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c0a31329 TG |
1 | /* |
2 | * linux/kernel/hrtimer.c | |
3 | * | |
4 | * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> | |
5 | * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar | |
6 | * | |
7 | * High-resolution kernel timers | |
8 | * | |
9 | * In contrast to the low-resolution timeout API implemented in | |
10 | * kernel/timer.c, hrtimers provide finer resolution and accuracy | |
11 | * depending on system configuration and capabilities. | |
12 | * | |
13 | * These timers are currently used for: | |
14 | * - itimers | |
15 | * - POSIX timers | |
16 | * - nanosleep | |
17 | * - precise in-kernel timing | |
18 | * | |
19 | * Started by: Thomas Gleixner and Ingo Molnar | |
20 | * | |
21 | * Credits: | |
22 | * based on kernel/timer.c | |
23 | * | |
24 | * For licencing details see kernel-base/COPYING | |
25 | */ | |
26 | ||
27 | #include <linux/cpu.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/percpu.h> | |
30 | #include <linux/hrtimer.h> | |
31 | #include <linux/notifier.h> | |
32 | #include <linux/syscalls.h> | |
33 | #include <linux/interrupt.h> | |
34 | ||
35 | #include <asm/uaccess.h> | |
36 | ||
37 | /** | |
38 | * ktime_get - get the monotonic time in ktime_t format | |
39 | * | |
40 | * returns the time in ktime_t format | |
41 | */ | |
42 | static ktime_t ktime_get(void) | |
43 | { | |
44 | struct timespec now; | |
45 | ||
46 | ktime_get_ts(&now); | |
47 | ||
48 | return timespec_to_ktime(now); | |
49 | } | |
50 | ||
51 | /** | |
52 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
53 | * | |
54 | * returns the time in ktime_t format | |
55 | */ | |
56 | static ktime_t ktime_get_real(void) | |
57 | { | |
58 | struct timespec now; | |
59 | ||
60 | getnstimeofday(&now); | |
61 | ||
62 | return timespec_to_ktime(now); | |
63 | } | |
64 | ||
65 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
66 | ||
67 | /* | |
68 | * The timer bases: | |
69 | */ | |
70 | ||
71 | #define MAX_HRTIMER_BASES 2 | |
72 | ||
73 | static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) = | |
74 | { | |
75 | { | |
76 | .index = CLOCK_REALTIME, | |
77 | .get_time = &ktime_get_real, | |
78 | .resolution = KTIME_REALTIME_RES, | |
79 | }, | |
80 | { | |
81 | .index = CLOCK_MONOTONIC, | |
82 | .get_time = &ktime_get, | |
83 | .resolution = KTIME_MONOTONIC_RES, | |
84 | }, | |
85 | }; | |
86 | ||
87 | /** | |
88 | * ktime_get_ts - get the monotonic clock in timespec format | |
89 | * | |
90 | * @ts: pointer to timespec variable | |
91 | * | |
92 | * The function calculates the monotonic clock from the realtime | |
93 | * clock and the wall_to_monotonic offset and stores the result | |
94 | * in normalized timespec format in the variable pointed to by ts. | |
95 | */ | |
96 | void ktime_get_ts(struct timespec *ts) | |
97 | { | |
98 | struct timespec tomono; | |
99 | unsigned long seq; | |
100 | ||
101 | do { | |
102 | seq = read_seqbegin(&xtime_lock); | |
103 | getnstimeofday(ts); | |
104 | tomono = wall_to_monotonic; | |
105 | ||
106 | } while (read_seqretry(&xtime_lock, seq)); | |
107 | ||
108 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
109 | ts->tv_nsec + tomono.tv_nsec); | |
110 | } | |
69778e32 | 111 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
c0a31329 TG |
112 | |
113 | /* | |
114 | * Functions and macros which are different for UP/SMP systems are kept in a | |
115 | * single place | |
116 | */ | |
117 | #ifdef CONFIG_SMP | |
118 | ||
119 | #define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0) | |
120 | ||
121 | /* | |
122 | * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock | |
123 | * means that all timers which are tied to this base via timer->base are | |
124 | * locked, and the base itself is locked too. | |
125 | * | |
126 | * So __run_timers/migrate_timers can safely modify all timers which could | |
127 | * be found on the lists/queues. | |
128 | * | |
129 | * When the timer's base is locked, and the timer removed from list, it is | |
130 | * possible to set timer->base = NULL and drop the lock: the timer remains | |
131 | * locked. | |
132 | */ | |
133 | static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer, | |
134 | unsigned long *flags) | |
135 | { | |
136 | struct hrtimer_base *base; | |
137 | ||
138 | for (;;) { | |
139 | base = timer->base; | |
140 | if (likely(base != NULL)) { | |
141 | spin_lock_irqsave(&base->lock, *flags); | |
142 | if (likely(base == timer->base)) | |
143 | return base; | |
144 | /* The timer has migrated to another CPU: */ | |
145 | spin_unlock_irqrestore(&base->lock, *flags); | |
146 | } | |
147 | cpu_relax(); | |
148 | } | |
149 | } | |
150 | ||
151 | /* | |
152 | * Switch the timer base to the current CPU when possible. | |
153 | */ | |
154 | static inline struct hrtimer_base * | |
155 | switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) | |
156 | { | |
157 | struct hrtimer_base *new_base; | |
158 | ||
159 | new_base = &__get_cpu_var(hrtimer_bases[base->index]); | |
160 | ||
161 | if (base != new_base) { | |
162 | /* | |
163 | * We are trying to schedule the timer on the local CPU. | |
164 | * However we can't change timer's base while it is running, | |
165 | * so we keep it on the same CPU. No hassle vs. reprogramming | |
166 | * the event source in the high resolution case. The softirq | |
167 | * code will take care of this when the timer function has | |
168 | * completed. There is no conflict as we hold the lock until | |
169 | * the timer is enqueued. | |
170 | */ | |
171 | if (unlikely(base->curr_timer == timer)) | |
172 | return base; | |
173 | ||
174 | /* See the comment in lock_timer_base() */ | |
175 | timer->base = NULL; | |
176 | spin_unlock(&base->lock); | |
177 | spin_lock(&new_base->lock); | |
178 | timer->base = new_base; | |
179 | } | |
180 | return new_base; | |
181 | } | |
182 | ||
183 | #else /* CONFIG_SMP */ | |
184 | ||
185 | #define set_curr_timer(b, t) do { } while (0) | |
186 | ||
187 | static inline struct hrtimer_base * | |
188 | lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
189 | { | |
190 | struct hrtimer_base *base = timer->base; | |
191 | ||
192 | spin_lock_irqsave(&base->lock, *flags); | |
193 | ||
194 | return base; | |
195 | } | |
196 | ||
197 | #define switch_hrtimer_base(t, b) (b) | |
198 | ||
199 | #endif /* !CONFIG_SMP */ | |
200 | ||
201 | /* | |
202 | * Functions for the union type storage format of ktime_t which are | |
203 | * too large for inlining: | |
204 | */ | |
205 | #if BITS_PER_LONG < 64 | |
206 | # ifndef CONFIG_KTIME_SCALAR | |
207 | /** | |
208 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable | |
209 | * | |
210 | * @kt: addend | |
211 | * @nsec: the scalar nsec value to add | |
212 | * | |
213 | * Returns the sum of kt and nsec in ktime_t format | |
214 | */ | |
215 | ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) | |
216 | { | |
217 | ktime_t tmp; | |
218 | ||
219 | if (likely(nsec < NSEC_PER_SEC)) { | |
220 | tmp.tv64 = nsec; | |
221 | } else { | |
222 | unsigned long rem = do_div(nsec, NSEC_PER_SEC); | |
223 | ||
224 | tmp = ktime_set((long)nsec, rem); | |
225 | } | |
226 | ||
227 | return ktime_add(kt, tmp); | |
228 | } | |
229 | ||
230 | #else /* CONFIG_KTIME_SCALAR */ | |
231 | ||
232 | # endif /* !CONFIG_KTIME_SCALAR */ | |
233 | ||
234 | /* | |
235 | * Divide a ktime value by a nanosecond value | |
236 | */ | |
237 | static unsigned long ktime_divns(const ktime_t kt, nsec_t div) | |
238 | { | |
239 | u64 dclc, inc, dns; | |
240 | int sft = 0; | |
241 | ||
242 | dclc = dns = ktime_to_ns(kt); | |
243 | inc = div; | |
244 | /* Make sure the divisor is less than 2^32: */ | |
245 | while (div >> 32) { | |
246 | sft++; | |
247 | div >>= 1; | |
248 | } | |
249 | dclc >>= sft; | |
250 | do_div(dclc, (unsigned long) div); | |
251 | ||
252 | return (unsigned long) dclc; | |
253 | } | |
254 | ||
255 | #else /* BITS_PER_LONG < 64 */ | |
256 | # define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) | |
257 | #endif /* BITS_PER_LONG >= 64 */ | |
258 | ||
259 | /* | |
260 | * Counterpart to lock_timer_base above: | |
261 | */ | |
262 | static inline | |
263 | void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
264 | { | |
265 | spin_unlock_irqrestore(&timer->base->lock, *flags); | |
266 | } | |
267 | ||
268 | /** | |
269 | * hrtimer_forward - forward the timer expiry | |
270 | * | |
271 | * @timer: hrtimer to forward | |
272 | * @interval: the interval to forward | |
273 | * | |
274 | * Forward the timer expiry so it will expire in the future. | |
8dca6f33 | 275 | * Returns the number of overruns. |
c0a31329 TG |
276 | */ |
277 | unsigned long | |
c9db4fa1 | 278 | hrtimer_forward(struct hrtimer *timer, ktime_t interval) |
c0a31329 TG |
279 | { |
280 | unsigned long orun = 1; | |
281 | ktime_t delta, now; | |
282 | ||
283 | now = timer->base->get_time(); | |
284 | ||
285 | delta = ktime_sub(now, timer->expires); | |
286 | ||
287 | if (delta.tv64 < 0) | |
288 | return 0; | |
289 | ||
c9db4fa1 TG |
290 | if (interval.tv64 < timer->base->resolution.tv64) |
291 | interval.tv64 = timer->base->resolution.tv64; | |
292 | ||
c0a31329 TG |
293 | if (unlikely(delta.tv64 >= interval.tv64)) { |
294 | nsec_t incr = ktime_to_ns(interval); | |
295 | ||
296 | orun = ktime_divns(delta, incr); | |
297 | timer->expires = ktime_add_ns(timer->expires, incr * orun); | |
298 | if (timer->expires.tv64 > now.tv64) | |
299 | return orun; | |
300 | /* | |
301 | * This (and the ktime_add() below) is the | |
302 | * correction for exact: | |
303 | */ | |
304 | orun++; | |
305 | } | |
306 | timer->expires = ktime_add(timer->expires, interval); | |
307 | ||
308 | return orun; | |
309 | } | |
310 | ||
311 | /* | |
312 | * enqueue_hrtimer - internal function to (re)start a timer | |
313 | * | |
314 | * The timer is inserted in expiry order. Insertion into the | |
315 | * red black tree is O(log(n)). Must hold the base lock. | |
316 | */ | |
317 | static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
318 | { | |
319 | struct rb_node **link = &base->active.rb_node; | |
c0a31329 TG |
320 | struct rb_node *parent = NULL; |
321 | struct hrtimer *entry; | |
322 | ||
323 | /* | |
324 | * Find the right place in the rbtree: | |
325 | */ | |
326 | while (*link) { | |
327 | parent = *link; | |
328 | entry = rb_entry(parent, struct hrtimer, node); | |
329 | /* | |
330 | * We dont care about collisions. Nodes with | |
331 | * the same expiry time stay together. | |
332 | */ | |
333 | if (timer->expires.tv64 < entry->expires.tv64) | |
334 | link = &(*link)->rb_left; | |
288867ec | 335 | else |
c0a31329 | 336 | link = &(*link)->rb_right; |
c0a31329 TG |
337 | } |
338 | ||
339 | /* | |
288867ec TG |
340 | * Insert the timer to the rbtree and check whether it |
341 | * replaces the first pending timer | |
c0a31329 TG |
342 | */ |
343 | rb_link_node(&timer->node, parent, link); | |
344 | rb_insert_color(&timer->node, &base->active); | |
c0a31329 TG |
345 | |
346 | timer->state = HRTIMER_PENDING; | |
c0a31329 | 347 | |
288867ec TG |
348 | if (!base->first || timer->expires.tv64 < |
349 | rb_entry(base->first, struct hrtimer, node)->expires.tv64) | |
350 | base->first = &timer->node; | |
351 | } | |
c0a31329 TG |
352 | |
353 | /* | |
354 | * __remove_hrtimer - internal function to remove a timer | |
355 | * | |
356 | * Caller must hold the base lock. | |
357 | */ | |
358 | static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
359 | { | |
360 | /* | |
288867ec TG |
361 | * Remove the timer from the rbtree and replace the |
362 | * first entry pointer if necessary. | |
c0a31329 | 363 | */ |
288867ec TG |
364 | if (base->first == &timer->node) |
365 | base->first = rb_next(&timer->node); | |
c0a31329 TG |
366 | rb_erase(&timer->node, &base->active); |
367 | } | |
368 | ||
369 | /* | |
370 | * remove hrtimer, called with base lock held | |
371 | */ | |
372 | static inline int | |
373 | remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
374 | { | |
375 | if (hrtimer_active(timer)) { | |
376 | __remove_hrtimer(timer, base); | |
377 | timer->state = HRTIMER_INACTIVE; | |
378 | return 1; | |
379 | } | |
380 | return 0; | |
381 | } | |
382 | ||
383 | /** | |
384 | * hrtimer_start - (re)start an relative timer on the current CPU | |
385 | * | |
386 | * @timer: the timer to be added | |
387 | * @tim: expiry time | |
388 | * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) | |
389 | * | |
390 | * Returns: | |
391 | * 0 on success | |
392 | * 1 when the timer was active | |
393 | */ | |
394 | int | |
395 | hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) | |
396 | { | |
397 | struct hrtimer_base *base, *new_base; | |
398 | unsigned long flags; | |
399 | int ret; | |
400 | ||
401 | base = lock_hrtimer_base(timer, &flags); | |
402 | ||
403 | /* Remove an active timer from the queue: */ | |
404 | ret = remove_hrtimer(timer, base); | |
405 | ||
406 | /* Switch the timer base, if necessary: */ | |
407 | new_base = switch_hrtimer_base(timer, base); | |
408 | ||
409 | if (mode == HRTIMER_REL) | |
410 | tim = ktime_add(tim, new_base->get_time()); | |
411 | timer->expires = tim; | |
412 | ||
413 | enqueue_hrtimer(timer, new_base); | |
414 | ||
415 | unlock_hrtimer_base(timer, &flags); | |
416 | ||
417 | return ret; | |
418 | } | |
419 | ||
420 | /** | |
421 | * hrtimer_try_to_cancel - try to deactivate a timer | |
422 | * | |
423 | * @timer: hrtimer to stop | |
424 | * | |
425 | * Returns: | |
426 | * 0 when the timer was not active | |
427 | * 1 when the timer was active | |
428 | * -1 when the timer is currently excuting the callback function and | |
429 | * can not be stopped | |
430 | */ | |
431 | int hrtimer_try_to_cancel(struct hrtimer *timer) | |
432 | { | |
433 | struct hrtimer_base *base; | |
434 | unsigned long flags; | |
435 | int ret = -1; | |
436 | ||
437 | base = lock_hrtimer_base(timer, &flags); | |
438 | ||
439 | if (base->curr_timer != timer) | |
440 | ret = remove_hrtimer(timer, base); | |
441 | ||
442 | unlock_hrtimer_base(timer, &flags); | |
443 | ||
444 | return ret; | |
445 | ||
446 | } | |
447 | ||
448 | /** | |
449 | * hrtimer_cancel - cancel a timer and wait for the handler to finish. | |
450 | * | |
451 | * @timer: the timer to be cancelled | |
452 | * | |
453 | * Returns: | |
454 | * 0 when the timer was not active | |
455 | * 1 when the timer was active | |
456 | */ | |
457 | int hrtimer_cancel(struct hrtimer *timer) | |
458 | { | |
459 | for (;;) { | |
460 | int ret = hrtimer_try_to_cancel(timer); | |
461 | ||
462 | if (ret >= 0) | |
463 | return ret; | |
464 | } | |
465 | } | |
466 | ||
467 | /** | |
468 | * hrtimer_get_remaining - get remaining time for the timer | |
469 | * | |
470 | * @timer: the timer to read | |
471 | */ | |
472 | ktime_t hrtimer_get_remaining(const struct hrtimer *timer) | |
473 | { | |
474 | struct hrtimer_base *base; | |
475 | unsigned long flags; | |
476 | ktime_t rem; | |
477 | ||
478 | base = lock_hrtimer_base(timer, &flags); | |
479 | rem = ktime_sub(timer->expires, timer->base->get_time()); | |
480 | unlock_hrtimer_base(timer, &flags); | |
481 | ||
482 | return rem; | |
483 | } | |
484 | ||
485 | /** | |
486 | * hrtimer_rebase - rebase an initialized hrtimer to a different base | |
487 | * | |
488 | * @timer: the timer to be rebased | |
489 | * @clock_id: the clock to be used | |
490 | */ | |
491 | void hrtimer_rebase(struct hrtimer *timer, const clockid_t clock_id) | |
492 | { | |
493 | struct hrtimer_base *bases; | |
494 | ||
495 | bases = per_cpu(hrtimer_bases, raw_smp_processor_id()); | |
496 | timer->base = &bases[clock_id]; | |
497 | } | |
498 | ||
499 | /** | |
500 | * hrtimer_init - initialize a timer to the given clock | |
501 | * | |
502 | * @timer: the timer to be initialized | |
503 | * @clock_id: the clock to be used | |
504 | */ | |
505 | void hrtimer_init(struct hrtimer *timer, const clockid_t clock_id) | |
506 | { | |
507 | memset(timer, 0, sizeof(struct hrtimer)); | |
508 | hrtimer_rebase(timer, clock_id); | |
509 | } | |
510 | ||
511 | /** | |
512 | * hrtimer_get_res - get the timer resolution for a clock | |
513 | * | |
514 | * @which_clock: which clock to query | |
515 | * @tp: pointer to timespec variable to store the resolution | |
516 | * | |
517 | * Store the resolution of the clock selected by which_clock in the | |
518 | * variable pointed to by tp. | |
519 | */ | |
520 | int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) | |
521 | { | |
522 | struct hrtimer_base *bases; | |
523 | ||
c0a31329 | 524 | bases = per_cpu(hrtimer_bases, raw_smp_processor_id()); |
e2787630 | 525 | *tp = ktime_to_timespec(bases[which_clock].resolution); |
c0a31329 TG |
526 | |
527 | return 0; | |
528 | } | |
529 | ||
530 | /* | |
531 | * Expire the per base hrtimer-queue: | |
532 | */ | |
533 | static inline void run_hrtimer_queue(struct hrtimer_base *base) | |
534 | { | |
535 | ktime_t now = base->get_time(); | |
288867ec | 536 | struct rb_node *node; |
c0a31329 TG |
537 | |
538 | spin_lock_irq(&base->lock); | |
539 | ||
288867ec | 540 | while ((node = base->first)) { |
c0a31329 TG |
541 | struct hrtimer *timer; |
542 | int (*fn)(void *); | |
543 | int restart; | |
544 | void *data; | |
545 | ||
288867ec | 546 | timer = rb_entry(node, struct hrtimer, node); |
c0a31329 TG |
547 | if (now.tv64 <= timer->expires.tv64) |
548 | break; | |
549 | ||
550 | fn = timer->function; | |
551 | data = timer->data; | |
552 | set_curr_timer(base, timer); | |
553 | __remove_hrtimer(timer, base); | |
554 | spin_unlock_irq(&base->lock); | |
555 | ||
556 | /* | |
557 | * fn == NULL is special case for the simplest timer | |
558 | * variant - wake up process and do not restart: | |
559 | */ | |
560 | if (!fn) { | |
561 | wake_up_process(data); | |
562 | restart = HRTIMER_NORESTART; | |
563 | } else | |
564 | restart = fn(data); | |
565 | ||
566 | spin_lock_irq(&base->lock); | |
567 | ||
568 | if (restart == HRTIMER_RESTART) | |
569 | enqueue_hrtimer(timer, base); | |
570 | else | |
571 | timer->state = HRTIMER_EXPIRED; | |
572 | } | |
573 | set_curr_timer(base, NULL); | |
574 | spin_unlock_irq(&base->lock); | |
575 | } | |
576 | ||
577 | /* | |
578 | * Called from timer softirq every jiffy, expire hrtimers: | |
579 | */ | |
580 | void hrtimer_run_queues(void) | |
581 | { | |
582 | struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); | |
583 | int i; | |
584 | ||
585 | for (i = 0; i < MAX_HRTIMER_BASES; i++) | |
586 | run_hrtimer_queue(&base[i]); | |
587 | } | |
588 | ||
10c94ec1 TG |
589 | /* |
590 | * Sleep related functions: | |
591 | */ | |
592 | ||
593 | /** | |
594 | * schedule_hrtimer - sleep until timeout | |
595 | * | |
596 | * @timer: hrtimer variable initialized with the correct clock base | |
597 | * @mode: timeout value is abs/rel | |
598 | * | |
599 | * Make the current task sleep until @timeout is | |
600 | * elapsed. | |
601 | * | |
602 | * You can set the task state as follows - | |
603 | * | |
604 | * %TASK_UNINTERRUPTIBLE - at least @timeout is guaranteed to | |
605 | * pass before the routine returns. The routine will return 0 | |
606 | * | |
607 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
608 | * delivered to the current task. In this case the remaining time | |
609 | * will be returned | |
610 | * | |
611 | * The current task state is guaranteed to be TASK_RUNNING when this | |
612 | * routine returns. | |
613 | */ | |
614 | static ktime_t __sched | |
615 | schedule_hrtimer(struct hrtimer *timer, const enum hrtimer_mode mode) | |
616 | { | |
617 | /* fn stays NULL, meaning single-shot wakeup: */ | |
618 | timer->data = current; | |
619 | ||
620 | hrtimer_start(timer, timer->expires, mode); | |
621 | ||
622 | schedule(); | |
623 | hrtimer_cancel(timer); | |
624 | ||
625 | /* Return the remaining time: */ | |
626 | if (timer->state != HRTIMER_EXPIRED) | |
627 | return ktime_sub(timer->expires, timer->base->get_time()); | |
628 | else | |
629 | return (ktime_t) {.tv64 = 0 }; | |
630 | } | |
631 | ||
632 | static inline ktime_t __sched | |
633 | schedule_hrtimer_interruptible(struct hrtimer *timer, | |
634 | const enum hrtimer_mode mode) | |
635 | { | |
636 | set_current_state(TASK_INTERRUPTIBLE); | |
637 | ||
638 | return schedule_hrtimer(timer, mode); | |
639 | } | |
640 | ||
641 | static long __sched | |
642 | nanosleep_restart(struct restart_block *restart, clockid_t clockid) | |
643 | { | |
644 | struct timespec __user *rmtp, tu; | |
645 | void *rfn_save = restart->fn; | |
646 | struct hrtimer timer; | |
647 | ktime_t rem; | |
648 | ||
649 | restart->fn = do_no_restart_syscall; | |
650 | ||
651 | hrtimer_init(&timer, clockid); | |
652 | ||
653 | timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0; | |
654 | ||
655 | rem = schedule_hrtimer_interruptible(&timer, HRTIMER_ABS); | |
656 | ||
657 | if (rem.tv64 <= 0) | |
658 | return 0; | |
659 | ||
660 | rmtp = (struct timespec __user *) restart->arg2; | |
661 | tu = ktime_to_timespec(rem); | |
662 | if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu))) | |
663 | return -EFAULT; | |
664 | ||
665 | restart->fn = rfn_save; | |
666 | ||
667 | /* The other values in restart are already filled in */ | |
668 | return -ERESTART_RESTARTBLOCK; | |
669 | } | |
670 | ||
671 | static long __sched nanosleep_restart_mono(struct restart_block *restart) | |
672 | { | |
673 | return nanosleep_restart(restart, CLOCK_MONOTONIC); | |
674 | } | |
675 | ||
676 | static long __sched nanosleep_restart_real(struct restart_block *restart) | |
677 | { | |
678 | return nanosleep_restart(restart, CLOCK_REALTIME); | |
679 | } | |
680 | ||
681 | long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, | |
682 | const enum hrtimer_mode mode, const clockid_t clockid) | |
683 | { | |
684 | struct restart_block *restart; | |
685 | struct hrtimer timer; | |
686 | struct timespec tu; | |
687 | ktime_t rem; | |
688 | ||
689 | hrtimer_init(&timer, clockid); | |
690 | ||
691 | timer.expires = timespec_to_ktime(*rqtp); | |
692 | ||
693 | rem = schedule_hrtimer_interruptible(&timer, mode); | |
694 | if (rem.tv64 <= 0) | |
695 | return 0; | |
696 | ||
697 | /* Absolute timers do not update the rmtp value: */ | |
698 | if (mode == HRTIMER_ABS) | |
699 | return -ERESTARTNOHAND; | |
700 | ||
701 | tu = ktime_to_timespec(rem); | |
702 | ||
703 | if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu))) | |
704 | return -EFAULT; | |
705 | ||
706 | restart = ¤t_thread_info()->restart_block; | |
707 | restart->fn = (clockid == CLOCK_MONOTONIC) ? | |
708 | nanosleep_restart_mono : nanosleep_restart_real; | |
709 | restart->arg0 = timer.expires.tv64 & 0xFFFFFFFF; | |
710 | restart->arg1 = timer.expires.tv64 >> 32; | |
711 | restart->arg2 = (unsigned long) rmtp; | |
712 | ||
713 | return -ERESTART_RESTARTBLOCK; | |
714 | } | |
715 | ||
6ba1b912 TG |
716 | asmlinkage long |
717 | sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) | |
718 | { | |
719 | struct timespec tu; | |
720 | ||
721 | if (copy_from_user(&tu, rqtp, sizeof(tu))) | |
722 | return -EFAULT; | |
723 | ||
724 | if (!timespec_valid(&tu)) | |
725 | return -EINVAL; | |
726 | ||
727 | return hrtimer_nanosleep(&tu, rmtp, HRTIMER_REL, CLOCK_MONOTONIC); | |
728 | } | |
729 | ||
c0a31329 TG |
730 | /* |
731 | * Functions related to boot-time initialization: | |
732 | */ | |
733 | static void __devinit init_hrtimers_cpu(int cpu) | |
734 | { | |
735 | struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu); | |
736 | int i; | |
737 | ||
738 | for (i = 0; i < MAX_HRTIMER_BASES; i++) { | |
739 | spin_lock_init(&base->lock); | |
c0a31329 TG |
740 | base++; |
741 | } | |
742 | } | |
743 | ||
744 | #ifdef CONFIG_HOTPLUG_CPU | |
745 | ||
746 | static void migrate_hrtimer_list(struct hrtimer_base *old_base, | |
747 | struct hrtimer_base *new_base) | |
748 | { | |
749 | struct hrtimer *timer; | |
750 | struct rb_node *node; | |
751 | ||
752 | while ((node = rb_first(&old_base->active))) { | |
753 | timer = rb_entry(node, struct hrtimer, node); | |
754 | __remove_hrtimer(timer, old_base); | |
755 | timer->base = new_base; | |
756 | enqueue_hrtimer(timer, new_base); | |
757 | } | |
758 | } | |
759 | ||
760 | static void migrate_hrtimers(int cpu) | |
761 | { | |
762 | struct hrtimer_base *old_base, *new_base; | |
763 | int i; | |
764 | ||
765 | BUG_ON(cpu_online(cpu)); | |
766 | old_base = per_cpu(hrtimer_bases, cpu); | |
767 | new_base = get_cpu_var(hrtimer_bases); | |
768 | ||
769 | local_irq_disable(); | |
770 | ||
771 | for (i = 0; i < MAX_HRTIMER_BASES; i++) { | |
772 | ||
773 | spin_lock(&new_base->lock); | |
774 | spin_lock(&old_base->lock); | |
775 | ||
776 | BUG_ON(old_base->curr_timer); | |
777 | ||
778 | migrate_hrtimer_list(old_base, new_base); | |
779 | ||
780 | spin_unlock(&old_base->lock); | |
781 | spin_unlock(&new_base->lock); | |
782 | old_base++; | |
783 | new_base++; | |
784 | } | |
785 | ||
786 | local_irq_enable(); | |
787 | put_cpu_var(hrtimer_bases); | |
788 | } | |
789 | #endif /* CONFIG_HOTPLUG_CPU */ | |
790 | ||
791 | static int __devinit hrtimer_cpu_notify(struct notifier_block *self, | |
792 | unsigned long action, void *hcpu) | |
793 | { | |
794 | long cpu = (long)hcpu; | |
795 | ||
796 | switch (action) { | |
797 | ||
798 | case CPU_UP_PREPARE: | |
799 | init_hrtimers_cpu(cpu); | |
800 | break; | |
801 | ||
802 | #ifdef CONFIG_HOTPLUG_CPU | |
803 | case CPU_DEAD: | |
804 | migrate_hrtimers(cpu); | |
805 | break; | |
806 | #endif | |
807 | ||
808 | default: | |
809 | break; | |
810 | } | |
811 | ||
812 | return NOTIFY_OK; | |
813 | } | |
814 | ||
815 | static struct notifier_block __devinitdata hrtimers_nb = { | |
816 | .notifier_call = hrtimer_cpu_notify, | |
817 | }; | |
818 | ||
819 | void __init hrtimers_init(void) | |
820 | { | |
821 | hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, | |
822 | (void *)(long)smp_processor_id()); | |
823 | register_cpu_notifier(&hrtimers_nb); | |
824 | } | |
825 |