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