1 /*
2 * Infrastructure for profiling code inserted by 'gcc -pg'.
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally ported from the -rt patch by:
8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code in the latency_tracer, that is:
11 *
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 William Lee Irwin III
14 */
15
16 #include <linux/stop_machine.h>
17 #include <linux/clocksource.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/suspend.h>
21 #include <linux/debugfs.h>
22 #include <linux/hardirq.h>
23 #include <linux/kthread.h>
24 #include <linux/uaccess.h>
25 #include <linux/bsearch.h>
26 #include <linux/module.h>
27 #include <linux/ftrace.h>
28 #include <linux/sysctl.h>
29 #include <linux/slab.h>
30 #include <linux/ctype.h>
31 #include <linux/sort.h>
32 #include <linux/list.h>
33 #include <linux/hash.h>
34 #include <linux/rcupdate.h>
35
36 #include <trace/events/sched.h>
37
38 #include <asm/setup.h>
39
40 #include "trace_output.h"
41 #include "trace_stat.h"
42
43 #define FTRACE_WARN_ON(cond) \
44 ({ \
45 int ___r = cond; \
46 if (WARN_ON(___r)) \
47 ftrace_kill(); \
48 ___r; \
49 })
50
51 #define FTRACE_WARN_ON_ONCE(cond) \
52 ({ \
53 int ___r = cond; \
54 if (WARN_ON_ONCE(___r)) \
55 ftrace_kill(); \
56 ___r; \
57 })
58
59 /* hash bits for specific function selection */
60 #define FTRACE_HASH_BITS 7
61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62 #define FTRACE_HASH_DEFAULT_BITS 10
63 #define FTRACE_HASH_MAX_BITS 12
64
65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
66
67 /* ftrace_enabled is a method to turn ftrace on or off */
68 int ftrace_enabled __read_mostly;
69 static int last_ftrace_enabled;
70
71 /* Quick disabling of function tracer. */
72 int function_trace_stop;
73
74 /* List for set_ftrace_pid's pids. */
75 LIST_HEAD(ftrace_pids);
76 struct ftrace_pid {
77 struct list_head list;
78 struct pid *pid;
79 };
80
81 /*
82 * ftrace_disabled is set when an anomaly is discovered.
83 * ftrace_disabled is much stronger than ftrace_enabled.
84 */
85 static int ftrace_disabled __read_mostly;
86
87 static DEFINE_MUTEX(ftrace_lock);
88
89 static struct ftrace_ops ftrace_list_end __read_mostly = {
90 .func = ftrace_stub,
91 };
92
93 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
94 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
95 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
96 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
97 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
98 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
99 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
100 static struct ftrace_ops global_ops;
101 static struct ftrace_ops control_ops;
102
103 static void
104 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
105
106 /*
107 * Traverse the ftrace_global_list, invoking all entries. The reason that we
108 * can use rcu_dereference_raw() is that elements removed from this list
109 * are simply leaked, so there is no need to interact with a grace-period
110 * mechanism. The rcu_dereference_raw() calls are needed to handle
111 * concurrent insertions into the ftrace_global_list.
112 *
113 * Silly Alpha and silly pointer-speculation compiler optimizations!
114 */
ftrace_global_list_func(unsigned long ip,unsigned long parent_ip)115 static void ftrace_global_list_func(unsigned long ip,
116 unsigned long parent_ip)
117 {
118 struct ftrace_ops *op;
119
120 if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
121 return;
122
123 trace_recursion_set(TRACE_GLOBAL_BIT);
124 op = rcu_dereference_raw(ftrace_global_list); /*see above*/
125 while (op != &ftrace_list_end) {
126 op->func(ip, parent_ip);
127 op = rcu_dereference_raw(op->next); /*see above*/
128 };
129 trace_recursion_clear(TRACE_GLOBAL_BIT);
130 }
131
ftrace_pid_func(unsigned long ip,unsigned long parent_ip)132 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
133 {
134 if (!test_tsk_trace_trace(current))
135 return;
136
137 ftrace_pid_function(ip, parent_ip);
138 }
139
set_ftrace_pid_function(ftrace_func_t func)140 static void set_ftrace_pid_function(ftrace_func_t func)
141 {
142 /* do not set ftrace_pid_function to itself! */
143 if (func != ftrace_pid_func)
144 ftrace_pid_function = func;
145 }
146
147 /**
148 * clear_ftrace_function - reset the ftrace function
149 *
150 * This NULLs the ftrace function and in essence stops
151 * tracing. There may be lag
152 */
clear_ftrace_function(void)153 void clear_ftrace_function(void)
154 {
155 ftrace_trace_function = ftrace_stub;
156 __ftrace_trace_function = ftrace_stub;
157 __ftrace_trace_function_delay = ftrace_stub;
158 ftrace_pid_function = ftrace_stub;
159 }
160
161 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
162 /*
163 * For those archs that do not test ftrace_trace_stop in their
164 * mcount call site, we need to do it from C.
165 */
ftrace_test_stop_func(unsigned long ip,unsigned long parent_ip)166 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
167 {
168 if (function_trace_stop)
169 return;
170
171 __ftrace_trace_function(ip, parent_ip);
172 }
173 #endif
174
control_ops_disable_all(struct ftrace_ops * ops)175 static void control_ops_disable_all(struct ftrace_ops *ops)
176 {
177 int cpu;
178
179 for_each_possible_cpu(cpu)
180 *per_cpu_ptr(ops->disabled, cpu) = 1;
181 }
182
control_ops_alloc(struct ftrace_ops * ops)183 static int control_ops_alloc(struct ftrace_ops *ops)
184 {
185 int __percpu *disabled;
186
187 disabled = alloc_percpu(int);
188 if (!disabled)
189 return -ENOMEM;
190
191 ops->disabled = disabled;
192 control_ops_disable_all(ops);
193 return 0;
194 }
195
control_ops_free(struct ftrace_ops * ops)196 static void control_ops_free(struct ftrace_ops *ops)
197 {
198 free_percpu(ops->disabled);
199 }
200
update_global_ops(void)201 static void update_global_ops(void)
202 {
203 ftrace_func_t func;
204
205 /*
206 * If there's only one function registered, then call that
207 * function directly. Otherwise, we need to iterate over the
208 * registered callers.
209 */
210 if (ftrace_global_list == &ftrace_list_end ||
211 ftrace_global_list->next == &ftrace_list_end)
212 func = ftrace_global_list->func;
213 else
214 func = ftrace_global_list_func;
215
216 /* If we filter on pids, update to use the pid function */
217 if (!list_empty(&ftrace_pids)) {
218 set_ftrace_pid_function(func);
219 func = ftrace_pid_func;
220 }
221
222 global_ops.func = func;
223 }
224
ftrace_sync(struct work_struct * work)225 static void ftrace_sync(struct work_struct *work)
226 {
227 /*
228 * This function is just a stub to implement a hard force
229 * of synchronize_sched(). This requires synchronizing
230 * tasks even in userspace and idle.
231 *
232 * Yes, function tracing is rude.
233 */
234 }
235
ftrace_sync_ipi(void * data)236 static void ftrace_sync_ipi(void *data)
237 {
238 /* Probably not needed, but do it anyway */
239 smp_rmb();
240 }
241
242 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
243 static void update_function_graph_func(void);
244 #else
update_function_graph_func(void)245 static inline void update_function_graph_func(void) { }
246 #endif
247
update_ftrace_function(void)248 static void update_ftrace_function(void)
249 {
250 ftrace_func_t func;
251
252 update_global_ops();
253
254 /*
255 * If we are at the end of the list and this ops is
256 * not dynamic, then have the mcount trampoline call
257 * the function directly
258 */
259 if (ftrace_ops_list == &ftrace_list_end ||
260 (ftrace_ops_list->next == &ftrace_list_end &&
261 !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
262 func = ftrace_ops_list->func;
263 else
264 func = ftrace_ops_list_func;
265
266 update_function_graph_func();
267
268 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
269 ftrace_trace_function = func;
270 #else
271 #ifdef CONFIG_DYNAMIC_FTRACE
272 /* do not update till all functions have been modified */
273 __ftrace_trace_function_delay = func;
274 #else
275 __ftrace_trace_function = func;
276 #endif
277 ftrace_trace_function =
278 (func == ftrace_stub) ? func : ftrace_test_stop_func;
279 #endif
280 }
281
add_ftrace_ops(struct ftrace_ops ** list,struct ftrace_ops * ops)282 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
283 {
284 ops->next = *list;
285 /*
286 * We are entering ops into the list but another
287 * CPU might be walking that list. We need to make sure
288 * the ops->next pointer is valid before another CPU sees
289 * the ops pointer included into the list.
290 */
291 rcu_assign_pointer(*list, ops);
292 }
293
remove_ftrace_ops(struct ftrace_ops ** list,struct ftrace_ops * ops)294 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
295 {
296 struct ftrace_ops **p;
297
298 /*
299 * If we are removing the last function, then simply point
300 * to the ftrace_stub.
301 */
302 if (*list == ops && ops->next == &ftrace_list_end) {
303 *list = &ftrace_list_end;
304 return 0;
305 }
306
307 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
308 if (*p == ops)
309 break;
310
311 if (*p != ops)
312 return -1;
313
314 *p = (*p)->next;
315 return 0;
316 }
317
add_ftrace_list_ops(struct ftrace_ops ** list,struct ftrace_ops * main_ops,struct ftrace_ops * ops)318 static void add_ftrace_list_ops(struct ftrace_ops **list,
319 struct ftrace_ops *main_ops,
320 struct ftrace_ops *ops)
321 {
322 int first = *list == &ftrace_list_end;
323 add_ftrace_ops(list, ops);
324 if (first)
325 add_ftrace_ops(&ftrace_ops_list, main_ops);
326 }
327
remove_ftrace_list_ops(struct ftrace_ops ** list,struct ftrace_ops * main_ops,struct ftrace_ops * ops)328 static int remove_ftrace_list_ops(struct ftrace_ops **list,
329 struct ftrace_ops *main_ops,
330 struct ftrace_ops *ops)
331 {
332 int ret = remove_ftrace_ops(list, ops);
333 if (!ret && *list == &ftrace_list_end)
334 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
335 return ret;
336 }
337
__register_ftrace_function(struct ftrace_ops * ops)338 static int __register_ftrace_function(struct ftrace_ops *ops)
339 {
340 if (FTRACE_WARN_ON(ops == &global_ops))
341 return -EINVAL;
342
343 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
344 return -EBUSY;
345
346 /* We don't support both control and global flags set. */
347 if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
348 return -EINVAL;
349
350 if (!core_kernel_data((unsigned long)ops))
351 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
352
353 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
354 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
355 ops->flags |= FTRACE_OPS_FL_ENABLED;
356 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
357 if (control_ops_alloc(ops))
358 return -ENOMEM;
359 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
360 } else
361 add_ftrace_ops(&ftrace_ops_list, ops);
362
363 if (ftrace_enabled)
364 update_ftrace_function();
365
366 return 0;
367 }
368
__unregister_ftrace_function(struct ftrace_ops * ops)369 static int __unregister_ftrace_function(struct ftrace_ops *ops)
370 {
371 int ret;
372
373 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
374 return -EBUSY;
375
376 if (FTRACE_WARN_ON(ops == &global_ops))
377 return -EINVAL;
378
379 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
380 ret = remove_ftrace_list_ops(&ftrace_global_list,
381 &global_ops, ops);
382 if (!ret)
383 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
384 } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
385 ret = remove_ftrace_list_ops(&ftrace_control_list,
386 &control_ops, ops);
387 } else
388 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
389
390 if (ret < 0)
391 return ret;
392
393 if (ftrace_enabled)
394 update_ftrace_function();
395
396 return 0;
397 }
398
ftrace_update_pid_func(void)399 static void ftrace_update_pid_func(void)
400 {
401 /* Only do something if we are tracing something */
402 if (ftrace_trace_function == ftrace_stub)
403 return;
404
405 update_ftrace_function();
406 }
407
408 #ifdef CONFIG_FUNCTION_PROFILER
409 struct ftrace_profile {
410 struct hlist_node node;
411 unsigned long ip;
412 unsigned long counter;
413 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
414 unsigned long long time;
415 unsigned long long time_squared;
416 #endif
417 };
418
419 struct ftrace_profile_page {
420 struct ftrace_profile_page *next;
421 unsigned long index;
422 struct ftrace_profile records[];
423 };
424
425 struct ftrace_profile_stat {
426 atomic_t disabled;
427 struct hlist_head *hash;
428 struct ftrace_profile_page *pages;
429 struct ftrace_profile_page *start;
430 struct tracer_stat stat;
431 };
432
433 #define PROFILE_RECORDS_SIZE \
434 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
435
436 #define PROFILES_PER_PAGE \
437 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
438
439 static int ftrace_profile_bits __read_mostly;
440 static int ftrace_profile_enabled __read_mostly;
441
442 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
443 static DEFINE_MUTEX(ftrace_profile_lock);
444
445 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
446
447 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
448
449 static void *
function_stat_next(void * v,int idx)450 function_stat_next(void *v, int idx)
451 {
452 struct ftrace_profile *rec = v;
453 struct ftrace_profile_page *pg;
454
455 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
456
457 again:
458 if (idx != 0)
459 rec++;
460
461 if ((void *)rec >= (void *)&pg->records[pg->index]) {
462 pg = pg->next;
463 if (!pg)
464 return NULL;
465 rec = &pg->records[0];
466 if (!rec->counter)
467 goto again;
468 }
469
470 return rec;
471 }
472
function_stat_start(struct tracer_stat * trace)473 static void *function_stat_start(struct tracer_stat *trace)
474 {
475 struct ftrace_profile_stat *stat =
476 container_of(trace, struct ftrace_profile_stat, stat);
477
478 if (!stat || !stat->start)
479 return NULL;
480
481 return function_stat_next(&stat->start->records[0], 0);
482 }
483
484 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
485 /* function graph compares on total time */
function_stat_cmp(void * p1,void * p2)486 static int function_stat_cmp(void *p1, void *p2)
487 {
488 struct ftrace_profile *a = p1;
489 struct ftrace_profile *b = p2;
490
491 if (a->time < b->time)
492 return -1;
493 if (a->time > b->time)
494 return 1;
495 else
496 return 0;
497 }
498 #else
499 /* not function graph compares against hits */
function_stat_cmp(void * p1,void * p2)500 static int function_stat_cmp(void *p1, void *p2)
501 {
502 struct ftrace_profile *a = p1;
503 struct ftrace_profile *b = p2;
504
505 if (a->counter < b->counter)
506 return -1;
507 if (a->counter > b->counter)
508 return 1;
509 else
510 return 0;
511 }
512 #endif
513
function_stat_headers(struct seq_file * m)514 static int function_stat_headers(struct seq_file *m)
515 {
516 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
517 seq_printf(m, " Function "
518 "Hit Time Avg s^2\n"
519 " -------- "
520 "--- ---- --- ---\n");
521 #else
522 seq_printf(m, " Function Hit\n"
523 " -------- ---\n");
524 #endif
525 return 0;
526 }
527
function_stat_show(struct seq_file * m,void * v)528 static int function_stat_show(struct seq_file *m, void *v)
529 {
530 struct ftrace_profile *rec = v;
531 char str[KSYM_SYMBOL_LEN];
532 int ret = 0;
533 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
534 static struct trace_seq s;
535 unsigned long long avg;
536 unsigned long long stddev;
537 #endif
538 mutex_lock(&ftrace_profile_lock);
539
540 /* we raced with function_profile_reset() */
541 if (unlikely(rec->counter == 0)) {
542 ret = -EBUSY;
543 goto out;
544 }
545
546 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
547 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
548
549 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
550 seq_printf(m, " ");
551 avg = rec->time;
552 do_div(avg, rec->counter);
553
554 /* Sample standard deviation (s^2) */
555 if (rec->counter <= 1)
556 stddev = 0;
557 else {
558 stddev = rec->time_squared - rec->counter * avg * avg;
559 /*
560 * Divide only 1000 for ns^2 -> us^2 conversion.
561 * trace_print_graph_duration will divide 1000 again.
562 */
563 do_div(stddev, (rec->counter - 1) * 1000);
564 }
565
566 trace_seq_init(&s);
567 trace_print_graph_duration(rec->time, &s);
568 trace_seq_puts(&s, " ");
569 trace_print_graph_duration(avg, &s);
570 trace_seq_puts(&s, " ");
571 trace_print_graph_duration(stddev, &s);
572 trace_print_seq(m, &s);
573 #endif
574 seq_putc(m, '\n');
575 out:
576 mutex_unlock(&ftrace_profile_lock);
577
578 return ret;
579 }
580
ftrace_profile_reset(struct ftrace_profile_stat * stat)581 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
582 {
583 struct ftrace_profile_page *pg;
584
585 pg = stat->pages = stat->start;
586
587 while (pg) {
588 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
589 pg->index = 0;
590 pg = pg->next;
591 }
592
593 memset(stat->hash, 0,
594 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
595 }
596
ftrace_profile_pages_init(struct ftrace_profile_stat * stat)597 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
598 {
599 struct ftrace_profile_page *pg;
600 int functions;
601 int pages;
602 int i;
603
604 /* If we already allocated, do nothing */
605 if (stat->pages)
606 return 0;
607
608 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
609 if (!stat->pages)
610 return -ENOMEM;
611
612 #ifdef CONFIG_DYNAMIC_FTRACE
613 functions = ftrace_update_tot_cnt;
614 #else
615 /*
616 * We do not know the number of functions that exist because
617 * dynamic tracing is what counts them. With past experience
618 * we have around 20K functions. That should be more than enough.
619 * It is highly unlikely we will execute every function in
620 * the kernel.
621 */
622 functions = 20000;
623 #endif
624
625 pg = stat->start = stat->pages;
626
627 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
628
629 for (i = 1; i < pages; i++) {
630 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
631 if (!pg->next)
632 goto out_free;
633 pg = pg->next;
634 }
635
636 return 0;
637
638 out_free:
639 pg = stat->start;
640 while (pg) {
641 unsigned long tmp = (unsigned long)pg;
642
643 pg = pg->next;
644 free_page(tmp);
645 }
646
647 stat->pages = NULL;
648 stat->start = NULL;
649
650 return -ENOMEM;
651 }
652
ftrace_profile_init_cpu(int cpu)653 static int ftrace_profile_init_cpu(int cpu)
654 {
655 struct ftrace_profile_stat *stat;
656 int size;
657
658 stat = &per_cpu(ftrace_profile_stats, cpu);
659
660 if (stat->hash) {
661 /* If the profile is already created, simply reset it */
662 ftrace_profile_reset(stat);
663 return 0;
664 }
665
666 /*
667 * We are profiling all functions, but usually only a few thousand
668 * functions are hit. We'll make a hash of 1024 items.
669 */
670 size = FTRACE_PROFILE_HASH_SIZE;
671
672 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
673
674 if (!stat->hash)
675 return -ENOMEM;
676
677 if (!ftrace_profile_bits) {
678 size--;
679
680 for (; size; size >>= 1)
681 ftrace_profile_bits++;
682 }
683
684 /* Preallocate the function profiling pages */
685 if (ftrace_profile_pages_init(stat) < 0) {
686 kfree(stat->hash);
687 stat->hash = NULL;
688 return -ENOMEM;
689 }
690
691 return 0;
692 }
693
ftrace_profile_init(void)694 static int ftrace_profile_init(void)
695 {
696 int cpu;
697 int ret = 0;
698
699 for_each_possible_cpu(cpu) {
700 ret = ftrace_profile_init_cpu(cpu);
701 if (ret)
702 break;
703 }
704
705 return ret;
706 }
707
708 /* interrupts must be disabled */
709 static struct ftrace_profile *
ftrace_find_profiled_func(struct ftrace_profile_stat * stat,unsigned long ip)710 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
711 {
712 struct ftrace_profile *rec;
713 struct hlist_head *hhd;
714 struct hlist_node *n;
715 unsigned long key;
716
717 key = hash_long(ip, ftrace_profile_bits);
718 hhd = &stat->hash[key];
719
720 if (hlist_empty(hhd))
721 return NULL;
722
723 hlist_for_each_entry_rcu(rec, n, hhd, node) {
724 if (rec->ip == ip)
725 return rec;
726 }
727
728 return NULL;
729 }
730
ftrace_add_profile(struct ftrace_profile_stat * stat,struct ftrace_profile * rec)731 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
732 struct ftrace_profile *rec)
733 {
734 unsigned long key;
735
736 key = hash_long(rec->ip, ftrace_profile_bits);
737 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
738 }
739
740 /*
741 * The memory is already allocated, this simply finds a new record to use.
742 */
743 static struct ftrace_profile *
ftrace_profile_alloc(struct ftrace_profile_stat * stat,unsigned long ip)744 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
745 {
746 struct ftrace_profile *rec = NULL;
747
748 /* prevent recursion (from NMIs) */
749 if (atomic_inc_return(&stat->disabled) != 1)
750 goto out;
751
752 /*
753 * Try to find the function again since an NMI
754 * could have added it
755 */
756 rec = ftrace_find_profiled_func(stat, ip);
757 if (rec)
758 goto out;
759
760 if (stat->pages->index == PROFILES_PER_PAGE) {
761 if (!stat->pages->next)
762 goto out;
763 stat->pages = stat->pages->next;
764 }
765
766 rec = &stat->pages->records[stat->pages->index++];
767 rec->ip = ip;
768 ftrace_add_profile(stat, rec);
769
770 out:
771 atomic_dec(&stat->disabled);
772
773 return rec;
774 }
775
776 static void
function_profile_call(unsigned long ip,unsigned long parent_ip)777 function_profile_call(unsigned long ip, unsigned long parent_ip)
778 {
779 struct ftrace_profile_stat *stat;
780 struct ftrace_profile *rec;
781 unsigned long flags;
782
783 if (!ftrace_profile_enabled)
784 return;
785
786 local_irq_save(flags);
787
788 stat = &__get_cpu_var(ftrace_profile_stats);
789 if (!stat->hash || !ftrace_profile_enabled)
790 goto out;
791
792 rec = ftrace_find_profiled_func(stat, ip);
793 if (!rec) {
794 rec = ftrace_profile_alloc(stat, ip);
795 if (!rec)
796 goto out;
797 }
798
799 rec->counter++;
800 out:
801 local_irq_restore(flags);
802 }
803
804 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
profile_graph_entry(struct ftrace_graph_ent * trace)805 static int profile_graph_entry(struct ftrace_graph_ent *trace)
806 {
807 function_profile_call(trace->func, 0);
808 return 1;
809 }
810
profile_graph_return(struct ftrace_graph_ret * trace)811 static void profile_graph_return(struct ftrace_graph_ret *trace)
812 {
813 struct ftrace_profile_stat *stat;
814 unsigned long long calltime;
815 struct ftrace_profile *rec;
816 unsigned long flags;
817
818 local_irq_save(flags);
819 stat = &__get_cpu_var(ftrace_profile_stats);
820 if (!stat->hash || !ftrace_profile_enabled)
821 goto out;
822
823 /* If the calltime was zero'd ignore it */
824 if (!trace->calltime)
825 goto out;
826
827 calltime = trace->rettime - trace->calltime;
828
829 if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
830 int index;
831
832 index = trace->depth;
833
834 /* Append this call time to the parent time to subtract */
835 if (index)
836 current->ret_stack[index - 1].subtime += calltime;
837
838 if (current->ret_stack[index].subtime < calltime)
839 calltime -= current->ret_stack[index].subtime;
840 else
841 calltime = 0;
842 }
843
844 rec = ftrace_find_profiled_func(stat, trace->func);
845 if (rec) {
846 rec->time += calltime;
847 rec->time_squared += calltime * calltime;
848 }
849
850 out:
851 local_irq_restore(flags);
852 }
853
register_ftrace_profiler(void)854 static int register_ftrace_profiler(void)
855 {
856 return register_ftrace_graph(&profile_graph_return,
857 &profile_graph_entry);
858 }
859
unregister_ftrace_profiler(void)860 static void unregister_ftrace_profiler(void)
861 {
862 unregister_ftrace_graph();
863 }
864 #else
865 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
866 .func = function_profile_call,
867 };
868
register_ftrace_profiler(void)869 static int register_ftrace_profiler(void)
870 {
871 return register_ftrace_function(&ftrace_profile_ops);
872 }
873
unregister_ftrace_profiler(void)874 static void unregister_ftrace_profiler(void)
875 {
876 unregister_ftrace_function(&ftrace_profile_ops);
877 }
878 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
879
880 static ssize_t
ftrace_profile_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)881 ftrace_profile_write(struct file *filp, const char __user *ubuf,
882 size_t cnt, loff_t *ppos)
883 {
884 unsigned long val;
885 int ret;
886
887 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
888 if (ret)
889 return ret;
890
891 val = !!val;
892
893 mutex_lock(&ftrace_profile_lock);
894 if (ftrace_profile_enabled ^ val) {
895 if (val) {
896 ret = ftrace_profile_init();
897 if (ret < 0) {
898 cnt = ret;
899 goto out;
900 }
901
902 ret = register_ftrace_profiler();
903 if (ret < 0) {
904 cnt = ret;
905 goto out;
906 }
907 ftrace_profile_enabled = 1;
908 } else {
909 ftrace_profile_enabled = 0;
910 /*
911 * unregister_ftrace_profiler calls stop_machine
912 * so this acts like an synchronize_sched.
913 */
914 unregister_ftrace_profiler();
915 }
916 }
917 out:
918 mutex_unlock(&ftrace_profile_lock);
919
920 *ppos += cnt;
921
922 return cnt;
923 }
924
925 static ssize_t
ftrace_profile_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)926 ftrace_profile_read(struct file *filp, char __user *ubuf,
927 size_t cnt, loff_t *ppos)
928 {
929 char buf[64]; /* big enough to hold a number */
930 int r;
931
932 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
933 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
934 }
935
936 static const struct file_operations ftrace_profile_fops = {
937 .open = tracing_open_generic,
938 .read = ftrace_profile_read,
939 .write = ftrace_profile_write,
940 .llseek = default_llseek,
941 };
942
943 /* used to initialize the real stat files */
944 static struct tracer_stat function_stats __initdata = {
945 .name = "functions",
946 .stat_start = function_stat_start,
947 .stat_next = function_stat_next,
948 .stat_cmp = function_stat_cmp,
949 .stat_headers = function_stat_headers,
950 .stat_show = function_stat_show
951 };
952
ftrace_profile_debugfs(struct dentry * d_tracer)953 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
954 {
955 struct ftrace_profile_stat *stat;
956 struct dentry *entry;
957 char *name;
958 int ret;
959 int cpu;
960
961 for_each_possible_cpu(cpu) {
962 stat = &per_cpu(ftrace_profile_stats, cpu);
963
964 /* allocate enough for function name + cpu number */
965 name = kmalloc(32, GFP_KERNEL);
966 if (!name) {
967 /*
968 * The files created are permanent, if something happens
969 * we still do not free memory.
970 */
971 WARN(1,
972 "Could not allocate stat file for cpu %d\n",
973 cpu);
974 return;
975 }
976 stat->stat = function_stats;
977 snprintf(name, 32, "function%d", cpu);
978 stat->stat.name = name;
979 ret = register_stat_tracer(&stat->stat);
980 if (ret) {
981 WARN(1,
982 "Could not register function stat for cpu %d\n",
983 cpu);
984 kfree(name);
985 return;
986 }
987 }
988
989 entry = debugfs_create_file("function_profile_enabled", 0644,
990 d_tracer, NULL, &ftrace_profile_fops);
991 if (!entry)
992 pr_warning("Could not create debugfs "
993 "'function_profile_enabled' entry\n");
994 }
995
996 #else /* CONFIG_FUNCTION_PROFILER */
ftrace_profile_debugfs(struct dentry * d_tracer)997 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
998 {
999 }
1000 #endif /* CONFIG_FUNCTION_PROFILER */
1001
1002 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1003
1004 loff_t
ftrace_filter_lseek(struct file * file,loff_t offset,int whence)1005 ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
1006 {
1007 loff_t ret;
1008
1009 if (file->f_mode & FMODE_READ)
1010 ret = seq_lseek(file, offset, whence);
1011 else
1012 file->f_pos = ret = 1;
1013
1014 return ret;
1015 }
1016
1017 #ifdef CONFIG_DYNAMIC_FTRACE
1018
1019 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1020 # error Dynamic ftrace depends on MCOUNT_RECORD
1021 #endif
1022
1023 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1024
1025 struct ftrace_func_probe {
1026 struct hlist_node node;
1027 struct ftrace_probe_ops *ops;
1028 unsigned long flags;
1029 unsigned long ip;
1030 void *data;
1031 struct rcu_head rcu;
1032 };
1033
1034 struct ftrace_func_entry {
1035 struct hlist_node hlist;
1036 unsigned long ip;
1037 };
1038
1039 struct ftrace_hash {
1040 unsigned long size_bits;
1041 struct hlist_head *buckets;
1042 unsigned long count;
1043 struct rcu_head rcu;
1044 };
1045
1046 /*
1047 * We make these constant because no one should touch them,
1048 * but they are used as the default "empty hash", to avoid allocating
1049 * it all the time. These are in a read only section such that if
1050 * anyone does try to modify it, it will cause an exception.
1051 */
1052 static const struct hlist_head empty_buckets[1];
1053 static const struct ftrace_hash empty_hash = {
1054 .buckets = (struct hlist_head *)empty_buckets,
1055 };
1056 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1057
1058 static struct ftrace_ops global_ops = {
1059 .func = ftrace_stub,
1060 .notrace_hash = EMPTY_HASH,
1061 .filter_hash = EMPTY_HASH,
1062 };
1063
1064 static DEFINE_MUTEX(ftrace_regex_lock);
1065
1066 struct ftrace_page {
1067 struct ftrace_page *next;
1068 struct dyn_ftrace *records;
1069 int index;
1070 int size;
1071 };
1072
1073 static struct ftrace_page *ftrace_new_pgs;
1074
1075 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1076 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1077
1078 /* estimate from running different kernels */
1079 #define NR_TO_INIT 10000
1080
1081 static struct ftrace_page *ftrace_pages_start;
1082 static struct ftrace_page *ftrace_pages;
1083
ftrace_hash_empty(struct ftrace_hash * hash)1084 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1085 {
1086 return !hash || !hash->count;
1087 }
1088
1089 static struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash * hash,unsigned long ip)1090 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1091 {
1092 unsigned long key;
1093 struct ftrace_func_entry *entry;
1094 struct hlist_head *hhd;
1095 struct hlist_node *n;
1096
1097 if (ftrace_hash_empty(hash))
1098 return NULL;
1099
1100 if (hash->size_bits > 0)
1101 key = hash_long(ip, hash->size_bits);
1102 else
1103 key = 0;
1104
1105 hhd = &hash->buckets[key];
1106
1107 hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1108 if (entry->ip == ip)
1109 return entry;
1110 }
1111 return NULL;
1112 }
1113
__add_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1114 static void __add_hash_entry(struct ftrace_hash *hash,
1115 struct ftrace_func_entry *entry)
1116 {
1117 struct hlist_head *hhd;
1118 unsigned long key;
1119
1120 if (hash->size_bits)
1121 key = hash_long(entry->ip, hash->size_bits);
1122 else
1123 key = 0;
1124
1125 hhd = &hash->buckets[key];
1126 hlist_add_head(&entry->hlist, hhd);
1127 hash->count++;
1128 }
1129
add_hash_entry(struct ftrace_hash * hash,unsigned long ip)1130 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1131 {
1132 struct ftrace_func_entry *entry;
1133
1134 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1135 if (!entry)
1136 return -ENOMEM;
1137
1138 entry->ip = ip;
1139 __add_hash_entry(hash, entry);
1140
1141 return 0;
1142 }
1143
1144 static void
free_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1145 free_hash_entry(struct ftrace_hash *hash,
1146 struct ftrace_func_entry *entry)
1147 {
1148 hlist_del(&entry->hlist);
1149 kfree(entry);
1150 hash->count--;
1151 }
1152
1153 static void
remove_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1154 remove_hash_entry(struct ftrace_hash *hash,
1155 struct ftrace_func_entry *entry)
1156 {
1157 hlist_del(&entry->hlist);
1158 hash->count--;
1159 }
1160
ftrace_hash_clear(struct ftrace_hash * hash)1161 static void ftrace_hash_clear(struct ftrace_hash *hash)
1162 {
1163 struct hlist_head *hhd;
1164 struct hlist_node *tp, *tn;
1165 struct ftrace_func_entry *entry;
1166 int size = 1 << hash->size_bits;
1167 int i;
1168
1169 if (!hash->count)
1170 return;
1171
1172 for (i = 0; i < size; i++) {
1173 hhd = &hash->buckets[i];
1174 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1175 free_hash_entry(hash, entry);
1176 }
1177 FTRACE_WARN_ON(hash->count);
1178 }
1179
free_ftrace_hash(struct ftrace_hash * hash)1180 static void free_ftrace_hash(struct ftrace_hash *hash)
1181 {
1182 if (!hash || hash == EMPTY_HASH)
1183 return;
1184 ftrace_hash_clear(hash);
1185 kfree(hash->buckets);
1186 kfree(hash);
1187 }
1188
__free_ftrace_hash_rcu(struct rcu_head * rcu)1189 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1190 {
1191 struct ftrace_hash *hash;
1192
1193 hash = container_of(rcu, struct ftrace_hash, rcu);
1194 free_ftrace_hash(hash);
1195 }
1196
free_ftrace_hash_rcu(struct ftrace_hash * hash)1197 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1198 {
1199 if (!hash || hash == EMPTY_HASH)
1200 return;
1201 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1202 }
1203
ftrace_free_filter(struct ftrace_ops * ops)1204 void ftrace_free_filter(struct ftrace_ops *ops)
1205 {
1206 free_ftrace_hash(ops->filter_hash);
1207 free_ftrace_hash(ops->notrace_hash);
1208 }
1209
alloc_ftrace_hash(int size_bits)1210 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1211 {
1212 struct ftrace_hash *hash;
1213 int size;
1214
1215 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1216 if (!hash)
1217 return NULL;
1218
1219 size = 1 << size_bits;
1220 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1221
1222 if (!hash->buckets) {
1223 kfree(hash);
1224 return NULL;
1225 }
1226
1227 hash->size_bits = size_bits;
1228
1229 return hash;
1230 }
1231
1232 static struct ftrace_hash *
alloc_and_copy_ftrace_hash(int size_bits,struct ftrace_hash * hash)1233 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1234 {
1235 struct ftrace_func_entry *entry;
1236 struct ftrace_hash *new_hash;
1237 struct hlist_node *tp;
1238 int size;
1239 int ret;
1240 int i;
1241
1242 new_hash = alloc_ftrace_hash(size_bits);
1243 if (!new_hash)
1244 return NULL;
1245
1246 /* Empty hash? */
1247 if (ftrace_hash_empty(hash))
1248 return new_hash;
1249
1250 size = 1 << hash->size_bits;
1251 for (i = 0; i < size; i++) {
1252 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1253 ret = add_hash_entry(new_hash, entry->ip);
1254 if (ret < 0)
1255 goto free_hash;
1256 }
1257 }
1258
1259 FTRACE_WARN_ON(new_hash->count != hash->count);
1260
1261 return new_hash;
1262
1263 free_hash:
1264 free_ftrace_hash(new_hash);
1265 return NULL;
1266 }
1267
1268 static void
1269 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1270 static void
1271 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1272
1273 static int
ftrace_hash_move(struct ftrace_ops * ops,int enable,struct ftrace_hash ** dst,struct ftrace_hash * src)1274 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1275 struct ftrace_hash **dst, struct ftrace_hash *src)
1276 {
1277 struct ftrace_func_entry *entry;
1278 struct hlist_node *tp, *tn;
1279 struct hlist_head *hhd;
1280 struct ftrace_hash *old_hash;
1281 struct ftrace_hash *new_hash;
1282 unsigned long key;
1283 int size = src->count;
1284 int bits = 0;
1285 int ret;
1286 int i;
1287
1288 /*
1289 * Remove the current set, update the hash and add
1290 * them back.
1291 */
1292 ftrace_hash_rec_disable(ops, enable);
1293
1294 /*
1295 * If the new source is empty, just free dst and assign it
1296 * the empty_hash.
1297 */
1298 if (!src->count) {
1299 free_ftrace_hash_rcu(*dst);
1300 rcu_assign_pointer(*dst, EMPTY_HASH);
1301 /* still need to update the function records */
1302 ret = 0;
1303 goto out;
1304 }
1305
1306 /*
1307 * Make the hash size about 1/2 the # found
1308 */
1309 for (size /= 2; size; size >>= 1)
1310 bits++;
1311
1312 /* Don't allocate too much */
1313 if (bits > FTRACE_HASH_MAX_BITS)
1314 bits = FTRACE_HASH_MAX_BITS;
1315
1316 ret = -ENOMEM;
1317 new_hash = alloc_ftrace_hash(bits);
1318 if (!new_hash)
1319 goto out;
1320
1321 size = 1 << src->size_bits;
1322 for (i = 0; i < size; i++) {
1323 hhd = &src->buckets[i];
1324 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1325 if (bits > 0)
1326 key = hash_long(entry->ip, bits);
1327 else
1328 key = 0;
1329 remove_hash_entry(src, entry);
1330 __add_hash_entry(new_hash, entry);
1331 }
1332 }
1333
1334 old_hash = *dst;
1335 rcu_assign_pointer(*dst, new_hash);
1336 free_ftrace_hash_rcu(old_hash);
1337
1338 ret = 0;
1339 out:
1340 /*
1341 * Enable regardless of ret:
1342 * On success, we enable the new hash.
1343 * On failure, we re-enable the original hash.
1344 */
1345 ftrace_hash_rec_enable(ops, enable);
1346
1347 return ret;
1348 }
1349
1350 /*
1351 * Test the hashes for this ops to see if we want to call
1352 * the ops->func or not.
1353 *
1354 * It's a match if the ip is in the ops->filter_hash or
1355 * the filter_hash does not exist or is empty,
1356 * AND
1357 * the ip is not in the ops->notrace_hash.
1358 *
1359 * This needs to be called with preemption disabled as
1360 * the hashes are freed with call_rcu_sched().
1361 */
1362 static int
ftrace_ops_test(struct ftrace_ops * ops,unsigned long ip)1363 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1364 {
1365 struct ftrace_hash *filter_hash;
1366 struct ftrace_hash *notrace_hash;
1367 int ret;
1368
1369 filter_hash = rcu_dereference_raw(ops->filter_hash);
1370 notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1371
1372 if ((ftrace_hash_empty(filter_hash) ||
1373 ftrace_lookup_ip(filter_hash, ip)) &&
1374 (ftrace_hash_empty(notrace_hash) ||
1375 !ftrace_lookup_ip(notrace_hash, ip)))
1376 ret = 1;
1377 else
1378 ret = 0;
1379
1380 return ret;
1381 }
1382
1383 /*
1384 * This is a double for. Do not use 'break' to break out of the loop,
1385 * you must use a goto.
1386 */
1387 #define do_for_each_ftrace_rec(pg, rec) \
1388 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1389 int _____i; \
1390 for (_____i = 0; _____i < pg->index; _____i++) { \
1391 rec = &pg->records[_____i];
1392
1393 #define while_for_each_ftrace_rec() \
1394 } \
1395 }
1396
1397
ftrace_cmp_recs(const void * a,const void * b)1398 static int ftrace_cmp_recs(const void *a, const void *b)
1399 {
1400 const struct dyn_ftrace *reca = a;
1401 const struct dyn_ftrace *recb = b;
1402
1403 if (reca->ip > recb->ip)
1404 return 1;
1405 if (reca->ip < recb->ip)
1406 return -1;
1407 return 0;
1408 }
1409
1410 /**
1411 * ftrace_location - return true if the ip giving is a traced location
1412 * @ip: the instruction pointer to check
1413 *
1414 * Returns 1 if @ip given is a pointer to a ftrace location.
1415 * That is, the instruction that is either a NOP or call to
1416 * the function tracer. It checks the ftrace internal tables to
1417 * determine if the address belongs or not.
1418 */
ftrace_location(unsigned long ip)1419 int ftrace_location(unsigned long ip)
1420 {
1421 struct ftrace_page *pg;
1422 struct dyn_ftrace *rec;
1423 struct dyn_ftrace key;
1424
1425 key.ip = ip;
1426
1427 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1428 rec = bsearch(&key, pg->records, pg->index,
1429 sizeof(struct dyn_ftrace),
1430 ftrace_cmp_recs);
1431 if (rec)
1432 return 1;
1433 }
1434
1435 return 0;
1436 }
1437
__ftrace_hash_rec_update(struct ftrace_ops * ops,int filter_hash,bool inc)1438 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1439 int filter_hash,
1440 bool inc)
1441 {
1442 struct ftrace_hash *hash;
1443 struct ftrace_hash *other_hash;
1444 struct ftrace_page *pg;
1445 struct dyn_ftrace *rec;
1446 int count = 0;
1447 int all = 0;
1448
1449 /* Only update if the ops has been registered */
1450 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1451 return;
1452
1453 /*
1454 * In the filter_hash case:
1455 * If the count is zero, we update all records.
1456 * Otherwise we just update the items in the hash.
1457 *
1458 * In the notrace_hash case:
1459 * We enable the update in the hash.
1460 * As disabling notrace means enabling the tracing,
1461 * and enabling notrace means disabling, the inc variable
1462 * gets inversed.
1463 */
1464 if (filter_hash) {
1465 hash = ops->filter_hash;
1466 other_hash = ops->notrace_hash;
1467 if (ftrace_hash_empty(hash))
1468 all = 1;
1469 } else {
1470 inc = !inc;
1471 hash = ops->notrace_hash;
1472 other_hash = ops->filter_hash;
1473 /*
1474 * If the notrace hash has no items,
1475 * then there's nothing to do.
1476 */
1477 if (ftrace_hash_empty(hash))
1478 return;
1479 }
1480
1481 do_for_each_ftrace_rec(pg, rec) {
1482 int in_other_hash = 0;
1483 int in_hash = 0;
1484 int match = 0;
1485
1486 if (all) {
1487 /*
1488 * Only the filter_hash affects all records.
1489 * Update if the record is not in the notrace hash.
1490 */
1491 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1492 match = 1;
1493 } else {
1494 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1495 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1496
1497 /*
1498 *
1499 */
1500 if (filter_hash && in_hash && !in_other_hash)
1501 match = 1;
1502 else if (!filter_hash && in_hash &&
1503 (in_other_hash || ftrace_hash_empty(other_hash)))
1504 match = 1;
1505 }
1506 if (!match)
1507 continue;
1508
1509 if (inc) {
1510 rec->flags++;
1511 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1512 return;
1513 } else {
1514 if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1515 return;
1516 rec->flags--;
1517 }
1518 count++;
1519 /* Shortcut, if we handled all records, we are done. */
1520 if (!all && count == hash->count)
1521 return;
1522 } while_for_each_ftrace_rec();
1523 }
1524
ftrace_hash_rec_disable(struct ftrace_ops * ops,int filter_hash)1525 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1526 int filter_hash)
1527 {
1528 __ftrace_hash_rec_update(ops, filter_hash, 0);
1529 }
1530
ftrace_hash_rec_enable(struct ftrace_ops * ops,int filter_hash)1531 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1532 int filter_hash)
1533 {
1534 __ftrace_hash_rec_update(ops, filter_hash, 1);
1535 }
1536
ftrace_alloc_dyn_node(unsigned long ip)1537 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1538 {
1539 if (ftrace_pages->index == ftrace_pages->size) {
1540 /* We should have allocated enough */
1541 if (WARN_ON(!ftrace_pages->next))
1542 return NULL;
1543 ftrace_pages = ftrace_pages->next;
1544 }
1545
1546 return &ftrace_pages->records[ftrace_pages->index++];
1547 }
1548
1549 static struct dyn_ftrace *
ftrace_record_ip(unsigned long ip)1550 ftrace_record_ip(unsigned long ip)
1551 {
1552 struct dyn_ftrace *rec;
1553
1554 if (ftrace_disabled)
1555 return NULL;
1556
1557 rec = ftrace_alloc_dyn_node(ip);
1558 if (!rec)
1559 return NULL;
1560
1561 rec->ip = ip;
1562
1563 return rec;
1564 }
1565
print_ip_ins(const char * fmt,unsigned char * p)1566 static void print_ip_ins(const char *fmt, unsigned char *p)
1567 {
1568 int i;
1569
1570 printk(KERN_CONT "%s", fmt);
1571
1572 for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1573 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1574 }
1575
1576 /**
1577 * ftrace_bug - report and shutdown function tracer
1578 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1579 * @ip: The address that failed
1580 *
1581 * The arch code that enables or disables the function tracing
1582 * can call ftrace_bug() when it has detected a problem in
1583 * modifying the code. @failed should be one of either:
1584 * EFAULT - if the problem happens on reading the @ip address
1585 * EINVAL - if what is read at @ip is not what was expected
1586 * EPERM - if the problem happens on writting to the @ip address
1587 */
ftrace_bug(int failed,unsigned long ip)1588 void ftrace_bug(int failed, unsigned long ip)
1589 {
1590 switch (failed) {
1591 case -EFAULT:
1592 FTRACE_WARN_ON_ONCE(1);
1593 pr_info("ftrace faulted on modifying ");
1594 print_ip_sym(ip);
1595 break;
1596 case -EINVAL:
1597 FTRACE_WARN_ON_ONCE(1);
1598 pr_info("ftrace failed to modify ");
1599 print_ip_sym(ip);
1600 print_ip_ins(" actual: ", (unsigned char *)ip);
1601 printk(KERN_CONT "\n");
1602 break;
1603 case -EPERM:
1604 FTRACE_WARN_ON_ONCE(1);
1605 pr_info("ftrace faulted on writing ");
1606 print_ip_sym(ip);
1607 break;
1608 default:
1609 FTRACE_WARN_ON_ONCE(1);
1610 pr_info("ftrace faulted on unknown error ");
1611 print_ip_sym(ip);
1612 }
1613 }
1614
1615
1616 /* Return 1 if the address range is reserved for ftrace */
ftrace_text_reserved(void * start,void * end)1617 int ftrace_text_reserved(void *start, void *end)
1618 {
1619 struct dyn_ftrace *rec;
1620 struct ftrace_page *pg;
1621
1622 do_for_each_ftrace_rec(pg, rec) {
1623 if (rec->ip <= (unsigned long)end &&
1624 rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1625 return 1;
1626 } while_for_each_ftrace_rec();
1627 return 0;
1628 }
1629
ftrace_check_record(struct dyn_ftrace * rec,int enable,int update)1630 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1631 {
1632 unsigned long flag = 0UL;
1633
1634 /*
1635 * If we are updating calls:
1636 *
1637 * If the record has a ref count, then we need to enable it
1638 * because someone is using it.
1639 *
1640 * Otherwise we make sure its disabled.
1641 *
1642 * If we are disabling calls, then disable all records that
1643 * are enabled.
1644 */
1645 if (enable && (rec->flags & ~FTRACE_FL_MASK))
1646 flag = FTRACE_FL_ENABLED;
1647
1648 /* If the state of this record hasn't changed, then do nothing */
1649 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1650 return FTRACE_UPDATE_IGNORE;
1651
1652 if (flag) {
1653 if (update)
1654 rec->flags |= FTRACE_FL_ENABLED;
1655 return FTRACE_UPDATE_MAKE_CALL;
1656 }
1657
1658 if (update)
1659 rec->flags &= ~FTRACE_FL_ENABLED;
1660
1661 return FTRACE_UPDATE_MAKE_NOP;
1662 }
1663
1664 /**
1665 * ftrace_update_record, set a record that now is tracing or not
1666 * @rec: the record to update
1667 * @enable: set to 1 if the record is tracing, zero to force disable
1668 *
1669 * The records that represent all functions that can be traced need
1670 * to be updated when tracing has been enabled.
1671 */
ftrace_update_record(struct dyn_ftrace * rec,int enable)1672 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1673 {
1674 return ftrace_check_record(rec, enable, 1);
1675 }
1676
1677 /**
1678 * ftrace_test_record, check if the record has been enabled or not
1679 * @rec: the record to test
1680 * @enable: set to 1 to check if enabled, 0 if it is disabled
1681 *
1682 * The arch code may need to test if a record is already set to
1683 * tracing to determine how to modify the function code that it
1684 * represents.
1685 */
ftrace_test_record(struct dyn_ftrace * rec,int enable)1686 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1687 {
1688 return ftrace_check_record(rec, enable, 0);
1689 }
1690
1691 static int
__ftrace_replace_code(struct dyn_ftrace * rec,int enable)1692 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1693 {
1694 unsigned long ftrace_addr;
1695 int ret;
1696
1697 ftrace_addr = (unsigned long)FTRACE_ADDR;
1698
1699 ret = ftrace_update_record(rec, enable);
1700
1701 switch (ret) {
1702 case FTRACE_UPDATE_IGNORE:
1703 return 0;
1704
1705 case FTRACE_UPDATE_MAKE_CALL:
1706 return ftrace_make_call(rec, ftrace_addr);
1707
1708 case FTRACE_UPDATE_MAKE_NOP:
1709 return ftrace_make_nop(NULL, rec, ftrace_addr);
1710 }
1711
1712 return -1; /* unknow ftrace bug */
1713 }
1714
ftrace_replace_code(int update)1715 static void ftrace_replace_code(int update)
1716 {
1717 struct dyn_ftrace *rec;
1718 struct ftrace_page *pg;
1719 int failed;
1720
1721 if (unlikely(ftrace_disabled))
1722 return;
1723
1724 do_for_each_ftrace_rec(pg, rec) {
1725 failed = __ftrace_replace_code(rec, update);
1726 if (failed) {
1727 ftrace_bug(failed, rec->ip);
1728 /* Stop processing */
1729 return;
1730 }
1731 } while_for_each_ftrace_rec();
1732 }
1733
1734 struct ftrace_rec_iter {
1735 struct ftrace_page *pg;
1736 int index;
1737 };
1738
1739 /**
1740 * ftrace_rec_iter_start, start up iterating over traced functions
1741 *
1742 * Returns an iterator handle that is used to iterate over all
1743 * the records that represent address locations where functions
1744 * are traced.
1745 *
1746 * May return NULL if no records are available.
1747 */
ftrace_rec_iter_start(void)1748 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1749 {
1750 /*
1751 * We only use a single iterator.
1752 * Protected by the ftrace_lock mutex.
1753 */
1754 static struct ftrace_rec_iter ftrace_rec_iter;
1755 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1756
1757 iter->pg = ftrace_pages_start;
1758 iter->index = 0;
1759
1760 /* Could have empty pages */
1761 while (iter->pg && !iter->pg->index)
1762 iter->pg = iter->pg->next;
1763
1764 if (!iter->pg)
1765 return NULL;
1766
1767 return iter;
1768 }
1769
1770 /**
1771 * ftrace_rec_iter_next, get the next record to process.
1772 * @iter: The handle to the iterator.
1773 *
1774 * Returns the next iterator after the given iterator @iter.
1775 */
ftrace_rec_iter_next(struct ftrace_rec_iter * iter)1776 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1777 {
1778 iter->index++;
1779
1780 if (iter->index >= iter->pg->index) {
1781 iter->pg = iter->pg->next;
1782 iter->index = 0;
1783
1784 /* Could have empty pages */
1785 while (iter->pg && !iter->pg->index)
1786 iter->pg = iter->pg->next;
1787 }
1788
1789 if (!iter->pg)
1790 return NULL;
1791
1792 return iter;
1793 }
1794
1795 /**
1796 * ftrace_rec_iter_record, get the record at the iterator location
1797 * @iter: The current iterator location
1798 *
1799 * Returns the record that the current @iter is at.
1800 */
ftrace_rec_iter_record(struct ftrace_rec_iter * iter)1801 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1802 {
1803 return &iter->pg->records[iter->index];
1804 }
1805
1806 static int
ftrace_code_disable(struct module * mod,struct dyn_ftrace * rec)1807 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1808 {
1809 unsigned long ip;
1810 int ret;
1811
1812 ip = rec->ip;
1813
1814 if (unlikely(ftrace_disabled))
1815 return 0;
1816
1817 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1818 if (ret) {
1819 ftrace_bug(ret, ip);
1820 return 0;
1821 }
1822 return 1;
1823 }
1824
1825 /*
1826 * archs can override this function if they must do something
1827 * before the modifying code is performed.
1828 */
ftrace_arch_code_modify_prepare(void)1829 int __weak ftrace_arch_code_modify_prepare(void)
1830 {
1831 return 0;
1832 }
1833
1834 /*
1835 * archs can override this function if they must do something
1836 * after the modifying code is performed.
1837 */
ftrace_arch_code_modify_post_process(void)1838 int __weak ftrace_arch_code_modify_post_process(void)
1839 {
1840 return 0;
1841 }
1842
__ftrace_modify_code(void * data)1843 static int __ftrace_modify_code(void *data)
1844 {
1845 int *command = data;
1846
1847 if (*command & FTRACE_UPDATE_CALLS)
1848 ftrace_replace_code(1);
1849 else if (*command & FTRACE_DISABLE_CALLS)
1850 ftrace_replace_code(0);
1851
1852 if (*command & FTRACE_UPDATE_TRACE_FUNC)
1853 ftrace_update_ftrace_func(ftrace_trace_function);
1854
1855 if (*command & FTRACE_START_FUNC_RET)
1856 ftrace_enable_ftrace_graph_caller();
1857 else if (*command & FTRACE_STOP_FUNC_RET)
1858 ftrace_disable_ftrace_graph_caller();
1859
1860 return 0;
1861 }
1862
1863 /**
1864 * ftrace_run_stop_machine, go back to the stop machine method
1865 * @command: The command to tell ftrace what to do
1866 *
1867 * If an arch needs to fall back to the stop machine method, the
1868 * it can call this function.
1869 */
ftrace_run_stop_machine(int command)1870 void ftrace_run_stop_machine(int command)
1871 {
1872 stop_machine(__ftrace_modify_code, &command, NULL);
1873 }
1874
1875 /**
1876 * arch_ftrace_update_code, modify the code to trace or not trace
1877 * @command: The command that needs to be done
1878 *
1879 * Archs can override this function if it does not need to
1880 * run stop_machine() to modify code.
1881 */
arch_ftrace_update_code(int command)1882 void __weak arch_ftrace_update_code(int command)
1883 {
1884 ftrace_run_stop_machine(command);
1885 }
1886
ftrace_run_update_code(int command)1887 static void ftrace_run_update_code(int command)
1888 {
1889 int ret;
1890
1891 ret = ftrace_arch_code_modify_prepare();
1892 FTRACE_WARN_ON(ret);
1893 if (ret)
1894 return;
1895 /*
1896 * Do not call function tracer while we update the code.
1897 * We are in stop machine.
1898 */
1899 function_trace_stop++;
1900
1901 /*
1902 * By default we use stop_machine() to modify the code.
1903 * But archs can do what ever they want as long as it
1904 * is safe. The stop_machine() is the safest, but also
1905 * produces the most overhead.
1906 */
1907 arch_ftrace_update_code(command);
1908
1909 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1910 /*
1911 * For archs that call ftrace_test_stop_func(), we must
1912 * wait till after we update all the function callers
1913 * before we update the callback. This keeps different
1914 * ops that record different functions from corrupting
1915 * each other.
1916 */
1917 __ftrace_trace_function = __ftrace_trace_function_delay;
1918 #endif
1919 function_trace_stop--;
1920
1921 ret = ftrace_arch_code_modify_post_process();
1922 FTRACE_WARN_ON(ret);
1923 }
1924
1925 static ftrace_func_t saved_ftrace_func;
1926 static int ftrace_start_up;
1927 static int global_start_up;
1928
ftrace_startup_enable(int command)1929 static void ftrace_startup_enable(int command)
1930 {
1931 if (saved_ftrace_func != ftrace_trace_function) {
1932 saved_ftrace_func = ftrace_trace_function;
1933 command |= FTRACE_UPDATE_TRACE_FUNC;
1934 }
1935
1936 if (!command || !ftrace_enabled)
1937 return;
1938
1939 ftrace_run_update_code(command);
1940 }
1941
ftrace_startup(struct ftrace_ops * ops,int command)1942 static int ftrace_startup(struct ftrace_ops *ops, int command)
1943 {
1944 bool hash_enable = true;
1945 int ret;
1946
1947 if (unlikely(ftrace_disabled))
1948 return -ENODEV;
1949
1950 ret = __register_ftrace_function(ops);
1951 if (ret)
1952 return ret;
1953
1954 ftrace_start_up++;
1955 command |= FTRACE_UPDATE_CALLS;
1956
1957 /* ops marked global share the filter hashes */
1958 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1959 ops = &global_ops;
1960 /* Don't update hash if global is already set */
1961 if (global_start_up)
1962 hash_enable = false;
1963 global_start_up++;
1964 }
1965
1966 ops->flags |= FTRACE_OPS_FL_ENABLED;
1967 if (hash_enable)
1968 ftrace_hash_rec_enable(ops, 1);
1969
1970 ftrace_startup_enable(command);
1971
1972 return 0;
1973 }
1974
ftrace_shutdown(struct ftrace_ops * ops,int command)1975 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
1976 {
1977 bool hash_disable = true;
1978 int ret;
1979
1980 if (unlikely(ftrace_disabled))
1981 return -ENODEV;
1982
1983 ret = __unregister_ftrace_function(ops);
1984 if (ret)
1985 return ret;
1986
1987 ftrace_start_up--;
1988 /*
1989 * Just warn in case of unbalance, no need to kill ftrace, it's not
1990 * critical but the ftrace_call callers may be never nopped again after
1991 * further ftrace uses.
1992 */
1993 WARN_ON_ONCE(ftrace_start_up < 0);
1994
1995 if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1996 ops = &global_ops;
1997 global_start_up--;
1998 WARN_ON_ONCE(global_start_up < 0);
1999 /* Don't update hash if global still has users */
2000 if (global_start_up) {
2001 WARN_ON_ONCE(!ftrace_start_up);
2002 hash_disable = false;
2003 }
2004 }
2005
2006 if (hash_disable)
2007 ftrace_hash_rec_disable(ops, 1);
2008
2009 if (ops != &global_ops || !global_start_up)
2010 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2011
2012 command |= FTRACE_UPDATE_CALLS;
2013
2014 if (saved_ftrace_func != ftrace_trace_function) {
2015 saved_ftrace_func = ftrace_trace_function;
2016 command |= FTRACE_UPDATE_TRACE_FUNC;
2017 }
2018
2019 if (!command || !ftrace_enabled) {
2020 /*
2021 * If these are control ops, they still need their
2022 * per_cpu field freed. Since, function tracing is
2023 * not currently active, we can just free them
2024 * without synchronizing all CPUs.
2025 */
2026 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2027 control_ops_free(ops);
2028 return 0;
2029 }
2030
2031 ftrace_run_update_code(command);
2032
2033 /*
2034 * Dynamic ops may be freed, we must make sure that all
2035 * callers are done before leaving this function.
2036 * The same goes for freeing the per_cpu data of the control
2037 * ops.
2038 *
2039 * Again, normal synchronize_sched() is not good enough.
2040 * We need to do a hard force of sched synchronization.
2041 * This is because we use preempt_disable() to do RCU, but
2042 * the function tracers can be called where RCU is not watching
2043 * (like before user_exit()). We can not rely on the RCU
2044 * infrastructure to do the synchronization, thus we must do it
2045 * ourselves.
2046 */
2047 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2048 schedule_on_each_cpu(ftrace_sync);
2049
2050 if (ops->flags & FTRACE_OPS_FL_CONTROL)
2051 control_ops_free(ops);
2052 }
2053
2054 return 0;
2055 }
2056
ftrace_startup_sysctl(void)2057 static void ftrace_startup_sysctl(void)
2058 {
2059 if (unlikely(ftrace_disabled))
2060 return;
2061
2062 /* Force update next time */
2063 saved_ftrace_func = NULL;
2064 /* ftrace_start_up is true if we want ftrace running */
2065 if (ftrace_start_up)
2066 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2067 }
2068
ftrace_shutdown_sysctl(void)2069 static void ftrace_shutdown_sysctl(void)
2070 {
2071 if (unlikely(ftrace_disabled))
2072 return;
2073
2074 /* ftrace_start_up is true if ftrace is running */
2075 if (ftrace_start_up)
2076 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2077 }
2078
2079 static cycle_t ftrace_update_time;
2080 static unsigned long ftrace_update_cnt;
2081 unsigned long ftrace_update_tot_cnt;
2082
ops_traces_mod(struct ftrace_ops * ops)2083 static inline int ops_traces_mod(struct ftrace_ops *ops)
2084 {
2085 /*
2086 * Filter_hash being empty will default to trace module.
2087 * But notrace hash requires a test of individual module functions.
2088 */
2089 return ftrace_hash_empty(ops->filter_hash) &&
2090 ftrace_hash_empty(ops->notrace_hash);
2091 }
2092
2093 /*
2094 * Check if the current ops references the record.
2095 *
2096 * If the ops traces all functions, then it was already accounted for.
2097 * If the ops does not trace the current record function, skip it.
2098 * If the ops ignores the function via notrace filter, skip it.
2099 */
2100 static inline bool
ops_references_rec(struct ftrace_ops * ops,struct dyn_ftrace * rec)2101 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2102 {
2103 /* If ops isn't enabled, ignore it */
2104 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2105 return 0;
2106
2107 /* If ops traces all mods, we already accounted for it */
2108 if (ops_traces_mod(ops))
2109 return 0;
2110
2111 /* The function must be in the filter */
2112 if (!ftrace_hash_empty(ops->filter_hash) &&
2113 !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2114 return 0;
2115
2116 /* If in notrace hash, we ignore it too */
2117 if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2118 return 0;
2119
2120 return 1;
2121 }
2122
referenced_filters(struct dyn_ftrace * rec)2123 static int referenced_filters(struct dyn_ftrace *rec)
2124 {
2125 struct ftrace_ops *ops;
2126 int cnt = 0;
2127
2128 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2129 if (ops_references_rec(ops, rec))
2130 cnt++;
2131 }
2132
2133 return cnt;
2134 }
2135
ftrace_update_code(struct module * mod)2136 static int ftrace_update_code(struct module *mod)
2137 {
2138 struct ftrace_page *pg;
2139 struct dyn_ftrace *p;
2140 cycle_t start, stop;
2141 unsigned long ref = 0;
2142 bool test = false;
2143 int i;
2144
2145 /*
2146 * When adding a module, we need to check if tracers are
2147 * currently enabled and if they are set to trace all functions.
2148 * If they are, we need to enable the module functions as well
2149 * as update the reference counts for those function records.
2150 */
2151 if (mod) {
2152 struct ftrace_ops *ops;
2153
2154 for (ops = ftrace_ops_list;
2155 ops != &ftrace_list_end; ops = ops->next) {
2156 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2157 if (ops_traces_mod(ops))
2158 ref++;
2159 else
2160 test = true;
2161 }
2162 }
2163 }
2164
2165 start = ftrace_now(raw_smp_processor_id());
2166 ftrace_update_cnt = 0;
2167
2168 for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2169
2170 for (i = 0; i < pg->index; i++) {
2171 int cnt = ref;
2172
2173 /* If something went wrong, bail without enabling anything */
2174 if (unlikely(ftrace_disabled))
2175 return -1;
2176
2177 p = &pg->records[i];
2178 if (test)
2179 cnt += referenced_filters(p);
2180 p->flags = cnt;
2181
2182 /*
2183 * Do the initial record conversion from mcount jump
2184 * to the NOP instructions.
2185 */
2186 if (!ftrace_code_disable(mod, p))
2187 break;
2188
2189 ftrace_update_cnt++;
2190
2191 /*
2192 * If the tracing is enabled, go ahead and enable the record.
2193 *
2194 * The reason not to enable the record immediatelly is the
2195 * inherent check of ftrace_make_nop/ftrace_make_call for
2196 * correct previous instructions. Making first the NOP
2197 * conversion puts the module to the correct state, thus
2198 * passing the ftrace_make_call check.
2199 */
2200 if (ftrace_start_up && cnt) {
2201 int failed = __ftrace_replace_code(p, 1);
2202 if (failed)
2203 ftrace_bug(failed, p->ip);
2204 }
2205 }
2206 }
2207
2208 ftrace_new_pgs = NULL;
2209
2210 stop = ftrace_now(raw_smp_processor_id());
2211 ftrace_update_time = stop - start;
2212 ftrace_update_tot_cnt += ftrace_update_cnt;
2213
2214 return 0;
2215 }
2216
ftrace_allocate_records(struct ftrace_page * pg,int count)2217 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2218 {
2219 int order;
2220 int cnt;
2221
2222 if (WARN_ON(!count))
2223 return -EINVAL;
2224
2225 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2226
2227 /*
2228 * We want to fill as much as possible. No more than a page
2229 * may be empty.
2230 */
2231 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2232 order--;
2233
2234 again:
2235 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2236
2237 if (!pg->records) {
2238 /* if we can't allocate this size, try something smaller */
2239 if (!order)
2240 return -ENOMEM;
2241 order >>= 1;
2242 goto again;
2243 }
2244
2245 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2246 pg->size = cnt;
2247
2248 if (cnt > count)
2249 cnt = count;
2250
2251 return cnt;
2252 }
2253
2254 static struct ftrace_page *
ftrace_allocate_pages(unsigned long num_to_init)2255 ftrace_allocate_pages(unsigned long num_to_init)
2256 {
2257 struct ftrace_page *start_pg;
2258 struct ftrace_page *pg;
2259 int order;
2260 int cnt;
2261
2262 if (!num_to_init)
2263 return 0;
2264
2265 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2266 if (!pg)
2267 return NULL;
2268
2269 /*
2270 * Try to allocate as much as possible in one continues
2271 * location that fills in all of the space. We want to
2272 * waste as little space as possible.
2273 */
2274 for (;;) {
2275 cnt = ftrace_allocate_records(pg, num_to_init);
2276 if (cnt < 0)
2277 goto free_pages;
2278
2279 num_to_init -= cnt;
2280 if (!num_to_init)
2281 break;
2282
2283 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2284 if (!pg->next)
2285 goto free_pages;
2286
2287 pg = pg->next;
2288 }
2289
2290 return start_pg;
2291
2292 free_pages:
2293 while (start_pg) {
2294 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2295 free_pages((unsigned long)pg->records, order);
2296 start_pg = pg->next;
2297 kfree(pg);
2298 pg = start_pg;
2299 }
2300 pr_info("ftrace: FAILED to allocate memory for functions\n");
2301 return NULL;
2302 }
2303
ftrace_dyn_table_alloc(unsigned long num_to_init)2304 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2305 {
2306 int cnt;
2307
2308 if (!num_to_init) {
2309 pr_info("ftrace: No functions to be traced?\n");
2310 return -1;
2311 }
2312
2313 cnt = num_to_init / ENTRIES_PER_PAGE;
2314 pr_info("ftrace: allocating %ld entries in %d pages\n",
2315 num_to_init, cnt + 1);
2316
2317 return 0;
2318 }
2319
2320 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2321
2322 struct ftrace_iterator {
2323 loff_t pos;
2324 loff_t func_pos;
2325 struct ftrace_page *pg;
2326 struct dyn_ftrace *func;
2327 struct ftrace_func_probe *probe;
2328 struct trace_parser parser;
2329 struct ftrace_hash *hash;
2330 struct ftrace_ops *ops;
2331 int hidx;
2332 int idx;
2333 unsigned flags;
2334 };
2335
2336 static void *
t_hash_next(struct seq_file * m,loff_t * pos)2337 t_hash_next(struct seq_file *m, loff_t *pos)
2338 {
2339 struct ftrace_iterator *iter = m->private;
2340 struct hlist_node *hnd = NULL;
2341 struct hlist_head *hhd;
2342
2343 (*pos)++;
2344 iter->pos = *pos;
2345
2346 if (iter->probe)
2347 hnd = &iter->probe->node;
2348 retry:
2349 if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2350 return NULL;
2351
2352 hhd = &ftrace_func_hash[iter->hidx];
2353
2354 if (hlist_empty(hhd)) {
2355 iter->hidx++;
2356 hnd = NULL;
2357 goto retry;
2358 }
2359
2360 if (!hnd)
2361 hnd = hhd->first;
2362 else {
2363 hnd = hnd->next;
2364 if (!hnd) {
2365 iter->hidx++;
2366 goto retry;
2367 }
2368 }
2369
2370 if (WARN_ON_ONCE(!hnd))
2371 return NULL;
2372
2373 iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2374
2375 return iter;
2376 }
2377
t_hash_start(struct seq_file * m,loff_t * pos)2378 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2379 {
2380 struct ftrace_iterator *iter = m->private;
2381 void *p = NULL;
2382 loff_t l;
2383
2384 if (!(iter->flags & FTRACE_ITER_DO_HASH))
2385 return NULL;
2386
2387 if (iter->func_pos > *pos)
2388 return NULL;
2389
2390 iter->hidx = 0;
2391 for (l = 0; l <= (*pos - iter->func_pos); ) {
2392 p = t_hash_next(m, &l);
2393 if (!p)
2394 break;
2395 }
2396 if (!p)
2397 return NULL;
2398
2399 /* Only set this if we have an item */
2400 iter->flags |= FTRACE_ITER_HASH;
2401
2402 return iter;
2403 }
2404
2405 static int
t_hash_show(struct seq_file * m,struct ftrace_iterator * iter)2406 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2407 {
2408 struct ftrace_func_probe *rec;
2409
2410 rec = iter->probe;
2411 if (WARN_ON_ONCE(!rec))
2412 return -EIO;
2413
2414 if (rec->ops->print)
2415 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2416
2417 seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2418
2419 if (rec->data)
2420 seq_printf(m, ":%p", rec->data);
2421 seq_putc(m, '\n');
2422
2423 return 0;
2424 }
2425
2426 static void *
t_next(struct seq_file * m,void * v,loff_t * pos)2427 t_next(struct seq_file *m, void *v, loff_t *pos)
2428 {
2429 struct ftrace_iterator *iter = m->private;
2430 struct ftrace_ops *ops = iter->ops;
2431 struct dyn_ftrace *rec = NULL;
2432
2433 if (unlikely(ftrace_disabled))
2434 return NULL;
2435
2436 if (iter->flags & FTRACE_ITER_HASH)
2437 return t_hash_next(m, pos);
2438
2439 (*pos)++;
2440 iter->pos = iter->func_pos = *pos;
2441
2442 if (iter->flags & FTRACE_ITER_PRINTALL)
2443 return t_hash_start(m, pos);
2444
2445 retry:
2446 if (iter->idx >= iter->pg->index) {
2447 if (iter->pg->next) {
2448 iter->pg = iter->pg->next;
2449 iter->idx = 0;
2450 goto retry;
2451 }
2452 } else {
2453 rec = &iter->pg->records[iter->idx++];
2454 if (((iter->flags & FTRACE_ITER_FILTER) &&
2455 !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2456
2457 ((iter->flags & FTRACE_ITER_NOTRACE) &&
2458 !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2459
2460 ((iter->flags & FTRACE_ITER_ENABLED) &&
2461 !(rec->flags & ~FTRACE_FL_MASK))) {
2462
2463 rec = NULL;
2464 goto retry;
2465 }
2466 }
2467
2468 if (!rec)
2469 return t_hash_start(m, pos);
2470
2471 iter->func = rec;
2472
2473 return iter;
2474 }
2475
reset_iter_read(struct ftrace_iterator * iter)2476 static void reset_iter_read(struct ftrace_iterator *iter)
2477 {
2478 iter->pos = 0;
2479 iter->func_pos = 0;
2480 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2481 }
2482
t_start(struct seq_file * m,loff_t * pos)2483 static void *t_start(struct seq_file *m, loff_t *pos)
2484 {
2485 struct ftrace_iterator *iter = m->private;
2486 struct ftrace_ops *ops = iter->ops;
2487 void *p = NULL;
2488 loff_t l;
2489
2490 mutex_lock(&ftrace_lock);
2491
2492 if (unlikely(ftrace_disabled))
2493 return NULL;
2494
2495 /*
2496 * If an lseek was done, then reset and start from beginning.
2497 */
2498 if (*pos < iter->pos)
2499 reset_iter_read(iter);
2500
2501 /*
2502 * For set_ftrace_filter reading, if we have the filter
2503 * off, we can short cut and just print out that all
2504 * functions are enabled.
2505 */
2506 if (iter->flags & FTRACE_ITER_FILTER &&
2507 ftrace_hash_empty(ops->filter_hash)) {
2508 if (*pos > 0)
2509 return t_hash_start(m, pos);
2510 iter->flags |= FTRACE_ITER_PRINTALL;
2511 /* reset in case of seek/pread */
2512 iter->flags &= ~FTRACE_ITER_HASH;
2513 return iter;
2514 }
2515
2516 if (iter->flags & FTRACE_ITER_HASH)
2517 return t_hash_start(m, pos);
2518
2519 /*
2520 * Unfortunately, we need to restart at ftrace_pages_start
2521 * every time we let go of the ftrace_mutex. This is because
2522 * those pointers can change without the lock.
2523 */
2524 iter->pg = ftrace_pages_start;
2525 iter->idx = 0;
2526 for (l = 0; l <= *pos; ) {
2527 p = t_next(m, p, &l);
2528 if (!p)
2529 break;
2530 }
2531
2532 if (!p)
2533 return t_hash_start(m, pos);
2534
2535 return iter;
2536 }
2537
t_stop(struct seq_file * m,void * p)2538 static void t_stop(struct seq_file *m, void *p)
2539 {
2540 mutex_unlock(&ftrace_lock);
2541 }
2542
t_show(struct seq_file * m,void * v)2543 static int t_show(struct seq_file *m, void *v)
2544 {
2545 struct ftrace_iterator *iter = m->private;
2546 struct dyn_ftrace *rec;
2547
2548 if (iter->flags & FTRACE_ITER_HASH)
2549 return t_hash_show(m, iter);
2550
2551 if (iter->flags & FTRACE_ITER_PRINTALL) {
2552 seq_printf(m, "#### all functions enabled ####\n");
2553 return 0;
2554 }
2555
2556 rec = iter->func;
2557
2558 if (!rec)
2559 return 0;
2560
2561 seq_printf(m, "%ps", (void *)rec->ip);
2562 if (iter->flags & FTRACE_ITER_ENABLED)
2563 seq_printf(m, " (%ld)",
2564 rec->flags & ~FTRACE_FL_MASK);
2565 seq_printf(m, "\n");
2566
2567 return 0;
2568 }
2569
2570 static const struct seq_operations show_ftrace_seq_ops = {
2571 .start = t_start,
2572 .next = t_next,
2573 .stop = t_stop,
2574 .show = t_show,
2575 };
2576
2577 static int
ftrace_avail_open(struct inode * inode,struct file * file)2578 ftrace_avail_open(struct inode *inode, struct file *file)
2579 {
2580 struct ftrace_iterator *iter;
2581 int ret;
2582
2583 if (unlikely(ftrace_disabled))
2584 return -ENODEV;
2585
2586 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2587 if (!iter)
2588 return -ENOMEM;
2589
2590 iter->pg = ftrace_pages_start;
2591 iter->ops = &global_ops;
2592
2593 ret = seq_open(file, &show_ftrace_seq_ops);
2594 if (!ret) {
2595 struct seq_file *m = file->private_data;
2596
2597 m->private = iter;
2598 } else {
2599 kfree(iter);
2600 }
2601
2602 return ret;
2603 }
2604
2605 static int
ftrace_enabled_open(struct inode * inode,struct file * file)2606 ftrace_enabled_open(struct inode *inode, struct file *file)
2607 {
2608 struct ftrace_iterator *iter;
2609 int ret;
2610
2611 if (unlikely(ftrace_disabled))
2612 return -ENODEV;
2613
2614 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2615 if (!iter)
2616 return -ENOMEM;
2617
2618 iter->pg = ftrace_pages_start;
2619 iter->flags = FTRACE_ITER_ENABLED;
2620 iter->ops = &global_ops;
2621
2622 ret = seq_open(file, &show_ftrace_seq_ops);
2623 if (!ret) {
2624 struct seq_file *m = file->private_data;
2625
2626 m->private = iter;
2627 } else {
2628 kfree(iter);
2629 }
2630
2631 return ret;
2632 }
2633
ftrace_filter_reset(struct ftrace_hash * hash)2634 static void ftrace_filter_reset(struct ftrace_hash *hash)
2635 {
2636 mutex_lock(&ftrace_lock);
2637 ftrace_hash_clear(hash);
2638 mutex_unlock(&ftrace_lock);
2639 }
2640
2641 /**
2642 * ftrace_regex_open - initialize function tracer filter files
2643 * @ops: The ftrace_ops that hold the hash filters
2644 * @flag: The type of filter to process
2645 * @inode: The inode, usually passed in to your open routine
2646 * @file: The file, usually passed in to your open routine
2647 *
2648 * ftrace_regex_open() initializes the filter files for the
2649 * @ops. Depending on @flag it may process the filter hash or
2650 * the notrace hash of @ops. With this called from the open
2651 * routine, you can use ftrace_filter_write() for the write
2652 * routine if @flag has FTRACE_ITER_FILTER set, or
2653 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2654 * ftrace_filter_lseek() should be used as the lseek routine, and
2655 * release must call ftrace_regex_release().
2656 */
2657 int
ftrace_regex_open(struct ftrace_ops * ops,int flag,struct inode * inode,struct file * file)2658 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2659 struct inode *inode, struct file *file)
2660 {
2661 struct ftrace_iterator *iter;
2662 struct ftrace_hash *hash;
2663 int ret = 0;
2664
2665 if (unlikely(ftrace_disabled))
2666 return -ENODEV;
2667
2668 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2669 if (!iter)
2670 return -ENOMEM;
2671
2672 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2673 kfree(iter);
2674 return -ENOMEM;
2675 }
2676
2677 if (flag & FTRACE_ITER_NOTRACE)
2678 hash = ops->notrace_hash;
2679 else
2680 hash = ops->filter_hash;
2681
2682 iter->ops = ops;
2683 iter->flags = flag;
2684
2685 if (file->f_mode & FMODE_WRITE) {
2686 mutex_lock(&ftrace_lock);
2687 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2688 mutex_unlock(&ftrace_lock);
2689
2690 if (!iter->hash) {
2691 trace_parser_put(&iter->parser);
2692 kfree(iter);
2693 return -ENOMEM;
2694 }
2695 }
2696
2697 mutex_lock(&ftrace_regex_lock);
2698
2699 if ((file->f_mode & FMODE_WRITE) &&
2700 (file->f_flags & O_TRUNC))
2701 ftrace_filter_reset(iter->hash);
2702
2703 if (file->f_mode & FMODE_READ) {
2704 iter->pg = ftrace_pages_start;
2705
2706 ret = seq_open(file, &show_ftrace_seq_ops);
2707 if (!ret) {
2708 struct seq_file *m = file->private_data;
2709 m->private = iter;
2710 } else {
2711 /* Failed */
2712 free_ftrace_hash(iter->hash);
2713 trace_parser_put(&iter->parser);
2714 kfree(iter);
2715 }
2716 } else
2717 file->private_data = iter;
2718 mutex_unlock(&ftrace_regex_lock);
2719
2720 return ret;
2721 }
2722
2723 static int
ftrace_filter_open(struct inode * inode,struct file * file)2724 ftrace_filter_open(struct inode *inode, struct file *file)
2725 {
2726 return ftrace_regex_open(&global_ops,
2727 FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2728 inode, file);
2729 }
2730
2731 static int
ftrace_notrace_open(struct inode * inode,struct file * file)2732 ftrace_notrace_open(struct inode *inode, struct file *file)
2733 {
2734 return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2735 inode, file);
2736 }
2737
ftrace_match(char * str,char * regex,int len,int type)2738 static int ftrace_match(char *str, char *regex, int len, int type)
2739 {
2740 int matched = 0;
2741 int slen;
2742
2743 switch (type) {
2744 case MATCH_FULL:
2745 if (strcmp(str, regex) == 0)
2746 matched = 1;
2747 break;
2748 case MATCH_FRONT_ONLY:
2749 if (strncmp(str, regex, len) == 0)
2750 matched = 1;
2751 break;
2752 case MATCH_MIDDLE_ONLY:
2753 if (strstr(str, regex))
2754 matched = 1;
2755 break;
2756 case MATCH_END_ONLY:
2757 slen = strlen(str);
2758 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2759 matched = 1;
2760 break;
2761 }
2762
2763 return matched;
2764 }
2765
2766 static int
enter_record(struct ftrace_hash * hash,struct dyn_ftrace * rec,int not)2767 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2768 {
2769 struct ftrace_func_entry *entry;
2770 int ret = 0;
2771
2772 entry = ftrace_lookup_ip(hash, rec->ip);
2773 if (not) {
2774 /* Do nothing if it doesn't exist */
2775 if (!entry)
2776 return 0;
2777
2778 free_hash_entry(hash, entry);
2779 } else {
2780 /* Do nothing if it exists */
2781 if (entry)
2782 return 0;
2783
2784 ret = add_hash_entry(hash, rec->ip);
2785 }
2786 return ret;
2787 }
2788
2789 static int
ftrace_match_record(struct dyn_ftrace * rec,char * mod,char * regex,int len,int type)2790 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2791 char *regex, int len, int type)
2792 {
2793 char str[KSYM_SYMBOL_LEN];
2794 char *modname;
2795
2796 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2797
2798 if (mod) {
2799 /* module lookup requires matching the module */
2800 if (!modname || strcmp(modname, mod))
2801 return 0;
2802
2803 /* blank search means to match all funcs in the mod */
2804 if (!len)
2805 return 1;
2806 }
2807
2808 return ftrace_match(str, regex, len, type);
2809 }
2810
2811 static int
match_records(struct ftrace_hash * hash,char * buff,int len,char * mod,int not)2812 match_records(struct ftrace_hash *hash, char *buff,
2813 int len, char *mod, int not)
2814 {
2815 unsigned search_len = 0;
2816 struct ftrace_page *pg;
2817 struct dyn_ftrace *rec;
2818 int type = MATCH_FULL;
2819 char *search = buff;
2820 int found = 0;
2821 int ret;
2822
2823 if (len) {
2824 type = filter_parse_regex(buff, len, &search, ¬);
2825 search_len = strlen(search);
2826 }
2827
2828 mutex_lock(&ftrace_lock);
2829
2830 if (unlikely(ftrace_disabled))
2831 goto out_unlock;
2832
2833 do_for_each_ftrace_rec(pg, rec) {
2834 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2835 ret = enter_record(hash, rec, not);
2836 if (ret < 0) {
2837 found = ret;
2838 goto out_unlock;
2839 }
2840 found = 1;
2841 }
2842 } while_for_each_ftrace_rec();
2843 out_unlock:
2844 mutex_unlock(&ftrace_lock);
2845
2846 return found;
2847 }
2848
2849 static int
ftrace_match_records(struct ftrace_hash * hash,char * buff,int len)2850 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2851 {
2852 return match_records(hash, buff, len, NULL, 0);
2853 }
2854
2855 static int
ftrace_match_module_records(struct ftrace_hash * hash,char * buff,char * mod)2856 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2857 {
2858 int not = 0;
2859
2860 /* blank or '*' mean the same */
2861 if (strcmp(buff, "*") == 0)
2862 buff[0] = 0;
2863
2864 /* handle the case of 'dont filter this module' */
2865 if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2866 buff[0] = 0;
2867 not = 1;
2868 }
2869
2870 return match_records(hash, buff, strlen(buff), mod, not);
2871 }
2872
2873 /*
2874 * We register the module command as a template to show others how
2875 * to register the a command as well.
2876 */
2877
2878 static int
ftrace_mod_callback(struct ftrace_hash * hash,char * func,char * cmd,char * param,int enable)2879 ftrace_mod_callback(struct ftrace_hash *hash,
2880 char *func, char *cmd, char *param, int enable)
2881 {
2882 char *mod;
2883 int ret = -EINVAL;
2884
2885 /*
2886 * cmd == 'mod' because we only registered this func
2887 * for the 'mod' ftrace_func_command.
2888 * But if you register one func with multiple commands,
2889 * you can tell which command was used by the cmd
2890 * parameter.
2891 */
2892
2893 /* we must have a module name */
2894 if (!param)
2895 return ret;
2896
2897 mod = strsep(¶m, ":");
2898 if (!strlen(mod))
2899 return ret;
2900
2901 ret = ftrace_match_module_records(hash, func, mod);
2902 if (!ret)
2903 ret = -EINVAL;
2904 if (ret < 0)
2905 return ret;
2906
2907 return 0;
2908 }
2909
2910 static struct ftrace_func_command ftrace_mod_cmd = {
2911 .name = "mod",
2912 .func = ftrace_mod_callback,
2913 };
2914
ftrace_mod_cmd_init(void)2915 static int __init ftrace_mod_cmd_init(void)
2916 {
2917 return register_ftrace_command(&ftrace_mod_cmd);
2918 }
2919 device_initcall(ftrace_mod_cmd_init);
2920
2921 static void
function_trace_probe_call(unsigned long ip,unsigned long parent_ip)2922 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2923 {
2924 struct ftrace_func_probe *entry;
2925 struct hlist_head *hhd;
2926 struct hlist_node *n;
2927 unsigned long key;
2928
2929 key = hash_long(ip, FTRACE_HASH_BITS);
2930
2931 hhd = &ftrace_func_hash[key];
2932
2933 if (hlist_empty(hhd))
2934 return;
2935
2936 /*
2937 * Disable preemption for these calls to prevent a RCU grace
2938 * period. This syncs the hash iteration and freeing of items
2939 * on the hash. rcu_read_lock is too dangerous here.
2940 */
2941 preempt_disable_notrace();
2942 hlist_for_each_entry_rcu(entry, n, hhd, node) {
2943 if (entry->ip == ip)
2944 entry->ops->func(ip, parent_ip, &entry->data);
2945 }
2946 preempt_enable_notrace();
2947 }
2948
2949 static struct ftrace_ops trace_probe_ops __read_mostly =
2950 {
2951 .func = function_trace_probe_call,
2952 };
2953
2954 static int ftrace_probe_registered;
2955
__enable_ftrace_function_probe(void)2956 static void __enable_ftrace_function_probe(void)
2957 {
2958 int ret;
2959 int i;
2960
2961 if (ftrace_probe_registered)
2962 return;
2963
2964 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2965 struct hlist_head *hhd = &ftrace_func_hash[i];
2966 if (hhd->first)
2967 break;
2968 }
2969 /* Nothing registered? */
2970 if (i == FTRACE_FUNC_HASHSIZE)
2971 return;
2972
2973 ret = ftrace_startup(&trace_probe_ops, 0);
2974
2975 ftrace_probe_registered = 1;
2976 }
2977
__disable_ftrace_function_probe(void)2978 static void __disable_ftrace_function_probe(void)
2979 {
2980 int i;
2981
2982 if (!ftrace_probe_registered)
2983 return;
2984
2985 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2986 struct hlist_head *hhd = &ftrace_func_hash[i];
2987 if (hhd->first)
2988 return;
2989 }
2990
2991 /* no more funcs left */
2992 ftrace_shutdown(&trace_probe_ops, 0);
2993
2994 ftrace_probe_registered = 0;
2995 }
2996
2997
ftrace_free_entry_rcu(struct rcu_head * rhp)2998 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2999 {
3000 struct ftrace_func_probe *entry =
3001 container_of(rhp, struct ftrace_func_probe, rcu);
3002
3003 if (entry->ops->free)
3004 entry->ops->free(&entry->data);
3005 kfree(entry);
3006 }
3007
3008
3009 int
register_ftrace_function_probe(char * glob,struct ftrace_probe_ops * ops,void * data)3010 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3011 void *data)
3012 {
3013 struct ftrace_func_probe *entry;
3014 struct ftrace_page *pg;
3015 struct dyn_ftrace *rec;
3016 int type, len, not;
3017 unsigned long key;
3018 int count = 0;
3019 char *search;
3020
3021 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3022 len = strlen(search);
3023
3024 /* we do not support '!' for function probes */
3025 if (WARN_ON(not))
3026 return -EINVAL;
3027
3028 mutex_lock(&ftrace_lock);
3029
3030 if (unlikely(ftrace_disabled))
3031 goto out_unlock;
3032
3033 do_for_each_ftrace_rec(pg, rec) {
3034
3035 if (!ftrace_match_record(rec, NULL, search, len, type))
3036 continue;
3037
3038 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3039 if (!entry) {
3040 /* If we did not process any, then return error */
3041 if (!count)
3042 count = -ENOMEM;
3043 goto out_unlock;
3044 }
3045
3046 count++;
3047
3048 entry->data = data;
3049
3050 /*
3051 * The caller might want to do something special
3052 * for each function we find. We call the callback
3053 * to give the caller an opportunity to do so.
3054 */
3055 if (ops->callback) {
3056 if (ops->callback(rec->ip, &entry->data) < 0) {
3057 /* caller does not like this func */
3058 kfree(entry);
3059 continue;
3060 }
3061 }
3062
3063 entry->ops = ops;
3064 entry->ip = rec->ip;
3065
3066 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3067 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3068
3069 } while_for_each_ftrace_rec();
3070 __enable_ftrace_function_probe();
3071
3072 out_unlock:
3073 mutex_unlock(&ftrace_lock);
3074
3075 return count;
3076 }
3077
3078 enum {
3079 PROBE_TEST_FUNC = 1,
3080 PROBE_TEST_DATA = 2
3081 };
3082
3083 static void
__unregister_ftrace_function_probe(char * glob,struct ftrace_probe_ops * ops,void * data,int flags)3084 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3085 void *data, int flags)
3086 {
3087 struct ftrace_func_probe *entry;
3088 struct hlist_node *n, *tmp;
3089 char str[KSYM_SYMBOL_LEN];
3090 int type = MATCH_FULL;
3091 int i, len = 0;
3092 char *search;
3093
3094 if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3095 glob = NULL;
3096 else if (glob) {
3097 int not;
3098
3099 type = filter_parse_regex(glob, strlen(glob), &search, ¬);
3100 len = strlen(search);
3101
3102 /* we do not support '!' for function probes */
3103 if (WARN_ON(not))
3104 return;
3105 }
3106
3107 mutex_lock(&ftrace_lock);
3108 for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3109 struct hlist_head *hhd = &ftrace_func_hash[i];
3110
3111 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
3112
3113 /* break up if statements for readability */
3114 if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3115 continue;
3116
3117 if ((flags & PROBE_TEST_DATA) && entry->data != data)
3118 continue;
3119
3120 /* do this last, since it is the most expensive */
3121 if (glob) {
3122 kallsyms_lookup(entry->ip, NULL, NULL,
3123 NULL, str);
3124 if (!ftrace_match(str, glob, len, type))
3125 continue;
3126 }
3127
3128 hlist_del_rcu(&entry->node);
3129 call_rcu_sched(&entry->rcu, ftrace_free_entry_rcu);
3130 }
3131 }
3132 __disable_ftrace_function_probe();
3133 mutex_unlock(&ftrace_lock);
3134 }
3135
3136 void
unregister_ftrace_function_probe(char * glob,struct ftrace_probe_ops * ops,void * data)3137 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3138 void *data)
3139 {
3140 __unregister_ftrace_function_probe(glob, ops, data,
3141 PROBE_TEST_FUNC | PROBE_TEST_DATA);
3142 }
3143
3144 void
unregister_ftrace_function_probe_func(char * glob,struct ftrace_probe_ops * ops)3145 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3146 {
3147 __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3148 }
3149
unregister_ftrace_function_probe_all(char * glob)3150 void unregister_ftrace_function_probe_all(char *glob)
3151 {
3152 __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3153 }
3154
3155 static LIST_HEAD(ftrace_commands);
3156 static DEFINE_MUTEX(ftrace_cmd_mutex);
3157
register_ftrace_command(struct ftrace_func_command * cmd)3158 int register_ftrace_command(struct ftrace_func_command *cmd)
3159 {
3160 struct ftrace_func_command *p;
3161 int ret = 0;
3162
3163 mutex_lock(&ftrace_cmd_mutex);
3164 list_for_each_entry(p, &ftrace_commands, list) {
3165 if (strcmp(cmd->name, p->name) == 0) {
3166 ret = -EBUSY;
3167 goto out_unlock;
3168 }
3169 }
3170 list_add(&cmd->list, &ftrace_commands);
3171 out_unlock:
3172 mutex_unlock(&ftrace_cmd_mutex);
3173
3174 return ret;
3175 }
3176
unregister_ftrace_command(struct ftrace_func_command * cmd)3177 int unregister_ftrace_command(struct ftrace_func_command *cmd)
3178 {
3179 struct ftrace_func_command *p, *n;
3180 int ret = -ENODEV;
3181
3182 mutex_lock(&ftrace_cmd_mutex);
3183 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3184 if (strcmp(cmd->name, p->name) == 0) {
3185 ret = 0;
3186 list_del_init(&p->list);
3187 goto out_unlock;
3188 }
3189 }
3190 out_unlock:
3191 mutex_unlock(&ftrace_cmd_mutex);
3192
3193 return ret;
3194 }
3195
ftrace_process_regex(struct ftrace_hash * hash,char * buff,int len,int enable)3196 static int ftrace_process_regex(struct ftrace_hash *hash,
3197 char *buff, int len, int enable)
3198 {
3199 char *func, *command, *next = buff;
3200 struct ftrace_func_command *p;
3201 int ret = -EINVAL;
3202
3203 func = strsep(&next, ":");
3204
3205 if (!next) {
3206 ret = ftrace_match_records(hash, func, len);
3207 if (!ret)
3208 ret = -EINVAL;
3209 if (ret < 0)
3210 return ret;
3211 return 0;
3212 }
3213
3214 /* command found */
3215
3216 command = strsep(&next, ":");
3217
3218 mutex_lock(&ftrace_cmd_mutex);
3219 list_for_each_entry(p, &ftrace_commands, list) {
3220 if (strcmp(p->name, command) == 0) {
3221 ret = p->func(hash, func, command, next, enable);
3222 goto out_unlock;
3223 }
3224 }
3225 out_unlock:
3226 mutex_unlock(&ftrace_cmd_mutex);
3227
3228 return ret;
3229 }
3230
3231 static ssize_t
ftrace_regex_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos,int enable)3232 ftrace_regex_write(struct file *file, const char __user *ubuf,
3233 size_t cnt, loff_t *ppos, int enable)
3234 {
3235 struct ftrace_iterator *iter;
3236 struct trace_parser *parser;
3237 ssize_t ret, read;
3238
3239 if (!cnt)
3240 return 0;
3241
3242 mutex_lock(&ftrace_regex_lock);
3243
3244 ret = -ENODEV;
3245 if (unlikely(ftrace_disabled))
3246 goto out_unlock;
3247
3248 if (file->f_mode & FMODE_READ) {
3249 struct seq_file *m = file->private_data;
3250 iter = m->private;
3251 } else
3252 iter = file->private_data;
3253
3254 parser = &iter->parser;
3255 read = trace_get_user(parser, ubuf, cnt, ppos);
3256
3257 if (read >= 0 && trace_parser_loaded(parser) &&
3258 !trace_parser_cont(parser)) {
3259 ret = ftrace_process_regex(iter->hash, parser->buffer,
3260 parser->idx, enable);
3261 trace_parser_clear(parser);
3262 if (ret)
3263 goto out_unlock;
3264 }
3265
3266 ret = read;
3267 out_unlock:
3268 mutex_unlock(&ftrace_regex_lock);
3269
3270 return ret;
3271 }
3272
3273 ssize_t
ftrace_filter_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)3274 ftrace_filter_write(struct file *file, const char __user *ubuf,
3275 size_t cnt, loff_t *ppos)
3276 {
3277 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3278 }
3279
3280 ssize_t
ftrace_notrace_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)3281 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3282 size_t cnt, loff_t *ppos)
3283 {
3284 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3285 }
3286
3287 static int
ftrace_set_regex(struct ftrace_ops * ops,unsigned char * buf,int len,int reset,int enable)3288 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3289 int reset, int enable)
3290 {
3291 struct ftrace_hash **orig_hash;
3292 struct ftrace_hash *hash;
3293 int ret;
3294
3295 /* All global ops uses the global ops filters */
3296 if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3297 ops = &global_ops;
3298
3299 if (unlikely(ftrace_disabled))
3300 return -ENODEV;
3301
3302 if (enable)
3303 orig_hash = &ops->filter_hash;
3304 else
3305 orig_hash = &ops->notrace_hash;
3306
3307 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3308 if (!hash)
3309 return -ENOMEM;
3310
3311 mutex_lock(&ftrace_regex_lock);
3312 if (reset)
3313 ftrace_filter_reset(hash);
3314 if (buf && !ftrace_match_records(hash, buf, len)) {
3315 ret = -EINVAL;
3316 goto out_regex_unlock;
3317 }
3318
3319 mutex_lock(&ftrace_lock);
3320 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3321 if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3322 && ftrace_enabled)
3323 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3324
3325 mutex_unlock(&ftrace_lock);
3326
3327 out_regex_unlock:
3328 mutex_unlock(&ftrace_regex_lock);
3329
3330 free_ftrace_hash(hash);
3331 return ret;
3332 }
3333
3334 /**
3335 * ftrace_set_filter - set a function to filter on in ftrace
3336 * @ops - the ops to set the filter with
3337 * @buf - the string that holds the function filter text.
3338 * @len - the length of the string.
3339 * @reset - non zero to reset all filters before applying this filter.
3340 *
3341 * Filters denote which functions should be enabled when tracing is enabled.
3342 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3343 */
ftrace_set_filter(struct ftrace_ops * ops,unsigned char * buf,int len,int reset)3344 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3345 int len, int reset)
3346 {
3347 return ftrace_set_regex(ops, buf, len, reset, 1);
3348 }
3349 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3350
3351 /**
3352 * ftrace_set_notrace - set a function to not trace in ftrace
3353 * @ops - the ops to set the notrace filter with
3354 * @buf - the string that holds the function notrace text.
3355 * @len - the length of the string.
3356 * @reset - non zero to reset all filters before applying this filter.
3357 *
3358 * Notrace Filters denote which functions should not be enabled when tracing
3359 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3360 * for tracing.
3361 */
ftrace_set_notrace(struct ftrace_ops * ops,unsigned char * buf,int len,int reset)3362 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3363 int len, int reset)
3364 {
3365 return ftrace_set_regex(ops, buf, len, reset, 0);
3366 }
3367 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3368 /**
3369 * ftrace_set_filter - set a function to filter on in ftrace
3370 * @ops - the ops to set the filter with
3371 * @buf - the string that holds the function filter text.
3372 * @len - the length of the string.
3373 * @reset - non zero to reset all filters before applying this filter.
3374 *
3375 * Filters denote which functions should be enabled when tracing is enabled.
3376 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3377 */
ftrace_set_global_filter(unsigned char * buf,int len,int reset)3378 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3379 {
3380 ftrace_set_regex(&global_ops, buf, len, reset, 1);
3381 }
3382 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3383
3384 /**
3385 * ftrace_set_notrace - set a function to not trace in ftrace
3386 * @ops - the ops to set the notrace filter with
3387 * @buf - the string that holds the function notrace text.
3388 * @len - the length of the string.
3389 * @reset - non zero to reset all filters before applying this filter.
3390 *
3391 * Notrace Filters denote which functions should not be enabled when tracing
3392 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3393 * for tracing.
3394 */
ftrace_set_global_notrace(unsigned char * buf,int len,int reset)3395 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3396 {
3397 ftrace_set_regex(&global_ops, buf, len, reset, 0);
3398 }
3399 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3400
3401 /*
3402 * command line interface to allow users to set filters on boot up.
3403 */
3404 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
3405 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3406 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3407
set_ftrace_notrace(char * str)3408 static int __init set_ftrace_notrace(char *str)
3409 {
3410 strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3411 return 1;
3412 }
3413 __setup("ftrace_notrace=", set_ftrace_notrace);
3414
set_ftrace_filter(char * str)3415 static int __init set_ftrace_filter(char *str)
3416 {
3417 strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3418 return 1;
3419 }
3420 __setup("ftrace_filter=", set_ftrace_filter);
3421
3422 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3423 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3424 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3425
set_graph_function(char * str)3426 static int __init set_graph_function(char *str)
3427 {
3428 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3429 return 1;
3430 }
3431 __setup("ftrace_graph_filter=", set_graph_function);
3432
set_ftrace_early_graph(char * buf)3433 static void __init set_ftrace_early_graph(char *buf)
3434 {
3435 int ret;
3436 char *func;
3437
3438 while (buf) {
3439 func = strsep(&buf, ",");
3440 /* we allow only one expression at a time */
3441 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3442 func);
3443 if (ret)
3444 printk(KERN_DEBUG "ftrace: function %s not "
3445 "traceable\n", func);
3446 }
3447 }
3448 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3449
3450 void __init
ftrace_set_early_filter(struct ftrace_ops * ops,char * buf,int enable)3451 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3452 {
3453 char *func;
3454
3455 while (buf) {
3456 func = strsep(&buf, ",");
3457 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3458 }
3459 }
3460
set_ftrace_early_filters(void)3461 static void __init set_ftrace_early_filters(void)
3462 {
3463 if (ftrace_filter_buf[0])
3464 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3465 if (ftrace_notrace_buf[0])
3466 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3467 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3468 if (ftrace_graph_buf[0])
3469 set_ftrace_early_graph(ftrace_graph_buf);
3470 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3471 }
3472
ftrace_regex_release(struct inode * inode,struct file * file)3473 int ftrace_regex_release(struct inode *inode, struct file *file)
3474 {
3475 struct seq_file *m = (struct seq_file *)file->private_data;
3476 struct ftrace_iterator *iter;
3477 struct ftrace_hash **orig_hash;
3478 struct trace_parser *parser;
3479 int filter_hash;
3480 int ret;
3481
3482 mutex_lock(&ftrace_regex_lock);
3483 if (file->f_mode & FMODE_READ) {
3484 iter = m->private;
3485
3486 seq_release(inode, file);
3487 } else
3488 iter = file->private_data;
3489
3490 parser = &iter->parser;
3491 if (trace_parser_loaded(parser)) {
3492 parser->buffer[parser->idx] = 0;
3493 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3494 }
3495
3496 trace_parser_put(parser);
3497
3498 if (file->f_mode & FMODE_WRITE) {
3499 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3500
3501 if (filter_hash)
3502 orig_hash = &iter->ops->filter_hash;
3503 else
3504 orig_hash = &iter->ops->notrace_hash;
3505
3506 mutex_lock(&ftrace_lock);
3507 ret = ftrace_hash_move(iter->ops, filter_hash,
3508 orig_hash, iter->hash);
3509 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3510 && ftrace_enabled)
3511 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3512
3513 mutex_unlock(&ftrace_lock);
3514 }
3515 free_ftrace_hash(iter->hash);
3516 kfree(iter);
3517
3518 mutex_unlock(&ftrace_regex_lock);
3519 return 0;
3520 }
3521
3522 static const struct file_operations ftrace_avail_fops = {
3523 .open = ftrace_avail_open,
3524 .read = seq_read,
3525 .llseek = seq_lseek,
3526 .release = seq_release_private,
3527 };
3528
3529 static const struct file_operations ftrace_enabled_fops = {
3530 .open = ftrace_enabled_open,
3531 .read = seq_read,
3532 .llseek = seq_lseek,
3533 .release = seq_release_private,
3534 };
3535
3536 static const struct file_operations ftrace_filter_fops = {
3537 .open = ftrace_filter_open,
3538 .read = seq_read,
3539 .write = ftrace_filter_write,
3540 .llseek = ftrace_filter_lseek,
3541 .release = ftrace_regex_release,
3542 };
3543
3544 static const struct file_operations ftrace_notrace_fops = {
3545 .open = ftrace_notrace_open,
3546 .read = seq_read,
3547 .write = ftrace_notrace_write,
3548 .llseek = ftrace_filter_lseek,
3549 .release = ftrace_regex_release,
3550 };
3551
3552 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3553
3554 static DEFINE_MUTEX(graph_lock);
3555
3556 int ftrace_graph_count;
3557 int ftrace_graph_filter_enabled;
3558 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3559
3560 static void *
__g_next(struct seq_file * m,loff_t * pos)3561 __g_next(struct seq_file *m, loff_t *pos)
3562 {
3563 if (*pos >= ftrace_graph_count)
3564 return NULL;
3565 return &ftrace_graph_funcs[*pos];
3566 }
3567
3568 static void *
g_next(struct seq_file * m,void * v,loff_t * pos)3569 g_next(struct seq_file *m, void *v, loff_t *pos)
3570 {
3571 (*pos)++;
3572 return __g_next(m, pos);
3573 }
3574
g_start(struct seq_file * m,loff_t * pos)3575 static void *g_start(struct seq_file *m, loff_t *pos)
3576 {
3577 mutex_lock(&graph_lock);
3578
3579 /* Nothing, tell g_show to print all functions are enabled */
3580 if (!ftrace_graph_filter_enabled && !*pos)
3581 return (void *)1;
3582
3583 return __g_next(m, pos);
3584 }
3585
g_stop(struct seq_file * m,void * p)3586 static void g_stop(struct seq_file *m, void *p)
3587 {
3588 mutex_unlock(&graph_lock);
3589 }
3590
g_show(struct seq_file * m,void * v)3591 static int g_show(struct seq_file *m, void *v)
3592 {
3593 unsigned long *ptr = v;
3594
3595 if (!ptr)
3596 return 0;
3597
3598 if (ptr == (unsigned long *)1) {
3599 seq_printf(m, "#### all functions enabled ####\n");
3600 return 0;
3601 }
3602
3603 seq_printf(m, "%ps\n", (void *)*ptr);
3604
3605 return 0;
3606 }
3607
3608 static const struct seq_operations ftrace_graph_seq_ops = {
3609 .start = g_start,
3610 .next = g_next,
3611 .stop = g_stop,
3612 .show = g_show,
3613 };
3614
3615 static int
ftrace_graph_open(struct inode * inode,struct file * file)3616 ftrace_graph_open(struct inode *inode, struct file *file)
3617 {
3618 int ret = 0;
3619
3620 if (unlikely(ftrace_disabled))
3621 return -ENODEV;
3622
3623 mutex_lock(&graph_lock);
3624 if ((file->f_mode & FMODE_WRITE) &&
3625 (file->f_flags & O_TRUNC)) {
3626 ftrace_graph_filter_enabled = 0;
3627 ftrace_graph_count = 0;
3628 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3629 }
3630 mutex_unlock(&graph_lock);
3631
3632 if (file->f_mode & FMODE_READ)
3633 ret = seq_open(file, &ftrace_graph_seq_ops);
3634
3635 return ret;
3636 }
3637
3638 static int
ftrace_graph_release(struct inode * inode,struct file * file)3639 ftrace_graph_release(struct inode *inode, struct file *file)
3640 {
3641 if (file->f_mode & FMODE_READ)
3642 seq_release(inode, file);
3643 return 0;
3644 }
3645
3646 static int
ftrace_set_func(unsigned long * array,int * idx,char * buffer)3647 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3648 {
3649 struct dyn_ftrace *rec;
3650 struct ftrace_page *pg;
3651 int search_len;
3652 int fail = 1;
3653 int type, not;
3654 char *search;
3655 bool exists;
3656 int i;
3657
3658 /* decode regex */
3659 type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
3660 if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3661 return -EBUSY;
3662
3663 search_len = strlen(search);
3664
3665 mutex_lock(&ftrace_lock);
3666
3667 if (unlikely(ftrace_disabled)) {
3668 mutex_unlock(&ftrace_lock);
3669 return -ENODEV;
3670 }
3671
3672 do_for_each_ftrace_rec(pg, rec) {
3673
3674 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3675 /* if it is in the array */
3676 exists = false;
3677 for (i = 0; i < *idx; i++) {
3678 if (array[i] == rec->ip) {
3679 exists = true;
3680 break;
3681 }
3682 }
3683
3684 if (!not) {
3685 fail = 0;
3686 if (!exists) {
3687 array[(*idx)++] = rec->ip;
3688 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3689 goto out;
3690 }
3691 } else {
3692 if (exists) {
3693 array[i] = array[--(*idx)];
3694 array[*idx] = 0;
3695 fail = 0;
3696 }
3697 }
3698 }
3699 } while_for_each_ftrace_rec();
3700 out:
3701 mutex_unlock(&ftrace_lock);
3702
3703 if (fail)
3704 return -EINVAL;
3705
3706 ftrace_graph_filter_enabled = !!(*idx);
3707
3708 return 0;
3709 }
3710
3711 static ssize_t
ftrace_graph_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)3712 ftrace_graph_write(struct file *file, const char __user *ubuf,
3713 size_t cnt, loff_t *ppos)
3714 {
3715 struct trace_parser parser;
3716 ssize_t read, ret;
3717
3718 if (!cnt)
3719 return 0;
3720
3721 mutex_lock(&graph_lock);
3722
3723 if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3724 ret = -ENOMEM;
3725 goto out_unlock;
3726 }
3727
3728 read = trace_get_user(&parser, ubuf, cnt, ppos);
3729
3730 if (read >= 0 && trace_parser_loaded((&parser))) {
3731 parser.buffer[parser.idx] = 0;
3732
3733 /* we allow only one expression at a time */
3734 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3735 parser.buffer);
3736 if (ret)
3737 goto out_free;
3738 }
3739
3740 ret = read;
3741
3742 out_free:
3743 trace_parser_put(&parser);
3744 out_unlock:
3745 mutex_unlock(&graph_lock);
3746
3747 return ret;
3748 }
3749
3750 static const struct file_operations ftrace_graph_fops = {
3751 .open = ftrace_graph_open,
3752 .read = seq_read,
3753 .write = ftrace_graph_write,
3754 .llseek = ftrace_filter_lseek,
3755 .release = ftrace_graph_release,
3756 };
3757 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3758
ftrace_init_dyn_debugfs(struct dentry * d_tracer)3759 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3760 {
3761
3762 trace_create_file("available_filter_functions", 0444,
3763 d_tracer, NULL, &ftrace_avail_fops);
3764
3765 trace_create_file("enabled_functions", 0444,
3766 d_tracer, NULL, &ftrace_enabled_fops);
3767
3768 trace_create_file("set_ftrace_filter", 0644, d_tracer,
3769 NULL, &ftrace_filter_fops);
3770
3771 trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3772 NULL, &ftrace_notrace_fops);
3773
3774 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3775 trace_create_file("set_graph_function", 0444, d_tracer,
3776 NULL,
3777 &ftrace_graph_fops);
3778 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3779
3780 return 0;
3781 }
3782
ftrace_swap_recs(void * a,void * b,int size)3783 static void ftrace_swap_recs(void *a, void *b, int size)
3784 {
3785 struct dyn_ftrace *reca = a;
3786 struct dyn_ftrace *recb = b;
3787 struct dyn_ftrace t;
3788
3789 t = *reca;
3790 *reca = *recb;
3791 *recb = t;
3792 }
3793
ftrace_process_locs(struct module * mod,unsigned long * start,unsigned long * end)3794 static int ftrace_process_locs(struct module *mod,
3795 unsigned long *start,
3796 unsigned long *end)
3797 {
3798 struct ftrace_page *pg;
3799 unsigned long count;
3800 unsigned long *p;
3801 unsigned long addr;
3802 unsigned long flags = 0; /* Shut up gcc */
3803 int ret = -ENOMEM;
3804
3805 count = end - start;
3806
3807 if (!count)
3808 return 0;
3809
3810 pg = ftrace_allocate_pages(count);
3811 if (!pg)
3812 return -ENOMEM;
3813
3814 mutex_lock(&ftrace_lock);
3815
3816 /*
3817 * Core and each module needs their own pages, as
3818 * modules will free them when they are removed.
3819 * Force a new page to be allocated for modules.
3820 */
3821 if (!mod) {
3822 WARN_ON(ftrace_pages || ftrace_pages_start);
3823 /* First initialization */
3824 ftrace_pages = ftrace_pages_start = pg;
3825 } else {
3826 if (!ftrace_pages)
3827 goto out;
3828
3829 if (WARN_ON(ftrace_pages->next)) {
3830 /* Hmm, we have free pages? */
3831 while (ftrace_pages->next)
3832 ftrace_pages = ftrace_pages->next;
3833 }
3834
3835 ftrace_pages->next = pg;
3836 ftrace_pages = pg;
3837 }
3838
3839 p = start;
3840 while (p < end) {
3841 addr = ftrace_call_adjust(*p++);
3842 /*
3843 * Some architecture linkers will pad between
3844 * the different mcount_loc sections of different
3845 * object files to satisfy alignments.
3846 * Skip any NULL pointers.
3847 */
3848 if (!addr)
3849 continue;
3850 if (!ftrace_record_ip(addr))
3851 break;
3852 }
3853
3854 /* These new locations need to be initialized */
3855 ftrace_new_pgs = pg;
3856
3857 /* Make each individual set of pages sorted by ips */
3858 for (; pg; pg = pg->next)
3859 sort(pg->records, pg->index, sizeof(struct dyn_ftrace),
3860 ftrace_cmp_recs, ftrace_swap_recs);
3861
3862 /*
3863 * We only need to disable interrupts on start up
3864 * because we are modifying code that an interrupt
3865 * may execute, and the modification is not atomic.
3866 * But for modules, nothing runs the code we modify
3867 * until we are finished with it, and there's no
3868 * reason to cause large interrupt latencies while we do it.
3869 */
3870 if (!mod)
3871 local_irq_save(flags);
3872 ftrace_update_code(mod);
3873 if (!mod)
3874 local_irq_restore(flags);
3875 ret = 0;
3876 out:
3877 mutex_unlock(&ftrace_lock);
3878
3879 return ret;
3880 }
3881
3882 #ifdef CONFIG_MODULES
3883
3884 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3885
ftrace_release_mod(struct module * mod)3886 void ftrace_release_mod(struct module *mod)
3887 {
3888 struct dyn_ftrace *rec;
3889 struct ftrace_page **last_pg;
3890 struct ftrace_page *pg;
3891 int order;
3892
3893 mutex_lock(&ftrace_lock);
3894
3895 if (ftrace_disabled)
3896 goto out_unlock;
3897
3898 /*
3899 * Each module has its own ftrace_pages, remove
3900 * them from the list.
3901 */
3902 last_pg = &ftrace_pages_start;
3903 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
3904 rec = &pg->records[0];
3905 if (within_module_core(rec->ip, mod)) {
3906 /*
3907 * As core pages are first, the first
3908 * page should never be a module page.
3909 */
3910 if (WARN_ON(pg == ftrace_pages_start))
3911 goto out_unlock;
3912
3913 /* Check if we are deleting the last page */
3914 if (pg == ftrace_pages)
3915 ftrace_pages = next_to_ftrace_page(last_pg);
3916
3917 *last_pg = pg->next;
3918 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3919 free_pages((unsigned long)pg->records, order);
3920 kfree(pg);
3921 } else
3922 last_pg = &pg->next;
3923 }
3924 out_unlock:
3925 mutex_unlock(&ftrace_lock);
3926 }
3927
ftrace_init_module(struct module * mod,unsigned long * start,unsigned long * end)3928 static void ftrace_init_module(struct module *mod,
3929 unsigned long *start, unsigned long *end)
3930 {
3931 if (ftrace_disabled || start == end)
3932 return;
3933 ftrace_process_locs(mod, start, end);
3934 }
3935
ftrace_module_init(struct module * mod)3936 void ftrace_module_init(struct module *mod)
3937 {
3938 ftrace_init_module(mod, mod->ftrace_callsites,
3939 mod->ftrace_callsites +
3940 mod->num_ftrace_callsites);
3941 }
3942
ftrace_module_notify_exit(struct notifier_block * self,unsigned long val,void * data)3943 static int ftrace_module_notify_exit(struct notifier_block *self,
3944 unsigned long val, void *data)
3945 {
3946 struct module *mod = data;
3947
3948 if (val == MODULE_STATE_GOING)
3949 ftrace_release_mod(mod);
3950
3951 return 0;
3952 }
3953 #else
ftrace_module_notify_exit(struct notifier_block * self,unsigned long val,void * data)3954 static int ftrace_module_notify_exit(struct notifier_block *self,
3955 unsigned long val, void *data)
3956 {
3957 return 0;
3958 }
3959 #endif /* CONFIG_MODULES */
3960
3961 struct notifier_block ftrace_module_exit_nb = {
3962 .notifier_call = ftrace_module_notify_exit,
3963 .priority = INT_MIN, /* Run after anything that can remove kprobes */
3964 };
3965
3966 extern unsigned long __start_mcount_loc[];
3967 extern unsigned long __stop_mcount_loc[];
3968
ftrace_init(void)3969 void __init ftrace_init(void)
3970 {
3971 unsigned long count, addr, flags;
3972 int ret;
3973
3974 /* Keep the ftrace pointer to the stub */
3975 addr = (unsigned long)ftrace_stub;
3976
3977 local_irq_save(flags);
3978 ftrace_dyn_arch_init(&addr);
3979 local_irq_restore(flags);
3980
3981 /* ftrace_dyn_arch_init places the return code in addr */
3982 if (addr)
3983 goto failed;
3984
3985 count = __stop_mcount_loc - __start_mcount_loc;
3986
3987 ret = ftrace_dyn_table_alloc(count);
3988 if (ret)
3989 goto failed;
3990
3991 last_ftrace_enabled = ftrace_enabled = 1;
3992
3993 ret = ftrace_process_locs(NULL,
3994 __start_mcount_loc,
3995 __stop_mcount_loc);
3996
3997 ret = register_module_notifier(&ftrace_module_exit_nb);
3998 if (ret)
3999 pr_warning("Failed to register trace ftrace module exit notifier\n");
4000
4001 set_ftrace_early_filters();
4002
4003 return;
4004 failed:
4005 ftrace_disabled = 1;
4006 }
4007
4008 #else
4009
4010 static struct ftrace_ops global_ops = {
4011 .func = ftrace_stub,
4012 };
4013
ftrace_nodyn_init(void)4014 static int __init ftrace_nodyn_init(void)
4015 {
4016 ftrace_enabled = 1;
4017 return 0;
4018 }
4019 device_initcall(ftrace_nodyn_init);
4020
ftrace_init_dyn_debugfs(struct dentry * d_tracer)4021 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
ftrace_startup_enable(int command)4022 static inline void ftrace_startup_enable(int command) { }
4023 /* Keep as macros so we do not need to define the commands */
4024 # define ftrace_startup(ops, command) \
4025 ({ \
4026 int ___ret = __register_ftrace_function(ops); \
4027 if (!___ret) \
4028 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
4029 ___ret; \
4030 })
4031 # define ftrace_shutdown(ops, command) __unregister_ftrace_function(ops)
4032
4033 # define ftrace_startup_sysctl() do { } while (0)
4034 # define ftrace_shutdown_sysctl() do { } while (0)
4035
4036 static inline int
ftrace_ops_test(struct ftrace_ops * ops,unsigned long ip)4037 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
4038 {
4039 return 1;
4040 }
4041
4042 #endif /* CONFIG_DYNAMIC_FTRACE */
4043
4044 static void
ftrace_ops_control_func(unsigned long ip,unsigned long parent_ip)4045 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip)
4046 {
4047 struct ftrace_ops *op;
4048
4049 if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4050 return;
4051
4052 /*
4053 * Some of the ops may be dynamically allocated,
4054 * they must be freed after a synchronize_sched().
4055 */
4056 preempt_disable_notrace();
4057 trace_recursion_set(TRACE_CONTROL_BIT);
4058 op = rcu_dereference_raw(ftrace_control_list);
4059 while (op != &ftrace_list_end) {
4060 if (!ftrace_function_local_disabled(op) &&
4061 ftrace_ops_test(op, ip))
4062 op->func(ip, parent_ip);
4063
4064 op = rcu_dereference_raw(op->next);
4065 };
4066 trace_recursion_clear(TRACE_CONTROL_BIT);
4067 preempt_enable_notrace();
4068 }
4069
4070 static struct ftrace_ops control_ops = {
4071 .func = ftrace_ops_control_func,
4072 };
4073
4074 static void
ftrace_ops_list_func(unsigned long ip,unsigned long parent_ip)4075 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
4076 {
4077 struct ftrace_ops *op;
4078
4079 if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
4080 return;
4081
4082 trace_recursion_set(TRACE_INTERNAL_BIT);
4083 /*
4084 * Some of the ops may be dynamically allocated,
4085 * they must be freed after a synchronize_sched().
4086 */
4087 preempt_disable_notrace();
4088 op = rcu_dereference_raw(ftrace_ops_list);
4089 while (op != &ftrace_list_end) {
4090 if (ftrace_ops_test(op, ip))
4091 op->func(ip, parent_ip);
4092 op = rcu_dereference_raw(op->next);
4093 };
4094 preempt_enable_notrace();
4095 trace_recursion_clear(TRACE_INTERNAL_BIT);
4096 }
4097
clear_ftrace_swapper(void)4098 static void clear_ftrace_swapper(void)
4099 {
4100 struct task_struct *p;
4101 int cpu;
4102
4103 get_online_cpus();
4104 for_each_online_cpu(cpu) {
4105 p = idle_task(cpu);
4106 clear_tsk_trace_trace(p);
4107 }
4108 put_online_cpus();
4109 }
4110
set_ftrace_swapper(void)4111 static void set_ftrace_swapper(void)
4112 {
4113 struct task_struct *p;
4114 int cpu;
4115
4116 get_online_cpus();
4117 for_each_online_cpu(cpu) {
4118 p = idle_task(cpu);
4119 set_tsk_trace_trace(p);
4120 }
4121 put_online_cpus();
4122 }
4123
clear_ftrace_pid(struct pid * pid)4124 static void clear_ftrace_pid(struct pid *pid)
4125 {
4126 struct task_struct *p;
4127
4128 rcu_read_lock();
4129 do_each_pid_task(pid, PIDTYPE_PID, p) {
4130 clear_tsk_trace_trace(p);
4131 } while_each_pid_task(pid, PIDTYPE_PID, p);
4132 rcu_read_unlock();
4133
4134 put_pid(pid);
4135 }
4136
set_ftrace_pid(struct pid * pid)4137 static void set_ftrace_pid(struct pid *pid)
4138 {
4139 struct task_struct *p;
4140
4141 rcu_read_lock();
4142 do_each_pid_task(pid, PIDTYPE_PID, p) {
4143 set_tsk_trace_trace(p);
4144 } while_each_pid_task(pid, PIDTYPE_PID, p);
4145 rcu_read_unlock();
4146 }
4147
clear_ftrace_pid_task(struct pid * pid)4148 static void clear_ftrace_pid_task(struct pid *pid)
4149 {
4150 if (pid == ftrace_swapper_pid)
4151 clear_ftrace_swapper();
4152 else
4153 clear_ftrace_pid(pid);
4154 }
4155
set_ftrace_pid_task(struct pid * pid)4156 static void set_ftrace_pid_task(struct pid *pid)
4157 {
4158 if (pid == ftrace_swapper_pid)
4159 set_ftrace_swapper();
4160 else
4161 set_ftrace_pid(pid);
4162 }
4163
ftrace_pid_add(int p)4164 static int ftrace_pid_add(int p)
4165 {
4166 struct pid *pid;
4167 struct ftrace_pid *fpid;
4168 int ret = -EINVAL;
4169
4170 mutex_lock(&ftrace_lock);
4171
4172 if (!p)
4173 pid = ftrace_swapper_pid;
4174 else
4175 pid = find_get_pid(p);
4176
4177 if (!pid)
4178 goto out;
4179
4180 ret = 0;
4181
4182 list_for_each_entry(fpid, &ftrace_pids, list)
4183 if (fpid->pid == pid)
4184 goto out_put;
4185
4186 ret = -ENOMEM;
4187
4188 fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4189 if (!fpid)
4190 goto out_put;
4191
4192 list_add(&fpid->list, &ftrace_pids);
4193 fpid->pid = pid;
4194
4195 set_ftrace_pid_task(pid);
4196
4197 ftrace_update_pid_func();
4198 ftrace_startup_enable(0);
4199
4200 mutex_unlock(&ftrace_lock);
4201 return 0;
4202
4203 out_put:
4204 if (pid != ftrace_swapper_pid)
4205 put_pid(pid);
4206
4207 out:
4208 mutex_unlock(&ftrace_lock);
4209 return ret;
4210 }
4211
ftrace_pid_reset(void)4212 static void ftrace_pid_reset(void)
4213 {
4214 struct ftrace_pid *fpid, *safe;
4215
4216 mutex_lock(&ftrace_lock);
4217 list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4218 struct pid *pid = fpid->pid;
4219
4220 clear_ftrace_pid_task(pid);
4221
4222 list_del(&fpid->list);
4223 kfree(fpid);
4224 }
4225
4226 ftrace_update_pid_func();
4227 ftrace_startup_enable(0);
4228
4229 mutex_unlock(&ftrace_lock);
4230 }
4231
fpid_start(struct seq_file * m,loff_t * pos)4232 static void *fpid_start(struct seq_file *m, loff_t *pos)
4233 {
4234 mutex_lock(&ftrace_lock);
4235
4236 if (list_empty(&ftrace_pids) && (!*pos))
4237 return (void *) 1;
4238
4239 return seq_list_start(&ftrace_pids, *pos);
4240 }
4241
fpid_next(struct seq_file * m,void * v,loff_t * pos)4242 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4243 {
4244 if (v == (void *)1)
4245 return NULL;
4246
4247 return seq_list_next(v, &ftrace_pids, pos);
4248 }
4249
fpid_stop(struct seq_file * m,void * p)4250 static void fpid_stop(struct seq_file *m, void *p)
4251 {
4252 mutex_unlock(&ftrace_lock);
4253 }
4254
fpid_show(struct seq_file * m,void * v)4255 static int fpid_show(struct seq_file *m, void *v)
4256 {
4257 const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4258
4259 if (v == (void *)1) {
4260 seq_printf(m, "no pid\n");
4261 return 0;
4262 }
4263
4264 if (fpid->pid == ftrace_swapper_pid)
4265 seq_printf(m, "swapper tasks\n");
4266 else
4267 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4268
4269 return 0;
4270 }
4271
4272 static const struct seq_operations ftrace_pid_sops = {
4273 .start = fpid_start,
4274 .next = fpid_next,
4275 .stop = fpid_stop,
4276 .show = fpid_show,
4277 };
4278
4279 static int
ftrace_pid_open(struct inode * inode,struct file * file)4280 ftrace_pid_open(struct inode *inode, struct file *file)
4281 {
4282 int ret = 0;
4283
4284 if ((file->f_mode & FMODE_WRITE) &&
4285 (file->f_flags & O_TRUNC))
4286 ftrace_pid_reset();
4287
4288 if (file->f_mode & FMODE_READ)
4289 ret = seq_open(file, &ftrace_pid_sops);
4290
4291 return ret;
4292 }
4293
4294 static ssize_t
ftrace_pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)4295 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4296 size_t cnt, loff_t *ppos)
4297 {
4298 char buf[64], *tmp;
4299 long val;
4300 int ret;
4301
4302 if (cnt >= sizeof(buf))
4303 return -EINVAL;
4304
4305 if (copy_from_user(&buf, ubuf, cnt))
4306 return -EFAULT;
4307
4308 buf[cnt] = 0;
4309
4310 /*
4311 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4312 * to clean the filter quietly.
4313 */
4314 tmp = strstrip(buf);
4315 if (strlen(tmp) == 0)
4316 return 1;
4317
4318 ret = strict_strtol(tmp, 10, &val);
4319 if (ret < 0)
4320 return ret;
4321
4322 ret = ftrace_pid_add(val);
4323
4324 return ret ? ret : cnt;
4325 }
4326
4327 static int
ftrace_pid_release(struct inode * inode,struct file * file)4328 ftrace_pid_release(struct inode *inode, struct file *file)
4329 {
4330 if (file->f_mode & FMODE_READ)
4331 seq_release(inode, file);
4332
4333 return 0;
4334 }
4335
4336 static const struct file_operations ftrace_pid_fops = {
4337 .open = ftrace_pid_open,
4338 .write = ftrace_pid_write,
4339 .read = seq_read,
4340 .llseek = ftrace_filter_lseek,
4341 .release = ftrace_pid_release,
4342 };
4343
ftrace_init_debugfs(void)4344 static __init int ftrace_init_debugfs(void)
4345 {
4346 struct dentry *d_tracer;
4347
4348 d_tracer = tracing_init_dentry();
4349 if (!d_tracer)
4350 return 0;
4351
4352 ftrace_init_dyn_debugfs(d_tracer);
4353
4354 trace_create_file("set_ftrace_pid", 0644, d_tracer,
4355 NULL, &ftrace_pid_fops);
4356
4357 ftrace_profile_debugfs(d_tracer);
4358
4359 return 0;
4360 }
4361 fs_initcall(ftrace_init_debugfs);
4362
4363 /**
4364 * ftrace_kill - kill ftrace
4365 *
4366 * This function should be used by panic code. It stops ftrace
4367 * but in a not so nice way. If you need to simply kill ftrace
4368 * from a non-atomic section, use ftrace_kill.
4369 */
ftrace_kill(void)4370 void ftrace_kill(void)
4371 {
4372 ftrace_disabled = 1;
4373 ftrace_enabled = 0;
4374 clear_ftrace_function();
4375 }
4376
4377 /**
4378 * Test if ftrace is dead or not.
4379 */
ftrace_is_dead(void)4380 int ftrace_is_dead(void)
4381 {
4382 return ftrace_disabled;
4383 }
4384
4385 /**
4386 * register_ftrace_function - register a function for profiling
4387 * @ops - ops structure that holds the function for profiling.
4388 *
4389 * Register a function to be called by all functions in the
4390 * kernel.
4391 *
4392 * Note: @ops->func and all the functions it calls must be labeled
4393 * with "notrace", otherwise it will go into a
4394 * recursive loop.
4395 */
register_ftrace_function(struct ftrace_ops * ops)4396 int register_ftrace_function(struct ftrace_ops *ops)
4397 {
4398 int ret = -1;
4399
4400 mutex_lock(&ftrace_lock);
4401
4402 ret = ftrace_startup(ops, 0);
4403
4404 mutex_unlock(&ftrace_lock);
4405 return ret;
4406 }
4407 EXPORT_SYMBOL_GPL(register_ftrace_function);
4408
4409 /**
4410 * unregister_ftrace_function - unregister a function for profiling.
4411 * @ops - ops structure that holds the function to unregister
4412 *
4413 * Unregister a function that was added to be called by ftrace profiling.
4414 */
unregister_ftrace_function(struct ftrace_ops * ops)4415 int unregister_ftrace_function(struct ftrace_ops *ops)
4416 {
4417 int ret;
4418
4419 mutex_lock(&ftrace_lock);
4420 ret = ftrace_shutdown(ops, 0);
4421 mutex_unlock(&ftrace_lock);
4422
4423 return ret;
4424 }
4425 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4426
4427 int
ftrace_enable_sysctl(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)4428 ftrace_enable_sysctl(struct ctl_table *table, int write,
4429 void __user *buffer, size_t *lenp,
4430 loff_t *ppos)
4431 {
4432 int ret = -ENODEV;
4433
4434 mutex_lock(&ftrace_lock);
4435
4436 if (unlikely(ftrace_disabled))
4437 goto out;
4438
4439 ret = proc_dointvec(table, write, buffer, lenp, ppos);
4440
4441 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4442 goto out;
4443
4444 last_ftrace_enabled = !!ftrace_enabled;
4445
4446 if (ftrace_enabled) {
4447
4448 ftrace_startup_sysctl();
4449
4450 /* we are starting ftrace again */
4451 if (ftrace_ops_list != &ftrace_list_end)
4452 update_ftrace_function();
4453
4454 } else {
4455 /* stopping ftrace calls (just send to ftrace_stub) */
4456 ftrace_trace_function = ftrace_stub;
4457
4458 ftrace_shutdown_sysctl();
4459 }
4460
4461 out:
4462 mutex_unlock(&ftrace_lock);
4463 return ret;
4464 }
4465
4466 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4467
4468 static int ftrace_graph_active;
4469 static struct notifier_block ftrace_suspend_notifier;
4470
ftrace_graph_entry_stub(struct ftrace_graph_ent * trace)4471 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4472 {
4473 return 0;
4474 }
4475
4476 /* The callbacks that hook a function */
4477 trace_func_graph_ret_t ftrace_graph_return =
4478 (trace_func_graph_ret_t)ftrace_stub;
4479 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4480 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
4481
4482 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
alloc_retstack_tasklist(struct ftrace_ret_stack ** ret_stack_list)4483 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4484 {
4485 int i;
4486 int ret = 0;
4487 unsigned long flags;
4488 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4489 struct task_struct *g, *t;
4490
4491 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4492 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4493 * sizeof(struct ftrace_ret_stack),
4494 GFP_KERNEL);
4495 if (!ret_stack_list[i]) {
4496 start = 0;
4497 end = i;
4498 ret = -ENOMEM;
4499 goto free;
4500 }
4501 }
4502
4503 read_lock_irqsave(&tasklist_lock, flags);
4504 do_each_thread(g, t) {
4505 if (start == end) {
4506 ret = -EAGAIN;
4507 goto unlock;
4508 }
4509
4510 if (t->ret_stack == NULL) {
4511 atomic_set(&t->tracing_graph_pause, 0);
4512 atomic_set(&t->trace_overrun, 0);
4513 t->curr_ret_stack = -1;
4514 /* Make sure the tasks see the -1 first: */
4515 smp_wmb();
4516 t->ret_stack = ret_stack_list[start++];
4517 }
4518 } while_each_thread(g, t);
4519
4520 unlock:
4521 read_unlock_irqrestore(&tasklist_lock, flags);
4522 free:
4523 for (i = start; i < end; i++)
4524 kfree(ret_stack_list[i]);
4525 return ret;
4526 }
4527
4528 static void
ftrace_graph_probe_sched_switch(void * ignore,struct task_struct * prev,struct task_struct * next)4529 ftrace_graph_probe_sched_switch(void *ignore,
4530 struct task_struct *prev, struct task_struct *next)
4531 {
4532 unsigned long long timestamp;
4533 int index;
4534
4535 /*
4536 * Does the user want to count the time a function was asleep.
4537 * If so, do not update the time stamps.
4538 */
4539 if (trace_flags & TRACE_ITER_SLEEP_TIME)
4540 return;
4541
4542 timestamp = trace_clock_local();
4543
4544 prev->ftrace_timestamp = timestamp;
4545
4546 /* only process tasks that we timestamped */
4547 if (!next->ftrace_timestamp)
4548 return;
4549
4550 /*
4551 * Update all the counters in next to make up for the
4552 * time next was sleeping.
4553 */
4554 timestamp -= next->ftrace_timestamp;
4555
4556 for (index = next->curr_ret_stack; index >= 0; index--)
4557 next->ret_stack[index].calltime += timestamp;
4558 }
4559
4560 /* Allocate a return stack for each task */
start_graph_tracing(void)4561 static int start_graph_tracing(void)
4562 {
4563 struct ftrace_ret_stack **ret_stack_list;
4564 int ret, cpu;
4565
4566 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4567 sizeof(struct ftrace_ret_stack *),
4568 GFP_KERNEL);
4569
4570 if (!ret_stack_list)
4571 return -ENOMEM;
4572
4573 /* The cpu_boot init_task->ret_stack will never be freed */
4574 for_each_online_cpu(cpu) {
4575 if (!idle_task(cpu)->ret_stack)
4576 ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4577 }
4578
4579 do {
4580 ret = alloc_retstack_tasklist(ret_stack_list);
4581 } while (ret == -EAGAIN);
4582
4583 if (!ret) {
4584 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4585 if (ret)
4586 pr_info("ftrace_graph: Couldn't activate tracepoint"
4587 " probe to kernel_sched_switch\n");
4588 }
4589
4590 kfree(ret_stack_list);
4591 return ret;
4592 }
4593
4594 /*
4595 * Hibernation protection.
4596 * The state of the current task is too much unstable during
4597 * suspend/restore to disk. We want to protect against that.
4598 */
4599 static int
ftrace_suspend_notifier_call(struct notifier_block * bl,unsigned long state,void * unused)4600 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4601 void *unused)
4602 {
4603 switch (state) {
4604 case PM_HIBERNATION_PREPARE:
4605 pause_graph_tracing();
4606 break;
4607
4608 case PM_POST_HIBERNATION:
4609 unpause_graph_tracing();
4610 break;
4611 }
4612 return NOTIFY_DONE;
4613 }
4614
4615 /* Just a place holder for function graph */
4616 static struct ftrace_ops fgraph_ops __read_mostly = {
4617 .func = ftrace_stub,
4618 .flags = FTRACE_OPS_FL_GLOBAL,
4619 };
4620
ftrace_graph_entry_test(struct ftrace_graph_ent * trace)4621 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
4622 {
4623 if (!ftrace_ops_test(&global_ops, trace->func))
4624 return 0;
4625 return __ftrace_graph_entry(trace);
4626 }
4627
4628 /*
4629 * The function graph tracer should only trace the functions defined
4630 * by set_ftrace_filter and set_ftrace_notrace. If another function
4631 * tracer ops is registered, the graph tracer requires testing the
4632 * function against the global ops, and not just trace any function
4633 * that any ftrace_ops registered.
4634 */
update_function_graph_func(void)4635 static void update_function_graph_func(void)
4636 {
4637 if (ftrace_ops_list == &ftrace_list_end ||
4638 (ftrace_ops_list == &global_ops &&
4639 global_ops.next == &ftrace_list_end))
4640 ftrace_graph_entry = __ftrace_graph_entry;
4641 else
4642 ftrace_graph_entry = ftrace_graph_entry_test;
4643 }
4644
register_ftrace_graph(trace_func_graph_ret_t retfunc,trace_func_graph_ent_t entryfunc)4645 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4646 trace_func_graph_ent_t entryfunc)
4647 {
4648 int ret = 0;
4649
4650 mutex_lock(&ftrace_lock);
4651
4652 /* we currently allow only one tracer registered at a time */
4653 if (ftrace_graph_active) {
4654 ret = -EBUSY;
4655 goto out;
4656 }
4657
4658 ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4659 register_pm_notifier(&ftrace_suspend_notifier);
4660
4661 ftrace_graph_active++;
4662 ret = start_graph_tracing();
4663 if (ret) {
4664 ftrace_graph_active--;
4665 goto out;
4666 }
4667
4668 ftrace_graph_return = retfunc;
4669
4670 /*
4671 * Update the indirect function to the entryfunc, and the
4672 * function that gets called to the entry_test first. Then
4673 * call the update fgraph entry function to determine if
4674 * the entryfunc should be called directly or not.
4675 */
4676 __ftrace_graph_entry = entryfunc;
4677 ftrace_graph_entry = ftrace_graph_entry_test;
4678 update_function_graph_func();
4679
4680 ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
4681
4682 out:
4683 mutex_unlock(&ftrace_lock);
4684 return ret;
4685 }
4686
unregister_ftrace_graph(void)4687 void unregister_ftrace_graph(void)
4688 {
4689 mutex_lock(&ftrace_lock);
4690
4691 if (unlikely(!ftrace_graph_active))
4692 goto out;
4693
4694 ftrace_graph_active--;
4695 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4696 ftrace_graph_entry = ftrace_graph_entry_stub;
4697 __ftrace_graph_entry = ftrace_graph_entry_stub;
4698 ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
4699 unregister_pm_notifier(&ftrace_suspend_notifier);
4700 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4701
4702 out:
4703 mutex_unlock(&ftrace_lock);
4704 }
4705
4706 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4707
4708 static void
graph_init_task(struct task_struct * t,struct ftrace_ret_stack * ret_stack)4709 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4710 {
4711 atomic_set(&t->tracing_graph_pause, 0);
4712 atomic_set(&t->trace_overrun, 0);
4713 t->ftrace_timestamp = 0;
4714 /* make curr_ret_stack visible before we add the ret_stack */
4715 smp_wmb();
4716 t->ret_stack = ret_stack;
4717 }
4718
4719 /*
4720 * Allocate a return stack for the idle task. May be the first
4721 * time through, or it may be done by CPU hotplug online.
4722 */
ftrace_graph_init_idle_task(struct task_struct * t,int cpu)4723 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4724 {
4725 t->curr_ret_stack = -1;
4726 /*
4727 * The idle task has no parent, it either has its own
4728 * stack or no stack at all.
4729 */
4730 if (t->ret_stack)
4731 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4732
4733 if (ftrace_graph_active) {
4734 struct ftrace_ret_stack *ret_stack;
4735
4736 ret_stack = per_cpu(idle_ret_stack, cpu);
4737 if (!ret_stack) {
4738 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4739 * sizeof(struct ftrace_ret_stack),
4740 GFP_KERNEL);
4741 if (!ret_stack)
4742 return;
4743 per_cpu(idle_ret_stack, cpu) = ret_stack;
4744 }
4745 graph_init_task(t, ret_stack);
4746 }
4747 }
4748
4749 /* Allocate a return stack for newly created task */
ftrace_graph_init_task(struct task_struct * t)4750 void ftrace_graph_init_task(struct task_struct *t)
4751 {
4752 /* Make sure we do not use the parent ret_stack */
4753 t->ret_stack = NULL;
4754 t->curr_ret_stack = -1;
4755
4756 if (ftrace_graph_active) {
4757 struct ftrace_ret_stack *ret_stack;
4758
4759 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4760 * sizeof(struct ftrace_ret_stack),
4761 GFP_KERNEL);
4762 if (!ret_stack)
4763 return;
4764 graph_init_task(t, ret_stack);
4765 }
4766 }
4767
ftrace_graph_exit_task(struct task_struct * t)4768 void ftrace_graph_exit_task(struct task_struct *t)
4769 {
4770 struct ftrace_ret_stack *ret_stack = t->ret_stack;
4771
4772 t->ret_stack = NULL;
4773 /* NULL must become visible to IRQs before we free it: */
4774 barrier();
4775
4776 kfree(ret_stack);
4777 }
4778
ftrace_graph_stop(void)4779 void ftrace_graph_stop(void)
4780 {
4781 ftrace_stop();
4782 }
4783 #endif
4784