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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 | * | |
66188fae TG |
24 | * Help, testing, suggestions, bugfixes, improvements were |
25 | * provided by: | |
26 | * | |
27 | * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel | |
28 | * et. al. | |
29 | * | |
c0a31329 TG |
30 | * For licencing details see kernel-base/COPYING |
31 | */ | |
32 | ||
33 | #include <linux/cpu.h> | |
34 | #include <linux/module.h> | |
35 | #include <linux/percpu.h> | |
36 | #include <linux/hrtimer.h> | |
37 | #include <linux/notifier.h> | |
38 | #include <linux/syscalls.h> | |
39 | #include <linux/interrupt.h> | |
40 | ||
41 | #include <asm/uaccess.h> | |
42 | ||
43 | /** | |
44 | * ktime_get - get the monotonic time in ktime_t format | |
45 | * | |
46 | * returns the time in ktime_t format | |
47 | */ | |
48 | static ktime_t ktime_get(void) | |
49 | { | |
50 | struct timespec now; | |
51 | ||
52 | ktime_get_ts(&now); | |
53 | ||
54 | return timespec_to_ktime(now); | |
55 | } | |
56 | ||
57 | /** | |
58 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
59 | * | |
60 | * returns the time in ktime_t format | |
61 | */ | |
62 | static ktime_t ktime_get_real(void) | |
63 | { | |
64 | struct timespec now; | |
65 | ||
66 | getnstimeofday(&now); | |
67 | ||
68 | return timespec_to_ktime(now); | |
69 | } | |
70 | ||
71 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
72 | ||
73 | /* | |
74 | * The timer bases: | |
7978672c GA |
75 | * |
76 | * Note: If we want to add new timer bases, we have to skip the two | |
77 | * clock ids captured by the cpu-timers. We do this by holding empty | |
78 | * entries rather than doing math adjustment of the clock ids. | |
79 | * This ensures that we capture erroneous accesses to these clock ids | |
80 | * rather than moving them into the range of valid clock id's. | |
c0a31329 TG |
81 | */ |
82 | ||
83 | #define MAX_HRTIMER_BASES 2 | |
84 | ||
85 | static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) = | |
86 | { | |
87 | { | |
88 | .index = CLOCK_REALTIME, | |
89 | .get_time = &ktime_get_real, | |
90 | .resolution = KTIME_REALTIME_RES, | |
91 | }, | |
92 | { | |
93 | .index = CLOCK_MONOTONIC, | |
94 | .get_time = &ktime_get, | |
95 | .resolution = KTIME_MONOTONIC_RES, | |
96 | }, | |
97 | }; | |
98 | ||
99 | /** | |
100 | * ktime_get_ts - get the monotonic clock in timespec format | |
c0a31329 TG |
101 | * @ts: pointer to timespec variable |
102 | * | |
103 | * The function calculates the monotonic clock from the realtime | |
104 | * clock and the wall_to_monotonic offset and stores the result | |
72fd4a35 | 105 | * in normalized timespec format in the variable pointed to by @ts. |
c0a31329 TG |
106 | */ |
107 | void ktime_get_ts(struct timespec *ts) | |
108 | { | |
109 | struct timespec tomono; | |
110 | unsigned long seq; | |
111 | ||
112 | do { | |
113 | seq = read_seqbegin(&xtime_lock); | |
114 | getnstimeofday(ts); | |
115 | tomono = wall_to_monotonic; | |
116 | ||
117 | } while (read_seqretry(&xtime_lock, seq)); | |
118 | ||
119 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
120 | ts->tv_nsec + tomono.tv_nsec); | |
121 | } | |
69778e32 | 122 | EXPORT_SYMBOL_GPL(ktime_get_ts); |
c0a31329 | 123 | |
92127c7a TG |
124 | /* |
125 | * Get the coarse grained time at the softirq based on xtime and | |
126 | * wall_to_monotonic. | |
127 | */ | |
128 | static void hrtimer_get_softirq_time(struct hrtimer_base *base) | |
129 | { | |
130 | ktime_t xtim, tomono; | |
f4304ab2 | 131 | struct timespec xts; |
92127c7a TG |
132 | unsigned long seq; |
133 | ||
134 | do { | |
135 | seq = read_seqbegin(&xtime_lock); | |
f4304ab2 | 136 | #ifdef CONFIG_NO_HZ |
137 | getnstimeofday(&xts); | |
138 | #else | |
139 | xts = xtime; | |
140 | #endif | |
92127c7a TG |
141 | } while (read_seqretry(&xtime_lock, seq)); |
142 | ||
f4304ab2 | 143 | xtim = timespec_to_ktime(xts); |
144 | tomono = timespec_to_ktime(wall_to_monotonic); | |
92127c7a TG |
145 | base[CLOCK_REALTIME].softirq_time = xtim; |
146 | base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono); | |
147 | } | |
148 | ||
c0a31329 TG |
149 | /* |
150 | * Functions and macros which are different for UP/SMP systems are kept in a | |
151 | * single place | |
152 | */ | |
153 | #ifdef CONFIG_SMP | |
154 | ||
155 | #define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0) | |
156 | ||
157 | /* | |
158 | * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock | |
159 | * means that all timers which are tied to this base via timer->base are | |
160 | * locked, and the base itself is locked too. | |
161 | * | |
162 | * So __run_timers/migrate_timers can safely modify all timers which could | |
163 | * be found on the lists/queues. | |
164 | * | |
165 | * When the timer's base is locked, and the timer removed from list, it is | |
166 | * possible to set timer->base = NULL and drop the lock: the timer remains | |
167 | * locked. | |
168 | */ | |
169 | static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer, | |
170 | unsigned long *flags) | |
171 | { | |
172 | struct hrtimer_base *base; | |
173 | ||
174 | for (;;) { | |
175 | base = timer->base; | |
176 | if (likely(base != NULL)) { | |
177 | spin_lock_irqsave(&base->lock, *flags); | |
178 | if (likely(base == timer->base)) | |
179 | return base; | |
180 | /* The timer has migrated to another CPU: */ | |
181 | spin_unlock_irqrestore(&base->lock, *flags); | |
182 | } | |
183 | cpu_relax(); | |
184 | } | |
185 | } | |
186 | ||
187 | /* | |
188 | * Switch the timer base to the current CPU when possible. | |
189 | */ | |
190 | static inline struct hrtimer_base * | |
191 | switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) | |
192 | { | |
193 | struct hrtimer_base *new_base; | |
194 | ||
3773dc92 | 195 | new_base = &__get_cpu_var(hrtimer_bases)[base->index]; |
c0a31329 TG |
196 | |
197 | if (base != new_base) { | |
198 | /* | |
199 | * We are trying to schedule the timer on the local CPU. | |
200 | * However we can't change timer's base while it is running, | |
201 | * so we keep it on the same CPU. No hassle vs. reprogramming | |
202 | * the event source in the high resolution case. The softirq | |
203 | * code will take care of this when the timer function has | |
204 | * completed. There is no conflict as we hold the lock until | |
205 | * the timer is enqueued. | |
206 | */ | |
207 | if (unlikely(base->curr_timer == timer)) | |
208 | return base; | |
209 | ||
210 | /* See the comment in lock_timer_base() */ | |
211 | timer->base = NULL; | |
212 | spin_unlock(&base->lock); | |
213 | spin_lock(&new_base->lock); | |
214 | timer->base = new_base; | |
215 | } | |
216 | return new_base; | |
217 | } | |
218 | ||
219 | #else /* CONFIG_SMP */ | |
220 | ||
221 | #define set_curr_timer(b, t) do { } while (0) | |
222 | ||
223 | static inline struct hrtimer_base * | |
224 | lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
225 | { | |
226 | struct hrtimer_base *base = timer->base; | |
227 | ||
228 | spin_lock_irqsave(&base->lock, *flags); | |
229 | ||
230 | return base; | |
231 | } | |
232 | ||
233 | #define switch_hrtimer_base(t, b) (b) | |
234 | ||
235 | #endif /* !CONFIG_SMP */ | |
236 | ||
237 | /* | |
238 | * Functions for the union type storage format of ktime_t which are | |
239 | * too large for inlining: | |
240 | */ | |
241 | #if BITS_PER_LONG < 64 | |
242 | # ifndef CONFIG_KTIME_SCALAR | |
243 | /** | |
244 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable | |
c0a31329 TG |
245 | * @kt: addend |
246 | * @nsec: the scalar nsec value to add | |
247 | * | |
248 | * Returns the sum of kt and nsec in ktime_t format | |
249 | */ | |
250 | ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) | |
251 | { | |
252 | ktime_t tmp; | |
253 | ||
254 | if (likely(nsec < NSEC_PER_SEC)) { | |
255 | tmp.tv64 = nsec; | |
256 | } else { | |
257 | unsigned long rem = do_div(nsec, NSEC_PER_SEC); | |
258 | ||
259 | tmp = ktime_set((long)nsec, rem); | |
260 | } | |
261 | ||
262 | return ktime_add(kt, tmp); | |
263 | } | |
264 | ||
265 | #else /* CONFIG_KTIME_SCALAR */ | |
266 | ||
267 | # endif /* !CONFIG_KTIME_SCALAR */ | |
268 | ||
269 | /* | |
270 | * Divide a ktime value by a nanosecond value | |
271 | */ | |
df869b63 | 272 | static unsigned long ktime_divns(const ktime_t kt, s64 div) |
c0a31329 TG |
273 | { |
274 | u64 dclc, inc, dns; | |
275 | int sft = 0; | |
276 | ||
277 | dclc = dns = ktime_to_ns(kt); | |
278 | inc = div; | |
279 | /* Make sure the divisor is less than 2^32: */ | |
280 | while (div >> 32) { | |
281 | sft++; | |
282 | div >>= 1; | |
283 | } | |
284 | dclc >>= sft; | |
285 | do_div(dclc, (unsigned long) div); | |
286 | ||
287 | return (unsigned long) dclc; | |
288 | } | |
289 | ||
290 | #else /* BITS_PER_LONG < 64 */ | |
291 | # define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) | |
292 | #endif /* BITS_PER_LONG >= 64 */ | |
293 | ||
411187fb JS |
294 | /* |
295 | * Timekeeping resumed notification | |
296 | */ | |
297 | void hrtimer_notify_resume(void) | |
298 | { | |
299 | clock_was_set(); | |
300 | } | |
301 | ||
c0a31329 TG |
302 | /* |
303 | * Counterpart to lock_timer_base above: | |
304 | */ | |
305 | static inline | |
306 | void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
307 | { | |
308 | spin_unlock_irqrestore(&timer->base->lock, *flags); | |
309 | } | |
310 | ||
311 | /** | |
312 | * hrtimer_forward - forward the timer expiry | |
c0a31329 | 313 | * @timer: hrtimer to forward |
44f21475 | 314 | * @now: forward past this time |
c0a31329 TG |
315 | * @interval: the interval to forward |
316 | * | |
317 | * Forward the timer expiry so it will expire in the future. | |
8dca6f33 | 318 | * Returns the number of overruns. |
c0a31329 TG |
319 | */ |
320 | unsigned long | |
44f21475 | 321 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval) |
c0a31329 TG |
322 | { |
323 | unsigned long orun = 1; | |
44f21475 | 324 | ktime_t delta; |
c0a31329 TG |
325 | |
326 | delta = ktime_sub(now, timer->expires); | |
327 | ||
328 | if (delta.tv64 < 0) | |
329 | return 0; | |
330 | ||
c9db4fa1 TG |
331 | if (interval.tv64 < timer->base->resolution.tv64) |
332 | interval.tv64 = timer->base->resolution.tv64; | |
333 | ||
c0a31329 | 334 | if (unlikely(delta.tv64 >= interval.tv64)) { |
df869b63 | 335 | s64 incr = ktime_to_ns(interval); |
c0a31329 TG |
336 | |
337 | orun = ktime_divns(delta, incr); | |
338 | timer->expires = ktime_add_ns(timer->expires, incr * orun); | |
339 | if (timer->expires.tv64 > now.tv64) | |
340 | return orun; | |
341 | /* | |
342 | * This (and the ktime_add() below) is the | |
343 | * correction for exact: | |
344 | */ | |
345 | orun++; | |
346 | } | |
347 | timer->expires = ktime_add(timer->expires, interval); | |
348 | ||
349 | return orun; | |
350 | } | |
351 | ||
352 | /* | |
353 | * enqueue_hrtimer - internal function to (re)start a timer | |
354 | * | |
355 | * The timer is inserted in expiry order. Insertion into the | |
356 | * red black tree is O(log(n)). Must hold the base lock. | |
357 | */ | |
358 | static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
359 | { | |
360 | struct rb_node **link = &base->active.rb_node; | |
c0a31329 TG |
361 | struct rb_node *parent = NULL; |
362 | struct hrtimer *entry; | |
363 | ||
364 | /* | |
365 | * Find the right place in the rbtree: | |
366 | */ | |
367 | while (*link) { | |
368 | parent = *link; | |
369 | entry = rb_entry(parent, struct hrtimer, node); | |
370 | /* | |
371 | * We dont care about collisions. Nodes with | |
372 | * the same expiry time stay together. | |
373 | */ | |
374 | if (timer->expires.tv64 < entry->expires.tv64) | |
375 | link = &(*link)->rb_left; | |
288867ec | 376 | else |
c0a31329 | 377 | link = &(*link)->rb_right; |
c0a31329 TG |
378 | } |
379 | ||
380 | /* | |
288867ec TG |
381 | * Insert the timer to the rbtree and check whether it |
382 | * replaces the first pending timer | |
c0a31329 TG |
383 | */ |
384 | rb_link_node(&timer->node, parent, link); | |
385 | rb_insert_color(&timer->node, &base->active); | |
c0a31329 | 386 | |
288867ec TG |
387 | if (!base->first || timer->expires.tv64 < |
388 | rb_entry(base->first, struct hrtimer, node)->expires.tv64) | |
389 | base->first = &timer->node; | |
390 | } | |
c0a31329 TG |
391 | |
392 | /* | |
393 | * __remove_hrtimer - internal function to remove a timer | |
394 | * | |
395 | * Caller must hold the base lock. | |
396 | */ | |
397 | static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
398 | { | |
399 | /* | |
288867ec TG |
400 | * Remove the timer from the rbtree and replace the |
401 | * first entry pointer if necessary. | |
c0a31329 | 402 | */ |
288867ec TG |
403 | if (base->first == &timer->node) |
404 | base->first = rb_next(&timer->node); | |
c0a31329 | 405 | rb_erase(&timer->node, &base->active); |
ed198cb4 | 406 | rb_set_parent(&timer->node, &timer->node); |
c0a31329 TG |
407 | } |
408 | ||
409 | /* | |
410 | * remove hrtimer, called with base lock held | |
411 | */ | |
412 | static inline int | |
413 | remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
414 | { | |
415 | if (hrtimer_active(timer)) { | |
416 | __remove_hrtimer(timer, base); | |
c0a31329 TG |
417 | return 1; |
418 | } | |
419 | return 0; | |
420 | } | |
421 | ||
422 | /** | |
423 | * hrtimer_start - (re)start an relative timer on the current CPU | |
c0a31329 TG |
424 | * @timer: the timer to be added |
425 | * @tim: expiry time | |
426 | * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) | |
427 | * | |
428 | * Returns: | |
429 | * 0 on success | |
430 | * 1 when the timer was active | |
431 | */ | |
432 | int | |
433 | hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) | |
434 | { | |
435 | struct hrtimer_base *base, *new_base; | |
436 | unsigned long flags; | |
437 | int ret; | |
438 | ||
439 | base = lock_hrtimer_base(timer, &flags); | |
440 | ||
441 | /* Remove an active timer from the queue: */ | |
442 | ret = remove_hrtimer(timer, base); | |
443 | ||
444 | /* Switch the timer base, if necessary: */ | |
445 | new_base = switch_hrtimer_base(timer, base); | |
446 | ||
06027bdd | 447 | if (mode == HRTIMER_REL) { |
c0a31329 | 448 | tim = ktime_add(tim, new_base->get_time()); |
06027bdd IM |
449 | /* |
450 | * CONFIG_TIME_LOW_RES is a temporary way for architectures | |
451 | * to signal that they simply return xtime in | |
452 | * do_gettimeoffset(). In this case we want to round up by | |
453 | * resolution when starting a relative timer, to avoid short | |
454 | * timeouts. This will go away with the GTOD framework. | |
455 | */ | |
456 | #ifdef CONFIG_TIME_LOW_RES | |
457 | tim = ktime_add(tim, base->resolution); | |
458 | #endif | |
459 | } | |
c0a31329 TG |
460 | timer->expires = tim; |
461 | ||
462 | enqueue_hrtimer(timer, new_base); | |
463 | ||
464 | unlock_hrtimer_base(timer, &flags); | |
465 | ||
466 | return ret; | |
467 | } | |
8d16b764 | 468 | EXPORT_SYMBOL_GPL(hrtimer_start); |
c0a31329 TG |
469 | |
470 | /** | |
471 | * hrtimer_try_to_cancel - try to deactivate a timer | |
c0a31329 TG |
472 | * @timer: hrtimer to stop |
473 | * | |
474 | * Returns: | |
475 | * 0 when the timer was not active | |
476 | * 1 when the timer was active | |
477 | * -1 when the timer is currently excuting the callback function and | |
fa9799e3 | 478 | * cannot be stopped |
c0a31329 TG |
479 | */ |
480 | int hrtimer_try_to_cancel(struct hrtimer *timer) | |
481 | { | |
482 | struct hrtimer_base *base; | |
483 | unsigned long flags; | |
484 | int ret = -1; | |
485 | ||
486 | base = lock_hrtimer_base(timer, &flags); | |
487 | ||
488 | if (base->curr_timer != timer) | |
489 | ret = remove_hrtimer(timer, base); | |
490 | ||
491 | unlock_hrtimer_base(timer, &flags); | |
492 | ||
493 | return ret; | |
494 | ||
495 | } | |
8d16b764 | 496 | EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel); |
c0a31329 TG |
497 | |
498 | /** | |
499 | * hrtimer_cancel - cancel a timer and wait for the handler to finish. | |
c0a31329 TG |
500 | * @timer: the timer to be cancelled |
501 | * | |
502 | * Returns: | |
503 | * 0 when the timer was not active | |
504 | * 1 when the timer was active | |
505 | */ | |
506 | int hrtimer_cancel(struct hrtimer *timer) | |
507 | { | |
508 | for (;;) { | |
509 | int ret = hrtimer_try_to_cancel(timer); | |
510 | ||
511 | if (ret >= 0) | |
512 | return ret; | |
5ef37b19 | 513 | cpu_relax(); |
c0a31329 TG |
514 | } |
515 | } | |
8d16b764 | 516 | EXPORT_SYMBOL_GPL(hrtimer_cancel); |
c0a31329 TG |
517 | |
518 | /** | |
519 | * hrtimer_get_remaining - get remaining time for the timer | |
c0a31329 TG |
520 | * @timer: the timer to read |
521 | */ | |
522 | ktime_t hrtimer_get_remaining(const struct hrtimer *timer) | |
523 | { | |
524 | struct hrtimer_base *base; | |
525 | unsigned long flags; | |
526 | ktime_t rem; | |
527 | ||
528 | base = lock_hrtimer_base(timer, &flags); | |
529 | rem = ktime_sub(timer->expires, timer->base->get_time()); | |
530 | unlock_hrtimer_base(timer, &flags); | |
531 | ||
532 | return rem; | |
533 | } | |
8d16b764 | 534 | EXPORT_SYMBOL_GPL(hrtimer_get_remaining); |
c0a31329 | 535 | |
69239749 TL |
536 | #ifdef CONFIG_NO_IDLE_HZ |
537 | /** | |
538 | * hrtimer_get_next_event - get the time until next expiry event | |
539 | * | |
540 | * Returns the delta to the next expiry event or KTIME_MAX if no timer | |
541 | * is pending. | |
542 | */ | |
543 | ktime_t hrtimer_get_next_event(void) | |
544 | { | |
545 | struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); | |
546 | ktime_t delta, mindelta = { .tv64 = KTIME_MAX }; | |
547 | unsigned long flags; | |
548 | int i; | |
549 | ||
550 | for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) { | |
551 | struct hrtimer *timer; | |
552 | ||
553 | spin_lock_irqsave(&base->lock, flags); | |
554 | if (!base->first) { | |
555 | spin_unlock_irqrestore(&base->lock, flags); | |
556 | continue; | |
557 | } | |
558 | timer = rb_entry(base->first, struct hrtimer, node); | |
559 | delta.tv64 = timer->expires.tv64; | |
560 | spin_unlock_irqrestore(&base->lock, flags); | |
561 | delta = ktime_sub(delta, base->get_time()); | |
562 | if (delta.tv64 < mindelta.tv64) | |
563 | mindelta.tv64 = delta.tv64; | |
564 | } | |
565 | if (mindelta.tv64 < 0) | |
566 | mindelta.tv64 = 0; | |
567 | return mindelta; | |
568 | } | |
569 | #endif | |
570 | ||
c0a31329 | 571 | /** |
7978672c | 572 | * hrtimer_init - initialize a timer to the given clock |
7978672c | 573 | * @timer: the timer to be initialized |
c0a31329 | 574 | * @clock_id: the clock to be used |
7978672c | 575 | * @mode: timer mode abs/rel |
c0a31329 | 576 | */ |
7978672c GA |
577 | void hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
578 | enum hrtimer_mode mode) | |
c0a31329 TG |
579 | { |
580 | struct hrtimer_base *bases; | |
581 | ||
7978672c GA |
582 | memset(timer, 0, sizeof(struct hrtimer)); |
583 | ||
bfe5d834 | 584 | bases = __raw_get_cpu_var(hrtimer_bases); |
c0a31329 | 585 | |
7978672c GA |
586 | if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS) |
587 | clock_id = CLOCK_MONOTONIC; | |
588 | ||
589 | timer->base = &bases[clock_id]; | |
ed198cb4 | 590 | rb_set_parent(&timer->node, &timer->node); |
c0a31329 | 591 | } |
8d16b764 | 592 | EXPORT_SYMBOL_GPL(hrtimer_init); |
c0a31329 TG |
593 | |
594 | /** | |
595 | * hrtimer_get_res - get the timer resolution for a clock | |
c0a31329 TG |
596 | * @which_clock: which clock to query |
597 | * @tp: pointer to timespec variable to store the resolution | |
598 | * | |
72fd4a35 RD |
599 | * Store the resolution of the clock selected by @which_clock in the |
600 | * variable pointed to by @tp. | |
c0a31329 TG |
601 | */ |
602 | int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) | |
603 | { | |
604 | struct hrtimer_base *bases; | |
605 | ||
bfe5d834 | 606 | bases = __raw_get_cpu_var(hrtimer_bases); |
e2787630 | 607 | *tp = ktime_to_timespec(bases[which_clock].resolution); |
c0a31329 TG |
608 | |
609 | return 0; | |
610 | } | |
8d16b764 | 611 | EXPORT_SYMBOL_GPL(hrtimer_get_res); |
c0a31329 TG |
612 | |
613 | /* | |
614 | * Expire the per base hrtimer-queue: | |
615 | */ | |
616 | static inline void run_hrtimer_queue(struct hrtimer_base *base) | |
617 | { | |
288867ec | 618 | struct rb_node *node; |
c0a31329 | 619 | |
3055adda DS |
620 | if (!base->first) |
621 | return; | |
622 | ||
92127c7a TG |
623 | if (base->get_softirq_time) |
624 | base->softirq_time = base->get_softirq_time(); | |
625 | ||
c0a31329 TG |
626 | spin_lock_irq(&base->lock); |
627 | ||
288867ec | 628 | while ((node = base->first)) { |
c0a31329 | 629 | struct hrtimer *timer; |
05cfb614 | 630 | int (*fn)(struct hrtimer *); |
c0a31329 | 631 | int restart; |
c0a31329 | 632 | |
288867ec | 633 | timer = rb_entry(node, struct hrtimer, node); |
92127c7a | 634 | if (base->softirq_time.tv64 <= timer->expires.tv64) |
c0a31329 TG |
635 | break; |
636 | ||
637 | fn = timer->function; | |
c0a31329 TG |
638 | set_curr_timer(base, timer); |
639 | __remove_hrtimer(timer, base); | |
640 | spin_unlock_irq(&base->lock); | |
641 | ||
05cfb614 | 642 | restart = fn(timer); |
c0a31329 TG |
643 | |
644 | spin_lock_irq(&base->lock); | |
645 | ||
b75f7a51 RZ |
646 | if (restart != HRTIMER_NORESTART) { |
647 | BUG_ON(hrtimer_active(timer)); | |
c0a31329 | 648 | enqueue_hrtimer(timer, base); |
b75f7a51 | 649 | } |
c0a31329 TG |
650 | } |
651 | set_curr_timer(base, NULL); | |
652 | spin_unlock_irq(&base->lock); | |
653 | } | |
654 | ||
655 | /* | |
656 | * Called from timer softirq every jiffy, expire hrtimers: | |
657 | */ | |
658 | void hrtimer_run_queues(void) | |
659 | { | |
660 | struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); | |
661 | int i; | |
662 | ||
92127c7a TG |
663 | hrtimer_get_softirq_time(base); |
664 | ||
c0a31329 TG |
665 | for (i = 0; i < MAX_HRTIMER_BASES; i++) |
666 | run_hrtimer_queue(&base[i]); | |
667 | } | |
668 | ||
10c94ec1 TG |
669 | /* |
670 | * Sleep related functions: | |
671 | */ | |
00362e33 TG |
672 | static int hrtimer_wakeup(struct hrtimer *timer) |
673 | { | |
674 | struct hrtimer_sleeper *t = | |
675 | container_of(timer, struct hrtimer_sleeper, timer); | |
676 | struct task_struct *task = t->task; | |
677 | ||
678 | t->task = NULL; | |
679 | if (task) | |
680 | wake_up_process(task); | |
681 | ||
682 | return HRTIMER_NORESTART; | |
683 | } | |
684 | ||
36c8b586 | 685 | void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) |
00362e33 TG |
686 | { |
687 | sl->timer.function = hrtimer_wakeup; | |
688 | sl->task = task; | |
689 | } | |
690 | ||
669d7868 | 691 | static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode) |
432569bb | 692 | { |
669d7868 | 693 | hrtimer_init_sleeper(t, current); |
10c94ec1 | 694 | |
432569bb RZ |
695 | do { |
696 | set_current_state(TASK_INTERRUPTIBLE); | |
697 | hrtimer_start(&t->timer, t->timer.expires, mode); | |
698 | ||
699 | schedule(); | |
700 | ||
669d7868 TG |
701 | hrtimer_cancel(&t->timer); |
702 | mode = HRTIMER_ABS; | |
703 | ||
704 | } while (t->task && !signal_pending(current)); | |
432569bb | 705 | |
669d7868 | 706 | return t->task == NULL; |
10c94ec1 TG |
707 | } |
708 | ||
1711ef38 | 709 | long __sched hrtimer_nanosleep_restart(struct restart_block *restart) |
10c94ec1 | 710 | { |
669d7868 | 711 | struct hrtimer_sleeper t; |
ea13dbc8 IM |
712 | struct timespec __user *rmtp; |
713 | struct timespec tu; | |
432569bb | 714 | ktime_t time; |
10c94ec1 TG |
715 | |
716 | restart->fn = do_no_restart_syscall; | |
717 | ||
1711ef38 TA |
718 | hrtimer_init(&t.timer, restart->arg0, HRTIMER_ABS); |
719 | t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2; | |
10c94ec1 | 720 | |
432569bb | 721 | if (do_nanosleep(&t, HRTIMER_ABS)) |
10c94ec1 TG |
722 | return 0; |
723 | ||
1711ef38 | 724 | rmtp = (struct timespec __user *) restart->arg1; |
432569bb RZ |
725 | if (rmtp) { |
726 | time = ktime_sub(t.timer.expires, t.timer.base->get_time()); | |
727 | if (time.tv64 <= 0) | |
728 | return 0; | |
729 | tu = ktime_to_timespec(time); | |
730 | if (copy_to_user(rmtp, &tu, sizeof(tu))) | |
731 | return -EFAULT; | |
732 | } | |
10c94ec1 | 733 | |
1711ef38 | 734 | restart->fn = hrtimer_nanosleep_restart; |
10c94ec1 TG |
735 | |
736 | /* The other values in restart are already filled in */ | |
737 | return -ERESTART_RESTARTBLOCK; | |
738 | } | |
739 | ||
10c94ec1 TG |
740 | long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, |
741 | const enum hrtimer_mode mode, const clockid_t clockid) | |
742 | { | |
743 | struct restart_block *restart; | |
669d7868 | 744 | struct hrtimer_sleeper t; |
10c94ec1 TG |
745 | struct timespec tu; |
746 | ktime_t rem; | |
747 | ||
432569bb RZ |
748 | hrtimer_init(&t.timer, clockid, mode); |
749 | t.timer.expires = timespec_to_ktime(*rqtp); | |
750 | if (do_nanosleep(&t, mode)) | |
10c94ec1 TG |
751 | return 0; |
752 | ||
7978672c | 753 | /* Absolute timers do not update the rmtp value and restart: */ |
10c94ec1 TG |
754 | if (mode == HRTIMER_ABS) |
755 | return -ERESTARTNOHAND; | |
756 | ||
432569bb RZ |
757 | if (rmtp) { |
758 | rem = ktime_sub(t.timer.expires, t.timer.base->get_time()); | |
759 | if (rem.tv64 <= 0) | |
760 | return 0; | |
761 | tu = ktime_to_timespec(rem); | |
762 | if (copy_to_user(rmtp, &tu, sizeof(tu))) | |
763 | return -EFAULT; | |
764 | } | |
10c94ec1 TG |
765 | |
766 | restart = ¤t_thread_info()->restart_block; | |
1711ef38 TA |
767 | restart->fn = hrtimer_nanosleep_restart; |
768 | restart->arg0 = (unsigned long) t.timer.base->index; | |
769 | restart->arg1 = (unsigned long) rmtp; | |
770 | restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF; | |
771 | restart->arg3 = t.timer.expires.tv64 >> 32; | |
10c94ec1 TG |
772 | |
773 | return -ERESTART_RESTARTBLOCK; | |
774 | } | |
775 | ||
6ba1b912 TG |
776 | asmlinkage long |
777 | sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) | |
778 | { | |
779 | struct timespec tu; | |
780 | ||
781 | if (copy_from_user(&tu, rqtp, sizeof(tu))) | |
782 | return -EFAULT; | |
783 | ||
784 | if (!timespec_valid(&tu)) | |
785 | return -EINVAL; | |
786 | ||
787 | return hrtimer_nanosleep(&tu, rmtp, HRTIMER_REL, CLOCK_MONOTONIC); | |
788 | } | |
789 | ||
c0a31329 TG |
790 | /* |
791 | * Functions related to boot-time initialization: | |
792 | */ | |
793 | static void __devinit init_hrtimers_cpu(int cpu) | |
794 | { | |
795 | struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu); | |
796 | int i; | |
797 | ||
54365524 | 798 | for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) { |
c0a31329 | 799 | spin_lock_init(&base->lock); |
54365524 IM |
800 | lockdep_set_class(&base->lock, &base->lock_key); |
801 | } | |
c0a31329 TG |
802 | } |
803 | ||
804 | #ifdef CONFIG_HOTPLUG_CPU | |
805 | ||
806 | static void migrate_hrtimer_list(struct hrtimer_base *old_base, | |
807 | struct hrtimer_base *new_base) | |
808 | { | |
809 | struct hrtimer *timer; | |
810 | struct rb_node *node; | |
811 | ||
812 | while ((node = rb_first(&old_base->active))) { | |
813 | timer = rb_entry(node, struct hrtimer, node); | |
814 | __remove_hrtimer(timer, old_base); | |
815 | timer->base = new_base; | |
816 | enqueue_hrtimer(timer, new_base); | |
817 | } | |
818 | } | |
819 | ||
820 | static void migrate_hrtimers(int cpu) | |
821 | { | |
822 | struct hrtimer_base *old_base, *new_base; | |
823 | int i; | |
824 | ||
825 | BUG_ON(cpu_online(cpu)); | |
826 | old_base = per_cpu(hrtimer_bases, cpu); | |
827 | new_base = get_cpu_var(hrtimer_bases); | |
828 | ||
829 | local_irq_disable(); | |
830 | ||
831 | for (i = 0; i < MAX_HRTIMER_BASES; i++) { | |
832 | ||
833 | spin_lock(&new_base->lock); | |
834 | spin_lock(&old_base->lock); | |
835 | ||
836 | BUG_ON(old_base->curr_timer); | |
837 | ||
838 | migrate_hrtimer_list(old_base, new_base); | |
839 | ||
840 | spin_unlock(&old_base->lock); | |
841 | spin_unlock(&new_base->lock); | |
842 | old_base++; | |
843 | new_base++; | |
844 | } | |
845 | ||
846 | local_irq_enable(); | |
847 | put_cpu_var(hrtimer_bases); | |
848 | } | |
849 | #endif /* CONFIG_HOTPLUG_CPU */ | |
850 | ||
8c78f307 | 851 | static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self, |
c0a31329 TG |
852 | unsigned long action, void *hcpu) |
853 | { | |
854 | long cpu = (long)hcpu; | |
855 | ||
856 | switch (action) { | |
857 | ||
858 | case CPU_UP_PREPARE: | |
859 | init_hrtimers_cpu(cpu); | |
860 | break; | |
861 | ||
862 | #ifdef CONFIG_HOTPLUG_CPU | |
863 | case CPU_DEAD: | |
864 | migrate_hrtimers(cpu); | |
865 | break; | |
866 | #endif | |
867 | ||
868 | default: | |
869 | break; | |
870 | } | |
871 | ||
872 | return NOTIFY_OK; | |
873 | } | |
874 | ||
8c78f307 | 875 | static struct notifier_block __cpuinitdata hrtimers_nb = { |
c0a31329 TG |
876 | .notifier_call = hrtimer_cpu_notify, |
877 | }; | |
878 | ||
879 | void __init hrtimers_init(void) | |
880 | { | |
881 | hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, | |
882 | (void *)(long)smp_processor_id()); | |
883 | register_cpu_notifier(&hrtimers_nb); | |
884 | } | |
885 |