ARM: EXYNOS: Add missing definition for IRQ_I2S0
[linux-2.6.git] / kernel / posix-cpu-timers.c
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 <linux/errno.h>
8 #include <linux/math64.h>
9 #include <asm/uaccess.h>
10 #include <linux/kernel_stat.h>
11 #include <trace/events/timer.h>
12
13 /*
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.
18  */
19 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
20 {
21         cputime_t cputime = secs_to_cputime(rlim_new);
22
23         spin_lock_irq(&task->sighand->siglock);
24         set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
25         spin_unlock_irq(&task->sighand->siglock);
26 }
27
28 static int check_clock(const clockid_t which_clock)
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         rcu_read_lock();
41         p = find_task_by_vpid(pid);
42         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
43                    same_thread_group(p, current) : has_group_leader_pid(p))) {
44                 error = -EINVAL;
45         }
46         rcu_read_unlock();
47
48         return error;
49 }
50
51 static inline union cpu_time_count
52 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
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) {
57                 ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
58         } else {
59                 ret.cpu = timespec_to_cputime(tp);
60         }
61         return ret;
62 }
63
64 static void sample_to_timespec(const clockid_t which_clock,
65                                union cpu_time_count cpu,
66                                struct timespec *tp)
67 {
68         if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
69                 *tp = ns_to_timespec(cpu.sched);
70         else
71                 cputime_to_timespec(cpu.cpu, tp);
72 }
73
74 static inline int cpu_time_before(const clockid_t which_clock,
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 now.cpu < then.cpu;
82         }
83 }
84 static inline void cpu_time_add(const clockid_t which_clock,
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 += val.cpu;
92         }
93 }
94 static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
95                                                 union cpu_time_count a,
96                                                 union cpu_time_count b)
97 {
98         if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
99                 a.sched -= b.sched;
100         }  else {
101                 a.cpu -= b.cpu;
102         }
103         return a;
104 }
105
106 /*
107  * Update expiry time from increment, and increase overrun count,
108  * given the current clock sample.
109  */
110 static void bump_cpu_timer(struct k_itimer *timer,
111                                   union cpu_time_count now)
112 {
113         int i;
114
115         if (timer->it.cpu.incr.sched == 0)
116                 return;
117
118         if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
119                 unsigned long long delta, incr;
120
121                 if (now.sched < timer->it.cpu.expires.sched)
122                         return;
123                 incr = timer->it.cpu.incr.sched;
124                 delta = now.sched + incr - timer->it.cpu.expires.sched;
125                 /* Don't use (incr*2 < delta), incr*2 might overflow. */
126                 for (i = 0; incr < delta - incr; i++)
127                         incr = incr << 1;
128                 for (; i >= 0; incr >>= 1, i--) {
129                         if (delta < incr)
130                                 continue;
131                         timer->it.cpu.expires.sched += incr;
132                         timer->it_overrun += 1 << i;
133                         delta -= incr;
134                 }
135         } else {
136                 cputime_t delta, incr;
137
138                 if (now.cpu < timer->it.cpu.expires.cpu)
139                         return;
140                 incr = timer->it.cpu.incr.cpu;
141                 delta = now.cpu + incr - timer->it.cpu.expires.cpu;
142                 /* Don't use (incr*2 < delta), incr*2 might overflow. */
143                 for (i = 0; incr < delta - incr; i++)
144                              incr += incr;
145                 for (; i >= 0; incr = incr >> 1, i--) {
146                         if (delta < incr)
147                                 continue;
148                         timer->it.cpu.expires.cpu += incr;
149                         timer->it_overrun += 1 << i;
150                         delta -= incr;
151                 }
152         }
153 }
154
155 static inline cputime_t prof_ticks(struct task_struct *p)
156 {
157         return p->utime + p->stime;
158 }
159 static inline cputime_t virt_ticks(struct task_struct *p)
160 {
161         return p->utime;
162 }
163
164 static int
165 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
166 {
167         int error = check_clock(which_clock);
168         if (!error) {
169                 tp->tv_sec = 0;
170                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
171                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
172                         /*
173                          * If sched_clock is using a cycle counter, we
174                          * don't have any idea of its true resolution
175                          * exported, but it is much more than 1s/HZ.
176                          */
177                         tp->tv_nsec = 1;
178                 }
179         }
180         return error;
181 }
182
183 static int
184 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
185 {
186         /*
187          * You can never reset a CPU clock, but we check for other errors
188          * in the call before failing with EPERM.
189          */
190         int error = check_clock(which_clock);
191         if (error == 0) {
192                 error = -EPERM;
193         }
194         return error;
195 }
196
197
198 /*
199  * Sample a per-thread clock for the given task.
200  */
201 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
202                             union cpu_time_count *cpu)
203 {
204         switch (CPUCLOCK_WHICH(which_clock)) {
205         default:
206                 return -EINVAL;
207         case CPUCLOCK_PROF:
208                 cpu->cpu = prof_ticks(p);
209                 break;
210         case CPUCLOCK_VIRT:
211                 cpu->cpu = virt_ticks(p);
212                 break;
213         case CPUCLOCK_SCHED:
214                 cpu->sched = task_sched_runtime(p);
215                 break;
216         }
217         return 0;
218 }
219
220 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
221 {
222         struct signal_struct *sig = tsk->signal;
223         struct task_struct *t;
224
225         times->utime = sig->utime;
226         times->stime = sig->stime;
227         times->sum_exec_runtime = sig->sum_sched_runtime;
228
229         rcu_read_lock();
230         /* make sure we can trust tsk->thread_group list */
231         if (!likely(pid_alive(tsk)))
232                 goto out;
233
234         t = tsk;
235         do {
236                 times->utime += t->utime;
237                 times->stime += t->stime;
238                 times->sum_exec_runtime += task_sched_runtime(t);
239         } while_each_thread(tsk, t);
240 out:
241         rcu_read_unlock();
242 }
243
244 static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
245 {
246         if (b->utime > a->utime)
247                 a->utime = b->utime;
248
249         if (b->stime > a->stime)
250                 a->stime = b->stime;
251
252         if (b->sum_exec_runtime > a->sum_exec_runtime)
253                 a->sum_exec_runtime = b->sum_exec_runtime;
254 }
255
256 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
257 {
258         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
259         struct task_cputime sum;
260         unsigned long flags;
261
262         if (!cputimer->running) {
263                 /*
264                  * The POSIX timer interface allows for absolute time expiry
265                  * values through the TIMER_ABSTIME flag, therefore we have
266                  * to synchronize the timer to the clock every time we start
267                  * it.
268                  */
269                 thread_group_cputime(tsk, &sum);
270                 raw_spin_lock_irqsave(&cputimer->lock, flags);
271                 cputimer->running = 1;
272                 update_gt_cputime(&cputimer->cputime, &sum);
273         } else
274                 raw_spin_lock_irqsave(&cputimer->lock, flags);
275         *times = cputimer->cputime;
276         raw_spin_unlock_irqrestore(&cputimer->lock, flags);
277 }
278
279 /*
280  * Sample a process (thread group) clock for the given group_leader task.
281  * Must be called with tasklist_lock held for reading.
282  */
283 static int cpu_clock_sample_group(const clockid_t which_clock,
284                                   struct task_struct *p,
285                                   union cpu_time_count *cpu)
286 {
287         struct task_cputime cputime;
288
289         switch (CPUCLOCK_WHICH(which_clock)) {
290         default:
291                 return -EINVAL;
292         case CPUCLOCK_PROF:
293                 thread_group_cputime(p, &cputime);
294                 cpu->cpu = cputime.utime + cputime.stime;
295                 break;
296         case CPUCLOCK_VIRT:
297                 thread_group_cputime(p, &cputime);
298                 cpu->cpu = cputime.utime;
299                 break;
300         case CPUCLOCK_SCHED:
301                 thread_group_cputime(p, &cputime);
302                 cpu->sched = cputime.sum_exec_runtime;
303                 break;
304         }
305         return 0;
306 }
307
308
309 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
310 {
311         const pid_t pid = CPUCLOCK_PID(which_clock);
312         int error = -EINVAL;
313         union cpu_time_count rtn;
314
315         if (pid == 0) {
316                 /*
317                  * Special case constant value for our own clocks.
318                  * We don't have to do any lookup to find ourselves.
319                  */
320                 if (CPUCLOCK_PERTHREAD(which_clock)) {
321                         /*
322                          * Sampling just ourselves we can do with no locking.
323                          */
324                         error = cpu_clock_sample(which_clock,
325                                                  current, &rtn);
326                 } else {
327                         read_lock(&tasklist_lock);
328                         error = cpu_clock_sample_group(which_clock,
329                                                        current, &rtn);
330                         read_unlock(&tasklist_lock);
331                 }
332         } else {
333                 /*
334                  * Find the given PID, and validate that the caller
335                  * should be able to see it.
336                  */
337                 struct task_struct *p;
338                 rcu_read_lock();
339                 p = find_task_by_vpid(pid);
340                 if (p) {
341                         if (CPUCLOCK_PERTHREAD(which_clock)) {
342                                 if (same_thread_group(p, current)) {
343                                         error = cpu_clock_sample(which_clock,
344                                                                  p, &rtn);
345                                 }
346                         } else {
347                                 read_lock(&tasklist_lock);
348                                 if (thread_group_leader(p) && p->sighand) {
349                                         error =
350                                             cpu_clock_sample_group(which_clock,
351                                                                    p, &rtn);
352                                 }
353                                 read_unlock(&tasklist_lock);
354                         }
355                 }
356                 rcu_read_unlock();
357         }
358
359         if (error)
360                 return error;
361         sample_to_timespec(which_clock, rtn, tp);
362         return 0;
363 }
364
365
366 /*
367  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
368  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
369  * new timer already all-zeros initialized.
370  */
371 static int posix_cpu_timer_create(struct k_itimer *new_timer)
372 {
373         int ret = 0;
374         const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
375         struct task_struct *p;
376
377         if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
378                 return -EINVAL;
379
380         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
381
382         rcu_read_lock();
383         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
384                 if (pid == 0) {
385                         p = current;
386                 } else {
387                         p = find_task_by_vpid(pid);
388                         if (p && !same_thread_group(p, current))
389                                 p = NULL;
390                 }
391         } else {
392                 if (pid == 0) {
393                         p = current->group_leader;
394                 } else {
395                         p = find_task_by_vpid(pid);
396                         if (p && !has_group_leader_pid(p))
397                                 p = NULL;
398                 }
399         }
400         new_timer->it.cpu.task = p;
401         if (p) {
402                 get_task_struct(p);
403         } else {
404                 ret = -EINVAL;
405         }
406         rcu_read_unlock();
407
408         return ret;
409 }
410
411 /*
412  * Clean up a CPU-clock timer that is about to be destroyed.
413  * This is called from timer deletion with the timer already locked.
414  * If we return TIMER_RETRY, it's necessary to release the timer's lock
415  * and try again.  (This happens when the timer is in the middle of firing.)
416  */
417 static int posix_cpu_timer_del(struct k_itimer *timer)
418 {
419         struct task_struct *p = timer->it.cpu.task;
420         int ret = 0;
421
422         if (likely(p != NULL)) {
423                 read_lock(&tasklist_lock);
424                 if (unlikely(p->sighand == NULL)) {
425                         /*
426                          * We raced with the reaping of the task.
427                          * The deletion should have cleared us off the list.
428                          */
429                         BUG_ON(!list_empty(&timer->it.cpu.entry));
430                 } else {
431                         spin_lock(&p->sighand->siglock);
432                         if (timer->it.cpu.firing)
433                                 ret = TIMER_RETRY;
434                         else
435                                 list_del(&timer->it.cpu.entry);
436                         spin_unlock(&p->sighand->siglock);
437                 }
438                 read_unlock(&tasklist_lock);
439
440                 if (!ret)
441                         put_task_struct(p);
442         }
443
444         return ret;
445 }
446
447 /*
448  * Clean out CPU timers still ticking when a thread exited.  The task
449  * pointer is cleared, and the expiry time is replaced with the residual
450  * time for later timer_gettime calls to return.
451  * This must be called with the siglock held.
452  */
453 static void cleanup_timers(struct list_head *head,
454                            cputime_t utime, cputime_t stime,
455                            unsigned long long sum_exec_runtime)
456 {
457         struct cpu_timer_list *timer, *next;
458         cputime_t ptime = utime + stime;
459
460         list_for_each_entry_safe(timer, next, head, entry) {
461                 list_del_init(&timer->entry);
462                 if (timer->expires.cpu < ptime) {
463                         timer->expires.cpu = 0;
464                 } else {
465                         timer->expires.cpu -= ptime;
466                 }
467         }
468
469         ++head;
470         list_for_each_entry_safe(timer, next, head, entry) {
471                 list_del_init(&timer->entry);
472                 if (timer->expires.cpu < utime) {
473                         timer->expires.cpu = 0;
474                 } else {
475                         timer->expires.cpu -= utime;
476                 }
477         }
478
479         ++head;
480         list_for_each_entry_safe(timer, next, head, entry) {
481                 list_del_init(&timer->entry);
482                 if (timer->expires.sched < sum_exec_runtime) {
483                         timer->expires.sched = 0;
484                 } else {
485                         timer->expires.sched -= sum_exec_runtime;
486                 }
487         }
488 }
489
490 /*
491  * These are both called with the siglock held, when the current thread
492  * is being reaped.  When the final (leader) thread in the group is reaped,
493  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
494  */
495 void posix_cpu_timers_exit(struct task_struct *tsk)
496 {
497         cleanup_timers(tsk->cpu_timers,
498                        tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
499
500 }
501 void posix_cpu_timers_exit_group(struct task_struct *tsk)
502 {
503         struct signal_struct *const sig = tsk->signal;
504
505         cleanup_timers(tsk->signal->cpu_timers,
506                        tsk->utime + sig->utime, tsk->stime + sig->stime,
507                        tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
508 }
509
510 static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
511 {
512         /*
513          * That's all for this thread or process.
514          * We leave our residual in expires to be reported.
515          */
516         put_task_struct(timer->it.cpu.task);
517         timer->it.cpu.task = NULL;
518         timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
519                                              timer->it.cpu.expires,
520                                              now);
521 }
522
523 static inline int expires_gt(cputime_t expires, cputime_t new_exp)
524 {
525         return expires == 0 || expires > new_exp;
526 }
527
528 /*
529  * Insert the timer on the appropriate list before any timers that
530  * expire later.  This must be called with the tasklist_lock held
531  * for reading, interrupts disabled and p->sighand->siglock taken.
532  */
533 static void arm_timer(struct k_itimer *timer)
534 {
535         struct task_struct *p = timer->it.cpu.task;
536         struct list_head *head, *listpos;
537         struct task_cputime *cputime_expires;
538         struct cpu_timer_list *const nt = &timer->it.cpu;
539         struct cpu_timer_list *next;
540
541         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
542                 head = p->cpu_timers;
543                 cputime_expires = &p->cputime_expires;
544         } else {
545                 head = p->signal->cpu_timers;
546                 cputime_expires = &p->signal->cputime_expires;
547         }
548         head += CPUCLOCK_WHICH(timer->it_clock);
549
550         listpos = head;
551         list_for_each_entry(next, head, entry) {
552                 if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
553                         break;
554                 listpos = &next->entry;
555         }
556         list_add(&nt->entry, listpos);
557
558         if (listpos == head) {
559                 union cpu_time_count *exp = &nt->expires;
560
561                 /*
562                  * We are the new earliest-expiring POSIX 1.b timer, hence
563                  * need to update expiration cache. Take into account that
564                  * for process timers we share expiration cache with itimers
565                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
566                  */
567
568                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
569                 case CPUCLOCK_PROF:
570                         if (expires_gt(cputime_expires->prof_exp, exp->cpu))
571                                 cputime_expires->prof_exp = exp->cpu;
572                         break;
573                 case CPUCLOCK_VIRT:
574                         if (expires_gt(cputime_expires->virt_exp, exp->cpu))
575                                 cputime_expires->virt_exp = exp->cpu;
576                         break;
577                 case CPUCLOCK_SCHED:
578                         if (cputime_expires->sched_exp == 0 ||
579                             cputime_expires->sched_exp > exp->sched)
580                                 cputime_expires->sched_exp = exp->sched;
581                         break;
582                 }
583         }
584 }
585
586 /*
587  * The timer is locked, fire it and arrange for its reload.
588  */
589 static void cpu_timer_fire(struct k_itimer *timer)
590 {
591         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
592                 /*
593                  * User don't want any signal.
594                  */
595                 timer->it.cpu.expires.sched = 0;
596         } else if (unlikely(timer->sigq == NULL)) {
597                 /*
598                  * This a special case for clock_nanosleep,
599                  * not a normal timer from sys_timer_create.
600                  */
601                 wake_up_process(timer->it_process);
602                 timer->it.cpu.expires.sched = 0;
603         } else if (timer->it.cpu.incr.sched == 0) {
604                 /*
605                  * One-shot timer.  Clear it as soon as it's fired.
606                  */
607                 posix_timer_event(timer, 0);
608                 timer->it.cpu.expires.sched = 0;
609         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
610                 /*
611                  * The signal did not get queued because the signal
612                  * was ignored, so we won't get any callback to
613                  * reload the timer.  But we need to keep it
614                  * ticking in case the signal is deliverable next time.
615                  */
616                 posix_cpu_timer_schedule(timer);
617         }
618 }
619
620 /*
621  * Sample a process (thread group) timer for the given group_leader task.
622  * Must be called with tasklist_lock held for reading.
623  */
624 static int cpu_timer_sample_group(const clockid_t which_clock,
625                                   struct task_struct *p,
626                                   union cpu_time_count *cpu)
627 {
628         struct task_cputime cputime;
629
630         thread_group_cputimer(p, &cputime);
631         switch (CPUCLOCK_WHICH(which_clock)) {
632         default:
633                 return -EINVAL;
634         case CPUCLOCK_PROF:
635                 cpu->cpu = cputime.utime + cputime.stime;
636                 break;
637         case CPUCLOCK_VIRT:
638                 cpu->cpu = cputime.utime;
639                 break;
640         case CPUCLOCK_SCHED:
641                 cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
642                 break;
643         }
644         return 0;
645 }
646
647 /*
648  * Guts of sys_timer_settime for CPU timers.
649  * This is called with the timer locked and interrupts disabled.
650  * If we return TIMER_RETRY, it's necessary to release the timer's lock
651  * and try again.  (This happens when the timer is in the middle of firing.)
652  */
653 static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
654                                struct itimerspec *new, struct itimerspec *old)
655 {
656         struct task_struct *p = timer->it.cpu.task;
657         union cpu_time_count old_expires, new_expires, old_incr, val;
658         int ret;
659
660         if (unlikely(p == NULL)) {
661                 /*
662                  * Timer refers to a dead task's clock.
663                  */
664                 return -ESRCH;
665         }
666
667         new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
668
669         read_lock(&tasklist_lock);
670         /*
671          * We need the tasklist_lock to protect against reaping that
672          * clears p->sighand.  If p has just been reaped, we can no
673          * longer get any information about it at all.
674          */
675         if (unlikely(p->sighand == NULL)) {
676                 read_unlock(&tasklist_lock);
677                 put_task_struct(p);
678                 timer->it.cpu.task = NULL;
679                 return -ESRCH;
680         }
681
682         /*
683          * Disarm any old timer after extracting its expiry time.
684          */
685         BUG_ON(!irqs_disabled());
686
687         ret = 0;
688         old_incr = timer->it.cpu.incr;
689         spin_lock(&p->sighand->siglock);
690         old_expires = timer->it.cpu.expires;
691         if (unlikely(timer->it.cpu.firing)) {
692                 timer->it.cpu.firing = -1;
693                 ret = TIMER_RETRY;
694         } else
695                 list_del_init(&timer->it.cpu.entry);
696
697         /*
698          * We need to sample the current value to convert the new
699          * value from to relative and absolute, and to convert the
700          * old value from absolute to relative.  To set a process
701          * timer, we need a sample to balance the thread expiry
702          * times (in arm_timer).  With an absolute time, we must
703          * check if it's already passed.  In short, we need a sample.
704          */
705         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
706                 cpu_clock_sample(timer->it_clock, p, &val);
707         } else {
708                 cpu_timer_sample_group(timer->it_clock, p, &val);
709         }
710
711         if (old) {
712                 if (old_expires.sched == 0) {
713                         old->it_value.tv_sec = 0;
714                         old->it_value.tv_nsec = 0;
715                 } else {
716                         /*
717                          * Update the timer in case it has
718                          * overrun already.  If it has,
719                          * we'll report it as having overrun
720                          * and with the next reloaded timer
721                          * already ticking, though we are
722                          * swallowing that pending
723                          * notification here to install the
724                          * new setting.
725                          */
726                         bump_cpu_timer(timer, val);
727                         if (cpu_time_before(timer->it_clock, val,
728                                             timer->it.cpu.expires)) {
729                                 old_expires = cpu_time_sub(
730                                         timer->it_clock,
731                                         timer->it.cpu.expires, val);
732                                 sample_to_timespec(timer->it_clock,
733                                                    old_expires,
734                                                    &old->it_value);
735                         } else {
736                                 old->it_value.tv_nsec = 1;
737                                 old->it_value.tv_sec = 0;
738                         }
739                 }
740         }
741
742         if (unlikely(ret)) {
743                 /*
744                  * We are colliding with the timer actually firing.
745                  * Punt after filling in the timer's old value, and
746                  * disable this firing since we are already reporting
747                  * it as an overrun (thanks to bump_cpu_timer above).
748                  */
749                 spin_unlock(&p->sighand->siglock);
750                 read_unlock(&tasklist_lock);
751                 goto out;
752         }
753
754         if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
755                 cpu_time_add(timer->it_clock, &new_expires, val);
756         }
757
758         /*
759          * Install the new expiry time (or zero).
760          * For a timer with no notification action, we don't actually
761          * arm the timer (we'll just fake it for timer_gettime).
762          */
763         timer->it.cpu.expires = new_expires;
764         if (new_expires.sched != 0 &&
765             cpu_time_before(timer->it_clock, val, new_expires)) {
766                 arm_timer(timer);
767         }
768
769         spin_unlock(&p->sighand->siglock);
770         read_unlock(&tasklist_lock);
771
772         /*
773          * Install the new reload setting, and
774          * set up the signal and overrun bookkeeping.
775          */
776         timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
777                                                 &new->it_interval);
778
779         /*
780          * This acts as a modification timestamp for the timer,
781          * so any automatic reload attempt will punt on seeing
782          * that we have reset the timer manually.
783          */
784         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
785                 ~REQUEUE_PENDING;
786         timer->it_overrun_last = 0;
787         timer->it_overrun = -1;
788
789         if (new_expires.sched != 0 &&
790             !cpu_time_before(timer->it_clock, val, new_expires)) {
791                 /*
792                  * The designated time already passed, so we notify
793                  * immediately, even if the thread never runs to
794                  * accumulate more time on this clock.
795                  */
796                 cpu_timer_fire(timer);
797         }
798
799         ret = 0;
800  out:
801         if (old) {
802                 sample_to_timespec(timer->it_clock,
803                                    old_incr, &old->it_interval);
804         }
805         return ret;
806 }
807
808 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
809 {
810         union cpu_time_count now;
811         struct task_struct *p = timer->it.cpu.task;
812         int clear_dead;
813
814         /*
815          * Easy part: convert the reload time.
816          */
817         sample_to_timespec(timer->it_clock,
818                            timer->it.cpu.incr, &itp->it_interval);
819
820         if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all.  */
821                 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
822                 return;
823         }
824
825         if (unlikely(p == NULL)) {
826                 /*
827                  * This task already died and the timer will never fire.
828                  * In this case, expires is actually the dead value.
829                  */
830         dead:
831                 sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
832                                    &itp->it_value);
833                 return;
834         }
835
836         /*
837          * Sample the clock to take the difference with the expiry time.
838          */
839         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
840                 cpu_clock_sample(timer->it_clock, p, &now);
841                 clear_dead = p->exit_state;
842         } else {
843                 read_lock(&tasklist_lock);
844                 if (unlikely(p->sighand == NULL)) {
845                         /*
846                          * The process has been reaped.
847                          * We can't even collect a sample any more.
848                          * Call the timer disarmed, nothing else to do.
849                          */
850                         put_task_struct(p);
851                         timer->it.cpu.task = NULL;
852                         timer->it.cpu.expires.sched = 0;
853                         read_unlock(&tasklist_lock);
854                         goto dead;
855                 } else {
856                         cpu_timer_sample_group(timer->it_clock, p, &now);
857                         clear_dead = (unlikely(p->exit_state) &&
858                                       thread_group_empty(p));
859                 }
860                 read_unlock(&tasklist_lock);
861         }
862
863         if (unlikely(clear_dead)) {
864                 /*
865                  * We've noticed that the thread is dead, but
866                  * not yet reaped.  Take this opportunity to
867                  * drop our task ref.
868                  */
869                 clear_dead_task(timer, now);
870                 goto dead;
871         }
872
873         if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
874                 sample_to_timespec(timer->it_clock,
875                                    cpu_time_sub(timer->it_clock,
876                                                 timer->it.cpu.expires, now),
877                                    &itp->it_value);
878         } else {
879                 /*
880                  * The timer should have expired already, but the firing
881                  * hasn't taken place yet.  Say it's just about to expire.
882                  */
883                 itp->it_value.tv_nsec = 1;
884                 itp->it_value.tv_sec = 0;
885         }
886 }
887
888 /*
889  * Check for any per-thread CPU timers that have fired and move them off
890  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
891  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
892  */
893 static void check_thread_timers(struct task_struct *tsk,
894                                 struct list_head *firing)
895 {
896         int maxfire;
897         struct list_head *timers = tsk->cpu_timers;
898         struct signal_struct *const sig = tsk->signal;
899         unsigned long soft;
900
901         maxfire = 20;
902         tsk->cputime_expires.prof_exp = 0;
903         while (!list_empty(timers)) {
904                 struct cpu_timer_list *t = list_first_entry(timers,
905                                                       struct cpu_timer_list,
906                                                       entry);
907                 if (!--maxfire || prof_ticks(tsk) < t->expires.cpu) {
908                         tsk->cputime_expires.prof_exp = t->expires.cpu;
909                         break;
910                 }
911                 t->firing = 1;
912                 list_move_tail(&t->entry, firing);
913         }
914
915         ++timers;
916         maxfire = 20;
917         tsk->cputime_expires.virt_exp = 0;
918         while (!list_empty(timers)) {
919                 struct cpu_timer_list *t = list_first_entry(timers,
920                                                       struct cpu_timer_list,
921                                                       entry);
922                 if (!--maxfire || virt_ticks(tsk) < t->expires.cpu) {
923                         tsk->cputime_expires.virt_exp = t->expires.cpu;
924                         break;
925                 }
926                 t->firing = 1;
927                 list_move_tail(&t->entry, firing);
928         }
929
930         ++timers;
931         maxfire = 20;
932         tsk->cputime_expires.sched_exp = 0;
933         while (!list_empty(timers)) {
934                 struct cpu_timer_list *t = list_first_entry(timers,
935                                                       struct cpu_timer_list,
936                                                       entry);
937                 if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
938                         tsk->cputime_expires.sched_exp = t->expires.sched;
939                         break;
940                 }
941                 t->firing = 1;
942                 list_move_tail(&t->entry, firing);
943         }
944
945         /*
946          * Check for the special case thread timers.
947          */
948         soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
949         if (soft != RLIM_INFINITY) {
950                 unsigned long hard =
951                         ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
952
953                 if (hard != RLIM_INFINITY &&
954                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
955                         /*
956                          * At the hard limit, we just die.
957                          * No need to calculate anything else now.
958                          */
959                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
960                         return;
961                 }
962                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
963                         /*
964                          * At the soft limit, send a SIGXCPU every second.
965                          */
966                         if (soft < hard) {
967                                 soft += USEC_PER_SEC;
968                                 sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
969                         }
970                         printk(KERN_INFO
971                                 "RT Watchdog Timeout: %s[%d]\n",
972                                 tsk->comm, task_pid_nr(tsk));
973                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
974                 }
975         }
976 }
977
978 static void stop_process_timers(struct signal_struct *sig)
979 {
980         struct thread_group_cputimer *cputimer = &sig->cputimer;
981         unsigned long flags;
982
983         raw_spin_lock_irqsave(&cputimer->lock, flags);
984         cputimer->running = 0;
985         raw_spin_unlock_irqrestore(&cputimer->lock, flags);
986 }
987
988 static u32 onecputick;
989
990 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
991                              cputime_t *expires, cputime_t cur_time, int signo)
992 {
993         if (!it->expires)
994                 return;
995
996         if (cur_time >= it->expires) {
997                 if (it->incr) {
998                         it->expires += it->incr;
999                         it->error += it->incr_error;
1000                         if (it->error >= onecputick) {
1001                                 it->expires -= cputime_one_jiffy;
1002                                 it->error -= onecputick;
1003                         }
1004                 } else {
1005                         it->expires = 0;
1006                 }
1007
1008                 trace_itimer_expire(signo == SIGPROF ?
1009                                     ITIMER_PROF : ITIMER_VIRTUAL,
1010                                     tsk->signal->leader_pid, cur_time);
1011                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
1012         }
1013
1014         if (it->expires && (!*expires || it->expires < *expires)) {
1015                 *expires = it->expires;
1016         }
1017 }
1018
1019 /**
1020  * task_cputime_zero - Check a task_cputime struct for all zero fields.
1021  *
1022  * @cputime:    The struct to compare.
1023  *
1024  * Checks @cputime to see if all fields are zero.  Returns true if all fields
1025  * are zero, false if any field is nonzero.
1026  */
1027 static inline int task_cputime_zero(const struct task_cputime *cputime)
1028 {
1029         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
1030                 return 1;
1031         return 0;
1032 }
1033
1034 /*
1035  * Check for any per-thread CPU timers that have fired and move them
1036  * off the tsk->*_timers list onto the firing list.  Per-thread timers
1037  * have already been taken off.
1038  */
1039 static void check_process_timers(struct task_struct *tsk,
1040                                  struct list_head *firing)
1041 {
1042         int maxfire;
1043         struct signal_struct *const sig = tsk->signal;
1044         cputime_t utime, ptime, virt_expires, prof_expires;
1045         unsigned long long sum_sched_runtime, sched_expires;
1046         struct list_head *timers = sig->cpu_timers;
1047         struct task_cputime cputime;
1048         unsigned long soft;
1049
1050         /*
1051          * Collect the current process totals.
1052          */
1053         thread_group_cputimer(tsk, &cputime);
1054         utime = cputime.utime;
1055         ptime = utime + cputime.stime;
1056         sum_sched_runtime = cputime.sum_exec_runtime;
1057         maxfire = 20;
1058         prof_expires = 0;
1059         while (!list_empty(timers)) {
1060                 struct cpu_timer_list *tl = list_first_entry(timers,
1061                                                       struct cpu_timer_list,
1062                                                       entry);
1063                 if (!--maxfire || ptime < tl->expires.cpu) {
1064                         prof_expires = tl->expires.cpu;
1065                         break;
1066                 }
1067                 tl->firing = 1;
1068                 list_move_tail(&tl->entry, firing);
1069         }
1070
1071         ++timers;
1072         maxfire = 20;
1073         virt_expires = 0;
1074         while (!list_empty(timers)) {
1075                 struct cpu_timer_list *tl = list_first_entry(timers,
1076                                                       struct cpu_timer_list,
1077                                                       entry);
1078                 if (!--maxfire || utime < tl->expires.cpu) {
1079                         virt_expires = tl->expires.cpu;
1080                         break;
1081                 }
1082                 tl->firing = 1;
1083                 list_move_tail(&tl->entry, firing);
1084         }
1085
1086         ++timers;
1087         maxfire = 20;
1088         sched_expires = 0;
1089         while (!list_empty(timers)) {
1090                 struct cpu_timer_list *tl = list_first_entry(timers,
1091                                                       struct cpu_timer_list,
1092                                                       entry);
1093                 if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
1094                         sched_expires = tl->expires.sched;
1095                         break;
1096                 }
1097                 tl->firing = 1;
1098                 list_move_tail(&tl->entry, firing);
1099         }
1100
1101         /*
1102          * Check for the special case process timers.
1103          */
1104         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
1105                          SIGPROF);
1106         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
1107                          SIGVTALRM);
1108         soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
1109         if (soft != RLIM_INFINITY) {
1110                 unsigned long psecs = cputime_to_secs(ptime);
1111                 unsigned long hard =
1112                         ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
1113                 cputime_t x;
1114                 if (psecs >= hard) {
1115                         /*
1116                          * At the hard limit, we just die.
1117                          * No need to calculate anything else now.
1118                          */
1119                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
1120                         return;
1121                 }
1122                 if (psecs >= soft) {
1123                         /*
1124                          * At the soft limit, send a SIGXCPU every second.
1125                          */
1126                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
1127                         if (soft < hard) {
1128                                 soft++;
1129                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
1130                         }
1131                 }
1132                 x = secs_to_cputime(soft);
1133                 if (!prof_expires || x < prof_expires) {
1134                         prof_expires = x;
1135                 }
1136         }
1137
1138         sig->cputime_expires.prof_exp = prof_expires;
1139         sig->cputime_expires.virt_exp = virt_expires;
1140         sig->cputime_expires.sched_exp = sched_expires;
1141         if (task_cputime_zero(&sig->cputime_expires))
1142                 stop_process_timers(sig);
1143 }
1144
1145 /*
1146  * This is called from the signal code (via do_schedule_next_timer)
1147  * when the last timer signal was delivered and we have to reload the timer.
1148  */
1149 void posix_cpu_timer_schedule(struct k_itimer *timer)
1150 {
1151         struct task_struct *p = timer->it.cpu.task;
1152         union cpu_time_count now;
1153
1154         if (unlikely(p == NULL))
1155                 /*
1156                  * The task was cleaned up already, no future firings.
1157                  */
1158                 goto out;
1159
1160         /*
1161          * Fetch the current sample and update the timer's expiry time.
1162          */
1163         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1164                 cpu_clock_sample(timer->it_clock, p, &now);
1165                 bump_cpu_timer(timer, now);
1166                 if (unlikely(p->exit_state)) {
1167                         clear_dead_task(timer, now);
1168                         goto out;
1169                 }
1170                 read_lock(&tasklist_lock); /* arm_timer needs it.  */
1171                 spin_lock(&p->sighand->siglock);
1172         } else {
1173                 read_lock(&tasklist_lock);
1174                 if (unlikely(p->sighand == NULL)) {
1175                         /*
1176                          * The process has been reaped.
1177                          * We can't even collect a sample any more.
1178                          */
1179                         put_task_struct(p);
1180                         timer->it.cpu.task = p = NULL;
1181                         timer->it.cpu.expires.sched = 0;
1182                         goto out_unlock;
1183                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1184                         /*
1185                          * We've noticed that the thread is dead, but
1186                          * not yet reaped.  Take this opportunity to
1187                          * drop our task ref.
1188                          */
1189                         clear_dead_task(timer, now);
1190                         goto out_unlock;
1191                 }
1192                 spin_lock(&p->sighand->siglock);
1193                 cpu_timer_sample_group(timer->it_clock, p, &now);
1194                 bump_cpu_timer(timer, now);
1195                 /* Leave the tasklist_lock locked for the call below.  */
1196         }
1197
1198         /*
1199          * Now re-arm for the new expiry time.
1200          */
1201         BUG_ON(!irqs_disabled());
1202         arm_timer(timer);
1203         spin_unlock(&p->sighand->siglock);
1204
1205 out_unlock:
1206         read_unlock(&tasklist_lock);
1207
1208 out:
1209         timer->it_overrun_last = timer->it_overrun;
1210         timer->it_overrun = -1;
1211         ++timer->it_requeue_pending;
1212 }
1213
1214 /**
1215  * task_cputime_expired - Compare two task_cputime entities.
1216  *
1217  * @sample:     The task_cputime structure to be checked for expiration.
1218  * @expires:    Expiration times, against which @sample will be checked.
1219  *
1220  * Checks @sample against @expires to see if any field of @sample has expired.
1221  * Returns true if any field of the former is greater than the corresponding
1222  * field of the latter if the latter field is set.  Otherwise returns false.
1223  */
1224 static inline int task_cputime_expired(const struct task_cputime *sample,
1225                                         const struct task_cputime *expires)
1226 {
1227         if (expires->utime && sample->utime >= expires->utime)
1228                 return 1;
1229         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1230                 return 1;
1231         if (expires->sum_exec_runtime != 0 &&
1232             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1233                 return 1;
1234         return 0;
1235 }
1236
1237 /**
1238  * fastpath_timer_check - POSIX CPU timers fast path.
1239  *
1240  * @tsk:        The task (thread) being checked.
1241  *
1242  * Check the task and thread group timers.  If both are zero (there are no
1243  * timers set) return false.  Otherwise snapshot the task and thread group
1244  * timers and compare them with the corresponding expiration times.  Return
1245  * true if a timer has expired, else return false.
1246  */
1247 static inline int fastpath_timer_check(struct task_struct *tsk)
1248 {
1249         struct signal_struct *sig;
1250
1251         if (!task_cputime_zero(&tsk->cputime_expires)) {
1252                 struct task_cputime task_sample = {
1253                         .utime = tsk->utime,
1254                         .stime = tsk->stime,
1255                         .sum_exec_runtime = tsk->se.sum_exec_runtime
1256                 };
1257
1258                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1259                         return 1;
1260         }
1261
1262         sig = tsk->signal;
1263         if (sig->cputimer.running) {
1264                 struct task_cputime group_sample;
1265
1266                 raw_spin_lock(&sig->cputimer.lock);
1267                 group_sample = sig->cputimer.cputime;
1268                 raw_spin_unlock(&sig->cputimer.lock);
1269
1270                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1271                         return 1;
1272         }
1273
1274         return 0;
1275 }
1276
1277 /*
1278  * This is called from the timer interrupt handler.  The irq handler has
1279  * already updated our counts.  We need to check if any timers fire now.
1280  * Interrupts are disabled.
1281  */
1282 void run_posix_cpu_timers(struct task_struct *tsk)
1283 {
1284         LIST_HEAD(firing);
1285         struct k_itimer *timer, *next;
1286         unsigned long flags;
1287
1288         BUG_ON(!irqs_disabled());
1289
1290         /*
1291          * The fast path checks that there are no expired thread or thread
1292          * group timers.  If that's so, just return.
1293          */
1294         if (!fastpath_timer_check(tsk))
1295                 return;
1296
1297         if (!lock_task_sighand(tsk, &flags))
1298                 return;
1299         /*
1300          * Here we take off tsk->signal->cpu_timers[N] and
1301          * tsk->cpu_timers[N] all the timers that are firing, and
1302          * put them on the firing list.
1303          */
1304         check_thread_timers(tsk, &firing);
1305         /*
1306          * If there are any active process wide timers (POSIX 1.b, itimers,
1307          * RLIMIT_CPU) cputimer must be running.
1308          */
1309         if (tsk->signal->cputimer.running)
1310                 check_process_timers(tsk, &firing);
1311
1312         /*
1313          * We must release these locks before taking any timer's lock.
1314          * There is a potential race with timer deletion here, as the
1315          * siglock now protects our private firing list.  We have set
1316          * the firing flag in each timer, so that a deletion attempt
1317          * that gets the timer lock before we do will give it up and
1318          * spin until we've taken care of that timer below.
1319          */
1320         unlock_task_sighand(tsk, &flags);
1321
1322         /*
1323          * Now that all the timers on our list have the firing flag,
1324          * no one will touch their list entries but us.  We'll take
1325          * each timer's lock before clearing its firing flag, so no
1326          * timer call will interfere.
1327          */
1328         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1329                 int cpu_firing;
1330
1331                 spin_lock(&timer->it_lock);
1332                 list_del_init(&timer->it.cpu.entry);
1333                 cpu_firing = timer->it.cpu.firing;
1334                 timer->it.cpu.firing = 0;
1335                 /*
1336                  * The firing flag is -1 if we collided with a reset
1337                  * of the timer, which already reported this
1338                  * almost-firing as an overrun.  So don't generate an event.
1339                  */
1340                 if (likely(cpu_firing >= 0))
1341                         cpu_timer_fire(timer);
1342                 spin_unlock(&timer->it_lock);
1343         }
1344 }
1345
1346 /*
1347  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1348  * The tsk->sighand->siglock must be held by the caller.
1349  */
1350 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1351                            cputime_t *newval, cputime_t *oldval)
1352 {
1353         union cpu_time_count now;
1354
1355         BUG_ON(clock_idx == CPUCLOCK_SCHED);
1356         cpu_timer_sample_group(clock_idx, tsk, &now);
1357
1358         if (oldval) {
1359                 /*
1360                  * We are setting itimer. The *oldval is absolute and we update
1361                  * it to be relative, *newval argument is relative and we update
1362                  * it to be absolute.
1363                  */
1364                 if (*oldval) {
1365                         if (*oldval <= now.cpu) {
1366                                 /* Just about to fire. */
1367                                 *oldval = cputime_one_jiffy;
1368                         } else {
1369                                 *oldval -= now.cpu;
1370                         }
1371                 }
1372
1373                 if (!*newval)
1374                         return;
1375                 *newval += now.cpu;
1376         }
1377
1378         /*
1379          * Update expiration cache if we are the earliest timer, or eventually
1380          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1381          */
1382         switch (clock_idx) {
1383         case CPUCLOCK_PROF:
1384                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1385                         tsk->signal->cputime_expires.prof_exp = *newval;
1386                 break;
1387         case CPUCLOCK_VIRT:
1388                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1389                         tsk->signal->cputime_expires.virt_exp = *newval;
1390                 break;
1391         }
1392 }
1393
1394 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1395                             struct timespec *rqtp, struct itimerspec *it)
1396 {
1397         struct k_itimer timer;
1398         int error;
1399
1400         /*
1401          * Set up a temporary timer and then wait for it to go off.
1402          */
1403         memset(&timer, 0, sizeof timer);
1404         spin_lock_init(&timer.it_lock);
1405         timer.it_clock = which_clock;
1406         timer.it_overrun = -1;
1407         error = posix_cpu_timer_create(&timer);
1408         timer.it_process = current;
1409         if (!error) {
1410                 static struct itimerspec zero_it;
1411
1412                 memset(it, 0, sizeof *it);
1413                 it->it_value = *rqtp;
1414
1415                 spin_lock_irq(&timer.it_lock);
1416                 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1417                 if (error) {
1418                         spin_unlock_irq(&timer.it_lock);
1419                         return error;
1420                 }
1421
1422                 while (!signal_pending(current)) {
1423                         if (timer.it.cpu.expires.sched == 0) {
1424                                 /*
1425                                  * Our timer fired and was reset.
1426                                  */
1427                                 spin_unlock_irq(&timer.it_lock);
1428                                 return 0;
1429                         }
1430
1431                         /*
1432                          * Block until cpu_timer_fire (or a signal) wakes us.
1433                          */
1434                         __set_current_state(TASK_INTERRUPTIBLE);
1435                         spin_unlock_irq(&timer.it_lock);
1436                         schedule();
1437                         spin_lock_irq(&timer.it_lock);
1438                 }
1439
1440                 /*
1441                  * We were interrupted by a signal.
1442                  */
1443                 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1444                 posix_cpu_timer_set(&timer, 0, &zero_it, it);
1445                 spin_unlock_irq(&timer.it_lock);
1446
1447                 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1448                         /*
1449                          * It actually did fire already.
1450                          */
1451                         return 0;
1452                 }
1453
1454                 error = -ERESTART_RESTARTBLOCK;
1455         }
1456
1457         return error;
1458 }
1459
1460 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1461
1462 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1463                             struct timespec *rqtp, struct timespec __user *rmtp)
1464 {
1465         struct restart_block *restart_block =
1466                 &current_thread_info()->restart_block;
1467         struct itimerspec it;
1468         int error;
1469
1470         /*
1471          * Diagnose required errors first.
1472          */
1473         if (CPUCLOCK_PERTHREAD(which_clock) &&
1474             (CPUCLOCK_PID(which_clock) == 0 ||
1475              CPUCLOCK_PID(which_clock) == current->pid))
1476                 return -EINVAL;
1477
1478         error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1479
1480         if (error == -ERESTART_RESTARTBLOCK) {
1481
1482                 if (flags & TIMER_ABSTIME)
1483                         return -ERESTARTNOHAND;
1484                 /*
1485                  * Report back to the user the time still remaining.
1486                  */
1487                 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1488                         return -EFAULT;
1489
1490                 restart_block->fn = posix_cpu_nsleep_restart;
1491                 restart_block->nanosleep.clockid = which_clock;
1492                 restart_block->nanosleep.rmtp = rmtp;
1493                 restart_block->nanosleep.expires = timespec_to_ns(rqtp);
1494         }
1495         return error;
1496 }
1497
1498 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1499 {
1500         clockid_t which_clock = restart_block->nanosleep.clockid;
1501         struct timespec t;
1502         struct itimerspec it;
1503         int error;
1504
1505         t = ns_to_timespec(restart_block->nanosleep.expires);
1506
1507         error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1508
1509         if (error == -ERESTART_RESTARTBLOCK) {
1510                 struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
1511                 /*
1512                  * Report back to the user the time still remaining.
1513                  */
1514                 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1515                         return -EFAULT;
1516
1517                 restart_block->nanosleep.expires = timespec_to_ns(&t);
1518         }
1519         return error;
1520
1521 }
1522
1523 #define PROCESS_CLOCK   MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1524 #define THREAD_CLOCK    MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1525
1526 static int process_cpu_clock_getres(const clockid_t which_clock,
1527                                     struct timespec *tp)
1528 {
1529         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1530 }
1531 static int process_cpu_clock_get(const clockid_t which_clock,
1532                                  struct timespec *tp)
1533 {
1534         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1535 }
1536 static int process_cpu_timer_create(struct k_itimer *timer)
1537 {
1538         timer->it_clock = PROCESS_CLOCK;
1539         return posix_cpu_timer_create(timer);
1540 }
1541 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1542                               struct timespec *rqtp,
1543                               struct timespec __user *rmtp)
1544 {
1545         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1546 }
1547 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1548 {
1549         return -EINVAL;
1550 }
1551 static int thread_cpu_clock_getres(const clockid_t which_clock,
1552                                    struct timespec *tp)
1553 {
1554         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1555 }
1556 static int thread_cpu_clock_get(const clockid_t which_clock,
1557                                 struct timespec *tp)
1558 {
1559         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1560 }
1561 static int thread_cpu_timer_create(struct k_itimer *timer)
1562 {
1563         timer->it_clock = THREAD_CLOCK;
1564         return posix_cpu_timer_create(timer);
1565 }
1566
1567 struct k_clock clock_posix_cpu = {
1568         .clock_getres   = posix_cpu_clock_getres,
1569         .clock_set      = posix_cpu_clock_set,
1570         .clock_get      = posix_cpu_clock_get,
1571         .timer_create   = posix_cpu_timer_create,
1572         .nsleep         = posix_cpu_nsleep,
1573         .nsleep_restart = posix_cpu_nsleep_restart,
1574         .timer_set      = posix_cpu_timer_set,
1575         .timer_del      = posix_cpu_timer_del,
1576         .timer_get      = posix_cpu_timer_get,
1577 };
1578
1579 static __init int init_posix_cpu_timers(void)
1580 {
1581         struct k_clock process = {
1582                 .clock_getres   = process_cpu_clock_getres,
1583                 .clock_get      = process_cpu_clock_get,
1584                 .timer_create   = process_cpu_timer_create,
1585                 .nsleep         = process_cpu_nsleep,
1586                 .nsleep_restart = process_cpu_nsleep_restart,
1587         };
1588         struct k_clock thread = {
1589                 .clock_getres   = thread_cpu_clock_getres,
1590                 .clock_get      = thread_cpu_clock_get,
1591                 .timer_create   = thread_cpu_timer_create,
1592         };
1593         struct timespec ts;
1594
1595         posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1596         posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1597
1598         cputime_to_timespec(cputime_one_jiffy, &ts);
1599         onecputick = ts.tv_nsec;
1600         WARN_ON(ts.tv_sec != 0);
1601
1602         return 0;
1603 }
1604 __initcall(init_posix_cpu_timers);