Merge branch 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[platform/adaptation/renesas_rcar/renesas_kernel.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 #include <linux/random.h>
13 #include <linux/tick.h>
14 #include <linux/workqueue.h>
15
16 /*
17  * Called after updating RLIMIT_CPU to run cpu timer and update
18  * tsk->signal->cputime_expires expiration cache if necessary. Needs
19  * siglock protection since other code may update expiration cache as
20  * well.
21  */
22 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
23 {
24         cputime_t cputime = secs_to_cputime(rlim_new);
25
26         spin_lock_irq(&task->sighand->siglock);
27         set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
28         spin_unlock_irq(&task->sighand->siglock);
29 }
30
31 static int check_clock(const clockid_t which_clock)
32 {
33         int error = 0;
34         struct task_struct *p;
35         const pid_t pid = CPUCLOCK_PID(which_clock);
36
37         if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
38                 return -EINVAL;
39
40         if (pid == 0)
41                 return 0;
42
43         rcu_read_lock();
44         p = find_task_by_vpid(pid);
45         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
46                    same_thread_group(p, current) : has_group_leader_pid(p))) {
47                 error = -EINVAL;
48         }
49         rcu_read_unlock();
50
51         return error;
52 }
53
54 static inline unsigned long long
55 timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
56 {
57         unsigned long long ret;
58
59         ret = 0;                /* high half always zero when .cpu used */
60         if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
61                 ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
62         } else {
63                 ret = cputime_to_expires(timespec_to_cputime(tp));
64         }
65         return ret;
66 }
67
68 static void sample_to_timespec(const clockid_t which_clock,
69                                unsigned long long expires,
70                                struct timespec *tp)
71 {
72         if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
73                 *tp = ns_to_timespec(expires);
74         else
75                 cputime_to_timespec((__force cputime_t)expires, tp);
76 }
77
78 /*
79  * Update expiry time from increment, and increase overrun count,
80  * given the current clock sample.
81  */
82 static void bump_cpu_timer(struct k_itimer *timer,
83                            unsigned long long now)
84 {
85         int i;
86         unsigned long long delta, incr;
87
88         if (timer->it.cpu.incr == 0)
89                 return;
90
91         if (now < timer->it.cpu.expires)
92                 return;
93
94         incr = timer->it.cpu.incr;
95         delta = now + incr - timer->it.cpu.expires;
96
97         /* Don't use (incr*2 < delta), incr*2 might overflow. */
98         for (i = 0; incr < delta - incr; i++)
99                 incr = incr << 1;
100
101         for (; i >= 0; incr >>= 1, i--) {
102                 if (delta < incr)
103                         continue;
104
105                 timer->it.cpu.expires += incr;
106                 timer->it_overrun += 1 << i;
107                 delta -= incr;
108         }
109 }
110
111 /**
112  * task_cputime_zero - Check a task_cputime struct for all zero fields.
113  *
114  * @cputime:    The struct to compare.
115  *
116  * Checks @cputime to see if all fields are zero.  Returns true if all fields
117  * are zero, false if any field is nonzero.
118  */
119 static inline int task_cputime_zero(const struct task_cputime *cputime)
120 {
121         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
122                 return 1;
123         return 0;
124 }
125
126 static inline unsigned long long prof_ticks(struct task_struct *p)
127 {
128         cputime_t utime, stime;
129
130         task_cputime(p, &utime, &stime);
131
132         return cputime_to_expires(utime + stime);
133 }
134 static inline unsigned long long virt_ticks(struct task_struct *p)
135 {
136         cputime_t utime;
137
138         task_cputime(p, &utime, NULL);
139
140         return cputime_to_expires(utime);
141 }
142
143 static int
144 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
145 {
146         int error = check_clock(which_clock);
147         if (!error) {
148                 tp->tv_sec = 0;
149                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
150                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
151                         /*
152                          * If sched_clock is using a cycle counter, we
153                          * don't have any idea of its true resolution
154                          * exported, but it is much more than 1s/HZ.
155                          */
156                         tp->tv_nsec = 1;
157                 }
158         }
159         return error;
160 }
161
162 static int
163 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
164 {
165         /*
166          * You can never reset a CPU clock, but we check for other errors
167          * in the call before failing with EPERM.
168          */
169         int error = check_clock(which_clock);
170         if (error == 0) {
171                 error = -EPERM;
172         }
173         return error;
174 }
175
176
177 /*
178  * Sample a per-thread clock for the given task.
179  */
180 static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
181                             unsigned long long *sample)
182 {
183         switch (CPUCLOCK_WHICH(which_clock)) {
184         default:
185                 return -EINVAL;
186         case CPUCLOCK_PROF:
187                 *sample = prof_ticks(p);
188                 break;
189         case CPUCLOCK_VIRT:
190                 *sample = virt_ticks(p);
191                 break;
192         case CPUCLOCK_SCHED:
193                 *sample = task_sched_runtime(p);
194                 break;
195         }
196         return 0;
197 }
198
199 static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
200 {
201         if (b->utime > a->utime)
202                 a->utime = b->utime;
203
204         if (b->stime > a->stime)
205                 a->stime = b->stime;
206
207         if (b->sum_exec_runtime > a->sum_exec_runtime)
208                 a->sum_exec_runtime = b->sum_exec_runtime;
209 }
210
211 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
212 {
213         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
214         struct task_cputime sum;
215         unsigned long flags;
216
217         if (!cputimer->running) {
218                 /*
219                  * The POSIX timer interface allows for absolute time expiry
220                  * values through the TIMER_ABSTIME flag, therefore we have
221                  * to synchronize the timer to the clock every time we start
222                  * it.
223                  */
224                 thread_group_cputime(tsk, &sum);
225                 raw_spin_lock_irqsave(&cputimer->lock, flags);
226                 cputimer->running = 1;
227                 update_gt_cputime(&cputimer->cputime, &sum);
228         } else
229                 raw_spin_lock_irqsave(&cputimer->lock, flags);
230         *times = cputimer->cputime;
231         raw_spin_unlock_irqrestore(&cputimer->lock, flags);
232 }
233
234 /*
235  * Sample a process (thread group) clock for the given group_leader task.
236  * Must be called with task sighand lock held for safe while_each_thread()
237  * traversal.
238  */
239 static int cpu_clock_sample_group(const clockid_t which_clock,
240                                   struct task_struct *p,
241                                   unsigned long long *sample)
242 {
243         struct task_cputime cputime;
244
245         switch (CPUCLOCK_WHICH(which_clock)) {
246         default:
247                 return -EINVAL;
248         case CPUCLOCK_PROF:
249                 thread_group_cputime(p, &cputime);
250                 *sample = cputime_to_expires(cputime.utime + cputime.stime);
251                 break;
252         case CPUCLOCK_VIRT:
253                 thread_group_cputime(p, &cputime);
254                 *sample = cputime_to_expires(cputime.utime);
255                 break;
256         case CPUCLOCK_SCHED:
257                 thread_group_cputime(p, &cputime);
258                 *sample = cputime.sum_exec_runtime;
259                 break;
260         }
261         return 0;
262 }
263
264 static int posix_cpu_clock_get_task(struct task_struct *tsk,
265                                     const clockid_t which_clock,
266                                     struct timespec *tp)
267 {
268         int err = -EINVAL;
269         unsigned long long rtn;
270
271         if (CPUCLOCK_PERTHREAD(which_clock)) {
272                 if (same_thread_group(tsk, current))
273                         err = cpu_clock_sample(which_clock, tsk, &rtn);
274         } else {
275                 unsigned long flags;
276                 struct sighand_struct *sighand;
277
278                 /*
279                  * while_each_thread() is not yet entirely RCU safe,
280                  * keep locking the group while sampling process
281                  * clock for now.
282                  */
283                 sighand = lock_task_sighand(tsk, &flags);
284                 if (!sighand)
285                         return err;
286
287                 if (tsk == current || thread_group_leader(tsk))
288                         err = cpu_clock_sample_group(which_clock, tsk, &rtn);
289
290                 unlock_task_sighand(tsk, &flags);
291         }
292
293         if (!err)
294                 sample_to_timespec(which_clock, rtn, tp);
295
296         return err;
297 }
298
299
300 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
301 {
302         const pid_t pid = CPUCLOCK_PID(which_clock);
303         int err = -EINVAL;
304
305         if (pid == 0) {
306                 /*
307                  * Special case constant value for our own clocks.
308                  * We don't have to do any lookup to find ourselves.
309                  */
310                 err = posix_cpu_clock_get_task(current, which_clock, tp);
311         } else {
312                 /*
313                  * Find the given PID, and validate that the caller
314                  * should be able to see it.
315                  */
316                 struct task_struct *p;
317                 rcu_read_lock();
318                 p = find_task_by_vpid(pid);
319                 if (p)
320                         err = posix_cpu_clock_get_task(p, which_clock, tp);
321                 rcu_read_unlock();
322         }
323
324         return err;
325 }
326
327
328 /*
329  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
330  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
331  * new timer already all-zeros initialized.
332  */
333 static int posix_cpu_timer_create(struct k_itimer *new_timer)
334 {
335         int ret = 0;
336         const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
337         struct task_struct *p;
338
339         if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
340                 return -EINVAL;
341
342         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
343
344         rcu_read_lock();
345         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
346                 if (pid == 0) {
347                         p = current;
348                 } else {
349                         p = find_task_by_vpid(pid);
350                         if (p && !same_thread_group(p, current))
351                                 p = NULL;
352                 }
353         } else {
354                 if (pid == 0) {
355                         p = current->group_leader;
356                 } else {
357                         p = find_task_by_vpid(pid);
358                         if (p && !has_group_leader_pid(p))
359                                 p = NULL;
360                 }
361         }
362         new_timer->it.cpu.task = p;
363         if (p) {
364                 get_task_struct(p);
365         } else {
366                 ret = -EINVAL;
367         }
368         rcu_read_unlock();
369
370         return ret;
371 }
372
373 /*
374  * Clean up a CPU-clock timer that is about to be destroyed.
375  * This is called from timer deletion with the timer already locked.
376  * If we return TIMER_RETRY, it's necessary to release the timer's lock
377  * and try again.  (This happens when the timer is in the middle of firing.)
378  */
379 static int posix_cpu_timer_del(struct k_itimer *timer)
380 {
381         int ret = 0;
382         unsigned long flags;
383         struct sighand_struct *sighand;
384         struct task_struct *p = timer->it.cpu.task;
385
386         WARN_ON_ONCE(p == NULL);
387
388         /*
389          * Protect against sighand release/switch in exit/exec and process/
390          * thread timer list entry concurrent read/writes.
391          */
392         sighand = lock_task_sighand(p, &flags);
393         if (unlikely(sighand == NULL)) {
394                 /*
395                  * We raced with the reaping of the task.
396                  * The deletion should have cleared us off the list.
397                  */
398                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
399         } else {
400                 if (timer->it.cpu.firing)
401                         ret = TIMER_RETRY;
402                 else
403                         list_del(&timer->it.cpu.entry);
404
405                 unlock_task_sighand(p, &flags);
406         }
407
408         if (!ret)
409                 put_task_struct(p);
410
411         return ret;
412 }
413
414 static void cleanup_timers_list(struct list_head *head)
415 {
416         struct cpu_timer_list *timer, *next;
417
418         list_for_each_entry_safe(timer, next, head, entry)
419                 list_del_init(&timer->entry);
420 }
421
422 /*
423  * Clean out CPU timers still ticking when a thread exited.  The task
424  * pointer is cleared, and the expiry time is replaced with the residual
425  * time for later timer_gettime calls to return.
426  * This must be called with the siglock held.
427  */
428 static void cleanup_timers(struct list_head *head)
429 {
430         cleanup_timers_list(head);
431         cleanup_timers_list(++head);
432         cleanup_timers_list(++head);
433 }
434
435 /*
436  * These are both called with the siglock held, when the current thread
437  * is being reaped.  When the final (leader) thread in the group is reaped,
438  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
439  */
440 void posix_cpu_timers_exit(struct task_struct *tsk)
441 {
442         add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
443                                                 sizeof(unsigned long long));
444         cleanup_timers(tsk->cpu_timers);
445
446 }
447 void posix_cpu_timers_exit_group(struct task_struct *tsk)
448 {
449         cleanup_timers(tsk->signal->cpu_timers);
450 }
451
452 static inline int expires_gt(cputime_t expires, cputime_t new_exp)
453 {
454         return expires == 0 || expires > new_exp;
455 }
456
457 /*
458  * Insert the timer on the appropriate list before any timers that
459  * expire later.  This must be called with the sighand lock held.
460  */
461 static void arm_timer(struct k_itimer *timer)
462 {
463         struct task_struct *p = timer->it.cpu.task;
464         struct list_head *head, *listpos;
465         struct task_cputime *cputime_expires;
466         struct cpu_timer_list *const nt = &timer->it.cpu;
467         struct cpu_timer_list *next;
468
469         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
470                 head = p->cpu_timers;
471                 cputime_expires = &p->cputime_expires;
472         } else {
473                 head = p->signal->cpu_timers;
474                 cputime_expires = &p->signal->cputime_expires;
475         }
476         head += CPUCLOCK_WHICH(timer->it_clock);
477
478         listpos = head;
479         list_for_each_entry(next, head, entry) {
480                 if (nt->expires < next->expires)
481                         break;
482                 listpos = &next->entry;
483         }
484         list_add(&nt->entry, listpos);
485
486         if (listpos == head) {
487                 unsigned long long exp = nt->expires;
488
489                 /*
490                  * We are the new earliest-expiring POSIX 1.b timer, hence
491                  * need to update expiration cache. Take into account that
492                  * for process timers we share expiration cache with itimers
493                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
494                  */
495
496                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
497                 case CPUCLOCK_PROF:
498                         if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
499                                 cputime_expires->prof_exp = expires_to_cputime(exp);
500                         break;
501                 case CPUCLOCK_VIRT:
502                         if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
503                                 cputime_expires->virt_exp = expires_to_cputime(exp);
504                         break;
505                 case CPUCLOCK_SCHED:
506                         if (cputime_expires->sched_exp == 0 ||
507                             cputime_expires->sched_exp > exp)
508                                 cputime_expires->sched_exp = exp;
509                         break;
510                 }
511         }
512 }
513
514 /*
515  * The timer is locked, fire it and arrange for its reload.
516  */
517 static void cpu_timer_fire(struct k_itimer *timer)
518 {
519         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
520                 /*
521                  * User don't want any signal.
522                  */
523                 timer->it.cpu.expires = 0;
524         } else if (unlikely(timer->sigq == NULL)) {
525                 /*
526                  * This a special case for clock_nanosleep,
527                  * not a normal timer from sys_timer_create.
528                  */
529                 wake_up_process(timer->it_process);
530                 timer->it.cpu.expires = 0;
531         } else if (timer->it.cpu.incr == 0) {
532                 /*
533                  * One-shot timer.  Clear it as soon as it's fired.
534                  */
535                 posix_timer_event(timer, 0);
536                 timer->it.cpu.expires = 0;
537         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
538                 /*
539                  * The signal did not get queued because the signal
540                  * was ignored, so we won't get any callback to
541                  * reload the timer.  But we need to keep it
542                  * ticking in case the signal is deliverable next time.
543                  */
544                 posix_cpu_timer_schedule(timer);
545         }
546 }
547
548 /*
549  * Sample a process (thread group) timer for the given group_leader task.
550  * Must be called with task sighand lock held for safe while_each_thread()
551  * traversal.
552  */
553 static int cpu_timer_sample_group(const clockid_t which_clock,
554                                   struct task_struct *p,
555                                   unsigned long long *sample)
556 {
557         struct task_cputime cputime;
558
559         thread_group_cputimer(p, &cputime);
560         switch (CPUCLOCK_WHICH(which_clock)) {
561         default:
562                 return -EINVAL;
563         case CPUCLOCK_PROF:
564                 *sample = cputime_to_expires(cputime.utime + cputime.stime);
565                 break;
566         case CPUCLOCK_VIRT:
567                 *sample = cputime_to_expires(cputime.utime);
568                 break;
569         case CPUCLOCK_SCHED:
570                 *sample = cputime.sum_exec_runtime + task_delta_exec(p);
571                 break;
572         }
573         return 0;
574 }
575
576 #ifdef CONFIG_NO_HZ_FULL
577 static void nohz_kick_work_fn(struct work_struct *work)
578 {
579         tick_nohz_full_kick_all();
580 }
581
582 static DECLARE_WORK(nohz_kick_work, nohz_kick_work_fn);
583
584 /*
585  * We need the IPIs to be sent from sane process context.
586  * The posix cpu timers are always set with irqs disabled.
587  */
588 static void posix_cpu_timer_kick_nohz(void)
589 {
590         if (context_tracking_is_enabled())
591                 schedule_work(&nohz_kick_work);
592 }
593
594 bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk)
595 {
596         if (!task_cputime_zero(&tsk->cputime_expires))
597                 return false;
598
599         if (tsk->signal->cputimer.running)
600                 return false;
601
602         return true;
603 }
604 #else
605 static inline void posix_cpu_timer_kick_nohz(void) { }
606 #endif
607
608 /*
609  * Guts of sys_timer_settime for CPU timers.
610  * This is called with the timer locked and interrupts disabled.
611  * If we return TIMER_RETRY, it's necessary to release the timer's lock
612  * and try again.  (This happens when the timer is in the middle of firing.)
613  */
614 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
615                                struct itimerspec *new, struct itimerspec *old)
616 {
617         unsigned long flags;
618         struct sighand_struct *sighand;
619         struct task_struct *p = timer->it.cpu.task;
620         unsigned long long old_expires, new_expires, old_incr, val;
621         int ret;
622
623         WARN_ON_ONCE(p == NULL);
624
625         new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
626
627         /*
628          * Protect against sighand release/switch in exit/exec and p->cpu_timers
629          * and p->signal->cpu_timers read/write in arm_timer()
630          */
631         sighand = lock_task_sighand(p, &flags);
632         /*
633          * If p has just been reaped, we can no
634          * longer get any information about it at all.
635          */
636         if (unlikely(sighand == NULL)) {
637                 return -ESRCH;
638         }
639
640         /*
641          * Disarm any old timer after extracting its expiry time.
642          */
643         WARN_ON_ONCE(!irqs_disabled());
644
645         ret = 0;
646         old_incr = timer->it.cpu.incr;
647         old_expires = timer->it.cpu.expires;
648         if (unlikely(timer->it.cpu.firing)) {
649                 timer->it.cpu.firing = -1;
650                 ret = TIMER_RETRY;
651         } else
652                 list_del_init(&timer->it.cpu.entry);
653
654         /*
655          * We need to sample the current value to convert the new
656          * value from to relative and absolute, and to convert the
657          * old value from absolute to relative.  To set a process
658          * timer, we need a sample to balance the thread expiry
659          * times (in arm_timer).  With an absolute time, we must
660          * check if it's already passed.  In short, we need a sample.
661          */
662         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
663                 cpu_clock_sample(timer->it_clock, p, &val);
664         } else {
665                 cpu_timer_sample_group(timer->it_clock, p, &val);
666         }
667
668         if (old) {
669                 if (old_expires == 0) {
670                         old->it_value.tv_sec = 0;
671                         old->it_value.tv_nsec = 0;
672                 } else {
673                         /*
674                          * Update the timer in case it has
675                          * overrun already.  If it has,
676                          * we'll report it as having overrun
677                          * and with the next reloaded timer
678                          * already ticking, though we are
679                          * swallowing that pending
680                          * notification here to install the
681                          * new setting.
682                          */
683                         bump_cpu_timer(timer, val);
684                         if (val < timer->it.cpu.expires) {
685                                 old_expires = timer->it.cpu.expires - val;
686                                 sample_to_timespec(timer->it_clock,
687                                                    old_expires,
688                                                    &old->it_value);
689                         } else {
690                                 old->it_value.tv_nsec = 1;
691                                 old->it_value.tv_sec = 0;
692                         }
693                 }
694         }
695
696         if (unlikely(ret)) {
697                 /*
698                  * We are colliding with the timer actually firing.
699                  * Punt after filling in the timer's old value, and
700                  * disable this firing since we are already reporting
701                  * it as an overrun (thanks to bump_cpu_timer above).
702                  */
703                 unlock_task_sighand(p, &flags);
704                 goto out;
705         }
706
707         if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
708                 new_expires += val;
709         }
710
711         /*
712          * Install the new expiry time (or zero).
713          * For a timer with no notification action, we don't actually
714          * arm the timer (we'll just fake it for timer_gettime).
715          */
716         timer->it.cpu.expires = new_expires;
717         if (new_expires != 0 && val < new_expires) {
718                 arm_timer(timer);
719         }
720
721         unlock_task_sighand(p, &flags);
722         /*
723          * Install the new reload setting, and
724          * set up the signal and overrun bookkeeping.
725          */
726         timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
727                                                 &new->it_interval);
728
729         /*
730          * This acts as a modification timestamp for the timer,
731          * so any automatic reload attempt will punt on seeing
732          * that we have reset the timer manually.
733          */
734         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
735                 ~REQUEUE_PENDING;
736         timer->it_overrun_last = 0;
737         timer->it_overrun = -1;
738
739         if (new_expires != 0 && !(val < new_expires)) {
740                 /*
741                  * The designated time already passed, so we notify
742                  * immediately, even if the thread never runs to
743                  * accumulate more time on this clock.
744                  */
745                 cpu_timer_fire(timer);
746         }
747
748         ret = 0;
749  out:
750         if (old) {
751                 sample_to_timespec(timer->it_clock,
752                                    old_incr, &old->it_interval);
753         }
754         if (!ret)
755                 posix_cpu_timer_kick_nohz();
756         return ret;
757 }
758
759 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
760 {
761         unsigned long long now;
762         struct task_struct *p = timer->it.cpu.task;
763
764         WARN_ON_ONCE(p == NULL);
765
766         /*
767          * Easy part: convert the reload time.
768          */
769         sample_to_timespec(timer->it_clock,
770                            timer->it.cpu.incr, &itp->it_interval);
771
772         if (timer->it.cpu.expires == 0) {       /* Timer not armed at all.  */
773                 itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
774                 return;
775         }
776
777         /*
778          * Sample the clock to take the difference with the expiry time.
779          */
780         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
781                 cpu_clock_sample(timer->it_clock, p, &now);
782         } else {
783                 struct sighand_struct *sighand;
784                 unsigned long flags;
785
786                 /*
787                  * Protect against sighand release/switch in exit/exec and
788                  * also make timer sampling safe if it ends up calling
789                  * thread_group_cputime().
790                  */
791                 sighand = lock_task_sighand(p, &flags);
792                 if (unlikely(sighand == NULL)) {
793                         /*
794                          * The process has been reaped.
795                          * We can't even collect a sample any more.
796                          * Call the timer disarmed, nothing else to do.
797                          */
798                         timer->it.cpu.expires = 0;
799                         sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
800                                            &itp->it_value);
801                 } else {
802                         cpu_timer_sample_group(timer->it_clock, p, &now);
803                         unlock_task_sighand(p, &flags);
804                 }
805         }
806
807         if (now < timer->it.cpu.expires) {
808                 sample_to_timespec(timer->it_clock,
809                                    timer->it.cpu.expires - now,
810                                    &itp->it_value);
811         } else {
812                 /*
813                  * The timer should have expired already, but the firing
814                  * hasn't taken place yet.  Say it's just about to expire.
815                  */
816                 itp->it_value.tv_nsec = 1;
817                 itp->it_value.tv_sec = 0;
818         }
819 }
820
821 static unsigned long long
822 check_timers_list(struct list_head *timers,
823                   struct list_head *firing,
824                   unsigned long long curr)
825 {
826         int maxfire = 20;
827
828         while (!list_empty(timers)) {
829                 struct cpu_timer_list *t;
830
831                 t = list_first_entry(timers, struct cpu_timer_list, entry);
832
833                 if (!--maxfire || curr < t->expires)
834                         return t->expires;
835
836                 t->firing = 1;
837                 list_move_tail(&t->entry, firing);
838         }
839
840         return 0;
841 }
842
843 /*
844  * Check for any per-thread CPU timers that have fired and move them off
845  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
846  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
847  */
848 static void check_thread_timers(struct task_struct *tsk,
849                                 struct list_head *firing)
850 {
851         struct list_head *timers = tsk->cpu_timers;
852         struct signal_struct *const sig = tsk->signal;
853         struct task_cputime *tsk_expires = &tsk->cputime_expires;
854         unsigned long long expires;
855         unsigned long soft;
856
857         expires = check_timers_list(timers, firing, prof_ticks(tsk));
858         tsk_expires->prof_exp = expires_to_cputime(expires);
859
860         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
861         tsk_expires->virt_exp = expires_to_cputime(expires);
862
863         tsk_expires->sched_exp = check_timers_list(++timers, firing,
864                                                    tsk->se.sum_exec_runtime);
865
866         /*
867          * Check for the special case thread timers.
868          */
869         soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
870         if (soft != RLIM_INFINITY) {
871                 unsigned long hard =
872                         ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
873
874                 if (hard != RLIM_INFINITY &&
875                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
876                         /*
877                          * At the hard limit, we just die.
878                          * No need to calculate anything else now.
879                          */
880                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
881                         return;
882                 }
883                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
884                         /*
885                          * At the soft limit, send a SIGXCPU every second.
886                          */
887                         if (soft < hard) {
888                                 soft += USEC_PER_SEC;
889                                 sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
890                         }
891                         printk(KERN_INFO
892                                 "RT Watchdog Timeout: %s[%d]\n",
893                                 tsk->comm, task_pid_nr(tsk));
894                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
895                 }
896         }
897 }
898
899 static void stop_process_timers(struct signal_struct *sig)
900 {
901         struct thread_group_cputimer *cputimer = &sig->cputimer;
902         unsigned long flags;
903
904         raw_spin_lock_irqsave(&cputimer->lock, flags);
905         cputimer->running = 0;
906         raw_spin_unlock_irqrestore(&cputimer->lock, flags);
907 }
908
909 static u32 onecputick;
910
911 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
912                              unsigned long long *expires,
913                              unsigned long long cur_time, int signo)
914 {
915         if (!it->expires)
916                 return;
917
918         if (cur_time >= it->expires) {
919                 if (it->incr) {
920                         it->expires += it->incr;
921                         it->error += it->incr_error;
922                         if (it->error >= onecputick) {
923                                 it->expires -= cputime_one_jiffy;
924                                 it->error -= onecputick;
925                         }
926                 } else {
927                         it->expires = 0;
928                 }
929
930                 trace_itimer_expire(signo == SIGPROF ?
931                                     ITIMER_PROF : ITIMER_VIRTUAL,
932                                     tsk->signal->leader_pid, cur_time);
933                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
934         }
935
936         if (it->expires && (!*expires || it->expires < *expires)) {
937                 *expires = it->expires;
938         }
939 }
940
941 /*
942  * Check for any per-thread CPU timers that have fired and move them
943  * off the tsk->*_timers list onto the firing list.  Per-thread timers
944  * have already been taken off.
945  */
946 static void check_process_timers(struct task_struct *tsk,
947                                  struct list_head *firing)
948 {
949         struct signal_struct *const sig = tsk->signal;
950         unsigned long long utime, ptime, virt_expires, prof_expires;
951         unsigned long long sum_sched_runtime, sched_expires;
952         struct list_head *timers = sig->cpu_timers;
953         struct task_cputime cputime;
954         unsigned long soft;
955
956         /*
957          * Collect the current process totals.
958          */
959         thread_group_cputimer(tsk, &cputime);
960         utime = cputime_to_expires(cputime.utime);
961         ptime = utime + cputime_to_expires(cputime.stime);
962         sum_sched_runtime = cputime.sum_exec_runtime;
963
964         prof_expires = check_timers_list(timers, firing, ptime);
965         virt_expires = check_timers_list(++timers, firing, utime);
966         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
967
968         /*
969          * Check for the special case process timers.
970          */
971         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
972                          SIGPROF);
973         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
974                          SIGVTALRM);
975         soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
976         if (soft != RLIM_INFINITY) {
977                 unsigned long psecs = cputime_to_secs(ptime);
978                 unsigned long hard =
979                         ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
980                 cputime_t x;
981                 if (psecs >= hard) {
982                         /*
983                          * At the hard limit, we just die.
984                          * No need to calculate anything else now.
985                          */
986                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
987                         return;
988                 }
989                 if (psecs >= soft) {
990                         /*
991                          * At the soft limit, send a SIGXCPU every second.
992                          */
993                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
994                         if (soft < hard) {
995                                 soft++;
996                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
997                         }
998                 }
999                 x = secs_to_cputime(soft);
1000                 if (!prof_expires || x < prof_expires) {
1001                         prof_expires = x;
1002                 }
1003         }
1004
1005         sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
1006         sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
1007         sig->cputime_expires.sched_exp = sched_expires;
1008         if (task_cputime_zero(&sig->cputime_expires))
1009                 stop_process_timers(sig);
1010 }
1011
1012 /*
1013  * This is called from the signal code (via do_schedule_next_timer)
1014  * when the last timer signal was delivered and we have to reload the timer.
1015  */
1016 void posix_cpu_timer_schedule(struct k_itimer *timer)
1017 {
1018         struct sighand_struct *sighand;
1019         unsigned long flags;
1020         struct task_struct *p = timer->it.cpu.task;
1021         unsigned long long now;
1022
1023         WARN_ON_ONCE(p == NULL);
1024
1025         /*
1026          * Fetch the current sample and update the timer's expiry time.
1027          */
1028         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1029                 cpu_clock_sample(timer->it_clock, p, &now);
1030                 bump_cpu_timer(timer, now);
1031                 if (unlikely(p->exit_state))
1032                         goto out;
1033
1034                 /* Protect timer list r/w in arm_timer() */
1035                 sighand = lock_task_sighand(p, &flags);
1036                 if (!sighand)
1037                         goto out;
1038         } else {
1039                 /*
1040                  * Protect arm_timer() and timer sampling in case of call to
1041                  * thread_group_cputime().
1042                  */
1043                 sighand = lock_task_sighand(p, &flags);
1044                 if (unlikely(sighand == NULL)) {
1045                         /*
1046                          * The process has been reaped.
1047                          * We can't even collect a sample any more.
1048                          */
1049                         timer->it.cpu.expires = 0;
1050                         goto out;
1051                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1052                         unlock_task_sighand(p, &flags);
1053                         /* Optimizations: if the process is dying, no need to rearm */
1054                         goto out;
1055                 }
1056                 cpu_timer_sample_group(timer->it_clock, p, &now);
1057                 bump_cpu_timer(timer, now);
1058                 /* Leave the sighand locked for the call below.  */
1059         }
1060
1061         /*
1062          * Now re-arm for the new expiry time.
1063          */
1064         WARN_ON_ONCE(!irqs_disabled());
1065         arm_timer(timer);
1066         unlock_task_sighand(p, &flags);
1067
1068         /* Kick full dynticks CPUs in case they need to tick on the new timer */
1069         posix_cpu_timer_kick_nohz();
1070 out:
1071         timer->it_overrun_last = timer->it_overrun;
1072         timer->it_overrun = -1;
1073         ++timer->it_requeue_pending;
1074 }
1075
1076 /**
1077  * task_cputime_expired - Compare two task_cputime entities.
1078  *
1079  * @sample:     The task_cputime structure to be checked for expiration.
1080  * @expires:    Expiration times, against which @sample will be checked.
1081  *
1082  * Checks @sample against @expires to see if any field of @sample has expired.
1083  * Returns true if any field of the former is greater than the corresponding
1084  * field of the latter if the latter field is set.  Otherwise returns false.
1085  */
1086 static inline int task_cputime_expired(const struct task_cputime *sample,
1087                                         const struct task_cputime *expires)
1088 {
1089         if (expires->utime && sample->utime >= expires->utime)
1090                 return 1;
1091         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1092                 return 1;
1093         if (expires->sum_exec_runtime != 0 &&
1094             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1095                 return 1;
1096         return 0;
1097 }
1098
1099 /**
1100  * fastpath_timer_check - POSIX CPU timers fast path.
1101  *
1102  * @tsk:        The task (thread) being checked.
1103  *
1104  * Check the task and thread group timers.  If both are zero (there are no
1105  * timers set) return false.  Otherwise snapshot the task and thread group
1106  * timers and compare them with the corresponding expiration times.  Return
1107  * true if a timer has expired, else return false.
1108  */
1109 static inline int fastpath_timer_check(struct task_struct *tsk)
1110 {
1111         struct signal_struct *sig;
1112         cputime_t utime, stime;
1113
1114         task_cputime(tsk, &utime, &stime);
1115
1116         if (!task_cputime_zero(&tsk->cputime_expires)) {
1117                 struct task_cputime task_sample = {
1118                         .utime = utime,
1119                         .stime = stime,
1120                         .sum_exec_runtime = tsk->se.sum_exec_runtime
1121                 };
1122
1123                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1124                         return 1;
1125         }
1126
1127         sig = tsk->signal;
1128         if (sig->cputimer.running) {
1129                 struct task_cputime group_sample;
1130
1131                 raw_spin_lock(&sig->cputimer.lock);
1132                 group_sample = sig->cputimer.cputime;
1133                 raw_spin_unlock(&sig->cputimer.lock);
1134
1135                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1136                         return 1;
1137         }
1138
1139         return 0;
1140 }
1141
1142 /*
1143  * This is called from the timer interrupt handler.  The irq handler has
1144  * already updated our counts.  We need to check if any timers fire now.
1145  * Interrupts are disabled.
1146  */
1147 void run_posix_cpu_timers(struct task_struct *tsk)
1148 {
1149         LIST_HEAD(firing);
1150         struct k_itimer *timer, *next;
1151         unsigned long flags;
1152
1153         WARN_ON_ONCE(!irqs_disabled());
1154
1155         /*
1156          * The fast path checks that there are no expired thread or thread
1157          * group timers.  If that's so, just return.
1158          */
1159         if (!fastpath_timer_check(tsk))
1160                 return;
1161
1162         if (!lock_task_sighand(tsk, &flags))
1163                 return;
1164         /*
1165          * Here we take off tsk->signal->cpu_timers[N] and
1166          * tsk->cpu_timers[N] all the timers that are firing, and
1167          * put them on the firing list.
1168          */
1169         check_thread_timers(tsk, &firing);
1170         /*
1171          * If there are any active process wide timers (POSIX 1.b, itimers,
1172          * RLIMIT_CPU) cputimer must be running.
1173          */
1174         if (tsk->signal->cputimer.running)
1175                 check_process_timers(tsk, &firing);
1176
1177         /*
1178          * We must release these locks before taking any timer's lock.
1179          * There is a potential race with timer deletion here, as the
1180          * siglock now protects our private firing list.  We have set
1181          * the firing flag in each timer, so that a deletion attempt
1182          * that gets the timer lock before we do will give it up and
1183          * spin until we've taken care of that timer below.
1184          */
1185         unlock_task_sighand(tsk, &flags);
1186
1187         /*
1188          * Now that all the timers on our list have the firing flag,
1189          * no one will touch their list entries but us.  We'll take
1190          * each timer's lock before clearing its firing flag, so no
1191          * timer call will interfere.
1192          */
1193         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1194                 int cpu_firing;
1195
1196                 spin_lock(&timer->it_lock);
1197                 list_del_init(&timer->it.cpu.entry);
1198                 cpu_firing = timer->it.cpu.firing;
1199                 timer->it.cpu.firing = 0;
1200                 /*
1201                  * The firing flag is -1 if we collided with a reset
1202                  * of the timer, which already reported this
1203                  * almost-firing as an overrun.  So don't generate an event.
1204                  */
1205                 if (likely(cpu_firing >= 0))
1206                         cpu_timer_fire(timer);
1207                 spin_unlock(&timer->it_lock);
1208         }
1209 }
1210
1211 /*
1212  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1213  * The tsk->sighand->siglock must be held by the caller.
1214  */
1215 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1216                            cputime_t *newval, cputime_t *oldval)
1217 {
1218         unsigned long long now;
1219
1220         WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
1221         cpu_timer_sample_group(clock_idx, tsk, &now);
1222
1223         if (oldval) {
1224                 /*
1225                  * We are setting itimer. The *oldval is absolute and we update
1226                  * it to be relative, *newval argument is relative and we update
1227                  * it to be absolute.
1228                  */
1229                 if (*oldval) {
1230                         if (*oldval <= now) {
1231                                 /* Just about to fire. */
1232                                 *oldval = cputime_one_jiffy;
1233                         } else {
1234                                 *oldval -= now;
1235                         }
1236                 }
1237
1238                 if (!*newval)
1239                         goto out;
1240                 *newval += now;
1241         }
1242
1243         /*
1244          * Update expiration cache if we are the earliest timer, or eventually
1245          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1246          */
1247         switch (clock_idx) {
1248         case CPUCLOCK_PROF:
1249                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1250                         tsk->signal->cputime_expires.prof_exp = *newval;
1251                 break;
1252         case CPUCLOCK_VIRT:
1253                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1254                         tsk->signal->cputime_expires.virt_exp = *newval;
1255                 break;
1256         }
1257 out:
1258         posix_cpu_timer_kick_nohz();
1259 }
1260
1261 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1262                             struct timespec *rqtp, struct itimerspec *it)
1263 {
1264         struct k_itimer timer;
1265         int error;
1266
1267         /*
1268          * Set up a temporary timer and then wait for it to go off.
1269          */
1270         memset(&timer, 0, sizeof timer);
1271         spin_lock_init(&timer.it_lock);
1272         timer.it_clock = which_clock;
1273         timer.it_overrun = -1;
1274         error = posix_cpu_timer_create(&timer);
1275         timer.it_process = current;
1276         if (!error) {
1277                 static struct itimerspec zero_it;
1278
1279                 memset(it, 0, sizeof *it);
1280                 it->it_value = *rqtp;
1281
1282                 spin_lock_irq(&timer.it_lock);
1283                 error = posix_cpu_timer_set(&timer, flags, it, NULL);
1284                 if (error) {
1285                         spin_unlock_irq(&timer.it_lock);
1286                         return error;
1287                 }
1288
1289                 while (!signal_pending(current)) {
1290                         if (timer.it.cpu.expires == 0) {
1291                                 /*
1292                                  * Our timer fired and was reset, below
1293                                  * deletion can not fail.
1294                                  */
1295                                 posix_cpu_timer_del(&timer);
1296                                 spin_unlock_irq(&timer.it_lock);
1297                                 return 0;
1298                         }
1299
1300                         /*
1301                          * Block until cpu_timer_fire (or a signal) wakes us.
1302                          */
1303                         __set_current_state(TASK_INTERRUPTIBLE);
1304                         spin_unlock_irq(&timer.it_lock);
1305                         schedule();
1306                         spin_lock_irq(&timer.it_lock);
1307                 }
1308
1309                 /*
1310                  * We were interrupted by a signal.
1311                  */
1312                 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
1313                 error = posix_cpu_timer_set(&timer, 0, &zero_it, it);
1314                 if (!error) {
1315                         /*
1316                          * Timer is now unarmed, deletion can not fail.
1317                          */
1318                         posix_cpu_timer_del(&timer);
1319                 }
1320                 spin_unlock_irq(&timer.it_lock);
1321
1322                 while (error == TIMER_RETRY) {
1323                         /*
1324                          * We need to handle case when timer was or is in the
1325                          * middle of firing. In other cases we already freed
1326                          * resources.
1327                          */
1328                         spin_lock_irq(&timer.it_lock);
1329                         error = posix_cpu_timer_del(&timer);
1330                         spin_unlock_irq(&timer.it_lock);
1331                 }
1332
1333                 if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
1334                         /*
1335                          * It actually did fire already.
1336                          */
1337                         return 0;
1338                 }
1339
1340                 error = -ERESTART_RESTARTBLOCK;
1341         }
1342
1343         return error;
1344 }
1345
1346 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1347
1348 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1349                             struct timespec *rqtp, struct timespec __user *rmtp)
1350 {
1351         struct restart_block *restart_block =
1352                 &current_thread_info()->restart_block;
1353         struct itimerspec it;
1354         int error;
1355
1356         /*
1357          * Diagnose required errors first.
1358          */
1359         if (CPUCLOCK_PERTHREAD(which_clock) &&
1360             (CPUCLOCK_PID(which_clock) == 0 ||
1361              CPUCLOCK_PID(which_clock) == current->pid))
1362                 return -EINVAL;
1363
1364         error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
1365
1366         if (error == -ERESTART_RESTARTBLOCK) {
1367
1368                 if (flags & TIMER_ABSTIME)
1369                         return -ERESTARTNOHAND;
1370                 /*
1371                  * Report back to the user the time still remaining.
1372                  */
1373                 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1374                         return -EFAULT;
1375
1376                 restart_block->fn = posix_cpu_nsleep_restart;
1377                 restart_block->nanosleep.clockid = which_clock;
1378                 restart_block->nanosleep.rmtp = rmtp;
1379                 restart_block->nanosleep.expires = timespec_to_ns(rqtp);
1380         }
1381         return error;
1382 }
1383
1384 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1385 {
1386         clockid_t which_clock = restart_block->nanosleep.clockid;
1387         struct timespec t;
1388         struct itimerspec it;
1389         int error;
1390
1391         t = ns_to_timespec(restart_block->nanosleep.expires);
1392
1393         error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
1394
1395         if (error == -ERESTART_RESTARTBLOCK) {
1396                 struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
1397                 /*
1398                  * Report back to the user the time still remaining.
1399                  */
1400                 if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
1401                         return -EFAULT;
1402
1403                 restart_block->nanosleep.expires = timespec_to_ns(&t);
1404         }
1405         return error;
1406
1407 }
1408
1409 #define PROCESS_CLOCK   MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1410 #define THREAD_CLOCK    MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1411
1412 static int process_cpu_clock_getres(const clockid_t which_clock,
1413                                     struct timespec *tp)
1414 {
1415         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1416 }
1417 static int process_cpu_clock_get(const clockid_t which_clock,
1418                                  struct timespec *tp)
1419 {
1420         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1421 }
1422 static int process_cpu_timer_create(struct k_itimer *timer)
1423 {
1424         timer->it_clock = PROCESS_CLOCK;
1425         return posix_cpu_timer_create(timer);
1426 }
1427 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1428                               struct timespec *rqtp,
1429                               struct timespec __user *rmtp)
1430 {
1431         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
1432 }
1433 static long process_cpu_nsleep_restart(struct restart_block *restart_block)
1434 {
1435         return -EINVAL;
1436 }
1437 static int thread_cpu_clock_getres(const clockid_t which_clock,
1438                                    struct timespec *tp)
1439 {
1440         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1441 }
1442 static int thread_cpu_clock_get(const clockid_t which_clock,
1443                                 struct timespec *tp)
1444 {
1445         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1446 }
1447 static int thread_cpu_timer_create(struct k_itimer *timer)
1448 {
1449         timer->it_clock = THREAD_CLOCK;
1450         return posix_cpu_timer_create(timer);
1451 }
1452
1453 struct k_clock clock_posix_cpu = {
1454         .clock_getres   = posix_cpu_clock_getres,
1455         .clock_set      = posix_cpu_clock_set,
1456         .clock_get      = posix_cpu_clock_get,
1457         .timer_create   = posix_cpu_timer_create,
1458         .nsleep         = posix_cpu_nsleep,
1459         .nsleep_restart = posix_cpu_nsleep_restart,
1460         .timer_set      = posix_cpu_timer_set,
1461         .timer_del      = posix_cpu_timer_del,
1462         .timer_get      = posix_cpu_timer_get,
1463 };
1464
1465 static __init int init_posix_cpu_timers(void)
1466 {
1467         struct k_clock process = {
1468                 .clock_getres   = process_cpu_clock_getres,
1469                 .clock_get      = process_cpu_clock_get,
1470                 .timer_create   = process_cpu_timer_create,
1471                 .nsleep         = process_cpu_nsleep,
1472                 .nsleep_restart = process_cpu_nsleep_restart,
1473         };
1474         struct k_clock thread = {
1475                 .clock_getres   = thread_cpu_clock_getres,
1476                 .clock_get      = thread_cpu_clock_get,
1477                 .timer_create   = thread_cpu_timer_create,
1478         };
1479         struct timespec ts;
1480
1481         posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
1482         posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
1483
1484         cputime_to_timespec(cputime_one_jiffy, &ts);
1485         onecputick = ts.tv_nsec;
1486         WARN_ON(ts.tv_sec != 0);
1487
1488         return 0;
1489 }
1490 __initcall(init_posix_cpu_timers);