ia64/linux-2.6.18-xen.hg

view kernel/posix-timers.c @ 562:66faefe721eb

pvSCSI backend driver

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Jun 02 09:58:27 2008 +0100 (2008-06-02)
parents 831230e53067
children
line source
1 /*
2 * linux/kernel/posix_timers.c
3 *
4 *
5 * 2002-10-15 Posix Clocks & timers
6 * by George Anzinger george@mvista.com
7 *
8 * Copyright (C) 2002 2003 by MontaVista Software.
9 *
10 * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
11 * Copyright (C) 2004 Boris Hu
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or (at
16 * your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful, but
19 * WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 * General Public License for more details.
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 */
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 #include <linux/mutex.h>
40 #include <asm/uaccess.h>
41 #include <asm/semaphore.h>
42 #include <linux/list.h>
43 #include <linux/init.h>
44 #include <linux/compiler.h>
45 #include <linux/idr.h>
46 #include <linux/posix-timers.h>
47 #include <linux/syscalls.h>
48 #include <linux/wait.h>
49 #include <linux/workqueue.h>
50 #include <linux/module.h>
52 /*
53 * Management arrays for POSIX timers. Timers are kept in slab memory
54 * Timer ids are allocated by an external routine that keeps track of the
55 * id and the timer. The external interface is:
56 *
57 * void *idr_find(struct idr *idp, int id); to find timer_id <id>
58 * int idr_get_new(struct idr *idp, void *ptr); to get a new id and
59 * related it to <ptr>
60 * void idr_remove(struct idr *idp, int id); to release <id>
61 * void idr_init(struct idr *idp); to initialize <idp>
62 * which we supply.
63 * The idr_get_new *may* call slab for more memory so it must not be
64 * called under a spin lock. Likewise idr_remore may release memory
65 * (but it may be ok to do this under a lock...).
66 * idr_find is just a memory look up and is quite fast. A -1 return
67 * indicates that the requested id does not exist.
68 */
70 /*
71 * Lets keep our timers in a slab cache :-)
72 */
73 static kmem_cache_t *posix_timers_cache;
74 static struct idr posix_timers_id;
75 static DEFINE_SPINLOCK(idr_lock);
77 /*
78 * we assume that the new SIGEV_THREAD_ID shares no bits with the other
79 * SIGEV values. Here we put out an error if this assumption fails.
80 */
81 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
82 ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
83 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
84 #endif
87 /*
88 * The timer ID is turned into a timer address by idr_find().
89 * Verifying a valid ID consists of:
90 *
91 * a) checking that idr_find() returns other than -1.
92 * b) checking that the timer id matches the one in the timer itself.
93 * c) that the timer owner is in the callers thread group.
94 */
96 /*
97 * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
98 * to implement others. This structure defines the various
99 * clocks and allows the possibility of adding others. We
100 * provide an interface to add clocks to the table and expect
101 * the "arch" code to add at least one clock that is high
102 * resolution. Here we define the standard CLOCK_REALTIME as a
103 * 1/HZ resolution clock.
104 *
105 * RESOLUTION: Clock resolution is used to round up timer and interval
106 * times, NOT to report clock times, which are reported with as
107 * much resolution as the system can muster. In some cases this
108 * resolution may depend on the underlying clock hardware and
109 * may not be quantifiable until run time, and only then is the
110 * necessary code is written. The standard says we should say
111 * something about this issue in the documentation...
112 *
113 * FUNCTIONS: The CLOCKs structure defines possible functions to handle
114 * various clock functions. For clocks that use the standard
115 * system timer code these entries should be NULL. This will
116 * allow dispatch without the overhead of indirect function
117 * calls. CLOCKS that depend on other sources (e.g. WWV or GPS)
118 * must supply functions here, even if the function just returns
119 * ENOSYS. The standard POSIX timer management code assumes the
120 * following: 1.) The k_itimer struct (sched.h) is used for the
121 * timer. 2.) The list, it_lock, it_clock, it_id and it_process
122 * fields are not modified by timer code.
123 *
124 * At this time all functions EXCEPT clock_nanosleep can be
125 * redirected by the CLOCKS structure. Clock_nanosleep is in
126 * there, but the code ignores it.
127 *
128 * Permissions: It is assumed that the clock_settime() function defined
129 * for each clock will take care of permission checks. Some
130 * clocks may be set able by any user (i.e. local process
131 * clocks) others not. Currently the only set able clock we
132 * have is CLOCK_REALTIME and its high res counter part, both of
133 * which we beg off on and pass to do_sys_settimeofday().
134 */
136 static struct k_clock posix_clocks[MAX_CLOCKS];
138 /*
139 * These ones are defined below.
140 */
141 static int common_nsleep(const clockid_t, int flags, struct timespec *t,
142 struct timespec __user *rmtp);
143 static void common_timer_get(struct k_itimer *, struct itimerspec *);
144 static int common_timer_set(struct k_itimer *, int,
145 struct itimerspec *, struct itimerspec *);
146 static int common_timer_del(struct k_itimer *timer);
148 static int posix_timer_fn(struct hrtimer *data);
150 static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags);
152 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
153 {
154 spin_unlock_irqrestore(&timr->it_lock, flags);
155 }
157 /*
158 * Call the k_clock hook function if non-null, or the default function.
159 */
160 #define CLOCK_DISPATCH(clock, call, arglist) \
161 ((clock) < 0 ? posix_cpu_##call arglist : \
162 (posix_clocks[clock].call != NULL \
163 ? (*posix_clocks[clock].call) arglist : common_##call arglist))
165 /*
166 * Default clock hook functions when the struct k_clock passed
167 * to register_posix_clock leaves a function pointer null.
168 *
169 * The function common_CALL is the default implementation for
170 * the function pointer CALL in struct k_clock.
171 */
173 static inline int common_clock_getres(const clockid_t which_clock,
174 struct timespec *tp)
175 {
176 tp->tv_sec = 0;
177 tp->tv_nsec = posix_clocks[which_clock].res;
178 return 0;
179 }
181 /*
182 * Get real time for posix timers
183 */
184 static int common_clock_get(clockid_t which_clock, struct timespec *tp)
185 {
186 ktime_get_real_ts(tp);
187 return 0;
188 }
190 static inline int common_clock_set(const clockid_t which_clock,
191 struct timespec *tp)
192 {
193 return do_sys_settimeofday(tp, NULL);
194 }
196 static int common_timer_create(struct k_itimer *new_timer)
197 {
198 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
199 return 0;
200 }
202 /*
203 * Return nonzero if we know a priori this clockid_t value is bogus.
204 */
205 static inline int invalid_clockid(const clockid_t which_clock)
206 {
207 if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */
208 return 0;
209 if ((unsigned) which_clock >= MAX_CLOCKS)
210 return 1;
211 if (posix_clocks[which_clock].clock_getres != NULL)
212 return 0;
213 if (posix_clocks[which_clock].res != 0)
214 return 0;
215 return 1;
216 }
218 /*
219 * Get monotonic time for posix timers
220 */
221 static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
222 {
223 ktime_get_ts(tp);
224 return 0;
225 }
227 /*
228 * Initialize everything, well, just everything in Posix clocks/timers ;)
229 */
230 static __init int init_posix_timers(void)
231 {
232 struct k_clock clock_realtime = {
233 .clock_getres = hrtimer_get_res,
234 };
235 struct k_clock clock_monotonic = {
236 .clock_getres = hrtimer_get_res,
237 .clock_get = posix_ktime_get_ts,
238 .clock_set = do_posix_clock_nosettime,
239 };
241 register_posix_clock(CLOCK_REALTIME, &clock_realtime);
242 register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
244 posix_timers_cache = kmem_cache_create("posix_timers_cache",
245 sizeof (struct k_itimer), 0, 0, NULL, NULL);
246 idr_init(&posix_timers_id);
247 return 0;
248 }
250 __initcall(init_posix_timers);
252 static void schedule_next_timer(struct k_itimer *timr)
253 {
254 struct hrtimer *timer = &timr->it.real.timer;
256 if (timr->it.real.interval.tv64 == 0)
257 return;
259 timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
260 timr->it.real.interval);
262 timr->it_overrun_last = timr->it_overrun;
263 timr->it_overrun = -1;
264 ++timr->it_requeue_pending;
265 hrtimer_restart(timer);
266 }
268 /*
269 * This function is exported for use by the signal deliver code. It is
270 * called just prior to the info block being released and passes that
271 * block to us. It's function is to update the overrun entry AND to
272 * restart the timer. It should only be called if the timer is to be
273 * restarted (i.e. we have flagged this in the sys_private entry of the
274 * info block).
275 *
276 * To protect aginst the timer going away while the interrupt is queued,
277 * we require that the it_requeue_pending flag be set.
278 */
279 void do_schedule_next_timer(struct siginfo *info)
280 {
281 struct k_itimer *timr;
282 unsigned long flags;
284 timr = lock_timer(info->si_tid, &flags);
286 if (timr && timr->it_requeue_pending == info->si_sys_private) {
287 if (timr->it_clock < 0)
288 posix_cpu_timer_schedule(timr);
289 else
290 schedule_next_timer(timr);
292 info->si_overrun = timr->it_overrun_last;
293 }
295 if (timr)
296 unlock_timer(timr, flags);
297 }
299 int posix_timer_event(struct k_itimer *timr,int si_private)
300 {
301 memset(&timr->sigq->info, 0, sizeof(siginfo_t));
302 timr->sigq->info.si_sys_private = si_private;
303 /* Send signal to the process that owns this timer.*/
305 timr->sigq->info.si_signo = timr->it_sigev_signo;
306 timr->sigq->info.si_errno = 0;
307 timr->sigq->info.si_code = SI_TIMER;
308 timr->sigq->info.si_tid = timr->it_id;
309 timr->sigq->info.si_value = timr->it_sigev_value;
311 if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
312 struct task_struct *leader;
313 int ret = send_sigqueue(timr->it_sigev_signo, timr->sigq,
314 timr->it_process);
316 if (likely(ret >= 0))
317 return ret;
319 timr->it_sigev_notify = SIGEV_SIGNAL;
320 leader = timr->it_process->group_leader;
321 put_task_struct(timr->it_process);
322 timr->it_process = leader;
323 }
325 return send_group_sigqueue(timr->it_sigev_signo, timr->sigq,
326 timr->it_process);
327 }
328 EXPORT_SYMBOL_GPL(posix_timer_event);
330 /*
331 * This function gets called when a POSIX.1b interval timer expires. It
332 * is used as a callback from the kernel internal timer. The
333 * run_timer_list code ALWAYS calls with interrupts on.
335 * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
336 */
337 static int posix_timer_fn(struct hrtimer *timer)
338 {
339 struct k_itimer *timr;
340 unsigned long flags;
341 int si_private = 0;
342 int ret = HRTIMER_NORESTART;
344 timr = container_of(timer, struct k_itimer, it.real.timer);
345 spin_lock_irqsave(&timr->it_lock, flags);
347 if (timr->it.real.interval.tv64 != 0)
348 si_private = ++timr->it_requeue_pending;
350 if (posix_timer_event(timr, si_private)) {
351 /*
352 * signal was not sent because of sig_ignor
353 * we will not get a call back to restart it AND
354 * it should be restarted.
355 */
356 if (timr->it.real.interval.tv64 != 0) {
357 timr->it_overrun +=
358 hrtimer_forward(timer,
359 timer->base->softirq_time,
360 timr->it.real.interval);
361 ret = HRTIMER_RESTART;
362 ++timr->it_requeue_pending;
363 }
364 }
366 unlock_timer(timr, flags);
367 return ret;
368 }
370 static struct task_struct * good_sigevent(sigevent_t * event)
371 {
372 struct task_struct *rtn = current->group_leader;
374 if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
375 (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) ||
376 rtn->tgid != current->tgid ||
377 (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
378 return NULL;
380 if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
381 ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
382 return NULL;
384 return rtn;
385 }
387 void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
388 {
389 if ((unsigned) clock_id >= MAX_CLOCKS) {
390 printk("POSIX clock register failed for clock_id %d\n",
391 clock_id);
392 return;
393 }
395 posix_clocks[clock_id] = *new_clock;
396 }
397 EXPORT_SYMBOL_GPL(register_posix_clock);
399 static struct k_itimer * alloc_posix_timer(void)
400 {
401 struct k_itimer *tmr;
402 tmr = kmem_cache_alloc(posix_timers_cache, GFP_KERNEL);
403 if (!tmr)
404 return tmr;
405 memset(tmr, 0, sizeof (struct k_itimer));
406 if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
407 kmem_cache_free(posix_timers_cache, tmr);
408 tmr = NULL;
409 }
410 return tmr;
411 }
413 #define IT_ID_SET 1
414 #define IT_ID_NOT_SET 0
415 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
416 {
417 if (it_id_set) {
418 unsigned long flags;
419 spin_lock_irqsave(&idr_lock, flags);
420 idr_remove(&posix_timers_id, tmr->it_id);
421 spin_unlock_irqrestore(&idr_lock, flags);
422 }
423 sigqueue_free(tmr->sigq);
424 if (unlikely(tmr->it_process) &&
425 tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
426 put_task_struct(tmr->it_process);
427 kmem_cache_free(posix_timers_cache, tmr);
428 }
430 /* Create a POSIX.1b interval timer. */
432 asmlinkage long
433 sys_timer_create(const clockid_t which_clock,
434 struct sigevent __user *timer_event_spec,
435 timer_t __user * created_timer_id)
436 {
437 int error = 0;
438 struct k_itimer *new_timer = NULL;
439 int new_timer_id;
440 struct task_struct *process = NULL;
441 unsigned long flags;
442 sigevent_t event;
443 int it_id_set = IT_ID_NOT_SET;
445 if (invalid_clockid(which_clock))
446 return -EINVAL;
448 new_timer = alloc_posix_timer();
449 if (unlikely(!new_timer))
450 return -EAGAIN;
452 spin_lock_init(&new_timer->it_lock);
453 retry:
454 if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) {
455 error = -EAGAIN;
456 goto out;
457 }
458 spin_lock_irq(&idr_lock);
459 error = idr_get_new(&posix_timers_id, (void *) new_timer,
460 &new_timer_id);
461 spin_unlock_irq(&idr_lock);
462 if (error == -EAGAIN)
463 goto retry;
464 else if (error) {
465 /*
466 * Wierd looking, but we return EAGAIN if the IDR is
467 * full (proper POSIX return value for this)
468 */
469 error = -EAGAIN;
470 goto out;
471 }
473 it_id_set = IT_ID_SET;
474 new_timer->it_id = (timer_t) new_timer_id;
475 new_timer->it_clock = which_clock;
476 new_timer->it_overrun = -1;
477 error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
478 if (error)
479 goto out;
481 /*
482 * return the timer_id now. The next step is hard to
483 * back out if there is an error.
484 */
485 if (copy_to_user(created_timer_id,
486 &new_timer_id, sizeof (new_timer_id))) {
487 error = -EFAULT;
488 goto out;
489 }
490 if (timer_event_spec) {
491 if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
492 error = -EFAULT;
493 goto out;
494 }
495 new_timer->it_sigev_notify = event.sigev_notify;
496 new_timer->it_sigev_signo = event.sigev_signo;
497 new_timer->it_sigev_value = event.sigev_value;
499 read_lock(&tasklist_lock);
500 if ((process = good_sigevent(&event))) {
501 /*
502 * We may be setting up this process for another
503 * thread. It may be exiting. To catch this
504 * case the we check the PF_EXITING flag. If
505 * the flag is not set, the siglock will catch
506 * him before it is too late (in exit_itimers).
507 *
508 * The exec case is a bit more invloved but easy
509 * to code. If the process is in our thread
510 * group (and it must be or we would not allow
511 * it here) and is doing an exec, it will cause
512 * us to be killed. In this case it will wait
513 * for us to die which means we can finish this
514 * linkage with our last gasp. I.e. no code :)
515 */
516 spin_lock_irqsave(&process->sighand->siglock, flags);
517 if (!(process->flags & PF_EXITING)) {
518 new_timer->it_process = process;
519 list_add(&new_timer->list,
520 &process->signal->posix_timers);
521 spin_unlock_irqrestore(&process->sighand->siglock, flags);
522 if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
523 get_task_struct(process);
524 } else {
525 spin_unlock_irqrestore(&process->sighand->siglock, flags);
526 process = NULL;
527 }
528 }
529 read_unlock(&tasklist_lock);
530 if (!process) {
531 error = -EINVAL;
532 goto out;
533 }
534 } else {
535 new_timer->it_sigev_notify = SIGEV_SIGNAL;
536 new_timer->it_sigev_signo = SIGALRM;
537 new_timer->it_sigev_value.sival_int = new_timer->it_id;
538 process = current->group_leader;
539 spin_lock_irqsave(&process->sighand->siglock, flags);
540 new_timer->it_process = process;
541 list_add(&new_timer->list, &process->signal->posix_timers);
542 spin_unlock_irqrestore(&process->sighand->siglock, flags);
543 }
545 /*
546 * In the case of the timer belonging to another task, after
547 * the task is unlocked, the timer is owned by the other task
548 * and may cease to exist at any time. Don't use or modify
549 * new_timer after the unlock call.
550 */
552 out:
553 if (error)
554 release_posix_timer(new_timer, it_id_set);
556 return error;
557 }
559 /*
560 * Locking issues: We need to protect the result of the id look up until
561 * we get the timer locked down so it is not deleted under us. The
562 * removal is done under the idr spinlock so we use that here to bridge
563 * the find to the timer lock. To avoid a dead lock, the timer id MUST
564 * be release with out holding the timer lock.
565 */
566 static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags)
567 {
568 struct k_itimer *timr;
569 /*
570 * Watch out here. We do a irqsave on the idr_lock and pass the
571 * flags part over to the timer lock. Must not let interrupts in
572 * while we are moving the lock.
573 */
575 spin_lock_irqsave(&idr_lock, *flags);
576 timr = (struct k_itimer *) idr_find(&posix_timers_id, (int) timer_id);
577 if (timr) {
578 spin_lock(&timr->it_lock);
579 spin_unlock(&idr_lock);
581 if ((timr->it_id != timer_id) || !(timr->it_process) ||
582 timr->it_process->tgid != current->tgid) {
583 unlock_timer(timr, *flags);
584 timr = NULL;
585 }
586 } else
587 spin_unlock_irqrestore(&idr_lock, *flags);
589 return timr;
590 }
592 /*
593 * Get the time remaining on a POSIX.1b interval timer. This function
594 * is ALWAYS called with spin_lock_irq on the timer, thus it must not
595 * mess with irq.
596 *
597 * We have a couple of messes to clean up here. First there is the case
598 * of a timer that has a requeue pending. These timers should appear to
599 * be in the timer list with an expiry as if we were to requeue them
600 * now.
601 *
602 * The second issue is the SIGEV_NONE timer which may be active but is
603 * not really ever put in the timer list (to save system resources).
604 * This timer may be expired, and if so, we will do it here. Otherwise
605 * it is the same as a requeue pending timer WRT to what we should
606 * report.
607 */
608 static void
609 common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
610 {
611 ktime_t now, remaining, iv;
612 struct hrtimer *timer = &timr->it.real.timer;
614 memset(cur_setting, 0, sizeof(struct itimerspec));
616 iv = timr->it.real.interval;
618 /* interval timer ? */
619 if (iv.tv64)
620 cur_setting->it_interval = ktime_to_timespec(iv);
621 else if (!hrtimer_active(timer) &&
622 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
623 return;
625 now = timer->base->get_time();
627 /*
628 * When a requeue is pending or this is a SIGEV_NONE
629 * timer move the expiry time forward by intervals, so
630 * expiry is > now.
631 */
632 if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
633 (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
634 timr->it_overrun += hrtimer_forward(timer, now, iv);
636 remaining = ktime_sub(timer->expires, now);
637 /* Return 0 only, when the timer is expired and not pending */
638 if (remaining.tv64 <= 0) {
639 /*
640 * A single shot SIGEV_NONE timer must return 0, when
641 * it is expired !
642 */
643 if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
644 cur_setting->it_value.tv_nsec = 1;
645 } else
646 cur_setting->it_value = ktime_to_timespec(remaining);
647 }
649 /* Get the time remaining on a POSIX.1b interval timer. */
650 asmlinkage long
651 sys_timer_gettime(timer_t timer_id, struct itimerspec __user *setting)
652 {
653 struct k_itimer *timr;
654 struct itimerspec cur_setting;
655 unsigned long flags;
657 timr = lock_timer(timer_id, &flags);
658 if (!timr)
659 return -EINVAL;
661 CLOCK_DISPATCH(timr->it_clock, timer_get, (timr, &cur_setting));
663 unlock_timer(timr, flags);
665 if (copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
666 return -EFAULT;
668 return 0;
669 }
671 /*
672 * Get the number of overruns of a POSIX.1b interval timer. This is to
673 * be the overrun of the timer last delivered. At the same time we are
674 * accumulating overruns on the next timer. The overrun is frozen when
675 * the signal is delivered, either at the notify time (if the info block
676 * is not queued) or at the actual delivery time (as we are informed by
677 * the call back to do_schedule_next_timer(). So all we need to do is
678 * to pick up the frozen overrun.
679 */
680 asmlinkage long
681 sys_timer_getoverrun(timer_t timer_id)
682 {
683 struct k_itimer *timr;
684 int overrun;
685 long flags;
687 timr = lock_timer(timer_id, &flags);
688 if (!timr)
689 return -EINVAL;
691 overrun = timr->it_overrun_last;
692 unlock_timer(timr, flags);
694 return overrun;
695 }
697 /* Set a POSIX.1b interval timer. */
698 /* timr->it_lock is taken. */
699 static int
700 common_timer_set(struct k_itimer *timr, int flags,
701 struct itimerspec *new_setting, struct itimerspec *old_setting)
702 {
703 struct hrtimer *timer = &timr->it.real.timer;
704 enum hrtimer_mode mode;
706 if (old_setting)
707 common_timer_get(timr, old_setting);
709 /* disable the timer */
710 timr->it.real.interval.tv64 = 0;
711 /*
712 * careful here. If smp we could be in the "fire" routine which will
713 * be spinning as we hold the lock. But this is ONLY an SMP issue.
714 */
715 if (hrtimer_try_to_cancel(timer) < 0)
716 return TIMER_RETRY;
718 timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
719 ~REQUEUE_PENDING;
720 timr->it_overrun_last = 0;
722 /* switch off the timer when it_value is zero */
723 if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
724 return 0;
726 mode = flags & TIMER_ABSTIME ? HRTIMER_ABS : HRTIMER_REL;
727 hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
728 timr->it.real.timer.function = posix_timer_fn;
730 timer->expires = timespec_to_ktime(new_setting->it_value);
732 /* Convert interval */
733 timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
735 /* SIGEV_NONE timers are not queued ! See common_timer_get */
736 if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
737 /* Setup correct expiry time for relative timers */
738 if (mode == HRTIMER_REL)
739 timer->expires = ktime_add(timer->expires,
740 timer->base->get_time());
741 return 0;
742 }
744 hrtimer_start(timer, timer->expires, mode);
745 return 0;
746 }
748 /* Set a POSIX.1b interval timer */
749 asmlinkage long
750 sys_timer_settime(timer_t timer_id, int flags,
751 const struct itimerspec __user *new_setting,
752 struct itimerspec __user *old_setting)
753 {
754 struct k_itimer *timr;
755 struct itimerspec new_spec, old_spec;
756 int error = 0;
757 long flag;
758 struct itimerspec *rtn = old_setting ? &old_spec : NULL;
760 if (!new_setting)
761 return -EINVAL;
763 if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
764 return -EFAULT;
766 if (!timespec_valid(&new_spec.it_interval) ||
767 !timespec_valid(&new_spec.it_value))
768 return -EINVAL;
769 retry:
770 timr = lock_timer(timer_id, &flag);
771 if (!timr)
772 return -EINVAL;
774 error = CLOCK_DISPATCH(timr->it_clock, timer_set,
775 (timr, flags, &new_spec, rtn));
777 unlock_timer(timr, flag);
778 if (error == TIMER_RETRY) {
779 rtn = NULL; // We already got the old time...
780 goto retry;
781 }
783 if (old_setting && !error &&
784 copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
785 error = -EFAULT;
787 return error;
788 }
790 static inline int common_timer_del(struct k_itimer *timer)
791 {
792 timer->it.real.interval.tv64 = 0;
794 if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
795 return TIMER_RETRY;
796 return 0;
797 }
799 static inline int timer_delete_hook(struct k_itimer *timer)
800 {
801 return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer));
802 }
804 /* Delete a POSIX.1b interval timer. */
805 asmlinkage long
806 sys_timer_delete(timer_t timer_id)
807 {
808 struct k_itimer *timer;
809 long flags;
811 retry_delete:
812 timer = lock_timer(timer_id, &flags);
813 if (!timer)
814 return -EINVAL;
816 if (timer_delete_hook(timer) == TIMER_RETRY) {
817 unlock_timer(timer, flags);
818 goto retry_delete;
819 }
821 spin_lock(&current->sighand->siglock);
822 list_del(&timer->list);
823 spin_unlock(&current->sighand->siglock);
824 /*
825 * This keeps any tasks waiting on the spin lock from thinking
826 * they got something (see the lock code above).
827 */
828 if (timer->it_process) {
829 if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
830 put_task_struct(timer->it_process);
831 timer->it_process = NULL;
832 }
833 unlock_timer(timer, flags);
834 release_posix_timer(timer, IT_ID_SET);
835 return 0;
836 }
838 /*
839 * return timer owned by the process, used by exit_itimers
840 */
841 static void itimer_delete(struct k_itimer *timer)
842 {
843 unsigned long flags;
845 retry_delete:
846 spin_lock_irqsave(&timer->it_lock, flags);
848 if (timer_delete_hook(timer) == TIMER_RETRY) {
849 unlock_timer(timer, flags);
850 goto retry_delete;
851 }
852 list_del(&timer->list);
853 /*
854 * This keeps any tasks waiting on the spin lock from thinking
855 * they got something (see the lock code above).
856 */
857 if (timer->it_process) {
858 if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
859 put_task_struct(timer->it_process);
860 timer->it_process = NULL;
861 }
862 unlock_timer(timer, flags);
863 release_posix_timer(timer, IT_ID_SET);
864 }
866 /*
867 * This is called by do_exit or de_thread, only when there are no more
868 * references to the shared signal_struct.
869 */
870 void exit_itimers(struct signal_struct *sig)
871 {
872 struct k_itimer *tmr;
874 while (!list_empty(&sig->posix_timers)) {
875 tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
876 itimer_delete(tmr);
877 }
878 }
880 /* Not available / possible... functions */
881 int do_posix_clock_nosettime(const clockid_t clockid, struct timespec *tp)
882 {
883 return -EINVAL;
884 }
885 EXPORT_SYMBOL_GPL(do_posix_clock_nosettime);
887 int do_posix_clock_nonanosleep(const clockid_t clock, int flags,
888 struct timespec *t, struct timespec __user *r)
889 {
890 #ifndef ENOTSUP
891 return -EOPNOTSUPP; /* aka ENOTSUP in userland for POSIX */
892 #else /* parisc does define it separately. */
893 return -ENOTSUP;
894 #endif
895 }
896 EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep);
898 asmlinkage long sys_clock_settime(const clockid_t which_clock,
899 const struct timespec __user *tp)
900 {
901 struct timespec new_tp;
903 if (invalid_clockid(which_clock))
904 return -EINVAL;
905 if (copy_from_user(&new_tp, tp, sizeof (*tp)))
906 return -EFAULT;
908 return CLOCK_DISPATCH(which_clock, clock_set, (which_clock, &new_tp));
909 }
911 asmlinkage long
912 sys_clock_gettime(const clockid_t which_clock, struct timespec __user *tp)
913 {
914 struct timespec kernel_tp;
915 int error;
917 if (invalid_clockid(which_clock))
918 return -EINVAL;
919 error = CLOCK_DISPATCH(which_clock, clock_get,
920 (which_clock, &kernel_tp));
921 if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
922 error = -EFAULT;
924 return error;
926 }
928 asmlinkage long
929 sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
930 {
931 struct timespec rtn_tp;
932 int error;
934 if (invalid_clockid(which_clock))
935 return -EINVAL;
937 error = CLOCK_DISPATCH(which_clock, clock_getres,
938 (which_clock, &rtn_tp));
940 if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) {
941 error = -EFAULT;
942 }
944 return error;
945 }
947 /*
948 * nanosleep for monotonic and realtime clocks
949 */
950 static int common_nsleep(const clockid_t which_clock, int flags,
951 struct timespec *tsave, struct timespec __user *rmtp)
952 {
953 return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
954 HRTIMER_ABS : HRTIMER_REL, which_clock);
955 }
957 asmlinkage long
958 sys_clock_nanosleep(const clockid_t which_clock, int flags,
959 const struct timespec __user *rqtp,
960 struct timespec __user *rmtp)
961 {
962 struct timespec t;
964 if (invalid_clockid(which_clock))
965 return -EINVAL;
967 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
968 return -EFAULT;
970 if (!timespec_valid(&t))
971 return -EINVAL;
973 return CLOCK_DISPATCH(which_clock, nsleep,
974 (which_clock, flags, &t, rmtp));
975 }