thinkpad-acpi: convert to seq_file
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / posix-cpu-timers.c
blobe33a21cb9407987a0aa9b46c32baba590302862b
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 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);
546 * Insert the timer on the appropriate list before any timers that
547 * expire later. This must be called with the tasklist_lock held
548 * for reading, and interrupts disabled.
550 static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
552 struct task_struct *p = timer->it.cpu.task;
553 struct list_head *head, *listpos;
554 struct cpu_timer_list *const nt = &timer->it.cpu;
555 struct cpu_timer_list *next;
556 unsigned long i;
558 head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
559 p->cpu_timers : p->signal->cpu_timers);
560 head += CPUCLOCK_WHICH(timer->it_clock);
562 BUG_ON(!irqs_disabled());
563 spin_lock(&p->sighand->siglock);
565 listpos = head;
566 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
567 list_for_each_entry(next, head, entry) {
568 if (next->expires.sched > nt->expires.sched)
569 break;
570 listpos = &next->entry;
572 } else {
573 list_for_each_entry(next, head, entry) {
574 if (cputime_gt(next->expires.cpu, nt->expires.cpu))
575 break;
576 listpos = &next->entry;
579 list_add(&nt->entry, listpos);
581 if (listpos == head) {
583 * We are the new earliest-expiring timer.
584 * If we are a thread timer, there can always
585 * be a process timer telling us to stop earlier.
588 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
589 switch (CPUCLOCK_WHICH(timer->it_clock)) {
590 default:
591 BUG();
592 case CPUCLOCK_PROF:
593 if (cputime_eq(p->cputime_expires.prof_exp,
594 cputime_zero) ||
595 cputime_gt(p->cputime_expires.prof_exp,
596 nt->expires.cpu))
597 p->cputime_expires.prof_exp =
598 nt->expires.cpu;
599 break;
600 case CPUCLOCK_VIRT:
601 if (cputime_eq(p->cputime_expires.virt_exp,
602 cputime_zero) ||
603 cputime_gt(p->cputime_expires.virt_exp,
604 nt->expires.cpu))
605 p->cputime_expires.virt_exp =
606 nt->expires.cpu;
607 break;
608 case CPUCLOCK_SCHED:
609 if (p->cputime_expires.sched_exp == 0 ||
610 p->cputime_expires.sched_exp >
611 nt->expires.sched)
612 p->cputime_expires.sched_exp =
613 nt->expires.sched;
614 break;
616 } else {
618 * For a process timer, set the cached expiration time.
620 switch (CPUCLOCK_WHICH(timer->it_clock)) {
621 default:
622 BUG();
623 case CPUCLOCK_VIRT:
624 if (!cputime_eq(p->signal->it_virt_expires,
625 cputime_zero) &&
626 cputime_lt(p->signal->it_virt_expires,
627 timer->it.cpu.expires.cpu))
628 break;
629 p->signal->cputime_expires.virt_exp =
630 timer->it.cpu.expires.cpu;
631 break;
632 case CPUCLOCK_PROF:
633 if (!cputime_eq(p->signal->it_prof_expires,
634 cputime_zero) &&
635 cputime_lt(p->signal->it_prof_expires,
636 timer->it.cpu.expires.cpu))
637 break;
638 i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
639 if (i != RLIM_INFINITY &&
640 i <= cputime_to_secs(timer->it.cpu.expires.cpu))
641 break;
642 p->signal->cputime_expires.prof_exp =
643 timer->it.cpu.expires.cpu;
644 break;
645 case CPUCLOCK_SCHED:
646 p->signal->cputime_expires.sched_exp =
647 timer->it.cpu.expires.sched;
648 break;
653 spin_unlock(&p->sighand->siglock);
657 * The timer is locked, fire it and arrange for its reload.
659 static void cpu_timer_fire(struct k_itimer *timer)
661 if (unlikely(timer->sigq == NULL)) {
663 * This a special case for clock_nanosleep,
664 * not a normal timer from sys_timer_create.
666 wake_up_process(timer->it_process);
667 timer->it.cpu.expires.sched = 0;
668 } else if (timer->it.cpu.incr.sched == 0) {
670 * One-shot timer. Clear it as soon as it's fired.
672 posix_timer_event(timer, 0);
673 timer->it.cpu.expires.sched = 0;
674 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
676 * The signal did not get queued because the signal
677 * was ignored, so we won't get any callback to
678 * reload the timer. But we need to keep it
679 * ticking in case the signal is deliverable next time.
681 posix_cpu_timer_schedule(timer);
686 * Sample a process (thread group) timer for the given group_leader task.
687 * Must be called with tasklist_lock held for reading.
689 static int cpu_timer_sample_group(const clockid_t which_clock,
690 struct task_struct *p,
691 union cpu_time_count *cpu)
693 struct task_cputime cputime;
695 thread_group_cputimer(p, &cputime);
696 switch (CPUCLOCK_WHICH(which_clock)) {
697 default:
698 return -EINVAL;
699 case CPUCLOCK_PROF:
700 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
701 break;
702 case CPUCLOCK_VIRT:
703 cpu->cpu = cputime.utime;
704 break;
705 case CPUCLOCK_SCHED:
706 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
707 break;
709 return 0;
713 * Guts of sys_timer_settime for CPU timers.
714 * This is called with the timer locked and interrupts disabled.
715 * If we return TIMER_RETRY, it's necessary to release the timer's lock
716 * and try again. (This happens when the timer is in the middle of firing.)
718 int posix_cpu_timer_set(struct k_itimer *timer, int flags,
719 struct itimerspec *new, struct itimerspec *old)
721 struct task_struct *p = timer->it.cpu.task;
722 union cpu_time_count old_expires, new_expires, val;
723 int ret;
725 if (unlikely(p == NULL)) {
727 * Timer refers to a dead task's clock.
729 return -ESRCH;
732 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
734 read_lock(&tasklist_lock);
736 * We need the tasklist_lock to protect against reaping that
737 * clears p->signal. If p has just been reaped, we can no
738 * longer get any information about it at all.
740 if (unlikely(p->signal == NULL)) {
741 read_unlock(&tasklist_lock);
742 put_task_struct(p);
743 timer->it.cpu.task = NULL;
744 return -ESRCH;
748 * Disarm any old timer after extracting its expiry time.
750 BUG_ON(!irqs_disabled());
752 ret = 0;
753 spin_lock(&p->sighand->siglock);
754 old_expires = timer->it.cpu.expires;
755 if (unlikely(timer->it.cpu.firing)) {
756 timer->it.cpu.firing = -1;
757 ret = TIMER_RETRY;
758 } else
759 list_del_init(&timer->it.cpu.entry);
760 spin_unlock(&p->sighand->siglock);
763 * We need to sample the current value to convert the new
764 * value from to relative and absolute, and to convert the
765 * old value from absolute to relative. To set a process
766 * timer, we need a sample to balance the thread expiry
767 * times (in arm_timer). With an absolute time, we must
768 * check if it's already passed. In short, we need a sample.
770 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
771 cpu_clock_sample(timer->it_clock, p, &val);
772 } else {
773 cpu_timer_sample_group(timer->it_clock, p, &val);
776 if (old) {
777 if (old_expires.sched == 0) {
778 old->it_value.tv_sec = 0;
779 old->it_value.tv_nsec = 0;
780 } else {
782 * Update the timer in case it has
783 * overrun already. If it has,
784 * we'll report it as having overrun
785 * and with the next reloaded timer
786 * already ticking, though we are
787 * swallowing that pending
788 * notification here to install the
789 * new setting.
791 bump_cpu_timer(timer, val);
792 if (cpu_time_before(timer->it_clock, val,
793 timer->it.cpu.expires)) {
794 old_expires = cpu_time_sub(
795 timer->it_clock,
796 timer->it.cpu.expires, val);
797 sample_to_timespec(timer->it_clock,
798 old_expires,
799 &old->it_value);
800 } else {
801 old->it_value.tv_nsec = 1;
802 old->it_value.tv_sec = 0;
807 if (unlikely(ret)) {
809 * We are colliding with the timer actually firing.
810 * Punt after filling in the timer's old value, and
811 * disable this firing since we are already reporting
812 * it as an overrun (thanks to bump_cpu_timer above).
814 read_unlock(&tasklist_lock);
815 goto out;
818 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
819 cpu_time_add(timer->it_clock, &new_expires, val);
823 * Install the new expiry time (or zero).
824 * For a timer with no notification action, we don't actually
825 * arm the timer (we'll just fake it for timer_gettime).
827 timer->it.cpu.expires = new_expires;
828 if (new_expires.sched != 0 &&
829 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
830 cpu_time_before(timer->it_clock, val, new_expires)) {
831 arm_timer(timer, val);
834 read_unlock(&tasklist_lock);
837 * Install the new reload setting, and
838 * set up the signal and overrun bookkeeping.
840 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
841 &new->it_interval);
844 * This acts as a modification timestamp for the timer,
845 * so any automatic reload attempt will punt on seeing
846 * that we have reset the timer manually.
848 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
849 ~REQUEUE_PENDING;
850 timer->it_overrun_last = 0;
851 timer->it_overrun = -1;
853 if (new_expires.sched != 0 &&
854 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
855 !cpu_time_before(timer->it_clock, val, new_expires)) {
857 * The designated time already passed, so we notify
858 * immediately, even if the thread never runs to
859 * accumulate more time on this clock.
861 cpu_timer_fire(timer);
864 ret = 0;
865 out:
866 if (old) {
867 sample_to_timespec(timer->it_clock,
868 timer->it.cpu.incr, &old->it_interval);
870 return ret;
873 void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
875 union cpu_time_count now;
876 struct task_struct *p = timer->it.cpu.task;
877 int clear_dead;
880 * Easy part: convert the reload time.
882 sample_to_timespec(timer->it_clock,
883 timer->it.cpu.incr, &itp->it_interval);
885 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
886 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
887 return;
890 if (unlikely(p == NULL)) {
892 * This task already died and the timer will never fire.
893 * In this case, expires is actually the dead value.
895 dead:
896 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
897 &itp->it_value);
898 return;
902 * Sample the clock to take the difference with the expiry time.
904 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
905 cpu_clock_sample(timer->it_clock, p, &now);
906 clear_dead = p->exit_state;
907 } else {
908 read_lock(&tasklist_lock);
909 if (unlikely(p->signal == NULL)) {
911 * The process has been reaped.
912 * We can't even collect a sample any more.
913 * Call the timer disarmed, nothing else to do.
915 put_task_struct(p);
916 timer->it.cpu.task = NULL;
917 timer->it.cpu.expires.sched = 0;
918 read_unlock(&tasklist_lock);
919 goto dead;
920 } else {
921 cpu_timer_sample_group(timer->it_clock, p, &now);
922 clear_dead = (unlikely(p->exit_state) &&
923 thread_group_empty(p));
925 read_unlock(&tasklist_lock);
928 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
929 if (timer->it.cpu.incr.sched == 0 &&
930 cpu_time_before(timer->it_clock,
931 timer->it.cpu.expires, now)) {
933 * Do-nothing timer expired and has no reload,
934 * so it's as if it was never set.
936 timer->it.cpu.expires.sched = 0;
937 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
938 return;
941 * Account for any expirations and reloads that should
942 * have happened.
944 bump_cpu_timer(timer, now);
947 if (unlikely(clear_dead)) {
949 * We've noticed that the thread is dead, but
950 * not yet reaped. Take this opportunity to
951 * drop our task ref.
953 clear_dead_task(timer, now);
954 goto dead;
957 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
958 sample_to_timespec(timer->it_clock,
959 cpu_time_sub(timer->it_clock,
960 timer->it.cpu.expires, now),
961 &itp->it_value);
962 } else {
964 * The timer should have expired already, but the firing
965 * hasn't taken place yet. Say it's just about to expire.
967 itp->it_value.tv_nsec = 1;
968 itp->it_value.tv_sec = 0;
973 * Check for any per-thread CPU timers that have fired and move them off
974 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
975 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
977 static void check_thread_timers(struct task_struct *tsk,
978 struct list_head *firing)
980 int maxfire;
981 struct list_head *timers = tsk->cpu_timers;
982 struct signal_struct *const sig = tsk->signal;
984 maxfire = 20;
985 tsk->cputime_expires.prof_exp = cputime_zero;
986 while (!list_empty(timers)) {
987 struct cpu_timer_list *t = list_first_entry(timers,
988 struct cpu_timer_list,
989 entry);
990 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
991 tsk->cputime_expires.prof_exp = t->expires.cpu;
992 break;
994 t->firing = 1;
995 list_move_tail(&t->entry, firing);
998 ++timers;
999 maxfire = 20;
1000 tsk->cputime_expires.virt_exp = cputime_zero;
1001 while (!list_empty(timers)) {
1002 struct cpu_timer_list *t = list_first_entry(timers,
1003 struct cpu_timer_list,
1004 entry);
1005 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
1006 tsk->cputime_expires.virt_exp = t->expires.cpu;
1007 break;
1009 t->firing = 1;
1010 list_move_tail(&t->entry, firing);
1013 ++timers;
1014 maxfire = 20;
1015 tsk->cputime_expires.sched_exp = 0;
1016 while (!list_empty(timers)) {
1017 struct cpu_timer_list *t = list_first_entry(timers,
1018 struct cpu_timer_list,
1019 entry);
1020 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
1021 tsk->cputime_expires.sched_exp = t->expires.sched;
1022 break;
1024 t->firing = 1;
1025 list_move_tail(&t->entry, firing);
1029 * Check for the special case thread timers.
1031 if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
1032 unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
1033 unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
1035 if (hard != RLIM_INFINITY &&
1036 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
1038 * At the hard limit, we just die.
1039 * No need to calculate anything else now.
1041 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1042 return;
1044 if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
1046 * At the soft limit, send a SIGXCPU every second.
1048 if (sig->rlim[RLIMIT_RTTIME].rlim_cur
1049 < sig->rlim[RLIMIT_RTTIME].rlim_max) {
1050 sig->rlim[RLIMIT_RTTIME].rlim_cur +=
1051 USEC_PER_SEC;
1053 printk(KERN_INFO
1054 "RT Watchdog Timeout: %s[%d]\n",
1055 tsk->comm, task_pid_nr(tsk));
1056 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1061 static void stop_process_timers(struct task_struct *tsk)
1063 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
1064 unsigned long flags;
1066 if (!cputimer->running)
1067 return;
1069 spin_lock_irqsave(&cputimer->lock, flags);
1070 cputimer->running = 0;
1071 spin_unlock_irqrestore(&cputimer->lock, flags);
1075 * Check for any per-thread CPU timers that have fired and move them
1076 * off the tsk->*_timers list onto the firing list. Per-thread timers
1077 * have already been taken off.
1079 static void check_process_timers(struct task_struct *tsk,
1080 struct list_head *firing)
1082 int maxfire;
1083 struct signal_struct *const sig = tsk->signal;
1084 cputime_t utime, ptime, virt_expires, prof_expires;
1085 unsigned long long sum_sched_runtime, sched_expires;
1086 struct list_head *timers = sig->cpu_timers;
1087 struct task_cputime cputime;
1090 * Don't sample the current process CPU clocks if there are no timers.
1092 if (list_empty(&timers[CPUCLOCK_PROF]) &&
1093 cputime_eq(sig->it_prof_expires, cputime_zero) &&
1094 sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
1095 list_empty(&timers[CPUCLOCK_VIRT]) &&
1096 cputime_eq(sig->it_virt_expires, cputime_zero) &&
1097 list_empty(&timers[CPUCLOCK_SCHED])) {
1098 stop_process_timers(tsk);
1099 return;
1103 * Collect the current process totals.
1105 thread_group_cputimer(tsk, &cputime);
1106 utime = cputime.utime;
1107 ptime = cputime_add(utime, cputime.stime);
1108 sum_sched_runtime = cputime.sum_exec_runtime;
1109 maxfire = 20;
1110 prof_expires = cputime_zero;
1111 while (!list_empty(timers)) {
1112 struct cpu_timer_list *tl = list_first_entry(timers,
1113 struct cpu_timer_list,
1114 entry);
1115 if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
1116 prof_expires = tl->expires.cpu;
1117 break;
1119 tl->firing = 1;
1120 list_move_tail(&tl->entry, firing);
1123 ++timers;
1124 maxfire = 20;
1125 virt_expires = cputime_zero;
1126 while (!list_empty(timers)) {
1127 struct cpu_timer_list *tl = list_first_entry(timers,
1128 struct cpu_timer_list,
1129 entry);
1130 if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
1131 virt_expires = tl->expires.cpu;
1132 break;
1134 tl->firing = 1;
1135 list_move_tail(&tl->entry, firing);
1138 ++timers;
1139 maxfire = 20;
1140 sched_expires = 0;
1141 while (!list_empty(timers)) {
1142 struct cpu_timer_list *tl = list_first_entry(timers,
1143 struct cpu_timer_list,
1144 entry);
1145 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1146 sched_expires = tl->expires.sched;
1147 break;
1149 tl->firing = 1;
1150 list_move_tail(&tl->entry, firing);
1154 * Check for the special case process timers.
1156 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1157 if (cputime_ge(ptime, sig->it_prof_expires)) {
1158 /* ITIMER_PROF fires and reloads. */
1159 sig->it_prof_expires = sig->it_prof_incr;
1160 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1161 sig->it_prof_expires = cputime_add(
1162 sig->it_prof_expires, ptime);
1164 __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
1166 if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
1167 (cputime_eq(prof_expires, cputime_zero) ||
1168 cputime_lt(sig->it_prof_expires, prof_expires))) {
1169 prof_expires = sig->it_prof_expires;
1172 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1173 if (cputime_ge(utime, sig->it_virt_expires)) {
1174 /* ITIMER_VIRTUAL fires and reloads. */
1175 sig->it_virt_expires = sig->it_virt_incr;
1176 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1177 sig->it_virt_expires = cputime_add(
1178 sig->it_virt_expires, utime);
1180 __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
1182 if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
1183 (cputime_eq(virt_expires, cputime_zero) ||
1184 cputime_lt(sig->it_virt_expires, virt_expires))) {
1185 virt_expires = sig->it_virt_expires;
1188 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
1189 unsigned long psecs = cputime_to_secs(ptime);
1190 cputime_t x;
1191 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
1193 * At the hard limit, we just die.
1194 * No need to calculate anything else now.
1196 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1197 return;
1199 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
1201 * At the soft limit, send a SIGXCPU every second.
1203 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1204 if (sig->rlim[RLIMIT_CPU].rlim_cur
1205 < sig->rlim[RLIMIT_CPU].rlim_max) {
1206 sig->rlim[RLIMIT_CPU].rlim_cur++;
1209 x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
1210 if (cputime_eq(prof_expires, cputime_zero) ||
1211 cputime_lt(x, prof_expires)) {
1212 prof_expires = x;
1216 if (!cputime_eq(prof_expires, cputime_zero) &&
1217 (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
1218 cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
1219 sig->cputime_expires.prof_exp = prof_expires;
1220 if (!cputime_eq(virt_expires, cputime_zero) &&
1221 (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
1222 cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
1223 sig->cputime_expires.virt_exp = virt_expires;
1224 if (sched_expires != 0 &&
1225 (sig->cputime_expires.sched_exp == 0 ||
1226 sig->cputime_expires.sched_exp > sched_expires))
1227 sig->cputime_expires.sched_exp = sched_expires;
1231 * This is called from the signal code (via do_schedule_next_timer)
1232 * when the last timer signal was delivered and we have to reload the timer.
1234 void posix_cpu_timer_schedule(struct k_itimer *timer)
1236 struct task_struct *p = timer->it.cpu.task;
1237 union cpu_time_count now;
1239 if (unlikely(p == NULL))
1241 * The task was cleaned up already, no future firings.
1243 goto out;
1246 * Fetch the current sample and update the timer's expiry time.
1248 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1249 cpu_clock_sample(timer->it_clock, p, &now);
1250 bump_cpu_timer(timer, now);
1251 if (unlikely(p->exit_state)) {
1252 clear_dead_task(timer, now);
1253 goto out;
1255 read_lock(&tasklist_lock); /* arm_timer needs it. */
1256 } else {
1257 read_lock(&tasklist_lock);
1258 if (unlikely(p->signal == NULL)) {
1260 * The process has been reaped.
1261 * We can't even collect a sample any more.
1263 put_task_struct(p);
1264 timer->it.cpu.task = p = NULL;
1265 timer->it.cpu.expires.sched = 0;
1266 goto out_unlock;
1267 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1269 * We've noticed that the thread is dead, but
1270 * not yet reaped. Take this opportunity to
1271 * drop our task ref.
1273 clear_dead_task(timer, now);
1274 goto out_unlock;
1276 cpu_timer_sample_group(timer->it_clock, p, &now);
1277 bump_cpu_timer(timer, now);
1278 /* Leave the tasklist_lock locked for the call below. */
1282 * Now re-arm for the new expiry time.
1284 arm_timer(timer, now);
1286 out_unlock:
1287 read_unlock(&tasklist_lock);
1289 out:
1290 timer->it_overrun_last = timer->it_overrun;
1291 timer->it_overrun = -1;
1292 ++timer->it_requeue_pending;
1296 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1298 * @cputime: The struct to compare.
1300 * Checks @cputime to see if all fields are zero. Returns true if all fields
1301 * are zero, false if any field is nonzero.
1303 static inline int task_cputime_zero(const struct task_cputime *cputime)
1305 if (cputime_eq(cputime->utime, cputime_zero) &&
1306 cputime_eq(cputime->stime, cputime_zero) &&
1307 cputime->sum_exec_runtime == 0)
1308 return 1;
1309 return 0;
1313 * task_cputime_expired - Compare two task_cputime entities.
1315 * @sample: The task_cputime structure to be checked for expiration.
1316 * @expires: Expiration times, against which @sample will be checked.
1318 * Checks @sample against @expires to see if any field of @sample has expired.
1319 * Returns true if any field of the former is greater than the corresponding
1320 * field of the latter if the latter field is set. Otherwise returns false.
1322 static inline int task_cputime_expired(const struct task_cputime *sample,
1323 const struct task_cputime *expires)
1325 if (!cputime_eq(expires->utime, cputime_zero) &&
1326 cputime_ge(sample->utime, expires->utime))
1327 return 1;
1328 if (!cputime_eq(expires->stime, cputime_zero) &&
1329 cputime_ge(cputime_add(sample->utime, sample->stime),
1330 expires->stime))
1331 return 1;
1332 if (expires->sum_exec_runtime != 0 &&
1333 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1334 return 1;
1335 return 0;
1339 * fastpath_timer_check - POSIX CPU timers fast path.
1341 * @tsk: The task (thread) being checked.
1343 * Check the task and thread group timers. If both are zero (there are no
1344 * timers set) return false. Otherwise snapshot the task and thread group
1345 * timers and compare them with the corresponding expiration times. Return
1346 * true if a timer has expired, else return false.
1348 static inline int fastpath_timer_check(struct task_struct *tsk)
1350 struct signal_struct *sig;
1352 /* tsk == current, ensure it is safe to use ->signal/sighand */
1353 if (unlikely(tsk->exit_state))
1354 return 0;
1356 if (!task_cputime_zero(&tsk->cputime_expires)) {
1357 struct task_cputime task_sample = {
1358 .utime = tsk->utime,
1359 .stime = tsk->stime,
1360 .sum_exec_runtime = tsk->se.sum_exec_runtime
1363 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1364 return 1;
1367 sig = tsk->signal;
1368 if (!task_cputime_zero(&sig->cputime_expires)) {
1369 struct task_cputime group_sample;
1371 thread_group_cputimer(tsk, &group_sample);
1372 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1373 return 1;
1376 return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
1380 * This is called from the timer interrupt handler. The irq handler has
1381 * already updated our counts. We need to check if any timers fire now.
1382 * Interrupts are disabled.
1384 void run_posix_cpu_timers(struct task_struct *tsk)
1386 LIST_HEAD(firing);
1387 struct k_itimer *timer, *next;
1389 BUG_ON(!irqs_disabled());
1392 * The fast path checks that there are no expired thread or thread
1393 * group timers. If that's so, just return.
1395 if (!fastpath_timer_check(tsk))
1396 return;
1398 spin_lock(&tsk->sighand->siglock);
1400 * Here we take off tsk->signal->cpu_timers[N] and
1401 * tsk->cpu_timers[N] all the timers that are firing, and
1402 * put them on the firing list.
1404 check_thread_timers(tsk, &firing);
1405 check_process_timers(tsk, &firing);
1408 * We must release these locks before taking any timer's lock.
1409 * There is a potential race with timer deletion here, as the
1410 * siglock now protects our private firing list. We have set
1411 * the firing flag in each timer, so that a deletion attempt
1412 * that gets the timer lock before we do will give it up and
1413 * spin until we've taken care of that timer below.
1415 spin_unlock(&tsk->sighand->siglock);
1418 * Now that all the timers on our list have the firing flag,
1419 * noone will touch their list entries but us. We'll take
1420 * each timer's lock before clearing its firing flag, so no
1421 * timer call will interfere.
1423 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1424 int cpu_firing;
1426 spin_lock(&timer->it_lock);
1427 list_del_init(&timer->it.cpu.entry);
1428 cpu_firing = timer->it.cpu.firing;
1429 timer->it.cpu.firing = 0;
1431 * The firing flag is -1 if we collided with a reset
1432 * of the timer, which already reported this
1433 * almost-firing as an overrun. So don't generate an event.
1435 if (likely(cpu_firing >= 0))
1436 cpu_timer_fire(timer);
1437 spin_unlock(&timer->it_lock);
1442 * Set one of the process-wide special case CPU timers.
1443 * The tsk->sighand->siglock must be held by the caller.
1444 * The *newval argument is relative and we update it to be absolute, *oldval
1445 * is absolute and we update it to be relative.
1447 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1448 cputime_t *newval, cputime_t *oldval)
1450 union cpu_time_count now;
1451 struct list_head *head;
1453 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1454 cpu_timer_sample_group(clock_idx, tsk, &now);
1456 if (oldval) {
1457 if (!cputime_eq(*oldval, cputime_zero)) {
1458 if (cputime_le(*oldval, now.cpu)) {
1459 /* Just about to fire. */
1460 *oldval = jiffies_to_cputime(1);
1461 } else {
1462 *oldval = cputime_sub(*oldval, now.cpu);
1466 if (cputime_eq(*newval, cputime_zero))
1467 return;
1468 *newval = cputime_add(*newval, now.cpu);
1471 * If the RLIMIT_CPU timer will expire before the
1472 * ITIMER_PROF timer, we have nothing else to do.
1474 if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
1475 < cputime_to_secs(*newval))
1476 return;
1480 * Check whether there are any process timers already set to fire
1481 * before this one. If so, we don't have anything more to do.
1483 head = &tsk->signal->cpu_timers[clock_idx];
1484 if (list_empty(head) ||
1485 cputime_ge(list_first_entry(head,
1486 struct cpu_timer_list, entry)->expires.cpu,
1487 *newval)) {
1488 switch (clock_idx) {
1489 case CPUCLOCK_PROF:
1490 tsk->signal->cputime_expires.prof_exp = *newval;
1491 break;
1492 case CPUCLOCK_VIRT:
1493 tsk->signal->cputime_expires.virt_exp = *newval;
1494 break;
1499 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1500 struct timespec *rqtp, struct itimerspec *it)
1502 struct k_itimer timer;
1503 int error;
1506 * Set up a temporary timer and then wait for it to go off.
1508 memset(&timer, 0, sizeof timer);
1509 spin_lock_init(&timer.it_lock);
1510 timer.it_clock = which_clock;
1511 timer.it_overrun = -1;
1512 error = posix_cpu_timer_create(&timer);
1513 timer.it_process = current;
1514 if (!error) {
1515 static struct itimerspec zero_it;
1517 memset(it, 0, sizeof *it);
1518 it->it_value = *rqtp;
1520 spin_lock_irq(&timer.it_lock);
1521 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1522 if (error) {
1523 spin_unlock_irq(&timer.it_lock);
1524 return error;
1527 while (!signal_pending(current)) {
1528 if (timer.it.cpu.expires.sched == 0) {
1530 * Our timer fired and was reset.
1532 spin_unlock_irq(&timer.it_lock);
1533 return 0;
1537 * Block until cpu_timer_fire (or a signal) wakes us.
1539 __set_current_state(TASK_INTERRUPTIBLE);
1540 spin_unlock_irq(&timer.it_lock);
1541 schedule();
1542 spin_lock_irq(&timer.it_lock);
1546 * We were interrupted by a signal.
1548 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1549 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1550 spin_unlock_irq(&timer.it_lock);
1552 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1554 * It actually did fire already.
1556 return 0;
1559 error = -ERESTART_RESTARTBLOCK;
1562 return error;
1565 int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1566 struct timespec *rqtp, struct timespec __user *rmtp)
1568 struct restart_block *restart_block =
1569 &current_thread_info()->restart_block;
1570 struct itimerspec it;
1571 int error;
1574 * Diagnose required errors first.
1576 if (CPUCLOCK_PERTHREAD(which_clock) &&
1577 (CPUCLOCK_PID(which_clock) == 0 ||
1578 CPUCLOCK_PID(which_clock) == current->pid))
1579 return -EINVAL;
1581 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1583 if (error == -ERESTART_RESTARTBLOCK) {
1585 if (flags & TIMER_ABSTIME)
1586 return -ERESTARTNOHAND;
1588 * Report back to the user the time still remaining.
1590 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1591 return -EFAULT;
1593 restart_block->fn = posix_cpu_nsleep_restart;
1594 restart_block->arg0 = which_clock;
1595 restart_block->arg1 = (unsigned long) rmtp;
1596 restart_block->arg2 = rqtp->tv_sec;
1597 restart_block->arg3 = rqtp->tv_nsec;
1599 return error;
1602 long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1604 clockid_t which_clock = restart_block->arg0;
1605 struct timespec __user *rmtp;
1606 struct timespec t;
1607 struct itimerspec it;
1608 int error;
1610 rmtp = (struct timespec __user *) restart_block->arg1;
1611 t.tv_sec = restart_block->arg2;
1612 t.tv_nsec = restart_block->arg3;
1614 restart_block->fn = do_no_restart_syscall;
1615 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1617 if (error == -ERESTART_RESTARTBLOCK) {
1619 * Report back to the user the time still remaining.
1621 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1622 return -EFAULT;
1624 restart_block->fn = posix_cpu_nsleep_restart;
1625 restart_block->arg0 = which_clock;
1626 restart_block->arg1 = (unsigned long) rmtp;
1627 restart_block->arg2 = t.tv_sec;
1628 restart_block->arg3 = t.tv_nsec;
1630 return error;
1635 #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1636 #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1638 static int process_cpu_clock_getres(const clockid_t which_clock,
1639 struct timespec *tp)
1641 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1643 static int process_cpu_clock_get(const clockid_t which_clock,
1644 struct timespec *tp)
1646 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1648 static int process_cpu_timer_create(struct k_itimer *timer)
1650 timer->it_clock = PROCESS_CLOCK;
1651 return posix_cpu_timer_create(timer);
1653 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1654 struct timespec *rqtp,
1655 struct timespec __user *rmtp)
1657 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1659 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1661 return -EINVAL;
1663 static int thread_cpu_clock_getres(const clockid_t which_clock,
1664 struct timespec *tp)
1666 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1668 static int thread_cpu_clock_get(const clockid_t which_clock,
1669 struct timespec *tp)
1671 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1673 static int thread_cpu_timer_create(struct k_itimer *timer)
1675 timer->it_clock = THREAD_CLOCK;
1676 return posix_cpu_timer_create(timer);
1678 static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
1679 struct timespec *rqtp, struct timespec __user *rmtp)
1681 return -EINVAL;
1683 static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
1685 return -EINVAL;
1688 static __init int init_posix_cpu_timers(void)
1690 struct k_clock process = {
1691 .clock_getres = process_cpu_clock_getres,
1692 .clock_get = process_cpu_clock_get,
1693 .clock_set = do_posix_clock_nosettime,
1694 .timer_create = process_cpu_timer_create,
1695 .nsleep = process_cpu_nsleep,
1696 .nsleep_restart = process_cpu_nsleep_restart,
1698 struct k_clock thread = {
1699 .clock_getres = thread_cpu_clock_getres,
1700 .clock_get = thread_cpu_clock_get,
1701 .clock_set = do_posix_clock_nosettime,
1702 .timer_create = thread_cpu_timer_create,
1703 .nsleep = thread_cpu_nsleep,
1704 .nsleep_restart = thread_cpu_nsleep_restart,
1707 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1708 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1710 return 0;
1712 __initcall(init_posix_cpu_timers);