2 * linux/kernel/posix-timers.c
5 * 2002-10-15 Posix Clocks & timers
6 * by George Anzinger george@mvista.com
8 * Copyright (C) 2002 2003 by MontaVista Software.
10 * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
11 * Copyright (C) 2004 Boris Hu
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or (at
16 * your option) any later version.
18 * This program is distributed in the hope that it will be useful, but
19 * WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 * General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
30 /* These are all the functions necessary to implement
31 * POSIX clocks & timers
34 #include <linux/interrupt.h>
35 #include <linux/slab.h>
36 #include <linux/time.h>
37 #include <linux/mutex.h>
39 #include <asm/uaccess.h>
40 #include <linux/list.h>
41 #include <linux/init.h>
42 #include <linux/compiler.h>
43 #include <linux/hash.h>
44 #include <linux/posix-clock.h>
45 #include <linux/posix-timers.h>
46 #include <linux/syscalls.h>
47 #include <linux/wait.h>
48 #include <linux/workqueue.h>
49 #include <linux/export.h>
50 #include <linux/hashtable.h>
52 #include "timekeeping.h"
55 * Management arrays for POSIX timers. Timers are now kept in static hash table
57 * Timer ids are allocated by local routine, which selects proper hash head by
58 * key, constructed from current->signal address and per signal struct counter.
59 * This keeps timer ids unique per process, but now they can intersect between
64 * Lets keep our timers in a slab cache :-)
66 static struct kmem_cache *posix_timers_cache;
68 static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
69 static DEFINE_SPINLOCK(hash_lock);
72 * we assume that the new SIGEV_THREAD_ID shares no bits with the other
73 * SIGEV values. Here we put out an error if this assumption fails.
75 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
76 ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
77 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
81 * parisc wants ENOTSUP instead of EOPNOTSUPP
84 # define ENANOSLEEP_NOTSUP EOPNOTSUPP
86 # define ENANOSLEEP_NOTSUP ENOTSUP
90 * The timer ID is turned into a timer address by idr_find().
91 * Verifying a valid ID consists of:
93 * a) checking that idr_find() returns other than -1.
94 * b) checking that the timer id matches the one in the timer itself.
95 * c) that the timer owner is in the callers thread group.
99 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
100 * to implement others. This structure defines the various
103 * RESOLUTION: Clock resolution is used to round up timer and interval
104 * times, NOT to report clock times, which are reported with as
105 * much resolution as the system can muster. In some cases this
106 * resolution may depend on the underlying clock hardware and
107 * may not be quantifiable until run time, and only then is the
108 * necessary code is written. The standard says we should say
109 * something about this issue in the documentation...
111 * FUNCTIONS: The CLOCKs structure defines possible functions to
112 * handle various clock functions.
114 * The standard POSIX timer management code assumes the
115 * following: 1.) The k_itimer struct (sched.h) is used for
116 * the timer. 2.) The list, it_lock, it_clock, it_id and
117 * it_pid fields are not modified by timer code.
119 * Permissions: It is assumed that the clock_settime() function defined
120 * for each clock will take care of permission checks. Some
121 * clocks may be set able by any user (i.e. local process
122 * clocks) others not. Currently the only set able clock we
123 * have is CLOCK_REALTIME and its high res counter part, both of
124 * which we beg off on and pass to do_sys_settimeofday().
127 static struct k_clock posix_clocks[MAX_CLOCKS];
130 * These ones are defined below.
132 static int common_nsleep(const clockid_t, int flags, struct timespec *t,
133 struct timespec __user *rmtp);
134 static int common_timer_create(struct k_itimer *new_timer);
135 static void common_timer_get(struct k_itimer *, struct itimerspec *);
136 static int common_timer_set(struct k_itimer *, int,
137 struct itimerspec *, struct itimerspec *);
138 static int common_timer_del(struct k_itimer *timer);
140 static enum hrtimer_restart posix_timer_fn(struct hrtimer *data);
142 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
144 #define lock_timer(tid, flags) \
145 ({ struct k_itimer *__timr; \
146 __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \
150 static int hash(struct signal_struct *sig, unsigned int nr)
152 return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
155 static struct k_itimer *__posix_timers_find(struct hlist_head *head,
156 struct signal_struct *sig,
159 struct k_itimer *timer;
161 hlist_for_each_entry_rcu(timer, head, t_hash) {
162 if ((timer->it_signal == sig) && (timer->it_id == id))
168 static struct k_itimer *posix_timer_by_id(timer_t id)
170 struct signal_struct *sig = current->signal;
171 struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
173 return __posix_timers_find(head, sig, id);
176 static int posix_timer_add(struct k_itimer *timer)
178 struct signal_struct *sig = current->signal;
179 int first_free_id = sig->posix_timer_id;
180 struct hlist_head *head;
184 spin_lock(&hash_lock);
185 head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
186 if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
187 hlist_add_head_rcu(&timer->t_hash, head);
188 ret = sig->posix_timer_id;
190 if (++sig->posix_timer_id < 0)
191 sig->posix_timer_id = 0;
192 if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
193 /* Loop over all possible ids completed */
195 spin_unlock(&hash_lock);
196 } while (ret == -ENOENT);
200 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
202 spin_unlock_irqrestore(&timr->it_lock, flags);
205 /* Get clock_realtime */
206 static int posix_clock_realtime_get(clockid_t which_clock, struct timespec *tp)
208 ktime_get_real_ts(tp);
212 /* Set clock_realtime */
213 static int posix_clock_realtime_set(const clockid_t which_clock,
214 const struct timespec *tp)
216 return do_sys_settimeofday(tp, NULL);
219 static int posix_clock_realtime_adj(const clockid_t which_clock,
222 return do_adjtimex(t);
226 * Get monotonic time for posix timers
228 static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
235 * Get monotonic-raw time for posix timers
237 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
244 static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
246 *tp = current_kernel_time();
250 static int posix_get_monotonic_coarse(clockid_t which_clock,
253 *tp = get_monotonic_coarse();
257 static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
259 *tp = ktime_to_timespec(KTIME_LOW_RES);
263 static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp)
265 get_monotonic_boottime(tp);
269 static int posix_get_tai(clockid_t which_clock, struct timespec *tp)
271 timekeeping_clocktai(tp);
275 static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec *tp)
278 tp->tv_nsec = hrtimer_resolution;
283 * Initialize everything, well, just everything in Posix clocks/timers ;)
285 static __init int init_posix_timers(void)
287 struct k_clock clock_realtime = {
288 .clock_getres = posix_get_hrtimer_res,
289 .clock_get = posix_clock_realtime_get,
290 .clock_set = posix_clock_realtime_set,
291 .clock_adj = posix_clock_realtime_adj,
292 .nsleep = common_nsleep,
293 .nsleep_restart = hrtimer_nanosleep_restart,
294 .timer_create = common_timer_create,
295 .timer_set = common_timer_set,
296 .timer_get = common_timer_get,
297 .timer_del = common_timer_del,
299 struct k_clock clock_monotonic = {
300 .clock_getres = posix_get_hrtimer_res,
301 .clock_get = posix_ktime_get_ts,
302 .nsleep = common_nsleep,
303 .nsleep_restart = hrtimer_nanosleep_restart,
304 .timer_create = common_timer_create,
305 .timer_set = common_timer_set,
306 .timer_get = common_timer_get,
307 .timer_del = common_timer_del,
309 struct k_clock clock_monotonic_raw = {
310 .clock_getres = posix_get_hrtimer_res,
311 .clock_get = posix_get_monotonic_raw,
313 struct k_clock clock_realtime_coarse = {
314 .clock_getres = posix_get_coarse_res,
315 .clock_get = posix_get_realtime_coarse,
317 struct k_clock clock_monotonic_coarse = {
318 .clock_getres = posix_get_coarse_res,
319 .clock_get = posix_get_monotonic_coarse,
321 struct k_clock clock_tai = {
322 .clock_getres = posix_get_hrtimer_res,
323 .clock_get = posix_get_tai,
324 .nsleep = common_nsleep,
325 .nsleep_restart = hrtimer_nanosleep_restart,
326 .timer_create = common_timer_create,
327 .timer_set = common_timer_set,
328 .timer_get = common_timer_get,
329 .timer_del = common_timer_del,
331 struct k_clock clock_boottime = {
332 .clock_getres = posix_get_hrtimer_res,
333 .clock_get = posix_get_boottime,
334 .nsleep = common_nsleep,
335 .nsleep_restart = hrtimer_nanosleep_restart,
336 .timer_create = common_timer_create,
337 .timer_set = common_timer_set,
338 .timer_get = common_timer_get,
339 .timer_del = common_timer_del,
342 posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
343 posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
344 posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
345 posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
346 posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
347 posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime);
348 posix_timers_register_clock(CLOCK_TAI, &clock_tai);
350 posix_timers_cache = kmem_cache_create("posix_timers_cache",
351 sizeof (struct k_itimer), 0, SLAB_PANIC,
356 __initcall(init_posix_timers);
358 static void schedule_next_timer(struct k_itimer *timr)
360 struct hrtimer *timer = &timr->it.real.timer;
362 if (timr->it.real.interval.tv64 == 0)
365 timr->it_overrun += (unsigned int) hrtimer_forward(timer,
366 timer->base->get_time(),
367 timr->it.real.interval);
369 timr->it_overrun_last = timr->it_overrun;
370 timr->it_overrun = -1;
371 ++timr->it_requeue_pending;
372 hrtimer_restart(timer);
376 * This function is exported for use by the signal deliver code. It is
377 * called just prior to the info block being released and passes that
378 * block to us. It's function is to update the overrun entry AND to
379 * restart the timer. It should only be called if the timer is to be
380 * restarted (i.e. we have flagged this in the sys_private entry of the
383 * To protect against the timer going away while the interrupt is queued,
384 * we require that the it_requeue_pending flag be set.
386 void do_schedule_next_timer(struct siginfo *info)
388 struct k_itimer *timr;
391 timr = lock_timer(info->si_tid, &flags);
393 if (timr && timr->it_requeue_pending == info->si_sys_private) {
394 if (timr->it_clock < 0)
395 posix_cpu_timer_schedule(timr);
397 schedule_next_timer(timr);
399 info->si_overrun += timr->it_overrun_last;
403 unlock_timer(timr, flags);
406 int posix_timer_event(struct k_itimer *timr, int si_private)
408 struct task_struct *task;
409 int shared, ret = -1;
411 * FIXME: if ->sigq is queued we can race with
412 * dequeue_signal()->do_schedule_next_timer().
414 * If dequeue_signal() sees the "right" value of
415 * si_sys_private it calls do_schedule_next_timer().
416 * We re-queue ->sigq and drop ->it_lock().
417 * do_schedule_next_timer() locks the timer
418 * and re-schedules it while ->sigq is pending.
419 * Not really bad, but not that we want.
421 timr->sigq->info.si_sys_private = si_private;
424 task = pid_task(timr->it_pid, PIDTYPE_PID);
426 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
427 ret = send_sigqueue(timr->sigq, task, shared);
430 /* If we failed to send the signal the timer stops. */
433 EXPORT_SYMBOL_GPL(posix_timer_event);
436 * This function gets called when a POSIX.1b interval timer expires. It
437 * is used as a callback from the kernel internal timer. The
438 * run_timer_list code ALWAYS calls with interrupts on.
440 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
442 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
444 struct k_itimer *timr;
447 enum hrtimer_restart ret = HRTIMER_NORESTART;
449 timr = container_of(timer, struct k_itimer, it.real.timer);
450 spin_lock_irqsave(&timr->it_lock, flags);
452 if (timr->it.real.interval.tv64 != 0)
453 si_private = ++timr->it_requeue_pending;
455 if (posix_timer_event(timr, si_private)) {
457 * signal was not sent because of sig_ignor
458 * we will not get a call back to restart it AND
459 * it should be restarted.
461 if (timr->it.real.interval.tv64 != 0) {
462 ktime_t now = hrtimer_cb_get_time(timer);
465 * FIXME: What we really want, is to stop this
466 * timer completely and restart it in case the
467 * SIG_IGN is removed. This is a non trivial
468 * change which involves sighand locking
469 * (sigh !), which we don't want to do late in
472 * For now we just let timers with an interval
473 * less than a jiffie expire every jiffie to
474 * avoid softirq starvation in case of SIG_IGN
475 * and a very small interval, which would put
476 * the timer right back on the softirq pending
477 * list. By moving now ahead of time we trick
478 * hrtimer_forward() to expire the timer
479 * later, while we still maintain the overrun
480 * accuracy, but have some inconsistency in
481 * the timer_gettime() case. This is at least
482 * better than a starved softirq. A more
483 * complex fix which solves also another related
484 * inconsistency is already in the pipeline.
486 #ifdef CONFIG_HIGH_RES_TIMERS
488 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
490 if (timr->it.real.interval.tv64 < kj.tv64)
491 now = ktime_add(now, kj);
494 timr->it_overrun += (unsigned int)
495 hrtimer_forward(timer, now,
496 timr->it.real.interval);
497 ret = HRTIMER_RESTART;
498 ++timr->it_requeue_pending;
502 unlock_timer(timr, flags);
506 static struct pid *good_sigevent(sigevent_t * event)
508 struct task_struct *rtn = current->group_leader;
509 int sig = event->sigev_signo;
511 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
512 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
513 !same_thread_group(rtn, current) ||
514 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
517 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
518 (sig <= 0 || sig > SIGRTMAX || sig_kernel_only(sig) ||
519 sig_kernel_coredump(sig)))
522 return task_pid(rtn);
525 void posix_timers_register_clock(const clockid_t clock_id,
526 struct k_clock *new_clock)
528 if ((unsigned) clock_id >= MAX_CLOCKS) {
529 printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
534 if (!new_clock->clock_get) {
535 printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
539 if (!new_clock->clock_getres) {
540 printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
545 posix_clocks[clock_id] = *new_clock;
547 EXPORT_SYMBOL_GPL(posix_timers_register_clock);
549 static struct k_itimer * alloc_posix_timer(void)
551 struct k_itimer *tmr;
552 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
555 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
556 kmem_cache_free(posix_timers_cache, tmr);
559 memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
563 static void k_itimer_rcu_free(struct rcu_head *head)
565 struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
567 kmem_cache_free(posix_timers_cache, tmr);
571 #define IT_ID_NOT_SET 0
572 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
576 spin_lock_irqsave(&hash_lock, flags);
577 hlist_del_rcu(&tmr->t_hash);
578 spin_unlock_irqrestore(&hash_lock, flags);
580 put_pid(tmr->it_pid);
581 sigqueue_free(tmr->sigq);
582 call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
585 static struct k_clock *clockid_to_kclock(const clockid_t id)
588 return (id & CLOCKFD_MASK) == CLOCKFD ?
589 &clock_posix_dynamic : &clock_posix_cpu;
591 if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
593 return &posix_clocks[id];
596 static int common_timer_create(struct k_itimer *new_timer)
598 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
602 /* Create a POSIX.1b interval timer. */
604 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
605 struct sigevent __user *, timer_event_spec,
606 timer_t __user *, created_timer_id)
608 struct k_clock *kc = clockid_to_kclock(which_clock);
609 struct k_itimer *new_timer;
610 int error, new_timer_id;
612 int it_id_set = IT_ID_NOT_SET;
616 if (!kc->timer_create)
619 new_timer = alloc_posix_timer();
620 if (unlikely(!new_timer))
623 spin_lock_init(&new_timer->it_lock);
624 new_timer_id = posix_timer_add(new_timer);
625 if (new_timer_id < 0) {
626 error = new_timer_id;
630 it_id_set = IT_ID_SET;
631 new_timer->it_id = (timer_t) new_timer_id;
632 new_timer->it_clock = which_clock;
633 new_timer->it_overrun = -1;
635 if (timer_event_spec) {
636 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
641 new_timer->it_pid = get_pid(good_sigevent(&event));
643 if (!new_timer->it_pid) {
648 memset(&event.sigev_value, 0, sizeof(event.sigev_value));
649 event.sigev_notify = SIGEV_SIGNAL;
650 event.sigev_signo = SIGALRM;
651 event.sigev_value.sival_int = new_timer->it_id;
652 new_timer->it_pid = get_pid(task_tgid(current));
655 new_timer->it_sigev_notify = event.sigev_notify;
656 new_timer->sigq->info.si_signo = event.sigev_signo;
657 new_timer->sigq->info.si_value = event.sigev_value;
658 new_timer->sigq->info.si_tid = new_timer->it_id;
659 new_timer->sigq->info.si_code = SI_TIMER;
661 if (copy_to_user(created_timer_id,
662 &new_timer_id, sizeof (new_timer_id))) {
667 error = kc->timer_create(new_timer);
671 spin_lock_irq(¤t->sighand->siglock);
672 new_timer->it_signal = current->signal;
673 list_add(&new_timer->list, ¤t->signal->posix_timers);
674 spin_unlock_irq(¤t->sighand->siglock);
678 * In the case of the timer belonging to another task, after
679 * the task is unlocked, the timer is owned by the other task
680 * and may cease to exist at any time. Don't use or modify
681 * new_timer after the unlock call.
684 release_posix_timer(new_timer, it_id_set);
689 * Locking issues: We need to protect the result of the id look up until
690 * we get the timer locked down so it is not deleted under us. The
691 * removal is done under the idr spinlock so we use that here to bridge
692 * the find to the timer lock. To avoid a dead lock, the timer id MUST
693 * be release with out holding the timer lock.
695 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
697 struct k_itimer *timr;
700 * timer_t could be any type >= int and we want to make sure any
701 * @timer_id outside positive int range fails lookup.
703 if ((unsigned long long)timer_id > INT_MAX)
707 timr = posix_timer_by_id(timer_id);
709 spin_lock_irqsave(&timr->it_lock, *flags);
710 if (timr->it_signal == current->signal) {
714 spin_unlock_irqrestore(&timr->it_lock, *flags);
722 * Get the time remaining on a POSIX.1b interval timer. This function
723 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
726 * We have a couple of messes to clean up here. First there is the case
727 * of a timer that has a requeue pending. These timers should appear to
728 * be in the timer list with an expiry as if we were to requeue them
731 * The second issue is the SIGEV_NONE timer which may be active but is
732 * not really ever put in the timer list (to save system resources).
733 * This timer may be expired, and if so, we will do it here. Otherwise
734 * it is the same as a requeue pending timer WRT to what we should
738 common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
740 ktime_t now, remaining, iv;
741 struct hrtimer *timer = &timr->it.real.timer;
743 memset(cur_setting, 0, sizeof(struct itimerspec));
745 iv = timr->it.real.interval;
747 /* interval timer ? */
749 cur_setting->it_interval = ktime_to_timespec(iv);
750 else if (!hrtimer_active(timer) &&
751 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
754 now = timer->base->get_time();
757 * When a requeue is pending or this is a SIGEV_NONE
758 * timer move the expiry time forward by intervals, so
761 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
762 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
763 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
765 remaining = __hrtimer_expires_remaining_adjusted(timer, now);
766 /* Return 0 only, when the timer is expired and not pending */
767 if (remaining.tv64 <= 0) {
769 * A single shot SIGEV_NONE timer must return 0, when
772 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
773 cur_setting->it_value.tv_nsec = 1;
775 cur_setting->it_value = ktime_to_timespec(remaining);
778 /* Get the time remaining on a POSIX.1b interval timer. */
779 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
780 struct itimerspec __user *, setting)
782 struct itimerspec cur_setting;
783 struct k_itimer *timr;
788 timr = lock_timer(timer_id, &flags);
792 kc = clockid_to_kclock(timr->it_clock);
793 if (WARN_ON_ONCE(!kc || !kc->timer_get))
796 kc->timer_get(timr, &cur_setting);
798 unlock_timer(timr, flags);
800 if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
807 * Get the number of overruns of a POSIX.1b interval timer. This is to
808 * be the overrun of the timer last delivered. At the same time we are
809 * accumulating overruns on the next timer. The overrun is frozen when
810 * the signal is delivered, either at the notify time (if the info block
811 * is not queued) or at the actual delivery time (as we are informed by
812 * the call back to do_schedule_next_timer(). So all we need to do is
813 * to pick up the frozen overrun.
815 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
817 struct k_itimer *timr;
821 timr = lock_timer(timer_id, &flags);
825 overrun = timr->it_overrun_last;
826 unlock_timer(timr, flags);
834 static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr)
836 #ifdef CONFIG_PREEMPT_RT_FULL
837 if (kc->timer_set == common_timer_set)
838 hrtimer_wait_for_timer(&timr->it.real.timer);
840 /* FIXME: Whacky hack for posix-cpu-timers */
845 /* Set a POSIX.1b interval timer. */
846 /* timr->it_lock is taken. */
848 common_timer_set(struct k_itimer *timr, int flags,
849 struct itimerspec *new_setting, struct itimerspec *old_setting)
851 struct hrtimer *timer = &timr->it.real.timer;
852 enum hrtimer_mode mode;
855 common_timer_get(timr, old_setting);
857 /* disable the timer */
858 timr->it.real.interval.tv64 = 0;
860 * careful here. If smp we could be in the "fire" routine which will
861 * be spinning as we hold the lock. But this is ONLY an SMP issue.
863 if (hrtimer_try_to_cancel(timer) < 0)
866 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
868 timr->it_overrun_last = 0;
870 /* switch off the timer when it_value is zero */
871 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
874 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
875 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
876 timr->it.real.timer.function = posix_timer_fn;
878 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
880 /* Convert interval */
881 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
883 /* SIGEV_NONE timers are not queued ! See common_timer_get */
884 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
885 /* Setup correct expiry time for relative timers */
886 if (mode == HRTIMER_MODE_REL) {
887 hrtimer_add_expires(timer, timer->base->get_time());
892 hrtimer_start_expires(timer, mode);
896 /* Set a POSIX.1b interval timer */
897 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
898 const struct itimerspec __user *, new_setting,
899 struct itimerspec __user *, old_setting)
901 struct k_itimer *timr;
902 struct itimerspec new_spec, old_spec;
905 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
911 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
914 if (!timespec_valid(&new_spec.it_interval) ||
915 !timespec_valid(&new_spec.it_value))
918 timr = lock_timer(timer_id, &flag);
923 kc = clockid_to_kclock(timr->it_clock);
924 if (WARN_ON_ONCE(!kc || !kc->timer_set))
927 error = kc->timer_set(timr, flags, &new_spec, rtn);
929 unlock_timer(timr, flag);
930 if (error == TIMER_RETRY) {
931 timer_wait_for_callback(kc, timr);
932 rtn = NULL; // We already got the old time...
938 if (old_setting && !error &&
939 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
945 static int common_timer_del(struct k_itimer *timer)
947 timer->it.real.interval.tv64 = 0;
949 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
954 static inline int timer_delete_hook(struct k_itimer *timer)
956 struct k_clock *kc = clockid_to_kclock(timer->it_clock);
958 if (WARN_ON_ONCE(!kc || !kc->timer_del))
960 return kc->timer_del(timer);
963 /* Delete a POSIX.1b interval timer. */
964 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
966 struct k_itimer *timer;
970 timer = lock_timer(timer_id, &flags);
975 if (timer_delete_hook(timer) == TIMER_RETRY) {
976 unlock_timer(timer, flags);
977 timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
984 spin_lock(¤t->sighand->siglock);
985 list_del(&timer->list);
986 spin_unlock(¤t->sighand->siglock);
988 * This keeps any tasks waiting on the spin lock from thinking
989 * they got something (see the lock code above).
991 timer->it_signal = NULL;
993 unlock_timer(timer, flags);
994 release_posix_timer(timer, IT_ID_SET);
999 * return timer owned by the process, used by exit_itimers
1001 static void itimer_delete(struct k_itimer *timer)
1003 unsigned long flags;
1006 spin_lock_irqsave(&timer->it_lock, flags);
1008 /* On RT we can race with a deletion */
1009 if (!timer->it_signal) {
1010 unlock_timer(timer, flags);
1014 if (timer_delete_hook(timer) == TIMER_RETRY) {
1016 unlock_timer(timer, flags);
1017 timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
1022 list_del(&timer->list);
1024 * This keeps any tasks waiting on the spin lock from thinking
1025 * they got something (see the lock code above).
1027 timer->it_signal = NULL;
1029 unlock_timer(timer, flags);
1030 release_posix_timer(timer, IT_ID_SET);
1034 * This is called by do_exit or de_thread, only when there are no more
1035 * references to the shared signal_struct.
1037 void exit_itimers(struct signal_struct *sig)
1039 struct k_itimer *tmr;
1041 while (!list_empty(&sig->posix_timers)) {
1042 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
1047 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1048 const struct timespec __user *, tp)
1050 struct k_clock *kc = clockid_to_kclock(which_clock);
1051 struct timespec new_tp;
1053 if (!kc || !kc->clock_set)
1056 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
1059 return kc->clock_set(which_clock, &new_tp);
1062 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1063 struct timespec __user *,tp)
1065 struct k_clock *kc = clockid_to_kclock(which_clock);
1066 struct timespec kernel_tp;
1072 error = kc->clock_get(which_clock, &kernel_tp);
1074 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
1080 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1081 struct timex __user *, utx)
1083 struct k_clock *kc = clockid_to_kclock(which_clock);
1092 if (copy_from_user(&ktx, utx, sizeof(ktx)))
1095 err = kc->clock_adj(which_clock, &ktx);
1097 if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1103 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1104 struct timespec __user *, tp)
1106 struct k_clock *kc = clockid_to_kclock(which_clock);
1107 struct timespec rtn_tp;
1113 error = kc->clock_getres(which_clock, &rtn_tp);
1115 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
1122 * nanosleep for monotonic and realtime clocks
1124 static int common_nsleep(const clockid_t which_clock, int flags,
1125 struct timespec *tsave, struct timespec __user *rmtp)
1127 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
1128 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1132 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1133 const struct timespec __user *, rqtp,
1134 struct timespec __user *, rmtp)
1136 struct k_clock *kc = clockid_to_kclock(which_clock);
1142 return -ENANOSLEEP_NOTSUP;
1144 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
1147 if (!timespec_valid(&t))
1150 return kc->nsleep(which_clock, flags, &t, rmtp);
1154 * This will restart clock_nanosleep. This is required only by
1155 * compat_clock_nanosleep_restart for now.
1157 long clock_nanosleep_restart(struct restart_block *restart_block)
1159 clockid_t which_clock = restart_block->nanosleep.clockid;
1160 struct k_clock *kc = clockid_to_kclock(which_clock);
1162 if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))
1165 return kc->nsleep_restart(restart_block);