ec9f5da6f163d40d3b2df9f4b9f76e783b304543
[sfrench/cifs-2.6.git] / kernel / time / posix-cpu-timers.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Implement CPU time clocks for the POSIX clock interface.
4  */
5
6 #include <linux/sched/signal.h>
7 #include <linux/sched/cputime.h>
8 #include <linux/posix-timers.h>
9 #include <linux/errno.h>
10 #include <linux/math64.h>
11 #include <linux/uaccess.h>
12 #include <linux/kernel_stat.h>
13 #include <trace/events/timer.h>
14 #include <linux/tick.h>
15 #include <linux/workqueue.h>
16 #include <linux/compat.h>
17
18 #include "posix-timers.h"
19
20 static void posix_cpu_timer_rearm(struct k_itimer *timer);
21
22 /*
23  * Called after updating RLIMIT_CPU to run cpu timer and update
24  * tsk->signal->cputime_expires expiration cache if necessary. Needs
25  * siglock protection since other code may update expiration cache as
26  * well.
27  */
28 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
29 {
30         u64 nsecs = rlim_new * NSEC_PER_SEC;
31
32         spin_lock_irq(&task->sighand->siglock);
33         set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
34         spin_unlock_irq(&task->sighand->siglock);
35 }
36
37 static int check_clock(const clockid_t which_clock)
38 {
39         int error = 0;
40         struct task_struct *p;
41         const pid_t pid = CPUCLOCK_PID(which_clock);
42
43         if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
44                 return -EINVAL;
45
46         if (pid == 0)
47                 return 0;
48
49         rcu_read_lock();
50         p = find_task_by_vpid(pid);
51         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
52                    same_thread_group(p, current) : has_group_leader_pid(p))) {
53                 error = -EINVAL;
54         }
55         rcu_read_unlock();
56
57         return error;
58 }
59
60 /*
61  * Update expiry time from increment, and increase overrun count,
62  * given the current clock sample.
63  */
64 static void bump_cpu_timer(struct k_itimer *timer, u64 now)
65 {
66         int i;
67         u64 delta, incr;
68
69         if (timer->it.cpu.incr == 0)
70                 return;
71
72         if (now < timer->it.cpu.expires)
73                 return;
74
75         incr = timer->it.cpu.incr;
76         delta = now + incr - timer->it.cpu.expires;
77
78         /* Don't use (incr*2 < delta), incr*2 might overflow. */
79         for (i = 0; incr < delta - incr; i++)
80                 incr = incr << 1;
81
82         for (; i >= 0; incr >>= 1, i--) {
83                 if (delta < incr)
84                         continue;
85
86                 timer->it.cpu.expires += incr;
87                 timer->it_overrun += 1 << i;
88                 delta -= incr;
89         }
90 }
91
92 /**
93  * task_cputime_zero - Check a task_cputime struct for all zero fields.
94  *
95  * @cputime:    The struct to compare.
96  *
97  * Checks @cputime to see if all fields are zero.  Returns true if all fields
98  * are zero, false if any field is nonzero.
99  */
100 static inline int task_cputime_zero(const struct task_cputime *cputime)
101 {
102         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
103                 return 1;
104         return 0;
105 }
106
107 static inline u64 prof_ticks(struct task_struct *p)
108 {
109         u64 utime, stime;
110
111         task_cputime(p, &utime, &stime);
112
113         return utime + stime;
114 }
115 static inline u64 virt_ticks(struct task_struct *p)
116 {
117         u64 utime, stime;
118
119         task_cputime(p, &utime, &stime);
120
121         return utime;
122 }
123
124 static int
125 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
126 {
127         int error = check_clock(which_clock);
128         if (!error) {
129                 tp->tv_sec = 0;
130                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
131                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
132                         /*
133                          * If sched_clock is using a cycle counter, we
134                          * don't have any idea of its true resolution
135                          * exported, but it is much more than 1s/HZ.
136                          */
137                         tp->tv_nsec = 1;
138                 }
139         }
140         return error;
141 }
142
143 static int
144 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec64 *tp)
145 {
146         /*
147          * You can never reset a CPU clock, but we check for other errors
148          * in the call before failing with EPERM.
149          */
150         int error = check_clock(which_clock);
151         if (error == 0) {
152                 error = -EPERM;
153         }
154         return error;
155 }
156
157
158 /*
159  * Sample a per-thread clock for the given task.
160  */
161 static int cpu_clock_sample(const clockid_t which_clock,
162                             struct task_struct *p, u64 *sample)
163 {
164         switch (CPUCLOCK_WHICH(which_clock)) {
165         default:
166                 return -EINVAL;
167         case CPUCLOCK_PROF:
168                 *sample = prof_ticks(p);
169                 break;
170         case CPUCLOCK_VIRT:
171                 *sample = virt_ticks(p);
172                 break;
173         case CPUCLOCK_SCHED:
174                 *sample = task_sched_runtime(p);
175                 break;
176         }
177         return 0;
178 }
179
180 /*
181  * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
182  * to avoid race conditions with concurrent updates to cputime.
183  */
184 static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
185 {
186         u64 curr_cputime;
187 retry:
188         curr_cputime = atomic64_read(cputime);
189         if (sum_cputime > curr_cputime) {
190                 if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
191                         goto retry;
192         }
193 }
194
195 static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
196 {
197         __update_gt_cputime(&cputime_atomic->utime, sum->utime);
198         __update_gt_cputime(&cputime_atomic->stime, sum->stime);
199         __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
200 }
201
202 /* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */
203 static inline void sample_cputime_atomic(struct task_cputime *times,
204                                          struct task_cputime_atomic *atomic_times)
205 {
206         times->utime = atomic64_read(&atomic_times->utime);
207         times->stime = atomic64_read(&atomic_times->stime);
208         times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime);
209 }
210
211 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
212 {
213         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
214         struct task_cputime sum;
215
216         /* Check if cputimer isn't running. This is accessed without locking. */
217         if (!READ_ONCE(cputimer->running)) {
218                 /*
219                  * The POSIX timer interface allows for absolute time expiry
220                  * values through the TIMER_ABSTIME flag, therefore we have
221                  * to synchronize the timer to the clock every time we start it.
222                  */
223                 thread_group_cputime(tsk, &sum);
224                 update_gt_cputime(&cputimer->cputime_atomic, &sum);
225
226                 /*
227                  * We're setting cputimer->running without a lock. Ensure
228                  * this only gets written to in one operation. We set
229                  * running after update_gt_cputime() as a small optimization,
230                  * but barriers are not required because update_gt_cputime()
231                  * can handle concurrent updates.
232                  */
233                 WRITE_ONCE(cputimer->running, true);
234         }
235         sample_cputime_atomic(times, &cputimer->cputime_atomic);
236 }
237
238 /*
239  * Sample a process (thread group) clock for the given group_leader task.
240  * Must be called with task sighand lock held for safe while_each_thread()
241  * traversal.
242  */
243 static int cpu_clock_sample_group(const clockid_t which_clock,
244                                   struct task_struct *p,
245                                   u64 *sample)
246 {
247         struct task_cputime cputime;
248
249         switch (CPUCLOCK_WHICH(which_clock)) {
250         default:
251                 return -EINVAL;
252         case CPUCLOCK_PROF:
253                 thread_group_cputime(p, &cputime);
254                 *sample = cputime.utime + cputime.stime;
255                 break;
256         case CPUCLOCK_VIRT:
257                 thread_group_cputime(p, &cputime);
258                 *sample = cputime.utime;
259                 break;
260         case CPUCLOCK_SCHED:
261                 thread_group_cputime(p, &cputime);
262                 *sample = cputime.sum_exec_runtime;
263                 break;
264         }
265         return 0;
266 }
267
268 static int posix_cpu_clock_get_task(struct task_struct *tsk,
269                                     const clockid_t which_clock,
270                                     struct timespec64 *tp)
271 {
272         int err = -EINVAL;
273         u64 rtn;
274
275         if (CPUCLOCK_PERTHREAD(which_clock)) {
276                 if (same_thread_group(tsk, current))
277                         err = cpu_clock_sample(which_clock, tsk, &rtn);
278         } else {
279                 if (tsk == current || thread_group_leader(tsk))
280                         err = cpu_clock_sample_group(which_clock, tsk, &rtn);
281         }
282
283         if (!err)
284                 *tp = ns_to_timespec64(rtn);
285
286         return err;
287 }
288
289
290 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec64 *tp)
291 {
292         const pid_t pid = CPUCLOCK_PID(which_clock);
293         int err = -EINVAL;
294
295         if (pid == 0) {
296                 /*
297                  * Special case constant value for our own clocks.
298                  * We don't have to do any lookup to find ourselves.
299                  */
300                 err = posix_cpu_clock_get_task(current, which_clock, tp);
301         } else {
302                 /*
303                  * Find the given PID, and validate that the caller
304                  * should be able to see it.
305                  */
306                 struct task_struct *p;
307                 rcu_read_lock();
308                 p = find_task_by_vpid(pid);
309                 if (p)
310                         err = posix_cpu_clock_get_task(p, which_clock, tp);
311                 rcu_read_unlock();
312         }
313
314         return err;
315 }
316
317 /*
318  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
319  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
320  * new timer already all-zeros initialized.
321  */
322 static int posix_cpu_timer_create(struct k_itimer *new_timer)
323 {
324         int ret = 0;
325         const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
326         struct task_struct *p;
327
328         if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
329                 return -EINVAL;
330
331         new_timer->kclock = &clock_posix_cpu;
332
333         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
334
335         rcu_read_lock();
336         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
337                 if (pid == 0) {
338                         p = current;
339                 } else {
340                         p = find_task_by_vpid(pid);
341                         if (p && !same_thread_group(p, current))
342                                 p = NULL;
343                 }
344         } else {
345                 if (pid == 0) {
346                         p = current->group_leader;
347                 } else {
348                         p = find_task_by_vpid(pid);
349                         if (p && !has_group_leader_pid(p))
350                                 p = NULL;
351                 }
352         }
353         new_timer->it.cpu.task = p;
354         if (p) {
355                 get_task_struct(p);
356         } else {
357                 ret = -EINVAL;
358         }
359         rcu_read_unlock();
360
361         return ret;
362 }
363
364 /*
365  * Clean up a CPU-clock timer that is about to be destroyed.
366  * This is called from timer deletion with the timer already locked.
367  * If we return TIMER_RETRY, it's necessary to release the timer's lock
368  * and try again.  (This happens when the timer is in the middle of firing.)
369  */
370 static int posix_cpu_timer_del(struct k_itimer *timer)
371 {
372         int ret = 0;
373         unsigned long flags;
374         struct sighand_struct *sighand;
375         struct task_struct *p = timer->it.cpu.task;
376
377         WARN_ON_ONCE(p == NULL);
378
379         /*
380          * Protect against sighand release/switch in exit/exec and process/
381          * thread timer list entry concurrent read/writes.
382          */
383         sighand = lock_task_sighand(p, &flags);
384         if (unlikely(sighand == NULL)) {
385                 /*
386                  * We raced with the reaping of the task.
387                  * The deletion should have cleared us off the list.
388                  */
389                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
390         } else {
391                 if (timer->it.cpu.firing)
392                         ret = TIMER_RETRY;
393                 else
394                         list_del(&timer->it.cpu.entry);
395
396                 unlock_task_sighand(p, &flags);
397         }
398
399         if (!ret)
400                 put_task_struct(p);
401
402         return ret;
403 }
404
405 static void cleanup_timers_list(struct list_head *head)
406 {
407         struct cpu_timer_list *timer, *next;
408
409         list_for_each_entry_safe(timer, next, head, entry)
410                 list_del_init(&timer->entry);
411 }
412
413 /*
414  * Clean out CPU timers still ticking when a thread exited.  The task
415  * pointer is cleared, and the expiry time is replaced with the residual
416  * time for later timer_gettime calls to return.
417  * This must be called with the siglock held.
418  */
419 static void cleanup_timers(struct list_head *head)
420 {
421         cleanup_timers_list(head);
422         cleanup_timers_list(++head);
423         cleanup_timers_list(++head);
424 }
425
426 /*
427  * These are both called with the siglock held, when the current thread
428  * is being reaped.  When the final (leader) thread in the group is reaped,
429  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
430  */
431 void posix_cpu_timers_exit(struct task_struct *tsk)
432 {
433         cleanup_timers(tsk->cpu_timers);
434 }
435 void posix_cpu_timers_exit_group(struct task_struct *tsk)
436 {
437         cleanup_timers(tsk->signal->cpu_timers);
438 }
439
440 static inline int expires_gt(u64 expires, u64 new_exp)
441 {
442         return expires == 0 || expires > new_exp;
443 }
444
445 /*
446  * Insert the timer on the appropriate list before any timers that
447  * expire later.  This must be called with the sighand lock held.
448  */
449 static void arm_timer(struct k_itimer *timer)
450 {
451         struct task_struct *p = timer->it.cpu.task;
452         struct list_head *head, *listpos;
453         struct task_cputime *cputime_expires;
454         struct cpu_timer_list *const nt = &timer->it.cpu;
455         struct cpu_timer_list *next;
456
457         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
458                 head = p->cpu_timers;
459                 cputime_expires = &p->cputime_expires;
460         } else {
461                 head = p->signal->cpu_timers;
462                 cputime_expires = &p->signal->cputime_expires;
463         }
464         head += CPUCLOCK_WHICH(timer->it_clock);
465
466         listpos = head;
467         list_for_each_entry(next, head, entry) {
468                 if (nt->expires < next->expires)
469                         break;
470                 listpos = &next->entry;
471         }
472         list_add(&nt->entry, listpos);
473
474         if (listpos == head) {
475                 u64 exp = nt->expires;
476
477                 /*
478                  * We are the new earliest-expiring POSIX 1.b timer, hence
479                  * need to update expiration cache. Take into account that
480                  * for process timers we share expiration cache with itimers
481                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
482                  */
483
484                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
485                 case CPUCLOCK_PROF:
486                         if (expires_gt(cputime_expires->prof_exp, exp))
487                                 cputime_expires->prof_exp = exp;
488                         break;
489                 case CPUCLOCK_VIRT:
490                         if (expires_gt(cputime_expires->virt_exp, exp))
491                                 cputime_expires->virt_exp = exp;
492                         break;
493                 case CPUCLOCK_SCHED:
494                         if (expires_gt(cputime_expires->sched_exp, exp))
495                                 cputime_expires->sched_exp = exp;
496                         break;
497                 }
498                 if (CPUCLOCK_PERTHREAD(timer->it_clock))
499                         tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
500                 else
501                         tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
502         }
503 }
504
505 /*
506  * The timer is locked, fire it and arrange for its reload.
507  */
508 static void cpu_timer_fire(struct k_itimer *timer)
509 {
510         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
511                 /*
512                  * User don't want any signal.
513                  */
514                 timer->it.cpu.expires = 0;
515         } else if (unlikely(timer->sigq == NULL)) {
516                 /*
517                  * This a special case for clock_nanosleep,
518                  * not a normal timer from sys_timer_create.
519                  */
520                 wake_up_process(timer->it_process);
521                 timer->it.cpu.expires = 0;
522         } else if (timer->it.cpu.incr == 0) {
523                 /*
524                  * One-shot timer.  Clear it as soon as it's fired.
525                  */
526                 posix_timer_event(timer, 0);
527                 timer->it.cpu.expires = 0;
528         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
529                 /*
530                  * The signal did not get queued because the signal
531                  * was ignored, so we won't get any callback to
532                  * reload the timer.  But we need to keep it
533                  * ticking in case the signal is deliverable next time.
534                  */
535                 posix_cpu_timer_rearm(timer);
536                 ++timer->it_requeue_pending;
537         }
538 }
539
540 /*
541  * Sample a process (thread group) timer for the given group_leader task.
542  * Must be called with task sighand lock held for safe while_each_thread()
543  * traversal.
544  */
545 static int cpu_timer_sample_group(const clockid_t which_clock,
546                                   struct task_struct *p, u64 *sample)
547 {
548         struct task_cputime cputime;
549
550         thread_group_cputimer(p, &cputime);
551         switch (CPUCLOCK_WHICH(which_clock)) {
552         default:
553                 return -EINVAL;
554         case CPUCLOCK_PROF:
555                 *sample = cputime.utime + cputime.stime;
556                 break;
557         case CPUCLOCK_VIRT:
558                 *sample = cputime.utime;
559                 break;
560         case CPUCLOCK_SCHED:
561                 *sample = cputime.sum_exec_runtime;
562                 break;
563         }
564         return 0;
565 }
566
567 /*
568  * Guts of sys_timer_settime for CPU timers.
569  * This is called with the timer locked and interrupts disabled.
570  * If we return TIMER_RETRY, it's necessary to release the timer's lock
571  * and try again.  (This happens when the timer is in the middle of firing.)
572  */
573 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
574                                struct itimerspec64 *new, struct itimerspec64 *old)
575 {
576         unsigned long flags;
577         struct sighand_struct *sighand;
578         struct task_struct *p = timer->it.cpu.task;
579         u64 old_expires, new_expires, old_incr, val;
580         int ret;
581
582         WARN_ON_ONCE(p == NULL);
583
584         /*
585          * Use the to_ktime conversion because that clamps the maximum
586          * value to KTIME_MAX and avoid multiplication overflows.
587          */
588         new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
589
590         /*
591          * Protect against sighand release/switch in exit/exec and p->cpu_timers
592          * and p->signal->cpu_timers read/write in arm_timer()
593          */
594         sighand = lock_task_sighand(p, &flags);
595         /*
596          * If p has just been reaped, we can no
597          * longer get any information about it at all.
598          */
599         if (unlikely(sighand == NULL)) {
600                 return -ESRCH;
601         }
602
603         /*
604          * Disarm any old timer after extracting its expiry time.
605          */
606         lockdep_assert_irqs_disabled();
607
608         ret = 0;
609         old_incr = timer->it.cpu.incr;
610         old_expires = timer->it.cpu.expires;
611         if (unlikely(timer->it.cpu.firing)) {
612                 timer->it.cpu.firing = -1;
613                 ret = TIMER_RETRY;
614         } else
615                 list_del_init(&timer->it.cpu.entry);
616
617         /*
618          * We need to sample the current value to convert the new
619          * value from to relative and absolute, and to convert the
620          * old value from absolute to relative.  To set a process
621          * timer, we need a sample to balance the thread expiry
622          * times (in arm_timer).  With an absolute time, we must
623          * check if it's already passed.  In short, we need a sample.
624          */
625         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
626                 cpu_clock_sample(timer->it_clock, p, &val);
627         } else {
628                 cpu_timer_sample_group(timer->it_clock, p, &val);
629         }
630
631         if (old) {
632                 if (old_expires == 0) {
633                         old->it_value.tv_sec = 0;
634                         old->it_value.tv_nsec = 0;
635                 } else {
636                         /*
637                          * Update the timer in case it has
638                          * overrun already.  If it has,
639                          * we'll report it as having overrun
640                          * and with the next reloaded timer
641                          * already ticking, though we are
642                          * swallowing that pending
643                          * notification here to install the
644                          * new setting.
645                          */
646                         bump_cpu_timer(timer, val);
647                         if (val < timer->it.cpu.expires) {
648                                 old_expires = timer->it.cpu.expires - val;
649                                 old->it_value = ns_to_timespec64(old_expires);
650                         } else {
651                                 old->it_value.tv_nsec = 1;
652                                 old->it_value.tv_sec = 0;
653                         }
654                 }
655         }
656
657         if (unlikely(ret)) {
658                 /*
659                  * We are colliding with the timer actually firing.
660                  * Punt after filling in the timer's old value, and
661                  * disable this firing since we are already reporting
662                  * it as an overrun (thanks to bump_cpu_timer above).
663                  */
664                 unlock_task_sighand(p, &flags);
665                 goto out;
666         }
667
668         if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
669                 new_expires += val;
670         }
671
672         /*
673          * Install the new expiry time (or zero).
674          * For a timer with no notification action, we don't actually
675          * arm the timer (we'll just fake it for timer_gettime).
676          */
677         timer->it.cpu.expires = new_expires;
678         if (new_expires != 0 && val < new_expires) {
679                 arm_timer(timer);
680         }
681
682         unlock_task_sighand(p, &flags);
683         /*
684          * Install the new reload setting, and
685          * set up the signal and overrun bookkeeping.
686          */
687         timer->it.cpu.incr = timespec64_to_ns(&new->it_interval);
688
689         /*
690          * This acts as a modification timestamp for the timer,
691          * so any automatic reload attempt will punt on seeing
692          * that we have reset the timer manually.
693          */
694         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
695                 ~REQUEUE_PENDING;
696         timer->it_overrun_last = 0;
697         timer->it_overrun = -1;
698
699         if (new_expires != 0 && !(val < new_expires)) {
700                 /*
701                  * The designated time already passed, so we notify
702                  * immediately, even if the thread never runs to
703                  * accumulate more time on this clock.
704                  */
705                 cpu_timer_fire(timer);
706         }
707
708         ret = 0;
709  out:
710         if (old)
711                 old->it_interval = ns_to_timespec64(old_incr);
712
713         return ret;
714 }
715
716 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
717 {
718         u64 now;
719         struct task_struct *p = timer->it.cpu.task;
720
721         WARN_ON_ONCE(p == NULL);
722
723         /*
724          * Easy part: convert the reload time.
725          */
726         itp->it_interval = ns_to_timespec64(timer->it.cpu.incr);
727
728         if (!timer->it.cpu.expires)
729                 return;
730
731         /*
732          * Sample the clock to take the difference with the expiry time.
733          */
734         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
735                 cpu_clock_sample(timer->it_clock, p, &now);
736         } else {
737                 struct sighand_struct *sighand;
738                 unsigned long flags;
739
740                 /*
741                  * Protect against sighand release/switch in exit/exec and
742                  * also make timer sampling safe if it ends up calling
743                  * thread_group_cputime().
744                  */
745                 sighand = lock_task_sighand(p, &flags);
746                 if (unlikely(sighand == NULL)) {
747                         /*
748                          * The process has been reaped.
749                          * We can't even collect a sample any more.
750                          * Call the timer disarmed, nothing else to do.
751                          */
752                         timer->it.cpu.expires = 0;
753                         return;
754                 } else {
755                         cpu_timer_sample_group(timer->it_clock, p, &now);
756                         unlock_task_sighand(p, &flags);
757                 }
758         }
759
760         if (now < timer->it.cpu.expires) {
761                 itp->it_value = ns_to_timespec64(timer->it.cpu.expires - now);
762         } else {
763                 /*
764                  * The timer should have expired already, but the firing
765                  * hasn't taken place yet.  Say it's just about to expire.
766                  */
767                 itp->it_value.tv_nsec = 1;
768                 itp->it_value.tv_sec = 0;
769         }
770 }
771
772 static unsigned long long
773 check_timers_list(struct list_head *timers,
774                   struct list_head *firing,
775                   unsigned long long curr)
776 {
777         int maxfire = 20;
778
779         while (!list_empty(timers)) {
780                 struct cpu_timer_list *t;
781
782                 t = list_first_entry(timers, struct cpu_timer_list, entry);
783
784                 if (!--maxfire || curr < t->expires)
785                         return t->expires;
786
787                 t->firing = 1;
788                 list_move_tail(&t->entry, firing);
789         }
790
791         return 0;
792 }
793
794 /*
795  * Check for any per-thread CPU timers that have fired and move them off
796  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
797  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
798  */
799 static void check_thread_timers(struct task_struct *tsk,
800                                 struct list_head *firing)
801 {
802         struct list_head *timers = tsk->cpu_timers;
803         struct task_cputime *tsk_expires = &tsk->cputime_expires;
804         u64 expires;
805         unsigned long soft;
806
807         /*
808          * If cputime_expires is zero, then there are no active
809          * per thread CPU timers.
810          */
811         if (task_cputime_zero(&tsk->cputime_expires))
812                 return;
813
814         expires = check_timers_list(timers, firing, prof_ticks(tsk));
815         tsk_expires->prof_exp = expires;
816
817         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
818         tsk_expires->virt_exp = expires;
819
820         tsk_expires->sched_exp = check_timers_list(++timers, firing,
821                                                    tsk->se.sum_exec_runtime);
822
823         /*
824          * Check for the special case thread timers.
825          */
826         soft = task_rlimit(tsk, RLIMIT_RTTIME);
827         if (soft != RLIM_INFINITY) {
828                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
829
830                 if (hard != RLIM_INFINITY &&
831                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
832                         /*
833                          * At the hard limit, we just die.
834                          * No need to calculate anything else now.
835                          */
836                         if (print_fatal_signals) {
837                                 pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
838                                         tsk->comm, task_pid_nr(tsk));
839                         }
840                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
841                         return;
842                 }
843                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
844                         /*
845                          * At the soft limit, send a SIGXCPU every second.
846                          */
847                         if (soft < hard) {
848                                 soft += USEC_PER_SEC;
849                                 tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur =
850                                         soft;
851                         }
852                         if (print_fatal_signals) {
853                                 pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
854                                         tsk->comm, task_pid_nr(tsk));
855                         }
856                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
857                 }
858         }
859         if (task_cputime_zero(tsk_expires))
860                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
861 }
862
863 static inline void stop_process_timers(struct signal_struct *sig)
864 {
865         struct thread_group_cputimer *cputimer = &sig->cputimer;
866
867         /* Turn off cputimer->running. This is done without locking. */
868         WRITE_ONCE(cputimer->running, false);
869         tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
870 }
871
872 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
873                              u64 *expires, u64 cur_time, int signo)
874 {
875         if (!it->expires)
876                 return;
877
878         if (cur_time >= it->expires) {
879                 if (it->incr)
880                         it->expires += it->incr;
881                 else
882                         it->expires = 0;
883
884                 trace_itimer_expire(signo == SIGPROF ?
885                                     ITIMER_PROF : ITIMER_VIRTUAL,
886                                     tsk->signal->leader_pid, cur_time);
887                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
888         }
889
890         if (it->expires && (!*expires || it->expires < *expires))
891                 *expires = it->expires;
892 }
893
894 /*
895  * Check for any per-thread CPU timers that have fired and move them
896  * off the tsk->*_timers list onto the firing list.  Per-thread timers
897  * have already been taken off.
898  */
899 static void check_process_timers(struct task_struct *tsk,
900                                  struct list_head *firing)
901 {
902         struct signal_struct *const sig = tsk->signal;
903         u64 utime, ptime, virt_expires, prof_expires;
904         u64 sum_sched_runtime, sched_expires;
905         struct list_head *timers = sig->cpu_timers;
906         struct task_cputime cputime;
907         unsigned long soft;
908
909         /*
910          * If cputimer is not running, then there are no active
911          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
912          */
913         if (!READ_ONCE(tsk->signal->cputimer.running))
914                 return;
915
916         /*
917          * Signify that a thread is checking for process timers.
918          * Write access to this field is protected by the sighand lock.
919          */
920         sig->cputimer.checking_timer = true;
921
922         /*
923          * Collect the current process totals.
924          */
925         thread_group_cputimer(tsk, &cputime);
926         utime = cputime.utime;
927         ptime = utime + cputime.stime;
928         sum_sched_runtime = cputime.sum_exec_runtime;
929
930         prof_expires = check_timers_list(timers, firing, ptime);
931         virt_expires = check_timers_list(++timers, firing, utime);
932         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
933
934         /*
935          * Check for the special case process timers.
936          */
937         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
938                          SIGPROF);
939         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
940                          SIGVTALRM);
941         soft = task_rlimit(tsk, RLIMIT_CPU);
942         if (soft != RLIM_INFINITY) {
943                 unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
944                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
945                 u64 x;
946                 if (psecs >= hard) {
947                         /*
948                          * At the hard limit, we just die.
949                          * No need to calculate anything else now.
950                          */
951                         if (print_fatal_signals) {
952                                 pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
953                                         tsk->comm, task_pid_nr(tsk));
954                         }
955                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
956                         return;
957                 }
958                 if (psecs >= soft) {
959                         /*
960                          * At the soft limit, send a SIGXCPU every second.
961                          */
962                         if (print_fatal_signals) {
963                                 pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
964                                         tsk->comm, task_pid_nr(tsk));
965                         }
966                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
967                         if (soft < hard) {
968                                 soft++;
969                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
970                         }
971                 }
972                 x = soft * NSEC_PER_SEC;
973                 if (!prof_expires || x < prof_expires)
974                         prof_expires = x;
975         }
976
977         sig->cputime_expires.prof_exp = prof_expires;
978         sig->cputime_expires.virt_exp = virt_expires;
979         sig->cputime_expires.sched_exp = sched_expires;
980         if (task_cputime_zero(&sig->cputime_expires))
981                 stop_process_timers(sig);
982
983         sig->cputimer.checking_timer = false;
984 }
985
986 /*
987  * This is called from the signal code (via posixtimer_rearm)
988  * when the last timer signal was delivered and we have to reload the timer.
989  */
990 static void posix_cpu_timer_rearm(struct k_itimer *timer)
991 {
992         struct sighand_struct *sighand;
993         unsigned long flags;
994         struct task_struct *p = timer->it.cpu.task;
995         u64 now;
996
997         WARN_ON_ONCE(p == NULL);
998
999         /*
1000          * Fetch the current sample and update the timer's expiry time.
1001          */
1002         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1003                 cpu_clock_sample(timer->it_clock, p, &now);
1004                 bump_cpu_timer(timer, now);
1005                 if (unlikely(p->exit_state))
1006                         return;
1007
1008                 /* Protect timer list r/w in arm_timer() */
1009                 sighand = lock_task_sighand(p, &flags);
1010                 if (!sighand)
1011                         return;
1012         } else {
1013                 /*
1014                  * Protect arm_timer() and timer sampling in case of call to
1015                  * thread_group_cputime().
1016                  */
1017                 sighand = lock_task_sighand(p, &flags);
1018                 if (unlikely(sighand == NULL)) {
1019                         /*
1020                          * The process has been reaped.
1021                          * We can't even collect a sample any more.
1022                          */
1023                         timer->it.cpu.expires = 0;
1024                         return;
1025                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1026                         /* If the process is dying, no need to rearm */
1027                         goto unlock;
1028                 }
1029                 cpu_timer_sample_group(timer->it_clock, p, &now);
1030                 bump_cpu_timer(timer, now);
1031                 /* Leave the sighand locked for the call below.  */
1032         }
1033
1034         /*
1035          * Now re-arm for the new expiry time.
1036          */
1037         lockdep_assert_irqs_disabled();
1038         arm_timer(timer);
1039 unlock:
1040         unlock_task_sighand(p, &flags);
1041 }
1042
1043 /**
1044  * task_cputime_expired - Compare two task_cputime entities.
1045  *
1046  * @sample:     The task_cputime structure to be checked for expiration.
1047  * @expires:    Expiration times, against which @sample will be checked.
1048  *
1049  * Checks @sample against @expires to see if any field of @sample has expired.
1050  * Returns true if any field of the former is greater than the corresponding
1051  * field of the latter if the latter field is set.  Otherwise returns false.
1052  */
1053 static inline int task_cputime_expired(const struct task_cputime *sample,
1054                                         const struct task_cputime *expires)
1055 {
1056         if (expires->utime && sample->utime >= expires->utime)
1057                 return 1;
1058         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1059                 return 1;
1060         if (expires->sum_exec_runtime != 0 &&
1061             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1062                 return 1;
1063         return 0;
1064 }
1065
1066 /**
1067  * fastpath_timer_check - POSIX CPU timers fast path.
1068  *
1069  * @tsk:        The task (thread) being checked.
1070  *
1071  * Check the task and thread group timers.  If both are zero (there are no
1072  * timers set) return false.  Otherwise snapshot the task and thread group
1073  * timers and compare them with the corresponding expiration times.  Return
1074  * true if a timer has expired, else return false.
1075  */
1076 static inline int fastpath_timer_check(struct task_struct *tsk)
1077 {
1078         struct signal_struct *sig;
1079
1080         if (!task_cputime_zero(&tsk->cputime_expires)) {
1081                 struct task_cputime task_sample;
1082
1083                 task_cputime(tsk, &task_sample.utime, &task_sample.stime);
1084                 task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
1085                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1086                         return 1;
1087         }
1088
1089         sig = tsk->signal;
1090         /*
1091          * Check if thread group timers expired when the cputimer is
1092          * running and no other thread in the group is already checking
1093          * for thread group cputimers. These fields are read without the
1094          * sighand lock. However, this is fine because this is meant to
1095          * be a fastpath heuristic to determine whether we should try to
1096          * acquire the sighand lock to check/handle timers.
1097          *
1098          * In the worst case scenario, if 'running' or 'checking_timer' gets
1099          * set but the current thread doesn't see the change yet, we'll wait
1100          * until the next thread in the group gets a scheduler interrupt to
1101          * handle the timer. This isn't an issue in practice because these
1102          * types of delays with signals actually getting sent are expected.
1103          */
1104         if (READ_ONCE(sig->cputimer.running) &&
1105             !READ_ONCE(sig->cputimer.checking_timer)) {
1106                 struct task_cputime group_sample;
1107
1108                 sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
1109
1110                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1111                         return 1;
1112         }
1113
1114         return 0;
1115 }
1116
1117 /*
1118  * This is called from the timer interrupt handler.  The irq handler has
1119  * already updated our counts.  We need to check if any timers fire now.
1120  * Interrupts are disabled.
1121  */
1122 void run_posix_cpu_timers(struct task_struct *tsk)
1123 {
1124         LIST_HEAD(firing);
1125         struct k_itimer *timer, *next;
1126         unsigned long flags;
1127
1128         lockdep_assert_irqs_disabled();
1129
1130         /*
1131          * The fast path checks that there are no expired thread or thread
1132          * group timers.  If that's so, just return.
1133          */
1134         if (!fastpath_timer_check(tsk))
1135                 return;
1136
1137         if (!lock_task_sighand(tsk, &flags))
1138                 return;
1139         /*
1140          * Here we take off tsk->signal->cpu_timers[N] and
1141          * tsk->cpu_timers[N] all the timers that are firing, and
1142          * put them on the firing list.
1143          */
1144         check_thread_timers(tsk, &firing);
1145
1146         check_process_timers(tsk, &firing);
1147
1148         /*
1149          * We must release these locks before taking any timer's lock.
1150          * There is a potential race with timer deletion here, as the
1151          * siglock now protects our private firing list.  We have set
1152          * the firing flag in each timer, so that a deletion attempt
1153          * that gets the timer lock before we do will give it up and
1154          * spin until we've taken care of that timer below.
1155          */
1156         unlock_task_sighand(tsk, &flags);
1157
1158         /*
1159          * Now that all the timers on our list have the firing flag,
1160          * no one will touch their list entries but us.  We'll take
1161          * each timer's lock before clearing its firing flag, so no
1162          * timer call will interfere.
1163          */
1164         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1165                 int cpu_firing;
1166
1167                 spin_lock(&timer->it_lock);
1168                 list_del_init(&timer->it.cpu.entry);
1169                 cpu_firing = timer->it.cpu.firing;
1170                 timer->it.cpu.firing = 0;
1171                 /*
1172                  * The firing flag is -1 if we collided with a reset
1173                  * of the timer, which already reported this
1174                  * almost-firing as an overrun.  So don't generate an event.
1175                  */
1176                 if (likely(cpu_firing >= 0))
1177                         cpu_timer_fire(timer);
1178                 spin_unlock(&timer->it_lock);
1179         }
1180 }
1181
1182 /*
1183  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1184  * The tsk->sighand->siglock must be held by the caller.
1185  */
1186 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1187                            u64 *newval, u64 *oldval)
1188 {
1189         u64 now;
1190
1191         WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
1192
1193         if (oldval && cpu_timer_sample_group(clock_idx, tsk, &now) != -EINVAL) {
1194                 /*
1195                  * We are setting itimer. The *oldval is absolute and we update
1196                  * it to be relative, *newval argument is relative and we update
1197                  * it to be absolute.
1198                  */
1199                 if (*oldval) {
1200                         if (*oldval <= now) {
1201                                 /* Just about to fire. */
1202                                 *oldval = TICK_NSEC;
1203                         } else {
1204                                 *oldval -= now;
1205                         }
1206                 }
1207
1208                 if (!*newval)
1209                         return;
1210                 *newval += now;
1211         }
1212
1213         /*
1214          * Update expiration cache if we are the earliest timer, or eventually
1215          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1216          */
1217         switch (clock_idx) {
1218         case CPUCLOCK_PROF:
1219                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1220                         tsk->signal->cputime_expires.prof_exp = *newval;
1221                 break;
1222         case CPUCLOCK_VIRT:
1223                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1224                         tsk->signal->cputime_expires.virt_exp = *newval;
1225                 break;
1226         }
1227
1228         tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1229 }
1230
1231 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1232                             const struct timespec64 *rqtp)
1233 {
1234         struct itimerspec64 it;
1235         struct k_itimer timer;
1236         u64 expires;
1237         int error;
1238
1239         /*
1240          * Set up a temporary timer and then wait for it to go off.
1241          */
1242         memset(&timer, 0, sizeof timer);
1243         spin_lock_init(&timer.it_lock);
1244         timer.it_clock = which_clock;
1245         timer.it_overrun = -1;
1246         error = posix_cpu_timer_create(&timer);
1247         timer.it_process = current;
1248         if (!error) {
1249                 static struct itimerspec64 zero_it;
1250                 struct restart_block *restart;
1251
1252                 memset(&it, 0, sizeof(it));
1253                 it.it_value = *rqtp;
1254
1255                 spin_lock_irq(&timer.it_lock);
1256                 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1257                 if (error) {
1258                         spin_unlock_irq(&timer.it_lock);
1259                         return error;
1260                 }
1261
1262                 while (!signal_pending(current)) {
1263                         if (timer.it.cpu.expires == 0) {
1264                                 /*
1265                                  * Our timer fired and was reset, below
1266                                  * deletion can not fail.
1267                                  */
1268                                 posix_cpu_timer_del(&timer);
1269                                 spin_unlock_irq(&timer.it_lock);
1270                                 return 0;
1271                         }
1272
1273                         /*
1274                          * Block until cpu_timer_fire (or a signal) wakes us.
1275                          */
1276                         __set_current_state(TASK_INTERRUPTIBLE);
1277                         spin_unlock_irq(&timer.it_lock);
1278                         schedule();
1279                         spin_lock_irq(&timer.it_lock);
1280                 }
1281
1282                 /*
1283                  * We were interrupted by a signal.
1284                  */
1285                 expires = timer.it.cpu.expires;
1286                 error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1287                 if (!error) {
1288                         /*
1289                          * Timer is now unarmed, deletion can not fail.
1290                          */
1291                         posix_cpu_timer_del(&timer);
1292                 }
1293                 spin_unlock_irq(&timer.it_lock);
1294
1295                 while (error == TIMER_RETRY) {
1296                         /*
1297                          * We need to handle case when timer was or is in the
1298                          * middle of firing. In other cases we already freed
1299                          * resources.
1300                          */
1301                         spin_lock_irq(&timer.it_lock);
1302                         error = posix_cpu_timer_del(&timer);
1303                         spin_unlock_irq(&timer.it_lock);
1304                 }
1305
1306                 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1307                         /*
1308                          * It actually did fire already.
1309                          */
1310                         return 0;
1311                 }
1312
1313                 error = -ERESTART_RESTARTBLOCK;
1314                 /*
1315                  * Report back to the user the time still remaining.
1316                  */
1317                 restart = &current->restart_block;
1318                 restart->nanosleep.expires = expires;
1319                 if (restart->nanosleep.type != TT_NONE)
1320                         error = nanosleep_copyout(restart, &it.it_value);
1321         }
1322
1323         return error;
1324 }
1325
1326 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1327
1328 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1329                             const struct timespec64 *rqtp)
1330 {
1331         struct restart_block *restart_block = &current->restart_block;
1332         int error;
1333
1334         /*
1335          * Diagnose required errors first.
1336          */
1337         if (CPUCLOCK_PERTHREAD(which_clock) &&
1338             (CPUCLOCK_PID(which_clock) == 0 ||
1339              CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1340                 return -EINVAL;
1341
1342         error = do_cpu_nanosleep(which_clock, flags, rqtp);
1343
1344         if (error == -ERESTART_RESTARTBLOCK) {
1345
1346                 if (flags & TIMER_ABSTIME)
1347                         return -ERESTARTNOHAND;
1348
1349                 restart_block->fn = posix_cpu_nsleep_restart;
1350                 restart_block->nanosleep.clockid = which_clock;
1351         }
1352         return error;
1353 }
1354
1355 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1356 {
1357         clockid_t which_clock = restart_block->nanosleep.clockid;
1358         struct timespec64 t;
1359
1360         t = ns_to_timespec64(restart_block->nanosleep.expires);
1361
1362         return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1363 }
1364
1365 #define PROCESS_CLOCK   make_process_cpuclock(0, CPUCLOCK_SCHED)
1366 #define THREAD_CLOCK    make_thread_cpuclock(0, CPUCLOCK_SCHED)
1367
1368 static int process_cpu_clock_getres(const clockid_t which_clock,
1369                                     struct timespec64 *tp)
1370 {
1371         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1372 }
1373 static int process_cpu_clock_get(const clockid_t which_clock,
1374                                  struct timespec64 *tp)
1375 {
1376         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1377 }
1378 static int process_cpu_timer_create(struct k_itimer *timer)
1379 {
1380         timer->it_clock = PROCESS_CLOCK;
1381         return posix_cpu_timer_create(timer);
1382 }
1383 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1384                               const struct timespec64 *rqtp)
1385 {
1386         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1387 }
1388 static int thread_cpu_clock_getres(const clockid_t which_clock,
1389                                    struct timespec64 *tp)
1390 {
1391         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1392 }
1393 static int thread_cpu_clock_get(const clockid_t which_clock,
1394                                 struct timespec64 *tp)
1395 {
1396         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1397 }
1398 static int thread_cpu_timer_create(struct k_itimer *timer)
1399 {
1400         timer->it_clock = THREAD_CLOCK;
1401         return posix_cpu_timer_create(timer);
1402 }
1403
1404 const struct k_clock clock_posix_cpu = {
1405         .clock_getres   = posix_cpu_clock_getres,
1406         .clock_set      = posix_cpu_clock_set,
1407         .clock_get      = posix_cpu_clock_get,
1408         .timer_create   = posix_cpu_timer_create,
1409         .nsleep         = posix_cpu_nsleep,
1410         .timer_set      = posix_cpu_timer_set,
1411         .timer_del      = posix_cpu_timer_del,
1412         .timer_get      = posix_cpu_timer_get,
1413         .timer_rearm    = posix_cpu_timer_rearm,
1414 };
1415
1416 const struct k_clock clock_process = {
1417         .clock_getres   = process_cpu_clock_getres,
1418         .clock_get      = process_cpu_clock_get,
1419         .timer_create   = process_cpu_timer_create,
1420         .nsleep         = process_cpu_nsleep,
1421 };
1422
1423 const struct k_clock clock_thread = {
1424         .clock_getres   = thread_cpu_clock_getres,
1425         .clock_get      = thread_cpu_clock_get,
1426         .timer_create   = thread_cpu_timer_create,
1427 };