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);
276 * Initialize everything, well, just everything in Posix clocks/timers ;)
278 static __init int init_posix_timers(void)
280 struct k_clock clock_realtime = {
281 .clock_getres = hrtimer_get_res,
282 .clock_get = posix_clock_realtime_get,
283 .clock_set = posix_clock_realtime_set,
284 .clock_adj = posix_clock_realtime_adj,
285 .nsleep = common_nsleep,
286 .nsleep_restart = hrtimer_nanosleep_restart,
287 .timer_create = common_timer_create,
288 .timer_set = common_timer_set,
289 .timer_get = common_timer_get,
290 .timer_del = common_timer_del,
292 struct k_clock clock_monotonic = {
293 .clock_getres = hrtimer_get_res,
294 .clock_get = posix_ktime_get_ts,
295 .nsleep = common_nsleep,
296 .nsleep_restart = hrtimer_nanosleep_restart,
297 .timer_create = common_timer_create,
298 .timer_set = common_timer_set,
299 .timer_get = common_timer_get,
300 .timer_del = common_timer_del,
302 struct k_clock clock_monotonic_raw = {
303 .clock_getres = hrtimer_get_res,
304 .clock_get = posix_get_monotonic_raw,
306 struct k_clock clock_realtime_coarse = {
307 .clock_getres = posix_get_coarse_res,
308 .clock_get = posix_get_realtime_coarse,
310 struct k_clock clock_monotonic_coarse = {
311 .clock_getres = posix_get_coarse_res,
312 .clock_get = posix_get_monotonic_coarse,
314 struct k_clock clock_tai = {
315 .clock_getres = hrtimer_get_res,
316 .clock_get = posix_get_tai,
317 .nsleep = common_nsleep,
318 .nsleep_restart = hrtimer_nanosleep_restart,
319 .timer_create = common_timer_create,
320 .timer_set = common_timer_set,
321 .timer_get = common_timer_get,
322 .timer_del = common_timer_del,
324 struct k_clock clock_boottime = {
325 .clock_getres = hrtimer_get_res,
326 .clock_get = posix_get_boottime,
327 .nsleep = common_nsleep,
328 .nsleep_restart = hrtimer_nanosleep_restart,
329 .timer_create = common_timer_create,
330 .timer_set = common_timer_set,
331 .timer_get = common_timer_get,
332 .timer_del = common_timer_del,
335 posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
336 posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
337 posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
338 posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
339 posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
340 posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime);
341 posix_timers_register_clock(CLOCK_TAI, &clock_tai);
343 posix_timers_cache = kmem_cache_create("posix_timers_cache",
344 sizeof (struct k_itimer), 0, SLAB_PANIC,
349 __initcall(init_posix_timers);
351 static void schedule_next_timer(struct k_itimer *timr)
353 struct hrtimer *timer = &timr->it.real.timer;
355 if (timr->it.real.interval.tv64 == 0)
358 timr->it_overrun += (unsigned int) hrtimer_forward(timer,
359 timer->base->get_time(),
360 timr->it.real.interval);
362 timr->it_overrun_last = timr->it_overrun;
363 timr->it_overrun = -1;
364 ++timr->it_requeue_pending;
365 hrtimer_restart(timer);
369 * This function is exported for use by the signal deliver code. It is
370 * called just prior to the info block being released and passes that
371 * block to us. It's function is to update the overrun entry AND to
372 * restart the timer. It should only be called if the timer is to be
373 * restarted (i.e. we have flagged this in the sys_private entry of the
376 * To protect against the timer going away while the interrupt is queued,
377 * we require that the it_requeue_pending flag be set.
379 void do_schedule_next_timer(struct siginfo *info)
381 struct k_itimer *timr;
384 timr = lock_timer(info->si_tid, &flags);
386 if (timr && timr->it_requeue_pending == info->si_sys_private) {
387 if (timr->it_clock < 0)
388 posix_cpu_timer_schedule(timr);
390 schedule_next_timer(timr);
392 info->si_overrun += timr->it_overrun_last;
396 unlock_timer(timr, flags);
399 int posix_timer_event(struct k_itimer *timr, int si_private)
401 struct task_struct *task;
402 int shared, ret = -1;
404 * FIXME: if ->sigq is queued we can race with
405 * dequeue_signal()->do_schedule_next_timer().
407 * If dequeue_signal() sees the "right" value of
408 * si_sys_private it calls do_schedule_next_timer().
409 * We re-queue ->sigq and drop ->it_lock().
410 * do_schedule_next_timer() locks the timer
411 * and re-schedules it while ->sigq is pending.
412 * Not really bad, but not that we want.
414 timr->sigq->info.si_sys_private = si_private;
417 task = pid_task(timr->it_pid, PIDTYPE_PID);
419 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
420 ret = send_sigqueue(timr->sigq, task, shared);
423 /* If we failed to send the signal the timer stops. */
426 EXPORT_SYMBOL_GPL(posix_timer_event);
429 * This function gets called when a POSIX.1b interval timer expires. It
430 * is used as a callback from the kernel internal timer. The
431 * run_timer_list code ALWAYS calls with interrupts on.
433 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
435 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
437 struct k_itimer *timr;
440 enum hrtimer_restart ret = HRTIMER_NORESTART;
442 timr = container_of(timer, struct k_itimer, it.real.timer);
443 spin_lock_irqsave(&timr->it_lock, flags);
445 if (timr->it.real.interval.tv64 != 0)
446 si_private = ++timr->it_requeue_pending;
448 if (posix_timer_event(timr, si_private)) {
450 * signal was not sent because of sig_ignor
451 * we will not get a call back to restart it AND
452 * it should be restarted.
454 if (timr->it.real.interval.tv64 != 0) {
455 ktime_t now = hrtimer_cb_get_time(timer);
458 * FIXME: What we really want, is to stop this
459 * timer completely and restart it in case the
460 * SIG_IGN is removed. This is a non trivial
461 * change which involves sighand locking
462 * (sigh !), which we don't want to do late in
465 * For now we just let timers with an interval
466 * less than a jiffie expire every jiffie to
467 * avoid softirq starvation in case of SIG_IGN
468 * and a very small interval, which would put
469 * the timer right back on the softirq pending
470 * list. By moving now ahead of time we trick
471 * hrtimer_forward() to expire the timer
472 * later, while we still maintain the overrun
473 * accuracy, but have some inconsistency in
474 * the timer_gettime() case. This is at least
475 * better than a starved softirq. A more
476 * complex fix which solves also another related
477 * inconsistency is already in the pipeline.
479 #ifdef CONFIG_HIGH_RES_TIMERS
481 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
483 if (timr->it.real.interval.tv64 < kj.tv64)
484 now = ktime_add(now, kj);
487 timr->it_overrun += (unsigned int)
488 hrtimer_forward(timer, now,
489 timr->it.real.interval);
490 ret = HRTIMER_RESTART;
491 ++timr->it_requeue_pending;
495 unlock_timer(timr, flags);
499 static struct pid *good_sigevent(sigevent_t * event)
501 struct task_struct *rtn = current->group_leader;
502 int sig = event->sigev_signo;
504 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
505 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
506 !same_thread_group(rtn, current) ||
507 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
510 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
511 (sig <= 0 || sig > SIGRTMAX || sig_kernel_only(sig) ||
512 sig_kernel_coredump(sig)))
515 return task_pid(rtn);
518 void posix_timers_register_clock(const clockid_t clock_id,
519 struct k_clock *new_clock)
521 if ((unsigned) clock_id >= MAX_CLOCKS) {
522 printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
527 if (!new_clock->clock_get) {
528 printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
532 if (!new_clock->clock_getres) {
533 printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
538 posix_clocks[clock_id] = *new_clock;
540 EXPORT_SYMBOL_GPL(posix_timers_register_clock);
542 static struct k_itimer * alloc_posix_timer(void)
544 struct k_itimer *tmr;
545 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
548 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
549 kmem_cache_free(posix_timers_cache, tmr);
552 memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
556 static void k_itimer_rcu_free(struct rcu_head *head)
558 struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
560 kmem_cache_free(posix_timers_cache, tmr);
564 #define IT_ID_NOT_SET 0
565 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
569 spin_lock_irqsave(&hash_lock, flags);
570 hlist_del_rcu(&tmr->t_hash);
571 spin_unlock_irqrestore(&hash_lock, flags);
573 put_pid(tmr->it_pid);
574 sigqueue_free(tmr->sigq);
575 call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
578 static struct k_clock *clockid_to_kclock(const clockid_t id)
581 return (id & CLOCKFD_MASK) == CLOCKFD ?
582 &clock_posix_dynamic : &clock_posix_cpu;
584 if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
586 return &posix_clocks[id];
589 static int common_timer_create(struct k_itimer *new_timer)
591 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
595 /* Create a POSIX.1b interval timer. */
597 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
598 struct sigevent __user *, timer_event_spec,
599 timer_t __user *, created_timer_id)
601 struct k_clock *kc = clockid_to_kclock(which_clock);
602 struct k_itimer *new_timer;
603 int error, new_timer_id;
605 int it_id_set = IT_ID_NOT_SET;
609 if (!kc->timer_create)
612 new_timer = alloc_posix_timer();
613 if (unlikely(!new_timer))
616 spin_lock_init(&new_timer->it_lock);
617 new_timer_id = posix_timer_add(new_timer);
618 if (new_timer_id < 0) {
619 error = new_timer_id;
623 it_id_set = IT_ID_SET;
624 new_timer->it_id = (timer_t) new_timer_id;
625 new_timer->it_clock = which_clock;
626 new_timer->it_overrun = -1;
628 if (timer_event_spec) {
629 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
634 new_timer->it_pid = get_pid(good_sigevent(&event));
636 if (!new_timer->it_pid) {
641 memset(&event.sigev_value, 0, sizeof(event.sigev_value));
642 event.sigev_notify = SIGEV_SIGNAL;
643 event.sigev_signo = SIGALRM;
644 event.sigev_value.sival_int = new_timer->it_id;
645 new_timer->it_pid = get_pid(task_tgid(current));
648 new_timer->it_sigev_notify = event.sigev_notify;
649 new_timer->sigq->info.si_signo = event.sigev_signo;
650 new_timer->sigq->info.si_value = event.sigev_value;
651 new_timer->sigq->info.si_tid = new_timer->it_id;
652 new_timer->sigq->info.si_code = SI_TIMER;
654 if (copy_to_user(created_timer_id,
655 &new_timer_id, sizeof (new_timer_id))) {
660 error = kc->timer_create(new_timer);
664 spin_lock_irq(¤t->sighand->siglock);
665 new_timer->it_signal = current->signal;
666 list_add(&new_timer->list, ¤t->signal->posix_timers);
667 spin_unlock_irq(¤t->sighand->siglock);
671 * In the case of the timer belonging to another task, after
672 * the task is unlocked, the timer is owned by the other task
673 * and may cease to exist at any time. Don't use or modify
674 * new_timer after the unlock call.
677 release_posix_timer(new_timer, it_id_set);
682 * Locking issues: We need to protect the result of the id look up until
683 * we get the timer locked down so it is not deleted under us. The
684 * removal is done under the idr spinlock so we use that here to bridge
685 * the find to the timer lock. To avoid a dead lock, the timer id MUST
686 * be release with out holding the timer lock.
688 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
690 struct k_itimer *timr;
693 * timer_t could be any type >= int and we want to make sure any
694 * @timer_id outside positive int range fails lookup.
696 if ((unsigned long long)timer_id > INT_MAX)
700 timr = posix_timer_by_id(timer_id);
702 spin_lock_irqsave(&timr->it_lock, *flags);
703 if (timr->it_signal == current->signal) {
707 spin_unlock_irqrestore(&timr->it_lock, *flags);
715 * Get the time remaining on a POSIX.1b interval timer. This function
716 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
719 * We have a couple of messes to clean up here. First there is the case
720 * of a timer that has a requeue pending. These timers should appear to
721 * be in the timer list with an expiry as if we were to requeue them
724 * The second issue is the SIGEV_NONE timer which may be active but is
725 * not really ever put in the timer list (to save system resources).
726 * This timer may be expired, and if so, we will do it here. Otherwise
727 * it is the same as a requeue pending timer WRT to what we should
731 common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
733 ktime_t now, remaining, iv;
734 struct hrtimer *timer = &timr->it.real.timer;
736 memset(cur_setting, 0, sizeof(struct itimerspec));
738 iv = timr->it.real.interval;
740 /* interval timer ? */
742 cur_setting->it_interval = ktime_to_timespec(iv);
743 else if (!hrtimer_active(timer) &&
744 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
747 now = timer->base->get_time();
750 * When a requeue is pending or this is a SIGEV_NONE
751 * timer move the expiry time forward by intervals, so
754 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
755 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
756 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
758 remaining = ktime_sub(hrtimer_get_expires(timer), now);
759 /* Return 0 only, when the timer is expired and not pending */
760 if (remaining.tv64 <= 0) {
762 * A single shot SIGEV_NONE timer must return 0, when
765 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
766 cur_setting->it_value.tv_nsec = 1;
768 cur_setting->it_value = ktime_to_timespec(remaining);
771 /* Get the time remaining on a POSIX.1b interval timer. */
772 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
773 struct itimerspec __user *, setting)
775 struct itimerspec cur_setting;
776 struct k_itimer *timr;
781 timr = lock_timer(timer_id, &flags);
785 kc = clockid_to_kclock(timr->it_clock);
786 if (WARN_ON_ONCE(!kc || !kc->timer_get))
789 kc->timer_get(timr, &cur_setting);
791 unlock_timer(timr, flags);
793 if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
800 * Get the number of overruns of a POSIX.1b interval timer. This is to
801 * be the overrun of the timer last delivered. At the same time we are
802 * accumulating overruns on the next timer. The overrun is frozen when
803 * the signal is delivered, either at the notify time (if the info block
804 * is not queued) or at the actual delivery time (as we are informed by
805 * the call back to do_schedule_next_timer(). So all we need to do is
806 * to pick up the frozen overrun.
808 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
810 struct k_itimer *timr;
814 timr = lock_timer(timer_id, &flags);
818 overrun = timr->it_overrun_last;
819 unlock_timer(timr, flags);
827 static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr)
829 #ifdef CONFIG_PREEMPT_RT_FULL
830 if (kc->timer_set == common_timer_set)
831 hrtimer_wait_for_timer(&timr->it.real.timer);
833 /* FIXME: Whacky hack for posix-cpu-timers */
838 /* Set a POSIX.1b interval timer. */
839 /* timr->it_lock is taken. */
841 common_timer_set(struct k_itimer *timr, int flags,
842 struct itimerspec *new_setting, struct itimerspec *old_setting)
844 struct hrtimer *timer = &timr->it.real.timer;
845 enum hrtimer_mode mode;
848 common_timer_get(timr, old_setting);
850 /* disable the timer */
851 timr->it.real.interval.tv64 = 0;
853 * careful here. If smp we could be in the "fire" routine which will
854 * be spinning as we hold the lock. But this is ONLY an SMP issue.
856 if (hrtimer_try_to_cancel(timer) < 0)
859 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
861 timr->it_overrun_last = 0;
863 /* switch off the timer when it_value is zero */
864 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
867 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
868 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
869 timr->it.real.timer.function = posix_timer_fn;
871 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
873 /* Convert interval */
874 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
876 /* SIGEV_NONE timers are not queued ! See common_timer_get */
877 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
878 /* Setup correct expiry time for relative timers */
879 if (mode == HRTIMER_MODE_REL) {
880 hrtimer_add_expires(timer, timer->base->get_time());
885 hrtimer_start_expires(timer, mode);
889 /* Set a POSIX.1b interval timer */
890 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
891 const struct itimerspec __user *, new_setting,
892 struct itimerspec __user *, old_setting)
894 struct k_itimer *timr;
895 struct itimerspec new_spec, old_spec;
898 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
904 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
907 if (!timespec_valid(&new_spec.it_interval) ||
908 !timespec_valid(&new_spec.it_value))
911 timr = lock_timer(timer_id, &flag);
916 kc = clockid_to_kclock(timr->it_clock);
917 if (WARN_ON_ONCE(!kc || !kc->timer_set))
920 error = kc->timer_set(timr, flags, &new_spec, rtn);
922 unlock_timer(timr, flag);
923 if (error == TIMER_RETRY) {
924 timer_wait_for_callback(kc, timr);
925 rtn = NULL; // We already got the old time...
931 if (old_setting && !error &&
932 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
938 static int common_timer_del(struct k_itimer *timer)
940 timer->it.real.interval.tv64 = 0;
942 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
947 static inline int timer_delete_hook(struct k_itimer *timer)
949 struct k_clock *kc = clockid_to_kclock(timer->it_clock);
951 if (WARN_ON_ONCE(!kc || !kc->timer_del))
953 return kc->timer_del(timer);
956 /* Delete a POSIX.1b interval timer. */
957 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
959 struct k_itimer *timer;
963 timer = lock_timer(timer_id, &flags);
968 if (timer_delete_hook(timer) == TIMER_RETRY) {
969 unlock_timer(timer, flags);
970 timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
977 spin_lock(¤t->sighand->siglock);
978 list_del(&timer->list);
979 spin_unlock(¤t->sighand->siglock);
981 * This keeps any tasks waiting on the spin lock from thinking
982 * they got something (see the lock code above).
984 timer->it_signal = NULL;
986 unlock_timer(timer, flags);
987 release_posix_timer(timer, IT_ID_SET);
992 * return timer owned by the process, used by exit_itimers
994 static void itimer_delete(struct k_itimer *timer)
999 spin_lock_irqsave(&timer->it_lock, flags);
1001 /* On RT we can race with a deletion */
1002 if (!timer->it_signal) {
1003 unlock_timer(timer, flags);
1007 if (timer_delete_hook(timer) == TIMER_RETRY) {
1009 unlock_timer(timer, flags);
1010 timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
1015 list_del(&timer->list);
1017 * This keeps any tasks waiting on the spin lock from thinking
1018 * they got something (see the lock code above).
1020 timer->it_signal = NULL;
1022 unlock_timer(timer, flags);
1023 release_posix_timer(timer, IT_ID_SET);
1027 * This is called by do_exit or de_thread, only when there are no more
1028 * references to the shared signal_struct.
1030 void exit_itimers(struct signal_struct *sig)
1032 struct k_itimer *tmr;
1034 while (!list_empty(&sig->posix_timers)) {
1035 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
1040 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1041 const struct timespec __user *, tp)
1043 struct k_clock *kc = clockid_to_kclock(which_clock);
1044 struct timespec new_tp;
1046 if (!kc || !kc->clock_set)
1049 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
1052 return kc->clock_set(which_clock, &new_tp);
1055 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1056 struct timespec __user *,tp)
1058 struct k_clock *kc = clockid_to_kclock(which_clock);
1059 struct timespec kernel_tp;
1065 error = kc->clock_get(which_clock, &kernel_tp);
1067 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
1073 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1074 struct timex __user *, utx)
1076 struct k_clock *kc = clockid_to_kclock(which_clock);
1085 if (copy_from_user(&ktx, utx, sizeof(ktx)))
1088 err = kc->clock_adj(which_clock, &ktx);
1090 if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1096 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1097 struct timespec __user *, tp)
1099 struct k_clock *kc = clockid_to_kclock(which_clock);
1100 struct timespec rtn_tp;
1106 error = kc->clock_getres(which_clock, &rtn_tp);
1108 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
1115 * nanosleep for monotonic and realtime clocks
1117 static int common_nsleep(const clockid_t which_clock, int flags,
1118 struct timespec *tsave, struct timespec __user *rmtp)
1120 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
1121 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1125 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1126 const struct timespec __user *, rqtp,
1127 struct timespec __user *, rmtp)
1129 struct k_clock *kc = clockid_to_kclock(which_clock);
1135 return -ENANOSLEEP_NOTSUP;
1137 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
1140 if (!timespec_valid(&t))
1143 return kc->nsleep(which_clock, flags, &t, rmtp);
1147 * This will restart clock_nanosleep. This is required only by
1148 * compat_clock_nanosleep_restart for now.
1150 long clock_nanosleep_restart(struct restart_block *restart_block)
1152 clockid_t which_clock = restart_block->nanosleep.clockid;
1153 struct k_clock *kc = clockid_to_kclock(which_clock);
1155 if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))
1158 return kc->nsleep_restart(restart_block);