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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/hash.h> |
44 | #include <linux/posix-clock.h> |
45 | #include <linux/posix-timers.h> |
46 | #include <linux/syscalls.h> |
47 | #include <linux/wait.h> |
48 | #include <linux/workqueue.h> |
49 | #include <linux/export.h> |
50 | #include <linux/hashtable.h> |
51 | |
52 | /* |
53 | * Management arrays for POSIX timers. Timers are now kept in static hash table |
54 | * with 512 entries. |
55 | * Timer ids are allocated by local routine, which selects proper hash head by |
56 | * key, constructed from current->signal address and per signal struct counter. |
57 | * This keeps timer ids unique per process, but now they can intersect between |
58 | * processes. |
59 | */ |
60 | |
61 | /* |
62 | * Lets keep our timers in a slab cache :-) |
63 | */ |
64 | static struct kmem_cache *posix_timers_cache; |
65 | |
66 | static DEFINE_HASHTABLE(posix_timers_hashtable, 9); |
67 | static DEFINE_SPINLOCK(hash_lock); |
68 | |
69 | /* |
70 | * we assume that the new SIGEV_THREAD_ID shares no bits with the other |
71 | * SIGEV values. Here we put out an error if this assumption fails. |
72 | */ |
73 | #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \ |
74 | ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD)) |
75 | #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!" |
76 | #endif |
77 | |
78 | /* |
79 | * parisc wants ENOTSUP instead of EOPNOTSUPP |
80 | */ |
81 | #ifndef ENOTSUP |
82 | # define ENANOSLEEP_NOTSUP EOPNOTSUPP |
83 | #else |
84 | # define ENANOSLEEP_NOTSUP ENOTSUP |
85 | #endif |
86 | |
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 | */ |
95 | |
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. |
100 | * |
101 | * RESOLUTION: Clock resolution is used to round up timer and interval |
102 | * times, NOT to report clock times, which are reported with as |
103 | * much resolution as the system can muster. In some cases this |
104 | * resolution may depend on the underlying clock hardware and |
105 | * may not be quantifiable until run time, and only then is the |
106 | * necessary code is written. The standard says we should say |
107 | * something about this issue in the documentation... |
108 | * |
109 | * FUNCTIONS: The CLOCKs structure defines possible functions to |
110 | * handle various clock functions. |
111 | * |
112 | * The standard POSIX timer management code assumes the |
113 | * following: 1.) The k_itimer struct (sched.h) is used for |
114 | * the timer. 2.) The list, it_lock, it_clock, it_id and |
115 | * it_pid fields are not modified by timer code. |
116 | * |
117 | * Permissions: It is assumed that the clock_settime() function defined |
118 | * for each clock will take care of permission checks. Some |
119 | * clocks may be set able by any user (i.e. local process |
120 | * clocks) others not. Currently the only set able clock we |
121 | * have is CLOCK_REALTIME and its high res counter part, both of |
122 | * which we beg off on and pass to do_sys_settimeofday(). |
123 | */ |
124 | |
125 | static struct k_clock posix_clocks[MAX_CLOCKS]; |
126 | |
127 | /* |
128 | * These ones are defined below. |
129 | */ |
130 | static int common_nsleep(const clockid_t, int flags, struct timespec *t, |
131 | struct timespec __user *rmtp); |
132 | static int common_timer_create(struct k_itimer *new_timer); |
133 | static void common_timer_get(struct k_itimer *, struct itimerspec *); |
134 | static int common_timer_set(struct k_itimer *, int, |
135 | struct itimerspec *, struct itimerspec *); |
136 | static int common_timer_del(struct k_itimer *timer); |
137 | |
138 | static enum hrtimer_restart posix_timer_fn(struct hrtimer *data); |
139 | |
140 | static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags); |
141 | |
142 | #define lock_timer(tid, flags) \ |
143 | ({ struct k_itimer *__timr; \ |
144 | __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags)); \ |
145 | __timr; \ |
146 | }) |
147 | |
148 | static int hash(struct signal_struct *sig, unsigned int nr) |
149 | { |
150 | return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable)); |
151 | } |
152 | |
153 | static struct k_itimer *__posix_timers_find(struct hlist_head *head, |
154 | struct signal_struct *sig, |
155 | timer_t id) |
156 | { |
157 | struct k_itimer *timer; |
158 | |
159 | hlist_for_each_entry_rcu(timer, head, t_hash) { |
160 | if ((timer->it_signal == sig) && (timer->it_id == id)) |
161 | return timer; |
162 | } |
163 | return NULL; |
164 | } |
165 | |
166 | static struct k_itimer *posix_timer_by_id(timer_t id) |
167 | { |
168 | struct signal_struct *sig = current->signal; |
169 | struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)]; |
170 | |
171 | return __posix_timers_find(head, sig, id); |
172 | } |
173 | |
174 | static int posix_timer_add(struct k_itimer *timer) |
175 | { |
176 | struct signal_struct *sig = current->signal; |
177 | int first_free_id = sig->posix_timer_id; |
178 | struct hlist_head *head; |
179 | int ret = -ENOENT; |
180 | |
181 | do { |
182 | spin_lock(&hash_lock); |
183 | head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)]; |
184 | if (!__posix_timers_find(head, sig, sig->posix_timer_id)) { |
185 | hlist_add_head_rcu(&timer->t_hash, head); |
186 | ret = sig->posix_timer_id; |
187 | } |
188 | if (++sig->posix_timer_id < 0) |
189 | sig->posix_timer_id = 0; |
190 | if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT)) |
191 | /* Loop over all possible ids completed */ |
192 | ret = -EAGAIN; |
193 | spin_unlock(&hash_lock); |
194 | } while (ret == -ENOENT); |
195 | return ret; |
196 | } |
197 | |
198 | static inline void unlock_timer(struct k_itimer *timr, unsigned long flags) |
199 | { |
200 | spin_unlock_irqrestore(&timr->it_lock, flags); |
201 | } |
202 | |
203 | /* Get clock_realtime */ |
204 | static int posix_clock_realtime_get(clockid_t which_clock, struct timespec *tp) |
205 | { |
206 | ktime_get_real_ts(tp); |
207 | return 0; |
208 | } |
209 | |
210 | /* Set clock_realtime */ |
211 | static int posix_clock_realtime_set(const clockid_t which_clock, |
212 | const struct timespec *tp) |
213 | { |
214 | return do_sys_settimeofday(tp, NULL); |
215 | } |
216 | |
217 | static int posix_clock_realtime_adj(const clockid_t which_clock, |
218 | struct timex *t) |
219 | { |
220 | return do_adjtimex(t); |
221 | } |
222 | |
223 | /* |
224 | * Get monotonic time for posix timers |
225 | */ |
226 | static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp) |
227 | { |
228 | ktime_get_ts(tp); |
229 | return 0; |
230 | } |
231 | |
232 | /* |
233 | * Get monotonic-raw time for posix timers |
234 | */ |
235 | static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp) |
236 | { |
237 | getrawmonotonic(tp); |
238 | return 0; |
239 | } |
240 | |
241 | |
242 | static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp) |
243 | { |
244 | *tp = current_kernel_time(); |
245 | return 0; |
246 | } |
247 | |
248 | static int posix_get_monotonic_coarse(clockid_t which_clock, |
249 | struct timespec *tp) |
250 | { |
251 | *tp = get_monotonic_coarse(); |
252 | return 0; |
253 | } |
254 | |
255 | static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp) |
256 | { |
257 | *tp = ktime_to_timespec(KTIME_LOW_RES); |
258 | return 0; |
259 | } |
260 | |
261 | static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp) |
262 | { |
263 | get_monotonic_boottime(tp); |
264 | return 0; |
265 | } |
266 | |
267 | static int posix_get_tai(clockid_t which_clock, struct timespec *tp) |
268 | { |
269 | timekeeping_clocktai(tp); |
270 | return 0; |
271 | } |
272 | |
273 | /* |
274 | * Initialize everything, well, just everything in Posix clocks/timers ;) |
275 | */ |
276 | static __init int init_posix_timers(void) |
277 | { |
278 | struct k_clock clock_realtime = { |
279 | .clock_getres = hrtimer_get_res, |
280 | .clock_get = posix_clock_realtime_get, |
281 | .clock_set = posix_clock_realtime_set, |
282 | .clock_adj = posix_clock_realtime_adj, |
283 | .nsleep = common_nsleep, |
284 | .nsleep_restart = hrtimer_nanosleep_restart, |
285 | .timer_create = common_timer_create, |
286 | .timer_set = common_timer_set, |
287 | .timer_get = common_timer_get, |
288 | .timer_del = common_timer_del, |
289 | }; |
290 | struct k_clock clock_monotonic = { |
291 | .clock_getres = hrtimer_get_res, |
292 | .clock_get = posix_ktime_get_ts, |
293 | .nsleep = common_nsleep, |
294 | .nsleep_restart = hrtimer_nanosleep_restart, |
295 | .timer_create = common_timer_create, |
296 | .timer_set = common_timer_set, |
297 | .timer_get = common_timer_get, |
298 | .timer_del = common_timer_del, |
299 | }; |
300 | struct k_clock clock_monotonic_raw = { |
301 | .clock_getres = hrtimer_get_res, |
302 | .clock_get = posix_get_monotonic_raw, |
303 | }; |
304 | struct k_clock clock_realtime_coarse = { |
305 | .clock_getres = posix_get_coarse_res, |
306 | .clock_get = posix_get_realtime_coarse, |
307 | }; |
308 | struct k_clock clock_monotonic_coarse = { |
309 | .clock_getres = posix_get_coarse_res, |
310 | .clock_get = posix_get_monotonic_coarse, |
311 | }; |
312 | struct k_clock clock_tai = { |
313 | .clock_getres = hrtimer_get_res, |
314 | .clock_get = posix_get_tai, |
315 | .nsleep = common_nsleep, |
316 | .nsleep_restart = hrtimer_nanosleep_restart, |
317 | .timer_create = common_timer_create, |
318 | .timer_set = common_timer_set, |
319 | .timer_get = common_timer_get, |
320 | .timer_del = common_timer_del, |
321 | }; |
322 | struct k_clock clock_boottime = { |
323 | .clock_getres = hrtimer_get_res, |
324 | .clock_get = posix_get_boottime, |
325 | .nsleep = common_nsleep, |
326 | .nsleep_restart = hrtimer_nanosleep_restart, |
327 | .timer_create = common_timer_create, |
328 | .timer_set = common_timer_set, |
329 | .timer_get = common_timer_get, |
330 | .timer_del = common_timer_del, |
331 | }; |
332 | |
333 | posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime); |
334 | posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic); |
335 | posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw); |
336 | posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse); |
337 | posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse); |
338 | posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime); |
339 | posix_timers_register_clock(CLOCK_TAI, &clock_tai); |
340 | |
341 | posix_timers_cache = kmem_cache_create("posix_timers_cache", |
342 | sizeof (struct k_itimer), 0, SLAB_PANIC, |
343 | NULL); |
344 | return 0; |
345 | } |
346 | |
347 | __initcall(init_posix_timers); |
348 | |
349 | static void schedule_next_timer(struct k_itimer *timr) |
350 | { |
351 | struct hrtimer *timer = &timr->it.real.timer; |
352 | |
353 | if (timr->it.real.interval.tv64 == 0) |
354 | return; |
355 | |
356 | timr->it_overrun += (unsigned int) hrtimer_forward(timer, |
357 | timer->base->get_time(), |
358 | timr->it.real.interval); |
359 | |
360 | timr->it_overrun_last = timr->it_overrun; |
361 | timr->it_overrun = -1; |
362 | ++timr->it_requeue_pending; |
363 | hrtimer_restart(timer); |
364 | } |
365 | |
366 | /* |
367 | * This function is exported for use by the signal deliver code. It is |
368 | * called just prior to the info block being released and passes that |
369 | * block to us. It's function is to update the overrun entry AND to |
370 | * restart the timer. It should only be called if the timer is to be |
371 | * restarted (i.e. we have flagged this in the sys_private entry of the |
372 | * info block). |
373 | * |
374 | * To protect against the timer going away while the interrupt is queued, |
375 | * we require that the it_requeue_pending flag be set. |
376 | */ |
377 | void do_schedule_next_timer(struct siginfo *info) |
378 | { |
379 | struct k_itimer *timr; |
380 | unsigned long flags; |
381 | |
382 | timr = lock_timer(info->si_tid, &flags); |
383 | |
384 | if (timr && timr->it_requeue_pending == info->si_sys_private) { |
385 | if (timr->it_clock < 0) |
386 | posix_cpu_timer_schedule(timr); |
387 | else |
388 | schedule_next_timer(timr); |
389 | |
390 | info->si_overrun += timr->it_overrun_last; |
391 | } |
392 | |
393 | if (timr) |
394 | unlock_timer(timr, flags); |
395 | } |
396 | |
397 | int posix_timer_event(struct k_itimer *timr, int si_private) |
398 | { |
399 | struct task_struct *task; |
400 | int shared, ret = -1; |
401 | /* |
402 | * FIXME: if ->sigq is queued we can race with |
403 | * dequeue_signal()->do_schedule_next_timer(). |
404 | * |
405 | * If dequeue_signal() sees the "right" value of |
406 | * si_sys_private it calls do_schedule_next_timer(). |
407 | * We re-queue ->sigq and drop ->it_lock(). |
408 | * do_schedule_next_timer() locks the timer |
409 | * and re-schedules it while ->sigq is pending. |
410 | * Not really bad, but not that we want. |
411 | */ |
412 | timr->sigq->info.si_sys_private = si_private; |
413 | |
414 | rcu_read_lock(); |
415 | task = pid_task(timr->it_pid, PIDTYPE_PID); |
416 | if (task) { |
417 | shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); |
418 | ret = send_sigqueue(timr->sigq, task, shared); |
419 | } |
420 | rcu_read_unlock(); |
421 | /* If we failed to send the signal the timer stops. */ |
422 | return ret > 0; |
423 | } |
424 | EXPORT_SYMBOL_GPL(posix_timer_event); |
425 | |
426 | /* |
427 | * This function gets called when a POSIX.1b interval timer expires. It |
428 | * is used as a callback from the kernel internal timer. The |
429 | * run_timer_list code ALWAYS calls with interrupts on. |
430 | |
431 | * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers. |
432 | */ |
433 | static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer) |
434 | { |
435 | struct k_itimer *timr; |
436 | unsigned long flags; |
437 | int si_private = 0; |
438 | enum hrtimer_restart ret = HRTIMER_NORESTART; |
439 | |
440 | timr = container_of(timer, struct k_itimer, it.real.timer); |
441 | spin_lock_irqsave(&timr->it_lock, flags); |
442 | |
443 | if (timr->it.real.interval.tv64 != 0) |
444 | si_private = ++timr->it_requeue_pending; |
445 | |
446 | if (posix_timer_event(timr, si_private)) { |
447 | /* |
448 | * signal was not sent because of sig_ignor |
449 | * we will not get a call back to restart it AND |
450 | * it should be restarted. |
451 | */ |
452 | if (timr->it.real.interval.tv64 != 0) { |
453 | ktime_t now = hrtimer_cb_get_time(timer); |
454 | |
455 | /* |
456 | * FIXME: What we really want, is to stop this |
457 | * timer completely and restart it in case the |
458 | * SIG_IGN is removed. This is a non trivial |
459 | * change which involves sighand locking |
460 | * (sigh !), which we don't want to do late in |
461 | * the release cycle. |
462 | * |
463 | * For now we just let timers with an interval |
464 | * less than a jiffie expire every jiffie to |
465 | * avoid softirq starvation in case of SIG_IGN |
466 | * and a very small interval, which would put |
467 | * the timer right back on the softirq pending |
468 | * list. By moving now ahead of time we trick |
469 | * hrtimer_forward() to expire the timer |
470 | * later, while we still maintain the overrun |
471 | * accuracy, but have some inconsistency in |
472 | * the timer_gettime() case. This is at least |
473 | * better than a starved softirq. A more |
474 | * complex fix which solves also another related |
475 | * inconsistency is already in the pipeline. |
476 | */ |
477 | #ifdef CONFIG_HIGH_RES_TIMERS |
478 | { |
479 | ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ); |
480 | |
481 | if (timr->it.real.interval.tv64 < kj.tv64) |
482 | now = ktime_add(now, kj); |
483 | } |
484 | #endif |
485 | timr->it_overrun += (unsigned int) |
486 | hrtimer_forward(timer, now, |
487 | timr->it.real.interval); |
488 | ret = HRTIMER_RESTART; |
489 | ++timr->it_requeue_pending; |
490 | } |
491 | } |
492 | |
493 | unlock_timer(timr, flags); |
494 | return ret; |
495 | } |
496 | |
497 | static struct pid *good_sigevent(sigevent_t * event) |
498 | { |
499 | struct task_struct *rtn = current->group_leader; |
500 | |
501 | if ((event->sigev_notify & SIGEV_THREAD_ID ) && |
502 | (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) || |
503 | !same_thread_group(rtn, current) || |
504 | (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) |
505 | return NULL; |
506 | |
507 | if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) && |
508 | ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX))) |
509 | return NULL; |
510 | |
511 | return task_pid(rtn); |
512 | } |
513 | |
514 | void posix_timers_register_clock(const clockid_t clock_id, |
515 | struct k_clock *new_clock) |
516 | { |
517 | if ((unsigned) clock_id >= MAX_CLOCKS) { |
518 | printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n", |
519 | clock_id); |
520 | return; |
521 | } |
522 | |
523 | if (!new_clock->clock_get) { |
524 | printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n", |
525 | clock_id); |
526 | return; |
527 | } |
528 | if (!new_clock->clock_getres) { |
529 | printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n", |
530 | clock_id); |
531 | return; |
532 | } |
533 | |
534 | posix_clocks[clock_id] = *new_clock; |
535 | } |
536 | EXPORT_SYMBOL_GPL(posix_timers_register_clock); |
537 | |
538 | static struct k_itimer * alloc_posix_timer(void) |
539 | { |
540 | struct k_itimer *tmr; |
541 | tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL); |
542 | if (!tmr) |
543 | return tmr; |
544 | if (unlikely(!(tmr->sigq = sigqueue_alloc()))) { |
545 | kmem_cache_free(posix_timers_cache, tmr); |
546 | return NULL; |
547 | } |
548 | memset(&tmr->sigq->info, 0, sizeof(siginfo_t)); |
549 | return tmr; |
550 | } |
551 | |
552 | static void k_itimer_rcu_free(struct rcu_head *head) |
553 | { |
554 | struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu); |
555 | |
556 | kmem_cache_free(posix_timers_cache, tmr); |
557 | } |
558 | |
559 | #define IT_ID_SET 1 |
560 | #define IT_ID_NOT_SET 0 |
561 | static void release_posix_timer(struct k_itimer *tmr, int it_id_set) |
562 | { |
563 | if (it_id_set) { |
564 | unsigned long flags; |
565 | spin_lock_irqsave(&hash_lock, flags); |
566 | hlist_del_rcu(&tmr->t_hash); |
567 | spin_unlock_irqrestore(&hash_lock, flags); |
568 | } |
569 | put_pid(tmr->it_pid); |
570 | sigqueue_free(tmr->sigq); |
571 | call_rcu(&tmr->it.rcu, k_itimer_rcu_free); |
572 | } |
573 | |
574 | static struct k_clock *clockid_to_kclock(const clockid_t id) |
575 | { |
576 | if (id < 0) |
577 | return (id & CLOCKFD_MASK) == CLOCKFD ? |
578 | &clock_posix_dynamic : &clock_posix_cpu; |
579 | |
580 | if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres) |
581 | return NULL; |
582 | return &posix_clocks[id]; |
583 | } |
584 | |
585 | static int common_timer_create(struct k_itimer *new_timer) |
586 | { |
587 | hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0); |
588 | return 0; |
589 | } |
590 | |
591 | /* Create a POSIX.1b interval timer. */ |
592 | |
593 | SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, |
594 | struct sigevent __user *, timer_event_spec, |
595 | timer_t __user *, created_timer_id) |
596 | { |
597 | struct k_clock *kc = clockid_to_kclock(which_clock); |
598 | struct k_itimer *new_timer; |
599 | int error, new_timer_id; |
600 | sigevent_t event; |
601 | int it_id_set = IT_ID_NOT_SET; |
602 | |
603 | if (!kc) |
604 | return -EINVAL; |
605 | if (!kc->timer_create) |
606 | return -EOPNOTSUPP; |
607 | |
608 | new_timer = alloc_posix_timer(); |
609 | if (unlikely(!new_timer)) |
610 | return -EAGAIN; |
611 | |
612 | spin_lock_init(&new_timer->it_lock); |
613 | new_timer_id = posix_timer_add(new_timer); |
614 | if (new_timer_id < 0) { |
615 | error = new_timer_id; |
616 | goto out; |
617 | } |
618 | |
619 | it_id_set = IT_ID_SET; |
620 | new_timer->it_id = (timer_t) new_timer_id; |
621 | new_timer->it_clock = which_clock; |
622 | new_timer->it_overrun = -1; |
623 | |
624 | if (timer_event_spec) { |
625 | if (copy_from_user(&event, timer_event_spec, sizeof (event))) { |
626 | error = -EFAULT; |
627 | goto out; |
628 | } |
629 | rcu_read_lock(); |
630 | new_timer->it_pid = get_pid(good_sigevent(&event)); |
631 | rcu_read_unlock(); |
632 | if (!new_timer->it_pid) { |
633 | error = -EINVAL; |
634 | goto out; |
635 | } |
636 | } else { |
637 | event.sigev_notify = SIGEV_SIGNAL; |
638 | event.sigev_signo = SIGALRM; |
639 | event.sigev_value.sival_int = new_timer->it_id; |
640 | new_timer->it_pid = get_pid(task_tgid(current)); |
641 | } |
642 | |
643 | new_timer->it_sigev_notify = event.sigev_notify; |
644 | new_timer->sigq->info.si_signo = event.sigev_signo; |
645 | new_timer->sigq->info.si_value = event.sigev_value; |
646 | new_timer->sigq->info.si_tid = new_timer->it_id; |
647 | new_timer->sigq->info.si_code = SI_TIMER; |
648 | |
649 | if (copy_to_user(created_timer_id, |
650 | &new_timer_id, sizeof (new_timer_id))) { |
651 | error = -EFAULT; |
652 | goto out; |
653 | } |
654 | |
655 | error = kc->timer_create(new_timer); |
656 | if (error) |
657 | goto out; |
658 | |
659 | spin_lock_irq(¤t->sighand->siglock); |
660 | new_timer->it_signal = current->signal; |
661 | list_add(&new_timer->list, ¤t->signal->posix_timers); |
662 | spin_unlock_irq(¤t->sighand->siglock); |
663 | |
664 | return 0; |
665 | /* |
666 | * In the case of the timer belonging to another task, after |
667 | * the task is unlocked, the timer is owned by the other task |
668 | * and may cease to exist at any time. Don't use or modify |
669 | * new_timer after the unlock call. |
670 | */ |
671 | out: |
672 | release_posix_timer(new_timer, it_id_set); |
673 | return error; |
674 | } |
675 | |
676 | /* |
677 | * Locking issues: We need to protect the result of the id look up until |
678 | * we get the timer locked down so it is not deleted under us. The |
679 | * removal is done under the idr spinlock so we use that here to bridge |
680 | * the find to the timer lock. To avoid a dead lock, the timer id MUST |
681 | * be release with out holding the timer lock. |
682 | */ |
683 | static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) |
684 | { |
685 | struct k_itimer *timr; |
686 | |
687 | /* |
688 | * timer_t could be any type >= int and we want to make sure any |
689 | * @timer_id outside positive int range fails lookup. |
690 | */ |
691 | if ((unsigned long long)timer_id > INT_MAX) |
692 | return NULL; |
693 | |
694 | rcu_read_lock(); |
695 | timr = posix_timer_by_id(timer_id); |
696 | if (timr) { |
697 | spin_lock_irqsave(&timr->it_lock, *flags); |
698 | if (timr->it_signal == current->signal) { |
699 | rcu_read_unlock(); |
700 | return timr; |
701 | } |
702 | spin_unlock_irqrestore(&timr->it_lock, *flags); |
703 | } |
704 | rcu_read_unlock(); |
705 | |
706 | return NULL; |
707 | } |
708 | |
709 | /* |
710 | * Get the time remaining on a POSIX.1b interval timer. This function |
711 | * is ALWAYS called with spin_lock_irq on the timer, thus it must not |
712 | * mess with irq. |
713 | * |
714 | * We have a couple of messes to clean up here. First there is the case |
715 | * of a timer that has a requeue pending. These timers should appear to |
716 | * be in the timer list with an expiry as if we were to requeue them |
717 | * now. |
718 | * |
719 | * The second issue is the SIGEV_NONE timer which may be active but is |
720 | * not really ever put in the timer list (to save system resources). |
721 | * This timer may be expired, and if so, we will do it here. Otherwise |
722 | * it is the same as a requeue pending timer WRT to what we should |
723 | * report. |
724 | */ |
725 | static void |
726 | common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) |
727 | { |
728 | ktime_t now, remaining, iv; |
729 | struct hrtimer *timer = &timr->it.real.timer; |
730 | |
731 | memset(cur_setting, 0, sizeof(struct itimerspec)); |
732 | |
733 | iv = timr->it.real.interval; |
734 | |
735 | /* interval timer ? */ |
736 | if (iv.tv64) |
737 | cur_setting->it_interval = ktime_to_timespec(iv); |
738 | else if (!hrtimer_active(timer) && |
739 | (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) |
740 | return; |
741 | |
742 | now = timer->base->get_time(); |
743 | |
744 | /* |
745 | * When a requeue is pending or this is a SIGEV_NONE |
746 | * timer move the expiry time forward by intervals, so |
747 | * expiry is > now. |
748 | */ |
749 | if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || |
750 | (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) |
751 | timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); |
752 | |
753 | remaining = ktime_sub(hrtimer_get_expires(timer), now); |
754 | /* Return 0 only, when the timer is expired and not pending */ |
755 | if (remaining.tv64 <= 0) { |
756 | /* |
757 | * A single shot SIGEV_NONE timer must return 0, when |
758 | * it is expired ! |
759 | */ |
760 | if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) |
761 | cur_setting->it_value.tv_nsec = 1; |
762 | } else |
763 | cur_setting->it_value = ktime_to_timespec(remaining); |
764 | } |
765 | |
766 | /* Get the time remaining on a POSIX.1b interval timer. */ |
767 | SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id, |
768 | struct itimerspec __user *, setting) |
769 | { |
770 | struct itimerspec cur_setting; |
771 | struct k_itimer *timr; |
772 | struct k_clock *kc; |
773 | unsigned long flags; |
774 | int ret = 0; |
775 | |
776 | timr = lock_timer(timer_id, &flags); |
777 | if (!timr) |
778 | return -EINVAL; |
779 | |
780 | kc = clockid_to_kclock(timr->it_clock); |
781 | if (WARN_ON_ONCE(!kc || !kc->timer_get)) |
782 | ret = -EINVAL; |
783 | else |
784 | kc->timer_get(timr, &cur_setting); |
785 | |
786 | unlock_timer(timr, flags); |
787 | |
788 | if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting))) |
789 | return -EFAULT; |
790 | |
791 | return ret; |
792 | } |
793 | |
794 | /* |
795 | * Get the number of overruns of a POSIX.1b interval timer. This is to |
796 | * be the overrun of the timer last delivered. At the same time we are |
797 | * accumulating overruns on the next timer. The overrun is frozen when |
798 | * the signal is delivered, either at the notify time (if the info block |
799 | * is not queued) or at the actual delivery time (as we are informed by |
800 | * the call back to do_schedule_next_timer(). So all we need to do is |
801 | * to pick up the frozen overrun. |
802 | */ |
803 | SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) |
804 | { |
805 | struct k_itimer *timr; |
806 | int overrun; |
807 | unsigned long flags; |
808 | |
809 | timr = lock_timer(timer_id, &flags); |
810 | if (!timr) |
811 | return -EINVAL; |
812 | |
813 | overrun = timr->it_overrun_last; |
814 | unlock_timer(timr, flags); |
815 | |
816 | return overrun; |
817 | } |
818 | |
819 | /* Set a POSIX.1b interval timer. */ |
820 | /* timr->it_lock is taken. */ |
821 | static int |
822 | common_timer_set(struct k_itimer *timr, int flags, |
823 | struct itimerspec *new_setting, struct itimerspec *old_setting) |
824 | { |
825 | struct hrtimer *timer = &timr->it.real.timer; |
826 | enum hrtimer_mode mode; |
827 | |
828 | if (old_setting) |
829 | common_timer_get(timr, old_setting); |
830 | |
831 | /* disable the timer */ |
832 | timr->it.real.interval.tv64 = 0; |
833 | /* |
834 | * careful here. If smp we could be in the "fire" routine which will |
835 | * be spinning as we hold the lock. But this is ONLY an SMP issue. |
836 | */ |
837 | if (hrtimer_try_to_cancel(timer) < 0) |
838 | return TIMER_RETRY; |
839 | |
840 | timr->it_requeue_pending = (timr->it_requeue_pending + 2) & |
841 | ~REQUEUE_PENDING; |
842 | timr->it_overrun_last = 0; |
843 | |
844 | /* switch off the timer when it_value is zero */ |
845 | if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) |
846 | return 0; |
847 | |
848 | mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; |
849 | hrtimer_init(&timr->it.real.timer, timr->it_clock, mode); |
850 | timr->it.real.timer.function = posix_timer_fn; |
851 | |
852 | hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value)); |
853 | |
854 | /* Convert interval */ |
855 | timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); |
856 | |
857 | /* SIGEV_NONE timers are not queued ! See common_timer_get */ |
858 | if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { |
859 | /* Setup correct expiry time for relative timers */ |
860 | if (mode == HRTIMER_MODE_REL) { |
861 | hrtimer_add_expires(timer, timer->base->get_time()); |
862 | } |
863 | return 0; |
864 | } |
865 | |
866 | hrtimer_start_expires(timer, mode); |
867 | return 0; |
868 | } |
869 | |
870 | /* Set a POSIX.1b interval timer */ |
871 | SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, |
872 | const struct itimerspec __user *, new_setting, |
873 | struct itimerspec __user *, old_setting) |
874 | { |
875 | struct k_itimer *timr; |
876 | struct itimerspec new_spec, old_spec; |
877 | int error = 0; |
878 | unsigned long flag; |
879 | struct itimerspec *rtn = old_setting ? &old_spec : NULL; |
880 | struct k_clock *kc; |
881 | |
882 | if (!new_setting) |
883 | return -EINVAL; |
884 | |
885 | if (copy_from_user(&new_spec, new_setting, sizeof (new_spec))) |
886 | return -EFAULT; |
887 | |
888 | if (!timespec_valid(&new_spec.it_interval) || |
889 | !timespec_valid(&new_spec.it_value)) |
890 | return -EINVAL; |
891 | retry: |
892 | timr = lock_timer(timer_id, &flag); |
893 | if (!timr) |
894 | return -EINVAL; |
895 | |
896 | kc = clockid_to_kclock(timr->it_clock); |
897 | if (WARN_ON_ONCE(!kc || !kc->timer_set)) |
898 | error = -EINVAL; |
899 | else |
900 | error = kc->timer_set(timr, flags, &new_spec, rtn); |
901 | |
902 | unlock_timer(timr, flag); |
903 | if (error == TIMER_RETRY) { |
904 | rtn = NULL; // We already got the old time... |
905 | goto retry; |
906 | } |
907 | |
908 | if (old_setting && !error && |
909 | copy_to_user(old_setting, &old_spec, sizeof (old_spec))) |
910 | error = -EFAULT; |
911 | |
912 | return error; |
913 | } |
914 | |
915 | static int common_timer_del(struct k_itimer *timer) |
916 | { |
917 | timer->it.real.interval.tv64 = 0; |
918 | |
919 | if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0) |
920 | return TIMER_RETRY; |
921 | return 0; |
922 | } |
923 | |
924 | static inline int timer_delete_hook(struct k_itimer *timer) |
925 | { |
926 | struct k_clock *kc = clockid_to_kclock(timer->it_clock); |
927 | |
928 | if (WARN_ON_ONCE(!kc || !kc->timer_del)) |
929 | return -EINVAL; |
930 | return kc->timer_del(timer); |
931 | } |
932 | |
933 | /* Delete a POSIX.1b interval timer. */ |
934 | SYSCALL_DEFINE1(timer_delete, timer_t, timer_id) |
935 | { |
936 | struct k_itimer *timer; |
937 | unsigned long flags; |
938 | |
939 | retry_delete: |
940 | timer = lock_timer(timer_id, &flags); |
941 | if (!timer) |
942 | return -EINVAL; |
943 | |
944 | if (timer_delete_hook(timer) == TIMER_RETRY) { |
945 | unlock_timer(timer, flags); |
946 | goto retry_delete; |
947 | } |
948 | |
949 | spin_lock(¤t->sighand->siglock); |
950 | list_del(&timer->list); |
951 | spin_unlock(¤t->sighand->siglock); |
952 | /* |
953 | * This keeps any tasks waiting on the spin lock from thinking |
954 | * they got something (see the lock code above). |
955 | */ |
956 | timer->it_signal = NULL; |
957 | |
958 | unlock_timer(timer, flags); |
959 | release_posix_timer(timer, IT_ID_SET); |
960 | return 0; |
961 | } |
962 | |
963 | /* |
964 | * return timer owned by the process, used by exit_itimers |
965 | */ |
966 | static void itimer_delete(struct k_itimer *timer) |
967 | { |
968 | unsigned long flags; |
969 | |
970 | retry_delete: |
971 | spin_lock_irqsave(&timer->it_lock, flags); |
972 | |
973 | if (timer_delete_hook(timer) == TIMER_RETRY) { |
974 | unlock_timer(timer, flags); |
975 | goto retry_delete; |
976 | } |
977 | list_del(&timer->list); |
978 | /* |
979 | * This keeps any tasks waiting on the spin lock from thinking |
980 | * they got something (see the lock code above). |
981 | */ |
982 | timer->it_signal = NULL; |
983 | |
984 | unlock_timer(timer, flags); |
985 | release_posix_timer(timer, IT_ID_SET); |
986 | } |
987 | |
988 | /* |
989 | * This is called by do_exit or de_thread, only when there are no more |
990 | * references to the shared signal_struct. |
991 | */ |
992 | void exit_itimers(struct signal_struct *sig) |
993 | { |
994 | struct k_itimer *tmr; |
995 | |
996 | while (!list_empty(&sig->posix_timers)) { |
997 | tmr = list_entry(sig->posix_timers.next, struct k_itimer, list); |
998 | itimer_delete(tmr); |
999 | } |
1000 | } |
1001 | |
1002 | SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, |
1003 | const struct timespec __user *, tp) |
1004 | { |
1005 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1006 | struct timespec new_tp; |
1007 | |
1008 | if (!kc || !kc->clock_set) |
1009 | return -EINVAL; |
1010 | |
1011 | if (copy_from_user(&new_tp, tp, sizeof (*tp))) |
1012 | return -EFAULT; |
1013 | |
1014 | return kc->clock_set(which_clock, &new_tp); |
1015 | } |
1016 | |
1017 | SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, |
1018 | struct timespec __user *,tp) |
1019 | { |
1020 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1021 | struct timespec kernel_tp; |
1022 | int error; |
1023 | |
1024 | if (!kc) |
1025 | return -EINVAL; |
1026 | |
1027 | error = kc->clock_get(which_clock, &kernel_tp); |
1028 | |
1029 | if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) |
1030 | error = -EFAULT; |
1031 | |
1032 | return error; |
1033 | } |
1034 | |
1035 | SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock, |
1036 | struct timex __user *, utx) |
1037 | { |
1038 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1039 | struct timex ktx; |
1040 | int err; |
1041 | |
1042 | if (!kc) |
1043 | return -EINVAL; |
1044 | if (!kc->clock_adj) |
1045 | return -EOPNOTSUPP; |
1046 | |
1047 | if (copy_from_user(&ktx, utx, sizeof(ktx))) |
1048 | return -EFAULT; |
1049 | |
1050 | err = kc->clock_adj(which_clock, &ktx); |
1051 | |
1052 | if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx))) |
1053 | return -EFAULT; |
1054 | |
1055 | return err; |
1056 | } |
1057 | |
1058 | SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, |
1059 | struct timespec __user *, tp) |
1060 | { |
1061 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1062 | struct timespec rtn_tp; |
1063 | int error; |
1064 | |
1065 | if (!kc) |
1066 | return -EINVAL; |
1067 | |
1068 | error = kc->clock_getres(which_clock, &rtn_tp); |
1069 | |
1070 | if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) |
1071 | error = -EFAULT; |
1072 | |
1073 | return error; |
1074 | } |
1075 | |
1076 | /* |
1077 | * nanosleep for monotonic and realtime clocks |
1078 | */ |
1079 | static int common_nsleep(const clockid_t which_clock, int flags, |
1080 | struct timespec *tsave, struct timespec __user *rmtp) |
1081 | { |
1082 | return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ? |
1083 | HRTIMER_MODE_ABS : HRTIMER_MODE_REL, |
1084 | which_clock); |
1085 | } |
1086 | |
1087 | SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, |
1088 | const struct timespec __user *, rqtp, |
1089 | struct timespec __user *, rmtp) |
1090 | { |
1091 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1092 | struct timespec t; |
1093 | |
1094 | if (!kc) |
1095 | return -EINVAL; |
1096 | if (!kc->nsleep) |
1097 | return -ENANOSLEEP_NOTSUP; |
1098 | |
1099 | if (copy_from_user(&t, rqtp, sizeof (struct timespec))) |
1100 | return -EFAULT; |
1101 | |
1102 | if (!timespec_valid(&t)) |
1103 | return -EINVAL; |
1104 | |
1105 | return kc->nsleep(which_clock, flags, &t, rmtp); |
1106 | } |
1107 | |
1108 | /* |
1109 | * This will restart clock_nanosleep. This is required only by |
1110 | * compat_clock_nanosleep_restart for now. |
1111 | */ |
1112 | long clock_nanosleep_restart(struct restart_block *restart_block) |
1113 | { |
1114 | clockid_t which_clock = restart_block->nanosleep.clockid; |
1115 | struct k_clock *kc = clockid_to_kclock(which_clock); |
1116 | |
1117 | if (WARN_ON_ONCE(!kc || !kc->nsleep_restart)) |
1118 | return -EINVAL; |
1119 | |
1120 | return kc->nsleep_restart(restart_block); |
1121 | } |
1122 |
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