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1/*
2 * linux/kernel/posix-timers.c
3 *
4 *
5 * 2002-10-15 Posix Clocks & timers
6 * by George Anzinger george@mvista.com
7 *
8 * Copyright (C) 2002 2003 by MontaVista Software.
9 *
10 * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
11 * Copyright (C) 2004 Boris Hu
12 *
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.
17 *
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.
22
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.
26 *
27 * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
28 */
29
30/* These are all the functions necessary to implement
31 * POSIX clocks & timers
32 */
33#include <linux/mm.h>
34#include <linux/interrupt.h>
35#include <linux/slab.h>
36#include <linux/time.h>
37#include <linux/mutex.h>
38
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>
51
52/*
53 * Management arrays for POSIX timers. Timers are now kept in static hash table
54 * with 512 entries.
55 * Timer ids are allocated by local routine, which selects proper hash head by
56 * key, constructed from current->signal address and per signal struct counter.
57 * This keeps timer ids unique per process, but now they can intersect between
58 * processes.
59 */
60
61/*
62 * Lets keep our timers in a slab cache :-)
63 */
64static struct kmem_cache *posix_timers_cache;
65
66static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
67static DEFINE_SPINLOCK(hash_lock);
68
69/*
70 * we assume that the new SIGEV_THREAD_ID shares no bits with the other
71 * SIGEV values. Here we put out an error if this assumption fails.
72 */
73#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
74 ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
75#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
76#endif
77
78/*
79 * parisc wants ENOTSUP instead of EOPNOTSUPP
80 */
81#ifndef ENOTSUP
82# define ENANOSLEEP_NOTSUP EOPNOTSUPP
83#else
84# define ENANOSLEEP_NOTSUP ENOTSUP
85#endif
86
87/*
88 * The timer ID is turned into a timer address by idr_find().
89 * Verifying a valid ID consists of:
90 *
91 * a) checking that idr_find() returns other than -1.
92 * b) checking that the timer id matches the one in the timer itself.
93 * c) that the timer owner is in the callers thread group.
94 */
95
96/*
97 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
98 * to implement others. This structure defines the various
99 * clocks.
100 *
101 * RESOLUTION: Clock resolution is used to round up timer and interval
102 * times, NOT to report clock times, which are reported with as
103 * much resolution as the system can muster. In some cases this
104 * resolution may depend on the underlying clock hardware and
105 * may not be quantifiable until run time, and only then is the
106 * necessary code is written. The standard says we should say
107 * something about this issue in the documentation...
108 *
109 * FUNCTIONS: The CLOCKs structure defines possible functions to
110 * handle various clock functions.
111 *
112 * The standard POSIX timer management code assumes the
113 * following: 1.) The k_itimer struct (sched.h) is used for
114 * the timer. 2.) The list, it_lock, it_clock, it_id and
115 * it_pid fields are not modified by timer code.
116 *
117 * Permissions: It is assumed that the clock_settime() function defined
118 * for each clock will take care of permission checks. Some
119 * clocks may be set able by any user (i.e. local process
120 * clocks) others not. Currently the only set able clock we
121 * have is CLOCK_REALTIME and its high res counter part, both of
122 * which we beg off on and pass to do_sys_settimeofday().
123 */
124
125static struct k_clock posix_clocks[MAX_CLOCKS];
126
127/*
128 * These ones are defined below.
129 */
130static int common_nsleep(const clockid_t, int flags, struct timespec *t,
131 struct timespec __user *rmtp);
132static int common_timer_create(struct k_itimer *new_timer);
133static void common_timer_get(struct k_itimer *, struct itimerspec *);
134static int common_timer_set(struct k_itimer *, int,
135 struct itimerspec *, struct itimerspec *);
136static int common_timer_del(struct k_itimer *timer);
137
138static enum hrtimer_restart posix_timer_fn(struct hrtimer *data);
139
140static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
141
142#define lock_timer(tid, flags) \
143({ struct k_itimer *__timr; \
144 __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \
145 __timr; \
146})
147
148static int hash(struct signal_struct *sig, unsigned int nr)
149{
150 return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
151}
152
153static struct k_itimer *__posix_timers_find(struct hlist_head *head,
154 struct signal_struct *sig,
155 timer_t id)
156{
157 struct k_itimer *timer;
158
159 hlist_for_each_entry_rcu(timer, head, t_hash) {
160 if ((timer->it_signal == sig) && (timer->it_id == id))
161 return timer;
162 }
163 return NULL;
164}
165
166static struct k_itimer *posix_timer_by_id(timer_t id)
167{
168 struct signal_struct *sig = current->signal;
169 struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
170
171 return __posix_timers_find(head, sig, id);
172}
173
174static int posix_timer_add(struct k_itimer *timer)
175{
176 struct signal_struct *sig = current->signal;
177 int first_free_id = sig->posix_timer_id;
178 struct hlist_head *head;
179 int ret = -ENOENT;
180
181 do {
182 spin_lock(&hash_lock);
183 head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
184 if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
185 hlist_add_head_rcu(&timer->t_hash, head);
186 ret = sig->posix_timer_id;
187 }
188 if (++sig->posix_timer_id < 0)
189 sig->posix_timer_id = 0;
190 if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
191 /* Loop over all possible ids completed */
192 ret = -EAGAIN;
193 spin_unlock(&hash_lock);
194 } while (ret == -ENOENT);
195 return ret;
196}
197
198static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
199{
200 spin_unlock_irqrestore(&timr->it_lock, flags);
201}
202
203/* Get clock_realtime */
204static int posix_clock_realtime_get(clockid_t which_clock, struct timespec *tp)
205{
206 ktime_get_real_ts(tp);
207 return 0;
208}
209
210/* Set clock_realtime */
211static int posix_clock_realtime_set(const clockid_t which_clock,
212 const struct timespec *tp)
213{
214 return do_sys_settimeofday(tp, NULL);
215}
216
217static int posix_clock_realtime_adj(const clockid_t which_clock,
218 struct timex *t)
219{
220 return do_adjtimex(t);
221}
222
223/*
224 * Get monotonic time for posix timers
225 */
226static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
227{
228 ktime_get_ts(tp);
229 return 0;
230}
231
232/*
233 * Get monotonic-raw time for posix timers
234 */
235static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
236{
237 getrawmonotonic(tp);
238 return 0;
239}
240
241
242static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
243{
244 *tp = current_kernel_time();
245 return 0;
246}
247
248static int posix_get_monotonic_coarse(clockid_t which_clock,
249 struct timespec *tp)
250{
251 *tp = get_monotonic_coarse();
252 return 0;
253}
254
255static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
256{
257 *tp = ktime_to_timespec(KTIME_LOW_RES);
258 return 0;
259}
260
261static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp)
262{
263 get_monotonic_boottime(tp);
264 return 0;
265}
266
267static int posix_get_tai(clockid_t which_clock, struct timespec *tp)
268{
269 timekeeping_clocktai(tp);
270 return 0;
271}
272
273/*
274 * Initialize everything, well, just everything in Posix clocks/timers ;)
275 */
276static __init int init_posix_timers(void)
277{
278 struct k_clock clock_realtime = {
279 .clock_getres = hrtimer_get_res,
280 .clock_get = posix_clock_realtime_get,
281 .clock_set = posix_clock_realtime_set,
282 .clock_adj = posix_clock_realtime_adj,
283 .nsleep = common_nsleep,
284 .nsleep_restart = hrtimer_nanosleep_restart,
285 .timer_create = common_timer_create,
286 .timer_set = common_timer_set,
287 .timer_get = common_timer_get,
288 .timer_del = common_timer_del,
289 };
290 struct k_clock clock_monotonic = {
291 .clock_getres = hrtimer_get_res,
292 .clock_get = posix_ktime_get_ts,
293 .nsleep = common_nsleep,
294 .nsleep_restart = hrtimer_nanosleep_restart,
295 .timer_create = common_timer_create,
296 .timer_set = common_timer_set,
297 .timer_get = common_timer_get,
298 .timer_del = common_timer_del,
299 };
300 struct k_clock clock_monotonic_raw = {
301 .clock_getres = hrtimer_get_res,
302 .clock_get = posix_get_monotonic_raw,
303 };
304 struct k_clock clock_realtime_coarse = {
305 .clock_getres = posix_get_coarse_res,
306 .clock_get = posix_get_realtime_coarse,
307 };
308 struct k_clock clock_monotonic_coarse = {
309 .clock_getres = posix_get_coarse_res,
310 .clock_get = posix_get_monotonic_coarse,
311 };
312 struct k_clock clock_tai = {
313 .clock_getres = hrtimer_get_res,
314 .clock_get = posix_get_tai,
315 .nsleep = common_nsleep,
316 .nsleep_restart = hrtimer_nanosleep_restart,
317 .timer_create = common_timer_create,
318 .timer_set = common_timer_set,
319 .timer_get = common_timer_get,
320 .timer_del = common_timer_del,
321 };
322 struct k_clock clock_boottime = {
323 .clock_getres = hrtimer_get_res,
324 .clock_get = posix_get_boottime,
325 .nsleep = common_nsleep,
326 .nsleep_restart = hrtimer_nanosleep_restart,
327 .timer_create = common_timer_create,
328 .timer_set = common_timer_set,
329 .timer_get = common_timer_get,
330 .timer_del = common_timer_del,
331 };
332
333 posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
334 posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
335 posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
336 posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
337 posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
338 posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime);
339 posix_timers_register_clock(CLOCK_TAI, &clock_tai);
340
341 posix_timers_cache = kmem_cache_create("posix_timers_cache",
342 sizeof (struct k_itimer), 0, SLAB_PANIC,
343 NULL);
344 return 0;
345}
346
347__initcall(init_posix_timers);
348
349static void schedule_next_timer(struct k_itimer *timr)
350{
351 struct hrtimer *timer = &timr->it.real.timer;
352
353 if (timr->it.real.interval.tv64 == 0)
354 return;
355
356 timr->it_overrun += (unsigned int) hrtimer_forward(timer,
357 timer->base->get_time(),
358 timr->it.real.interval);
359
360 timr->it_overrun_last = timr->it_overrun;
361 timr->it_overrun = -1;
362 ++timr->it_requeue_pending;
363 hrtimer_restart(timer);
364}
365
366/*
367 * This function is exported for use by the signal deliver code. It is
368 * called just prior to the info block being released and passes that
369 * block to us. It's function is to update the overrun entry AND to
370 * restart the timer. It should only be called if the timer is to be
371 * restarted (i.e. we have flagged this in the sys_private entry of the
372 * info block).
373 *
374 * To protect against the timer going away while the interrupt is queued,
375 * we require that the it_requeue_pending flag be set.
376 */
377void do_schedule_next_timer(struct siginfo *info)
378{
379 struct k_itimer *timr;
380 unsigned long flags;
381
382 timr = lock_timer(info->si_tid, &flags);
383
384 if (timr && timr->it_requeue_pending == info->si_sys_private) {
385 if (timr->it_clock < 0)
386 posix_cpu_timer_schedule(timr);
387 else
388 schedule_next_timer(timr);
389
390 info->si_overrun += timr->it_overrun_last;
391 }
392
393 if (timr)
394 unlock_timer(timr, flags);
395}
396
397int posix_timer_event(struct k_itimer *timr, int si_private)
398{
399 struct task_struct *task;
400 int shared, ret = -1;
401 /*
402 * FIXME: if ->sigq is queued we can race with
403 * dequeue_signal()->do_schedule_next_timer().
404 *
405 * If dequeue_signal() sees the "right" value of
406 * si_sys_private it calls do_schedule_next_timer().
407 * We re-queue ->sigq and drop ->it_lock().
408 * do_schedule_next_timer() locks the timer
409 * and re-schedules it while ->sigq is pending.
410 * Not really bad, but not that we want.
411 */
412 timr->sigq->info.si_sys_private = si_private;
413
414 rcu_read_lock();
415 task = pid_task(timr->it_pid, PIDTYPE_PID);
416 if (task) {
417 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
418 ret = send_sigqueue(timr->sigq, task, shared);
419 }
420 rcu_read_unlock();
421 /* If we failed to send the signal the timer stops. */
422 return ret > 0;
423}
424EXPORT_SYMBOL_GPL(posix_timer_event);
425
426/*
427 * This function gets called when a POSIX.1b interval timer expires. It
428 * is used as a callback from the kernel internal timer. The
429 * run_timer_list code ALWAYS calls with interrupts on.
430
431 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
432 */
433static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
434{
435 struct k_itimer *timr;
436 unsigned long flags;
437 int si_private = 0;
438 enum hrtimer_restart ret = HRTIMER_NORESTART;
439
440 timr = container_of(timer, struct k_itimer, it.real.timer);
441 spin_lock_irqsave(&timr->it_lock, flags);
442
443 if (timr->it.real.interval.tv64 != 0)
444 si_private = ++timr->it_requeue_pending;
445
446 if (posix_timer_event(timr, si_private)) {
447 /*
448 * signal was not sent because of sig_ignor
449 * we will not get a call back to restart it AND
450 * it should be restarted.
451 */
452 if (timr->it.real.interval.tv64 != 0) {
453 ktime_t now = hrtimer_cb_get_time(timer);
454
455 /*
456 * FIXME: What we really want, is to stop this
457 * timer completely and restart it in case the
458 * SIG_IGN is removed. This is a non trivial
459 * change which involves sighand locking
460 * (sigh !), which we don't want to do late in
461 * the release cycle.
462 *
463 * For now we just let timers with an interval
464 * less than a jiffie expire every jiffie to
465 * avoid softirq starvation in case of SIG_IGN
466 * and a very small interval, which would put
467 * the timer right back on the softirq pending
468 * list. By moving now ahead of time we trick
469 * hrtimer_forward() to expire the timer
470 * later, while we still maintain the overrun
471 * accuracy, but have some inconsistency in
472 * the timer_gettime() case. This is at least
473 * better than a starved softirq. A more
474 * complex fix which solves also another related
475 * inconsistency is already in the pipeline.
476 */
477#ifdef CONFIG_HIGH_RES_TIMERS
478 {
479 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
480
481 if (timr->it.real.interval.tv64 < kj.tv64)
482 now = ktime_add(now, kj);
483 }
484#endif
485 timr->it_overrun += (unsigned int)
486 hrtimer_forward(timer, now,
487 timr->it.real.interval);
488 ret = HRTIMER_RESTART;
489 ++timr->it_requeue_pending;
490 }
491 }
492
493 unlock_timer(timr, flags);
494 return ret;
495}
496
497static struct pid *good_sigevent(sigevent_t * event)
498{
499 struct task_struct *rtn = current->group_leader;
500
501 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
502 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
503 !same_thread_group(rtn, current) ||
504 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
505 return NULL;
506
507 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
508 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
509 return NULL;
510
511 return task_pid(rtn);
512}
513
514void posix_timers_register_clock(const clockid_t clock_id,
515 struct k_clock *new_clock)
516{
517 if ((unsigned) clock_id >= MAX_CLOCKS) {
518 printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
519 clock_id);
520 return;
521 }
522
523 if (!new_clock->clock_get) {
524 printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
525 clock_id);
526 return;
527 }
528 if (!new_clock->clock_getres) {
529 printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
530 clock_id);
531 return;
532 }
533
534 posix_clocks[clock_id] = *new_clock;
535}
536EXPORT_SYMBOL_GPL(posix_timers_register_clock);
537
538static struct k_itimer * alloc_posix_timer(void)
539{
540 struct k_itimer *tmr;
541 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
542 if (!tmr)
543 return tmr;
544 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
545 kmem_cache_free(posix_timers_cache, tmr);
546 return NULL;
547 }
548 memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
549 return tmr;
550}
551
552static void k_itimer_rcu_free(struct rcu_head *head)
553{
554 struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
555
556 kmem_cache_free(posix_timers_cache, tmr);
557}
558
559#define IT_ID_SET 1
560#define IT_ID_NOT_SET 0
561static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
562{
563 if (it_id_set) {
564 unsigned long flags;
565 spin_lock_irqsave(&hash_lock, flags);
566 hlist_del_rcu(&tmr->t_hash);
567 spin_unlock_irqrestore(&hash_lock, flags);
568 }
569 put_pid(tmr->it_pid);
570 sigqueue_free(tmr->sigq);
571 call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
572}
573
574static struct k_clock *clockid_to_kclock(const clockid_t id)
575{
576 if (id < 0)
577 return (id & CLOCKFD_MASK) == CLOCKFD ?
578 &clock_posix_dynamic : &clock_posix_cpu;
579
580 if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
581 return NULL;
582 return &posix_clocks[id];
583}
584
585static int common_timer_create(struct k_itimer *new_timer)
586{
587 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
588 return 0;
589}
590
591/* Create a POSIX.1b interval timer. */
592
593SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
594 struct sigevent __user *, timer_event_spec,
595 timer_t __user *, created_timer_id)
596{
597 struct k_clock *kc = clockid_to_kclock(which_clock);
598 struct k_itimer *new_timer;
599 int error, new_timer_id;
600 sigevent_t event;
601 int it_id_set = IT_ID_NOT_SET;
602
603 if (!kc)
604 return -EINVAL;
605 if (!kc->timer_create)
606 return -EOPNOTSUPP;
607
608 new_timer = alloc_posix_timer();
609 if (unlikely(!new_timer))
610 return -EAGAIN;
611
612 spin_lock_init(&new_timer->it_lock);
613 new_timer_id = posix_timer_add(new_timer);
614 if (new_timer_id < 0) {
615 error = new_timer_id;
616 goto out;
617 }
618
619 it_id_set = IT_ID_SET;
620 new_timer->it_id = (timer_t) new_timer_id;
621 new_timer->it_clock = which_clock;
622 new_timer->it_overrun = -1;
623
624 if (timer_event_spec) {
625 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
626 error = -EFAULT;
627 goto out;
628 }
629 rcu_read_lock();
630 new_timer->it_pid = get_pid(good_sigevent(&event));
631 rcu_read_unlock();
632 if (!new_timer->it_pid) {
633 error = -EINVAL;
634 goto out;
635 }
636 } else {
637 event.sigev_notify = SIGEV_SIGNAL;
638 event.sigev_signo = SIGALRM;
639 event.sigev_value.sival_int = new_timer->it_id;
640 new_timer->it_pid = get_pid(task_tgid(current));
641 }
642
643 new_timer->it_sigev_notify = event.sigev_notify;
644 new_timer->sigq->info.si_signo = event.sigev_signo;
645 new_timer->sigq->info.si_value = event.sigev_value;
646 new_timer->sigq->info.si_tid = new_timer->it_id;
647 new_timer->sigq->info.si_code = SI_TIMER;
648
649 if (copy_to_user(created_timer_id,
650 &new_timer_id, sizeof (new_timer_id))) {
651 error = -EFAULT;
652 goto out;
653 }
654
655 error = kc->timer_create(new_timer);
656 if (error)
657 goto out;
658
659 spin_lock_irq(¤t->sighand->siglock);
660 new_timer->it_signal = current->signal;
661 list_add(&new_timer->list, ¤t->signal->posix_timers);
662 spin_unlock_irq(¤t->sighand->siglock);
663
664 return 0;
665 /*
666 * In the case of the timer belonging to another task, after
667 * the task is unlocked, the timer is owned by the other task
668 * and may cease to exist at any time. Don't use or modify
669 * new_timer after the unlock call.
670 */
671out:
672 release_posix_timer(new_timer, it_id_set);
673 return error;
674}
675
676/*
677 * Locking issues: We need to protect the result of the id look up until
678 * we get the timer locked down so it is not deleted under us. The
679 * removal is done under the idr spinlock so we use that here to bridge
680 * the find to the timer lock. To avoid a dead lock, the timer id MUST
681 * be release with out holding the timer lock.
682 */
683static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
684{
685 struct k_itimer *timr;
686
687 /*
688 * timer_t could be any type >= int and we want to make sure any
689 * @timer_id outside positive int range fails lookup.
690 */
691 if ((unsigned long long)timer_id > INT_MAX)
692 return NULL;
693
694 rcu_read_lock();
695 timr = posix_timer_by_id(timer_id);
696 if (timr) {
697 spin_lock_irqsave(&timr->it_lock, *flags);
698 if (timr->it_signal == current->signal) {
699 rcu_read_unlock();
700 return timr;
701 }
702 spin_unlock_irqrestore(&timr->it_lock, *flags);
703 }
704 rcu_read_unlock();
705
706 return NULL;
707}
708
709/*
710 * Get the time remaining on a POSIX.1b interval timer. This function
711 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
712 * mess with irq.
713 *
714 * We have a couple of messes to clean up here. First there is the case
715 * of a timer that has a requeue pending. These timers should appear to
716 * be in the timer list with an expiry as if we were to requeue them
717 * now.
718 *
719 * The second issue is the SIGEV_NONE timer which may be active but is
720 * not really ever put in the timer list (to save system resources).
721 * This timer may be expired, and if so, we will do it here. Otherwise
722 * it is the same as a requeue pending timer WRT to what we should
723 * report.
724 */
725static void
726common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
727{
728 ktime_t now, remaining, iv;
729 struct hrtimer *timer = &timr->it.real.timer;
730
731 memset(cur_setting, 0, sizeof(struct itimerspec));
732
733 iv = timr->it.real.interval;
734
735 /* interval timer ? */
736 if (iv.tv64)
737 cur_setting->it_interval = ktime_to_timespec(iv);
738 else if (!hrtimer_active(timer) &&
739 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
740 return;
741
742 now = timer->base->get_time();
743
744 /*
745 * When a requeue is pending or this is a SIGEV_NONE
746 * timer move the expiry time forward by intervals, so
747 * expiry is > now.
748 */
749 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
750 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
751 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
752
753 remaining = ktime_sub(hrtimer_get_expires(timer), now);
754 /* Return 0 only, when the timer is expired and not pending */
755 if (remaining.tv64 <= 0) {
756 /*
757 * A single shot SIGEV_NONE timer must return 0, when
758 * it is expired !
759 */
760 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
761 cur_setting->it_value.tv_nsec = 1;
762 } else
763 cur_setting->it_value = ktime_to_timespec(remaining);
764}
765
766/* Get the time remaining on a POSIX.1b interval timer. */
767SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
768 struct itimerspec __user *, setting)
769{
770 struct itimerspec cur_setting;
771 struct k_itimer *timr;
772 struct k_clock *kc;
773 unsigned long flags;
774 int ret = 0;
775
776 timr = lock_timer(timer_id, &flags);
777 if (!timr)
778 return -EINVAL;
779
780 kc = clockid_to_kclock(timr->it_clock);
781 if (WARN_ON_ONCE(!kc || !kc->timer_get))
782 ret = -EINVAL;
783 else
784 kc->timer_get(timr, &cur_setting);
785
786 unlock_timer(timr, flags);
787
788 if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
789 return -EFAULT;
790
791 return ret;
792}
793
794/*
795 * Get the number of overruns of a POSIX.1b interval timer. This is to
796 * be the overrun of the timer last delivered. At the same time we are
797 * accumulating overruns on the next timer. The overrun is frozen when
798 * the signal is delivered, either at the notify time (if the info block
799 * is not queued) or at the actual delivery time (as we are informed by
800 * the call back to do_schedule_next_timer(). So all we need to do is
801 * to pick up the frozen overrun.
802 */
803SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
804{
805 struct k_itimer *timr;
806 int overrun;
807 unsigned long flags;
808
809 timr = lock_timer(timer_id, &flags);
810 if (!timr)
811 return -EINVAL;
812
813 overrun = timr->it_overrun_last;
814 unlock_timer(timr, flags);
815
816 return overrun;
817}
818
819/* Set a POSIX.1b interval timer. */
820/* timr->it_lock is taken. */
821static int
822common_timer_set(struct k_itimer *timr, int flags,
823 struct itimerspec *new_setting, struct itimerspec *old_setting)
824{
825 struct hrtimer *timer = &timr->it.real.timer;
826 enum hrtimer_mode mode;
827
828 if (old_setting)
829 common_timer_get(timr, old_setting);
830
831 /* disable the timer */
832 timr->it.real.interval.tv64 = 0;
833 /*
834 * careful here. If smp we could be in the "fire" routine which will
835 * be spinning as we hold the lock. But this is ONLY an SMP issue.
836 */
837 if (hrtimer_try_to_cancel(timer) < 0)
838 return TIMER_RETRY;
839
840 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
841 ~REQUEUE_PENDING;
842 timr->it_overrun_last = 0;
843
844 /* switch off the timer when it_value is zero */
845 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
846 return 0;
847
848 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
849 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
850 timr->it.real.timer.function = posix_timer_fn;
851
852 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
853
854 /* Convert interval */
855 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
856
857 /* SIGEV_NONE timers are not queued ! See common_timer_get */
858 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
859 /* Setup correct expiry time for relative timers */
860 if (mode == HRTIMER_MODE_REL) {
861 hrtimer_add_expires(timer, timer->base->get_time());
862 }
863 return 0;
864 }
865
866 hrtimer_start_expires(timer, mode);
867 return 0;
868}
869
870/* Set a POSIX.1b interval timer */
871SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
872 const struct itimerspec __user *, new_setting,
873 struct itimerspec __user *, old_setting)
874{
875 struct k_itimer *timr;
876 struct itimerspec new_spec, old_spec;
877 int error = 0;
878 unsigned long flag;
879 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
880 struct k_clock *kc;
881
882 if (!new_setting)
883 return -EINVAL;
884
885 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
886 return -EFAULT;
887
888 if (!timespec_valid(&new_spec.it_interval) ||
889 !timespec_valid(&new_spec.it_value))
890 return -EINVAL;
891retry:
892 timr = lock_timer(timer_id, &flag);
893 if (!timr)
894 return -EINVAL;
895
896 kc = clockid_to_kclock(timr->it_clock);
897 if (WARN_ON_ONCE(!kc || !kc->timer_set))
898 error = -EINVAL;
899 else
900 error = kc->timer_set(timr, flags, &new_spec, rtn);
901
902 unlock_timer(timr, flag);
903 if (error == TIMER_RETRY) {
904 rtn = NULL; // We already got the old time...
905 goto retry;
906 }
907
908 if (old_setting && !error &&
909 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
910 error = -EFAULT;
911
912 return error;
913}
914
915static int common_timer_del(struct k_itimer *timer)
916{
917 timer->it.real.interval.tv64 = 0;
918
919 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
920 return TIMER_RETRY;
921 return 0;
922}
923
924static inline int timer_delete_hook(struct k_itimer *timer)
925{
926 struct k_clock *kc = clockid_to_kclock(timer->it_clock);
927
928 if (WARN_ON_ONCE(!kc || !kc->timer_del))
929 return -EINVAL;
930 return kc->timer_del(timer);
931}
932
933/* Delete a POSIX.1b interval timer. */
934SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
935{
936 struct k_itimer *timer;
937 unsigned long flags;
938
939retry_delete:
940 timer = lock_timer(timer_id, &flags);
941 if (!timer)
942 return -EINVAL;
943
944 if (timer_delete_hook(timer) == TIMER_RETRY) {
945 unlock_timer(timer, flags);
946 goto retry_delete;
947 }
948
949 spin_lock(¤t->sighand->siglock);
950 list_del(&timer->list);
951 spin_unlock(¤t->sighand->siglock);
952 /*
953 * This keeps any tasks waiting on the spin lock from thinking
954 * they got something (see the lock code above).
955 */
956 timer->it_signal = NULL;
957
958 unlock_timer(timer, flags);
959 release_posix_timer(timer, IT_ID_SET);
960 return 0;
961}
962
963/*
964 * return timer owned by the process, used by exit_itimers
965 */
966static void itimer_delete(struct k_itimer *timer)
967{
968 unsigned long flags;
969
970retry_delete:
971 spin_lock_irqsave(&timer->it_lock, flags);
972
973 if (timer_delete_hook(timer) == TIMER_RETRY) {
974 unlock_timer(timer, flags);
975 goto retry_delete;
976 }
977 list_del(&timer->list);
978 /*
979 * This keeps any tasks waiting on the spin lock from thinking
980 * they got something (see the lock code above).
981 */
982 timer->it_signal = NULL;
983
984 unlock_timer(timer, flags);
985 release_posix_timer(timer, IT_ID_SET);
986}
987
988/*
989 * This is called by do_exit or de_thread, only when there are no more
990 * references to the shared signal_struct.
991 */
992void exit_itimers(struct signal_struct *sig)
993{
994 struct k_itimer *tmr;
995
996 while (!list_empty(&sig->posix_timers)) {
997 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
998 itimer_delete(tmr);
999 }
1000}
1001
1002SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
1003 const struct timespec __user *, tp)
1004{
1005 struct k_clock *kc = clockid_to_kclock(which_clock);
1006 struct timespec new_tp;
1007
1008 if (!kc || !kc->clock_set)
1009 return -EINVAL;
1010
1011 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
1012 return -EFAULT;
1013
1014 return kc->clock_set(which_clock, &new_tp);
1015}
1016
1017SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
1018 struct timespec __user *,tp)
1019{
1020 struct k_clock *kc = clockid_to_kclock(which_clock);
1021 struct timespec kernel_tp;
1022 int error;
1023
1024 if (!kc)
1025 return -EINVAL;
1026
1027 error = kc->clock_get(which_clock, &kernel_tp);
1028
1029 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
1030 error = -EFAULT;
1031
1032 return error;
1033}
1034
1035SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
1036 struct timex __user *, utx)
1037{
1038 struct k_clock *kc = clockid_to_kclock(which_clock);
1039 struct timex ktx;
1040 int err;
1041
1042 if (!kc)
1043 return -EINVAL;
1044 if (!kc->clock_adj)
1045 return -EOPNOTSUPP;
1046
1047 if (copy_from_user(&ktx, utx, sizeof(ktx)))
1048 return -EFAULT;
1049
1050 err = kc->clock_adj(which_clock, &ktx);
1051
1052 if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
1053 return -EFAULT;
1054
1055 return err;
1056}
1057
1058SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
1059 struct timespec __user *, tp)
1060{
1061 struct k_clock *kc = clockid_to_kclock(which_clock);
1062 struct timespec rtn_tp;
1063 int error;
1064
1065 if (!kc)
1066 return -EINVAL;
1067
1068 error = kc->clock_getres(which_clock, &rtn_tp);
1069
1070 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
1071 error = -EFAULT;
1072
1073 return error;
1074}
1075
1076/*
1077 * nanosleep for monotonic and realtime clocks
1078 */
1079static int common_nsleep(const clockid_t which_clock, int flags,
1080 struct timespec *tsave, struct timespec __user *rmtp)
1081{
1082 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
1083 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1084 which_clock);
1085}
1086
1087SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1088 const struct timespec __user *, rqtp,
1089 struct timespec __user *, rmtp)
1090{
1091 struct k_clock *kc = clockid_to_kclock(which_clock);
1092 struct timespec t;
1093
1094 if (!kc)
1095 return -EINVAL;
1096 if (!kc->nsleep)
1097 return -ENANOSLEEP_NOTSUP;
1098
1099 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
1100 return -EFAULT;
1101
1102 if (!timespec_valid(&t))
1103 return -EINVAL;
1104
1105 return kc->nsleep(which_clock, flags, &t, rmtp);
1106}
1107
1108/*
1109 * This will restart clock_nanosleep. This is required only by
1110 * compat_clock_nanosleep_restart for now.
1111 */
1112long clock_nanosleep_restart(struct restart_block *restart_block)
1113{
1114 clockid_t which_clock = restart_block->nanosleep.clockid;
1115 struct k_clock *kc = clockid_to_kclock(which_clock);
1116
1117 if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))
1118 return -EINVAL;
1119
1120 return kc->nsleep_restart(restart_block);
1121}