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1 | /* |
2 | * linux/kernel/posix-timers.c |
3 | * |
4 | * |
5 | * 2002-10-15 Posix Clocks & timers |
6 | * by George Anzinger george@mvista.com |
7 | * |
8 | * Copyright (C) 2002 2003 by MontaVista Software. |
9 | * |
10 | * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug. |
11 | * Copyright (C) 2004 Boris Hu |
12 | * |
13 | * This program is free software; you can redistribute it and/or modify |
14 | * it under the terms of the GNU General Public License as published by |
15 | * the Free Software Foundation; either version 2 of the License, or (at |
16 | * your option) any later version. |
17 | * |
18 | * This program is distributed in the hope that it will be useful, but |
19 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
21 | * General Public License for more details. |
22 | |
23 | * You should have received a copy of the GNU General Public License |
24 | * along with this program; if not, write to the Free Software |
25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
26 | * |
27 | * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA |
28 | */ |
29 | |
30 | /* These are all the functions necessary to implement |
31 | * POSIX clocks & timers |
32 | */ |
33 | #include <linux/mm.h> |
34 | #include <linux/interrupt.h> |
35 | #include <linux/slab.h> |
36 | #include <linux/time.h> |
37 | #include <linux/mutex.h> |
38 | |
39 | #include <asm/uaccess.h> |
40 | #include <linux/list.h> |
41 | #include <linux/init.h> |
42 | #include <linux/compiler.h> |
43 | #include <linux/idr.h> |
44 | #include <linux/posix-clock.h> |
45 | #include <linux/posix-timers.h> |
46 | #include <linux/syscalls.h> |
47 | #include <linux/wait.h> |
48 | #include <linux/workqueue.h> |
49 | #include <linux/module.h> |
50 | |
51 | /* |
52 | * Management arrays for POSIX timers. Timers are kept in slab memory |
53 | * Timer ids are allocated by an external routine that keeps track of the |
54 | * id and the timer. The external interface is: |
55 | * |
56 | * void *idr_find(struct idr *idp, int id); to find timer_id <id> |
57 | * int idr_get_new(struct idr *idp, void *ptr); to get a new id and |
58 | * related it to <ptr> |
59 | * void idr_remove(struct idr *idp, int id); to release <id> |
60 | * void idr_init(struct idr *idp); to initialize <idp> |
61 | * which we supply. |
62 | * The idr_get_new *may* call slab for more memory so it must not be |
63 | * called under a spin lock. Likewise idr_remore may release memory |
64 | * (but it may be ok to do this under a lock...). |
65 | * idr_find is just a memory look up and is quite fast. A -1 return |
66 | * indicates that the requested id does not exist. |
67 | */ |
68 | |
69 | /* |
70 | * Lets keep our timers in a slab cache :-) |
71 | */ |
72 | static struct kmem_cache *posix_timers_cache; |
73 | static struct idr posix_timers_id; |
74 | static DEFINE_SPINLOCK(idr_lock); |
75 | |
76 | /* |
77 | * we assume that the new SIGEV_THREAD_ID shares no bits with the other |
78 | * SIGEV values. Here we put out an error if this assumption fails. |
79 | */ |
80 | #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \ |
81 | ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD)) |
82 | #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!" |
83 | #endif |
84 | |
85 | /* |
86 | * parisc wants ENOTSUP instead of EOPNOTSUPP |
87 | */ |
88 | #ifndef ENOTSUP |
89 | # define ENANOSLEEP_NOTSUP EOPNOTSUPP |
90 | #else |
91 | # define ENANOSLEEP_NOTSUP ENOTSUP |
92 | #endif |
93 | |
94 | /* |
95 | * The timer ID is turned into a timer address by idr_find(). |
96 | * Verifying a valid ID consists of: |
97 | * |
98 | * a) checking that idr_find() returns other than -1. |
99 | * b) checking that the timer id matches the one in the timer itself. |
100 | * c) that the timer owner is in the callers thread group. |
101 | */ |
102 | |
103 | /* |
104 | * CLOCKs: The POSIX standard calls for a couple of clocks and allows us |
105 | * to implement others. This structure defines the various |
106 | * clocks. |
107 | * |
108 | * RESOLUTION: Clock resolution is used to round up timer and interval |
109 | * times, NOT to report clock times, which are reported with as |
110 | * much resolution as the system can muster. In some cases this |
111 | * resolution may depend on the underlying clock hardware and |
112 | * may not be quantifiable until run time, and only then is the |
113 | * necessary code is written. The standard says we should say |
114 | * something about this issue in the documentation... |
115 | * |
116 | * FUNCTIONS: The CLOCKs structure defines possible functions to |
117 | * handle various clock functions. |
118 | * |
119 | * The standard POSIX timer management code assumes the |
120 | * following: 1.) The k_itimer struct (sched.h) is used for |
121 | * the timer. 2.) The list, it_lock, it_clock, it_id and |
122 | * it_pid fields are not modified by timer code. |
123 | * |
124 | * Permissions: It is assumed that the clock_settime() function defined |
125 | * for each clock will take care of permission checks. Some |
126 | * clocks may be set able by any user (i.e. local process |
127 | * clocks) others not. Currently the only set able clock we |
128 | * have is CLOCK_REALTIME and its high res counter part, both of |
129 | * which we beg off on and pass to do_sys_settimeofday(). |
130 | */ |
131 | |
132 | static struct k_clock posix_clocks[MAX_CLOCKS]; |
133 | |
134 | /* |
135 | * These ones are defined below. |
136 | */ |
137 | static int common_nsleep(const clockid_t, int flags, struct timespec *t, |
138 | struct timespec __user *rmtp); |
139 | static int common_timer_create(struct k_itimer *new_timer); |
140 | static void common_timer_get(struct k_itimer *, struct itimerspec *); |
141 | static int common_timer_set(struct k_itimer *, int, |
142 | struct itimerspec *, struct itimerspec *); |
143 | static int common_timer_del(struct k_itimer *timer); |
144 | |
145 | static enum hrtimer_restart posix_timer_fn(struct hrtimer *data); |
146 | |
147 | static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags); |
148 | |
149 | #define lock_timer(tid, flags) \ |
150 | ({ struct k_itimer *__timr; \ |
151 | __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \ |
152 | __timr; \ |
153 | }) |
154 | |
155 | static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) |
156 | { |
157 | spin_unlock_irqrestore(&timr->it_lock, flags); |
158 | } |
159 | |
160 | /* Get clock_realtime */ |
161 | static int posix_clock_realtime_get(clockid_t which_clock, struct timespec *tp) |
162 | { |
163 | ktime_get_real_ts(tp); |
164 | return 0; |
165 | } |
166 | |
167 | /* Set clock_realtime */ |
168 | static int posix_clock_realtime_set(const clockid_t which_clock, |
169 | const struct timespec *tp) |
170 | { |
171 | return do_sys_settimeofday(tp, NULL); |
172 | } |
173 | |
174 | static int posix_clock_realtime_adj(const clockid_t which_clock, |
175 | struct timex *t) |
176 | { |
177 | return do_adjtimex(t); |
178 | } |
179 | |
180 | /* |
181 | * Get monotonic time for posix timers |
182 | */ |
183 | static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp) |
184 | { |
185 | ktime_get_ts(tp); |
186 | return 0; |
187 | } |
188 | |
189 | /* |
190 | * Get monotonic-raw time for posix timers |
191 | */ |
192 | static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp) |
193 | { |
194 | getrawmonotonic(tp); |
195 | return 0; |
196 | } |
197 | |
198 | |
199 | static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp) |
200 | { |
201 | *tp = current_kernel_time(); |
202 | return 0; |
203 | } |
204 | |
205 | static int posix_get_monotonic_coarse(clockid_t which_clock, |
206 | struct timespec *tp) |
207 | { |
208 | *tp = get_monotonic_coarse(); |
209 | return 0; |
210 | } |
211 | |
212 | static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp) |
213 | { |
214 | *tp = ktime_to_timespec(KTIME_LOW_RES); |
215 | return 0; |
216 | } |
217 | |
218 | static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp) |
219 | { |
220 | get_monotonic_boottime(tp); |
221 | return 0; |
222 | } |
223 | |
224 | |
225 | /* |
226 | * Initialize everything, well, just everything in Posix clocks/timers ;) |
227 | */ |
228 | static __init int init_posix_timers(void) |
229 | { |
230 | struct k_clock clock_realtime = { |
231 | .clock_getres = hrtimer_get_res, |
232 | .clock_get = posix_clock_realtime_get, |
233 | .clock_set = posix_clock_realtime_set, |
234 | .clock_adj = posix_clock_realtime_adj, |
235 | .nsleep = common_nsleep, |
236 | .nsleep_restart = hrtimer_nanosleep_restart, |
237 | .timer_create = common_timer_create, |
238 | .timer_set = common_timer_set, |
239 | .timer_get = common_timer_get, |
240 | .timer_del = common_timer_del, |
241 | }; |
242 | struct k_clock clock_monotonic = { |
243 | .clock_getres = hrtimer_get_res, |
244 | .clock_get = posix_ktime_get_ts, |
245 | .nsleep = common_nsleep, |
246 | .nsleep_restart = hrtimer_nanosleep_restart, |
247 | .timer_create = common_timer_create, |
248 | .timer_set = common_timer_set, |
249 | .timer_get = common_timer_get, |
250 | .timer_del = common_timer_del, |
251 | }; |
252 | struct k_clock clock_monotonic_raw = { |
253 | .clock_getres = hrtimer_get_res, |
254 | .clock_get = posix_get_monotonic_raw, |
255 | }; |
256 | struct k_clock clock_realtime_coarse = { |
257 | .clock_getres = posix_get_coarse_res, |
258 | .clock_get = posix_get_realtime_coarse, |
259 | }; |
260 | struct k_clock clock_monotonic_coarse = { |
261 | .clock_getres = posix_get_coarse_res, |
262 | .clock_get = posix_get_monotonic_coarse, |
263 | }; |
264 | struct k_clock clock_boottime = { |
265 | .clock_getres = hrtimer_get_res, |
266 | .clock_get = posix_get_boottime, |
267 | .nsleep = common_nsleep, |
268 | .nsleep_restart = hrtimer_nanosleep_restart, |
269 | .timer_create = common_timer_create, |
270 | .timer_set = common_timer_set, |
271 | .timer_get = common_timer_get, |
272 | .timer_del = common_timer_del, |
273 | }; |
274 | |
275 | posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime); |
276 | posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic); |
277 | posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw); |
278 | posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse); |
279 | posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse); |
280 | posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime); |
281 | |
282 | posix_timers_cache = kmem_cache_create("posix_timers_cache", |
283 | sizeof (struct k_itimer), 0, SLAB_PANIC, |
284 | NULL); |
285 | idr_init(&posix_timers_id); |
286 | return 0; |
287 | } |
288 | |
289 | __initcall(init_posix_timers); |
290 | |
291 | static void schedule_next_timer(struct k_itimer *timr) |
292 | { |
293 | struct hrtimer *timer = &timr->it.real.timer; |
294 | |
295 | if (timr->it.real.interval.tv64 == 0) |
296 | return; |
297 | |
298 | timr->it_overrun += (unsigned int) hrtimer_forward(timer, |
299 | timer->base->get_time(), |
300 | timr->it.real.interval); |
301 | |
302 | timr->it_overrun_last = timr->it_overrun; |
303 | timr->it_overrun = -1; |
304 | ++timr->it_requeue_pending; |
305 | hrtimer_restart(timer); |
306 | } |
307 | |
308 | /* |
309 | * This function is exported for use by the signal deliver code. It is |
310 | * called just prior to the info block being released and passes that |
311 | * block to us. It's function is to update the overrun entry AND to |
312 | * restart the timer. It should only be called if the timer is to be |
313 | * restarted (i.e. we have flagged this in the sys_private entry of the |
314 | * info block). |
315 | * |
316 | * To protect against the timer going away while the interrupt is queued, |
317 | * we require that the it_requeue_pending flag be set. |
318 | */ |
319 | void do_schedule_next_timer(struct siginfo *info) |
320 | { |
321 | struct k_itimer *timr; |
322 | unsigned long flags; |
323 | |
324 | timr = lock_timer(info->si_tid, &flags); |
325 | |
326 | if (timr && timr->it_requeue_pending == info->si_sys_private) { |
327 | if (timr->it_clock < 0) |
328 | posix_cpu_timer_schedule(timr); |
329 | else |
330 | schedule_next_timer(timr); |
331 | |
332 | info->si_overrun += timr->it_overrun_last; |
333 | } |
334 | |
335 | if (timr) |
336 | unlock_timer(timr, flags); |
337 | } |
338 | |
339 | int posix_timer_event(struct k_itimer *timr, int si_private) |
340 | { |
341 | struct task_struct *task; |
342 | int shared, ret = -1; |
343 | /* |
344 | * FIXME: if ->sigq is queued we can race with |
345 | * dequeue_signal()->do_schedule_next_timer(). |
346 | * |
347 | * If dequeue_signal() sees the "right" value of |
348 | * si_sys_private it calls do_schedule_next_timer(). |
349 | * We re-queue ->sigq and drop ->it_lock(). |
350 | * do_schedule_next_timer() locks the timer |
351 | * and re-schedules it while ->sigq is pending. |
352 | * Not really bad, but not that we want. |
353 | */ |
354 | timr->sigq->info.si_sys_private = si_private; |
355 | |
356 | rcu_read_lock(); |
357 | task = pid_task(timr->it_pid, PIDTYPE_PID); |
358 | if (task) { |
359 | shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); |
360 | ret = send_sigqueue(timr->sigq, task, shared); |
361 | } |
362 | rcu_read_unlock(); |
363 | /* If we failed to send the signal the timer stops. */ |
364 | return ret > 0; |
365 | } |
366 | EXPORT_SYMBOL_GPL(posix_timer_event); |
367 | |
368 | /* |
369 | * This function gets called when a POSIX.1b interval timer expires. It |
370 | * is used as a callback from the kernel internal timer. The |
371 | * run_timer_list code ALWAYS calls with interrupts on. |
372 | |
373 | * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers. |
374 | */ |
375 | static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer) |
376 | { |
377 | struct k_itimer *timr; |
378 | unsigned long flags; |
379 | int si_private = 0; |
380 | enum hrtimer_restart ret = HRTIMER_NORESTART; |
381 | |
382 | timr = container_of(timer, struct k_itimer, it.real.timer); |
383 | spin_lock_irqsave(&timr->it_lock, flags); |
384 | |
385 | if (timr->it.real.interval.tv64 != 0) |
386 | si_private = ++timr->it_requeue_pending; |
387 | |
388 | if (posix_timer_event(timr, si_private)) { |
389 | /* |
390 | * signal was not sent because of sig_ignor |
391 | * we will not get a call back to restart it AND |
392 | * it should be restarted. |
393 | */ |
394 | if (timr->it.real.interval.tv64 != 0) { |
395 | ktime_t now = hrtimer_cb_get_time(timer); |
396 | |
397 | /* |
398 | * FIXME: What we really want, is to stop this |
399 | * timer completely and restart it in case the |
400 | * SIG_IGN is removed. This is a non trivial |
401 | * change which involves sighand locking |
402 | * (sigh !), which we don't want to do late in |
403 | * the release cycle. |
404 | * |
405 | * For now we just let timers with an interval |
406 | * less than a jiffie expire every jiffie to |
407 | * avoid softirq starvation in case of SIG_IGN |
408 | * and a very small interval, which would put |
409 | * the timer right back on the softirq pending |
410 | * list. By moving now ahead of time we trick |
411 | * hrtimer_forward() to expire the timer |
412 | * later, while we still maintain the overrun |
413 | * accuracy, but have some inconsistency in |
414 | * the timer_gettime() case. This is at least |
415 | * better than a starved softirq. A more |
416 | * complex fix which solves also another related |
417 | * inconsistency is already in the pipeline. |
418 | */ |
419 | #ifdef CONFIG_HIGH_RES_TIMERS |
420 | { |
421 | ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ); |
422 | |
423 | if (timr->it.real.interval.tv64 < kj.tv64) |
424 | now = ktime_add(now, kj); |
425 | } |
426 | #endif |
427 | timr->it_overrun += (unsigned int) |
428 | hrtimer_forward(timer, now, |
429 | timr->it.real.interval); |
430 | ret = HRTIMER_RESTART; |
431 | ++timr->it_requeue_pending; |
432 | } |
433 | } |
434 | |
435 | unlock_timer(timr, flags); |
436 | return ret; |
437 | } |
438 | |
439 | static struct pid *good_sigevent(sigevent_t * event) |
440 | { |
441 | struct task_struct *rtn = current->group_leader; |
442 | |
443 | if ((event->sigev_notify & SIGEV_THREAD_ID ) && |
444 | (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) || |
445 | !same_thread_group(rtn, current) || |
446 | (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) |
447 | return NULL; |
448 | |
449 | if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) && |
450 | ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX))) |
451 | return NULL; |
452 | |
453 | return task_pid(rtn); |
454 | } |
455 | |
456 | void posix_timers_register_clock(const clockid_t clock_id, |
457 | struct k_clock *new_clock) |
458 | { |
459 | if ((unsigned) clock_id >= MAX_CLOCKS) { |
460 | printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n", |
461 | clock_id); |
462 | return; |
463 | } |
464 | |
465 | if (!new_clock->clock_get) { |
466 | printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n", |
467 | clock_id); |
468 | return; |
469 | } |
470 | if (!new_clock->clock_getres) { |
471 | printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n", |
472 | clock_id); |
473 | return; |
474 | } |
475 | |
476 | posix_clocks[clock_id] = *new_clock; |
477 | } |
478 | EXPORT_SYMBOL_GPL(posix_timers_register_clock); |
479 | |
480 | static struct k_itimer * alloc_posix_timer(void) |
481 | { |
482 | struct k_itimer *tmr; |
483 | tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL); |
484 | if (!tmr) |
485 | return tmr; |
486 | if (unlikely(!(tmr->sigq = sigqueue_alloc()))) { |
487 | kmem_cache_free(posix_timers_cache, tmr); |
488 | return NULL; |
489 | } |
490 | memset(&tmr->sigq->info, 0, sizeof(siginfo_t)); |
491 | return tmr; |
492 | } |
493 | |
494 | static void k_itimer_rcu_free(struct rcu_head *head) |
495 | { |
496 | struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu); |
497 | |
498 | kmem_cache_free(posix_timers_cache, tmr); |
499 | } |
500 | |
501 | #define IT_ID_SET 1 |
502 | #define IT_ID_NOT_SET 0 |
503 | static void release_posix_timer(struct k_itimer *tmr, int it_id_set) |
504 | { |
505 | if (it_id_set) { |
506 | unsigned long flags; |
507 | spin_lock_irqsave(&idr_lock, flags); |
508 | idr_remove(&posix_timers_id, tmr->it_id); |
509 | spin_unlock_irqrestore(&idr_lock, flags); |
510 | } |
511 | put_pid(tmr->it_pid); |
512 | sigqueue_free(tmr->sigq); |
513 | call_rcu(&tmr->it.rcu, k_itimer_rcu_free); |
514 | } |
515 | |
516 | static struct k_clock *clockid_to_kclock(const clockid_t id) |
517 | { |
518 | if (id < 0) |
519 | return (id & CLOCKFD_MASK) == CLOCKFD ? |
520 | &clock_posix_dynamic : &clock_posix_cpu; |
521 | |
522 | if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres) |
523 | return NULL; |
524 | return &posix_clocks[id]; |
525 | } |
526 | |
527 | static int common_timer_create(struct k_itimer *new_timer) |
528 | { |
529 | hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0); |
530 | return 0; |
531 | } |
532 | |
533 | /* Create a POSIX.1b interval timer. */ |
534 | |
535 | SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, |
536 | struct sigevent __user *, timer_event_spec, |
537 | timer_t __user *, created_timer_id) |
538 | { |
539 | struct k_clock *kc = clockid_to_kclock(which_clock); |
540 | struct k_itimer *new_timer; |
541 | int error, new_timer_id; |
542 | sigevent_t event; |
543 | int it_id_set = IT_ID_NOT_SET; |
544 | |
545 | if (!kc) |
546 | return -EINVAL; |
547 | if (!kc->timer_create) |
548 | return -EOPNOTSUPP; |
549 | |
550 | new_timer = alloc_posix_timer(); |
551 | if (unlikely(!new_timer)) |
552 | return -EAGAIN; |
553 | |
554 | spin_lock_init(&new_timer->it_lock); |
555 | retry: |
556 | if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) { |
557 | error = -EAGAIN; |
558 | goto out; |
559 | } |
560 | spin_lock_irq(&idr_lock); |
561 | error = idr_get_new(&posix_timers_id, new_timer, &new_timer_id); |
562 | spin_unlock_irq(&idr_lock); |
563 | if (error) { |
564 | if (error == -EAGAIN) |
565 | goto retry; |
566 | /* |
567 | * Weird looking, but we return EAGAIN if the IDR is |
568 | * full (proper POSIX return value for this) |
569 | */ |
570 | error = -EAGAIN; |
571 | goto out; |
572 | } |
573 | |
574 | it_id_set = IT_ID_SET; |
575 | new_timer->it_id = (timer_t) new_timer_id; |
576 | new_timer->it_clock = which_clock; |
577 | new_timer->it_overrun = -1; |
578 | |
579 | if (timer_event_spec) { |
580 | if (copy_from_user(&event, timer_event_spec, sizeof (event))) { |
581 | error = -EFAULT; |
582 | goto out; |
583 | } |
584 | rcu_read_lock(); |
585 | new_timer->it_pid = get_pid(good_sigevent(&event)); |
586 | rcu_read_unlock(); |
587 | if (!new_timer->it_pid) { |
588 | error = -EINVAL; |
589 | goto out; |
590 | } |
591 | } else { |
592 | event.sigev_notify = SIGEV_SIGNAL; |
593 | event.sigev_signo = SIGALRM; |
594 | event.sigev_value.sival_int = new_timer->it_id; |
595 | new_timer->it_pid = get_pid(task_tgid(current)); |
596 | } |
597 | |
598 | new_timer->it_sigev_notify = event.sigev_notify; |
599 | new_timer->sigq->info.si_signo = event.sigev_signo; |
600 | new_timer->sigq->info.si_value = event.sigev_value; |
601 | new_timer->sigq->info.si_tid = new_timer->it_id; |
602 | new_timer->sigq->info.si_code = SI_TIMER; |
603 | |
604 | if (copy_to_user(created_timer_id, |
605 | &new_timer_id, sizeof (new_timer_id))) { |
606 | error = -EFAULT; |
607 | goto out; |
608 | } |
609 | |
610 | error = kc->timer_create(new_timer); |
611 | if (error) |
612 | goto out; |
613 | |
614 | spin_lock_irq(¤t->sighand->siglock); |
615 | new_timer->it_signal = current->signal; |
616 | list_add(&new_timer->list, ¤t->signal->posix_timers); |
617 | spin_unlock_irq(¤t->sighand->siglock); |
618 | |
619 | return 0; |
620 | /* |
621 | * In the case of the timer belonging to another task, after |
622 | * the task is unlocked, the timer is owned by the other task |
623 | * and may cease to exist at any time. Don't use or modify |
624 | * new_timer after the unlock call. |
625 | */ |
626 | out: |
627 | release_posix_timer(new_timer, it_id_set); |
628 | return error; |
629 | } |
630 | |
631 | /* |
632 | * Locking issues: We need to protect the result of the id look up until |
633 | * we get the timer locked down so it is not deleted under us. The |
634 | * removal is done under the idr spinlock so we use that here to bridge |
635 | * the find to the timer lock. To avoid a dead lock, the timer id MUST |
636 | * be release with out holding the timer lock. |
637 | */ |
638 | static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) |
639 | { |
640 | struct k_itimer *timr; |
641 | |
642 | rcu_read_lock(); |
643 | timr = idr_find(&posix_timers_id, (int)timer_id); |
644 | if (timr) { |
645 | spin_lock_irqsave(&timr->it_lock, *flags); |
646 | if (timr->it_signal == current->signal) { |
647 | rcu_read_unlock(); |
648 | return timr; |
649 | } |
650 | spin_unlock_irqrestore(&timr->it_lock, *flags); |
651 | } |
652 | rcu_read_unlock(); |
653 | |
654 | return NULL; |
655 | } |
656 | |
657 | /* |
658 | * Get the time remaining on a POSIX.1b interval timer. This function |
659 | * is ALWAYS called with spin_lock_irq on the timer, thus it must not |
660 | * mess with irq. |
661 | * |
662 | * We have a couple of messes to clean up here. First there is the case |
663 | * of a timer that has a requeue pending. These timers should appear to |
664 | * be in the timer list with an expiry as if we were to requeue them |
665 | * now. |
666 | * |
667 | * The second issue is the SIGEV_NONE timer which may be active but is |
668 | * not really ever put in the timer list (to save system resources). |
669 | * This timer may be expired, and if so, we will do it here. Otherwise |
670 | * it is the same as a requeue pending timer WRT to what we should |
671 | * report. |
672 | */ |
673 | static void |
674 | common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) |
675 | { |
676 | ktime_t now, remaining, iv; |
677 | struct hrtimer *timer = &timr->it.real.timer; |
678 | |
679 | memset(cur_setting, 0, sizeof(struct itimerspec)); |
680 | |
681 | iv = timr->it.real.interval; |
682 | |
683 | /* interval timer ? */ |
684 | if (iv.tv64) |
685 | cur_setting->it_interval = ktime_to_timespec(iv); |
686 | else if (!hrtimer_active(timer) && |
687 | (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) |
688 | return; |
689 | |
690 | now = timer->base->get_time(); |
691 | |
692 | /* |
693 | * When a requeue is pending or this is a SIGEV_NONE |
694 | * timer move the expiry time forward by intervals, so |
695 | * expiry is > now. |
696 | */ |
697 | if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || |
698 | (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) |
699 | timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); |
700 | |
701 | remaining = ktime_sub(hrtimer_get_expires(timer), now); |
702 | /* Return 0 only, when the timer is expired and not pending */ |
703 | if (remaining.tv64 <= 0) { |
704 | /* |
705 | * A single shot SIGEV_NONE timer must return 0, when |
706 | * it is expired ! |
707 | */ |
708 | if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) |
709 | cur_setting->it_value.tv_nsec = 1; |
710 | } else |
711 | cur_setting->it_value = ktime_to_timespec(remaining); |
712 | } |
713 | |
714 | /* Get the time remaining on a POSIX.1b interval timer. */ |
715 | SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id, |
716 | struct itimerspec __user *, setting) |
717 | { |
718 | struct itimerspec cur_setting; |
719 | struct k_itimer *timr; |
720 | struct k_clock *kc; |
721 | unsigned long flags; |
722 | int ret = 0; |
723 | |
724 | timr = lock_timer(timer_id, &flags); |
725 | if (!timr) |
726 | return -EINVAL; |
727 | |
728 | kc = clockid_to_kclock(timr->it_clock); |
729 | if (WARN_ON_ONCE(!kc || !kc->timer_get)) |
730 | ret = -EINVAL; |
731 | else |
732 | kc->timer_get(timr, &cur_setting); |
733 | |
734 | unlock_timer(timr, flags); |
735 | |
736 | if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting))) |
737 | return -EFAULT; |
738 | |
739 | return ret; |
740 | } |
741 | |
742 | /* |
743 | * Get the number of overruns of a POSIX.1b interval timer. This is to |
744 | * be the overrun of the timer last delivered. At the same time we are |
745 | * accumulating overruns on the next timer. The overrun is frozen when |
746 | * the signal is delivered, either at the notify time (if the info block |
747 | * is not queued) or at the actual delivery time (as we are informed by |
748 | * the call back to do_schedule_next_timer(). So all we need to do is |
749 | * to pick up the frozen overrun. |
750 | */ |
751 | SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) |
752 | { |
753 | struct k_itimer *timr; |
754 | int overrun; |
755 | unsigned long flags; |
756 | |
757 | timr = lock_timer(timer_id, &flags); |
758 | if (!timr) |
759 | return -EINVAL; |
760 | |
761 | overrun = timr->it_overrun_last; |
762 | unlock_timer(timr, flags); |
763 | |
764 | return overrun; |
765 | } |
766 | |
767 | /* Set a POSIX.1b interval timer. */ |
768 | /* timr->it_lock is taken. */ |
769 | static int |
770 | common_timer_set(struct k_itimer *timr, int flags, |
771 | struct itimerspec *new_setting, struct itimerspec *old_setting) |
772 | { |
773 | struct hrtimer *timer = &timr->it.real.timer; |
774 | enum hrtimer_mode mode; |
775 | |
776 | if (old_setting) |
777 | common_timer_get(timr, old_setting); |
778 | |
779 | /* disable the timer */ |
780 | timr->it.real.interval.tv64 = 0; |
781 | /* |
782 | * careful here. If smp we could be in the "fire" routine which will |
783 | * be spinning as we hold the lock. But this is ONLY an SMP issue. |
784 | */ |
785 | if (hrtimer_try_to_cancel(timer) < 0) |
786 | return TIMER_RETRY; |
787 | |
788 | timr->it_requeue_pending = (timr->it_requeue_pending + 2) & |
789 | ~REQUEUE_PENDING; |
790 | timr->it_overrun_last = 0; |
791 | |
792 | /* switch off the timer when it_value is zero */ |
793 | if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) |
794 | return 0; |
795 | |
796 | mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; |
797 | hrtimer_init(&timr->it.real.timer, timr->it_clock, mode); |
798 | timr->it.real.timer.function = posix_timer_fn; |
799 | |
800 | hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value)); |
801 | |
802 | /* Convert interval */ |
803 | timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); |
804 | |
805 | /* SIGEV_NONE timers are not queued ! See common_timer_get */ |
806 | if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { |
807 | /* Setup correct expiry time for relative timers */ |
808 | if (mode == HRTIMER_MODE_REL) { |
809 | hrtimer_add_expires(timer, timer->base->get_time()); |
810 | } |
811 | return 0; |
812 | } |
813 | |
814 | hrtimer_start_expires(timer, mode); |
815 | return 0; |
816 | } |
817 | |
818 | /* Set a POSIX.1b interval timer */ |
819 | SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, |
820 | const struct itimerspec __user *, new_setting, |
821 | struct itimerspec __user *, old_setting) |
822 | { |
823 | struct k_itimer *timr; |
824 | struct itimerspec new_spec, old_spec; |
825 | int error = 0; |
826 | unsigned long flag; |
827 | struct itimerspec *rtn = old_setting ? &old_spec : NULL; |
828 | struct k_clock *kc; |
829 | |
830 | if (!new_setting) |
831 | return -EINVAL; |
832 | |
833 | if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) |
834 | return -EFAULT; |
835 | |
836 | if (!timespec_valid(&new_spec.it_interval) || |
837 | !timespec_valid(&new_spec.it_value)) |
838 | return -EINVAL; |
839 | retry: |
840 | timr = lock_timer(timer_id, &flag); |
841 | if (!timr) |
842 | return -EINVAL; |
843 | |
844 | kc = clockid_to_kclock(timr->it_clock); |
845 | if (WARN_ON_ONCE(!kc || !kc->timer_set)) |
846 | error = -EINVAL; |
847 | else |
848 | error = kc->timer_set(timr, flags, &new_spec, rtn); |
849 | |
850 | unlock_timer(timr, flag); |
851 | if (error == TIMER_RETRY) { |
852 | rtn = NULL; // We already got the old time... |
853 | goto retry; |
854 | } |
855 | |
856 | if (old_setting && !error && |
857 | copy_to_user(old_setting, &old_spec, sizeof (old_spec))) |
858 | error = -EFAULT; |
859 | |
860 | return error; |
861 | } |
862 | |
863 | static int common_timer_del(struct k_itimer *timer) |
864 | { |
865 | timer->it.real.interval.tv64 = 0; |
866 | |
867 | if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0) |
868 | return TIMER_RETRY; |
869 | return 0; |
870 | } |
871 | |
872 | static inline int timer_delete_hook(struct k_itimer *timer) |
873 | { |
874 | struct k_clock *kc = clockid_to_kclock(timer->it_clock); |
875 | |
876 | if (WARN_ON_ONCE(!kc || !kc->timer_del)) |
877 | return -EINVAL; |
878 | return kc->timer_del(timer); |
879 | } |
880 | |
881 | /* Delete a POSIX.1b interval timer. */ |
882 | SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) |
883 | { |
884 | struct k_itimer *timer; |
885 | unsigned long flags; |
886 | |
887 | retry_delete: |
888 | timer = lock_timer(timer_id, &flags); |
889 | if (!timer) |
890 | return -EINVAL; |
891 | |
892 | if (timer_delete_hook(timer) == TIMER_RETRY) { |
893 | unlock_timer(timer, flags); |
894 | goto retry_delete; |
895 | } |
896 | |
897 | spin_lock(¤t->sighand->siglock); |
898 | list_del(&timer->list); |
899 | spin_unlock(¤t->sighand->siglock); |
900 | /* |
901 | * This keeps any tasks waiting on the spin lock from thinking |
902 | * they got something (see the lock code above). |
903 | */ |
904 | timer->it_signal = NULL; |
905 | |
906 | unlock_timer(timer, flags); |
907 | release_posix_timer(timer, IT_ID_SET); |
908 | return 0; |
909 | } |
910 | |
911 | /* |
912 | * return timer owned by the process, used by exit_itimers |
913 | */ |
914 | static void itimer_delete(struct k_itimer *timer) |
915 | { |
916 | unsigned long flags; |
917 | |
918 | retry_delete: |
919 | spin_lock_irqsave(&timer->it_lock, flags); |
920 | |
921 | if (timer_delete_hook(timer) == TIMER_RETRY) { |
922 | unlock_timer(timer, flags); |
923 | goto retry_delete; |
924 | } |
925 | list_del(&timer->list); |
926 | /* |
927 | * This keeps any tasks waiting on the spin lock from thinking |
928 | * they got something (see the lock code above). |
929 | */ |
930 | timer->it_signal = NULL; |
931 | |
932 | unlock_timer(timer, flags); |
933 | release_posix_timer(timer, IT_ID_SET); |
934 | } |
935 | |
936 | /* |
937 | * This is called by do_exit or de_thread, only when there are no more |
938 | * references to the shared signal_struct. |
939 | */ |
940 | void exit_itimers(struct signal_struct *sig) |
941 | { |
942 | struct k_itimer *tmr; |
943 | |
944 | while (!list_empty(&sig->posix_timers)) { |
945 | tmr = list_entry(sig->posix_timers.next, struct k_itimer, list); |
946 | itimer_delete(tmr); |
947 | } |
948 | } |
949 | |
950 | SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, |
951 | const struct timespec __user *, tp) |
952 | { |
953 | struct k_clock *kc = clockid_to_kclock(which_clock); |
954 | struct timespec new_tp; |
955 | |
956 | if (!kc || !kc->clock_set) |
957 | return -EINVAL; |
958 | |
959 | if (copy_from_user(&new_tp, tp, sizeof (*tp))) |
960 | return -EFAULT; |
961 | |
962 | return kc->clock_set(which_clock, &new_tp); |
963 | } |
964 | |
965 | SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, |
966 | struct timespec __user *,tp) |
967 | { |
968 | struct k_clock *kc = clockid_to_kclock(which_clock); |
969 | struct timespec kernel_tp; |
970 | int error; |
971 | |
972 | if (!kc) |
973 | return -EINVAL; |
974 | |
975 | error = kc->clock_get(which_clock, &kernel_tp); |
976 | |
977 | if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) |
978 | error = -EFAULT; |
979 | |
980 | return error; |
981 | } |
982 | |
983 | SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock, |
984 | struct timex __user *, utx) |
985 | { |
986 | struct k_clock *kc = clockid_to_kclock(which_clock); |
987 | struct timex ktx; |
988 | int err; |
989 | |
990 | if (!kc) |
991 | return -EINVAL; |
992 | if (!kc->clock_adj) |
993 | return -EOPNOTSUPP; |
994 | |
995 | if (copy_from_user(&ktx, utx, sizeof(ktx))) |
996 | return -EFAULT; |
997 | |
998 | err = kc->clock_adj(which_clock, &ktx); |
999 | |
1000 | if (!err && copy_to_user(utx, &ktx, sizeof(ktx))) |
1001 | return -EFAULT; |
1002 | |
1003 | return err; |
1004 | } |
1005 | |
1006 | SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, |
1007 | struct timespec __user *, tp) |
1008 | { |
1009 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1010 | struct timespec rtn_tp; |
1011 | int error; |
1012 | |
1013 | if (!kc) |
1014 | return -EINVAL; |
1015 | |
1016 | error = kc->clock_getres(which_clock, &rtn_tp); |
1017 | |
1018 | if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) |
1019 | error = -EFAULT; |
1020 | |
1021 | return error; |
1022 | } |
1023 | |
1024 | /* |
1025 | * nanosleep for monotonic and realtime clocks |
1026 | */ |
1027 | static int common_nsleep(const clockid_t which_clock, int flags, |
1028 | struct timespec *tsave, struct timespec __user *rmtp) |
1029 | { |
1030 | return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ? |
1031 | HRTIMER_MODE_ABS : HRTIMER_MODE_REL, |
1032 | which_clock); |
1033 | } |
1034 | |
1035 | SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, |
1036 | const struct timespec __user *, rqtp, |
1037 | struct timespec __user *, rmtp) |
1038 | { |
1039 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1040 | struct timespec t; |
1041 | |
1042 | if (!kc) |
1043 | return -EINVAL; |
1044 | if (!kc->nsleep) |
1045 | return -ENANOSLEEP_NOTSUP; |
1046 | |
1047 | if (copy_from_user(&t, rqtp, sizeof (struct timespec))) |
1048 | return -EFAULT; |
1049 | |
1050 | if (!timespec_valid(&t)) |
1051 | return -EINVAL; |
1052 | |
1053 | return kc->nsleep(which_clock, flags, &t, rmtp); |
1054 | } |
1055 | |
1056 | /* |
1057 | * This will restart clock_nanosleep. This is required only by |
1058 | * compat_clock_nanosleep_restart for now. |
1059 | */ |
1060 | long clock_nanosleep_restart(struct restart_block *restart_block) |
1061 | { |
1062 | clockid_t which_clock = restart_block->nanosleep.clockid; |
1063 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1064 | |
1065 | if (WARN_ON_ONCE(!kc || !kc->nsleep_restart)) |
1066 | return -EINVAL; |
1067 | |
1068 | return kc->nsleep_restart(restart_block); |
1069 | } |
1070 |
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