1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * 2002-10-15  Posix Clocks & timers
4  *                           by George Anzinger george@mvista.com
5  *			     Copyright (C) 2002 2003 by MontaVista Software.
6  *
7  * 2004-06-01  Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
8  *			     Copyright (C) 2004 Boris Hu
9  *
10  * These are all the functions necessary to implement POSIX clocks & timers
11  */
12 #include <linux/mm.h>
13 #include <linux/interrupt.h>
14 #include <linux/slab.h>
15 #include <linux/time.h>
16 #include <linux/mutex.h>
17 #include <linux/sched/task.h>
18 
19 #include <linux/uaccess.h>
20 #include <linux/list.h>
21 #include <linux/init.h>
22 #include <linux/compiler.h>
23 #include <linux/hash.h>
24 #include <linux/posix-clock.h>
25 #include <linux/posix-timers.h>
26 #include <linux/syscalls.h>
27 #include <linux/wait.h>
28 #include <linux/workqueue.h>
29 #include <linux/export.h>
30 #include <linux/hashtable.h>
31 #include <linux/compat.h>
32 #include <linux/nospec.h>
33 #include <linux/time_namespace.h>
34 
35 #include "timekeeping.h"
36 #include "posix-timers.h"
37 
38 /*
39  * Management arrays for POSIX timers. Timers are now kept in static hash table
40  * with 512 entries.
41  * Timer ids are allocated by local routine, which selects proper hash head by
42  * key, constructed from current->signal address and per signal struct counter.
43  * This keeps timer ids unique per process, but now they can intersect between
44  * processes.
45  */
46 
47 /*
48  * Lets keep our timers in a slab cache :-)
49  */
50 static struct kmem_cache *posix_timers_cache;
51 
52 static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
53 static DEFINE_SPINLOCK(hash_lock);
54 
55 static const struct k_clock * const posix_clocks[];
56 static const struct k_clock *clockid_to_kclock(const clockid_t id);
57 static const struct k_clock clock_realtime, clock_monotonic;
58 
59 /*
60  * we assume that the new SIGEV_THREAD_ID shares no bits with the other
61  * SIGEV values.  Here we put out an error if this assumption fails.
62  */
63 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
64                        ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
65 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
66 #endif
67 
68 /*
69  * The timer ID is turned into a timer address by idr_find().
70  * Verifying a valid ID consists of:
71  *
72  * a) checking that idr_find() returns other than -1.
73  * b) checking that the timer id matches the one in the timer itself.
74  * c) that the timer owner is in the callers thread group.
75  */
76 
77 /*
78  * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
79  *	    to implement others.  This structure defines the various
80  *	    clocks.
81  *
82  * RESOLUTION: Clock resolution is used to round up timer and interval
83  *	    times, NOT to report clock times, which are reported with as
84  *	    much resolution as the system can muster.  In some cases this
85  *	    resolution may depend on the underlying clock hardware and
86  *	    may not be quantifiable until run time, and only then is the
87  *	    necessary code is written.	The standard says we should say
88  *	    something about this issue in the documentation...
89  *
90  * FUNCTIONS: The CLOCKs structure defines possible functions to
91  *	    handle various clock functions.
92  *
93  *	    The standard POSIX timer management code assumes the
94  *	    following: 1.) The k_itimer struct (sched.h) is used for
95  *	    the timer.  2.) The list, it_lock, it_clock, it_id and
96  *	    it_pid fields are not modified by timer code.
97  *
98  * Permissions: It is assumed that the clock_settime() function defined
99  *	    for each clock will take care of permission checks.	 Some
100  *	    clocks may be set able by any user (i.e. local process
101  *	    clocks) others not.	 Currently the only set able clock we
102  *	    have is CLOCK_REALTIME and its high res counter part, both of
103  *	    which we beg off on and pass to do_sys_settimeofday().
104  */
105 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
106 
107 #define lock_timer(tid, flags)						   \
108 ({	struct k_itimer *__timr;					   \
109 	__cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags));  \
110 	__timr;								   \
111 })
112 
hash(struct signal_struct * sig,unsigned int nr)113 static int hash(struct signal_struct *sig, unsigned int nr)
114 {
115 	return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
116 }
117 
__posix_timers_find(struct hlist_head * head,struct signal_struct * sig,timer_t id)118 static struct k_itimer *__posix_timers_find(struct hlist_head *head,
119 					    struct signal_struct *sig,
120 					    timer_t id)
121 {
122 	struct k_itimer *timer;
123 
124 	hlist_for_each_entry_rcu(timer, head, t_hash,
125 				 lockdep_is_held(&hash_lock)) {
126 		if ((timer->it_signal == sig) && (timer->it_id == id))
127 			return timer;
128 	}
129 	return NULL;
130 }
131 
posix_timer_by_id(timer_t id)132 static struct k_itimer *posix_timer_by_id(timer_t id)
133 {
134 	struct signal_struct *sig = current->signal;
135 	struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
136 
137 	return __posix_timers_find(head, sig, id);
138 }
139 
posix_timer_add(struct k_itimer * timer)140 static int posix_timer_add(struct k_itimer *timer)
141 {
142 	struct signal_struct *sig = current->signal;
143 	int first_free_id = sig->posix_timer_id;
144 	struct hlist_head *head;
145 	int ret = -ENOENT;
146 
147 	do {
148 		spin_lock(&hash_lock);
149 		head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
150 		if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
151 			hlist_add_head_rcu(&timer->t_hash, head);
152 			ret = sig->posix_timer_id;
153 		}
154 		if (++sig->posix_timer_id < 0)
155 			sig->posix_timer_id = 0;
156 		if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
157 			/* Loop over all possible ids completed */
158 			ret = -EAGAIN;
159 		spin_unlock(&hash_lock);
160 	} while (ret == -ENOENT);
161 	return ret;
162 }
163 
unlock_timer(struct k_itimer * timr,unsigned long flags)164 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
165 {
166 	spin_unlock_irqrestore(&timr->it_lock, flags);
167 }
168 
169 /* Get clock_realtime */
posix_get_realtime_timespec(clockid_t which_clock,struct timespec64 * tp)170 static int posix_get_realtime_timespec(clockid_t which_clock, struct timespec64 *tp)
171 {
172 	ktime_get_real_ts64(tp);
173 	return 0;
174 }
175 
posix_get_realtime_ktime(clockid_t which_clock)176 static ktime_t posix_get_realtime_ktime(clockid_t which_clock)
177 {
178 	return ktime_get_real();
179 }
180 
181 /* Set clock_realtime */
posix_clock_realtime_set(const clockid_t which_clock,const struct timespec64 * tp)182 static int posix_clock_realtime_set(const clockid_t which_clock,
183 				    const struct timespec64 *tp)
184 {
185 	return do_sys_settimeofday64(tp, NULL);
186 }
187 
posix_clock_realtime_adj(const clockid_t which_clock,struct __kernel_timex * t)188 static int posix_clock_realtime_adj(const clockid_t which_clock,
189 				    struct __kernel_timex *t)
190 {
191 	return do_adjtimex(t);
192 }
193 
194 /*
195  * Get monotonic time for posix timers
196  */
posix_get_monotonic_timespec(clockid_t which_clock,struct timespec64 * tp)197 static int posix_get_monotonic_timespec(clockid_t which_clock, struct timespec64 *tp)
198 {
199 	ktime_get_ts64(tp);
200 	timens_add_monotonic(tp);
201 	return 0;
202 }
203 
posix_get_monotonic_ktime(clockid_t which_clock)204 static ktime_t posix_get_monotonic_ktime(clockid_t which_clock)
205 {
206 	return ktime_get();
207 }
208 
209 /*
210  * Get monotonic-raw time for posix timers
211  */
posix_get_monotonic_raw(clockid_t which_clock,struct timespec64 * tp)212 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec64 *tp)
213 {
214 	ktime_get_raw_ts64(tp);
215 	timens_add_monotonic(tp);
216 	return 0;
217 }
218 
219 
posix_get_realtime_coarse(clockid_t which_clock,struct timespec64 * tp)220 static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec64 *tp)
221 {
222 	ktime_get_coarse_real_ts64(tp);
223 	return 0;
224 }
225 
posix_get_monotonic_coarse(clockid_t which_clock,struct timespec64 * tp)226 static int posix_get_monotonic_coarse(clockid_t which_clock,
227 						struct timespec64 *tp)
228 {
229 	ktime_get_coarse_ts64(tp);
230 	timens_add_monotonic(tp);
231 	return 0;
232 }
233 
posix_get_coarse_res(const clockid_t which_clock,struct timespec64 * tp)234 static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *tp)
235 {
236 	*tp = ktime_to_timespec64(KTIME_LOW_RES);
237 	return 0;
238 }
239 
posix_get_boottime_timespec(const clockid_t which_clock,struct timespec64 * tp)240 static int posix_get_boottime_timespec(const clockid_t which_clock, struct timespec64 *tp)
241 {
242 	ktime_get_boottime_ts64(tp);
243 	timens_add_boottime(tp);
244 	return 0;
245 }
246 
posix_get_boottime_ktime(const clockid_t which_clock)247 static ktime_t posix_get_boottime_ktime(const clockid_t which_clock)
248 {
249 	return ktime_get_boottime();
250 }
251 
posix_get_tai_timespec(clockid_t which_clock,struct timespec64 * tp)252 static int posix_get_tai_timespec(clockid_t which_clock, struct timespec64 *tp)
253 {
254 	ktime_get_clocktai_ts64(tp);
255 	return 0;
256 }
257 
posix_get_tai_ktime(clockid_t which_clock)258 static ktime_t posix_get_tai_ktime(clockid_t which_clock)
259 {
260 	return ktime_get_clocktai();
261 }
262 
posix_get_hrtimer_res(clockid_t which_clock,struct timespec64 * tp)263 static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
264 {
265 	tp->tv_sec = 0;
266 	tp->tv_nsec = hrtimer_resolution;
267 	return 0;
268 }
269 
270 /*
271  * Initialize everything, well, just everything in Posix clocks/timers ;)
272  */
init_posix_timers(void)273 static __init int init_posix_timers(void)
274 {
275 	posix_timers_cache = kmem_cache_create("posix_timers_cache",
276 					sizeof(struct k_itimer), 0,
277 					SLAB_PANIC | SLAB_ACCOUNT, NULL);
278 	return 0;
279 }
280 __initcall(init_posix_timers);
281 
282 /*
283  * The siginfo si_overrun field and the return value of timer_getoverrun(2)
284  * are of type int. Clamp the overrun value to INT_MAX
285  */
timer_overrun_to_int(struct k_itimer * timr,int baseval)286 static inline int timer_overrun_to_int(struct k_itimer *timr, int baseval)
287 {
288 	s64 sum = timr->it_overrun_last + (s64)baseval;
289 
290 	return sum > (s64)INT_MAX ? INT_MAX : (int)sum;
291 }
292 
common_hrtimer_rearm(struct k_itimer * timr)293 static void common_hrtimer_rearm(struct k_itimer *timr)
294 {
295 	struct hrtimer *timer = &timr->it.real.timer;
296 
297 	timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
298 					    timr->it_interval);
299 	hrtimer_restart(timer);
300 }
301 
302 /*
303  * This function is exported for use by the signal deliver code.  It is
304  * called just prior to the info block being released and passes that
305  * block to us.  It's function is to update the overrun entry AND to
306  * restart the timer.  It should only be called if the timer is to be
307  * restarted (i.e. we have flagged this in the sys_private entry of the
308  * info block).
309  *
310  * To protect against the timer going away while the interrupt is queued,
311  * we require that the it_requeue_pending flag be set.
312  */
posixtimer_rearm(struct kernel_siginfo * info)313 void posixtimer_rearm(struct kernel_siginfo *info)
314 {
315 	struct k_itimer *timr;
316 	unsigned long flags;
317 
318 	timr = lock_timer(info->si_tid, &flags);
319 	if (!timr)
320 		return;
321 
322 	if (timr->it_interval && timr->it_requeue_pending == info->si_sys_private) {
323 		timr->kclock->timer_rearm(timr);
324 
325 		timr->it_active = 1;
326 		timr->it_overrun_last = timr->it_overrun;
327 		timr->it_overrun = -1LL;
328 		++timr->it_requeue_pending;
329 
330 		info->si_overrun = timer_overrun_to_int(timr, info->si_overrun);
331 	}
332 
333 	unlock_timer(timr, flags);
334 }
335 
posix_timer_event(struct k_itimer * timr,int si_private)336 int posix_timer_event(struct k_itimer *timr, int si_private)
337 {
338 	enum pid_type type;
339 	int ret;
340 	/*
341 	 * FIXME: if ->sigq is queued we can race with
342 	 * dequeue_signal()->posixtimer_rearm().
343 	 *
344 	 * If dequeue_signal() sees the "right" value of
345 	 * si_sys_private it calls posixtimer_rearm().
346 	 * We re-queue ->sigq and drop ->it_lock().
347 	 * posixtimer_rearm() locks the timer
348 	 * and re-schedules it while ->sigq is pending.
349 	 * Not really bad, but not that we want.
350 	 */
351 	timr->sigq->info.si_sys_private = si_private;
352 
353 	type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID;
354 	ret = send_sigqueue(timr->sigq, timr->it_pid, type);
355 	/* If we failed to send the signal the timer stops. */
356 	return ret > 0;
357 }
358 
359 /*
360  * This function gets called when a POSIX.1b interval timer expires.  It
361  * is used as a callback from the kernel internal timer.  The
362  * run_timer_list code ALWAYS calls with interrupts on.
363 
364  * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
365  */
posix_timer_fn(struct hrtimer * timer)366 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
367 {
368 	struct k_itimer *timr;
369 	unsigned long flags;
370 	int si_private = 0;
371 	enum hrtimer_restart ret = HRTIMER_NORESTART;
372 
373 	timr = container_of(timer, struct k_itimer, it.real.timer);
374 	spin_lock_irqsave(&timr->it_lock, flags);
375 
376 	timr->it_active = 0;
377 	if (timr->it_interval != 0)
378 		si_private = ++timr->it_requeue_pending;
379 
380 	if (posix_timer_event(timr, si_private)) {
381 		/*
382 		 * signal was not sent because of sig_ignor
383 		 * we will not get a call back to restart it AND
384 		 * it should be restarted.
385 		 */
386 		if (timr->it_interval != 0) {
387 			ktime_t now = hrtimer_cb_get_time(timer);
388 
389 			/*
390 			 * FIXME: What we really want, is to stop this
391 			 * timer completely and restart it in case the
392 			 * SIG_IGN is removed. This is a non trivial
393 			 * change which involves sighand locking
394 			 * (sigh !), which we don't want to do late in
395 			 * the release cycle.
396 			 *
397 			 * For now we just let timers with an interval
398 			 * less than a jiffie expire every jiffie to
399 			 * avoid softirq starvation in case of SIG_IGN
400 			 * and a very small interval, which would put
401 			 * the timer right back on the softirq pending
402 			 * list. By moving now ahead of time we trick
403 			 * hrtimer_forward() to expire the timer
404 			 * later, while we still maintain the overrun
405 			 * accuracy, but have some inconsistency in
406 			 * the timer_gettime() case. This is at least
407 			 * better than a starved softirq. A more
408 			 * complex fix which solves also another related
409 			 * inconsistency is already in the pipeline.
410 			 */
411 #ifdef CONFIG_HIGH_RES_TIMERS
412 			{
413 				ktime_t kj = NSEC_PER_SEC / HZ;
414 
415 				if (timr->it_interval < kj)
416 					now = ktime_add(now, kj);
417 			}
418 #endif
419 			timr->it_overrun += hrtimer_forward(timer, now,
420 							    timr->it_interval);
421 			ret = HRTIMER_RESTART;
422 			++timr->it_requeue_pending;
423 			timr->it_active = 1;
424 		}
425 	}
426 
427 	unlock_timer(timr, flags);
428 	return ret;
429 }
430 
good_sigevent(sigevent_t * event)431 static struct pid *good_sigevent(sigevent_t * event)
432 {
433 	struct pid *pid = task_tgid(current);
434 	struct task_struct *rtn;
435 
436 	switch (event->sigev_notify) {
437 	case SIGEV_SIGNAL | SIGEV_THREAD_ID:
438 		pid = find_vpid(event->sigev_notify_thread_id);
439 		rtn = pid_task(pid, PIDTYPE_PID);
440 		if (!rtn || !same_thread_group(rtn, current))
441 			return NULL;
442 		fallthrough;
443 	case SIGEV_SIGNAL:
444 	case SIGEV_THREAD:
445 		if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX)
446 			return NULL;
447 		fallthrough;
448 	case SIGEV_NONE:
449 		return pid;
450 	default:
451 		return NULL;
452 	}
453 }
454 
alloc_posix_timer(void)455 static struct k_itimer * alloc_posix_timer(void)
456 {
457 	struct k_itimer *tmr;
458 	tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
459 	if (!tmr)
460 		return tmr;
461 	if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
462 		kmem_cache_free(posix_timers_cache, tmr);
463 		return NULL;
464 	}
465 	clear_siginfo(&tmr->sigq->info);
466 	return tmr;
467 }
468 
k_itimer_rcu_free(struct rcu_head * head)469 static void k_itimer_rcu_free(struct rcu_head *head)
470 {
471 	struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
472 
473 	kmem_cache_free(posix_timers_cache, tmr);
474 }
475 
476 #define IT_ID_SET	1
477 #define IT_ID_NOT_SET	0
release_posix_timer(struct k_itimer * tmr,int it_id_set)478 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
479 {
480 	if (it_id_set) {
481 		unsigned long flags;
482 		spin_lock_irqsave(&hash_lock, flags);
483 		hlist_del_rcu(&tmr->t_hash);
484 		spin_unlock_irqrestore(&hash_lock, flags);
485 	}
486 	put_pid(tmr->it_pid);
487 	sigqueue_free(tmr->sigq);
488 	call_rcu(&tmr->rcu, k_itimer_rcu_free);
489 }
490 
common_timer_create(struct k_itimer * new_timer)491 static int common_timer_create(struct k_itimer *new_timer)
492 {
493 	hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
494 	return 0;
495 }
496 
497 /* Create a POSIX.1b interval timer. */
do_timer_create(clockid_t which_clock,struct sigevent * event,timer_t __user * created_timer_id)498 static int do_timer_create(clockid_t which_clock, struct sigevent *event,
499 			   timer_t __user *created_timer_id)
500 {
501 	const struct k_clock *kc = clockid_to_kclock(which_clock);
502 	struct k_itimer *new_timer;
503 	int error, new_timer_id;
504 	int it_id_set = IT_ID_NOT_SET;
505 
506 	if (!kc)
507 		return -EINVAL;
508 	if (!kc->timer_create)
509 		return -EOPNOTSUPP;
510 
511 	new_timer = alloc_posix_timer();
512 	if (unlikely(!new_timer))
513 		return -EAGAIN;
514 
515 	spin_lock_init(&new_timer->it_lock);
516 	new_timer_id = posix_timer_add(new_timer);
517 	if (new_timer_id < 0) {
518 		error = new_timer_id;
519 		goto out;
520 	}
521 
522 	it_id_set = IT_ID_SET;
523 	new_timer->it_id = (timer_t) new_timer_id;
524 	new_timer->it_clock = which_clock;
525 	new_timer->kclock = kc;
526 	new_timer->it_overrun = -1LL;
527 
528 	if (event) {
529 		rcu_read_lock();
530 		new_timer->it_pid = get_pid(good_sigevent(event));
531 		rcu_read_unlock();
532 		if (!new_timer->it_pid) {
533 			error = -EINVAL;
534 			goto out;
535 		}
536 		new_timer->it_sigev_notify     = event->sigev_notify;
537 		new_timer->sigq->info.si_signo = event->sigev_signo;
538 		new_timer->sigq->info.si_value = event->sigev_value;
539 	} else {
540 		new_timer->it_sigev_notify     = SIGEV_SIGNAL;
541 		new_timer->sigq->info.si_signo = SIGALRM;
542 		memset(&new_timer->sigq->info.si_value, 0, sizeof(sigval_t));
543 		new_timer->sigq->info.si_value.sival_int = new_timer->it_id;
544 		new_timer->it_pid = get_pid(task_tgid(current));
545 	}
546 
547 	new_timer->sigq->info.si_tid   = new_timer->it_id;
548 	new_timer->sigq->info.si_code  = SI_TIMER;
549 
550 	if (copy_to_user(created_timer_id,
551 			 &new_timer_id, sizeof (new_timer_id))) {
552 		error = -EFAULT;
553 		goto out;
554 	}
555 
556 	error = kc->timer_create(new_timer);
557 	if (error)
558 		goto out;
559 
560 	spin_lock_irq(&current->sighand->siglock);
561 	new_timer->it_signal = current->signal;
562 	list_add(&new_timer->list, &current->signal->posix_timers);
563 	spin_unlock_irq(&current->sighand->siglock);
564 
565 	return 0;
566 	/*
567 	 * In the case of the timer belonging to another task, after
568 	 * the task is unlocked, the timer is owned by the other task
569 	 * and may cease to exist at any time.  Don't use or modify
570 	 * new_timer after the unlock call.
571 	 */
572 out:
573 	release_posix_timer(new_timer, it_id_set);
574 	return error;
575 }
576 
SYSCALL_DEFINE3(timer_create,const clockid_t,which_clock,struct sigevent __user *,timer_event_spec,timer_t __user *,created_timer_id)577 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
578 		struct sigevent __user *, timer_event_spec,
579 		timer_t __user *, created_timer_id)
580 {
581 	if (timer_event_spec) {
582 		sigevent_t event;
583 
584 		if (copy_from_user(&event, timer_event_spec, sizeof (event)))
585 			return -EFAULT;
586 		return do_timer_create(which_clock, &event, created_timer_id);
587 	}
588 	return do_timer_create(which_clock, NULL, created_timer_id);
589 }
590 
591 #ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(timer_create,clockid_t,which_clock,struct compat_sigevent __user *,timer_event_spec,timer_t __user *,created_timer_id)592 COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock,
593 		       struct compat_sigevent __user *, timer_event_spec,
594 		       timer_t __user *, created_timer_id)
595 {
596 	if (timer_event_spec) {
597 		sigevent_t event;
598 
599 		if (get_compat_sigevent(&event, timer_event_spec))
600 			return -EFAULT;
601 		return do_timer_create(which_clock, &event, created_timer_id);
602 	}
603 	return do_timer_create(which_clock, NULL, created_timer_id);
604 }
605 #endif
606 
607 /*
608  * Locking issues: We need to protect the result of the id look up until
609  * we get the timer locked down so it is not deleted under us.  The
610  * removal is done under the idr spinlock so we use that here to bridge
611  * the find to the timer lock.  To avoid a dead lock, the timer id MUST
612  * be release with out holding the timer lock.
613  */
__lock_timer(timer_t timer_id,unsigned long * flags)614 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
615 {
616 	struct k_itimer *timr;
617 
618 	/*
619 	 * timer_t could be any type >= int and we want to make sure any
620 	 * @timer_id outside positive int range fails lookup.
621 	 */
622 	if ((unsigned long long)timer_id > INT_MAX)
623 		return NULL;
624 
625 	rcu_read_lock();
626 	timr = posix_timer_by_id(timer_id);
627 	if (timr) {
628 		spin_lock_irqsave(&timr->it_lock, *flags);
629 		if (timr->it_signal == current->signal) {
630 			rcu_read_unlock();
631 			return timr;
632 		}
633 		spin_unlock_irqrestore(&timr->it_lock, *flags);
634 	}
635 	rcu_read_unlock();
636 
637 	return NULL;
638 }
639 
common_hrtimer_remaining(struct k_itimer * timr,ktime_t now)640 static ktime_t common_hrtimer_remaining(struct k_itimer *timr, ktime_t now)
641 {
642 	struct hrtimer *timer = &timr->it.real.timer;
643 
644 	return __hrtimer_expires_remaining_adjusted(timer, now);
645 }
646 
common_hrtimer_forward(struct k_itimer * timr,ktime_t now)647 static s64 common_hrtimer_forward(struct k_itimer *timr, ktime_t now)
648 {
649 	struct hrtimer *timer = &timr->it.real.timer;
650 
651 	return hrtimer_forward(timer, now, timr->it_interval);
652 }
653 
654 /*
655  * Get the time remaining on a POSIX.1b interval timer.  This function
656  * is ALWAYS called with spin_lock_irq on the timer, thus it must not
657  * mess with irq.
658  *
659  * We have a couple of messes to clean up here.  First there is the case
660  * of a timer that has a requeue pending.  These timers should appear to
661  * be in the timer list with an expiry as if we were to requeue them
662  * now.
663  *
664  * The second issue is the SIGEV_NONE timer which may be active but is
665  * not really ever put in the timer list (to save system resources).
666  * This timer may be expired, and if so, we will do it here.  Otherwise
667  * it is the same as a requeue pending timer WRT to what we should
668  * report.
669  */
common_timer_get(struct k_itimer * timr,struct itimerspec64 * cur_setting)670 void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
671 {
672 	const struct k_clock *kc = timr->kclock;
673 	ktime_t now, remaining, iv;
674 	bool sig_none;
675 
676 	sig_none = timr->it_sigev_notify == SIGEV_NONE;
677 	iv = timr->it_interval;
678 
679 	/* interval timer ? */
680 	if (iv) {
681 		cur_setting->it_interval = ktime_to_timespec64(iv);
682 	} else if (!timr->it_active) {
683 		/*
684 		 * SIGEV_NONE oneshot timers are never queued. Check them
685 		 * below.
686 		 */
687 		if (!sig_none)
688 			return;
689 	}
690 
691 	now = kc->clock_get_ktime(timr->it_clock);
692 
693 	/*
694 	 * When a requeue is pending or this is a SIGEV_NONE timer move the
695 	 * expiry time forward by intervals, so expiry is > now.
696 	 */
697 	if (iv && (timr->it_requeue_pending & REQUEUE_PENDING || sig_none))
698 		timr->it_overrun += kc->timer_forward(timr, now);
699 
700 	remaining = kc->timer_remaining(timr, now);
701 	/* Return 0 only, when the timer is expired and not pending */
702 	if (remaining <= 0) {
703 		/*
704 		 * A single shot SIGEV_NONE timer must return 0, when
705 		 * it is expired !
706 		 */
707 		if (!sig_none)
708 			cur_setting->it_value.tv_nsec = 1;
709 	} else {
710 		cur_setting->it_value = ktime_to_timespec64(remaining);
711 	}
712 }
713 
714 /* Get the time remaining on a POSIX.1b interval timer. */
do_timer_gettime(timer_t timer_id,struct itimerspec64 * setting)715 static int do_timer_gettime(timer_t timer_id,  struct itimerspec64 *setting)
716 {
717 	struct k_itimer *timr;
718 	const struct k_clock *kc;
719 	unsigned long flags;
720 	int ret = 0;
721 
722 	timr = lock_timer(timer_id, &flags);
723 	if (!timr)
724 		return -EINVAL;
725 
726 	memset(setting, 0, sizeof(*setting));
727 	kc = timr->kclock;
728 	if (WARN_ON_ONCE(!kc || !kc->timer_get))
729 		ret = -EINVAL;
730 	else
731 		kc->timer_get(timr, setting);
732 
733 	unlock_timer(timr, flags);
734 	return ret;
735 }
736 
737 /* Get the time remaining on a POSIX.1b interval timer. */
SYSCALL_DEFINE2(timer_gettime,timer_t,timer_id,struct __kernel_itimerspec __user *,setting)738 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
739 		struct __kernel_itimerspec __user *, setting)
740 {
741 	struct itimerspec64 cur_setting;
742 
743 	int ret = do_timer_gettime(timer_id, &cur_setting);
744 	if (!ret) {
745 		if (put_itimerspec64(&cur_setting, setting))
746 			ret = -EFAULT;
747 	}
748 	return ret;
749 }
750 
751 #ifdef CONFIG_COMPAT_32BIT_TIME
752 
SYSCALL_DEFINE2(timer_gettime32,timer_t,timer_id,struct old_itimerspec32 __user *,setting)753 SYSCALL_DEFINE2(timer_gettime32, timer_t, timer_id,
754 		struct old_itimerspec32 __user *, setting)
755 {
756 	struct itimerspec64 cur_setting;
757 
758 	int ret = do_timer_gettime(timer_id, &cur_setting);
759 	if (!ret) {
760 		if (put_old_itimerspec32(&cur_setting, setting))
761 			ret = -EFAULT;
762 	}
763 	return ret;
764 }
765 
766 #endif
767 
768 /*
769  * Get the number of overruns of a POSIX.1b interval timer.  This is to
770  * be the overrun of the timer last delivered.  At the same time we are
771  * accumulating overruns on the next timer.  The overrun is frozen when
772  * the signal is delivered, either at the notify time (if the info block
773  * is not queued) or at the actual delivery time (as we are informed by
774  * the call back to posixtimer_rearm().  So all we need to do is
775  * to pick up the frozen overrun.
776  */
SYSCALL_DEFINE1(timer_getoverrun,timer_t,timer_id)777 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
778 {
779 	struct k_itimer *timr;
780 	int overrun;
781 	unsigned long flags;
782 
783 	timr = lock_timer(timer_id, &flags);
784 	if (!timr)
785 		return -EINVAL;
786 
787 	overrun = timer_overrun_to_int(timr, 0);
788 	unlock_timer(timr, flags);
789 
790 	return overrun;
791 }
792 
common_hrtimer_arm(struct k_itimer * timr,ktime_t expires,bool absolute,bool sigev_none)793 static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
794 			       bool absolute, bool sigev_none)
795 {
796 	struct hrtimer *timer = &timr->it.real.timer;
797 	enum hrtimer_mode mode;
798 
799 	mode = absolute ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
800 	/*
801 	 * Posix magic: Relative CLOCK_REALTIME timers are not affected by
802 	 * clock modifications, so they become CLOCK_MONOTONIC based under the
803 	 * hood. See hrtimer_init(). Update timr->kclock, so the generic
804 	 * functions which use timr->kclock->clock_get_*() work.
805 	 *
806 	 * Note: it_clock stays unmodified, because the next timer_set() might
807 	 * use ABSTIME, so it needs to switch back.
808 	 */
809 	if (timr->it_clock == CLOCK_REALTIME)
810 		timr->kclock = absolute ? &clock_realtime : &clock_monotonic;
811 
812 	hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
813 	timr->it.real.timer.function = posix_timer_fn;
814 
815 	if (!absolute)
816 		expires = ktime_add_safe(expires, timer->base->get_time());
817 	hrtimer_set_expires(timer, expires);
818 
819 	if (!sigev_none)
820 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
821 }
822 
common_hrtimer_try_to_cancel(struct k_itimer * timr)823 static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
824 {
825 	return hrtimer_try_to_cancel(&timr->it.real.timer);
826 }
827 
common_timer_wait_running(struct k_itimer * timer)828 static void common_timer_wait_running(struct k_itimer *timer)
829 {
830 	hrtimer_cancel_wait_running(&timer->it.real.timer);
831 }
832 
833 /*
834  * On PREEMPT_RT this prevent priority inversion against softirq kthread in
835  * case it gets preempted while executing a timer callback. See comments in
836  * hrtimer_cancel_wait_running. For PREEMPT_RT=n this just results in a
837  * cpu_relax().
838  */
timer_wait_running(struct k_itimer * timer,unsigned long * flags)839 static struct k_itimer *timer_wait_running(struct k_itimer *timer,
840 					   unsigned long *flags)
841 {
842 	const struct k_clock *kc = READ_ONCE(timer->kclock);
843 	timer_t timer_id = READ_ONCE(timer->it_id);
844 
845 	/* Prevent kfree(timer) after dropping the lock */
846 	rcu_read_lock();
847 	unlock_timer(timer, *flags);
848 
849 	if (!WARN_ON_ONCE(!kc->timer_wait_running))
850 		kc->timer_wait_running(timer);
851 
852 	rcu_read_unlock();
853 	/* Relock the timer. It might be not longer hashed. */
854 	return lock_timer(timer_id, flags);
855 }
856 
857 /* Set a POSIX.1b interval timer. */
common_timer_set(struct k_itimer * timr,int flags,struct itimerspec64 * new_setting,struct itimerspec64 * old_setting)858 int common_timer_set(struct k_itimer *timr, int flags,
859 		     struct itimerspec64 *new_setting,
860 		     struct itimerspec64 *old_setting)
861 {
862 	const struct k_clock *kc = timr->kclock;
863 	bool sigev_none;
864 	ktime_t expires;
865 
866 	if (old_setting)
867 		common_timer_get(timr, old_setting);
868 
869 	/* Prevent rearming by clearing the interval */
870 	timr->it_interval = 0;
871 	/*
872 	 * Careful here. On SMP systems the timer expiry function could be
873 	 * active and spinning on timr->it_lock.
874 	 */
875 	if (kc->timer_try_to_cancel(timr) < 0)
876 		return TIMER_RETRY;
877 
878 	timr->it_active = 0;
879 	timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
880 		~REQUEUE_PENDING;
881 	timr->it_overrun_last = 0;
882 
883 	/* Switch off the timer when it_value is zero */
884 	if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
885 		return 0;
886 
887 	timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
888 	expires = timespec64_to_ktime(new_setting->it_value);
889 	if (flags & TIMER_ABSTIME)
890 		expires = timens_ktime_to_host(timr->it_clock, expires);
891 	sigev_none = timr->it_sigev_notify == SIGEV_NONE;
892 
893 	kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);
894 	timr->it_active = !sigev_none;
895 	return 0;
896 }
897 
do_timer_settime(timer_t timer_id,int tmr_flags,struct itimerspec64 * new_spec64,struct itimerspec64 * old_spec64)898 static int do_timer_settime(timer_t timer_id, int tmr_flags,
899 			    struct itimerspec64 *new_spec64,
900 			    struct itimerspec64 *old_spec64)
901 {
902 	const struct k_clock *kc;
903 	struct k_itimer *timr;
904 	unsigned long flags;
905 	int error = 0;
906 
907 	if (!timespec64_valid(&new_spec64->it_interval) ||
908 	    !timespec64_valid(&new_spec64->it_value))
909 		return -EINVAL;
910 
911 	if (old_spec64)
912 		memset(old_spec64, 0, sizeof(*old_spec64));
913 
914 	timr = lock_timer(timer_id, &flags);
915 retry:
916 	if (!timr)
917 		return -EINVAL;
918 
919 	kc = timr->kclock;
920 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
921 		error = -EINVAL;
922 	else
923 		error = kc->timer_set(timr, tmr_flags, new_spec64, old_spec64);
924 
925 	if (error == TIMER_RETRY) {
926 		// We already got the old time...
927 		old_spec64 = NULL;
928 		/* Unlocks and relocks the timer if it still exists */
929 		timr = timer_wait_running(timr, &flags);
930 		goto retry;
931 	}
932 	unlock_timer(timr, flags);
933 
934 	return error;
935 }
936 
937 /* Set a POSIX.1b interval timer */
SYSCALL_DEFINE4(timer_settime,timer_t,timer_id,int,flags,const struct __kernel_itimerspec __user *,new_setting,struct __kernel_itimerspec __user *,old_setting)938 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
939 		const struct __kernel_itimerspec __user *, new_setting,
940 		struct __kernel_itimerspec __user *, old_setting)
941 {
942 	struct itimerspec64 new_spec, old_spec;
943 	struct itimerspec64 *rtn = old_setting ? &old_spec : NULL;
944 	int error = 0;
945 
946 	if (!new_setting)
947 		return -EINVAL;
948 
949 	if (get_itimerspec64(&new_spec, new_setting))
950 		return -EFAULT;
951 
952 	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
953 	if (!error && old_setting) {
954 		if (put_itimerspec64(&old_spec, old_setting))
955 			error = -EFAULT;
956 	}
957 	return error;
958 }
959 
960 #ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE4(timer_settime32,timer_t,timer_id,int,flags,struct old_itimerspec32 __user *,new,struct old_itimerspec32 __user *,old)961 SYSCALL_DEFINE4(timer_settime32, timer_t, timer_id, int, flags,
962 		struct old_itimerspec32 __user *, new,
963 		struct old_itimerspec32 __user *, old)
964 {
965 	struct itimerspec64 new_spec, old_spec;
966 	struct itimerspec64 *rtn = old ? &old_spec : NULL;
967 	int error = 0;
968 
969 	if (!new)
970 		return -EINVAL;
971 	if (get_old_itimerspec32(&new_spec, new))
972 		return -EFAULT;
973 
974 	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
975 	if (!error && old) {
976 		if (put_old_itimerspec32(&old_spec, old))
977 			error = -EFAULT;
978 	}
979 	return error;
980 }
981 #endif
982 
common_timer_del(struct k_itimer * timer)983 int common_timer_del(struct k_itimer *timer)
984 {
985 	const struct k_clock *kc = timer->kclock;
986 
987 	timer->it_interval = 0;
988 	if (kc->timer_try_to_cancel(timer) < 0)
989 		return TIMER_RETRY;
990 	timer->it_active = 0;
991 	return 0;
992 }
993 
timer_delete_hook(struct k_itimer * timer)994 static inline int timer_delete_hook(struct k_itimer *timer)
995 {
996 	const struct k_clock *kc = timer->kclock;
997 
998 	if (WARN_ON_ONCE(!kc || !kc->timer_del))
999 		return -EINVAL;
1000 	return kc->timer_del(timer);
1001 }
1002 
1003 /* Delete a POSIX.1b interval timer. */
SYSCALL_DEFINE1(timer_delete,timer_t,timer_id)1004 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
1005 {
1006 	struct k_itimer *timer;
1007 	unsigned long flags;
1008 
1009 	timer = lock_timer(timer_id, &flags);
1010 
1011 retry_delete:
1012 	if (!timer)
1013 		return -EINVAL;
1014 
1015 	if (unlikely(timer_delete_hook(timer) == TIMER_RETRY)) {
1016 		/* Unlocks and relocks the timer if it still exists */
1017 		timer = timer_wait_running(timer, &flags);
1018 		goto retry_delete;
1019 	}
1020 
1021 	spin_lock(&current->sighand->siglock);
1022 	list_del(&timer->list);
1023 	spin_unlock(&current->sighand->siglock);
1024 	/*
1025 	 * This keeps any tasks waiting on the spin lock from thinking
1026 	 * they got something (see the lock code above).
1027 	 */
1028 	timer->it_signal = NULL;
1029 
1030 	unlock_timer(timer, flags);
1031 	release_posix_timer(timer, IT_ID_SET);
1032 	return 0;
1033 }
1034 
1035 /*
1036  * return timer owned by the process, used by exit_itimers
1037  */
itimer_delete(struct k_itimer * timer)1038 static void itimer_delete(struct k_itimer *timer)
1039 {
1040 retry_delete:
1041 	spin_lock_irq(&timer->it_lock);
1042 
1043 	if (timer_delete_hook(timer) == TIMER_RETRY) {
1044 		spin_unlock_irq(&timer->it_lock);
1045 		goto retry_delete;
1046 	}
1047 	list_del(&timer->list);
1048 
1049 	spin_unlock_irq(&timer->it_lock);
1050 	release_posix_timer(timer, IT_ID_SET);
1051 }
1052 
1053 /*
1054  * This is called by do_exit or de_thread, only when nobody else can
1055  * modify the signal->posix_timers list. Yet we need sighand->siglock
1056  * to prevent the race with /proc/pid/timers.
1057  */
exit_itimers(struct task_struct * tsk)1058 void exit_itimers(struct task_struct *tsk)
1059 {
1060 	struct list_head timers;
1061 	struct k_itimer *tmr;
1062 
1063 	if (list_empty(&tsk->signal->posix_timers))
1064 		return;
1065 
1066 	spin_lock_irq(&tsk->sighand->siglock);
1067 	list_replace_init(&tsk->signal->posix_timers, &timers);
1068 	spin_unlock_irq(&tsk->sighand->siglock);
1069 
1070 	while (!list_empty(&timers)) {
1071 		tmr = list_first_entry(&timers, struct k_itimer, list);
1072 		itimer_delete(tmr);
1073 	}
1074 }
1075 
SYSCALL_DEFINE2(clock_settime,const clockid_t,which_clock,const struct __kernel_timespec __user *,tp)1076 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1077 		const struct __kernel_timespec __user *, tp)
1078 {
1079 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1080 	struct timespec64 new_tp;
1081 
1082 	if (!kc || !kc->clock_set)
1083 		return -EINVAL;
1084 
1085 	if (get_timespec64(&new_tp, tp))
1086 		return -EFAULT;
1087 
1088 	return kc->clock_set(which_clock, &new_tp);
1089 }
1090 
SYSCALL_DEFINE2(clock_gettime,const clockid_t,which_clock,struct __kernel_timespec __user *,tp)1091 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1092 		struct __kernel_timespec __user *, tp)
1093 {
1094 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1095 	struct timespec64 kernel_tp;
1096 	int error;
1097 
1098 	if (!kc)
1099 		return -EINVAL;
1100 
1101 	error = kc->clock_get_timespec(which_clock, &kernel_tp);
1102 
1103 	if (!error && put_timespec64(&kernel_tp, tp))
1104 		error = -EFAULT;
1105 
1106 	return error;
1107 }
1108 
do_clock_adjtime(const clockid_t which_clock,struct __kernel_timex * ktx)1109 int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * ktx)
1110 {
1111 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1112 
1113 	if (!kc)
1114 		return -EINVAL;
1115 	if (!kc->clock_adj)
1116 		return -EOPNOTSUPP;
1117 
1118 	return kc->clock_adj(which_clock, ktx);
1119 }
1120 
SYSCALL_DEFINE2(clock_adjtime,const clockid_t,which_clock,struct __kernel_timex __user *,utx)1121 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1122 		struct __kernel_timex __user *, utx)
1123 {
1124 	struct __kernel_timex ktx;
1125 	int err;
1126 
1127 	if (copy_from_user(&ktx, utx, sizeof(ktx)))
1128 		return -EFAULT;
1129 
1130 	err = do_clock_adjtime(which_clock, &ktx);
1131 
1132 	if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1133 		return -EFAULT;
1134 
1135 	return err;
1136 }
1137 
SYSCALL_DEFINE2(clock_getres,const clockid_t,which_clock,struct __kernel_timespec __user *,tp)1138 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1139 		struct __kernel_timespec __user *, tp)
1140 {
1141 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1142 	struct timespec64 rtn_tp;
1143 	int error;
1144 
1145 	if (!kc)
1146 		return -EINVAL;
1147 
1148 	error = kc->clock_getres(which_clock, &rtn_tp);
1149 
1150 	if (!error && tp && put_timespec64(&rtn_tp, tp))
1151 		error = -EFAULT;
1152 
1153 	return error;
1154 }
1155 
1156 #ifdef CONFIG_COMPAT_32BIT_TIME
1157 
SYSCALL_DEFINE2(clock_settime32,clockid_t,which_clock,struct old_timespec32 __user *,tp)1158 SYSCALL_DEFINE2(clock_settime32, clockid_t, which_clock,
1159 		struct old_timespec32 __user *, tp)
1160 {
1161 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1162 	struct timespec64 ts;
1163 
1164 	if (!kc || !kc->clock_set)
1165 		return -EINVAL;
1166 
1167 	if (get_old_timespec32(&ts, tp))
1168 		return -EFAULT;
1169 
1170 	return kc->clock_set(which_clock, &ts);
1171 }
1172 
SYSCALL_DEFINE2(clock_gettime32,clockid_t,which_clock,struct old_timespec32 __user *,tp)1173 SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
1174 		struct old_timespec32 __user *, tp)
1175 {
1176 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1177 	struct timespec64 ts;
1178 	int err;
1179 
1180 	if (!kc)
1181 		return -EINVAL;
1182 
1183 	err = kc->clock_get_timespec(which_clock, &ts);
1184 
1185 	if (!err && put_old_timespec32(&ts, tp))
1186 		err = -EFAULT;
1187 
1188 	return err;
1189 }
1190 
SYSCALL_DEFINE2(clock_adjtime32,clockid_t,which_clock,struct old_timex32 __user *,utp)1191 SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
1192 		struct old_timex32 __user *, utp)
1193 {
1194 	struct __kernel_timex ktx;
1195 	int err;
1196 
1197 	err = get_old_timex32(&ktx, utp);
1198 	if (err)
1199 		return err;
1200 
1201 	err = do_clock_adjtime(which_clock, &ktx);
1202 
1203 	if (err >= 0 && put_old_timex32(utp, &ktx))
1204 		return -EFAULT;
1205 
1206 	return err;
1207 }
1208 
SYSCALL_DEFINE2(clock_getres_time32,clockid_t,which_clock,struct old_timespec32 __user *,tp)1209 SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
1210 		struct old_timespec32 __user *, tp)
1211 {
1212 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1213 	struct timespec64 ts;
1214 	int err;
1215 
1216 	if (!kc)
1217 		return -EINVAL;
1218 
1219 	err = kc->clock_getres(which_clock, &ts);
1220 	if (!err && tp && put_old_timespec32(&ts, tp))
1221 		return -EFAULT;
1222 
1223 	return err;
1224 }
1225 
1226 #endif
1227 
1228 /*
1229  * nanosleep for monotonic and realtime clocks
1230  */
common_nsleep(const clockid_t which_clock,int flags,const struct timespec64 * rqtp)1231 static int common_nsleep(const clockid_t which_clock, int flags,
1232 			 const struct timespec64 *rqtp)
1233 {
1234 	ktime_t texp = timespec64_to_ktime(*rqtp);
1235 
1236 	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
1237 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1238 				 which_clock);
1239 }
1240 
common_nsleep_timens(const clockid_t which_clock,int flags,const struct timespec64 * rqtp)1241 static int common_nsleep_timens(const clockid_t which_clock, int flags,
1242 			 const struct timespec64 *rqtp)
1243 {
1244 	ktime_t texp = timespec64_to_ktime(*rqtp);
1245 
1246 	if (flags & TIMER_ABSTIME)
1247 		texp = timens_ktime_to_host(which_clock, texp);
1248 
1249 	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
1250 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1251 				 which_clock);
1252 }
1253 
SYSCALL_DEFINE4(clock_nanosleep,const clockid_t,which_clock,int,flags,const struct __kernel_timespec __user *,rqtp,struct __kernel_timespec __user *,rmtp)1254 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1255 		const struct __kernel_timespec __user *, rqtp,
1256 		struct __kernel_timespec __user *, rmtp)
1257 {
1258 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1259 	struct timespec64 t;
1260 
1261 	if (!kc)
1262 		return -EINVAL;
1263 	if (!kc->nsleep)
1264 		return -EOPNOTSUPP;
1265 
1266 	if (get_timespec64(&t, rqtp))
1267 		return -EFAULT;
1268 
1269 	if (!timespec64_valid(&t))
1270 		return -EINVAL;
1271 	if (flags & TIMER_ABSTIME)
1272 		rmtp = NULL;
1273 	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
1274 	current->restart_block.nanosleep.rmtp = rmtp;
1275 
1276 	return kc->nsleep(which_clock, flags, &t);
1277 }
1278 
1279 #ifdef CONFIG_COMPAT_32BIT_TIME
1280 
SYSCALL_DEFINE4(clock_nanosleep_time32,clockid_t,which_clock,int,flags,struct old_timespec32 __user *,rqtp,struct old_timespec32 __user *,rmtp)1281 SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
1282 		struct old_timespec32 __user *, rqtp,
1283 		struct old_timespec32 __user *, rmtp)
1284 {
1285 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1286 	struct timespec64 t;
1287 
1288 	if (!kc)
1289 		return -EINVAL;
1290 	if (!kc->nsleep)
1291 		return -EOPNOTSUPP;
1292 
1293 	if (get_old_timespec32(&t, rqtp))
1294 		return -EFAULT;
1295 
1296 	if (!timespec64_valid(&t))
1297 		return -EINVAL;
1298 	if (flags & TIMER_ABSTIME)
1299 		rmtp = NULL;
1300 	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
1301 	current->restart_block.nanosleep.compat_rmtp = rmtp;
1302 
1303 	return kc->nsleep(which_clock, flags, &t);
1304 }
1305 
1306 #endif
1307 
1308 static const struct k_clock clock_realtime = {
1309 	.clock_getres		= posix_get_hrtimer_res,
1310 	.clock_get_timespec	= posix_get_realtime_timespec,
1311 	.clock_get_ktime	= posix_get_realtime_ktime,
1312 	.clock_set		= posix_clock_realtime_set,
1313 	.clock_adj		= posix_clock_realtime_adj,
1314 	.nsleep			= common_nsleep,
1315 	.timer_create		= common_timer_create,
1316 	.timer_set		= common_timer_set,
1317 	.timer_get		= common_timer_get,
1318 	.timer_del		= common_timer_del,
1319 	.timer_rearm		= common_hrtimer_rearm,
1320 	.timer_forward		= common_hrtimer_forward,
1321 	.timer_remaining	= common_hrtimer_remaining,
1322 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1323 	.timer_wait_running	= common_timer_wait_running,
1324 	.timer_arm		= common_hrtimer_arm,
1325 };
1326 
1327 static const struct k_clock clock_monotonic = {
1328 	.clock_getres		= posix_get_hrtimer_res,
1329 	.clock_get_timespec	= posix_get_monotonic_timespec,
1330 	.clock_get_ktime	= posix_get_monotonic_ktime,
1331 	.nsleep			= common_nsleep_timens,
1332 	.timer_create		= common_timer_create,
1333 	.timer_set		= common_timer_set,
1334 	.timer_get		= common_timer_get,
1335 	.timer_del		= common_timer_del,
1336 	.timer_rearm		= common_hrtimer_rearm,
1337 	.timer_forward		= common_hrtimer_forward,
1338 	.timer_remaining	= common_hrtimer_remaining,
1339 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1340 	.timer_wait_running	= common_timer_wait_running,
1341 	.timer_arm		= common_hrtimer_arm,
1342 };
1343 
1344 static const struct k_clock clock_monotonic_raw = {
1345 	.clock_getres		= posix_get_hrtimer_res,
1346 	.clock_get_timespec	= posix_get_monotonic_raw,
1347 };
1348 
1349 static const struct k_clock clock_realtime_coarse = {
1350 	.clock_getres		= posix_get_coarse_res,
1351 	.clock_get_timespec	= posix_get_realtime_coarse,
1352 };
1353 
1354 static const struct k_clock clock_monotonic_coarse = {
1355 	.clock_getres		= posix_get_coarse_res,
1356 	.clock_get_timespec	= posix_get_monotonic_coarse,
1357 };
1358 
1359 static const struct k_clock clock_tai = {
1360 	.clock_getres		= posix_get_hrtimer_res,
1361 	.clock_get_ktime	= posix_get_tai_ktime,
1362 	.clock_get_timespec	= posix_get_tai_timespec,
1363 	.nsleep			= common_nsleep,
1364 	.timer_create		= common_timer_create,
1365 	.timer_set		= common_timer_set,
1366 	.timer_get		= common_timer_get,
1367 	.timer_del		= common_timer_del,
1368 	.timer_rearm		= common_hrtimer_rearm,
1369 	.timer_forward		= common_hrtimer_forward,
1370 	.timer_remaining	= common_hrtimer_remaining,
1371 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1372 	.timer_wait_running	= common_timer_wait_running,
1373 	.timer_arm		= common_hrtimer_arm,
1374 };
1375 
1376 static const struct k_clock clock_boottime = {
1377 	.clock_getres		= posix_get_hrtimer_res,
1378 	.clock_get_ktime	= posix_get_boottime_ktime,
1379 	.clock_get_timespec	= posix_get_boottime_timespec,
1380 	.nsleep			= common_nsleep_timens,
1381 	.timer_create		= common_timer_create,
1382 	.timer_set		= common_timer_set,
1383 	.timer_get		= common_timer_get,
1384 	.timer_del		= common_timer_del,
1385 	.timer_rearm		= common_hrtimer_rearm,
1386 	.timer_forward		= common_hrtimer_forward,
1387 	.timer_remaining	= common_hrtimer_remaining,
1388 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1389 	.timer_wait_running	= common_timer_wait_running,
1390 	.timer_arm		= common_hrtimer_arm,
1391 };
1392 
1393 static const struct k_clock * const posix_clocks[] = {
1394 	[CLOCK_REALTIME]		= &clock_realtime,
1395 	[CLOCK_MONOTONIC]		= &clock_monotonic,
1396 	[CLOCK_PROCESS_CPUTIME_ID]	= &clock_process,
1397 	[CLOCK_THREAD_CPUTIME_ID]	= &clock_thread,
1398 	[CLOCK_MONOTONIC_RAW]		= &clock_monotonic_raw,
1399 	[CLOCK_REALTIME_COARSE]		= &clock_realtime_coarse,
1400 	[CLOCK_MONOTONIC_COARSE]	= &clock_monotonic_coarse,
1401 	[CLOCK_BOOTTIME]		= &clock_boottime,
1402 	[CLOCK_REALTIME_ALARM]		= &alarm_clock,
1403 	[CLOCK_BOOTTIME_ALARM]		= &alarm_clock,
1404 	[CLOCK_TAI]			= &clock_tai,
1405 };
1406 
clockid_to_kclock(const clockid_t id)1407 static const struct k_clock *clockid_to_kclock(const clockid_t id)
1408 {
1409 	clockid_t idx = id;
1410 
1411 	if (id < 0) {
1412 		return (id & CLOCKFD_MASK) == CLOCKFD ?
1413 			&clock_posix_dynamic : &clock_posix_cpu;
1414 	}
1415 
1416 	if (id >= ARRAY_SIZE(posix_clocks))
1417 		return NULL;
1418 
1419 	return posix_clocks[array_index_nospec(idx, ARRAY_SIZE(posix_clocks))];
1420 }
1421