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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/posix-cpu-timers.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'kernel/posix-cpu-timers.c')
-rw-r--r--kernel/posix-cpu-timers.c1559
1 files changed, 1559 insertions, 0 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
new file mode 100644
index 000000000000..ad85d3f0dcc4
--- /dev/null
+++ b/kernel/posix-cpu-timers.c
@@ -0,0 +1,1559 @@
1/*
2 * Implement CPU time clocks for the POSIX clock interface.
3 */
4
5#include <linux/sched.h>
6#include <linux/posix-timers.h>
7#include <asm/uaccess.h>
8#include <linux/errno.h>
9
10static int check_clock(clockid_t which_clock)
11{
12 int error = 0;
13 struct task_struct *p;
14 const pid_t pid = CPUCLOCK_PID(which_clock);
15
16 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
17 return -EINVAL;
18
19 if (pid == 0)
20 return 0;
21
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);
29
30 return error;
31}
32
33static inline union cpu_time_count
34timespec_to_sample(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 = tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
40 } else {
41 ret.cpu = timespec_to_cputime(tp);
42 }
43 return ret;
44}
45
46static void sample_to_timespec(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}
57
58static inline int cpu_time_before(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}
68static inline void cpu_time_add(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}
78static inline union cpu_time_count cpu_time_sub(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}
89
90/*
91 * Update expiry time from increment, and increase overrun count,
92 * given the current clock sample.
93 */
94static inline void bump_cpu_timer(struct k_itimer *timer,
95 union cpu_time_count now)
96{
97 int i;
98
99 if (timer->it.cpu.incr.sched == 0)
100 return;
101
102 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
103 unsigned long long delta, incr;
104
105 if (now.sched < timer->it.cpu.expires.sched)
106 return;
107 incr = timer->it.cpu.incr.sched;
108 delta = now.sched + incr - timer->it.cpu.expires.sched;
109 /* Don't use (incr*2 < delta), incr*2 might overflow. */
110 for (i = 0; incr < delta - incr; i++)
111 incr = incr << 1;
112 for (; i >= 0; incr >>= 1, i--) {
113 if (delta <= incr)
114 continue;
115 timer->it.cpu.expires.sched += incr;
116 timer->it_overrun += 1 << i;
117 delta -= incr;
118 }
119 } else {
120 cputime_t delta, incr;
121
122 if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
123 return;
124 incr = timer->it.cpu.incr.cpu;
125 delta = cputime_sub(cputime_add(now.cpu, incr),
126 timer->it.cpu.expires.cpu);
127 /* Don't use (incr*2 < delta), incr*2 might overflow. */
128 for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
129 incr = cputime_add(incr, incr);
130 for (; i >= 0; incr = cputime_halve(incr), i--) {
131 if (cputime_le(delta, incr))
132 continue;
133 timer->it.cpu.expires.cpu =
134 cputime_add(timer->it.cpu.expires.cpu, incr);
135 timer->it_overrun += 1 << i;
136 delta = cputime_sub(delta, incr);
137 }
138 }
139}
140
141static inline cputime_t prof_ticks(struct task_struct *p)
142{
143 return cputime_add(p->utime, p->stime);
144}
145static inline cputime_t virt_ticks(struct task_struct *p)
146{
147 return p->utime;
148}
149static inline unsigned long long sched_ns(struct task_struct *p)
150{
151 return (p == current) ? current_sched_time(p) : p->sched_time;
152}
153
154int posix_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
155{
156 int error = check_clock(which_clock);
157 if (!error) {
158 tp->tv_sec = 0;
159 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
160 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
161 /*
162 * If sched_clock is using a cycle counter, we
163 * don't have any idea of its true resolution
164 * exported, but it is much more than 1s/HZ.
165 */
166 tp->tv_nsec = 1;
167 }
168 }
169 return error;
170}
171
172int posix_cpu_clock_set(clockid_t which_clock, const struct timespec *tp)
173{
174 /*
175 * You can never reset a CPU clock, but we check for other errors
176 * in the call before failing with EPERM.
177 */
178 int error = check_clock(which_clock);
179 if (error == 0) {
180 error = -EPERM;
181 }
182 return error;
183}
184
185
186/*
187 * Sample a per-thread clock for the given task.
188 */
189static int cpu_clock_sample(clockid_t which_clock, struct task_struct *p,
190 union cpu_time_count *cpu)
191{
192 switch (CPUCLOCK_WHICH(which_clock)) {
193 default:
194 return -EINVAL;
195 case CPUCLOCK_PROF:
196 cpu->cpu = prof_ticks(p);
197 break;
198 case CPUCLOCK_VIRT:
199 cpu->cpu = virt_ticks(p);
200 break;
201 case CPUCLOCK_SCHED:
202 cpu->sched = sched_ns(p);
203 break;
204 }
205 return 0;
206}
207
208/*
209 * Sample a process (thread group) clock for the given group_leader task.
210 * Must be called with tasklist_lock held for reading.
211 * Must be called with tasklist_lock held for reading, and p->sighand->siglock.
212 */
213static int cpu_clock_sample_group_locked(unsigned int clock_idx,
214 struct task_struct *p,
215 union cpu_time_count *cpu)
216{
217 struct task_struct *t = p;
218 switch (clock_idx) {
219 default:
220 return -EINVAL;
221 case CPUCLOCK_PROF:
222 cpu->cpu = cputime_add(p->signal->utime, p->signal->stime);
223 do {
224 cpu->cpu = cputime_add(cpu->cpu, prof_ticks(t));
225 t = next_thread(t);
226 } while (t != p);
227 break;
228 case CPUCLOCK_VIRT:
229 cpu->cpu = p->signal->utime;
230 do {
231 cpu->cpu = cputime_add(cpu->cpu, virt_ticks(t));
232 t = next_thread(t);
233 } while (t != p);
234 break;
235 case CPUCLOCK_SCHED:
236 cpu->sched = p->signal->sched_time;
237 /* Add in each other live thread. */
238 while ((t = next_thread(t)) != p) {
239 cpu->sched += t->sched_time;
240 }
241 if (p->tgid == current->tgid) {
242 /*
243 * We're sampling ourselves, so include the
244 * cycles not yet banked. We still omit
245 * other threads running on other CPUs,
246 * so the total can always be behind as
247 * much as max(nthreads-1,ncpus) * (NSEC_PER_SEC/HZ).
248 */
249 cpu->sched += current_sched_time(current);
250 } else {
251 cpu->sched += p->sched_time;
252 }
253 break;
254 }
255 return 0;
256}
257
258/*
259 * Sample a process (thread group) clock for the given group_leader task.
260 * Must be called with tasklist_lock held for reading.
261 */
262static int cpu_clock_sample_group(clockid_t which_clock,
263 struct task_struct *p,
264 union cpu_time_count *cpu)
265{
266 int ret;
267 unsigned long flags;
268 spin_lock_irqsave(&p->sighand->siglock, flags);
269 ret = cpu_clock_sample_group_locked(CPUCLOCK_WHICH(which_clock), p,
270 cpu);
271 spin_unlock_irqrestore(&p->sighand->siglock, flags);
272 return ret;
273}
274
275
276int posix_cpu_clock_get(clockid_t which_clock, struct timespec *tp)
277{
278 const pid_t pid = CPUCLOCK_PID(which_clock);
279 int error = -EINVAL;
280 union cpu_time_count rtn;
281
282 if (pid == 0) {
283 /*
284 * Special case constant value for our own clocks.
285 * We don't have to do any lookup to find ourselves.
286 */
287 if (CPUCLOCK_PERTHREAD(which_clock)) {
288 /*
289 * Sampling just ourselves we can do with no locking.
290 */
291 error = cpu_clock_sample(which_clock,
292 current, &rtn);
293 } else {
294 read_lock(&tasklist_lock);
295 error = cpu_clock_sample_group(which_clock,
296 current, &rtn);
297 read_unlock(&tasklist_lock);
298 }
299 } else {
300 /*
301 * Find the given PID, and validate that the caller
302 * should be able to see it.
303 */
304 struct task_struct *p;
305 read_lock(&tasklist_lock);
306 p = find_task_by_pid(pid);
307 if (p) {
308 if (CPUCLOCK_PERTHREAD(which_clock)) {
309 if (p->tgid == current->tgid) {
310 error = cpu_clock_sample(which_clock,
311 p, &rtn);
312 }
313 } else if (p->tgid == pid && p->signal) {
314 error = cpu_clock_sample_group(which_clock,
315 p, &rtn);
316 }
317 }
318 read_unlock(&tasklist_lock);
319 }
320
321 if (error)
322 return error;
323 sample_to_timespec(which_clock, rtn, tp);
324 return 0;
325}
326
327
328/*
329 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
330 * This is called from sys_timer_create with the new timer already locked.
331 */
332int posix_cpu_timer_create(struct k_itimer *new_timer)
333{
334 int ret = 0;
335 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
336 struct task_struct *p;
337
338 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
339 return -EINVAL;
340
341 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
342 new_timer->it.cpu.incr.sched = 0;
343 new_timer->it.cpu.expires.sched = 0;
344
345 read_lock(&tasklist_lock);
346 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
347 if (pid == 0) {
348 p = current;
349 } else {
350 p = find_task_by_pid(pid);
351 if (p && p->tgid != current->tgid)
352 p = NULL;
353 }
354 } else {
355 if (pid == 0) {
356 p = current->group_leader;
357 } else {
358 p = find_task_by_pid(pid);
359 if (p && p->tgid != pid)
360 p = NULL;
361 }
362 }
363 new_timer->it.cpu.task = p;
364 if (p) {
365 get_task_struct(p);
366 } else {
367 ret = -EINVAL;
368 }
369 read_unlock(&tasklist_lock);
370
371 return ret;
372}
373
374/*
375 * Clean up a CPU-clock timer that is about to be destroyed.
376 * This is called from timer deletion with the timer already locked.
377 * If we return TIMER_RETRY, it's necessary to release the timer's lock
378 * and try again. (This happens when the timer is in the middle of firing.)
379 */
380int posix_cpu_timer_del(struct k_itimer *timer)
381{
382 struct task_struct *p = timer->it.cpu.task;
383
384 if (timer->it.cpu.firing)
385 return TIMER_RETRY;
386
387 if (unlikely(p == NULL))
388 return 0;
389
390 if (!list_empty(&timer->it.cpu.entry)) {
391 read_lock(&tasklist_lock);
392 if (unlikely(p->signal == NULL)) {
393 /*
394 * We raced with the reaping of the task.
395 * The deletion should have cleared us off the list.
396 */
397 BUG_ON(!list_empty(&timer->it.cpu.entry));
398 } else {
399 /*
400 * Take us off the task's timer list.
401 */
402 spin_lock(&p->sighand->siglock);
403 list_del(&timer->it.cpu.entry);
404 spin_unlock(&p->sighand->siglock);
405 }
406 read_unlock(&tasklist_lock);
407 }
408 put_task_struct(p);
409
410 return 0;
411}
412
413/*
414 * Clean out CPU timers still ticking when a thread exited. The task
415 * pointer is cleared, and the expiry time is replaced with the residual
416 * time for later timer_gettime calls to return.
417 * This must be called with the siglock held.
418 */
419static void cleanup_timers(struct list_head *head,
420 cputime_t utime, cputime_t stime,
421 unsigned long long sched_time)
422{
423 struct cpu_timer_list *timer, *next;
424 cputime_t ptime = cputime_add(utime, stime);
425
426 list_for_each_entry_safe(timer, next, head, entry) {
427 timer->task = NULL;
428 list_del_init(&timer->entry);
429 if (cputime_lt(timer->expires.cpu, ptime)) {
430 timer->expires.cpu = cputime_zero;
431 } else {
432 timer->expires.cpu = cputime_sub(timer->expires.cpu,
433 ptime);
434 }
435 }
436
437 ++head;
438 list_for_each_entry_safe(timer, next, head, entry) {
439 timer->task = NULL;
440 list_del_init(&timer->entry);
441 if (cputime_lt(timer->expires.cpu, utime)) {
442 timer->expires.cpu = cputime_zero;
443 } else {
444 timer->expires.cpu = cputime_sub(timer->expires.cpu,
445 utime);
446 }
447 }
448
449 ++head;
450 list_for_each_entry_safe(timer, next, head, entry) {
451 timer->task = NULL;
452 list_del_init(&timer->entry);
453 if (timer->expires.sched < sched_time) {
454 timer->expires.sched = 0;
455 } else {
456 timer->expires.sched -= sched_time;
457 }
458 }
459}
460
461/*
462 * These are both called with the siglock held, when the current thread
463 * is being reaped. When the final (leader) thread in the group is reaped,
464 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
465 */
466void posix_cpu_timers_exit(struct task_struct *tsk)
467{
468 cleanup_timers(tsk->cpu_timers,
469 tsk->utime, tsk->stime, tsk->sched_time);
470
471}
472void posix_cpu_timers_exit_group(struct task_struct *tsk)
473{
474 cleanup_timers(tsk->signal->cpu_timers,
475 cputime_add(tsk->utime, tsk->signal->utime),
476 cputime_add(tsk->stime, tsk->signal->stime),
477 tsk->sched_time + tsk->signal->sched_time);
478}
479
480
481/*
482 * Set the expiry times of all the threads in the process so one of them
483 * will go off before the process cumulative expiry total is reached.
484 */
485static void process_timer_rebalance(struct task_struct *p,
486 unsigned int clock_idx,
487 union cpu_time_count expires,
488 union cpu_time_count val)
489{
490 cputime_t ticks, left;
491 unsigned long long ns, nsleft;
492 struct task_struct *t = p;
493 unsigned int nthreads = atomic_read(&p->signal->live);
494
495 switch (clock_idx) {
496 default:
497 BUG();
498 break;
499 case CPUCLOCK_PROF:
500 left = cputime_div(cputime_sub(expires.cpu, val.cpu),
501 nthreads);
502 do {
503 if (!unlikely(t->exit_state)) {
504 ticks = cputime_add(prof_ticks(t), left);
505 if (cputime_eq(t->it_prof_expires,
506 cputime_zero) ||
507 cputime_gt(t->it_prof_expires, ticks)) {
508 t->it_prof_expires = ticks;
509 }
510 }
511 t = next_thread(t);
512 } while (t != p);
513 break;
514 case CPUCLOCK_VIRT:
515 left = cputime_div(cputime_sub(expires.cpu, val.cpu),
516 nthreads);
517 do {
518 if (!unlikely(t->exit_state)) {
519 ticks = cputime_add(virt_ticks(t), left);
520 if (cputime_eq(t->it_virt_expires,
521 cputime_zero) ||
522 cputime_gt(t->it_virt_expires, ticks)) {
523 t->it_virt_expires = ticks;
524 }
525 }
526 t = next_thread(t);
527 } while (t != p);
528 break;
529 case CPUCLOCK_SCHED:
530 nsleft = expires.sched - val.sched;
531 do_div(nsleft, nthreads);
532 do {
533 if (!unlikely(t->exit_state)) {
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}
545
546static 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}
558
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 */
564static 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;
571
572 head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
573 p->cpu_timers : p->signal->cpu_timers);
574 head += CPUCLOCK_WHICH(timer->it_clock);
575
576 BUG_ON(!irqs_disabled());
577 spin_lock(&p->sighand->siglock);
578
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 listpos = &next->entry;
584 break;
585 }
586 }
587 } else {
588 list_for_each_entry(next, head, entry) {
589 if (cputime_gt(next->expires.cpu, nt->expires.cpu)) {
590 listpos = &next->entry;
591 break;
592 }
593 }
594 }
595 list_add(&nt->entry, listpos);
596
597 if (listpos == head) {
598 /*
599 * We are the new earliest-expiring timer.
600 * If we are a thread timer, there can always
601 * be a process timer telling us to stop earlier.
602 */
603
604 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
605 switch (CPUCLOCK_WHICH(timer->it_clock)) {
606 default:
607 BUG();
608 case CPUCLOCK_PROF:
609 if (cputime_eq(p->it_prof_expires,
610 cputime_zero) ||
611 cputime_gt(p->it_prof_expires,
612 nt->expires.cpu))
613 p->it_prof_expires = nt->expires.cpu;
614 break;
615 case CPUCLOCK_VIRT:
616 if (cputime_eq(p->it_virt_expires,
617 cputime_zero) ||
618 cputime_gt(p->it_virt_expires,
619 nt->expires.cpu))
620 p->it_virt_expires = nt->expires.cpu;
621 break;
622 case CPUCLOCK_SCHED:
623 if (p->it_sched_expires == 0 ||
624 p->it_sched_expires > nt->expires.sched)
625 p->it_sched_expires = nt->expires.sched;
626 break;
627 }
628 } else {
629 /*
630 * For a process timer, we must balance
631 * all the live threads' expirations.
632 */
633 switch (CPUCLOCK_WHICH(timer->it_clock)) {
634 default:
635 BUG();
636 case CPUCLOCK_VIRT:
637 if (!cputime_eq(p->signal->it_virt_expires,
638 cputime_zero) &&
639 cputime_lt(p->signal->it_virt_expires,
640 timer->it.cpu.expires.cpu))
641 break;
642 goto rebalance;
643 case CPUCLOCK_PROF:
644 if (!cputime_eq(p->signal->it_prof_expires,
645 cputime_zero) &&
646 cputime_lt(p->signal->it_prof_expires,
647 timer->it.cpu.expires.cpu))
648 break;
649 i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
650 if (i != RLIM_INFINITY &&
651 i <= cputime_to_secs(timer->it.cpu.expires.cpu))
652 break;
653 goto rebalance;
654 case CPUCLOCK_SCHED:
655 rebalance:
656 process_timer_rebalance(
657 timer->it.cpu.task,
658 CPUCLOCK_WHICH(timer->it_clock),
659 timer->it.cpu.expires, now);
660 break;
661 }
662 }
663 }
664
665 spin_unlock(&p->sighand->siglock);
666}
667
668/*
669 * The timer is locked, fire it and arrange for its reload.
670 */
671static void cpu_timer_fire(struct k_itimer *timer)
672{
673 if (unlikely(timer->sigq == NULL)) {
674 /*
675 * This a special case for clock_nanosleep,
676 * not a normal timer from sys_timer_create.
677 */
678 wake_up_process(timer->it_process);
679 timer->it.cpu.expires.sched = 0;
680 } else if (timer->it.cpu.incr.sched == 0) {
681 /*
682 * One-shot timer. Clear it as soon as it's fired.
683 */
684 posix_timer_event(timer, 0);
685 timer->it.cpu.expires.sched = 0;
686 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
687 /*
688 * The signal did not get queued because the signal
689 * was ignored, so we won't get any callback to
690 * reload the timer. But we need to keep it
691 * ticking in case the signal is deliverable next time.
692 */
693 posix_cpu_timer_schedule(timer);
694 }
695}
696
697/*
698 * Guts of sys_timer_settime for CPU timers.
699 * This is called with the timer locked and interrupts disabled.
700 * If we return TIMER_RETRY, it's necessary to release the timer's lock
701 * and try again. (This happens when the timer is in the middle of firing.)
702 */
703int posix_cpu_timer_set(struct k_itimer *timer, int flags,
704 struct itimerspec *new, struct itimerspec *old)
705{
706 struct task_struct *p = timer->it.cpu.task;
707 union cpu_time_count old_expires, new_expires, val;
708 int ret;
709
710 if (unlikely(p == NULL)) {
711 /*
712 * Timer refers to a dead task's clock.
713 */
714 return -ESRCH;
715 }
716
717 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
718
719 read_lock(&tasklist_lock);
720 /*
721 * We need the tasklist_lock to protect against reaping that
722 * clears p->signal. If p has just been reaped, we can no
723 * longer get any information about it at all.
724 */
725 if (unlikely(p->signal == NULL)) {
726 read_unlock(&tasklist_lock);
727 put_task_struct(p);
728 timer->it.cpu.task = NULL;
729 return -ESRCH;
730 }
731
732 /*
733 * Disarm any old timer after extracting its expiry time.
734 */
735 BUG_ON(!irqs_disabled());
736 spin_lock(&p->sighand->siglock);
737 old_expires = timer->it.cpu.expires;
738 list_del_init(&timer->it.cpu.entry);
739 spin_unlock(&p->sighand->siglock);
740
741 /*
742 * We need to sample the current value to convert the new
743 * value from to relative and absolute, and to convert the
744 * old value from absolute to relative. To set a process
745 * timer, we need a sample to balance the thread expiry
746 * times (in arm_timer). With an absolute time, we must
747 * check if it's already passed. In short, we need a sample.
748 */
749 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
750 cpu_clock_sample(timer->it_clock, p, &val);
751 } else {
752 cpu_clock_sample_group(timer->it_clock, p, &val);
753 }
754
755 if (old) {
756 if (old_expires.sched == 0) {
757 old->it_value.tv_sec = 0;
758 old->it_value.tv_nsec = 0;
759 } else {
760 /*
761 * Update the timer in case it has
762 * overrun already. If it has,
763 * we'll report it as having overrun
764 * and with the next reloaded timer
765 * already ticking, though we are
766 * swallowing that pending
767 * notification here to install the
768 * new setting.
769 */
770 bump_cpu_timer(timer, val);
771 if (cpu_time_before(timer->it_clock, val,
772 timer->it.cpu.expires)) {
773 old_expires = cpu_time_sub(
774 timer->it_clock,
775 timer->it.cpu.expires, val);
776 sample_to_timespec(timer->it_clock,
777 old_expires,
778 &old->it_value);
779 } else {
780 old->it_value.tv_nsec = 1;
781 old->it_value.tv_sec = 0;
782 }
783 }
784 }
785
786 if (unlikely(timer->it.cpu.firing)) {
787 /*
788 * We are colliding with the timer actually firing.
789 * Punt after filling in the timer's old value, and
790 * disable this firing since we are already reporting
791 * it as an overrun (thanks to bump_cpu_timer above).
792 */
793 read_unlock(&tasklist_lock);
794 timer->it.cpu.firing = -1;
795 ret = TIMER_RETRY;
796 goto out;
797 }
798
799 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
800 cpu_time_add(timer->it_clock, &new_expires, val);
801 }
802
803 /*
804 * Install the new expiry time (or zero).
805 * For a timer with no notification action, we don't actually
806 * arm the timer (we'll just fake it for timer_gettime).
807 */
808 timer->it.cpu.expires = new_expires;
809 if (new_expires.sched != 0 &&
810 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
811 cpu_time_before(timer->it_clock, val, new_expires)) {
812 arm_timer(timer, val);
813 }
814
815 read_unlock(&tasklist_lock);
816
817 /*
818 * Install the new reload setting, and
819 * set up the signal and overrun bookkeeping.
820 */
821 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
822 &new->it_interval);
823
824 /*
825 * This acts as a modification timestamp for the timer,
826 * so any automatic reload attempt will punt on seeing
827 * that we have reset the timer manually.
828 */
829 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
830 ~REQUEUE_PENDING;
831 timer->it_overrun_last = 0;
832 timer->it_overrun = -1;
833
834 if (new_expires.sched != 0 &&
835 (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
836 !cpu_time_before(timer->it_clock, val, new_expires)) {
837 /*
838 * The designated time already passed, so we notify
839 * immediately, even if the thread never runs to
840 * accumulate more time on this clock.
841 */
842 cpu_timer_fire(timer);
843 }
844
845 ret = 0;
846 out:
847 if (old) {
848 sample_to_timespec(timer->it_clock,
849 timer->it.cpu.incr, &old->it_interval);
850 }
851 return ret;
852}
853
854void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
855{
856 union cpu_time_count now;
857 struct task_struct *p = timer->it.cpu.task;
858 int clear_dead;
859
860 /*
861 * Easy part: convert the reload time.
862 */
863 sample_to_timespec(timer->it_clock,
864 timer->it.cpu.incr, &itp->it_interval);
865
866 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
867 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
868 return;
869 }
870
871 if (unlikely(p == NULL)) {
872 /*
873 * This task already died and the timer will never fire.
874 * In this case, expires is actually the dead value.
875 */
876 dead:
877 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
878 &itp->it_value);
879 return;
880 }
881
882 /*
883 * Sample the clock to take the difference with the expiry time.
884 */
885 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
886 cpu_clock_sample(timer->it_clock, p, &now);
887 clear_dead = p->exit_state;
888 } else {
889 read_lock(&tasklist_lock);
890 if (unlikely(p->signal == NULL)) {
891 /*
892 * The process has been reaped.
893 * We can't even collect a sample any more.
894 * Call the timer disarmed, nothing else to do.
895 */
896 put_task_struct(p);
897 timer->it.cpu.task = NULL;
898 timer->it.cpu.expires.sched = 0;
899 read_unlock(&tasklist_lock);
900 goto dead;
901 } else {
902 cpu_clock_sample_group(timer->it_clock, p, &now);
903 clear_dead = (unlikely(p->exit_state) &&
904 thread_group_empty(p));
905 }
906 read_unlock(&tasklist_lock);
907 }
908
909 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
910 if (timer->it.cpu.incr.sched == 0 &&
911 cpu_time_before(timer->it_clock,
912 timer->it.cpu.expires, now)) {
913 /*
914 * Do-nothing timer expired and has no reload,
915 * so it's as if it was never set.
916 */
917 timer->it.cpu.expires.sched = 0;
918 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
919 return;
920 }
921 /*
922 * Account for any expirations and reloads that should
923 * have happened.
924 */
925 bump_cpu_timer(timer, now);
926 }
927
928 if (unlikely(clear_dead)) {
929 /*
930 * We've noticed that the thread is dead, but
931 * not yet reaped. Take this opportunity to
932 * drop our task ref.
933 */
934 clear_dead_task(timer, now);
935 goto dead;
936 }
937
938 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
939 sample_to_timespec(timer->it_clock,
940 cpu_time_sub(timer->it_clock,
941 timer->it.cpu.expires, now),
942 &itp->it_value);
943 } else {
944 /*
945 * The timer should have expired already, but the firing
946 * hasn't taken place yet. Say it's just about to expire.
947 */
948 itp->it_value.tv_nsec = 1;
949 itp->it_value.tv_sec = 0;
950 }
951}
952
953/*
954 * Check for any per-thread CPU timers that have fired and move them off
955 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
956 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
957 */
958static void check_thread_timers(struct task_struct *tsk,
959 struct list_head *firing)
960{
961 struct list_head *timers = tsk->cpu_timers;
962
963 tsk->it_prof_expires = cputime_zero;
964 while (!list_empty(timers)) {
965 struct cpu_timer_list *t = list_entry(timers->next,
966 struct cpu_timer_list,
967 entry);
968 if (cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
969 tsk->it_prof_expires = t->expires.cpu;
970 break;
971 }
972 t->firing = 1;
973 list_move_tail(&t->entry, firing);
974 }
975
976 ++timers;
977 tsk->it_virt_expires = cputime_zero;
978 while (!list_empty(timers)) {
979 struct cpu_timer_list *t = list_entry(timers->next,
980 struct cpu_timer_list,
981 entry);
982 if (cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
983 tsk->it_virt_expires = t->expires.cpu;
984 break;
985 }
986 t->firing = 1;
987 list_move_tail(&t->entry, firing);
988 }
989
990 ++timers;
991 tsk->it_sched_expires = 0;
992 while (!list_empty(timers)) {
993 struct cpu_timer_list *t = list_entry(timers->next,
994 struct cpu_timer_list,
995 entry);
996 if (tsk->sched_time < t->expires.sched) {
997 tsk->it_sched_expires = t->expires.sched;
998 break;
999 }
1000 t->firing = 1;
1001 list_move_tail(&t->entry, firing);
1002 }
1003}
1004
1005/*
1006 * Check for any per-thread CPU timers that have fired and move them
1007 * off the tsk->*_timers list onto the firing list. Per-thread timers
1008 * have already been taken off.
1009 */
1010static void check_process_timers(struct task_struct *tsk,
1011 struct list_head *firing)
1012{
1013 struct signal_struct *const sig = tsk->signal;
1014 cputime_t utime, stime, ptime, virt_expires, prof_expires;
1015 unsigned long long sched_time, sched_expires;
1016 struct task_struct *t;
1017 struct list_head *timers = sig->cpu_timers;
1018
1019 /*
1020 * Don't sample the current process CPU clocks if there are no timers.
1021 */
1022 if (list_empty(&timers[CPUCLOCK_PROF]) &&
1023 cputime_eq(sig->it_prof_expires, cputime_zero) &&
1024 sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
1025 list_empty(&timers[CPUCLOCK_VIRT]) &&
1026 cputime_eq(sig->it_virt_expires, cputime_zero) &&
1027 list_empty(&timers[CPUCLOCK_SCHED]))
1028 return;
1029
1030 /*
1031 * Collect the current process totals.
1032 */
1033 utime = sig->utime;
1034 stime = sig->stime;
1035 sched_time = sig->sched_time;
1036 t = tsk;
1037 do {
1038 utime = cputime_add(utime, t->utime);
1039 stime = cputime_add(stime, t->stime);
1040 sched_time += t->sched_time;
1041 t = next_thread(t);
1042 } while (t != tsk);
1043 ptime = cputime_add(utime, stime);
1044
1045 prof_expires = cputime_zero;
1046 while (!list_empty(timers)) {
1047 struct cpu_timer_list *t = list_entry(timers->next,
1048 struct cpu_timer_list,
1049 entry);
1050 if (cputime_lt(ptime, t->expires.cpu)) {
1051 prof_expires = t->expires.cpu;
1052 break;
1053 }
1054 t->firing = 1;
1055 list_move_tail(&t->entry, firing);
1056 }
1057
1058 ++timers;
1059 virt_expires = cputime_zero;
1060 while (!list_empty(timers)) {
1061 struct cpu_timer_list *t = list_entry(timers->next,
1062 struct cpu_timer_list,
1063 entry);
1064 if (cputime_lt(utime, t->expires.cpu)) {
1065 virt_expires = t->expires.cpu;
1066 break;
1067 }
1068 t->firing = 1;
1069 list_move_tail(&t->entry, firing);
1070 }
1071
1072 ++timers;
1073 sched_expires = 0;
1074 while (!list_empty(timers)) {
1075 struct cpu_timer_list *t = list_entry(timers->next,
1076 struct cpu_timer_list,
1077 entry);
1078 if (sched_time < t->expires.sched) {
1079 sched_expires = t->expires.sched;
1080 break;
1081 }
1082 t->firing = 1;
1083 list_move_tail(&t->entry, firing);
1084 }
1085
1086 /*
1087 * Check for the special case process timers.
1088 */
1089 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1090 if (cputime_ge(ptime, sig->it_prof_expires)) {
1091 /* ITIMER_PROF fires and reloads. */
1092 sig->it_prof_expires = sig->it_prof_incr;
1093 if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
1094 sig->it_prof_expires = cputime_add(
1095 sig->it_prof_expires, ptime);
1096 }
1097 __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
1098 }
1099 if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
1100 (cputime_eq(prof_expires, cputime_zero) ||
1101 cputime_lt(sig->it_prof_expires, prof_expires))) {
1102 prof_expires = sig->it_prof_expires;
1103 }
1104 }
1105 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1106 if (cputime_ge(utime, sig->it_virt_expires)) {
1107 /* ITIMER_VIRTUAL fires and reloads. */
1108 sig->it_virt_expires = sig->it_virt_incr;
1109 if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
1110 sig->it_virt_expires = cputime_add(
1111 sig->it_virt_expires, utime);
1112 }
1113 __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
1114 }
1115 if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
1116 (cputime_eq(virt_expires, cputime_zero) ||
1117 cputime_lt(sig->it_virt_expires, virt_expires))) {
1118 virt_expires = sig->it_virt_expires;
1119 }
1120 }
1121 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
1122 unsigned long psecs = cputime_to_secs(ptime);
1123 cputime_t x;
1124 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
1125 /*
1126 * At the hard limit, we just die.
1127 * No need to calculate anything else now.
1128 */
1129 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1130 return;
1131 }
1132 if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
1133 /*
1134 * At the soft limit, send a SIGXCPU every second.
1135 */
1136 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1137 if (sig->rlim[RLIMIT_CPU].rlim_cur
1138 < sig->rlim[RLIMIT_CPU].rlim_max) {
1139 sig->rlim[RLIMIT_CPU].rlim_cur++;
1140 }
1141 }
1142 x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
1143 if (cputime_eq(prof_expires, cputime_zero) ||
1144 cputime_lt(x, prof_expires)) {
1145 prof_expires = x;
1146 }
1147 }
1148
1149 if (!cputime_eq(prof_expires, cputime_zero) ||
1150 !cputime_eq(virt_expires, cputime_zero) ||
1151 sched_expires != 0) {
1152 /*
1153 * Rebalance the threads' expiry times for the remaining
1154 * process CPU timers.
1155 */
1156
1157 cputime_t prof_left, virt_left, ticks;
1158 unsigned long long sched_left, sched;
1159 const unsigned int nthreads = atomic_read(&sig->live);
1160
1161 prof_left = cputime_sub(prof_expires, utime);
1162 prof_left = cputime_sub(prof_left, stime);
1163 prof_left = cputime_div(prof_left, nthreads);
1164 virt_left = cputime_sub(virt_expires, utime);
1165 virt_left = cputime_div(virt_left, nthreads);
1166 if (sched_expires) {
1167 sched_left = sched_expires - sched_time;
1168 do_div(sched_left, nthreads);
1169 } else {
1170 sched_left = 0;
1171 }
1172 t = tsk;
1173 do {
1174 ticks = cputime_add(cputime_add(t->utime, t->stime),
1175 prof_left);
1176 if (!cputime_eq(prof_expires, cputime_zero) &&
1177 (cputime_eq(t->it_prof_expires, cputime_zero) ||
1178 cputime_gt(t->it_prof_expires, ticks))) {
1179 t->it_prof_expires = ticks;
1180 }
1181
1182 ticks = cputime_add(t->utime, virt_left);
1183 if (!cputime_eq(virt_expires, cputime_zero) &&
1184 (cputime_eq(t->it_virt_expires, cputime_zero) ||
1185 cputime_gt(t->it_virt_expires, ticks))) {
1186 t->it_virt_expires = ticks;
1187 }
1188
1189 sched = t->sched_time + sched_left;
1190 if (sched_expires && (t->it_sched_expires == 0 ||
1191 t->it_sched_expires > sched)) {
1192 t->it_sched_expires = sched;
1193 }
1194
1195 do {
1196 t = next_thread(t);
1197 } while (unlikely(t->exit_state));
1198 } while (t != tsk);
1199 }
1200}
1201
1202/*
1203 * This is called from the signal code (via do_schedule_next_timer)
1204 * when the last timer signal was delivered and we have to reload the timer.
1205 */
1206void posix_cpu_timer_schedule(struct k_itimer *timer)
1207{
1208 struct task_struct *p = timer->it.cpu.task;
1209 union cpu_time_count now;
1210
1211 if (unlikely(p == NULL))
1212 /*
1213 * The task was cleaned up already, no future firings.
1214 */
1215 return;
1216
1217 /*
1218 * Fetch the current sample and update the timer's expiry time.
1219 */
1220 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1221 cpu_clock_sample(timer->it_clock, p, &now);
1222 bump_cpu_timer(timer, now);
1223 if (unlikely(p->exit_state)) {
1224 clear_dead_task(timer, now);
1225 return;
1226 }
1227 read_lock(&tasklist_lock); /* arm_timer needs it. */
1228 } else {
1229 read_lock(&tasklist_lock);
1230 if (unlikely(p->signal == NULL)) {
1231 /*
1232 * The process has been reaped.
1233 * We can't even collect a sample any more.
1234 */
1235 put_task_struct(p);
1236 timer->it.cpu.task = p = NULL;
1237 timer->it.cpu.expires.sched = 0;
1238 read_unlock(&tasklist_lock);
1239 return;
1240 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1241 /*
1242 * We've noticed that the thread is dead, but
1243 * not yet reaped. Take this opportunity to
1244 * drop our task ref.
1245 */
1246 clear_dead_task(timer, now);
1247 read_unlock(&tasklist_lock);
1248 return;
1249 }
1250 cpu_clock_sample_group(timer->it_clock, p, &now);
1251 bump_cpu_timer(timer, now);
1252 /* Leave the tasklist_lock locked for the call below. */
1253 }
1254
1255 /*
1256 * Now re-arm for the new expiry time.
1257 */
1258 arm_timer(timer, now);
1259
1260 read_unlock(&tasklist_lock);
1261}
1262
1263/*
1264 * This is called from the timer interrupt handler. The irq handler has
1265 * already updated our counts. We need to check if any timers fire now.
1266 * Interrupts are disabled.
1267 */
1268void run_posix_cpu_timers(struct task_struct *tsk)
1269{
1270 LIST_HEAD(firing);
1271 struct k_itimer *timer, *next;
1272
1273 BUG_ON(!irqs_disabled());
1274
1275#define UNEXPIRED(clock) \
1276 (cputime_eq(tsk->it_##clock##_expires, cputime_zero) || \
1277 cputime_lt(clock##_ticks(tsk), tsk->it_##clock##_expires))
1278
1279 if (UNEXPIRED(prof) && UNEXPIRED(virt) &&
1280 (tsk->it_sched_expires == 0 ||
1281 tsk->sched_time < tsk->it_sched_expires))
1282 return;
1283
1284#undef UNEXPIRED
1285
1286 BUG_ON(tsk->exit_state);
1287
1288 /*
1289 * Double-check with locks held.
1290 */
1291 read_lock(&tasklist_lock);
1292 spin_lock(&tsk->sighand->siglock);
1293
1294 /*
1295 * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
1296 * all the timers that are firing, and put them on the firing list.
1297 */
1298 check_thread_timers(tsk, &firing);
1299 check_process_timers(tsk, &firing);
1300
1301 /*
1302 * We must release these locks before taking any timer's lock.
1303 * There is a potential race with timer deletion here, as the
1304 * siglock now protects our private firing list. We have set
1305 * the firing flag in each timer, so that a deletion attempt
1306 * that gets the timer lock before we do will give it up and
1307 * spin until we've taken care of that timer below.
1308 */
1309 spin_unlock(&tsk->sighand->siglock);
1310 read_unlock(&tasklist_lock);
1311
1312 /*
1313 * Now that all the timers on our list have the firing flag,
1314 * noone will touch their list entries but us. We'll take
1315 * each timer's lock before clearing its firing flag, so no
1316 * timer call will interfere.
1317 */
1318 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1319 int firing;
1320 spin_lock(&timer->it_lock);
1321 list_del_init(&timer->it.cpu.entry);
1322 firing = timer->it.cpu.firing;
1323 timer->it.cpu.firing = 0;
1324 /*
1325 * The firing flag is -1 if we collided with a reset
1326 * of the timer, which already reported this
1327 * almost-firing as an overrun. So don't generate an event.
1328 */
1329 if (likely(firing >= 0)) {
1330 cpu_timer_fire(timer);
1331 }
1332 spin_unlock(&timer->it_lock);
1333 }
1334}
1335
1336/*
1337 * Set one of the process-wide special case CPU timers.
1338 * The tasklist_lock and tsk->sighand->siglock must be held by the caller.
1339 * The oldval argument is null for the RLIMIT_CPU timer, where *newval is
1340 * absolute; non-null for ITIMER_*, where *newval is relative and we update
1341 * it to be absolute, *oldval is absolute and we update it to be relative.
1342 */
1343void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1344 cputime_t *newval, cputime_t *oldval)
1345{
1346 union cpu_time_count now;
1347 struct list_head *head;
1348
1349 BUG_ON(clock_idx == CPUCLOCK_SCHED);
1350 cpu_clock_sample_group_locked(clock_idx, tsk, &now);
1351
1352 if (oldval) {
1353 if (!cputime_eq(*oldval, cputime_zero)) {
1354 if (cputime_le(*oldval, now.cpu)) {
1355 /* Just about to fire. */
1356 *oldval = jiffies_to_cputime(1);
1357 } else {
1358 *oldval = cputime_sub(*oldval, now.cpu);
1359 }
1360 }
1361
1362 if (cputime_eq(*newval, cputime_zero))
1363 return;
1364 *newval = cputime_add(*newval, now.cpu);
1365
1366 /*
1367 * If the RLIMIT_CPU timer will expire before the
1368 * ITIMER_PROF timer, we have nothing else to do.
1369 */
1370 if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
1371 < cputime_to_secs(*newval))
1372 return;
1373 }
1374
1375 /*
1376 * Check whether there are any process timers already set to fire
1377 * before this one. If so, we don't have anything more to do.
1378 */
1379 head = &tsk->signal->cpu_timers[clock_idx];
1380 if (list_empty(head) ||
1381 cputime_ge(list_entry(head->next,
1382 struct cpu_timer_list, entry)->expires.cpu,
1383 *newval)) {
1384 /*
1385 * Rejigger each thread's expiry time so that one will
1386 * notice before we hit the process-cumulative expiry time.
1387 */
1388 union cpu_time_count expires = { .sched = 0 };
1389 expires.cpu = *newval;
1390 process_timer_rebalance(tsk, clock_idx, expires, now);
1391 }
1392}
1393
1394static long posix_cpu_clock_nanosleep_restart(struct restart_block *);
1395
1396int posix_cpu_nsleep(clockid_t which_clock, int flags,
1397 struct timespec *rqtp)
1398{
1399 struct restart_block *restart_block =
1400 &current_thread_info()->restart_block;
1401 struct k_itimer timer;
1402 int error;
1403
1404 /*
1405 * Diagnose required errors first.
1406 */
1407 if (CPUCLOCK_PERTHREAD(which_clock) &&
1408 (CPUCLOCK_PID(which_clock) == 0 ||
1409 CPUCLOCK_PID(which_clock) == current->pid))
1410 return -EINVAL;
1411
1412 /*
1413 * Set up a temporary timer and then wait for it to go off.
1414 */
1415 memset(&timer, 0, sizeof timer);
1416 spin_lock_init(&timer.it_lock);
1417 timer.it_clock = which_clock;
1418 timer.it_overrun = -1;
1419 error = posix_cpu_timer_create(&timer);
1420 timer.it_process = current;
1421 if (!error) {
1422 struct timespec __user *rmtp;
1423 static struct itimerspec zero_it;
1424 struct itimerspec it = { .it_value = *rqtp,
1425 .it_interval = {} };
1426
1427 spin_lock_irq(&timer.it_lock);
1428 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1429 if (error) {
1430 spin_unlock_irq(&timer.it_lock);
1431 return error;
1432 }
1433
1434 while (!signal_pending(current)) {
1435 if (timer.it.cpu.expires.sched == 0) {
1436 /*
1437 * Our timer fired and was reset.
1438 */
1439 spin_unlock_irq(&timer.it_lock);
1440 return 0;
1441 }
1442
1443 /*
1444 * Block until cpu_timer_fire (or a signal) wakes us.
1445 */
1446 __set_current_state(TASK_INTERRUPTIBLE);
1447 spin_unlock_irq(&timer.it_lock);
1448 schedule();
1449 spin_lock_irq(&timer.it_lock);
1450 }
1451
1452 /*
1453 * We were interrupted by a signal.
1454 */
1455 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1456 posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1457 spin_unlock_irq(&timer.it_lock);
1458
1459 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1460 /*
1461 * It actually did fire already.
1462 */
1463 return 0;
1464 }
1465
1466 /*
1467 * Report back to the user the time still remaining.
1468 */
1469 rmtp = (struct timespec __user *) restart_block->arg1;
1470 if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
1471 copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1472 return -EFAULT;
1473
1474 restart_block->fn = posix_cpu_clock_nanosleep_restart;
1475 /* Caller already set restart_block->arg1 */
1476 restart_block->arg0 = which_clock;
1477 restart_block->arg2 = rqtp->tv_sec;
1478 restart_block->arg3 = rqtp->tv_nsec;
1479
1480 error = -ERESTART_RESTARTBLOCK;
1481 }
1482
1483 return error;
1484}
1485
1486static long
1487posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
1488{
1489 clockid_t which_clock = restart_block->arg0;
1490 struct timespec t = { .tv_sec = restart_block->arg2,
1491 .tv_nsec = restart_block->arg3 };
1492 restart_block->fn = do_no_restart_syscall;
1493 return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t);
1494}
1495
1496
1497#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1498#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1499
1500static int process_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
1501{
1502 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1503}
1504static int process_cpu_clock_get(clockid_t which_clock, struct timespec *tp)
1505{
1506 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1507}
1508static int process_cpu_timer_create(struct k_itimer *timer)
1509{
1510 timer->it_clock = PROCESS_CLOCK;
1511 return posix_cpu_timer_create(timer);
1512}
1513static int process_cpu_nsleep(clockid_t which_clock, int flags,
1514 struct timespec *rqtp)
1515{
1516 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1517}
1518static int thread_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
1519{
1520 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1521}
1522static int thread_cpu_clock_get(clockid_t which_clock, struct timespec *tp)
1523{
1524 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1525}
1526static int thread_cpu_timer_create(struct k_itimer *timer)
1527{
1528 timer->it_clock = THREAD_CLOCK;
1529 return posix_cpu_timer_create(timer);
1530}
1531static int thread_cpu_nsleep(clockid_t which_clock, int flags,
1532 struct timespec *rqtp)
1533{
1534 return -EINVAL;
1535}
1536
1537static __init int init_posix_cpu_timers(void)
1538{
1539 struct k_clock process = {
1540 .clock_getres = process_cpu_clock_getres,
1541 .clock_get = process_cpu_clock_get,
1542 .clock_set = do_posix_clock_nosettime,
1543 .timer_create = process_cpu_timer_create,
1544 .nsleep = process_cpu_nsleep,
1545 };
1546 struct k_clock thread = {
1547 .clock_getres = thread_cpu_clock_getres,
1548 .clock_get = thread_cpu_clock_get,
1549 .clock_set = do_posix_clock_nosettime,
1550 .timer_create = thread_cpu_timer_create,
1551 .nsleep = thread_cpu_nsleep,
1552 };
1553
1554 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1555 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1556
1557 return 0;
1558}
1559__initcall(init_posix_cpu_timers);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-26 17:41:25 -0500