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