blob: 197208b3aa2ad837517d27662e5bacaafd75258b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/smp_lock.h>
35#include <linux/interrupt.h>
36#include <linux/slab.h>
37#include <linux/time.h>
38
39#include <asm/uaccess.h>
40#include <asm/semaphore.h>
41#include <linux/list.h>
42#include <linux/init.h>
43#include <linux/compiler.h>
44#include <linux/idr.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/module.h>
50
Linus Torvalds1da177e2005-04-16 15:20:36 -070051/*
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 */
72static kmem_cache_t *posix_timers_cache;
73static struct idr posix_timers_id;
74static DEFINE_SPINLOCK(idr_lock);
75
76/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * 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/*
87 * The timer ID is turned into a timer address by idr_find().
88 * Verifying a valid ID consists of:
89 *
90 * a) checking that idr_find() returns other than -1.
91 * b) checking that the timer id matches the one in the timer itself.
92 * c) that the timer owner is in the callers thread group.
93 */
94
95/*
96 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
97 * to implement others. This structure defines the various
98 * clocks and allows the possibility of adding others. We
99 * provide an interface to add clocks to the table and expect
100 * the "arch" code to add at least one clock that is high
101 * resolution. Here we define the standard CLOCK_REALTIME as a
102 * 1/HZ resolution clock.
103 *
104 * RESOLUTION: Clock resolution is used to round up timer and interval
105 * times, NOT to report clock times, which are reported with as
106 * much resolution as the system can muster. In some cases this
107 * resolution may depend on the underlying clock hardware and
108 * may not be quantifiable until run time, and only then is the
109 * necessary code is written. The standard says we should say
110 * something about this issue in the documentation...
111 *
112 * FUNCTIONS: The CLOCKs structure defines possible functions to handle
113 * various clock functions. For clocks that use the standard
114 * system timer code these entries should be NULL. This will
115 * allow dispatch without the overhead of indirect function
116 * calls. CLOCKS that depend on other sources (e.g. WWV or GPS)
117 * must supply functions here, even if the function just returns
118 * ENOSYS. The standard POSIX timer management code assumes the
119 * following: 1.) The k_itimer struct (sched.h) is used for the
120 * timer. 2.) The list, it_lock, it_clock, it_id and it_process
121 * fields are not modified by timer code.
122 *
123 * At this time all functions EXCEPT clock_nanosleep can be
124 * redirected by the CLOCKS structure. Clock_nanosleep is in
125 * there, but the code ignores it.
126 *
127 * Permissions: It is assumed that the clock_settime() function defined
128 * for each clock will take care of permission checks. Some
129 * clocks may be set able by any user (i.e. local process
130 * clocks) others not. Currently the only set able clock we
131 * have is CLOCK_REALTIME and its high res counter part, both of
132 * which we beg off on and pass to do_sys_settimeofday().
133 */
134
135static struct k_clock posix_clocks[MAX_CLOCKS];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800137/*
138 * These ones are defined below.
139 */
140static int common_nsleep(const clockid_t, int flags, struct timespec *t,
141 struct timespec __user *rmtp);
142static void common_timer_get(struct k_itimer *, struct itimerspec *);
143static int common_timer_set(struct k_itimer *, int,
144 struct itimerspec *, struct itimerspec *);
145static int common_timer_del(struct k_itimer *timer);
146
147static int posix_timer_fn(void *data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags);
150
151static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
152{
153 spin_unlock_irqrestore(&timr->it_lock, flags);
154}
155
156/*
157 * Call the k_clock hook function if non-null, or the default function.
158 */
159#define CLOCK_DISPATCH(clock, call, arglist) \
160 ((clock) < 0 ? posix_cpu_##call arglist : \
161 (posix_clocks[clock].call != NULL \
162 ? (*posix_clocks[clock].call) arglist : common_##call arglist))
163
164/*
165 * Default clock hook functions when the struct k_clock passed
166 * to register_posix_clock leaves a function pointer null.
167 *
168 * The function common_CALL is the default implementation for
169 * the function pointer CALL in struct k_clock.
170 */
171
Thomas Gleixnera924b042006-01-09 20:52:27 -0800172static inline int common_clock_getres(const clockid_t which_clock,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 struct timespec *tp)
174{
175 tp->tv_sec = 0;
176 tp->tv_nsec = posix_clocks[which_clock].res;
177 return 0;
178}
179
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800180/*
181 * Get real time for posix timers
182 */
183static int common_clock_get(clockid_t which_clock, struct timespec *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800185 ktime_get_real_ts(tp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 return 0;
187}
188
Thomas Gleixnera924b042006-01-09 20:52:27 -0800189static inline int common_clock_set(const clockid_t which_clock,
190 struct timespec *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
192 return do_sys_settimeofday(tp, NULL);
193}
194
Arjan van de Ven858119e2006-01-14 13:20:43 -0800195static int common_timer_create(struct k_itimer *new_timer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800197 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock);
198 new_timer->it.real.timer.data = new_timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 new_timer->it.real.timer.function = posix_timer_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 return 0;
201}
202
203/*
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800204 * Return nonzero if we know a priori this clockid_t value is bogus.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 */
Thomas Gleixnera924b042006-01-09 20:52:27 -0800206static inline int invalid_clockid(const clockid_t which_clock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
208 if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */
209 return 0;
210 if ((unsigned) which_clock >= MAX_CLOCKS)
211 return 1;
212 if (posix_clocks[which_clock].clock_getres != NULL)
213 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 if (posix_clocks[which_clock].res != 0)
215 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 return 1;
217}
218
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800219/*
220 * Get monotonic time for posix timers
221 */
222static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
223{
224 ktime_get_ts(tp);
225 return 0;
226}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228/*
229 * Initialize everything, well, just everything in Posix clocks/timers ;)
230 */
231static __init int init_posix_timers(void)
232{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800233 struct k_clock clock_realtime = {
234 .clock_getres = hrtimer_get_res,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 };
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800236 struct k_clock clock_monotonic = {
237 .clock_getres = hrtimer_get_res,
238 .clock_get = posix_ktime_get_ts,
239 .clock_set = do_posix_clock_nosettime,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 };
241
242 register_posix_clock(CLOCK_REALTIME, &clock_realtime);
243 register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
244
245 posix_timers_cache = kmem_cache_create("posix_timers_cache",
246 sizeof (struct k_itimer), 0, 0, NULL, NULL);
247 idr_init(&posix_timers_id);
248 return 0;
249}
250
251__initcall(init_posix_timers);
252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253static void schedule_next_timer(struct k_itimer *timr)
254{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800255 if (timr->it.real.interval.tv64 == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 return;
257
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800258 timr->it_overrun += hrtimer_forward(&timr->it.real.timer,
259 timr->it.real.interval);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 timr->it_overrun_last = timr->it_overrun;
261 timr->it_overrun = -1;
262 ++timr->it_requeue_pending;
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800263 hrtimer_restart(&timr->it.real.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264}
265
266/*
267 * This function is exported for use by the signal deliver code. It is
268 * called just prior to the info block being released and passes that
269 * block to us. It's function is to update the overrun entry AND to
270 * restart the timer. It should only be called if the timer is to be
271 * restarted (i.e. we have flagged this in the sys_private entry of the
272 * info block).
273 *
274 * To protect aginst the timer going away while the interrupt is queued,
275 * we require that the it_requeue_pending flag be set.
276 */
277void do_schedule_next_timer(struct siginfo *info)
278{
279 struct k_itimer *timr;
280 unsigned long flags;
281
282 timr = lock_timer(info->si_tid, &flags);
283
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800284 if (timr && timr->it_requeue_pending == info->si_sys_private) {
285 if (timr->it_clock < 0)
286 posix_cpu_timer_schedule(timr);
287 else
288 schedule_next_timer(timr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800290 info->si_overrun = timr->it_overrun_last;
291 }
292
293 unlock_timer(timr, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294}
295
296int posix_timer_event(struct k_itimer *timr,int si_private)
297{
298 memset(&timr->sigq->info, 0, sizeof(siginfo_t));
299 timr->sigq->info.si_sys_private = si_private;
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800300 /* Send signal to the process that owns this timer.*/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
302 timr->sigq->info.si_signo = timr->it_sigev_signo;
303 timr->sigq->info.si_errno = 0;
304 timr->sigq->info.si_code = SI_TIMER;
305 timr->sigq->info.si_tid = timr->it_id;
306 timr->sigq->info.si_value = timr->it_sigev_value;
Oleg Nesterove752dd62005-09-06 15:17:42 -0700307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
Oleg Nesterove752dd62005-09-06 15:17:42 -0700309 struct task_struct *leader;
310 int ret = send_sigqueue(timr->it_sigev_signo, timr->sigq,
311 timr->it_process);
312
313 if (likely(ret >= 0))
314 return ret;
315
316 timr->it_sigev_notify = SIGEV_SIGNAL;
317 leader = timr->it_process->group_leader;
318 put_task_struct(timr->it_process);
319 timr->it_process = leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 }
Oleg Nesterove752dd62005-09-06 15:17:42 -0700321
322 return send_group_sigqueue(timr->it_sigev_signo, timr->sigq,
323 timr->it_process);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324}
325EXPORT_SYMBOL_GPL(posix_timer_event);
326
327/*
328 * This function gets called when a POSIX.1b interval timer expires. It
329 * is used as a callback from the kernel internal timer. The
330 * run_timer_list code ALWAYS calls with interrupts on.
331
332 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
333 */
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800334static int posix_timer_fn(void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800336 struct k_itimer *timr = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 unsigned long flags;
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800338 int si_private = 0;
339 int ret = HRTIMER_NORESTART;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341 spin_lock_irqsave(&timr->it_lock, flags);
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800342
343 if (timr->it.real.interval.tv64 != 0)
344 si_private = ++timr->it_requeue_pending;
345
346 if (posix_timer_event(timr, si_private)) {
347 /*
348 * signal was not sent because of sig_ignor
349 * we will not get a call back to restart it AND
350 * it should be restarted.
351 */
352 if (timr->it.real.interval.tv64 != 0) {
353 timr->it_overrun +=
354 hrtimer_forward(&timr->it.real.timer,
355 timr->it.real.interval);
356 ret = HRTIMER_RESTART;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800360 unlock_timer(timr, flags);
361 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362}
363
Arjan van de Ven858119e2006-01-14 13:20:43 -0800364static struct task_struct * good_sigevent(sigevent_t * event)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365{
366 struct task_struct *rtn = current->group_leader;
367
368 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
369 (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) ||
370 rtn->tgid != current->tgid ||
371 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
372 return NULL;
373
374 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
375 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
376 return NULL;
377
378 return rtn;
379}
380
Thomas Gleixnera924b042006-01-09 20:52:27 -0800381void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382{
383 if ((unsigned) clock_id >= MAX_CLOCKS) {
384 printk("POSIX clock register failed for clock_id %d\n",
385 clock_id);
386 return;
387 }
388
389 posix_clocks[clock_id] = *new_clock;
390}
391EXPORT_SYMBOL_GPL(register_posix_clock);
392
393static struct k_itimer * alloc_posix_timer(void)
394{
395 struct k_itimer *tmr;
396 tmr = kmem_cache_alloc(posix_timers_cache, GFP_KERNEL);
397 if (!tmr)
398 return tmr;
399 memset(tmr, 0, sizeof (struct k_itimer));
400 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
401 kmem_cache_free(posix_timers_cache, tmr);
402 tmr = NULL;
403 }
404 return tmr;
405}
406
407#define IT_ID_SET 1
408#define IT_ID_NOT_SET 0
409static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
410{
411 if (it_id_set) {
412 unsigned long flags;
413 spin_lock_irqsave(&idr_lock, flags);
414 idr_remove(&posix_timers_id, tmr->it_id);
415 spin_unlock_irqrestore(&idr_lock, flags);
416 }
417 sigqueue_free(tmr->sigq);
418 if (unlikely(tmr->it_process) &&
419 tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
420 put_task_struct(tmr->it_process);
421 kmem_cache_free(posix_timers_cache, tmr);
422}
423
424/* Create a POSIX.1b interval timer. */
425
426asmlinkage long
Thomas Gleixnera924b042006-01-09 20:52:27 -0800427sys_timer_create(const clockid_t which_clock,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 struct sigevent __user *timer_event_spec,
429 timer_t __user * created_timer_id)
430{
431 int error = 0;
432 struct k_itimer *new_timer = NULL;
433 int new_timer_id;
434 struct task_struct *process = NULL;
435 unsigned long flags;
436 sigevent_t event;
437 int it_id_set = IT_ID_NOT_SET;
438
439 if (invalid_clockid(which_clock))
440 return -EINVAL;
441
442 new_timer = alloc_posix_timer();
443 if (unlikely(!new_timer))
444 return -EAGAIN;
445
446 spin_lock_init(&new_timer->it_lock);
447 retry:
448 if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) {
449 error = -EAGAIN;
450 goto out;
451 }
452 spin_lock_irq(&idr_lock);
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800453 error = idr_get_new(&posix_timers_id, (void *) new_timer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 &new_timer_id);
455 spin_unlock_irq(&idr_lock);
456 if (error == -EAGAIN)
457 goto retry;
458 else if (error) {
459 /*
460 * Wierd looking, but we return EAGAIN if the IDR is
461 * full (proper POSIX return value for this)
462 */
463 error = -EAGAIN;
464 goto out;
465 }
466
467 it_id_set = IT_ID_SET;
468 new_timer->it_id = (timer_t) new_timer_id;
469 new_timer->it_clock = which_clock;
470 new_timer->it_overrun = -1;
471 error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
472 if (error)
473 goto out;
474
475 /*
476 * return the timer_id now. The next step is hard to
477 * back out if there is an error.
478 */
479 if (copy_to_user(created_timer_id,
480 &new_timer_id, sizeof (new_timer_id))) {
481 error = -EFAULT;
482 goto out;
483 }
484 if (timer_event_spec) {
485 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
486 error = -EFAULT;
487 goto out;
488 }
489 new_timer->it_sigev_notify = event.sigev_notify;
490 new_timer->it_sigev_signo = event.sigev_signo;
491 new_timer->it_sigev_value = event.sigev_value;
492
493 read_lock(&tasklist_lock);
494 if ((process = good_sigevent(&event))) {
495 /*
496 * We may be setting up this process for another
497 * thread. It may be exiting. To catch this
498 * case the we check the PF_EXITING flag. If
499 * the flag is not set, the siglock will catch
500 * him before it is too late (in exit_itimers).
501 *
502 * The exec case is a bit more invloved but easy
503 * to code. If the process is in our thread
504 * group (and it must be or we would not allow
505 * it here) and is doing an exec, it will cause
506 * us to be killed. In this case it will wait
507 * for us to die which means we can finish this
508 * linkage with our last gasp. I.e. no code :)
509 */
510 spin_lock_irqsave(&process->sighand->siglock, flags);
511 if (!(process->flags & PF_EXITING)) {
512 new_timer->it_process = process;
513 list_add(&new_timer->list,
514 &process->signal->posix_timers);
515 spin_unlock_irqrestore(&process->sighand->siglock, flags);
516 if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
517 get_task_struct(process);
518 } else {
519 spin_unlock_irqrestore(&process->sighand->siglock, flags);
520 process = NULL;
521 }
522 }
523 read_unlock(&tasklist_lock);
524 if (!process) {
525 error = -EINVAL;
526 goto out;
527 }
528 } else {
529 new_timer->it_sigev_notify = SIGEV_SIGNAL;
530 new_timer->it_sigev_signo = SIGALRM;
531 new_timer->it_sigev_value.sival_int = new_timer->it_id;
532 process = current->group_leader;
533 spin_lock_irqsave(&process->sighand->siglock, flags);
534 new_timer->it_process = process;
535 list_add(&new_timer->list, &process->signal->posix_timers);
536 spin_unlock_irqrestore(&process->sighand->siglock, flags);
537 }
538
539 /*
540 * In the case of the timer belonging to another task, after
541 * the task is unlocked, the timer is owned by the other task
542 * and may cease to exist at any time. Don't use or modify
543 * new_timer after the unlock call.
544 */
545
546out:
547 if (error)
548 release_posix_timer(new_timer, it_id_set);
549
550 return error;
551}
552
553/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 * Locking issues: We need to protect the result of the id look up until
555 * we get the timer locked down so it is not deleted under us. The
556 * removal is done under the idr spinlock so we use that here to bridge
557 * the find to the timer lock. To avoid a dead lock, the timer id MUST
558 * be release with out holding the timer lock.
559 */
560static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags)
561{
562 struct k_itimer *timr;
563 /*
564 * Watch out here. We do a irqsave on the idr_lock and pass the
565 * flags part over to the timer lock. Must not let interrupts in
566 * while we are moving the lock.
567 */
568
569 spin_lock_irqsave(&idr_lock, *flags);
570 timr = (struct k_itimer *) idr_find(&posix_timers_id, (int) timer_id);
571 if (timr) {
572 spin_lock(&timr->it_lock);
573 spin_unlock(&idr_lock);
574
575 if ((timr->it_id != timer_id) || !(timr->it_process) ||
576 timr->it_process->tgid != current->tgid) {
577 unlock_timer(timr, *flags);
578 timr = NULL;
579 }
580 } else
581 spin_unlock_irqrestore(&idr_lock, *flags);
582
583 return timr;
584}
585
586/*
587 * Get the time remaining on a POSIX.1b interval timer. This function
588 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
589 * mess with irq.
590 *
591 * We have a couple of messes to clean up here. First there is the case
592 * of a timer that has a requeue pending. These timers should appear to
593 * be in the timer list with an expiry as if we were to requeue them
594 * now.
595 *
596 * The second issue is the SIGEV_NONE timer which may be active but is
597 * not really ever put in the timer list (to save system resources).
598 * This timer may be expired, and if so, we will do it here. Otherwise
599 * it is the same as a requeue pending timer WRT to what we should
600 * report.
601 */
602static void
603common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
604{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800605 ktime_t remaining;
606 struct hrtimer *timer = &timr->it.real.timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800608 memset(cur_setting, 0, sizeof(struct itimerspec));
609 remaining = hrtimer_get_remaining(timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800611 /* Time left ? or timer pending */
612 if (remaining.tv64 > 0 || hrtimer_active(timer))
613 goto calci;
614 /* interval timer ? */
615 if (timr->it.real.interval.tv64 == 0)
616 return;
617 /*
618 * When a requeue is pending or this is a SIGEV_NONE timer
619 * move the expiry time forward by intervals, so expiry is >
620 * now.
621 */
622 if (timr->it_requeue_pending & REQUEUE_PENDING ||
623 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
624 timr->it_overrun +=
625 hrtimer_forward(timer, timr->it.real.interval);
626 remaining = hrtimer_get_remaining(timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 }
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800628 calci:
629 /* interval timer ? */
630 if (timr->it.real.interval.tv64 != 0)
631 cur_setting->it_interval =
632 ktime_to_timespec(timr->it.real.interval);
633 /* Return 0 only, when the timer is expired and not pending */
634 if (remaining.tv64 <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 cur_setting->it_value.tv_nsec = 1;
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800636 else
637 cur_setting->it_value = ktime_to_timespec(remaining);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638}
639
640/* Get the time remaining on a POSIX.1b interval timer. */
641asmlinkage long
642sys_timer_gettime(timer_t timer_id, struct itimerspec __user *setting)
643{
644 struct k_itimer *timr;
645 struct itimerspec cur_setting;
646 unsigned long flags;
647
648 timr = lock_timer(timer_id, &flags);
649 if (!timr)
650 return -EINVAL;
651
652 CLOCK_DISPATCH(timr->it_clock, timer_get, (timr, &cur_setting));
653
654 unlock_timer(timr, flags);
655
656 if (copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
657 return -EFAULT;
658
659 return 0;
660}
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800661
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662/*
663 * Get the number of overruns of a POSIX.1b interval timer. This is to
664 * be the overrun of the timer last delivered. At the same time we are
665 * accumulating overruns on the next timer. The overrun is frozen when
666 * the signal is delivered, either at the notify time (if the info block
667 * is not queued) or at the actual delivery time (as we are informed by
668 * the call back to do_schedule_next_timer(). So all we need to do is
669 * to pick up the frozen overrun.
670 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671asmlinkage long
672sys_timer_getoverrun(timer_t timer_id)
673{
674 struct k_itimer *timr;
675 int overrun;
676 long flags;
677
678 timr = lock_timer(timer_id, &flags);
679 if (!timr)
680 return -EINVAL;
681
682 overrun = timr->it_overrun_last;
683 unlock_timer(timr, flags);
684
685 return overrun;
686}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
688/* Set a POSIX.1b interval timer. */
689/* timr->it_lock is taken. */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800690static int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691common_timer_set(struct k_itimer *timr, int flags,
692 struct itimerspec *new_setting, struct itimerspec *old_setting)
693{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800694 struct hrtimer *timer = &timr->it.real.timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695
696 if (old_setting)
697 common_timer_get(timr, old_setting);
698
699 /* disable the timer */
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800700 timr->it.real.interval.tv64 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 /*
702 * careful here. If smp we could be in the "fire" routine which will
703 * be spinning as we hold the lock. But this is ONLY an SMP issue.
704 */
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800705 if (hrtimer_try_to_cancel(timer) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 return TIMER_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707
708 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
709 ~REQUEUE_PENDING;
710 timr->it_overrun_last = 0;
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800711
712 /* switch off the timer when it_value is zero */
713 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800716 /* Posix madness. Only absolute CLOCK_REALTIME timers
717 * are affected by clock sets. So we must reiniatilize
718 * the timer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 */
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800720 if (timr->it_clock == CLOCK_REALTIME && (flags & TIMER_ABSTIME))
721 hrtimer_rebase(timer, CLOCK_REALTIME);
722 else
723 hrtimer_rebase(timer, CLOCK_MONOTONIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800725 timer->expires = timespec_to_ktime(new_setting->it_value);
726
727 /* Convert interval */
728 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
729
730 /* SIGEV_NONE timers are not queued ! See common_timer_get */
731 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
732 return 0;
733
734 hrtimer_start(timer, timer->expires, (flags & TIMER_ABSTIME) ?
735 HRTIMER_ABS : HRTIMER_REL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 return 0;
737}
738
739/* Set a POSIX.1b interval timer */
740asmlinkage long
741sys_timer_settime(timer_t timer_id, int flags,
742 const struct itimerspec __user *new_setting,
743 struct itimerspec __user *old_setting)
744{
745 struct k_itimer *timr;
746 struct itimerspec new_spec, old_spec;
747 int error = 0;
748 long flag;
749 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
750
751 if (!new_setting)
752 return -EINVAL;
753
754 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
755 return -EFAULT;
756
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800757 if (!timespec_valid(&new_spec.it_interval) ||
758 !timespec_valid(&new_spec.it_value))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 return -EINVAL;
760retry:
761 timr = lock_timer(timer_id, &flag);
762 if (!timr)
763 return -EINVAL;
764
765 error = CLOCK_DISPATCH(timr->it_clock, timer_set,
766 (timr, flags, &new_spec, rtn));
767
768 unlock_timer(timr, flag);
769 if (error == TIMER_RETRY) {
770 rtn = NULL; // We already got the old time...
771 goto retry;
772 }
773
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800774 if (old_setting && !error &&
775 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 error = -EFAULT;
777
778 return error;
779}
780
781static inline int common_timer_del(struct k_itimer *timer)
782{
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800783 timer->it.real.interval.tv64 = 0;
Oleg Nesterovf972be32005-06-23 00:09:00 -0700784
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800785 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 return TIMER_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 return 0;
788}
789
790static inline int timer_delete_hook(struct k_itimer *timer)
791{
792 return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer));
793}
794
795/* Delete a POSIX.1b interval timer. */
796asmlinkage long
797sys_timer_delete(timer_t timer_id)
798{
799 struct k_itimer *timer;
800 long flags;
801
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802retry_delete:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 timer = lock_timer(timer_id, &flags);
804 if (!timer)
805 return -EINVAL;
806
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800807 if (timer_delete_hook(timer) == TIMER_RETRY) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 unlock_timer(timer, flags);
809 goto retry_delete;
810 }
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800811
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 spin_lock(&current->sighand->siglock);
813 list_del(&timer->list);
814 spin_unlock(&current->sighand->siglock);
815 /*
816 * This keeps any tasks waiting on the spin lock from thinking
817 * they got something (see the lock code above).
818 */
819 if (timer->it_process) {
820 if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
821 put_task_struct(timer->it_process);
822 timer->it_process = NULL;
823 }
824 unlock_timer(timer, flags);
825 release_posix_timer(timer, IT_ID_SET);
826 return 0;
827}
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800828
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829/*
830 * return timer owned by the process, used by exit_itimers
831 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800832static void itimer_delete(struct k_itimer *timer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833{
834 unsigned long flags;
835
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836retry_delete:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 spin_lock_irqsave(&timer->it_lock, flags);
838
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800839 if (timer_delete_hook(timer) == TIMER_RETRY) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 unlock_timer(timer, flags);
841 goto retry_delete;
842 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 list_del(&timer->list);
844 /*
845 * This keeps any tasks waiting on the spin lock from thinking
846 * they got something (see the lock code above).
847 */
848 if (timer->it_process) {
849 if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
850 put_task_struct(timer->it_process);
851 timer->it_process = NULL;
852 }
853 unlock_timer(timer, flags);
854 release_posix_timer(timer, IT_ID_SET);
855}
856
857/*
Roland McGrath25f407f2005-10-21 15:03:29 -0700858 * This is called by do_exit or de_thread, only when there are no more
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 * references to the shared signal_struct.
860 */
861void exit_itimers(struct signal_struct *sig)
862{
863 struct k_itimer *tmr;
864
865 while (!list_empty(&sig->posix_timers)) {
866 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
867 itimer_delete(tmr);
868 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869}
870
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800871/* Not available / possible... functions */
Thomas Gleixnera924b042006-01-09 20:52:27 -0800872int do_posix_clock_nosettime(const clockid_t clockid, struct timespec *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873{
874 return -EINVAL;
875}
876EXPORT_SYMBOL_GPL(do_posix_clock_nosettime);
877
878int do_posix_clock_notimer_create(struct k_itimer *timer)
879{
880 return -EINVAL;
881}
882EXPORT_SYMBOL_GPL(do_posix_clock_notimer_create);
883
Thomas Gleixnera924b042006-01-09 20:52:27 -0800884int do_posix_clock_nonanosleep(const clockid_t clock, int flags,
Thomas Gleixner97735f22006-01-09 20:52:37 -0800885 struct timespec *t, struct timespec __user *r)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886{
887#ifndef ENOTSUP
888 return -EOPNOTSUPP; /* aka ENOTSUP in userland for POSIX */
889#else /* parisc does define it separately. */
890 return -ENOTSUP;
891#endif
892}
893EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep);
894
Thomas Gleixnera924b042006-01-09 20:52:27 -0800895asmlinkage long sys_clock_settime(const clockid_t which_clock,
896 const struct timespec __user *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897{
898 struct timespec new_tp;
899
900 if (invalid_clockid(which_clock))
901 return -EINVAL;
902 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
903 return -EFAULT;
904
905 return CLOCK_DISPATCH(which_clock, clock_set, (which_clock, &new_tp));
906}
907
908asmlinkage long
Thomas Gleixnera924b042006-01-09 20:52:27 -0800909sys_clock_gettime(const clockid_t which_clock, struct timespec __user *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910{
911 struct timespec kernel_tp;
912 int error;
913
914 if (invalid_clockid(which_clock))
915 return -EINVAL;
916 error = CLOCK_DISPATCH(which_clock, clock_get,
917 (which_clock, &kernel_tp));
918 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
919 error = -EFAULT;
920
921 return error;
922
923}
924
925asmlinkage long
Thomas Gleixnera924b042006-01-09 20:52:27 -0800926sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927{
928 struct timespec rtn_tp;
929 int error;
930
931 if (invalid_clockid(which_clock))
932 return -EINVAL;
933
934 error = CLOCK_DISPATCH(which_clock, clock_getres,
935 (which_clock, &rtn_tp));
936
937 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) {
938 error = -EFAULT;
939 }
940
941 return error;
942}
943
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944/*
Thomas Gleixner97735f22006-01-09 20:52:37 -0800945 * nanosleep for monotonic and realtime clocks
946 */
947static int common_nsleep(const clockid_t which_clock, int flags,
948 struct timespec *tsave, struct timespec __user *rmtp)
949{
950 int mode = flags & TIMER_ABSTIME ? HRTIMER_ABS : HRTIMER_REL;
951 int clockid = which_clock;
952
953 switch (which_clock) {
954 case CLOCK_REALTIME:
955 /* Posix madness. Only absolute timers on clock realtime
956 are affected by clock set. */
Thomas Gleixnerbecf8b52006-01-09 20:52:38 -0800957 if (mode != HRTIMER_ABS)
Thomas Gleixner97735f22006-01-09 20:52:37 -0800958 clockid = CLOCK_MONOTONIC;
959 case CLOCK_MONOTONIC:
960 break;
961 default:
962 return -EINVAL;
963 }
964 return hrtimer_nanosleep(tsave, rmtp, mode, clockid);
965}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966
967asmlinkage long
Thomas Gleixnera924b042006-01-09 20:52:27 -0800968sys_clock_nanosleep(const clockid_t which_clock, int flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 const struct timespec __user *rqtp,
970 struct timespec __user *rmtp)
971{
972 struct timespec t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
974 if (invalid_clockid(which_clock))
975 return -EINVAL;
976
977 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
978 return -EFAULT;
979
Thomas Gleixner5f82b2b2006-01-09 20:52:29 -0800980 if (!timespec_valid(&t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 return -EINVAL;
982
Thomas Gleixner97735f22006-01-09 20:52:37 -0800983 return CLOCK_DISPATCH(which_clock, nsleep,
984 (which_clock, flags, &t, rmtp));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985}