xref: /openbmc/linux/kernel/time/posix-timers.c (revision 8ee90c5c)
1 /*
2  * linux/kernel/posix-timers.c
3  *
4  *
5  * 2002-10-15  Posix Clocks & timers
6  *                           by George Anzinger george@mvista.com
7  *
8  *			     Copyright (C) 2002 2003 by MontaVista Software.
9  *
10  * 2004-06-01  Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
11  *			     Copyright (C) 2004 Boris Hu
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or (at
16  * your option) any later version.
17  *
18  * This program is distributed in the hope that it will be useful, but
19  * WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21  * General Public License for more details.
22 
23  * You should have received a copy of the GNU General Public License
24  * along with this program; if not, write to the Free Software
25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26  *
27  * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
28  */
29 
30 /* These are all the functions necessary to implement
31  * POSIX clocks & timers
32  */
33 #include <linux/mm.h>
34 #include <linux/interrupt.h>
35 #include <linux/slab.h>
36 #include <linux/time.h>
37 #include <linux/mutex.h>
38 #include <linux/sched/task.h>
39 
40 #include <linux/uaccess.h>
41 #include <linux/list.h>
42 #include <linux/init.h>
43 #include <linux/compiler.h>
44 #include <linux/hash.h>
45 #include <linux/posix-clock.h>
46 #include <linux/posix-timers.h>
47 #include <linux/syscalls.h>
48 #include <linux/wait.h>
49 #include <linux/workqueue.h>
50 #include <linux/export.h>
51 #include <linux/hashtable.h>
52 #include <linux/compat.h>
53 
54 #include "timekeeping.h"
55 #include "posix-timers.h"
56 
57 /*
58  * Management arrays for POSIX timers. Timers are now kept in static hash table
59  * with 512 entries.
60  * Timer ids are allocated by local routine, which selects proper hash head by
61  * key, constructed from current->signal address and per signal struct counter.
62  * This keeps timer ids unique per process, but now they can intersect between
63  * processes.
64  */
65 
66 /*
67  * Lets keep our timers in a slab cache :-)
68  */
69 static struct kmem_cache *posix_timers_cache;
70 
71 static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
72 static DEFINE_SPINLOCK(hash_lock);
73 
74 static const struct k_clock * const posix_clocks[];
75 static const struct k_clock *clockid_to_kclock(const clockid_t id);
76 static const struct k_clock clock_realtime, clock_monotonic;
77 
78 /*
79  * we assume that the new SIGEV_THREAD_ID shares no bits with the other
80  * SIGEV values.  Here we put out an error if this assumption fails.
81  */
82 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
83                        ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
84 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
85 #endif
86 
87 /*
88  * parisc wants ENOTSUP instead of EOPNOTSUPP
89  */
90 #ifndef ENOTSUP
91 # define ENANOSLEEP_NOTSUP EOPNOTSUPP
92 #else
93 # define ENANOSLEEP_NOTSUP ENOTSUP
94 #endif
95 
96 /*
97  * The timer ID is turned into a timer address by idr_find().
98  * Verifying a valid ID consists of:
99  *
100  * a) checking that idr_find() returns other than -1.
101  * b) checking that the timer id matches the one in the timer itself.
102  * c) that the timer owner is in the callers thread group.
103  */
104 
105 /*
106  * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
107  *	    to implement others.  This structure defines the various
108  *	    clocks.
109  *
110  * RESOLUTION: Clock resolution is used to round up timer and interval
111  *	    times, NOT to report clock times, which are reported with as
112  *	    much resolution as the system can muster.  In some cases this
113  *	    resolution may depend on the underlying clock hardware and
114  *	    may not be quantifiable until run time, and only then is the
115  *	    necessary code is written.	The standard says we should say
116  *	    something about this issue in the documentation...
117  *
118  * FUNCTIONS: The CLOCKs structure defines possible functions to
119  *	    handle various clock functions.
120  *
121  *	    The standard POSIX timer management code assumes the
122  *	    following: 1.) The k_itimer struct (sched.h) is used for
123  *	    the timer.  2.) The list, it_lock, it_clock, it_id and
124  *	    it_pid fields are not modified by timer code.
125  *
126  * Permissions: It is assumed that the clock_settime() function defined
127  *	    for each clock will take care of permission checks.	 Some
128  *	    clocks may be set able by any user (i.e. local process
129  *	    clocks) others not.	 Currently the only set able clock we
130  *	    have is CLOCK_REALTIME and its high res counter part, both of
131  *	    which we beg off on and pass to do_sys_settimeofday().
132  */
133 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
134 
135 #define lock_timer(tid, flags)						   \
136 ({	struct k_itimer *__timr;					   \
137 	__cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags));  \
138 	__timr;								   \
139 })
140 
141 static int hash(struct signal_struct *sig, unsigned int nr)
142 {
143 	return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
144 }
145 
146 static struct k_itimer *__posix_timers_find(struct hlist_head *head,
147 					    struct signal_struct *sig,
148 					    timer_t id)
149 {
150 	struct k_itimer *timer;
151 
152 	hlist_for_each_entry_rcu(timer, head, t_hash) {
153 		if ((timer->it_signal == sig) && (timer->it_id == id))
154 			return timer;
155 	}
156 	return NULL;
157 }
158 
159 static struct k_itimer *posix_timer_by_id(timer_t id)
160 {
161 	struct signal_struct *sig = current->signal;
162 	struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
163 
164 	return __posix_timers_find(head, sig, id);
165 }
166 
167 static int posix_timer_add(struct k_itimer *timer)
168 {
169 	struct signal_struct *sig = current->signal;
170 	int first_free_id = sig->posix_timer_id;
171 	struct hlist_head *head;
172 	int ret = -ENOENT;
173 
174 	do {
175 		spin_lock(&hash_lock);
176 		head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
177 		if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
178 			hlist_add_head_rcu(&timer->t_hash, head);
179 			ret = sig->posix_timer_id;
180 		}
181 		if (++sig->posix_timer_id < 0)
182 			sig->posix_timer_id = 0;
183 		if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
184 			/* Loop over all possible ids completed */
185 			ret = -EAGAIN;
186 		spin_unlock(&hash_lock);
187 	} while (ret == -ENOENT);
188 	return ret;
189 }
190 
191 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
192 {
193 	spin_unlock_irqrestore(&timr->it_lock, flags);
194 }
195 
196 /* Get clock_realtime */
197 static int posix_clock_realtime_get(clockid_t which_clock, struct timespec64 *tp)
198 {
199 	ktime_get_real_ts64(tp);
200 	return 0;
201 }
202 
203 /* Set clock_realtime */
204 static int posix_clock_realtime_set(const clockid_t which_clock,
205 				    const struct timespec64 *tp)
206 {
207 	return do_sys_settimeofday64(tp, NULL);
208 }
209 
210 static int posix_clock_realtime_adj(const clockid_t which_clock,
211 				    struct timex *t)
212 {
213 	return do_adjtimex(t);
214 }
215 
216 /*
217  * Get monotonic time for posix timers
218  */
219 static int posix_ktime_get_ts(clockid_t which_clock, struct timespec64 *tp)
220 {
221 	ktime_get_ts64(tp);
222 	return 0;
223 }
224 
225 /*
226  * Get monotonic-raw time for posix timers
227  */
228 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec64 *tp)
229 {
230 	getrawmonotonic64(tp);
231 	return 0;
232 }
233 
234 
235 static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec64 *tp)
236 {
237 	*tp = current_kernel_time64();
238 	return 0;
239 }
240 
241 static int posix_get_monotonic_coarse(clockid_t which_clock,
242 						struct timespec64 *tp)
243 {
244 	*tp = get_monotonic_coarse64();
245 	return 0;
246 }
247 
248 static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *tp)
249 {
250 	*tp = ktime_to_timespec64(KTIME_LOW_RES);
251 	return 0;
252 }
253 
254 static int posix_get_boottime(const clockid_t which_clock, struct timespec64 *tp)
255 {
256 	get_monotonic_boottime64(tp);
257 	return 0;
258 }
259 
260 static int posix_get_tai(clockid_t which_clock, struct timespec64 *tp)
261 {
262 	timekeeping_clocktai64(tp);
263 	return 0;
264 }
265 
266 static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
267 {
268 	tp->tv_sec = 0;
269 	tp->tv_nsec = hrtimer_resolution;
270 	return 0;
271 }
272 
273 /*
274  * Initialize everything, well, just everything in Posix clocks/timers ;)
275  */
276 static __init int init_posix_timers(void)
277 {
278 	posix_timers_cache = kmem_cache_create("posix_timers_cache",
279 					sizeof (struct k_itimer), 0, SLAB_PANIC,
280 					NULL);
281 	return 0;
282 }
283 __initcall(init_posix_timers);
284 
285 static void common_hrtimer_rearm(struct k_itimer *timr)
286 {
287 	struct hrtimer *timer = &timr->it.real.timer;
288 
289 	if (!timr->it_interval)
290 		return;
291 
292 	timr->it_overrun += (unsigned int) hrtimer_forward(timer,
293 						timer->base->get_time(),
294 						timr->it_interval);
295 	hrtimer_restart(timer);
296 }
297 
298 /*
299  * This function is exported for use by the signal deliver code.  It is
300  * called just prior to the info block being released and passes that
301  * block to us.  It's function is to update the overrun entry AND to
302  * restart the timer.  It should only be called if the timer is to be
303  * restarted (i.e. we have flagged this in the sys_private entry of the
304  * info block).
305  *
306  * To protect against the timer going away while the interrupt is queued,
307  * we require that the it_requeue_pending flag be set.
308  */
309 void posixtimer_rearm(struct siginfo *info)
310 {
311 	struct k_itimer *timr;
312 	unsigned long flags;
313 
314 	timr = lock_timer(info->si_tid, &flags);
315 	if (!timr)
316 		return;
317 
318 	if (timr->it_requeue_pending == info->si_sys_private) {
319 		timr->kclock->timer_rearm(timr);
320 
321 		timr->it_active = 1;
322 		timr->it_overrun_last = timr->it_overrun;
323 		timr->it_overrun = -1;
324 		++timr->it_requeue_pending;
325 
326 		info->si_overrun += timr->it_overrun_last;
327 	}
328 
329 	unlock_timer(timr, flags);
330 }
331 
332 int posix_timer_event(struct k_itimer *timr, int si_private)
333 {
334 	struct task_struct *task;
335 	int shared, ret = -1;
336 	/*
337 	 * FIXME: if ->sigq is queued we can race with
338 	 * dequeue_signal()->posixtimer_rearm().
339 	 *
340 	 * If dequeue_signal() sees the "right" value of
341 	 * si_sys_private it calls posixtimer_rearm().
342 	 * We re-queue ->sigq and drop ->it_lock().
343 	 * posixtimer_rearm() locks the timer
344 	 * and re-schedules it while ->sigq is pending.
345 	 * Not really bad, but not that we want.
346 	 */
347 	timr->sigq->info.si_sys_private = si_private;
348 
349 	rcu_read_lock();
350 	task = pid_task(timr->it_pid, PIDTYPE_PID);
351 	if (task) {
352 		shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
353 		ret = send_sigqueue(timr->sigq, task, shared);
354 	}
355 	rcu_read_unlock();
356 	/* If we failed to send the signal the timer stops. */
357 	return ret > 0;
358 }
359 
360 /*
361  * This function gets called when a POSIX.1b interval timer expires.  It
362  * is used as a callback from the kernel internal timer.  The
363  * run_timer_list code ALWAYS calls with interrupts on.
364 
365  * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
366  */
367 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
368 {
369 	struct k_itimer *timr;
370 	unsigned long flags;
371 	int si_private = 0;
372 	enum hrtimer_restart ret = HRTIMER_NORESTART;
373 
374 	timr = container_of(timer, struct k_itimer, it.real.timer);
375 	spin_lock_irqsave(&timr->it_lock, flags);
376 
377 	timr->it_active = 0;
378 	if (timr->it_interval != 0)
379 		si_private = ++timr->it_requeue_pending;
380 
381 	if (posix_timer_event(timr, si_private)) {
382 		/*
383 		 * signal was not sent because of sig_ignor
384 		 * we will not get a call back to restart it AND
385 		 * it should be restarted.
386 		 */
387 		if (timr->it_interval != 0) {
388 			ktime_t now = hrtimer_cb_get_time(timer);
389 
390 			/*
391 			 * FIXME: What we really want, is to stop this
392 			 * timer completely and restart it in case the
393 			 * SIG_IGN is removed. This is a non trivial
394 			 * change which involves sighand locking
395 			 * (sigh !), which we don't want to do late in
396 			 * the release cycle.
397 			 *
398 			 * For now we just let timers with an interval
399 			 * less than a jiffie expire every jiffie to
400 			 * avoid softirq starvation in case of SIG_IGN
401 			 * and a very small interval, which would put
402 			 * the timer right back on the softirq pending
403 			 * list. By moving now ahead of time we trick
404 			 * hrtimer_forward() to expire the timer
405 			 * later, while we still maintain the overrun
406 			 * accuracy, but have some inconsistency in
407 			 * the timer_gettime() case. This is at least
408 			 * better than a starved softirq. A more
409 			 * complex fix which solves also another related
410 			 * inconsistency is already in the pipeline.
411 			 */
412 #ifdef CONFIG_HIGH_RES_TIMERS
413 			{
414 				ktime_t kj = NSEC_PER_SEC / HZ;
415 
416 				if (timr->it_interval < kj)
417 					now = ktime_add(now, kj);
418 			}
419 #endif
420 			timr->it_overrun += (unsigned int)
421 				hrtimer_forward(timer, now,
422 						timr->it_interval);
423 			ret = HRTIMER_RESTART;
424 			++timr->it_requeue_pending;
425 			timr->it_active = 1;
426 		}
427 	}
428 
429 	unlock_timer(timr, flags);
430 	return ret;
431 }
432 
433 static struct pid *good_sigevent(sigevent_t * event)
434 {
435 	struct task_struct *rtn = current->group_leader;
436 
437 	if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
438 		(!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
439 		 !same_thread_group(rtn, current) ||
440 		 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
441 		return NULL;
442 
443 	if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
444 	    ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
445 		return NULL;
446 
447 	return task_pid(rtn);
448 }
449 
450 static struct k_itimer * alloc_posix_timer(void)
451 {
452 	struct k_itimer *tmr;
453 	tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
454 	if (!tmr)
455 		return tmr;
456 	if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
457 		kmem_cache_free(posix_timers_cache, tmr);
458 		return NULL;
459 	}
460 	memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
461 	return tmr;
462 }
463 
464 static void k_itimer_rcu_free(struct rcu_head *head)
465 {
466 	struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
467 
468 	kmem_cache_free(posix_timers_cache, tmr);
469 }
470 
471 #define IT_ID_SET	1
472 #define IT_ID_NOT_SET	0
473 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
474 {
475 	if (it_id_set) {
476 		unsigned long flags;
477 		spin_lock_irqsave(&hash_lock, flags);
478 		hlist_del_rcu(&tmr->t_hash);
479 		spin_unlock_irqrestore(&hash_lock, flags);
480 	}
481 	put_pid(tmr->it_pid);
482 	sigqueue_free(tmr->sigq);
483 	call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
484 }
485 
486 static int common_timer_create(struct k_itimer *new_timer)
487 {
488 	hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
489 	return 0;
490 }
491 
492 /* Create a POSIX.1b interval timer. */
493 static int do_timer_create(clockid_t which_clock, struct sigevent *event,
494 			   timer_t __user *created_timer_id)
495 {
496 	const struct k_clock *kc = clockid_to_kclock(which_clock);
497 	struct k_itimer *new_timer;
498 	int error, new_timer_id;
499 	int it_id_set = IT_ID_NOT_SET;
500 
501 	if (!kc)
502 		return -EINVAL;
503 	if (!kc->timer_create)
504 		return -EOPNOTSUPP;
505 
506 	new_timer = alloc_posix_timer();
507 	if (unlikely(!new_timer))
508 		return -EAGAIN;
509 
510 	spin_lock_init(&new_timer->it_lock);
511 	new_timer_id = posix_timer_add(new_timer);
512 	if (new_timer_id < 0) {
513 		error = new_timer_id;
514 		goto out;
515 	}
516 
517 	it_id_set = IT_ID_SET;
518 	new_timer->it_id = (timer_t) new_timer_id;
519 	new_timer->it_clock = which_clock;
520 	new_timer->kclock = kc;
521 	new_timer->it_overrun = -1;
522 
523 	if (event) {
524 		rcu_read_lock();
525 		new_timer->it_pid = get_pid(good_sigevent(event));
526 		rcu_read_unlock();
527 		if (!new_timer->it_pid) {
528 			error = -EINVAL;
529 			goto out;
530 		}
531 		new_timer->it_sigev_notify     = event->sigev_notify;
532 		new_timer->sigq->info.si_signo = event->sigev_signo;
533 		new_timer->sigq->info.si_value = event->sigev_value;
534 	} else {
535 		new_timer->it_sigev_notify     = SIGEV_SIGNAL;
536 		new_timer->sigq->info.si_signo = SIGALRM;
537 		memset(&new_timer->sigq->info.si_value, 0, sizeof(sigval_t));
538 		new_timer->sigq->info.si_value.sival_int = new_timer->it_id;
539 		new_timer->it_pid = get_pid(task_tgid(current));
540 	}
541 
542 	new_timer->sigq->info.si_tid   = new_timer->it_id;
543 	new_timer->sigq->info.si_code  = SI_TIMER;
544 
545 	if (copy_to_user(created_timer_id,
546 			 &new_timer_id, sizeof (new_timer_id))) {
547 		error = -EFAULT;
548 		goto out;
549 	}
550 
551 	error = kc->timer_create(new_timer);
552 	if (error)
553 		goto out;
554 
555 	spin_lock_irq(&current->sighand->siglock);
556 	new_timer->it_signal = current->signal;
557 	list_add(&new_timer->list, &current->signal->posix_timers);
558 	spin_unlock_irq(&current->sighand->siglock);
559 
560 	return 0;
561 	/*
562 	 * In the case of the timer belonging to another task, after
563 	 * the task is unlocked, the timer is owned by the other task
564 	 * and may cease to exist at any time.  Don't use or modify
565 	 * new_timer after the unlock call.
566 	 */
567 out:
568 	release_posix_timer(new_timer, it_id_set);
569 	return error;
570 }
571 
572 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
573 		struct sigevent __user *, timer_event_spec,
574 		timer_t __user *, created_timer_id)
575 {
576 	if (timer_event_spec) {
577 		sigevent_t event;
578 
579 		if (copy_from_user(&event, timer_event_spec, sizeof (event)))
580 			return -EFAULT;
581 		return do_timer_create(which_clock, &event, created_timer_id);
582 	}
583 	return do_timer_create(which_clock, NULL, created_timer_id);
584 }
585 
586 #ifdef CONFIG_COMPAT
587 COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock,
588 		       struct compat_sigevent __user *, timer_event_spec,
589 		       timer_t __user *, created_timer_id)
590 {
591 	if (timer_event_spec) {
592 		sigevent_t event;
593 
594 		if (get_compat_sigevent(&event, timer_event_spec))
595 			return -EFAULT;
596 		return do_timer_create(which_clock, &event, created_timer_id);
597 	}
598 	return do_timer_create(which_clock, NULL, created_timer_id);
599 }
600 #endif
601 
602 /*
603  * Locking issues: We need to protect the result of the id look up until
604  * we get the timer locked down so it is not deleted under us.  The
605  * removal is done under the idr spinlock so we use that here to bridge
606  * the find to the timer lock.  To avoid a dead lock, the timer id MUST
607  * be release with out holding the timer lock.
608  */
609 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
610 {
611 	struct k_itimer *timr;
612 
613 	/*
614 	 * timer_t could be any type >= int and we want to make sure any
615 	 * @timer_id outside positive int range fails lookup.
616 	 */
617 	if ((unsigned long long)timer_id > INT_MAX)
618 		return NULL;
619 
620 	rcu_read_lock();
621 	timr = posix_timer_by_id(timer_id);
622 	if (timr) {
623 		spin_lock_irqsave(&timr->it_lock, *flags);
624 		if (timr->it_signal == current->signal) {
625 			rcu_read_unlock();
626 			return timr;
627 		}
628 		spin_unlock_irqrestore(&timr->it_lock, *flags);
629 	}
630 	rcu_read_unlock();
631 
632 	return NULL;
633 }
634 
635 static ktime_t common_hrtimer_remaining(struct k_itimer *timr, ktime_t now)
636 {
637 	struct hrtimer *timer = &timr->it.real.timer;
638 
639 	return __hrtimer_expires_remaining_adjusted(timer, now);
640 }
641 
642 static int common_hrtimer_forward(struct k_itimer *timr, ktime_t now)
643 {
644 	struct hrtimer *timer = &timr->it.real.timer;
645 
646 	return (int)hrtimer_forward(timer, now, timr->it_interval);
647 }
648 
649 /*
650  * Get the time remaining on a POSIX.1b interval timer.  This function
651  * is ALWAYS called with spin_lock_irq on the timer, thus it must not
652  * mess with irq.
653  *
654  * We have a couple of messes to clean up here.  First there is the case
655  * of a timer that has a requeue pending.  These timers should appear to
656  * be in the timer list with an expiry as if we were to requeue them
657  * now.
658  *
659  * The second issue is the SIGEV_NONE timer which may be active but is
660  * not really ever put in the timer list (to save system resources).
661  * This timer may be expired, and if so, we will do it here.  Otherwise
662  * it is the same as a requeue pending timer WRT to what we should
663  * report.
664  */
665 void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
666 {
667 	const struct k_clock *kc = timr->kclock;
668 	ktime_t now, remaining, iv;
669 	struct timespec64 ts64;
670 	bool sig_none;
671 
672 	sig_none = (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE;
673 	iv = timr->it_interval;
674 
675 	/* interval timer ? */
676 	if (iv) {
677 		cur_setting->it_interval = ktime_to_timespec64(iv);
678 	} else if (!timr->it_active) {
679 		/*
680 		 * SIGEV_NONE oneshot timers are never queued. Check them
681 		 * below.
682 		 */
683 		if (!sig_none)
684 			return;
685 	}
686 
687 	/*
688 	 * The timespec64 based conversion is suboptimal, but it's not
689 	 * worth to implement yet another callback.
690 	 */
691 	kc->clock_get(timr->it_clock, &ts64);
692 	now = timespec64_to_ktime(ts64);
693 
694 	/*
695 	 * When a requeue is pending or this is a SIGEV_NONE timer move the
696 	 * expiry time forward by intervals, so expiry is > now.
697 	 */
698 	if (iv && (timr->it_requeue_pending & REQUEUE_PENDING || sig_none))
699 		timr->it_overrun += kc->timer_forward(timr, now);
700 
701 	remaining = kc->timer_remaining(timr, now);
702 	/* Return 0 only, when the timer is expired and not pending */
703 	if (remaining <= 0) {
704 		/*
705 		 * A single shot SIGEV_NONE timer must return 0, when
706 		 * it is expired !
707 		 */
708 		if (!sig_none)
709 			cur_setting->it_value.tv_nsec = 1;
710 	} else {
711 		cur_setting->it_value = ktime_to_timespec64(remaining);
712 	}
713 }
714 
715 /* Get the time remaining on a POSIX.1b interval timer. */
716 static int do_timer_gettime(timer_t timer_id,  struct itimerspec64 *setting)
717 {
718 	struct k_itimer *timr;
719 	const struct k_clock *kc;
720 	unsigned long flags;
721 	int ret = 0;
722 
723 	timr = lock_timer(timer_id, &flags);
724 	if (!timr)
725 		return -EINVAL;
726 
727 	memset(setting, 0, sizeof(*setting));
728 	kc = timr->kclock;
729 	if (WARN_ON_ONCE(!kc || !kc->timer_get))
730 		ret = -EINVAL;
731 	else
732 		kc->timer_get(timr, setting);
733 
734 	unlock_timer(timr, flags);
735 	return ret;
736 }
737 
738 /* Get the time remaining on a POSIX.1b interval timer. */
739 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
740 		struct itimerspec __user *, setting)
741 {
742 	struct itimerspec64 cur_setting;
743 
744 	int ret = do_timer_gettime(timer_id, &cur_setting);
745 	if (!ret) {
746 		if (put_itimerspec64(&cur_setting, setting))
747 			ret = -EFAULT;
748 	}
749 	return ret;
750 }
751 
752 #ifdef CONFIG_COMPAT
753 COMPAT_SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
754 		       struct compat_itimerspec __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_compat_itimerspec64(&cur_setting, setting))
761 			ret = -EFAULT;
762 	}
763 	return ret;
764 }
765 #endif
766 
767 /*
768  * Get the number of overruns of a POSIX.1b interval timer.  This is to
769  * be the overrun of the timer last delivered.  At the same time we are
770  * accumulating overruns on the next timer.  The overrun is frozen when
771  * the signal is delivered, either at the notify time (if the info block
772  * is not queued) or at the actual delivery time (as we are informed by
773  * the call back to posixtimer_rearm().  So all we need to do is
774  * to pick up the frozen overrun.
775  */
776 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
777 {
778 	struct k_itimer *timr;
779 	int overrun;
780 	unsigned long flags;
781 
782 	timr = lock_timer(timer_id, &flags);
783 	if (!timr)
784 		return -EINVAL;
785 
786 	overrun = timr->it_overrun_last;
787 	unlock_timer(timr, flags);
788 
789 	return overrun;
790 }
791 
792 static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
793 			       bool absolute, bool sigev_none)
794 {
795 	struct hrtimer *timer = &timr->it.real.timer;
796 	enum hrtimer_mode mode;
797 
798 	mode = absolute ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
799 	/*
800 	 * Posix magic: Relative CLOCK_REALTIME timers are not affected by
801 	 * clock modifications, so they become CLOCK_MONOTONIC based under the
802 	 * hood. See hrtimer_init(). Update timr->kclock, so the generic
803 	 * functions which use timr->kclock->clock_get() work.
804 	 *
805 	 * Note: it_clock stays unmodified, because the next timer_set() might
806 	 * use ABSTIME, so it needs to switch back.
807 	 */
808 	if (timr->it_clock == CLOCK_REALTIME)
809 		timr->kclock = absolute ? &clock_realtime : &clock_monotonic;
810 
811 	hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
812 	timr->it.real.timer.function = posix_timer_fn;
813 
814 	if (!absolute)
815 		expires = ktime_add_safe(expires, timer->base->get_time());
816 	hrtimer_set_expires(timer, expires);
817 
818 	if (!sigev_none)
819 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
820 }
821 
822 static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
823 {
824 	return hrtimer_try_to_cancel(&timr->it.real.timer);
825 }
826 
827 /* Set a POSIX.1b interval timer. */
828 int common_timer_set(struct k_itimer *timr, int flags,
829 		     struct itimerspec64 *new_setting,
830 		     struct itimerspec64 *old_setting)
831 {
832 	const struct k_clock *kc = timr->kclock;
833 	bool sigev_none;
834 	ktime_t expires;
835 
836 	if (old_setting)
837 		common_timer_get(timr, old_setting);
838 
839 	/* Prevent rearming by clearing the interval */
840 	timr->it_interval = 0;
841 	/*
842 	 * Careful here. On SMP systems the timer expiry function could be
843 	 * active and spinning on timr->it_lock.
844 	 */
845 	if (kc->timer_try_to_cancel(timr) < 0)
846 		return TIMER_RETRY;
847 
848 	timr->it_active = 0;
849 	timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
850 		~REQUEUE_PENDING;
851 	timr->it_overrun_last = 0;
852 
853 	/* Switch off the timer when it_value is zero */
854 	if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
855 		return 0;
856 
857 	timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
858 	expires = timespec64_to_ktime(new_setting->it_value);
859 	sigev_none = (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE;
860 
861 	kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);
862 	timr->it_active = !sigev_none;
863 	return 0;
864 }
865 
866 static int do_timer_settime(timer_t timer_id, int flags,
867 			    struct itimerspec64 *new_spec64,
868 			    struct itimerspec64 *old_spec64)
869 {
870 	const struct k_clock *kc;
871 	struct k_itimer *timr;
872 	unsigned long flag;
873 	int error = 0;
874 
875 	if (!timespec64_valid(&new_spec64->it_interval) ||
876 	    !timespec64_valid(&new_spec64->it_value))
877 		return -EINVAL;
878 
879 	if (old_spec64)
880 		memset(old_spec64, 0, sizeof(*old_spec64));
881 retry:
882 	timr = lock_timer(timer_id, &flag);
883 	if (!timr)
884 		return -EINVAL;
885 
886 	kc = timr->kclock;
887 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
888 		error = -EINVAL;
889 	else
890 		error = kc->timer_set(timr, flags, new_spec64, old_spec64);
891 
892 	unlock_timer(timr, flag);
893 	if (error == TIMER_RETRY) {
894 		old_spec64 = NULL;	// We already got the old time...
895 		goto retry;
896 	}
897 
898 	return error;
899 }
900 
901 /* Set a POSIX.1b interval timer */
902 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
903 		const struct itimerspec __user *, new_setting,
904 		struct itimerspec __user *, old_setting)
905 {
906 	struct itimerspec64 new_spec, old_spec;
907 	struct itimerspec64 *rtn = old_setting ? &old_spec : NULL;
908 	int error = 0;
909 
910 	if (!new_setting)
911 		return -EINVAL;
912 
913 	if (get_itimerspec64(&new_spec, new_setting))
914 		return -EFAULT;
915 
916 	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
917 	if (!error && old_setting) {
918 		if (put_itimerspec64(&old_spec, old_setting))
919 			error = -EFAULT;
920 	}
921 	return error;
922 }
923 
924 #ifdef CONFIG_COMPAT
925 COMPAT_SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
926 		       struct compat_itimerspec __user *, new,
927 		       struct compat_itimerspec __user *, old)
928 {
929 	struct itimerspec64 new_spec, old_spec;
930 	struct itimerspec64 *rtn = old ? &old_spec : NULL;
931 	int error = 0;
932 
933 	if (!new)
934 		return -EINVAL;
935 	if (get_compat_itimerspec64(&new_spec, new))
936 		return -EFAULT;
937 
938 	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
939 	if (!error && old) {
940 		if (put_compat_itimerspec64(&old_spec, old))
941 			error = -EFAULT;
942 	}
943 	return error;
944 }
945 #endif
946 
947 int common_timer_del(struct k_itimer *timer)
948 {
949 	const struct k_clock *kc = timer->kclock;
950 
951 	timer->it_interval = 0;
952 	if (kc->timer_try_to_cancel(timer) < 0)
953 		return TIMER_RETRY;
954 	timer->it_active = 0;
955 	return 0;
956 }
957 
958 static inline int timer_delete_hook(struct k_itimer *timer)
959 {
960 	const struct k_clock *kc = timer->kclock;
961 
962 	if (WARN_ON_ONCE(!kc || !kc->timer_del))
963 		return -EINVAL;
964 	return kc->timer_del(timer);
965 }
966 
967 /* Delete a POSIX.1b interval timer. */
968 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
969 {
970 	struct k_itimer *timer;
971 	unsigned long flags;
972 
973 retry_delete:
974 	timer = lock_timer(timer_id, &flags);
975 	if (!timer)
976 		return -EINVAL;
977 
978 	if (timer_delete_hook(timer) == TIMER_RETRY) {
979 		unlock_timer(timer, flags);
980 		goto retry_delete;
981 	}
982 
983 	spin_lock(&current->sighand->siglock);
984 	list_del(&timer->list);
985 	spin_unlock(&current->sighand->siglock);
986 	/*
987 	 * This keeps any tasks waiting on the spin lock from thinking
988 	 * they got something (see the lock code above).
989 	 */
990 	timer->it_signal = NULL;
991 
992 	unlock_timer(timer, flags);
993 	release_posix_timer(timer, IT_ID_SET);
994 	return 0;
995 }
996 
997 /*
998  * return timer owned by the process, used by exit_itimers
999  */
1000 static void itimer_delete(struct k_itimer *timer)
1001 {
1002 	unsigned long flags;
1003 
1004 retry_delete:
1005 	spin_lock_irqsave(&timer->it_lock, flags);
1006 
1007 	if (timer_delete_hook(timer) == TIMER_RETRY) {
1008 		unlock_timer(timer, flags);
1009 		goto retry_delete;
1010 	}
1011 	list_del(&timer->list);
1012 	/*
1013 	 * This keeps any tasks waiting on the spin lock from thinking
1014 	 * they got something (see the lock code above).
1015 	 */
1016 	timer->it_signal = NULL;
1017 
1018 	unlock_timer(timer, flags);
1019 	release_posix_timer(timer, IT_ID_SET);
1020 }
1021 
1022 /*
1023  * This is called by do_exit or de_thread, only when there are no more
1024  * references to the shared signal_struct.
1025  */
1026 void exit_itimers(struct signal_struct *sig)
1027 {
1028 	struct k_itimer *tmr;
1029 
1030 	while (!list_empty(&sig->posix_timers)) {
1031 		tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
1032 		itimer_delete(tmr);
1033 	}
1034 }
1035 
1036 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1037 		const struct timespec __user *, tp)
1038 {
1039 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1040 	struct timespec64 new_tp;
1041 
1042 	if (!kc || !kc->clock_set)
1043 		return -EINVAL;
1044 
1045 	if (get_timespec64(&new_tp, tp))
1046 		return -EFAULT;
1047 
1048 	return kc->clock_set(which_clock, &new_tp);
1049 }
1050 
1051 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1052 		struct timespec __user *,tp)
1053 {
1054 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1055 	struct timespec64 kernel_tp;
1056 	int error;
1057 
1058 	if (!kc)
1059 		return -EINVAL;
1060 
1061 	error = kc->clock_get(which_clock, &kernel_tp);
1062 
1063 	if (!error && put_timespec64(&kernel_tp, tp))
1064 		error = -EFAULT;
1065 
1066 	return error;
1067 }
1068 
1069 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1070 		struct timex __user *, utx)
1071 {
1072 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1073 	struct timex ktx;
1074 	int err;
1075 
1076 	if (!kc)
1077 		return -EINVAL;
1078 	if (!kc->clock_adj)
1079 		return -EOPNOTSUPP;
1080 
1081 	if (copy_from_user(&ktx, utx, sizeof(ktx)))
1082 		return -EFAULT;
1083 
1084 	err = kc->clock_adj(which_clock, &ktx);
1085 
1086 	if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1087 		return -EFAULT;
1088 
1089 	return err;
1090 }
1091 
1092 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1093 		struct timespec __user *, tp)
1094 {
1095 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1096 	struct timespec64 rtn_tp;
1097 	int error;
1098 
1099 	if (!kc)
1100 		return -EINVAL;
1101 
1102 	error = kc->clock_getres(which_clock, &rtn_tp);
1103 
1104 	if (!error && tp && put_timespec64(&rtn_tp, tp))
1105 		error = -EFAULT;
1106 
1107 	return error;
1108 }
1109 
1110 #ifdef CONFIG_COMPAT
1111 
1112 COMPAT_SYSCALL_DEFINE2(clock_settime, clockid_t, which_clock,
1113 		       struct compat_timespec __user *, tp)
1114 {
1115 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1116 	struct timespec64 ts;
1117 
1118 	if (!kc || !kc->clock_set)
1119 		return -EINVAL;
1120 
1121 	if (compat_get_timespec64(&ts, tp))
1122 		return -EFAULT;
1123 
1124 	return kc->clock_set(which_clock, &ts);
1125 }
1126 
1127 COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
1128 		       struct compat_timespec __user *, tp)
1129 {
1130 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1131 	struct timespec64 ts;
1132 	int err;
1133 
1134 	if (!kc)
1135 		return -EINVAL;
1136 
1137 	err = kc->clock_get(which_clock, &ts);
1138 
1139 	if (!err && compat_put_timespec64(&ts, tp))
1140 		err = -EFAULT;
1141 
1142 	return err;
1143 }
1144 
1145 COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
1146 		       struct compat_timex __user *, utp)
1147 {
1148 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1149 	struct timex ktx;
1150 	int err;
1151 
1152 	if (!kc)
1153 		return -EINVAL;
1154 	if (!kc->clock_adj)
1155 		return -EOPNOTSUPP;
1156 
1157 	err = compat_get_timex(&ktx, utp);
1158 	if (err)
1159 		return err;
1160 
1161 	err = kc->clock_adj(which_clock, &ktx);
1162 
1163 	if (err >= 0)
1164 		err = compat_put_timex(utp, &ktx);
1165 
1166 	return err;
1167 }
1168 
1169 COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
1170 		       struct compat_timespec __user *, tp)
1171 {
1172 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1173 	struct timespec64 ts;
1174 	int err;
1175 
1176 	if (!kc)
1177 		return -EINVAL;
1178 
1179 	err = kc->clock_getres(which_clock, &ts);
1180 	if (!err && tp && compat_put_timespec64(&ts, tp))
1181 		return -EFAULT;
1182 
1183 	return err;
1184 }
1185 
1186 #endif
1187 
1188 /*
1189  * nanosleep for monotonic and realtime clocks
1190  */
1191 static int common_nsleep(const clockid_t which_clock, int flags,
1192 			 const struct timespec64 *rqtp)
1193 {
1194 	return hrtimer_nanosleep(rqtp, flags & TIMER_ABSTIME ?
1195 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1196 				 which_clock);
1197 }
1198 
1199 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1200 		const struct timespec __user *, rqtp,
1201 		struct timespec __user *, rmtp)
1202 {
1203 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1204 	struct timespec64 t;
1205 
1206 	if (!kc)
1207 		return -EINVAL;
1208 	if (!kc->nsleep)
1209 		return -ENANOSLEEP_NOTSUP;
1210 
1211 	if (get_timespec64(&t, rqtp))
1212 		return -EFAULT;
1213 
1214 	if (!timespec64_valid(&t))
1215 		return -EINVAL;
1216 	if (flags & TIMER_ABSTIME)
1217 		rmtp = NULL;
1218 	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
1219 	current->restart_block.nanosleep.rmtp = rmtp;
1220 
1221 	return kc->nsleep(which_clock, flags, &t);
1222 }
1223 
1224 #ifdef CONFIG_COMPAT
1225 COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
1226 		       struct compat_timespec __user *, rqtp,
1227 		       struct compat_timespec __user *, rmtp)
1228 {
1229 	const struct k_clock *kc = clockid_to_kclock(which_clock);
1230 	struct timespec64 t;
1231 
1232 	if (!kc)
1233 		return -EINVAL;
1234 	if (!kc->nsleep)
1235 		return -ENANOSLEEP_NOTSUP;
1236 
1237 	if (compat_get_timespec64(&t, rqtp))
1238 		return -EFAULT;
1239 
1240 	if (!timespec64_valid(&t))
1241 		return -EINVAL;
1242 	if (flags & TIMER_ABSTIME)
1243 		rmtp = NULL;
1244 	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
1245 	current->restart_block.nanosleep.compat_rmtp = rmtp;
1246 
1247 	return kc->nsleep(which_clock, flags, &t);
1248 }
1249 #endif
1250 
1251 static const struct k_clock clock_realtime = {
1252 	.clock_getres		= posix_get_hrtimer_res,
1253 	.clock_get		= posix_clock_realtime_get,
1254 	.clock_set		= posix_clock_realtime_set,
1255 	.clock_adj		= posix_clock_realtime_adj,
1256 	.nsleep			= common_nsleep,
1257 	.timer_create		= common_timer_create,
1258 	.timer_set		= common_timer_set,
1259 	.timer_get		= common_timer_get,
1260 	.timer_del		= common_timer_del,
1261 	.timer_rearm		= common_hrtimer_rearm,
1262 	.timer_forward		= common_hrtimer_forward,
1263 	.timer_remaining	= common_hrtimer_remaining,
1264 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1265 	.timer_arm		= common_hrtimer_arm,
1266 };
1267 
1268 static const struct k_clock clock_monotonic = {
1269 	.clock_getres		= posix_get_hrtimer_res,
1270 	.clock_get		= posix_ktime_get_ts,
1271 	.nsleep			= common_nsleep,
1272 	.timer_create		= common_timer_create,
1273 	.timer_set		= common_timer_set,
1274 	.timer_get		= common_timer_get,
1275 	.timer_del		= common_timer_del,
1276 	.timer_rearm		= common_hrtimer_rearm,
1277 	.timer_forward		= common_hrtimer_forward,
1278 	.timer_remaining	= common_hrtimer_remaining,
1279 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1280 	.timer_arm		= common_hrtimer_arm,
1281 };
1282 
1283 static const struct k_clock clock_monotonic_raw = {
1284 	.clock_getres		= posix_get_hrtimer_res,
1285 	.clock_get		= posix_get_monotonic_raw,
1286 };
1287 
1288 static const struct k_clock clock_realtime_coarse = {
1289 	.clock_getres		= posix_get_coarse_res,
1290 	.clock_get		= posix_get_realtime_coarse,
1291 };
1292 
1293 static const struct k_clock clock_monotonic_coarse = {
1294 	.clock_getres		= posix_get_coarse_res,
1295 	.clock_get		= posix_get_monotonic_coarse,
1296 };
1297 
1298 static const struct k_clock clock_tai = {
1299 	.clock_getres		= posix_get_hrtimer_res,
1300 	.clock_get		= posix_get_tai,
1301 	.nsleep			= common_nsleep,
1302 	.timer_create		= common_timer_create,
1303 	.timer_set		= common_timer_set,
1304 	.timer_get		= common_timer_get,
1305 	.timer_del		= common_timer_del,
1306 	.timer_rearm		= common_hrtimer_rearm,
1307 	.timer_forward		= common_hrtimer_forward,
1308 	.timer_remaining	= common_hrtimer_remaining,
1309 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1310 	.timer_arm		= common_hrtimer_arm,
1311 };
1312 
1313 static const struct k_clock clock_boottime = {
1314 	.clock_getres		= posix_get_hrtimer_res,
1315 	.clock_get		= posix_get_boottime,
1316 	.nsleep			= common_nsleep,
1317 	.timer_create		= common_timer_create,
1318 	.timer_set		= common_timer_set,
1319 	.timer_get		= common_timer_get,
1320 	.timer_del		= common_timer_del,
1321 	.timer_rearm		= common_hrtimer_rearm,
1322 	.timer_forward		= common_hrtimer_forward,
1323 	.timer_remaining	= common_hrtimer_remaining,
1324 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
1325 	.timer_arm		= common_hrtimer_arm,
1326 };
1327 
1328 static const struct k_clock * const posix_clocks[] = {
1329 	[CLOCK_REALTIME]		= &clock_realtime,
1330 	[CLOCK_MONOTONIC]		= &clock_monotonic,
1331 	[CLOCK_PROCESS_CPUTIME_ID]	= &clock_process,
1332 	[CLOCK_THREAD_CPUTIME_ID]	= &clock_thread,
1333 	[CLOCK_MONOTONIC_RAW]		= &clock_monotonic_raw,
1334 	[CLOCK_REALTIME_COARSE]		= &clock_realtime_coarse,
1335 	[CLOCK_MONOTONIC_COARSE]	= &clock_monotonic_coarse,
1336 	[CLOCK_BOOTTIME]		= &clock_boottime,
1337 	[CLOCK_REALTIME_ALARM]		= &alarm_clock,
1338 	[CLOCK_BOOTTIME_ALARM]		= &alarm_clock,
1339 	[CLOCK_TAI]			= &clock_tai,
1340 };
1341 
1342 static const struct k_clock *clockid_to_kclock(const clockid_t id)
1343 {
1344 	if (id < 0)
1345 		return (id & CLOCKFD_MASK) == CLOCKFD ?
1346 			&clock_posix_dynamic : &clock_posix_cpu;
1347 
1348 	if (id >= ARRAY_SIZE(posix_clocks) || !posix_clocks[id])
1349 		return NULL;
1350 	return posix_clocks[id];
1351 }
1352