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CommitLineData
1da177e4
LT
1/*
2 * Implement CPU time clocks for the POSIX clock interface.
3 */
4
5#include <linux/sched.h>
6#include <linux/posix-timers.h>
1da177e4 7#include <linux/errno.h>
f8bd2258
RZ
8#include <linux/math64.h>
9#include <asm/uaccess.h>
bb34d92f 10#include <linux/kernel_stat.h>
3f0a525e 11#include <trace/events/timer.h>
1da177e4 12
f06febc9 13/*
f55db609
SG
14 * Called after updating RLIMIT_CPU to run cpu timer and update
15 * tsk->signal->cputime_expires expiration cache if necessary. Needs
16 * siglock protection since other code may update expiration cache as
17 * well.
f06febc9
FM
18 */
19void update_rlimit_cpu(unsigned long rlim_new)
20{
42c4ab41 21 cputime_t cputime = secs_to_cputime(rlim_new);
f06febc9 22
f55db609
SG
23 spin_lock_irq(&current->sighand->siglock);
24 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
25 spin_unlock_irq(&current->sighand->siglock);
f06febc9
FM
26}
27
a924b04d 28static int check_clock(const clockid_t which_clock)
1da177e4
LT
29{
30 int error = 0;
31 struct task_struct *p;
32 const pid_t pid = CPUCLOCK_PID(which_clock);
33
34 if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
35 return -EINVAL;
36
37 if (pid == 0)
38 return 0;
39
40 read_lock(&tasklist_lock);
8dc86af0 41 p = find_task_by_vpid(pid);
bac0abd6
PE
42 if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
43 same_thread_group(p, current) : thread_group_leader(p))) {
1da177e4
LT
44 error = -EINVAL;
45 }
46 read_unlock(&tasklist_lock);
47
48 return error;
49}
50
51static inline union cpu_time_count
a924b04d 52timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
1da177e4
LT
53{
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) {
ee500f27 57 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
1da177e4
LT
58 } else {
59 ret.cpu = timespec_to_cputime(tp);
60 }
61 return ret;
62}
63
a924b04d 64static void sample_to_timespec(const clockid_t which_clock,
1da177e4
LT
65 union cpu_time_count cpu,
66 struct timespec *tp)
67{
f8bd2258
RZ
68 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
69 *tp = ns_to_timespec(cpu.sched);
70 else
1da177e4 71 cputime_to_timespec(cpu.cpu, tp);
1da177e4
LT
72}
73
a924b04d 74static inline int cpu_time_before(const clockid_t which_clock,
1da177e4
LT
75 union cpu_time_count now,
76 union cpu_time_count then)
77{
78 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
79 return now.sched < then.sched;
80 } else {
81 return cputime_lt(now.cpu, then.cpu);
82 }
83}
a924b04d 84static inline void cpu_time_add(const clockid_t which_clock,
1da177e4
LT
85 union cpu_time_count *acc,
86 union cpu_time_count val)
87{
88 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
89 acc->sched += val.sched;
90 } else {
91 acc->cpu = cputime_add(acc->cpu, val.cpu);
92 }
93}
a924b04d 94static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
1da177e4
LT
95 union cpu_time_count a,
96 union cpu_time_count b)
97{
98 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
99 a.sched -= b.sched;
100 } else {
101 a.cpu = cputime_sub(a.cpu, b.cpu);
102 }
103 return a;
104}
105
ac08c264
TG
106/*
107 * Divide and limit the result to res >= 1
108 *
109 * This is necessary to prevent signal delivery starvation, when the result of
110 * the division would be rounded down to 0.
111 */
112static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
113{
114 cputime_t res = cputime_div(time, div);
115
116 return max_t(cputime_t, res, 1);
117}
118
1da177e4
LT
119/*
120 * Update expiry time from increment, and increase overrun count,
121 * given the current clock sample.
122 */
7a4ed937 123static void bump_cpu_timer(struct k_itimer *timer,
1da177e4
LT
124 union cpu_time_count now)
125{
126 int i;
127
128 if (timer->it.cpu.incr.sched == 0)
129 return;
130
131 if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
132 unsigned long long delta, incr;
133
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--) {
7a4ed937 142 if (delta < incr)
1da177e4
LT
143 continue;
144 timer->it.cpu.expires.sched += incr;
145 timer->it_overrun += 1 << i;
146 delta -= incr;
147 }
148 } else {
149 cputime_t delta, incr;
150
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--) {
7a4ed937 160 if (cputime_lt(delta, incr))
1da177e4
LT
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);
166 }
167 }
168}
169
170static inline cputime_t prof_ticks(struct task_struct *p)
171{
172 return cputime_add(p->utime, p->stime);
173}
174static inline cputime_t virt_ticks(struct task_struct *p)
175{
176 return p->utime;
177}
1da177e4 178
a924b04d 179int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
1da177e4
LT
180{
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) {
186 /*
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.
190 */
191 tp->tv_nsec = 1;
192 }
193 }
194 return error;
195}
196
a924b04d 197int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
1da177e4
LT
198{
199 /*
200 * You can never reset a CPU clock, but we check for other errors
201 * in the call before failing with EPERM.
202 */
203 int error = check_clock(which_clock);
204 if (error == 0) {
205 error = -EPERM;
206 }
207 return error;
208}
209
210
211/*
212 * Sample a per-thread clock for the given task.
213 */
a924b04d 214static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
1da177e4
LT
215 union cpu_time_count *cpu)
216{
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:
c5f8d995 227 cpu->sched = task_sched_runtime(p);
1da177e4
LT
228 break;
229 }
230 return 0;
231}
232
4cd4c1b4
PZ
233void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
234{
235 struct sighand_struct *sighand;
236 struct signal_struct *sig;
237 struct task_struct *t;
238
239 *times = INIT_CPUTIME;
240
241 rcu_read_lock();
242 sighand = rcu_dereference(tsk->sighand);
243 if (!sighand)
244 goto out;
245
246 sig = tsk->signal;
247
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;
253
254 t = next_thread(t);
255 } while (t != tsk);
256
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;
260out:
261 rcu_read_unlock();
262}
263
4da94d49
PZ
264static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
265{
266 if (cputime_gt(b->utime, a->utime))
267 a->utime = b->utime;
268
269 if (cputime_gt(b->stime, a->stime))
270 a->stime = b->stime;
271
272 if (b->sum_exec_runtime > a->sum_exec_runtime)
273 a->sum_exec_runtime = b->sum_exec_runtime;
274}
275
276void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
277{
278 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
279 struct task_cputime sum;
280 unsigned long flags;
281
282 spin_lock_irqsave(&cputimer->lock, flags);
283 if (!cputimer->running) {
284 cputimer->running = 1;
285 /*
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.
290 */
291 thread_group_cputime(tsk, &sum);
292 update_gt_cputime(&cputimer->cputime, &sum);
293 }
294 *times = cputimer->cputime;
295 spin_unlock_irqrestore(&cputimer->lock, flags);
296}
297
1da177e4
LT
298/*
299 * Sample a process (thread group) clock for the given group_leader task.
300 * Must be called with tasklist_lock held for reading.
1da177e4 301 */
bb34d92f
FM
302static int cpu_clock_sample_group(const clockid_t which_clock,
303 struct task_struct *p,
304 union cpu_time_count *cpu)
1da177e4 305{
f06febc9
FM
306 struct task_cputime cputime;
307
eccdaeaf 308 switch (CPUCLOCK_WHICH(which_clock)) {
1da177e4
LT
309 default:
310 return -EINVAL;
311 case CPUCLOCK_PROF:
c5f8d995 312 thread_group_cputime(p, &cputime);
f06febc9 313 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
1da177e4
LT
314 break;
315 case CPUCLOCK_VIRT:
c5f8d995 316 thread_group_cputime(p, &cputime);
f06febc9 317 cpu->cpu = cputime.utime;
1da177e4
LT
318 break;
319 case CPUCLOCK_SCHED:
c5f8d995 320 cpu->sched = thread_group_sched_runtime(p);
1da177e4
LT
321 break;
322 }
323 return 0;
324}
325
1da177e4 326
a924b04d 327int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
1da177e4
LT
328{
329 const pid_t pid = CPUCLOCK_PID(which_clock);
330 int error = -EINVAL;
331 union cpu_time_count rtn;
332
333 if (pid == 0) {
334 /*
335 * Special case constant value for our own clocks.
336 * We don't have to do any lookup to find ourselves.
337 */
338 if (CPUCLOCK_PERTHREAD(which_clock)) {
339 /*
340 * Sampling just ourselves we can do with no locking.
341 */
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);
349 }
350 } else {
351 /*
352 * Find the given PID, and validate that the caller
353 * should be able to see it.
354 */
355 struct task_struct *p;
1f2ea083 356 rcu_read_lock();
8dc86af0 357 p = find_task_by_vpid(pid);
1da177e4
LT
358 if (p) {
359 if (CPUCLOCK_PERTHREAD(which_clock)) {
bac0abd6 360 if (same_thread_group(p, current)) {
1da177e4
LT
361 error = cpu_clock_sample(which_clock,
362 p, &rtn);
363 }
1f2ea083
PM
364 } else {
365 read_lock(&tasklist_lock);
d30fda35 366 if (thread_group_leader(p) && p->sighand) {
1f2ea083
PM
367 error =
368 cpu_clock_sample_group(which_clock,
369 p, &rtn);
370 }
371 read_unlock(&tasklist_lock);
1da177e4
LT
372 }
373 }
1f2ea083 374 rcu_read_unlock();
1da177e4
LT
375 }
376
377 if (error)
378 return error;
379 sample_to_timespec(which_clock, rtn, tp);
380 return 0;
381}
382
383
384/*
385 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
ba5ea951
SG
386 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
387 * new timer already all-zeros initialized.
1da177e4
LT
388 */
389int posix_cpu_timer_create(struct k_itimer *new_timer)
390{
391 int ret = 0;
392 const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
393 struct task_struct *p;
394
395 if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
396 return -EINVAL;
397
398 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
1da177e4
LT
399
400 read_lock(&tasklist_lock);
401 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
402 if (pid == 0) {
403 p = current;
404 } else {
8dc86af0 405 p = find_task_by_vpid(pid);
bac0abd6 406 if (p && !same_thread_group(p, current))
1da177e4
LT
407 p = NULL;
408 }
409 } else {
410 if (pid == 0) {
411 p = current->group_leader;
412 } else {
8dc86af0 413 p = find_task_by_vpid(pid);
bac0abd6 414 if (p && !thread_group_leader(p))
1da177e4
LT
415 p = NULL;
416 }
417 }
418 new_timer->it.cpu.task = p;
419 if (p) {
420 get_task_struct(p);
421 } else {
422 ret = -EINVAL;
423 }
424 read_unlock(&tasklist_lock);
425
426 return ret;
427}
428
429/*
430 * Clean up a CPU-clock timer that is about to be destroyed.
431 * This is called from timer deletion with the timer already locked.
432 * If we return TIMER_RETRY, it's necessary to release the timer's lock
433 * and try again. (This happens when the timer is in the middle of firing.)
434 */
435int posix_cpu_timer_del(struct k_itimer *timer)
436{
437 struct task_struct *p = timer->it.cpu.task;
108150ea 438 int ret = 0;
1da177e4 439
108150ea 440 if (likely(p != NULL)) {
9465bee8 441 read_lock(&tasklist_lock);
d30fda35 442 if (unlikely(p->sighand == NULL)) {
9465bee8
LT
443 /*
444 * We raced with the reaping of the task.
445 * The deletion should have cleared us off the list.
446 */
447 BUG_ON(!list_empty(&timer->it.cpu.entry));
448 } else {
9465bee8 449 spin_lock(&p->sighand->siglock);
108150ea
ON
450 if (timer->it.cpu.firing)
451 ret = TIMER_RETRY;
452 else
453 list_del(&timer->it.cpu.entry);
9465bee8
LT
454 spin_unlock(&p->sighand->siglock);
455 }
456 read_unlock(&tasklist_lock);
108150ea
ON
457
458 if (!ret)
459 put_task_struct(p);
1da177e4 460 }
1da177e4 461
108150ea 462 return ret;
1da177e4
LT
463}
464
465/*
466 * Clean out CPU timers still ticking when a thread exited. The task
467 * pointer is cleared, and the expiry time is replaced with the residual
468 * time for later timer_gettime calls to return.
469 * This must be called with the siglock held.
470 */
471static void cleanup_timers(struct list_head *head,
472 cputime_t utime, cputime_t stime,
41b86e9c 473 unsigned long long sum_exec_runtime)
1da177e4
LT
474{
475 struct cpu_timer_list *timer, *next;
476 cputime_t ptime = cputime_add(utime, stime);
477
478 list_for_each_entry_safe(timer, next, head, entry) {
1da177e4
LT
479 list_del_init(&timer->entry);
480 if (cputime_lt(timer->expires.cpu, ptime)) {
481 timer->expires.cpu = cputime_zero;
482 } else {
483 timer->expires.cpu = cputime_sub(timer->expires.cpu,
484 ptime);
485 }
486 }
487
488 ++head;
489 list_for_each_entry_safe(timer, next, head, entry) {
1da177e4
LT
490 list_del_init(&timer->entry);
491 if (cputime_lt(timer->expires.cpu, utime)) {
492 timer->expires.cpu = cputime_zero;
493 } else {
494 timer->expires.cpu = cputime_sub(timer->expires.cpu,
495 utime);
496 }
497 }
498
499 ++head;
500 list_for_each_entry_safe(timer, next, head, entry) {
1da177e4 501 list_del_init(&timer->entry);
41b86e9c 502 if (timer->expires.sched < sum_exec_runtime) {
1da177e4
LT
503 timer->expires.sched = 0;
504 } else {
41b86e9c 505 timer->expires.sched -= sum_exec_runtime;
1da177e4
LT
506 }
507 }
508}
509
510/*
511 * These are both called with the siglock held, when the current thread
512 * is being reaped. When the final (leader) thread in the group is reaped,
513 * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
514 */
515void posix_cpu_timers_exit(struct task_struct *tsk)
516{
517 cleanup_timers(tsk->cpu_timers,
41b86e9c 518 tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
1da177e4
LT
519
520}
521void posix_cpu_timers_exit_group(struct task_struct *tsk)
522{
17d42c1c 523 struct signal_struct *const sig = tsk->signal;
ca531a0a 524
f06febc9 525 cleanup_timers(tsk->signal->cpu_timers,
17d42c1c
SG
526 cputime_add(tsk->utime, sig->utime),
527 cputime_add(tsk->stime, sig->stime),
528 tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
1da177e4
LT
529}
530
531static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
532{
533 /*
534 * That's all for this thread or process.
535 * We leave our residual in expires to be reported.
536 */
537 put_task_struct(timer->it.cpu.task);
538 timer->it.cpu.task = NULL;
539 timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
540 timer->it.cpu.expires,
541 now);
542}
543
d1e3b6d1
SG
544static inline int expires_gt(cputime_t expires, cputime_t new_exp)
545{
546 return cputime_eq(expires, cputime_zero) ||
547 cputime_gt(expires, new_exp);
548}
549
1da177e4
LT
550/*
551 * Insert the timer on the appropriate list before any timers that
552 * expire later. This must be called with the tasklist_lock held
c2873937 553 * for reading, interrupts disabled and p->sighand->siglock taken.
1da177e4 554 */
5eb9aa64 555static void arm_timer(struct k_itimer *timer)
1da177e4
LT
556{
557 struct task_struct *p = timer->it.cpu.task;
558 struct list_head *head, *listpos;
5eb9aa64 559 struct task_cputime *cputime_expires;
1da177e4
LT
560 struct cpu_timer_list *const nt = &timer->it.cpu;
561 struct cpu_timer_list *next;
1da177e4 562
5eb9aa64
SG
563 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
564 head = p->cpu_timers;
565 cputime_expires = &p->cputime_expires;
566 } else {
567 head = p->signal->cpu_timers;
568 cputime_expires = &p->signal->cputime_expires;
569 }
1da177e4
LT
570 head += CPUCLOCK_WHICH(timer->it_clock);
571
1da177e4 572 listpos = head;
5eb9aa64
SG
573 list_for_each_entry(next, head, entry) {
574 if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
575 break;
576 listpos = &next->entry;
1da177e4
LT
577 }
578 list_add(&nt->entry, listpos);
579
580 if (listpos == head) {
5eb9aa64
SG
581 union cpu_time_count *exp = &nt->expires;
582
1da177e4 583 /*
5eb9aa64
SG
584 * We are the new earliest-expiring POSIX 1.b timer, hence
585 * need to update expiration cache. Take into account that
586 * for process timers we share expiration cache with itimers
587 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
1da177e4
LT
588 */
589
5eb9aa64
SG
590 switch (CPUCLOCK_WHICH(timer->it_clock)) {
591 case CPUCLOCK_PROF:
592 if (expires_gt(cputime_expires->prof_exp, exp->cpu))
593 cputime_expires->prof_exp = exp->cpu;
594 break;
595 case CPUCLOCK_VIRT:
596 if (expires_gt(cputime_expires->virt_exp, exp->cpu))
597 cputime_expires->virt_exp = exp->cpu;
598 break;
599 case CPUCLOCK_SCHED:
600 if (cputime_expires->sched_exp == 0 ||
601 cputime_expires->sched_exp > exp->sched)
602 cputime_expires->sched_exp = exp->sched;
603 break;
1da177e4
LT
604 }
605 }
1da177e4
LT
606}
607
608/*
609 * The timer is locked, fire it and arrange for its reload.
610 */
611static void cpu_timer_fire(struct k_itimer *timer)
612{
1f169f84
SG
613 if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
614 /*
615 * User don't want any signal.
616 */
617 timer->it.cpu.expires.sched = 0;
618 } else if (unlikely(timer->sigq == NULL)) {
1da177e4
LT
619 /*
620 * This a special case for clock_nanosleep,
621 * not a normal timer from sys_timer_create.
622 */
623 wake_up_process(timer->it_process);
624 timer->it.cpu.expires.sched = 0;
625 } else if (timer->it.cpu.incr.sched == 0) {
626 /*
627 * One-shot timer. Clear it as soon as it's fired.
628 */
629 posix_timer_event(timer, 0);
630 timer->it.cpu.expires.sched = 0;
631 } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
632 /*
633 * The signal did not get queued because the signal
634 * was ignored, so we won't get any callback to
635 * reload the timer. But we need to keep it
636 * ticking in case the signal is deliverable next time.
637 */
638 posix_cpu_timer_schedule(timer);
639 }
640}
641
3997ad31
PZ
642/*
643 * Sample a process (thread group) timer for the given group_leader task.
644 * Must be called with tasklist_lock held for reading.
645 */
646static int cpu_timer_sample_group(const clockid_t which_clock,
647 struct task_struct *p,
648 union cpu_time_count *cpu)
649{
650 struct task_cputime cputime;
651
652 thread_group_cputimer(p, &cputime);
653 switch (CPUCLOCK_WHICH(which_clock)) {
654 default:
655 return -EINVAL;
656 case CPUCLOCK_PROF:
657 cpu->cpu = cputime_add(cputime.utime, cputime.stime);
658 break;
659 case CPUCLOCK_VIRT:
660 cpu->cpu = cputime.utime;
661 break;
662 case CPUCLOCK_SCHED:
663 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
664 break;
665 }
666 return 0;
667}
668
1da177e4
LT
669/*
670 * Guts of sys_timer_settime for CPU timers.
671 * This is called with the timer locked and interrupts disabled.
672 * If we return TIMER_RETRY, it's necessary to release the timer's lock
673 * and try again. (This happens when the timer is in the middle of firing.)
674 */
675int posix_cpu_timer_set(struct k_itimer *timer, int flags,
676 struct itimerspec *new, struct itimerspec *old)
677{
678 struct task_struct *p = timer->it.cpu.task;
ae1a78ee 679 union cpu_time_count old_expires, new_expires, old_incr, val;
1da177e4
LT
680 int ret;
681
682 if (unlikely(p == NULL)) {
683 /*
684 * Timer refers to a dead task's clock.
685 */
686 return -ESRCH;
687 }
688
689 new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
690
691 read_lock(&tasklist_lock);
692 /*
693 * We need the tasklist_lock to protect against reaping that
d30fda35 694 * clears p->sighand. If p has just been reaped, we can no
1da177e4
LT
695 * longer get any information about it at all.
696 */
d30fda35 697 if (unlikely(p->sighand == NULL)) {
1da177e4
LT
698 read_unlock(&tasklist_lock);
699 put_task_struct(p);
700 timer->it.cpu.task = NULL;
701 return -ESRCH;
702 }
703
704 /*
705 * Disarm any old timer after extracting its expiry time.
706 */
707 BUG_ON(!irqs_disabled());
a69ac4a7
ON
708
709 ret = 0;
ae1a78ee 710 old_incr = timer->it.cpu.incr;
1da177e4
LT
711 spin_lock(&p->sighand->siglock);
712 old_expires = timer->it.cpu.expires;
a69ac4a7
ON
713 if (unlikely(timer->it.cpu.firing)) {
714 timer->it.cpu.firing = -1;
715 ret = TIMER_RETRY;
716 } else
717 list_del_init(&timer->it.cpu.entry);
1da177e4
LT
718
719 /*
720 * We need to sample the current value to convert the new
721 * value from to relative and absolute, and to convert the
722 * old value from absolute to relative. To set a process
723 * timer, we need a sample to balance the thread expiry
724 * times (in arm_timer). With an absolute time, we must
725 * check if it's already passed. In short, we need a sample.
726 */
727 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
728 cpu_clock_sample(timer->it_clock, p, &val);
729 } else {
3997ad31 730 cpu_timer_sample_group(timer->it_clock, p, &val);
1da177e4
LT
731 }
732
733 if (old) {
734 if (old_expires.sched == 0) {
735 old->it_value.tv_sec = 0;
736 old->it_value.tv_nsec = 0;
737 } else {
738 /*
739 * Update the timer in case it has
740 * overrun already. If it has,
741 * we'll report it as having overrun
742 * and with the next reloaded timer
743 * already ticking, though we are
744 * swallowing that pending
745 * notification here to install the
746 * new setting.
747 */
748 bump_cpu_timer(timer, val);
749 if (cpu_time_before(timer->it_clock, val,
750 timer->it.cpu.expires)) {
751 old_expires = cpu_time_sub(
752 timer->it_clock,
753 timer->it.cpu.expires, val);
754 sample_to_timespec(timer->it_clock,
755 old_expires,
756 &old->it_value);
757 } else {
758 old->it_value.tv_nsec = 1;
759 old->it_value.tv_sec = 0;
760 }
761 }
762 }
763
a69ac4a7 764 if (unlikely(ret)) {
1da177e4
LT
765 /*
766 * We are colliding with the timer actually firing.
767 * Punt after filling in the timer's old value, and
768 * disable this firing since we are already reporting
769 * it as an overrun (thanks to bump_cpu_timer above).
770 */
c2873937 771 spin_unlock(&p->sighand->siglock);
1da177e4 772 read_unlock(&tasklist_lock);
1da177e4
LT
773 goto out;
774 }
775
776 if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
777 cpu_time_add(timer->it_clock, &new_expires, val);
778 }
779
780 /*
781 * Install the new expiry time (or zero).
782 * For a timer with no notification action, we don't actually
783 * arm the timer (we'll just fake it for timer_gettime).
784 */
785 timer->it.cpu.expires = new_expires;
786 if (new_expires.sched != 0 &&
1da177e4 787 cpu_time_before(timer->it_clock, val, new_expires)) {
5eb9aa64 788 arm_timer(timer);
1da177e4
LT
789 }
790
c2873937 791 spin_unlock(&p->sighand->siglock);
1da177e4
LT
792 read_unlock(&tasklist_lock);
793
794 /*
795 * Install the new reload setting, and
796 * set up the signal and overrun bookkeeping.
797 */
798 timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
799 &new->it_interval);
800
801 /*
802 * This acts as a modification timestamp for the timer,
803 * so any automatic reload attempt will punt on seeing
804 * that we have reset the timer manually.
805 */
806 timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
807 ~REQUEUE_PENDING;
808 timer->it_overrun_last = 0;
809 timer->it_overrun = -1;
810
811 if (new_expires.sched != 0 &&
1da177e4
LT
812 !cpu_time_before(timer->it_clock, val, new_expires)) {
813 /*
814 * The designated time already passed, so we notify
815 * immediately, even if the thread never runs to
816 * accumulate more time on this clock.
817 */
818 cpu_timer_fire(timer);
819 }
820
821 ret = 0;
822 out:
823 if (old) {
824 sample_to_timespec(timer->it_clock,
ae1a78ee 825 old_incr, &old->it_interval);
1da177e4
LT
826 }
827 return ret;
828}
829
830void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
831{
832 union cpu_time_count now;
833 struct task_struct *p = timer->it.cpu.task;
834 int clear_dead;
835
836 /*
837 * Easy part: convert the reload time.
838 */
839 sample_to_timespec(timer->it_clock,
840 timer->it.cpu.incr, &itp->it_interval);
841
842 if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
843 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
844 return;
845 }
846
847 if (unlikely(p == NULL)) {
848 /*
849 * This task already died and the timer will never fire.
850 * In this case, expires is actually the dead value.
851 */
852 dead:
853 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
854 &itp->it_value);
855 return;
856 }
857
858 /*
859 * Sample the clock to take the difference with the expiry time.
860 */
861 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
862 cpu_clock_sample(timer->it_clock, p, &now);
863 clear_dead = p->exit_state;
864 } else {
865 read_lock(&tasklist_lock);
d30fda35 866 if (unlikely(p->sighand == NULL)) {
1da177e4
LT
867 /*
868 * The process has been reaped.
869 * We can't even collect a sample any more.
870 * Call the timer disarmed, nothing else to do.
871 */
872 put_task_struct(p);
873 timer->it.cpu.task = NULL;
874 timer->it.cpu.expires.sched = 0;
875 read_unlock(&tasklist_lock);
876 goto dead;
877 } else {
3997ad31 878 cpu_timer_sample_group(timer->it_clock, p, &now);
1da177e4
LT
879 clear_dead = (unlikely(p->exit_state) &&
880 thread_group_empty(p));
881 }
882 read_unlock(&tasklist_lock);
883 }
884
1da177e4
LT
885 if (unlikely(clear_dead)) {
886 /*
887 * We've noticed that the thread is dead, but
888 * not yet reaped. Take this opportunity to
889 * drop our task ref.
890 */
891 clear_dead_task(timer, now);
892 goto dead;
893 }
894
895 if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
896 sample_to_timespec(timer->it_clock,
897 cpu_time_sub(timer->it_clock,
898 timer->it.cpu.expires, now),
899 &itp->it_value);
900 } else {
901 /*
902 * The timer should have expired already, but the firing
903 * hasn't taken place yet. Say it's just about to expire.
904 */
905 itp->it_value.tv_nsec = 1;
906 itp->it_value.tv_sec = 0;
907 }
908}
909
910/*
911 * Check for any per-thread CPU timers that have fired and move them off
912 * the tsk->cpu_timers[N] list onto the firing list. Here we update the
913 * tsk->it_*_expires values to reflect the remaining thread CPU timers.
914 */
915static void check_thread_timers(struct task_struct *tsk,
916 struct list_head *firing)
917{
e80eda94 918 int maxfire;
1da177e4 919 struct list_head *timers = tsk->cpu_timers;
78f2c7db 920 struct signal_struct *const sig = tsk->signal;
d4bb5274 921 unsigned long soft;
1da177e4 922
e80eda94 923 maxfire = 20;
f06febc9 924 tsk->cputime_expires.prof_exp = cputime_zero;
1da177e4 925 while (!list_empty(timers)) {
b5e61818 926 struct cpu_timer_list *t = list_first_entry(timers,
1da177e4
LT
927 struct cpu_timer_list,
928 entry);
e80eda94 929 if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
f06febc9 930 tsk->cputime_expires.prof_exp = t->expires.cpu;
1da177e4
LT
931 break;
932 }
933 t->firing = 1;
934 list_move_tail(&t->entry, firing);
935 }
936
937 ++timers;
e80eda94 938 maxfire = 20;
f06febc9 939 tsk->cputime_expires.virt_exp = cputime_zero;
1da177e4 940 while (!list_empty(timers)) {
b5e61818 941 struct cpu_timer_list *t = list_first_entry(timers,
1da177e4
LT
942 struct cpu_timer_list,
943 entry);
e80eda94 944 if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
f06febc9 945 tsk->cputime_expires.virt_exp = t->expires.cpu;
1da177e4
LT
946 break;
947 }
948 t->firing = 1;
949 list_move_tail(&t->entry, firing);
950 }
951
952 ++timers;
e80eda94 953 maxfire = 20;
f06febc9 954 tsk->cputime_expires.sched_exp = 0;
1da177e4 955 while (!list_empty(timers)) {
b5e61818 956 struct cpu_timer_list *t = list_first_entry(timers,
1da177e4
LT
957 struct cpu_timer_list,
958 entry);
41b86e9c 959 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
f06febc9 960 tsk->cputime_expires.sched_exp = t->expires.sched;
1da177e4
LT
961 break;
962 }
963 t->firing = 1;
964 list_move_tail(&t->entry, firing);
965 }
78f2c7db
PZ
966
967 /*
968 * Check for the special case thread timers.
969 */
78d7d407 970 soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
d4bb5274 971 if (soft != RLIM_INFINITY) {
78d7d407
JS
972 unsigned long hard =
973 ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
78f2c7db 974
5a52dd50
PZ
975 if (hard != RLIM_INFINITY &&
976 tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
78f2c7db
PZ
977 /*
978 * At the hard limit, we just die.
979 * No need to calculate anything else now.
980 */
981 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
982 return;
983 }
d4bb5274 984 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
78f2c7db
PZ
985 /*
986 * At the soft limit, send a SIGXCPU every second.
987 */
d4bb5274
JS
988 if (soft < hard) {
989 soft += USEC_PER_SEC;
990 sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
78f2c7db 991 }
81d50bb2
HS
992 printk(KERN_INFO
993 "RT Watchdog Timeout: %s[%d]\n",
994 tsk->comm, task_pid_nr(tsk));
78f2c7db
PZ
995 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
996 }
997 }
1da177e4
LT
998}
999
15365c10 1000static void stop_process_timers(struct signal_struct *sig)
3fccfd67 1001{
15365c10 1002 struct thread_group_cputimer *cputimer = &sig->cputimer;
3fccfd67
PZ
1003 unsigned long flags;
1004
3fccfd67
PZ
1005 spin_lock_irqsave(&cputimer->lock, flags);
1006 cputimer->running = 0;
1007 spin_unlock_irqrestore(&cputimer->lock, flags);
1008}
1009
8356b5f9
SG
1010static u32 onecputick;
1011
42c4ab41
SG
1012static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
1013 cputime_t *expires, cputime_t cur_time, int signo)
1014{
1015 if (cputime_eq(it->expires, cputime_zero))
1016 return;
1017
1018 if (cputime_ge(cur_time, it->expires)) {
8356b5f9
SG
1019 if (!cputime_eq(it->incr, cputime_zero)) {
1020 it->expires = cputime_add(it->expires, it->incr);
1021 it->error += it->incr_error;
1022 if (it->error >= onecputick) {
1023 it->expires = cputime_sub(it->expires,
a42548a1 1024 cputime_one_jiffy);
8356b5f9
SG
1025 it->error -= onecputick;
1026 }
3f0a525e 1027 } else {
8356b5f9 1028 it->expires = cputime_zero;
3f0a525e 1029 }
42c4ab41 1030
3f0a525e
XG
1031 trace_itimer_expire(signo == SIGPROF ?
1032 ITIMER_PROF : ITIMER_VIRTUAL,
1033 tsk->signal->leader_pid, cur_time);
42c4ab41
SG
1034 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
1035 }
1036
1037 if (!cputime_eq(it->expires, cputime_zero) &&
1038 (cputime_eq(*expires, cputime_zero) ||
1039 cputime_lt(it->expires, *expires))) {
1040 *expires = it->expires;
1041 }
1042}
1043
29f87b79
SG
1044/**
1045 * task_cputime_zero - Check a task_cputime struct for all zero fields.
1046 *
1047 * @cputime: The struct to compare.
1048 *
1049 * Checks @cputime to see if all fields are zero. Returns true if all fields
1050 * are zero, false if any field is nonzero.
1051 */
1052static inline int task_cputime_zero(const struct task_cputime *cputime)
1053{
1054 if (cputime_eq(cputime->utime, cputime_zero) &&
1055 cputime_eq(cputime->stime, cputime_zero) &&
1056 cputime->sum_exec_runtime == 0)
1057 return 1;
1058 return 0;
1059}
1060
1da177e4
LT
1061/*
1062 * Check for any per-thread CPU timers that have fired and move them
1063 * off the tsk->*_timers list onto the firing list. Per-thread timers
1064 * have already been taken off.
1065 */
1066static void check_process_timers(struct task_struct *tsk,
1067 struct list_head *firing)
1068{
e80eda94 1069 int maxfire;
1da177e4 1070 struct signal_struct *const sig = tsk->signal;
f06febc9 1071 cputime_t utime, ptime, virt_expires, prof_expires;
41b86e9c 1072 unsigned long long sum_sched_runtime, sched_expires;
1da177e4 1073 struct list_head *timers = sig->cpu_timers;
f06febc9 1074 struct task_cputime cputime;
d4bb5274 1075 unsigned long soft;
1da177e4 1076
1da177e4
LT
1077 /*
1078 * Collect the current process totals.
1079 */
4cd4c1b4 1080 thread_group_cputimer(tsk, &cputime);
f06febc9
FM
1081 utime = cputime.utime;
1082 ptime = cputime_add(utime, cputime.stime);
1083 sum_sched_runtime = cputime.sum_exec_runtime;
e80eda94 1084 maxfire = 20;
1da177e4
LT
1085 prof_expires = cputime_zero;
1086 while (!list_empty(timers)) {
ee7dd205 1087 struct cpu_timer_list *tl = list_first_entry(timers,
1da177e4
LT
1088 struct cpu_timer_list,
1089 entry);
ee7dd205
WC
1090 if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
1091 prof_expires = tl->expires.cpu;
1da177e4
LT
1092 break;
1093 }
ee7dd205
WC
1094 tl->firing = 1;
1095 list_move_tail(&tl->entry, firing);
1da177e4
LT
1096 }
1097
1098 ++timers;
e80eda94 1099 maxfire = 20;
1da177e4
LT
1100 virt_expires = cputime_zero;
1101 while (!list_empty(timers)) {
ee7dd205 1102 struct cpu_timer_list *tl = list_first_entry(timers,
1da177e4
LT
1103 struct cpu_timer_list,
1104 entry);
ee7dd205
WC
1105 if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
1106 virt_expires = tl->expires.cpu;
1da177e4
LT
1107 break;
1108 }
ee7dd205
WC
1109 tl->firing = 1;
1110 list_move_tail(&tl->entry, firing);
1da177e4
LT
1111 }
1112
1113 ++timers;
e80eda94 1114 maxfire = 20;
1da177e4
LT
1115 sched_expires = 0;
1116 while (!list_empty(timers)) {
ee7dd205 1117 struct cpu_timer_list *tl = list_first_entry(timers,
1da177e4
LT
1118 struct cpu_timer_list,
1119 entry);
ee7dd205
WC
1120 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1121 sched_expires = tl->expires.sched;
1da177e4
LT
1122 break;
1123 }
ee7dd205
WC
1124 tl->firing = 1;
1125 list_move_tail(&tl->entry, firing);
1da177e4
LT
1126 }
1127
1128 /*
1129 * Check for the special case process timers.
1130 */
42c4ab41
SG
1131 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
1132 SIGPROF);
1133 check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
1134 SIGVTALRM);
78d7d407 1135 soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
d4bb5274 1136 if (soft != RLIM_INFINITY) {
1da177e4 1137 unsigned long psecs = cputime_to_secs(ptime);
78d7d407
JS
1138 unsigned long hard =
1139 ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
1da177e4 1140 cputime_t x;
d4bb5274 1141 if (psecs >= hard) {
1da177e4
LT
1142 /*
1143 * At the hard limit, we just die.
1144 * No need to calculate anything else now.
1145 */
1146 __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1147 return;
1148 }
d4bb5274 1149 if (psecs >= soft) {
1da177e4
LT
1150 /*
1151 * At the soft limit, send a SIGXCPU every second.
1152 */
1153 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
d4bb5274
JS
1154 if (soft < hard) {
1155 soft++;
1156 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
1da177e4
LT
1157 }
1158 }
d4bb5274 1159 x = secs_to_cputime(soft);
1da177e4
LT
1160 if (cputime_eq(prof_expires, cputime_zero) ||
1161 cputime_lt(x, prof_expires)) {
1162 prof_expires = x;
1163 }
1164 }
1165
29f87b79
SG
1166 sig->cputime_expires.prof_exp = prof_expires;
1167 sig->cputime_expires.virt_exp = virt_expires;
1168 sig->cputime_expires.sched_exp = sched_expires;
1169 if (task_cputime_zero(&sig->cputime_expires))
1170 stop_process_timers(sig);
1da177e4
LT
1171}
1172
1173/*
1174 * This is called from the signal code (via do_schedule_next_timer)
1175 * when the last timer signal was delivered and we have to reload the timer.
1176 */
1177void posix_cpu_timer_schedule(struct k_itimer *timer)
1178{
1179 struct task_struct *p = timer->it.cpu.task;
1180 union cpu_time_count now;
1181
1182 if (unlikely(p == NULL))
1183 /*
1184 * The task was cleaned up already, no future firings.
1185 */
708f430d 1186 goto out;
1da177e4
LT
1187
1188 /*
1189 * Fetch the current sample and update the timer's expiry time.
1190 */
1191 if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1192 cpu_clock_sample(timer->it_clock, p, &now);
1193 bump_cpu_timer(timer, now);
1194 if (unlikely(p->exit_state)) {
1195 clear_dead_task(timer, now);
708f430d 1196 goto out;
1da177e4
LT
1197 }
1198 read_lock(&tasklist_lock); /* arm_timer needs it. */
c2873937 1199 spin_lock(&p->sighand->siglock);
1da177e4
LT
1200 } else {
1201 read_lock(&tasklist_lock);
d30fda35 1202 if (unlikely(p->sighand == NULL)) {
1da177e4
LT
1203 /*
1204 * The process has been reaped.
1205 * We can't even collect a sample any more.
1206 */
1207 put_task_struct(p);
1208 timer->it.cpu.task = p = NULL;
1209 timer->it.cpu.expires.sched = 0;
708f430d 1210 goto out_unlock;
1da177e4
LT
1211 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1212 /*
1213 * We've noticed that the thread is dead, but
1214 * not yet reaped. Take this opportunity to
1215 * drop our task ref.
1216 */
1217 clear_dead_task(timer, now);
708f430d 1218 goto out_unlock;
1da177e4 1219 }
c2873937 1220 spin_lock(&p->sighand->siglock);
3997ad31 1221 cpu_timer_sample_group(timer->it_clock, p, &now);
1da177e4
LT
1222 bump_cpu_timer(timer, now);
1223 /* Leave the tasklist_lock locked for the call below. */
1224 }
1225
1226 /*
1227 * Now re-arm for the new expiry time.
1228 */
c2873937 1229 BUG_ON(!irqs_disabled());
5eb9aa64 1230 arm_timer(timer);
c2873937 1231 spin_unlock(&p->sighand->siglock);
1da177e4 1232
708f430d 1233out_unlock:
1da177e4 1234 read_unlock(&tasklist_lock);
708f430d
RM
1235
1236out:
1237 timer->it_overrun_last = timer->it_overrun;
1238 timer->it_overrun = -1;
1239 ++timer->it_requeue_pending;
1da177e4
LT
1240}
1241
f06febc9
FM
1242/**
1243 * task_cputime_expired - Compare two task_cputime entities.
1244 *
1245 * @sample: The task_cputime structure to be checked for expiration.
1246 * @expires: Expiration times, against which @sample will be checked.
1247 *
1248 * Checks @sample against @expires to see if any field of @sample has expired.
1249 * Returns true if any field of the former is greater than the corresponding
1250 * field of the latter if the latter field is set. Otherwise returns false.
1251 */
1252static inline int task_cputime_expired(const struct task_cputime *sample,
1253 const struct task_cputime *expires)
1254{
1255 if (!cputime_eq(expires->utime, cputime_zero) &&
1256 cputime_ge(sample->utime, expires->utime))
1257 return 1;
1258 if (!cputime_eq(expires->stime, cputime_zero) &&
1259 cputime_ge(cputime_add(sample->utime, sample->stime),
1260 expires->stime))
1261 return 1;
1262 if (expires->sum_exec_runtime != 0 &&
1263 sample->sum_exec_runtime >= expires->sum_exec_runtime)
1264 return 1;
1265 return 0;
1266}
1267
1268/**
1269 * fastpath_timer_check - POSIX CPU timers fast path.
1270 *
1271 * @tsk: The task (thread) being checked.
f06febc9 1272 *
bb34d92f
FM
1273 * Check the task and thread group timers. If both are zero (there are no
1274 * timers set) return false. Otherwise snapshot the task and thread group
1275 * timers and compare them with the corresponding expiration times. Return
1276 * true if a timer has expired, else return false.
f06febc9 1277 */
bb34d92f 1278static inline int fastpath_timer_check(struct task_struct *tsk)
f06febc9 1279{
ad133ba3 1280 struct signal_struct *sig;
bb34d92f 1281
ad133ba3
ON
1282 /* tsk == current, ensure it is safe to use ->signal/sighand */
1283 if (unlikely(tsk->exit_state))
f06febc9 1284 return 0;
bb34d92f
FM
1285
1286 if (!task_cputime_zero(&tsk->cputime_expires)) {
1287 struct task_cputime task_sample = {
1288 .utime = tsk->utime,
1289 .stime = tsk->stime,
1290 .sum_exec_runtime = tsk->se.sum_exec_runtime
1291 };
1292
1293 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1294 return 1;
1295 }
ad133ba3
ON
1296
1297 sig = tsk->signal;
29f87b79 1298 if (sig->cputimer.running) {
bb34d92f
FM
1299 struct task_cputime group_sample;
1300
4cd4c1b4 1301 thread_group_cputimer(tsk, &group_sample);
bb34d92f
FM
1302 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1303 return 1;
1304 }
37bebc70 1305
f55db609 1306 return 0;
f06febc9
FM
1307}
1308
1da177e4
LT
1309/*
1310 * This is called from the timer interrupt handler. The irq handler has
1311 * already updated our counts. We need to check if any timers fire now.
1312 * Interrupts are disabled.
1313 */
1314void run_posix_cpu_timers(struct task_struct *tsk)
1315{
1316 LIST_HEAD(firing);
1317 struct k_itimer *timer, *next;
1318
1319 BUG_ON(!irqs_disabled());
1320
1da177e4 1321 /*
f06febc9 1322 * The fast path checks that there are no expired thread or thread
bb34d92f 1323 * group timers. If that's so, just return.
1da177e4 1324 */
bb34d92f 1325 if (!fastpath_timer_check(tsk))
f06febc9 1326 return;
5ce73a4a 1327
bb34d92f
FM
1328 spin_lock(&tsk->sighand->siglock);
1329 /*
1330 * Here we take off tsk->signal->cpu_timers[N] and
1331 * tsk->cpu_timers[N] all the timers that are firing, and
1332 * put them on the firing list.
1333 */
1334 check_thread_timers(tsk, &firing);
29f87b79
SG
1335 /*
1336 * If there are any active process wide timers (POSIX 1.b, itimers,
1337 * RLIMIT_CPU) cputimer must be running.
1338 */
1339 if (tsk->signal->cputimer.running)
1340 check_process_timers(tsk, &firing);
1da177e4 1341
bb34d92f
FM
1342 /*
1343 * We must release these locks before taking any timer's lock.
1344 * There is a potential race with timer deletion here, as the
1345 * siglock now protects our private firing list. We have set
1346 * the firing flag in each timer, so that a deletion attempt
1347 * that gets the timer lock before we do will give it up and
1348 * spin until we've taken care of that timer below.
1349 */
1350 spin_unlock(&tsk->sighand->siglock);
1da177e4
LT
1351
1352 /*
1353 * Now that all the timers on our list have the firing flag,
1354 * noone will touch their list entries but us. We'll take
1355 * each timer's lock before clearing its firing flag, so no
1356 * timer call will interfere.
1357 */
1358 list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
6e85c5ba
HS
1359 int cpu_firing;
1360
1da177e4
LT
1361 spin_lock(&timer->it_lock);
1362 list_del_init(&timer->it.cpu.entry);
6e85c5ba 1363 cpu_firing = timer->it.cpu.firing;
1da177e4
LT
1364 timer->it.cpu.firing = 0;
1365 /*
1366 * The firing flag is -1 if we collided with a reset
1367 * of the timer, which already reported this
1368 * almost-firing as an overrun. So don't generate an event.
1369 */
6e85c5ba 1370 if (likely(cpu_firing >= 0))
1da177e4 1371 cpu_timer_fire(timer);
1da177e4
LT
1372 spin_unlock(&timer->it_lock);
1373 }
1374}
1375
1376/*
f55db609 1377 * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
f06febc9 1378 * The tsk->sighand->siglock must be held by the caller.
1da177e4
LT
1379 */
1380void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1381 cputime_t *newval, cputime_t *oldval)
1382{
1383 union cpu_time_count now;
1da177e4
LT
1384
1385 BUG_ON(clock_idx == CPUCLOCK_SCHED);
4cd4c1b4 1386 cpu_timer_sample_group(clock_idx, tsk, &now);
1da177e4
LT
1387
1388 if (oldval) {
f55db609
SG
1389 /*
1390 * We are setting itimer. The *oldval is absolute and we update
1391 * it to be relative, *newval argument is relative and we update
1392 * it to be absolute.
1393 */
1da177e4
LT
1394 if (!cputime_eq(*oldval, cputime_zero)) {
1395 if (cputime_le(*oldval, now.cpu)) {
1396 /* Just about to fire. */
a42548a1 1397 *oldval = cputime_one_jiffy;
1da177e4
LT
1398 } else {
1399 *oldval = cputime_sub(*oldval, now.cpu);
1400 }
1401 }
1402
1403 if (cputime_eq(*newval, cputime_zero))
1404 return;
1405 *newval = cputime_add(*newval, now.cpu);
1da177e4
LT
1406 }
1407
1408 /*
f55db609
SG
1409 * Update expiration cache if we are the earliest timer, or eventually
1410 * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1da177e4 1411 */
f55db609
SG
1412 switch (clock_idx) {
1413 case CPUCLOCK_PROF:
1414 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
f06febc9 1415 tsk->signal->cputime_expires.prof_exp = *newval;
f55db609
SG
1416 break;
1417 case CPUCLOCK_VIRT:
1418 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
f06febc9 1419 tsk->signal->cputime_expires.virt_exp = *newval;
f55db609 1420 break;
1da177e4
LT
1421 }
1422}
1423
e4b76555
TA
1424static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1425 struct timespec *rqtp, struct itimerspec *it)
1da177e4 1426{
1da177e4
LT
1427 struct k_itimer timer;
1428 int error;
1429
1da177e4
LT
1430 /*
1431 * Set up a temporary timer and then wait for it to go off.
1432 */
1433 memset(&timer, 0, sizeof timer);
1434 spin_lock_init(&timer.it_lock);
1435 timer.it_clock = which_clock;
1436 timer.it_overrun = -1;
1437 error = posix_cpu_timer_create(&timer);
1438 timer.it_process = current;
1439 if (!error) {
1da177e4 1440 static struct itimerspec zero_it;
e4b76555
TA
1441
1442 memset(it, 0, sizeof *it);
1443 it->it_value = *rqtp;
1da177e4
LT
1444
1445 spin_lock_irq(&timer.it_lock);
e4b76555 1446 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1da177e4
LT
1447 if (error) {
1448 spin_unlock_irq(&timer.it_lock);
1449 return error;
1450 }
1451
1452 while (!signal_pending(current)) {
1453 if (timer.it.cpu.expires.sched == 0) {
1454 /*
1455 * Our timer fired and was reset.
1456 */
1457 spin_unlock_irq(&timer.it_lock);
1458 return 0;
1459 }
1460
1461 /*
1462 * Block until cpu_timer_fire (or a signal) wakes us.
1463 */
1464 __set_current_state(TASK_INTERRUPTIBLE);
1465 spin_unlock_irq(&timer.it_lock);
1466 schedule();
1467 spin_lock_irq(&timer.it_lock);
1468 }
1469
1470 /*
1471 * We were interrupted by a signal.
1472 */
1473 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
e4b76555 1474 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1da177e4
LT
1475 spin_unlock_irq(&timer.it_lock);
1476
e4b76555 1477 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1da177e4
LT
1478 /*
1479 * It actually did fire already.
1480 */
1481 return 0;
1482 }
1483
e4b76555
TA
1484 error = -ERESTART_RESTARTBLOCK;
1485 }
1486
1487 return error;
1488}
1489
1490int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1491 struct timespec *rqtp, struct timespec __user *rmtp)
1492{
1493 struct restart_block *restart_block =
1494 &current_thread_info()->restart_block;
1495 struct itimerspec it;
1496 int error;
1497
1498 /*
1499 * Diagnose required errors first.
1500 */
1501 if (CPUCLOCK_PERTHREAD(which_clock) &&
1502 (CPUCLOCK_PID(which_clock) == 0 ||
1503 CPUCLOCK_PID(which_clock) == current->pid))
1504 return -EINVAL;
1505
1506 error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1507
1508 if (error == -ERESTART_RESTARTBLOCK) {
1509
1510 if (flags & TIMER_ABSTIME)
1511 return -ERESTARTNOHAND;
1da177e4 1512 /*
e4b76555
TA
1513 * Report back to the user the time still remaining.
1514 */
1515 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1da177e4
LT
1516 return -EFAULT;
1517
1711ef38 1518 restart_block->fn = posix_cpu_nsleep_restart;
1da177e4 1519 restart_block->arg0 = which_clock;
97735f25 1520 restart_block->arg1 = (unsigned long) rmtp;
1da177e4
LT
1521 restart_block->arg2 = rqtp->tv_sec;
1522 restart_block->arg3 = rqtp->tv_nsec;
1da177e4 1523 }
1da177e4
LT
1524 return error;
1525}
1526
1711ef38 1527long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1da177e4
LT
1528{
1529 clockid_t which_clock = restart_block->arg0;
97735f25
TG
1530 struct timespec __user *rmtp;
1531 struct timespec t;
e4b76555
TA
1532 struct itimerspec it;
1533 int error;
97735f25
TG
1534
1535 rmtp = (struct timespec __user *) restart_block->arg1;
1536 t.tv_sec = restart_block->arg2;
1537 t.tv_nsec = restart_block->arg3;
1538
1da177e4 1539 restart_block->fn = do_no_restart_syscall;
e4b76555
TA
1540 error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1541
1542 if (error == -ERESTART_RESTARTBLOCK) {
1543 /*
1544 * Report back to the user the time still remaining.
1545 */
1546 if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1547 return -EFAULT;
1548
1549 restart_block->fn = posix_cpu_nsleep_restart;
1550 restart_block->arg0 = which_clock;
1551 restart_block->arg1 = (unsigned long) rmtp;
1552 restart_block->arg2 = t.tv_sec;
1553 restart_block->arg3 = t.tv_nsec;
1554 }
1555 return error;
1556
1da177e4
LT
1557}
1558
1559
1560#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1561#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1562
a924b04d
TG
1563static int process_cpu_clock_getres(const clockid_t which_clock,
1564 struct timespec *tp)
1da177e4
LT
1565{
1566 return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1567}
a924b04d
TG
1568static int process_cpu_clock_get(const clockid_t which_clock,
1569 struct timespec *tp)
1da177e4
LT
1570{
1571 return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1572}
1573static int process_cpu_timer_create(struct k_itimer *timer)
1574{
1575 timer->it_clock = PROCESS_CLOCK;
1576 return posix_cpu_timer_create(timer);
1577}
a924b04d 1578static int process_cpu_nsleep(const clockid_t which_clock, int flags,
97735f25
TG
1579 struct timespec *rqtp,
1580 struct timespec __user *rmtp)
1da177e4 1581{
97735f25 1582 return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1da177e4 1583}
1711ef38
TA
1584static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1585{
1586 return -EINVAL;
1587}
a924b04d
TG
1588static int thread_cpu_clock_getres(const clockid_t which_clock,
1589 struct timespec *tp)
1da177e4
LT
1590{
1591 return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1592}
a924b04d
TG
1593static int thread_cpu_clock_get(const clockid_t which_clock,
1594 struct timespec *tp)
1da177e4
LT
1595{
1596 return posix_cpu_clock_get(THREAD_CLOCK, tp);
1597}
1598static int thread_cpu_timer_create(struct k_itimer *timer)
1599{
1600 timer->it_clock = THREAD_CLOCK;
1601 return posix_cpu_timer_create(timer);
1602}
a924b04d 1603static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
97735f25 1604 struct timespec *rqtp, struct timespec __user *rmtp)
1da177e4
LT
1605{
1606 return -EINVAL;
1607}
1711ef38
TA
1608static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
1609{
1610 return -EINVAL;
1611}
1da177e4
LT
1612
1613static __init int init_posix_cpu_timers(void)
1614{
1615 struct k_clock process = {
1616 .clock_getres = process_cpu_clock_getres,
1617 .clock_get = process_cpu_clock_get,
1618 .clock_set = do_posix_clock_nosettime,
1619 .timer_create = process_cpu_timer_create,
1620 .nsleep = process_cpu_nsleep,
1711ef38 1621 .nsleep_restart = process_cpu_nsleep_restart,
1da177e4
LT
1622 };
1623 struct k_clock thread = {
1624 .clock_getres = thread_cpu_clock_getres,
1625 .clock_get = thread_cpu_clock_get,
1626 .clock_set = do_posix_clock_nosettime,
1627 .timer_create = thread_cpu_timer_create,
1628 .nsleep = thread_cpu_nsleep,
1711ef38 1629 .nsleep_restart = thread_cpu_nsleep_restart,
1da177e4 1630 };
8356b5f9 1631 struct timespec ts;
1da177e4
LT
1632
1633 register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1634 register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1635
a42548a1 1636 cputime_to_timespec(cputime_one_jiffy, &ts);
8356b5f9
SG
1637 onecputick = ts.tv_nsec;
1638 WARN_ON(ts.tv_sec != 0);
1639
1da177e4
LT
1640 return 0;
1641}
1642__initcall(init_posix_cpu_timers);