Linux 2.6.33-rc6
[cris-mirror.git] / kernel / posix-cpu-timers.c
blob438ff4523513b945962e50a98eb8d4e2fbb28f5d
1 /*
2 * Implement CPU time clocks for the POSIX clock interface.
3 */
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>
14 * Called after updating RLIMIT_CPU to set timer expiration if necessary.
16 void update_rlimit_cpu(unsigned long rlim_new)
18 cputime_t cputime = secs_to_cputime(rlim_new);
19 struct signal_struct *const sig = current->signal;
21 if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) ||
22 cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) {
23 spin_lock_irq(&current->sighand->siglock);
24 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
25 spin_unlock_irq(&current->sighand->siglock);
29 static int check_clock(const clockid_t which_clock)
31 int error = 0;
32 struct task_struct *p;
33 const pid_t pid = CPUCLOCK_PID(which_clock);
35 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
36 return -EINVAL;
38 if (pid == 0)
39 return 0;
41 read_lock(&tasklist_lock);
42 p = find_task_by_vpid(pid);
43 if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
44 same_thread_group(p, current) : thread_group_leader(p))) {
45 error = -EINVAL;
47 read_unlock(&tasklist_lock);
49 return error;
52 static inline union cpu_time_count
53 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
55 union cpu_time_count ret;
56 ret.sched = 0; /* high half always zero when .cpu used */
57 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
58 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
59 } else {
60 ret.cpu = timespec_to_cputime(tp);
62 return ret;
65 static void sample_to_timespec(const clockid_t which_clock,
66 union cpu_time_count cpu,
67 struct timespec *tp)
69 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
70 *tp = ns_to_timespec(cpu.sched);
71 else
72 cputime_to_timespec(cpu.cpu, tp);
75 static inline int cpu_time_before(const clockid_t which_clock,
76 union cpu_time_count now,
77 union cpu_time_count then)
79 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
80 return now.sched < then.sched;
81 } else {
82 return cputime_lt(now.cpu, then.cpu);
85 static inline void cpu_time_add(const clockid_t which_clock,
86 union cpu_time_count *acc,
87 union cpu_time_count val)
89 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
90 acc->sched += val.sched;
91 } else {
92 acc->cpu = cputime_add(acc->cpu, val.cpu);
95 static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
96 union cpu_time_count a,
97 union cpu_time_count b)
99 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
100 a.sched -= b.sched;
101 } else {
102 a.cpu = cputime_sub(a.cpu, b.cpu);
104 return a;
108 * Divide and limit the result to res >= 1
110 * This is necessary to prevent signal delivery starvation, when the result of
111 * the division would be rounded down to 0.
113 static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
115 cputime_t res = cputime_div(time, div);
117 return max_t(cputime_t, res, 1);
121 * Update expiry time from increment, and increase overrun count,
122 * given the current clock sample.
124 static void bump_cpu_timer(struct k_itimer *timer,
125 union cpu_time_count now)
127 int i;
129 if (timer->it.cpu.incr.sched == 0)
130 return;
132 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
133 unsigned long long delta, incr;
135 if (now.sched < timer->it.cpu.expires.sched)
136 return;
137 incr = timer->it.cpu.incr.sched;
138 delta = now.sched + incr - timer->it.cpu.expires.sched;
139 /* Don't use (incr*2 < delta), incr*2 might overflow. */
140 for (i = 0; incr < delta - incr; i++)
141 incr = incr << 1;
142 for (; i >= 0; incr >>= 1, i--) {
143 if (delta < incr)
144 continue;
145 timer->it.cpu.expires.sched += incr;
146 timer->it_overrun += 1 << i;
147 delta -= incr;
149 } else {
150 cputime_t delta, incr;
152 if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
153 return;
154 incr = timer->it.cpu.incr.cpu;
155 delta = cputime_sub(cputime_add(now.cpu, incr),
156 timer->it.cpu.expires.cpu);
157 /* Don't use (incr*2 < delta), incr*2 might overflow. */
158 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
159 incr = cputime_add(incr, incr);
160 for (; i >= 0; incr = cputime_halve(incr), i--) {
161 if (cputime_lt(delta, incr))
162 continue;
163 timer->it.cpu.expires.cpu =
164 cputime_add(timer->it.cpu.expires.cpu, incr);
165 timer->it_overrun += 1 << i;
166 delta = cputime_sub(delta, incr);
171 static inline cputime_t prof_ticks(struct task_struct *p)
173 return cputime_add(p->utime, p->stime);
175 static inline cputime_t virt_ticks(struct task_struct *p)
177 return p->utime;
180 int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
182 int error = check_clock(which_clock);
183 if (!error) {
184 tp->tv_sec = 0;
185 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
186 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
188 * If sched_clock is using a cycle counter, we
189 * don't have any idea of its true resolution
190 * exported, but it is much more than 1s/HZ.
192 tp->tv_nsec = 1;
195 return error;
198 int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
201 * You can never reset a CPU clock, but we check for other errors
202 * in the call before failing with EPERM.
204 int error = check_clock(which_clock);
205 if (error == 0) {
206 error = -EPERM;
208 return error;
213 * Sample a per-thread clock for the given task.
215 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
216 union cpu_time_count *cpu)
218 switch (CPUCLOCK_WHICH(which_clock)) {
219 default:
220 return -EINVAL;
221 case CPUCLOCK_PROF:
222 cpu->cpu = prof_ticks(p);
223 break;
224 case CPUCLOCK_VIRT:
225 cpu->cpu = virt_ticks(p);
226 break;
227 case CPUCLOCK_SCHED:
228 cpu->sched = task_sched_runtime(p);
229 break;
231 return 0;
234 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
236 struct sighand_struct *sighand;
237 struct signal_struct *sig;
238 struct task_struct *t;
240 *times = INIT_CPUTIME;
242 rcu_read_lock();
243 sighand = rcu_dereference(tsk->sighand);
244 if (!sighand)
245 goto out;
247 sig = tsk->signal;
249 t = tsk;
250 do {
251 times->utime = cputime_add(times->utime, t->utime);
252 times->stime = cputime_add(times->stime, t->stime);
253 times->sum_exec_runtime += t->se.sum_exec_runtime;
255 t = next_thread(t);
256 } while (t != tsk);
258 times->utime = cputime_add(times->utime, sig->utime);
259 times->stime = cputime_add(times->stime, sig->stime);
260 times->sum_exec_runtime += sig->sum_sched_runtime;
261 out:
262 rcu_read_unlock();
265 static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
267 if (cputime_gt(b->utime, a->utime))
268 a->utime = b->utime;
270 if (cputime_gt(b->stime, a->stime))
271 a->stime = b->stime;
273 if (b->sum_exec_runtime > a->sum_exec_runtime)
274 a->sum_exec_runtime = b->sum_exec_runtime;
277 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
279 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
280 struct task_cputime sum;
281 unsigned long flags;
283 spin_lock_irqsave(&cputimer->lock, flags);
284 if (!cputimer->running) {
285 cputimer->running = 1;
287 * The POSIX timer interface allows for absolute time expiry
288 * values through the TIMER_ABSTIME flag, therefore we have
289 * to synchronize the timer to the clock every time we start
290 * it.
292 thread_group_cputime(tsk, &sum);
293 update_gt_cputime(&cputimer->cputime, &sum);
295 *times = cputimer->cputime;
296 spin_unlock_irqrestore(&cputimer->lock, flags);
300 * Sample a process (thread group) clock for the given group_leader task.
301 * Must be called with tasklist_lock held for reading.
303 static int cpu_clock_sample_group(const clockid_t which_clock,
304 struct task_struct *p,
305 union cpu_time_count *cpu)
307 struct task_cputime cputime;
309 switch (CPUCLOCK_WHICH(which_clock)) {
310 default:
311 return -EINVAL;
312 case CPUCLOCK_PROF:
313 thread_group_cputime(p, &cputime);
314 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
315 break;
316 case CPUCLOCK_VIRT:
317 thread_group_cputime(p, &cputime);
318 cpu->cpu = cputime.utime;
319 break;
320 case CPUCLOCK_SCHED:
321 cpu->sched = thread_group_sched_runtime(p);
322 break;
324 return 0;
328 int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
330 const pid_t pid = CPUCLOCK_PID(which_clock);
331 int error = -EINVAL;
332 union cpu_time_count rtn;
334 if (pid == 0) {
336 * Special case constant value for our own clocks.
337 * We don't have to do any lookup to find ourselves.
339 if (CPUCLOCK_PERTHREAD(which_clock)) {
341 * Sampling just ourselves we can do with no locking.
343 error = cpu_clock_sample(which_clock,
344 current, &rtn);
345 } else {
346 read_lock(&tasklist_lock);
347 error = cpu_clock_sample_group(which_clock,
348 current, &rtn);
349 read_unlock(&tasklist_lock);
351 } else {
353 * Find the given PID, and validate that the caller
354 * should be able to see it.
356 struct task_struct *p;
357 rcu_read_lock();
358 p = find_task_by_vpid(pid);
359 if (p) {
360 if (CPUCLOCK_PERTHREAD(which_clock)) {
361 if (same_thread_group(p, current)) {
362 error = cpu_clock_sample(which_clock,
363 p, &rtn);
365 } else {
366 read_lock(&tasklist_lock);
367 if (thread_group_leader(p) && p->signal) {
368 error =
369 cpu_clock_sample_group(which_clock,
370 p, &rtn);
372 read_unlock(&tasklist_lock);
375 rcu_read_unlock();
378 if (error)
379 return error;
380 sample_to_timespec(which_clock, rtn, tp);
381 return 0;
386 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
387 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
388 * new timer already all-zeros initialized.
390 int posix_cpu_timer_create(struct k_itimer *new_timer)
392 int ret = 0;
393 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
394 struct task_struct *p;
396 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
397 return -EINVAL;
399 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
401 read_lock(&tasklist_lock);
402 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
403 if (pid == 0) {
404 p = current;
405 } else {
406 p = find_task_by_vpid(pid);
407 if (p && !same_thread_group(p, current))
408 p = NULL;
410 } else {
411 if (pid == 0) {
412 p = current->group_leader;
413 } else {
414 p = find_task_by_vpid(pid);
415 if (p && !thread_group_leader(p))
416 p = NULL;
419 new_timer->it.cpu.task = p;
420 if (p) {
421 get_task_struct(p);
422 } else {
423 ret = -EINVAL;
425 read_unlock(&tasklist_lock);
427 return ret;
431 * Clean up a CPU-clock timer that is about to be destroyed.
432 * This is called from timer deletion with the timer already locked.
433 * If we return TIMER_RETRY, it's necessary to release the timer's lock
434 * and try again. (This happens when the timer is in the middle of firing.)
436 int posix_cpu_timer_del(struct k_itimer *timer)
438 struct task_struct *p = timer->it.cpu.task;
439 int ret = 0;
441 if (likely(p != NULL)) {
442 read_lock(&tasklist_lock);
443 if (unlikely(p->signal == NULL)) {
445 * We raced with the reaping of the task.
446 * The deletion should have cleared us off the list.
448 BUG_ON(!list_empty(&timer->it.cpu.entry));
449 } else {
450 spin_lock(&p->sighand->siglock);
451 if (timer->it.cpu.firing)
452 ret = TIMER_RETRY;
453 else
454 list_del(&timer->it.cpu.entry);
455 spin_unlock(&p->sighand->siglock);
457 read_unlock(&tasklist_lock);
459 if (!ret)
460 put_task_struct(p);
463 return ret;
467 * Clean out CPU timers still ticking when a thread exited. The task
468 * pointer is cleared, and the expiry time is replaced with the residual
469 * time for later timer_gettime calls to return.
470 * This must be called with the siglock held.
472 static void cleanup_timers(struct list_head *head,
473 cputime_t utime, cputime_t stime,
474 unsigned long long sum_exec_runtime)
476 struct cpu_timer_list *timer, *next;
477 cputime_t ptime = cputime_add(utime, stime);
479 list_for_each_entry_safe(timer, next, head, entry) {
480 list_del_init(&timer->entry);
481 if (cputime_lt(timer->expires.cpu, ptime)) {
482 timer->expires.cpu = cputime_zero;
483 } else {
484 timer->expires.cpu = cputime_sub(timer->expires.cpu,
485 ptime);
489 ++head;
490 list_for_each_entry_safe(timer, next, head, entry) {
491 list_del_init(&timer->entry);
492 if (cputime_lt(timer->expires.cpu, utime)) {
493 timer->expires.cpu = cputime_zero;
494 } else {
495 timer->expires.cpu = cputime_sub(timer->expires.cpu,
496 utime);
500 ++head;
501 list_for_each_entry_safe(timer, next, head, entry) {
502 list_del_init(&timer->entry);
503 if (timer->expires.sched < sum_exec_runtime) {
504 timer->expires.sched = 0;
505 } else {
506 timer->expires.sched -= sum_exec_runtime;
512 * These are both called with the siglock held, when the current thread
513 * is being reaped. When the final (leader) thread in the group is reaped,
514 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
516 void posix_cpu_timers_exit(struct task_struct *tsk)
518 cleanup_timers(tsk->cpu_timers,
519 tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
522 void posix_cpu_timers_exit_group(struct task_struct *tsk)
524 struct signal_struct *const sig = tsk->signal;
526 cleanup_timers(tsk->signal->cpu_timers,
527 cputime_add(tsk->utime, sig->utime),
528 cputime_add(tsk->stime, sig->stime),
529 tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
532 static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
535 * That's all for this thread or process.
536 * We leave our residual in expires to be reported.
538 put_task_struct(timer->it.cpu.task);
539 timer->it.cpu.task = NULL;
540 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
541 timer->it.cpu.expires,
542 now);
545 static inline int expires_gt(cputime_t expires, cputime_t new_exp)
547 return cputime_eq(expires, cputime_zero) ||
548 cputime_gt(expires, new_exp);
551 static inline int expires_le(cputime_t expires, cputime_t new_exp)
553 return !cputime_eq(expires, cputime_zero) &&
554 cputime_le(expires, new_exp);
557 * Insert the timer on the appropriate list before any timers that
558 * expire later. This must be called with the tasklist_lock held
559 * for reading, and interrupts disabled.
561 static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
563 struct task_struct *p = timer->it.cpu.task;
564 struct list_head *head, *listpos;
565 struct cpu_timer_list *const nt = &timer->it.cpu;
566 struct cpu_timer_list *next;
567 unsigned long i;
569 head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
570 p->cpu_timers : p->signal->cpu_timers);
571 head += CPUCLOCK_WHICH(timer->it_clock);
573 BUG_ON(!irqs_disabled());
574 spin_lock(&p->sighand->siglock);
576 listpos = head;
577 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
578 list_for_each_entry(next, head, entry) {
579 if (next->expires.sched > nt->expires.sched)
580 break;
581 listpos = &next->entry;
583 } else {
584 list_for_each_entry(next, head, entry) {
585 if (cputime_gt(next->expires.cpu, nt->expires.cpu))
586 break;
587 listpos = &next->entry;
590 list_add(&nt->entry, listpos);
592 if (listpos == head) {
594 * We are the new earliest-expiring timer.
595 * If we are a thread timer, there can always
596 * be a process timer telling us to stop earlier.
599 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
600 union cpu_time_count *exp = &nt->expires;
602 switch (CPUCLOCK_WHICH(timer->it_clock)) {
603 default:
604 BUG();
605 case CPUCLOCK_PROF:
606 if (expires_gt(p->cputime_expires.prof_exp,
607 exp->cpu))
608 p->cputime_expires.prof_exp = exp->cpu;
609 break;
610 case CPUCLOCK_VIRT:
611 if (expires_gt(p->cputime_expires.virt_exp,
612 exp->cpu))
613 p->cputime_expires.virt_exp = exp->cpu;
614 break;
615 case CPUCLOCK_SCHED:
616 if (p->cputime_expires.sched_exp == 0 ||
617 p->cputime_expires.sched_exp > exp->sched)
618 p->cputime_expires.sched_exp =
619 exp->sched;
620 break;
622 } else {
623 struct signal_struct *const sig = p->signal;
624 union cpu_time_count *exp = &timer->it.cpu.expires;
627 * For a process timer, set the cached expiration time.
629 switch (CPUCLOCK_WHICH(timer->it_clock)) {
630 default:
631 BUG();
632 case CPUCLOCK_VIRT:
633 if (expires_le(sig->it[CPUCLOCK_VIRT].expires,
634 exp->cpu))
635 break;
636 sig->cputime_expires.virt_exp = exp->cpu;
637 break;
638 case CPUCLOCK_PROF:
639 if (expires_le(sig->it[CPUCLOCK_PROF].expires,
640 exp->cpu))
641 break;
642 i = sig->rlim[RLIMIT_CPU].rlim_cur;
643 if (i != RLIM_INFINITY &&
644 i <= cputime_to_secs(exp->cpu))
645 break;
646 sig->cputime_expires.prof_exp = exp->cpu;
647 break;
648 case CPUCLOCK_SCHED:
649 sig->cputime_expires.sched_exp = exp->sched;
650 break;
655 spin_unlock(&p->sighand->siglock);
659 * The timer is locked, fire it and arrange for its reload.
661 static void cpu_timer_fire(struct k_itimer *timer)
663 if (unlikely(timer->sigq == NULL)) {
665 * This a special case for clock_nanosleep,
666 * not a normal timer from sys_timer_create.
668 wake_up_process(timer->it_process);
669 timer->it.cpu.expires.sched = 0;
670 } else if (timer->it.cpu.incr.sched == 0) {
672 * One-shot timer. Clear it as soon as it's fired.
674 posix_timer_event(timer, 0);
675 timer->it.cpu.expires.sched = 0;
676 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
678 * The signal did not get queued because the signal
679 * was ignored, so we won't get any callback to
680 * reload the timer. But we need to keep it
681 * ticking in case the signal is deliverable next time.
683 posix_cpu_timer_schedule(timer);
688 * Sample a process (thread group) timer for the given group_leader task.
689 * Must be called with tasklist_lock held for reading.
691 static int cpu_timer_sample_group(const clockid_t which_clock,
692 struct task_struct *p,
693 union cpu_time_count *cpu)
695 struct task_cputime cputime;
697 thread_group_cputimer(p, &cputime);
698 switch (CPUCLOCK_WHICH(which_clock)) {
699 default:
700 return -EINVAL;
701 case CPUCLOCK_PROF:
702 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
703 break;
704 case CPUCLOCK_VIRT:
705 cpu->cpu = cputime.utime;
706 break;
707 case CPUCLOCK_SCHED:
708 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
709 break;
711 return 0;
715 * Guts of sys_timer_settime for CPU timers.
716 * This is called with the timer locked and interrupts disabled.
717 * If we return TIMER_RETRY, it's necessary to release the timer's lock
718 * and try again. (This happens when the timer is in the middle of firing.)
720 int posix_cpu_timer_set(struct k_itimer *timer, int flags,
721 struct itimerspec *new, struct itimerspec *old)
723 struct task_struct *p = timer->it.cpu.task;
724 union cpu_time_count old_expires, new_expires, val;
725 int ret;
727 if (unlikely(p == NULL)) {
729 * Timer refers to a dead task's clock.
731 return -ESRCH;
734 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
736 read_lock(&tasklist_lock);
738 * We need the tasklist_lock to protect against reaping that
739 * clears p->signal. If p has just been reaped, we can no
740 * longer get any information about it at all.
742 if (unlikely(p->signal == NULL)) {
743 read_unlock(&tasklist_lock);
744 put_task_struct(p);
745 timer->it.cpu.task = NULL;
746 return -ESRCH;
750 * Disarm any old timer after extracting its expiry time.
752 BUG_ON(!irqs_disabled());
754 ret = 0;
755 spin_lock(&p->sighand->siglock);
756 old_expires = timer->it.cpu.expires;
757 if (unlikely(timer->it.cpu.firing)) {
758 timer->it.cpu.firing = -1;
759 ret = TIMER_RETRY;
760 } else
761 list_del_init(&timer->it.cpu.entry);
762 spin_unlock(&p->sighand->siglock);
765 * We need to sample the current value to convert the new
766 * value from to relative and absolute, and to convert the
767 * old value from absolute to relative. To set a process
768 * timer, we need a sample to balance the thread expiry
769 * times (in arm_timer). With an absolute time, we must
770 * check if it's already passed. In short, we need a sample.
772 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
773 cpu_clock_sample(timer->it_clock, p, &val);
774 } else {
775 cpu_timer_sample_group(timer->it_clock, p, &val);
778 if (old) {
779 if (old_expires.sched == 0) {
780 old->it_value.tv_sec = 0;
781 old->it_value.tv_nsec = 0;
782 } else {
784 * Update the timer in case it has
785 * overrun already. If it has,
786 * we'll report it as having overrun
787 * and with the next reloaded timer
788 * already ticking, though we are
789 * swallowing that pending
790 * notification here to install the
791 * new setting.
793 bump_cpu_timer(timer, val);
794 if (cpu_time_before(timer->it_clock, val,
795 timer->it.cpu.expires)) {
796 old_expires = cpu_time_sub(
797 timer->it_clock,
798 timer->it.cpu.expires, val);
799 sample_to_timespec(timer->it_clock,
800 old_expires,
801 &old->it_value);
802 } else {
803 old->it_value.tv_nsec = 1;
804 old->it_value.tv_sec = 0;
809 if (unlikely(ret)) {
811 * We are colliding with the timer actually firing.
812 * Punt after filling in the timer's old value, and
813 * disable this firing since we are already reporting
814 * it as an overrun (thanks to bump_cpu_timer above).
816 read_unlock(&tasklist_lock);
817 goto out;
820 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
821 cpu_time_add(timer->it_clock, &new_expires, val);
825 * Install the new expiry time (or zero).
826 * For a timer with no notification action, we don't actually
827 * arm the timer (we'll just fake it for timer_gettime).
829 timer->it.cpu.expires = new_expires;
830 if (new_expires.sched != 0 &&
831 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
832 cpu_time_before(timer->it_clock, val, new_expires)) {
833 arm_timer(timer, val);
836 read_unlock(&tasklist_lock);
839 * Install the new reload setting, and
840 * set up the signal and overrun bookkeeping.
842 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
843 &new->it_interval);
846 * This acts as a modification timestamp for the timer,
847 * so any automatic reload attempt will punt on seeing
848 * that we have reset the timer manually.
850 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
851 ~REQUEUE_PENDING;
852 timer->it_overrun_last = 0;
853 timer->it_overrun = -1;
855 if (new_expires.sched != 0 &&
856 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
857 !cpu_time_before(timer->it_clock, val, new_expires)) {
859 * The designated time already passed, so we notify
860 * immediately, even if the thread never runs to
861 * accumulate more time on this clock.
863 cpu_timer_fire(timer);
866 ret = 0;
867 out:
868 if (old) {
869 sample_to_timespec(timer->it_clock,
870 timer->it.cpu.incr, &old->it_interval);
872 return ret;
875 void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
877 union cpu_time_count now;
878 struct task_struct *p = timer->it.cpu.task;
879 int clear_dead;
882 * Easy part: convert the reload time.
884 sample_to_timespec(timer->it_clock,
885 timer->it.cpu.incr, &itp->it_interval);
887 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
888 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
889 return;
892 if (unlikely(p == NULL)) {
894 * This task already died and the timer will never fire.
895 * In this case, expires is actually the dead value.
897 dead:
898 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
899 &itp->it_value);
900 return;
904 * Sample the clock to take the difference with the expiry time.
906 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
907 cpu_clock_sample(timer->it_clock, p, &now);
908 clear_dead = p->exit_state;
909 } else {
910 read_lock(&tasklist_lock);
911 if (unlikely(p->signal == NULL)) {
913 * The process has been reaped.
914 * We can't even collect a sample any more.
915 * Call the timer disarmed, nothing else to do.
917 put_task_struct(p);
918 timer->it.cpu.task = NULL;
919 timer->it.cpu.expires.sched = 0;
920 read_unlock(&tasklist_lock);
921 goto dead;
922 } else {
923 cpu_timer_sample_group(timer->it_clock, p, &now);
924 clear_dead = (unlikely(p->exit_state) &&
925 thread_group_empty(p));
927 read_unlock(&tasklist_lock);
930 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
931 if (timer->it.cpu.incr.sched == 0 &&
932 cpu_time_before(timer->it_clock,
933 timer->it.cpu.expires, now)) {
935 * Do-nothing timer expired and has no reload,
936 * so it's as if it was never set.
938 timer->it.cpu.expires.sched = 0;
939 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
940 return;
943 * Account for any expirations and reloads that should
944 * have happened.
946 bump_cpu_timer(timer, now);
949 if (unlikely(clear_dead)) {
951 * We've noticed that the thread is dead, but
952 * not yet reaped. Take this opportunity to
953 * drop our task ref.
955 clear_dead_task(timer, now);
956 goto dead;
959 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
960 sample_to_timespec(timer->it_clock,
961 cpu_time_sub(timer->it_clock,
962 timer->it.cpu.expires, now),
963 &itp->it_value);
964 } else {
966 * The timer should have expired already, but the firing
967 * hasn't taken place yet. Say it's just about to expire.
969 itp->it_value.tv_nsec = 1;
970 itp->it_value.tv_sec = 0;
975 * Check for any per-thread CPU timers that have fired and move them off
976 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
977 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
979 static void check_thread_timers(struct task_struct *tsk,
980 struct list_head *firing)
982 int maxfire;
983 struct list_head *timers = tsk->cpu_timers;
984 struct signal_struct *const sig = tsk->signal;
986 maxfire = 20;
987 tsk->cputime_expires.prof_exp = cputime_zero;
988 while (!list_empty(timers)) {
989 struct cpu_timer_list *t = list_first_entry(timers,
990 struct cpu_timer_list,
991 entry);
992 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
993 tsk->cputime_expires.prof_exp = t->expires.cpu;
994 break;
996 t->firing = 1;
997 list_move_tail(&t->entry, firing);
1000 ++timers;
1001 maxfire = 20;
1002 tsk->cputime_expires.virt_exp = cputime_zero;
1003 while (!list_empty(timers)) {
1004 struct cpu_timer_list *t = list_first_entry(timers,
1005 struct cpu_timer_list,
1006 entry);
1007 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
1008 tsk->cputime_expires.virt_exp = t->expires.cpu;
1009 break;
1011 t->firing = 1;
1012 list_move_tail(&t->entry, firing);
1015 ++timers;
1016 maxfire = 20;
1017 tsk->cputime_expires.sched_exp = 0;
1018 while (!list_empty(timers)) {
1019 struct cpu_timer_list *t = list_first_entry(timers,
1020 struct cpu_timer_list,
1021 entry);
1022 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
1023 tsk->cputime_expires.sched_exp = t->expires.sched;
1024 break;
1026 t->firing = 1;
1027 list_move_tail(&t->entry, firing);
1031 * Check for the special case thread timers.
1033 if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
1034 unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
1035 unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
1037 if (hard != RLIM_INFINITY &&
1038 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
1040 * At the hard limit, we just die.
1041 * No need to calculate anything else now.
1043 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1044 return;
1046 if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
1048 * At the soft limit, send a SIGXCPU every second.
1050 if (sig->rlim[RLIMIT_RTTIME].rlim_cur
1051 < sig->rlim[RLIMIT_RTTIME].rlim_max) {
1052 sig->rlim[RLIMIT_RTTIME].rlim_cur +=
1053 USEC_PER_SEC;
1055 printk(KERN_INFO
1056 "RT Watchdog Timeout: %s[%d]\n",
1057 tsk->comm, task_pid_nr(tsk));
1058 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1063 static void stop_process_timers(struct task_struct *tsk)
1065 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
1066 unsigned long flags;
1068 if (!cputimer->running)
1069 return;
1071 spin_lock_irqsave(&cputimer->lock, flags);
1072 cputimer->running = 0;
1073 spin_unlock_irqrestore(&cputimer->lock, flags);
1076 static u32 onecputick;
1078 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
1079 cputime_t *expires, cputime_t cur_time, int signo)
1081 if (cputime_eq(it->expires, cputime_zero))
1082 return;
1084 if (cputime_ge(cur_time, it->expires)) {
1085 if (!cputime_eq(it->incr, cputime_zero)) {
1086 it->expires = cputime_add(it->expires, it->incr);
1087 it->error += it->incr_error;
1088 if (it->error >= onecputick) {
1089 it->expires = cputime_sub(it->expires,
1090 cputime_one_jiffy);
1091 it->error -= onecputick;
1093 } else {
1094 it->expires = cputime_zero;
1097 trace_itimer_expire(signo == SIGPROF ?
1098 ITIMER_PROF : ITIMER_VIRTUAL,
1099 tsk->signal->leader_pid, cur_time);
1100 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
1103 if (!cputime_eq(it->expires, cputime_zero) &&
1104 (cputime_eq(*expires, cputime_zero) ||
1105 cputime_lt(it->expires, *expires))) {
1106 *expires = it->expires;
1111 * Check for any per-thread CPU timers that have fired and move them
1112 * off the tsk->*_timers list onto the firing list. Per-thread timers
1113 * have already been taken off.
1115 static void check_process_timers(struct task_struct *tsk,
1116 struct list_head *firing)
1118 int maxfire;
1119 struct signal_struct *const sig = tsk->signal;
1120 cputime_t utime, ptime, virt_expires, prof_expires;
1121 unsigned long long sum_sched_runtime, sched_expires;
1122 struct list_head *timers = sig->cpu_timers;
1123 struct task_cputime cputime;
1126 * Don't sample the current process CPU clocks if there are no timers.
1128 if (list_empty(&timers[CPUCLOCK_PROF]) &&
1129 cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) &&
1130 sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
1131 list_empty(&timers[CPUCLOCK_VIRT]) &&
1132 cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) &&
1133 list_empty(&timers[CPUCLOCK_SCHED])) {
1134 stop_process_timers(tsk);
1135 return;
1139 * Collect the current process totals.
1141 thread_group_cputimer(tsk, &cputime);
1142 utime = cputime.utime;
1143 ptime = cputime_add(utime, cputime.stime);
1144 sum_sched_runtime = cputime.sum_exec_runtime;
1145 maxfire = 20;
1146 prof_expires = cputime_zero;
1147 while (!list_empty(timers)) {
1148 struct cpu_timer_list *tl = list_first_entry(timers,
1149 struct cpu_timer_list,
1150 entry);
1151 if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
1152 prof_expires = tl->expires.cpu;
1153 break;
1155 tl->firing = 1;
1156 list_move_tail(&tl->entry, firing);
1159 ++timers;
1160 maxfire = 20;
1161 virt_expires = cputime_zero;
1162 while (!list_empty(timers)) {
1163 struct cpu_timer_list *tl = list_first_entry(timers,
1164 struct cpu_timer_list,
1165 entry);
1166 if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
1167 virt_expires = tl->expires.cpu;
1168 break;
1170 tl->firing = 1;
1171 list_move_tail(&tl->entry, firing);
1174 ++timers;
1175 maxfire = 20;
1176 sched_expires = 0;
1177 while (!list_empty(timers)) {
1178 struct cpu_timer_list *tl = list_first_entry(timers,
1179 struct cpu_timer_list,
1180 entry);
1181 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1182 sched_expires = tl->expires.sched;
1183 break;
1185 tl->firing = 1;
1186 list_move_tail(&tl->entry, firing);
1190 * Check for the special case process timers.
1192 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
1193 SIGPROF);
1194 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
1195 SIGVTALRM);
1197 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
1198 unsigned long psecs = cputime_to_secs(ptime);
1199 cputime_t x;
1200 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
1202 * At the hard limit, we just die.
1203 * No need to calculate anything else now.
1205 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1206 return;
1208 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
1210 * At the soft limit, send a SIGXCPU every second.
1212 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1213 if (sig->rlim[RLIMIT_CPU].rlim_cur
1214 < sig->rlim[RLIMIT_CPU].rlim_max) {
1215 sig->rlim[RLIMIT_CPU].rlim_cur++;
1218 x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
1219 if (cputime_eq(prof_expires, cputime_zero) ||
1220 cputime_lt(x, prof_expires)) {
1221 prof_expires = x;
1225 if (!cputime_eq(prof_expires, cputime_zero) &&
1226 (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
1227 cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
1228 sig->cputime_expires.prof_exp = prof_expires;
1229 if (!cputime_eq(virt_expires, cputime_zero) &&
1230 (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
1231 cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
1232 sig->cputime_expires.virt_exp = virt_expires;
1233 if (sched_expires != 0 &&
1234 (sig->cputime_expires.sched_exp == 0 ||
1235 sig->cputime_expires.sched_exp > sched_expires))
1236 sig->cputime_expires.sched_exp = sched_expires;
1240 * This is called from the signal code (via do_schedule_next_timer)
1241 * when the last timer signal was delivered and we have to reload the timer.
1243 void posix_cpu_timer_schedule(struct k_itimer *timer)
1245 struct task_struct *p = timer->it.cpu.task;
1246 union cpu_time_count now;
1248 if (unlikely(p == NULL))
1250 * The task was cleaned up already, no future firings.
1252 goto out;
1255 * Fetch the current sample and update the timer's expiry time.
1257 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1258 cpu_clock_sample(timer->it_clock, p, &now);
1259 bump_cpu_timer(timer, now);
1260 if (unlikely(p->exit_state)) {
1261 clear_dead_task(timer, now);
1262 goto out;
1264 read_lock(&tasklist_lock); /* arm_timer needs it. */
1265 } else {
1266 read_lock(&tasklist_lock);
1267 if (unlikely(p->signal == NULL)) {
1269 * The process has been reaped.
1270 * We can't even collect a sample any more.
1272 put_task_struct(p);
1273 timer->it.cpu.task = p = NULL;
1274 timer->it.cpu.expires.sched = 0;
1275 goto out_unlock;
1276 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1278 * We've noticed that the thread is dead, but
1279 * not yet reaped. Take this opportunity to
1280 * drop our task ref.
1282 clear_dead_task(timer, now);
1283 goto out_unlock;
1285 cpu_timer_sample_group(timer->it_clock, p, &now);
1286 bump_cpu_timer(timer, now);
1287 /* Leave the tasklist_lock locked for the call below. */
1291 * Now re-arm for the new expiry time.
1293 arm_timer(timer, now);
1295 out_unlock:
1296 read_unlock(&tasklist_lock);
1298 out:
1299 timer->it_overrun_last = timer->it_overrun;
1300 timer->it_overrun = -1;
1301 ++timer->it_requeue_pending;
1305 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1307 * @cputime: The struct to compare.
1309 * Checks @cputime to see if all fields are zero. Returns true if all fields
1310 * are zero, false if any field is nonzero.
1312 static inline int task_cputime_zero(const struct task_cputime *cputime)
1314 if (cputime_eq(cputime->utime, cputime_zero) &&
1315 cputime_eq(cputime->stime, cputime_zero) &&
1316 cputime->sum_exec_runtime == 0)
1317 return 1;
1318 return 0;
1322 * task_cputime_expired - Compare two task_cputime entities.
1324 * @sample: The task_cputime structure to be checked for expiration.
1325 * @expires: Expiration times, against which @sample will be checked.
1327 * Checks @sample against @expires to see if any field of @sample has expired.
1328 * Returns true if any field of the former is greater than the corresponding
1329 * field of the latter if the latter field is set. Otherwise returns false.
1331 static inline int task_cputime_expired(const struct task_cputime *sample,
1332 const struct task_cputime *expires)
1334 if (!cputime_eq(expires->utime, cputime_zero) &&
1335 cputime_ge(sample->utime, expires->utime))
1336 return 1;
1337 if (!cputime_eq(expires->stime, cputime_zero) &&
1338 cputime_ge(cputime_add(sample->utime, sample->stime),
1339 expires->stime))
1340 return 1;
1341 if (expires->sum_exec_runtime != 0 &&
1342 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1343 return 1;
1344 return 0;
1348 * fastpath_timer_check - POSIX CPU timers fast path.
1350 * @tsk: The task (thread) being checked.
1352 * Check the task and thread group timers. If both are zero (there are no
1353 * timers set) return false. Otherwise snapshot the task and thread group
1354 * timers and compare them with the corresponding expiration times. Return
1355 * true if a timer has expired, else return false.
1357 static inline int fastpath_timer_check(struct task_struct *tsk)
1359 struct signal_struct *sig;
1361 /* tsk == current, ensure it is safe to use ->signal/sighand */
1362 if (unlikely(tsk->exit_state))
1363 return 0;
1365 if (!task_cputime_zero(&tsk->cputime_expires)) {
1366 struct task_cputime task_sample = {
1367 .utime = tsk->utime,
1368 .stime = tsk->stime,
1369 .sum_exec_runtime = tsk->se.sum_exec_runtime
1372 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1373 return 1;
1376 sig = tsk->signal;
1377 if (!task_cputime_zero(&sig->cputime_expires)) {
1378 struct task_cputime group_sample;
1380 thread_group_cputimer(tsk, &group_sample);
1381 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1382 return 1;
1385 return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
1389 * This is called from the timer interrupt handler. The irq handler has
1390 * already updated our counts. We need to check if any timers fire now.
1391 * Interrupts are disabled.
1393 void run_posix_cpu_timers(struct task_struct *tsk)
1395 LIST_HEAD(firing);
1396 struct k_itimer *timer, *next;
1398 BUG_ON(!irqs_disabled());
1401 * The fast path checks that there are no expired thread or thread
1402 * group timers. If that's so, just return.
1404 if (!fastpath_timer_check(tsk))
1405 return;
1407 spin_lock(&tsk->sighand->siglock);
1409 * Here we take off tsk->signal->cpu_timers[N] and
1410 * tsk->cpu_timers[N] all the timers that are firing, and
1411 * put them on the firing list.
1413 check_thread_timers(tsk, &firing);
1414 check_process_timers(tsk, &firing);
1417 * We must release these locks before taking any timer's lock.
1418 * There is a potential race with timer deletion here, as the
1419 * siglock now protects our private firing list. We have set
1420 * the firing flag in each timer, so that a deletion attempt
1421 * that gets the timer lock before we do will give it up and
1422 * spin until we've taken care of that timer below.
1424 spin_unlock(&tsk->sighand->siglock);
1427 * Now that all the timers on our list have the firing flag,
1428 * noone will touch their list entries but us. We'll take
1429 * each timer's lock before clearing its firing flag, so no
1430 * timer call will interfere.
1432 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1433 int cpu_firing;
1435 spin_lock(&timer->it_lock);
1436 list_del_init(&timer->it.cpu.entry);
1437 cpu_firing = timer->it.cpu.firing;
1438 timer->it.cpu.firing = 0;
1440 * The firing flag is -1 if we collided with a reset
1441 * of the timer, which already reported this
1442 * almost-firing as an overrun. So don't generate an event.
1444 if (likely(cpu_firing >= 0))
1445 cpu_timer_fire(timer);
1446 spin_unlock(&timer->it_lock);
1451 * Set one of the process-wide special case CPU timers.
1452 * The tsk->sighand->siglock must be held by the caller.
1453 * The *newval argument is relative and we update it to be absolute, *oldval
1454 * is absolute and we update it to be relative.
1456 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1457 cputime_t *newval, cputime_t *oldval)
1459 union cpu_time_count now;
1460 struct list_head *head;
1462 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1463 cpu_timer_sample_group(clock_idx, tsk, &now);
1465 if (oldval) {
1466 if (!cputime_eq(*oldval, cputime_zero)) {
1467 if (cputime_le(*oldval, now.cpu)) {
1468 /* Just about to fire. */
1469 *oldval = cputime_one_jiffy;
1470 } else {
1471 *oldval = cputime_sub(*oldval, now.cpu);
1475 if (cputime_eq(*newval, cputime_zero))
1476 return;
1477 *newval = cputime_add(*newval, now.cpu);
1480 * If the RLIMIT_CPU timer will expire before the
1481 * ITIMER_PROF timer, we have nothing else to do.
1483 if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
1484 < cputime_to_secs(*newval))
1485 return;
1489 * Check whether there are any process timers already set to fire
1490 * before this one. If so, we don't have anything more to do.
1492 head = &tsk->signal->cpu_timers[clock_idx];
1493 if (list_empty(head) ||
1494 cputime_ge(list_first_entry(head,
1495 struct cpu_timer_list, entry)->expires.cpu,
1496 *newval)) {
1497 switch (clock_idx) {
1498 case CPUCLOCK_PROF:
1499 tsk->signal->cputime_expires.prof_exp = *newval;
1500 break;
1501 case CPUCLOCK_VIRT:
1502 tsk->signal->cputime_expires.virt_exp = *newval;
1503 break;
1508 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1509 struct timespec *rqtp, struct itimerspec *it)
1511 struct k_itimer timer;
1512 int error;
1515 * Set up a temporary timer and then wait for it to go off.
1517 memset(&timer, 0, sizeof timer);
1518 spin_lock_init(&timer.it_lock);
1519 timer.it_clock = which_clock;
1520 timer.it_overrun = -1;
1521 error = posix_cpu_timer_create(&timer);
1522 timer.it_process = current;
1523 if (!error) {
1524 static struct itimerspec zero_it;
1526 memset(it, 0, sizeof *it);
1527 it->it_value = *rqtp;
1529 spin_lock_irq(&timer.it_lock);
1530 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1531 if (error) {
1532 spin_unlock_irq(&timer.it_lock);
1533 return error;
1536 while (!signal_pending(current)) {
1537 if (timer.it.cpu.expires.sched == 0) {
1539 * Our timer fired and was reset.
1541 spin_unlock_irq(&timer.it_lock);
1542 return 0;
1546 * Block until cpu_timer_fire (or a signal) wakes us.
1548 __set_current_state(TASK_INTERRUPTIBLE);
1549 spin_unlock_irq(&timer.it_lock);
1550 schedule();
1551 spin_lock_irq(&timer.it_lock);
1555 * We were interrupted by a signal.
1557 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1558 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1559 spin_unlock_irq(&timer.it_lock);
1561 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1563 * It actually did fire already.
1565 return 0;
1568 error = -ERESTART_RESTARTBLOCK;
1571 return error;
1574 int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1575 struct timespec *rqtp, struct timespec __user *rmtp)
1577 struct restart_block *restart_block =
1578 &current_thread_info()->restart_block;
1579 struct itimerspec it;
1580 int error;
1583 * Diagnose required errors first.
1585 if (CPUCLOCK_PERTHREAD(which_clock) &&
1586 (CPUCLOCK_PID(which_clock) == 0 ||
1587 CPUCLOCK_PID(which_clock) == current->pid))
1588 return -EINVAL;
1590 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1592 if (error == -ERESTART_RESTARTBLOCK) {
1594 if (flags & TIMER_ABSTIME)
1595 return -ERESTARTNOHAND;
1597 * Report back to the user the time still remaining.
1599 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1600 return -EFAULT;
1602 restart_block->fn = posix_cpu_nsleep_restart;
1603 restart_block->arg0 = which_clock;
1604 restart_block->arg1 = (unsigned long) rmtp;
1605 restart_block->arg2 = rqtp->tv_sec;
1606 restart_block->arg3 = rqtp->tv_nsec;
1608 return error;
1611 long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1613 clockid_t which_clock = restart_block->arg0;
1614 struct timespec __user *rmtp;
1615 struct timespec t;
1616 struct itimerspec it;
1617 int error;
1619 rmtp = (struct timespec __user *) restart_block->arg1;
1620 t.tv_sec = restart_block->arg2;
1621 t.tv_nsec = restart_block->arg3;
1623 restart_block->fn = do_no_restart_syscall;
1624 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1626 if (error == -ERESTART_RESTARTBLOCK) {
1628 * Report back to the user the time still remaining.
1630 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1631 return -EFAULT;
1633 restart_block->fn = posix_cpu_nsleep_restart;
1634 restart_block->arg0 = which_clock;
1635 restart_block->arg1 = (unsigned long) rmtp;
1636 restart_block->arg2 = t.tv_sec;
1637 restart_block->arg3 = t.tv_nsec;
1639 return error;
1644 #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1645 #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1647 static int process_cpu_clock_getres(const clockid_t which_clock,
1648 struct timespec *tp)
1650 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1652 static int process_cpu_clock_get(const clockid_t which_clock,
1653 struct timespec *tp)
1655 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1657 static int process_cpu_timer_create(struct k_itimer *timer)
1659 timer->it_clock = PROCESS_CLOCK;
1660 return posix_cpu_timer_create(timer);
1662 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1663 struct timespec *rqtp,
1664 struct timespec __user *rmtp)
1666 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1668 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1670 return -EINVAL;
1672 static int thread_cpu_clock_getres(const clockid_t which_clock,
1673 struct timespec *tp)
1675 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1677 static int thread_cpu_clock_get(const clockid_t which_clock,
1678 struct timespec *tp)
1680 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1682 static int thread_cpu_timer_create(struct k_itimer *timer)
1684 timer->it_clock = THREAD_CLOCK;
1685 return posix_cpu_timer_create(timer);
1687 static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
1688 struct timespec *rqtp, struct timespec __user *rmtp)
1690 return -EINVAL;
1692 static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
1694 return -EINVAL;
1697 static __init int init_posix_cpu_timers(void)
1699 struct k_clock process = {
1700 .clock_getres = process_cpu_clock_getres,
1701 .clock_get = process_cpu_clock_get,
1702 .clock_set = do_posix_clock_nosettime,
1703 .timer_create = process_cpu_timer_create,
1704 .nsleep = process_cpu_nsleep,
1705 .nsleep_restart = process_cpu_nsleep_restart,
1707 struct k_clock thread = {
1708 .clock_getres = thread_cpu_clock_getres,
1709 .clock_get = thread_cpu_clock_get,
1710 .clock_set = do_posix_clock_nosettime,
1711 .timer_create = thread_cpu_timer_create,
1712 .nsleep = thread_cpu_nsleep,
1713 .nsleep_restart = thread_cpu_nsleep_restart,
1715 struct timespec ts;
1717 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1718 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1720 cputime_to_timespec(cputime_one_jiffy, &ts);
1721 onecputick = ts.tv_nsec;
1722 WARN_ON(ts.tv_sec != 0);
1724 return 0;
1726 __initcall(init_posix_cpu_timers);