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[linux-2.6/linux-acpi-2.6.git] / kernel / posix-cpu-timers.c
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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>
13 * Called after updating RLIMIT_CPU to set timer expiration if necessary.
15 void update_rlimit_cpu(unsigned long rlim_new)
17 cputime_t cputime;
19 cputime = secs_to_cputime(rlim_new);
20 if (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
21 cputime_gt(current->signal->it_prof_expires, cputime)) {
22 spin_lock_irq(&current->sighand->siglock);
23 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
24 spin_unlock_irq(&current->sighand->siglock);
28 static int check_clock(const clockid_t which_clock)
30 int error = 0;
31 struct task_struct *p;
32 const pid_t pid = CPUCLOCK_PID(which_clock);
34 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
35 return -EINVAL;
37 if (pid == 0)
38 return 0;
40 read_lock(&tasklist_lock);
41 p = find_task_by_vpid(pid);
42 if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
43 same_thread_group(p, current) : thread_group_leader(p))) {
44 error = -EINVAL;
46 read_unlock(&tasklist_lock);
48 return error;
51 static inline union cpu_time_count
52 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
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);
61 return ret;
64 static void sample_to_timespec(const clockid_t which_clock,
65 union cpu_time_count cpu,
66 struct timespec *tp)
68 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
69 *tp = ns_to_timespec(cpu.sched);
70 else
71 cputime_to_timespec(cpu.cpu, tp);
74 static inline int cpu_time_before(const clockid_t which_clock,
75 union cpu_time_count now,
76 union cpu_time_count then)
78 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
79 return now.sched < then.sched;
80 } else {
81 return cputime_lt(now.cpu, then.cpu);
84 static inline void cpu_time_add(const clockid_t which_clock,
85 union cpu_time_count *acc,
86 union cpu_time_count val)
88 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
89 acc->sched += val.sched;
90 } else {
91 acc->cpu = cputime_add(acc->cpu, val.cpu);
94 static 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)
98 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
99 a.sched -= b.sched;
100 } else {
101 a.cpu = cputime_sub(a.cpu, b.cpu);
103 return a;
107 * Divide and limit the result to res >= 1
109 * This is necessary to prevent signal delivery starvation, when the result of
110 * the division would be rounded down to 0.
112 static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
114 cputime_t res = cputime_div(time, div);
116 return max_t(cputime_t, res, 1);
120 * Update expiry time from increment, and increase overrun count,
121 * given the current clock sample.
123 static void bump_cpu_timer(struct k_itimer *timer,
124 union cpu_time_count now)
126 int i;
128 if (timer->it.cpu.incr.sched == 0)
129 return;
131 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
132 unsigned long long delta, incr;
134 if (now.sched < timer->it.cpu.expires.sched)
135 return;
136 incr = timer->it.cpu.incr.sched;
137 delta = now.sched + incr - timer->it.cpu.expires.sched;
138 /* Don't use (incr*2 < delta), incr*2 might overflow. */
139 for (i = 0; incr < delta - incr; i++)
140 incr = incr << 1;
141 for (; i >= 0; incr >>= 1, i--) {
142 if (delta < incr)
143 continue;
144 timer->it.cpu.expires.sched += incr;
145 timer->it_overrun += 1 << i;
146 delta -= incr;
148 } else {
149 cputime_t delta, incr;
151 if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
152 return;
153 incr = timer->it.cpu.incr.cpu;
154 delta = cputime_sub(cputime_add(now.cpu, incr),
155 timer->it.cpu.expires.cpu);
156 /* Don't use (incr*2 < delta), incr*2 might overflow. */
157 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
158 incr = cputime_add(incr, incr);
159 for (; i >= 0; incr = cputime_halve(incr), i--) {
160 if (cputime_lt(delta, incr))
161 continue;
162 timer->it.cpu.expires.cpu =
163 cputime_add(timer->it.cpu.expires.cpu, incr);
164 timer->it_overrun += 1 << i;
165 delta = cputime_sub(delta, incr);
170 static inline cputime_t prof_ticks(struct task_struct *p)
172 return cputime_add(p->utime, p->stime);
174 static inline cputime_t virt_ticks(struct task_struct *p)
176 return p->utime;
179 int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
181 int error = check_clock(which_clock);
182 if (!error) {
183 tp->tv_sec = 0;
184 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
185 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
187 * If sched_clock is using a cycle counter, we
188 * don't have any idea of its true resolution
189 * exported, but it is much more than 1s/HZ.
191 tp->tv_nsec = 1;
194 return error;
197 int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
200 * You can never reset a CPU clock, but we check for other errors
201 * in the call before failing with EPERM.
203 int error = check_clock(which_clock);
204 if (error == 0) {
205 error = -EPERM;
207 return error;
212 * Sample a per-thread clock for the given task.
214 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
215 union cpu_time_count *cpu)
217 switch (CPUCLOCK_WHICH(which_clock)) {
218 default:
219 return -EINVAL;
220 case CPUCLOCK_PROF:
221 cpu->cpu = prof_ticks(p);
222 break;
223 case CPUCLOCK_VIRT:
224 cpu->cpu = virt_ticks(p);
225 break;
226 case CPUCLOCK_SCHED:
227 cpu->sched = task_sched_runtime(p);
228 break;
230 return 0;
233 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
235 struct sighand_struct *sighand;
236 struct signal_struct *sig;
237 struct task_struct *t;
239 *times = INIT_CPUTIME;
241 rcu_read_lock();
242 sighand = rcu_dereference(tsk->sighand);
243 if (!sighand)
244 goto out;
246 sig = tsk->signal;
248 t = tsk;
249 do {
250 times->utime = cputime_add(times->utime, t->utime);
251 times->stime = cputime_add(times->stime, t->stime);
252 times->sum_exec_runtime += t->se.sum_exec_runtime;
254 t = next_thread(t);
255 } while (t != tsk);
257 times->utime = cputime_add(times->utime, sig->utime);
258 times->stime = cputime_add(times->stime, sig->stime);
259 times->sum_exec_runtime += sig->sum_sched_runtime;
260 out:
261 rcu_read_unlock();
264 static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
266 if (cputime_gt(b->utime, a->utime))
267 a->utime = b->utime;
269 if (cputime_gt(b->stime, a->stime))
270 a->stime = b->stime;
272 if (b->sum_exec_runtime > a->sum_exec_runtime)
273 a->sum_exec_runtime = b->sum_exec_runtime;
276 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
278 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
279 struct task_cputime sum;
280 unsigned long flags;
282 spin_lock_irqsave(&cputimer->lock, flags);
283 if (!cputimer->running) {
284 cputimer->running = 1;
286 * The POSIX timer interface allows for absolute time expiry
287 * values through the TIMER_ABSTIME flag, therefore we have
288 * to synchronize the timer to the clock every time we start
289 * it.
291 thread_group_cputime(tsk, &sum);
292 update_gt_cputime(&cputimer->cputime, &sum);
294 *times = cputimer->cputime;
295 spin_unlock_irqrestore(&cputimer->lock, flags);
299 * Sample a process (thread group) clock for the given group_leader task.
300 * Must be called with tasklist_lock held for reading.
302 static int cpu_clock_sample_group(const clockid_t which_clock,
303 struct task_struct *p,
304 union cpu_time_count *cpu)
306 struct task_cputime cputime;
308 switch (CPUCLOCK_WHICH(which_clock)) {
309 default:
310 return -EINVAL;
311 case CPUCLOCK_PROF:
312 thread_group_cputime(p, &cputime);
313 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
314 break;
315 case CPUCLOCK_VIRT:
316 thread_group_cputime(p, &cputime);
317 cpu->cpu = cputime.utime;
318 break;
319 case CPUCLOCK_SCHED:
320 cpu->sched = thread_group_sched_runtime(p);
321 break;
323 return 0;
327 int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
329 const pid_t pid = CPUCLOCK_PID(which_clock);
330 int error = -EINVAL;
331 union cpu_time_count rtn;
333 if (pid == 0) {
335 * Special case constant value for our own clocks.
336 * We don't have to do any lookup to find ourselves.
338 if (CPUCLOCK_PERTHREAD(which_clock)) {
340 * Sampling just ourselves we can do with no locking.
342 error = cpu_clock_sample(which_clock,
343 current, &rtn);
344 } else {
345 read_lock(&tasklist_lock);
346 error = cpu_clock_sample_group(which_clock,
347 current, &rtn);
348 read_unlock(&tasklist_lock);
350 } else {
352 * Find the given PID, and validate that the caller
353 * should be able to see it.
355 struct task_struct *p;
356 rcu_read_lock();
357 p = find_task_by_vpid(pid);
358 if (p) {
359 if (CPUCLOCK_PERTHREAD(which_clock)) {
360 if (same_thread_group(p, current)) {
361 error = cpu_clock_sample(which_clock,
362 p, &rtn);
364 } else {
365 read_lock(&tasklist_lock);
366 if (thread_group_leader(p) && p->signal) {
367 error =
368 cpu_clock_sample_group(which_clock,
369 p, &rtn);
371 read_unlock(&tasklist_lock);
374 rcu_read_unlock();
377 if (error)
378 return error;
379 sample_to_timespec(which_clock, rtn, tp);
380 return 0;
385 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
386 * This is called from sys_timer_create with the new timer already locked.
388 int posix_cpu_timer_create(struct k_itimer *new_timer)
390 int ret = 0;
391 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
392 struct task_struct *p;
394 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
395 return -EINVAL;
397 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
398 new_timer->it.cpu.incr.sched = 0;
399 new_timer->it.cpu.expires.sched = 0;
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 task_cputime cputime;
526 thread_group_cputimer(tsk, &cputime);
527 cleanup_timers(tsk->signal->cpu_timers,
528 cputime.utime, cputime.stime, cputime.sum_exec_runtime);
531 static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
534 * That's all for this thread or process.
535 * We leave our residual in expires to be reported.
537 put_task_struct(timer->it.cpu.task);
538 timer->it.cpu.task = NULL;
539 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
540 timer->it.cpu.expires,
541 now);
545 * Insert the timer on the appropriate list before any timers that
546 * expire later. This must be called with the tasklist_lock held
547 * for reading, and interrupts disabled.
549 static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
551 struct task_struct *p = timer->it.cpu.task;
552 struct list_head *head, *listpos;
553 struct cpu_timer_list *const nt = &timer->it.cpu;
554 struct cpu_timer_list *next;
555 unsigned long i;
557 head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
558 p->cpu_timers : p->signal->cpu_timers);
559 head += CPUCLOCK_WHICH(timer->it_clock);
561 BUG_ON(!irqs_disabled());
562 spin_lock(&p->sighand->siglock);
564 listpos = head;
565 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
566 list_for_each_entry(next, head, entry) {
567 if (next->expires.sched > nt->expires.sched)
568 break;
569 listpos = &next->entry;
571 } else {
572 list_for_each_entry(next, head, entry) {
573 if (cputime_gt(next->expires.cpu, nt->expires.cpu))
574 break;
575 listpos = &next->entry;
578 list_add(&nt->entry, listpos);
580 if (listpos == head) {
582 * We are the new earliest-expiring timer.
583 * If we are a thread timer, there can always
584 * be a process timer telling us to stop earlier.
587 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
588 switch (CPUCLOCK_WHICH(timer->it_clock)) {
589 default:
590 BUG();
591 case CPUCLOCK_PROF:
592 if (cputime_eq(p->cputime_expires.prof_exp,
593 cputime_zero) ||
594 cputime_gt(p->cputime_expires.prof_exp,
595 nt->expires.cpu))
596 p->cputime_expires.prof_exp =
597 nt->expires.cpu;
598 break;
599 case CPUCLOCK_VIRT:
600 if (cputime_eq(p->cputime_expires.virt_exp,
601 cputime_zero) ||
602 cputime_gt(p->cputime_expires.virt_exp,
603 nt->expires.cpu))
604 p->cputime_expires.virt_exp =
605 nt->expires.cpu;
606 break;
607 case CPUCLOCK_SCHED:
608 if (p->cputime_expires.sched_exp == 0 ||
609 p->cputime_expires.sched_exp >
610 nt->expires.sched)
611 p->cputime_expires.sched_exp =
612 nt->expires.sched;
613 break;
615 } else {
617 * For a process timer, set the cached expiration time.
619 switch (CPUCLOCK_WHICH(timer->it_clock)) {
620 default:
621 BUG();
622 case CPUCLOCK_VIRT:
623 if (!cputime_eq(p->signal->it_virt_expires,
624 cputime_zero) &&
625 cputime_lt(p->signal->it_virt_expires,
626 timer->it.cpu.expires.cpu))
627 break;
628 p->signal->cputime_expires.virt_exp =
629 timer->it.cpu.expires.cpu;
630 break;
631 case CPUCLOCK_PROF:
632 if (!cputime_eq(p->signal->it_prof_expires,
633 cputime_zero) &&
634 cputime_lt(p->signal->it_prof_expires,
635 timer->it.cpu.expires.cpu))
636 break;
637 i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
638 if (i != RLIM_INFINITY &&
639 i <= cputime_to_secs(timer->it.cpu.expires.cpu))
640 break;
641 p->signal->cputime_expires.prof_exp =
642 timer->it.cpu.expires.cpu;
643 break;
644 case CPUCLOCK_SCHED:
645 p->signal->cputime_expires.sched_exp =
646 timer->it.cpu.expires.sched;
647 break;
652 spin_unlock(&p->sighand->siglock);
656 * The timer is locked, fire it and arrange for its reload.
658 static void cpu_timer_fire(struct k_itimer *timer)
660 if (unlikely(timer->sigq == NULL)) {
662 * This a special case for clock_nanosleep,
663 * not a normal timer from sys_timer_create.
665 wake_up_process(timer->it_process);
666 timer->it.cpu.expires.sched = 0;
667 } else if (timer->it.cpu.incr.sched == 0) {
669 * One-shot timer. Clear it as soon as it's fired.
671 posix_timer_event(timer, 0);
672 timer->it.cpu.expires.sched = 0;
673 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
675 * The signal did not get queued because the signal
676 * was ignored, so we won't get any callback to
677 * reload the timer. But we need to keep it
678 * ticking in case the signal is deliverable next time.
680 posix_cpu_timer_schedule(timer);
685 * Sample a process (thread group) timer for the given group_leader task.
686 * Must be called with tasklist_lock held for reading.
688 static int cpu_timer_sample_group(const clockid_t which_clock,
689 struct task_struct *p,
690 union cpu_time_count *cpu)
692 struct task_cputime cputime;
694 thread_group_cputimer(p, &cputime);
695 switch (CPUCLOCK_WHICH(which_clock)) {
696 default:
697 return -EINVAL;
698 case CPUCLOCK_PROF:
699 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
700 break;
701 case CPUCLOCK_VIRT:
702 cpu->cpu = cputime.utime;
703 break;
704 case CPUCLOCK_SCHED:
705 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
706 break;
708 return 0;
712 * Guts of sys_timer_settime for CPU timers.
713 * This is called with the timer locked and interrupts disabled.
714 * If we return TIMER_RETRY, it's necessary to release the timer's lock
715 * and try again. (This happens when the timer is in the middle of firing.)
717 int posix_cpu_timer_set(struct k_itimer *timer, int flags,
718 struct itimerspec *new, struct itimerspec *old)
720 struct task_struct *p = timer->it.cpu.task;
721 union cpu_time_count old_expires, new_expires, val;
722 int ret;
724 if (unlikely(p == NULL)) {
726 * Timer refers to a dead task's clock.
728 return -ESRCH;
731 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
733 read_lock(&tasklist_lock);
735 * We need the tasklist_lock to protect against reaping that
736 * clears p->signal. If p has just been reaped, we can no
737 * longer get any information about it at all.
739 if (unlikely(p->signal == NULL)) {
740 read_unlock(&tasklist_lock);
741 put_task_struct(p);
742 timer->it.cpu.task = NULL;
743 return -ESRCH;
747 * Disarm any old timer after extracting its expiry time.
749 BUG_ON(!irqs_disabled());
751 ret = 0;
752 spin_lock(&p->sighand->siglock);
753 old_expires = timer->it.cpu.expires;
754 if (unlikely(timer->it.cpu.firing)) {
755 timer->it.cpu.firing = -1;
756 ret = TIMER_RETRY;
757 } else
758 list_del_init(&timer->it.cpu.entry);
759 spin_unlock(&p->sighand->siglock);
762 * We need to sample the current value to convert the new
763 * value from to relative and absolute, and to convert the
764 * old value from absolute to relative. To set a process
765 * timer, we need a sample to balance the thread expiry
766 * times (in arm_timer). With an absolute time, we must
767 * check if it's already passed. In short, we need a sample.
769 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
770 cpu_clock_sample(timer->it_clock, p, &val);
771 } else {
772 cpu_timer_sample_group(timer->it_clock, p, &val);
775 if (old) {
776 if (old_expires.sched == 0) {
777 old->it_value.tv_sec = 0;
778 old->it_value.tv_nsec = 0;
779 } else {
781 * Update the timer in case it has
782 * overrun already. If it has,
783 * we'll report it as having overrun
784 * and with the next reloaded timer
785 * already ticking, though we are
786 * swallowing that pending
787 * notification here to install the
788 * new setting.
790 bump_cpu_timer(timer, val);
791 if (cpu_time_before(timer->it_clock, val,
792 timer->it.cpu.expires)) {
793 old_expires = cpu_time_sub(
794 timer->it_clock,
795 timer->it.cpu.expires, val);
796 sample_to_timespec(timer->it_clock,
797 old_expires,
798 &old->it_value);
799 } else {
800 old->it_value.tv_nsec = 1;
801 old->it_value.tv_sec = 0;
806 if (unlikely(ret)) {
808 * We are colliding with the timer actually firing.
809 * Punt after filling in the timer's old value, and
810 * disable this firing since we are already reporting
811 * it as an overrun (thanks to bump_cpu_timer above).
813 read_unlock(&tasklist_lock);
814 goto out;
817 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
818 cpu_time_add(timer->it_clock, &new_expires, val);
822 * Install the new expiry time (or zero).
823 * For a timer with no notification action, we don't actually
824 * arm the timer (we'll just fake it for timer_gettime).
826 timer->it.cpu.expires = new_expires;
827 if (new_expires.sched != 0 &&
828 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
829 cpu_time_before(timer->it_clock, val, new_expires)) {
830 arm_timer(timer, val);
833 read_unlock(&tasklist_lock);
836 * Install the new reload setting, and
837 * set up the signal and overrun bookkeeping.
839 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
840 &new->it_interval);
843 * This acts as a modification timestamp for the timer,
844 * so any automatic reload attempt will punt on seeing
845 * that we have reset the timer manually.
847 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
848 ~REQUEUE_PENDING;
849 timer->it_overrun_last = 0;
850 timer->it_overrun = -1;
852 if (new_expires.sched != 0 &&
853 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
854 !cpu_time_before(timer->it_clock, val, new_expires)) {
856 * The designated time already passed, so we notify
857 * immediately, even if the thread never runs to
858 * accumulate more time on this clock.
860 cpu_timer_fire(timer);
863 ret = 0;
864 out:
865 if (old) {
866 sample_to_timespec(timer->it_clock,
867 timer->it.cpu.incr, &old->it_interval);
869 return ret;
872 void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
874 union cpu_time_count now;
875 struct task_struct *p = timer->it.cpu.task;
876 int clear_dead;
879 * Easy part: convert the reload time.
881 sample_to_timespec(timer->it_clock,
882 timer->it.cpu.incr, &itp->it_interval);
884 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
885 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
886 return;
889 if (unlikely(p == NULL)) {
891 * This task already died and the timer will never fire.
892 * In this case, expires is actually the dead value.
894 dead:
895 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
896 &itp->it_value);
897 return;
901 * Sample the clock to take the difference with the expiry time.
903 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
904 cpu_clock_sample(timer->it_clock, p, &now);
905 clear_dead = p->exit_state;
906 } else {
907 read_lock(&tasklist_lock);
908 if (unlikely(p->signal == NULL)) {
910 * The process has been reaped.
911 * We can't even collect a sample any more.
912 * Call the timer disarmed, nothing else to do.
914 put_task_struct(p);
915 timer->it.cpu.task = NULL;
916 timer->it.cpu.expires.sched = 0;
917 read_unlock(&tasklist_lock);
918 goto dead;
919 } else {
920 cpu_timer_sample_group(timer->it_clock, p, &now);
921 clear_dead = (unlikely(p->exit_state) &&
922 thread_group_empty(p));
924 read_unlock(&tasklist_lock);
927 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
928 if (timer->it.cpu.incr.sched == 0 &&
929 cpu_time_before(timer->it_clock,
930 timer->it.cpu.expires, now)) {
932 * Do-nothing timer expired and has no reload,
933 * so it's as if it was never set.
935 timer->it.cpu.expires.sched = 0;
936 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
937 return;
940 * Account for any expirations and reloads that should
941 * have happened.
943 bump_cpu_timer(timer, now);
946 if (unlikely(clear_dead)) {
948 * We've noticed that the thread is dead, but
949 * not yet reaped. Take this opportunity to
950 * drop our task ref.
952 clear_dead_task(timer, now);
953 goto dead;
956 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
957 sample_to_timespec(timer->it_clock,
958 cpu_time_sub(timer->it_clock,
959 timer->it.cpu.expires, now),
960 &itp->it_value);
961 } else {
963 * The timer should have expired already, but the firing
964 * hasn't taken place yet. Say it's just about to expire.
966 itp->it_value.tv_nsec = 1;
967 itp->it_value.tv_sec = 0;
972 * Check for any per-thread CPU timers that have fired and move them off
973 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
974 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
976 static void check_thread_timers(struct task_struct *tsk,
977 struct list_head *firing)
979 int maxfire;
980 struct list_head *timers = tsk->cpu_timers;
981 struct signal_struct *const sig = tsk->signal;
983 maxfire = 20;
984 tsk->cputime_expires.prof_exp = cputime_zero;
985 while (!list_empty(timers)) {
986 struct cpu_timer_list *t = list_first_entry(timers,
987 struct cpu_timer_list,
988 entry);
989 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
990 tsk->cputime_expires.prof_exp = t->expires.cpu;
991 break;
993 t->firing = 1;
994 list_move_tail(&t->entry, firing);
997 ++timers;
998 maxfire = 20;
999 tsk->cputime_expires.virt_exp = cputime_zero;
1000 while (!list_empty(timers)) {
1001 struct cpu_timer_list *t = list_first_entry(timers,
1002 struct cpu_timer_list,
1003 entry);
1004 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
1005 tsk->cputime_expires.virt_exp = t->expires.cpu;
1006 break;
1008 t->firing = 1;
1009 list_move_tail(&t->entry, firing);
1012 ++timers;
1013 maxfire = 20;
1014 tsk->cputime_expires.sched_exp = 0;
1015 while (!list_empty(timers)) {
1016 struct cpu_timer_list *t = list_first_entry(timers,
1017 struct cpu_timer_list,
1018 entry);
1019 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
1020 tsk->cputime_expires.sched_exp = t->expires.sched;
1021 break;
1023 t->firing = 1;
1024 list_move_tail(&t->entry, firing);
1028 * Check for the special case thread timers.
1030 if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
1031 unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
1032 unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
1034 if (hard != RLIM_INFINITY &&
1035 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
1037 * At the hard limit, we just die.
1038 * No need to calculate anything else now.
1040 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1041 return;
1043 if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
1045 * At the soft limit, send a SIGXCPU every second.
1047 if (sig->rlim[RLIMIT_RTTIME].rlim_cur
1048 < sig->rlim[RLIMIT_RTTIME].rlim_max) {
1049 sig->rlim[RLIMIT_RTTIME].rlim_cur +=
1050 USEC_PER_SEC;
1052 printk(KERN_INFO
1053 "RT Watchdog Timeout: %s[%d]\n",
1054 tsk->comm, task_pid_nr(tsk));
1055 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1060 static void stop_process_timers(struct task_struct *tsk)
1062 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
1063 unsigned long flags;
1065 if (!cputimer->running)
1066 return;
1068 spin_lock_irqsave(&cputimer->lock, flags);
1069 cputimer->running = 0;
1070 spin_unlock_irqrestore(&cputimer->lock, flags);
1074 * Check for any per-thread CPU timers that have fired and move them
1075 * off the tsk->*_timers list onto the firing list. Per-thread timers
1076 * have already been taken off.
1078 static void check_process_timers(struct task_struct *tsk,
1079 struct list_head *firing)
1081 int maxfire;
1082 struct signal_struct *const sig = tsk->signal;
1083 cputime_t utime, ptime, virt_expires, prof_expires;
1084 unsigned long long sum_sched_runtime, sched_expires;
1085 struct list_head *timers = sig->cpu_timers;
1086 struct task_cputime cputime;
1089 * Don't sample the current process CPU clocks if there are no timers.
1091 if (list_empty(&timers[CPUCLOCK_PROF]) &&
1092 cputime_eq(sig->it_prof_expires, cputime_zero) &&
1093 sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
1094 list_empty(&timers[CPUCLOCK_VIRT]) &&
1095 cputime_eq(sig->it_virt_expires, cputime_zero) &&
1096 list_empty(&timers[CPUCLOCK_SCHED])) {
1097 stop_process_timers(tsk);
1098 return;
1102 * Collect the current process totals.
1104 thread_group_cputimer(tsk, &cputime);
1105 utime = cputime.utime;
1106 ptime = cputime_add(utime, cputime.stime);
1107 sum_sched_runtime = cputime.sum_exec_runtime;
1108 maxfire = 20;
1109 prof_expires = cputime_zero;
1110 while (!list_empty(timers)) {
1111 struct cpu_timer_list *tl = list_first_entry(timers,
1112 struct cpu_timer_list,
1113 entry);
1114 if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
1115 prof_expires = tl->expires.cpu;
1116 break;
1118 tl->firing = 1;
1119 list_move_tail(&tl->entry, firing);
1122 ++timers;
1123 maxfire = 20;
1124 virt_expires = cputime_zero;
1125 while (!list_empty(timers)) {
1126 struct cpu_timer_list *tl = list_first_entry(timers,
1127 struct cpu_timer_list,
1128 entry);
1129 if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
1130 virt_expires = tl->expires.cpu;
1131 break;
1133 tl->firing = 1;
1134 list_move_tail(&tl->entry, firing);
1137 ++timers;
1138 maxfire = 20;
1139 sched_expires = 0;
1140 while (!list_empty(timers)) {
1141 struct cpu_timer_list *tl = list_first_entry(timers,
1142 struct cpu_timer_list,
1143 entry);
1144 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1145 sched_expires = tl->expires.sched;
1146 break;
1148 tl->firing = 1;
1149 list_move_tail(&tl->entry, firing);
1153 * Check for the special case process timers.
1155 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1156 if (cputime_ge(ptime, sig->it_prof_expires)) {
1157 /* ITIMER_PROF fires and reloads. */
1158 sig->it_prof_expires = sig->it_prof_incr;
1159 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1160 sig->it_prof_expires = cputime_add(
1161 sig->it_prof_expires, ptime);
1163 __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
1165 if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
1166 (cputime_eq(prof_expires, cputime_zero) ||
1167 cputime_lt(sig->it_prof_expires, prof_expires))) {
1168 prof_expires = sig->it_prof_expires;
1171 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1172 if (cputime_ge(utime, sig->it_virt_expires)) {
1173 /* ITIMER_VIRTUAL fires and reloads. */
1174 sig->it_virt_expires = sig->it_virt_incr;
1175 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1176 sig->it_virt_expires = cputime_add(
1177 sig->it_virt_expires, utime);
1179 __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
1181 if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
1182 (cputime_eq(virt_expires, cputime_zero) ||
1183 cputime_lt(sig->it_virt_expires, virt_expires))) {
1184 virt_expires = sig->it_virt_expires;
1187 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
1188 unsigned long psecs = cputime_to_secs(ptime);
1189 cputime_t x;
1190 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
1192 * At the hard limit, we just die.
1193 * No need to calculate anything else now.
1195 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1196 return;
1198 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
1200 * At the soft limit, send a SIGXCPU every second.
1202 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1203 if (sig->rlim[RLIMIT_CPU].rlim_cur
1204 < sig->rlim[RLIMIT_CPU].rlim_max) {
1205 sig->rlim[RLIMIT_CPU].rlim_cur++;
1208 x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
1209 if (cputime_eq(prof_expires, cputime_zero) ||
1210 cputime_lt(x, prof_expires)) {
1211 prof_expires = x;
1215 if (!cputime_eq(prof_expires, cputime_zero) &&
1216 (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
1217 cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
1218 sig->cputime_expires.prof_exp = prof_expires;
1219 if (!cputime_eq(virt_expires, cputime_zero) &&
1220 (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
1221 cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
1222 sig->cputime_expires.virt_exp = virt_expires;
1223 if (sched_expires != 0 &&
1224 (sig->cputime_expires.sched_exp == 0 ||
1225 sig->cputime_expires.sched_exp > sched_expires))
1226 sig->cputime_expires.sched_exp = sched_expires;
1230 * This is called from the signal code (via do_schedule_next_timer)
1231 * when the last timer signal was delivered and we have to reload the timer.
1233 void posix_cpu_timer_schedule(struct k_itimer *timer)
1235 struct task_struct *p = timer->it.cpu.task;
1236 union cpu_time_count now;
1238 if (unlikely(p == NULL))
1240 * The task was cleaned up already, no future firings.
1242 goto out;
1245 * Fetch the current sample and update the timer's expiry time.
1247 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1248 cpu_clock_sample(timer->it_clock, p, &now);
1249 bump_cpu_timer(timer, now);
1250 if (unlikely(p->exit_state)) {
1251 clear_dead_task(timer, now);
1252 goto out;
1254 read_lock(&tasklist_lock); /* arm_timer needs it. */
1255 } else {
1256 read_lock(&tasklist_lock);
1257 if (unlikely(p->signal == NULL)) {
1259 * The process has been reaped.
1260 * We can't even collect a sample any more.
1262 put_task_struct(p);
1263 timer->it.cpu.task = p = NULL;
1264 timer->it.cpu.expires.sched = 0;
1265 goto out_unlock;
1266 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1268 * We've noticed that the thread is dead, but
1269 * not yet reaped. Take this opportunity to
1270 * drop our task ref.
1272 clear_dead_task(timer, now);
1273 goto out_unlock;
1275 cpu_timer_sample_group(timer->it_clock, p, &now);
1276 bump_cpu_timer(timer, now);
1277 /* Leave the tasklist_lock locked for the call below. */
1281 * Now re-arm for the new expiry time.
1283 arm_timer(timer, now);
1285 out_unlock:
1286 read_unlock(&tasklist_lock);
1288 out:
1289 timer->it_overrun_last = timer->it_overrun;
1290 timer->it_overrun = -1;
1291 ++timer->it_requeue_pending;
1295 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1297 * @cputime: The struct to compare.
1299 * Checks @cputime to see if all fields are zero. Returns true if all fields
1300 * are zero, false if any field is nonzero.
1302 static inline int task_cputime_zero(const struct task_cputime *cputime)
1304 if (cputime_eq(cputime->utime, cputime_zero) &&
1305 cputime_eq(cputime->stime, cputime_zero) &&
1306 cputime->sum_exec_runtime == 0)
1307 return 1;
1308 return 0;
1312 * task_cputime_expired - Compare two task_cputime entities.
1314 * @sample: The task_cputime structure to be checked for expiration.
1315 * @expires: Expiration times, against which @sample will be checked.
1317 * Checks @sample against @expires to see if any field of @sample has expired.
1318 * Returns true if any field of the former is greater than the corresponding
1319 * field of the latter if the latter field is set. Otherwise returns false.
1321 static inline int task_cputime_expired(const struct task_cputime *sample,
1322 const struct task_cputime *expires)
1324 if (!cputime_eq(expires->utime, cputime_zero) &&
1325 cputime_ge(sample->utime, expires->utime))
1326 return 1;
1327 if (!cputime_eq(expires->stime, cputime_zero) &&
1328 cputime_ge(cputime_add(sample->utime, sample->stime),
1329 expires->stime))
1330 return 1;
1331 if (expires->sum_exec_runtime != 0 &&
1332 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1333 return 1;
1334 return 0;
1338 * fastpath_timer_check - POSIX CPU timers fast path.
1340 * @tsk: The task (thread) being checked.
1342 * Check the task and thread group timers. If both are zero (there are no
1343 * timers set) return false. Otherwise snapshot the task and thread group
1344 * timers and compare them with the corresponding expiration times. Return
1345 * true if a timer has expired, else return false.
1347 static inline int fastpath_timer_check(struct task_struct *tsk)
1349 struct signal_struct *sig;
1351 /* tsk == current, ensure it is safe to use ->signal/sighand */
1352 if (unlikely(tsk->exit_state))
1353 return 0;
1355 if (!task_cputime_zero(&tsk->cputime_expires)) {
1356 struct task_cputime task_sample = {
1357 .utime = tsk->utime,
1358 .stime = tsk->stime,
1359 .sum_exec_runtime = tsk->se.sum_exec_runtime
1362 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1363 return 1;
1366 sig = tsk->signal;
1367 if (!task_cputime_zero(&sig->cputime_expires)) {
1368 struct task_cputime group_sample;
1370 thread_group_cputimer(tsk, &group_sample);
1371 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1372 return 1;
1375 return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
1379 * This is called from the timer interrupt handler. The irq handler has
1380 * already updated our counts. We need to check if any timers fire now.
1381 * Interrupts are disabled.
1383 void run_posix_cpu_timers(struct task_struct *tsk)
1385 LIST_HEAD(firing);
1386 struct k_itimer *timer, *next;
1388 BUG_ON(!irqs_disabled());
1391 * The fast path checks that there are no expired thread or thread
1392 * group timers. If that's so, just return.
1394 if (!fastpath_timer_check(tsk))
1395 return;
1397 spin_lock(&tsk->sighand->siglock);
1399 * Here we take off tsk->signal->cpu_timers[N] and
1400 * tsk->cpu_timers[N] all the timers that are firing, and
1401 * put them on the firing list.
1403 check_thread_timers(tsk, &firing);
1404 check_process_timers(tsk, &firing);
1407 * We must release these locks before taking any timer's lock.
1408 * There is a potential race with timer deletion here, as the
1409 * siglock now protects our private firing list. We have set
1410 * the firing flag in each timer, so that a deletion attempt
1411 * that gets the timer lock before we do will give it up and
1412 * spin until we've taken care of that timer below.
1414 spin_unlock(&tsk->sighand->siglock);
1417 * Now that all the timers on our list have the firing flag,
1418 * noone will touch their list entries but us. We'll take
1419 * each timer's lock before clearing its firing flag, so no
1420 * timer call will interfere.
1422 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1423 int cpu_firing;
1425 spin_lock(&timer->it_lock);
1426 list_del_init(&timer->it.cpu.entry);
1427 cpu_firing = timer->it.cpu.firing;
1428 timer->it.cpu.firing = 0;
1430 * The firing flag is -1 if we collided with a reset
1431 * of the timer, which already reported this
1432 * almost-firing as an overrun. So don't generate an event.
1434 if (likely(cpu_firing >= 0))
1435 cpu_timer_fire(timer);
1436 spin_unlock(&timer->it_lock);
1441 * Set one of the process-wide special case CPU timers.
1442 * The tsk->sighand->siglock must be held by the caller.
1443 * The *newval argument is relative and we update it to be absolute, *oldval
1444 * is absolute and we update it to be relative.
1446 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1447 cputime_t *newval, cputime_t *oldval)
1449 union cpu_time_count now;
1450 struct list_head *head;
1452 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1453 cpu_timer_sample_group(clock_idx, tsk, &now);
1455 if (oldval) {
1456 if (!cputime_eq(*oldval, cputime_zero)) {
1457 if (cputime_le(*oldval, now.cpu)) {
1458 /* Just about to fire. */
1459 *oldval = jiffies_to_cputime(1);
1460 } else {
1461 *oldval = cputime_sub(*oldval, now.cpu);
1465 if (cputime_eq(*newval, cputime_zero))
1466 return;
1467 *newval = cputime_add(*newval, now.cpu);
1470 * If the RLIMIT_CPU timer will expire before the
1471 * ITIMER_PROF timer, we have nothing else to do.
1473 if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
1474 < cputime_to_secs(*newval))
1475 return;
1479 * Check whether there are any process timers already set to fire
1480 * before this one. If so, we don't have anything more to do.
1482 head = &tsk->signal->cpu_timers[clock_idx];
1483 if (list_empty(head) ||
1484 cputime_ge(list_first_entry(head,
1485 struct cpu_timer_list, entry)->expires.cpu,
1486 *newval)) {
1487 switch (clock_idx) {
1488 case CPUCLOCK_PROF:
1489 tsk->signal->cputime_expires.prof_exp = *newval;
1490 break;
1491 case CPUCLOCK_VIRT:
1492 tsk->signal->cputime_expires.virt_exp = *newval;
1493 break;
1498 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1499 struct timespec *rqtp, struct itimerspec *it)
1501 struct k_itimer timer;
1502 int error;
1505 * Set up a temporary timer and then wait for it to go off.
1507 memset(&timer, 0, sizeof timer);
1508 spin_lock_init(&timer.it_lock);
1509 timer.it_clock = which_clock;
1510 timer.it_overrun = -1;
1511 error = posix_cpu_timer_create(&timer);
1512 timer.it_process = current;
1513 if (!error) {
1514 static struct itimerspec zero_it;
1516 memset(it, 0, sizeof *it);
1517 it->it_value = *rqtp;
1519 spin_lock_irq(&timer.it_lock);
1520 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1521 if (error) {
1522 spin_unlock_irq(&timer.it_lock);
1523 return error;
1526 while (!signal_pending(current)) {
1527 if (timer.it.cpu.expires.sched == 0) {
1529 * Our timer fired and was reset.
1531 spin_unlock_irq(&timer.it_lock);
1532 return 0;
1536 * Block until cpu_timer_fire (or a signal) wakes us.
1538 __set_current_state(TASK_INTERRUPTIBLE);
1539 spin_unlock_irq(&timer.it_lock);
1540 schedule();
1541 spin_lock_irq(&timer.it_lock);
1545 * We were interrupted by a signal.
1547 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1548 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1549 spin_unlock_irq(&timer.it_lock);
1551 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1553 * It actually did fire already.
1555 return 0;
1558 error = -ERESTART_RESTARTBLOCK;
1561 return error;
1564 int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1565 struct timespec *rqtp, struct timespec __user *rmtp)
1567 struct restart_block *restart_block =
1568 &current_thread_info()->restart_block;
1569 struct itimerspec it;
1570 int error;
1573 * Diagnose required errors first.
1575 if (CPUCLOCK_PERTHREAD(which_clock) &&
1576 (CPUCLOCK_PID(which_clock) == 0 ||
1577 CPUCLOCK_PID(which_clock) == current->pid))
1578 return -EINVAL;
1580 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1582 if (error == -ERESTART_RESTARTBLOCK) {
1584 if (flags & TIMER_ABSTIME)
1585 return -ERESTARTNOHAND;
1587 * Report back to the user the time still remaining.
1589 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1590 return -EFAULT;
1592 restart_block->fn = posix_cpu_nsleep_restart;
1593 restart_block->arg0 = which_clock;
1594 restart_block->arg1 = (unsigned long) rmtp;
1595 restart_block->arg2 = rqtp->tv_sec;
1596 restart_block->arg3 = rqtp->tv_nsec;
1598 return error;
1601 long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1603 clockid_t which_clock = restart_block->arg0;
1604 struct timespec __user *rmtp;
1605 struct timespec t;
1606 struct itimerspec it;
1607 int error;
1609 rmtp = (struct timespec __user *) restart_block->arg1;
1610 t.tv_sec = restart_block->arg2;
1611 t.tv_nsec = restart_block->arg3;
1613 restart_block->fn = do_no_restart_syscall;
1614 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1616 if (error == -ERESTART_RESTARTBLOCK) {
1618 * Report back to the user the time still remaining.
1620 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1621 return -EFAULT;
1623 restart_block->fn = posix_cpu_nsleep_restart;
1624 restart_block->arg0 = which_clock;
1625 restart_block->arg1 = (unsigned long) rmtp;
1626 restart_block->arg2 = t.tv_sec;
1627 restart_block->arg3 = t.tv_nsec;
1629 return error;
1634 #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1635 #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1637 static int process_cpu_clock_getres(const clockid_t which_clock,
1638 struct timespec *tp)
1640 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1642 static int process_cpu_clock_get(const clockid_t which_clock,
1643 struct timespec *tp)
1645 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1647 static int process_cpu_timer_create(struct k_itimer *timer)
1649 timer->it_clock = PROCESS_CLOCK;
1650 return posix_cpu_timer_create(timer);
1652 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1653 struct timespec *rqtp,
1654 struct timespec __user *rmtp)
1656 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1658 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1660 return -EINVAL;
1662 static int thread_cpu_clock_getres(const clockid_t which_clock,
1663 struct timespec *tp)
1665 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1667 static int thread_cpu_clock_get(const clockid_t which_clock,
1668 struct timespec *tp)
1670 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1672 static int thread_cpu_timer_create(struct k_itimer *timer)
1674 timer->it_clock = THREAD_CLOCK;
1675 return posix_cpu_timer_create(timer);
1677 static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
1678 struct timespec *rqtp, struct timespec __user *rmtp)
1680 return -EINVAL;
1682 static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
1684 return -EINVAL;
1687 static __init int init_posix_cpu_timers(void)
1689 struct k_clock process = {
1690 .clock_getres = process_cpu_clock_getres,
1691 .clock_get = process_cpu_clock_get,
1692 .clock_set = do_posix_clock_nosettime,
1693 .timer_create = process_cpu_timer_create,
1694 .nsleep = process_cpu_nsleep,
1695 .nsleep_restart = process_cpu_nsleep_restart,
1697 struct k_clock thread = {
1698 .clock_getres = thread_cpu_clock_getres,
1699 .clock_get = thread_cpu_clock_get,
1700 .clock_set = do_posix_clock_nosettime,
1701 .timer_create = thread_cpu_timer_create,
1702 .nsleep = thread_cpu_nsleep,
1703 .nsleep_restart = thread_cpu_nsleep_restart,
1706 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1707 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1709 return 0;
1711 __initcall(init_posix_cpu_timers);