ia64/linux-2.6.18-xen.hg

view kernel/posix-cpu-timers.c @ 912:dd42cdb0ab89

[IA64] Build blktap2 driver by default in x86 builds.

add CONFIG_XEN_BLKDEV_TAP2=y to buildconfigs/linux-defconfig_xen_ia64.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Mon Jun 29 12:09:16 2009 +0900 (2009-06-29)
parents 3e8752eb6d9c
children
line source
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 <asm/uaccess.h>
8 #include <linux/errno.h>
10 static int check_clock(const clockid_t which_clock)
11 {
12 int error = 0;
13 struct task_struct *p;
14 const pid_t pid = CPUCLOCK_PID(which_clock);
16 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
17 return -EINVAL;
19 if (pid == 0)
20 return 0;
22 read_lock(&tasklist_lock);
23 p = find_task_by_pid(pid);
24 if (!p || (CPUCLOCK_PERTHREAD(which_clock) ?
25 p->tgid != current->tgid : p->tgid != pid)) {
26 error = -EINVAL;
27 }
28 read_unlock(&tasklist_lock);
30 return error;
31 }
33 static inline union cpu_time_count
34 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
35 {
36 union cpu_time_count ret;
37 ret.sched = 0; /* high half always zero when .cpu used */
38 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
39 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
40 } else {
41 ret.cpu = timespec_to_cputime(tp);
42 }
43 return ret;
44 }
46 static void sample_to_timespec(const clockid_t which_clock,
47 union cpu_time_count cpu,
48 struct timespec *tp)
49 {
50 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
51 tp->tv_sec = div_long_long_rem(cpu.sched,
52 NSEC_PER_SEC, &tp->tv_nsec);
53 } else {
54 cputime_to_timespec(cpu.cpu, tp);
55 }
56 }
58 static inline int cpu_time_before(const clockid_t which_clock,
59 union cpu_time_count now,
60 union cpu_time_count then)
61 {
62 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
63 return now.sched < then.sched;
64 } else {
65 return cputime_lt(now.cpu, then.cpu);
66 }
67 }
68 static inline void cpu_time_add(const clockid_t which_clock,
69 union cpu_time_count *acc,
70 union cpu_time_count val)
71 {
72 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
73 acc->sched += val.sched;
74 } else {
75 acc->cpu = cputime_add(acc->cpu, val.cpu);
76 }
77 }
78 static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
79 union cpu_time_count a,
80 union cpu_time_count b)
81 {
82 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
83 a.sched -= b.sched;
84 } else {
85 a.cpu = cputime_sub(a.cpu, b.cpu);
86 }
87 return a;
88 }
90 /*
91 * Divide and limit the result to res >= 1
92 *
93 * This is necessary to prevent signal delivery starvation, when the result of
94 * the division would be rounded down to 0.
95 */
96 static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
97 {
98 cputime_t res = cputime_div(time, div);
100 return max_t(cputime_t, res, 1);
101 }
103 /*
104 * Update expiry time from increment, and increase overrun count,
105 * given the current clock sample.
106 */
107 static void bump_cpu_timer(struct k_itimer *timer,
108 union cpu_time_count now)
109 {
110 int i;
112 if (timer->it.cpu.incr.sched == 0)
113 return;
115 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
116 unsigned long long delta, incr;
118 if (now.sched < timer->it.cpu.expires.sched)
119 return;
120 incr = timer->it.cpu.incr.sched;
121 delta = now.sched + incr - timer->it.cpu.expires.sched;
122 /* Don't use (incr*2 < delta), incr*2 might overflow. */
123 for (i = 0; incr < delta - incr; i++)
124 incr = incr << 1;
125 for (; i >= 0; incr >>= 1, i--) {
126 if (delta < incr)
127 continue;
128 timer->it.cpu.expires.sched += incr;
129 timer->it_overrun += 1 << i;
130 delta -= incr;
131 }
132 } else {
133 cputime_t delta, incr;
135 if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
136 return;
137 incr = timer->it.cpu.incr.cpu;
138 delta = cputime_sub(cputime_add(now.cpu, incr),
139 timer->it.cpu.expires.cpu);
140 /* Don't use (incr*2 < delta), incr*2 might overflow. */
141 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
142 incr = cputime_add(incr, incr);
143 for (; i >= 0; incr = cputime_halve(incr), i--) {
144 if (cputime_lt(delta, incr))
145 continue;
146 timer->it.cpu.expires.cpu =
147 cputime_add(timer->it.cpu.expires.cpu, incr);
148 timer->it_overrun += 1 << i;
149 delta = cputime_sub(delta, incr);
150 }
151 }
152 }
154 static inline cputime_t prof_ticks(struct task_struct *p)
155 {
156 return cputime_add(p->utime, p->stime);
157 }
158 static inline cputime_t virt_ticks(struct task_struct *p)
159 {
160 return p->utime;
161 }
162 static inline unsigned long long sched_ns(struct task_struct *p)
163 {
164 return (p == current) ? current_sched_time(p) : p->sched_time;
165 }
167 int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
168 {
169 int error = check_clock(which_clock);
170 if (!error) {
171 tp->tv_sec = 0;
172 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
173 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
174 /*
175 * If sched_clock is using a cycle counter, we
176 * don't have any idea of its true resolution
177 * exported, but it is much more than 1s/HZ.
178 */
179 tp->tv_nsec = 1;
180 }
181 }
182 return error;
183 }
185 int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
186 {
187 /*
188 * You can never reset a CPU clock, but we check for other errors
189 * in the call before failing with EPERM.
190 */
191 int error = check_clock(which_clock);
192 if (error == 0) {
193 error = -EPERM;
194 }
195 return error;
196 }
199 /*
200 * Sample a per-thread clock for the given task.
201 */
202 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
203 union cpu_time_count *cpu)
204 {
205 switch (CPUCLOCK_WHICH(which_clock)) {
206 default:
207 return -EINVAL;
208 case CPUCLOCK_PROF:
209 cpu->cpu = prof_ticks(p);
210 break;
211 case CPUCLOCK_VIRT:
212 cpu->cpu = virt_ticks(p);
213 break;
214 case CPUCLOCK_SCHED:
215 cpu->sched = sched_ns(p);
216 break;
217 }
218 return 0;
219 }
221 /*
222 * Sample a process (thread group) clock for the given group_leader task.
223 * Must be called with tasklist_lock held for reading.
224 * Must be called with tasklist_lock held for reading, and p->sighand->siglock.
225 */
226 static int cpu_clock_sample_group_locked(unsigned int clock_idx,
227 struct task_struct *p,
228 union cpu_time_count *cpu)
229 {
230 struct task_struct *t = p;
231 switch (clock_idx) {
232 default:
233 return -EINVAL;
234 case CPUCLOCK_PROF:
235 cpu->cpu = cputime_add(p->signal->utime, p->signal->stime);
236 do {
237 cpu->cpu = cputime_add(cpu->cpu, prof_ticks(t));
238 t = next_thread(t);
239 } while (t != p);
240 break;
241 case CPUCLOCK_VIRT:
242 cpu->cpu = p->signal->utime;
243 do {
244 cpu->cpu = cputime_add(cpu->cpu, virt_ticks(t));
245 t = next_thread(t);
246 } while (t != p);
247 break;
248 case CPUCLOCK_SCHED:
249 cpu->sched = p->signal->sched_time;
250 /* Add in each other live thread. */
251 while ((t = next_thread(t)) != p) {
252 cpu->sched += t->sched_time;
253 }
254 cpu->sched += sched_ns(p);
255 break;
256 }
257 return 0;
258 }
260 /*
261 * Sample a process (thread group) clock for the given group_leader task.
262 * Must be called with tasklist_lock held for reading.
263 */
264 static int cpu_clock_sample_group(const clockid_t which_clock,
265 struct task_struct *p,
266 union cpu_time_count *cpu)
267 {
268 int ret;
269 unsigned long flags;
270 spin_lock_irqsave(&p->sighand->siglock, flags);
271 ret = cpu_clock_sample_group_locked(CPUCLOCK_WHICH(which_clock), p,
272 cpu);
273 spin_unlock_irqrestore(&p->sighand->siglock, flags);
274 return ret;
275 }
278 int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
279 {
280 const pid_t pid = CPUCLOCK_PID(which_clock);
281 int error = -EINVAL;
282 union cpu_time_count rtn;
284 if (pid == 0) {
285 /*
286 * Special case constant value for our own clocks.
287 * We don't have to do any lookup to find ourselves.
288 */
289 if (CPUCLOCK_PERTHREAD(which_clock)) {
290 /*
291 * Sampling just ourselves we can do with no locking.
292 */
293 error = cpu_clock_sample(which_clock,
294 current, &rtn);
295 } else {
296 read_lock(&tasklist_lock);
297 error = cpu_clock_sample_group(which_clock,
298 current, &rtn);
299 read_unlock(&tasklist_lock);
300 }
301 } else {
302 /*
303 * Find the given PID, and validate that the caller
304 * should be able to see it.
305 */
306 struct task_struct *p;
307 read_lock(&tasklist_lock);
308 p = find_task_by_pid(pid);
309 if (p) {
310 if (CPUCLOCK_PERTHREAD(which_clock)) {
311 if (p->tgid == current->tgid) {
312 error = cpu_clock_sample(which_clock,
313 p, &rtn);
314 }
315 } else if (p->tgid == pid && p->signal) {
316 error = cpu_clock_sample_group(which_clock,
317 p, &rtn);
318 }
319 }
320 read_unlock(&tasklist_lock);
321 }
323 if (error)
324 return error;
325 sample_to_timespec(which_clock, rtn, tp);
326 return 0;
327 }
330 /*
331 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
332 * This is called from sys_timer_create with the new timer already locked.
333 */
334 int posix_cpu_timer_create(struct k_itimer *new_timer)
335 {
336 int ret = 0;
337 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
338 struct task_struct *p;
340 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
341 return -EINVAL;
343 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
344 new_timer->it.cpu.incr.sched = 0;
345 new_timer->it.cpu.expires.sched = 0;
347 read_lock(&tasklist_lock);
348 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
349 if (pid == 0) {
350 p = current;
351 } else {
352 p = find_task_by_pid(pid);
353 if (p && p->tgid != current->tgid)
354 p = NULL;
355 }
356 } else {
357 if (pid == 0) {
358 p = current->group_leader;
359 } else {
360 p = find_task_by_pid(pid);
361 if (p && p->tgid != pid)
362 p = NULL;
363 }
364 }
365 new_timer->it.cpu.task = p;
366 if (p) {
367 get_task_struct(p);
368 } else {
369 ret = -EINVAL;
370 }
371 read_unlock(&tasklist_lock);
373 return ret;
374 }
376 /*
377 * Clean up a CPU-clock timer that is about to be destroyed.
378 * This is called from timer deletion with the timer already locked.
379 * If we return TIMER_RETRY, it's necessary to release the timer's lock
380 * and try again. (This happens when the timer is in the middle of firing.)
381 */
382 int posix_cpu_timer_del(struct k_itimer *timer)
383 {
384 struct task_struct *p = timer->it.cpu.task;
385 int ret = 0;
387 if (likely(p != NULL)) {
388 read_lock(&tasklist_lock);
389 if (unlikely(p->signal == NULL)) {
390 /*
391 * We raced with the reaping of the task.
392 * The deletion should have cleared us off the list.
393 */
394 BUG_ON(!list_empty(&timer->it.cpu.entry));
395 } else {
396 spin_lock(&p->sighand->siglock);
397 if (timer->it.cpu.firing)
398 ret = TIMER_RETRY;
399 else
400 list_del(&timer->it.cpu.entry);
401 spin_unlock(&p->sighand->siglock);
402 }
403 read_unlock(&tasklist_lock);
405 if (!ret)
406 put_task_struct(p);
407 }
409 return ret;
410 }
412 /*
413 * Clean out CPU timers still ticking when a thread exited. The task
414 * pointer is cleared, and the expiry time is replaced with the residual
415 * time for later timer_gettime calls to return.
416 * This must be called with the siglock held.
417 */
418 static void cleanup_timers(struct list_head *head,
419 cputime_t utime, cputime_t stime,
420 unsigned long long sched_time)
421 {
422 struct cpu_timer_list *timer, *next;
423 cputime_t ptime = cputime_add(utime, stime);
425 list_for_each_entry_safe(timer, next, head, entry) {
426 list_del_init(&timer->entry);
427 if (cputime_lt(timer->expires.cpu, ptime)) {
428 timer->expires.cpu = cputime_zero;
429 } else {
430 timer->expires.cpu = cputime_sub(timer->expires.cpu,
431 ptime);
432 }
433 }
435 ++head;
436 list_for_each_entry_safe(timer, next, head, entry) {
437 list_del_init(&timer->entry);
438 if (cputime_lt(timer->expires.cpu, utime)) {
439 timer->expires.cpu = cputime_zero;
440 } else {
441 timer->expires.cpu = cputime_sub(timer->expires.cpu,
442 utime);
443 }
444 }
446 ++head;
447 list_for_each_entry_safe(timer, next, head, entry) {
448 list_del_init(&timer->entry);
449 if (timer->expires.sched < sched_time) {
450 timer->expires.sched = 0;
451 } else {
452 timer->expires.sched -= sched_time;
453 }
454 }
455 }
457 /*
458 * These are both called with the siglock held, when the current thread
459 * is being reaped. When the final (leader) thread in the group is reaped,
460 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
461 */
462 void posix_cpu_timers_exit(struct task_struct *tsk)
463 {
464 cleanup_timers(tsk->cpu_timers,
465 tsk->utime, tsk->stime, tsk->sched_time);
467 }
468 void posix_cpu_timers_exit_group(struct task_struct *tsk)
469 {
470 cleanup_timers(tsk->signal->cpu_timers,
471 cputime_add(tsk->utime, tsk->signal->utime),
472 cputime_add(tsk->stime, tsk->signal->stime),
473 tsk->sched_time + tsk->signal->sched_time);
474 }
477 /*
478 * Set the expiry times of all the threads in the process so one of them
479 * will go off before the process cumulative expiry total is reached.
480 */
481 static void process_timer_rebalance(struct task_struct *p,
482 unsigned int clock_idx,
483 union cpu_time_count expires,
484 union cpu_time_count val)
485 {
486 cputime_t ticks, left;
487 unsigned long long ns, nsleft;
488 struct task_struct *t = p;
489 unsigned int nthreads = atomic_read(&p->signal->live);
491 if (!nthreads)
492 return;
494 switch (clock_idx) {
495 default:
496 BUG();
497 break;
498 case CPUCLOCK_PROF:
499 left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
500 nthreads);
501 do {
502 if (likely(!(t->flags & PF_EXITING))) {
503 ticks = cputime_add(prof_ticks(t), left);
504 if (cputime_eq(t->it_prof_expires,
505 cputime_zero) ||
506 cputime_gt(t->it_prof_expires, ticks)) {
507 t->it_prof_expires = ticks;
508 }
509 }
510 t = next_thread(t);
511 } while (t != p);
512 break;
513 case CPUCLOCK_VIRT:
514 left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
515 nthreads);
516 do {
517 if (likely(!(t->flags & PF_EXITING))) {
518 ticks = cputime_add(virt_ticks(t), left);
519 if (cputime_eq(t->it_virt_expires,
520 cputime_zero) ||
521 cputime_gt(t->it_virt_expires, ticks)) {
522 t->it_virt_expires = ticks;
523 }
524 }
525 t = next_thread(t);
526 } while (t != p);
527 break;
528 case CPUCLOCK_SCHED:
529 nsleft = expires.sched - val.sched;
530 do_div(nsleft, nthreads);
531 nsleft = max_t(unsigned long long, nsleft, 1);
532 do {
533 if (likely(!(t->flags & PF_EXITING))) {
534 ns = t->sched_time + nsleft;
535 if (t->it_sched_expires == 0 ||
536 t->it_sched_expires > ns) {
537 t->it_sched_expires = ns;
538 }
539 }
540 t = next_thread(t);
541 } while (t != p);
542 break;
543 }
544 }
546 static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
547 {
548 /*
549 * That's all for this thread or process.
550 * We leave our residual in expires to be reported.
551 */
552 put_task_struct(timer->it.cpu.task);
553 timer->it.cpu.task = NULL;
554 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
555 timer->it.cpu.expires,
556 now);
557 }
559 /*
560 * Insert the timer on the appropriate list before any timers that
561 * expire later. This must be called with the tasklist_lock held
562 * for reading, and interrupts disabled.
563 */
564 static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
565 {
566 struct task_struct *p = timer->it.cpu.task;
567 struct list_head *head, *listpos;
568 struct cpu_timer_list *const nt = &timer->it.cpu;
569 struct cpu_timer_list *next;
570 unsigned long i;
572 head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
573 p->cpu_timers : p->signal->cpu_timers);
574 head += CPUCLOCK_WHICH(timer->it_clock);
576 BUG_ON(!irqs_disabled());
577 spin_lock(&p->sighand->siglock);
579 listpos = head;
580 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
581 list_for_each_entry(next, head, entry) {
582 if (next->expires.sched > nt->expires.sched)
583 break;
584 listpos = &next->entry;
585 }
586 } else {
587 list_for_each_entry(next, head, entry) {
588 if (cputime_gt(next->expires.cpu, nt->expires.cpu))
589 break;
590 listpos = &next->entry;
591 }
592 }
593 list_add(&nt->entry, listpos);
595 if (listpos == head) {
596 /*
597 * We are the new earliest-expiring timer.
598 * If we are a thread timer, there can always
599 * be a process timer telling us to stop earlier.
600 */
602 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
603 switch (CPUCLOCK_WHICH(timer->it_clock)) {
604 default:
605 BUG();
606 case CPUCLOCK_PROF:
607 if (cputime_eq(p->it_prof_expires,
608 cputime_zero) ||
609 cputime_gt(p->it_prof_expires,
610 nt->expires.cpu))
611 p->it_prof_expires = nt->expires.cpu;
612 break;
613 case CPUCLOCK_VIRT:
614 if (cputime_eq(p->it_virt_expires,
615 cputime_zero) ||
616 cputime_gt(p->it_virt_expires,
617 nt->expires.cpu))
618 p->it_virt_expires = nt->expires.cpu;
619 break;
620 case CPUCLOCK_SCHED:
621 if (p->it_sched_expires == 0 ||
622 p->it_sched_expires > nt->expires.sched)
623 p->it_sched_expires = nt->expires.sched;
624 break;
625 }
626 } else {
627 /*
628 * For a process timer, we must balance
629 * all the live threads' expirations.
630 */
631 switch (CPUCLOCK_WHICH(timer->it_clock)) {
632 default:
633 BUG();
634 case CPUCLOCK_VIRT:
635 if (!cputime_eq(p->signal->it_virt_expires,
636 cputime_zero) &&
637 cputime_lt(p->signal->it_virt_expires,
638 timer->it.cpu.expires.cpu))
639 break;
640 goto rebalance;
641 case CPUCLOCK_PROF:
642 if (!cputime_eq(p->signal->it_prof_expires,
643 cputime_zero) &&
644 cputime_lt(p->signal->it_prof_expires,
645 timer->it.cpu.expires.cpu))
646 break;
647 i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
648 if (i != RLIM_INFINITY &&
649 i <= cputime_to_secs(timer->it.cpu.expires.cpu))
650 break;
651 goto rebalance;
652 case CPUCLOCK_SCHED:
653 rebalance:
654 process_timer_rebalance(
655 timer->it.cpu.task,
656 CPUCLOCK_WHICH(timer->it_clock),
657 timer->it.cpu.expires, now);
658 break;
659 }
660 }
661 }
663 spin_unlock(&p->sighand->siglock);
664 }
666 /*
667 * The timer is locked, fire it and arrange for its reload.
668 */
669 static void cpu_timer_fire(struct k_itimer *timer)
670 {
671 if (unlikely(timer->sigq == NULL)) {
672 /*
673 * This a special case for clock_nanosleep,
674 * not a normal timer from sys_timer_create.
675 */
676 wake_up_process(timer->it_process);
677 timer->it.cpu.expires.sched = 0;
678 } else if (timer->it.cpu.incr.sched == 0) {
679 /*
680 * One-shot timer. Clear it as soon as it's fired.
681 */
682 posix_timer_event(timer, 0);
683 timer->it.cpu.expires.sched = 0;
684 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
685 /*
686 * The signal did not get queued because the signal
687 * was ignored, so we won't get any callback to
688 * reload the timer. But we need to keep it
689 * ticking in case the signal is deliverable next time.
690 */
691 posix_cpu_timer_schedule(timer);
692 }
693 }
695 /*
696 * Guts of sys_timer_settime for CPU timers.
697 * This is called with the timer locked and interrupts disabled.
698 * If we return TIMER_RETRY, it's necessary to release the timer's lock
699 * and try again. (This happens when the timer is in the middle of firing.)
700 */
701 int posix_cpu_timer_set(struct k_itimer *timer, int flags,
702 struct itimerspec *new, struct itimerspec *old)
703 {
704 struct task_struct *p = timer->it.cpu.task;
705 union cpu_time_count old_expires, new_expires, val;
706 int ret;
708 if (unlikely(p == NULL)) {
709 /*
710 * Timer refers to a dead task's clock.
711 */
712 return -ESRCH;
713 }
715 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
717 read_lock(&tasklist_lock);
718 /*
719 * We need the tasklist_lock to protect against reaping that
720 * clears p->signal. If p has just been reaped, we can no
721 * longer get any information about it at all.
722 */
723 if (unlikely(p->signal == NULL)) {
724 read_unlock(&tasklist_lock);
725 put_task_struct(p);
726 timer->it.cpu.task = NULL;
727 return -ESRCH;
728 }
730 /*
731 * Disarm any old timer after extracting its expiry time.
732 */
733 BUG_ON(!irqs_disabled());
735 ret = 0;
736 spin_lock(&p->sighand->siglock);
737 old_expires = timer->it.cpu.expires;
738 if (unlikely(timer->it.cpu.firing)) {
739 timer->it.cpu.firing = -1;
740 ret = TIMER_RETRY;
741 } else
742 list_del_init(&timer->it.cpu.entry);
743 spin_unlock(&p->sighand->siglock);
745 /*
746 * We need to sample the current value to convert the new
747 * value from to relative and absolute, and to convert the
748 * old value from absolute to relative. To set a process
749 * timer, we need a sample to balance the thread expiry
750 * times (in arm_timer). With an absolute time, we must
751 * check if it's already passed. In short, we need a sample.
752 */
753 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
754 cpu_clock_sample(timer->it_clock, p, &val);
755 } else {
756 cpu_clock_sample_group(timer->it_clock, p, &val);
757 }
759 if (old) {
760 if (old_expires.sched == 0) {
761 old->it_value.tv_sec = 0;
762 old->it_value.tv_nsec = 0;
763 } else {
764 /*
765 * Update the timer in case it has
766 * overrun already. If it has,
767 * we'll report it as having overrun
768 * and with the next reloaded timer
769 * already ticking, though we are
770 * swallowing that pending
771 * notification here to install the
772 * new setting.
773 */
774 bump_cpu_timer(timer, val);
775 if (cpu_time_before(timer->it_clock, val,
776 timer->it.cpu.expires)) {
777 old_expires = cpu_time_sub(
778 timer->it_clock,
779 timer->it.cpu.expires, val);
780 sample_to_timespec(timer->it_clock,
781 old_expires,
782 &old->it_value);
783 } else {
784 old->it_value.tv_nsec = 1;
785 old->it_value.tv_sec = 0;
786 }
787 }
788 }
790 if (unlikely(ret)) {
791 /*
792 * We are colliding with the timer actually firing.
793 * Punt after filling in the timer's old value, and
794 * disable this firing since we are already reporting
795 * it as an overrun (thanks to bump_cpu_timer above).
796 */
797 read_unlock(&tasklist_lock);
798 goto out;
799 }
801 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
802 cpu_time_add(timer->it_clock, &new_expires, val);
803 }
805 /*
806 * Install the new expiry time (or zero).
807 * For a timer with no notification action, we don't actually
808 * arm the timer (we'll just fake it for timer_gettime).
809 */
810 timer->it.cpu.expires = new_expires;
811 if (new_expires.sched != 0 &&
812 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
813 cpu_time_before(timer->it_clock, val, new_expires)) {
814 arm_timer(timer, val);
815 }
817 read_unlock(&tasklist_lock);
819 /*
820 * Install the new reload setting, and
821 * set up the signal and overrun bookkeeping.
822 */
823 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
824 &new->it_interval);
826 /*
827 * This acts as a modification timestamp for the timer,
828 * so any automatic reload attempt will punt on seeing
829 * that we have reset the timer manually.
830 */
831 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
832 ~REQUEUE_PENDING;
833 timer->it_overrun_last = 0;
834 timer->it_overrun = -1;
836 if (new_expires.sched != 0 &&
837 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
838 !cpu_time_before(timer->it_clock, val, new_expires)) {
839 /*
840 * The designated time already passed, so we notify
841 * immediately, even if the thread never runs to
842 * accumulate more time on this clock.
843 */
844 cpu_timer_fire(timer);
845 }
847 ret = 0;
848 out:
849 if (old) {
850 sample_to_timespec(timer->it_clock,
851 timer->it.cpu.incr, &old->it_interval);
852 }
853 return ret;
854 }
856 void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
857 {
858 union cpu_time_count now;
859 struct task_struct *p = timer->it.cpu.task;
860 int clear_dead;
862 /*
863 * Easy part: convert the reload time.
864 */
865 sample_to_timespec(timer->it_clock,
866 timer->it.cpu.incr, &itp->it_interval);
868 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
869 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
870 return;
871 }
873 if (unlikely(p == NULL)) {
874 /*
875 * This task already died and the timer will never fire.
876 * In this case, expires is actually the dead value.
877 */
878 dead:
879 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
880 &itp->it_value);
881 return;
882 }
884 /*
885 * Sample the clock to take the difference with the expiry time.
886 */
887 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
888 cpu_clock_sample(timer->it_clock, p, &now);
889 clear_dead = p->exit_state;
890 } else {
891 read_lock(&tasklist_lock);
892 if (unlikely(p->signal == NULL)) {
893 /*
894 * The process has been reaped.
895 * We can't even collect a sample any more.
896 * Call the timer disarmed, nothing else to do.
897 */
898 put_task_struct(p);
899 timer->it.cpu.task = NULL;
900 timer->it.cpu.expires.sched = 0;
901 read_unlock(&tasklist_lock);
902 goto dead;
903 } else {
904 cpu_clock_sample_group(timer->it_clock, p, &now);
905 clear_dead = (unlikely(p->exit_state) &&
906 thread_group_empty(p));
907 }
908 read_unlock(&tasklist_lock);
909 }
911 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
912 if (timer->it.cpu.incr.sched == 0 &&
913 cpu_time_before(timer->it_clock,
914 timer->it.cpu.expires, now)) {
915 /*
916 * Do-nothing timer expired and has no reload,
917 * so it's as if it was never set.
918 */
919 timer->it.cpu.expires.sched = 0;
920 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
921 return;
922 }
923 /*
924 * Account for any expirations and reloads that should
925 * have happened.
926 */
927 bump_cpu_timer(timer, now);
928 }
930 if (unlikely(clear_dead)) {
931 /*
932 * We've noticed that the thread is dead, but
933 * not yet reaped. Take this opportunity to
934 * drop our task ref.
935 */
936 clear_dead_task(timer, now);
937 goto dead;
938 }
940 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
941 sample_to_timespec(timer->it_clock,
942 cpu_time_sub(timer->it_clock,
943 timer->it.cpu.expires, now),
944 &itp->it_value);
945 } else {
946 /*
947 * The timer should have expired already, but the firing
948 * hasn't taken place yet. Say it's just about to expire.
949 */
950 itp->it_value.tv_nsec = 1;
951 itp->it_value.tv_sec = 0;
952 }
953 }
955 /*
956 * Check for any per-thread CPU timers that have fired and move them off
957 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
958 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
959 */
960 static void check_thread_timers(struct task_struct *tsk,
961 struct list_head *firing)
962 {
963 int maxfire;
964 struct list_head *timers = tsk->cpu_timers;
966 maxfire = 20;
967 tsk->it_prof_expires = cputime_zero;
968 while (!list_empty(timers)) {
969 struct cpu_timer_list *t = list_entry(timers->next,
970 struct cpu_timer_list,
971 entry);
972 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
973 tsk->it_prof_expires = t->expires.cpu;
974 break;
975 }
976 t->firing = 1;
977 list_move_tail(&t->entry, firing);
978 }
980 ++timers;
981 maxfire = 20;
982 tsk->it_virt_expires = cputime_zero;
983 while (!list_empty(timers)) {
984 struct cpu_timer_list *t = list_entry(timers->next,
985 struct cpu_timer_list,
986 entry);
987 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
988 tsk->it_virt_expires = t->expires.cpu;
989 break;
990 }
991 t->firing = 1;
992 list_move_tail(&t->entry, firing);
993 }
995 ++timers;
996 maxfire = 20;
997 tsk->it_sched_expires = 0;
998 while (!list_empty(timers)) {
999 struct cpu_timer_list *t = list_entry(timers->next,
1000 struct cpu_timer_list,
1001 entry);
1002 if (!--maxfire || tsk->sched_time < t->expires.sched) {
1003 tsk->it_sched_expires = t->expires.sched;
1004 break;
1006 t->firing = 1;
1007 list_move_tail(&t->entry, firing);
1011 /*
1012 * Check for any per-thread CPU timers that have fired and move them
1013 * off the tsk->*_timers list onto the firing list. Per-thread timers
1014 * have already been taken off.
1015 */
1016 static void check_process_timers(struct task_struct *tsk,
1017 struct list_head *firing)
1019 int maxfire;
1020 struct signal_struct *const sig = tsk->signal;
1021 cputime_t utime, stime, ptime, virt_expires, prof_expires;
1022 unsigned long long sched_time, sched_expires;
1023 struct task_struct *t;
1024 struct list_head *timers = sig->cpu_timers;
1026 /*
1027 * Don't sample the current process CPU clocks if there are no timers.
1028 */
1029 if (list_empty(&timers[CPUCLOCK_PROF]) &&
1030 cputime_eq(sig->it_prof_expires, cputime_zero) &&
1031 sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
1032 list_empty(&timers[CPUCLOCK_VIRT]) &&
1033 cputime_eq(sig->it_virt_expires, cputime_zero) &&
1034 list_empty(&timers[CPUCLOCK_SCHED]))
1035 return;
1037 /*
1038 * Collect the current process totals.
1039 */
1040 utime = sig->utime;
1041 stime = sig->stime;
1042 sched_time = sig->sched_time;
1043 t = tsk;
1044 do {
1045 utime = cputime_add(utime, t->utime);
1046 stime = cputime_add(stime, t->stime);
1047 sched_time += t->sched_time;
1048 t = next_thread(t);
1049 } while (t != tsk);
1050 ptime = cputime_add(utime, stime);
1052 maxfire = 20;
1053 prof_expires = cputime_zero;
1054 while (!list_empty(timers)) {
1055 struct cpu_timer_list *t = list_entry(timers->next,
1056 struct cpu_timer_list,
1057 entry);
1058 if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
1059 prof_expires = t->expires.cpu;
1060 break;
1062 t->firing = 1;
1063 list_move_tail(&t->entry, firing);
1066 ++timers;
1067 maxfire = 20;
1068 virt_expires = cputime_zero;
1069 while (!list_empty(timers)) {
1070 struct cpu_timer_list *t = list_entry(timers->next,
1071 struct cpu_timer_list,
1072 entry);
1073 if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
1074 virt_expires = t->expires.cpu;
1075 break;
1077 t->firing = 1;
1078 list_move_tail(&t->entry, firing);
1081 ++timers;
1082 maxfire = 20;
1083 sched_expires = 0;
1084 while (!list_empty(timers)) {
1085 struct cpu_timer_list *t = list_entry(timers->next,
1086 struct cpu_timer_list,
1087 entry);
1088 if (!--maxfire || sched_time < t->expires.sched) {
1089 sched_expires = t->expires.sched;
1090 break;
1092 t->firing = 1;
1093 list_move_tail(&t->entry, firing);
1096 /*
1097 * Check for the special case process timers.
1098 */
1099 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1100 if (cputime_ge(ptime, sig->it_prof_expires)) {
1101 /* ITIMER_PROF fires and reloads. */
1102 sig->it_prof_expires = sig->it_prof_incr;
1103 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1104 sig->it_prof_expires = cputime_add(
1105 sig->it_prof_expires, ptime);
1107 __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
1109 if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
1110 (cputime_eq(prof_expires, cputime_zero) ||
1111 cputime_lt(sig->it_prof_expires, prof_expires))) {
1112 prof_expires = sig->it_prof_expires;
1115 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1116 if (cputime_ge(utime, sig->it_virt_expires)) {
1117 /* ITIMER_VIRTUAL fires and reloads. */
1118 sig->it_virt_expires = sig->it_virt_incr;
1119 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1120 sig->it_virt_expires = cputime_add(
1121 sig->it_virt_expires, utime);
1123 __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
1125 if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
1126 (cputime_eq(virt_expires, cputime_zero) ||
1127 cputime_lt(sig->it_virt_expires, virt_expires))) {
1128 virt_expires = sig->it_virt_expires;
1131 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
1132 unsigned long psecs = cputime_to_secs(ptime);
1133 cputime_t x;
1134 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
1135 /*
1136 * At the hard limit, we just die.
1137 * No need to calculate anything else now.
1138 */
1139 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1140 return;
1142 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
1143 /*
1144 * At the soft limit, send a SIGXCPU every second.
1145 */
1146 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1147 if (sig->rlim[RLIMIT_CPU].rlim_cur
1148 < sig->rlim[RLIMIT_CPU].rlim_max) {
1149 sig->rlim[RLIMIT_CPU].rlim_cur++;
1152 x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
1153 if (cputime_eq(prof_expires, cputime_zero) ||
1154 cputime_lt(x, prof_expires)) {
1155 prof_expires = x;
1159 if (!cputime_eq(prof_expires, cputime_zero) ||
1160 !cputime_eq(virt_expires, cputime_zero) ||
1161 sched_expires != 0) {
1162 /*
1163 * Rebalance the threads' expiry times for the remaining
1164 * process CPU timers.
1165 */
1167 cputime_t prof_left, virt_left, ticks;
1168 unsigned long long sched_left, sched;
1169 const unsigned int nthreads = atomic_read(&sig->live);
1171 if (!nthreads)
1172 return;
1174 prof_left = cputime_sub(prof_expires, utime);
1175 prof_left = cputime_sub(prof_left, stime);
1176 prof_left = cputime_div_non_zero(prof_left, nthreads);
1177 virt_left = cputime_sub(virt_expires, utime);
1178 virt_left = cputime_div_non_zero(virt_left, nthreads);
1179 if (sched_expires) {
1180 sched_left = sched_expires - sched_time;
1181 do_div(sched_left, nthreads);
1182 sched_left = max_t(unsigned long long, sched_left, 1);
1183 } else {
1184 sched_left = 0;
1186 t = tsk;
1187 do {
1188 if (unlikely(t->flags & PF_EXITING))
1189 continue;
1191 ticks = cputime_add(cputime_add(t->utime, t->stime),
1192 prof_left);
1193 if (!cputime_eq(prof_expires, cputime_zero) &&
1194 (cputime_eq(t->it_prof_expires, cputime_zero) ||
1195 cputime_gt(t->it_prof_expires, ticks))) {
1196 t->it_prof_expires = ticks;
1199 ticks = cputime_add(t->utime, virt_left);
1200 if (!cputime_eq(virt_expires, cputime_zero) &&
1201 (cputime_eq(t->it_virt_expires, cputime_zero) ||
1202 cputime_gt(t->it_virt_expires, ticks))) {
1203 t->it_virt_expires = ticks;
1206 sched = t->sched_time + sched_left;
1207 if (sched_expires && (t->it_sched_expires == 0 ||
1208 t->it_sched_expires > sched)) {
1209 t->it_sched_expires = sched;
1211 } while ((t = next_thread(t)) != tsk);
1215 /*
1216 * This is called from the signal code (via do_schedule_next_timer)
1217 * when the last timer signal was delivered and we have to reload the timer.
1218 */
1219 void posix_cpu_timer_schedule(struct k_itimer *timer)
1221 struct task_struct *p = timer->it.cpu.task;
1222 union cpu_time_count now;
1224 if (unlikely(p == NULL))
1225 /*
1226 * The task was cleaned up already, no future firings.
1227 */
1228 goto out;
1230 /*
1231 * Fetch the current sample and update the timer's expiry time.
1232 */
1233 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1234 cpu_clock_sample(timer->it_clock, p, &now);
1235 bump_cpu_timer(timer, now);
1236 if (unlikely(p->exit_state)) {
1237 clear_dead_task(timer, now);
1238 goto out;
1240 read_lock(&tasklist_lock); /* arm_timer needs it. */
1241 } else {
1242 read_lock(&tasklist_lock);
1243 if (unlikely(p->signal == NULL)) {
1244 /*
1245 * The process has been reaped.
1246 * We can't even collect a sample any more.
1247 */
1248 put_task_struct(p);
1249 timer->it.cpu.task = p = NULL;
1250 timer->it.cpu.expires.sched = 0;
1251 goto out_unlock;
1252 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1253 /*
1254 * We've noticed that the thread is dead, but
1255 * not yet reaped. Take this opportunity to
1256 * drop our task ref.
1257 */
1258 clear_dead_task(timer, now);
1259 goto out_unlock;
1261 cpu_clock_sample_group(timer->it_clock, p, &now);
1262 bump_cpu_timer(timer, now);
1263 /* Leave the tasklist_lock locked for the call below. */
1266 /*
1267 * Now re-arm for the new expiry time.
1268 */
1269 arm_timer(timer, now);
1271 out_unlock:
1272 read_unlock(&tasklist_lock);
1274 out:
1275 timer->it_overrun_last = timer->it_overrun;
1276 timer->it_overrun = -1;
1277 ++timer->it_requeue_pending;
1280 /*
1281 * This is called from the timer interrupt handler. The irq handler has
1282 * already updated our counts. We need to check if any timers fire now.
1283 * Interrupts are disabled.
1284 */
1285 void run_posix_cpu_timers(struct task_struct *tsk)
1287 LIST_HEAD(firing);
1288 struct k_itimer *timer, *next;
1290 BUG_ON(!irqs_disabled());
1292 #define UNEXPIRED(clock) \
1293 (cputime_eq(tsk->it_##clock##_expires, cputime_zero) || \
1294 cputime_lt(clock##_ticks(tsk), tsk->it_##clock##_expires))
1296 if (UNEXPIRED(prof) && UNEXPIRED(virt) &&
1297 (tsk->it_sched_expires == 0 ||
1298 tsk->sched_time < tsk->it_sched_expires))
1299 return;
1301 #undef UNEXPIRED
1303 /*
1304 * Double-check with locks held.
1305 */
1306 read_lock(&tasklist_lock);
1307 if (likely(tsk->signal != NULL)) {
1308 spin_lock(&tsk->sighand->siglock);
1310 /*
1311 * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
1312 * all the timers that are firing, and put them on the firing list.
1313 */
1314 check_thread_timers(tsk, &firing);
1315 check_process_timers(tsk, &firing);
1317 /*
1318 * We must release these locks before taking any timer's lock.
1319 * There is a potential race with timer deletion here, as the
1320 * siglock now protects our private firing list. We have set
1321 * the firing flag in each timer, so that a deletion attempt
1322 * that gets the timer lock before we do will give it up and
1323 * spin until we've taken care of that timer below.
1324 */
1325 spin_unlock(&tsk->sighand->siglock);
1327 read_unlock(&tasklist_lock);
1329 /*
1330 * Now that all the timers on our list have the firing flag,
1331 * noone will touch their list entries but us. We'll take
1332 * each timer's lock before clearing its firing flag, so no
1333 * timer call will interfere.
1334 */
1335 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1336 int firing;
1337 spin_lock(&timer->it_lock);
1338 list_del_init(&timer->it.cpu.entry);
1339 firing = timer->it.cpu.firing;
1340 timer->it.cpu.firing = 0;
1341 /*
1342 * The firing flag is -1 if we collided with a reset
1343 * of the timer, which already reported this
1344 * almost-firing as an overrun. So don't generate an event.
1345 */
1346 if (likely(firing >= 0)) {
1347 cpu_timer_fire(timer);
1349 spin_unlock(&timer->it_lock);
1353 /*
1354 * Set one of the process-wide special case CPU timers.
1355 * The tasklist_lock and tsk->sighand->siglock must be held by the caller.
1356 * The oldval argument is null for the RLIMIT_CPU timer, where *newval is
1357 * absolute; non-null for ITIMER_*, where *newval is relative and we update
1358 * it to be absolute, *oldval is absolute and we update it to be relative.
1359 */
1360 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1361 cputime_t *newval, cputime_t *oldval)
1363 union cpu_time_count now;
1364 struct list_head *head;
1366 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1367 cpu_clock_sample_group_locked(clock_idx, tsk, &now);
1369 if (oldval) {
1370 if (!cputime_eq(*oldval, cputime_zero)) {
1371 if (cputime_le(*oldval, now.cpu)) {
1372 /* Just about to fire. */
1373 *oldval = jiffies_to_cputime(1);
1374 } else {
1375 *oldval = cputime_sub(*oldval, now.cpu);
1379 if (cputime_eq(*newval, cputime_zero))
1380 return;
1381 *newval = cputime_add(*newval, now.cpu);
1383 /*
1384 * If the RLIMIT_CPU timer will expire before the
1385 * ITIMER_PROF timer, we have nothing else to do.
1386 */
1387 if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
1388 < cputime_to_secs(*newval))
1389 return;
1392 /*
1393 * Check whether there are any process timers already set to fire
1394 * before this one. If so, we don't have anything more to do.
1395 */
1396 head = &tsk->signal->cpu_timers[clock_idx];
1397 if (list_empty(head) ||
1398 cputime_ge(list_entry(head->next,
1399 struct cpu_timer_list, entry)->expires.cpu,
1400 *newval)) {
1401 /*
1402 * Rejigger each thread's expiry time so that one will
1403 * notice before we hit the process-cumulative expiry time.
1404 */
1405 union cpu_time_count expires = { .sched = 0 };
1406 expires.cpu = *newval;
1407 process_timer_rebalance(tsk, clock_idx, expires, now);
1411 static long posix_cpu_clock_nanosleep_restart(struct restart_block *);
1413 int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1414 struct timespec *rqtp, struct timespec __user *rmtp)
1416 struct restart_block *restart_block =
1417 &current_thread_info()->restart_block;
1418 struct k_itimer timer;
1419 int error;
1421 /*
1422 * Diagnose required errors first.
1423 */
1424 if (CPUCLOCK_PERTHREAD(which_clock) &&
1425 (CPUCLOCK_PID(which_clock) == 0 ||
1426 CPUCLOCK_PID(which_clock) == current->pid))
1427 return -EINVAL;
1429 /*
1430 * Set up a temporary timer and then wait for it to go off.
1431 */
1432 memset(&timer, 0, sizeof timer);
1433 spin_lock_init(&timer.it_lock);
1434 timer.it_clock = which_clock;
1435 timer.it_overrun = -1;
1436 error = posix_cpu_timer_create(&timer);
1437 timer.it_process = current;
1438 if (!error) {
1439 static struct itimerspec zero_it;
1440 struct itimerspec it = { .it_value = *rqtp,
1441 .it_interval = {} };
1443 spin_lock_irq(&timer.it_lock);
1444 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1445 if (error) {
1446 spin_unlock_irq(&timer.it_lock);
1447 return error;
1450 while (!signal_pending(current)) {
1451 if (timer.it.cpu.expires.sched == 0) {
1452 /*
1453 * Our timer fired and was reset.
1454 */
1455 spin_unlock_irq(&timer.it_lock);
1456 return 0;
1459 /*
1460 * Block until cpu_timer_fire (or a signal) wakes us.
1461 */
1462 __set_current_state(TASK_INTERRUPTIBLE);
1463 spin_unlock_irq(&timer.it_lock);
1464 schedule();
1465 spin_lock_irq(&timer.it_lock);
1468 /*
1469 * We were interrupted by a signal.
1470 */
1471 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1472 posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1473 spin_unlock_irq(&timer.it_lock);
1475 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1476 /*
1477 * It actually did fire already.
1478 */
1479 return 0;
1482 /*
1483 * Report back to the user the time still remaining.
1484 */
1485 if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
1486 copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1487 return -EFAULT;
1489 restart_block->fn = posix_cpu_clock_nanosleep_restart;
1490 /* Caller already set restart_block->arg1 */
1491 restart_block->arg0 = which_clock;
1492 restart_block->arg1 = (unsigned long) rmtp;
1493 restart_block->arg2 = rqtp->tv_sec;
1494 restart_block->arg3 = rqtp->tv_nsec;
1496 error = -ERESTART_RESTARTBLOCK;
1499 return error;
1502 static long
1503 posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
1505 clockid_t which_clock = restart_block->arg0;
1506 struct timespec __user *rmtp;
1507 struct timespec t;
1509 rmtp = (struct timespec __user *) restart_block->arg1;
1510 t.tv_sec = restart_block->arg2;
1511 t.tv_nsec = restart_block->arg3;
1513 restart_block->fn = do_no_restart_syscall;
1514 return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t, rmtp);
1518 #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1519 #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1521 static int process_cpu_clock_getres(const clockid_t which_clock,
1522 struct timespec *tp)
1524 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1526 static int process_cpu_clock_get(const clockid_t which_clock,
1527 struct timespec *tp)
1529 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1531 static int process_cpu_timer_create(struct k_itimer *timer)
1533 timer->it_clock = PROCESS_CLOCK;
1534 return posix_cpu_timer_create(timer);
1536 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1537 struct timespec *rqtp,
1538 struct timespec __user *rmtp)
1540 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1542 static int thread_cpu_clock_getres(const clockid_t which_clock,
1543 struct timespec *tp)
1545 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1547 static int thread_cpu_clock_get(const clockid_t which_clock,
1548 struct timespec *tp)
1550 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1552 static int thread_cpu_timer_create(struct k_itimer *timer)
1554 timer->it_clock = THREAD_CLOCK;
1555 return posix_cpu_timer_create(timer);
1557 static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
1558 struct timespec *rqtp, struct timespec __user *rmtp)
1560 return -EINVAL;
1563 static __init int init_posix_cpu_timers(void)
1565 struct k_clock process = {
1566 .clock_getres = process_cpu_clock_getres,
1567 .clock_get = process_cpu_clock_get,
1568 .clock_set = do_posix_clock_nosettime,
1569 .timer_create = process_cpu_timer_create,
1570 .nsleep = process_cpu_nsleep,
1571 };
1572 struct k_clock thread = {
1573 .clock_getres = thread_cpu_clock_getres,
1574 .clock_get = thread_cpu_clock_get,
1575 .clock_set = do_posix_clock_nosettime,
1576 .timer_create = thread_cpu_timer_create,
1577 .nsleep = thread_cpu_nsleep,
1578 };
1580 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1581 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1583 return 0;
1585 __initcall(init_posix_cpu_timers);