Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0
2 : : /*
3 : : * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
4 : : * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
5 : : * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
6 : : *
7 : : * High-resolution kernel timers
8 : : *
9 : : * In contrast to the low-resolution timeout API, aka timer wheel,
10 : : * hrtimers provide finer resolution and accuracy depending on system
11 : : * configuration and capabilities.
12 : : *
13 : : * Started by: Thomas Gleixner and Ingo Molnar
14 : : *
15 : : * Credits:
16 : : * Based on the original timer wheel code
17 : : *
18 : : * Help, testing, suggestions, bugfixes, improvements were
19 : : * provided by:
20 : : *
21 : : * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
22 : : * et. al.
23 : : */
24 : :
25 : : #include <linux/cpu.h>
26 : : #include <linux/export.h>
27 : : #include <linux/percpu.h>
28 : : #include <linux/hrtimer.h>
29 : : #include <linux/notifier.h>
30 : : #include <linux/syscalls.h>
31 : : #include <linux/interrupt.h>
32 : : #include <linux/tick.h>
33 : : #include <linux/err.h>
34 : : #include <linux/debugobjects.h>
35 : : #include <linux/sched/signal.h>
36 : : #include <linux/sched/sysctl.h>
37 : : #include <linux/sched/rt.h>
38 : : #include <linux/sched/deadline.h>
39 : : #include <linux/sched/nohz.h>
40 : : #include <linux/sched/debug.h>
41 : : #include <linux/timer.h>
42 : : #include <linux/freezer.h>
43 : : #include <linux/compat.h>
44 : :
45 : : #include <linux/uaccess.h>
46 : :
47 : : #include <trace/events/timer.h>
48 : :
49 : : #include "tick-internal.h"
50 : :
51 : : /*
52 : : * Masks for selecting the soft and hard context timers from
53 : : * cpu_base->active
54 : : */
55 : : #define MASK_SHIFT (HRTIMER_BASE_MONOTONIC_SOFT)
56 : : #define HRTIMER_ACTIVE_HARD ((1U << MASK_SHIFT) - 1)
57 : : #define HRTIMER_ACTIVE_SOFT (HRTIMER_ACTIVE_HARD << MASK_SHIFT)
58 : : #define HRTIMER_ACTIVE_ALL (HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
59 : :
60 : : /*
61 : : * The timer bases:
62 : : *
63 : : * There are more clockids than hrtimer bases. Thus, we index
64 : : * into the timer bases by the hrtimer_base_type enum. When trying
65 : : * to reach a base using a clockid, hrtimer_clockid_to_base()
66 : : * is used to convert from clockid to the proper hrtimer_base_type.
67 : : */
68 : : DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
69 : : {
70 : : .lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
71 : : .clock_base =
72 : : {
73 : : {
74 : : .index = HRTIMER_BASE_MONOTONIC,
75 : : .clockid = CLOCK_MONOTONIC,
76 : : .get_time = &ktime_get,
77 : : },
78 : : {
79 : : .index = HRTIMER_BASE_REALTIME,
80 : : .clockid = CLOCK_REALTIME,
81 : : .get_time = &ktime_get_real,
82 : : },
83 : : {
84 : : .index = HRTIMER_BASE_BOOTTIME,
85 : : .clockid = CLOCK_BOOTTIME,
86 : : .get_time = &ktime_get_boottime,
87 : : },
88 : : {
89 : : .index = HRTIMER_BASE_TAI,
90 : : .clockid = CLOCK_TAI,
91 : : .get_time = &ktime_get_clocktai,
92 : : },
93 : : {
94 : : .index = HRTIMER_BASE_MONOTONIC_SOFT,
95 : : .clockid = CLOCK_MONOTONIC,
96 : : .get_time = &ktime_get,
97 : : },
98 : : {
99 : : .index = HRTIMER_BASE_REALTIME_SOFT,
100 : : .clockid = CLOCK_REALTIME,
101 : : .get_time = &ktime_get_real,
102 : : },
103 : : {
104 : : .index = HRTIMER_BASE_BOOTTIME_SOFT,
105 : : .clockid = CLOCK_BOOTTIME,
106 : : .get_time = &ktime_get_boottime,
107 : : },
108 : : {
109 : : .index = HRTIMER_BASE_TAI_SOFT,
110 : : .clockid = CLOCK_TAI,
111 : : .get_time = &ktime_get_clocktai,
112 : : },
113 : : }
114 : : };
115 : :
116 : : static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
117 : : /* Make sure we catch unsupported clockids */
118 : : [0 ... MAX_CLOCKS - 1] = HRTIMER_MAX_CLOCK_BASES,
119 : :
120 : : [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
121 : : [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
122 : : [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
123 : : [CLOCK_TAI] = HRTIMER_BASE_TAI,
124 : : };
125 : :
126 : : /*
127 : : * Functions and macros which are different for UP/SMP systems are kept in a
128 : : * single place
129 : : */
130 : : #ifdef CONFIG_SMP
131 : :
132 : : /*
133 : : * We require the migration_base for lock_hrtimer_base()/switch_hrtimer_base()
134 : : * such that hrtimer_callback_running() can unconditionally dereference
135 : : * timer->base->cpu_base
136 : : */
137 : : static struct hrtimer_cpu_base migration_cpu_base = {
138 : : .clock_base = { { .cpu_base = &migration_cpu_base, }, },
139 : : };
140 : :
141 : : #define migration_base migration_cpu_base.clock_base[0]
142 : :
143 : : static inline bool is_migration_base(struct hrtimer_clock_base *base)
144 : : {
145 : : return base == &migration_base;
146 : : }
147 : :
148 : : /*
149 : : * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
150 : : * means that all timers which are tied to this base via timer->base are
151 : : * locked, and the base itself is locked too.
152 : : *
153 : : * So __run_timers/migrate_timers can safely modify all timers which could
154 : : * be found on the lists/queues.
155 : : *
156 : : * When the timer's base is locked, and the timer removed from list, it is
157 : : * possible to set timer->base = &migration_base and drop the lock: the timer
158 : : * remains locked.
159 : : */
160 : : static
161 : 4193895 : struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
162 : : unsigned long *flags)
163 : : {
164 : : struct hrtimer_clock_base *base;
165 : :
166 : : for (;;) {
167 : 4193895 : base = READ_ONCE(timer->base);
168 [ + + ]: 4193895 : if (likely(base != &migration_base)) {
169 : 4193896 : raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
170 [ + - ]: 4194965 : if (likely(base == timer->base))
171 : 4194965 : return base;
172 : : /* The timer has migrated to another CPU: */
173 : 0 : raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
174 : : }
175 : 230 : cpu_relax();
176 : 0 : }
177 : : }
178 : :
179 : : /*
180 : : * We do not migrate the timer when it is expiring before the next
181 : : * event on the target cpu. When high resolution is enabled, we cannot
182 : : * reprogram the target cpu hardware and we would cause it to fire
183 : : * late. To keep it simple, we handle the high resolution enabled and
184 : : * disabled case similar.
185 : : *
186 : : * Called with cpu_base->lock of target cpu held.
187 : : */
188 : : static int
189 : : hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
190 : : {
191 : : ktime_t expires;
192 : :
193 : 0 : expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
194 : 0 : return expires < new_base->cpu_base->expires_next;
195 : : }
196 : :
197 : : static inline
198 : 2706764 : struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
199 : : int pinned)
200 : : {
201 : : #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
202 [ + + + + ]: 2706589 : if (static_branch_likely(&timers_migration_enabled) && !pinned)
203 : 1013748 : return &per_cpu(hrtimer_bases, get_nohz_timer_target());
204 : : #endif
205 : : return base;
206 : : }
207 : :
208 : : /*
209 : : * We switch the timer base to a power-optimized selected CPU target,
210 : : * if:
211 : : * - NO_HZ_COMMON is enabled
212 : : * - timer migration is enabled
213 : : * - the timer callback is not running
214 : : * - the timer is not the first expiring timer on the new target
215 : : *
216 : : * If one of the above requirements is not fulfilled we move the timer
217 : : * to the current CPU or leave it on the previously assigned CPU if
218 : : * the timer callback is currently running.
219 : : */
220 : : static inline struct hrtimer_clock_base *
221 : 2706758 : switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
222 : : int pinned)
223 : : {
224 : : struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
225 : : struct hrtimer_clock_base *new_base;
226 : 2706758 : int basenum = base->index;
227 : :
228 : 5413516 : this_cpu_base = this_cpu_ptr(&hrtimer_bases);
229 : 2706758 : new_cpu_base = get_target_base(this_cpu_base, pinned);
230 : : again:
231 : 2706314 : new_base = &new_cpu_base->clock_base[basenum];
232 : :
233 [ + + ]: 2706314 : if (base != new_base) {
234 : : /*
235 : : * We are trying to move timer to new_base.
236 : : * However we can't change timer's base while it is running,
237 : : * so we keep it on the same CPU. No hassle vs. reprogramming
238 : : * the event source in the high resolution case. The softirq
239 : : * code will take care of this when the timer function has
240 : : * completed. There is no conflict as we hold the lock until
241 : : * the timer is enqueued.
242 : : */
243 [ + + ]: 14929 : if (unlikely(hrtimer_callback_running(timer)))
244 : : return base;
245 : :
246 : : /* See the comment in lock_hrtimer_base() */
247 : 13993 : WRITE_ONCE(timer->base, &migration_base);
248 : 13993 : raw_spin_unlock(&base->cpu_base->lock);
249 : 13994 : raw_spin_lock(&new_base->cpu_base->lock);
250 : :
251 [ - + # # ]: 13998 : if (new_cpu_base != this_cpu_base &&
252 : : hrtimer_check_target(timer, new_base)) {
253 : : raw_spin_unlock(&new_base->cpu_base->lock);
254 : 0 : raw_spin_lock(&base->cpu_base->lock);
255 : : new_cpu_base = this_cpu_base;
256 : 0 : WRITE_ONCE(timer->base, base);
257 : 0 : goto again;
258 : : }
259 : 13998 : WRITE_ONCE(timer->base, new_base);
260 : : } else {
261 [ - + # # ]: 2691385 : if (new_cpu_base != this_cpu_base &&
262 : : hrtimer_check_target(timer, new_base)) {
263 : : new_cpu_base = this_cpu_base;
264 : : goto again;
265 : : }
266 : : }
267 : 2704898 : return new_base;
268 : : }
269 : :
270 : : #else /* CONFIG_SMP */
271 : :
272 : : static inline bool is_migration_base(struct hrtimer_clock_base *base)
273 : : {
274 : : return false;
275 : : }
276 : :
277 : : static inline struct hrtimer_clock_base *
278 : : lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
279 : : {
280 : : struct hrtimer_clock_base *base = timer->base;
281 : :
282 : : raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
283 : :
284 : : return base;
285 : : }
286 : :
287 : : # define switch_hrtimer_base(t, b, p) (b)
288 : :
289 : : #endif /* !CONFIG_SMP */
290 : :
291 : : /*
292 : : * Functions for the union type storage format of ktime_t which are
293 : : * too large for inlining:
294 : : */
295 : : #if BITS_PER_LONG < 64
296 : : /*
297 : : * Divide a ktime value by a nanosecond value
298 : : */
299 : 313767 : s64 __ktime_divns(const ktime_t kt, s64 div)
300 : : {
301 : : int sft = 0;
302 : : s64 dclc;
303 : : u64 tmp;
304 : :
305 : : dclc = ktime_to_ns(kt);
306 : 313767 : tmp = dclc < 0 ? -dclc : dclc;
307 : :
308 : : /* Make sure the divisor is less than 2^32: */
309 [ - + ]: 627534 : while (div >> 32) {
310 : 0 : sft++;
311 : 0 : div >>= 1;
312 : : }
313 : 313767 : tmp >>= sft;
314 [ - + # # : 313767 : do_div(tmp, (unsigned long) div);
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+ + ]
315 [ - + ]: 313518 : return dclc < 0 ? -tmp : tmp;
316 : : }
317 : : EXPORT_SYMBOL_GPL(__ktime_divns);
318 : : #endif /* BITS_PER_LONG >= 64 */
319 : :
320 : : /*
321 : : * Add two ktime values and do a safety check for overflow:
322 : : */
323 : 23806 : ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
324 : : {
325 : 8999752 : ktime_t res = ktime_add_unsafe(lhs, rhs);
326 : :
327 : : /*
328 : : * We use KTIME_SEC_MAX here, the maximum timeout which we can
329 : : * return to user space in a timespec:
330 : : */
331 [ + + + + : 8999752 : if (res < 0 || res < lhs || res < rhs)
+ - - + +
+ + + + +
- + + - -
+ + - + +
+ - + + ]
332 : : res = ktime_set(KTIME_SEC_MAX, 0);
333 : :
334 : 23806 : return res;
335 : : }
336 : :
337 : : EXPORT_SYMBOL_GPL(ktime_add_safe);
338 : :
339 : : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
340 : :
341 : : static struct debug_obj_descr hrtimer_debug_descr;
342 : :
343 : : static void *hrtimer_debug_hint(void *addr)
344 : : {
345 : : return ((struct hrtimer *) addr)->function;
346 : : }
347 : :
348 : : /*
349 : : * fixup_init is called when:
350 : : * - an active object is initialized
351 : : */
352 : : static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
353 : : {
354 : : struct hrtimer *timer = addr;
355 : :
356 : : switch (state) {
357 : : case ODEBUG_STATE_ACTIVE:
358 : : hrtimer_cancel(timer);
359 : : debug_object_init(timer, &hrtimer_debug_descr);
360 : : return true;
361 : : default:
362 : : return false;
363 : : }
364 : : }
365 : :
366 : : /*
367 : : * fixup_activate is called when:
368 : : * - an active object is activated
369 : : * - an unknown non-static object is activated
370 : : */
371 : : static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
372 : : {
373 : : switch (state) {
374 : : case ODEBUG_STATE_ACTIVE:
375 : : WARN_ON(1);
376 : : /* fall through */
377 : : default:
378 : : return false;
379 : : }
380 : : }
381 : :
382 : : /*
383 : : * fixup_free is called when:
384 : : * - an active object is freed
385 : : */
386 : : static bool hrtimer_fixup_free(void *addr, enum debug_obj_state state)
387 : : {
388 : : struct hrtimer *timer = addr;
389 : :
390 : : switch (state) {
391 : : case ODEBUG_STATE_ACTIVE:
392 : : hrtimer_cancel(timer);
393 : : debug_object_free(timer, &hrtimer_debug_descr);
394 : : return true;
395 : : default:
396 : : return false;
397 : : }
398 : : }
399 : :
400 : : static struct debug_obj_descr hrtimer_debug_descr = {
401 : : .name = "hrtimer",
402 : : .debug_hint = hrtimer_debug_hint,
403 : : .fixup_init = hrtimer_fixup_init,
404 : : .fixup_activate = hrtimer_fixup_activate,
405 : : .fixup_free = hrtimer_fixup_free,
406 : : };
407 : :
408 : : static inline void debug_hrtimer_init(struct hrtimer *timer)
409 : : {
410 : : debug_object_init(timer, &hrtimer_debug_descr);
411 : : }
412 : :
413 : : static inline void debug_hrtimer_activate(struct hrtimer *timer,
414 : : enum hrtimer_mode mode)
415 : : {
416 : : debug_object_activate(timer, &hrtimer_debug_descr);
417 : : }
418 : :
419 : : static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
420 : : {
421 : : debug_object_deactivate(timer, &hrtimer_debug_descr);
422 : : }
423 : :
424 : : static inline void debug_hrtimer_free(struct hrtimer *timer)
425 : : {
426 : : debug_object_free(timer, &hrtimer_debug_descr);
427 : : }
428 : :
429 : : static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
430 : : enum hrtimer_mode mode);
431 : :
432 : : void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
433 : : enum hrtimer_mode mode)
434 : : {
435 : : debug_object_init_on_stack(timer, &hrtimer_debug_descr);
436 : : __hrtimer_init(timer, clock_id, mode);
437 : : }
438 : : EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
439 : :
440 : : static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
441 : : clockid_t clock_id, enum hrtimer_mode mode);
442 : :
443 : : void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
444 : : clockid_t clock_id, enum hrtimer_mode mode)
445 : : {
446 : : debug_object_init_on_stack(&sl->timer, &hrtimer_debug_descr);
447 : : __hrtimer_init_sleeper(sl, clock_id, mode);
448 : : }
449 : : EXPORT_SYMBOL_GPL(hrtimer_init_sleeper_on_stack);
450 : :
451 : : void destroy_hrtimer_on_stack(struct hrtimer *timer)
452 : : {
453 : : debug_object_free(timer, &hrtimer_debug_descr);
454 : : }
455 : : EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
456 : :
457 : : #else
458 : :
459 : : static inline void debug_hrtimer_init(struct hrtimer *timer) { }
460 : : static inline void debug_hrtimer_activate(struct hrtimer *timer,
461 : : enum hrtimer_mode mode) { }
462 : : static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
463 : : #endif
464 : :
465 : : static inline void
466 : : debug_init(struct hrtimer *timer, clockid_t clockid,
467 : : enum hrtimer_mode mode)
468 : : {
469 : : debug_hrtimer_init(timer);
470 : 1586720 : trace_hrtimer_init(timer, clockid, mode);
471 : : }
472 : :
473 : : static inline void debug_activate(struct hrtimer *timer,
474 : : enum hrtimer_mode mode)
475 : : {
476 : : debug_hrtimer_activate(timer, mode);
477 : 5329646 : trace_hrtimer_start(timer, mode);
478 : : }
479 : :
480 : : static inline void debug_deactivate(struct hrtimer *timer)
481 : : {
482 : : debug_hrtimer_deactivate(timer);
483 : 4144671 : trace_hrtimer_cancel(timer);
484 : : }
485 : :
486 : : static struct hrtimer_clock_base *
487 : : __next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active)
488 : : {
489 : : unsigned int idx;
490 : :
491 [ + + + + ]: 21925579 : if (!*active)
492 : : return NULL;
493 : :
494 : : idx = __ffs(*active);
495 : 10567742 : *active &= ~(1U << idx);
496 : :
497 : 10567742 : return &cpu_base->clock_base[idx];
498 : : }
499 : :
500 : : #define for_each_active_base(base, cpu_base, active) \
501 : : while ((base = __next_base((cpu_base), &(active))))
502 : :
503 : 8689116 : static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
504 : : const struct hrtimer *exclude,
505 : : unsigned int active,
506 : : ktime_t expires_next)
507 : : {
508 : : struct hrtimer_clock_base *base;
509 : : ktime_t expires;
510 : :
511 [ + + ]: 23610774 : for_each_active_base(base, cpu_base, active) {
512 : : struct timerqueue_node *next;
513 : : struct hrtimer *timer;
514 : :
515 : : next = timerqueue_getnext(&base->active);
516 : : timer = container_of(next, struct hrtimer, node);
517 [ + + ]: 6426474 : if (timer == exclude) {
518 : : /* Get to the next timer in the queue. */
519 : 193932 : next = timerqueue_iterate_next(next);
520 [ # # ]: 0 : if (!next)
521 : 0 : continue;
522 : :
523 : : timer = container_of(next, struct hrtimer, node);
524 : : }
525 : 6232542 : expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
526 [ + + ]: 6232542 : if (expires < expires_next) {
527 : : expires_next = expires;
528 : :
529 : : /* Skip cpu_base update if a timer is being excluded. */
530 [ - + ]: 4146499 : if (exclude)
531 : 0 : continue;
532 : :
533 [ - + ]: 4146499 : if (timer->is_soft)
534 : 0 : cpu_base->softirq_next_timer = timer;
535 : : else
536 : 4146499 : cpu_base->next_timer = timer;
537 : : }
538 : : }
539 : : /*
540 : : * clock_was_set() might have changed base->offset of any of
541 : : * the clock bases so the result might be negative. Fix it up
542 : : * to prevent a false positive in clockevents_program_event().
543 : : */
544 [ + + ]: 8495184 : if (expires_next < 0)
545 : : expires_next = 0;
546 : 8495184 : return expires_next;
547 : : }
548 : :
549 : : /*
550 : : * Recomputes cpu_base::*next_timer and returns the earliest expires_next but
551 : : * does not set cpu_base::*expires_next, that is done by hrtimer_reprogram.
552 : : *
553 : : * When a softirq is pending, we can ignore the HRTIMER_ACTIVE_SOFT bases,
554 : : * those timers will get run whenever the softirq gets handled, at the end of
555 : : * hrtimer_run_softirq(), hrtimer_update_softirq_timer() will re-add these bases.
556 : : *
557 : : * Therefore softirq values are those from the HRTIMER_ACTIVE_SOFT clock bases.
558 : : * The !softirq values are the minima across HRTIMER_ACTIVE_ALL, unless an actual
559 : : * softirq is pending, in which case they're the minima of HRTIMER_ACTIVE_HARD.
560 : : *
561 : : * @active_mask must be one of:
562 : : * - HRTIMER_ACTIVE_ALL,
563 : : * - HRTIMER_ACTIVE_SOFT, or
564 : : * - HRTIMER_ACTIVE_HARD.
565 : : */
566 : : static ktime_t
567 : 4585430 : __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_mask)
568 : : {
569 : : unsigned int active;
570 : : struct hrtimer *next_timer = NULL;
571 : : ktime_t expires_next = KTIME_MAX;
572 : :
573 [ + + + + ]: 4585430 : if (!cpu_base->softirq_activated && (active_mask & HRTIMER_ACTIVE_SOFT)) {
574 : 4102905 : active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
575 : 4102905 : cpu_base->softirq_next_timer = NULL;
576 : 4102905 : expires_next = __hrtimer_next_event_base(cpu_base, NULL,
577 : : active, KTIME_MAX);
578 : :
579 : 4466624 : next_timer = cpu_base->softirq_next_timer;
580 : : }
581 : :
582 [ + + ]: 4949149 : if (active_mask & HRTIMER_ACTIVE_HARD) {
583 : 4276556 : active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
584 : 4276556 : cpu_base->next_timer = next_timer;
585 : 4276556 : expires_next = __hrtimer_next_event_base(cpu_base, NULL, active,
586 : : expires_next);
587 : : }
588 : :
589 : 5163488 : return expires_next;
590 : : }
591 : :
592 : 3267594 : static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
593 : : {
594 : 3267594 : ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
595 : 3267594 : ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
596 : 3267594 : ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
597 : :
598 : 3267594 : ktime_t now = ktime_get_update_offsets_now(&base->clock_was_set_seq,
599 : : offs_real, offs_boot, offs_tai);
600 : :
601 : 3004077 : base->clock_base[HRTIMER_BASE_REALTIME_SOFT].offset = *offs_real;
602 : 3004077 : base->clock_base[HRTIMER_BASE_BOOTTIME_SOFT].offset = *offs_boot;
603 : 3004077 : base->clock_base[HRTIMER_BASE_TAI_SOFT].offset = *offs_tai;
604 : :
605 : 3004077 : return now;
606 : : }
607 : :
608 : : /*
609 : : * Is the high resolution mode active ?
610 : : */
611 : : static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
612 : : {
613 : : return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
614 : 101902077 : cpu_base->hres_active : 0;
615 : : }
616 : :
617 : : static inline int hrtimer_hres_active(void)
618 : : {
619 : : return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
620 : : }
621 : :
622 : : /*
623 : : * Reprogram the event source with checking both queues for the
624 : : * next event
625 : : * Called with interrupts disabled and base->lock held
626 : : */
627 : : static void
628 : 1359382 : hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
629 : : {
630 : : ktime_t expires_next;
631 : :
632 : : /*
633 : : * Find the current next expiration time.
634 : : */
635 : 1359382 : expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
636 : :
637 [ + + - + ]: 1359500 : if (cpu_base->next_timer && cpu_base->next_timer->is_soft) {
638 : : /*
639 : : * When the softirq is activated, hrtimer has to be
640 : : * programmed with the first hard hrtimer because soft
641 : : * timer interrupt could occur too late.
642 : : */
643 [ # # ]: 0 : if (cpu_base->softirq_activated)
644 : 0 : expires_next = __hrtimer_get_next_event(cpu_base,
645 : : HRTIMER_ACTIVE_HARD);
646 : : else
647 : 0 : cpu_base->softirq_expires_next = expires_next;
648 : : }
649 : :
650 [ + + + + ]: 1358102 : if (skip_equal && expires_next == cpu_base->expires_next)
651 : : return;
652 : :
653 : 1358590 : cpu_base->expires_next = expires_next;
654 : :
655 : : /*
656 : : * If hres is not active, hardware does not have to be
657 : : * reprogrammed yet.
658 : : *
659 : : * If a hang was detected in the last timer interrupt then we
660 : : * leave the hang delay active in the hardware. We want the
661 : : * system to make progress. That also prevents the following
662 : : * scenario:
663 : : * T1 expires 50ms from now
664 : : * T2 expires 5s from now
665 : : *
666 : : * T1 is removed, so this code is called and would reprogram
667 : : * the hardware to 5s from now. Any hrtimer_start after that
668 : : * will not reprogram the hardware due to hang_detected being
669 : : * set. So we'd effectivly block all timers until the T2 event
670 : : * fires.
671 : : */
672 [ + - + + ]: 1358590 : if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
673 : : return;
674 : :
675 : 1358976 : tick_program_event(cpu_base->expires_next, 1);
676 : : }
677 : :
678 : : /* High resolution timer related functions */
679 : : #ifdef CONFIG_HIGH_RES_TIMERS
680 : :
681 : : /*
682 : : * High resolution timer enabled ?
683 : : */
684 : : static bool hrtimer_hres_enabled __read_mostly = true;
685 : : unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
686 : : EXPORT_SYMBOL_GPL(hrtimer_resolution);
687 : :
688 : : /*
689 : : * Enable / Disable high resolution mode
690 : : */
691 : 0 : static int __init setup_hrtimer_hres(char *str)
692 : : {
693 : 0 : return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
694 : : }
695 : :
696 : : __setup("highres=", setup_hrtimer_hres);
697 : :
698 : : /*
699 : : * hrtimer_high_res_enabled - query, if the highres mode is enabled
700 : : */
701 : : static inline int hrtimer_is_hres_enabled(void)
702 : : {
703 : 22977 : return hrtimer_hres_enabled;
704 : : }
705 : :
706 : : /*
707 : : * Retrigger next event is called after clock was set
708 : : *
709 : : * Called with interrupts disabled via on_each_cpu()
710 : : */
711 : 2552 : static void retrigger_next_event(void *arg)
712 : : {
713 : 5104 : struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
714 : :
715 [ + + ]: 2552 : if (!__hrtimer_hres_active(base))
716 : 2812 : return;
717 : :
718 : 2886 : raw_spin_lock(&base->lock);
719 : 3026 : hrtimer_update_base(base);
720 : 2532 : hrtimer_force_reprogram(base, 0);
721 : : raw_spin_unlock(&base->lock);
722 : : }
723 : :
724 : : /*
725 : : * Switch to high resolution mode
726 : : */
727 : 828 : static void hrtimer_switch_to_hres(void)
728 : : {
729 : 1656 : struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
730 : :
731 [ - + ]: 828 : if (tick_init_highres()) {
732 : 0 : pr_warn("Could not switch to high resolution mode on CPU %u\n",
733 : : base->cpu);
734 : 828 : return;
735 : : }
736 : 828 : base->hres_active = 1;
737 : 828 : hrtimer_resolution = HIGH_RES_NSEC;
738 : :
739 : 828 : tick_setup_sched_timer();
740 : : /* "Retrigger" the interrupt to get things going */
741 : 828 : retrigger_next_event(NULL);
742 : : }
743 : :
744 : 0 : static void clock_was_set_work(struct work_struct *work)
745 : : {
746 : 0 : clock_was_set();
747 : 0 : }
748 : :
749 : : static DECLARE_WORK(hrtimer_work, clock_was_set_work);
750 : :
751 : : /*
752 : : * Called from timekeeping and resume code to reprogram the hrtimer
753 : : * interrupt device on all cpus.
754 : : */
755 : 0 : void clock_was_set_delayed(void)
756 : : {
757 : : schedule_work(&hrtimer_work);
758 : 0 : }
759 : :
760 : : #else
761 : :
762 : : static inline int hrtimer_is_hres_enabled(void) { return 0; }
763 : : static inline void hrtimer_switch_to_hres(void) { }
764 : : static inline void retrigger_next_event(void *arg) { }
765 : :
766 : : #endif /* CONFIG_HIGH_RES_TIMERS */
767 : :
768 : : /*
769 : : * When a timer is enqueued and expires earlier than the already enqueued
770 : : * timers, we have to check, whether it expires earlier than the timer for
771 : : * which the clock event device was armed.
772 : : *
773 : : * Called with interrupts disabled and base->cpu_base.lock held
774 : : */
775 : 1627733 : static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
776 : : {
777 : 3255466 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
778 : 1627733 : struct hrtimer_clock_base *base = timer->base;
779 : 1627733 : ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
780 : :
781 [ - + # # ]: 1627733 : WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
782 : :
783 : : /*
784 : : * CLOCK_REALTIME timer might be requested with an absolute
785 : : * expiry time which is less than base->offset. Set it to 0.
786 : : */
787 [ + + ]: 1628304 : if (expires < 0)
788 : : expires = 0;
789 : :
790 [ - + ]: 1628304 : if (timer->is_soft) {
791 : : /*
792 : : * soft hrtimer could be started on a remote CPU. In this
793 : : * case softirq_expires_next needs to be updated on the
794 : : * remote CPU. The soft hrtimer will not expire before the
795 : : * first hard hrtimer on the remote CPU -
796 : : * hrtimer_check_target() prevents this case.
797 : : */
798 : 0 : struct hrtimer_cpu_base *timer_cpu_base = base->cpu_base;
799 : :
800 [ # # ]: 0 : if (timer_cpu_base->softirq_activated)
801 : : return;
802 : :
803 [ # # ]: 0 : if (!ktime_before(expires, timer_cpu_base->softirq_expires_next))
804 : : return;
805 : :
806 : 0 : timer_cpu_base->softirq_next_timer = timer;
807 : 0 : timer_cpu_base->softirq_expires_next = expires;
808 : :
809 [ # # # # ]: 0 : if (!ktime_before(expires, timer_cpu_base->expires_next) ||
810 : : !reprogram)
811 : : return;
812 : : }
813 : :
814 : : /*
815 : : * If the timer is not on the current cpu, we cannot reprogram
816 : : * the other cpus clock event device.
817 : : */
818 [ + - ]: 1628304 : if (base->cpu_base != cpu_base)
819 : : return;
820 : :
821 : : /*
822 : : * If the hrtimer interrupt is running, then it will
823 : : * reevaluate the clock bases and reprogram the clock event
824 : : * device. The callbacks are always executed in hard interrupt
825 : : * context so we don't need an extra check for a running
826 : : * callback.
827 : : */
828 [ + + ]: 1628304 : if (cpu_base->in_hrtirq)
829 : : return;
830 : :
831 [ + + ]: 1627246 : if (expires >= cpu_base->expires_next)
832 : : return;
833 : :
834 : : /* Update the pointer to the next expiring timer */
835 : 1621670 : cpu_base->next_timer = timer;
836 : 1621670 : cpu_base->expires_next = expires;
837 : :
838 : : /*
839 : : * If hres is not active, hardware does not have to be
840 : : * programmed yet.
841 : : *
842 : : * If a hang was detected in the last timer interrupt then we
843 : : * do not schedule a timer which is earlier than the expiry
844 : : * which we enforced in the hang detection. We want the system
845 : : * to make progress.
846 : : */
847 [ + + + + ]: 1621670 : if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
848 : : return;
849 : :
850 : : /*
851 : : * Program the timer hardware. We enforce the expiry for
852 : : * events which are already in the past.
853 : : */
854 : 1621724 : tick_program_event(expires, 1);
855 : : }
856 : :
857 : : /*
858 : : * Clock realtime was set
859 : : *
860 : : * Change the offset of the realtime clock vs. the monotonic
861 : : * clock.
862 : : *
863 : : * We might have to reprogram the high resolution timer interrupt. On
864 : : * SMP we call the architecture specific code to retrigger _all_ high
865 : : * resolution timer interrupts. On UP we just disable interrupts and
866 : : * call the high resolution interrupt code.
867 : : */
868 : 621 : void clock_was_set(void)
869 : : {
870 : : #ifdef CONFIG_HIGH_RES_TIMERS
871 : : /* Retrigger the CPU local events everywhere */
872 : 621 : on_each_cpu(retrigger_next_event, NULL, 1);
873 : : #endif
874 : 621 : timerfd_clock_was_set();
875 : 621 : }
876 : :
877 : : /*
878 : : * During resume we might have to reprogram the high resolution timer
879 : : * interrupt on all online CPUs. However, all other CPUs will be
880 : : * stopped with IRQs interrupts disabled so the clock_was_set() call
881 : : * must be deferred.
882 : : */
883 : 0 : void hrtimers_resume(void)
884 : : {
885 : : lockdep_assert_irqs_disabled();
886 : : /* Retrigger on the local CPU */
887 : 0 : retrigger_next_event(NULL);
888 : : /* And schedule a retrigger for all others */
889 : : clock_was_set_delayed();
890 : 0 : }
891 : :
892 : : /*
893 : : * Counterpart to lock_hrtimer_base above:
894 : : */
895 : : static inline
896 : : void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
897 : : {
898 : 4195341 : raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
899 : : }
900 : :
901 : : /**
902 : : * hrtimer_forward - forward the timer expiry
903 : : * @timer: hrtimer to forward
904 : : * @now: forward past this time
905 : : * @interval: the interval to forward
906 : : *
907 : : * Forward the timer expiry so it will expire in the future.
908 : : * Returns the number of overruns.
909 : : *
910 : : * Can be safely called from the callback function of @timer. If
911 : : * called from other contexts @timer must neither be enqueued nor
912 : : * running the callback and the caller needs to take care of
913 : : * serialization.
914 : : *
915 : : * Note: This only updates the timer expiry value and does not requeue
916 : : * the timer.
917 : : */
918 : 3421125 : u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
919 : : {
920 : : u64 orun = 1;
921 : : ktime_t delta;
922 : :
923 : 3421125 : delta = ktime_sub(now, hrtimer_get_expires(timer));
924 : :
925 [ + + ]: 3421125 : if (delta < 0)
926 : : return 0;
927 : :
928 [ - + + - ]: 3025286 : if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
929 : : return 0;
930 : :
931 [ + + ]: 2793014 : if (interval < hrtimer_resolution)
932 : : interval = hrtimer_resolution;
933 : :
934 [ + + ]: 2793014 : if (unlikely(delta >= interval)) {
935 : : s64 incr = ktime_to_ns(interval);
936 : :
937 : 312126 : orun = ktime_divns(delta, incr);
938 : 312826 : hrtimer_add_expires_ns(timer, incr * orun);
939 [ + + ]: 312826 : if (hrtimer_get_expires_tv64(timer) > now)
940 : : return orun;
941 : : /*
942 : : * This (and the ktime_add() below) is the
943 : : * correction for exact:
944 : : */
945 : 312691 : orun++;
946 : : }
947 : 2793579 : hrtimer_add_expires(timer, interval);
948 : :
949 : 3183088 : return orun;
950 : : }
951 : : EXPORT_SYMBOL_GPL(hrtimer_forward);
952 : :
953 : : /*
954 : : * enqueue_hrtimer - internal function to (re)start a timer
955 : : *
956 : : * The timer is inserted in expiry order. Insertion into the
957 : : * red black tree is O(log(n)). Must hold the base lock.
958 : : *
959 : : * Returns 1 when the new timer is the leftmost timer in the tree.
960 : : */
961 : 5329646 : static int enqueue_hrtimer(struct hrtimer *timer,
962 : : struct hrtimer_clock_base *base,
963 : : enum hrtimer_mode mode)
964 : : {
965 : : debug_activate(timer, mode);
966 : :
967 : 4838133 : base->cpu_base->active_bases |= 1 << base->index;
968 : :
969 : : /* Pairs with the lockless read in hrtimer_is_queued() */
970 : : WRITE_ONCE(timer->state, HRTIMER_STATE_ENQUEUED);
971 : :
972 : 4838133 : return timerqueue_add(&base->active, &timer->node);
973 : : }
974 : :
975 : : /*
976 : : * __remove_hrtimer - internal function to remove a timer
977 : : *
978 : : * Caller must hold the base lock.
979 : : *
980 : : * High resolution timer mode reprograms the clock event device when the
981 : : * timer is the one which expires next. The caller can disable this by setting
982 : : * reprogram to zero. This is useful, when the context does a reprogramming
983 : : * anyway (e.g. timer interrupt)
984 : : */
985 : 4743401 : static void __remove_hrtimer(struct hrtimer *timer,
986 : : struct hrtimer_clock_base *base,
987 : : u8 newstate, int reprogram)
988 : : {
989 : 4743401 : struct hrtimer_cpu_base *cpu_base = base->cpu_base;
990 : 4743401 : u8 state = timer->state;
991 : :
992 : : /* Pairs with the lockless read in hrtimer_is_queued() */
993 : : WRITE_ONCE(timer->state, newstate);
994 [ + - ]: 4743401 : if (!(state & HRTIMER_STATE_ENQUEUED))
995 : 4451589 : return;
996 : :
997 [ + + ]: 4828053 : if (!timerqueue_del(&base->active, &timer->node))
998 : 504517 : cpu_base->active_bases &= ~(1 << base->index);
999 : :
1000 : : /*
1001 : : * Note: If reprogram is false we do not update
1002 : : * cpu_base->next_timer. This happens when we remove the first
1003 : : * timer on a remote cpu. No harm as we never dereference
1004 : : * cpu_base->next_timer. So the worst thing what can happen is
1005 : : * an superflous call to hrtimer_force_reprogram() on the
1006 : : * remote cpu later on if the same timer gets enqueued again.
1007 : : */
1008 [ + + + + ]: 4536028 : if (reprogram && timer == cpu_base->next_timer)
1009 : 1356006 : hrtimer_force_reprogram(cpu_base, 1);
1010 : : }
1011 : :
1012 : : /*
1013 : : * remove hrtimer, called with base lock held
1014 : : */
1015 : : static inline int
1016 : 4152188 : remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
1017 : : {
1018 : 4152188 : u8 state = timer->state;
1019 : :
1020 [ + + ]: 4152188 : if (state & HRTIMER_STATE_ENQUEUED) {
1021 : : int reprogram;
1022 : :
1023 : : /*
1024 : : * Remove the timer and force reprogramming when high
1025 : : * resolution mode is active and the timer is on the current
1026 : : * CPU. If we remove a timer on another CPU, reprogramming is
1027 : : * skipped. The interrupt event on this CPU is fired and
1028 : : * reprogramming happens in the interrupt handler. This is a
1029 : : * rare case and less expensive than a smp call.
1030 : : */
1031 : : debug_deactivate(timer);
1032 : 4491228 : reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
1033 : :
1034 [ + + ]: 2245614 : if (!restart)
1035 : : state = HRTIMER_STATE_INACTIVE;
1036 : :
1037 : 2245614 : __remove_hrtimer(timer, base, state, reprogram);
1038 : 2247823 : return 1;
1039 : : }
1040 : : return 0;
1041 : : }
1042 : :
1043 : : static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
1044 : : const enum hrtimer_mode mode)
1045 : : {
1046 : : #ifdef CONFIG_TIME_LOW_RES
1047 : : /*
1048 : : * CONFIG_TIME_LOW_RES indicates that the system has no way to return
1049 : : * granular time values. For relative timers we add hrtimer_resolution
1050 : : * (i.e. one jiffie) to prevent short timeouts.
1051 : : */
1052 : : timer->is_rel = mode & HRTIMER_MODE_REL;
1053 : : if (timer->is_rel)
1054 : : tim = ktime_add_safe(tim, hrtimer_resolution);
1055 : : #endif
1056 : : return tim;
1057 : : }
1058 : :
1059 : : static void
1060 : 0 : hrtimer_update_softirq_timer(struct hrtimer_cpu_base *cpu_base, bool reprogram)
1061 : : {
1062 : : ktime_t expires;
1063 : :
1064 : : /*
1065 : : * Find the next SOFT expiration.
1066 : : */
1067 : 0 : expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_SOFT);
1068 : :
1069 : : /*
1070 : : * reprogramming needs to be triggered, even if the next soft
1071 : : * hrtimer expires at the same time than the next hard
1072 : : * hrtimer. cpu_base->softirq_expires_next needs to be updated!
1073 : : */
1074 [ # # ]: 0 : if (expires == KTIME_MAX)
1075 : 0 : return;
1076 : :
1077 : : /*
1078 : : * cpu_base->*next_timer is recomputed by __hrtimer_get_next_event()
1079 : : * cpu_base->*expires_next is only set by hrtimer_reprogram()
1080 : : */
1081 : 0 : hrtimer_reprogram(cpu_base->softirq_next_timer, reprogram);
1082 : : }
1083 : :
1084 : 2706669 : static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1085 : : u64 delta_ns, const enum hrtimer_mode mode,
1086 : : struct hrtimer_clock_base *base)
1087 : : {
1088 : : struct hrtimer_clock_base *new_base;
1089 : :
1090 : : /* Remove an active timer from the queue: */
1091 : 2706669 : remove_hrtimer(timer, base, true);
1092 : :
1093 [ + + ]: 2706933 : if (mode & HRTIMER_MODE_REL)
1094 : 248476 : tim = ktime_add_safe(tim, base->get_time());
1095 : :
1096 : : tim = hrtimer_update_lowres(timer, tim, mode);
1097 : :
1098 : : hrtimer_set_expires_range_ns(timer, tim, delta_ns);
1099 : :
1100 : : /* Switch the timer base, if necessary: */
1101 : 2706920 : new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
1102 : :
1103 : 2706396 : return enqueue_hrtimer(timer, new_base, mode);
1104 : : }
1105 : :
1106 : : /**
1107 : : * hrtimer_start_range_ns - (re)start an hrtimer
1108 : : * @timer: the timer to be added
1109 : : * @tim: expiry time
1110 : : * @delta_ns: "slack" range for the timer
1111 : : * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
1112 : : * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
1113 : : * softirq based mode is considered for debug purpose only!
1114 : : */
1115 : 2704940 : void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1116 : : u64 delta_ns, const enum hrtimer_mode mode)
1117 : : {
1118 : : struct hrtimer_clock_base *base;
1119 : : unsigned long flags;
1120 : :
1121 : : /*
1122 : : * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
1123 : : * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard
1124 : : * expiry mode because unmarked timers are moved to softirq expiry.
1125 : : */
1126 : : if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1127 [ - + # # ]: 2704940 : WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);
1128 : : else
1129 : : WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard);
1130 : :
1131 : 2704940 : base = lock_hrtimer_base(timer, &flags);
1132 : :
1133 [ + + ]: 2706246 : if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))
1134 : 1628229 : hrtimer_reprogram(timer, true);
1135 : :
1136 : : unlock_hrtimer_base(timer, &flags);
1137 : 2707029 : }
1138 : : EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1139 : :
1140 : : /**
1141 : : * hrtimer_try_to_cancel - try to deactivate a timer
1142 : : * @timer: hrtimer to stop
1143 : : *
1144 : : * Returns:
1145 : : *
1146 : : * * 0 when the timer was not active
1147 : : * * 1 when the timer was active
1148 : : * * -1 when the timer is currently executing the callback function and
1149 : : * cannot be stopped
1150 : : */
1151 : 2317194 : int hrtimer_try_to_cancel(struct hrtimer *timer)
1152 : : {
1153 : : struct hrtimer_clock_base *base;
1154 : : unsigned long flags;
1155 : : int ret = -1;
1156 : :
1157 : : /*
1158 : : * Check lockless first. If the timer is not active (neither
1159 : : * enqueued nor running the callback, nothing to do here. The
1160 : : * base lock does not serialize against a concurrent enqueue,
1161 : : * so we can avoid taking it.
1162 : : */
1163 [ + + ]: 2317194 : if (!hrtimer_active(timer))
1164 : : return 0;
1165 : :
1166 : 1444735 : base = lock_hrtimer_base(timer, &flags);
1167 : :
1168 [ + + ]: 1445233 : if (!hrtimer_callback_running(timer))
1169 : 1444769 : ret = remove_hrtimer(timer, base, false);
1170 : :
1171 : : unlock_hrtimer_base(timer, &flags);
1172 : :
1173 : 1445282 : return ret;
1174 : :
1175 : : }
1176 : : EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1177 : :
1178 : : #ifdef CONFIG_PREEMPT_RT
1179 : : static void hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base)
1180 : : {
1181 : : spin_lock_init(&base->softirq_expiry_lock);
1182 : : }
1183 : :
1184 : : static void hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base)
1185 : : {
1186 : : spin_lock(&base->softirq_expiry_lock);
1187 : : }
1188 : :
1189 : : static void hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base)
1190 : : {
1191 : : spin_unlock(&base->softirq_expiry_lock);
1192 : : }
1193 : :
1194 : : /*
1195 : : * The counterpart to hrtimer_cancel_wait_running().
1196 : : *
1197 : : * If there is a waiter for cpu_base->expiry_lock, then it was waiting for
1198 : : * the timer callback to finish. Drop expiry_lock and reaquire it. That
1199 : : * allows the waiter to acquire the lock and make progress.
1200 : : */
1201 : : static void hrtimer_sync_wait_running(struct hrtimer_cpu_base *cpu_base,
1202 : : unsigned long flags)
1203 : : {
1204 : : if (atomic_read(&cpu_base->timer_waiters)) {
1205 : : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1206 : : spin_unlock(&cpu_base->softirq_expiry_lock);
1207 : : spin_lock(&cpu_base->softirq_expiry_lock);
1208 : : raw_spin_lock_irq(&cpu_base->lock);
1209 : : }
1210 : : }
1211 : :
1212 : : /*
1213 : : * This function is called on PREEMPT_RT kernels when the fast path
1214 : : * deletion of a timer failed because the timer callback function was
1215 : : * running.
1216 : : *
1217 : : * This prevents priority inversion: if the soft irq thread is preempted
1218 : : * in the middle of a timer callback, then calling del_timer_sync() can
1219 : : * lead to two issues:
1220 : : *
1221 : : * - If the caller is on a remote CPU then it has to spin wait for the timer
1222 : : * handler to complete. This can result in unbound priority inversion.
1223 : : *
1224 : : * - If the caller originates from the task which preempted the timer
1225 : : * handler on the same CPU, then spin waiting for the timer handler to
1226 : : * complete is never going to end.
1227 : : */
1228 : : void hrtimer_cancel_wait_running(const struct hrtimer *timer)
1229 : : {
1230 : : /* Lockless read. Prevent the compiler from reloading it below */
1231 : : struct hrtimer_clock_base *base = READ_ONCE(timer->base);
1232 : :
1233 : : /*
1234 : : * Just relax if the timer expires in hard interrupt context or if
1235 : : * it is currently on the migration base.
1236 : : */
1237 : : if (!timer->is_soft || is_migration_base(base)) {
1238 : : cpu_relax();
1239 : : return;
1240 : : }
1241 : :
1242 : : /*
1243 : : * Mark the base as contended and grab the expiry lock, which is
1244 : : * held by the softirq across the timer callback. Drop the lock
1245 : : * immediately so the softirq can expire the next timer. In theory
1246 : : * the timer could already be running again, but that's more than
1247 : : * unlikely and just causes another wait loop.
1248 : : */
1249 : : atomic_inc(&base->cpu_base->timer_waiters);
1250 : : spin_lock_bh(&base->cpu_base->softirq_expiry_lock);
1251 : : atomic_dec(&base->cpu_base->timer_waiters);
1252 : : spin_unlock_bh(&base->cpu_base->softirq_expiry_lock);
1253 : : }
1254 : : #else
1255 : : static inline void
1256 : : hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base) { }
1257 : : static inline void
1258 : : hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base) { }
1259 : : static inline void
1260 : : hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base) { }
1261 : : static inline void hrtimer_sync_wait_running(struct hrtimer_cpu_base *base,
1262 : : unsigned long flags) { }
1263 : : #endif
1264 : :
1265 : : /**
1266 : : * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1267 : : * @timer: the timer to be cancelled
1268 : : *
1269 : : * Returns:
1270 : : * 0 when the timer was not active
1271 : : * 1 when the timer was active
1272 : : */
1273 : 1160676 : int hrtimer_cancel(struct hrtimer *timer)
1274 : : {
1275 : : int ret;
1276 : :
1277 : : do {
1278 : 1793267 : ret = hrtimer_try_to_cancel(timer);
1279 : :
1280 [ + + - + : 1792966 : if (ret < 0)
- + ]
1281 : : hrtimer_cancel_wait_running(timer);
1282 [ + + - + : 1793528 : } while (ret < 0);
- + ]
1283 : 1160832 : return ret;
1284 : : }
1285 : : EXPORT_SYMBOL_GPL(hrtimer_cancel);
1286 : :
1287 : : /**
1288 : : * hrtimer_get_remaining - get remaining time for the timer
1289 : : * @timer: the timer to read
1290 : : * @adjust: adjust relative timers when CONFIG_TIME_LOW_RES=y
1291 : : */
1292 : 42537 : ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
1293 : : {
1294 : : unsigned long flags;
1295 : : ktime_t rem;
1296 : :
1297 : 42537 : lock_hrtimer_base(timer, &flags);
1298 : : if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
1299 : : rem = hrtimer_expires_remaining_adjusted(timer);
1300 : : else
1301 : : rem = hrtimer_expires_remaining(timer);
1302 : : unlock_hrtimer_base(timer, &flags);
1303 : :
1304 : 42543 : return rem;
1305 : : }
1306 : : EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
1307 : :
1308 : : #ifdef CONFIG_NO_HZ_COMMON
1309 : : /**
1310 : : * hrtimer_get_next_event - get the time until next expiry event
1311 : : *
1312 : : * Returns the next expiry time or KTIME_MAX if no timer is pending.
1313 : : */
1314 : 96109754 : u64 hrtimer_get_next_event(void)
1315 : : {
1316 : 192219508 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1317 : : u64 expires = KTIME_MAX;
1318 : : unsigned long flags;
1319 : :
1320 : 96109754 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1321 : :
1322 [ - + ]: 96110489 : if (!__hrtimer_hres_active(cpu_base))
1323 : 0 : expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
1324 : :
1325 : 96110489 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1326 : :
1327 : 96110104 : return expires;
1328 : : }
1329 : :
1330 : : /**
1331 : : * hrtimer_next_event_without - time until next expiry event w/o one timer
1332 : : * @exclude: timer to exclude
1333 : : *
1334 : : * Returns the next expiry time over all timers except for the @exclude one or
1335 : : * KTIME_MAX if none of them is pending.
1336 : : */
1337 : 0 : u64 hrtimer_next_event_without(const struct hrtimer *exclude)
1338 : : {
1339 : 0 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1340 : : u64 expires = KTIME_MAX;
1341 : : unsigned long flags;
1342 : :
1343 : 0 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1344 : :
1345 [ # # ]: 0 : if (__hrtimer_hres_active(cpu_base)) {
1346 : : unsigned int active;
1347 : :
1348 [ # # ]: 0 : if (!cpu_base->softirq_activated) {
1349 : 0 : active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
1350 : 0 : expires = __hrtimer_next_event_base(cpu_base, exclude,
1351 : : active, KTIME_MAX);
1352 : : }
1353 : 0 : active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
1354 : 0 : expires = __hrtimer_next_event_base(cpu_base, exclude, active,
1355 : : expires);
1356 : : }
1357 : :
1358 : 0 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1359 : :
1360 : 0 : return expires;
1361 : : }
1362 : : #endif
1363 : :
1364 : 1587068 : static inline int hrtimer_clockid_to_base(clockid_t clock_id)
1365 : : {
1366 [ + + ]: 1587068 : if (likely(clock_id < MAX_CLOCKS)) {
1367 : 1586689 : int base = hrtimer_clock_to_base_table[clock_id];
1368 : :
1369 [ - + ]: 1586689 : if (likely(base != HRTIMER_MAX_CLOCK_BASES))
1370 : : return base;
1371 : : }
1372 : 380 : WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
1373 : 0 : return HRTIMER_BASE_MONOTONIC;
1374 : : }
1375 : :
1376 : 1587145 : static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1377 : : enum hrtimer_mode mode)
1378 : : {
1379 : 1587145 : bool softtimer = !!(mode & HRTIMER_MODE_SOFT);
1380 : : struct hrtimer_cpu_base *cpu_base;
1381 : : int base;
1382 : :
1383 : : /*
1384 : : * On PREEMPT_RT enabled kernels hrtimers which are not explicitely
1385 : : * marked for hard interrupt expiry mode are moved into soft
1386 : : * interrupt context for latency reasons and because the callbacks
1387 : : * can invoke functions which might sleep on RT, e.g. spin_lock().
1388 : : */
1389 : : if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(mode & HRTIMER_MODE_HARD))
1390 : : softtimer = true;
1391 : :
1392 : 1587145 : memset(timer, 0, sizeof(struct hrtimer));
1393 : :
1394 : 3174290 : cpu_base = raw_cpu_ptr(&hrtimer_bases);
1395 : :
1396 : : /*
1397 : : * POSIX magic: Relative CLOCK_REALTIME timers are not affected by
1398 : : * clock modifications, so they needs to become CLOCK_MONOTONIC to
1399 : : * ensure POSIX compliance.
1400 : : */
1401 [ + + + + ]: 1587145 : if (clock_id == CLOCK_REALTIME && mode & HRTIMER_MODE_REL)
1402 : : clock_id = CLOCK_MONOTONIC;
1403 : :
1404 [ + + ]: 1587145 : base = softtimer ? HRTIMER_MAX_CLOCK_BASES / 2 : 0;
1405 : 1587145 : base += hrtimer_clockid_to_base(clock_id);
1406 : 1587004 : timer->is_soft = softtimer;
1407 : 1587004 : timer->is_hard = !softtimer;
1408 : 1587004 : timer->base = &cpu_base->clock_base[base];
1409 : : timerqueue_init(&timer->node);
1410 : 1587004 : }
1411 : :
1412 : : /**
1413 : : * hrtimer_init - initialize a timer to the given clock
1414 : : * @timer: the timer to be initialized
1415 : : * @clock_id: the clock to be used
1416 : : * @mode: The modes which are relevant for intitialization:
1417 : : * HRTIMER_MODE_ABS, HRTIMER_MODE_REL, HRTIMER_MODE_ABS_SOFT,
1418 : : * HRTIMER_MODE_REL_SOFT
1419 : : *
1420 : : * The PINNED variants of the above can be handed in,
1421 : : * but the PINNED bit is ignored as pinning happens
1422 : : * when the hrtimer is started
1423 : : */
1424 : 939374 : void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1425 : : enum hrtimer_mode mode)
1426 : : {
1427 : : debug_init(timer, clock_id, mode);
1428 : 939397 : __hrtimer_init(timer, clock_id, mode);
1429 : 939716 : }
1430 : : EXPORT_SYMBOL_GPL(hrtimer_init);
1431 : :
1432 : : /*
1433 : : * A timer is active, when it is enqueued into the rbtree or the
1434 : : * callback function is running or it's in the state of being migrated
1435 : : * to another cpu.
1436 : : *
1437 : : * It is important for this function to not return a false negative.
1438 : : */
1439 : 5197817 : bool hrtimer_active(const struct hrtimer *timer)
1440 : : {
1441 : : struct hrtimer_clock_base *base;
1442 : : unsigned int seq;
1443 : :
1444 : : do {
1445 : 5203837 : base = READ_ONCE(timer->base);
1446 : : seq = raw_read_seqcount_begin(&base->seq);
1447 : :
1448 [ + + + - ]: 8912598 : if (timer->state != HRTIMER_STATE_INACTIVE ||
1449 : 3736476 : base->running == timer)
1450 : : return true;
1451 : :
1452 [ + + ]: 4041933 : } while (read_seqcount_retry(&base->seq, seq) ||
1453 [ - + ]: 7775271 : base != READ_ONCE(timer->base));
1454 : :
1455 : : return false;
1456 : : }
1457 : : EXPORT_SYMBOL_GPL(hrtimer_active);
1458 : :
1459 : : /*
1460 : : * The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
1461 : : * distinct sections:
1462 : : *
1463 : : * - queued: the timer is queued
1464 : : * - callback: the timer is being ran
1465 : : * - post: the timer is inactive or (re)queued
1466 : : *
1467 : : * On the read side we ensure we observe timer->state and cpu_base->running
1468 : : * from the same section, if anything changed while we looked at it, we retry.
1469 : : * This includes timer->base changing because sequence numbers alone are
1470 : : * insufficient for that.
1471 : : *
1472 : : * The sequence numbers are required because otherwise we could still observe
1473 : : * a false negative if the read side got smeared over multiple consequtive
1474 : : * __run_hrtimer() invocations.
1475 : : */
1476 : :
1477 : 1898067 : static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
1478 : : struct hrtimer_clock_base *base,
1479 : : struct hrtimer *timer, ktime_t *now,
1480 : : unsigned long flags)
1481 : : {
1482 : : enum hrtimer_restart (*fn)(struct hrtimer *);
1483 : : int restart;
1484 : :
1485 : : lockdep_assert_held(&cpu_base->lock);
1486 : :
1487 : : debug_deactivate(timer);
1488 : 2953438 : base->running = timer;
1489 : :
1490 : : /*
1491 : : * Separate the ->running assignment from the ->state assignment.
1492 : : *
1493 : : * As with a regular write barrier, this ensures the read side in
1494 : : * hrtimer_active() cannot observe base->running == NULL &&
1495 : : * timer->state == INACTIVE.
1496 : : */
1497 : : raw_write_seqcount_barrier(&base->seq);
1498 : :
1499 : 2188648 : __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
1500 : 2237193 : fn = timer->function;
1501 : :
1502 : : /*
1503 : : * Clear the 'is relative' flag for the TIME_LOW_RES case. If the
1504 : : * timer is restarted with a period then it becomes an absolute
1505 : : * timer. If its not restarted it does not matter.
1506 : : */
1507 : : if (IS_ENABLED(CONFIG_TIME_LOW_RES))
1508 : : timer->is_rel = false;
1509 : :
1510 : : /*
1511 : : * The timer is marked as running in the CPU base, so it is
1512 : : * protected against migration to a different CPU even if the lock
1513 : : * is dropped.
1514 : : */
1515 : 2237193 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1516 : 2783312 : trace_hrtimer_expire_entry(timer, now);
1517 : 3018556 : restart = fn(timer);
1518 : 2940636 : trace_hrtimer_expire_exit(timer);
1519 : 2599610 : raw_spin_lock_irq(&cpu_base->lock);
1520 : :
1521 : : /*
1522 : : * Note: We clear the running state after enqueue_hrtimer and
1523 : : * we do not reprogram the event hardware. Happens either in
1524 : : * hrtimer_start_range_ns() or in hrtimer_interrupt()
1525 : : *
1526 : : * Note: Because we dropped the cpu_base->lock above,
1527 : : * hrtimer_start_range_ns() can have popped in and enqueued the timer
1528 : : * for us already.
1529 : : */
1530 [ + + + + ]: 5922114 : if (restart != HRTIMER_NORESTART &&
1531 : 2792626 : !(timer->state & HRTIMER_STATE_ENQUEUED))
1532 : 2773540 : enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS);
1533 : :
1534 : : /*
1535 : : * Separate the ->running assignment from the ->state assignment.
1536 : : *
1537 : : * As with a regular write barrier, this ensures the read side in
1538 : : * hrtimer_active() cannot observe base->running.timer == NULL &&
1539 : : * timer->state == INACTIVE.
1540 : : */
1541 : : raw_write_seqcount_barrier(&base->seq);
1542 : :
1543 [ - + # # ]: 2539694 : WARN_ON_ONCE(base->running != timer);
1544 : 2539694 : base->running = NULL;
1545 : 2539694 : }
1546 : :
1547 : 2308869 : static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now,
1548 : : unsigned long flags, unsigned int active_mask)
1549 : : {
1550 : : struct hrtimer_clock_base *base;
1551 : 2308869 : unsigned int active = cpu_base->active_bases & active_mask;
1552 : :
1553 [ + + ]: 9312790 : for_each_active_base(base, cpu_base, active) {
1554 : : struct timerqueue_node *node;
1555 : : ktime_t basenow;
1556 : :
1557 : 3854372 : basenow = ktime_add(now, base->offset);
1558 : :
1559 [ + + ]: 10450176 : while ((node = timerqueue_getnext(&base->active))) {
1560 : : struct hrtimer *timer;
1561 : :
1562 : : timer = container_of(node, struct hrtimer, node);
1563 : :
1564 : : /*
1565 : : * The immediate goal for using the softexpires is
1566 : : * minimizing wakeups, not running timers at the
1567 : : * earliest interrupt after their soft expiration.
1568 : : * This allows us to avoid using a Priority Search
1569 : : * Tree, which can answer a stabbing querry for
1570 : : * overlapping intervals and instead use the simple
1571 : : * BST we already have.
1572 : : * We don't add extra wakeups by delaying timers that
1573 : : * are right-of a not yet expired timer, because that
1574 : : * timer will have to trigger a wakeup anyway.
1575 : : */
1576 [ + + ]: 6606792 : if (basenow < hrtimer_get_softexpires_tv64(timer))
1577 : : break;
1578 : :
1579 : 1900752 : __run_hrtimer(cpu_base, base, timer, &basenow, flags);
1580 : : if (active_mask == HRTIMER_ACTIVE_SOFT)
1581 : : hrtimer_sync_wait_running(cpu_base, flags);
1582 : : }
1583 : : }
1584 : 3149549 : }
1585 : :
1586 : 0 : static __latent_entropy void hrtimer_run_softirq(struct softirq_action *h)
1587 : : {
1588 : 0 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1589 : : unsigned long flags;
1590 : : ktime_t now;
1591 : :
1592 : : hrtimer_cpu_base_lock_expiry(cpu_base);
1593 : 0 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1594 : :
1595 : 0 : now = hrtimer_update_base(cpu_base);
1596 : 0 : __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_SOFT);
1597 : :
1598 : 0 : cpu_base->softirq_activated = 0;
1599 : 0 : hrtimer_update_softirq_timer(cpu_base, true);
1600 : :
1601 : 0 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1602 : : hrtimer_cpu_base_unlock_expiry(cpu_base);
1603 : 0 : }
1604 : :
1605 : : #ifdef CONFIG_HIGH_RES_TIMERS
1606 : :
1607 : : /*
1608 : : * High resolution timer interrupt
1609 : : * Called with interrupts disabled
1610 : : */
1611 : 2667825 : void hrtimer_interrupt(struct clock_event_device *dev)
1612 : : {
1613 : 5335650 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1614 : : ktime_t expires_next, now, entry_time, delta;
1615 : : unsigned long flags;
1616 : : int retries = 0;
1617 : :
1618 [ - + ]: 2667825 : BUG_ON(!cpu_base->hres_active);
1619 : 2667825 : cpu_base->nr_events++;
1620 : 2667825 : dev->next_event = KTIME_MAX;
1621 : :
1622 : 2667825 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1623 : 2955043 : entry_time = now = hrtimer_update_base(cpu_base);
1624 : : retry:
1625 : 3224878 : cpu_base->in_hrtirq = 1;
1626 : : /*
1627 : : * We set expires_next to KTIME_MAX here with cpu_base->lock
1628 : : * held to prevent that a timer is enqueued in our queue via
1629 : : * the migration code. This does not affect enqueueing of
1630 : : * timers which run their callback and need to be requeued on
1631 : : * this CPU.
1632 : : */
1633 : 3224878 : cpu_base->expires_next = KTIME_MAX;
1634 : :
1635 [ - + ]: 6449756 : if (!ktime_before(now, cpu_base->softirq_expires_next)) {
1636 : 0 : cpu_base->softirq_expires_next = KTIME_MAX;
1637 : 0 : cpu_base->softirq_activated = 1;
1638 : 0 : raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1639 : : }
1640 : :
1641 : 3224878 : __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
1642 : :
1643 : : /* Reevaluate the clock bases for the next expiry */
1644 : 3239762 : expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
1645 : : /*
1646 : : * Store the new expiry value so the migration code can verify
1647 : : * against it.
1648 : : */
1649 : 3194760 : cpu_base->expires_next = expires_next;
1650 : 3194760 : cpu_base->in_hrtirq = 0;
1651 : 3194760 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1652 : :
1653 : : /* Reprogramming necessary ? */
1654 [ + + ]: 3238915 : if (!tick_program_event(expires_next, 0)) {
1655 : 2670710 : cpu_base->hang_detected = 0;
1656 : 5341420 : return;
1657 : : }
1658 : :
1659 : : /*
1660 : : * The next timer was already expired due to:
1661 : : * - tracing
1662 : : * - long lasting callbacks
1663 : : * - being scheduled away when running in a VM
1664 : : *
1665 : : * We need to prevent that we loop forever in the hrtimer
1666 : : * interrupt routine. We give it 3 attempts to avoid
1667 : : * overreacting on some spurious event.
1668 : : *
1669 : : * Acquire base lock for updating the offsets and retrieving
1670 : : * the current time.
1671 : : */
1672 : 1497 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1673 : 1553 : now = hrtimer_update_base(cpu_base);
1674 : 1476 : cpu_base->nr_retries++;
1675 [ + - ]: 1476 : if (++retries < 3)
1676 : : goto retry;
1677 : : /*
1678 : : * Give the system a chance to do something else than looping
1679 : : * here. We stored the entry time, so we know exactly how long
1680 : : * we spent here. We schedule the next event this amount of
1681 : : * time away.
1682 : : */
1683 : 0 : cpu_base->nr_hangs++;
1684 : 0 : cpu_base->hang_detected = 1;
1685 : 0 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1686 : :
1687 : 0 : delta = ktime_sub(now, entry_time);
1688 [ # # ]: 0 : if ((unsigned int)delta > cpu_base->max_hang_time)
1689 : 0 : cpu_base->max_hang_time = (unsigned int) delta;
1690 : : /*
1691 : : * Limit it to a sensible value as we enforce a longer
1692 : : * delay. Give the CPU at least 100ms to catch up.
1693 : : */
1694 [ # # ]: 0 : if (delta > 100 * NSEC_PER_MSEC)
1695 : 0 : expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1696 : : else
1697 : 0 : expires_next = ktime_add(now, delta);
1698 : 0 : tick_program_event(expires_next, 1);
1699 [ # # ]: 0 : pr_warn_once("hrtimer: interrupt took %llu ns\n", ktime_to_ns(delta));
1700 : : }
1701 : :
1702 : : /* called with interrupts disabled */
1703 : : static inline void __hrtimer_peek_ahead_timers(void)
1704 : : {
1705 : : struct tick_device *td;
1706 : :
1707 : : if (!hrtimer_hres_active())
1708 : : return;
1709 : :
1710 : : td = this_cpu_ptr(&tick_cpu_device);
1711 : : if (td && td->evtdev)
1712 : : hrtimer_interrupt(td->evtdev);
1713 : : }
1714 : :
1715 : : #else /* CONFIG_HIGH_RES_TIMERS */
1716 : :
1717 : : static inline void __hrtimer_peek_ahead_timers(void) { }
1718 : :
1719 : : #endif /* !CONFIG_HIGH_RES_TIMERS */
1720 : :
1721 : : /*
1722 : : * Called from run_local_timers in hardirq context every jiffy
1723 : : */
1724 : 2808776 : void hrtimer_run_queues(void)
1725 : : {
1726 : 5617552 : struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1727 : : unsigned long flags;
1728 : : ktime_t now;
1729 : :
1730 [ + + ]: 2808776 : if (__hrtimer_hres_active(cpu_base))
1731 : : return;
1732 : :
1733 : : /*
1734 : : * This _is_ ugly: We have to check periodically, whether we
1735 : : * can switch to highres and / or nohz mode. The clocksource
1736 : : * switch happens with xtime_lock held. Notification from
1737 : : * there only sets the check bit in the tick_oneshot code,
1738 : : * otherwise we might deadlock vs. xtime_lock.
1739 : : */
1740 [ + + ]: 22977 : if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
1741 : 828 : hrtimer_switch_to_hres();
1742 : 828 : return;
1743 : : }
1744 : :
1745 : 22149 : raw_spin_lock_irqsave(&cpu_base->lock, flags);
1746 : 22149 : now = hrtimer_update_base(cpu_base);
1747 : :
1748 [ - + ]: 44298 : if (!ktime_before(now, cpu_base->softirq_expires_next)) {
1749 : 0 : cpu_base->softirq_expires_next = KTIME_MAX;
1750 : 0 : cpu_base->softirq_activated = 1;
1751 : 0 : raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1752 : : }
1753 : :
1754 : 22149 : __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
1755 : 22149 : raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1756 : : }
1757 : :
1758 : : /*
1759 : : * Sleep related functions:
1760 : : */
1761 : 184015 : static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1762 : : {
1763 : : struct hrtimer_sleeper *t =
1764 : : container_of(timer, struct hrtimer_sleeper, timer);
1765 : 184015 : struct task_struct *task = t->task;
1766 : :
1767 : 184015 : t->task = NULL;
1768 [ + + ]: 184015 : if (task)
1769 : 184014 : wake_up_process(task);
1770 : :
1771 : 184016 : return HRTIMER_NORESTART;
1772 : : }
1773 : :
1774 : : /**
1775 : : * hrtimer_sleeper_start_expires - Start a hrtimer sleeper timer
1776 : : * @sl: sleeper to be started
1777 : : * @mode: timer mode abs/rel
1778 : : *
1779 : : * Wrapper around hrtimer_start_expires() for hrtimer_sleeper based timers
1780 : : * to allow PREEMPT_RT to tweak the delivery mode (soft/hardirq context)
1781 : : */
1782 : 11796 : void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
1783 : : enum hrtimer_mode mode)
1784 : : {
1785 : : /*
1786 : : * Make the enqueue delivery mode check work on RT. If the sleeper
1787 : : * was initialized for hard interrupt delivery, force the mode bit.
1788 : : * This is a special case for hrtimer_sleepers because
1789 : : * hrtimer_init_sleeper() determines the delivery mode on RT so the
1790 : : * fiddling with this decision is avoided at the call sites.
1791 : : */
1792 : : if (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)
1793 : : mode |= HRTIMER_MODE_HARD;
1794 : :
1795 : 647377 : hrtimer_start_expires(&sl->timer, mode);
1796 : 11799 : }
1797 : : EXPORT_SYMBOL_GPL(hrtimer_sleeper_start_expires);
1798 : :
1799 : : static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
1800 : : clockid_t clock_id, enum hrtimer_mode mode)
1801 : : {
1802 : : /*
1803 : : * On PREEMPT_RT enabled kernels hrtimers which are not explicitely
1804 : : * marked for hard interrupt expiry mode are moved into soft
1805 : : * interrupt context either for latency reasons or because the
1806 : : * hrtimer callback takes regular spinlocks or invokes other
1807 : : * functions which are not suitable for hard interrupt context on
1808 : : * PREEMPT_RT.
1809 : : *
1810 : : * The hrtimer_sleeper callback is RT compatible in hard interrupt
1811 : : * context, but there is a latency concern: Untrusted userspace can
1812 : : * spawn many threads which arm timers for the same expiry time on
1813 : : * the same CPU. That causes a latency spike due to the wakeup of
1814 : : * a gazillion threads.
1815 : : *
1816 : : * OTOH, priviledged real-time user space applications rely on the
1817 : : * low latency of hard interrupt wakeups. If the current task is in
1818 : : * a real-time scheduling class, mark the mode for hard interrupt
1819 : : * expiry.
1820 : : */
1821 : : if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1822 : : if (task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT))
1823 : : mode |= HRTIMER_MODE_HARD;
1824 : : }
1825 : :
1826 : 647360 : __hrtimer_init(&sl->timer, clock_id, mode);
1827 : 647402 : sl->timer.function = hrtimer_wakeup;
1828 : 647402 : sl->task = current;
1829 : : }
1830 : :
1831 : : /**
1832 : : * hrtimer_init_sleeper - initialize sleeper to the given clock
1833 : : * @sl: sleeper to be initialized
1834 : : * @clock_id: the clock to be used
1835 : : * @mode: timer mode abs/rel
1836 : : */
1837 : 647346 : void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
1838 : : enum hrtimer_mode mode)
1839 : : {
1840 : 647346 : debug_init(&sl->timer, clock_id, mode);
1841 : : __hrtimer_init_sleeper(sl, clock_id, mode);
1842 : :
1843 : 647402 : }
1844 : : EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1845 : :
1846 : 6 : int nanosleep_copyout(struct restart_block *restart, struct timespec64 *ts)
1847 : : {
1848 [ + - - ]: 6 : switch(restart->nanosleep.type) {
1849 : : #ifdef CONFIG_COMPAT_32BIT_TIME
1850 : : case TT_COMPAT:
1851 [ + - ]: 6 : if (put_old_timespec32(ts, restart->nanosleep.compat_rmtp))
1852 : : return -EFAULT;
1853 : : break;
1854 : : #endif
1855 : : case TT_NATIVE:
1856 [ # # ]: 0 : if (put_timespec64(ts, restart->nanosleep.rmtp))
1857 : : return -EFAULT;
1858 : : break;
1859 : : default:
1860 : 0 : BUG();
1861 : : }
1862 : : return -ERESTART_RESTARTBLOCK;
1863 : : }
1864 : :
1865 : 1178 : static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1866 : : {
1867 : : struct restart_block *restart;
1868 : :
1869 : : do {
1870 : 3534 : set_current_state(TASK_INTERRUPTIBLE);
1871 : : hrtimer_sleeper_start_expires(t, mode);
1872 : :
1873 [ + - ]: 1178 : if (likely(t->task))
1874 : 1178 : freezable_schedule();
1875 : :
1876 : : hrtimer_cancel(&t->timer);
1877 : : mode = HRTIMER_MODE_ABS;
1878 : :
1879 [ + + - + ]: 776 : } while (t->task && !signal_pending(current));
1880 : :
1881 : 764 : __set_current_state(TASK_RUNNING);
1882 : :
1883 [ + + ]: 764 : if (!t->task)
1884 : : return 0;
1885 : :
1886 : 6 : restart = ¤t->restart_block;
1887 [ + - ]: 6 : if (restart->nanosleep.type != TT_NONE) {
1888 : : ktime_t rem = hrtimer_expires_remaining(&t->timer);
1889 : : struct timespec64 rmt;
1890 : :
1891 [ + - ]: 6 : if (rem <= 0)
1892 : : return 0;
1893 : 6 : rmt = ktime_to_timespec64(rem);
1894 : :
1895 : 6 : return nanosleep_copyout(restart, &rmt);
1896 : : }
1897 : : return -ERESTART_RESTARTBLOCK;
1898 : : }
1899 : :
1900 : 0 : static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1901 : : {
1902 : : struct hrtimer_sleeper t;
1903 : : int ret;
1904 : :
1905 : 0 : hrtimer_init_sleeper_on_stack(&t, restart->nanosleep.clockid,
1906 : : HRTIMER_MODE_ABS);
1907 : 0 : hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1908 : 0 : ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
1909 : : destroy_hrtimer_on_stack(&t.timer);
1910 : 0 : return ret;
1911 : : }
1912 : :
1913 : 1178 : long hrtimer_nanosleep(const struct timespec64 *rqtp,
1914 : : const enum hrtimer_mode mode, const clockid_t clockid)
1915 : : {
1916 : : struct restart_block *restart;
1917 : : struct hrtimer_sleeper t;
1918 : : int ret = 0;
1919 : : u64 slack;
1920 : :
1921 : 1178 : slack = current->timer_slack_ns;
1922 [ + - - + ]: 2356 : if (dl_task(current) || rt_task(current))
1923 : : slack = 0;
1924 : :
1925 : : hrtimer_init_sleeper_on_stack(&t, clockid, mode);
1926 : : hrtimer_set_expires_range_ns(&t.timer, timespec64_to_ktime(*rqtp), slack);
1927 : 1178 : ret = do_nanosleep(&t, mode);
1928 [ + + ]: 764 : if (ret != -ERESTART_RESTARTBLOCK)
1929 : : goto out;
1930 : :
1931 : : /* Absolute timers do not update the rmtp value and restart: */
1932 [ + - ]: 6 : if (mode == HRTIMER_MODE_ABS) {
1933 : : ret = -ERESTARTNOHAND;
1934 : : goto out;
1935 : : }
1936 : :
1937 : 6 : restart = ¤t->restart_block;
1938 : 6 : restart->fn = hrtimer_nanosleep_restart;
1939 : 6 : restart->nanosleep.clockid = t.timer.base->clockid;
1940 : 6 : restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1941 : : out:
1942 : : destroy_hrtimer_on_stack(&t.timer);
1943 : 764 : return ret;
1944 : : }
1945 : :
1946 : : #if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT)
1947 : :
1948 : : SYSCALL_DEFINE2(nanosleep, struct __kernel_timespec __user *, rqtp,
1949 : : struct __kernel_timespec __user *, rmtp)
1950 : : {
1951 : : struct timespec64 tu;
1952 : :
1953 : : if (get_timespec64(&tu, rqtp))
1954 : : return -EFAULT;
1955 : :
1956 : : if (!timespec64_valid(&tu))
1957 : : return -EINVAL;
1958 : :
1959 : : current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
1960 : : current->restart_block.nanosleep.rmtp = rmtp;
1961 : : return hrtimer_nanosleep(&tu, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1962 : : }
1963 : :
1964 : : #endif
1965 : :
1966 : : #ifdef CONFIG_COMPAT_32BIT_TIME
1967 : :
1968 : 2356 : SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp,
1969 : : struct old_timespec32 __user *, rmtp)
1970 : : {
1971 : : struct timespec64 tu;
1972 : :
1973 [ + - ]: 1178 : if (get_old_timespec32(&tu, rqtp))
1974 : : return -EFAULT;
1975 : :
1976 [ + - ]: 1178 : if (!timespec64_valid(&tu))
1977 : : return -EINVAL;
1978 : :
1979 [ + + ]: 1178 : current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
1980 : 1178 : current->restart_block.nanosleep.compat_rmtp = rmtp;
1981 : 1178 : return hrtimer_nanosleep(&tu, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1982 : : }
1983 : : #endif
1984 : :
1985 : : /*
1986 : : * Functions related to boot-time initialization:
1987 : : */
1988 : 828 : int hrtimers_prepare_cpu(unsigned int cpu)
1989 : : {
1990 : 828 : struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1991 : : int i;
1992 : :
1993 [ + + ]: 7452 : for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1994 : 6624 : cpu_base->clock_base[i].cpu_base = cpu_base;
1995 : : timerqueue_init_head(&cpu_base->clock_base[i].active);
1996 : : }
1997 : :
1998 : 828 : cpu_base->cpu = cpu;
1999 : 828 : cpu_base->active_bases = 0;
2000 : 828 : cpu_base->hres_active = 0;
2001 : 828 : cpu_base->hang_detected = 0;
2002 : 828 : cpu_base->next_timer = NULL;
2003 : 828 : cpu_base->softirq_next_timer = NULL;
2004 : 828 : cpu_base->expires_next = KTIME_MAX;
2005 : 828 : cpu_base->softirq_expires_next = KTIME_MAX;
2006 : : hrtimer_cpu_base_init_expiry_lock(cpu_base);
2007 : 828 : return 0;
2008 : : }
2009 : :
2010 : : #ifdef CONFIG_HOTPLUG_CPU
2011 : :
2012 : : static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
2013 : : struct hrtimer_clock_base *new_base)
2014 : : {
2015 : : struct hrtimer *timer;
2016 : : struct timerqueue_node *node;
2017 : :
2018 : : while ((node = timerqueue_getnext(&old_base->active))) {
2019 : : timer = container_of(node, struct hrtimer, node);
2020 : : BUG_ON(hrtimer_callback_running(timer));
2021 : : debug_deactivate(timer);
2022 : :
2023 : : /*
2024 : : * Mark it as ENQUEUED not INACTIVE otherwise the
2025 : : * timer could be seen as !active and just vanish away
2026 : : * under us on another CPU
2027 : : */
2028 : : __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
2029 : : timer->base = new_base;
2030 : : /*
2031 : : * Enqueue the timers on the new cpu. This does not
2032 : : * reprogram the event device in case the timer
2033 : : * expires before the earliest on this CPU, but we run
2034 : : * hrtimer_interrupt after we migrated everything to
2035 : : * sort out already expired timers and reprogram the
2036 : : * event device.
2037 : : */
2038 : : enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);
2039 : : }
2040 : : }
2041 : :
2042 : : int hrtimers_dead_cpu(unsigned int scpu)
2043 : : {
2044 : : struct hrtimer_cpu_base *old_base, *new_base;
2045 : : int i;
2046 : :
2047 : : BUG_ON(cpu_online(scpu));
2048 : : tick_cancel_sched_timer(scpu);
2049 : :
2050 : : /*
2051 : : * this BH disable ensures that raise_softirq_irqoff() does
2052 : : * not wakeup ksoftirqd (and acquire the pi-lock) while
2053 : : * holding the cpu_base lock
2054 : : */
2055 : : local_bh_disable();
2056 : : local_irq_disable();
2057 : : old_base = &per_cpu(hrtimer_bases, scpu);
2058 : : new_base = this_cpu_ptr(&hrtimer_bases);
2059 : : /*
2060 : : * The caller is globally serialized and nobody else
2061 : : * takes two locks at once, deadlock is not possible.
2062 : : */
2063 : : raw_spin_lock(&new_base->lock);
2064 : : raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
2065 : :
2066 : : for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
2067 : : migrate_hrtimer_list(&old_base->clock_base[i],
2068 : : &new_base->clock_base[i]);
2069 : : }
2070 : :
2071 : : /*
2072 : : * The migration might have changed the first expiring softirq
2073 : : * timer on this CPU. Update it.
2074 : : */
2075 : : hrtimer_update_softirq_timer(new_base, false);
2076 : :
2077 : : raw_spin_unlock(&old_base->lock);
2078 : : raw_spin_unlock(&new_base->lock);
2079 : :
2080 : : /* Check, if we got expired work to do */
2081 : : __hrtimer_peek_ahead_timers();
2082 : : local_irq_enable();
2083 : : local_bh_enable();
2084 : : return 0;
2085 : : }
2086 : :
2087 : : #endif /* CONFIG_HOTPLUG_CPU */
2088 : :
2089 : 207 : void __init hrtimers_init(void)
2090 : : {
2091 : 207 : hrtimers_prepare_cpu(smp_processor_id());
2092 : 207 : open_softirq(HRTIMER_SOFTIRQ, hrtimer_run_softirq);
2093 : 207 : }
2094 : :
2095 : : /**
2096 : : * schedule_hrtimeout_range_clock - sleep until timeout
2097 : : * @expires: timeout value (ktime_t)
2098 : : * @delta: slack in expires timeout (ktime_t)
2099 : : * @mode: timer mode
2100 : : * @clock_id: timer clock to be used
2101 : : */
2102 : : int __sched
2103 : 1375361 : schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
2104 : : const enum hrtimer_mode mode, clockid_t clock_id)
2105 : : {
2106 : : struct hrtimer_sleeper t;
2107 : :
2108 : : /*
2109 : : * Optimize when a zero timeout value is given. It does not
2110 : : * matter whether this is an absolute or a relative time.
2111 : : */
2112 [ + + - + ]: 1375361 : if (expires && *expires == 0) {
2113 : 0 : __set_current_state(TASK_RUNNING);
2114 : 0 : return 0;
2115 : : }
2116 : :
2117 : : /*
2118 : : * A NULL parameter means "infinite"
2119 : : */
2120 [ + + ]: 1375361 : if (!expires) {
2121 : 740952 : schedule();
2122 : 727063 : return -EINTR;
2123 : : }
2124 : :
2125 : : hrtimer_init_sleeper_on_stack(&t, clock_id, mode);
2126 : 634403 : hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
2127 : : hrtimer_sleeper_start_expires(&t, mode);
2128 : :
2129 [ + + ]: 634433 : if (likely(t.task))
2130 : 631454 : schedule();
2131 : :
2132 : : hrtimer_cancel(&t.timer);
2133 : : destroy_hrtimer_on_stack(&t.timer);
2134 : :
2135 : 631930 : __set_current_state(TASK_RUNNING);
2136 : :
2137 [ + + ]: 631930 : return !t.task ? 0 : -EINTR;
2138 : : }
2139 : :
2140 : : /**
2141 : : * schedule_hrtimeout_range - sleep until timeout
2142 : : * @expires: timeout value (ktime_t)
2143 : : * @delta: slack in expires timeout (ktime_t)
2144 : : * @mode: timer mode
2145 : : *
2146 : : * Make the current task sleep until the given expiry time has
2147 : : * elapsed. The routine will return immediately unless
2148 : : * the current task state has been set (see set_current_state()).
2149 : : *
2150 : : * The @delta argument gives the kernel the freedom to schedule the
2151 : : * actual wakeup to a time that is both power and performance friendly.
2152 : : * The kernel give the normal best effort behavior for "@expires+@delta",
2153 : : * but may decide to fire the timer earlier, but no earlier than @expires.
2154 : : *
2155 : : * You can set the task state as follows -
2156 : : *
2157 : : * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
2158 : : * pass before the routine returns unless the current task is explicitly
2159 : : * woken up, (e.g. by wake_up_process()).
2160 : : *
2161 : : * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
2162 : : * delivered to the current task or the current task is explicitly woken
2163 : : * up.
2164 : : *
2165 : : * The current task state is guaranteed to be TASK_RUNNING when this
2166 : : * routine returns.
2167 : : *
2168 : : * Returns 0 when the timer has expired. If the task was woken before the
2169 : : * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
2170 : : * by an explicit wakeup, it returns -EINTR.
2171 : : */
2172 : 1375171 : int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
2173 : : const enum hrtimer_mode mode)
2174 : : {
2175 : 1375171 : return schedule_hrtimeout_range_clock(expires, delta, mode,
2176 : : CLOCK_MONOTONIC);
2177 : : }
2178 : : EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
2179 : :
2180 : : /**
2181 : : * schedule_hrtimeout - sleep until timeout
2182 : : * @expires: timeout value (ktime_t)
2183 : : * @mode: timer mode
2184 : : *
2185 : : * Make the current task sleep until the given expiry time has
2186 : : * elapsed. The routine will return immediately unless
2187 : : * the current task state has been set (see set_current_state()).
2188 : : *
2189 : : * You can set the task state as follows -
2190 : : *
2191 : : * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
2192 : : * pass before the routine returns unless the current task is explicitly
2193 : : * woken up, (e.g. by wake_up_process()).
2194 : : *
2195 : : * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
2196 : : * delivered to the current task or the current task is explicitly woken
2197 : : * up.
2198 : : *
2199 : : * The current task state is guaranteed to be TASK_RUNNING when this
2200 : : * routine returns.
2201 : : *
2202 : : * Returns 0 when the timer has expired. If the task was woken before the
2203 : : * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
2204 : : * by an explicit wakeup, it returns -EINTR.
2205 : : */
2206 : 0 : int __sched schedule_hrtimeout(ktime_t *expires,
2207 : : const enum hrtimer_mode mode)
2208 : : {
2209 : 0 : return schedule_hrtimeout_range(expires, 0, mode);
2210 : : }
2211 : : EXPORT_SYMBOL_GPL(schedule_hrtimeout);
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