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 	cpu_timer_sample_group(clock_idx, tsk, &now);
1193 
1194 	if (oldval) {
1195 		/*
1196 		 * We are setting itimer. The *oldval is absolute and we update
1197 		 * it to be relative, *newval argument is relative and we update
1198 		 * it to be absolute.
1199 		 */
1200 		if (*oldval) {
1201 			if (*oldval <= now) {
1202 				/* Just about to fire. */
1203 				*oldval = TICK_NSEC;
1204 			} else {
1205 				*oldval -= now;
1206 			}
1207 		}
1208 
1209 		if (!*newval)
1210 			return;
1211 		*newval += now;
1212 	}
1213 
1214 	/*
1215 	 * Update expiration cache if we are the earliest timer, or eventually
1216 	 * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1217 	 */
1218 	switch (clock_idx) {
1219 	case CPUCLOCK_PROF:
1220 		if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1221 			tsk->signal->cputime_expires.prof_exp = *newval;
1222 		break;
1223 	case CPUCLOCK_VIRT:
1224 		if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1225 			tsk->signal->cputime_expires.virt_exp = *newval;
1226 		break;
1227 	}
1228 
1229 	tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1230 }
1231 
1232 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1233 			    const struct timespec64 *rqtp)
1234 {
1235 	struct itimerspec64 it;
1236 	struct k_itimer timer;
1237 	u64 expires;
1238 	int error;
1239 
1240 	/*
1241 	 * Set up a temporary timer and then wait for it to go off.
1242 	 */
1243 	memset(&timer, 0, sizeof timer);
1244 	spin_lock_init(&timer.it_lock);
1245 	timer.it_clock = which_clock;
1246 	timer.it_overrun = -1;
1247 	error = posix_cpu_timer_create(&timer);
1248 	timer.it_process = current;
1249 	if (!error) {
1250 		static struct itimerspec64 zero_it;
1251 		struct restart_block *restart;
1252 
1253 		memset(&it, 0, sizeof(it));
1254 		it.it_value = *rqtp;
1255 
1256 		spin_lock_irq(&timer.it_lock);
1257 		error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1258 		if (error) {
1259 			spin_unlock_irq(&timer.it_lock);
1260 			return error;
1261 		}
1262 
1263 		while (!signal_pending(current)) {
1264 			if (timer.it.cpu.expires == 0) {
1265 				/*
1266 				 * Our timer fired and was reset, below
1267 				 * deletion can not fail.
1268 				 */
1269 				posix_cpu_timer_del(&timer);
1270 				spin_unlock_irq(&timer.it_lock);
1271 				return 0;
1272 			}
1273 
1274 			/*
1275 			 * Block until cpu_timer_fire (or a signal) wakes us.
1276 			 */
1277 			__set_current_state(TASK_INTERRUPTIBLE);
1278 			spin_unlock_irq(&timer.it_lock);
1279 			schedule();
1280 			spin_lock_irq(&timer.it_lock);
1281 		}
1282 
1283 		/*
1284 		 * We were interrupted by a signal.
1285 		 */
1286 		expires = timer.it.cpu.expires;
1287 		error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1288 		if (!error) {
1289 			/*
1290 			 * Timer is now unarmed, deletion can not fail.
1291 			 */
1292 			posix_cpu_timer_del(&timer);
1293 		}
1294 		spin_unlock_irq(&timer.it_lock);
1295 
1296 		while (error == TIMER_RETRY) {
1297 			/*
1298 			 * We need to handle case when timer was or is in the
1299 			 * middle of firing. In other cases we already freed
1300 			 * resources.
1301 			 */
1302 			spin_lock_irq(&timer.it_lock);
1303 			error = posix_cpu_timer_del(&timer);
1304 			spin_unlock_irq(&timer.it_lock);
1305 		}
1306 
1307 		if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1308 			/*
1309 			 * It actually did fire already.
1310 			 */
1311 			return 0;
1312 		}
1313 
1314 		error = -ERESTART_RESTARTBLOCK;
1315 		/*
1316 		 * Report back to the user the time still remaining.
1317 		 */
1318 		restart = &current->restart_block;
1319 		restart->nanosleep.expires = expires;
1320 		if (restart->nanosleep.type != TT_NONE)
1321 			error = nanosleep_copyout(restart, &it.it_value);
1322 	}
1323 
1324 	return error;
1325 }
1326 
1327 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1328 
1329 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1330 			    const struct timespec64 *rqtp)
1331 {
1332 	struct restart_block *restart_block = &current->restart_block;
1333 	int error;
1334 
1335 	/*
1336 	 * Diagnose required errors first.
1337 	 */
1338 	if (CPUCLOCK_PERTHREAD(which_clock) &&
1339 	    (CPUCLOCK_PID(which_clock) == 0 ||
1340 	     CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1341 		return -EINVAL;
1342 
1343 	error = do_cpu_nanosleep(which_clock, flags, rqtp);
1344 
1345 	if (error == -ERESTART_RESTARTBLOCK) {
1346 
1347 		if (flags & TIMER_ABSTIME)
1348 			return -ERESTARTNOHAND;
1349 
1350 		restart_block->fn = posix_cpu_nsleep_restart;
1351 		restart_block->nanosleep.clockid = which_clock;
1352 	}
1353 	return error;
1354 }
1355 
1356 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1357 {
1358 	clockid_t which_clock = restart_block->nanosleep.clockid;
1359 	struct timespec64 t;
1360 
1361 	t = ns_to_timespec64(restart_block->nanosleep.expires);
1362 
1363 	return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1364 }
1365 
1366 #define PROCESS_CLOCK	MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1367 #define THREAD_CLOCK	MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1368 
1369 static int process_cpu_clock_getres(const clockid_t which_clock,
1370 				    struct timespec64 *tp)
1371 {
1372 	return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1373 }
1374 static int process_cpu_clock_get(const clockid_t which_clock,
1375 				 struct timespec64 *tp)
1376 {
1377 	return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1378 }
1379 static int process_cpu_timer_create(struct k_itimer *timer)
1380 {
1381 	timer->it_clock = PROCESS_CLOCK;
1382 	return posix_cpu_timer_create(timer);
1383 }
1384 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1385 			      const struct timespec64 *rqtp)
1386 {
1387 	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1388 }
1389 static int thread_cpu_clock_getres(const clockid_t which_clock,
1390 				   struct timespec64 *tp)
1391 {
1392 	return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1393 }
1394 static int thread_cpu_clock_get(const clockid_t which_clock,
1395 				struct timespec64 *tp)
1396 {
1397 	return posix_cpu_clock_get(THREAD_CLOCK, tp);
1398 }
1399 static int thread_cpu_timer_create(struct k_itimer *timer)
1400 {
1401 	timer->it_clock = THREAD_CLOCK;
1402 	return posix_cpu_timer_create(timer);
1403 }
1404 
1405 const struct k_clock clock_posix_cpu = {
1406 	.clock_getres	= posix_cpu_clock_getres,
1407 	.clock_set	= posix_cpu_clock_set,
1408 	.clock_get	= posix_cpu_clock_get,
1409 	.timer_create	= posix_cpu_timer_create,
1410 	.nsleep		= posix_cpu_nsleep,
1411 	.timer_set	= posix_cpu_timer_set,
1412 	.timer_del	= posix_cpu_timer_del,
1413 	.timer_get	= posix_cpu_timer_get,
1414 	.timer_rearm	= posix_cpu_timer_rearm,
1415 };
1416 
1417 const struct k_clock clock_process = {
1418 	.clock_getres	= process_cpu_clock_getres,
1419 	.clock_get	= process_cpu_clock_get,
1420 	.timer_create	= process_cpu_timer_create,
1421 	.nsleep		= process_cpu_nsleep,
1422 };
1423 
1424 const struct k_clock clock_thread = {
1425 	.clock_getres	= thread_cpu_clock_getres,
1426 	.clock_get	= thread_cpu_clock_get,
1427 	.timer_create	= thread_cpu_timer_create,
1428 };
1429