr_events)
4220 		goto out;
4221 
4222 	cpuctx = __get_cpu_context(ctx);
4223 	perf_ctx_lock(cpuctx, ctx);
4224 	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4225 	list_for_each_entry(event, &ctx->event_list, event_entry) {
4226 		enabled |= event_enable_on_exec(event, ctx);
4227 		event_type |= get_event_type(event);
4228 	}
4229 
4230 	/*
4231 	 * Unclone and reschedule this context if we enabled any event.
4232 	 */
4233 	if (enabled) {
4234 		clone_ctx = unclone_ctx(ctx);
4235 		ctx_resched(cpuctx, ctx, event_type);
4236 	} else {
4237 		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
4238 	}
4239 	perf_ctx_unlock(cpuctx, ctx);
4240 
4241 out:
4242 	local_irq_restore(flags);
4243 
4244 	if (clone_ctx)
4245 		put_ctx(clone_ctx);
4246 }
4247 
4248 static void perf_remove_from_owner(struct perf_event *event);
4249 static void perf_event_exit_event(struct perf_event *event,
4250 				  struct perf_event_context *ctx);
4251 
4252 /*
4253  * Removes all events from the current task that have been marked
4254  * remove-on-exec, and feeds their values back to parent events.
4255  */
perf_event_remove_on_exec(int ctxn)4256 static void perf_event_remove_on_exec(int ctxn)
4257 {
4258 	struct perf_event_context *ctx, *clone_ctx = NULL;
4259 	struct perf_event *event, *next;
4260 	unsigned long flags;
4261 	bool modified = false;
4262 
4263 	ctx = perf_pin_task_context(current, ctxn);
4264 	if (!ctx)
4265 		return;
4266 
4267 	mutex_lock(&ctx->mutex);
4268 
4269 	if (WARN_ON_ONCE(ctx->task != current))
4270 		goto unlock;
4271 
4272 	list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4273 		if (!event->attr.remove_on_exec)
4274 			continue;
4275 
4276 		if (!is_kernel_event(event))
4277 			perf_remove_from_owner(event);
4278 
4279 		modified = true;
4280 
4281 		perf_event_exit_event(event, ctx);
4282 	}
4283 
4284 	raw_spin_lock_irqsave(&ctx->lock, flags);
4285 	if (modified)
4286 		clone_ctx = unclone_ctx(ctx);
4287 	--ctx->pin_count;
4288 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
4289 
4290 unlock:
4291 	mutex_unlock(&ctx->mutex);
4292 
4293 	put_ctx(ctx);
4294 	if (clone_ctx)
4295 		put_ctx(clone_ctx);
4296 }
4297 
4298 struct perf_read_data {
4299 	struct perf_event *event;
4300 	bool group;
4301 	int ret;
4302 };
4303 
__perf_event_read_cpu(struct perf_event * event,int event_cpu)4304 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4305 {
4306 	u16 local_pkg, event_pkg;
4307 
4308 	if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4309 		int local_cpu = smp_processor_id();
4310 
4311 		event_pkg = topology_physical_package_id(event_cpu);
4312 		local_pkg = topology_physical_package_id(local_cpu);
4313 
4314 		if (event_pkg == local_pkg)
4315 			return local_cpu;
4316 	}
4317 
4318 	return event_cpu;
4319 }
4320 
4321 /*
4322  * Cross CPU call to read the hardware event
4323  */
__perf_event_read(void * info)4324 static void __perf_event_read(void *info)
4325 {
4326 	struct perf_read_data *data = info;
4327 	struct perf_event *sub, *event = data->event;
4328 	struct perf_event_context *ctx = event->ctx;
4329 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4330 	struct pmu *pmu = event->pmu;
4331 
4332 	/*
4333 	 * If this is a task context, we need to check whether it is
4334 	 * the current task context of this cpu.  If not it has been
4335 	 * scheduled out before the smp call arrived.  In that case
4336 	 * event->count would have been updated to a recent sample
4337 	 * when the event was scheduled out.
4338 	 */
4339 	if (ctx->task && cpuctx->task_ctx != ctx)
4340 		return;
4341 
4342 	raw_spin_lock(&ctx->lock);
4343 	if (ctx->is_active & EVENT_TIME) {
4344 		update_context_time(ctx);
4345 		update_cgrp_time_from_event(event);
4346 	}
4347 
4348 	perf_event_update_time(event);
4349 	if (data->group)
4350 		perf_event_update_sibling_time(event);
4351 
4352 	if (event->state != PERF_EVENT_STATE_ACTIVE)
4353 		goto unlock;
4354 
4355 	if (!data->group) {
4356 		pmu->read(event);
4357 		data->ret = 0;
4358 		goto unlock;
4359 	}
4360 
4361 	pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4362 
4363 	pmu->read(event);
4364 
4365 	for_each_sibling_event(sub, event) {
4366 		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4367 			/*
4368 			 * Use sibling's PMU rather than @event's since
4369 			 * sibling could be on different (eg: software) PMU.
4370 			 */
4371 			sub->pmu->read(sub);
4372 		}
4373 	}
4374 
4375 	data->ret = pmu->commit_txn(pmu);
4376 
4377 unlock:
4378 	raw_spin_unlock(&ctx->lock);
4379 }
4380 
perf_event_count(struct perf_event * event)4381 static inline u64 perf_event_count(struct perf_event *event)
4382 {
4383 	return local64_read(&event->count) + atomic64_read(&event->child_count);
4384 }
4385 
calc_timer_values(struct perf_event * event,u64 * now,u64 * enabled,u64 * running)4386 static void calc_timer_values(struct perf_event *event,
4387 				u64 *now,
4388 				u64 *enabled,
4389 				u64 *running)
4390 {
4391 	u64 ctx_time;
4392 
4393 	*now = perf_clock();
4394 	ctx_time = perf_event_time_now(event, *now);
4395 	__perf_update_times(event, ctx_time, enabled, running);
4396 }
4397 
4398 /*
4399  * NMI-safe method to read a local event, that is an event that
4400  * is:
4401  *   - either for the current task, or for this CPU
4402  *   - does not have inherit set, for inherited task events
4403  *     will not be local and we cannot read them atomically
4404  *   - must not have a pmu::count method
4405  */
perf_event_read_local(struct perf_event * event,u64 * value,u64 * enabled,u64 * running)4406 int perf_event_read_local(struct perf_event *event, u64 *value,
4407 			  u64 *enabled, u64 *running)
4408 {
4409 	unsigned long flags;
4410 	int ret = 0;
4411 
4412 	/*
4413 	 * Disabling interrupts avoids all counter scheduling (context
4414 	 * switches, timer based rotation and IPIs).
4415 	 */
4416 	local_irq_save(flags);
4417 
4418 	/*
4419 	 * It must not be an event with inherit set, we cannot read
4420 	 * all child counters from atomic context.
4421 	 */
4422 	if (event->attr.inherit) {
4423 		ret = -EOPNOTSUPP;
4424 		goto out;
4425 	}
4426 
4427 	/* If this is a per-task event, it must be for current */
4428 	if ((event->attach_state & PERF_ATTACH_TASK) &&
4429 	    event->hw.target != current) {
4430 		ret = -EINVAL;
4431 		goto out;
4432 	}
4433 
4434 	/* If this is a per-CPU event, it must be for this CPU */
4435 	if (!(event->attach_state & PERF_ATTACH_TASK) &&
4436 	    event->cpu != smp_processor_id()) {
4437 		ret = -EINVAL;
4438 		goto out;
4439 	}
4440 
4441 	/* If this is a pinned event it must be running on this CPU */
4442 	if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4443 		ret = -EBUSY;
4444 		goto out;
4445 	}
4446 
4447 	/*
4448 	 * If the event is currently on this CPU, its either a per-task event,
4449 	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4450 	 * oncpu == -1).
4451 	 */
4452 	if (event->oncpu == smp_processor_id())
4453 		event->pmu->read(event);
4454 
4455 	*value = local64_read(&event->count);
4456 	if (enabled || running) {
4457 		u64 __enabled, __running, __now;;
4458 
4459 		calc_timer_values(event, &__now, &__enabled, &__running);
4460 		if (enabled)
4461 			*enabled = __enabled;
4462 		if (running)
4463 			*running = __running;
4464 	}
4465 out:
4466 	local_irq_restore(flags);
4467 
4468 	return ret;
4469 }
4470 
perf_event_read(struct perf_event * event,bool group)4471 static int perf_event_read(struct perf_event *event, bool group)
4472 {
4473 	enum perf_event_state state = READ_ONCE(event->state);
4474 	int event_cpu, ret = 0;
4475 
4476 	/*
4477 	 * If event is enabled and currently active on a CPU, update the
4478 	 * value in the event structure:
4479 	 */
4480 again:
4481 	if (state == PERF_EVENT_STATE_ACTIVE) {
4482 		struct perf_read_data data;
4483 
4484 		/*
4485 		 * Orders the ->state and ->oncpu loads such that if we see
4486 		 * ACTIVE we must also see the right ->oncpu.
4487 		 *
4488 		 * Matches the smp_wmb() from event_sched_in().
4489 		 */
4490 		smp_rmb();
4491 
4492 		event_cpu = READ_ONCE(event->oncpu);
4493 		if ((unsigned)event_cpu >= nr_cpu_ids)
4494 			return 0;
4495 
4496 		data = (struct perf_read_data){
4497 			.event = event,
4498 			.group = group,
4499 			.ret = 0,
4500 		};
4501 
4502 		preempt_disable();
4503 		event_cpu = __perf_event_read_cpu(event, event_cpu);
4504 
4505 		/*
4506 		 * Purposely ignore the smp_call_function_single() return
4507 		 * value.
4508 		 *
4509 		 * If event_cpu isn't a valid CPU it means the event got
4510 		 * scheduled out and that will have updated the event count.
4511 		 *
4512 		 * Therefore, either way, we'll have an up-to-date event count
4513 		 * after this.
4514 		 */
4515 		(void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4516 		preempt_enable();
4517 		ret = data.ret;
4518 
4519 	} else if (state == PERF_EVENT_STATE_INACTIVE) {
4520 		struct perf_event_context *ctx = event->ctx;
4521 		unsigned long flags;
4522 
4523 		raw_spin_lock_irqsave(&ctx->lock, flags);
4524 		state = event->state;
4525 		if (state != PERF_EVENT_STATE_INACTIVE) {
4526 			raw_spin_unlock_irqrestore(&ctx->lock, flags);
4527 			goto again;
4528 		}
4529 
4530 		/*
4531 		 * May read while context is not active (e.g., thread is
4532 		 * blocked), in that case we cannot update context time
4533 		 */
4534 		if (ctx->is_active & EVENT_TIME) {
4535 			update_context_time(ctx);
4536 			update_cgrp_time_from_event(event);
4537 		}
4538 
4539 		perf_event_update_time(event);
4540 		if (group)
4541 			perf_event_update_sibling_time(event);
4542 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4543 	}
4544 
4545 	return ret;
4546 }
4547 
4548 /*
4549  * Initialize the perf_event context in a task_struct:
4550  */
__perf_event_init_context(struct perf_event_context * ctx)4551 static void __perf_event_init_context(struct perf_event_context *ctx)
4552 {
4553 	raw_spin_lock_init(&ctx->lock);
4554 	mutex_init(&ctx->mutex);
4555 	INIT_LIST_HEAD(&ctx->active_ctx_list);
4556 	perf_event_groups_init(&ctx->pinned_groups);
4557 	perf_event_groups_init(&ctx->flexible_groups);
4558 	INIT_LIST_HEAD(&ctx->event_list);
4559 	INIT_LIST_HEAD(&ctx->pinned_active);
4560 	INIT_LIST_HEAD(&ctx->flexible_active);
4561 	refcount_set(&ctx->refcount, 1);
4562 }
4563 
4564 static struct perf_event_context *
alloc_perf_context(struct pmu * pmu,struct task_struct * task)4565 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4566 {
4567 	struct perf_event_context *ctx;
4568 
4569 	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4570 	if (!ctx)
4571 		return NULL;
4572 
4573 	__perf_event_init_context(ctx);
4574 	if (task)
4575 		ctx->task = get_task_struct(task);
4576 	ctx->pmu = pmu;
4577 
4578 	return ctx;
4579 }
4580 
4581 static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)4582 find_lively_task_by_vpid(pid_t vpid)
4583 {
4584 	struct task_struct *task;
4585 
4586 	rcu_read_lock();
4587 	if (!vpid)
4588 		task = current;
4589 	else
4590 		task = find_task_by_vpid(vpid);
4591 	if (task)
4592 		get_task_struct(task);
4593 	rcu_read_unlock();
4594 
4595 	if (!task)
4596 		return ERR_PTR(-ESRCH);
4597 
4598 	return task;
4599 }
4600 
4601 /*
4602  * Returns a matching context with refcount and pincount.
4603  */
4604 static struct perf_event_context *
find_get_context(struct pmu * pmu,struct task_struct * task,struct perf_event * event)4605 find_get_context(struct pmu *pmu, struct task_struct *task,
4606 		struct perf_event *event)
4607 {
4608 	struct perf_event_context *ctx, *clone_ctx = NULL;
4609 	struct perf_cpu_context *cpuctx;
4610 	void *task_ctx_data = NULL;
4611 	unsigned long flags;
4612 	int ctxn, err;
4613 	int cpu = event->cpu;
4614 
4615 	if (!task) {
4616 		/* Must be root to operate on a CPU event: */
4617 		err = perf_allow_cpu(&event->attr);
4618 		if (err)
4619 			return ERR_PTR(err);
4620 
4621 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4622 		ctx = &cpuctx->ctx;
4623 		get_ctx(ctx);
4624 		raw_spin_lock_irqsave(&ctx->lock, flags);
4625 		++ctx->pin_count;
4626 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4627 
4628 		return ctx;
4629 	}
4630 
4631 	err = -EINVAL;
4632 	ctxn = pmu->task_ctx_nr;
4633 	if (ctxn < 0)
4634 		goto errout;
4635 
4636 	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4637 		task_ctx_data = alloc_task_ctx_data(pmu);
4638 		if (!task_ctx_data) {
4639 			err = -ENOMEM;
4640 			goto errout;
4641 		}
4642 	}
4643 
4644 retry:
4645 	ctx = perf_lock_task_context(task, ctxn, &flags);
4646 	if (ctx) {
4647 		clone_ctx = unclone_ctx(ctx);
4648 		++ctx->pin_count;
4649 
4650 		if (task_ctx_data && !ctx->task_ctx_data) {
4651 			ctx->task_ctx_data = task_ctx_data;
4652 			task_ctx_data = NULL;
4653 		}
4654 		raw_spin_unlock_irqrestore(&ctx->lock, flags);
4655 
4656 		if (clone_ctx)
4657 			put_ctx(clone_ctx);
4658 	} else {
4659 		ctx = alloc_perf_context(pmu, task);
4660 		err = -ENOMEM;
4661 		if (!ctx)
4662 			goto errout;
4663 
4664 		if (task_ctx_data) {
4665 			ctx->task_ctx_data = task_ctx_data;
4666 			task_ctx_data = NULL;
4667 		}
4668 
4669 		err = 0;
4670 		mutex_lock(&task->perf_event_mutex);
4671 		/*
4672 		 * If it has already passed perf_event_exit_task().
4673 		 * we must see PF_EXITING, it takes this mutex too.
4674 		 */
4675 		if (task->flags & PF_EXITING)
4676 			err = -ESRCH;
4677 		else if (task->perf_event_ctxp[ctxn])
4678 			err = -EAGAIN;
4679 		else {
4680 			get_ctx(ctx);
4681 			++ctx->pin_count;
4682 			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4683 		}
4684 		mutex_unlock(&task->perf_event_mutex);
4685 
4686 		if (unlikely(err)) {
4687 			put_ctx(ctx);
4688 
4689 			if (err == -EAGAIN)
4690 				goto retry;
4691 			goto errout;
4692 		}
4693 	}
4694 
4695 	free_task_ctx_data(pmu, task_ctx_data);
4696 	return ctx;
4697 
4698 errout:
4699 	free_task_ctx_data(pmu, task_ctx_data);
4700 	return ERR_PTR(err);
4701 }
4702 
4703 static void perf_event_free_filter(struct perf_event *event);
4704 
free_event_rcu(struct rcu_head * head)4705 static void free_event_rcu(struct rcu_head *head)
4706 {
4707 	struct perf_event *event;
4708 
4709 	event = container_of(head, struct perf_event, rcu_head);
4710 	if (event->ns)
4711 		put_pid_ns(event->ns);
4712 	perf_event_free_filter(event);
4713 	kmem_cache_free(perf_event_cache, event);
4714 }
4715 
4716 static void ring_buffer_attach(struct perf_event *event,
4717 			       struct perf_buffer *rb);
4718 
detach_sb_event(struct perf_event * event)4719 static void detach_sb_event(struct perf_event *event)
4720 {
4721 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4722 
4723 	raw_spin_lock(&pel->lock);
4724 	list_del_rcu(&event->sb_list);
4725 	raw_spin_unlock(&pel->lock);
4726 }
4727 
is_sb_event(struct perf_event * event)4728 static bool is_sb_event(struct perf_event *event)
4729 {
4730 	struct perf_event_attr *attr = &event->attr;
4731 
4732 	if (event->parent)
4733 		return false;
4734 
4735 	if (event->attach_state & PERF_ATTACH_TASK)
4736 		return false;
4737 
4738 	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4739 	    attr->comm || attr->comm_exec ||
4740 	    attr->task || attr->ksymbol ||
4741 	    attr->context_switch || attr->text_poke ||
4742 	    attr->bpf_event)
4743 		return true;
4744 	return false;
4745 }
4746 
unaccount_pmu_sb_event(struct perf_event * event)4747 static void unaccount_pmu_sb_event(struct perf_event *event)
4748 {
4749 	if (is_sb_event(event))
4750 		detach_sb_event(event);
4751 }
4752 
unaccount_event_cpu(struct perf_event * event,int cpu)4753 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4754 {
4755 	if (event->parent)
4756 		return;
4757 
4758 	if (is_cgroup_event(event))
4759 		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4760 }
4761 
4762 #ifdef CONFIG_NO_HZ_FULL
4763 static DEFINE_SPINLOCK(nr_freq_lock);
4764 #endif
4765 
unaccount_freq_event_nohz(void)4766 static void unaccount_freq_event_nohz(void)
4767 {
4768 #ifdef CONFIG_NO_HZ_FULL
4769 	spin_lock(&nr_freq_lock);
4770 	if (atomic_dec_and_test(&nr_freq_events))
4771 		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4772 	spin_unlock(&nr_freq_lock);
4773 #endif
4774 }
4775 
unaccount_freq_event(void)4776 static void unaccount_freq_event(void)
4777 {
4778 	if (tick_nohz_full_enabled())
4779 		unaccount_freq_event_nohz();
4780 	else
4781 		atomic_dec(&nr_freq_events);
4782 }
4783 
unaccount_event(struct perf_event * event)4784 static void unaccount_event(struct perf_event *event)
4785 {
4786 	bool dec = false;
4787 
4788 	if (event->parent)
4789 		return;
4790 
4791 	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4792 		dec = true;
4793 	if (event->attr.mmap || event->attr.mmap_data)
4794 		atomic_dec(&nr_mmap_events);
4795 	if (event->attr.build_id)
4796 		atomic_dec(&nr_build_id_events);
4797 	if (event->attr.comm)
4798 		atomic_dec(&nr_comm_events);
4799 	if (event->attr.namespaces)
4800 		atomic_dec(&nr_namespaces_events);
4801 	if (event->attr.cgroup)
4802 		atomic_dec(&nr_cgroup_events);
4803 	if (event->attr.task)
4804 		atomic_dec(&nr_task_events);
4805 	if (event->attr.freq)
4806 		unaccount_freq_event();
4807 	if (event->attr.context_switch) {
4808 		dec = true;
4809 		atomic_dec(&nr_switch_events);
4810 	}
4811 	if (is_cgroup_event(event))
4812 		dec = true;
4813 	if (has_branch_stack(event))
4814 		dec = true;
4815 	if (event->attr.ksymbol)
4816 		atomic_dec(&nr_ksymbol_events);
4817 	if (event->attr.bpf_event)
4818 		atomic_dec(&nr_bpf_events);
4819 	if (event->attr.text_poke)
4820 		atomic_dec(&nr_text_poke_events);
4821 
4822 	if (dec) {
4823 		if (!atomic_add_unless(&perf_sched_count, -1, 1))
4824 			schedule_delayed_work(&perf_sched_work, HZ);
4825 	}
4826 
4827 	unaccount_event_cpu(event, event->cpu);
4828 
4829 	unaccount_pmu_sb_event(event);
4830 }
4831 
perf_sched_delayed(struct work_struct * work)4832 static void perf_sched_delayed(struct work_struct *work)
4833 {
4834 	mutex_lock(&perf_sched_mutex);
4835 	if (atomic_dec_and_test(&perf_sched_count))
4836 		static_branch_disable(&perf_sched_events);
4837 	mutex_unlock(&perf_sched_mutex);
4838 }
4839 
4840 /*
4841  * The following implement mutual exclusion of events on "exclusive" pmus
4842  * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4843  * at a time, so we disallow creating events that might conflict, namely:
4844  *
4845  *  1) cpu-wide events in the presence of per-task events,
4846  *  2) per-task events in the presence of cpu-wide events,
4847  *  3) two matching events on the same context.
4848  *
4849  * The former two cases are handled in the allocation path (perf_event_alloc(),
4850  * _free_event()), the latter -- before the first perf_install_in_context().
4851  */
exclusive_event_init(struct perf_event * event)4852 static int exclusive_event_init(struct perf_event *event)
4853 {
4854 	struct pmu *pmu = event->pmu;
4855 
4856 	if (!is_exclusive_pmu(pmu))
4857 		return 0;
4858 
4859 	/*
4860 	 * Prevent co-existence of per-task and cpu-wide events on the
4861 	 * same exclusive pmu.
4862 	 *
4863 	 * Negative pmu::exclusive_cnt means there are cpu-wide
4864 	 * events on this "exclusive" pmu, positive means there are
4865 	 * per-task events.
4866 	 *
4867 	 * Since this is called in perf_event_alloc() path, event::ctx
4868 	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4869 	 * to mean "per-task event", because unlike other attach states it
4870 	 * never gets cleared.
4871 	 */
4872 	if (event->attach_state & PERF_ATTACH_TASK) {
4873 		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4874 			return -EBUSY;
4875 	} else {
4876 		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4877 			return -EBUSY;
4878 	}
4879 
4880 	return 0;
4881 }
4882 
exclusive_event_destroy(struct perf_event * event)4883 static void exclusive_event_destroy(struct perf_event *event)
4884 {
4885 	struct pmu *pmu = event->pmu;
4886 
4887 	if (!is_exclusive_pmu(pmu))
4888 		return;
4889 
4890 	/* see comment in exclusive_event_init() */
4891 	if (event->attach_state & PERF_ATTACH_TASK)
4892 		atomic_dec(&pmu->exclusive_cnt);
4893 	else
4894 		atomic_inc(&pmu->exclusive_cnt);
4895 }
4896 
exclusive_event_match(struct perf_event * e1,struct perf_event * e2)4897 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4898 {
4899 	if ((e1->pmu == e2->pmu) &&
4900 	    (e1->cpu == e2->cpu ||
4901 	     e1->cpu == -1 ||
4902 	     e2->cpu == -1))
4903 		return true;
4904 	return false;
4905 }
4906 
exclusive_event_installable(struct perf_event * event,struct perf_event_context * ctx)4907 static bool exclusive_event_installable(struct perf_event *event,
4908 					struct perf_event_context *ctx)
4909 {
4910 	struct perf_event *iter_event;
4911 	struct pmu *pmu = event->pmu;
4912 
4913 	lockdep_assert_held(&ctx->mutex);
4914 
4915 	if (!is_exclusive_pmu(pmu))
4916 		return true;
4917 
4918 	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4919 		if (exclusive_event_match(iter_event, event))
4920 			return false;
4921 	}
4922 
4923 	return true;
4924 }
4925 
4926 static void perf_addr_filters_splice(struct perf_event *event,
4927 				       struct list_head *head);
4928 
_free_event(struct perf_event * event)4929 static void _free_event(struct perf_event *event)
4930 {
4931 	irq_work_sync(&event->pending);
4932 
4933 	unaccount_event(event);
4934 
4935 	security_perf_event_free(event);
4936 
4937 	if (event->rb) {
4938 		/*
4939 		 * Can happen when we close an event with re-directed output.
4940 		 *
4941 		 * Since we have a 0 refcount, perf_mmap_close() will skip
4942 		 * over us; possibly making our ring_buffer_put() the last.
4943 		 */
4944 		mutex_lock(&event->mmap_mutex);
4945 		ring_buffer_attach(event, NULL);
4946 		mutex_unlock(&event->mmap_mutex);
4947 	}
4948 
4949 	if (is_cgroup_event(event))
4950 		perf_detach_cgroup(event);
4951 
4952 	if (!event->parent) {
4953 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4954 			put_callchain_buffers();
4955 	}
4956 
4957 	perf_event_free_bpf_prog(event);
4958 	perf_addr_filters_splice(event, NULL);
4959 	kfree(event->addr_filter_ranges);
4960 
4961 	if (event->destroy)
4962 		event->destroy(event);
4963 
4964 	/*
4965 	 * Must be after ->destroy(), due to uprobe_perf_close() using
4966 	 * hw.target.
4967 	 */
4968 	if (event->hw.target)
4969 		put_task_struct(event->hw.target);
4970 
4971 	/*
4972 	 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4973 	 * all task references must be cleaned up.
4974 	 */
4975 	if (event->ctx)
4976 		put_ctx(event->ctx);
4977 
4978 	exclusive_event_destroy(event);
4979 	module_put(event->pmu->module);
4980 
4981 	call_rcu(&event->rcu_head, free_event_rcu);
4982 }
4983 
4984 /*
4985  * Used to free events which have a known refcount of 1, such as in error paths
4986  * where the event isn't exposed yet and inherited events.
4987  */
free_event(struct perf_event * event)4988 static void free_event(struct perf_event *event)
4989 {
4990 	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4991 				"unexpected event refcount: %ld; ptr=%p\n",
4992 				atomic_long_read(&event->refcount), event)) {
4993 		/* leak to avoid use-after-free */
4994 		return;
4995 	}
4996 
4997 	_free_event(event);
4998 }
4999 
5000 /*
5001  * Remove user event from the owner task.
5002  */
perf_remove_from_owner(struct perf_event * event)5003 static void perf_remove_from_owner(struct perf_event *event)
5004 {
5005 	struct task_struct *owner;
5006 
5007 	rcu_read_lock();
5008 	/*
5009 	 * Matches the smp_store_release() in perf_event_exit_task(). If we
5010 	 * observe !owner it means the list deletion is complete and we can
5011 	 * indeed free this event, otherwise we need to serialize on
5012 	 * owner->perf_event_mutex.
5013 	 */
5014 	owner = READ_ONCE(event->owner);
5015 	if (owner) {
5016 		/*
5017 		 * Since delayed_put_task_struct() also drops the last
5018 		 * task reference we can safely take a new reference
5019 		 * while holding the rcu_read_lock().
5020 		 */
5021 		get_task_struct(owner);
5022 	}
5023 	rcu_read_unlock();
5024 
5025 	if (owner) {
5026 		/*
5027 		 * If we're here through perf_event_exit_task() we're already
5028 		 * holding ctx->mutex which would be an inversion wrt. the
5029 		 * normal lock order.
5030 		 *
5031 		 * However we can safely take this lock because its the child
5032 		 * ctx->mutex.
5033 		 */
5034 		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5035 
5036 		/*
5037 		 * We have to re-check the event->owner field, if it is cleared
5038 		 * we raced with perf_event_exit_task(), acquiring the mutex
5039 		 * ensured they're done, and we can proceed with freeing the
5040 		 * event.
5041 		 */
5042 		if (event->owner) {
5043 			list_del_init(&event->owner_entry);
5044 			smp_store_release(&event->owner, NULL);
5045 		}
5046 		mutex_unlock(&owner->perf_event_mutex);
5047 		put_task_struct(owner);
5048 	}
5049 }
5050 
put_event(struct perf_event * event)5051 static void put_event(struct perf_event *event)
5052 {
5053 	if (!atomic_long_dec_and_test(&event->refcount))
5054 		return;
5055 
5056 	_free_event(event);
5057 }
5058 
5059 /*
5060  * Kill an event dead; while event:refcount will preserve the event
5061  * object, it will not preserve its functionality. Once the last 'user'
5062  * gives up the object, we'll destroy the thing.
5063  */
perf_event_release_kernel(struct perf_event * event)5064 int perf_event_release_kernel(struct perf_event *event)
5065 {
5066 	struct perf_event_context *ctx = event->ctx;
5067 	struct perf_event *child, *tmp;
5068 	LIST_HEAD(free_list);
5069 
5070 	/*
5071 	 * If we got here through err_file: fput(event_file); we will not have
5072 	 * attached to a context yet.
5073 	 */
5074 	if (!ctx) {
5075 		WARN_ON_ONCE(event->attach_state &
5076 				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5077 		goto no_ctx;
5078 	}
5079 
5080 	if (!is_kernel_event(event))
5081 		perf_remove_from_owner(event);
5082 
5083 	ctx = perf_event_ctx_lock(event);
5084 	WARN_ON_ONCE(ctx->parent_ctx);
5085 	perf_remove_from_context(event, DETACH_GROUP);
5086 
5087 	raw_spin_lock_irq(&ctx->lock);
5088 	/*
5089 	 * Mark this event as STATE_DEAD, there is no external reference to it
5090 	 * anymore.
5091 	 *
5092 	 * Anybody acquiring event->child_mutex after the below loop _must_
5093 	 * also see this, most importantly inherit_event() which will avoid
5094 	 * placing more children on the list.
5095 	 *
5096 	 * Thus this guarantees that we will in fact observe and kill _ALL_
5097 	 * child events.
5098 	 */
5099 	event->state = PERF_EVENT_STATE_DEAD;
5100 	raw_spin_unlock_irq(&ctx->lock);
5101 
5102 	perf_event_ctx_unlock(event, ctx);
5103 
5104 again:
5105 	mutex_lock(&event->child_mutex);
5106 	list_for_each_entry(child, &event->child_list, child_list) {
5107 
5108 		/*
5109 		 * Cannot change, child events are not migrated, see the
5110 		 * comment with perf_event_ctx_lock_nested().
5111 		 */
5112 		ctx = READ_ONCE(child->ctx);
5113 		/*
5114 		 * Since child_mutex nests inside ctx::mutex, we must jump
5115 		 * through hoops. We start by grabbing a reference on the ctx.
5116 		 *
5117 		 * Since the event cannot get freed while we hold the
5118 		 * child_mutex, the context must also exist and have a !0
5119 		 * reference count.
5120 		 */
5121 		get_ctx(ctx);
5122 
5123 		/*
5124 		 * Now that we have a ctx ref, we can drop child_mutex, and
5125 		 * acquire ctx::mutex without fear of it going away. Then we
5126 		 * can re-acquire child_mutex.
5127 		 */
5128 		mutex_unlock(&event->child_mutex);
5129 		mutex_lock(&ctx->mutex);
5130 		mutex_lock(&event->child_mutex);
5131 
5132 		/*
5133 		 * Now that we hold ctx::mutex and child_mutex, revalidate our
5134 		 * state, if child is still the first entry, it didn't get freed
5135 		 * and we can continue doing so.
5136 		 */
5137 		tmp = list_first_entry_or_null(&event->child_list,
5138 					       struct perf_event, child_list);
5139 		if (tmp == child) {
5140 			perf_remove_from_context(child, DETACH_GROUP);
5141 			list_move(&child->child_list, &free_list);
5142 			/*
5143 			 * This matches the refcount bump in inherit_event();
5144 			 * this can't be the last reference.
5145 			 */
5146 			put_event(event);
5147 		}
5148 
5149 		mutex_unlock(&event->child_mutex);
5150 		mutex_unlock(&ctx->mutex);
5151 		put_ctx(ctx);
5152 		goto again;
5153 	}
5154 	mutex_unlock(&event->child_mutex);
5155 
5156 	list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5157 		void *var = &child->ctx->refcount;
5158 
5159 		list_del(&child->child_list);
5160 		free_event(child);
5161 
5162 		/*
5163 		 * Wake any perf_event_free_task() waiting for this event to be
5164 		 * freed.
5165 		 */
5166 		smp_mb(); /* pairs with wait_var_event() */
5167 		wake_up_var(var);
5168 	}
5169 
5170 no_ctx:
5171 	put_event(event); /* Must be the 'last' reference */
5172 	return 0;
5173 }
5174 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5175 
5176 /*
5177  * Called when the last reference to the file is gone.
5178  */
perf_release(struct inode * inode,struct file * file)5179 static int perf_release(struct inode *inode, struct file *file)
5180 {
5181 	perf_event_release_kernel(file->private_data);
5182 	return 0;
5183 }
5184 
__perf_event_read_value(struct perf_event * event,u64 * enabled,u64 * running)5185 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5186 {
5187 	struct perf_event *child;
5188 	u64 total = 0;
5189 
5190 	*enabled = 0;
5191 	*running = 0;
5192 
5193 	mutex_lock(&event->child_mutex);
5194 
5195 	(void)perf_event_read(event, false);
5196 	total += perf_event_count(event);
5197 
5198 	*enabled += event->total_time_enabled +
5199 			atomic64_read(&event->child_total_time_enabled);
5200 	*running += event->total_time_running +
5201 			atomic64_read(&event->child_total_time_running);
5202 
5203 	list_for_each_entry(child, &event->child_list, child_list) {
5204 		(void)perf_event_read(child, false);
5205 		total += perf_event_count(child);
5206 		*enabled += child->total_time_enabled;
5207 		*running += child->total_time_running;
5208 	}
5209 	mutex_unlock(&event->child_mutex);
5210 
5211 	return total;
5212 }
5213 
perf_event_read_value(struct perf_event * event,u64 * enabled,u64 * running)5214 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5215 {
5216 	struct perf_event_context *ctx;
5217 	u64 count;
5218 
5219 	ctx = perf_event_ctx_lock(event);
5220 	count = __perf_event_read_value(event, enabled, running);
5221 	perf_event_ctx_unlock(event, ctx);
5222 
5223 	return count;
5224 }
5225 EXPORT_SYMBOL_GPL(perf_event_read_value);
5226 
__perf_read_group_add(struct perf_event * leader,u64 read_format,u64 * values)5227 static int __perf_read_group_add(struct perf_event *leader,
5228 					u64 read_format, u64 *values)
5229 {
5230 	struct perf_event_context *ctx = leader->ctx;
5231 	struct perf_event *sub;
5232 	unsigned long flags;
5233 	int n = 1; /* skip @nr */
5234 	int ret;
5235 
5236 	ret = perf_event_read(leader, true);
5237 	if (ret)
5238 		return ret;
5239 
5240 	raw_spin_lock_irqsave(&ctx->lock, flags);
5241 
5242 	/*
5243 	 * Since we co-schedule groups, {enabled,running} times of siblings
5244 	 * will be identical to those of the leader, so we only publish one
5245 	 * set.
5246 	 */
5247 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5248 		values[n++] += leader->total_time_enabled +
5249 			atomic64_read(&leader->child_total_time_enabled);
5250 	}
5251 
5252 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5253 		values[n++] += leader->total_time_running +
5254 			atomic64_read(&leader->child_total_time_running);
5255 	}
5256 
5257 	/*
5258 	 * Write {count,id} tuples for every sibling.
5259 	 */
5260 	values[n++] += perf_event_count(leader);
5261 	if (read_format & PERF_FORMAT_ID)
5262 		values[n++] = primary_event_id(leader);
5263 
5264 	for_each_sibling_event(sub, leader) {
5265 		values[n++] += perf_event_count(sub);
5266 		if (read_format & PERF_FORMAT_ID)
5267 			values[n++] = primary_event_id(sub);
5268 	}
5269 
5270 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
5271 	return 0;
5272 }
5273 
perf_read_group(struct perf_event * event,u64 read_format,char __user * buf)5274 static int perf_read_group(struct perf_event *event,
5275 				   u64 read_format, char __user *buf)
5276 {
5277 	struct perf_event *leader = event->group_leader, *child;
5278 	struct perf_event_context *ctx = leader->ctx;
5279 	int ret;
5280 	u64 *values;
5281 
5282 	lockdep_assert_held(&ctx->mutex);
5283 
5284 	values = kzalloc(event->read_size, GFP_KERNEL);
5285 	if (!values)
5286 		return -ENOMEM;
5287 
5288 	values[0] = 1 + leader->nr_siblings;
5289 
5290 	/*
5291 	 * By locking the child_mutex of the leader we effectively
5292 	 * lock the child list of all siblings.. XXX explain how.
5293 	 */
5294 	mutex_lock(&leader->child_mutex);
5295 
5296 	ret = __perf_read_group_add(leader, read_format, values);
5297 	if (ret)
5298 		goto unlock;
5299 
5300 	list_for_each_entry(child, &leader->child_list, child_list) {
5301 		ret = __perf_read_group_add(child, read_format, values);
5302 		if (ret)
5303 			goto unlock;
5304 	}
5305 
5306 	mutex_unlock(&leader->child_mutex);
5307 
5308 	ret = event->read_size;
5309 	if (copy_to_user(buf, values, event->read_size))
5310 		ret = -EFAULT;
5311 	goto out;
5312 
5313 unlock:
5314 	mutex_unlock(&leader->child_mutex);
5315 out:
5316 	kfree(values);
5317 	return ret;
5318 }
5319 
perf_read_one(struct perf_event * event,u64 read_format,char __user * buf)5320 static int perf_read_one(struct perf_event *event,
5321 				 u64 read_format, char __user *buf)
5322 {
5323 	u64 enabled, running;
5324 	u64 values[4];
5325 	int n = 0;
5326 
5327 	values[n++] = __perf_event_read_value(event, &enabled, &running);
5328 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5329 		values[n++] = enabled;
5330 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5331 		values[n++] = running;
5332 	if (read_format & PERF_FORMAT_ID)
5333 		values[n++] = primary_event_id(event);
5334 
5335 	if (copy_to_user(buf, values, n * sizeof(u64)))
5336 		return -EFAULT;
5337 
5338 	return n * sizeof(u64);
5339 }
5340 
is_event_hup(struct perf_event * event)5341 static bool is_event_hup(struct perf_event *event)
5342 {
5343 	bool no_children;
5344 
5345 	if (event->state > PERF_EVENT_STATE_EXIT)
5346 		return false;
5347 
5348 	mutex_lock(&event->child_mutex);
5349 	no_children = list_empty(&event->child_list);
5350 	mutex_unlock(&event->child_mutex);
5351 	return no_children;
5352 }
5353 
5354 /*
5355  * Read the performance event - simple non blocking version for now
5356  */
5357 static ssize_t
__perf_read(struct perf_event * event,char __user * buf,size_t count)5358 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5359 {
5360 	u64 read_format = event->attr.read_format;
5361 	int ret;
5362 
5363 	/*
5364 	 * Return end-of-file for a read on an event that is in
5365 	 * error state (i.e. because it was pinned but it couldn't be
5366 	 * scheduled on to the CPU at some point).
5367 	 */
5368 	if (event->state == PERF_EVENT_STATE_ERROR)
5369 		return 0;
5370 
5371 	if (count < event->read_size)
5372 		return -ENOSPC;
5373 
5374 	WARN_ON_ONCE(event->ctx->parent_ctx);
5375 	if (read_format & PERF_FORMAT_GROUP)
5376 		ret = perf_read_group(event, read_format, buf);
5377 	else
5378 		ret = perf_read_one(event, read_format, buf);
5379 
5380 	return ret;
5381 }
5382 
5383 static ssize_t
perf_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)5384 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5385 {
5386 	struct perf_event *event = file->private_data;
5387 	struct perf_event_context *ctx;
5388 	int ret;
5389 
5390 	ret = security_perf_event_read(event);
5391 	if (ret)
5392 		return ret;
5393 
5394 	ctx = perf_event_ctx_lock(event);
5395 	ret = __perf_read(event, buf, count);
5396 	perf_event_ctx_unlock(event, ctx);
5397 
5398 	return ret;
5399 }
5400 
perf_poll(struct file * file,poll_table * wait)5401 static __poll_t perf_poll(struct file *file, poll_table *wait)
5402 {
5403 	struct perf_event *event = file->private_data;
5404 	struct perf_buffer *rb;
5405 	__poll_t events = EPOLLHUP;
5406 
5407 	poll_wait(file, &event->waitq, wait);
5408 
5409 	if (is_event_hup(event))
5410 		return events;
5411 
5412 	/*
5413 	 * Pin the event->rb by taking event->mmap_mutex; otherwise
5414 	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5415 	 */
5416 	mutex_lock(&event->mmap_mutex);
5417 	rb = event->rb;
5418 	if (rb)
5419 		events = atomic_xchg(&rb->poll, 0);
5420 	mutex_unlock(&event->mmap_mutex);
5421 	return events;
5422 }
5423 
_perf_event_reset(struct perf_event * event)5424 static void _perf_event_reset(struct perf_event *event)
5425 {
5426 	(void)perf_event_read(event, false);
5427 	local64_set(&event->count, 0);
5428 	perf_event_update_userpage(event);
5429 }
5430 
5431 /* Assume it's not an event with inherit set. */
perf_event_pause(struct perf_event * event,bool reset)5432 u64 perf_event_pause(struct perf_event *event, bool reset)
5433 {
5434 	struct perf_event_context *ctx;
5435 	u64 count;
5436 
5437 	ctx = perf_event_ctx_lock(event);
5438 	WARN_ON_ONCE(event->attr.inherit);
5439 	_perf_event_disable(event);
5440 	count = local64_read(&event->count);
5441 	if (reset)
5442 		local64_set(&event->count, 0);
5443 	perf_event_ctx_unlock(event, ctx);
5444 
5445 	return count;
5446 }
5447 EXPORT_SYMBOL_GPL(perf_event_pause);
5448 
5449 /*
5450  * Holding the top-level event's child_mutex means that any
5451  * descendant process that has inherited this event will block
5452  * in perf_event_exit_event() if it goes to exit, thus satisfying the
5453  * task existence requirements of perf_event_enable/disable.
5454  */
perf_event_for_each_child(struct perf_event * event,void (* func)(struct perf_event *))5455 static void perf_event_for_each_child(struct perf_event *event,
5456 					void (*func)(struct perf_event *))
5457 {
5458 	struct perf_event *child;
5459 
5460 	WARN_ON_ONCE(event->ctx->parent_ctx);
5461 
5462 	mutex_lock(&event->child_mutex);
5463 	func(event);
5464 	list_for_each_entry(child, &event->child_list, child_list)
5465 		func(child);
5466 	mutex_unlock(&event->child_mutex);
5467 }
5468 
perf_event_for_each(struct perf_event * event,void (* func)(struct perf_event *))5469 static void perf_event_for_each(struct perf_event *event,
5470 				  void (*func)(struct perf_event *))
5471 {
5472 	struct perf_event_context *ctx = event->ctx;
5473 	struct perf_event *sibling;
5474 
5475 	lockdep_assert_held(&ctx->mutex);
5476 
5477 	event = event->group_leader;
5478 
5479 	perf_event_for_each_child(event, func);
5480 	for_each_sibling_event(sibling, event)
5481 		perf_event_for_each_child(sibling, func);
5482 }
5483 
__perf_event_period(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)5484 static void __perf_event_period(struct perf_event *event,
5485 				struct perf_cpu_context *cpuctx,
5486 				struct perf_event_context *ctx,
5487 				void *info)
5488 {
5489 	u64 value = *((u64 *)info);
5490 	bool active;
5491 
5492 	if (event->attr.freq) {
5493 		event->attr.sample_freq = value;
5494 	} else {
5495 		event->attr.sample_period = value;
5496 		event->hw.sample_period = value;
5497 	}
5498 
5499 	active = (event->state == PERF_EVENT_STATE_ACTIVE);
5500 	if (active) {
5501 		perf_pmu_disable(ctx->pmu);
5502 		/*
5503 		 * We could be throttled; unthrottle now to avoid the tick
5504 		 * trying to unthrottle while we already re-started the event.
5505 		 */
5506 		if (event->hw.interrupts == MAX_INTERRUPTS) {
5507 			event->hw.interrupts = 0;
5508 			perf_log_throttle(event, 1);
5509 		}
5510 		event->pmu->stop(event, PERF_EF_UPDATE);
5511 	}
5512 
5513 	local64_set(&event->hw.period_left, 0);
5514 
5515 	if (active) {
5516 		event->pmu->start(event, PERF_EF_RELOAD);
5517 		perf_pmu_enable(ctx->pmu);
5518 	}
5519 }
5520 
perf_event_check_period(struct perf_event * event,u64 value)5521 static int perf_event_check_period(struct perf_event *event, u64 value)
5522 {
5523 	return event->pmu->check_period(event, value);
5524 }
5525 
_perf_event_period(struct perf_event * event,u64 value)5526 static int _perf_event_period(struct perf_event *event, u64 value)
5527 {
5528 	if (!is_sampling_event(event))
5529 		return -EINVAL;
5530 
5531 	if (!value)
5532 		return -EINVAL;
5533 
5534 	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5535 		return -EINVAL;
5536 
5537 	if (perf_event_check_period(event, value))
5538 		return -EINVAL;
5539 
5540 	if (!event->attr.freq && (value & (1ULL << 63)))
5541 		return -EINVAL;
5542 
5543 	event_function_call(event, __perf_event_period, &value);
5544 
5545 	return 0;
5546 }
5547 
perf_event_period(struct perf_event * event,u64 value)5548 int perf_event_period(struct perf_event *event, u64 value)
5549 {
5550 	struct perf_event_context *ctx;
5551 	int ret;
5552 
5553 	ctx = perf_event_ctx_lock(event);
5554 	ret = _perf_event_period(event, value);
5555 	perf_event_ctx_unlock(event, ctx);
5556 
5557 	return ret;
5558 }
5559 EXPORT_SYMBOL_GPL(perf_event_period);
5560 
5561 static const struct file_operations perf_fops;
5562 
perf_fget_light(int fd,struct fd * p)5563 static inline int perf_fget_light(int fd, struct fd *p)
5564 {
5565 	struct fd f = fdget(fd);
5566 	if (!f.file)
5567 		return -EBADF;
5568 
5569 	if (f.file->f_op != &perf_fops) {
5570 		fdput(f);
5571 		return -EBADF;
5572 	}
5573 	*p = f;
5574 	return 0;
5575 }
5576 
5577 static int perf_event_set_output(struct perf_event *event,
5578 				 struct perf_event *output_event);
5579 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5580 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5581 			  struct perf_event_attr *attr);
5582 
_perf_ioctl(struct perf_event * event,unsigned int cmd,unsigned long arg)5583 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5584 {
5585 	void (*func)(struct perf_event *);
5586 	u32 flags = arg;
5587 
5588 	switch (cmd) {
5589 	case PERF_EVENT_IOC_ENABLE:
5590 		func = _perf_event_enable;
5591 		break;
5592 	case PERF_EVENT_IOC_DISABLE:
5593 		func = _perf_event_disable;
5594 		break;
5595 	case PERF_EVENT_IOC_RESET:
5596 		func = _perf_event_reset;
5597 		break;
5598 
5599 	case PERF_EVENT_IOC_REFRESH:
5600 		return _perf_event_refresh(event, arg);
5601 
5602 	case PERF_EVENT_IOC_PERIOD:
5603 	{
5604 		u64 value;
5605 
5606 		if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5607 			return -EFAULT;
5608 
5609 		return _perf_event_period(event, value);
5610 	}
5611 	case PERF_EVENT_IOC_ID:
5612 	{
5613 		u64 id = primary_event_id(event);
5614 
5615 		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5616 			return -EFAULT;
5617 		return 0;
5618 	}
5619 
5620 	case PERF_EVENT_IOC_SET_OUTPUT:
5621 	{
5622 		int ret;
5623 		if (arg != -1) {
5624 			struct perf_event *output_event;
5625 			struct fd output;
5626 			ret = perf_fget_light(arg, &output);
5627 			if (ret)
5628 				return ret;
5629 			output_event = output.file->private_data;
5630 			ret = perf_event_set_output(event, output_event);
5631 			fdput(output);
5632 		} else {
5633 			ret = perf_event_set_output(event, NULL);
5634 		}
5635 		return ret;
5636 	}
5637 
5638 	case PERF_EVENT_IOC_SET_FILTER:
5639 		return perf_event_set_filter(event, (void __user *)arg);
5640 
5641 	case PERF_EVENT_IOC_SET_BPF:
5642 	{
5643 		struct bpf_prog *prog;
5644 		int err;
5645 
5646 		prog = bpf_prog_get(arg);
5647 		if (IS_ERR(prog))
5648 			return PTR_ERR(prog);
5649 
5650 		err = perf_event_set_bpf_prog(event, prog, 0);
5651 		if (err) {
5652 			bpf_prog_put(prog);
5653 			return err;
5654 		}
5655 
5656 		return 0;
5657 	}
5658 
5659 	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5660 		struct perf_buffer *rb;
5661 
5662 		rcu_read_lock();
5663 		rb = rcu_dereference(event->rb);
5664 		if (!rb || !rb->nr_pages) {
5665 			rcu_read_unlock();
5666 			return -EINVAL;
5667 		}
5668 		rb_toggle_paused(rb, !!arg);
5669 		rcu_read_unlock();
5670 		return 0;
5671 	}
5672 
5673 	case PERF_EVENT_IOC_QUERY_BPF:
5674 		return perf_event_query_prog_array(event, (void __user *)arg);
5675 
5676 	case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5677 		struct perf_event_attr new_attr;
5678 		int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5679 					 &new_attr);
5680 
5681 		if (err)
5682 			return err;
5683 
5684 		return perf_event_modify_attr(event,  &new_attr);
5685 	}
5686 	default:
5687 		return -ENOTTY;
5688 	}
5689 
5690 	if (flags & PERF_IOC_FLAG_GROUP)
5691 		perf_event_for_each(event, func);
5692 	else
5693 		perf_event_for_each_child(event, func);
5694 
5695 	return 0;
5696 }
5697 
perf_ioctl(struct file * file,unsigned int cmd,unsigned long arg)5698 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5699 {
5700 	struct perf_event *event = file->private_data;
5701 	struct perf_event_context *ctx;
5702 	long ret;
5703 
5704 	/* Treat ioctl like writes as it is likely a mutating operation. */
5705 	ret = security_perf_event_write(event);
5706 	if (ret)
5707 		return ret;
5708 
5709 	ctx = perf_event_ctx_lock(event);
5710 	ret = _perf_ioctl(event, cmd, arg);
5711 	perf_event_ctx_unlock(event, ctx);
5712 
5713 	return ret;
5714 }
5715 
5716 #ifdef CONFIG_COMPAT
perf_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)5717 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5718 				unsigned long arg)
5719 {
5720 	switch (_IOC_NR(cmd)) {
5721 	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5722 	case _IOC_NR(PERF_EVENT_IOC_ID):
5723 	case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5724 	case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5725 		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5726 		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5727 			cmd &= ~IOCSIZE_MASK;
5728 			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5729 		}
5730 		break;
5731 	}
5732 	return perf_ioctl(file, cmd, arg);
5733 }
5734 #else
5735 # define perf_compat_ioctl NULL
5736 #endif
5737 
perf_event_task_enable(void)5738 int perf_event_task_enable(void)
5739 {
5740 	struct perf_event_context *ctx;
5741 	struct perf_event *event;
5742 
5743 	mutex_lock(&current->perf_event_mutex);
5744 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5745 		ctx = perf_event_ctx_lock(event);
5746 		perf_event_for_each_child(event, _perf_event_enable);
5747 		perf_event_ctx_unlock(event, ctx);
5748 	}
5749 	mutex_unlock(&current->perf_event_mutex);
5750 
5751 	return 0;
5752 }
5753 
perf_event_task_disable(void)5754 int perf_event_task_disable(void)
5755 {
5756 	struct perf_event_context *ctx;
5757 	struct perf_event *event;
5758 
5759 	mutex_lock(&current->perf_event_mutex);
5760 	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5761 		ctx = perf_event_ctx_lock(event);
5762 		perf_event_for_each_child(event, _perf_event_disable);
5763 		perf_event_ctx_unlock(event, ctx);
5764 	}
5765 	mutex_unlock(&current->perf_event_mutex);
5766 
5767 	return 0;
5768 }
5769 
perf_event_index(struct perf_event * event)5770 static int perf_event_index(struct perf_event *event)
5771 {
5772 	if (event->hw.state & PERF_HES_STOPPED)
5773 		return 0;
5774 
5775 	if (event->state != PERF_EVENT_STATE_ACTIVE)
5776 		return 0;
5777 
5778 	return event->pmu->event_idx(event);
5779 }
5780 
perf_event_init_userpage(struct perf_event * event)5781 static void perf_event_init_userpage(struct perf_event *event)
5782 {
5783 	struct perf_event_mmap_page *userpg;
5784 	struct perf_buffer *rb;
5785 
5786 	rcu_read_lock();
5787 	rb = rcu_dereference(event->rb);
5788 	if (!rb)
5789 		goto unlock;
5790 
5791 	userpg = rb->user_page;
5792 
5793 	/* Allow new userspace to detect that bit 0 is deprecated */
5794 	userpg->cap_bit0_is_deprecated = 1;
5795 	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5796 	userpg->data_offset = PAGE_SIZE;
5797 	userpg->data_size = perf_data_size(rb);
5798 
5799 unlock:
5800 	rcu_read_unlock();
5801 }
5802 
arch_perf_update_userpage(struct perf_event * event,struct perf_event_mmap_page * userpg,u64 now)5803 void __weak arch_perf_update_userpage(
5804 	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5805 {
5806 }
5807 
5808 /*
5809  * Callers need to ensure there can be no nesting of this function, otherwise
5810  * the seqlock logic goes bad. We can not serialize this because the arch
5811  * code calls this from NMI context.
5812  */
perf_event_update_userpage(struct perf_event * event)5813 void perf_event_update_userpage(struct perf_event *event)
5814 {
5815 	struct perf_event_mmap_page *userpg;
5816 	struct perf_buffer *rb;
5817 	u64 enabled, running, now;
5818 
5819 	rcu_read_lock();
5820 	rb = rcu_dereference(event->rb);
5821 	if (!rb)
5822 		goto unlock;
5823 
5824 	/*
5825 	 * compute total_time_enabled, total_time_running
5826 	 * based on snapshot values taken when the event
5827 	 * was last scheduled in.
5828 	 *
5829 	 * we cannot simply called update_context_time()
5830 	 * because of locking issue as we can be called in
5831 	 * NMI context
5832 	 */
5833 	calc_timer_values(event, &now, &enabled, &running);
5834 
5835 	userpg = rb->user_page;
5836 	/*
5837 	 * Disable preemption to guarantee consistent time stamps are stored to
5838 	 * the user page.
5839 	 */
5840 	preempt_disable();
5841 	++userpg->lock;
5842 	barrier();
5843 	userpg->index = perf_event_index(event);
5844 	userpg->offset = perf_event_count(event);
5845 	if (userpg->index)
5846 		userpg->offset -= local64_read(&event->hw.prev_count);
5847 
5848 	userpg->time_enabled = enabled +
5849 			atomic64_read(&event->child_total_time_enabled);
5850 
5851 	userpg->time_running = running +
5852 			atomic64_read(&event->child_total_time_running);
5853 
5854 	arch_perf_update_userpage(event, userpg, now);
5855 
5856 	barrier();
5857 	++userpg->lock;
5858 	preempt_enable();
5859 unlock:
5860 	rcu_read_unlock();
5861 }
5862 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5863 
perf_mmap_fault(struct vm_fault * vmf)5864 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5865 {
5866 	struct perf_event *event = vmf->vma->vm_file->private_data;
5867 	struct perf_buffer *rb;
5868 	vm_fault_t ret = VM_FAULT_SIGBUS;
5869 
5870 	if (vmf->flags & FAULT_FLAG_MKWRITE) {
5871 		if (vmf->pgoff == 0)
5872 			ret = 0;
5873 		return ret;
5874 	}
5875 
5876 	rcu_read_lock();
5877 	rb = rcu_dereference(event->rb);
5878 	if (!rb)
5879 		goto unlock;
5880 
5881 	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5882 		goto unlock;
5883 
5884 	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5885 	if (!vmf->page)
5886 		goto unlock;
5887 
5888 	get_page(vmf->page);
5889 	vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5890 	vmf->page->index   = vmf->pgoff;
5891 
5892 	ret = 0;
5893 unlock:
5894 	rcu_read_unlock();
5895 
5896 	return ret;
5897 }
5898 
ring_buffer_attach(struct perf_event * event,struct perf_buffer * rb)5899 static void ring_buffer_attach(struct perf_event *event,
5900 			       struct perf_buffer *rb)
5901 {
5902 	struct perf_buffer *old_rb = NULL;
5903 	unsigned long flags;
5904 
5905 	WARN_ON_ONCE(event->parent);
5906 
5907 	if (event->rb) {
5908 		/*
5909 		 * Should be impossible, we set this when removing
5910 		 * event->rb_entry and wait/clear when adding event->rb_entry.
5911 		 */
5912 		WARN_ON_ONCE(event->rcu_pending);
5913 
5914 		old_rb = event->rb;
5915 		spin_lock_irqsave(&old_rb->event_lock, flags);
5916 		list_del_rcu(&event->rb_entry);
5917 		spin_unlock_irqrestore(&old_rb->event_lock, flags);
5918 
5919 		event->rcu_batches = get_state_synchronize_rcu();
5920 		event->rcu_pending = 1;
5921 	}
5922 
5923 	if (rb) {
5924 		if (event->rcu_pending) {
5925 			cond_synchronize_rcu(event->rcu_batches);
5926 			event->rcu_pending = 0;
5927 		}
5928 
5929 		spin_lock_irqsave(&rb->event_lock, flags);
5930 		list_add_rcu(&event->rb_entry, &rb->event_list);
5931 		spin_unlock_irqrestore(&rb->event_lock, flags);
5932 	}
5933 
5934 	/*
5935 	 * Avoid racing with perf_mmap_close(AUX): stop the event
5936 	 * before swizzling the event::rb pointer; if it's getting
5937 	 * unmapped, its aux_mmap_count will be 0 and it won't
5938 	 * restart. See the comment in __perf_pmu_output_stop().
5939 	 *
5940 	 * Data will inevitably be lost when set_output is done in
5941 	 * mid-air, but then again, whoever does it like this is
5942 	 * not in for the data anyway.
5943 	 */
5944 	if (has_aux(event))
5945 		perf_event_stop(event, 0);
5946 
5947 	rcu_assign_pointer(event->rb, rb);
5948 
5949 	if (old_rb) {
5950 		ring_buffer_put(old_rb);
5951 		/*
5952 		 * Since we detached before setting the new rb, so that we
5953 		 * could attach the new rb, we could have missed a wakeup.
5954 		 * Provide it now.
5955 		 */
5956 		wake_up_all(&event->waitq);
5957 	}
5958 }
5959 
ring_buffer_wakeup(struct perf_event * event)5960 static void ring_buffer_wakeup(struct perf_event *event)
5961 {
5962 	struct perf_buffer *rb;
5963 
5964 	if (event->parent)
5965 		event = event->parent;
5966 
5967 	rcu_read_lock();
5968 	rb = rcu_dereference(event->rb);
5969 	if (rb) {
5970 		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5971 			wake_up_all(&event->waitq);
5972 	}
5973 	rcu_read_unlock();
5974 }
5975 
ring_buffer_get(struct perf_event * event)5976 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5977 {
5978 	struct perf_buffer *rb;
5979 
5980 	if (event->parent)
5981 		event = event->parent;
5982 
5983 	rcu_read_lock();
5984 	rb = rcu_dereference(event->rb);
5985 	if (rb) {
5986 		if (!refcount_inc_not_zero(&rb->refcount))
5987 			rb = NULL;
5988 	}
5989 	rcu_read_unlock();
5990 
5991 	return rb;
5992 }
5993 
ring_buffer_put(struct perf_buffer * rb)5994 void ring_buffer_put(struct perf_buffer *rb)
5995 {
5996 	if (!refcount_dec_and_test(&rb->refcount))
5997 		return;
5998 
5999 	WARN_ON_ONCE(!list_empty(&rb->event_list));
6000 
6001 	call_rcu(&rb->rcu_head, rb_free_rcu);
6002 }
6003 
perf_mmap_open(struct vm_area_struct * vma)6004 static void perf_mmap_open(struct vm_area_struct *vma)
6005 {
6006 	struct perf_event *event = vma->vm_file->private_data;
6007 
6008 	atomic_inc(&event->mmap_count);
6009 	atomic_inc(&event->rb->mmap_count);
6010 
6011 	if (vma->vm_pgoff)
6012 		atomic_inc(&event->rb->aux_mmap_count);
6013 
6014 	if (event->pmu->event_mapped)
6015 		event->pmu->event_mapped(event, vma->vm_mm);
6016 }
6017 
6018 static void perf_pmu_output_stop(struct perf_event *event);
6019 
6020 /*
6021  * A buffer can be mmap()ed multiple times; either directly through the same
6022  * event, or through other events by use of perf_event_set_output().
6023  *
6024  * In order to undo the VM accounting done by perf_mmap() we need to destroy
6025  * the buffer here, where we still have a VM context. This means we need
6026  * to detach all events redirecting to us.
6027  */
perf_mmap_close(struct vm_area_struct * vma)6028 static void perf_mmap_close(struct vm_area_struct *vma)
6029 {
6030 	struct perf_event *event = vma->vm_file->private_data;
6031 	struct perf_buffer *rb = ring_buffer_get(event);
6032 	struct user_struct *mmap_user = rb->mmap_user;
6033 	int mmap_locked = rb->mmap_locked;
6034 	unsigned long size = perf_data_size(rb);
6035 	bool detach_rest = false;
6036 
6037 	if (event->pmu->event_unmapped)
6038 		event->pmu->event_unmapped(event, vma->vm_mm);
6039 
6040 	/*
6041 	 * rb->aux_mmap_count will always drop before rb->mmap_count and
6042 	 * event->mmap_count, so it is ok to use event->mmap_mutex to
6043 	 * serialize with perf_mmap here.
6044 	 */
6045 	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6046 	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6047 		/*
6048 		 * Stop all AUX events that are writing to this buffer,
6049 		 * so that we can free its AUX pages and corresponding PMU
6050 		 * data. Note that after rb::aux_mmap_count dropped to zero,
6051 		 * they won't start any more (see perf_aux_output_begin()).
6052 		 */
6053 		perf_pmu_output_stop(event);
6054 
6055 		/* now it's safe to free the pages */
6056 		atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6057 		atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6058 
6059 		/* this has to be the last one */
6060 		rb_free_aux(rb);
6061 		WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6062 
6063 		mutex_unlock(&event->mmap_mutex);
6064 	}
6065 
6066 	if (atomic_dec_and_test(&rb->mmap_count))
6067 		detach_rest = true;
6068 
6069 	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6070 		goto out_put;
6071 
6072 	ring_buffer_attach(event, NULL);
6073 	mutex_unlock(&event->mmap_mutex);
6074 
6075 	/* If there's still other mmap()s of this buffer, we're done. */
6076 	if (!detach_rest)
6077 		goto out_put;
6078 
6079 	/*
6080 	 * No other mmap()s, detach from all other events that might redirect
6081 	 * into the now unreachable buffer. Somewhat complicated by the
6082 	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6083 	 */
6084 again:
6085 	rcu_read_lock();
6086 	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6087 		if (!atomic_long_inc_not_zero(&event->refcount)) {
6088 			/*
6089 			 * This event is en-route to free_event() which will
6090 			 * detach it and remove it from the list.
6091 			 */
6092 			continue;
6093 		}
6094 		rcu_read_unlock();
6095 
6096 		mutex_lock(&event->mmap_mutex);
6097 		/*
6098 		 * Check we didn't race with perf_event_set_output() which can
6099 		 * swizzle the rb from under us while we were waiting to
6100 		 * acquire mmap_mutex.
6101 		 *
6102 		 * If we find a different rb; ignore this event, a next
6103 		 * iteration will no longer find it on the list. We have to
6104 		 * still restart the iteration to make sure we're not now
6105 		 * iterating the wrong list.
6106 		 */
6107 		if (event->rb == rb)
6108 			ring_buffer_attach(event, NULL);
6109 
6110 		mutex_unlock(&event->mmap_mutex);
6111 		put_event(event);
6112 
6113 		/*
6114 		 * Restart the iteration; either we're on the wrong list or
6115 		 * destroyed its integrity by doing a deletion.
6116 		 */
6117 		goto again;
6118 	}
6119 	rcu_read_unlock();
6120 
6121 	/*
6122 	 * It could be there's still a few 0-ref events on the list; they'll
6123 	 * get cleaned up by free_event() -- they'll also still have their
6124 	 * ref on the rb and will free it whenever they are done with it.
6125 	 *
6126 	 * Aside from that, this buffer is 'fully' detached and unmapped,
6127 	 * undo the VM accounting.
6128 	 */
6129 
6130 	atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6131 			&mmap_user->locked_vm);
6132 	atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6133 	free_uid(mmap_user);
6134 
6135 out_put:
6136 	ring_buffer_put(rb); /* could be last */
6137 }
6138 
6139 static const struct vm_operations_struct perf_mmap_vmops = {
6140 	.open		= perf_mmap_open,
6141 	.close		= perf_mmap_close, /* non mergeable */
6142 	.fault		= perf_mmap_fault,
6143 	.page_mkwrite	= perf_mmap_fault,
6144 };
6145 
perf_mmap(struct file * file,struct vm_area_struct * vma)6146 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6147 {
6148 	struct perf_event *event = file->private_data;
6149 	unsigned long user_locked, user_lock_limit;
6150 	struct user_struct *user = current_user();
6151 	struct perf_buffer *rb = NULL;
6152 	unsigned long locked, lock_limit;
6153 	unsigned long vma_size;
6154 	unsigned long nr_pages;
6155 	long user_extra = 0, extra = 0;
6156 	int ret = 0, flags = 0;
6157 
6158 	/*
6159 	 * Don't allow mmap() of inherited per-task counters. This would
6160 	 * create a performance issue due to all children writing to the
6161 	 * same rb.
6162 	 */
6163 	if (event->cpu == -1 && event->attr.inherit)
6164 		return -EINVAL;
6165 
6166 	if (!(vma->vm_flags & VM_SHARED))
6167 		return -EINVAL;
6168 
6169 	ret = security_perf_event_read(event);
6170 	if (ret)
6171 		return ret;
6172 
6173 	vma_size = vma->vm_end - vma->vm_start;
6174 
6175 	if (vma->vm_pgoff == 0) {
6176 		nr_pages = (vma_size / PAGE_SIZE) - 1;
6177 	} else {
6178 		/*
6179 		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6180 		 * mapped, all subsequent mappings should have the same size
6181 		 * and offset. Must be above the normal perf buffer.
6182 		 */
6183 		u64 aux_offset, aux_size;
6184 
6185 		if (!event->rb)
6186 			return -EINVAL;
6187 
6188 		nr_pages = vma_size / PAGE_SIZE;
6189 
6190 		mutex_lock(&event->mmap_mutex);
6191 		ret = -EINVAL;
6192 
6193 		rb = event->rb;
6194 		if (!rb)
6195 			goto aux_unlock;
6196 
6197 		aux_offset = READ_ONCE(rb->user_page->aux_offset);
6198 		aux_size = READ_ONCE(rb->user_page->aux_size);
6199 
6200 		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6201 			goto aux_unlock;
6202 
6203 		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6204 			goto aux_unlock;
6205 
6206 		/* already mapped with a different offset */
6207 		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6208 			goto aux_unlock;
6209 
6210 		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6211 			goto aux_unlock;
6212 
6213 		/* already mapped with a different size */
6214 		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6215 			goto aux_unlock;
6216 
6217 		if (!is_power_of_2(nr_pages))
6218 			goto aux_unlock;
6219 
6220 		if (!atomic_inc_not_zero(&rb->mmap_count))
6221 			goto aux_unlock;
6222 
6223 		if (rb_has_aux(rb)) {
6224 			atomic_inc(&rb->aux_mmap_count);
6225 			ret = 0;
6226 			goto unlock;
6227 		}
6228 
6229 		atomic_set(&rb->aux_mmap_count, 1);
6230 		user_extra = nr_pages;
6231 
6232 		goto accounting;
6233 	}
6234 
6235 	/*
6236 	 * If we have rb pages ensure they're a power-of-two number, so we
6237 	 * can do bitmasks instead of modulo.
6238 	 */
6239 	if (nr_pages != 0 && !is_power_of_2(nr_pages))
6240 		return -EINVAL;
6241 
6242 	if (vma_size != PAGE_SIZE * (1 + nr_pages))
6243 		return -EINVAL;
6244 
6245 	WARN_ON_ONCE(event->ctx->parent_ctx);
6246 again:
6247 	mutex_lock(&event->mmap_mutex);
6248 	if (event->rb) {
6249 		if (data_page_nr(event->rb) != nr_pages) {
6250 			ret = -EINVAL;
6251 			goto unlock;
6252 		}
6253 
6254 		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6255 			/*
6256 			 * Raced against perf_mmap_close(); remove the
6257 			 * event and try again.
6258 			 */
6259 			ring_buffer_attach(event, NULL);
6260 			mutex_unlock(&event->mmap_mutex);
6261 			goto again;
6262 		}
6263 
6264 		goto unlock;
6265 	}
6266 
6267 	user_extra = nr_pages + 1;
6268 
6269 accounting:
6270 	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6271 
6272 	/*
6273 	 * Increase the limit linearly with more CPUs:
6274 	 */
6275 	user_lock_limit *= num_online_cpus();
6276 
6277 	user_locked = atomic_long_read(&user->locked_vm);
6278 
6279 	/*
6280 	 * sysctl_perf_event_mlock may have changed, so that
6281 	 *     user->locked_vm > user_lock_limit
6282 	 */
6283 	if (user_locked > user_lock_limit)
6284 		user_locked = user_lock_limit;
6285 	user_locked += user_extra;
6286 
6287 	if (user_locked > user_lock_limit) {
6288 		/*
6289 		 * charge locked_vm until it hits user_lock_limit;
6290 		 * charge the rest from pinned_vm
6291 		 */
6292 		extra = user_locked - user_lock_limit;
6293 		user_extra -= extra;
6294 	}
6295 
6296 	lock_limit = rlimit(RLIMIT_MEMLOCK);
6297 	lock_limit >>= PAGE_SHIFT;
6298 	locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6299 
6300 	if ((locked > lock_limit) && perf_is_paranoid() &&
6301 		!capable(CAP_IPC_LOCK)) {
6302 		ret = -EPERM;
6303 		goto unlock;
6304 	}
6305 
6306 	WARN_ON(!rb && event->rb);
6307 
6308 	if (vma->vm_flags & VM_WRITE)
6309 		flags |= RING_BUFFER_WRITABLE;
6310 
6311 	if (!rb) {
6312 		rb = rb_alloc(nr_pages,
6313 			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
6314 			      event->cpu, flags);
6315 
6316 		if (!rb) {
6317 			ret = -ENOMEM;
6318 			goto unlock;
6319 		}
6320 
6321 		atomic_set(&rb->mmap_count, 1);
6322 		rb->mmap_user = get_current_user();
6323 		rb->mmap_locked = extra;
6324 
6325 		ring_buffer_attach(event, rb);
6326 
6327 		perf_event_update_time(event);
6328 		perf_event_init_userpage(event);
6329 		perf_event_update_userpage(event);
6330 	} else {
6331 		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6332 				   event->attr.aux_watermark, flags);
6333 		if (!ret)
6334 			rb->aux_mmap_locked = extra;
6335 	}
6336 
6337 unlock:
6338 	if (!ret) {
6339 		atomic_long_add(user_extra, &user->locked_vm);
6340 		atomic64_add(extra, &vma->vm_mm->pinned_vm);
6341 
6342 		atomic_inc(&event->mmap_count);
6343 	} else if (rb) {
6344 		atomic_dec(&rb->mmap_count);
6345 	}
6346 aux_unlock:
6347 	mutex_unlock(&event->mmap_mutex);
6348 
6349 	/*
6350 	 * Since pinned accounting is per vm we cannot allow fork() to copy our
6351 	 * vma.
6352 	 */
6353 	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6354 	vma->vm_ops = &perf_mmap_vmops;
6355 
6356 	if (event->pmu->event_mapped)
6357 		event->pmu->event_mapped(event, vma->vm_mm);
6358 
6359 	return ret;
6360 }
6361 
perf_fasync(int fd,struct file * filp,int on)6362 static int perf_fasync(int fd, struct file *filp, int on)
6363 {
6364 	struct inode *inode = file_inode(filp);
6365 	struct perf_event *event = filp->private_data;
6366 	int retval;
6367 
6368 	inode_lock(inode);
6369 	retval = fasync_helper(fd, filp, on, &event->fasync);
6370 	inode_unlock(inode);
6371 
6372 	if (retval < 0)
6373 		return retval;
6374 
6375 	return 0;
6376 }
6377 
6378 static const struct file_operations perf_fops = {
6379 	.llseek			= no_llseek,
6380 	.release		= perf_release,
6381 	.read			= perf_read,
6382 	.poll			= perf_poll,
6383 	.unlocked_ioctl		= perf_ioctl,
6384 	.compat_ioctl		= perf_compat_ioctl,
6385 	.mmap			= perf_mmap,
6386 	.fasync			= perf_fasync,
6387 };
6388 
6389 /*
6390  * Perf event wakeup
6391  *
6392  * If there's data, ensure we set the poll() state and publish everything
6393  * to user-space before waking everybody up.
6394  */
6395 
perf_event_fasync(struct perf_event * event)6396 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6397 {
6398 	/* only the parent has fasync state */
6399 	if (event->parent)
6400 		event = event->parent;
6401 	return &event->fasync;
6402 }
6403 
perf_event_wakeup(struct perf_event * event)6404 void perf_event_wakeup(struct perf_event *event)
6405 {
6406 	ring_buffer_wakeup(event);
6407 
6408 	if (event->pending_kill) {
6409 		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6410 		event->pending_kill = 0;
6411 	}
6412 }
6413 
perf_sigtrap(struct perf_event * event)6414 static void perf_sigtrap(struct perf_event *event)
6415 {
6416 	/*
6417 	 * We'd expect this to only occur if the irq_work is delayed and either
6418 	 * ctx->task or current has changed in the meantime. This can be the
6419 	 * case on architectures that do not implement arch_irq_work_raise().
6420 	 */
6421 	if (WARN_ON_ONCE(event->ctx->task != current))
6422 		return;
6423 
6424 	/*
6425 	 * perf_pending_event() can race with the task exiting.
6426 	 */
6427 	if (current->flags & PF_EXITING)
6428 		return;
6429 
6430 	send_sig_perf((void __user *)event->pending_addr,
6431 		      event->attr.type, event->attr.sig_data);
6432 }
6433 
perf_pending_event_disable(struct perf_event * event)6434 static void perf_pending_event_disable(struct perf_event *event)
6435 {
6436 	int cpu = READ_ONCE(event->pending_disable);
6437 
6438 	if (cpu < 0)
6439 		return;
6440 
6441 	if (cpu == smp_processor_id()) {
6442 		WRITE_ONCE(event->pending_disable, -1);
6443 
6444 		if (event->attr.sigtrap) {
6445 			perf_sigtrap(event);
6446 			atomic_set_release(&event->event_limit, 1); /* rearm event */
6447 			return;
6448 		}
6449 
6450 		perf_event_disable_local(event);
6451 		return;
6452 	}
6453 
6454 	/*
6455 	 *  CPU-A			CPU-B
6456 	 *
6457 	 *  perf_event_disable_inatomic()
6458 	 *    @pending_disable = CPU-A;
6459 	 *    irq_work_queue();
6460 	 *
6461 	 *  sched-out
6462 	 *    @pending_disable = -1;
6463 	 *
6464 	 *				sched-in
6465 	 *				perf_event_disable_inatomic()
6466 	 *				  @pending_disable = CPU-B;
6467 	 *				  irq_work_queue(); // FAILS
6468 	 *
6469 	 *  irq_work_run()
6470 	 *    perf_pending_event()
6471 	 *
6472 	 * But the event runs on CPU-B and wants disabling there.
6473 	 */
6474 	irq_work_queue_on(&event->pending, cpu);
6475 }
6476 
perf_pending_event(struct irq_work * entry)6477 static void perf_pending_event(struct irq_work *entry)
6478 {
6479 	struct perf_event *event = container_of(entry, struct perf_event, pending);
6480 	int rctx;
6481 
6482 	rctx = perf_swevent_get_recursion_context();
6483 	/*
6484 	 * If we 'fail' here, that's OK, it means recursion is already disabled
6485 	 * and we won't recurse 'further'.
6486 	 */
6487 
6488 	perf_pending_event_disable(event);
6489 
6490 	if (event->pending_wakeup) {
6491 		event->pending_wakeup = 0;
6492 		perf_event_wakeup(event);
6493 	}
6494 
6495 	if (rctx >= 0)
6496 		perf_swevent_put_recursion_context(rctx);
6497 }
6498 
6499 #ifdef CONFIG_GUEST_PERF_EVENTS
6500 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6501 
6502 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6503 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6504 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6505 
perf_register_guest_info_callbacks(struct perf_guest_info_callbacks * cbs)6506 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6507 {
6508 	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6509 		return;
6510 
6511 	rcu_assign_pointer(perf_guest_cbs, cbs);
6512 	static_call_update(__perf_guest_state, cbs->state);
6513 	static_call_update(__perf_guest_get_ip, cbs->get_ip);
6514 
6515 	/* Implementing ->handle_intel_pt_intr is optional. */
6516 	if (cbs->handle_intel_pt_intr)
6517 		static_call_update(__perf_guest_handle_intel_pt_intr,
6518 				   cbs->handle_intel_pt_intr);
6519 }
6520 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6521 
perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks * cbs)6522 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6523 {
6524 	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6525 		return;
6526 
6527 	rcu_assign_pointer(perf_guest_cbs, NULL);
6528 	static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6529 	static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6530 	static_call_update(__perf_guest_handle_intel_pt_intr,
6531 			   (void *)&__static_call_return0);
6532 	synchronize_rcu();
6533 }
6534 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6535 #endif
6536 
6537 static void
perf_output_sample_regs(struct perf_output_handle * handle,struct pt_regs * regs,u64 mask)6538 perf_output_sample_regs(struct perf_output_handle *handle,
6539 			struct pt_regs *regs, u64 mask)
6540 {
6541 	int bit;
6542 	DECLARE_BITMAP(_mask, 64);
6543 
6544 	bitmap_from_u64(_mask, mask);
6545 	for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6546 		u64 val;
6547 
6548 		val = perf_reg_value(regs, bit);
6549 		perf_output_put(handle, val);
6550 	}
6551 }
6552 
perf_sample_regs_user(struct perf_regs * regs_user,struct pt_regs * regs)6553 static void perf_sample_regs_user(struct perf_regs *regs_user,
6554 				  struct pt_regs *regs)
6555 {
6556 	if (user_mode(regs)) {
6557 		regs_user->abi = perf_reg_abi(current);
6558 		regs_user->regs = regs;
6559 	} else if (!(current->flags & PF_KTHREAD)) {
6560 		perf_get_regs_user(regs_user, regs);
6561 	} else {
6562 		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6563 		regs_user->regs = NULL;
6564 	}
6565 }
6566 
perf_sample_regs_intr(struct perf_regs * regs_intr,struct pt_regs * regs)6567 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6568 				  struct pt_regs *regs)
6569 {
6570 	regs_intr->regs = regs;
6571 	regs_intr->abi  = perf_reg_abi(current);
6572 }
6573 
6574 
6575 /*
6576  * Get remaining task size from user stack pointer.
6577  *
6578  * It'd be better to take stack vma map and limit this more
6579  * precisely, but there's no way to get it safely under interrupt,
6580  * so using TASK_SIZE as limit.
6581  */
perf_ustack_task_size(struct pt_regs * regs)6582 static u64 perf_ustack_task_size(struct pt_regs *regs)
6583 {
6584 	unsigned long addr = perf_user_stack_pointer(regs);
6585 
6586 	if (!addr || addr >= TASK_SIZE)
6587 		return 0;
6588 
6589 	return TASK_SIZE - addr;
6590 }
6591 
6592 static u16
perf_sample_ustack_size(u16 stack_size,u16 header_size,struct pt_regs * regs)6593 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6594 			struct pt_regs *regs)
6595 {
6596 	u64 task_size;
6597 
6598 	/* No regs, no stack pointer, no dump. */
6599 	if (!regs)
6600 		return 0;
6601 
6602 	/*
6603 	 * Check if we fit in with the requested stack size into the:
6604 	 * - TASK_SIZE
6605 	 *   If we don't, we limit the size to the TASK_SIZE.
6606 	 *
6607 	 * - remaining sample size
6608 	 *   If we don't, we customize the stack size to
6609 	 *   fit in to the remaining sample size.
6610 	 */
6611 
6612 	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6613 	stack_size = min(stack_size, (u16) task_size);
6614 
6615 	/* Current header size plus static size and dynamic size. */
6616 	header_size += 2 * sizeof(u64);
6617 
6618 	/* Do we fit in with the current stack dump size? */
6619 	if ((u16) (header_size + stack_size) < header_size) {
6620 		/*
6621 		 * If we overflow the maximum size for the sample,
6622 		 * we customize the stack dump size to fit in.
6623 		 */
6624 		stack_size = USHRT_MAX - header_size - sizeof(u64);
6625 		stack_size = round_up(stack_size, sizeof(u64));
6626 	}
6627 
6628 	return stack_size;
6629 }
6630 
6631 static void
perf_output_sample_ustack(struct perf_output_handle * handle,u64 dump_size,struct pt_regs * regs)6632 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6633 			  struct pt_regs *regs)
6634 {
6635 	/* Case of a kernel thread, nothing to dump */
6636 	if (!regs) {
6637 		u64 size = 0;
6638 		perf_output_put(handle, size);
6639 	} else {
6640 		unsigned long sp;
6641 		unsigned int rem;
6642 		u64 dyn_size;
6643 
6644 		/*
6645 		 * We dump:
6646 		 * static size
6647 		 *   - the size requested by user or the best one we can fit
6648 		 *     in to the sample max size
6649 		 * data
6650 		 *   - user stack dump data
6651 		 * dynamic size
6652 		 *   - the actual dumped size
6653 		 */
6654 
6655 		/* Static size. */
6656 		perf_output_put(handle, dump_size);
6657 
6658 		/* Data. */
6659 		sp = perf_user_stack_pointer(regs);
6660 		rem = __output_copy_user(handle, (void *) sp, dump_size);
6661 		dyn_size = dump_size - rem;
6662 
6663 		perf_output_skip(handle, rem);
6664 
6665 		/* Dynamic size. */
6666 		perf_output_put(handle, dyn_size);
6667 	}
6668 }
6669 
perf_prepare_sample_aux(struct perf_event * event,struct perf_sample_data * data,size_t size)6670 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6671 					  struct perf_sample_data *data,
6672 					  size_t size)
6673 {
6674 	struct perf_event *sampler = event->aux_event;
6675 	struct perf_buffer *rb;
6676 
6677 	data->aux_size = 0;
6678 
6679 	if (!sampler)
6680 		goto out;
6681 
6682 	if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6683 		goto out;
6684 
6685 	if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6686 		goto out;
6687 
6688 	rb = ring_buffer_get(sampler);
6689 	if (!rb)
6690 		goto out;
6691 
6692 	/*
6693 	 * If this is an NMI hit inside sampling code, don't take
6694 	 * the sample. See also perf_aux_sample_output().
6695 	 */
6696 	if (READ_ONCE(rb->aux_in_sampling)) {
6697 		data->aux_size = 0;
6698 	} else {
6699 		size = min_t(size_t, size, perf_aux_size(rb));
6700 		data->aux_size = ALIGN(size, sizeof(u64));
6701 	}
6702 	ring_buffer_put(rb);
6703 
6704 out:
6705 	return data->aux_size;
6706 }
6707 
perf_pmu_snapshot_aux(struct perf_buffer * rb,struct perf_event * event,struct perf_output_handle * handle,unsigned long size)6708 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6709                                  struct perf_event *event,
6710                                  struct perf_output_handle *handle,
6711                                  unsigned long size)
6712 {
6713 	unsigned long flags;
6714 	long ret;
6715 
6716 	/*
6717 	 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6718 	 * paths. If we start calling them in NMI context, they may race with
6719 	 * the IRQ ones, that is, for example, re-starting an event that's just
6720 	 * been stopped, which is why we're using a separate callback that
6721 	 * doesn't change the event state.
6722 	 *
6723 	 * IRQs need to be disabled to prevent IPIs from racing with us.
6724 	 */
6725 	local_irq_save(flags);
6726 	/*
6727 	 * Guard against NMI hits inside the critical section;
6728 	 * see also perf_prepare_sample_aux().
6729 	 */
6730 	WRITE_ONCE(rb->aux_in_sampling, 1);
6731 	barrier();
6732 
6733 	ret = event->pmu->snapshot_aux(event, handle, size);
6734 
6735 	barrier();
6736 	WRITE_ONCE(rb->aux_in_sampling, 0);
6737 	local_irq_restore(flags);
6738 
6739 	return ret;
6740 }
6741 
perf_aux_sample_output(struct perf_event * event,struct perf_output_handle * handle,struct perf_sample_data * data)6742 static void perf_aux_sample_output(struct perf_event *event,
6743 				   struct perf_output_handle *handle,
6744 				   struct perf_sample_data *data)
6745 {
6746 	struct perf_event *sampler = event->aux_event;
6747 	struct perf_buffer *rb;
6748 	unsigned long pad;
6749 	long size;
6750 
6751 	if (WARN_ON_ONCE(!sampler || !data->aux_size))
6752 		return;
6753 
6754 	rb = ring_buffer_get(sampler);
6755 	if (!rb)
6756 		return;
6757 
6758 	size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6759 
6760 	/*
6761 	 * An error here means that perf_output_copy() failed (returned a
6762 	 * non-zero surplus that it didn't copy), which in its current
6763 	 * enlightened implementation is not possible. If that changes, we'd
6764 	 * like to know.
6765 	 */
6766 	if (WARN_ON_ONCE(size < 0))
6767 		goto out_put;
6768 
6769 	/*
6770 	 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6771 	 * perf_prepare_sample_aux(), so should not be more than that.
6772 	 */
6773 	pad = data->aux_size - size;
6774 	if (WARN_ON_ONCE(pad >= sizeof(u64)))
6775 		pad = 8;
6776 
6777 	if (pad) {
6778 		u64 zero = 0;
6779 		perf_output_copy(handle, &zero, pad);
6780 	}
6781 
6782 out_put:
6783 	ring_buffer_put(rb);
6784 }
6785 
__perf_event_header__init_id(struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event)6786 static void __perf_event_header__init_id(struct perf_event_header *header,
6787 					 struct perf_sample_data *data,
6788 					 struct perf_event *event)
6789 {
6790 	u64 sample_type = event->attr.sample_type;
6791 
6792 	data->type = sample_type;
6793 	header->size += event->id_header_size;
6794 
6795 	if (sample_type & PERF_SAMPLE_TID) {
6796 		/* namespace issues */
6797 		data->tid_entry.pid = perf_event_pid(event, current);
6798 		data->tid_entry.tid = perf_event_tid(event, current);
6799 	}
6800 
6801 	if (sample_type & PERF_SAMPLE_TIME)
6802 		data->time = perf_event_clock(event);
6803 
6804 	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6805 		data->id = primary_event_id(event);
6806 
6807 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6808 		data->stream_id = event->id;
6809 
6810 	if (sample_type & PERF_SAMPLE_CPU) {
6811 		data->cpu_entry.cpu	 = raw_smp_processor_id();
6812 		data->cpu_entry.reserved = 0;
6813 	}
6814 }
6815 
perf_event_header__init_id(struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event)6816 void perf_event_header__init_id(struct perf_event_header *header,
6817 				struct perf_sample_data *data,
6818 				struct perf_event *event)
6819 {
6820 	if (event->attr.sample_id_all)
6821 		__perf_event_header__init_id(header, data, event);
6822 }
6823 
__perf_event__output_id_sample(struct perf_output_handle * handle,struct perf_sample_data * data)6824 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6825 					   struct perf_sample_data *data)
6826 {
6827 	u64 sample_type = data->type;
6828 
6829 	if (sample_type & PERF_SAMPLE_TID)
6830 		perf_output_put(handle, data->tid_entry);
6831 
6832 	if (sample_type & PERF_SAMPLE_TIME)
6833 		perf_output_put(handle, data->time);
6834 
6835 	if (sample_type & PERF_SAMPLE_ID)
6836 		perf_output_put(handle, data->id);
6837 
6838 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6839 		perf_output_put(handle, data->stream_id);
6840 
6841 	if (sample_type & PERF_SAMPLE_CPU)
6842 		perf_output_put(handle, data->cpu_entry);
6843 
6844 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
6845 		perf_output_put(handle, data->id);
6846 }
6847 
perf_event__output_id_sample(struct perf_event * event,struct perf_output_handle * handle,struct perf_sample_data * sample)6848 void perf_event__output_id_sample(struct perf_event *event,
6849 				  struct perf_output_handle *handle,
6850 				  struct perf_sample_data *sample)
6851 {
6852 	if (event->attr.sample_id_all)
6853 		__perf_event__output_id_sample(handle, sample);
6854 }
6855 
perf_output_read_one(struct perf_output_handle * handle,struct perf_event * event,u64 enabled,u64 running)6856 static void perf_output_read_one(struct perf_output_handle *handle,
6857 				 struct perf_event *event,
6858 				 u64 enabled, u64 running)
6859 {
6860 	u64 read_format = event->attr.read_format;
6861 	u64 values[4];
6862 	int n = 0;
6863 
6864 	values[n++] = perf_event_count(event);
6865 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6866 		values[n++] = enabled +
6867 			atomic64_read(&event->child_total_time_enabled);
6868 	}
6869 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6870 		values[n++] = running +
6871 			atomic64_read(&event->child_total_time_running);
6872 	}
6873 	if (read_format & PERF_FORMAT_ID)
6874 		values[n++] = primary_event_id(event);
6875 
6876 	__output_copy(handle, values, n * sizeof(u64));
6877 }
6878 
perf_output_read_group(struct perf_output_handle * handle,struct perf_event * event,u64 enabled,u64 running)6879 static void perf_output_read_group(struct perf_output_handle *handle,
6880 			    struct perf_event *event,
6881 			    u64 enabled, u64 running)
6882 {
6883 	struct perf_event *leader = event->group_leader, *sub;
6884 	u64 read_format = event->attr.read_format;
6885 	u64 values[5];
6886 	int n = 0;
6887 
6888 	values[n++] = 1 + leader->nr_siblings;
6889 
6890 	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6891 		values[n++] = enabled;
6892 
6893 	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6894 		values[n++] = running;
6895 
6896 	if ((leader != event) &&
6897 	    (leader->state == PERF_EVENT_STATE_ACTIVE))
6898 		leader->pmu->read(leader);
6899 
6900 	values[n++] = perf_event_count(leader);
6901 	if (read_format & PERF_FORMAT_ID)
6902 		values[n++] = primary_event_id(leader);
6903 
6904 	__output_copy(handle, values, n * sizeof(u64));
6905 
6906 	for_each_sibling_event(sub, leader) {
6907 		n = 0;
6908 
6909 		if ((sub != event) &&
6910 		    (sub->state == PERF_EVENT_STATE_ACTIVE))
6911 			sub->pmu->read(sub);
6912 
6913 		values[n++] = perf_event_count(sub);
6914 		if (read_format & PERF_FORMAT_ID)
6915 			values[n++] = primary_event_id(sub);
6916 
6917 		__output_copy(handle, values, n * sizeof(u64));
6918 	}
6919 }
6920 
6921 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6922 				 PERF_FORMAT_TOTAL_TIME_RUNNING)
6923 
6924 /*
6925  * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6926  *
6927  * The problem is that its both hard and excessively expensive to iterate the
6928  * child list, not to mention that its impossible to IPI the children running
6929  * on another CPU, from interrupt/NMI context.
6930  */
perf_output_read(struct perf_output_handle * handle,struct perf_event * event)6931 static void perf_output_read(struct perf_output_handle *handle,
6932 			     struct perf_event *event)
6933 {
6934 	u64 enabled = 0, running = 0, now;
6935 	u64 read_format = event->attr.read_format;
6936 
6937 	/*
6938 	 * compute total_time_enabled, total_time_running
6939 	 * based on snapshot values taken when the event
6940 	 * was last scheduled in.
6941 	 *
6942 	 * we cannot simply called update_context_time()
6943 	 * because of locking issue as we are called in
6944 	 * NMI context
6945 	 */
6946 	if (read_format & PERF_FORMAT_TOTAL_TIMES)
6947 		calc_timer_values(event, &now, &enabled, &running);
6948 
6949 	if (event->attr.read_format & PERF_FORMAT_GROUP)
6950 		perf_output_read_group(handle, event, enabled, running);
6951 	else
6952 		perf_output_read_one(handle, event, enabled, running);
6953 }
6954 
perf_sample_save_hw_index(struct perf_event * event)6955 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6956 {
6957 	return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6958 }
6959 
perf_output_sample(struct perf_output_handle * handle,struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event)6960 void perf_output_sample(struct perf_output_handle *handle,
6961 			struct perf_event_header *header,
6962 			struct perf_sample_data *data,
6963 			struct perf_event *event)
6964 {
6965 	u64 sample_type = data->type;
6966 
6967 	perf_output_put(handle, *header);
6968 
6969 	if (sample_type & PERF_SAMPLE_IDENTIFIER)
6970 		perf_output_put(handle, data->id);
6971 
6972 	if (sample_type & PERF_SAMPLE_IP)
6973 		perf_output_put(handle, data->ip);
6974 
6975 	if (sample_type & PERF_SAMPLE_TID)
6976 		perf_output_put(handle, data->tid_entry);
6977 
6978 	if (sample_type & PERF_SAMPLE_TIME)
6979 		perf_output_put(handle, data->time);
6980 
6981 	if (sample_type & PERF_SAMPLE_ADDR)
6982 		perf_output_put(handle, data->addr);
6983 
6984 	if (sample_type & PERF_SAMPLE_ID)
6985 		perf_output_put(handle, data->id);
6986 
6987 	if (sample_type & PERF_SAMPLE_STREAM_ID)
6988 		perf_output_put(handle, data->stream_id);
6989 
6990 	if (sample_type & PERF_SAMPLE_CPU)
6991 		perf_output_put(handle, data->cpu_entry);
6992 
6993 	if (sample_type & PERF_SAMPLE_PERIOD)
6994 		perf_output_put(handle, data->period);
6995 
6996 	if (sample_type & PERF_SAMPLE_READ)
6997 		perf_output_read(handle, event);
6998 
6999 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7000 		int size = 1;
7001 
7002 		size += data->callchain->nr;
7003 		size *= sizeof(u64);
7004 		__output_copy(handle, data->callchain, size);
7005 	}
7006 
7007 	if (sample_type & PERF_SAMPLE_RAW) {
7008 		struct perf_raw_record *raw = data->raw;
7009 
7010 		if (raw) {
7011 			struct perf_raw_frag *frag = &raw->frag;
7012 
7013 			perf_output_put(handle, raw->size);
7014 			do {
7015 				if (frag->copy) {
7016 					__output_custom(handle, frag->copy,
7017 							frag->data, frag->size);
7018 				} else {
7019 					__output_copy(handle, frag->data,
7020 						      frag->size);
7021 				}
7022 				if (perf_raw_frag_last(frag))
7023 					break;
7024 				frag = frag->next;
7025 			} while (1);
7026 			if (frag->pad)
7027 				__output_skip(handle, NULL, frag->pad);
7028 		} else {
7029 			struct {
7030 				u32	size;
7031 				u32	data;
7032 			} raw = {
7033 				.size = sizeof(u32),
7034 				.data = 0,
7035 			};
7036 			perf_output_put(handle, raw);
7037 		}
7038 	}
7039 
7040 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7041 		if (data->br_stack) {
7042 			size_t size;
7043 
7044 			size = data->br_stack->nr
7045 			     * sizeof(struct perf_branch_entry);
7046 
7047 			perf_output_put(handle, data->br_stack->nr);
7048 			if (perf_sample_save_hw_index(event))
7049 				perf_output_put(handle, data->br_stack->hw_idx);
7050 			perf_output_copy(handle, data->br_stack->entries, size);
7051 		} else {
7052 			/*
7053 			 * we always store at least the value of nr
7054 			 */
7055 			u64 nr = 0;
7056 			perf_output_put(handle, nr);
7057 		}
7058 	}
7059 
7060 	if (sample_type & PERF_SAMPLE_REGS_USER) {
7061 		u64 abi = data->regs_user.abi;
7062 
7063 		/*
7064 		 * If there are no regs to dump, notice it through
7065 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7066 		 */
7067 		perf_output_put(handle, abi);
7068 
7069 		if (abi) {
7070 			u64 mask = event->attr.sample_regs_user;
7071 			perf_output_sample_regs(handle,
7072 						data->regs_user.regs,
7073 						mask);
7074 		}
7075 	}
7076 
7077 	if (sample_type & PERF_SAMPLE_STACK_USER) {
7078 		perf_output_sample_ustack(handle,
7079 					  data->stack_user_size,
7080 					  data->regs_user.regs);
7081 	}
7082 
7083 	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7084 		perf_output_put(handle, data->weight.full);
7085 
7086 	if (sample_type & PERF_SAMPLE_DATA_SRC)
7087 		perf_output_put(handle, data->data_src.val);
7088 
7089 	if (sample_type & PERF_SAMPLE_TRANSACTION)
7090 		perf_output_put(handle, data->txn);
7091 
7092 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
7093 		u64 abi = data->regs_intr.abi;
7094 		/*
7095 		 * If there are no regs to dump, notice it through
7096 		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7097 		 */
7098 		perf_output_put(handle, abi);
7099 
7100 		if (abi) {
7101 			u64 mask = event->attr.sample_regs_intr;
7102 
7103 			perf_output_sample_regs(handle,
7104 						data->regs_intr.regs,
7105 						mask);
7106 		}
7107 	}
7108 
7109 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7110 		perf_output_put(handle, data->phys_addr);
7111 
7112 	if (sample_type & PERF_SAMPLE_CGROUP)
7113 		perf_output_put(handle, data->cgroup);
7114 
7115 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7116 		perf_output_put(handle, data->data_page_size);
7117 
7118 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7119 		perf_output_put(handle, data->code_page_size);
7120 
7121 	if (sample_type & PERF_SAMPLE_AUX) {
7122 		perf_output_put(handle, data->aux_size);
7123 
7124 		if (data->aux_size)
7125 			perf_aux_sample_output(event, handle, data);
7126 	}
7127 
7128 	if (!event->attr.watermark) {
7129 		int wakeup_events = event->attr.wakeup_events;
7130 
7131 		if (wakeup_events) {
7132 			struct perf_buffer *rb = handle->rb;
7133 			int events = local_inc_return(&rb->events);
7134 
7135 			if (events >= wakeup_events) {
7136 				local_sub(wakeup_events, &rb->events);
7137 				local_inc(&rb->wakeup);
7138 			}
7139 		}
7140 	}
7141 }
7142 
perf_virt_to_phys(u64 virt)7143 static u64 perf_virt_to_phys(u64 virt)
7144 {
7145 	u64 phys_addr = 0;
7146 
7147 	if (!virt)
7148 		return 0;
7149 
7150 	if (virt >= TASK_SIZE) {
7151 		/* If it's vmalloc()d memory, leave phys_addr as 0 */
7152 		if (virt_addr_valid((void *)(uintptr_t)virt) &&
7153 		    !(virt >= VMALLOC_START && virt < VMALLOC_END))
7154 			phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7155 	} else {
7156 		/*
7157 		 * Walking the pages tables for user address.
7158 		 * Interrupts are disabled, so it prevents any tear down
7159 		 * of the page tables.
7160 		 * Try IRQ-safe get_user_page_fast_only first.
7161 		 * If failed, leave phys_addr as 0.
7162 		 */
7163 		if (current->mm != NULL) {
7164 			struct page *p;
7165 
7166 			pagefault_disable();
7167 			if (get_user_page_fast_only(virt, 0, &p)) {
7168 				phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7169 				put_page(p);
7170 			}
7171 			pagefault_enable();
7172 		}
7173 	}
7174 
7175 	return phys_addr;
7176 }
7177 
7178 /*
7179  * Return the pagetable size of a given virtual address.
7180  */
perf_get_pgtable_size(struct mm_struct * mm,unsigned long addr)7181 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7182 {
7183 	u64 size = 0;
7184 
7185 #ifdef CONFIG_HAVE_FAST_GUP
7186 	pgd_t *pgdp, pgd;
7187 	p4d_t *p4dp, p4d;
7188 	pud_t *pudp, pud;
7189 	pmd_t *pmdp, pmd;
7190 	pte_t *ptep, pte;
7191 
7192 	pgdp = pgd_offset(mm, addr);
7193 	pgd = READ_ONCE(*pgdp);
7194 	if (pgd_none(pgd))
7195 		return 0;
7196 
7197 	if (pgd_leaf(pgd))
7198 		return pgd_leaf_size(pgd);
7199 
7200 	p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7201 	p4d = READ_ONCE(*p4dp);
7202 	if (!p4d_present(p4d))
7203 		return 0;
7204 
7205 	if (p4d_leaf(p4d))
7206 		return p4d_leaf_size(p4d);
7207 
7208 	pudp = pud_offset_lockless(p4dp, p4d, addr);
7209 	pud = READ_ONCE(*pudp);
7210 	if (!pud_present(pud))
7211 		return 0;
7212 
7213 	if (pud_leaf(pud))
7214 		return pud_leaf_size(pud);
7215 
7216 	pmdp = pmd_offset_lockless(pudp, pud, addr);
7217 	pmd = READ_ONCE(*pmdp);
7218 	if (!pmd_present(pmd))
7219 		return 0;
7220 
7221 	if (pmd_leaf(pmd))
7222 		return pmd_leaf_size(pmd);
7223 
7224 	ptep = pte_offset_map(&pmd, addr);
7225 	pte = ptep_get_lockless(ptep);
7226 	if (pte_present(pte))
7227 		size = pte_leaf_size(pte);
7228 	pte_unmap(ptep);
7229 #endif /* CONFIG_HAVE_FAST_GUP */
7230 
7231 	return size;
7232 }
7233 
perf_get_page_size(unsigned long addr)7234 static u64 perf_get_page_size(unsigned long addr)
7235 {
7236 	struct mm_struct *mm;
7237 	unsigned long flags;
7238 	u64 size;
7239 
7240 	if (!addr)
7241 		return 0;
7242 
7243 	/*
7244 	 * Software page-table walkers must disable IRQs,
7245 	 * which prevents any tear down of the page tables.
7246 	 */
7247 	local_irq_save(flags);
7248 
7249 	mm = current->mm;
7250 	if (!mm) {
7251 		/*
7252 		 * For kernel threads and the like, use init_mm so that
7253 		 * we can find kernel memory.
7254 		 */
7255 		mm = &init_mm;
7256 	}
7257 
7258 	size = perf_get_pgtable_size(mm, addr);
7259 
7260 	local_irq_restore(flags);
7261 
7262 	return size;
7263 }
7264 
7265 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7266 
7267 struct perf_callchain_entry *
perf_callchain(struct perf_event * event,struct pt_regs * regs)7268 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7269 {
7270 	bool kernel = !event->attr.exclude_callchain_kernel;
7271 	bool user   = !event->attr.exclude_callchain_user;
7272 	/* Disallow cross-task user callchains. */
7273 	bool crosstask = event->ctx->task && event->ctx->task != current;
7274 	const u32 max_stack = event->attr.sample_max_stack;
7275 	struct perf_callchain_entry *callchain;
7276 
7277 	if (!kernel && !user)
7278 		return &__empty_callchain;
7279 
7280 	callchain = get_perf_callchain(regs, 0, kernel, user,
7281 				       max_stack, crosstask, true);
7282 	return callchain ?: &__empty_callchain;
7283 }
7284 
perf_prepare_sample(struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event,struct pt_regs * regs)7285 void perf_prepare_sample(struct perf_event_header *header,
7286 			 struct perf_sample_data *data,
7287 			 struct perf_event *event,
7288 			 struct pt_regs *regs)
7289 {
7290 	u64 sample_type = event->attr.sample_type;
7291 
7292 	header->type = PERF_RECORD_SAMPLE;
7293 	header->size = sizeof(*header) + event->header_size;
7294 
7295 	header->misc = 0;
7296 	header->misc |= perf_misc_flags(regs);
7297 
7298 	__perf_event_header__init_id(header, data, event);
7299 
7300 	if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7301 		data->ip = perf_instruction_pointer(regs);
7302 
7303 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7304 		int size = 1;
7305 
7306 		if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7307 			data->callchain = perf_callchain(event, regs);
7308 
7309 		size += data->callchain->nr;
7310 
7311 		header->size += size * sizeof(u64);
7312 	}
7313 
7314 	if (sample_type & PERF_SAMPLE_RAW) {
7315 		struct perf_raw_record *raw = data->raw;
7316 		int size;
7317 
7318 		if (raw) {
7319 			struct perf_raw_frag *frag = &raw->frag;
7320 			u32 sum = 0;
7321 
7322 			do {
7323 				sum += frag->size;
7324 				if (perf_raw_frag_last(frag))
7325 					break;
7326 				frag = frag->next;
7327 			} while (1);
7328 
7329 			size = round_up(sum + sizeof(u32), sizeof(u64));
7330 			raw->size = size - sizeof(u32);
7331 			frag->pad = raw->size - sum;
7332 		} else {
7333 			size = sizeof(u64);
7334 		}
7335 
7336 		header->size += size;
7337 	}
7338 
7339 	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7340 		int size = sizeof(u64); /* nr */
7341 		if (data->br_stack) {
7342 			if (perf_sample_save_hw_index(event))
7343 				size += sizeof(u64);
7344 
7345 			size += data->br_stack->nr
7346 			      * sizeof(struct perf_branch_entry);
7347 		}
7348 		header->size += size;
7349 	}
7350 
7351 	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7352 		perf_sample_regs_user(&data->regs_user, regs);
7353 
7354 	if (sample_type & PERF_SAMPLE_REGS_USER) {
7355 		/* regs dump ABI info */
7356 		int size = sizeof(u64);
7357 
7358 		if (data->regs_user.regs) {
7359 			u64 mask = event->attr.sample_regs_user;
7360 			size += hweight64(mask) * sizeof(u64);
7361 		}
7362 
7363 		header->size += size;
7364 	}
7365 
7366 	if (sample_type & PERF_SAMPLE_STACK_USER) {
7367 		/*
7368 		 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7369 		 * processed as the last one or have additional check added
7370 		 * in case new sample type is added, because we could eat
7371 		 * up the rest of the sample size.
7372 		 */
7373 		u16 stack_size = event->attr.sample_stack_user;
7374 		u16 size = sizeof(u64);
7375 
7376 		stack_size = perf_sample_ustack_size(stack_size, header->size,
7377 						     data->regs_user.regs);
7378 
7379 		/*
7380 		 * If there is something to dump, add space for the dump
7381 		 * itself and for the field that tells the dynamic size,
7382 		 * which is how many have been actually dumped.
7383 		 */
7384 		if (stack_size)
7385 			size += sizeof(u64) + stack_size;
7386 
7387 		data->stack_user_size = stack_size;
7388 		header->size += size;
7389 	}
7390 
7391 	if (sample_type & PERF_SAMPLE_REGS_INTR) {
7392 		/* regs dump ABI info */
7393 		int size = sizeof(u64);
7394 
7395 		perf_sample_regs_intr(&data->regs_intr, regs);
7396 
7397 		if (data->regs_intr.regs) {
7398 			u64 mask = event->attr.sample_regs_intr;
7399 
7400 			size += hweight64(mask) * sizeof(u64);
7401 		}
7402 
7403 		header->size += size;
7404 	}
7405 
7406 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7407 		data->phys_addr = perf_virt_to_phys(data->addr);
7408 
7409 #ifdef CONFIG_CGROUP_PERF
7410 	if (sample_type & PERF_SAMPLE_CGROUP) {
7411 		struct cgroup *cgrp;
7412 
7413 		/* protected by RCU */
7414 		cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7415 		data->cgroup = cgroup_id(cgrp);
7416 	}
7417 #endif
7418 
7419 	/*
7420 	 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7421 	 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7422 	 * but the value will not dump to the userspace.
7423 	 */
7424 	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7425 		data->data_page_size = perf_get_page_size(data->addr);
7426 
7427 	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7428 		data->code_page_size = perf_get_page_size(data->ip);
7429 
7430 	if (sample_type & PERF_SAMPLE_AUX) {
7431 		u64 size;
7432 
7433 		header->size += sizeof(u64); /* size */
7434 
7435 		/*
7436 		 * Given the 16bit nature of header::size, an AUX sample can
7437 		 * easily overflow it, what with all the preceding sample bits.
7438 		 * Make sure this doesn't happen by using up to U16_MAX bytes
7439 		 * per sample in total (rounded down to 8 byte boundary).
7440 		 */
7441 		size = min_t(size_t, U16_MAX - header->size,
7442 			     event->attr.aux_sample_size);
7443 		size = rounddown(size, 8);
7444 		size = perf_prepare_sample_aux(event, data, size);
7445 
7446 		WARN_ON_ONCE(size + header->size > U16_MAX);
7447 		header->size += size;
7448 	}
7449 	/*
7450 	 * If you're adding more sample types here, you likely need to do
7451 	 * something about the overflowing header::size, like repurpose the
7452 	 * lowest 3 bits of size, which should be always zero at the moment.
7453 	 * This raises a more important question, do we really need 512k sized
7454 	 * samples and why, so good argumentation is in order for whatever you
7455 	 * do here next.
7456 	 */
7457 	WARN_ON_ONCE(header->size & 7);
7458 }
7459 
7460 static __always_inline int
__perf_event_output(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs,int (* output_begin)(struct perf_output_handle *,struct perf_sample_data *,struct perf_event *,unsigned int))7461 __perf_event_output(struct perf_event *event,
7462 		    struct perf_sample_data *data,
7463 		    struct pt_regs *regs,
7464 		    int (*output_begin)(struct perf_output_handle *,
7465 					struct perf_sample_data *,
7466 					struct perf_event *,
7467 					unsigned int))
7468 {
7469 	struct perf_output_handle handle;
7470 	struct perf_event_header header;
7471 	int err;
7472 
7473 	/* protect the callchain buffers */
7474 	rcu_read_lock();
7475 
7476 	perf_prepare_sample(&header, data, event, regs);
7477 
7478 	err = output_begin(&handle, data, event, header.size);
7479 	if (err)
7480 		goto exit;
7481 
7482 	perf_output_sample(&handle, &header, data, event);
7483 
7484 	perf_output_end(&handle);
7485 
7486 exit:
7487 	rcu_read_unlock();
7488 	return err;
7489 }
7490 
7491 void
perf_event_output_forward(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7492 perf_event_output_forward(struct perf_event *event,
7493 			 struct perf_sample_data *data,
7494 			 struct pt_regs *regs)
7495 {
7496 	__perf_event_output(event, data, regs, perf_output_begin_forward);
7497 }
7498 
7499 void
perf_event_output_backward(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7500 perf_event_output_backward(struct perf_event *event,
7501 			   struct perf_sample_data *data,
7502 			   struct pt_regs *regs)
7503 {
7504 	__perf_event_output(event, data, regs, perf_output_begin_backward);
7505 }
7506 
7507 int
perf_event_output(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7508 perf_event_output(struct perf_event *event,
7509 		  struct perf_sample_data *data,
7510 		  struct pt_regs *regs)
7511 {
7512 	return __perf_event_output(event, data, regs, perf_output_begin);
7513 }
7514 
7515 /*
7516  * read event_id
7517  */
7518 
7519 struct perf_read_event {
7520 	struct perf_event_header	header;
7521 
7522 	u32				pid;
7523 	u32				tid;
7524 };
7525 
7526 static void
perf_event_read_event(struct perf_event * event,struct task_struct * task)7527 perf_event_read_event(struct perf_event *event,
7528 			struct task_struct *task)
7529 {
7530 	struct perf_output_handle handle;
7531 	struct perf_sample_data sample;
7532 	struct perf_read_event read_event = {
7533 		.header = {
7534 			.type = PERF_RECORD_READ,
7535 			.misc = 0,
7536 			.size = sizeof(read_event) + event->read_size,
7537 		},
7538 		.pid = perf_event_pid(event, task),
7539 		.tid = perf_event_tid(event, task),
7540 	};
7541 	int ret;
7542 
7543 	perf_event_header__init_id(&read_event.header, &sample, event);
7544 	ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7545 	if (ret)
7546 		return;
7547 
7548 	perf_output_put(&handle, read_event);
7549 	perf_output_read(&handle, event);
7550 	perf_event__output_id_sample(event, &handle, &sample);
7551 
7552 	perf_output_end(&handle);
7553 }
7554 
7555 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7556 
7557 static void
perf_iterate_ctx(struct perf_event_context * ctx,perf_iterate_f output,void * data,bool all)7558 perf_iterate_ctx(struct perf_event_context *ctx,
7559 		   perf_iterate_f output,
7560 		   void *data, bool all)
7561 {
7562 	struct perf_event *event;
7563 
7564 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7565 		if (!all) {
7566 			if (event->state < PERF_EVENT_STATE_INACTIVE)
7567 				continue;
7568 			if (!event_filter_match(event))
7569 				continue;
7570 		}
7571 
7572 		output(event, data);
7573 	}
7574 }
7575 
perf_iterate_sb_cpu(perf_iterate_f output,void * data)7576 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7577 {
7578 	struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7579 	struct perf_event *event;
7580 
7581 	list_for_each_entry_rcu(event, &pel->list, sb_list) {
7582 		/*
7583 		 * Skip events that are not fully formed yet; ensure that
7584 		 * if we observe event->ctx, both event and ctx will be
7585 		 * complete enough. See perf_install_in_context().
7586 		 */
7587 		if (!smp_load_acquire(&event->ctx))
7588 			continue;
7589 
7590 		if (event->state < PERF_EVENT_STATE_INACTIVE)
7591 			continue;
7592 		if (!event_filter_match(event))
7593 			continue;
7594 		output(event, data);
7595 	}
7596 }
7597 
7598 /*
7599  * Iterate all events that need to receive side-band events.
7600  *
7601  * For new callers; ensure that account_pmu_sb_event() includes
7602  * your event, otherwise it might not get delivered.
7603  */
7604 static void
perf_iterate_sb(perf_iterate_f output,void * data,struct perf_event_context * task_ctx)7605 perf_iterate_sb(perf_iterate_f output, void *data,
7606 	       struct perf_event_context *task_ctx)
7607 {
7608 	struct perf_event_context *ctx;
7609 	int ctxn;
7610 
7611 	rcu_read_lock();
7612 	preempt_disable();
7613 
7614 	/*
7615 	 * If we have task_ctx != NULL we only notify the task context itself.
7616 	 * The task_ctx is set only for EXIT events before releasing task
7617 	 * context.
7618 	 */
7619 	if (task_ctx) {
7620 		perf_iterate_ctx(task_ctx, output, data, false);
7621 		goto done;
7622 	}
7623 
7624 	perf_iterate_sb_cpu(output, data);
7625 
7626 	for_each_task_context_nr(ctxn) {
7627 		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7628 		if (ctx)
7629 			perf_iterate_ctx(ctx, output, data, false);
7630 	}
7631 done:
7632 	preempt_enable();
7633 	rcu_read_unlock();
7634 }
7635 
7636 /*
7637  * Clear all file-based filters at exec, they'll have to be
7638  * re-instated when/if these objects are mmapped again.
7639  */
perf_event_addr_filters_exec(struct perf_event * event,void * data)7640 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7641 {
7642 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7643 	struct perf_addr_filter *filter;
7644 	unsigned int restart = 0, count = 0;
7645 	unsigned long flags;
7646 
7647 	if (!has_addr_filter(event))
7648 		return;
7649 
7650 	raw_spin_lock_irqsave(&ifh->lock, flags);
7651 	list_for_each_entry(filter, &ifh->list, entry) {
7652 		if (filter->path.dentry) {
7653 			event->addr_filter_ranges[count].start = 0;
7654 			event->addr_filter_ranges[count].size = 0;
7655 			restart++;
7656 		}
7657 
7658 		count++;
7659 	}
7660 
7661 	if (restart)
7662 		event->addr_filters_gen++;
7663 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
7664 
7665 	if (restart)
7666 		perf_event_stop(event, 1);
7667 }
7668 
perf_event_exec(void)7669 void perf_event_exec(void)
7670 {
7671 	struct perf_event_context *ctx;
7672 	int ctxn;
7673 
7674 	for_each_task_context_nr(ctxn) {
7675 		perf_event_enable_on_exec(ctxn);
7676 		perf_event_remove_on_exec(ctxn);
7677 
7678 		rcu_read_lock();
7679 		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7680 		if (ctx) {
7681 			perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7682 					 NULL, true);
7683 		}
7684 		rcu_read_unlock();
7685 	}
7686 }
7687 
7688 struct remote_output {
7689 	struct perf_buffer	*rb;
7690 	int			err;
7691 };
7692 
__perf_event_output_stop(struct perf_event * event,void * data)7693 static void __perf_event_output_stop(struct perf_event *event, void *data)
7694 {
7695 	struct perf_event *parent = event->parent;
7696 	struct remote_output *ro = data;
7697 	struct perf_buffer *rb = ro->rb;
7698 	struct stop_event_data sd = {
7699 		.event	= event,
7700 	};
7701 
7702 	if (!has_aux(event))
7703 		return;
7704 
7705 	if (!parent)
7706 		parent = event;
7707 
7708 	/*
7709 	 * In case of inheritance, it will be the parent that links to the
7710 	 * ring-buffer, but it will be the child that's actually using it.
7711 	 *
7712 	 * We are using event::rb to determine if the event should be stopped,
7713 	 * however this may race with ring_buffer_attach() (through set_output),
7714 	 * which will make us skip the event that actually needs to be stopped.
7715 	 * So ring_buffer_attach() has to stop an aux event before re-assigning
7716 	 * its rb pointer.
7717 	 */
7718 	if (rcu_dereference(parent->rb) == rb)
7719 		ro->err = __perf_event_stop(&sd);
7720 }
7721 
__perf_pmu_output_stop(void * info)7722 static int __perf_pmu_output_stop(void *info)
7723 {
7724 	struct perf_event *event = info;
7725 	struct pmu *pmu = event->ctx->pmu;
7726 	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7727 	struct remote_output ro = {
7728 		.rb	= event->rb,
7729 	};
7730 
7731 	rcu_read_lock();
7732 	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7733 	if (cpuctx->task_ctx)
7734 		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7735 				   &ro, false);
7736 	rcu_read_unlock();
7737 
7738 	return ro.err;
7739 }
7740 
perf_pmu_output_stop(struct perf_event * event)7741 static void perf_pmu_output_stop(struct perf_event *event)
7742 {
7743 	struct perf_event *iter;
7744 	int err, cpu;
7745 
7746 restart:
7747 	rcu_read_lock();
7748 	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7749 		/*
7750 		 * For per-CPU events, we need to make sure that neither they
7751 		 * nor their children are running; for cpu==-1 events it's
7752 		 * sufficient to stop the event itself if it's active, since
7753 		 * it can't have children.
7754 		 */
7755 		cpu = iter->cpu;
7756 		if (cpu == -1)
7757 			cpu = READ_ONCE(iter->oncpu);
7758 
7759 		if (cpu == -1)
7760 			continue;
7761 
7762 		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7763 		if (err == -EAGAIN) {
7764 			rcu_read_unlock();
7765 			goto restart;
7766 		}
7767 	}
7768 	rcu_read_unlock();
7769 }
7770 
7771 /*
7772  * task tracking -- fork/exit
7773  *
7774  * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7775  */
7776 
7777 struct perf_task_event {
7778 	struct task_struct		*task;
7779 	struct perf_event_context	*task_ctx;
7780 
7781 	struct {
7782 		struct perf_event_header	header;
7783 
7784 		u32				pid;
7785 		u32				ppid;
7786 		u32				tid;
7787 		u32				ptid;
7788 		u64				time;
7789 	} event_id;
7790 };
7791 
perf_event_task_match(struct perf_event * event)7792 static int perf_event_task_match(struct perf_event *event)
7793 {
7794 	return event->attr.comm  || event->attr.mmap ||
7795 	       event->attr.mmap2 || event->attr.mmap_data ||
7796 	       event->attr.task;
7797 }
7798 
perf_event_task_output(struct perf_event * event,void * data)7799 static void perf_event_task_output(struct perf_event *event,
7800 				   void *data)
7801 {
7802 	struct perf_task_event *task_event = data;
7803 	struct perf_output_handle handle;
7804 	struct perf_sample_data	sample;
7805 	struct task_struct *task = task_event->task;
7806 	int ret, size = task_event->event_id.header.size;
7807 
7808 	if (!perf_event_task_match(event))
7809 		return;
7810 
7811 	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7812 
7813 	ret = perf_output_begin(&handle, &sample, event,
7814 				task_event->event_id.header.size);
7815 	if (ret)
7816 		goto out;
7817 
7818 	task_event->event_id.pid = perf_event_pid(event, task);
7819 	task_event->event_id.tid = perf_event_tid(event, task);
7820 
7821 	if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7822 		task_event->event_id.ppid = perf_event_pid(event,
7823 							task->real_parent);
7824 		task_event->event_id.ptid = perf_event_pid(event,
7825 							task->real_parent);
7826 	} else {  /* PERF_RECORD_FORK */
7827 		task_event->event_id.ppid = perf_event_pid(event, current);
7828 		task_event->event_id.ptid = perf_event_tid(event, current);
7829 	}
7830 
7831 	task_event->event_id.time = perf_event_clock(event);
7832 
7833 	perf_output_put(&handle, task_event->event_id);
7834 
7835 	perf_event__output_id_sample(event, &handle, &sample);
7836 
7837 	perf_output_end(&handle);
7838 out:
7839 	task_event->event_id.header.size = size;
7840 }
7841 
perf_event_task(struct task_struct * task,struct perf_event_context * task_ctx,int new)7842 static void perf_event_task(struct task_struct *task,
7843 			      struct perf_event_context *task_ctx,
7844 			      int new)
7845 {
7846 	struct perf_task_event task_event;
7847 
7848 	if (!atomic_read(&nr_comm_events) &&
7849 	    !atomic_read(&nr_mmap_events) &&
7850 	    !atomic_read(&nr_task_events))
7851 		return;
7852 
7853 	task_event = (struct perf_task_event){
7854 		.task	  = task,
7855 		.task_ctx = task_ctx,
7856 		.event_id    = {
7857 			.header = {
7858 				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7859 				.misc = 0,
7860 				.size = sizeof(task_event.event_id),
7861 			},
7862 			/* .pid  */
7863 			/* .ppid */
7864 			/* .tid  */
7865 			/* .ptid */
7866 			/* .time */
7867 		},
7868 	};
7869 
7870 	perf_iterate_sb(perf_event_task_output,
7871 		       &task_event,
7872 		       task_ctx);
7873 }
7874 
perf_event_fork(struct task_struct * task)7875 void perf_event_fork(struct task_struct *task)
7876 {
7877 	perf_event_task(task, NULL, 1);
7878 	perf_event_namespaces(task);
7879 }
7880 
7881 /*
7882  * comm tracking
7883  */
7884 
7885 struct perf_comm_event {
7886 	struct task_struct	*task;
7887 	char			*comm;
7888 	int			comm_size;
7889 
7890 	struct {
7891 		struct perf_event_header	header;
7892 
7893 		u32				pid;
7894 		u32				tid;
7895 	} event_id;
7896 };
7897 
perf_event_comm_match(struct perf_event * event)7898 static int perf_event_comm_match(struct perf_event *event)
7899 {
7900 	return event->attr.comm;
7901 }
7902 
perf_event_comm_output(struct perf_event * event,void * data)7903 static void perf_event_comm_output(struct perf_event *event,
7904 				   void *data)
7905 {
7906 	struct perf_comm_event *comm_event = data;
7907 	struct perf_output_handle handle;
7908 	struct perf_sample_data sample;
7909 	int size = comm_event->event_id.header.size;
7910 	int ret;
7911 
7912 	if (!perf_event_comm_match(event))
7913 		return;
7914 
7915 	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7916 	ret = perf_output_begin(&handle, &sample, event,
7917 				comm_event->event_id.header.size);
7918 
7919 	if (ret)
7920 		goto out;
7921 
7922 	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7923 	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7924 
7925 	perf_output_put(&handle, comm_event->event_id);
7926 	__output_copy(&handle, comm_event->comm,
7927 				   comm_event->comm_size);
7928 
7929 	perf_event__output_id_sample(event, &handle, &sample);
7930 
7931 	perf_output_end(&handle);
7932 out:
7933 	comm_event->event_id.header.size = size;
7934 }
7935 
perf_event_comm_event(struct perf_comm_event * comm_event)7936 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7937 {
7938 	char comm[TASK_COMM_LEN];
7939 	unsigned int size;
7940 
7941 	memset(comm, 0, sizeof(comm));
7942 	strlcpy(comm, comm_event->task->comm, sizeof(comm));
7943 	size = ALIGN(strlen(comm)+1, sizeof(u64));
7944 
7945 	comm_event->comm = comm;
7946 	comm_event->comm_size = size;
7947 
7948 	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7949 
7950 	perf_iterate_sb(perf_event_comm_output,
7951 		       comm_event,
7952 		       NULL);
7953 }
7954 
perf_event_comm(struct task_struct * task,bool exec)7955 void perf_event_comm(struct task_struct *task, bool exec)
7956 {
7957 	struct perf_comm_event comm_event;
7958 
7959 	if (!atomic_read(&nr_comm_events))
7960 		return;
7961 
7962 	comm_event = (struct perf_comm_event){
7963 		.task	= task,
7964 		/* .comm      */
7965 		/* .comm_size */
7966 		.event_id  = {
7967 			.header = {
7968 				.type = PERF_RECORD_COMM,
7969 				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7970 				/* .size */
7971 			},
7972 			/* .pid */
7973 			/* .tid */
7974 		},
7975 	};
7976 
7977 	perf_event_comm_event(&comm_event);
7978 }
7979 
7980 /*
7981  * namespaces tracking
7982  */
7983 
7984 struct perf_namespaces_event {
7985 	struct task_struct		*task;
7986 
7987 	struct {
7988 		struct perf_event_header	header;
7989 
7990 		u32				pid;
7991 		u32				tid;
7992 		u64				nr_namespaces;
7993 		struct perf_ns_link_info	link_info[NR_NAMESPACES];
7994 	} event_id;
7995 };
7996 
perf_event_namespaces_match(struct perf_event * event)7997 static int perf_event_namespaces_match(struct perf_event *event)
7998 {
7999 	return event->attr.namespaces;
8000 }
8001 
perf_event_namespaces_output(struct perf_event * event,void * data)8002 static void perf_event_namespaces_output(struct perf_event *event,
8003 					 void *data)
8004 {
8005 	struct perf_namespaces_event *namespaces_event = data;
8006 	struct perf_output_handle handle;
8007 	struct perf_sample_data sample;
8008 	u16 header_size = namespaces_event->event_id.header.size;
8009 	int ret;
8010 
8011 	if (!perf_event_namespaces_match(event))
8012 		return;
8013 
8014 	perf_event_header__init_id(&namespaces_event->event_id.header,
8015 				   &sample, event);
8016 	ret = perf_output_begin(&handle, &sample, event,
8017 				namespaces_event->event_id.header.size);
8018 	if (ret)
8019 		goto out;
8020 
8021 	namespaces_event->event_id.pid = perf_event_pid(event,
8022 							namespaces_event->task);
8023 	namespaces_event->event_id.tid = perf_event_tid(event,
8024 							namespaces_event->task);
8025 
8026 	perf_output_put(&handle, namespaces_event->event_id);
8027 
8028 	perf_event__output_id_sample(event, &handle, &sample);
8029 
8030 	perf_output_end(&handle);
8031 out:
8032 	namespaces_event->event_id.header.size = header_size;
8033 }
8034 
perf_fill_ns_link_info(struct perf_ns_link_info * ns_link_info,struct task_struct * task,const struct proc_ns_operations * ns_ops)8035 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8036 				   struct task_struct *task,
8037 				   const struct proc_ns_operations *ns_ops)
8038 {
8039 	struct path ns_path;
8040 	struct inode *ns_inode;
8041 	int error;
8042 
8043 	error = ns_get_path(&ns_path, task, ns_ops);
8044 	if (!error) {
8045 		ns_inode = ns_path.dentry->d_inode;
8046 		ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8047 		ns_link_info->ino = ns_inode->i_ino;
8048 		path_put(&ns_path);
8049 	}
8050 }
8051 
perf_event_namespaces(struct task_struct * task)8052 void perf_event_namespaces(struct task_struct *task)
8053 {
8054 	struct perf_namespaces_event namespaces_event;
8055 	struct perf_ns_link_info *ns_link_info;
8056 
8057 	if (!atomic_read(&nr_namespaces_events))
8058 		return;
8059 
8060 	namespaces_event = (struct perf_namespaces_event){
8061 		.task	= task,
8062 		.event_id  = {
8063 			.header = {
8064 				.type = PERF_RECORD_NAMESPACES,
8065 				.misc = 0,
8066 				.size = sizeof(namespaces_event.event_id),
8067 			},
8068 			/* .pid */
8069 			/* .tid */
8070 			.nr_namespaces = NR_NAMESPACES,
8071 			/* .link_info[NR_NAMESPACES] */
8072 		},
8073 	};
8074 
8075 	ns_link_info = namespaces_event.event_id.link_info;
8076 
8077 	perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8078 			       task, &mntns_operations);
8079 
8080 #ifdef CONFIG_USER_NS
8081 	perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8082 			       task, &userns_operations);
8083 #endif
8084 #ifdef CONFIG_NET_NS
8085 	perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8086 			       task, &netns_operations);
8087 #endif
8088 #ifdef CONFIG_UTS_NS
8089 	perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8090 			       task, &utsns_operations);
8091 #endif
8092 #ifdef CONFIG_IPC_NS
8093 	perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8094 			       task, &ipcns_operations);
8095 #endif
8096 #ifdef CONFIG_PID_NS
8097 	perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8098 			       task, &pidns_operations);
8099 #endif
8100 #ifdef CONFIG_CGROUPS
8101 	perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8102 			       task, &cgroupns_operations);
8103 #endif
8104 
8105 	perf_iterate_sb(perf_event_namespaces_output,
8106 			&namespaces_event,
8107 			NULL);
8108 }
8109 
8110 /*
8111  * cgroup tracking
8112  */
8113 #ifdef CONFIG_CGROUP_PERF
8114 
8115 struct perf_cgroup_event {
8116 	char				*path;
8117 	int				path_size;
8118 	struct {
8119 		struct perf_event_header	header;
8120 		u64				id;
8121 		char				path[];
8122 	} event_id;
8123 };
8124 
perf_event_cgroup_match(struct perf_event * event)8125 static int perf_event_cgroup_match(struct perf_event *event)
8126 {
8127 	return event->attr.cgroup;
8128 }
8129 
perf_event_cgroup_output(struct perf_event * event,void * data)8130 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8131 {
8132 	struct perf_cgroup_event *cgroup_event = data;
8133 	struct perf_output_handle handle;
8134 	struct perf_sample_data sample;
8135 	u16 header_size = cgroup_event->event_id.header.size;
8136 	int ret;
8137 
8138 	if (!perf_event_cgroup_match(event))
8139 		return;
8140 
8141 	perf_event_header__init_id(&cgroup_event->event_id.header,
8142 				   &sample, event);
8143 	ret = perf_output_begin(&handle, &sample, event,
8144 				cgroup_event->event_id.header.size);
8145 	if (ret)
8146 		goto out;
8147 
8148 	perf_output_put(&handle, cgroup_event->event_id);
8149 	__output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8150 
8151 	perf_event__output_id_sample(event, &handle, &sample);
8152 
8153 	perf_output_end(&handle);
8154 out:
8155 	cgroup_event->event_id.header.size = header_size;
8156 }
8157 
perf_event_cgroup(struct cgroup * cgrp)8158 static void perf_event_cgroup(struct cgroup *cgrp)
8159 {
8160 	struct perf_cgroup_event cgroup_event;
8161 	char path_enomem[16] = "//enomem";
8162 	char *pathname;
8163 	size_t size;
8164 
8165 	if (!atomic_read(&nr_cgroup_events))
8166 		return;
8167 
8168 	cgroup_event = (struct perf_cgroup_event){
8169 		.event_id  = {
8170 			.header = {
8171 				.type = PERF_RECORD_CGROUP,
8172 				.misc = 0,
8173 				.size = sizeof(cgroup_event.event_id),
8174 			},
8175 			.id = cgroup_id(cgrp),
8176 		},
8177 	};
8178 
8179 	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8180 	if (pathname == NULL) {
8181 		cgroup_event.path = path_enomem;
8182 	} else {
8183 		/* just to be sure to have enough space for alignment */
8184 		cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8185 		cgroup_event.path = pathname;
8186 	}
8187 
8188 	/*
8189 	 * Since our buffer works in 8 byte units we need to align our string
8190 	 * size to a multiple of 8. However, we must guarantee the tail end is
8191 	 * zero'd out to avoid leaking random bits to userspace.
8192 	 */
8193 	size = strlen(cgroup_event.path) + 1;
8194 	while (!IS_ALIGNED(size, sizeof(u64)))
8195 		cgroup_event.path[size++] = '\0';
8196 
8197 	cgroup_event.event_id.header.size += size;
8198 	cgroup_event.path_size = size;
8199 
8200 	perf_iterate_sb(perf_event_cgroup_output,
8201 			&cgroup_event,
8202 			NULL);
8203 
8204 	kfree(pathname);
8205 }
8206 
8207 #endif
8208 
8209 /*
8210  * mmap tracking
8211  */
8212 
8213 struct perf_mmap_event {
8214 	struct vm_area_struct	*vma;
8215 
8216 	const char		*file_name;
8217 	int			file_size;
8218 	int			maj, min;
8219 	u64			ino;
8220 	u64			ino_generation;
8221 	u32			prot, flags;
8222 	u8			build_id[BUILD_ID_SIZE_MAX];
8223 	u32			build_id_size;
8224 
8225 	struct {
8226 		struct perf_event_header	header;
8227 
8228 		u32				pid;
8229 		u32				tid;
8230 		u64				start;
8231 		u64				len;
8232 		u64				pgoff;
8233 	} event_id;
8234 };
8235 
perf_event_mmap_match(struct perf_event * event,void * data)8236 static int perf_event_mmap_match(struct perf_event *event,
8237 				 void *data)
8238 {
8239 	struct perf_mmap_event *mmap_event = data;
8240 	struct vm_area_struct *vma = mmap_event->vma;
8241 	int executable = vma->vm_flags & VM_EXEC;
8242 
8243 	return (!executable && event->attr.mmap_data) ||
8244 	       (executable && (event->attr.mmap || event->attr.mmap2));
8245 }
8246 
perf_event_mmap_output(struct perf_event * event,void * data)8247 static void perf_event_mmap_output(struct perf_event *event,
8248 				   void *data)
8249 {
8250 	struct perf_mmap_event *mmap_event = data;
8251 	struct perf_output_handle handle;
8252 	struct perf_sample_data sample;
8253 	int size = mmap_event->event_id.header.size;
8254 	u32 type = mmap_event->event_id.header.type;
8255 	bool use_build_id;
8256 	int ret;
8257 
8258 	if (!perf_event_mmap_match(event, data))
8259 		return;
8260 
8261 	if (event->attr.mmap2) {
8262 		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8263 		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8264 		mmap_event->event_id.header.size += sizeof(mmap_event->min);
8265 		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8266 		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8267 		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8268 		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8269 	}
8270 
8271 	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8272 	ret = perf_output_begin(&handle, &sample, event,
8273 				mmap_event->event_id.header.size);
8274 	if (ret)
8275 		goto out;
8276 
8277 	mmap_event->event_id.pid = perf_event_pid(event, current);
8278 	mmap_event->event_id.tid = perf_event_tid(event, current);
8279 
8280 	use_build_id = event->attr.build_id && mmap_event->build_id_size;
8281 
8282 	if (event->attr.mmap2 && use_build_id)
8283 		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8284 
8285 	perf_output_put(&handle, mmap_event->event_id);
8286 
8287 	if (event->attr.mmap2) {
8288 		if (use_build_id) {
8289 			u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8290 
8291 			__output_copy(&handle, size, 4);
8292 			__output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8293 		} else {
8294 			perf_output_put(&handle, mmap_event->maj);
8295 			perf_output_put(&handle, mmap_event->min);
8296 			perf_output_put(&handle, mmap_event->ino);
8297 			perf_output_put(&handle, mmap_event->ino_generation);
8298 		}
8299 		perf_output_put(&handle, mmap_event->prot);
8300 		perf_output_put(&handle, mmap_event->flags);
8301 	}
8302 
8303 	__output_copy(&handle, mmap_event->file_name,
8304 				   mmap_event->file_size);
8305 
8306 	perf_event__output_id_sample(event, &handle, &sample);
8307 
8308 	perf_output_end(&handle);
8309 out:
8310 	mmap_event->event_id.header.size = size;
8311 	mmap_event->event_id.header.type = type;
8312 }
8313 
perf_event_mmap_event(struct perf_mmap_event * mmap_event)8314 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8315 {
8316 	struct vm_area_struct *vma = mmap_event->vma;
8317 	struct file *file = vma->vm_file;
8318 	int maj = 0, min = 0;
8319 	u64 ino = 0, gen = 0;
8320 	u32 prot = 0, flags = 0;
8321 	unsigned int size;
8322 	char tmp[16];
8323 	char *buf = NULL;
8324 	char *name;
8325 
8326 	if (vma->vm_flags & VM_READ)
8327 		prot |= PROT_READ;
8328 	if (vma->vm_flags & VM_WRITE)
8329 		prot |= PROT_WRITE;
8330 	if (vma->vm_flags & VM_EXEC)
8331 		prot |= PROT_EXEC;
8332 
8333 	if (vma->vm_flags & VM_MAYSHARE)
8334 		flags = MAP_SHARED;
8335 	else
8336 		flags = MAP_PRIVATE;
8337 
8338 	if (vma->vm_flags & VM_LOCKED)
8339 		flags |= MAP_LOCKED;
8340 	if (is_vm_hugetlb_page(vma))
8341 		flags |= MAP_HUGETLB;
8342 
8343 	if (file) {
8344 		struct inode *inode;
8345 		dev_t dev;
8346 
8347 		buf = kmalloc(PATH_MAX, GFP_KERNEL);
8348 		if (!buf) {
8349 			name = "//enomem";
8350 			goto cpy_name;
8351 		}
8352 		/*
8353 		 * d_path() works from the end of the rb backwards, so we
8354 		 * need to add enough zero bytes after the string to handle
8355 		 * the 64bit alignment we do later.
8356 		 */
8357 		name = file_path(file, buf, PATH_MAX - sizeof(u64));
8358 		if (IS_ERR(name)) {
8359 			name = "//toolong";
8360 			goto cpy_name;
8361 		}
8362 		inode = file_inode(vma->vm_file);
8363 		dev = inode->i_sb->s_dev;
8364 		ino = inode->i_ino;
8365 		gen = inode->i_generation;
8366 		maj = MAJOR(dev);
8367 		min = MINOR(dev);
8368 
8369 		goto got_name;
8370 	} else {
8371 		if (vma->vm_ops && vma->vm_ops->name) {
8372 			name = (char *) vma->vm_ops->name(vma);
8373 			if (name)
8374 				goto cpy_name;
8375 		}
8376 
8377 		name = (char *)arch_vma_name(vma);
8378 		if (name)
8379 			goto cpy_name;
8380 
8381 		if (vma->vm_start <= vma->vm_mm->start_brk &&
8382 				vma->vm_end >= vma->vm_mm->brk) {
8383 			name = "[heap]";
8384 			goto cpy_name;
8385 		}
8386 		if (vma->vm_start <= vma->vm_mm->start_stack &&
8387 				vma->vm_end >= vma->vm_mm->start_stack) {
8388 			name = "[stack]";
8389 			goto cpy_name;
8390 		}
8391 
8392 		name = "//anon";
8393 		goto cpy_name;
8394 	}
8395 
8396 cpy_name:
8397 	strlcpy(tmp, name, sizeof(tmp));
8398 	name = tmp;
8399 got_name:
8400 	/*
8401 	 * Since our buffer works in 8 byte units we need to align our string
8402 	 * size to a multiple of 8. However, we must guarantee the tail end is
8403 	 * zero'd out to avoid leaking random bits to userspace.
8404 	 */
8405 	size = strlen(name)+1;
8406 	while (!IS_ALIGNED(size, sizeof(u64)))
8407 		name[size++] = '\0';
8408 
8409 	mmap_event->file_name = name;
8410 	mmap_event->file_size = size;
8411 	mmap_event->maj = maj;
8412 	mmap_event->min = min;
8413 	mmap_event->ino = ino;
8414 	mmap_event->ino_generation = gen;
8415 	mmap_event->prot = prot;
8416 	mmap_event->flags = flags;
8417 
8418 	if (!(vma->vm_flags & VM_EXEC))
8419 		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8420 
8421 	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8422 
8423 	if (atomic_read(&nr_build_id_events))
8424 		build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8425 
8426 	perf_iterate_sb(perf_event_mmap_output,
8427 		       mmap_event,
8428 		       NULL);
8429 
8430 	kfree(buf);
8431 }
8432 
8433 /*
8434  * Check whether inode and address range match filter criteria.
8435  */
perf_addr_filter_match(struct perf_addr_filter * filter,struct file * file,unsigned long offset,unsigned long size)8436 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8437 				     struct file *file, unsigned long offset,
8438 				     unsigned long size)
8439 {
8440 	/* d_inode(NULL) won't be equal to any mapped user-space file */
8441 	if (!filter->path.dentry)
8442 		return false;
8443 
8444 	if (d_inode(filter->path.dentry) != file_inode(file))
8445 		return false;
8446 
8447 	if (filter->offset > offset + size)
8448 		return false;
8449 
8450 	if (filter->offset + filter->size < offset)
8451 		return false;
8452 
8453 	return true;
8454 }
8455 
perf_addr_filter_vma_adjust(struct perf_addr_filter * filter,struct vm_area_struct * vma,struct perf_addr_filter_range * fr)8456 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8457 					struct vm_area_struct *vma,
8458 					struct perf_addr_filter_range *fr)
8459 {
8460 	unsigned long vma_size = vma->vm_end - vma->vm_start;
8461 	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8462 	struct file *file = vma->vm_file;
8463 
8464 	if (!perf_addr_filter_match(filter, file, off, vma_size))
8465 		return false;
8466 
8467 	if (filter->offset < off) {
8468 		fr->start = vma->vm_start;
8469 		fr->size = min(vma_size, filter->size - (off - filter->offset));
8470 	} else {
8471 		fr->start = vma->vm_start + filter->offset - off;
8472 		fr->size = min(vma->vm_end - fr->start, filter->size);
8473 	}
8474 
8475 	return true;
8476 }
8477 
__perf_addr_filters_adjust(struct perf_event * event,void * data)8478 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8479 {
8480 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8481 	struct vm_area_struct *vma = data;
8482 	struct perf_addr_filter *filter;
8483 	unsigned int restart = 0, count = 0;
8484 	unsigned long flags;
8485 
8486 	if (!has_addr_filter(event))
8487 		return;
8488 
8489 	if (!vma->vm_file)
8490 		return;
8491 
8492 	raw_spin_lock_irqsave(&ifh->lock, flags);
8493 	list_for_each_entry(filter, &ifh->list, entry) {
8494 		if (perf_addr_filter_vma_adjust(filter, vma,
8495 						&event->addr_filter_ranges[count]))
8496 			restart++;
8497 
8498 		count++;
8499 	}
8500 
8501 	if (restart)
8502 		event->addr_filters_gen++;
8503 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
8504 
8505 	if (restart)
8506 		perf_event_stop(event, 1);
8507 }
8508 
8509 /*
8510  * Adjust all task's events' filters to the new vma
8511  */
perf_addr_filters_adjust(struct vm_area_struct * vma)8512 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8513 {
8514 	struct perf_event_context *ctx;
8515 	int ctxn;
8516 
8517 	/*
8518 	 * Data tracing isn't supported yet and as such there is no need
8519 	 * to keep track of anything that isn't related to executable code:
8520 	 */
8521 	if (!(vma->vm_flags & VM_EXEC))
8522 		return;
8523 
8524 	rcu_read_lock();
8525 	for_each_task_context_nr(ctxn) {
8526 		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8527 		if (!ctx)
8528 			continue;
8529 
8530 		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8531 	}
8532 	rcu_read_unlock();
8533 }
8534 
perf_event_mmap(struct vm_area_struct * vma)8535 void perf_event_mmap(struct vm_area_struct *vma)
8536 {
8537 	struct perf_mmap_event mmap_event;
8538 
8539 	if (!atomic_read(&nr_mmap_events))
8540 		return;
8541 
8542 	mmap_event = (struct perf_mmap_event){
8543 		.vma	= vma,
8544 		/* .file_name */
8545 		/* .file_size */
8546 		.event_id  = {
8547 			.header = {
8548 				.type = PERF_RECORD_MMAP,
8549 				.misc = PERF_RECORD_MISC_USER,
8550 				/* .size */
8551 			},
8552 			/* .pid */
8553 			/* .tid */
8554 			.start  = vma->vm_start,
8555 			.len    = vma->vm_end - vma->vm_start,
8556 			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
8557 		},
8558 		/* .maj (attr_mmap2 only) */
8559 		/* .min (attr_mmap2 only) */
8560 		/* .ino (attr_mmap2 only) */
8561 		/* .ino_generation (attr_mmap2 only) */
8562 		/* .prot (attr_mmap2 only) */
8563 		/* .flags (attr_mmap2 only) */
8564 	};
8565 
8566 	perf_addr_filters_adjust(vma);
8567 	perf_event_mmap_event(&mmap_event);
8568 }
8569 
perf_event_aux_event(struct perf_event * event,unsigned long head,unsigned long size,u64 flags)8570 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8571 			  unsigned long size, u64 flags)
8572 {
8573 	struct perf_output_handle handle;
8574 	struct perf_sample_data sample;
8575 	struct perf_aux_event {
8576 		struct perf_event_header	header;
8577 		u64				offset;
8578 		u64				size;
8579 		u64				flags;
8580 	} rec = {
8581 		.header = {
8582 			.type = PERF_RECORD_AUX,
8583 			.misc = 0,
8584 			.size = sizeof(rec),
8585 		},
8586 		.offset		= head,
8587 		.size		= size,
8588 		.flags		= flags,
8589 	};
8590 	int ret;
8591 
8592 	perf_event_header__init_id(&rec.header, &sample, event);
8593 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8594 
8595 	if (ret)
8596 		return;
8597 
8598 	perf_output_put(&handle, rec);
8599 	perf_event__output_id_sample(event, &handle, &sample);
8600 
8601 	perf_output_end(&handle);
8602 }
8603 
8604 /*
8605  * Lost/dropped samples logging
8606  */
perf_log_lost_samples(struct perf_event * event,u64 lost)8607 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8608 {
8609 	struct perf_output_handle handle;
8610 	struct perf_sample_data sample;
8611 	int ret;
8612 
8613 	struct {
8614 		struct perf_event_header	header;
8615 		u64				lost;
8616 	} lost_samples_event = {
8617 		.header = {
8618 			.type = PERF_RECORD_LOST_SAMPLES,
8619 			.misc = 0,
8620 			.size = sizeof(lost_samples_event),
8621 		},
8622 		.lost		= lost,
8623 	};
8624 
8625 	perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8626 
8627 	ret = perf_output_begin(&handle, &sample, event,
8628 				lost_samples_event.header.size);
8629 	if (ret)
8630 		return;
8631 
8632 	perf_output_put(&handle, lost_samples_event);
8633 	perf_event__output_id_sample(event, &handle, &sample);
8634 	perf_output_end(&handle);
8635 }
8636 
8637 /*
8638  * context_switch tracking
8639  */
8640 
8641 struct perf_switch_event {
8642 	struct task_struct	*task;
8643 	struct task_struct	*next_prev;
8644 
8645 	struct {
8646 		struct perf_event_header	header;
8647 		u32				next_prev_pid;
8648 		u32				next_prev_tid;
8649 	} event_id;
8650 };
8651 
perf_event_switch_match(struct perf_event * event)8652 static int perf_event_switch_match(struct perf_event *event)
8653 {
8654 	return event->attr.context_switch;
8655 }
8656 
perf_event_switch_output(struct perf_event * event,void * data)8657 static void perf_event_switch_output(struct perf_event *event, void *data)
8658 {
8659 	struct perf_switch_event *se = data;
8660 	struct perf_output_handle handle;
8661 	struct perf_sample_data sample;
8662 	int ret;
8663 
8664 	if (!perf_event_switch_match(event))
8665 		return;
8666 
8667 	/* Only CPU-wide events are allowed to see next/prev pid/tid */
8668 	if (event->ctx->task) {
8669 		se->event_id.header.type = PERF_RECORD_SWITCH;
8670 		se->event_id.header.size = sizeof(se->event_id.header);
8671 	} else {
8672 		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8673 		se->event_id.header.size = sizeof(se->event_id);
8674 		se->event_id.next_prev_pid =
8675 					perf_event_pid(event, se->next_prev);
8676 		se->event_id.next_prev_tid =
8677 					perf_event_tid(event, se->next_prev);
8678 	}
8679 
8680 	perf_event_header__init_id(&se->event_id.header, &sample, event);
8681 
8682 	ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8683 	if (ret)
8684 		return;
8685 
8686 	if (event->ctx->task)
8687 		perf_output_put(&handle, se->event_id.header);
8688 	else
8689 		perf_output_put(&handle, se->event_id);
8690 
8691 	perf_event__output_id_sample(event, &handle, &sample);
8692 
8693 	perf_output_end(&handle);
8694 }
8695 
perf_event_switch(struct task_struct * task,struct task_struct * next_prev,bool sched_in)8696 static void perf_event_switch(struct task_struct *task,
8697 			      struct task_struct *next_prev, bool sched_in)
8698 {
8699 	struct perf_switch_event switch_event;
8700 
8701 	/* N.B. caller checks nr_switch_events != 0 */
8702 
8703 	switch_event = (struct perf_switch_event){
8704 		.task		= task,
8705 		.next_prev	= next_prev,
8706 		.event_id	= {
8707 			.header = {
8708 				/* .type */
8709 				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8710 				/* .size */
8711 			},
8712 			/* .next_prev_pid */
8713 			/* .next_prev_tid */
8714 		},
8715 	};
8716 
8717 	if (!sched_in && task->on_rq) {
8718 		switch_event.event_id.header.misc |=
8719 				PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8720 	}
8721 
8722 	perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8723 }
8724 
8725 /*
8726  * IRQ throttle logging
8727  */
8728 
perf_log_throttle(struct perf_event * event,int enable)8729 static void perf_log_throttle(struct perf_event *event, int enable)
8730 {
8731 	struct perf_output_handle handle;
8732 	struct perf_sample_data sample;
8733 	int ret;
8734 
8735 	struct {
8736 		struct perf_event_header	header;
8737 		u64				time;
8738 		u64				id;
8739 		u64				stream_id;
8740 	} throttle_event = {
8741 		.header = {
8742 			.type = PERF_RECORD_THROTTLE,
8743 			.misc = 0,
8744 			.size = sizeof(throttle_event),
8745 		},
8746 		.time		= perf_event_clock(event),
8747 		.id		= primary_event_id(event),
8748 		.stream_id	= event->id,
8749 	};
8750 
8751 	if (enable)
8752 		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8753 
8754 	perf_event_header__init_id(&throttle_event.header, &sample, event);
8755 
8756 	ret = perf_output_begin(&handle, &sample, event,
8757 				throttle_event.header.size);
8758 	if (ret)
8759 		return;
8760 
8761 	perf_output_put(&handle, throttle_event);
8762 	perf_event__output_id_sample(event, &handle, &sample);
8763 	perf_output_end(&handle);
8764 }
8765 
8766 /*
8767  * ksymbol register/unregister tracking
8768  */
8769 
8770 struct perf_ksymbol_event {
8771 	const char	*name;
8772 	int		name_len;
8773 	struct {
8774 		struct perf_event_header        header;
8775 		u64				addr;
8776 		u32				len;
8777 		u16				ksym_type;
8778 		u16				flags;
8779 	} event_id;
8780 };
8781 
perf_event_ksymbol_match(struct perf_event * event)8782 static int perf_event_ksymbol_match(struct perf_event *event)
8783 {
8784 	return event->attr.ksymbol;
8785 }
8786 
perf_event_ksymbol_output(struct perf_event * event,void * data)8787 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8788 {
8789 	struct perf_ksymbol_event *ksymbol_event = data;
8790 	struct perf_output_handle handle;
8791 	struct perf_sample_data sample;
8792 	int ret;
8793 
8794 	if (!perf_event_ksymbol_match(event))
8795 		return;
8796 
8797 	perf_event_header__init_id(&ksymbol_event->event_id.header,
8798 				   &sample, event);
8799 	ret = perf_output_begin(&handle, &sample, event,
8800 				ksymbol_event->event_id.header.size);
8801 	if (ret)
8802 		return;
8803 
8804 	perf_output_put(&handle, ksymbol_event->event_id);
8805 	__output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8806 	perf_event__output_id_sample(event, &handle, &sample);
8807 
8808 	perf_output_end(&handle);
8809 }
8810 
perf_event_ksymbol(u16 ksym_type,u64 addr,u32 len,bool unregister,const char * sym)8811 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8812 			const char *sym)
8813 {
8814 	struct perf_ksymbol_event ksymbol_event;
8815 	char name[KSYM_NAME_LEN];
8816 	u16 flags = 0;
8817 	int name_len;
8818 
8819 	if (!atomic_read(&nr_ksymbol_events))
8820 		return;
8821 
8822 	if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8823 	    ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8824 		goto err;
8825 
8826 	strlcpy(name, sym, KSYM_NAME_LEN);
8827 	name_len = strlen(name) + 1;
8828 	while (!IS_ALIGNED(name_len, sizeof(u64)))
8829 		name[name_len++] = '\0';
8830 	BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8831 
8832 	if (unregister)
8833 		flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8834 
8835 	ksymbol_event = (struct perf_ksymbol_event){
8836 		.name = name,
8837 		.name_len = name_len,
8838 		.event_id = {
8839 			.header = {
8840 				.type = PERF_RECORD_KSYMBOL,
8841 				.size = sizeof(ksymbol_event.event_id) +
8842 					name_len,
8843 			},
8844 			.addr = addr,
8845 			.len = len,
8846 			.ksym_type = ksym_type,
8847 			.flags = flags,
8848 		},
8849 	};
8850 
8851 	perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8852 	return;
8853 err:
8854 	WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8855 }
8856 
8857 /*
8858  * bpf program load/unload tracking
8859  */
8860 
8861 struct perf_bpf_event {
8862 	struct bpf_prog	*prog;
8863 	struct {
8864 		struct perf_event_header        header;
8865 		u16				type;
8866 		u16				flags;
8867 		u32				id;
8868 		u8				tag[BPF_TAG_SIZE];
8869 	} event_id;
8870 };
8871 
perf_event_bpf_match(struct perf_event * event)8872 static int perf_event_bpf_match(struct perf_event *event)
8873 {
8874 	return event->attr.bpf_event;
8875 }
8876 
perf_event_bpf_output(struct perf_event * event,void * data)8877 static void perf_event_bpf_output(struct perf_event *event, void *data)
8878 {
8879 	struct perf_bpf_event *bpf_event = data;
8880 	struct perf_output_handle handle;
8881 	struct perf_sample_data sample;
8882 	int ret;
8883 
8884 	if (!perf_event_bpf_match(event))
8885 		return;
8886 
8887 	perf_event_header__init_id(&bpf_event->event_id.header,
8888 				   &sample, event);
8889 	ret = perf_output_begin(&handle, data, event,
8890 				bpf_event->event_id.header.size);
8891 	if (ret)
8892 		return;
8893 
8894 	perf_output_put(&handle, bpf_event->event_id);
8895 	perf_event__output_id_sample(event, &handle, &sample);
8896 
8897 	perf_output_end(&handle);
8898 }
8899 
perf_event_bpf_emit_ksymbols(struct bpf_prog * prog,enum perf_bpf_event_type type)8900 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8901 					 enum perf_bpf_event_type type)
8902 {
8903 	bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8904 	int i;
8905 
8906 	if (prog->aux->func_cnt == 0) {
8907 		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8908 				   (u64)(unsigned long)prog->bpf_func,
8909 				   prog->jited_len, unregister,
8910 				   prog->aux->ksym.name);
8911 	} else {
8912 		for (i = 0; i < prog->aux->func_cnt; i++) {
8913 			struct bpf_prog *subprog = prog->aux->func[i];
8914 
8915 			perf_event_ksymbol(
8916 				PERF_RECORD_KSYMBOL_TYPE_BPF,
8917 				(u64)(unsigned long)subprog->bpf_func,
8918 				subprog->jited_len, unregister,
8919 				prog->aux->ksym.name);
8920 		}
8921 	}
8922 }
8923 
perf_event_bpf_event(struct bpf_prog * prog,enum perf_bpf_event_type type,u16 flags)8924 void perf_event_bpf_event(struct bpf_prog *prog,
8925 			  enum perf_bpf_event_type type,
8926 			  u16 flags)
8927 {
8928 	struct perf_bpf_event bpf_event;
8929 
8930 	if (type <= PERF_BPF_EVENT_UNKNOWN ||
8931 	    type >= PERF_BPF_EVENT_MAX)
8932 		return;
8933 
8934 	switch (type) {
8935 	case PERF_BPF_EVENT_PROG_LOAD:
8936 	case PERF_BPF_EVENT_PROG_UNLOAD:
8937 		if (atomic_read(&nr_ksymbol_events))
8938 			perf_event_bpf_emit_ksymbols(prog, type);
8939 		break;
8940 	default:
8941 		break;
8942 	}
8943 
8944 	if (!atomic_read(&nr_bpf_events))
8945 		return;
8946 
8947 	bpf_event = (struct perf_bpf_event){
8948 		.prog = prog,
8949 		.event_id = {
8950 			.header = {
8951 				.type = PERF_RECORD_BPF_EVENT,
8952 				.size = sizeof(bpf_event.event_id),
8953 			},
8954 			.type = type,
8955 			.flags = flags,
8956 			.id = prog->aux->id,
8957 		},
8958 	};
8959 
8960 	BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8961 
8962 	memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8963 	perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8964 }
8965 
8966 struct perf_text_poke_event {
8967 	const void		*old_bytes;
8968 	const void		*new_bytes;
8969 	size_t			pad;
8970 	u16			old_len;
8971 	u16			new_len;
8972 
8973 	struct {
8974 		struct perf_event_header	header;
8975 
8976 		u64				addr;
8977 	} event_id;
8978 };
8979 
perf_event_text_poke_match(struct perf_event * event)8980 static int perf_event_text_poke_match(struct perf_event *event)
8981 {
8982 	return event->attr.text_poke;
8983 }
8984 
perf_event_text_poke_output(struct perf_event * event,void * data)8985 static void perf_event_text_poke_output(struct perf_event *event, void *data)
8986 {
8987 	struct perf_text_poke_event *text_poke_event = data;
8988 	struct perf_output_handle handle;
8989 	struct perf_sample_data sample;
8990 	u64 padding = 0;
8991 	int ret;
8992 
8993 	if (!perf_event_text_poke_match(event))
8994 		return;
8995 
8996 	perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8997 
8998 	ret = perf_output_begin(&handle, &sample, event,
8999 				text_poke_event->event_id.header.size);
9000 	if (ret)
9001 		return;
9002 
9003 	perf_output_put(&handle, text_poke_event->event_id);
9004 	perf_output_put(&handle, text_poke_event->old_len);
9005 	perf_output_put(&handle, text_poke_event->new_len);
9006 
9007 	__output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9008 	__output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9009 
9010 	if (text_poke_event->pad)
9011 		__output_copy(&handle, &padding, text_poke_event->pad);
9012 
9013 	perf_event__output_id_sample(event, &handle, &sample);
9014 
9015 	perf_output_end(&handle);
9016 }
9017 
perf_event_text_poke(const void * addr,const void * old_bytes,size_t old_len,const void * new_bytes,size_t new_len)9018 void perf_event_text_poke(const void *addr, const void *old_bytes,
9019 			  size_t old_len, const void *new_bytes, size_t new_len)
9020 {
9021 	struct perf_text_poke_event text_poke_event;
9022 	size_t tot, pad;
9023 
9024 	if (!atomic_read(&nr_text_poke_events))
9025 		return;
9026 
9027 	tot  = sizeof(text_poke_event.old_len) + old_len;
9028 	tot += sizeof(text_poke_event.new_len) + new_len;
9029 	pad  = ALIGN(tot, sizeof(u64)) - tot;
9030 
9031 	text_poke_event = (struct perf_text_poke_event){
9032 		.old_bytes    = old_bytes,
9033 		.new_bytes    = new_bytes,
9034 		.pad          = pad,
9035 		.old_len      = old_len,
9036 		.new_len      = new_len,
9037 		.event_id  = {
9038 			.header = {
9039 				.type = PERF_RECORD_TEXT_POKE,
9040 				.misc = PERF_RECORD_MISC_KERNEL,
9041 				.size = sizeof(text_poke_event.event_id) + tot + pad,
9042 			},
9043 			.addr = (unsigned long)addr,
9044 		},
9045 	};
9046 
9047 	perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9048 }
9049 
perf_event_itrace_started(struct perf_event * event)9050 void perf_event_itrace_started(struct perf_event *event)
9051 {
9052 	event->attach_state |= PERF_ATTACH_ITRACE;
9053 }
9054 
perf_log_itrace_start(struct perf_event * event)9055 static void perf_log_itrace_start(struct perf_event *event)
9056 {
9057 	struct perf_output_handle handle;
9058 	struct perf_sample_data sample;
9059 	struct perf_aux_event {
9060 		struct perf_event_header        header;
9061 		u32				pid;
9062 		u32				tid;
9063 	} rec;
9064 	int ret;
9065 
9066 	if (event->parent)
9067 		event = event->parent;
9068 
9069 	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9070 	    event->attach_state & PERF_ATTACH_ITRACE)
9071 		return;
9072 
9073 	rec.header.type	= PERF_RECORD_ITRACE_START;
9074 	rec.header.misc	= 0;
9075 	rec.header.size	= sizeof(rec);
9076 	rec.pid	= perf_event_pid(event, current);
9077 	rec.tid	= perf_event_tid(event, current);
9078 
9079 	perf_event_header__init_id(&rec.header, &sample, event);
9080 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9081 
9082 	if (ret)
9083 		return;
9084 
9085 	perf_output_put(&handle, rec);
9086 	perf_event__output_id_sample(event, &handle, &sample);
9087 
9088 	perf_output_end(&handle);
9089 }
9090 
perf_report_aux_output_id(struct perf_event * event,u64 hw_id)9091 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9092 {
9093 	struct perf_output_handle handle;
9094 	struct perf_sample_data sample;
9095 	struct perf_aux_event {
9096 		struct perf_event_header        header;
9097 		u64				hw_id;
9098 	} rec;
9099 	int ret;
9100 
9101 	if (event->parent)
9102 		event = event->parent;
9103 
9104 	rec.header.type	= PERF_RECORD_AUX_OUTPUT_HW_ID;
9105 	rec.header.misc	= 0;
9106 	rec.header.size	= sizeof(rec);
9107 	rec.hw_id	= hw_id;
9108 
9109 	perf_event_header__init_id(&rec.header, &sample, event);
9110 	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9111 
9112 	if (ret)
9113 		return;
9114 
9115 	perf_output_put(&handle, rec);
9116 	perf_event__output_id_sample(event, &handle, &sample);
9117 
9118 	perf_output_end(&handle);
9119 }
9120 
9121 static int
__perf_event_account_interrupt(struct perf_event * event,int throttle)9122 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9123 {
9124 	struct hw_perf_event *hwc = &event->hw;
9125 	int ret = 0;
9126 	u64 seq;
9127 
9128 	seq = __this_cpu_read(perf_throttled_seq);
9129 	if (seq != hwc->interrupts_seq) {
9130 		hwc->interrupts_seq = seq;
9131 		hwc->interrupts = 1;
9132 	} else {
9133 		hwc->interrupts++;
9134 		if (unlikely(throttle
9135 			     && hwc->interrupts >= max_samples_per_tick)) {
9136 			__this_cpu_inc(perf_throttled_count);
9137 			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9138 			hwc->interrupts = MAX_INTERRUPTS;
9139 			perf_log_throttle(event, 0);
9140 			ret = 1;
9141 		}
9142 	}
9143 
9144 	if (event->attr.freq) {
9145 		u64 now = perf_clock();
9146 		s64 delta = now - hwc->freq_time_stamp;
9147 
9148 		hwc->freq_time_stamp = now;
9149 
9150 		if (delta > 0 && delta < 2*TICK_NSEC)
9151 			perf_adjust_period(event, delta, hwc->last_period, true);
9152 	}
9153 
9154 	return ret;
9155 }
9156 
perf_event_account_interrupt(struct perf_event * event)9157 int perf_event_account_interrupt(struct perf_event *event)
9158 {
9159 	return __perf_event_account_interrupt(event, 1);
9160 }
9161 
9162 /*
9163  * Generic event overflow handling, sampling.
9164  */
9165 
__perf_event_overflow(struct perf_event * event,int throttle,struct perf_sample_data * data,struct pt_regs * regs)9166 static int __perf_event_overflow(struct perf_event *event,
9167 				   int throttle, struct perf_sample_data *data,
9168 				   struct pt_regs *regs)
9169 {
9170 	int events = atomic_read(&event->event_limit);
9171 	int ret = 0;
9172 
9173 	/*
9174 	 * Non-sampling counters might still use the PMI to fold short
9175 	 * hardware counters, ignore those.
9176 	 */
9177 	if (unlikely(!is_sampling_event(event)))
9178 		return 0;
9179 
9180 	ret = __perf_event_account_interrupt(event, throttle);
9181 
9182 	/*
9183 	 * XXX event_limit might not quite work as expected on inherited
9184 	 * events
9185 	 */
9186 
9187 	event->pending_kill = POLL_IN;
9188 	if (events && atomic_dec_and_test(&event->event_limit)) {
9189 		ret = 1;
9190 		event->pending_kill = POLL_HUP;
9191 		event->pending_addr = data->addr;
9192 
9193 		perf_event_disable_inatomic(event);
9194 	}
9195 
9196 	READ_ONCE(event->overflow_handler)(event, data, regs);
9197 
9198 	if (*perf_event_fasync(event) && event->pending_kill) {
9199 		event->pending_wakeup = 1;
9200 		irq_work_queue(&event->pending);
9201 	}
9202 
9203 	return ret;
9204 }
9205 
perf_event_overflow(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9206 int perf_event_overflow(struct perf_event *event,
9207 			  struct perf_sample_data *data,
9208 			  struct pt_regs *regs)
9209 {
9210 	return __perf_event_overflow(event, 1, data, regs);
9211 }
9212 
9213 /*
9214  * Generic software event infrastructure
9215  */
9216 
9217 struct swevent_htable {
9218 	struct swevent_hlist		*swevent_hlist;
9219 	struct mutex			hlist_mutex;
9220 	int				hlist_refcount;
9221 
9222 	/* Recursion avoidance in each contexts */
9223 	int				recursion[PERF_NR_CONTEXTS];
9224 };
9225 
9226 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9227 
9228 /*
9229  * We directly increment event->count and keep a second value in
9230  * event->hw.period_left to count intervals. This period event
9231  * is kept in the range [-sample_period, 0] so that we can use the
9232  * sign as trigger.
9233  */
9234 
perf_swevent_set_period(struct perf_event * event)9235 u64 perf_swevent_set_period(struct perf_event *event)
9236 {
9237 	struct hw_perf_event *hwc = &event->hw;
9238 	u64 period = hwc->last_period;
9239 	u64 nr, offset;
9240 	s64 old, val;
9241 
9242 	hwc->last_period = hwc->sample_period;
9243 
9244 again:
9245 	old = val = local64_read(&hwc->period_left);
9246 	if (val < 0)
9247 		return 0;
9248 
9249 	nr = div64_u64(period + val, period);
9250 	offset = nr * period;
9251 	val -= offset;
9252 	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9253 		goto again;
9254 
9255 	return nr;
9256 }
9257 
perf_swevent_overflow(struct perf_event * event,u64 overflow,struct perf_sample_data * data,struct pt_regs * regs)9258 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9259 				    struct perf_sample_data *data,
9260 				    struct pt_regs *regs)
9261 {
9262 	struct hw_perf_event *hwc = &event->hw;
9263 	int throttle = 0;
9264 
9265 	if (!overflow)
9266 		overflow = perf_swevent_set_period(event);
9267 
9268 	if (hwc->interrupts == MAX_INTERRUPTS)
9269 		return;
9270 
9271 	for (; overflow; overflow--) {
9272 		if (__perf_event_overflow(event, throttle,
9273 					    data, regs)) {
9274 			/*
9275 			 * We inhibit the overflow from happening when
9276 			 * hwc->interrupts == MAX_INTERRUPTS.
9277 			 */
9278 			break;
9279 		}
9280 		throttle = 1;
9281 	}
9282 }
9283 
perf_swevent_event(struct perf_event * event,u64 nr,struct perf_sample_data * data,struct pt_regs * regs)9284 static void perf_swevent_event(struct perf_event *event, u64 nr,
9285 			       struct perf_sample_data *data,
9286 			       struct pt_regs *regs)
9287 {
9288 	struct hw_perf_event *hwc = &event->hw;
9289 
9290 	local64_add(nr, &event->count);
9291 
9292 	if (!regs)
9293 		return;
9294 
9295 	if (!is_sampling_event(event))
9296 		return;
9297 
9298 	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9299 		data->period = nr;
9300 		return perf_swevent_overflow(event, 1, data, regs);
9301 	} else
9302 		data->period = event->hw.last_period;
9303 
9304 	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9305 		return perf_swevent_overflow(event, 1, data, regs);
9306 
9307 	if (local64_add_negative(nr, &hwc->period_left))
9308 		return;
9309 
9310 	perf_swevent_overflow(event, 0, data, regs);
9311 }
9312 
perf_exclude_event(struct perf_event * event,struct pt_regs * regs)9313 static int perf_exclude_event(struct perf_event *event,
9314 			      struct pt_regs *regs)
9315 {
9316 	if (event->hw.state & PERF_HES_STOPPED)
9317 		return 1;
9318 
9319 	if (regs) {
9320 		if (event->attr.exclude_user && user_mode(regs))
9321 			return 1;
9322 
9323 		if (event->attr.exclude_kernel && !user_mode(regs))
9324 			return 1;
9325 	}
9326 
9327 	return 0;
9328 }
9329 
perf_swevent_match(struct perf_event * event,enum perf_type_id type,u32 event_id,struct perf_sample_data * data,struct pt_regs * regs)9330 static int perf_swevent_match(struct perf_event *event,
9331 				enum perf_type_id type,
9332 				u32 event_id,
9333 				struct perf_sample_data *data,
9334 				struct pt_regs *regs)
9335 {
9336 	if (event->attr.type != type)
9337 		return 0;
9338 
9339 	if (event->attr.config != event_id)
9340 		return 0;
9341 
9342 	if (perf_exclude_event(event, regs))
9343 		return 0;
9344 
9345 	return 1;
9346 }
9347 
swevent_hash(u64 type,u32 event_id)9348 static inline u64 swevent_hash(u64 type, u32 event_id)
9349 {
9350 	u64 val = event_id | (type << 32);
9351 
9352 	return hash_64(val, SWEVENT_HLIST_BITS);
9353 }
9354 
9355 static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist * hlist,u64 type,u32 event_id)9356 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9357 {
9358 	u64 hash = swevent_hash(type, event_id);
9359 
9360 	return &hlist->heads[hash];
9361 }
9362 
9363 /* For the read side: events when they trigger */
9364 static inline struct hlist_head *
find_swevent_head_rcu(struct swevent_htable * swhash,u64 type,u32 event_id)9365 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9366 {
9367 	struct swevent_hlist *hlist;
9368 
9369 	hlist = rcu_dereference(swhash->swevent_hlist);
9370 	if (!hlist)
9371 		return NULL;
9372 
9373 	return __find_swevent_head(hlist, type, event_id);
9374 }
9375 
9376 /* For the event head insertion and removal in the hlist */
9377 static inline struct hlist_head *
find_swevent_head(struct swevent_htable * swhash,struct perf_event * event)9378 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9379 {
9380 	struct swevent_hlist *hlist;
9381 	u32 event_id = event->attr.config;
9382 	u64 type = event->attr.type;
9383 
9384 	/*
9385 	 * Event scheduling is always serialized against hlist allocation
9386 	 * and release. Which makes the protected version suitable here.
9387 	 * The context lock guarantees that.
9388 	 */
9389 	hlist = rcu_dereference_protected(swhash->swevent_hlist,
9390 					  lockdep_is_held(&event->ctx->lock));
9391 	if (!hlist)
9392 		return NULL;
9393 
9394 	return __find_swevent_head(hlist, type, event_id);
9395 }
9396 
do_perf_sw_event(enum perf_type_id type,u32 event_id,u64 nr,struct perf_sample_data * data,struct pt_regs * regs)9397 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9398 				    u64 nr,
9399 				    struct perf_sample_data *data,
9400 				    struct pt_regs *regs)
9401 {
9402 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9403 	struct perf_event *event;
9404 	struct hlist_head *head;
9405 
9406 	rcu_read_lock();
9407 	head = find_swevent_head_rcu(swhash, type, event_id);
9408 	if (!head)
9409 		goto end;
9410 
9411 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
9412 		if (perf_swevent_match(event, type, event_id, data, regs))
9413 			perf_swevent_event(event, nr, data, regs);
9414 	}
9415 end:
9416 	rcu_read_unlock();
9417 }
9418 
9419 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9420 
perf_swevent_get_recursion_context(void)9421 int perf_swevent_get_recursion_context(void)
9422 {
9423 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9424 
9425 	return get_recursion_context(swhash->recursion);
9426 }
9427 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9428 
perf_swevent_put_recursion_context(int rctx)9429 void perf_swevent_put_recursion_context(int rctx)
9430 {
9431 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9432 
9433 	put_recursion_context(swhash->recursion, rctx);
9434 }
9435 
___perf_sw_event(u32 event_id,u64 nr,struct pt_regs * regs,u64 addr)9436 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9437 {
9438 	struct perf_sample_data data;
9439 
9440 	if (WARN_ON_ONCE(!regs))
9441 		return;
9442 
9443 	perf_sample_data_init(&data, addr, 0);
9444 	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9445 }
9446 
__perf_sw_event(u32 event_id,u64 nr,struct pt_regs * regs,u64 addr)9447 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9448 {
9449 	int rctx;
9450 
9451 	preempt_disable_notrace();
9452 	rctx = perf_swevent_get_recursion_context();
9453 	if (unlikely(rctx < 0))
9454 		goto fail;
9455 
9456 	___perf_sw_event(event_id, nr, regs, addr);
9457 
9458 	perf_swevent_put_recursion_context(rctx);
9459 fail:
9460 	preempt_enable_notrace();
9461 }
9462 
perf_swevent_read(struct perf_event * event)9463 static void perf_swevent_read(struct perf_event *event)
9464 {
9465 }
9466 
perf_swevent_add(struct perf_event * event,int flags)9467 static int perf_swevent_add(struct perf_event *event, int flags)
9468 {
9469 	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9470 	struct hw_perf_event *hwc = &event->hw;
9471 	struct hlist_head *head;
9472 
9473 	if (is_sampling_event(event)) {
9474 		hwc->last_period = hwc->sample_period;
9475 		perf_swevent_set_period(event);
9476 	}
9477 
9478 	hwc->state = !(flags & PERF_EF_START);
9479 
9480 	head = find_swevent_head(swhash, event);
9481 	if (WARN_ON_ONCE(!head))
9482 		return -EINVAL;
9483 
9484 	hlist_add_head_rcu(&event->hlist_entry, head);
9485 	perf_event_update_userpage(event);
9486 
9487 	return 0;
9488 }
9489 
perf_swevent_del(struct perf_event * event,int flags)9490 static void perf_swevent_del(struct perf_event *event, int flags)
9491 {
9492 	hlist_del_rcu(&event->hlist_entry);
9493 }
9494 
perf_swevent_start(struct perf_event * event,int flags)9495 static void perf_swevent_start(struct perf_event *event, int flags)
9496 {
9497 	event->hw.state = 0;
9498 }
9499 
perf_swevent_stop(struct perf_event * event,int flags)9500 static void perf_swevent_stop(struct perf_event *event, int flags)
9501 {
9502 	event->hw.state = PERF_HES_STOPPED;
9503 }
9504 
9505 /* Deref the hlist from the update side */
9506 static inline struct swevent_hlist *
swevent_hlist_deref(struct swevent_htable * swhash)9507 swevent_hlist_deref(struct swevent_htable *swhash)
9508 {
9509 	return rcu_dereference_protected(swhash->swevent_hlist,
9510 					 lockdep_is_held(&swhash->hlist_mutex));
9511 }
9512 
swevent_hlist_release(struct swevent_htable * swhash)9513 static void swevent_hlist_release(struct swevent_htable *swhash)
9514 {
9515 	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9516 
9517 	if (!hlist)
9518 		return;
9519 
9520 	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9521 	kfree_rcu(hlist, rcu_head);
9522 }
9523 
swevent_hlist_put_cpu(int cpu)9524 static void swevent_hlist_put_cpu(int cpu)
9525 {
9526 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9527 
9528 	mutex_lock(&swhash->hlist_mutex);
9529 
9530 	if (!--swhash->hlist_refcount)
9531 		swevent_hlist_release(swhash);
9532 
9533 	mutex_unlock(&swhash->hlist_mutex);
9534 }
9535 
swevent_hlist_put(void)9536 static void swevent_hlist_put(void)
9537 {
9538 	int cpu;
9539 
9540 	for_each_possible_cpu(cpu)
9541 		swevent_hlist_put_cpu(cpu);
9542 }
9543 
swevent_hlist_get_cpu(int cpu)9544 static int swevent_hlist_get_cpu(int cpu)
9545 {
9546 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9547 	int err = 0;
9548 
9549 	mutex_lock(&swhash->hlist_mutex);
9550 	if (!swevent_hlist_deref(swhash) &&
9551 	    cpumask_test_cpu(cpu, perf_online_mask)) {
9552 		struct swevent_hlist *hlist;
9553 
9554 		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9555 		if (!hlist) {
9556 			err = -ENOMEM;
9557 			goto exit;
9558 		}
9559 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
9560 	}
9561 	swhash->hlist_refcount++;
9562 exit:
9563 	mutex_unlock(&swhash->hlist_mutex);
9564 
9565 	return err;
9566 }
9567 
swevent_hlist_get(void)9568 static int swevent_hlist_get(void)
9569 {
9570 	int err, cpu, failed_cpu;
9571 
9572 	mutex_lock(&pmus_lock);
9573 	for_each_possible_cpu(cpu) {
9574 		err = swevent_hlist_get_cpu(cpu);
9575 		if (err) {
9576 			failed_cpu = cpu;
9577 			goto fail;
9578 		}
9579 	}
9580 	mutex_unlock(&pmus_lock);
9581 	return 0;
9582 fail:
9583 	for_each_possible_cpu(cpu) {
9584 		if (cpu == failed_cpu)
9585 			break;
9586 		swevent_hlist_put_cpu(cpu);
9587 	}
9588 	mutex_unlock(&pmus_lock);
9589 	return err;
9590 }
9591 
9592 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9593 
sw_perf_event_destroy(struct perf_event * event)9594 static void sw_perf_event_destroy(struct perf_event *event)
9595 {
9596 	u64 event_id = event->attr.config;
9597 
9598 	WARN_ON(event->parent);
9599 
9600 	static_key_slow_dec(&perf_swevent_enabled[event_id]);
9601 	swevent_hlist_put();
9602 }
9603 
perf_swevent_init(struct perf_event * event)9604 static int perf_swevent_init(struct perf_event *event)
9605 {
9606 	u64 event_id = event->attr.config;
9607 
9608 	if (event->attr.type != PERF_TYPE_SOFTWARE)
9609 		return -ENOENT;
9610 
9611 	/*
9612 	 * no branch sampling for software events
9613 	 */
9614 	if (has_branch_stack(event))
9615 		return -EOPNOTSUPP;
9616 
9617 	switch (event_id) {
9618 	case PERF_COUNT_SW_CPU_CLOCK:
9619 	case PERF_COUNT_SW_TASK_CLOCK:
9620 		return -ENOENT;
9621 
9622 	default:
9623 		break;
9624 	}
9625 
9626 	if (event_id >= PERF_COUNT_SW_MAX)
9627 		return -ENOENT;
9628 
9629 	if (!event->parent) {
9630 		int err;
9631 
9632 		err = swevent_hlist_get();
9633 		if (err)
9634 			return err;
9635 
9636 		static_key_slow_inc(&perf_swevent_enabled[event_id]);
9637 		event->destroy = sw_perf_event_destroy;
9638 	}
9639 
9640 	return 0;
9641 }
9642 
9643 static struct pmu perf_swevent = {
9644 	.task_ctx_nr	= perf_sw_context,
9645 
9646 	.capabilities	= PERF_PMU_CAP_NO_NMI,
9647 
9648 	.event_init	= perf_swevent_init,
9649 	.add		= perf_swevent_add,
9650 	.del		= perf_swevent_del,
9651 	.start		= perf_swevent_start,
9652 	.stop		= perf_swevent_stop,
9653 	.read		= perf_swevent_read,
9654 };
9655 
9656 #ifdef CONFIG_EVENT_TRACING
9657 
perf_tp_filter_match(struct perf_event * event,struct perf_sample_data * data)9658 static int perf_tp_filter_match(struct perf_event *event,
9659 				struct perf_sample_data *data)
9660 {
9661 	void *record = data->raw->frag.data;
9662 
9663 	/* only top level events have filters set */
9664 	if (event->parent)
9665 		event = event->parent;
9666 
9667 	if (likely(!event->filter) || filter_match_preds(event->filter, record))
9668 		return 1;
9669 	return 0;
9670 }
9671 
perf_tp_event_match(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9672 static int perf_tp_event_match(struct perf_event *event,
9673 				struct perf_sample_data *data,
9674 				struct pt_regs *regs)
9675 {
9676 	if (event->hw.state & PERF_HES_STOPPED)
9677 		return 0;
9678 	/*
9679 	 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9680 	 */
9681 	if (event->attr.exclude_kernel && !user_mode(regs))
9682 		return 0;
9683 
9684 	if (!perf_tp_filter_match(event, data))
9685 		return 0;
9686 
9687 	return 1;
9688 }
9689 
perf_trace_run_bpf_submit(void * raw_data,int size,int rctx,struct trace_event_call * call,u64 count,struct pt_regs * regs,struct hlist_head * head,struct task_struct * task)9690 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9691 			       struct trace_event_call *call, u64 count,
9692 			       struct pt_regs *regs, struct hlist_head *head,
9693 			       struct task_struct *task)
9694 {
9695 	if (bpf_prog_array_valid(call)) {
9696 		*(struct pt_regs **)raw_data = regs;
9697 		if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9698 			perf_swevent_put_recursion_context(rctx);
9699 			return;
9700 		}
9701 	}
9702 	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9703 		      rctx, task);
9704 }
9705 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9706 
perf_tp_event(u16 event_type,u64 count,void * record,int entry_size,struct pt_regs * regs,struct hlist_head * head,int rctx,struct task_struct * task)9707 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9708 		   struct pt_regs *regs, struct hlist_head *head, int rctx,
9709 		   struct task_struct *task)
9710 {
9711 	struct perf_sample_data data;
9712 	struct perf_event *event;
9713 
9714 	struct perf_raw_record raw = {
9715 		.frag = {
9716 			.size = entry_size,
9717 			.data = record,
9718 		},
9719 	};
9720 
9721 	perf_sample_data_init(&data, 0, 0);
9722 	data.raw = &raw;
9723 
9724 	perf_trace_buf_update(record, event_type);
9725 
9726 	hlist_for_each_entry_rcu(event, head, hlist_entry) {
9727 		if (perf_tp_event_match(event, &data, regs))
9728 			perf_swevent_event(event, count, &data, regs);
9729 	}
9730 
9731 	/*
9732 	 * If we got specified a target task, also iterate its context and
9733 	 * deliver this event there too.
9734 	 */
9735 	if (task && task != current) {
9736 		struct perf_event_context *ctx;
9737 		struct trace_entry *entry = record;
9738 
9739 		rcu_read_lock();
9740 		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9741 		if (!ctx)
9742 			goto unlock;
9743 
9744 		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9745 			if (event->cpu != smp_processor_id())
9746 				continue;
9747 			if (event->attr.type != PERF_TYPE_TRACEPOINT)
9748 				continue;
9749 			if (event->attr.config != entry->type)
9750 				continue;
9751 			/* Cannot deliver synchronous signal to other task. */
9752 			if (event->attr.sigtrap)
9753 				continue;
9754 			if (perf_tp_event_match(event, &data, regs))
9755 				perf_swevent_event(event, count, &data, regs);
9756 		}
9757 unlock:
9758 		rcu_read_unlock();
9759 	}
9760 
9761 	perf_swevent_put_recursion_context(rctx);
9762 }
9763 EXPORT_SYMBOL_GPL(perf_tp_event);
9764 
tp_perf_event_destroy(struct perf_event * event)9765 static void tp_perf_event_destroy(struct perf_event *event)
9766 {
9767 	perf_trace_destroy(event);
9768 }
9769 
perf_tp_event_init(struct perf_event * event)9770 static int perf_tp_event_init(struct perf_event *event)
9771 {
9772 	int err;
9773 
9774 	if (event->attr.type != PERF_TYPE_TRACEPOINT)
9775 		return -ENOENT;
9776 
9777 	/*
9778 	 * no branch sampling for tracepoint events
9779 	 */
9780 	if (has_branch_stack(event))
9781 		return -EOPNOTSUPP;
9782 
9783 	err = perf_trace_init(event);
9784 	if (err)
9785 		return err;
9786 
9787 	event->destroy = tp_perf_event_destroy;
9788 
9789 	return 0;
9790 }
9791 
9792 static struct pmu perf_tracepoint = {
9793 	.task_ctx_nr	= perf_sw_context,
9794 
9795 	.event_init	= perf_tp_event_init,
9796 	.add		= perf_trace_add,
9797 	.del		= perf_trace_del,
9798 	.start		= perf_swevent_start,
9799 	.stop		= perf_swevent_stop,
9800 	.read		= perf_swevent_read,
9801 };
9802 
9803 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9804 /*
9805  * Flags in config, used by dynamic PMU kprobe and uprobe
9806  * The flags should match following PMU_FORMAT_ATTR().
9807  *
9808  * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9809  *                               if not set, create kprobe/uprobe
9810  *
9811  * The following values specify a reference counter (or semaphore in the
9812  * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9813  * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9814  *
9815  * PERF_UPROBE_REF_CTR_OFFSET_BITS	# of bits in config as th offset
9816  * PERF_UPROBE_REF_CTR_OFFSET_SHIFT	# of bits to shift left
9817  */
9818 enum perf_probe_config {
9819 	PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0,  /* [k,u]retprobe */
9820 	PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9821 	PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9822 };
9823 
9824 PMU_FORMAT_ATTR(retprobe, "config:0");
9825 #endif
9826 
9827 #ifdef CONFIG_KPROBE_EVENTS
9828 static struct attribute *kprobe_attrs[] = {
9829 	&format_attr_retprobe.attr,
9830 	NULL,
9831 };
9832 
9833 static struct attribute_group kprobe_format_group = {
9834 	.name = "format",
9835 	.attrs = kprobe_attrs,
9836 };
9837 
9838 static const struct attribute_group *kprobe_attr_groups[] = {
9839 	&kprobe_format_group,
9840 	NULL,
9841 };
9842 
9843 static int perf_kprobe_event_init(struct perf_event *event);
9844 static struct pmu perf_kprobe = {
9845 	.task_ctx_nr	= perf_sw_context,
9846 	.event_init	= perf_kprobe_event_init,
9847 	.add		= perf_trace_add,
9848 	.del		= perf_trace_del,
9849 	.start		= perf_swevent_start,
9850 	.stop		= perf_swevent_stop,
9851 	.read		= perf_swevent_read,
9852 	.attr_groups	= kprobe_attr_groups,
9853 };
9854 
perf_kprobe_event_init(struct perf_event * event)9855 static int perf_kprobe_event_init(struct perf_event *event)
9856 {
9857 	int err;
9858 	bool is_retprobe;
9859 
9860 	if (event->attr.type != perf_kprobe.type)
9861 		return -ENOENT;
9862 
9863 	if (!perfmon_capable())
9864 		return -EACCES;
9865 
9866 	/*
9867 	 * no branch sampling for probe events
9868 	 */
9869 	if (has_branch_stack(event))
9870 		return -EOPNOTSUPP;
9871 
9872 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9873 	err = perf_kprobe_init(event, is_retprobe);
9874 	if (err)
9875 		return err;
9876 
9877 	event->destroy = perf_kprobe_destroy;
9878 
9879 	return 0;
9880 }
9881 #endif /* CONFIG_KPROBE_EVENTS */
9882 
9883 #ifdef CONFIG_UPROBE_EVENTS
9884 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9885 
9886 static struct attribute *uprobe_attrs[] = {
9887 	&format_attr_retprobe.attr,
9888 	&format_attr_ref_ctr_offset.attr,
9889 	NULL,
9890 };
9891 
9892 static struct attribute_group uprobe_format_group = {
9893 	.name = "format",
9894 	.attrs = uprobe_attrs,
9895 };
9896 
9897 static const struct attribute_group *uprobe_attr_groups[] = {
9898 	&uprobe_format_group,
9899 	NULL,
9900 };
9901 
9902 static int perf_uprobe_event_init(struct perf_event *event);
9903 static struct pmu perf_uprobe = {
9904 	.task_ctx_nr	= perf_sw_context,
9905 	.event_init	= perf_uprobe_event_init,
9906 	.add		= perf_trace_add,
9907 	.del		= perf_trace_del,
9908 	.start		= perf_swevent_start,
9909 	.stop		= perf_swevent_stop,
9910 	.read		= perf_swevent_read,
9911 	.attr_groups	= uprobe_attr_groups,
9912 };
9913 
perf_uprobe_event_init(struct perf_event * event)9914 static int perf_uprobe_event_init(struct perf_event *event)
9915 {
9916 	int err;
9917 	unsigned long ref_ctr_offset;
9918 	bool is_retprobe;
9919 
9920 	if (event->attr.type != perf_uprobe.type)
9921 		return -ENOENT;
9922 
9923 	if (!perfmon_capable())
9924 		return -EACCES;
9925 
9926 	/*
9927 	 * no branch sampling for probe events
9928 	 */
9929 	if (has_branch_stack(event))
9930 		return -EOPNOTSUPP;
9931 
9932 	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9933 	ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9934 	err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9935 	if (err)
9936 		return err;
9937 
9938 	event->destroy = perf_uprobe_destroy;
9939 
9940 	return 0;
9941 }
9942 #endif /* CONFIG_UPROBE_EVENTS */
9943 
perf_tp_register(void)9944 static inline void perf_tp_register(void)
9945 {
9946 	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9947 #ifdef CONFIG_KPROBE_EVENTS
9948 	perf_pmu_register(&perf_kprobe, "kprobe", -1);
9949 #endif
9950 #ifdef CONFIG_UPROBE_EVENTS
9951 	perf_pmu_register(&perf_uprobe, "uprobe", -1);
9952 #endif
9953 }
9954 
perf_event_free_filter(struct perf_event * event)9955 static void perf_event_free_filter(struct perf_event *event)
9956 {
9957 	ftrace_profile_free_filter(event);
9958 }
9959 
9960 #ifdef CONFIG_BPF_SYSCALL
bpf_overflow_handler(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9961 static void bpf_overflow_handler(struct perf_event *event,
9962 				 struct perf_sample_data *data,
9963 				 struct pt_regs *regs)
9964 {
9965 	struct bpf_perf_event_data_kern ctx = {
9966 		.data = data,
9967 		.event = event,
9968 	};
9969 	struct bpf_prog *prog;
9970 	int ret = 0;
9971 
9972 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9973 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9974 		goto out;
9975 	rcu_read_lock();
9976 	prog = READ_ONCE(event->prog);
9977 	if (prog)
9978 		ret = bpf_prog_run(prog, &ctx);
9979 	rcu_read_unlock();
9980 out:
9981 	__this_cpu_dec(bpf_prog_active);
9982 	if (!ret)
9983 		return;
9984 
9985 	event->orig_overflow_handler(event, data, regs);
9986 }
9987 
perf_event_set_bpf_handler(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)9988 static int perf_event_set_bpf_handler(struct perf_event *event,
9989 				      struct bpf_prog *prog,
9990 				      u64 bpf_cookie)
9991 {
9992 	if (event->overflow_handler_context)
9993 		/* hw breakpoint or kernel counter */
9994 		return -EINVAL;
9995 
9996 	if (event->prog)
9997 		return -EEXIST;
9998 
9999 	if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10000 		return -EINVAL;
10001 
10002 	if (event->attr.precise_ip &&
10003 	    prog->call_get_stack &&
10004 	    (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10005 	     event->attr.exclude_callchain_kernel ||
10006 	     event->attr.exclude_callchain_user)) {
10007 		/*
10008 		 * On perf_event with precise_ip, calling bpf_get_stack()
10009 		 * may trigger unwinder warnings and occasional crashes.
10010 		 * bpf_get_[stack|stackid] works around this issue by using
10011 		 * callchain attached to perf_sample_data. If the
10012 		 * perf_event does not full (kernel and user) callchain
10013 		 * attached to perf_sample_data, do not allow attaching BPF
10014 		 * program that calls bpf_get_[stack|stackid].
10015 		 */
10016 		return -EPROTO;
10017 	}
10018 
10019 	event->prog = prog;
10020 	event->bpf_cookie = bpf_cookie;
10021 	event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10022 	WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10023 	return 0;
10024 }
10025 
perf_event_free_bpf_handler(struct perf_event * event)10026 static void perf_event_free_bpf_handler(struct perf_event *event)
10027 {
10028 	struct bpf_prog *prog = event->prog;
10029 
10030 	if (!prog)
10031 		return;
10032 
10033 	WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10034 	event->prog = NULL;
10035 	bpf_prog_put(prog);
10036 }
10037 #else
perf_event_set_bpf_handler(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)10038 static int perf_event_set_bpf_handler(struct perf_event *event,
10039 				      struct bpf_prog *prog,
10040 				      u64 bpf_cookie)
10041 {
10042 	return -EOPNOTSUPP;
10043 }
perf_event_free_bpf_handler(struct perf_event * event)10044 static void perf_event_free_bpf_handler(struct perf_event *event)
10045 {
10046 }
10047 #endif
10048 
10049 /*
10050  * returns true if the event is a tracepoint, or a kprobe/upprobe created
10051  * with perf_event_open()
10052  */
perf_event_is_tracing(struct perf_event * event)10053 static inline bool perf_event_is_tracing(struct perf_event *event)
10054 {
10055 	if (event->pmu == &perf_tracepoint)
10056 		return true;
10057 #ifdef CONFIG_KPROBE_EVENTS
10058 	if (event->pmu == &perf_kprobe)
10059 		return true;
10060 #endif
10061 #ifdef CONFIG_UPROBE_EVENTS
10062 	if (event->pmu == &perf_uprobe)
10063 		return true;
10064 #endif
10065 	return false;
10066 }
10067 
perf_event_set_bpf_prog(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)10068 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10069 			    u64 bpf_cookie)
10070 {
10071 	bool is_kprobe, is_tracepoint, is_syscall_tp;
10072 
10073 	if (!perf_event_is_tracing(event))
10074 		return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10075 
10076 	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10077 	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10078 	is_syscall_tp = is_syscall_trace_event(event->tp_event);
10079 	if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10080 		/* bpf programs can only be attached to u/kprobe or tracepoint */
10081 		return -EINVAL;
10082 
10083 	if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10084 	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10085 	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10086 		return -EINVAL;
10087 
10088 	/* Kprobe override only works for kprobes, not uprobes. */
10089 	if (prog->kprobe_override &&
10090 	    !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10091 		return -EINVAL;
10092 
10093 	if (is_tracepoint || is_syscall_tp) {
10094 		int off = trace_event_get_offsets(event->tp_event);
10095 
10096 		if (prog->aux->max_ctx_offset > off)
10097 			return -EACCES;
10098 	}
10099 
10100 	return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10101 }
10102 
perf_event_free_bpf_prog(struct perf_event * event)10103 void perf_event_free_bpf_prog(struct perf_event *event)
10104 {
10105 	if (!perf_event_is_tracing(event)) {
10106 		perf_event_free_bpf_handler(event);
10107 		return;
10108 	}
10109 	perf_event_detach_bpf_prog(event);
10110 }
10111 
10112 #else
10113 
perf_tp_register(void)10114 static inline void perf_tp_register(void)
10115 {
10116 }
10117 
perf_event_free_filter(struct perf_event * event)10118 static void perf_event_free_filter(struct perf_event *event)
10119 {
10120 }
10121 
perf_event_set_bpf_prog(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)10122 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10123 			    u64 bpf_cookie)
10124 {
10125 	return -ENOENT;
10126 }
10127 
perf_event_free_bpf_prog(struct perf_event * event)10128 void perf_event_free_bpf_prog(struct perf_event *event)
10129 {
10130 }
10131 #endif /* CONFIG_EVENT_TRACING */
10132 
10133 #ifdef CONFIG_HAVE_HW_BREAKPOINT
perf_bp_event(struct perf_event * bp,void * data)10134 void perf_bp_event(struct perf_event *bp, void *data)
10135 {
10136 	struct perf_sample_data sample;
10137 	struct pt_regs *regs = data;
10138 
10139 	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10140 
10141 	if (!bp->hw.state && !perf_exclude_event(bp, regs))
10142 		perf_swevent_event(bp, 1, &sample, regs);
10143 }
10144 #endif
10145 
10146 /*
10147  * Allocate a new address filter
10148  */
10149 static struct perf_addr_filter *
perf_addr_filter_new(struct perf_event * event,struct list_head * filters)10150 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10151 {
10152 	int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10153 	struct perf_addr_filter *filter;
10154 
10155 	filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10156 	if (!filter)
10157 		return NULL;
10158 
10159 	INIT_LIST_HEAD(&filter->entry);
10160 	list_add_tail(&filter->entry, filters);
10161 
10162 	return filter;
10163 }
10164 
free_filters_list(struct list_head * filters)10165 static void free_filters_list(struct list_head *filters)
10166 {
10167 	struct perf_addr_filter *filter, *iter;
10168 
10169 	list_for_each_entry_safe(filter, iter, filters, entry) {
10170 		path_put(&filter->path);
10171 		list_del(&filter->entry);
10172 		kfree(filter);
10173 	}
10174 }
10175 
10176 /*
10177  * Free existing address filters and optionally install new ones
10178  */
perf_addr_filters_splice(struct perf_event * event,struct list_head * head)10179 static void perf_addr_filters_splice(struct perf_event *event,
10180 				     struct list_head *head)
10181 {
10182 	unsigned long flags;
10183 	LIST_HEAD(list);
10184 
10185 	if (!has_addr_filter(event))
10186 		return;
10187 
10188 	/* don't bother with children, they don't have their own filters */
10189 	if (event->parent)
10190 		return;
10191 
10192 	raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10193 
10194 	list_splice_init(&event->addr_filters.list, &list);
10195 	if (head)
10196 		list_splice(head, &event->addr_filters.list);
10197 
10198 	raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10199 
10200 	free_filters_list(&list);
10201 }
10202 
10203 /*
10204  * Scan through mm's vmas and see if one of them matches the
10205  * @filter; if so, adjust filter's address range.
10206  * Called with mm::mmap_lock down for reading.
10207  */
perf_addr_filter_apply(struct perf_addr_filter * filter,struct mm_struct * mm,struct perf_addr_filter_range * fr)10208 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10209 				   struct mm_struct *mm,
10210 				   struct perf_addr_filter_range *fr)
10211 {
10212 	struct vm_area_struct *vma;
10213 
10214 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
10215 		if (!vma->vm_file)
10216 			continue;
10217 
10218 		if (perf_addr_filter_vma_adjust(filter, vma, fr))
10219 			return;
10220 	}
10221 }
10222 
10223 /*
10224  * Update event's address range filters based on the
10225  * task's existing mappings, if any.
10226  */
perf_event_addr_filters_apply(struct perf_event * event)10227 static void perf_event_addr_filters_apply(struct perf_event *event)
10228 {
10229 	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10230 	struct task_struct *task = READ_ONCE(event->ctx->task);
10231 	struct perf_addr_filter *filter;
10232 	struct mm_struct *mm = NULL;
10233 	unsigned int count = 0;
10234 	unsigned long flags;
10235 
10236 	/*
10237 	 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10238 	 * will stop on the parent's child_mutex that our caller is also holding
10239 	 */
10240 	if (task == TASK_TOMBSTONE)
10241 		return;
10242 
10243 	if (ifh->nr_file_filters) {
10244 		mm = get_task_mm(task);
10245 		if (!mm)
10246 			goto restart;
10247 
10248 		mmap_read_lock(mm);
10249 	}
10250 
10251 	raw_spin_lock_irqsave(&ifh->lock, flags);
10252 	list_for_each_entry(filter, &ifh->list, entry) {
10253 		if (filter->path.dentry) {
10254 			/*
10255 			 * Adjust base offset if the filter is associated to a
10256 			 * binary that needs to be mapped:
10257 			 */
10258 			event->addr_filter_ranges[count].start = 0;
10259 			event->addr_filter_ranges[count].size = 0;
10260 
10261 			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10262 		} else {
10263 			event->addr_filter_ranges[count].start = filter->offset;
10264 			event->addr_filter_ranges[count].size  = filter->size;
10265 		}
10266 
10267 		count++;
10268 	}
10269 
10270 	event->addr_filters_gen++;
10271 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
10272 
10273 	if (ifh->nr_file_filters) {
10274 		mmap_read_unlock(mm);
10275 
10276 		mmput(mm);
10277 	}
10278 
10279 restart:
10280 	perf_event_stop(event, 1);
10281 }
10282 
10283 /*
10284  * Address range filtering: limiting the data to certain
10285  * instruction address ranges. Filters are ioctl()ed to us from
10286  * userspace as ascii strings.
10287  *
10288  * Filter string format:
10289  *
10290  * ACTION RANGE_SPEC
10291  * where ACTION is one of the
10292  *  * "filter": limit the trace to this region
10293  *  * "start": start tracing from this address
10294  *  * "stop": stop tracing at this address/region;
10295  * RANGE_SPEC is
10296  *  * for kernel addresses: <start address>[/<size>]
10297  *  * for object files:     <start address>[/<size>]@</path/to/object/file>
10298  *
10299  * if <size> is not specified or is zero, the range is treated as a single
10300  * address; not valid for ACTION=="filter".
10301  */
10302 enum {
10303 	IF_ACT_NONE = -1,
10304 	IF_ACT_FILTER,
10305 	IF_ACT_START,
10306 	IF_ACT_STOP,
10307 	IF_SRC_FILE,
10308 	IF_SRC_KERNEL,
10309 	IF_SRC_FILEADDR,
10310 	IF_SRC_KERNELADDR,
10311 };
10312 
10313 enum {
10314 	IF_STATE_ACTION = 0,
10315 	IF_STATE_SOURCE,
10316 	IF_STATE_END,
10317 };
10318 
10319 static const match_table_t if_tokens = {
10320 	{ IF_ACT_FILTER,	"filter" },
10321 	{ IF_ACT_START,		"start" },
10322 	{ IF_ACT_STOP,		"stop" },
10323 	{ IF_SRC_FILE,		"%u/%u@%s" },
10324 	{ IF_SRC_KERNEL,	"%u/%u" },
10325 	{ IF_SRC_FILEADDR,	"%u@%s" },
10326 	{ IF_SRC_KERNELADDR,	"%u" },
10327 	{ IF_ACT_NONE,		NULL },
10328 };
10329 
10330 /*
10331  * Address filter string parser
10332  */
10333 static int
perf_event_parse_addr_filter(struct perf_event * event,char * fstr,struct list_head * filters)10334 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10335 			     struct list_head *filters)
10336 {
10337 	struct perf_addr_filter *filter = NULL;
10338 	char *start, *orig, *filename = NULL;
10339 	substring_t args[MAX_OPT_ARGS];
10340 	int state = IF_STATE_ACTION, token;
10341 	unsigned int kernel = 0;
10342 	int ret = -EINVAL;
10343 
10344 	orig = fstr = kstrdup(fstr, GFP_KERNEL);
10345 	if (!fstr)
10346 		return -ENOMEM;
10347 
10348 	while ((start = strsep(&fstr, " ,\n")) != NULL) {
10349 		static const enum perf_addr_filter_action_t actions[] = {
10350 			[IF_ACT_FILTER]	= PERF_ADDR_FILTER_ACTION_FILTER,
10351 			[IF_ACT_START]	= PERF_ADDR_FILTER_ACTION_START,
10352 			[IF_ACT_STOP]	= PERF_ADDR_FILTER_ACTION_STOP,
10353 		};
10354 		ret = -EINVAL;
10355 
10356 		if (!*start)
10357 			continue;
10358 
10359 		/* filter definition begins */
10360 		if (state == IF_STATE_ACTION) {
10361 			filter = perf_addr_filter_new(event, filters);
10362 			if (!filter)
10363 				goto fail;
10364 		}
10365 
10366 		token = match_token(start, if_tokens, args);
10367 		switch (token) {
10368 		case IF_ACT_FILTER:
10369 		case IF_ACT_START:
10370 		case IF_ACT_STOP:
10371 			if (state != IF_STATE_ACTION)
10372 				goto fail;
10373 
10374 			filter->action = actions[token];
10375 			state = IF_STATE_SOURCE;
10376 			break;
10377 
10378 		case IF_SRC_KERNELADDR:
10379 		case IF_SRC_KERNEL:
10380 			kernel = 1;
10381 			fallthrough;
10382 
10383 		case IF_SRC_FILEADDR:
10384 		case IF_SRC_FILE:
10385 			if (state != IF_STATE_SOURCE)
10386 				goto fail;
10387 
10388 			*args[0].to = 0;
10389 			ret = kstrtoul(args[0].from, 0, &filter->offset);
10390 			if (ret)
10391 				goto fail;
10392 
10393 			if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10394 				*args[1].to = 0;
10395 				ret = kstrtoul(args[1].from, 0, &filter->size);
10396 				if (ret)
10397 					goto fail;
10398 			}
10399 
10400 			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10401 				int fpos = token == IF_SRC_FILE ? 2 : 1;
10402 
10403 				kfree(filename);
10404 				filename = match_strdup(&args[fpos]);
10405 				if (!filename) {
10406 					ret = -ENOMEM;
10407 					goto fail;
10408 				}
10409 			}
10410 
10411 			state = IF_STATE_END;
10412 			break;
10413 
10414 		default:
10415 			goto fail;
10416 		}
10417 
10418 		/*
10419 		 * Filter definition is fully parsed, validate and install it.
10420 		 * Make sure that it doesn't contradict itself or the event's
10421 		 * attribute.
10422 		 */
10423 		if (state == IF_STATE_END) {
10424 			ret = -EINVAL;
10425 
10426 			/*
10427 			 * ACTION "filter" must have a non-zero length region
10428 			 * specified.
10429 			 */
10430 			if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10431 			    !filter->size)
10432 				goto fail;
10433 
10434 			if (!kernel) {
10435 				if (!filename)
10436 					goto fail;
10437 
10438 				/*
10439 				 * For now, we only support file-based filters
10440 				 * in per-task events; doing so for CPU-wide
10441 				 * events requires additional context switching
10442 				 * trickery, since same object code will be
10443 				 * mapped at different virtual addresses in
10444 				 * different processes.
10445 				 */
10446 				ret = -EOPNOTSUPP;
10447 				if (!event->ctx->task)
10448 					goto fail;
10449 
10450 				/* look up the path and grab its inode */
10451 				ret = kern_path(filename, LOOKUP_FOLLOW,
10452 						&filter->path);
10453 				if (ret)
10454 					goto fail;
10455 
10456 				ret = -EINVAL;
10457 				if (!filter->path.dentry ||
10458 				    !S_ISREG(d_inode(filter->path.dentry)
10459 					     ->i_mode))
10460 					goto fail;
10461 
10462 				event->addr_filters.nr_file_filters++;
10463 			}
10464 
10465 			/* ready to consume more filters */
10466 			kfree(filename);
10467 			filename = NULL;
10468 			state = IF_STATE_ACTION;
10469 			filter = NULL;
10470 			kernel = 0;
10471 		}
10472 	}
10473 
10474 	if (state != IF_STATE_ACTION)
10475 		goto fail;
10476 
10477 	kfree(filename);
10478 	kfree(orig);
10479 
10480 	return 0;
10481 
10482 fail:
10483 	kfree(filename);
10484 	free_filters_list(filters);
10485 	kfree(orig);
10486 
10487 	return ret;
10488 }
10489 
10490 static int
perf_event_set_addr_filter(struct perf_event * event,char * filter_str)10491 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10492 {
10493 	LIST_HEAD(filters);
10494 	int ret;
10495 
10496 	/*
10497 	 * Since this is called in perf_ioctl() path, we're already holding
10498 	 * ctx::mutex.
10499 	 */
10500 	lockdep_assert_held(&event->ctx->mutex);
10501 
10502 	if (WARN_ON_ONCE(event->parent))
10503 		return -EINVAL;
10504 
10505 	ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10506 	if (ret)
10507 		goto fail_clear_files;
10508 
10509 	ret = event->pmu->addr_filters_validate(&filters);
10510 	if (ret)
10511 		goto fail_free_filters;
10512 
10513 	/* remove existing filters, if any */
10514 	perf_addr_filters_splice(event, &filters);
10515 
10516 	/* install new filters */
10517 	perf_event_for_each_child(event, perf_event_addr_filters_apply);
10518 
10519 	return ret;
10520 
10521 fail_free_filters:
10522 	free_filters_list(&filters);
10523 
10524 fail_clear_files:
10525 	event->addr_filters.nr_file_filters = 0;
10526 
10527 	return ret;
10528 }
10529 
perf_event_set_filter(struct perf_event * event,void __user * arg)10530 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10531 {
10532 	int ret = -EINVAL;
10533 	char *filter_str;
10534 
10535 	filter_str = strndup_user(arg, PAGE_SIZE);
10536 	if (IS_ERR(filter_str))
10537 		return PTR_ERR(filter_str);
10538 
10539 #ifdef CONFIG_EVENT_TRACING
10540 	if (perf_event_is_tracing(event)) {
10541 		struct perf_event_context *ctx = event->ctx;
10542 
10543 		/*
10544 		 * Beware, here be dragons!!
10545 		 *
10546 		 * the tracepoint muck will deadlock against ctx->mutex, but
10547 		 * the tracepoint stuff does not actually need it. So
10548 		 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10549 		 * already have a reference on ctx.
10550 		 *
10551 		 * This can result in event getting moved to a different ctx,
10552 		 * but that does not affect the tracepoint state.
10553 		 */
10554 		mutex_unlock(&ctx->mutex);
10555 		ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10556 		mutex_lock(&ctx->mutex);
10557 	} else
10558 #endif
10559 	if (has_addr_filter(event))
10560 		ret = perf_event_set_addr_filter(event, filter_str);
10561 
10562 	kfree(filter_str);
10563 	return ret;
10564 }
10565 
10566 /*
10567  * hrtimer based swevent callback
10568  */
10569 
perf_swevent_hrtimer(struct hrtimer * hrtimer)10570 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10571 {
10572 	enum hrtimer_restart ret = HRTIMER_RESTART;
10573 	struct perf_sample_data data;
10574 	struct pt_regs *regs;
10575 	struct perf_event *event;
10576 	u64 period;
10577 
10578 	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10579 
10580 	if (event->state != PERF_EVENT_STATE_ACTIVE)
10581 		return HRTIMER_NORESTART;
10582 
10583 	event->pmu->read(event);
10584 
10585 	perf_sample_data_init(&data, 0, event->hw.last_period);
10586 	regs = get_irq_regs();
10587 
10588 	if (regs && !perf_exclude_event(event, regs)) {
10589 		if (!(event->attr.exclude_idle && is_idle_task(current)))
10590 			if (__perf_event_overflow(event, 1, &data, regs))
10591 				ret = HRTIMER_NORESTART;
10592 	}
10593 
10594 	period = max_t(u64, 10000, event->hw.sample_period);
10595 	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10596 
10597 	return ret;
10598 }
10599 
perf_swevent_start_hrtimer(struct perf_event * event)10600 static void perf_swevent_start_hrtimer(struct perf_event *event)
10601 {
10602 	struct hw_perf_event *hwc = &event->hw;
10603 	s64 period;
10604 
10605 	if (!is_sampling_event(event))
10606 		return;
10607 
10608 	period = local64_read(&hwc->period_left);
10609 	if (period) {
10610 		if (period < 0)
10611 			period = 10000;
10612 
10613 		local64_set(&hwc->period_left, 0);
10614 	} else {
10615 		period = max_t(u64, 10000, hwc->sample_period);
10616 	}
10617 	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10618 		      HRTIMER_MODE_REL_PINNED_HARD);
10619 }
10620 
perf_swevent_cancel_hrtimer(struct perf_event * event)10621 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10622 {
10623 	struct hw_perf_event *hwc = &event->hw;
10624 
10625 	if (is_sampling_event(event)) {
10626 		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10627 		local64_set(&hwc->period_left, ktime_to_ns(remaining));
10628 
10629 		hrtimer_cancel(&hwc->hrtimer);
10630 	}
10631 }
10632 
perf_swevent_init_hrtimer(struct perf_event * event)10633 static void perf_swevent_init_hrtimer(struct perf_event *event)
10634 {
10635 	struct hw_perf_event *hwc = &event->hw;
10636 
10637 	if (!is_sampling_event(event))
10638 		return;
10639 
10640 	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10641 	hwc->hrtimer.function = perf_swevent_hrtimer;
10642 
10643 	/*
10644 	 * Since hrtimers have a fixed rate, we can do a static freq->period
10645 	 * mapping and avoid the whole period adjust feedback stuff.
10646 	 */
10647 	if (event->attr.freq) {
10648 		long freq = event->attr.sample_freq;
10649 
10650 		event->attr.sample_period = NSEC_PER_SEC / freq;
10651 		hwc->sample_period = event->attr.sample_period;
10652 		local64_set(&hwc->period_left, hwc->sample_period);
10653 		hwc->last_period = hwc->sample_period;
10654 		event->attr.freq = 0;
10655 	}
10656 }
10657 
10658 /*
10659  * Software event: cpu wall time clock
10660  */
10661 
cpu_clock_event_update(struct perf_event * event)10662 static void cpu_clock_event_update(struct perf_event *event)
10663 {
10664 	s64 prev;
10665 	u64 now;
10666 
10667 	now = local_clock();
10668 	prev = local64_xchg(&event->hw.prev_count, now);
10669 	local64_add(now - prev, &event->count);
10670 }
10671 
cpu_clock_event_start(struct perf_event * event,int flags)10672 static void cpu_clock_event_start(struct perf_event *event, int flags)
10673 {
10674 	local64_set(&event->hw.prev_count, local_clock());
10675 	perf_swevent_start_hrtimer(event);
10676 }
10677 
cpu_clock_event_stop(struct perf_event * event,int flags)10678 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10679 {
10680 	perf_swevent_cancel_hrtimer(event);
10681 	cpu_clock_event_update(event);
10682 }
10683 
cpu_clock_event_add(struct perf_event * event,int flags)10684 static int cpu_clock_event_add(struct perf_event *event, int flags)
10685 {
10686 	if (flags & PERF_EF_START)
10687 		cpu_clock_event_start(event, flags);
10688 	perf_event_update_userpage(event);
10689 
10690 	return 0;
10691 }
10692 
cpu_clock_event_del(struct perf_event * event,int flags)10693 static void cpu_clock_event_del(struct perf_event *event, int flags)
10694 {
10695 	cpu_clock_event_stop(event, flags);
10696 }
10697 
cpu_clock_event_read(struct perf_event * event)10698 static void cpu_clock_event_read(struct perf_event *event)
10699 {
10700 	cpu_clock_event_update(event);
10701 }
10702 
cpu_clock_event_init(struct perf_event * event)10703 static int cpu_clock_event_init(struct perf_event *event)
10704 {
10705 	if (event->attr.type != PERF_TYPE_SOFTWARE)
10706 		return -ENOENT;
10707 
10708 	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10709 		return -ENOENT;
10710 
10711 	/*
10712 	 * no branch sampling for software events
10713 	 */
10714 	if (has_branch_stack(event))
10715 		return -EOPNOTSUPP;
10716 
10717 	perf_swevent_init_hrtimer(event);
10718 
10719 	return 0;
10720 }
10721 
10722 static struct pmu perf_cpu_clock = {
10723 	.task_ctx_nr	= perf_sw_context,
10724 
10725 	.capabilities	= PERF_PMU_CAP_NO_NMI,
10726 
10727 	.event_init	= cpu_clock_event_init,
10728 	.add		= cpu_clock_event_add,
10729 	.del		= cpu_clock_event_del,
10730 	.start		= cpu_clock_event_start,
10731 	.stop		= cpu_clock_event_stop,
10732 	.read		= cpu_clock_event_read,
10733 };
10734 
10735 /*
10736  * Software event: task time clock
10737  */
10738 
task_clock_event_update(struct perf_event * event,u64 now)10739 static void task_clock_event_update(struct perf_event *event, u64 now)
10740 {
10741 	u64 prev;
10742 	s64 delta;
10743 
10744 	prev = local64_xchg(&event->hw.prev_count, now);
10745 	delta = now - prev;
10746 	local64_add(delta, &event->count);
10747 }
10748 
task_clock_event_start(struct perf_event * event,int flags)10749 static void task_clock_event_start(struct perf_event *event, int flags)
10750 {
10751 	local64_set(&event->hw.prev_count, event->ctx->time);
10752 	perf_swevent_start_hrtimer(event);
10753 }
10754 
task_clock_event_stop(struct perf_event * event,int flags)10755 static void task_clock_event_stop(struct perf_event *event, int flags)
10756 {
10757 	perf_swevent_cancel_hrtimer(event);
10758 	task_clock_event_update(event, event->ctx->time);
10759 }
10760 
task_clock_event_add(struct perf_event * event,int flags)10761 static int task_clock_event_add(struct perf_event *event, int flags)
10762 {
10763 	if (flags & PERF_EF_START)
10764 		task_clock_event_start(event, flags);
10765 	perf_event_update_userpage(event);
10766 
10767 	return 0;
10768 }
10769 
task_clock_event_del(struct perf_event * event,int flags)10770 static void task_clock_event_del(struct perf_event *event, int flags)
10771 {
10772 	task_clock_event_stop(event, PERF_EF_UPDATE);
10773 }
10774 
task_clock_event_read(struct perf_event * event)10775 static void task_clock_event_read(struct perf_event *event)
10776 {
10777 	u64 now = perf_clock();
10778 	u64 delta = now - event->ctx->timestamp;
10779 	u64 time = event->ctx->time + delta;
10780 
10781 	task_clock_event_update(event, time);
10782 }
10783 
task_clock_event_init(struct perf_event * event)10784 static int task_clock_event_init(struct perf_event *event)
10785 {
10786 	if (event->attr.type != PERF_TYPE_SOFTWARE)
10787 		return -ENOENT;
10788 
10789 	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10790 		return -ENOENT;
10791 
10792 	/*
10793 	 * no branch sampling for software events
10794 	 */
10795 	if (has_branch_stack(event))
10796 		return -EOPNOTSUPP;
10797 
10798 	perf_swevent_init_hrtimer(event);
10799 
10800 	return 0;
10801 }
10802 
10803 static struct pmu perf_task_clock = {
10804 	.task_ctx_nr	= perf_sw_context,
10805 
10806 	.capabilities	= PERF_PMU_CAP_NO_NMI,
10807 
10808 	.event_init	= task_clock_event_init,
10809 	.add		= task_clock_event_add,
10810 	.del		= task_clock_event_del,
10811 	.start		= task_clock_event_start,
10812 	.stop		= task_clock_event_stop,
10813 	.read		= task_clock_event_read,
10814 };
10815 
perf_pmu_nop_void(struct pmu * pmu)10816 static void perf_pmu_nop_void(struct pmu *pmu)
10817 {
10818 }
10819 
perf_pmu_nop_txn(struct pmu * pmu,unsigned int flags)10820 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10821 {
10822 }
10823 
perf_pmu_nop_int(struct pmu * pmu)10824 static int perf_pmu_nop_int(struct pmu *pmu)
10825 {
10826 	return 0;
10827 }
10828 
perf_event_nop_int(struct perf_event * event,u64 value)10829 static int perf_event_nop_int(struct perf_event *event, u64 value)
10830 {
10831 	return 0;
10832 }
10833 
10834 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10835 
perf_pmu_start_txn(struct pmu * pmu,unsigned int flags)10836 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10837 {
10838 	__this_cpu_write(nop_txn_flags, flags);
10839 
10840 	if (flags & ~PERF_PMU_TXN_ADD)
10841 		return;
10842 
10843 	perf_pmu_disable(pmu);
10844 }
10845 
perf_pmu_commit_txn(struct pmu * pmu)10846 static int perf_pmu_commit_txn(struct pmu *pmu)
10847 {
10848 	unsigned int flags = __this_cpu_read(nop_txn_flags);
10849 
10850 	__this_cpu_write(nop_txn_flags, 0);
10851 
10852 	if (flags & ~PERF_PMU_TXN_ADD)
10853 		return 0;
10854 
10855 	perf_pmu_enable(pmu);
10856 	return 0;
10857 }
10858 
perf_pmu_cancel_txn(struct pmu * pmu)10859 static void perf_pmu_cancel_txn(struct pmu *pmu)
10860 {
10861 	unsigned int flags =  __this_cpu_read(nop_txn_flags);
10862 
10863 	__this_cpu_write(nop_txn_flags, 0);
10864 
10865 	if (flags & ~PERF_PMU_TXN_ADD)
10866 		return;
10867 
10868 	perf_pmu_enable(pmu);
10869 }
10870 
perf_event_idx_default(struct perf_event * event)10871 static int perf_event_idx_default(struct perf_event *event)
10872 {
10873 	return 0;
10874 }
10875 
10876 /*
10877  * Ensures all contexts with the same task_ctx_nr have the same
10878  * pmu_cpu_context too.
10879  */
find_pmu_context(int ctxn)10880 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10881 {
10882 	struct pmu *pmu;
10883 
10884 	if (ctxn < 0)
10885 		return NULL;
10886 
10887 	list_for_each_entry(pmu, &pmus, entry) {
10888 		if (pmu->task_ctx_nr == ctxn)
10889 			return pmu->pmu_cpu_context;
10890 	}
10891 
10892 	return NULL;
10893 }
10894 
free_pmu_context(struct pmu * pmu)10895 static void free_pmu_context(struct pmu *pmu)
10896 {
10897 	/*
10898 	 * Static contexts such as perf_sw_context have a global lifetime
10899 	 * and may be shared between different PMUs. Avoid freeing them
10900 	 * when a single PMU is going away.
10901 	 */
10902 	if (pmu->task_ctx_nr > perf_invalid_context)
10903 		return;
10904 
10905 	free_percpu(pmu->pmu_cpu_context);
10906 }
10907 
10908 /*
10909  * Let userspace know that this PMU supports address range filtering:
10910  */
nr_addr_filters_show(struct device * dev,struct device_attribute * attr,char * page)10911 static ssize_t nr_addr_filters_show(struct device *dev,
10912 				    struct device_attribute *attr,
10913 				    char *page)
10914 {
10915 	struct pmu *pmu = dev_get_drvdata(dev);
10916 
10917 	return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10918 }
10919 DEVICE_ATTR_RO(nr_addr_filters);
10920 
10921 static struct idr pmu_idr;
10922 
10923 static ssize_t
type_show(struct device * dev,struct device_attribute * attr,char * page)10924 type_show(struct device *dev, struct device_attribute *attr, char *page)
10925 {
10926 	struct pmu *pmu = dev_get_drvdata(dev);
10927 
10928 	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10929 }
10930 static DEVICE_ATTR_RO(type);
10931 
10932 static ssize_t
perf_event_mux_interval_ms_show(struct device * dev,struct device_attribute * attr,char * page)10933 perf_event_mux_interval_ms_show(struct device *dev,
10934 				struct device_attribute *attr,
10935 				char *page)
10936 {
10937 	struct pmu *pmu = dev_get_drvdata(dev);
10938 
10939 	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10940 }
10941 
10942 static DEFINE_MUTEX(mux_interval_mutex);
10943 
10944 static ssize_t
perf_event_mux_interval_ms_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)10945 perf_event_mux_interval_ms_store(struct device *dev,
10946 				 struct device_attribute *attr,
10947 				 const char *buf, size_t count)
10948 {
10949 	struct pmu *pmu = dev_get_drvdata(dev);
10950 	int timer, cpu, ret;
10951 
10952 	ret = kstrtoint(buf, 0, &timer);
10953 	if (ret)
10954 		return ret;
10955 
10956 	if (timer < 1)
10957 		return -EINVAL;
10958 
10959 	/* same value, noting to do */
10960 	if (timer == pmu->hrtimer_interval_ms)
10961 		return count;
10962 
10963 	mutex_lock(&mux_interval_mutex);
10964 	pmu->hrtimer_interval_ms = timer;
10965 
10966 	/* update all cpuctx for this PMU */
10967 	cpus_read_lock();
10968 	for_each_online_cpu(cpu) {
10969 		struct perf_cpu_context *cpuctx;
10970 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10971 		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10972 
10973 		cpu_function_call(cpu,
10974 			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10975 	}
10976 	cpus_read_unlock();
10977 	mutex_unlock(&mux_interval_mutex);
10978 
10979 	return count;
10980 }
10981 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10982 
10983 static struct attribute *pmu_dev_attrs[] = {
10984 	&dev_attr_type.attr,
10985 	&dev_attr_perf_event_mux_interval_ms.attr,
10986 	NULL,
10987 };
10988 ATTRIBUTE_GROUPS(pmu_dev);
10989 
10990 static int pmu_bus_running;
10991 static struct bus_type pmu_bus = {
10992 	.name		= "event_source",
10993 	.dev_groups	= pmu_dev_groups,
10994 };
10995 
pmu_dev_release(struct device * dev)10996 static void pmu_dev_release(struct device *dev)
10997 {
10998 	kfree(dev);
10999 }
11000 
pmu_dev_alloc(struct pmu * pmu)11001 static int pmu_dev_alloc(struct pmu *pmu)
11002 {
11003 	int ret = -ENOMEM;
11004 
11005 	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11006 	if (!pmu->dev)
11007 		goto out;
11008 
11009 	pmu->dev->groups = pmu->attr_groups;
11010 	device_initialize(pmu->dev);
11011 	ret = dev_set_name(pmu->dev, "%s", pmu->name);
11012 	if (ret)
11013 		goto free_dev;
11014 
11015 	dev_set_drvdata(pmu->dev, pmu);
11016 	pmu->dev->bus = &pmu_bus;
11017 	pmu->dev->release = pmu_dev_release;
11018 	ret = device_add(pmu->dev);
11019 	if (ret)
11020 		goto free_dev;
11021 
11022 	/* For PMUs with address filters, throw in an extra attribute: */
11023 	if (pmu->nr_addr_filters)
11024 		ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11025 
11026 	if (ret)
11027 		goto del_dev;
11028 
11029 	if (pmu->attr_update)
11030 		ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11031 
11032 	if (ret)
11033 		goto del_dev;
11034 
11035 out:
11036 	return ret;
11037 
11038 del_dev:
11039 	device_del(pmu->dev);
11040 
11041 free_dev:
11042 	put_device(pmu->dev);
11043 	goto out;
11044 }
11045 
11046 static struct lock_class_key cpuctx_mutex;
11047 static struct lock_class_key cpuctx_lock;
11048 
perf_pmu_register(struct pmu * pmu,const char * name,int type)11049 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11050 {
11051 	int cpu, ret, max = PERF_TYPE_MAX;
11052 
11053 	mutex_lock(&pmus_lock);
11054 	ret = -ENOMEM;
11055 	pmu->pmu_disable_count = alloc_percpu(int);
11056 	if (!pmu->pmu_disable_count)
11057 		goto unlock;
11058 
11059 	pmu->type = -1;
11060 	if (!name)
11061 		goto skip_type;
11062 	pmu->name = name;
11063 
11064 	if (type != PERF_TYPE_SOFTWARE) {
11065 		if (type >= 0)
11066 			max = type;
11067 
11068 		ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11069 		if (ret < 0)
11070 			goto free_pdc;
11071 
11072 		WARN_ON(type >= 0 && ret != type);
11073 
11074 		type = ret;
11075 	}
11076 	pmu->type = type;
11077 
11078 	if (pmu_bus_running) {
11079 		ret = pmu_dev_alloc(pmu);
11080 		if (ret)
11081 			goto free_idr;
11082 	}
11083 
11084 skip_type:
11085 	if (pmu->task_ctx_nr == perf_hw_context) {
11086 		static int hw_context_taken = 0;
11087 
11088 		/*
11089 		 * Other than systems with heterogeneous CPUs, it never makes
11090 		 * sense for two PMUs to share perf_hw_context. PMUs which are
11091 		 * uncore must use perf_invalid_context.
11092 		 */
11093 		if (WARN_ON_ONCE(hw_context_taken &&
11094 		    !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11095 			pmu->task_ctx_nr = perf_invalid_context;
11096 
11097 		hw_context_taken = 1;
11098 	}
11099 
11100 	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11101 	if (pmu->pmu_cpu_context)
11102 		goto got_cpu_context;
11103 
11104 	ret = -ENOMEM;
11105 	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11106 	if (!pmu->pmu_cpu_context)
11107 		goto free_dev;
11108 
11109 	for_each_possible_cpu(cpu) {
11110 		struct perf_cpu_context *cpuctx;
11111 
11112 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11113 		__perf_event_init_context(&cpuctx->ctx);
11114 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11115 		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11116 		cpuctx->ctx.pmu = pmu;
11117 		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11118 
11119 		__perf_mux_hrtimer_init(cpuctx, cpu);
11120 
11121 		cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11122 		cpuctx->heap = cpuctx->heap_default;
11123 	}
11124 
11125 got_cpu_context:
11126 	if (!pmu->start_txn) {
11127 		if (pmu->pmu_enable) {
11128 			/*
11129 			 * If we have pmu_enable/pmu_disable calls, install
11130 			 * transaction stubs that use that to try and batch
11131 			 * hardware accesses.
11132 			 */
11133 			pmu->start_txn  = perf_pmu_start_txn;
11134 			pmu->commit_txn = perf_pmu_commit_txn;
11135 			pmu->cancel_txn = perf_pmu_cancel_txn;
11136 		} else {
11137 			pmu->start_txn  = perf_pmu_nop_txn;
11138 			pmu->commit_txn = perf_pmu_nop_int;
11139 			pmu->cancel_txn = perf_pmu_nop_void;
11140 		}
11141 	}
11142 
11143 	if (!pmu->pmu_enable) {
11144 		pmu->pmu_enable  = perf_pmu_nop_void;
11145 		pmu->pmu_disable = perf_pmu_nop_void;
11146 	}
11147 
11148 	if (!pmu->check_period)
11149 		pmu->check_period = perf_event_nop_int;
11150 
11151 	if (!pmu->event_idx)
11152 		pmu->event_idx = perf_event_idx_default;
11153 
11154 	/*
11155 	 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11156 	 * since these cannot be in the IDR. This way the linear search
11157 	 * is fast, provided a valid software event is provided.
11158 	 */
11159 	if (type == PERF_TYPE_SOFTWARE || !name)
11160 		list_add_rcu(&pmu->entry, &pmus);
11161 	else
11162 		list_add_tail_rcu(&pmu->entry, &pmus);
11163 
11164 	atomic_set(&pmu->exclusive_cnt, 0);
11165 	ret = 0;
11166 unlock:
11167 	mutex_unlock(&pmus_lock);
11168 
11169 	return ret;
11170 
11171 free_dev:
11172 	device_del(pmu->dev);
11173 	put_device(pmu->dev);
11174 
11175 free_idr:
11176 	if (pmu->type != PERF_TYPE_SOFTWARE)
11177 		idr_remove(&pmu_idr, pmu->type);
11178 
11179 free_pdc:
11180 	free_percpu(pmu->pmu_disable_count);
11181 	goto unlock;
11182 }
11183 EXPORT_SYMBOL_GPL(perf_pmu_register);
11184 
perf_pmu_unregister(struct pmu * pmu)11185 void perf_pmu_unregister(struct pmu *pmu)
11186 {
11187 	mutex_lock(&pmus_lock);
11188 	list_del_rcu(&pmu->entry);
11189 
11190 	/*
11191 	 * We dereference the pmu list under both SRCU and regular RCU, so
11192 	 * synchronize against both of those.
11193 	 */
11194 	synchronize_srcu(&pmus_srcu);
11195 	synchronize_rcu();
11196 
11197 	free_percpu(pmu->pmu_disable_count);
11198 	if (pmu->type != PERF_TYPE_SOFTWARE)
11199 		idr_remove(&pmu_idr, pmu->type);
11200 	if (pmu_bus_running) {
11201 		if (pmu->nr_addr_filters)
11202 			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11203 		device_del(pmu->dev);
11204 		put_device(pmu->dev);
11205 	}
11206 	free_pmu_context(pmu);
11207 	mutex_unlock(&pmus_lock);
11208 }
11209 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11210 
has_extended_regs(struct perf_event * event)11211 static inline bool has_extended_regs(struct perf_event *event)
11212 {
11213 	return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11214 	       (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11215 }
11216 
perf_try_init_event(struct pmu * pmu,struct perf_event * event)11217 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11218 {
11219 	struct perf_event_context *ctx = NULL;
11220 	int ret;
11221 
11222 	if (!try_module_get(pmu->module))
11223 		return -ENODEV;
11224 
11225 	/*
11226 	 * A number of pmu->event_init() methods iterate the sibling_list to,
11227 	 * for example, validate if the group fits on the PMU. Therefore,
11228 	 * if this is a sibling event, acquire the ctx->mutex to protect
11229 	 * the sibling_list.
11230 	 */
11231 	if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11232 		/*
11233 		 * This ctx->mutex can nest when we're called through
11234 		 * inheritance. See the perf_event_ctx_lock_nested() comment.
11235 		 */
11236 		ctx = perf_event_ctx_lock_nested(event->group_leader,
11237 						 SINGLE_DEPTH_NESTING);
11238 		BUG_ON(!ctx);
11239 	}
11240 
11241 	event->pmu = pmu;
11242 	ret = pmu->event_init(event);
11243 
11244 	if (ctx)
11245 		perf_event_ctx_unlock(event->group_leader, ctx);
11246 
11247 	if (!ret) {
11248 		if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11249 		    has_extended_regs(event))
11250 			ret = -EOPNOTSUPP;
11251 
11252 		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11253 		    event_has_any_exclude_flag(event))
11254 			ret = -EINVAL;
11255 
11256 		if (ret && event->destroy)
11257 			event->destroy(event);
11258 	}
11259 
11260 	if (ret)
11261 		module_put(pmu->module);
11262 
11263 	return ret;
11264 }
11265 
perf_init_event(struct perf_event * event)11266 static struct pmu *perf_init_event(struct perf_event *event)
11267 {
11268 	bool extended_type = false;
11269 	int idx, type, ret;
11270 	struct pmu *pmu;
11271 
11272 	idx = srcu_read_lock(&pmus_srcu);
11273 
11274 	/* Try parent's PMU first: */
11275 	if (event->parent && event->parent->pmu) {
11276 		pmu = event->parent->pmu;
11277 		ret = perf_try_init_event(pmu, event);
11278 		if (!ret)
11279 			goto unlock;
11280 	}
11281 
11282 	/*
11283 	 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11284 	 * are often aliases for PERF_TYPE_RAW.
11285 	 */
11286 	type = event->attr.type;
11287 	if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11288 		type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11289 		if (!type) {
11290 			type = PERF_TYPE_RAW;
11291 		} else {
11292 			extended_type = true;
11293 			event->attr.config &= PERF_HW_EVENT_MASK;
11294 		}
11295 	}
11296 
11297 again:
11298 	rcu_read_lock();
11299 	pmu = idr_find(&pmu_idr, type);
11300 	rcu_read_unlock();
11301 	if (pmu) {
11302 		if (event->attr.type != type && type != PERF_TYPE_RAW &&
11303 		    !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11304 			goto fail;
11305 
11306 		ret = perf_try_init_event(pmu, event);
11307 		if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11308 			type = event->attr.type;
11309 			goto again;
11310 		}
11311 
11312 		if (ret)
11313 			pmu = ERR_PTR(ret);
11314 
11315 		goto unlock;
11316 	}
11317 
11318 	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11319 		ret = perf_try_init_event(pmu, event);
11320 		if (!ret)
11321 			goto unlock;
11322 
11323 		if (ret != -ENOENT) {
11324 			pmu = ERR_PTR(ret);
11325 			goto unlock;
11326 		}
11327 	}
11328 fail:
11329 	pmu = ERR_PTR(-ENOENT);
11330 unlock:
11331 	srcu_read_unlock(&pmus_srcu, idx);
11332 
11333 	return pmu;
11334 }
11335 
attach_sb_event(struct perf_event * event)11336 static void attach_sb_event(struct perf_event *event)
11337 {
11338 	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11339 
11340 	raw_spin_lock(&pel->lock);
11341 	list_add_rcu(&event->sb_list, &pel->list);
11342 	raw_spin_unlock(&pel->lock);
11343 }
11344 
11345 /*
11346  * We keep a list of all !task (and therefore per-cpu) events
11347  * that need to receive side-band records.
11348  *
11349  * This avoids having to scan all the various PMU per-cpu contexts
11350  * looking for them.
11351  */
account_pmu_sb_event(struct perf_event * event)11352 static void account_pmu_sb_event(struct perf_event *event)
11353 {
11354 	if (is_sb_event(event))
11355 		attach_sb_event(event);
11356 }
11357 
account_event_cpu(struct perf_event * event,int cpu)11358 static void account_event_cpu(struct perf_event *event, int cpu)
11359 {
11360 	if (event->parent)
11361 		return;
11362 
11363 	if (is_cgroup_event(event))
11364 		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11365 }
11366 
11367 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
account_freq_event_nohz(void)11368 static void account_freq_event_nohz(void)
11369 {
11370 #ifdef CONFIG_NO_HZ_FULL
11371 	/* Lock so we don't race with concurrent unaccount */
11372 	spin_lock(&nr_freq_lock);
11373 	if (atomic_inc_return(&nr_freq_events) == 1)
11374 		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11375 	spin_unlock(&nr_freq_lock);
11376 #endif
11377 }
11378 
account_freq_event(void)11379 static void account_freq_event(void)
11380 {
11381 	if (tick_nohz_full_enabled())
11382 		account_freq_event_nohz();
11383 	else
11384 		atomic_inc(&nr_freq_events);
11385 }
11386 
11387 
account_event(struct perf_event * event)11388 static void account_event(struct perf_event *event)
11389 {
11390 	bool inc = false;
11391 
11392 	if (event->parent)
11393 		return;
11394 
11395 	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11396 		inc = true;
11397 	if (event->attr.mmap || event->attr.mmap_data)
11398 		atomic_inc(&nr_mmap_events);
11399 	if (event->attr.build_id)
11400 		atomic_inc(&nr_build_id_events);
11401 	if (event->attr.comm)
11402 		atomic_inc(&nr_comm_events);
11403 	if (event->attr.namespaces)
11404 		atomic_inc(&nr_namespaces_events);
11405 	if (event->attr.cgroup)
11406 		atomic_inc(&nr_cgroup_events);
11407 	if (event->attr.task)
11408 		atomic_inc(&nr_task_events);
11409 	if (event->attr.freq)
11410 		account_freq_event();
11411 	if (event->attr.context_switch) {
11412 		atomic_inc(&nr_switch_events);
11413 		inc = true;
11414 	}
11415 	if (has_branch_stack(event))
11416 		inc = true;
11417 	if (is_cgroup_event(event))
11418 		inc = true;
11419 	if (event->attr.ksymbol)
11420 		atomic_inc(&nr_ksymbol_events);
11421 	if (event->attr.bpf_event)
11422 		atomic_inc(&nr_bpf_events);
11423 	if (event->attr.text_poke)
11424 		atomic_inc(&nr_text_poke_events);
11425 
11426 	if (inc) {
11427 		/*
11428 		 * We need the mutex here because static_branch_enable()
11429 		 * must complete *before* the perf_sched_count increment
11430 		 * becomes visible.
11431 		 */
11432 		if (atomic_inc_not_zero(&perf_sched_count))
11433 			goto enabled;
11434 
11435 		mutex_lock(&perf_sched_mutex);
11436 		if (!atomic_read(&perf_sched_count)) {
11437 			static_branch_enable(&perf_sched_events);
11438 			/*
11439 			 * Guarantee that all CPUs observe they key change and
11440 			 * call the perf scheduling hooks before proceeding to
11441 			 * install events that need them.
11442 			 */
11443 			synchronize_rcu();
11444 		}
11445 		/*
11446 		 * Now that we have waited for the sync_sched(), allow further
11447 		 * increments to by-pass the mutex.
11448 		 */
11449 		atomic_inc(&perf_sched_count);
11450 		mutex_unlock(&perf_sched_mutex);
11451 	}
11452 enabled:
11453 
11454 	account_event_cpu(event, event->cpu);
11455 
11456 	account_pmu_sb_event(event);
11457 }
11458 
11459 /*
11460  * Allocate and initialize an event structure
11461  */
11462 static struct perf_event *
perf_event_alloc(struct perf_event_attr * attr,int cpu,struct task_struct * task,struct perf_event * group_leader,struct perf_event * parent_event,perf_overflow_handler_t overflow_handler,void * context,int cgroup_fd)11463 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11464 		 struct task_struct *task,
11465 		 struct perf_event *group_leader,
11466 		 struct perf_event *parent_event,
11467 		 perf_overflow_handler_t overflow_handler,
11468 		 void *context, int cgroup_fd)
11469 {
11470 	struct pmu *pmu;
11471 	struct perf_event *event;
11472 	struct hw_perf_event *hwc;
11473 	long err = -EINVAL;
11474 	int node;
11475 
11476 	if ((unsigned)cpu >= nr_cpu_ids) {
11477 		if (!task || cpu != -1)
11478 			return ERR_PTR(-EINVAL);
11479 	}
11480 	if (attr->sigtrap && !task) {
11481 		/* Requires a task: avoid signalling random tasks. */
11482 		return ERR_PTR(-EINVAL);
11483 	}
11484 
11485 	node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11486 	event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11487 				      node);
11488 	if (!event)
11489 		return ERR_PTR(-ENOMEM);
11490 
11491 	/*
11492 	 * Single events are their own group leaders, with an
11493 	 * empty sibling list:
11494 	 */
11495 	if (!group_leader)
11496 		group_leader = event;
11497 
11498 	mutex_init(&event->child_mutex);
11499 	INIT_LIST_HEAD(&event->child_list);
11500 
11501 	INIT_LIST_HEAD(&event->event_entry);
11502 	INIT_LIST_HEAD(&event->sibling_list);
11503 	INIT_LIST_HEAD(&event->active_list);
11504 	init_event_group(event);
11505 	INIT_LIST_HEAD(&event->rb_entry);
11506 	INIT_LIST_HEAD(&event->active_entry);
11507 	INIT_LIST_HEAD(&event->addr_filters.list);
11508 	INIT_HLIST_NODE(&event->hlist_entry);
11509 
11510 
11511 	init_waitqueue_head(&event->waitq);
11512 	event->pending_disable = -1;
11513 	init_irq_work(&event->pending, perf_pending_event);
11514 
11515 	mutex_init(&event->mmap_mutex);
11516 	raw_spin_lock_init(&event->addr_filters.lock);
11517 
11518 	atomic_long_set(&event->refcount, 1);
11519 	event->cpu		= cpu;
11520 	event->attr		= *attr;
11521 	event->group_leader	= group_leader;
11522 	event->pmu		= NULL;
11523 	event->oncpu		= -1;
11524 
11525 	event->parent		= parent_event;
11526 
11527 	event->ns		= get_pid_ns(task_active_pid_ns(current));
11528 	event->id		= atomic64_inc_return(&perf_event_id);
11529 
11530 	event->state		= PERF_EVENT_STATE_INACTIVE;
11531 
11532 	if (parent_event)
11533 		event->event_caps = parent_event->event_caps;
11534 
11535 	if (event->attr.sigtrap)
11536 		atomic_set(&event->event_limit, 1);
11537 
11538 	if (task) {
11539 		event->attach_state = PERF_ATTACH_TASK;
11540 		/*
11541 		 * XXX pmu::event_init needs to know what task to account to
11542 		 * and we cannot use the ctx information because we need the
11543 		 * pmu before we get a ctx.
11544 		 */
11545 		event->hw.target = get_task_struct(task);
11546 	}
11547 
11548 	event->clock = &local_clock;
11549 	if (parent_event)
11550 		event->clock = parent_event->clock;
11551 
11552 	if (!overflow_handler && parent_event) {
11553 		overflow_handler = parent_event->overflow_handler;
11554 		context = parent_event->overflow_handler_context;
11555 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11556 		if (overflow_handler == bpf_overflow_handler) {
11557 			struct bpf_prog *prog = parent_event->prog;
11558 
11559 			bpf_prog_inc(prog);
11560 			event->prog = prog;
11561 			event->orig_overflow_handler =
11562 				parent_event->orig_overflow_handler;
11563 		}
11564 #endif
11565 	}
11566 
11567 	if (overflow_handler) {
11568 		event->overflow_handler	= overflow_handler;
11569 		event->overflow_handler_context = context;
11570 	} else if (is_write_backward(event)){
11571 		event->overflow_handler = perf_event_output_backward;
11572 		event->overflow_handler_context = NULL;
11573 	} else {
11574 		event->overflow_handler = perf_event_output_forward;
11575 		event->overflow_handler_context = NULL;
11576 	}
11577 
11578 	perf_event__state_init(event);
11579 
11580 	pmu = NULL;
11581 
11582 	hwc = &event->hw;
11583 	hwc->sample_period = attr->sample_period;
11584 	if (attr->freq && attr->sample_freq)
11585 		hwc->sample_period = 1;
11586 	hwc->last_period = hwc->sample_period;
11587 
11588 	local64_set(&hwc->period_left, hwc->sample_period);
11589 
11590 	/*
11591 	 * We currently do not support PERF_SAMPLE_READ on inherited events.
11592 	 * See perf_output_read().
11593 	 */
11594 	if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11595 		goto err_ns;
11596 
11597 	if (!has_branch_stack(event))
11598 		event->attr.branch_sample_type = 0;
11599 
11600 	pmu = perf_init_event(event);
11601 	if (IS_ERR(pmu)) {
11602 		err = PTR_ERR(pmu);
11603 		goto err_ns;
11604 	}
11605 
11606 	/*
11607 	 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11608 	 * be different on other CPUs in the uncore mask.
11609 	 */
11610 	if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11611 		err = -EINVAL;
11612 		goto err_pmu;
11613 	}
11614 
11615 	if (event->attr.aux_output &&
11616 	    !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11617 		err = -EOPNOTSUPP;
11618 		goto err_pmu;
11619 	}
11620 
11621 	if (cgroup_fd != -1) {
11622 		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11623 		if (err)
11624 			goto err_pmu;
11625 	}
11626 
11627 	err = exclusive_event_init(event);
11628 	if (err)
11629 		goto err_pmu;
11630 
11631 	if (has_addr_filter(event)) {
11632 		event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11633 						    sizeof(struct perf_addr_filter_range),
11634 						    GFP_KERNEL);
11635 		if (!event->addr_filter_ranges) {
11636 			err = -ENOMEM;
11637 			goto err_per_task;
11638 		}
11639 
11640 		/*
11641 		 * Clone the parent's vma offsets: they are valid until exec()
11642 		 * even if the mm is not shared with the parent.
11643 		 */
11644 		if (event->parent) {
11645 			struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11646 
11647 			raw_spin_lock_irq(&ifh->lock);
11648 			memcpy(event->addr_filter_ranges,
11649 			       event->parent->addr_filter_ranges,
11650 			       pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11651 			raw_spin_unlock_irq(&ifh->lock);
11652 		}
11653 
11654 		/* force hw sync on the address filters */
11655 		event->addr_filters_gen = 1;
11656 	}
11657 
11658 	if (!event->parent) {
11659 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11660 			err = get_callchain_buffers(attr->sample_max_stack);
11661 			if (err)
11662 				goto err_addr_filters;
11663 		}
11664 	}
11665 
11666 	err = security_perf_event_alloc(event);
11667 	if (err)
11668 		goto err_callchain_buffer;
11669 
11670 	/* symmetric to unaccount_event() in _free_event() */
11671 	account_event(event);
11672 
11673 	return event;
11674 
11675 err_callchain_buffer:
11676 	if (!event->parent) {
11677 		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11678 			put_callchain_buffers();
11679 	}
11680 err_addr_filters:
11681 	kfree(event->addr_filter_ranges);
11682 
11683 err_per_task:
11684 	exclusive_event_destroy(event);
11685 
11686 err_pmu:
11687 	if (is_cgroup_event(event))
11688 		perf_detach_cgroup(event);
11689 	if (event->destroy)
11690 		event->destroy(event);
11691 	module_put(pmu->module);
11692 err_ns:
11693 	if (event->ns)
11694 		put_pid_ns(event->ns);
11695 	if (event->hw.target)
11696 		put_task_struct(event->hw.target);
11697 	kmem_cache_free(perf_event_cache, event);
11698 
11699 	return ERR_PTR(err);
11700 }
11701 
perf_copy_attr(struct perf_event_attr __user * uattr,struct perf_event_attr * attr)11702 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11703 			  struct perf_event_attr *attr)
11704 {
11705 	u32 size;
11706 	int ret;
11707 
11708 	/* Zero the full structure, so that a short copy will be nice. */
11709 	memset(attr, 0, sizeof(*attr));
11710 
11711 	ret = get_user(size, &uattr->size);
11712 	if (ret)
11713 		return ret;
11714 
11715 	/* ABI compatibility quirk: */
11716 	if (!size)
11717 		size = PERF_ATTR_SIZE_VER0;
11718 	if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11719 		goto err_size;
11720 
11721 	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11722 	if (ret) {
11723 		if (ret == -E2BIG)
11724 			goto err_size;
11725 		return ret;
11726 	}
11727 
11728 	attr->size = size;
11729 
11730 	if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11731 		return -EINVAL;
11732 
11733 	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11734 		return -EINVAL;
11735 
11736 	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11737 		return -EINVAL;
11738 
11739 	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11740 		u64 mask = attr->branch_sample_type;
11741 
11742 		/* only using defined bits */
11743 		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11744 			return -EINVAL;
11745 
11746 		/* at least one branch bit must be set */
11747 		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11748 			return -EINVAL;
11749 
11750 		/* propagate priv level, when not set for branch */
11751 		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11752 
11753 			/* exclude_kernel checked on syscall entry */
11754 			if (!attr->exclude_kernel)
11755 				mask |= PERF_SAMPLE_BRANCH_KERNEL;
11756 
11757 			if (!attr->exclude_user)
11758 				mask |= PERF_SAMPLE_BRANCH_USER;
11759 
11760 			if (!attr->exclude_hv)
11761 				mask |= PERF_SAMPLE_BRANCH_HV;
11762 			/*
11763 			 * adjust user setting (for HW filter setup)
11764 			 */
11765 			attr->branch_sample_type = mask;
11766 		}
11767 		/* privileged levels capture (kernel, hv): check permissions */
11768 		if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11769 			ret = perf_allow_kernel(attr);
11770 			if (ret)
11771 				return ret;
11772 		}
11773 	}
11774 
11775 	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11776 		ret = perf_reg_validate(attr->sample_regs_user);
11777 		if (ret)
11778 			return ret;
11779 	}
11780 
11781 	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11782 		if (!arch_perf_have_user_stack_dump())
11783 			return -ENOSYS;
11784 
11785 		/*
11786 		 * We have __u32 type for the size, but so far
11787 		 * we can only use __u16 as maximum due to the
11788 		 * __u16 sample size limit.
11789 		 */
11790 		if (attr->sample_stack_user >= USHRT_MAX)
11791 			return -EINVAL;
11792 		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11793 			return -EINVAL;
11794 	}
11795 
11796 	if (!attr->sample_max_stack)
11797 		attr->sample_max_stack = sysctl_perf_event_max_stack;
11798 
11799 	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11800 		ret = perf_reg_validate(attr->sample_regs_intr);
11801 
11802 #ifndef CONFIG_CGROUP_PERF
11803 	if (attr->sample_type & PERF_SAMPLE_CGROUP)
11804 		return -EINVAL;
11805 #endif
11806 	if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11807 	    (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11808 		return -EINVAL;
11809 
11810 	if (!attr->inherit && attr->inherit_thread)
11811 		return -EINVAL;
11812 
11813 	if (attr->remove_on_exec && attr->enable_on_exec)
11814 		return -EINVAL;
11815 
11816 	if (attr->sigtrap && !attr->remove_on_exec)
11817 		return -EINVAL;
11818 
11819 out:
11820 	return ret;
11821 
11822 err_size:
11823 	put_user(sizeof(*attr), &uattr->size);
11824 	ret = -E2BIG;
11825 	goto out;
11826 }
11827 
mutex_lock_double(struct mutex * a,struct mutex * b)11828 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11829 {
11830 	if (b < a)
11831 		swap(a, b);
11832 
11833 	mutex_lock(a);
11834 	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11835 }
11836 
11837 static int
perf_event_set_output(struct perf_event * event,struct perf_event * output_event)11838 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11839 {
11840 	struct perf_buffer *rb = NULL;
11841 	int ret = -EINVAL;
11842 
11843 	if (!output_event) {
11844 		mutex_lock(&event->mmap_mutex);
11845 		goto set;
11846 	}
11847 
11848 	/* don't allow circular references */
11849 	if (event == output_event)
11850 		goto out;
11851 
11852 	/*
11853 	 * Don't allow cross-cpu buffers
11854 	 */
11855 	if (output_event->cpu != event->cpu)
11856 		goto out;
11857 
11858 	/*
11859 	 * If its not a per-cpu rb, it must be the same task.
11860 	 */
11861 	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11862 		goto out;
11863 
11864 	/*
11865 	 * Mixing clocks in the same buffer is trouble you don't need.
11866 	 */
11867 	if (output_event->clock != event->clock)
11868 		goto out;
11869 
11870 	/*
11871 	 * Either writing ring buffer from beginning or from end.
11872 	 * Mixing is not allowed.
11873 	 */
11874 	if (is_write_backward(output_event) != is_write_backward(event))
11875 		goto out;
11876 
11877 	/*
11878 	 * If both events generate aux data, they must be on the same PMU
11879 	 */
11880 	if (has_aux(event) && has_aux(output_event) &&
11881 	    event->pmu != output_event->pmu)
11882 		goto out;
11883 
11884 	/*
11885 	 * Hold both mmap_mutex to serialize against perf_mmap_close().  Since
11886 	 * output_event is already on rb->event_list, and the list iteration
11887 	 * restarts after every removal, it is guaranteed this new event is
11888 	 * observed *OR* if output_event is already removed, it's guaranteed we
11889 	 * observe !rb->mmap_count.
11890 	 */
11891 	mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
11892 set:
11893 	/* Can't redirect output if we've got an active mmap() */
11894 	if (atomic_read(&event->mmap_count))
11895 		goto unlock;
11896 
11897 	if (output_event) {
11898 		/* get the rb we want to redirect to */
11899 		rb = ring_buffer_get(output_event);
11900 		if (!rb)
11901 			goto unlock;
11902 
11903 		/* did we race against perf_mmap_close() */
11904 		if (!atomic_read(&rb->mmap_count)) {
11905 			ring_buffer_put(rb);
11906 			goto unlock;
11907 		}
11908 	}
11909 
11910 	ring_buffer_attach(event, rb);
11911 
11912 	ret = 0;
11913 unlock:
11914 	mutex_unlock(&event->mmap_mutex);
11915 	if (output_event)
11916 		mutex_unlock(&output_event->mmap_mutex);
11917 
11918 out:
11919 	return ret;
11920 }
11921 
perf_event_set_clock(struct perf_event * event,clockid_t clk_id)11922 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11923 {
11924 	bool nmi_safe = false;
11925 
11926 	switch (clk_id) {
11927 	case CLOCK_MONOTONIC:
11928 		event->clock = &ktime_get_mono_fast_ns;
11929 		nmi_safe = true;
11930 		break;
11931 
11932 	case CLOCK_MONOTONIC_RAW:
11933 		event->clock = &ktime_get_raw_fast_ns;
11934 		nmi_safe = true;
11935 		break;
11936 
11937 	case CLOCK_REALTIME:
11938 		event->clock = &ktime_get_real_ns;
11939 		break;
11940 
11941 	case CLOCK_BOOTTIME:
11942 		event->clock = &ktime_get_boottime_ns;
11943 		break;
11944 
11945 	case CLOCK_TAI:
11946 		event->clock = &ktime_get_clocktai_ns;
11947 		break;
11948 
11949 	default:
11950 		return -EINVAL;
11951 	}
11952 
11953 	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11954 		return -EINVAL;
11955 
11956 	return 0;
11957 }
11958 
11959 /*
11960  * Variation on perf_event_ctx_lock_nested(), except we take two context
11961  * mutexes.
11962  */
11963 static struct perf_event_context *
__perf_event_ctx_lock_double(struct perf_event * group_leader,struct perf_event_context * ctx)11964 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11965 			     struct perf_event_context *ctx)
11966 {
11967 	struct perf_event_context *gctx;
11968 
11969 again:
11970 	rcu_read_lock();
11971 	gctx = READ_ONCE(group_leader->ctx);
11972 	if (!refcount_inc_not_zero(&gctx->refcount)) {
11973 		rcu_read_unlock();
11974 		goto again;
11975 	}
11976 	rcu_read_unlock();
11977 
11978 	mutex_lock_double(&gctx->mutex, &ctx->mutex);
11979 
11980 	if (group_leader->ctx != gctx) {
11981 		mutex_unlock(&ctx->mutex);
11982 		mutex_unlock(&gctx->mutex);
11983 		put_ctx(gctx);
11984 		goto again;
11985 	}
11986 
11987 	return gctx;
11988 }
11989 
11990 static bool
perf_check_permission(struct perf_event_attr * attr,struct task_struct * task)11991 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
11992 {
11993 	unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
11994 	bool is_capable = perfmon_capable();
11995 
11996 	if (attr->sigtrap) {
11997 		/*
11998 		 * perf_event_attr::sigtrap sends signals to the other task.
11999 		 * Require the current task to also have CAP_KILL.
12000 		 */
12001 		rcu_read_lock();
12002 		is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12003 		rcu_read_unlock();
12004 
12005 		/*
12006 		 * If the required capabilities aren't available, checks for
12007 		 * ptrace permissions: upgrade to ATTACH, since sending signals
12008 		 * can effectively change the target task.
12009 		 */
12010 		ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12011 	}
12012 
12013 	/*
12014 	 * Preserve ptrace permission check for backwards compatibility. The
12015 	 * ptrace check also includes checks that the current task and other
12016 	 * task have matching uids, and is therefore not done here explicitly.
12017 	 */
12018 	return is_capable || ptrace_may_access(task, ptrace_mode);
12019 }
12020 
12021 /**
12022  * sys_perf_event_open - open a performance event, associate it to a task/cpu
12023  *
12024  * @attr_uptr:	event_id type attributes for monitoring/sampling
12025  * @pid:		target pid
12026  * @cpu:		target cpu
12027  * @group_fd:		group leader event fd
12028  * @flags:		perf event open flags
12029  */
SYSCALL_DEFINE5(perf_event_open,struct perf_event_attr __user *,attr_uptr,pid_t,pid,int,cpu,int,group_fd,unsigned long,flags)12030 SYSCALL_DEFINE5(perf_event_open,
12031 		struct perf_event_attr __user *, attr_uptr,
12032 		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12033 {
12034 	struct perf_event *group_leader = NULL, *output_event = NULL;
12035 	struct perf_event *event, *sibling;
12036 	struct perf_event_attr attr;
12037 	struct perf_event_context *ctx, *gctx;
12038 	struct file *event_file = NULL;
12039 	struct fd group = {NULL, 0};
12040 	struct task_struct *task = NULL;
12041 	struct pmu *pmu;
12042 	int event_fd;
12043 	int move_group = 0;
12044 	int err;
12045 	int f_flags = O_RDWR;
12046 	int cgroup_fd = -1;
12047 
12048 	/* for future expandability... */
12049 	if (flags & ~PERF_FLAG_ALL)
12050 		return -EINVAL;
12051 
12052 	/* Do we allow access to perf_event_open(2) ? */
12053 	err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12054 	if (err)
12055 		return err;
12056 
12057 	err = perf_copy_attr(attr_uptr, &attr);
12058 	if (err)
12059 		return err;
12060 
12061 	if (!attr.exclude_kernel) {
12062 		err = perf_allow_kernel(&attr);
12063 		if (err)
12064 			return err;
12065 	}
12066 
12067 	if (attr.namespaces) {
12068 		if (!perfmon_capable())
12069 			return -EACCES;
12070 	}
12071 
12072 	if (attr.freq) {
12073 		if (attr.sample_freq > sysctl_perf_event_sample_rate)
12074 			return -EINVAL;
12075 	} else {
12076 		if (attr.sample_period & (1ULL << 63))
12077 			return -EINVAL;
12078 	}
12079 
12080 	/* Only privileged users can get physical addresses */
12081 	if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12082 		err = perf_allow_kernel(&attr);
12083 		if (err)
12084 			return err;
12085 	}
12086 
12087 	/* REGS_INTR can leak data, lockdown must prevent this */
12088 	if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12089 		err = security_locked_down(LOCKDOWN_PERF);
12090 		if (err)
12091 			return err;
12092 	}
12093 
12094 	/*
12095 	 * In cgroup mode, the pid argument is used to pass the fd
12096 	 * opened to the cgroup directory in cgroupfs. The cpu argument
12097 	 * designates the cpu on which to monitor threads from that
12098 	 * cgroup.
12099 	 */
12100 	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12101 		return -EINVAL;
12102 
12103 	if (flags & PERF_FLAG_FD_CLOEXEC)
12104 		f_flags |= O_CLOEXEC;
12105 
12106 	event_fd = get_unused_fd_flags(f_flags);
12107 	if (event_fd < 0)
12108 		return event_fd;
12109 
12110 	if (group_fd != -1) {
12111 		err = perf_fget_light(group_fd, &group);
12112 		if (err)
12113 			goto err_fd;
12114 		group_leader = group.file->private_data;
12115 		if (flags & PERF_FLAG_FD_OUTPUT)
12116 			output_event = group_leader;
12117 		if (flags & PERF_FLAG_FD_NO_GROUP)
12118 			group_leader = NULL;
12119 	}
12120 
12121 	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12122 		task = find_lively_task_by_vpid(pid);
12123 		if (IS_ERR(task)) {
12124 			err = PTR_ERR(task);
12125 			goto err_group_fd;
12126 		}
12127 	}
12128 
12129 	if (task && group_leader &&
12130 	    group_leader->attr.inherit != attr.inherit) {
12131 		err = -EINVAL;
12132 		goto err_task;
12133 	}
12134 
12135 	if (flags & PERF_FLAG_PID_CGROUP)
12136 		cgroup_fd = pid;
12137 
12138 	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12139 				 NULL, NULL, cgroup_fd);
12140 	if (IS_ERR(event)) {
12141 		err = PTR_ERR(event);
12142 		goto err_task;
12143 	}
12144 
12145 	if (is_sampling_event(event)) {
12146 		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12147 			err = -EOPNOTSUPP;
12148 			goto err_alloc;
12149 		}
12150 	}
12151 
12152 	/*
12153 	 * Special case software events and allow them to be part of
12154 	 * any hardware group.
12155 	 */
12156 	pmu = event->pmu;
12157 
12158 	if (attr.use_clockid) {
12159 		err = perf_event_set_clock(event, attr.clockid);
12160 		if (err)
12161 			goto err_alloc;
12162 	}
12163 
12164 	if (pmu->task_ctx_nr == perf_sw_context)
12165 		event->event_caps |= PERF_EV_CAP_SOFTWARE;
12166 
12167 	if (group_leader) {
12168 		if (is_software_event(event) &&
12169 		    !in_software_context(group_leader)) {
12170 			/*
12171 			 * If the event is a sw event, but the group_leader
12172 			 * is on hw context.
12173 			 *
12174 			 * Allow the addition of software events to hw
12175 			 * groups, this is safe because software events
12176 			 * never fail to schedule.
12177 			 */
12178 			pmu = group_leader->ctx->pmu;
12179 		} else if (!is_software_event(event) &&
12180 			   is_software_event(group_leader) &&
12181 			   (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12182 			/*
12183 			 * In case the group is a pure software group, and we
12184 			 * try to add a hardware event, move the whole group to
12185 			 * the hardware context.
12186 			 */
12187 			move_group = 1;
12188 		}
12189 	}
12190 
12191 	/*
12192 	 * Get the target context (task or percpu):
12193 	 */
12194 	ctx = find_get_context(pmu, task, event);
12195 	if (IS_ERR(ctx)) {
12196 		err = PTR_ERR(ctx);
12197 		goto err_alloc;
12198 	}
12199 
12200 	/*
12201 	 * Look up the group leader (we will attach this event to it):
12202 	 */
12203 	if (group_leader) {
12204 		err = -EINVAL;
12205 
12206 		/*
12207 		 * Do not allow a recursive hierarchy (this new sibling
12208 		 * becoming part of another group-sibling):
12209 		 */
12210 		if (group_leader->group_leader != group_leader)
12211 			goto err_context;
12212 
12213 		/* All events in a group should have the same clock */
12214 		if (group_leader->clock != event->clock)
12215 			goto err_context;
12216 
12217 		/*
12218 		 * Make sure we're both events for the same CPU;
12219 		 * grouping events for different CPUs is broken; since
12220 		 * you can never concurrently schedule them anyhow.
12221 		 */
12222 		if (group_leader->cpu != event->cpu)
12223 			goto err_context;
12224 
12225 		/*
12226 		 * Make sure we're both on the same task, or both
12227 		 * per-CPU events.
12228 		 */
12229 		if (group_leader->ctx->task != ctx->task)
12230 			goto err_context;
12231 
12232 		/*
12233 		 * Do not allow to attach to a group in a different task
12234 		 * or CPU context. If we're moving SW events, we'll fix
12235 		 * this up later, so allow that.
12236 		 *
12237 		 * Racy, not holding group_leader->ctx->mutex, see comment with
12238 		 * perf_event_ctx_lock().
12239 		 */
12240 		if (!move_group && group_leader->ctx != ctx)
12241 			goto err_context;
12242 
12243 		/*
12244 		 * Only a group leader can be exclusive or pinned
12245 		 */
12246 		if (attr.exclusive || attr.pinned)
12247 			goto err_context;
12248 	}
12249 
12250 	if (output_event) {
12251 		err = perf_event_set_output(event, output_event);
12252 		if (err)
12253 			goto err_context;
12254 	}
12255 
12256 	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12257 					f_flags);
12258 	if (IS_ERR(event_file)) {
12259 		err = PTR_ERR(event_file);
12260 		event_file = NULL;
12261 		goto err_context;
12262 	}
12263 
12264 	if (task) {
12265 		err = down_read_interruptible(&task->signal->exec_update_lock);
12266 		if (err)
12267 			goto err_file;
12268 
12269 		/*
12270 		 * We must hold exec_update_lock across this and any potential
12271 		 * perf_install_in_context() call for this new event to
12272 		 * serialize against exec() altering our credentials (and the
12273 		 * perf_event_exit_task() that could imply).
12274 		 */
12275 		err = -EACCES;
12276 		if (!perf_check_permission(&attr, task))
12277 			goto err_cred;
12278 	}
12279 
12280 	if (move_group) {
12281 		gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12282 
12283 		if (gctx->task == TASK_TOMBSTONE) {
12284 			err = -ESRCH;
12285 			goto err_locked;
12286 		}
12287 
12288 		/*
12289 		 * Check if we raced against another sys_perf_event_open() call
12290 		 * moving the software group underneath us.
12291 		 */
12292 		if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12293 			/*
12294 			 * If someone moved the group out from under us, check
12295 			 * if this new event wound up on the same ctx, if so
12296 			 * its the regular !move_group case, otherwise fail.
12297 			 */
12298 			if (gctx != ctx) {
12299 				err = -EINVAL;
12300 				goto err_locked;
12301 			} else {
12302 				perf_event_ctx_unlock(group_leader, gctx);
12303 				move_group = 0;
12304 				goto not_move_group;
12305 			}
12306 		}
12307 
12308 		/*
12309 		 * Failure to create exclusive events returns -EBUSY.
12310 		 */
12311 		err = -EBUSY;
12312 		if (!exclusive_event_installable(group_leader, ctx))
12313 			goto err_locked;
12314 
12315 		for_each_sibling_event(sibling, group_leader) {
12316 			if (!exclusive_event_installable(sibling, ctx))
12317 				goto err_locked;
12318 		}
12319 	} else {
12320 		mutex_lock(&ctx->mutex);
12321 
12322 		/*
12323 		 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
12324 		 * see the group_leader && !move_group test earlier.
12325 		 */
12326 		if (group_leader && group_leader->ctx != ctx) {
12327 			err = -EINVAL;
12328 			goto err_locked;
12329 		}
12330 	}
12331 not_move_group:
12332 
12333 	if (ctx->task == TASK_TOMBSTONE) {
12334 		err = -ESRCH;
12335 		goto err_locked;
12336 	}
12337 
12338 	if (!perf_event_validate_size(event)) {
12339 		err = -E2BIG;
12340 		goto err_locked;
12341 	}
12342 
12343 	if (!task) {
12344 		/*
12345 		 * Check if the @cpu we're creating an event for is online.
12346 		 *
12347 		 * We use the perf_cpu_context::ctx::mutex to serialize against
12348 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12349 		 */
12350 		struct perf_cpu_context *cpuctx =
12351 			container_of(ctx, struct perf_cpu_context, ctx);
12352 
12353 		if (!cpuctx->online) {
12354 			err = -ENODEV;
12355 			goto err_locked;
12356 		}
12357 	}
12358 
12359 	if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12360 		err = -EINVAL;
12361 		goto err_locked;
12362 	}
12363 
12364 	/*
12365 	 * Must be under the same ctx::mutex as perf_install_in_context(),
12366 	 * because we need to serialize with concurrent event creation.
12367 	 */
12368 	if (!exclusive_event_installable(event, ctx)) {
12369 		err = -EBUSY;
12370 		goto err_locked;
12371 	}
12372 
12373 	WARN_ON_ONCE(ctx->parent_ctx);
12374 
12375 	/*
12376 	 * This is the point on no return; we cannot fail hereafter. This is
12377 	 * where we start modifying current state.
12378 	 */
12379 
12380 	if (move_group) {
12381 		/*
12382 		 * See perf_event_ctx_lock() for comments on the details
12383 		 * of swizzling perf_event::ctx.
12384 		 */
12385 		perf_remove_from_context(group_leader, 0);
12386 		put_ctx(gctx);
12387 
12388 		for_each_sibling_event(sibling, group_leader) {
12389 			perf_remove_from_context(sibling, 0);
12390 			put_ctx(gctx);
12391 		}
12392 
12393 		/*
12394 		 * Wait for everybody to stop referencing the events through
12395 		 * the old lists, before installing it on new lists.
12396 		 */
12397 		synchronize_rcu();
12398 
12399 		/*
12400 		 * Install the group siblings before the group leader.
12401 		 *
12402 		 * Because a group leader will try and install the entire group
12403 		 * (through the sibling list, which is still in-tact), we can
12404 		 * end up with siblings installed in the wrong context.
12405 		 *
12406 		 * By installing siblings first we NO-OP because they're not
12407 		 * reachable through the group lists.
12408 		 */
12409 		for_each_sibling_event(sibling, group_leader) {
12410 			perf_event__state_init(sibling);
12411 			perf_install_in_context(ctx, sibling, sibling->cpu);
12412 			get_ctx(ctx);
12413 		}
12414 
12415 		/*
12416 		 * Removing from the context ends up with disabled
12417 		 * event. What we want here is event in the initial
12418 		 * startup state, ready to be add into new context.
12419 		 */
12420 		perf_event__state_init(group_leader);
12421 		perf_install_in_context(ctx, group_leader, group_leader->cpu);
12422 		get_ctx(ctx);
12423 	}
12424 
12425 	/*
12426 	 * Precalculate sample_data sizes; do while holding ctx::mutex such
12427 	 * that we're serialized against further additions and before
12428 	 * perf_install_in_context() which is the point the event is active and
12429 	 * can use these values.
12430 	 */
12431 	perf_event__header_size(event);
12432 	perf_event__id_header_size(event);
12433 
12434 	event->owner = current;
12435 
12436 	perf_install_in_context(ctx, event, event->cpu);
12437 	perf_unpin_context(ctx);
12438 
12439 	if (move_group)
12440 		perf_event_ctx_unlock(group_leader, gctx);
12441 	mutex_unlock(&ctx->mutex);
12442 
12443 	if (task) {
12444 		up_read(&task->signal->exec_update_lock);
12445 		put_task_struct(task);
12446 	}
12447 
12448 	mutex_lock(&current->perf_event_mutex);
12449 	list_add_tail(&event->owner_entry, &current->perf_event_list);
12450 	mutex_unlock(&current->perf_event_mutex);
12451 
12452 	/*
12453 	 * Drop the reference on the group_event after placing the
12454 	 * new event on the sibling_list. This ensures destruction
12455 	 * of the group leader will find the pointer to itself in
12456 	 * perf_group_detach().
12457 	 */
12458 	fdput(group);
12459 	fd_install(event_fd, event_file);
12460 	return event_fd;
12461 
12462 err_locked:
12463 	if (move_group)
12464 		perf_event_ctx_unlock(group_leader, gctx);
12465 	mutex_unlock(&ctx->mutex);
12466 err_cred:
12467 	if (task)
12468 		up_read(&task->signal->exec_update_lock);
12469 err_file:
12470 	fput(event_file);
12471 err_context:
12472 	perf_unpin_context(ctx);
12473 	put_ctx(ctx);
12474 err_alloc:
12475 	/*
12476 	 * If event_file is set, the fput() above will have called ->release()
12477 	 * and that will take care of freeing the event.
12478 	 */
12479 	if (!event_file)
12480 		free_event(event);
12481 err_task:
12482 	if (task)
12483 		put_task_struct(task);
12484 err_group_fd:
12485 	fdput(group);
12486 err_fd:
12487 	put_unused_fd(event_fd);
12488 	return err;
12489 }
12490 
12491 /**
12492  * perf_event_create_kernel_counter
12493  *
12494  * @attr: attributes of the counter to create
12495  * @cpu: cpu in which the counter is bound
12496  * @task: task to profile (NULL for percpu)
12497  * @overflow_handler: callback to trigger when we hit the event
12498  * @context: context data could be used in overflow_handler callback
12499  */
12500 struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr * attr,int cpu,struct task_struct * task,perf_overflow_handler_t overflow_handler,void * context)12501 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12502 				 struct task_struct *task,
12503 				 perf_overflow_handler_t overflow_handler,
12504 				 void *context)
12505 {
12506 	struct perf_event_context *ctx;
12507 	struct perf_event *event;
12508 	int err;
12509 
12510 	/*
12511 	 * Grouping is not supported for kernel events, neither is 'AUX',
12512 	 * make sure the caller's intentions are adjusted.
12513 	 */
12514 	if (attr->aux_output)
12515 		return ERR_PTR(-EINVAL);
12516 
12517 	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12518 				 overflow_handler, context, -1);
12519 	if (IS_ERR(event)) {
12520 		err = PTR_ERR(event);
12521 		goto err;
12522 	}
12523 
12524 	/* Mark owner so we could distinguish it from user events. */
12525 	event->owner = TASK_TOMBSTONE;
12526 
12527 	/*
12528 	 * Get the target context (task or percpu):
12529 	 */
12530 	ctx = find_get_context(event->pmu, task, event);
12531 	if (IS_ERR(ctx)) {
12532 		err = PTR_ERR(ctx);
12533 		goto err_free;
12534 	}
12535 
12536 	WARN_ON_ONCE(ctx->parent_ctx);
12537 	mutex_lock(&ctx->mutex);
12538 	if (ctx->task == TASK_TOMBSTONE) {
12539 		err = -ESRCH;
12540 		goto err_unlock;
12541 	}
12542 
12543 	if (!task) {
12544 		/*
12545 		 * Check if the @cpu we're creating an event for is online.
12546 		 *
12547 		 * We use the perf_cpu_context::ctx::mutex to serialize against
12548 		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12549 		 */
12550 		struct perf_cpu_context *cpuctx =
12551 			container_of(ctx, struct perf_cpu_context, ctx);
12552 		if (!cpuctx->online) {
12553 			err = -ENODEV;
12554 			goto err_unlock;
12555 		}
12556 	}
12557 
12558 	if (!exclusive_event_installable(event, ctx)) {
12559 		err = -EBUSY;
12560 		goto err_unlock;
12561 	}
12562 
12563 	perf_install_in_context(ctx, event, event->cpu);
12564 	perf_unpin_context(ctx);
12565 	mutex_unlock(&ctx->mutex);
12566 
12567 	return event;
12568 
12569 err_unlock:
12570 	mutex_unlock(&ctx->mutex);
12571 	perf_unpin_context(ctx);
12572 	put_ctx(ctx);
12573 err_free:
12574 	free_event(event);
12575 err:
12576 	return ERR_PTR(err);
12577 }
12578 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12579 
perf_pmu_migrate_context(struct pmu * pmu,int src_cpu,int dst_cpu)12580 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12581 {
12582 	struct perf_event_context *src_ctx;
12583 	struct perf_event_context *dst_ctx;
12584 	struct perf_event *event, *tmp;
12585 	LIST_HEAD(events);
12586 
12587 	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12588 	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12589 
12590 	/*
12591 	 * See perf_event_ctx_lock() for comments on the details
12592 	 * of swizzling perf_event::ctx.
12593 	 */
12594 	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12595 	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12596 				 event_entry) {
12597 		perf_remove_from_context(event, 0);
12598 		unaccount_event_cpu(event, src_cpu);
12599 		put_ctx(src_ctx);
12600 		list_add(&event->migrate_entry, &events);
12601 	}
12602 
12603 	/*
12604 	 * Wait for the events to quiesce before re-instating them.
12605 	 */
12606 	synchronize_rcu();
12607 
12608 	/*
12609 	 * Re-instate events in 2 passes.
12610 	 *
12611 	 * Skip over group leaders and only install siblings on this first
12612 	 * pass, siblings will not get enabled without a leader, however a
12613 	 * leader will enable its siblings, even if those are still on the old
12614 	 * context.
12615 	 */
12616 	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12617 		if (event->group_leader == event)
12618 			continue;
12619 
12620 		list_del(&event->migrate_entry);
12621 		if (event->state >= PERF_EVENT_STATE_OFF)
12622 			event->state = PERF_EVENT_STATE_INACTIVE;
12623 		account_event_cpu(event, dst_cpu);
12624 		perf_install_in_context(dst_ctx, event, dst_cpu);
12625 		get_ctx(dst_ctx);
12626 	}
12627 
12628 	/*
12629 	 * Once all the siblings are setup properly, install the group leaders
12630 	 * to make it go.
12631 	 */
12632 	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12633 		list_del(&event->migrate_entry);
12634 		if (event->state >= PERF_EVENT_STATE_OFF)
12635 			event->state = PERF_EVENT_STATE_INACTIVE;
12636 		account_event_cpu(event, dst_cpu);
12637 		perf_install_in_context(dst_ctx, event, dst_cpu);
12638 		get_ctx(dst_ctx);
12639 	}
12640 	mutex_unlock(&dst_ctx->mutex);
12641 	mutex_unlock(&src_ctx->mutex);
12642 }
12643 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12644 
sync_child_event(struct perf_event * child_event)12645 static void sync_child_event(struct perf_event *child_event)
12646 {
12647 	struct perf_event *parent_event = child_event->parent;
12648 	u64 child_val;
12649 
12650 	if (child_event->attr.inherit_stat) {
12651 		struct task_struct *task = child_event->ctx->task;
12652 
12653 		if (task && task != TASK_TOMBSTONE)
12654 			perf_event_read_event(child_event, task);
12655 	}
12656 
12657 	child_val = perf_event_count(child_event);
12658 
12659 	/*
12660 	 * Add back the child's count to the parent's count:
12661 	 */
12662 	atomic64_add(child_val, &parent_event->child_count);
12663 	atomic64_add(child_event->total_time_enabled,
12664 		     &parent_event->child_total_time_enabled);
12665 	atomic64_add(child_event->total_time_running,
12666 		     &parent_event->child_total_time_running);
12667 }
12668 
12669 static void
perf_event_exit_event(struct perf_event * event,struct perf_event_context * ctx)12670 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12671 {
12672 	struct perf_event *parent_event = event->parent;
12673 	unsigned long detach_flags = 0;
12674 
12675 	if (parent_event) {
12676 		/*
12677 		 * Do not destroy the 'original' grouping; because of the
12678 		 * context switch optimization the original events could've
12679 		 * ended up in a random child task.
12680 		 *
12681 		 * If we were to destroy the original group, all group related
12682 		 * operations would cease to function properly after this
12683 		 * random child dies.
12684 		 *
12685 		 * Do destroy all inherited groups, we don't care about those
12686 		 * and being thorough is better.
12687 		 */
12688 		detach_flags = DETACH_GROUP | DETACH_CHILD;
12689 		mutex_lock(&parent_event->child_mutex);
12690 	}
12691 
12692 	perf_remove_from_context(event, detach_flags);
12693 
12694 	raw_spin_lock_irq(&ctx->lock);
12695 	if (event->state > PERF_EVENT_STATE_EXIT)
12696 		perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12697 	raw_spin_unlock_irq(&ctx->lock);
12698 
12699 	/*
12700 	 * Child events can be freed.
12701 	 */
12702 	if (parent_event) {
12703 		mutex_unlock(&parent_event->child_mutex);
12704 		/*
12705 		 * Kick perf_poll() for is_event_hup();
12706 		 */
12707 		perf_event_wakeup(parent_event);
12708 		free_event(event);
12709 		put_event(parent_event);
12710 		return;
12711 	}
12712 
12713 	/*
12714 	 * Parent events are governed by their filedesc, retain them.
12715 	 */
12716 	perf_event_wakeup(event);
12717 }
12718 
perf_event_exit_task_context(struct task_struct * child,int ctxn)12719 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12720 {
12721 	struct perf_event_context *child_ctx, *clone_ctx = NULL;
12722 	struct perf_event *child_event, *next;
12723 
12724 	WARN_ON_ONCE(child != current);
12725 
12726 	child_ctx = perf_pin_task_context(child, ctxn);
12727 	if (!child_ctx)
12728 		return;
12729 
12730 	/*
12731 	 * In order to reduce the amount of tricky in ctx tear-down, we hold
12732 	 * ctx::mutex over the entire thing. This serializes against almost
12733 	 * everything that wants to access the ctx.
12734 	 *
12735 	 * The exception is sys_perf_event_open() /
12736 	 * perf_event_create_kernel_count() which does find_get_context()
12737 	 * without ctx::mutex (it cannot because of the move_group double mutex
12738 	 * lock thing). See the comments in perf_install_in_context().
12739 	 */
12740 	mutex_lock(&child_ctx->mutex);
12741 
12742 	/*
12743 	 * In a single ctx::lock section, de-schedule the events and detach the
12744 	 * context from the task such that we cannot ever get it scheduled back
12745 	 * in.
12746 	 */
12747 	raw_spin_lock_irq(&child_ctx->lock);
12748 	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12749 
12750 	/*
12751 	 * Now that the context is inactive, destroy the task <-> ctx relation
12752 	 * and mark the context dead.
12753 	 */
12754 	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12755 	put_ctx(child_ctx); /* cannot be last */
12756 	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12757 	put_task_struct(current); /* cannot be last */
12758 
12759 	clone_ctx = unclone_ctx(child_ctx);
12760 	raw_spin_unlock_irq(&child_ctx->lock);
12761 
12762 	if (clone_ctx)
12763 		put_ctx(clone_ctx);
12764 
12765 	/*
12766 	 * Report the task dead after unscheduling the events so that we
12767 	 * won't get any samples after PERF_RECORD_EXIT. We can however still
12768 	 * get a few PERF_RECORD_READ events.
12769 	 */
12770 	perf_event_task(child, child_ctx, 0);
12771 
12772 	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12773 		perf_event_exit_event(child_event, child_ctx);
12774 
12775 	mutex_unlock(&child_ctx->mutex);
12776 
12777 	put_ctx(child_ctx);
12778 }
12779 
12780 /*
12781  * When a child task exits, feed back event values to parent events.
12782  *
12783  * Can be called with exec_update_lock held when called from
12784  * setup_new_exec().
12785  */
perf_event_exit_task(struct task_struct * child)12786 void perf_event_exit_task(struct task_struct *child)
12787 {
12788 	struct perf_event *event, *tmp;
12789 	int ctxn;
12790 
12791 	mutex_lock(&child->perf_event_mutex);
12792 	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12793 				 owner_entry) {
12794 		list_del_init(&event->owner_entry);
12795 
12796 		/*
12797 		 * Ensure the list deletion is visible before we clear
12798 		 * the owner, closes a race against perf_release() where
12799 		 * we need to serialize on the owner->perf_event_mutex.
12800 		 */
12801 		smp_store_release(&event->owner, NULL);
12802 	}
12803 	mutex_unlock(&child->perf_event_mutex);
12804 
12805 	for_each_task_context_nr(ctxn)
12806 		perf_event_exit_task_context(child, ctxn);
12807 
12808 	/*
12809 	 * The perf_event_exit_task_context calls perf_event_task
12810 	 * with child's task_ctx, which generates EXIT events for
12811 	 * child contexts and sets child->perf_event_ctxp[] to NULL.
12812 	 * At this point we need to send EXIT events to cpu contexts.
12813 	 */
12814 	perf_event_task(child, NULL, 0);
12815 }
12816 
perf_free_event(struct perf_event * event,struct perf_event_context * ctx)12817 static void perf_free_event(struct perf_event *event,
12818 			    struct perf_event_context *ctx)
12819 {
12820 	struct perf_event *parent = event->parent;
12821 
12822 	if (WARN_ON_ONCE(!parent))
12823 		return;
12824 
12825 	mutex_lock(&parent->child_mutex);
12826 	list_del_init(&event->child_list);
12827 	mutex_unlock(&parent->child_mutex);
12828 
12829 	put_event(parent);
12830 
12831 	raw_spin_lock_irq(&ctx->lock);
12832 	perf_group_detach(event);
12833 	list_del_event(event, ctx);
12834 	raw_spin_unlock_irq(&ctx->lock);
12835 	free_event(event);
12836 }
12837 
12838 /*
12839  * Free a context as created by inheritance by perf_event_init_task() below,
12840  * used by fork() in case of fail.
12841  *
12842  * Even though the task has never lived, the context and events have been
12843  * exposed through the child_list, so we must take care tearing it all down.
12844  */
perf_event_free_task(struct task_struct * task)12845 void perf_event_free_task(struct task_struct *task)
12846 {
12847 	struct perf_event_context *ctx;
12848 	struct perf_event *event, *tmp;
12849 	int ctxn;
12850 
12851 	for_each_task_context_nr(ctxn) {
12852 		ctx = task->perf_event_ctxp[ctxn];
12853 		if (!ctx)
12854 			continue;
12855 
12856 		mutex_lock(&ctx->mutex);
12857 		raw_spin_lock_irq(&ctx->lock);
12858 		/*
12859 		 * Destroy the task <-> ctx relation and mark the context dead.
12860 		 *
12861 		 * This is important because even though the task hasn't been
12862 		 * exposed yet the context has been (through child_list).
12863 		 */
12864 		RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12865 		WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12866 		put_task_struct(task); /* cannot be last */
12867 		raw_spin_unlock_irq(&ctx->lock);
12868 
12869 		list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12870 			perf_free_event(event, ctx);
12871 
12872 		mutex_unlock(&ctx->mutex);
12873 
12874 		/*
12875 		 * perf_event_release_kernel() could've stolen some of our
12876 		 * child events and still have them on its free_list. In that
12877 		 * case we must wait for these events to have been freed (in
12878 		 * particular all their references to this task must've been
12879 		 * dropped).
12880 		 *
12881 		 * Without this copy_process() will unconditionally free this
12882 		 * task (irrespective of its reference count) and
12883 		 * _free_event()'s put_task_struct(event->hw.target) will be a
12884 		 * use-after-free.
12885 		 *
12886 		 * Wait for all events to drop their context reference.
12887 		 */
12888 		wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12889 		put_ctx(ctx); /* must be last */
12890 	}
12891 }
12892 
perf_event_delayed_put(struct task_struct * task)12893 void perf_event_delayed_put(struct task_struct *task)
12894 {
12895 	int ctxn;
12896 
12897 	for_each_task_context_nr(ctxn)
12898 		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12899 }
12900 
perf_event_get(unsigned int fd)12901 struct file *perf_event_get(unsigned int fd)
12902 {
12903 	struct file *file = fget(fd);
12904 	if (!file)
12905 		return ERR_PTR(-EBADF);
12906 
12907 	if (file->f_op != &perf_fops) {
12908 		fput(file);
12909 		return ERR_PTR(-EBADF);
12910 	}
12911 
12912 	return file;
12913 }
12914 
perf_get_event(struct file * file)12915 const struct perf_event *perf_get_event(struct file *file)
12916 {
12917 	if (file->f_op != &perf_fops)
12918 		return ERR_PTR(-EINVAL);
12919 
12920 	return file->private_data;
12921 }
12922 
perf_event_attrs(struct perf_event * event)12923 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12924 {
12925 	if (!event)
12926 		return ERR_PTR(-EINVAL);
12927 
12928 	return &event->attr;
12929 }
12930 
12931 /*
12932  * Inherit an event from parent task to child task.
12933  *
12934  * Returns:
12935  *  - valid pointer on success
12936  *  - NULL for orphaned events
12937  *  - IS_ERR() on error
12938  */
12939 static struct perf_event *
inherit_event(struct perf_event * parent_event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,struct perf_event * group_leader,struct perf_event_context * child_ctx)12940 inherit_event(struct perf_event *parent_event,
12941 	      struct task_struct *parent,
12942 	      struct perf_event_context *parent_ctx,
12943 	      struct task_struct *child,
12944 	      struct perf_event *group_leader,
12945 	      struct perf_event_context *child_ctx)
12946 {
12947 	enum perf_event_state parent_state = parent_event->state;
12948 	struct perf_event *child_event;
12949 	unsigned long flags;
12950 
12951 	/*
12952 	 * Instead of creating recursive hierarchies of events,
12953 	 * we link inherited events back to the original parent,
12954 	 * which has a filp for sure, which we use as the reference
12955 	 * count:
12956 	 */
12957 	if (parent_event->parent)
12958 		parent_event = parent_event->parent;
12959 
12960 	child_event = perf_event_alloc(&parent_event->attr,
12961 					   parent_event->cpu,
12962 					   child,
12963 					   group_leader, parent_event,
12964 					   NULL, NULL, -1);
12965 	if (IS_ERR(child_event))
12966 		return child_event;
12967 
12968 
12969 	if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12970 	    !child_ctx->task_ctx_data) {
12971 		struct pmu *pmu = child_event->pmu;
12972 
12973 		child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12974 		if (!child_ctx->task_ctx_data) {
12975 			free_event(child_event);
12976 			return ERR_PTR(-ENOMEM);
12977 		}
12978 	}
12979 
12980 	/*
12981 	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12982 	 * must be under the same lock in order to serialize against
12983 	 * perf_event_release_kernel(), such that either we must observe
12984 	 * is_orphaned_event() or they will observe us on the child_list.
12985 	 */
12986 	mutex_lock(&parent_event->child_mutex);
12987 	if (is_orphaned_event(parent_event) ||
12988 	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
12989 		mutex_unlock(&parent_event->child_mutex);
12990 		/* task_ctx_data is freed with child_ctx */
12991 		free_event(child_event);
12992 		return NULL;
12993 	}
12994 
12995 	get_ctx(child_ctx);
12996 
12997 	/*
12998 	 * Make the child state follow the state of the parent event,
12999 	 * not its attr.disabled bit.  We hold the parent's mutex,
13000 	 * so we won't race with perf_event_{en, dis}able_family.
13001 	 */
13002 	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13003 		child_event->state = PERF_EVENT_STATE_INACTIVE;
13004 	else
13005 		child_event->state = PERF_EVENT_STATE_OFF;
13006 
13007 	if (parent_event->attr.freq) {
13008 		u64 sample_period = parent_event->hw.sample_period;
13009 		struct hw_perf_event *hwc = &child_event->hw;
13010 
13011 		hwc->sample_period = sample_period;
13012 		hwc->last_period   = sample_period;
13013 
13014 		local64_set(&hwc->period_left, sample_period);
13015 	}
13016 
13017 	child_event->ctx = child_ctx;
13018 	child_event->overflow_handler = parent_event->overflow_handler;
13019 	child_event->overflow_handler_context
13020 		= parent_event->overflow_handler_context;
13021 
13022 	/*
13023 	 * Precalculate sample_data sizes
13024 	 */
13025 	perf_event__header_size(child_event);
13026 	perf_event__id_header_size(child_event);
13027 
13028 	/*
13029 	 * Link it up in the child's context:
13030 	 */
13031 	raw_spin_lock_irqsave(&child_ctx->lock, flags);
13032 	add_event_to_ctx(child_event, child_ctx);
13033 	child_event->attach_state |= PERF_ATTACH_CHILD;
13034 	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13035 
13036 	/*
13037 	 * Link this into the parent event's child list
13038 	 */
13039 	list_add_tail(&child_event->child_list, &parent_event->child_list);
13040 	mutex_unlock(&parent_event->child_mutex);
13041 
13042 	return child_event;
13043 }
13044 
13045 /*
13046  * Inherits an event group.
13047  *
13048  * This will quietly suppress orphaned events; !inherit_event() is not an error.
13049  * This matches with perf_event_release_kernel() removing all child events.
13050  *
13051  * Returns:
13052  *  - 0 on success
13053  *  - <0 on error
13054  */
inherit_group(struct perf_event * parent_event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,struct perf_event_context * child_ctx)13055 static int inherit_group(struct perf_event *parent_event,
13056 	      struct task_struct *parent,
13057 	      struct perf_event_context *parent_ctx,
13058 	      struct task_struct *child,
13059 	      struct perf_event_context *child_ctx)
13060 {
13061 	struct perf_event *leader;
13062 	struct perf_event *sub;
13063 	struct perf_event *child_ctr;
13064 
13065 	leader = inherit_event(parent_event, parent, parent_ctx,
13066 				 child, NULL, child_ctx);
13067 	if (IS_ERR(leader))
13068 		return PTR_ERR(leader);
13069 	/*
13070 	 * @leader can be NULL here because of is_orphaned_event(). In this
13071 	 * case inherit_event() will create individual events, similar to what
13072 	 * perf_group_detach() would do anyway.
13073 	 */
13074 	for_each_sibling_event(sub, parent_event) {
13075 		child_ctr = inherit_event(sub, parent, parent_ctx,
13076 					    child, leader, child_ctx);
13077 		if (IS_ERR(child_ctr))
13078 			return PTR_ERR(child_ctr);
13079 
13080 		if (sub->aux_event == parent_event && child_ctr &&
13081 		    !perf_get_aux_event(child_ctr, leader))
13082 			return -EINVAL;
13083 	}
13084 	return 0;
13085 }
13086 
13087 /*
13088  * Creates the child task context and tries to inherit the event-group.
13089  *
13090  * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13091  * inherited_all set when we 'fail' to inherit an orphaned event; this is
13092  * consistent with perf_event_release_kernel() removing all child events.
13093  *
13094  * Returns:
13095  *  - 0 on success
13096  *  - <0 on error
13097  */
13098 static int
inherit_task_group(struct perf_event * event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,int ctxn,u64 clone_flags,int * inherited_all)13099 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13100 		   struct perf_event_context *parent_ctx,
13101 		   struct task_struct *child, int ctxn,
13102 		   u64 clone_flags, int *inherited_all)
13103 {
13104 	int ret;
13105 	struct perf_event_context *child_ctx;
13106 
13107 	if (!event->attr.inherit ||
13108 	    (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13109 	    /* Do not inherit if sigtrap and signal handlers were cleared. */
13110 	    (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13111 		*inherited_all = 0;
13112 		return 0;
13113 	}
13114 
13115 	child_ctx = child->perf_event_ctxp[ctxn];
13116 	if (!child_ctx) {
13117 		/*
13118 		 * This is executed from the parent task context, so
13119 		 * inherit events that have been marked for cloning.
13120 		 * First allocate and initialize a context for the
13121 		 * child.
13122 		 */
13123 		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13124 		if (!child_ctx)
13125 			return -ENOMEM;
13126 
13127 		child->perf_event_ctxp[ctxn] = child_ctx;
13128 	}
13129 
13130 	ret = inherit_group(event, parent, parent_ctx,
13131 			    child, child_ctx);
13132 
13133 	if (ret)
13134 		*inherited_all = 0;
13135 
13136 	return ret;
13137 }
13138 
13139 /*
13140  * Initialize the perf_event context in task_struct
13141  */
perf_event_init_context(struct task_struct * child,int ctxn,u64 clone_flags)13142 static int perf_event_init_context(struct task_struct *child, int ctxn,
13143 				   u64 clone_flags)
13144 {
13145 	struct perf_event_context *child_ctx, *parent_ctx;
13146 	struct perf_event_context *cloned_ctx;
13147 	struct perf_event *event;
13148 	struct task_struct *parent = current;
13149 	int inherited_all = 1;
13150 	unsigned long flags;
13151 	int ret = 0;
13152 
13153 	if (likely(!parent->perf_event_ctxp[ctxn]))
13154 		return 0;
13155 
13156 	/*
13157 	 * If the parent's context is a clone, pin it so it won't get
13158 	 * swapped under us.
13159 	 */
13160 	parent_ctx = perf_pin_task_context(parent, ctxn);
13161 	if (!parent_ctx)
13162 		return 0;
13163 
13164 	/*
13165 	 * No need to check if parent_ctx != NULL here; since we saw
13166 	 * it non-NULL earlier, the only reason for it to become NULL
13167 	 * is if we exit, and since we're currently in the middle of
13168 	 * a fork we can't be exiting at the same time.
13169 	 */
13170 
13171 	/*
13172 	 * Lock the parent list. No need to lock the child - not PID
13173 	 * hashed yet and not running, so nobody can access it.
13174 	 */
13175 	mutex_lock(&parent_ctx->mutex);
13176 
13177 	/*
13178 	 * We dont have to disable NMIs - we are only looking at
13179 	 * the list, not manipulating it:
13180 	 */
13181 	perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13182 		ret = inherit_task_group(event, parent, parent_ctx,
13183 					 child, ctxn, clone_flags,
13184 					 &inherited_all);
13185 		if (ret)
13186 			goto out_unlock;
13187 	}
13188 
13189 	/*
13190 	 * We can't hold ctx->lock when iterating the ->flexible_group list due
13191 	 * to allocations, but we need to prevent rotation because
13192 	 * rotate_ctx() will change the list from interrupt context.
13193 	 */
13194 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13195 	parent_ctx->rotate_disable = 1;
13196 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13197 
13198 	perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13199 		ret = inherit_task_group(event, parent, parent_ctx,
13200 					 child, ctxn, clone_flags,
13201 					 &inherited_all);
13202 		if (ret)
13203 			goto out_unlock;
13204 	}
13205 
13206 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13207 	parent_ctx->rotate_disable = 0;
13208 
13209 	child_ctx = child->perf_event_ctxp[ctxn];
13210 
13211 	if (child_ctx && inherited_all) {
13212 		/*
13213 		 * Mark the child context as a clone of the parent
13214 		 * context, or of whatever the parent is a clone of.
13215 		 *
13216 		 * Note that if the parent is a clone, the holding of
13217 		 * parent_ctx->lock avoids it from being uncloned.
13218 		 */
13219 		cloned_ctx = parent_ctx->parent_ctx;
13220 		if (cloned_ctx) {
13221 			child_ctx->parent_ctx = cloned_ctx;
13222 			child_ctx->parent_gen = parent_ctx->parent_gen;
13223 		} else {
13224 			child_ctx->parent_ctx = parent_ctx;
13225 			child_ctx->parent_gen = parent_ctx->generation;
13226 		}
13227 		get_ctx(child_ctx->parent_ctx);
13228 	}
13229 
13230 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13231 out_unlock:
13232 	mutex_unlock(&parent_ctx->mutex);
13233 
13234 	perf_unpin_context(parent_ctx);
13235 	put_ctx(parent_ctx);
13236 
13237 	return ret;
13238 }
13239 
13240 /*
13241  * Initialize the perf_event context in task_struct
13242  */
perf_event_init_task(struct task_struct * child,u64 clone_flags)13243 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13244 {
13245 	int ctxn, ret;
13246 
13247 	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13248 	mutex_init(&child->perf_event_mutex);
13249 	INIT_LIST_HEAD(&child->perf_event_list);
13250 
13251 	for_each_task_context_nr(ctxn) {
13252 		ret = perf_event_init_context(child, ctxn, clone_flags);
13253 		if (ret) {
13254 			perf_event_free_task(child);
13255 			return ret;
13256 		}
13257 	}
13258 
13259 	return 0;
13260 }
13261 
perf_event_init_all_cpus(void)13262 static void __init perf_event_init_all_cpus(void)
13263 {
13264 	struct swevent_htable *swhash;
13265 	int cpu;
13266 
13267 	zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13268 
13269 	for_each_possible_cpu(cpu) {
13270 		swhash = &per_cpu(swevent_htable, cpu);
13271 		mutex_init(&swhash->hlist_mutex);
13272 		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13273 
13274 		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13275 		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13276 
13277 #ifdef CONFIG_CGROUP_PERF
13278 		INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13279 #endif
13280 		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13281 	}
13282 }
13283 
perf_swevent_init_cpu(unsigned int cpu)13284 static void perf_swevent_init_cpu(unsigned int cpu)
13285 {
13286 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13287 
13288 	mutex_lock(&swhash->hlist_mutex);
13289 	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13290 		struct swevent_hlist *hlist;
13291 
13292 		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13293 		WARN_ON(!hlist);
13294 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
13295 	}
13296 	mutex_unlock(&swhash->hlist_mutex);
13297 }
13298 
13299 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
__perf_event_exit_context(void * __info)13300 static void __perf_event_exit_context(void *__info)
13301 {
13302 	struct perf_event_context *ctx = __info;
13303 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13304 	struct perf_event *event;
13305 
13306 	raw_spin_lock(&ctx->lock);
13307 	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13308 	list_for_each_entry(event, &ctx->event_list, event_entry)
13309 		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13310 	raw_spin_unlock(&ctx->lock);
13311 }
13312 
perf_event_exit_cpu_context(int cpu)13313 static void perf_event_exit_cpu_context(int cpu)
13314 {
13315 	struct perf_cpu_context *cpuctx;
13316 	struct perf_event_context *ctx;
13317 	struct pmu *pmu;
13318 
13319 	mutex_lock(&pmus_lock);
13320 	list_for_each_entry(pmu, &pmus, entry) {
13321 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13322 		ctx = &cpuctx->ctx;
13323 
13324 		mutex_lock(&ctx->mutex);
13325 		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13326 		cpuctx->online = 0;
13327 		mutex_unlock(&ctx->mutex);
13328 	}
13329 	cpumask_clear_cpu(cpu, perf_online_mask);
13330 	mutex_unlock(&pmus_lock);
13331 }
13332 #else
13333 
perf_event_exit_cpu_context(int cpu)13334 static void perf_event_exit_cpu_context(int cpu) { }
13335 
13336 #endif
13337 
perf_event_init_cpu(unsigned int cpu)13338 int perf_event_init_cpu(unsigned int cpu)
13339 {
13340 	struct perf_cpu_context *cpuctx;
13341 	struct perf_event_context *ctx;
13342 	struct pmu *pmu;
13343 
13344 	perf_swevent_init_cpu(cpu);
13345 
13346 	mutex_lock(&pmus_lock);
13347 	cpumask_set_cpu(cpu, perf_online_mask);
13348 	list_for_each_entry(pmu, &pmus, entry) {
13349 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13350 		ctx = &cpuctx->ctx;
13351 
13352 		mutex_lock(&ctx->mutex);
13353 		cpuctx->online = 1;
13354 		mutex_unlock(&ctx->mutex);
13355 	}
13356 	mutex_unlock(&pmus_lock);
13357 
13358 	return 0;
13359 }
13360 
perf_event_exit_cpu(unsigned int cpu)13361 int perf_event_exit_cpu(unsigned int cpu)
13362 {
13363 	perf_event_exit_cpu_context(cpu);
13364 	return 0;
13365 }
13366 
13367 static int
perf_reboot(struct notifier_block * notifier,unsigned long val,void * v)13368 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13369 {
13370 	int cpu;
13371 
13372 	for_each_online_cpu(cpu)
13373 		perf_event_exit_cpu(cpu);
13374 
13375 	return NOTIFY_OK;
13376 }
13377 
13378 /*
13379  * Run the perf reboot notifier at the very last possible moment so that
13380  * the generic watchdog code runs as long as possible.
13381  */
13382 static struct notifier_block perf_reboot_notifier = {
13383 	.notifier_call = perf_reboot,
13384 	.priority = INT_MIN,
13385 };
13386 
perf_event_init(void)13387 void __init perf_event_init(void)
13388 {
13389 	int ret;
13390 
13391 	idr_init(&pmu_idr);
13392 
13393 	perf_event_init_all_cpus();
13394 	init_srcu_struct(&pmus_srcu);
13395 	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13396 	perf_pmu_register(&perf_cpu_clock, NULL, -1);
13397 	perf_pmu_register(&perf_task_clock, NULL, -1);
13398 	perf_tp_register();
13399 	perf_event_init_cpu(smp_processor_id());
13400 	register_reboot_notifier(&perf_reboot_notifier);
13401 
13402 	ret = init_hw_breakpoint();
13403 	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13404 
13405 	perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13406 
13407 	/*
13408 	 * Build time assertion that we keep the data_head at the intended
13409 	 * location.  IOW, validation we got the __reserved[] size right.
13410 	 */
13411 	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13412 		     != 1024);
13413 }
13414 
perf_event_sysfs_show(struct device * dev,struct device_attribute * attr,char * page)13415 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13416 			      char *page)
13417 {
13418 	struct perf_pmu_events_attr *pmu_attr =
13419 		container_of(attr, struct perf_pmu_events_attr, attr);
13420 
13421 	if (pmu_attr->event_str)
13422 		return sprintf(page, "%s\n", pmu_attr->event_str);
13423 
13424 	return 0;
13425 }
13426 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13427 
perf_event_sysfs_init(void)13428 static int __init perf_event_sysfs_init(void)
13429 {
13430 	struct pmu *pmu;
13431 	int ret;
13432 
13433 	mutex_lock(&pmus_lock);
13434 
13435 	ret = bus_register(&pmu_bus);
13436 	if (ret)
13437 		goto unlock;
13438 
13439 	list_for_each_entry(pmu, &pmus, entry) {
13440 		if (!pmu->name || pmu->type < 0)
13441 			continue;
13442 
13443 		ret = pmu_dev_alloc(pmu);
13444 		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13445 	}
13446 	pmu_bus_running = 1;
13447 	ret = 0;
13448 
13449 unlock:
13450 	mutex_unlock(&pmus_lock);
13451 
13452 	return ret;
13453 }
13454 device_initcall(perf_event_sysfs_init);
13455 
13456 #ifdef CONFIG_CGROUP_PERF
13457 static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state * parent_css)13458 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13459 {
13460 	struct perf_cgroup *jc;
13461 
13462 	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13463 	if (!jc)
13464 		return ERR_PTR(-ENOMEM);
13465 
13466 	jc->info = alloc_percpu(struct perf_cgroup_info);
13467 	if (!jc->info) {
13468 		kfree(jc);
13469 		return ERR_PTR(-ENOMEM);
13470 	}
13471 
13472 	return &jc->css;
13473 }
13474 
perf_cgroup_css_free(struct cgroup_subsys_state * css)13475 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13476 {
13477 	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13478 
13479 	free_percpu(jc->info);
13480 	kfree(jc);
13481 }
13482 
perf_cgroup_css_online(struct cgroup_subsys_state * css)13483 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13484 {
13485 	perf_event_cgroup(css->cgroup);
13486 	return 0;
13487 }
13488 
__perf_cgroup_move(void * info)13489 static int __perf_cgroup_move(void *info)
13490 {
13491 	struct task_struct *task = info;
13492 	rcu_read_lock();
13493 	perf_cgroup_switch(task);
13494 	rcu_read_unlock();
13495 	return 0;
13496 }
13497 
perf_cgroup_attach(struct cgroup_taskset * tset)13498 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13499 {
13500 	struct task_struct *task;
13501 	struct cgroup_subsys_state *css;
13502 
13503 	cgroup_taskset_for_each(task, css, tset)
13504 		task_function_call(task, __perf_cgroup_move, task);
13505 }
13506 
13507 struct cgroup_subsys perf_event_cgrp_subsys = {
13508 	.css_alloc	= perf_cgroup_css_alloc,
13509 	.css_free	= perf_cgroup_css_free,
13510 	.css_online	= perf_cgroup_css_online,
13511 	.attach		= perf_cgroup_attach,
13512 	/*
13513 	 * Implicitly enable on dfl hierarchy so that perf events can
13514 	 * always be filtered by cgroup2 path as long as perf_event
13515 	 * controller is not mounted on a legacy hierarchy.
13516 	 */
13517 	.implicit_on_dfl = true,
13518 	.threaded	= true,
13519 };
13520 #endif /* CONFIG_CGROUP_PERF */
13521 
13522 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
13523