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1da177e4 1/*
f30c2269 2 * linux/kernel/posix-timers.c
1da177e4
LT
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>
1da177e4
LT
34#include <linux/interrupt.h>
35#include <linux/slab.h>
36#include <linux/time.h>
97d1f15b 37#include <linux/mutex.h>
1da177e4
LT
38
39#include <asm/uaccess.h>
1da177e4
LT
40#include <linux/list.h>
41#include <linux/init.h>
42#include <linux/compiler.h>
43#include <linux/idr.h>
44#include <linux/posix-timers.h>
45#include <linux/syscalls.h>
46#include <linux/wait.h>
47#include <linux/workqueue.h>
48#include <linux/module.h>
49
1da177e4
LT
50/*
51 * Management arrays for POSIX timers. Timers are kept in slab memory
52 * Timer ids are allocated by an external routine that keeps track of the
53 * id and the timer. The external interface is:
54 *
55 * void *idr_find(struct idr *idp, int id); to find timer_id <id>
56 * int idr_get_new(struct idr *idp, void *ptr); to get a new id and
57 * related it to <ptr>
58 * void idr_remove(struct idr *idp, int id); to release <id>
59 * void idr_init(struct idr *idp); to initialize <idp>
60 * which we supply.
61 * The idr_get_new *may* call slab for more memory so it must not be
62 * called under a spin lock. Likewise idr_remore may release memory
63 * (but it may be ok to do this under a lock...).
64 * idr_find is just a memory look up and is quite fast. A -1 return
65 * indicates that the requested id does not exist.
66 */
67
68/*
69 * Lets keep our timers in a slab cache :-)
70 */
e18b890b 71static struct kmem_cache *posix_timers_cache;
1da177e4
LT
72static struct idr posix_timers_id;
73static DEFINE_SPINLOCK(idr_lock);
74
1da177e4
LT
75/*
76 * we assume that the new SIGEV_THREAD_ID shares no bits with the other
77 * SIGEV values. Here we put out an error if this assumption fails.
78 */
79#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
80 ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
81#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
82#endif
83
65da528d
TG
84/*
85 * parisc wants ENOTSUP instead of EOPNOTSUPP
86 */
87#ifndef ENOTSUP
88# define ENANOSLEEP_NOTSUP EOPNOTSUPP
89#else
90# define ENANOSLEEP_NOTSUP ENOTSUP
91#endif
1da177e4
LT
92
93/*
94 * The timer ID is turned into a timer address by idr_find().
95 * Verifying a valid ID consists of:
96 *
97 * a) checking that idr_find() returns other than -1.
98 * b) checking that the timer id matches the one in the timer itself.
99 * c) that the timer owner is in the callers thread group.
100 */
101
102/*
103 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
104 * to implement others. This structure defines the various
105 * clocks and allows the possibility of adding others. We
106 * provide an interface to add clocks to the table and expect
107 * the "arch" code to add at least one clock that is high
108 * resolution. Here we define the standard CLOCK_REALTIME as a
109 * 1/HZ resolution clock.
110 *
111 * RESOLUTION: Clock resolution is used to round up timer and interval
112 * times, NOT to report clock times, which are reported with as
113 * much resolution as the system can muster. In some cases this
114 * resolution may depend on the underlying clock hardware and
115 * may not be quantifiable until run time, and only then is the
116 * necessary code is written. The standard says we should say
117 * something about this issue in the documentation...
118 *
119 * FUNCTIONS: The CLOCKs structure defines possible functions to handle
120 * various clock functions. For clocks that use the standard
121 * system timer code these entries should be NULL. This will
122 * allow dispatch without the overhead of indirect function
123 * calls. CLOCKS that depend on other sources (e.g. WWV or GPS)
124 * must supply functions here, even if the function just returns
125 * ENOSYS. The standard POSIX timer management code assumes the
126 * following: 1.) The k_itimer struct (sched.h) is used for the
27af4245 127 * timer. 2.) The list, it_lock, it_clock, it_id and it_pid
1da177e4
LT
128 * fields are not modified by timer code.
129 *
130 * At this time all functions EXCEPT clock_nanosleep can be
131 * redirected by the CLOCKS structure. Clock_nanosleep is in
132 * there, but the code ignores it.
133 *
134 * Permissions: It is assumed that the clock_settime() function defined
135 * for each clock will take care of permission checks. Some
136 * clocks may be set able by any user (i.e. local process
137 * clocks) others not. Currently the only set able clock we
138 * have is CLOCK_REALTIME and its high res counter part, both of
139 * which we beg off on and pass to do_sys_settimeofday().
140 */
141
142static struct k_clock posix_clocks[MAX_CLOCKS];
becf8b5d 143
1da177e4 144/*
becf8b5d 145 * These ones are defined below.
1da177e4 146 */
becf8b5d
TG
147static int common_nsleep(const clockid_t, int flags, struct timespec *t,
148 struct timespec __user *rmtp);
149static void common_timer_get(struct k_itimer *, struct itimerspec *);
150static int common_timer_set(struct k_itimer *, int,
151 struct itimerspec *, struct itimerspec *);
152static int common_timer_del(struct k_itimer *timer);
1da177e4 153
c9cb2e3d 154static enum hrtimer_restart posix_timer_fn(struct hrtimer *data);
1da177e4 155
20f33a03
NK
156static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
157
158#define lock_timer(tid, flags) \
159({ struct k_itimer *__timr; \
160 __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \
161 __timr; \
162})
1da177e4
LT
163
164static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
165{
166 spin_unlock_irqrestore(&timr->it_lock, flags);
167}
168
169/*
170 * Call the k_clock hook function if non-null, or the default function.
171 */
172#define CLOCK_DISPATCH(clock, call, arglist) \
173 ((clock) < 0 ? posix_cpu_##call arglist : \
174 (posix_clocks[clock].call != NULL \
175 ? (*posix_clocks[clock].call) arglist : common_##call arglist))
176
177/*
178 * Default clock hook functions when the struct k_clock passed
179 * to register_posix_clock leaves a function pointer null.
180 *
181 * The function common_CALL is the default implementation for
182 * the function pointer CALL in struct k_clock.
183 */
184
a924b04d 185static inline int common_clock_getres(const clockid_t which_clock,
1da177e4
LT
186 struct timespec *tp)
187{
188 tp->tv_sec = 0;
189 tp->tv_nsec = posix_clocks[which_clock].res;
190 return 0;
191}
192
becf8b5d
TG
193/*
194 * Get real time for posix timers
195 */
196static int common_clock_get(clockid_t which_clock, struct timespec *tp)
1da177e4 197{
becf8b5d 198 ktime_get_real_ts(tp);
1da177e4
LT
199 return 0;
200}
201
a924b04d 202static inline int common_clock_set(const clockid_t which_clock,
1e6d7679 203 const struct timespec *tp)
1da177e4
LT
204{
205 return do_sys_settimeofday(tp, NULL);
206}
207
858119e1 208static int common_timer_create(struct k_itimer *new_timer)
1da177e4 209{
7978672c 210 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
1da177e4
LT
211 return 0;
212}
213
3d44cc3e
TG
214static int no_timer_create(struct k_itimer *new_timer)
215{
216 return -EOPNOTSUPP;
217}
218
70d715fd
HS
219static int no_nsleep(const clockid_t which_clock, int flags,
220 struct timespec *tsave, struct timespec __user *rmtp)
221{
222 return -EOPNOTSUPP;
223}
224
1da177e4 225/*
becf8b5d 226 * Return nonzero if we know a priori this clockid_t value is bogus.
1da177e4 227 */
a924b04d 228static inline int invalid_clockid(const clockid_t which_clock)
1da177e4
LT
229{
230 if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */
231 return 0;
232 if ((unsigned) which_clock >= MAX_CLOCKS)
233 return 1;
234 if (posix_clocks[which_clock].clock_getres != NULL)
235 return 0;
1da177e4
LT
236 if (posix_clocks[which_clock].res != 0)
237 return 0;
1da177e4
LT
238 return 1;
239}
240
becf8b5d
TG
241/*
242 * Get monotonic time for posix timers
243 */
244static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
245{
246 ktime_get_ts(tp);
247 return 0;
248}
1da177e4 249
2d42244a
JS
250/*
251 * Get monotonic time for posix timers
252 */
253static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
254{
255 getrawmonotonic(tp);
256 return 0;
257}
258
da15cfda
JS
259
260static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
261{
262 *tp = current_kernel_time();
263 return 0;
264}
265
266static int posix_get_monotonic_coarse(clockid_t which_clock,
267 struct timespec *tp)
268{
269 *tp = get_monotonic_coarse();
270 return 0;
271}
272
6622e670 273static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
da15cfda
JS
274{
275 *tp = ktime_to_timespec(KTIME_LOW_RES);
276 return 0;
277}
1da177e4
LT
278/*
279 * Initialize everything, well, just everything in Posix clocks/timers ;)
280 */
281static __init int init_posix_timers(void)
282{
becf8b5d
TG
283 struct k_clock clock_realtime = {
284 .clock_getres = hrtimer_get_res,
1da177e4 285 };
becf8b5d
TG
286 struct k_clock clock_monotonic = {
287 .clock_getres = hrtimer_get_res,
288 .clock_get = posix_ktime_get_ts,
289 .clock_set = do_posix_clock_nosettime,
1da177e4 290 };
2d42244a
JS
291 struct k_clock clock_monotonic_raw = {
292 .clock_getres = hrtimer_get_res,
293 .clock_get = posix_get_monotonic_raw,
294 .clock_set = do_posix_clock_nosettime,
3d44cc3e 295 .timer_create = no_timer_create,
70d715fd 296 .nsleep = no_nsleep,
2d42244a 297 };
da15cfda
JS
298 struct k_clock clock_realtime_coarse = {
299 .clock_getres = posix_get_coarse_res,
300 .clock_get = posix_get_realtime_coarse,
301 .clock_set = do_posix_clock_nosettime,
302 .timer_create = no_timer_create,
303 .nsleep = no_nsleep,
304 };
305 struct k_clock clock_monotonic_coarse = {
306 .clock_getres = posix_get_coarse_res,
307 .clock_get = posix_get_monotonic_coarse,
308 .clock_set = do_posix_clock_nosettime,
309 .timer_create = no_timer_create,
310 .nsleep = no_nsleep,
311 };
1da177e4
LT
312
313 register_posix_clock(CLOCK_REALTIME, &clock_realtime);
314 register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
2d42244a 315 register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
da15cfda
JS
316 register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
317 register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
1da177e4
LT
318
319 posix_timers_cache = kmem_cache_create("posix_timers_cache",
040b5c6f
AD
320 sizeof (struct k_itimer), 0, SLAB_PANIC,
321 NULL);
1da177e4
LT
322 idr_init(&posix_timers_id);
323 return 0;
324}
325
326__initcall(init_posix_timers);
327
1da177e4
LT
328static void schedule_next_timer(struct k_itimer *timr)
329{
44f21475
RZ
330 struct hrtimer *timer = &timr->it.real.timer;
331
becf8b5d 332 if (timr->it.real.interval.tv64 == 0)
1da177e4
LT
333 return;
334
4d672e7a
DL
335 timr->it_overrun += (unsigned int) hrtimer_forward(timer,
336 timer->base->get_time(),
337 timr->it.real.interval);
44f21475 338
1da177e4
LT
339 timr->it_overrun_last = timr->it_overrun;
340 timr->it_overrun = -1;
341 ++timr->it_requeue_pending;
44f21475 342 hrtimer_restart(timer);
1da177e4
LT
343}
344
345/*
346 * This function is exported for use by the signal deliver code. It is
347 * called just prior to the info block being released and passes that
348 * block to us. It's function is to update the overrun entry AND to
349 * restart the timer. It should only be called if the timer is to be
350 * restarted (i.e. we have flagged this in the sys_private entry of the
351 * info block).
352 *
353 * To protect aginst the timer going away while the interrupt is queued,
354 * we require that the it_requeue_pending flag be set.
355 */
356void do_schedule_next_timer(struct siginfo *info)
357{
358 struct k_itimer *timr;
359 unsigned long flags;
360
361 timr = lock_timer(info->si_tid, &flags);
362
becf8b5d
TG
363 if (timr && timr->it_requeue_pending == info->si_sys_private) {
364 if (timr->it_clock < 0)
365 posix_cpu_timer_schedule(timr);
366 else
367 schedule_next_timer(timr);
1da177e4 368
54da1174 369 info->si_overrun += timr->it_overrun_last;
becf8b5d
TG
370 }
371
b6557fbc
TG
372 if (timr)
373 unlock_timer(timr, flags);
1da177e4
LT
374}
375
ba661292 376int posix_timer_event(struct k_itimer *timr, int si_private)
1da177e4 377{
27af4245
ON
378 struct task_struct *task;
379 int shared, ret = -1;
ba661292
ON
380 /*
381 * FIXME: if ->sigq is queued we can race with
382 * dequeue_signal()->do_schedule_next_timer().
383 *
384 * If dequeue_signal() sees the "right" value of
385 * si_sys_private it calls do_schedule_next_timer().
386 * We re-queue ->sigq and drop ->it_lock().
387 * do_schedule_next_timer() locks the timer
388 * and re-schedules it while ->sigq is pending.
389 * Not really bad, but not that we want.
390 */
1da177e4 391 timr->sigq->info.si_sys_private = si_private;
1da177e4 392
27af4245
ON
393 rcu_read_lock();
394 task = pid_task(timr->it_pid, PIDTYPE_PID);
395 if (task) {
396 shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
397 ret = send_sigqueue(timr->sigq, task, shared);
398 }
399 rcu_read_unlock();
4aa73611
ON
400 /* If we failed to send the signal the timer stops. */
401 return ret > 0;
1da177e4
LT
402}
403EXPORT_SYMBOL_GPL(posix_timer_event);
404
405/*
406 * This function gets called when a POSIX.1b interval timer expires. It
407 * is used as a callback from the kernel internal timer. The
408 * run_timer_list code ALWAYS calls with interrupts on.
409
410 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
411 */
c9cb2e3d 412static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
1da177e4 413{
05cfb614 414 struct k_itimer *timr;
1da177e4 415 unsigned long flags;
becf8b5d 416 int si_private = 0;
c9cb2e3d 417 enum hrtimer_restart ret = HRTIMER_NORESTART;
1da177e4 418
05cfb614 419 timr = container_of(timer, struct k_itimer, it.real.timer);
1da177e4 420 spin_lock_irqsave(&timr->it_lock, flags);
1da177e4 421
becf8b5d
TG
422 if (timr->it.real.interval.tv64 != 0)
423 si_private = ++timr->it_requeue_pending;
1da177e4 424
becf8b5d
TG
425 if (posix_timer_event(timr, si_private)) {
426 /*
427 * signal was not sent because of sig_ignor
428 * we will not get a call back to restart it AND
429 * it should be restarted.
430 */
431 if (timr->it.real.interval.tv64 != 0) {
58229a18
TG
432 ktime_t now = hrtimer_cb_get_time(timer);
433
434 /*
435 * FIXME: What we really want, is to stop this
436 * timer completely and restart it in case the
437 * SIG_IGN is removed. This is a non trivial
438 * change which involves sighand locking
439 * (sigh !), which we don't want to do late in
440 * the release cycle.
441 *
442 * For now we just let timers with an interval
443 * less than a jiffie expire every jiffie to
444 * avoid softirq starvation in case of SIG_IGN
445 * and a very small interval, which would put
446 * the timer right back on the softirq pending
447 * list. By moving now ahead of time we trick
448 * hrtimer_forward() to expire the timer
449 * later, while we still maintain the overrun
450 * accuracy, but have some inconsistency in
451 * the timer_gettime() case. This is at least
452 * better than a starved softirq. A more
453 * complex fix which solves also another related
454 * inconsistency is already in the pipeline.
455 */
456#ifdef CONFIG_HIGH_RES_TIMERS
457 {
458 ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
459
460 if (timr->it.real.interval.tv64 < kj.tv64)
461 now = ktime_add(now, kj);
462 }
463#endif
4d672e7a 464 timr->it_overrun += (unsigned int)
58229a18 465 hrtimer_forward(timer, now,
becf8b5d
TG
466 timr->it.real.interval);
467 ret = HRTIMER_RESTART;
a0a0c28c 468 ++timr->it_requeue_pending;
1da177e4 469 }
1da177e4 470 }
1da177e4 471
becf8b5d
TG
472 unlock_timer(timr, flags);
473 return ret;
474}
1da177e4 475
27af4245 476static struct pid *good_sigevent(sigevent_t * event)
1da177e4
LT
477{
478 struct task_struct *rtn = current->group_leader;
479
480 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
8dc86af0 481 (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
bac0abd6 482 !same_thread_group(rtn, current) ||
1da177e4
LT
483 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
484 return NULL;
485
486 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
487 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
488 return NULL;
489
27af4245 490 return task_pid(rtn);
1da177e4
LT
491}
492
a924b04d 493void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
1da177e4
LT
494{
495 if ((unsigned) clock_id >= MAX_CLOCKS) {
496 printk("POSIX clock register failed for clock_id %d\n",
497 clock_id);
498 return;
499 }
500
501 posix_clocks[clock_id] = *new_clock;
502}
503EXPORT_SYMBOL_GPL(register_posix_clock);
504
505static struct k_itimer * alloc_posix_timer(void)
506{
507 struct k_itimer *tmr;
c3762229 508 tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
1da177e4
LT
509 if (!tmr)
510 return tmr;
1da177e4
LT
511 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
512 kmem_cache_free(posix_timers_cache, tmr);
aa94fbd5 513 return NULL;
1da177e4 514 }
ba661292 515 memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
1da177e4
LT
516 return tmr;
517}
518
519#define IT_ID_SET 1
520#define IT_ID_NOT_SET 0
521static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
522{
523 if (it_id_set) {
524 unsigned long flags;
525 spin_lock_irqsave(&idr_lock, flags);
526 idr_remove(&posix_timers_id, tmr->it_id);
527 spin_unlock_irqrestore(&idr_lock, flags);
528 }
89992102 529 put_pid(tmr->it_pid);
1da177e4 530 sigqueue_free(tmr->sigq);
1da177e4
LT
531 kmem_cache_free(posix_timers_cache, tmr);
532}
533
534/* Create a POSIX.1b interval timer. */
535
362e9c07
HC
536SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
537 struct sigevent __user *, timer_event_spec,
538 timer_t __user *, created_timer_id)
1da177e4 539{
2cd499e3 540 struct k_itimer *new_timer;
ef864c95 541 int error, new_timer_id;
1da177e4
LT
542 sigevent_t event;
543 int it_id_set = IT_ID_NOT_SET;
544
545 if (invalid_clockid(which_clock))
546 return -EINVAL;
547
548 new_timer = alloc_posix_timer();
549 if (unlikely(!new_timer))
550 return -EAGAIN;
551
552 spin_lock_init(&new_timer->it_lock);
553 retry:
554 if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) {
555 error = -EAGAIN;
556 goto out;
557 }
558 spin_lock_irq(&idr_lock);
5a51b713 559 error = idr_get_new(&posix_timers_id, new_timer, &new_timer_id);
1da177e4 560 spin_unlock_irq(&idr_lock);
ef864c95
ON
561 if (error) {
562 if (error == -EAGAIN)
563 goto retry;
1da177e4 564 /*
0b0a3e7b 565 * Weird looking, but we return EAGAIN if the IDR is
1da177e4
LT
566 * full (proper POSIX return value for this)
567 */
568 error = -EAGAIN;
569 goto out;
570 }
571
572 it_id_set = IT_ID_SET;
573 new_timer->it_id = (timer_t) new_timer_id;
574 new_timer->it_clock = which_clock;
575 new_timer->it_overrun = -1;
1da177e4 576
1da177e4
LT
577 if (timer_event_spec) {
578 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
579 error = -EFAULT;
580 goto out;
581 }
36b2f046 582 rcu_read_lock();
89992102 583 new_timer->it_pid = get_pid(good_sigevent(&event));
36b2f046 584 rcu_read_unlock();
89992102 585 if (!new_timer->it_pid) {
1da177e4
LT
586 error = -EINVAL;
587 goto out;
588 }
589 } else {
5a9fa730
ON
590 event.sigev_notify = SIGEV_SIGNAL;
591 event.sigev_signo = SIGALRM;
592 event.sigev_value.sival_int = new_timer->it_id;
89992102 593 new_timer->it_pid = get_pid(task_tgid(current));
1da177e4
LT
594 }
595
5a9fa730
ON
596 new_timer->it_sigev_notify = event.sigev_notify;
597 new_timer->sigq->info.si_signo = event.sigev_signo;
598 new_timer->sigq->info.si_value = event.sigev_value;
717835d9 599 new_timer->sigq->info.si_tid = new_timer->it_id;
5a9fa730 600 new_timer->sigq->info.si_code = SI_TIMER;
717835d9 601
2b08de00
AV
602 if (copy_to_user(created_timer_id,
603 &new_timer_id, sizeof (new_timer_id))) {
604 error = -EFAULT;
605 goto out;
606 }
607
45e0fffc
AV
608 error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
609 if (error)
610 goto out;
611
36b2f046 612 spin_lock_irq(&current->sighand->siglock);
27af4245 613 new_timer->it_signal = current->signal;
36b2f046
ON
614 list_add(&new_timer->list, &current->signal->posix_timers);
615 spin_unlock_irq(&current->sighand->siglock);
ef864c95
ON
616
617 return 0;
1da177e4
LT
618 /*
619 * In the case of the timer belonging to another task, after
620 * the task is unlocked, the timer is owned by the other task
621 * and may cease to exist at any time. Don't use or modify
622 * new_timer after the unlock call.
623 */
1da177e4 624out:
ef864c95 625 release_posix_timer(new_timer, it_id_set);
1da177e4
LT
626 return error;
627}
628
1da177e4
LT
629/*
630 * Locking issues: We need to protect the result of the id look up until
631 * we get the timer locked down so it is not deleted under us. The
632 * removal is done under the idr spinlock so we use that here to bridge
633 * the find to the timer lock. To avoid a dead lock, the timer id MUST
634 * be release with out holding the timer lock.
635 */
20f33a03 636static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
1da177e4
LT
637{
638 struct k_itimer *timr;
639 /*
640 * Watch out here. We do a irqsave on the idr_lock and pass the
641 * flags part over to the timer lock. Must not let interrupts in
642 * while we are moving the lock.
643 */
1da177e4 644 spin_lock_irqsave(&idr_lock, *flags);
31d92845 645 timr = idr_find(&posix_timers_id, (int)timer_id);
1da177e4
LT
646 if (timr) {
647 spin_lock(&timr->it_lock);
89992102 648 if (timr->it_signal == current->signal) {
179394af 649 spin_unlock(&idr_lock);
31d92845
ON
650 return timr;
651 }
652 spin_unlock(&timr->it_lock);
653 }
654 spin_unlock_irqrestore(&idr_lock, *flags);
1da177e4 655
31d92845 656 return NULL;
1da177e4
LT
657}
658
659/*
660 * Get the time remaining on a POSIX.1b interval timer. This function
661 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
662 * mess with irq.
663 *
664 * We have a couple of messes to clean up here. First there is the case
665 * of a timer that has a requeue pending. These timers should appear to
666 * be in the timer list with an expiry as if we were to requeue them
667 * now.
668 *
669 * The second issue is the SIGEV_NONE timer which may be active but is
670 * not really ever put in the timer list (to save system resources).
671 * This timer may be expired, and if so, we will do it here. Otherwise
672 * it is the same as a requeue pending timer WRT to what we should
673 * report.
674 */
675static void
676common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
677{
3b98a532 678 ktime_t now, remaining, iv;
becf8b5d 679 struct hrtimer *timer = &timr->it.real.timer;
1da177e4 680
becf8b5d 681 memset(cur_setting, 0, sizeof(struct itimerspec));
becf8b5d 682
3b98a532
RZ
683 iv = timr->it.real.interval;
684
becf8b5d 685 /* interval timer ? */
3b98a532
RZ
686 if (iv.tv64)
687 cur_setting->it_interval = ktime_to_timespec(iv);
688 else if (!hrtimer_active(timer) &&
689 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
becf8b5d 690 return;
3b98a532
RZ
691
692 now = timer->base->get_time();
693
becf8b5d 694 /*
3b98a532
RZ
695 * When a requeue is pending or this is a SIGEV_NONE
696 * timer move the expiry time forward by intervals, so
697 * expiry is > now.
becf8b5d 698 */
3b98a532
RZ
699 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
700 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
4d672e7a 701 timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
3b98a532 702
cc584b21 703 remaining = ktime_sub(hrtimer_get_expires(timer), now);
becf8b5d 704 /* Return 0 only, when the timer is expired and not pending */
3b98a532
RZ
705 if (remaining.tv64 <= 0) {
706 /*
707 * A single shot SIGEV_NONE timer must return 0, when
708 * it is expired !
709 */
710 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
711 cur_setting->it_value.tv_nsec = 1;
712 } else
becf8b5d 713 cur_setting->it_value = ktime_to_timespec(remaining);
1da177e4
LT
714}
715
716/* Get the time remaining on a POSIX.1b interval timer. */
362e9c07
HC
717SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
718 struct itimerspec __user *, setting)
1da177e4
LT
719{
720 struct k_itimer *timr;
721 struct itimerspec cur_setting;
722 unsigned long flags;
723
724 timr = lock_timer(timer_id, &flags);
725 if (!timr)
726 return -EINVAL;
727
728 CLOCK_DISPATCH(timr->it_clock, timer_get, (timr, &cur_setting));
729
730 unlock_timer(timr, flags);
731
732 if (copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
733 return -EFAULT;
734
735 return 0;
736}
becf8b5d 737
1da177e4
LT
738/*
739 * Get the number of overruns of a POSIX.1b interval timer. This is to
740 * be the overrun of the timer last delivered. At the same time we are
741 * accumulating overruns on the next timer. The overrun is frozen when
742 * the signal is delivered, either at the notify time (if the info block
743 * is not queued) or at the actual delivery time (as we are informed by
744 * the call back to do_schedule_next_timer(). So all we need to do is
745 * to pick up the frozen overrun.
746 */
362e9c07 747SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
1da177e4
LT
748{
749 struct k_itimer *timr;
750 int overrun;
5ba25331 751 unsigned long flags;
1da177e4
LT
752
753 timr = lock_timer(timer_id, &flags);
754 if (!timr)
755 return -EINVAL;
756
757 overrun = timr->it_overrun_last;
758 unlock_timer(timr, flags);
759
760 return overrun;
761}
1da177e4
LT
762
763/* Set a POSIX.1b interval timer. */
764/* timr->it_lock is taken. */
858119e1 765static int
1da177e4
LT
766common_timer_set(struct k_itimer *timr, int flags,
767 struct itimerspec *new_setting, struct itimerspec *old_setting)
768{
becf8b5d 769 struct hrtimer *timer = &timr->it.real.timer;
7978672c 770 enum hrtimer_mode mode;
1da177e4
LT
771
772 if (old_setting)
773 common_timer_get(timr, old_setting);
774
775 /* disable the timer */
becf8b5d 776 timr->it.real.interval.tv64 = 0;
1da177e4
LT
777 /*
778 * careful here. If smp we could be in the "fire" routine which will
779 * be spinning as we hold the lock. But this is ONLY an SMP issue.
780 */
becf8b5d 781 if (hrtimer_try_to_cancel(timer) < 0)
1da177e4 782 return TIMER_RETRY;
1da177e4
LT
783
784 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
785 ~REQUEUE_PENDING;
786 timr->it_overrun_last = 0;
1da177e4 787
becf8b5d
TG
788 /* switch off the timer when it_value is zero */
789 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
790 return 0;
1da177e4 791
c9cb2e3d 792 mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
7978672c 793 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
7978672c 794 timr->it.real.timer.function = posix_timer_fn;
becf8b5d 795
cc584b21 796 hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
becf8b5d
TG
797
798 /* Convert interval */
799 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
800
801 /* SIGEV_NONE timers are not queued ! See common_timer_get */
952bbc87
TG
802 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
803 /* Setup correct expiry time for relative timers */
5a7780e7 804 if (mode == HRTIMER_MODE_REL) {
cc584b21 805 hrtimer_add_expires(timer, timer->base->get_time());
5a7780e7 806 }
becf8b5d 807 return 0;
952bbc87 808 }
becf8b5d 809
cc584b21 810 hrtimer_start_expires(timer, mode);
1da177e4
LT
811 return 0;
812}
813
814/* Set a POSIX.1b interval timer */
362e9c07
HC
815SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
816 const struct itimerspec __user *, new_setting,
817 struct itimerspec __user *, old_setting)
1da177e4
LT
818{
819 struct k_itimer *timr;
820 struct itimerspec new_spec, old_spec;
821 int error = 0;
5ba25331 822 unsigned long flag;
1da177e4
LT
823 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
824
825 if (!new_setting)
826 return -EINVAL;
827
828 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
829 return -EFAULT;
830
becf8b5d
TG
831 if (!timespec_valid(&new_spec.it_interval) ||
832 !timespec_valid(&new_spec.it_value))
1da177e4
LT
833 return -EINVAL;
834retry:
835 timr = lock_timer(timer_id, &flag);
836 if (!timr)
837 return -EINVAL;
838
839 error = CLOCK_DISPATCH(timr->it_clock, timer_set,
840 (timr, flags, &new_spec, rtn));
841
842 unlock_timer(timr, flag);
843 if (error == TIMER_RETRY) {
844 rtn = NULL; // We already got the old time...
845 goto retry;
846 }
847
becf8b5d
TG
848 if (old_setting && !error &&
849 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
1da177e4
LT
850 error = -EFAULT;
851
852 return error;
853}
854
855static inline int common_timer_del(struct k_itimer *timer)
856{
becf8b5d 857 timer->it.real.interval.tv64 = 0;
f972be33 858
becf8b5d 859 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
1da177e4 860 return TIMER_RETRY;
1da177e4
LT
861 return 0;
862}
863
864static inline int timer_delete_hook(struct k_itimer *timer)
865{
866 return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer));
867}
868
869/* Delete a POSIX.1b interval timer. */
362e9c07 870SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
1da177e4
LT
871{
872 struct k_itimer *timer;
5ba25331 873 unsigned long flags;
1da177e4 874
1da177e4 875retry_delete:
1da177e4
LT
876 timer = lock_timer(timer_id, &flags);
877 if (!timer)
878 return -EINVAL;
879
becf8b5d 880 if (timer_delete_hook(timer) == TIMER_RETRY) {
1da177e4
LT
881 unlock_timer(timer, flags);
882 goto retry_delete;
883 }
becf8b5d 884
1da177e4
LT
885 spin_lock(&current->sighand->siglock);
886 list_del(&timer->list);
887 spin_unlock(&current->sighand->siglock);
888 /*
889 * This keeps any tasks waiting on the spin lock from thinking
890 * they got something (see the lock code above).
891 */
89992102 892 timer->it_signal = NULL;
4b7a1304 893
1da177e4
LT
894 unlock_timer(timer, flags);
895 release_posix_timer(timer, IT_ID_SET);
896 return 0;
897}
becf8b5d 898
1da177e4
LT
899/*
900 * return timer owned by the process, used by exit_itimers
901 */
858119e1 902static void itimer_delete(struct k_itimer *timer)
1da177e4
LT
903{
904 unsigned long flags;
905
1da177e4 906retry_delete:
1da177e4
LT
907 spin_lock_irqsave(&timer->it_lock, flags);
908
becf8b5d 909 if (timer_delete_hook(timer) == TIMER_RETRY) {
1da177e4
LT
910 unlock_timer(timer, flags);
911 goto retry_delete;
912 }
1da177e4
LT
913 list_del(&timer->list);
914 /*
915 * This keeps any tasks waiting on the spin lock from thinking
916 * they got something (see the lock code above).
917 */
89992102 918 timer->it_signal = NULL;
4b7a1304 919
1da177e4
LT
920 unlock_timer(timer, flags);
921 release_posix_timer(timer, IT_ID_SET);
922}
923
924/*
25f407f0 925 * This is called by do_exit or de_thread, only when there are no more
1da177e4
LT
926 * references to the shared signal_struct.
927 */
928void exit_itimers(struct signal_struct *sig)
929{
930 struct k_itimer *tmr;
931
932 while (!list_empty(&sig->posix_timers)) {
933 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
934 itimer_delete(tmr);
935 }
936}
937
becf8b5d 938/* Not available / possible... functions */
1e6d7679 939int do_posix_clock_nosettime(const clockid_t clockid, const struct timespec *tp)
1da177e4
LT
940{
941 return -EINVAL;
942}
943EXPORT_SYMBOL_GPL(do_posix_clock_nosettime);
944
a924b04d 945int do_posix_clock_nonanosleep(const clockid_t clock, int flags,
97735f25 946 struct timespec *t, struct timespec __user *r)
1da177e4 947{
65da528d 948 return -ENANOSLEEP_NOTSUP;
1da177e4
LT
949}
950EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep);
951
362e9c07
HC
952SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
953 const struct timespec __user *, tp)
1da177e4
LT
954{
955 struct timespec new_tp;
956
957 if (invalid_clockid(which_clock))
958 return -EINVAL;
959 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
960 return -EFAULT;
961
962 return CLOCK_DISPATCH(which_clock, clock_set, (which_clock, &new_tp));
963}
964
362e9c07
HC
965SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
966 struct timespec __user *,tp)
1da177e4
LT
967{
968 struct timespec kernel_tp;
969 int error;
970
971 if (invalid_clockid(which_clock))
972 return -EINVAL;
973 error = CLOCK_DISPATCH(which_clock, clock_get,
974 (which_clock, &kernel_tp));
975 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
976 error = -EFAULT;
977
978 return error;
979
980}
981
362e9c07
HC
982SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
983 struct timespec __user *, tp)
1da177e4
LT
984{
985 struct timespec rtn_tp;
986 int error;
987
988 if (invalid_clockid(which_clock))
989 return -EINVAL;
990
991 error = CLOCK_DISPATCH(which_clock, clock_getres,
992 (which_clock, &rtn_tp));
993
994 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) {
995 error = -EFAULT;
996 }
997
998 return error;
999}
1000
97735f25
TG
1001/*
1002 * nanosleep for monotonic and realtime clocks
1003 */
1004static int common_nsleep(const clockid_t which_clock, int flags,
1005 struct timespec *tsave, struct timespec __user *rmtp)
1006{
080344b9
ON
1007 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
1008 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
1009 which_clock);
97735f25 1010}
1da177e4 1011
362e9c07
HC
1012SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
1013 const struct timespec __user *, rqtp,
1014 struct timespec __user *, rmtp)
1da177e4
LT
1015{
1016 struct timespec t;
1da177e4
LT
1017
1018 if (invalid_clockid(which_clock))
1019 return -EINVAL;
1020
1021 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
1022 return -EFAULT;
1023
5f82b2b7 1024 if (!timespec_valid(&t))
1da177e4
LT
1025 return -EINVAL;
1026
97735f25
TG
1027 return CLOCK_DISPATCH(which_clock, nsleep,
1028 (which_clock, flags, &t, rmtp));
1da177e4 1029}
1711ef38
TA
1030
1031/*
1032 * nanosleep_restart for monotonic and realtime clocks
1033 */
1034static int common_nsleep_restart(struct restart_block *restart_block)
1035{
1036 return hrtimer_nanosleep_restart(restart_block);
1037}
1038
1039/*
1040 * This will restart clock_nanosleep. This is required only by
1041 * compat_clock_nanosleep_restart for now.
1042 */
1043long
1044clock_nanosleep_restart(struct restart_block *restart_block)
1045{
1046 clockid_t which_clock = restart_block->arg0;
1047
1048 return CLOCK_DISPATCH(which_clock, nsleep_restart,
1049 (restart_block));
1050}