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1/*
2 * Implement CPU time clocks for the POSIX clock interface.
3 */
4
5#include <linux/sched.h>
6#include <linux/posix-timers.h>
7#include <linux/errno.h>
8#include <linux/math64.h>
9#include <asm/uaccess.h>
10#include <linux/kernel_stat.h>
11#include <trace/events/timer.h>
12
13/*
14 * Called after updating RLIMIT_CPU to run cpu timer and update
15 * tsk->signal->cputime_expires expiration cache if necessary. Needs
16 * siglock protection since other code may update expiration cache as
17 * well.
18 */
19void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
20{
21 cputime_t cputime = secs_to_cputime(rlim_new);
22
23 spin_lock_irq(&task->sighand->siglock);
24 set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
25 spin_unlock_irq(&task->sighand->siglock);
26}
27
28static int check_clock(const clockid_t which_clock)
29{
30 int error = 0;
31 struct task_struct *p;
32 const pid_t pid = CPUCLOCK_PID(which_clock);
33
34 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
35 return -EINVAL;
36
37 if (pid == 0)
38 return 0;
39
40 rcu_read_lock();
41 p = find_task_by_vpid(pid);
42 if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
43 same_thread_group(p, current) : has_group_leader_pid(p))) {
44 error = -EINVAL;
45 }
46 rcu_read_unlock();
47
48 return error;
49}
50
51static inline union cpu_time_count
52timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
53{
54 union cpu_time_count ret;
55 ret.sched = 0; /* high half always zero when .cpu used */
56 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
57 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
58 } else {
59 ret.cpu = timespec_to_cputime(tp);
60 }
61 return ret;
62}
63
64static void sample_to_timespec(const clockid_t which_clock,
65 union cpu_time_count cpu,
66 struct timespec *tp)
67{
68 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
69 *tp = ns_to_timespec(cpu.sched);
70 else
71 cputime_to_timespec(cpu.cpu, tp);
72}
73
74static inline int cpu_time_before(const clockid_t which_clock,
75 union cpu_time_count now,
76 union cpu_time_count then)
77{
78 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
79 return now.sched < then.sched;
80 } else {
81 return now.cpu < then.cpu;
82 }
83}
84static inline void cpu_time_add(const clockid_t which_clock,
85 union cpu_time_count *acc,
86 union cpu_time_count val)
87{
88 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
89 acc->sched += val.sched;
90 } else {
91 acc->cpu += val.cpu;
92 }
93}
94static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
95 union cpu_time_count a,
96 union cpu_time_count b)
97{
98 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
99 a.sched -= b.sched;
100 } else {
101 a.cpu -= b.cpu;
102 }
103 return a;
104}
105
106/*
107 * Update expiry time from increment, and increase overrun count,
108 * given the current clock sample.
109 */
110static void bump_cpu_timer(struct k_itimer *timer,
111 union cpu_time_count now)
112{
113 int i;
114
115 if (timer->it.cpu.incr.sched == 0)
116 return;
117
118 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
119 unsigned long long delta, incr;
120
121 if (now.sched < timer->it.cpu.expires.sched)
122 return;
123 incr = timer->it.cpu.incr.sched;
124 delta = now.sched + incr - timer->it.cpu.expires.sched;
125 /* Don't use (incr*2 < delta), incr*2 might overflow. */
126 for (i = 0; incr < delta - incr; i++)
127 incr = incr << 1;
128 for (; i >= 0; incr >>= 1, i--) {
129 if (delta < incr)
130 continue;
131 timer->it.cpu.expires.sched += incr;
132 timer->it_overrun += 1 << i;
133 delta -= incr;
134 }
135 } else {
136 cputime_t delta, incr;
137
138 if (now.cpu < timer->it.cpu.expires.cpu)
139 return;
140 incr = timer->it.cpu.incr.cpu;
141 delta = now.cpu + incr - timer->it.cpu.expires.cpu;
142 /* Don't use (incr*2 < delta), incr*2 might overflow. */
143 for (i = 0; incr < delta - incr; i++)
144 incr += incr;
145 for (; i >= 0; incr = incr >> 1, i--) {
146 if (delta < incr)
147 continue;
148 timer->it.cpu.expires.cpu += incr;
149 timer->it_overrun += 1 << i;
150 delta -= incr;
151 }
152 }
153}
154
155static inline cputime_t prof_ticks(struct task_struct *p)
156{
157 return p->utime + p->stime;
158}
159static inline cputime_t virt_ticks(struct task_struct *p)
160{
161 return p->utime;
162}
163
164static int
165posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
166{
167 int error = check_clock(which_clock);
168 if (!error) {
169 tp->tv_sec = 0;
170 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
171 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
172 /*
173 * If sched_clock is using a cycle counter, we
174 * don't have any idea of its true resolution
175 * exported, but it is much more than 1s/HZ.
176 */
177 tp->tv_nsec = 1;
178 }
179 }
180 return error;
181}
182
183static int
184posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
185{
186 /*
187 * You can never reset a CPU clock, but we check for other errors
188 * in the call before failing with EPERM.
189 */
190 int error = check_clock(which_clock);
191 if (error == 0) {
192 error = -EPERM;
193 }
194 return error;
195}
196
197
198/*
199 * Sample a per-thread clock for the given task.
200 */
201static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
202 union cpu_time_count *cpu)
203{
204 switch (CPUCLOCK_WHICH(which_clock)) {
205 default:
206 return -EINVAL;
207 case CPUCLOCK_PROF:
208 cpu->cpu = prof_ticks(p);
209 break;
210 case CPUCLOCK_VIRT:
211 cpu->cpu = virt_ticks(p);
212 break;
213 case CPUCLOCK_SCHED:
214 cpu->sched = task_sched_runtime(p);
215 break;
216 }
217 return 0;
218}
219
220void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
221{
222 struct signal_struct *sig = tsk->signal;
223 struct task_struct *t;
224
225 times->utime = sig->utime;
226 times->stime = sig->stime;
227 times->sum_exec_runtime = sig->sum_sched_runtime;
228
229 rcu_read_lock();
230 /* make sure we can trust tsk->thread_group list */
231 if (!likely(pid_alive(tsk)))
232 goto out;
233
234 t = tsk;
235 do {
236 times->utime += t->utime;
237 times->stime += t->stime;
238 times->sum_exec_runtime += task_sched_runtime(t);
239 } while_each_thread(tsk, t);
240out:
241 rcu_read_unlock();
242}
243
244static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
245{
246 if (b->utime > a->utime)
247 a->utime = b->utime;
248
249 if (b->stime > a->stime)
250 a->stime = b->stime;
251
252 if (b->sum_exec_runtime > a->sum_exec_runtime)
253 a->sum_exec_runtime = b->sum_exec_runtime;
254}
255
256void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
257{
258 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
259 struct task_cputime sum;
260 unsigned long flags;
261
262 if (!cputimer->running) {
263 /*
264 * The POSIX timer interface allows for absolute time expiry
265 * values through the TIMER_ABSTIME flag, therefore we have
266 * to synchronize the timer to the clock every time we start
267 * it.
268 */
269 thread_group_cputime(tsk, &sum);
270 raw_spin_lock_irqsave(&cputimer->lock, flags);
271 cputimer->running = 1;
272 update_gt_cputime(&cputimer->cputime, &sum);
273 } else
274 raw_spin_lock_irqsave(&cputimer->lock, flags);
275 *times = cputimer->cputime;
276 raw_spin_unlock_irqrestore(&cputimer->lock, flags);
277}
278
279/*
280 * Sample a process (thread group) clock for the given group_leader task.
281 * Must be called with tasklist_lock held for reading.
282 */
283static int cpu_clock_sample_group(const clockid_t which_clock,
284 struct task_struct *p,
285 union cpu_time_count *cpu)
286{
287 struct task_cputime cputime;
288
289 switch (CPUCLOCK_WHICH(which_clock)) {
290 default:
291 return -EINVAL;
292 case CPUCLOCK_PROF:
293 thread_group_cputime(p, &cputime);
294 cpu->cpu = cputime.utime + cputime.stime;
295 break;
296 case CPUCLOCK_VIRT:
297 thread_group_cputime(p, &cputime);
298 cpu->cpu = cputime.utime;
299 break;
300 case CPUCLOCK_SCHED:
301 thread_group_cputime(p, &cputime);
302 cpu->sched = cputime.sum_exec_runtime;
303 break;
304 }
305 return 0;
306}
307
308
309static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
310{
311 const pid_t pid = CPUCLOCK_PID(which_clock);
312 int error = -EINVAL;
313 union cpu_time_count rtn;
314
315 if (pid == 0) {
316 /*
317 * Special case constant value for our own clocks.
318 * We don't have to do any lookup to find ourselves.
319 */
320 if (CPUCLOCK_PERTHREAD(which_clock)) {
321 /*
322 * Sampling just ourselves we can do with no locking.
323 */
324 error = cpu_clock_sample(which_clock,
325 current, &rtn);
326 } else {
327 read_lock(&tasklist_lock);
328 error = cpu_clock_sample_group(which_clock,
329 current, &rtn);
330 read_unlock(&tasklist_lock);
331 }
332 } else {
333 /*
334 * Find the given PID, and validate that the caller
335 * should be able to see it.
336 */
337 struct task_struct *p;
338 rcu_read_lock();
339 p = find_task_by_vpid(pid);
340 if (p) {
341 if (CPUCLOCK_PERTHREAD(which_clock)) {
342 if (same_thread_group(p, current)) {
343 error = cpu_clock_sample(which_clock,
344 p, &rtn);
345 }
346 } else {
347 read_lock(&tasklist_lock);
348 if (thread_group_leader(p) && p->sighand) {
349 error =
350 cpu_clock_sample_group(which_clock,
351 p, &rtn);
352 }
353 read_unlock(&tasklist_lock);
354 }
355 }
356 rcu_read_unlock();
357 }
358
359 if (error)
360 return error;
361 sample_to_timespec(which_clock, rtn, tp);
362 return 0;
363}
364
365
366/*
367 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
368 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
369 * new timer already all-zeros initialized.
370 */
371static int posix_cpu_timer_create(struct k_itimer *new_timer)
372{
373 int ret = 0;
374 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
375 struct task_struct *p;
376
377 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
378 return -EINVAL;
379
380 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
381
382 rcu_read_lock();
383 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
384 if (pid == 0) {
385 p = current;
386 } else {
387 p = find_task_by_vpid(pid);
388 if (p && !same_thread_group(p, current))
389 p = NULL;
390 }
391 } else {
392 if (pid == 0) {
393 p = current->group_leader;
394 } else {
395 p = find_task_by_vpid(pid);
396 if (p && !has_group_leader_pid(p))
397 p = NULL;
398 }
399 }
400 new_timer->it.cpu.task = p;
401 if (p) {
402 get_task_struct(p);
403 } else {
404 ret = -EINVAL;
405 }
406 rcu_read_unlock();
407
408 return ret;
409}
410
411/*
412 * Clean up a CPU-clock timer that is about to be destroyed.
413 * This is called from timer deletion with the timer already locked.
414 * If we return TIMER_RETRY, it's necessary to release the timer's lock
415 * and try again. (This happens when the timer is in the middle of firing.)
416 */
417static int posix_cpu_timer_del(struct k_itimer *timer)
418{
419 struct task_struct *p = timer->it.cpu.task;
420 int ret = 0;
421
422 if (likely(p != NULL)) {
423 read_lock(&tasklist_lock);
424 if (unlikely(p->sighand == NULL)) {
425 /*
426 * We raced with the reaping of the task.
427 * The deletion should have cleared us off the list.
428 */
429 BUG_ON(!list_empty(&timer->it.cpu.entry));
430 } else {
431 spin_lock(&p->sighand->siglock);
432 if (timer->it.cpu.firing)
433 ret = TIMER_RETRY;
434 else
435 list_del(&timer->it.cpu.entry);
436 spin_unlock(&p->sighand->siglock);
437 }
438 read_unlock(&tasklist_lock);
439
440 if (!ret)
441 put_task_struct(p);
442 }
443
444 return ret;
445}
446
447/*
448 * Clean out CPU timers still ticking when a thread exited. The task
449 * pointer is cleared, and the expiry time is replaced with the residual
450 * time for later timer_gettime calls to return.
451 * This must be called with the siglock held.
452 */
453static void cleanup_timers(struct list_head *head,
454 cputime_t utime, cputime_t stime,
455 unsigned long long sum_exec_runtime)
456{
457 struct cpu_timer_list *timer, *next;
458 cputime_t ptime = utime + stime;
459
460 list_for_each_entry_safe(timer, next, head, entry) {
461 list_del_init(&timer->entry);
462 if (timer->expires.cpu < ptime) {
463 timer->expires.cpu = 0;
464 } else {
465 timer->expires.cpu -= ptime;
466 }
467 }
468
469 ++head;
470 list_for_each_entry_safe(timer, next, head, entry) {
471 list_del_init(&timer->entry);
472 if (timer->expires.cpu < utime) {
473 timer->expires.cpu = 0;
474 } else {
475 timer->expires.cpu -= utime;
476 }
477 }
478
479 ++head;
480 list_for_each_entry_safe(timer, next, head, entry) {
481 list_del_init(&timer->entry);
482 if (timer->expires.sched < sum_exec_runtime) {
483 timer->expires.sched = 0;
484 } else {
485 timer->expires.sched -= sum_exec_runtime;
486 }
487 }
488}
489
490/*
491 * These are both called with the siglock held, when the current thread
492 * is being reaped. When the final (leader) thread in the group is reaped,
493 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
494 */
495void posix_cpu_timers_exit(struct task_struct *tsk)
496{
497 cleanup_timers(tsk->cpu_timers,
498 tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
499
500}
501void posix_cpu_timers_exit_group(struct task_struct *tsk)
502{
503 struct signal_struct *const sig = tsk->signal;
504
505 cleanup_timers(tsk->signal->cpu_timers,
506 tsk->utime + sig->utime, tsk->stime + sig->stime,
507 tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
508}
509
510static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
511{
512 /*
513 * That's all for this thread or process.
514 * We leave our residual in expires to be reported.
515 */
516 put_task_struct(timer->it.cpu.task);
517 timer->it.cpu.task = NULL;
518 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
519 timer->it.cpu.expires,
520 now);
521}
522
523static inline int expires_gt(cputime_t expires, cputime_t new_exp)
524{
525 return expires == 0 || expires > new_exp;
526}
527
528/*
529 * Insert the timer on the appropriate list before any timers that
530 * expire later. This must be called with the tasklist_lock held
531 * for reading, interrupts disabled and p->sighand->siglock taken.
532 */
533static void arm_timer(struct k_itimer *timer)
534{
535 struct task_struct *p = timer->it.cpu.task;
536 struct list_head *head, *listpos;
537 struct task_cputime *cputime_expires;
538 struct cpu_timer_list *const nt = &timer->it.cpu;
539 struct cpu_timer_list *next;
540
541 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
542 head = p->cpu_timers;
543 cputime_expires = &p->cputime_expires;
544 } else {
545 head = p->signal->cpu_timers;
546 cputime_expires = &p->signal->cputime_expires;
547 }
548 head += CPUCLOCK_WHICH(timer->it_clock);
549
550 listpos = head;
551 list_for_each_entry(next, head, entry) {
552 if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
553 break;
554 listpos = &next->entry;
555 }
556 list_add(&nt->entry, listpos);
557
558 if (listpos == head) {
559 union cpu_time_count *exp = &nt->expires;
560
561 /*
562 * We are the new earliest-expiring POSIX 1.b timer, hence
563 * need to update expiration cache. Take into account that
564 * for process timers we share expiration cache with itimers
565 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
566 */
567
568 switch (CPUCLOCK_WHICH(timer->it_clock)) {
569 case CPUCLOCK_PROF:
570 if (expires_gt(cputime_expires->prof_exp, exp->cpu))
571 cputime_expires->prof_exp = exp->cpu;
572 break;
573 case CPUCLOCK_VIRT:
574 if (expires_gt(cputime_expires->virt_exp, exp->cpu))
575 cputime_expires->virt_exp = exp->cpu;
576 break;
577 case CPUCLOCK_SCHED:
578 if (cputime_expires->sched_exp == 0 ||
579 cputime_expires->sched_exp > exp->sched)
580 cputime_expires->sched_exp = exp->sched;
581 break;
582 }
583 }
584}
585
586/*
587 * The timer is locked, fire it and arrange for its reload.
588 */
589static void cpu_timer_fire(struct k_itimer *timer)
590{
591 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
592 /*
593 * User don't want any signal.
594 */
595 timer->it.cpu.expires.sched = 0;
596 } else if (unlikely(timer->sigq == NULL)) {
597 /*
598 * This a special case for clock_nanosleep,
599 * not a normal timer from sys_timer_create.
600 */
601 wake_up_process(timer->it_process);
602 timer->it.cpu.expires.sched = 0;
603 } else if (timer->it.cpu.incr.sched == 0) {
604 /*
605 * One-shot timer. Clear it as soon as it's fired.
606 */
607 posix_timer_event(timer, 0);
608 timer->it.cpu.expires.sched = 0;
609 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
610 /*
611 * The signal did not get queued because the signal
612 * was ignored, so we won't get any callback to
613 * reload the timer. But we need to keep it
614 * ticking in case the signal is deliverable next time.
615 */
616 posix_cpu_timer_schedule(timer);
617 }
618}
619
620/*
621 * Sample a process (thread group) timer for the given group_leader task.
622 * Must be called with tasklist_lock held for reading.
623 */
624static int cpu_timer_sample_group(const clockid_t which_clock,
625 struct task_struct *p,
626 union cpu_time_count *cpu)
627{
628 struct task_cputime cputime;
629
630 thread_group_cputimer(p, &cputime);
631 switch (CPUCLOCK_WHICH(which_clock)) {
632 default:
633 return -EINVAL;
634 case CPUCLOCK_PROF:
635 cpu->cpu = cputime.utime + cputime.stime;
636 break;
637 case CPUCLOCK_VIRT:
638 cpu->cpu = cputime.utime;
639 break;
640 case CPUCLOCK_SCHED:
641 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
642 break;
643 }
644 return 0;
645}
646
647/*
648 * Guts of sys_timer_settime for CPU timers.
649 * This is called with the timer locked and interrupts disabled.
650 * If we return TIMER_RETRY, it's necessary to release the timer's lock
651 * and try again. (This happens when the timer is in the middle of firing.)
652 */
653static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
654 struct itimerspec *new, struct itimerspec *old)
655{
656 struct task_struct *p = timer->it.cpu.task;
657 union cpu_time_count old_expires, new_expires, old_incr, val;
658 int ret;
659
660 if (unlikely(p == NULL)) {
661 /*
662 * Timer refers to a dead task's clock.
663 */
664 return -ESRCH;
665 }
666
667 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
668
669 read_lock(&tasklist_lock);
670 /*
671 * We need the tasklist_lock to protect against reaping that
672 * clears p->sighand. If p has just been reaped, we can no
673 * longer get any information about it at all.
674 */
675 if (unlikely(p->sighand == NULL)) {
676 read_unlock(&tasklist_lock);
677 put_task_struct(p);
678 timer->it.cpu.task = NULL;
679 return -ESRCH;
680 }
681
682 /*
683 * Disarm any old timer after extracting its expiry time.
684 */
685 BUG_ON(!irqs_disabled());
686
687 ret = 0;
688 old_incr = timer->it.cpu.incr;
689 spin_lock(&p->sighand->siglock);
690 old_expires = timer->it.cpu.expires;
691 if (unlikely(timer->it.cpu.firing)) {
692 timer->it.cpu.firing = -1;
693 ret = TIMER_RETRY;
694 } else
695 list_del_init(&timer->it.cpu.entry);
696
697 /*
698 * We need to sample the current value to convert the new
699 * value from to relative and absolute, and to convert the
700 * old value from absolute to relative. To set a process
701 * timer, we need a sample to balance the thread expiry
702 * times (in arm_timer). With an absolute time, we must
703 * check if it's already passed. In short, we need a sample.
704 */
705 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
706 cpu_clock_sample(timer->it_clock, p, &val);
707 } else {
708 cpu_timer_sample_group(timer->it_clock, p, &val);
709 }
710
711 if (old) {
712 if (old_expires.sched == 0) {
713 old->it_value.tv_sec = 0;
714 old->it_value.tv_nsec = 0;
715 } else {
716 /*
717 * Update the timer in case it has
718 * overrun already. If it has,
719 * we'll report it as having overrun
720 * and with the next reloaded timer
721 * already ticking, though we are
722 * swallowing that pending
723 * notification here to install the
724 * new setting.
725 */
726 bump_cpu_timer(timer, val);
727 if (cpu_time_before(timer->it_clock, val,
728 timer->it.cpu.expires)) {
729 old_expires = cpu_time_sub(
730 timer->it_clock,
731 timer->it.cpu.expires, val);
732 sample_to_timespec(timer->it_clock,
733 old_expires,
734 &old->it_value);
735 } else {
736 old->it_value.tv_nsec = 1;
737 old->it_value.tv_sec = 0;
738 }
739 }
740 }
741
742 if (unlikely(ret)) {
743 /*
744 * We are colliding with the timer actually firing.
745 * Punt after filling in the timer's old value, and
746 * disable this firing since we are already reporting
747 * it as an overrun (thanks to bump_cpu_timer above).
748 */
749 spin_unlock(&p->sighand->siglock);
750 read_unlock(&tasklist_lock);
751 goto out;
752 }
753
754 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
755 cpu_time_add(timer->it_clock, &new_expires, val);
756 }
757
758 /*
759 * Install the new expiry time (or zero).
760 * For a timer with no notification action, we don't actually
761 * arm the timer (we'll just fake it for timer_gettime).
762 */
763 timer->it.cpu.expires = new_expires;
764 if (new_expires.sched != 0 &&
765 cpu_time_before(timer->it_clock, val, new_expires)) {
766 arm_timer(timer);
767 }
768
769 spin_unlock(&p->sighand->siglock);
770 read_unlock(&tasklist_lock);
771
772 /*
773 * Install the new reload setting, and
774 * set up the signal and overrun bookkeeping.
775 */
776 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
777 &new->it_interval);
778
779 /*
780 * This acts as a modification timestamp for the timer,
781 * so any automatic reload attempt will punt on seeing
782 * that we have reset the timer manually.
783 */
784 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
785 ~REQUEUE_PENDING;
786 timer->it_overrun_last = 0;
787 timer->it_overrun = -1;
788
789 if (new_expires.sched != 0 &&
790 !cpu_time_before(timer->it_clock, val, new_expires)) {
791 /*
792 * The designated time already passed, so we notify
793 * immediately, even if the thread never runs to
794 * accumulate more time on this clock.
795 */
796 cpu_timer_fire(timer);
797 }
798
799 ret = 0;
800 out:
801 if (old) {
802 sample_to_timespec(timer->it_clock,
803 old_incr, &old->it_interval);
804 }
805 return ret;
806}
807
808static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
809{
810 union cpu_time_count now;
811 struct task_struct *p = timer->it.cpu.task;
812 int clear_dead;
813
814 /*
815 * Easy part: convert the reload time.
816 */
817 sample_to_timespec(timer->it_clock,
818 timer->it.cpu.incr, &itp->it_interval);
819
820 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
821 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
822 return;
823 }
824
825 if (unlikely(p == NULL)) {
826 /*
827 * This task already died and the timer will never fire.
828 * In this case, expires is actually the dead value.
829 */
830 dead:
831 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
832 &itp->it_value);
833 return;
834 }
835
836 /*
837 * Sample the clock to take the difference with the expiry time.
838 */
839 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
840 cpu_clock_sample(timer->it_clock, p, &now);
841 clear_dead = p->exit_state;
842 } else {
843 read_lock(&tasklist_lock);
844 if (unlikely(p->sighand == NULL)) {
845 /*
846 * The process has been reaped.
847 * We can't even collect a sample any more.
848 * Call the timer disarmed, nothing else to do.
849 */
850 put_task_struct(p);
851 timer->it.cpu.task = NULL;
852 timer->it.cpu.expires.sched = 0;
853 read_unlock(&tasklist_lock);
854 goto dead;
855 } else {
856 cpu_timer_sample_group(timer->it_clock, p, &now);
857 clear_dead = (unlikely(p->exit_state) &&
858 thread_group_empty(p));
859 }
860 read_unlock(&tasklist_lock);
861 }
862
863 if (unlikely(clear_dead)) {
864 /*
865 * We've noticed that the thread is dead, but
866 * not yet reaped. Take this opportunity to
867 * drop our task ref.
868 */
869 clear_dead_task(timer, now);
870 goto dead;
871 }
872
873 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
874 sample_to_timespec(timer->it_clock,
875 cpu_time_sub(timer->it_clock,
876 timer->it.cpu.expires, now),
877 &itp->it_value);
878 } else {
879 /*
880 * The timer should have expired already, but the firing
881 * hasn't taken place yet. Say it's just about to expire.
882 */
883 itp->it_value.tv_nsec = 1;
884 itp->it_value.tv_sec = 0;
885 }
886}
887
888/*
889 * Check for any per-thread CPU timers that have fired and move them off
890 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
891 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
892 */
893static void check_thread_timers(struct task_struct *tsk,
894 struct list_head *firing)
895{
896 int maxfire;
897 struct list_head *timers = tsk->cpu_timers;
898 struct signal_struct *const sig = tsk->signal;
899 unsigned long soft;
900
901 maxfire = 20;
902 tsk->cputime_expires.prof_exp = 0;
903 while (!list_empty(timers)) {
904 struct cpu_timer_list *t = list_first_entry(timers,
905 struct cpu_timer_list,
906 entry);
907 if (!--maxfire || prof_ticks(tsk) < t->expires.cpu) {
908 tsk->cputime_expires.prof_exp = t->expires.cpu;
909 break;
910 }
911 t->firing = 1;
912 list_move_tail(&t->entry, firing);
913 }
914
915 ++timers;
916 maxfire = 20;
917 tsk->cputime_expires.virt_exp = 0;
918 while (!list_empty(timers)) {
919 struct cpu_timer_list *t = list_first_entry(timers,
920 struct cpu_timer_list,
921 entry);
922 if (!--maxfire || virt_ticks(tsk) < t->expires.cpu) {
923 tsk->cputime_expires.virt_exp = t->expires.cpu;
924 break;
925 }
926 t->firing = 1;
927 list_move_tail(&t->entry, firing);
928 }
929
930 ++timers;
931 maxfire = 20;
932 tsk->cputime_expires.sched_exp = 0;
933 while (!list_empty(timers)) {
934 struct cpu_timer_list *t = list_first_entry(timers,
935 struct cpu_timer_list,
936 entry);
937 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
938 tsk->cputime_expires.sched_exp = t->expires.sched;
939 break;
940 }
941 t->firing = 1;
942 list_move_tail(&t->entry, firing);
943 }
944
945 /*
946 * Check for the special case thread timers.
947 */
948 soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
949 if (soft != RLIM_INFINITY) {
950 unsigned long hard =
951 ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
952
953 if (hard != RLIM_INFINITY &&
954 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
955 /*
956 * At the hard limit, we just die.
957 * No need to calculate anything else now.
958 */
959 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
960 return;
961 }
962 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
963 /*
964 * At the soft limit, send a SIGXCPU every second.
965 */
966 if (soft < hard) {
967 soft += USEC_PER_SEC;
968 sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
969 }
970 printk(KERN_INFO
971 "RT Watchdog Timeout: %s[%d]\n",
972 tsk->comm, task_pid_nr(tsk));
973 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
974 }
975 }
976}
977
978static void stop_process_timers(struct signal_struct *sig)
979{
980 struct thread_group_cputimer *cputimer = &sig->cputimer;
981 unsigned long flags;
982
983 raw_spin_lock_irqsave(&cputimer->lock, flags);
984 cputimer->running = 0;
985 raw_spin_unlock_irqrestore(&cputimer->lock, flags);
986}
987
988static u32 onecputick;
989
990static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
991 cputime_t *expires, cputime_t cur_time, int signo)
992{
993 if (!it->expires)
994 return;
995
996 if (cur_time >= it->expires) {
997 if (it->incr) {
998 it->expires += it->incr;
999 it->error += it->incr_error;
1000 if (it->error >= onecputick) {
1001 it->expires -= cputime_one_jiffy;
1002 it->error -= onecputick;
1003 }
1004 } else {
1005 it->expires = 0;
1006 }
1007
1008 trace_itimer_expire(signo == SIGPROF ?
1009 ITIMER_PROF : ITIMER_VIRTUAL,
1010 tsk->signal->leader_pid, cur_time);
1011 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
1012 }
1013
1014 if (it->expires && (!*expires || it->expires < *expires)) {
1015 *expires = it->expires;
1016 }
1017}
1018
1019/**
1020 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1021 *
1022 * @cputime: The struct to compare.
1023 *
1024 * Checks @cputime to see if all fields are zero. Returns true if all fields
1025 * are zero, false if any field is nonzero.
1026 */
1027static inline int task_cputime_zero(const struct task_cputime *cputime)
1028{
1029 if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
1030 return 1;
1031 return 0;
1032}
1033
1034/*
1035 * Check for any per-thread CPU timers that have fired and move them
1036 * off the tsk->*_timers list onto the firing list. Per-thread timers
1037 * have already been taken off.
1038 */
1039static void check_process_timers(struct task_struct *tsk,
1040 struct list_head *firing)
1041{
1042 int maxfire;
1043 struct signal_struct *const sig = tsk->signal;
1044 cputime_t utime, ptime, virt_expires, prof_expires;
1045 unsigned long long sum_sched_runtime, sched_expires;
1046 struct list_head *timers = sig->cpu_timers;
1047 struct task_cputime cputime;
1048 unsigned long soft;
1049
1050 /*
1051 * Collect the current process totals.
1052 */
1053 thread_group_cputimer(tsk, &cputime);
1054 utime = cputime.utime;
1055 ptime = utime + cputime.stime;
1056 sum_sched_runtime = cputime.sum_exec_runtime;
1057 maxfire = 20;
1058 prof_expires = 0;
1059 while (!list_empty(timers)) {
1060 struct cpu_timer_list *tl = list_first_entry(timers,
1061 struct cpu_timer_list,
1062 entry);
1063 if (!--maxfire || ptime < tl->expires.cpu) {
1064 prof_expires = tl->expires.cpu;
1065 break;
1066 }
1067 tl->firing = 1;
1068 list_move_tail(&tl->entry, firing);
1069 }
1070
1071 ++timers;
1072 maxfire = 20;
1073 virt_expires = 0;
1074 while (!list_empty(timers)) {
1075 struct cpu_timer_list *tl = list_first_entry(timers,
1076 struct cpu_timer_list,
1077 entry);
1078 if (!--maxfire || utime < tl->expires.cpu) {
1079 virt_expires = tl->expires.cpu;
1080 break;
1081 }
1082 tl->firing = 1;
1083 list_move_tail(&tl->entry, firing);
1084 }
1085
1086 ++timers;
1087 maxfire = 20;
1088 sched_expires = 0;
1089 while (!list_empty(timers)) {
1090 struct cpu_timer_list *tl = list_first_entry(timers,
1091 struct cpu_timer_list,
1092 entry);
1093 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1094 sched_expires = tl->expires.sched;
1095 break;
1096 }
1097 tl->firing = 1;
1098 list_move_tail(&tl->entry, firing);
1099 }
1100
1101 /*
1102 * Check for the special case process timers.
1103 */
1104 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
1105 SIGPROF);
1106 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
1107 SIGVTALRM);
1108 soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
1109 if (soft != RLIM_INFINITY) {
1110 unsigned long psecs = cputime_to_secs(ptime);
1111 unsigned long hard =
1112 ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
1113 cputime_t x;
1114 if (psecs >= hard) {
1115 /*
1116 * At the hard limit, we just die.
1117 * No need to calculate anything else now.
1118 */
1119 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1120 return;
1121 }
1122 if (psecs >= soft) {
1123 /*
1124 * At the soft limit, send a SIGXCPU every second.
1125 */
1126 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1127 if (soft < hard) {
1128 soft++;
1129 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
1130 }
1131 }
1132 x = secs_to_cputime(soft);
1133 if (!prof_expires || x < prof_expires) {
1134 prof_expires = x;
1135 }
1136 }
1137
1138 sig->cputime_expires.prof_exp = prof_expires;
1139 sig->cputime_expires.virt_exp = virt_expires;
1140 sig->cputime_expires.sched_exp = sched_expires;
1141 if (task_cputime_zero(&sig->cputime_expires))
1142 stop_process_timers(sig);
1143}
1144
1145/*
1146 * This is called from the signal code (via do_schedule_next_timer)
1147 * when the last timer signal was delivered and we have to reload the timer.
1148 */
1149void posix_cpu_timer_schedule(struct k_itimer *timer)
1150{
1151 struct task_struct *p = timer->it.cpu.task;
1152 union cpu_time_count now;
1153
1154 if (unlikely(p == NULL))
1155 /*
1156 * The task was cleaned up already, no future firings.
1157 */
1158 goto out;
1159
1160 /*
1161 * Fetch the current sample and update the timer's expiry time.
1162 */
1163 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1164 cpu_clock_sample(timer->it_clock, p, &now);
1165 bump_cpu_timer(timer, now);
1166 if (unlikely(p->exit_state)) {
1167 clear_dead_task(timer, now);
1168 goto out;
1169 }
1170 read_lock(&tasklist_lock); /* arm_timer needs it. */
1171 spin_lock(&p->sighand->siglock);
1172 } else {
1173 read_lock(&tasklist_lock);
1174 if (unlikely(p->sighand == NULL)) {
1175 /*
1176 * The process has been reaped.
1177 * We can't even collect a sample any more.
1178 */
1179 put_task_struct(p);
1180 timer->it.cpu.task = p = NULL;
1181 timer->it.cpu.expires.sched = 0;
1182 goto out_unlock;
1183 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1184 /*
1185 * We've noticed that the thread is dead, but
1186 * not yet reaped. Take this opportunity to
1187 * drop our task ref.
1188 */
1189 clear_dead_task(timer, now);
1190 goto out_unlock;
1191 }
1192 spin_lock(&p->sighand->siglock);
1193 cpu_timer_sample_group(timer->it_clock, p, &now);
1194 bump_cpu_timer(timer, now);
1195 /* Leave the tasklist_lock locked for the call below. */
1196 }
1197
1198 /*
1199 * Now re-arm for the new expiry time.
1200 */
1201 BUG_ON(!irqs_disabled());
1202 arm_timer(timer);
1203 spin_unlock(&p->sighand->siglock);
1204
1205out_unlock:
1206 read_unlock(&tasklist_lock);
1207
1208out:
1209 timer->it_overrun_last = timer->it_overrun;
1210 timer->it_overrun = -1;
1211 ++timer->it_requeue_pending;
1212}
1213
1214/**
1215 * task_cputime_expired - Compare two task_cputime entities.
1216 *
1217 * @sample: The task_cputime structure to be checked for expiration.
1218 * @expires: Expiration times, against which @sample will be checked.
1219 *
1220 * Checks @sample against @expires to see if any field of @sample has expired.
1221 * Returns true if any field of the former is greater than the corresponding
1222 * field of the latter if the latter field is set. Otherwise returns false.
1223 */
1224static inline int task_cputime_expired(const struct task_cputime *sample,
1225 const struct task_cputime *expires)
1226{
1227 if (expires->utime && sample->utime >= expires->utime)
1228 return 1;
1229 if (expires->stime && sample->utime + sample->stime >= expires->stime)
1230 return 1;
1231 if (expires->sum_exec_runtime != 0 &&
1232 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1233 return 1;
1234 return 0;
1235}
1236
1237/**
1238 * fastpath_timer_check - POSIX CPU timers fast path.
1239 *
1240 * @tsk: The task (thread) being checked.
1241 *
1242 * Check the task and thread group timers. If both are zero (there are no
1243 * timers set) return false. Otherwise snapshot the task and thread group
1244 * timers and compare them with the corresponding expiration times. Return
1245 * true if a timer has expired, else return false.
1246 */
1247static inline int fastpath_timer_check(struct task_struct *tsk)
1248{
1249 struct signal_struct *sig;
1250
1251 if (!task_cputime_zero(&tsk->cputime_expires)) {
1252 struct task_cputime task_sample = {
1253 .utime = tsk->utime,
1254 .stime = tsk->stime,
1255 .sum_exec_runtime = tsk->se.sum_exec_runtime
1256 };
1257
1258 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1259 return 1;
1260 }
1261
1262 sig = tsk->signal;
1263 if (sig->cputimer.running) {
1264 struct task_cputime group_sample;
1265
1266 raw_spin_lock(&sig->cputimer.lock);
1267 group_sample = sig->cputimer.cputime;
1268 raw_spin_unlock(&sig->cputimer.lock);
1269
1270 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1271 return 1;
1272 }
1273
1274 return 0;
1275}
1276
1277/*
1278 * This is called from the timer interrupt handler. The irq handler has
1279 * already updated our counts. We need to check if any timers fire now.
1280 * Interrupts are disabled.
1281 */
1282void run_posix_cpu_timers(struct task_struct *tsk)
1283{
1284 LIST_HEAD(firing);
1285 struct k_itimer *timer, *next;
1286 unsigned long flags;
1287
1288 BUG_ON(!irqs_disabled());
1289
1290 /*
1291 * The fast path checks that there are no expired thread or thread
1292 * group timers. If that's so, just return.
1293 */
1294 if (!fastpath_timer_check(tsk))
1295 return;
1296
1297 if (!lock_task_sighand(tsk, &flags))
1298 return;
1299 /*
1300 * Here we take off tsk->signal->cpu_timers[N] and
1301 * tsk->cpu_timers[N] all the timers that are firing, and
1302 * put them on the firing list.
1303 */
1304 check_thread_timers(tsk, &firing);
1305 /*
1306 * If there are any active process wide timers (POSIX 1.b, itimers,
1307 * RLIMIT_CPU) cputimer must be running.
1308 */
1309 if (tsk->signal->cputimer.running)
1310 check_process_timers(tsk, &firing);
1311
1312 /*
1313 * We must release these locks before taking any timer's lock.
1314 * There is a potential race with timer deletion here, as the
1315 * siglock now protects our private firing list. We have set
1316 * the firing flag in each timer, so that a deletion attempt
1317 * that gets the timer lock before we do will give it up and
1318 * spin until we've taken care of that timer below.
1319 */
1320 unlock_task_sighand(tsk, &flags);
1321
1322 /*
1323 * Now that all the timers on our list have the firing flag,
1324 * no one will touch their list entries but us. We'll take
1325 * each timer's lock before clearing its firing flag, so no
1326 * timer call will interfere.
1327 */
1328 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1329 int cpu_firing;
1330
1331 spin_lock(&timer->it_lock);
1332 list_del_init(&timer->it.cpu.entry);
1333 cpu_firing = timer->it.cpu.firing;
1334 timer->it.cpu.firing = 0;
1335 /*
1336 * The firing flag is -1 if we collided with a reset
1337 * of the timer, which already reported this
1338 * almost-firing as an overrun. So don't generate an event.
1339 */
1340 if (likely(cpu_firing >= 0))
1341 cpu_timer_fire(timer);
1342 spin_unlock(&timer->it_lock);
1343 }
1344}
1345
1346/*
1347 * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1348 * The tsk->sighand->siglock must be held by the caller.
1349 */
1350void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1351 cputime_t *newval, cputime_t *oldval)
1352{
1353 union cpu_time_count now;
1354
1355 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1356 cpu_timer_sample_group(clock_idx, tsk, &now);
1357
1358 if (oldval) {
1359 /*
1360 * We are setting itimer. The *oldval is absolute and we update
1361 * it to be relative, *newval argument is relative and we update
1362 * it to be absolute.
1363 */
1364 if (*oldval) {
1365 if (*oldval <= now.cpu) {
1366 /* Just about to fire. */
1367 *oldval = cputime_one_jiffy;
1368 } else {
1369 *oldval -= now.cpu;
1370 }
1371 }
1372
1373 if (!*newval)
1374 return;
1375 *newval += now.cpu;
1376 }
1377
1378 /*
1379 * Update expiration cache if we are the earliest timer, or eventually
1380 * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1381 */
1382 switch (clock_idx) {
1383 case CPUCLOCK_PROF:
1384 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1385 tsk->signal->cputime_expires.prof_exp = *newval;
1386 break;
1387 case CPUCLOCK_VIRT:
1388 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1389 tsk->signal->cputime_expires.virt_exp = *newval;
1390 break;
1391 }
1392}
1393
1394static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1395 struct timespec *rqtp, struct itimerspec *it)
1396{
1397 struct k_itimer timer;
1398 int error;
1399
1400 /*
1401 * Set up a temporary timer and then wait for it to go off.
1402 */
1403 memset(&timer, 0, sizeof timer);
1404 spin_lock_init(&timer.it_lock);
1405 timer.it_clock = which_clock;
1406 timer.it_overrun = -1;
1407 error = posix_cpu_timer_create(&timer);
1408 timer.it_process = current;
1409 if (!error) {
1410 static struct itimerspec zero_it;
1411
1412 memset(it, 0, sizeof *it);
1413 it->it_value = *rqtp;
1414
1415 spin_lock_irq(&timer.it_lock);
1416 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1417 if (error) {
1418 spin_unlock_irq(&timer.it_lock);
1419 return error;
1420 }
1421
1422 while (!signal_pending(current)) {
1423 if (timer.it.cpu.expires.sched == 0) {
1424 /*
1425 * Our timer fired and was reset.
1426 */
1427 spin_unlock_irq(&timer.it_lock);
1428 return 0;
1429 }
1430
1431 /*
1432 * Block until cpu_timer_fire (or a signal) wakes us.
1433 */
1434 __set_current_state(TASK_INTERRUPTIBLE);
1435 spin_unlock_irq(&timer.it_lock);
1436 schedule();
1437 spin_lock_irq(&timer.it_lock);
1438 }
1439
1440 /*
1441 * We were interrupted by a signal.
1442 */
1443 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1444 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1445 spin_unlock_irq(&timer.it_lock);
1446
1447 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1448 /*
1449 * It actually did fire already.
1450 */
1451 return 0;
1452 }
1453
1454 error = -ERESTART_RESTARTBLOCK;
1455 }
1456
1457 return error;
1458}
1459
1460static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1461
1462static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1463 struct timespec *rqtp, struct timespec __user *rmtp)
1464{
1465 struct restart_block *restart_block =
1466 ¤t_thread_info()->restart_block;
1467 struct itimerspec it;
1468 int error;
1469
1470 /*
1471 * Diagnose required errors first.
1472 */
1473 if (CPUCLOCK_PERTHREAD(which_clock) &&
1474 (CPUCLOCK_PID(which_clock) == 0 ||
1475 CPUCLOCK_PID(which_clock) == current->pid))
1476 return -EINVAL;
1477
1478 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1479
1480 if (error == -ERESTART_RESTARTBLOCK) {
1481
1482 if (flags & TIMER_ABSTIME)
1483 return -ERESTARTNOHAND;
1484 /*
1485 * Report back to the user the time still remaining.
1486 */
1487 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1488 return -EFAULT;
1489
1490 restart_block->fn = posix_cpu_nsleep_restart;
1491 restart_block->nanosleep.clockid = which_clock;
1492 restart_block->nanosleep.rmtp = rmtp;
1493 restart_block->nanosleep.expires = timespec_to_ns(rqtp);
1494 }
1495 return error;
1496}
1497
1498static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1499{
1500 clockid_t which_clock = restart_block->nanosleep.clockid;
1501 struct timespec t;
1502 struct itimerspec it;
1503 int error;
1504
1505 t = ns_to_timespec(restart_block->nanosleep.expires);
1506
1507 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1508
1509 if (error == -ERESTART_RESTARTBLOCK) {
1510 struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
1511 /*
1512 * Report back to the user the time still remaining.
1513 */
1514 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1515 return -EFAULT;
1516
1517 restart_block->nanosleep.expires = timespec_to_ns(&t);
1518 }
1519 return error;
1520
1521}
1522
1523#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1524#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1525
1526static int process_cpu_clock_getres(const clockid_t which_clock,
1527 struct timespec *tp)
1528{
1529 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1530}
1531static int process_cpu_clock_get(const clockid_t which_clock,
1532 struct timespec *tp)
1533{
1534 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1535}
1536static int process_cpu_timer_create(struct k_itimer *timer)
1537{
1538 timer->it_clock = PROCESS_CLOCK;
1539 return posix_cpu_timer_create(timer);
1540}
1541static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1542 struct timespec *rqtp,
1543 struct timespec __user *rmtp)
1544{
1545 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1546}
1547static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1548{
1549 return -EINVAL;
1550}
1551static int thread_cpu_clock_getres(const clockid_t which_clock,
1552 struct timespec *tp)
1553{
1554 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1555}
1556static int thread_cpu_clock_get(const clockid_t which_clock,
1557 struct timespec *tp)
1558{
1559 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1560}
1561static int thread_cpu_timer_create(struct k_itimer *timer)
1562{
1563 timer->it_clock = THREAD_CLOCK;
1564 return posix_cpu_timer_create(timer);
1565}
1566
1567struct k_clock clock_posix_cpu = {
1568 .clock_getres = posix_cpu_clock_getres,
1569 .clock_set = posix_cpu_clock_set,
1570 .clock_get = posix_cpu_clock_get,
1571 .timer_create = posix_cpu_timer_create,
1572 .nsleep = posix_cpu_nsleep,
1573 .nsleep_restart = posix_cpu_nsleep_restart,
1574 .timer_set = posix_cpu_timer_set,
1575 .timer_del = posix_cpu_timer_del,
1576 .timer_get = posix_cpu_timer_get,
1577};
1578
1579static __init int init_posix_cpu_timers(void)
1580{
1581 struct k_clock process = {
1582 .clock_getres = process_cpu_clock_getres,
1583 .clock_get = process_cpu_clock_get,
1584 .timer_create = process_cpu_timer_create,
1585 .nsleep = process_cpu_nsleep,
1586 .nsleep_restart = process_cpu_nsleep_restart,
1587 };
1588 struct k_clock thread = {
1589 .clock_getres = thread_cpu_clock_getres,
1590 .clock_get = thread_cpu_clock_get,
1591 .timer_create = thread_cpu_timer_create,
1592 };
1593 struct timespec ts;
1594
1595 posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1596 posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1597
1598 cputime_to_timespec(cputime_one_jiffy, &ts);
1599 onecputick = ts.tv_nsec;
1600 WARN_ON(ts.tv_sec != 0);
1601
1602 return 0;
1603}
1604__initcall(init_posix_cpu_timers);