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Linux/kernel/time/posix-timers.c

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  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 
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 
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 
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 
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 
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 */
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 
176 static ktime_t posix_get_realtime_ktime(clockid_t which_clock)
177 {
178         return ktime_get_real();
179 }
180 
181 /* Set clock_realtime */
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 
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  */
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 
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  */
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 
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 
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 
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 
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 
247 static ktime_t posix_get_boottime_ktime(const clockid_t which_clock)
248 {
249         return ktime_get_boottime();
250 }
251 
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 
258 static ktime_t posix_get_tai_ktime(clockid_t which_clock)
259 {
260         return ktime_get_clocktai();
261 }
262 
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  */
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, SLAB_PANIC,
277                                         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  */
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 
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  */
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 
336 int posix_timer_event(struct k_itimer *timr, int si_private)
337 {
338         enum pid_type type;
339         int ret = -1;
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  */
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 
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                 /* FALLTHRU */
443         case SIGEV_SIGNAL:
444         case SIGEV_THREAD:
445                 if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX)
446                         return NULL;
447                 /* FALLTHRU */
448         case SIGEV_NONE:
449                 return pid;
450         default:
451                 return NULL;
452         }
453 }
454 
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 
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
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 
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. */
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 
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
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  */
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 
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 
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  */
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. */
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. */
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 
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  */
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 
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 
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 
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  */
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. */
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 
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 */
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
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 
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 
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. */
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  */
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 there are no more
1055  * references to the shared signal_struct.
1056  */
1057 void exit_itimers(struct signal_struct *sig)
1058 {
1059         struct k_itimer *tmr;
1060 
1061         while (!list_empty(&sig->posix_timers)) {
1062                 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
1063                 itimer_delete(tmr);
1064         }
1065 }
1066 
1067 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1068                 const struct __kernel_timespec __user *, tp)
1069 {
1070         const struct k_clock *kc = clockid_to_kclock(which_clock);
1071         struct timespec64 new_tp;
1072 
1073         if (!kc || !kc->clock_set)
1074                 return -EINVAL;
1075 
1076         if (get_timespec64(&new_tp, tp))
1077                 return -EFAULT;
1078 
1079         return kc->clock_set(which_clock, &new_tp);
1080 }
1081 
1082 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1083                 struct __kernel_timespec __user *, tp)
1084 {
1085         const struct k_clock *kc = clockid_to_kclock(which_clock);
1086         struct timespec64 kernel_tp;
1087         int error;
1088 
1089         if (!kc)
1090                 return -EINVAL;
1091 
1092         error = kc->clock_get_timespec(which_clock, &kernel_tp);
1093 
1094         if (!error && put_timespec64(&kernel_tp, tp))
1095                 error = -EFAULT;
1096 
1097         return error;
1098 }
1099 
1100 int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * ktx)
1101 {
1102         const struct k_clock *kc = clockid_to_kclock(which_clock);
1103 
1104         if (!kc)
1105                 return -EINVAL;
1106         if (!kc->clock_adj)
1107                 return -EOPNOTSUPP;
1108 
1109         return kc->clock_adj(which_clock, ktx);
1110 }
1111 
1112 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1113                 struct __kernel_timex __user *, utx)
1114 {
1115         struct __kernel_timex ktx;
1116         int err;
1117 
1118         if (copy_from_user(&ktx, utx, sizeof(ktx)))
1119                 return -EFAULT;
1120 
1121         err = do_clock_adjtime(which_clock, &ktx);
1122 
1123         if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1124                 return -EFAULT;
1125 
1126         return err;
1127 }
1128 
1129 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1130                 struct __kernel_timespec __user *, tp)
1131 {
1132         const struct k_clock *kc = clockid_to_kclock(which_clock);
1133         struct timespec64 rtn_tp;
1134         int error;
1135 
1136         if (!kc)
1137                 return -EINVAL;
1138 
1139         error = kc->clock_getres(which_clock, &rtn_tp);
1140 
1141         if (!error && tp && put_timespec64(&rtn_tp, tp))
1142                 error = -EFAULT;
1143 
1144         return error;
1145 }
1146 
1147 #ifdef CONFIG_COMPAT_32BIT_TIME
1148 
1149 SYSCALL_DEFINE2(clock_settime32, clockid_t, which_clock,
1150                 struct old_timespec32 __user *, tp)
1151 {
1152         const struct k_clock *kc = clockid_to_kclock(which_clock);
1153         struct timespec64 ts;
1154 
1155         if (!kc || !kc->clock_set)
1156                 return -EINVAL;
1157 
1158         if (get_old_timespec32(&ts, tp))
1159                 return -EFAULT;
1160 
1161         return kc->clock_set(which_clock, &ts);
1162 }
1163 
1164 SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
1165                 struct old_timespec32 __user *, tp)
1166 {
1167         const struct k_clock *kc = clockid_to_kclock(which_clock);
1168         struct timespec64 ts;
1169         int err;
1170 
1171         if (!kc)
1172                 return -EINVAL;
1173 
1174         err = kc->clock_get_timespec(which_clock, &ts);
1175 
1176         if (!err && put_old_timespec32(&ts, tp))
1177                 err = -EFAULT;
1178 
1179         return err;
1180 }
1181 
1182 SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
1183                 struct old_timex32 __user *, utp)
1184 {
1185         struct __kernel_timex ktx;
1186         int err;
1187 
1188         err = get_old_timex32(&ktx, utp);
1189         if (err)
1190                 return err;
1191 
1192         err = do_clock_adjtime(which_clock, &ktx);
1193 
1194         if (err >= 0)
1195                 err = put_old_timex32(utp, &ktx);
1196 
1197         return err;
1198 }
1199 
1200 SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
1201                 struct old_timespec32 __user *, tp)
1202 {
1203         const struct k_clock *kc = clockid_to_kclock(which_clock);
1204         struct timespec64 ts;
1205         int err;
1206 
1207         if (!kc)
1208                 return -EINVAL;
1209 
1210         err = kc->clock_getres(which_clock, &ts);
1211         if (!err && tp && put_old_timespec32(&ts, tp))
1212                 return -EFAULT;
1213 
1214         return err;
1215 }
1216 
1217 #endif
1218 
1219 /*
1220  * nanosleep for monotonic and realtime clocks
1221  */
1222 static int common_nsleep(const clockid_t which_clock, int flags,
1223                          const struct timespec64 *rqtp)
1224 {
1225         ktime_t texp = timespec64_to_ktime(*rqtp);
1226 
1227         return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
1228                                  HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1229                                  which_clock);
1230 }
1231 
1232 static int common_nsleep_timens(const clockid_t which_clock, int flags,
1233                          const struct timespec64 *rqtp)
1234 {
1235         ktime_t texp = timespec64_to_ktime(*rqtp);
1236 
1237         if (flags & TIMER_ABSTIME)
1238                 texp = timens_ktime_to_host(which_clock, texp);
1239 
1240         return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
1241                                  HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1242                                  which_clock);
1243 }
1244 
1245 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1246                 const struct __kernel_timespec __user *, rqtp,
1247                 struct __kernel_timespec __user *, rmtp)
1248 {
1249         const struct k_clock *kc = clockid_to_kclock(which_clock);
1250         struct timespec64 t;
1251 
1252         if (!kc)
1253                 return -EINVAL;
1254         if (!kc->nsleep)
1255                 return -EOPNOTSUPP;
1256 
1257         if (get_timespec64(&t, rqtp))
1258                 return -EFAULT;
1259 
1260         if (!timespec64_valid(&t))
1261                 return -EINVAL;
1262         if (flags & TIMER_ABSTIME)
1263                 rmtp = NULL;
1264         current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
1265         current->restart_block.nanosleep.rmtp = rmtp;
1266 
1267         return kc->nsleep(which_clock, flags, &t);
1268 }
1269 
1270 #ifdef CONFIG_COMPAT_32BIT_TIME
1271 
1272 SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
1273                 struct old_timespec32 __user *, rqtp,
1274                 struct old_timespec32 __user *, rmtp)
1275 {
1276         const struct k_clock *kc = clockid_to_kclock(which_clock);
1277         struct timespec64 t;
1278 
1279         if (!kc)
1280                 return -EINVAL;
1281         if (!kc->nsleep)
1282                 return -EOPNOTSUPP;
1283 
1284         if (get_old_timespec32(&t, rqtp))
1285                 return -EFAULT;
1286 
1287         if (!timespec64_valid(&t))
1288                 return -EINVAL;
1289         if (flags & TIMER_ABSTIME)
1290                 rmtp = NULL;
1291         current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
1292         current->restart_block.nanosleep.compat_rmtp = rmtp;
1293 
1294         return kc->nsleep(which_clock, flags, &t);
1295 }
1296 
1297 #endif
1298 
1299 static const struct k_clock clock_realtime = {
1300         .clock_getres           = posix_get_hrtimer_res,
1301         .clock_get_timespec     = posix_get_realtime_timespec,
1302         .clock_get_ktime        = posix_get_realtime_ktime,
1303         .clock_set              = posix_clock_realtime_set,
1304         .clock_adj              = posix_clock_realtime_adj,
1305         .nsleep                 = common_nsleep,
1306         .timer_create           = common_timer_create,
1307         .timer_set              = common_timer_set,
1308         .timer_get              = common_timer_get,
1309         .timer_del              = common_timer_del,
1310         .timer_rearm            = common_hrtimer_rearm,
1311         .timer_forward          = common_hrtimer_forward,
1312         .timer_remaining        = common_hrtimer_remaining,
1313         .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
1314         .timer_wait_running     = common_timer_wait_running,
1315         .timer_arm              = common_hrtimer_arm,
1316 };
1317 
1318 static const struct k_clock clock_monotonic = {
1319         .clock_getres           = posix_get_hrtimer_res,
1320         .clock_get_timespec     = posix_get_monotonic_timespec,
1321         .clock_get_ktime        = posix_get_monotonic_ktime,
1322         .nsleep                 = common_nsleep_timens,
1323         .timer_create           = common_timer_create,
1324         .timer_set              = common_timer_set,
1325         .timer_get              = common_timer_get,
1326         .timer_del              = common_timer_del,
1327         .timer_rearm            = common_hrtimer_rearm,
1328         .timer_forward          = common_hrtimer_forward,
1329         .timer_remaining        = common_hrtimer_remaining,
1330         .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
1331         .timer_wait_running     = common_timer_wait_running,
1332         .timer_arm              = common_hrtimer_arm,
1333 };
1334 
1335 static const struct k_clock clock_monotonic_raw = {
1336         .clock_getres           = posix_get_hrtimer_res,
1337         .clock_get_timespec     = posix_get_monotonic_raw,
1338 };
1339 
1340 static const struct k_clock clock_realtime_coarse = {
1341         .clock_getres           = posix_get_coarse_res,
1342         .clock_get_timespec     = posix_get_realtime_coarse,
1343 };
1344 
1345 static const struct k_clock clock_monotonic_coarse = {
1346         .clock_getres           = posix_get_coarse_res,
1347         .clock_get_timespec     = posix_get_monotonic_coarse,
1348 };
1349 
1350 static const struct k_clock clock_tai = {
1351         .clock_getres           = posix_get_hrtimer_res,
1352         .clock_get_ktime        = posix_get_tai_ktime,
1353         .clock_get_timespec     = posix_get_tai_timespec,
1354         .nsleep                 = common_nsleep,
1355         .timer_create           = common_timer_create,
1356         .timer_set              = common_timer_set,
1357         .timer_get              = common_timer_get,
1358         .timer_del              = common_timer_del,
1359         .timer_rearm            = common_hrtimer_rearm,
1360         .timer_forward          = common_hrtimer_forward,
1361         .timer_remaining        = common_hrtimer_remaining,
1362         .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
1363         .timer_wait_running     = common_timer_wait_running,
1364         .timer_arm              = common_hrtimer_arm,
1365 };
1366 
1367 static const struct k_clock clock_boottime = {
1368         .clock_getres           = posix_get_hrtimer_res,
1369         .clock_get_ktime        = posix_get_boottime_ktime,
1370         .clock_get_timespec     = posix_get_boottime_timespec,
1371         .nsleep                 = common_nsleep_timens,
1372         .timer_create           = common_timer_create,
1373         .timer_set              = common_timer_set,
1374         .timer_get              = common_timer_get,
1375         .timer_del              = common_timer_del,
1376         .timer_rearm            = common_hrtimer_rearm,
1377         .timer_forward          = common_hrtimer_forward,
1378         .timer_remaining        = common_hrtimer_remaining,
1379         .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
1380         .timer_wait_running     = common_timer_wait_running,
1381         .timer_arm              = common_hrtimer_arm,
1382 };
1383 
1384 static const struct k_clock * const posix_clocks[] = {
1385         [CLOCK_REALTIME]                = &clock_realtime,
1386         [CLOCK_MONOTONIC]               = &clock_monotonic,
1387         [CLOCK_PROCESS_CPUTIME_ID]      = &clock_process,
1388         [CLOCK_THREAD_CPUTIME_ID]       = &clock_thread,
1389         [CLOCK_MONOTONIC_RAW]           = &clock_monotonic_raw,
1390         [CLOCK_REALTIME_COARSE]         = &clock_realtime_coarse,
1391         [CLOCK_MONOTONIC_COARSE]        = &clock_monotonic_coarse,
1392         [CLOCK_BOOTTIME]                = &clock_boottime,
1393         [CLOCK_REALTIME_ALARM]          = &alarm_clock,
1394         [CLOCK_BOOTTIME_ALARM]          = &alarm_clock,
1395         [CLOCK_TAI]                     = &clock_tai,
1396 };
1397 
1398 static const struct k_clock *clockid_to_kclock(const clockid_t id)
1399 {
1400         clockid_t idx = id;
1401 
1402         if (id < 0) {
1403                 return (id & CLOCKFD_MASK) == CLOCKFD ?
1404                         &clock_posix_dynamic : &clock_posix_cpu;
1405         }
1406 
1407         if (id >= ARRAY_SIZE(posix_clocks))
1408                 return NULL;
1409 
1410         return posix_clocks[array_index_nospec(idx, ARRAY_SIZE(posix_clocks))];
1411 }
1412 

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