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1/*
2 * linux/kernel/hrtimer.c
3 *
4 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
6 * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
7 *
8 * High-resolution kernel timers
9 *
10 * In contrast to the low-resolution timeout API implemented in
11 * kernel/timer.c, hrtimers provide finer resolution and accuracy
12 * depending on system configuration and capabilities.
13 *
14 * These timers are currently used for:
15 * - itimers
16 * - POSIX timers
17 * - nanosleep
18 * - precise in-kernel timing
19 *
20 * Started by: Thomas Gleixner and Ingo Molnar
21 *
22 * Credits:
23 * based on kernel/timer.c
24 *
25 * Help, testing, suggestions, bugfixes, improvements were
26 * provided by:
27 *
28 * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
29 * et. al.
30 *
31 * For licencing details see kernel-base/COPYING
32 */
33
34#include <linux/cpu.h>
35#include <linux/export.h>
36#include <linux/percpu.h>
37#include <linux/hrtimer.h>
38#include <linux/notifier.h>
39#include <linux/syscalls.h>
40#include <linux/kallsyms.h>
41#include <linux/interrupt.h>
42#include <linux/tick.h>
43#include <linux/seq_file.h>
44#include <linux/err.h>
45#include <linux/debugobjects.h>
46#include <linux/sched.h>
47#include <linux/sched/sysctl.h>
48#include <linux/sched/rt.h>
49#include <linux/sched/deadline.h>
50#include <linux/timer.h>
51#include <linux/freezer.h>
52
53#include <asm/uaccess.h>
54
55#include <trace/events/timer.h>
56
57#include "tick-internal.h"
58
59/*
60 * The timer bases:
61 *
62 * There are more clockids than hrtimer bases. Thus, we index
63 * into the timer bases by the hrtimer_base_type enum. When trying
64 * to reach a base using a clockid, hrtimer_clockid_to_base()
65 * is used to convert from clockid to the proper hrtimer_base_type.
66 */
67DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
68{
69 .lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
70 .seq = SEQCNT_ZERO(hrtimer_bases.seq),
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};
95
96static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
97 [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
98 [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
99 [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
100 [CLOCK_TAI] = HRTIMER_BASE_TAI,
101};
102
103static inline int hrtimer_clockid_to_base(clockid_t clock_id)
104{
105 return hrtimer_clock_to_base_table[clock_id];
106}
107
108/*
109 * Functions and macros which are different for UP/SMP systems are kept in a
110 * single place
111 */
112#ifdef CONFIG_SMP
113
114/*
115 * We require the migration_base for lock_hrtimer_base()/switch_hrtimer_base()
116 * such that hrtimer_callback_running() can unconditionally dereference
117 * timer->base->cpu_base
118 */
119static struct hrtimer_cpu_base migration_cpu_base = {
120 .seq = SEQCNT_ZERO(migration_cpu_base),
121 .clock_base = { { .cpu_base = &migration_cpu_base, }, },
122};
123
124#define migration_base migration_cpu_base.clock_base[0]
125
126/*
127 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
128 * means that all timers which are tied to this base via timer->base are
129 * locked, and the base itself is locked too.
130 *
131 * So __run_timers/migrate_timers can safely modify all timers which could
132 * be found on the lists/queues.
133 *
134 * When the timer's base is locked, and the timer removed from list, it is
135 * possible to set timer->base = &migration_base and drop the lock: the timer
136 * remains locked.
137 */
138static
139struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
140 unsigned long *flags)
141{
142 struct hrtimer_clock_base *base;
143
144 for (;;) {
145 base = timer->base;
146 if (likely(base != &migration_base)) {
147 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
148 if (likely(base == timer->base))
149 return base;
150 /* The timer has migrated to another CPU: */
151 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
152 }
153 cpu_relax();
154 }
155}
156
157/*
158 * With HIGHRES=y we do not migrate the timer when it is expiring
159 * before the next event on the target cpu because we cannot reprogram
160 * the target cpu hardware and we would cause it to fire late.
161 *
162 * Called with cpu_base->lock of target cpu held.
163 */
164static int
165hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
166{
167#ifdef CONFIG_HIGH_RES_TIMERS
168 ktime_t expires;
169
170 if (!new_base->cpu_base->hres_active)
171 return 0;
172
173 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
174 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
175#else
176 return 0;
177#endif
178}
179
180#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
181static inline
182struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
183 int pinned)
184{
185 if (pinned || !base->migration_enabled)
186 return base;
187 return &per_cpu(hrtimer_bases, get_nohz_timer_target());
188}
189#else
190static inline
191struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
192 int pinned)
193{
194 return base;
195}
196#endif
197
198/*
199 * We switch the timer base to a power-optimized selected CPU target,
200 * if:
201 * - NO_HZ_COMMON is enabled
202 * - timer migration is enabled
203 * - the timer callback is not running
204 * - the timer is not the first expiring timer on the new target
205 *
206 * If one of the above requirements is not fulfilled we move the timer
207 * to the current CPU or leave it on the previously assigned CPU if
208 * the timer callback is currently running.
209 */
210static inline struct hrtimer_clock_base *
211switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
212 int pinned)
213{
214 struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
215 struct hrtimer_clock_base *new_base;
216 int basenum = base->index;
217
218 this_cpu_base = this_cpu_ptr(&hrtimer_bases);
219 new_cpu_base = get_target_base(this_cpu_base, pinned);
220again:
221 new_base = &new_cpu_base->clock_base[basenum];
222
223 if (base != new_base) {
224 /*
225 * We are trying to move timer to new_base.
226 * However we can't change timer's base while it is running,
227 * so we keep it on the same CPU. No hassle vs. reprogramming
228 * the event source in the high resolution case. The softirq
229 * code will take care of this when the timer function has
230 * completed. There is no conflict as we hold the lock until
231 * the timer is enqueued.
232 */
233 if (unlikely(hrtimer_callback_running(timer)))
234 return base;
235
236 /* See the comment in lock_hrtimer_base() */
237 timer->base = &migration_base;
238 raw_spin_unlock(&base->cpu_base->lock);
239 raw_spin_lock(&new_base->cpu_base->lock);
240
241 if (new_cpu_base != this_cpu_base &&
242 hrtimer_check_target(timer, new_base)) {
243 raw_spin_unlock(&new_base->cpu_base->lock);
244 raw_spin_lock(&base->cpu_base->lock);
245 new_cpu_base = this_cpu_base;
246 timer->base = base;
247 goto again;
248 }
249 timer->base = new_base;
250 } else {
251 if (new_cpu_base != this_cpu_base &&
252 hrtimer_check_target(timer, new_base)) {
253 new_cpu_base = this_cpu_base;
254 goto again;
255 }
256 }
257 return new_base;
258}
259
260#else /* CONFIG_SMP */
261
262static inline struct hrtimer_clock_base *
263lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
264{
265 struct hrtimer_clock_base *base = timer->base;
266
267 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
268
269 return base;
270}
271
272# define switch_hrtimer_base(t, b, p) (b)
273
274#endif /* !CONFIG_SMP */
275
276/*
277 * Functions for the union type storage format of ktime_t which are
278 * too large for inlining:
279 */
280#if BITS_PER_LONG < 64
281/*
282 * Divide a ktime value by a nanosecond value
283 */
284s64 __ktime_divns(const ktime_t kt, s64 div)
285{
286 int sft = 0;
287 s64 dclc;
288 u64 tmp;
289
290 dclc = ktime_to_ns(kt);
291 tmp = dclc < 0 ? -dclc : dclc;
292
293 /* Make sure the divisor is less than 2^32: */
294 while (div >> 32) {
295 sft++;
296 div >>= 1;
297 }
298 tmp >>= sft;
299 do_div(tmp, (unsigned long) div);
300 return dclc < 0 ? -tmp : tmp;
301}
302EXPORT_SYMBOL_GPL(__ktime_divns);
303#endif /* BITS_PER_LONG >= 64 */
304
305/*
306 * Add two ktime values and do a safety check for overflow:
307 */
308ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
309{
310 ktime_t res = ktime_add(lhs, rhs);
311
312 /*
313 * We use KTIME_SEC_MAX here, the maximum timeout which we can
314 * return to user space in a timespec:
315 */
316 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
317 res = ktime_set(KTIME_SEC_MAX, 0);
318
319 return res;
320}
321
322EXPORT_SYMBOL_GPL(ktime_add_safe);
323
324#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
325
326static struct debug_obj_descr hrtimer_debug_descr;
327
328static void *hrtimer_debug_hint(void *addr)
329{
330 return ((struct hrtimer *) addr)->function;
331}
332
333/*
334 * fixup_init is called when:
335 * - an active object is initialized
336 */
337static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
338{
339 struct hrtimer *timer = addr;
340
341 switch (state) {
342 case ODEBUG_STATE_ACTIVE:
343 hrtimer_cancel(timer);
344 debug_object_init(timer, &hrtimer_debug_descr);
345 return 1;
346 default:
347 return 0;
348 }
349}
350
351/*
352 * fixup_activate is called when:
353 * - an active object is activated
354 * - an unknown object is activated (might be a statically initialized object)
355 */
356static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
357{
358 switch (state) {
359
360 case ODEBUG_STATE_NOTAVAILABLE:
361 WARN_ON_ONCE(1);
362 return 0;
363
364 case ODEBUG_STATE_ACTIVE:
365 WARN_ON(1);
366
367 default:
368 return 0;
369 }
370}
371
372/*
373 * fixup_free is called when:
374 * - an active object is freed
375 */
376static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
377{
378 struct hrtimer *timer = addr;
379
380 switch (state) {
381 case ODEBUG_STATE_ACTIVE:
382 hrtimer_cancel(timer);
383 debug_object_free(timer, &hrtimer_debug_descr);
384 return 1;
385 default:
386 return 0;
387 }
388}
389
390static struct debug_obj_descr hrtimer_debug_descr = {
391 .name = "hrtimer",
392 .debug_hint = hrtimer_debug_hint,
393 .fixup_init = hrtimer_fixup_init,
394 .fixup_activate = hrtimer_fixup_activate,
395 .fixup_free = hrtimer_fixup_free,
396};
397
398static inline void debug_hrtimer_init(struct hrtimer *timer)
399{
400 debug_object_init(timer, &hrtimer_debug_descr);
401}
402
403static inline void debug_hrtimer_activate(struct hrtimer *timer)
404{
405 debug_object_activate(timer, &hrtimer_debug_descr);
406}
407
408static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
409{
410 debug_object_deactivate(timer, &hrtimer_debug_descr);
411}
412
413static inline void debug_hrtimer_free(struct hrtimer *timer)
414{
415 debug_object_free(timer, &hrtimer_debug_descr);
416}
417
418static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
419 enum hrtimer_mode mode);
420
421void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
422 enum hrtimer_mode mode)
423{
424 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
425 __hrtimer_init(timer, clock_id, mode);
426}
427EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
428
429void destroy_hrtimer_on_stack(struct hrtimer *timer)
430{
431 debug_object_free(timer, &hrtimer_debug_descr);
432}
433
434#else
435static inline void debug_hrtimer_init(struct hrtimer *timer) { }
436static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
437static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
438#endif
439
440static inline void
441debug_init(struct hrtimer *timer, clockid_t clockid,
442 enum hrtimer_mode mode)
443{
444 debug_hrtimer_init(timer);
445 trace_hrtimer_init(timer, clockid, mode);
446}
447
448static inline void debug_activate(struct hrtimer *timer)
449{
450 debug_hrtimer_activate(timer);
451 trace_hrtimer_start(timer);
452}
453
454static inline void debug_deactivate(struct hrtimer *timer)
455{
456 debug_hrtimer_deactivate(timer);
457 trace_hrtimer_cancel(timer);
458}
459
460#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
461static inline void hrtimer_update_next_timer(struct hrtimer_cpu_base *cpu_base,
462 struct hrtimer *timer)
463{
464#ifdef CONFIG_HIGH_RES_TIMERS
465 cpu_base->next_timer = timer;
466#endif
467}
468
469static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
470{
471 struct hrtimer_clock_base *base = cpu_base->clock_base;
472 ktime_t expires, expires_next = { .tv64 = KTIME_MAX };
473 unsigned int active = cpu_base->active_bases;
474
475 hrtimer_update_next_timer(cpu_base, NULL);
476 for (; active; base++, active >>= 1) {
477 struct timerqueue_node *next;
478 struct hrtimer *timer;
479
480 if (!(active & 0x01))
481 continue;
482
483 next = timerqueue_getnext(&base->active);
484 timer = container_of(next, struct hrtimer, node);
485 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
486 if (expires.tv64 < expires_next.tv64) {
487 expires_next = expires;
488 hrtimer_update_next_timer(cpu_base, timer);
489 }
490 }
491 /*
492 * clock_was_set() might have changed base->offset of any of
493 * the clock bases so the result might be negative. Fix it up
494 * to prevent a false positive in clockevents_program_event().
495 */
496 if (expires_next.tv64 < 0)
497 expires_next.tv64 = 0;
498 return expires_next;
499}
500#endif
501
502static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
503{
504 ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
505 ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
506 ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
507
508 return ktime_get_update_offsets_now(&base->clock_was_set_seq,
509 offs_real, offs_boot, offs_tai);
510}
511
512/* High resolution timer related functions */
513#ifdef CONFIG_HIGH_RES_TIMERS
514
515/*
516 * High resolution timer enabled ?
517 */
518static bool hrtimer_hres_enabled __read_mostly = true;
519unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
520EXPORT_SYMBOL_GPL(hrtimer_resolution);
521
522/*
523 * Enable / Disable high resolution mode
524 */
525static int __init setup_hrtimer_hres(char *str)
526{
527 return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
528}
529
530__setup("highres=", setup_hrtimer_hres);
531
532/*
533 * hrtimer_high_res_enabled - query, if the highres mode is enabled
534 */
535static inline int hrtimer_is_hres_enabled(void)
536{
537 return hrtimer_hres_enabled;
538}
539
540/*
541 * Is the high resolution mode active ?
542 */
543static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
544{
545 return cpu_base->hres_active;
546}
547
548static inline int hrtimer_hres_active(void)
549{
550 return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
551}
552
553/*
554 * Reprogram the event source with checking both queues for the
555 * next event
556 * Called with interrupts disabled and base->lock held
557 */
558static void
559hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
560{
561 ktime_t expires_next;
562
563 if (!cpu_base->hres_active)
564 return;
565
566 expires_next = __hrtimer_get_next_event(cpu_base);
567
568 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
569 return;
570
571 cpu_base->expires_next.tv64 = expires_next.tv64;
572
573 /*
574 * If a hang was detected in the last timer interrupt then we
575 * leave the hang delay active in the hardware. We want the
576 * system to make progress. That also prevents the following
577 * scenario:
578 * T1 expires 50ms from now
579 * T2 expires 5s from now
580 *
581 * T1 is removed, so this code is called and would reprogram
582 * the hardware to 5s from now. Any hrtimer_start after that
583 * will not reprogram the hardware due to hang_detected being
584 * set. So we'd effectivly block all timers until the T2 event
585 * fires.
586 */
587 if (cpu_base->hang_detected)
588 return;
589
590 tick_program_event(cpu_base->expires_next, 1);
591}
592
593/*
594 * When a timer is enqueued and expires earlier than the already enqueued
595 * timers, we have to check, whether it expires earlier than the timer for
596 * which the clock event device was armed.
597 *
598 * Called with interrupts disabled and base->cpu_base.lock held
599 */
600static void hrtimer_reprogram(struct hrtimer *timer,
601 struct hrtimer_clock_base *base)
602{
603 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
604 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
605
606 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
607
608 /*
609 * If the timer is not on the current cpu, we cannot reprogram
610 * the other cpus clock event device.
611 */
612 if (base->cpu_base != cpu_base)
613 return;
614
615 /*
616 * If the hrtimer interrupt is running, then it will
617 * reevaluate the clock bases and reprogram the clock event
618 * device. The callbacks are always executed in hard interrupt
619 * context so we don't need an extra check for a running
620 * callback.
621 */
622 if (cpu_base->in_hrtirq)
623 return;
624
625 /*
626 * CLOCK_REALTIME timer might be requested with an absolute
627 * expiry time which is less than base->offset. Set it to 0.
628 */
629 if (expires.tv64 < 0)
630 expires.tv64 = 0;
631
632 if (expires.tv64 >= cpu_base->expires_next.tv64)
633 return;
634
635 /* Update the pointer to the next expiring timer */
636 cpu_base->next_timer = timer;
637
638 /*
639 * If a hang was detected in the last timer interrupt then we
640 * do not schedule a timer which is earlier than the expiry
641 * which we enforced in the hang detection. We want the system
642 * to make progress.
643 */
644 if (cpu_base->hang_detected)
645 return;
646
647 /*
648 * Program the timer hardware. We enforce the expiry for
649 * events which are already in the past.
650 */
651 cpu_base->expires_next = expires;
652 tick_program_event(expires, 1);
653}
654
655/*
656 * Initialize the high resolution related parts of cpu_base
657 */
658static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
659{
660 base->expires_next.tv64 = KTIME_MAX;
661 base->hres_active = 0;
662}
663
664/*
665 * Retrigger next event is called after clock was set
666 *
667 * Called with interrupts disabled via on_each_cpu()
668 */
669static void retrigger_next_event(void *arg)
670{
671 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
672
673 if (!base->hres_active)
674 return;
675
676 raw_spin_lock(&base->lock);
677 hrtimer_update_base(base);
678 hrtimer_force_reprogram(base, 0);
679 raw_spin_unlock(&base->lock);
680}
681
682/*
683 * Switch to high resolution mode
684 */
685static void hrtimer_switch_to_hres(void)
686{
687 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
688
689 if (tick_init_highres()) {
690 printk(KERN_WARNING "Could not switch to high resolution "
691 "mode on CPU %d\n", base->cpu);
692 return;
693 }
694 base->hres_active = 1;
695 hrtimer_resolution = HIGH_RES_NSEC;
696
697 tick_setup_sched_timer();
698 /* "Retrigger" the interrupt to get things going */
699 retrigger_next_event(NULL);
700}
701
702static void clock_was_set_work(struct work_struct *work)
703{
704 clock_was_set();
705}
706
707static DECLARE_WORK(hrtimer_work, clock_was_set_work);
708
709/*
710 * Called from timekeeping and resume code to reprogramm the hrtimer
711 * interrupt device on all cpus.
712 */
713void clock_was_set_delayed(void)
714{
715 schedule_work(&hrtimer_work);
716}
717
718#else
719
720static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *b) { return 0; }
721static inline int hrtimer_hres_active(void) { return 0; }
722static inline int hrtimer_is_hres_enabled(void) { return 0; }
723static inline void hrtimer_switch_to_hres(void) { }
724static inline void
725hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
726static inline int hrtimer_reprogram(struct hrtimer *timer,
727 struct hrtimer_clock_base *base)
728{
729 return 0;
730}
731static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
732static inline void retrigger_next_event(void *arg) { }
733
734#endif /* CONFIG_HIGH_RES_TIMERS */
735
736/*
737 * Clock realtime was set
738 *
739 * Change the offset of the realtime clock vs. the monotonic
740 * clock.
741 *
742 * We might have to reprogram the high resolution timer interrupt. On
743 * SMP we call the architecture specific code to retrigger _all_ high
744 * resolution timer interrupts. On UP we just disable interrupts and
745 * call the high resolution interrupt code.
746 */
747void clock_was_set(void)
748{
749#ifdef CONFIG_HIGH_RES_TIMERS
750 /* Retrigger the CPU local events everywhere */
751 on_each_cpu(retrigger_next_event, NULL, 1);
752#endif
753 timerfd_clock_was_set();
754}
755
756/*
757 * During resume we might have to reprogram the high resolution timer
758 * interrupt on all online CPUs. However, all other CPUs will be
759 * stopped with IRQs interrupts disabled so the clock_was_set() call
760 * must be deferred.
761 */
762void hrtimers_resume(void)
763{
764 WARN_ONCE(!irqs_disabled(),
765 KERN_INFO "hrtimers_resume() called with IRQs enabled!");
766
767 /* Retrigger on the local CPU */
768 retrigger_next_event(NULL);
769 /* And schedule a retrigger for all others */
770 clock_was_set_delayed();
771}
772
773static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
774{
775#ifdef CONFIG_TIMER_STATS
776 if (timer->start_site)
777 return;
778 timer->start_site = __builtin_return_address(0);
779 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
780 timer->start_pid = current->pid;
781#endif
782}
783
784static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
785{
786#ifdef CONFIG_TIMER_STATS
787 timer->start_site = NULL;
788#endif
789}
790
791static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
792{
793#ifdef CONFIG_TIMER_STATS
794 if (likely(!timer_stats_active))
795 return;
796 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
797 timer->function, timer->start_comm, 0);
798#endif
799}
800
801/*
802 * Counterpart to lock_hrtimer_base above:
803 */
804static inline
805void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
806{
807 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
808}
809
810/**
811 * hrtimer_forward - forward the timer expiry
812 * @timer: hrtimer to forward
813 * @now: forward past this time
814 * @interval: the interval to forward
815 *
816 * Forward the timer expiry so it will expire in the future.
817 * Returns the number of overruns.
818 *
819 * Can be safely called from the callback function of @timer. If
820 * called from other contexts @timer must neither be enqueued nor
821 * running the callback and the caller needs to take care of
822 * serialization.
823 *
824 * Note: This only updates the timer expiry value and does not requeue
825 * the timer.
826 */
827u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
828{
829 u64 orun = 1;
830 ktime_t delta;
831
832 delta = ktime_sub(now, hrtimer_get_expires(timer));
833
834 if (delta.tv64 < 0)
835 return 0;
836
837 if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
838 return 0;
839
840 if (interval.tv64 < hrtimer_resolution)
841 interval.tv64 = hrtimer_resolution;
842
843 if (unlikely(delta.tv64 >= interval.tv64)) {
844 s64 incr = ktime_to_ns(interval);
845
846 orun = ktime_divns(delta, incr);
847 hrtimer_add_expires_ns(timer, incr * orun);
848 if (hrtimer_get_expires_tv64(timer) > now.tv64)
849 return orun;
850 /*
851 * This (and the ktime_add() below) is the
852 * correction for exact:
853 */
854 orun++;
855 }
856 hrtimer_add_expires(timer, interval);
857
858 return orun;
859}
860EXPORT_SYMBOL_GPL(hrtimer_forward);
861
862/*
863 * enqueue_hrtimer - internal function to (re)start a timer
864 *
865 * The timer is inserted in expiry order. Insertion into the
866 * red black tree is O(log(n)). Must hold the base lock.
867 *
868 * Returns 1 when the new timer is the leftmost timer in the tree.
869 */
870static int enqueue_hrtimer(struct hrtimer *timer,
871 struct hrtimer_clock_base *base)
872{
873 debug_activate(timer);
874
875 base->cpu_base->active_bases |= 1 << base->index;
876
877 timer->state = HRTIMER_STATE_ENQUEUED;
878
879 return timerqueue_add(&base->active, &timer->node);
880}
881
882/*
883 * __remove_hrtimer - internal function to remove a timer
884 *
885 * Caller must hold the base lock.
886 *
887 * High resolution timer mode reprograms the clock event device when the
888 * timer is the one which expires next. The caller can disable this by setting
889 * reprogram to zero. This is useful, when the context does a reprogramming
890 * anyway (e.g. timer interrupt)
891 */
892static void __remove_hrtimer(struct hrtimer *timer,
893 struct hrtimer_clock_base *base,
894 u8 newstate, int reprogram)
895{
896 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
897 u8 state = timer->state;
898
899 timer->state = newstate;
900 if (!(state & HRTIMER_STATE_ENQUEUED))
901 return;
902
903 if (!timerqueue_del(&base->active, &timer->node))
904 cpu_base->active_bases &= ~(1 << base->index);
905
906#ifdef CONFIG_HIGH_RES_TIMERS
907 /*
908 * Note: If reprogram is false we do not update
909 * cpu_base->next_timer. This happens when we remove the first
910 * timer on a remote cpu. No harm as we never dereference
911 * cpu_base->next_timer. So the worst thing what can happen is
912 * an superflous call to hrtimer_force_reprogram() on the
913 * remote cpu later on if the same timer gets enqueued again.
914 */
915 if (reprogram && timer == cpu_base->next_timer)
916 hrtimer_force_reprogram(cpu_base, 1);
917#endif
918}
919
920/*
921 * remove hrtimer, called with base lock held
922 */
923static inline int
924remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
925{
926 if (hrtimer_is_queued(timer)) {
927 u8 state = timer->state;
928 int reprogram;
929
930 /*
931 * Remove the timer and force reprogramming when high
932 * resolution mode is active and the timer is on the current
933 * CPU. If we remove a timer on another CPU, reprogramming is
934 * skipped. The interrupt event on this CPU is fired and
935 * reprogramming happens in the interrupt handler. This is a
936 * rare case and less expensive than a smp call.
937 */
938 debug_deactivate(timer);
939 timer_stats_hrtimer_clear_start_info(timer);
940 reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
941
942 if (!restart)
943 state = HRTIMER_STATE_INACTIVE;
944
945 __remove_hrtimer(timer, base, state, reprogram);
946 return 1;
947 }
948 return 0;
949}
950
951static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
952 const enum hrtimer_mode mode)
953{
954#ifdef CONFIG_TIME_LOW_RES
955 /*
956 * CONFIG_TIME_LOW_RES indicates that the system has no way to return
957 * granular time values. For relative timers we add hrtimer_resolution
958 * (i.e. one jiffie) to prevent short timeouts.
959 */
960 timer->is_rel = mode & HRTIMER_MODE_REL;
961 if (timer->is_rel)
962 tim = ktime_add_safe(tim, ktime_set(0, hrtimer_resolution));
963#endif
964 return tim;
965}
966
967/**
968 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
969 * @timer: the timer to be added
970 * @tim: expiry time
971 * @delta_ns: "slack" range for the timer
972 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
973 * relative (HRTIMER_MODE_REL)
974 */
975void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
976 u64 delta_ns, const enum hrtimer_mode mode)
977{
978 struct hrtimer_clock_base *base, *new_base;
979 unsigned long flags;
980 int leftmost;
981
982 base = lock_hrtimer_base(timer, &flags);
983
984 /* Remove an active timer from the queue: */
985 remove_hrtimer(timer, base, true);
986
987 if (mode & HRTIMER_MODE_REL)
988 tim = ktime_add_safe(tim, base->get_time());
989
990 tim = hrtimer_update_lowres(timer, tim, mode);
991
992 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
993
994 /* Switch the timer base, if necessary: */
995 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
996
997 timer_stats_hrtimer_set_start_info(timer);
998
999 leftmost = enqueue_hrtimer(timer, new_base);
1000 if (!leftmost)
1001 goto unlock;
1002
1003 if (!hrtimer_is_hres_active(timer)) {
1004 /*
1005 * Kick to reschedule the next tick to handle the new timer
1006 * on dynticks target.
1007 */
1008 if (new_base->cpu_base->nohz_active)
1009 wake_up_nohz_cpu(new_base->cpu_base->cpu);
1010 } else {
1011 hrtimer_reprogram(timer, new_base);
1012 }
1013unlock:
1014 unlock_hrtimer_base(timer, &flags);
1015}
1016EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1017
1018/**
1019 * hrtimer_try_to_cancel - try to deactivate a timer
1020 * @timer: hrtimer to stop
1021 *
1022 * Returns:
1023 * 0 when the timer was not active
1024 * 1 when the timer was active
1025 * -1 when the timer is currently excuting the callback function and
1026 * cannot be stopped
1027 */
1028int hrtimer_try_to_cancel(struct hrtimer *timer)
1029{
1030 struct hrtimer_clock_base *base;
1031 unsigned long flags;
1032 int ret = -1;
1033
1034 /*
1035 * Check lockless first. If the timer is not active (neither
1036 * enqueued nor running the callback, nothing to do here. The
1037 * base lock does not serialize against a concurrent enqueue,
1038 * so we can avoid taking it.
1039 */
1040 if (!hrtimer_active(timer))
1041 return 0;
1042
1043 base = lock_hrtimer_base(timer, &flags);
1044
1045 if (!hrtimer_callback_running(timer))
1046 ret = remove_hrtimer(timer, base, false);
1047
1048 unlock_hrtimer_base(timer, &flags);
1049
1050 return ret;
1051
1052}
1053EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1054
1055/**
1056 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1057 * @timer: the timer to be cancelled
1058 *
1059 * Returns:
1060 * 0 when the timer was not active
1061 * 1 when the timer was active
1062 */
1063int hrtimer_cancel(struct hrtimer *timer)
1064{
1065 for (;;) {
1066 int ret = hrtimer_try_to_cancel(timer);
1067
1068 if (ret >= 0)
1069 return ret;
1070 cpu_relax();
1071 }
1072}
1073EXPORT_SYMBOL_GPL(hrtimer_cancel);
1074
1075/**
1076 * hrtimer_get_remaining - get remaining time for the timer
1077 * @timer: the timer to read
1078 * @adjust: adjust relative timers when CONFIG_TIME_LOW_RES=y
1079 */
1080ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
1081{
1082 unsigned long flags;
1083 ktime_t rem;
1084
1085 lock_hrtimer_base(timer, &flags);
1086 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
1087 rem = hrtimer_expires_remaining_adjusted(timer);
1088 else
1089 rem = hrtimer_expires_remaining(timer);
1090 unlock_hrtimer_base(timer, &flags);
1091
1092 return rem;
1093}
1094EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
1095
1096#ifdef CONFIG_NO_HZ_COMMON
1097/**
1098 * hrtimer_get_next_event - get the time until next expiry event
1099 *
1100 * Returns the next expiry time or KTIME_MAX if no timer is pending.
1101 */
1102u64 hrtimer_get_next_event(void)
1103{
1104 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1105 u64 expires = KTIME_MAX;
1106 unsigned long flags;
1107
1108 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1109
1110 if (!__hrtimer_hres_active(cpu_base))
1111 expires = __hrtimer_get_next_event(cpu_base).tv64;
1112
1113 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1114
1115 return expires;
1116}
1117#endif
1118
1119static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1120 enum hrtimer_mode mode)
1121{
1122 struct hrtimer_cpu_base *cpu_base;
1123 int base;
1124
1125 memset(timer, 0, sizeof(struct hrtimer));
1126
1127 cpu_base = raw_cpu_ptr(&hrtimer_bases);
1128
1129 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1130 clock_id = CLOCK_MONOTONIC;
1131
1132 base = hrtimer_clockid_to_base(clock_id);
1133 timer->base = &cpu_base->clock_base[base];
1134 timerqueue_init(&timer->node);
1135
1136#ifdef CONFIG_TIMER_STATS
1137 timer->start_site = NULL;
1138 timer->start_pid = -1;
1139 memset(timer->start_comm, 0, TASK_COMM_LEN);
1140#endif
1141}
1142
1143/**
1144 * hrtimer_init - initialize a timer to the given clock
1145 * @timer: the timer to be initialized
1146 * @clock_id: the clock to be used
1147 * @mode: timer mode abs/rel
1148 */
1149void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1150 enum hrtimer_mode mode)
1151{
1152 debug_init(timer, clock_id, mode);
1153 __hrtimer_init(timer, clock_id, mode);
1154}
1155EXPORT_SYMBOL_GPL(hrtimer_init);
1156
1157/*
1158 * A timer is active, when it is enqueued into the rbtree or the
1159 * callback function is running or it's in the state of being migrated
1160 * to another cpu.
1161 *
1162 * It is important for this function to not return a false negative.
1163 */
1164bool hrtimer_active(const struct hrtimer *timer)
1165{
1166 struct hrtimer_cpu_base *cpu_base;
1167 unsigned int seq;
1168
1169 do {
1170 cpu_base = READ_ONCE(timer->base->cpu_base);
1171 seq = raw_read_seqcount_begin(&cpu_base->seq);
1172
1173 if (timer->state != HRTIMER_STATE_INACTIVE ||
1174 cpu_base->running == timer)
1175 return true;
1176
1177 } while (read_seqcount_retry(&cpu_base->seq, seq) ||
1178 cpu_base != READ_ONCE(timer->base->cpu_base));
1179
1180 return false;
1181}
1182EXPORT_SYMBOL_GPL(hrtimer_active);
1183
1184/*
1185 * The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
1186 * distinct sections:
1187 *
1188 * - queued: the timer is queued
1189 * - callback: the timer is being ran
1190 * - post: the timer is inactive or (re)queued
1191 *
1192 * On the read side we ensure we observe timer->state and cpu_base->running
1193 * from the same section, if anything changed while we looked at it, we retry.
1194 * This includes timer->base changing because sequence numbers alone are
1195 * insufficient for that.
1196 *
1197 * The sequence numbers are required because otherwise we could still observe
1198 * a false negative if the read side got smeared over multiple consequtive
1199 * __run_hrtimer() invocations.
1200 */
1201
1202static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
1203 struct hrtimer_clock_base *base,
1204 struct hrtimer *timer, ktime_t *now)
1205{
1206 enum hrtimer_restart (*fn)(struct hrtimer *);
1207 int restart;
1208
1209 lockdep_assert_held(&cpu_base->lock);
1210
1211 debug_deactivate(timer);
1212 cpu_base->running = timer;
1213
1214 /*
1215 * Separate the ->running assignment from the ->state assignment.
1216 *
1217 * As with a regular write barrier, this ensures the read side in
1218 * hrtimer_active() cannot observe cpu_base->running == NULL &&
1219 * timer->state == INACTIVE.
1220 */
1221 raw_write_seqcount_barrier(&cpu_base->seq);
1222
1223 __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
1224 timer_stats_account_hrtimer(timer);
1225 fn = timer->function;
1226
1227 /*
1228 * Clear the 'is relative' flag for the TIME_LOW_RES case. If the
1229 * timer is restarted with a period then it becomes an absolute
1230 * timer. If its not restarted it does not matter.
1231 */
1232 if (IS_ENABLED(CONFIG_TIME_LOW_RES))
1233 timer->is_rel = false;
1234
1235 /*
1236 * Because we run timers from hardirq context, there is no chance
1237 * they get migrated to another cpu, therefore its safe to unlock
1238 * the timer base.
1239 */
1240 raw_spin_unlock(&cpu_base->lock);
1241 trace_hrtimer_expire_entry(timer, now);
1242 restart = fn(timer);
1243 trace_hrtimer_expire_exit(timer);
1244 raw_spin_lock(&cpu_base->lock);
1245
1246 /*
1247 * Note: We clear the running state after enqueue_hrtimer and
1248 * we do not reprogramm the event hardware. Happens either in
1249 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1250 *
1251 * Note: Because we dropped the cpu_base->lock above,
1252 * hrtimer_start_range_ns() can have popped in and enqueued the timer
1253 * for us already.
1254 */
1255 if (restart != HRTIMER_NORESTART &&
1256 !(timer->state & HRTIMER_STATE_ENQUEUED))
1257 enqueue_hrtimer(timer, base);
1258
1259 /*
1260 * Separate the ->running assignment from the ->state assignment.
1261 *
1262 * As with a regular write barrier, this ensures the read side in
1263 * hrtimer_active() cannot observe cpu_base->running == NULL &&
1264 * timer->state == INACTIVE.
1265 */
1266 raw_write_seqcount_barrier(&cpu_base->seq);
1267
1268 WARN_ON_ONCE(cpu_base->running != timer);
1269 cpu_base->running = NULL;
1270}
1271
1272static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
1273{
1274 struct hrtimer_clock_base *base = cpu_base->clock_base;
1275 unsigned int active = cpu_base->active_bases;
1276
1277 for (; active; base++, active >>= 1) {
1278 struct timerqueue_node *node;
1279 ktime_t basenow;
1280
1281 if (!(active & 0x01))
1282 continue;
1283
1284 basenow = ktime_add(now, base->offset);
1285
1286 while ((node = timerqueue_getnext(&base->active))) {
1287 struct hrtimer *timer;
1288
1289 timer = container_of(node, struct hrtimer, node);
1290
1291 /*
1292 * The immediate goal for using the softexpires is
1293 * minimizing wakeups, not running timers at the
1294 * earliest interrupt after their soft expiration.
1295 * This allows us to avoid using a Priority Search
1296 * Tree, which can answer a stabbing querry for
1297 * overlapping intervals and instead use the simple
1298 * BST we already have.
1299 * We don't add extra wakeups by delaying timers that
1300 * are right-of a not yet expired timer, because that
1301 * timer will have to trigger a wakeup anyway.
1302 */
1303 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer))
1304 break;
1305
1306 __run_hrtimer(cpu_base, base, timer, &basenow);
1307 }
1308 }
1309}
1310
1311#ifdef CONFIG_HIGH_RES_TIMERS
1312
1313/*
1314 * High resolution timer interrupt
1315 * Called with interrupts disabled
1316 */
1317void hrtimer_interrupt(struct clock_event_device *dev)
1318{
1319 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1320 ktime_t expires_next, now, entry_time, delta;
1321 int retries = 0;
1322
1323 BUG_ON(!cpu_base->hres_active);
1324 cpu_base->nr_events++;
1325 dev->next_event.tv64 = KTIME_MAX;
1326
1327 raw_spin_lock(&cpu_base->lock);
1328 entry_time = now = hrtimer_update_base(cpu_base);
1329retry:
1330 cpu_base->in_hrtirq = 1;
1331 /*
1332 * We set expires_next to KTIME_MAX here with cpu_base->lock
1333 * held to prevent that a timer is enqueued in our queue via
1334 * the migration code. This does not affect enqueueing of
1335 * timers which run their callback and need to be requeued on
1336 * this CPU.
1337 */
1338 cpu_base->expires_next.tv64 = KTIME_MAX;
1339
1340 __hrtimer_run_queues(cpu_base, now);
1341
1342 /* Reevaluate the clock bases for the next expiry */
1343 expires_next = __hrtimer_get_next_event(cpu_base);
1344 /*
1345 * Store the new expiry value so the migration code can verify
1346 * against it.
1347 */
1348 cpu_base->expires_next = expires_next;
1349 cpu_base->in_hrtirq = 0;
1350 raw_spin_unlock(&cpu_base->lock);
1351
1352 /* Reprogramming necessary ? */
1353 if (!tick_program_event(expires_next, 0)) {
1354 cpu_base->hang_detected = 0;
1355 return;
1356 }
1357
1358 /*
1359 * The next timer was already expired due to:
1360 * - tracing
1361 * - long lasting callbacks
1362 * - being scheduled away when running in a VM
1363 *
1364 * We need to prevent that we loop forever in the hrtimer
1365 * interrupt routine. We give it 3 attempts to avoid
1366 * overreacting on some spurious event.
1367 *
1368 * Acquire base lock for updating the offsets and retrieving
1369 * the current time.
1370 */
1371 raw_spin_lock(&cpu_base->lock);
1372 now = hrtimer_update_base(cpu_base);
1373 cpu_base->nr_retries++;
1374 if (++retries < 3)
1375 goto retry;
1376 /*
1377 * Give the system a chance to do something else than looping
1378 * here. We stored the entry time, so we know exactly how long
1379 * we spent here. We schedule the next event this amount of
1380 * time away.
1381 */
1382 cpu_base->nr_hangs++;
1383 cpu_base->hang_detected = 1;
1384 raw_spin_unlock(&cpu_base->lock);
1385 delta = ktime_sub(now, entry_time);
1386 if ((unsigned int)delta.tv64 > cpu_base->max_hang_time)
1387 cpu_base->max_hang_time = (unsigned int) delta.tv64;
1388 /*
1389 * Limit it to a sensible value as we enforce a longer
1390 * delay. Give the CPU at least 100ms to catch up.
1391 */
1392 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1393 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1394 else
1395 expires_next = ktime_add(now, delta);
1396 tick_program_event(expires_next, 1);
1397 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1398 ktime_to_ns(delta));
1399}
1400
1401/*
1402 * local version of hrtimer_peek_ahead_timers() called with interrupts
1403 * disabled.
1404 */
1405static inline void __hrtimer_peek_ahead_timers(void)
1406{
1407 struct tick_device *td;
1408
1409 if (!hrtimer_hres_active())
1410 return;
1411
1412 td = this_cpu_ptr(&tick_cpu_device);
1413 if (td && td->evtdev)
1414 hrtimer_interrupt(td->evtdev);
1415}
1416
1417#else /* CONFIG_HIGH_RES_TIMERS */
1418
1419static inline void __hrtimer_peek_ahead_timers(void) { }
1420
1421#endif /* !CONFIG_HIGH_RES_TIMERS */
1422
1423/*
1424 * Called from run_local_timers in hardirq context every jiffy
1425 */
1426void hrtimer_run_queues(void)
1427{
1428 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1429 ktime_t now;
1430
1431 if (__hrtimer_hres_active(cpu_base))
1432 return;
1433
1434 /*
1435 * This _is_ ugly: We have to check periodically, whether we
1436 * can switch to highres and / or nohz mode. The clocksource
1437 * switch happens with xtime_lock held. Notification from
1438 * there only sets the check bit in the tick_oneshot code,
1439 * otherwise we might deadlock vs. xtime_lock.
1440 */
1441 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
1442 hrtimer_switch_to_hres();
1443 return;
1444 }
1445
1446 raw_spin_lock(&cpu_base->lock);
1447 now = hrtimer_update_base(cpu_base);
1448 __hrtimer_run_queues(cpu_base, now);
1449 raw_spin_unlock(&cpu_base->lock);
1450}
1451
1452/*
1453 * Sleep related functions:
1454 */
1455static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1456{
1457 struct hrtimer_sleeper *t =
1458 container_of(timer, struct hrtimer_sleeper, timer);
1459 struct task_struct *task = t->task;
1460
1461 t->task = NULL;
1462 if (task)
1463 wake_up_process(task);
1464
1465 return HRTIMER_NORESTART;
1466}
1467
1468void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1469{
1470 sl->timer.function = hrtimer_wakeup;
1471 sl->task = task;
1472}
1473EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1474
1475static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1476{
1477 hrtimer_init_sleeper(t, current);
1478
1479 do {
1480 set_current_state(TASK_INTERRUPTIBLE);
1481 hrtimer_start_expires(&t->timer, mode);
1482
1483 if (likely(t->task))
1484 freezable_schedule();
1485
1486 hrtimer_cancel(&t->timer);
1487 mode = HRTIMER_MODE_ABS;
1488
1489 } while (t->task && !signal_pending(current));
1490
1491 __set_current_state(TASK_RUNNING);
1492
1493 return t->task == NULL;
1494}
1495
1496static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1497{
1498 struct timespec rmt;
1499 ktime_t rem;
1500
1501 rem = hrtimer_expires_remaining(timer);
1502 if (rem.tv64 <= 0)
1503 return 0;
1504 rmt = ktime_to_timespec(rem);
1505
1506 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1507 return -EFAULT;
1508
1509 return 1;
1510}
1511
1512long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1513{
1514 struct hrtimer_sleeper t;
1515 struct timespec __user *rmtp;
1516 int ret = 0;
1517
1518 hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
1519 HRTIMER_MODE_ABS);
1520 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1521
1522 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1523 goto out;
1524
1525 rmtp = restart->nanosleep.rmtp;
1526 if (rmtp) {
1527 ret = update_rmtp(&t.timer, rmtp);
1528 if (ret <= 0)
1529 goto out;
1530 }
1531
1532 /* The other values in restart are already filled in */
1533 ret = -ERESTART_RESTARTBLOCK;
1534out:
1535 destroy_hrtimer_on_stack(&t.timer);
1536 return ret;
1537}
1538
1539long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1540 const enum hrtimer_mode mode, const clockid_t clockid)
1541{
1542 struct restart_block *restart;
1543 struct hrtimer_sleeper t;
1544 int ret = 0;
1545 u64 slack;
1546
1547 slack = current->timer_slack_ns;
1548 if (dl_task(current) || rt_task(current))
1549 slack = 0;
1550
1551 hrtimer_init_on_stack(&t.timer, clockid, mode);
1552 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1553 if (do_nanosleep(&t, mode))
1554 goto out;
1555
1556 /* Absolute timers do not update the rmtp value and restart: */
1557 if (mode == HRTIMER_MODE_ABS) {
1558 ret = -ERESTARTNOHAND;
1559 goto out;
1560 }
1561
1562 if (rmtp) {
1563 ret = update_rmtp(&t.timer, rmtp);
1564 if (ret <= 0)
1565 goto out;
1566 }
1567
1568 restart = ¤t->restart_block;
1569 restart->fn = hrtimer_nanosleep_restart;
1570 restart->nanosleep.clockid = t.timer.base->clockid;
1571 restart->nanosleep.rmtp = rmtp;
1572 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1573
1574 ret = -ERESTART_RESTARTBLOCK;
1575out:
1576 destroy_hrtimer_on_stack(&t.timer);
1577 return ret;
1578}
1579
1580SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1581 struct timespec __user *, rmtp)
1582{
1583 struct timespec tu;
1584
1585 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1586 return -EFAULT;
1587
1588 if (!timespec_valid(&tu))
1589 return -EINVAL;
1590
1591 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1592}
1593
1594/*
1595 * Functions related to boot-time initialization:
1596 */
1597static void init_hrtimers_cpu(int cpu)
1598{
1599 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1600 int i;
1601
1602 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1603 cpu_base->clock_base[i].cpu_base = cpu_base;
1604 timerqueue_init_head(&cpu_base->clock_base[i].active);
1605 }
1606
1607 cpu_base->cpu = cpu;
1608 hrtimer_init_hres(cpu_base);
1609}
1610
1611#ifdef CONFIG_HOTPLUG_CPU
1612
1613static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1614 struct hrtimer_clock_base *new_base)
1615{
1616 struct hrtimer *timer;
1617 struct timerqueue_node *node;
1618
1619 while ((node = timerqueue_getnext(&old_base->active))) {
1620 timer = container_of(node, struct hrtimer, node);
1621 BUG_ON(hrtimer_callback_running(timer));
1622 debug_deactivate(timer);
1623
1624 /*
1625 * Mark it as ENQUEUED not INACTIVE otherwise the
1626 * timer could be seen as !active and just vanish away
1627 * under us on another CPU
1628 */
1629 __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
1630 timer->base = new_base;
1631 /*
1632 * Enqueue the timers on the new cpu. This does not
1633 * reprogram the event device in case the timer
1634 * expires before the earliest on this CPU, but we run
1635 * hrtimer_interrupt after we migrated everything to
1636 * sort out already expired timers and reprogram the
1637 * event device.
1638 */
1639 enqueue_hrtimer(timer, new_base);
1640 }
1641}
1642
1643static void migrate_hrtimers(int scpu)
1644{
1645 struct hrtimer_cpu_base *old_base, *new_base;
1646 int i;
1647
1648 BUG_ON(cpu_online(scpu));
1649 tick_cancel_sched_timer(scpu);
1650
1651 local_irq_disable();
1652 old_base = &per_cpu(hrtimer_bases, scpu);
1653 new_base = this_cpu_ptr(&hrtimer_bases);
1654 /*
1655 * The caller is globally serialized and nobody else
1656 * takes two locks at once, deadlock is not possible.
1657 */
1658 raw_spin_lock(&new_base->lock);
1659 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1660
1661 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1662 migrate_hrtimer_list(&old_base->clock_base[i],
1663 &new_base->clock_base[i]);
1664 }
1665
1666 raw_spin_unlock(&old_base->lock);
1667 raw_spin_unlock(&new_base->lock);
1668
1669 /* Check, if we got expired work to do */
1670 __hrtimer_peek_ahead_timers();
1671 local_irq_enable();
1672}
1673
1674#endif /* CONFIG_HOTPLUG_CPU */
1675
1676static int hrtimer_cpu_notify(struct notifier_block *self,
1677 unsigned long action, void *hcpu)
1678{
1679 int scpu = (long)hcpu;
1680
1681 switch (action) {
1682
1683 case CPU_UP_PREPARE:
1684 case CPU_UP_PREPARE_FROZEN:
1685 init_hrtimers_cpu(scpu);
1686 break;
1687
1688#ifdef CONFIG_HOTPLUG_CPU
1689 case CPU_DEAD:
1690 case CPU_DEAD_FROZEN:
1691 migrate_hrtimers(scpu);
1692 break;
1693#endif
1694
1695 default:
1696 break;
1697 }
1698
1699 return NOTIFY_OK;
1700}
1701
1702static struct notifier_block hrtimers_nb = {
1703 .notifier_call = hrtimer_cpu_notify,
1704};
1705
1706void __init hrtimers_init(void)
1707{
1708 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1709 (void *)(long)smp_processor_id());
1710 register_cpu_notifier(&hrtimers_nb);
1711}
1712
1713/**
1714 * schedule_hrtimeout_range_clock - sleep until timeout
1715 * @expires: timeout value (ktime_t)
1716 * @delta: slack in expires timeout (ktime_t)
1717 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1718 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1719 */
1720int __sched
1721schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
1722 const enum hrtimer_mode mode, int clock)
1723{
1724 struct hrtimer_sleeper t;
1725
1726 /*
1727 * Optimize when a zero timeout value is given. It does not
1728 * matter whether this is an absolute or a relative time.
1729 */
1730 if (expires && !expires->tv64) {
1731 __set_current_state(TASK_RUNNING);
1732 return 0;
1733 }
1734
1735 /*
1736 * A NULL parameter means "infinite"
1737 */
1738 if (!expires) {
1739 schedule();
1740 return -EINTR;
1741 }
1742
1743 hrtimer_init_on_stack(&t.timer, clock, mode);
1744 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1745
1746 hrtimer_init_sleeper(&t, current);
1747
1748 hrtimer_start_expires(&t.timer, mode);
1749
1750 if (likely(t.task))
1751 schedule();
1752
1753 hrtimer_cancel(&t.timer);
1754 destroy_hrtimer_on_stack(&t.timer);
1755
1756 __set_current_state(TASK_RUNNING);
1757
1758 return !t.task ? 0 : -EINTR;
1759}
1760
1761/**
1762 * schedule_hrtimeout_range - sleep until timeout
1763 * @expires: timeout value (ktime_t)
1764 * @delta: slack in expires timeout (ktime_t)
1765 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1766 *
1767 * Make the current task sleep until the given expiry time has
1768 * elapsed. The routine will return immediately unless
1769 * the current task state has been set (see set_current_state()).
1770 *
1771 * The @delta argument gives the kernel the freedom to schedule the
1772 * actual wakeup to a time that is both power and performance friendly.
1773 * The kernel give the normal best effort behavior for "@expires+@delta",
1774 * but may decide to fire the timer earlier, but no earlier than @expires.
1775 *
1776 * You can set the task state as follows -
1777 *
1778 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1779 * pass before the routine returns.
1780 *
1781 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1782 * delivered to the current task.
1783 *
1784 * The current task state is guaranteed to be TASK_RUNNING when this
1785 * routine returns.
1786 *
1787 * Returns 0 when the timer has expired otherwise -EINTR
1788 */
1789int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
1790 const enum hrtimer_mode mode)
1791{
1792 return schedule_hrtimeout_range_clock(expires, delta, mode,
1793 CLOCK_MONOTONIC);
1794}
1795EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1796
1797/**
1798 * schedule_hrtimeout - sleep until timeout
1799 * @expires: timeout value (ktime_t)
1800 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1801 *
1802 * Make the current task sleep until the given expiry time has
1803 * elapsed. The routine will return immediately unless
1804 * the current task state has been set (see set_current_state()).
1805 *
1806 * You can set the task state as follows -
1807 *
1808 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1809 * pass before the routine returns.
1810 *
1811 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1812 * delivered to the current task.
1813 *
1814 * The current task state is guaranteed to be TASK_RUNNING when this
1815 * routine returns.
1816 *
1817 * Returns 0 when the timer has expired otherwise -EINTR
1818 */
1819int __sched schedule_hrtimeout(ktime_t *expires,
1820 const enum hrtimer_mode mode)
1821{
1822 return schedule_hrtimeout_range(expires, 0, mode);
1823}
1824EXPORT_SYMBOL_GPL(schedule_hrtimeout);
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 */
68DEFINE_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
116static 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 */
137static struct hrtimer_cpu_base migration_cpu_base = {
138 .clock_base = { {
139 .cpu_base = &migration_cpu_base,
140 .seq = SEQCNT_RAW_SPINLOCK_ZERO(migration_cpu_base.seq,
141 &migration_cpu_base.lock),
142 }, },
143};
144
145#define migration_base migration_cpu_base.clock_base[0]
146
147static inline bool is_migration_base(struct hrtimer_clock_base *base)
148{
149 return base == &migration_base;
150}
151
152/*
153 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
154 * means that all timers which are tied to this base via timer->base are
155 * locked, and the base itself is locked too.
156 *
157 * So __run_timers/migrate_timers can safely modify all timers which could
158 * be found on the lists/queues.
159 *
160 * When the timer's base is locked, and the timer removed from list, it is
161 * possible to set timer->base = &migration_base and drop the lock: the timer
162 * remains locked.
163 */
164static
165struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
166 unsigned long *flags)
167 __acquires(&timer->base->lock)
168{
169 struct hrtimer_clock_base *base;
170
171 for (;;) {
172 base = READ_ONCE(timer->base);
173 if (likely(base != &migration_base)) {
174 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
175 if (likely(base == timer->base))
176 return base;
177 /* The timer has migrated to another CPU: */
178 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
179 }
180 cpu_relax();
181 }
182}
183
184/*
185 * We do not migrate the timer when it is expiring before the next
186 * event on the target cpu. When high resolution is enabled, we cannot
187 * reprogram the target cpu hardware and we would cause it to fire
188 * late. To keep it simple, we handle the high resolution enabled and
189 * disabled case similar.
190 *
191 * Called with cpu_base->lock of target cpu held.
192 */
193static int
194hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
195{
196 ktime_t expires;
197
198 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
199 return expires < new_base->cpu_base->expires_next;
200}
201
202static inline
203struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
204 int pinned)
205{
206#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
207 if (static_branch_likely(&timers_migration_enabled) && !pinned)
208 return &per_cpu(hrtimer_bases, get_nohz_timer_target());
209#endif
210 return base;
211}
212
213/*
214 * We switch the timer base to a power-optimized selected CPU target,
215 * if:
216 * - NO_HZ_COMMON is enabled
217 * - timer migration is enabled
218 * - the timer callback is not running
219 * - the timer is not the first expiring timer on the new target
220 *
221 * If one of the above requirements is not fulfilled we move the timer
222 * to the current CPU or leave it on the previously assigned CPU if
223 * the timer callback is currently running.
224 */
225static inline struct hrtimer_clock_base *
226switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
227 int pinned)
228{
229 struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
230 struct hrtimer_clock_base *new_base;
231 int basenum = base->index;
232
233 this_cpu_base = this_cpu_ptr(&hrtimer_bases);
234 new_cpu_base = get_target_base(this_cpu_base, pinned);
235again:
236 new_base = &new_cpu_base->clock_base[basenum];
237
238 if (base != new_base) {
239 /*
240 * We are trying to move timer to new_base.
241 * However we can't change timer's base while it is running,
242 * so we keep it on the same CPU. No hassle vs. reprogramming
243 * the event source in the high resolution case. The softirq
244 * code will take care of this when the timer function has
245 * completed. There is no conflict as we hold the lock until
246 * the timer is enqueued.
247 */
248 if (unlikely(hrtimer_callback_running(timer)))
249 return base;
250
251 /* See the comment in lock_hrtimer_base() */
252 WRITE_ONCE(timer->base, &migration_base);
253 raw_spin_unlock(&base->cpu_base->lock);
254 raw_spin_lock(&new_base->cpu_base->lock);
255
256 if (new_cpu_base != this_cpu_base &&
257 hrtimer_check_target(timer, new_base)) {
258 raw_spin_unlock(&new_base->cpu_base->lock);
259 raw_spin_lock(&base->cpu_base->lock);
260 new_cpu_base = this_cpu_base;
261 WRITE_ONCE(timer->base, base);
262 goto again;
263 }
264 WRITE_ONCE(timer->base, new_base);
265 } else {
266 if (new_cpu_base != this_cpu_base &&
267 hrtimer_check_target(timer, new_base)) {
268 new_cpu_base = this_cpu_base;
269 goto again;
270 }
271 }
272 return new_base;
273}
274
275#else /* CONFIG_SMP */
276
277static inline bool is_migration_base(struct hrtimer_clock_base *base)
278{
279 return false;
280}
281
282static inline struct hrtimer_clock_base *
283lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
284 __acquires(&timer->base->cpu_base->lock)
285{
286 struct hrtimer_clock_base *base = timer->base;
287
288 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
289
290 return base;
291}
292
293# define switch_hrtimer_base(t, b, p) (b)
294
295#endif /* !CONFIG_SMP */
296
297/*
298 * Functions for the union type storage format of ktime_t which are
299 * too large for inlining:
300 */
301#if BITS_PER_LONG < 64
302/*
303 * Divide a ktime value by a nanosecond value
304 */
305s64 __ktime_divns(const ktime_t kt, s64 div)
306{
307 int sft = 0;
308 s64 dclc;
309 u64 tmp;
310
311 dclc = ktime_to_ns(kt);
312 tmp = dclc < 0 ? -dclc : dclc;
313
314 /* Make sure the divisor is less than 2^32: */
315 while (div >> 32) {
316 sft++;
317 div >>= 1;
318 }
319 tmp >>= sft;
320 do_div(tmp, (u32) div);
321 return dclc < 0 ? -tmp : tmp;
322}
323EXPORT_SYMBOL_GPL(__ktime_divns);
324#endif /* BITS_PER_LONG >= 64 */
325
326/*
327 * Add two ktime values and do a safety check for overflow:
328 */
329ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
330{
331 ktime_t res = ktime_add_unsafe(lhs, rhs);
332
333 /*
334 * We use KTIME_SEC_MAX here, the maximum timeout which we can
335 * return to user space in a timespec:
336 */
337 if (res < 0 || res < lhs || res < rhs)
338 res = ktime_set(KTIME_SEC_MAX, 0);
339
340 return res;
341}
342
343EXPORT_SYMBOL_GPL(ktime_add_safe);
344
345#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
346
347static const struct debug_obj_descr hrtimer_debug_descr;
348
349static void *hrtimer_debug_hint(void *addr)
350{
351 return ((struct hrtimer *) addr)->function;
352}
353
354/*
355 * fixup_init is called when:
356 * - an active object is initialized
357 */
358static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
359{
360 struct hrtimer *timer = addr;
361
362 switch (state) {
363 case ODEBUG_STATE_ACTIVE:
364 hrtimer_cancel(timer);
365 debug_object_init(timer, &hrtimer_debug_descr);
366 return true;
367 default:
368 return false;
369 }
370}
371
372/*
373 * fixup_activate is called when:
374 * - an active object is activated
375 * - an unknown non-static object is activated
376 */
377static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
378{
379 switch (state) {
380 case ODEBUG_STATE_ACTIVE:
381 WARN_ON(1);
382 fallthrough;
383 default:
384 return false;
385 }
386}
387
388/*
389 * fixup_free is called when:
390 * - an active object is freed
391 */
392static bool hrtimer_fixup_free(void *addr, enum debug_obj_state state)
393{
394 struct hrtimer *timer = addr;
395
396 switch (state) {
397 case ODEBUG_STATE_ACTIVE:
398 hrtimer_cancel(timer);
399 debug_object_free(timer, &hrtimer_debug_descr);
400 return true;
401 default:
402 return false;
403 }
404}
405
406static const struct debug_obj_descr hrtimer_debug_descr = {
407 .name = "hrtimer",
408 .debug_hint = hrtimer_debug_hint,
409 .fixup_init = hrtimer_fixup_init,
410 .fixup_activate = hrtimer_fixup_activate,
411 .fixup_free = hrtimer_fixup_free,
412};
413
414static inline void debug_hrtimer_init(struct hrtimer *timer)
415{
416 debug_object_init(timer, &hrtimer_debug_descr);
417}
418
419static inline void debug_hrtimer_activate(struct hrtimer *timer,
420 enum hrtimer_mode mode)
421{
422 debug_object_activate(timer, &hrtimer_debug_descr);
423}
424
425static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
426{
427 debug_object_deactivate(timer, &hrtimer_debug_descr);
428}
429
430static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
431 enum hrtimer_mode mode);
432
433void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
434 enum hrtimer_mode mode)
435{
436 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
437 __hrtimer_init(timer, clock_id, mode);
438}
439EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
440
441static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
442 clockid_t clock_id, enum hrtimer_mode mode);
443
444void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
445 clockid_t clock_id, enum hrtimer_mode mode)
446{
447 debug_object_init_on_stack(&sl->timer, &hrtimer_debug_descr);
448 __hrtimer_init_sleeper(sl, clock_id, mode);
449}
450EXPORT_SYMBOL_GPL(hrtimer_init_sleeper_on_stack);
451
452void destroy_hrtimer_on_stack(struct hrtimer *timer)
453{
454 debug_object_free(timer, &hrtimer_debug_descr);
455}
456EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
457
458#else
459
460static inline void debug_hrtimer_init(struct hrtimer *timer) { }
461static inline void debug_hrtimer_activate(struct hrtimer *timer,
462 enum hrtimer_mode mode) { }
463static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
464#endif
465
466static inline void
467debug_init(struct hrtimer *timer, clockid_t clockid,
468 enum hrtimer_mode mode)
469{
470 debug_hrtimer_init(timer);
471 trace_hrtimer_init(timer, clockid, mode);
472}
473
474static inline void debug_activate(struct hrtimer *timer,
475 enum hrtimer_mode mode)
476{
477 debug_hrtimer_activate(timer, mode);
478 trace_hrtimer_start(timer, mode);
479}
480
481static inline void debug_deactivate(struct hrtimer *timer)
482{
483 debug_hrtimer_deactivate(timer);
484 trace_hrtimer_cancel(timer);
485}
486
487static struct hrtimer_clock_base *
488__next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active)
489{
490 unsigned int idx;
491
492 if (!*active)
493 return NULL;
494
495 idx = __ffs(*active);
496 *active &= ~(1U << idx);
497
498 return &cpu_base->clock_base[idx];
499}
500
501#define for_each_active_base(base, cpu_base, active) \
502 while ((base = __next_base((cpu_base), &(active))))
503
504static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
505 const struct hrtimer *exclude,
506 unsigned int active,
507 ktime_t expires_next)
508{
509 struct hrtimer_clock_base *base;
510 ktime_t expires;
511
512 for_each_active_base(base, cpu_base, active) {
513 struct timerqueue_node *next;
514 struct hrtimer *timer;
515
516 next = timerqueue_getnext(&base->active);
517 timer = container_of(next, struct hrtimer, node);
518 if (timer == exclude) {
519 /* Get to the next timer in the queue. */
520 next = timerqueue_iterate_next(next);
521 if (!next)
522 continue;
523
524 timer = container_of(next, struct hrtimer, node);
525 }
526 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
527 if (expires < expires_next) {
528 expires_next = expires;
529
530 /* Skip cpu_base update if a timer is being excluded. */
531 if (exclude)
532 continue;
533
534 if (timer->is_soft)
535 cpu_base->softirq_next_timer = timer;
536 else
537 cpu_base->next_timer = timer;
538 }
539 }
540 /*
541 * clock_was_set() might have changed base->offset of any of
542 * the clock bases so the result might be negative. Fix it up
543 * to prevent a false positive in clockevents_program_event().
544 */
545 if (expires_next < 0)
546 expires_next = 0;
547 return expires_next;
548}
549
550/*
551 * Recomputes cpu_base::*next_timer and returns the earliest expires_next
552 * but does not set cpu_base::*expires_next, that is done by
553 * hrtimer[_force]_reprogram and hrtimer_interrupt only. When updating
554 * cpu_base::*expires_next right away, reprogramming logic would no longer
555 * work.
556 *
557 * When a softirq is pending, we can ignore the HRTIMER_ACTIVE_SOFT bases,
558 * those timers will get run whenever the softirq gets handled, at the end of
559 * hrtimer_run_softirq(), hrtimer_update_softirq_timer() will re-add these bases.
560 *
561 * Therefore softirq values are those from the HRTIMER_ACTIVE_SOFT clock bases.
562 * The !softirq values are the minima across HRTIMER_ACTIVE_ALL, unless an actual
563 * softirq is pending, in which case they're the minima of HRTIMER_ACTIVE_HARD.
564 *
565 * @active_mask must be one of:
566 * - HRTIMER_ACTIVE_ALL,
567 * - HRTIMER_ACTIVE_SOFT, or
568 * - HRTIMER_ACTIVE_HARD.
569 */
570static ktime_t
571__hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_mask)
572{
573 unsigned int active;
574 struct hrtimer *next_timer = NULL;
575 ktime_t expires_next = KTIME_MAX;
576
577 if (!cpu_base->softirq_activated && (active_mask & HRTIMER_ACTIVE_SOFT)) {
578 active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
579 cpu_base->softirq_next_timer = NULL;
580 expires_next = __hrtimer_next_event_base(cpu_base, NULL,
581 active, KTIME_MAX);
582
583 next_timer = cpu_base->softirq_next_timer;
584 }
585
586 if (active_mask & HRTIMER_ACTIVE_HARD) {
587 active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
588 cpu_base->next_timer = next_timer;
589 expires_next = __hrtimer_next_event_base(cpu_base, NULL, active,
590 expires_next);
591 }
592
593 return expires_next;
594}
595
596static ktime_t hrtimer_update_next_event(struct hrtimer_cpu_base *cpu_base)
597{
598 ktime_t expires_next, soft = KTIME_MAX;
599
600 /*
601 * If the soft interrupt has already been activated, ignore the
602 * soft bases. They will be handled in the already raised soft
603 * interrupt.
604 */
605 if (!cpu_base->softirq_activated) {
606 soft = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_SOFT);
607 /*
608 * Update the soft expiry time. clock_settime() might have
609 * affected it.
610 */
611 cpu_base->softirq_expires_next = soft;
612 }
613
614 expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD);
615 /*
616 * If a softirq timer is expiring first, update cpu_base->next_timer
617 * and program the hardware with the soft expiry time.
618 */
619 if (expires_next > soft) {
620 cpu_base->next_timer = cpu_base->softirq_next_timer;
621 expires_next = soft;
622 }
623
624 return expires_next;
625}
626
627static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
628{
629 ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
630 ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
631 ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
632
633 ktime_t now = ktime_get_update_offsets_now(&base->clock_was_set_seq,
634 offs_real, offs_boot, offs_tai);
635
636 base->clock_base[HRTIMER_BASE_REALTIME_SOFT].offset = *offs_real;
637 base->clock_base[HRTIMER_BASE_BOOTTIME_SOFT].offset = *offs_boot;
638 base->clock_base[HRTIMER_BASE_TAI_SOFT].offset = *offs_tai;
639
640 return now;
641}
642
643/*
644 * Is the high resolution mode active ?
645 */
646static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
647{
648 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
649 cpu_base->hres_active : 0;
650}
651
652static inline int hrtimer_hres_active(void)
653{
654 return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
655}
656
657static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base,
658 struct hrtimer *next_timer,
659 ktime_t expires_next)
660{
661 cpu_base->expires_next = expires_next;
662
663 /*
664 * If hres is not active, hardware does not have to be
665 * reprogrammed yet.
666 *
667 * If a hang was detected in the last timer interrupt then we
668 * leave the hang delay active in the hardware. We want the
669 * system to make progress. That also prevents the following
670 * scenario:
671 * T1 expires 50ms from now
672 * T2 expires 5s from now
673 *
674 * T1 is removed, so this code is called and would reprogram
675 * the hardware to 5s from now. Any hrtimer_start after that
676 * will not reprogram the hardware due to hang_detected being
677 * set. So we'd effectively block all timers until the T2 event
678 * fires.
679 */
680 if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
681 return;
682
683 tick_program_event(expires_next, 1);
684}
685
686/*
687 * Reprogram the event source with checking both queues for the
688 * next event
689 * Called with interrupts disabled and base->lock held
690 */
691static void
692hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
693{
694 ktime_t expires_next;
695
696 expires_next = hrtimer_update_next_event(cpu_base);
697
698 if (skip_equal && expires_next == cpu_base->expires_next)
699 return;
700
701 __hrtimer_reprogram(cpu_base, cpu_base->next_timer, expires_next);
702}
703
704/* High resolution timer related functions */
705#ifdef CONFIG_HIGH_RES_TIMERS
706
707/*
708 * High resolution timer enabled ?
709 */
710static bool hrtimer_hres_enabled __read_mostly = true;
711unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
712EXPORT_SYMBOL_GPL(hrtimer_resolution);
713
714/*
715 * Enable / Disable high resolution mode
716 */
717static int __init setup_hrtimer_hres(char *str)
718{
719 return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
720}
721
722__setup("highres=", setup_hrtimer_hres);
723
724/*
725 * hrtimer_high_res_enabled - query, if the highres mode is enabled
726 */
727static inline int hrtimer_is_hres_enabled(void)
728{
729 return hrtimer_hres_enabled;
730}
731
732static void retrigger_next_event(void *arg);
733
734/*
735 * Switch to high resolution mode
736 */
737static void hrtimer_switch_to_hres(void)
738{
739 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
740
741 if (tick_init_highres()) {
742 pr_warn("Could not switch to high resolution mode on CPU %u\n",
743 base->cpu);
744 return;
745 }
746 base->hres_active = 1;
747 hrtimer_resolution = HIGH_RES_NSEC;
748
749 tick_setup_sched_timer();
750 /* "Retrigger" the interrupt to get things going */
751 retrigger_next_event(NULL);
752}
753
754#else
755
756static inline int hrtimer_is_hres_enabled(void) { return 0; }
757static inline void hrtimer_switch_to_hres(void) { }
758
759#endif /* CONFIG_HIGH_RES_TIMERS */
760/*
761 * Retrigger next event is called after clock was set with interrupts
762 * disabled through an SMP function call or directly from low level
763 * resume code.
764 *
765 * This is only invoked when:
766 * - CONFIG_HIGH_RES_TIMERS is enabled.
767 * - CONFIG_NOHZ_COMMON is enabled
768 *
769 * For the other cases this function is empty and because the call sites
770 * are optimized out it vanishes as well, i.e. no need for lots of
771 * #ifdeffery.
772 */
773static void retrigger_next_event(void *arg)
774{
775 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
776
777 /*
778 * When high resolution mode or nohz is active, then the offsets of
779 * CLOCK_REALTIME/TAI/BOOTTIME have to be updated. Otherwise the
780 * next tick will take care of that.
781 *
782 * If high resolution mode is active then the next expiring timer
783 * must be reevaluated and the clock event device reprogrammed if
784 * necessary.
785 *
786 * In the NOHZ case the update of the offset and the reevaluation
787 * of the next expiring timer is enough. The return from the SMP
788 * function call will take care of the reprogramming in case the
789 * CPU was in a NOHZ idle sleep.
790 */
791 if (!__hrtimer_hres_active(base) && !tick_nohz_active)
792 return;
793
794 raw_spin_lock(&base->lock);
795 hrtimer_update_base(base);
796 if (__hrtimer_hres_active(base))
797 hrtimer_force_reprogram(base, 0);
798 else
799 hrtimer_update_next_event(base);
800 raw_spin_unlock(&base->lock);
801}
802
803/*
804 * When a timer is enqueued and expires earlier than the already enqueued
805 * timers, we have to check, whether it expires earlier than the timer for
806 * which the clock event device was armed.
807 *
808 * Called with interrupts disabled and base->cpu_base.lock held
809 */
810static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
811{
812 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
813 struct hrtimer_clock_base *base = timer->base;
814 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
815
816 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
817
818 /*
819 * CLOCK_REALTIME timer might be requested with an absolute
820 * expiry time which is less than base->offset. Set it to 0.
821 */
822 if (expires < 0)
823 expires = 0;
824
825 if (timer->is_soft) {
826 /*
827 * soft hrtimer could be started on a remote CPU. In this
828 * case softirq_expires_next needs to be updated on the
829 * remote CPU. The soft hrtimer will not expire before the
830 * first hard hrtimer on the remote CPU -
831 * hrtimer_check_target() prevents this case.
832 */
833 struct hrtimer_cpu_base *timer_cpu_base = base->cpu_base;
834
835 if (timer_cpu_base->softirq_activated)
836 return;
837
838 if (!ktime_before(expires, timer_cpu_base->softirq_expires_next))
839 return;
840
841 timer_cpu_base->softirq_next_timer = timer;
842 timer_cpu_base->softirq_expires_next = expires;
843
844 if (!ktime_before(expires, timer_cpu_base->expires_next) ||
845 !reprogram)
846 return;
847 }
848
849 /*
850 * If the timer is not on the current cpu, we cannot reprogram
851 * the other cpus clock event device.
852 */
853 if (base->cpu_base != cpu_base)
854 return;
855
856 if (expires >= cpu_base->expires_next)
857 return;
858
859 /*
860 * If the hrtimer interrupt is running, then it will reevaluate the
861 * clock bases and reprogram the clock event device.
862 */
863 if (cpu_base->in_hrtirq)
864 return;
865
866 cpu_base->next_timer = timer;
867
868 __hrtimer_reprogram(cpu_base, timer, expires);
869}
870
871static bool update_needs_ipi(struct hrtimer_cpu_base *cpu_base,
872 unsigned int active)
873{
874 struct hrtimer_clock_base *base;
875 unsigned int seq;
876 ktime_t expires;
877
878 /*
879 * Update the base offsets unconditionally so the following
880 * checks whether the SMP function call is required works.
881 *
882 * The update is safe even when the remote CPU is in the hrtimer
883 * interrupt or the hrtimer soft interrupt and expiring affected
884 * bases. Either it will see the update before handling a base or
885 * it will see it when it finishes the processing and reevaluates
886 * the next expiring timer.
887 */
888 seq = cpu_base->clock_was_set_seq;
889 hrtimer_update_base(cpu_base);
890
891 /*
892 * If the sequence did not change over the update then the
893 * remote CPU already handled it.
894 */
895 if (seq == cpu_base->clock_was_set_seq)
896 return false;
897
898 /*
899 * If the remote CPU is currently handling an hrtimer interrupt, it
900 * will reevaluate the first expiring timer of all clock bases
901 * before reprogramming. Nothing to do here.
902 */
903 if (cpu_base->in_hrtirq)
904 return false;
905
906 /*
907 * Walk the affected clock bases and check whether the first expiring
908 * timer in a clock base is moving ahead of the first expiring timer of
909 * @cpu_base. If so, the IPI must be invoked because per CPU clock
910 * event devices cannot be remotely reprogrammed.
911 */
912 active &= cpu_base->active_bases;
913
914 for_each_active_base(base, cpu_base, active) {
915 struct timerqueue_node *next;
916
917 next = timerqueue_getnext(&base->active);
918 expires = ktime_sub(next->expires, base->offset);
919 if (expires < cpu_base->expires_next)
920 return true;
921
922 /* Extra check for softirq clock bases */
923 if (base->clockid < HRTIMER_BASE_MONOTONIC_SOFT)
924 continue;
925 if (cpu_base->softirq_activated)
926 continue;
927 if (expires < cpu_base->softirq_expires_next)
928 return true;
929 }
930 return false;
931}
932
933/*
934 * Clock was set. This might affect CLOCK_REALTIME, CLOCK_TAI and
935 * CLOCK_BOOTTIME (for late sleep time injection).
936 *
937 * This requires to update the offsets for these clocks
938 * vs. CLOCK_MONOTONIC. When high resolution timers are enabled, then this
939 * also requires to eventually reprogram the per CPU clock event devices
940 * when the change moves an affected timer ahead of the first expiring
941 * timer on that CPU. Obviously remote per CPU clock event devices cannot
942 * be reprogrammed. The other reason why an IPI has to be sent is when the
943 * system is in !HIGH_RES and NOHZ mode. The NOHZ mode updates the offsets
944 * in the tick, which obviously might be stopped, so this has to bring out
945 * the remote CPU which might sleep in idle to get this sorted.
946 */
947void clock_was_set(unsigned int bases)
948{
949 struct hrtimer_cpu_base *cpu_base = raw_cpu_ptr(&hrtimer_bases);
950 cpumask_var_t mask;
951 int cpu;
952
953 if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active)
954 goto out_timerfd;
955
956 if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
957 on_each_cpu(retrigger_next_event, NULL, 1);
958 goto out_timerfd;
959 }
960
961 /* Avoid interrupting CPUs if possible */
962 cpus_read_lock();
963 for_each_online_cpu(cpu) {
964 unsigned long flags;
965
966 cpu_base = &per_cpu(hrtimer_bases, cpu);
967 raw_spin_lock_irqsave(&cpu_base->lock, flags);
968
969 if (update_needs_ipi(cpu_base, bases))
970 cpumask_set_cpu(cpu, mask);
971
972 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
973 }
974
975 preempt_disable();
976 smp_call_function_many(mask, retrigger_next_event, NULL, 1);
977 preempt_enable();
978 cpus_read_unlock();
979 free_cpumask_var(mask);
980
981out_timerfd:
982 timerfd_clock_was_set();
983}
984
985static void clock_was_set_work(struct work_struct *work)
986{
987 clock_was_set(CLOCK_SET_WALL);
988}
989
990static DECLARE_WORK(hrtimer_work, clock_was_set_work);
991
992/*
993 * Called from timekeeping code to reprogram the hrtimer interrupt device
994 * on all cpus and to notify timerfd.
995 */
996void clock_was_set_delayed(void)
997{
998 schedule_work(&hrtimer_work);
999}
1000
1001/*
1002 * Called during resume either directly from via timekeeping_resume()
1003 * or in the case of s2idle from tick_unfreeze() to ensure that the
1004 * hrtimers are up to date.
1005 */
1006void hrtimers_resume_local(void)
1007{
1008 lockdep_assert_irqs_disabled();
1009 /* Retrigger on the local CPU */
1010 retrigger_next_event(NULL);
1011}
1012
1013/*
1014 * Counterpart to lock_hrtimer_base above:
1015 */
1016static inline
1017void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
1018 __releases(&timer->base->cpu_base->lock)
1019{
1020 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
1021}
1022
1023/**
1024 * hrtimer_forward - forward the timer expiry
1025 * @timer: hrtimer to forward
1026 * @now: forward past this time
1027 * @interval: the interval to forward
1028 *
1029 * Forward the timer expiry so it will expire in the future.
1030 * Returns the number of overruns.
1031 *
1032 * Can be safely called from the callback function of @timer. If
1033 * called from other contexts @timer must neither be enqueued nor
1034 * running the callback and the caller needs to take care of
1035 * serialization.
1036 *
1037 * Note: This only updates the timer expiry value and does not requeue
1038 * the timer.
1039 */
1040u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
1041{
1042 u64 orun = 1;
1043 ktime_t delta;
1044
1045 delta = ktime_sub(now, hrtimer_get_expires(timer));
1046
1047 if (delta < 0)
1048 return 0;
1049
1050 if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
1051 return 0;
1052
1053 if (interval < hrtimer_resolution)
1054 interval = hrtimer_resolution;
1055
1056 if (unlikely(delta >= interval)) {
1057 s64 incr = ktime_to_ns(interval);
1058
1059 orun = ktime_divns(delta, incr);
1060 hrtimer_add_expires_ns(timer, incr * orun);
1061 if (hrtimer_get_expires_tv64(timer) > now)
1062 return orun;
1063 /*
1064 * This (and the ktime_add() below) is the
1065 * correction for exact:
1066 */
1067 orun++;
1068 }
1069 hrtimer_add_expires(timer, interval);
1070
1071 return orun;
1072}
1073EXPORT_SYMBOL_GPL(hrtimer_forward);
1074
1075/*
1076 * enqueue_hrtimer - internal function to (re)start a timer
1077 *
1078 * The timer is inserted in expiry order. Insertion into the
1079 * red black tree is O(log(n)). Must hold the base lock.
1080 *
1081 * Returns 1 when the new timer is the leftmost timer in the tree.
1082 */
1083static int enqueue_hrtimer(struct hrtimer *timer,
1084 struct hrtimer_clock_base *base,
1085 enum hrtimer_mode mode)
1086{
1087 debug_activate(timer, mode);
1088 WARN_ON_ONCE(!base->cpu_base->online);
1089
1090 base->cpu_base->active_bases |= 1 << base->index;
1091
1092 /* Pairs with the lockless read in hrtimer_is_queued() */
1093 WRITE_ONCE(timer->state, HRTIMER_STATE_ENQUEUED);
1094
1095 return timerqueue_add(&base->active, &timer->node);
1096}
1097
1098/*
1099 * __remove_hrtimer - internal function to remove a timer
1100 *
1101 * Caller must hold the base lock.
1102 *
1103 * High resolution timer mode reprograms the clock event device when the
1104 * timer is the one which expires next. The caller can disable this by setting
1105 * reprogram to zero. This is useful, when the context does a reprogramming
1106 * anyway (e.g. timer interrupt)
1107 */
1108static void __remove_hrtimer(struct hrtimer *timer,
1109 struct hrtimer_clock_base *base,
1110 u8 newstate, int reprogram)
1111{
1112 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1113 u8 state = timer->state;
1114
1115 /* Pairs with the lockless read in hrtimer_is_queued() */
1116 WRITE_ONCE(timer->state, newstate);
1117 if (!(state & HRTIMER_STATE_ENQUEUED))
1118 return;
1119
1120 if (!timerqueue_del(&base->active, &timer->node))
1121 cpu_base->active_bases &= ~(1 << base->index);
1122
1123 /*
1124 * Note: If reprogram is false we do not update
1125 * cpu_base->next_timer. This happens when we remove the first
1126 * timer on a remote cpu. No harm as we never dereference
1127 * cpu_base->next_timer. So the worst thing what can happen is
1128 * an superfluous call to hrtimer_force_reprogram() on the
1129 * remote cpu later on if the same timer gets enqueued again.
1130 */
1131 if (reprogram && timer == cpu_base->next_timer)
1132 hrtimer_force_reprogram(cpu_base, 1);
1133}
1134
1135/*
1136 * remove hrtimer, called with base lock held
1137 */
1138static inline int
1139remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base,
1140 bool restart, bool keep_local)
1141{
1142 u8 state = timer->state;
1143
1144 if (state & HRTIMER_STATE_ENQUEUED) {
1145 bool reprogram;
1146
1147 /*
1148 * Remove the timer and force reprogramming when high
1149 * resolution mode is active and the timer is on the current
1150 * CPU. If we remove a timer on another CPU, reprogramming is
1151 * skipped. The interrupt event on this CPU is fired and
1152 * reprogramming happens in the interrupt handler. This is a
1153 * rare case and less expensive than a smp call.
1154 */
1155 debug_deactivate(timer);
1156 reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
1157
1158 /*
1159 * If the timer is not restarted then reprogramming is
1160 * required if the timer is local. If it is local and about
1161 * to be restarted, avoid programming it twice (on removal
1162 * and a moment later when it's requeued).
1163 */
1164 if (!restart)
1165 state = HRTIMER_STATE_INACTIVE;
1166 else
1167 reprogram &= !keep_local;
1168
1169 __remove_hrtimer(timer, base, state, reprogram);
1170 return 1;
1171 }
1172 return 0;
1173}
1174
1175static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
1176 const enum hrtimer_mode mode)
1177{
1178#ifdef CONFIG_TIME_LOW_RES
1179 /*
1180 * CONFIG_TIME_LOW_RES indicates that the system has no way to return
1181 * granular time values. For relative timers we add hrtimer_resolution
1182 * (i.e. one jiffie) to prevent short timeouts.
1183 */
1184 timer->is_rel = mode & HRTIMER_MODE_REL;
1185 if (timer->is_rel)
1186 tim = ktime_add_safe(tim, hrtimer_resolution);
1187#endif
1188 return tim;
1189}
1190
1191static void
1192hrtimer_update_softirq_timer(struct hrtimer_cpu_base *cpu_base, bool reprogram)
1193{
1194 ktime_t expires;
1195
1196 /*
1197 * Find the next SOFT expiration.
1198 */
1199 expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_SOFT);
1200
1201 /*
1202 * reprogramming needs to be triggered, even if the next soft
1203 * hrtimer expires at the same time than the next hard
1204 * hrtimer. cpu_base->softirq_expires_next needs to be updated!
1205 */
1206 if (expires == KTIME_MAX)
1207 return;
1208
1209 /*
1210 * cpu_base->*next_timer is recomputed by __hrtimer_get_next_event()
1211 * cpu_base->*expires_next is only set by hrtimer_reprogram()
1212 */
1213 hrtimer_reprogram(cpu_base->softirq_next_timer, reprogram);
1214}
1215
1216static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1217 u64 delta_ns, const enum hrtimer_mode mode,
1218 struct hrtimer_clock_base *base)
1219{
1220 struct hrtimer_clock_base *new_base;
1221 bool force_local, first;
1222
1223 /*
1224 * If the timer is on the local cpu base and is the first expiring
1225 * timer then this might end up reprogramming the hardware twice
1226 * (on removal and on enqueue). To avoid that by prevent the
1227 * reprogram on removal, keep the timer local to the current CPU
1228 * and enforce reprogramming after it is queued no matter whether
1229 * it is the new first expiring timer again or not.
1230 */
1231 force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
1232 force_local &= base->cpu_base->next_timer == timer;
1233
1234 /*
1235 * Remove an active timer from the queue. In case it is not queued
1236 * on the current CPU, make sure that remove_hrtimer() updates the
1237 * remote data correctly.
1238 *
1239 * If it's on the current CPU and the first expiring timer, then
1240 * skip reprogramming, keep the timer local and enforce
1241 * reprogramming later if it was the first expiring timer. This
1242 * avoids programming the underlying clock event twice (once at
1243 * removal and once after enqueue).
1244 */
1245 remove_hrtimer(timer, base, true, force_local);
1246
1247 if (mode & HRTIMER_MODE_REL)
1248 tim = ktime_add_safe(tim, base->get_time());
1249
1250 tim = hrtimer_update_lowres(timer, tim, mode);
1251
1252 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
1253
1254 /* Switch the timer base, if necessary: */
1255 if (!force_local) {
1256 new_base = switch_hrtimer_base(timer, base,
1257 mode & HRTIMER_MODE_PINNED);
1258 } else {
1259 new_base = base;
1260 }
1261
1262 first = enqueue_hrtimer(timer, new_base, mode);
1263 if (!force_local)
1264 return first;
1265
1266 /*
1267 * Timer was forced to stay on the current CPU to avoid
1268 * reprogramming on removal and enqueue. Force reprogram the
1269 * hardware by evaluating the new first expiring timer.
1270 */
1271 hrtimer_force_reprogram(new_base->cpu_base, 1);
1272 return 0;
1273}
1274
1275/**
1276 * hrtimer_start_range_ns - (re)start an hrtimer
1277 * @timer: the timer to be added
1278 * @tim: expiry time
1279 * @delta_ns: "slack" range for the timer
1280 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
1281 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
1282 * softirq based mode is considered for debug purpose only!
1283 */
1284void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1285 u64 delta_ns, const enum hrtimer_mode mode)
1286{
1287 struct hrtimer_clock_base *base;
1288 unsigned long flags;
1289
1290 /*
1291 * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
1292 * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard
1293 * expiry mode because unmarked timers are moved to softirq expiry.
1294 */
1295 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1296 WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);
1297 else
1298 WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard);
1299
1300 base = lock_hrtimer_base(timer, &flags);
1301
1302 if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))
1303 hrtimer_reprogram(timer, true);
1304
1305 unlock_hrtimer_base(timer, &flags);
1306}
1307EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1308
1309/**
1310 * hrtimer_try_to_cancel - try to deactivate a timer
1311 * @timer: hrtimer to stop
1312 *
1313 * Returns:
1314 *
1315 * * 0 when the timer was not active
1316 * * 1 when the timer was active
1317 * * -1 when the timer is currently executing the callback function and
1318 * cannot be stopped
1319 */
1320int hrtimer_try_to_cancel(struct hrtimer *timer)
1321{
1322 struct hrtimer_clock_base *base;
1323 unsigned long flags;
1324 int ret = -1;
1325
1326 /*
1327 * Check lockless first. If the timer is not active (neither
1328 * enqueued nor running the callback, nothing to do here. The
1329 * base lock does not serialize against a concurrent enqueue,
1330 * so we can avoid taking it.
1331 */
1332 if (!hrtimer_active(timer))
1333 return 0;
1334
1335 base = lock_hrtimer_base(timer, &flags);
1336
1337 if (!hrtimer_callback_running(timer))
1338 ret = remove_hrtimer(timer, base, false, false);
1339
1340 unlock_hrtimer_base(timer, &flags);
1341
1342 return ret;
1343
1344}
1345EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1346
1347#ifdef CONFIG_PREEMPT_RT
1348static void hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base)
1349{
1350 spin_lock_init(&base->softirq_expiry_lock);
1351}
1352
1353static void hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base)
1354{
1355 spin_lock(&base->softirq_expiry_lock);
1356}
1357
1358static void hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base)
1359{
1360 spin_unlock(&base->softirq_expiry_lock);
1361}
1362
1363/*
1364 * The counterpart to hrtimer_cancel_wait_running().
1365 *
1366 * If there is a waiter for cpu_base->expiry_lock, then it was waiting for
1367 * the timer callback to finish. Drop expiry_lock and reacquire it. That
1368 * allows the waiter to acquire the lock and make progress.
1369 */
1370static void hrtimer_sync_wait_running(struct hrtimer_cpu_base *cpu_base,
1371 unsigned long flags)
1372{
1373 if (atomic_read(&cpu_base->timer_waiters)) {
1374 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1375 spin_unlock(&cpu_base->softirq_expiry_lock);
1376 spin_lock(&cpu_base->softirq_expiry_lock);
1377 raw_spin_lock_irq(&cpu_base->lock);
1378 }
1379}
1380
1381/*
1382 * This function is called on PREEMPT_RT kernels when the fast path
1383 * deletion of a timer failed because the timer callback function was
1384 * running.
1385 *
1386 * This prevents priority inversion: if the soft irq thread is preempted
1387 * in the middle of a timer callback, then calling del_timer_sync() can
1388 * lead to two issues:
1389 *
1390 * - If the caller is on a remote CPU then it has to spin wait for the timer
1391 * handler to complete. This can result in unbound priority inversion.
1392 *
1393 * - If the caller originates from the task which preempted the timer
1394 * handler on the same CPU, then spin waiting for the timer handler to
1395 * complete is never going to end.
1396 */
1397void hrtimer_cancel_wait_running(const struct hrtimer *timer)
1398{
1399 /* Lockless read. Prevent the compiler from reloading it below */
1400 struct hrtimer_clock_base *base = READ_ONCE(timer->base);
1401
1402 /*
1403 * Just relax if the timer expires in hard interrupt context or if
1404 * it is currently on the migration base.
1405 */
1406 if (!timer->is_soft || is_migration_base(base)) {
1407 cpu_relax();
1408 return;
1409 }
1410
1411 /*
1412 * Mark the base as contended and grab the expiry lock, which is
1413 * held by the softirq across the timer callback. Drop the lock
1414 * immediately so the softirq can expire the next timer. In theory
1415 * the timer could already be running again, but that's more than
1416 * unlikely and just causes another wait loop.
1417 */
1418 atomic_inc(&base->cpu_base->timer_waiters);
1419 spin_lock_bh(&base->cpu_base->softirq_expiry_lock);
1420 atomic_dec(&base->cpu_base->timer_waiters);
1421 spin_unlock_bh(&base->cpu_base->softirq_expiry_lock);
1422}
1423#else
1424static inline void
1425hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base) { }
1426static inline void
1427hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base) { }
1428static inline void
1429hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base) { }
1430static inline void hrtimer_sync_wait_running(struct hrtimer_cpu_base *base,
1431 unsigned long flags) { }
1432#endif
1433
1434/**
1435 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1436 * @timer: the timer to be cancelled
1437 *
1438 * Returns:
1439 * 0 when the timer was not active
1440 * 1 when the timer was active
1441 */
1442int hrtimer_cancel(struct hrtimer *timer)
1443{
1444 int ret;
1445
1446 do {
1447 ret = hrtimer_try_to_cancel(timer);
1448
1449 if (ret < 0)
1450 hrtimer_cancel_wait_running(timer);
1451 } while (ret < 0);
1452 return ret;
1453}
1454EXPORT_SYMBOL_GPL(hrtimer_cancel);
1455
1456/**
1457 * __hrtimer_get_remaining - get remaining time for the timer
1458 * @timer: the timer to read
1459 * @adjust: adjust relative timers when CONFIG_TIME_LOW_RES=y
1460 */
1461ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
1462{
1463 unsigned long flags;
1464 ktime_t rem;
1465
1466 lock_hrtimer_base(timer, &flags);
1467 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
1468 rem = hrtimer_expires_remaining_adjusted(timer);
1469 else
1470 rem = hrtimer_expires_remaining(timer);
1471 unlock_hrtimer_base(timer, &flags);
1472
1473 return rem;
1474}
1475EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
1476
1477#ifdef CONFIG_NO_HZ_COMMON
1478/**
1479 * hrtimer_get_next_event - get the time until next expiry event
1480 *
1481 * Returns the next expiry time or KTIME_MAX if no timer is pending.
1482 */
1483u64 hrtimer_get_next_event(void)
1484{
1485 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1486 u64 expires = KTIME_MAX;
1487 unsigned long flags;
1488
1489 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1490
1491 if (!__hrtimer_hres_active(cpu_base))
1492 expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
1493
1494 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1495
1496 return expires;
1497}
1498
1499/**
1500 * hrtimer_next_event_without - time until next expiry event w/o one timer
1501 * @exclude: timer to exclude
1502 *
1503 * Returns the next expiry time over all timers except for the @exclude one or
1504 * KTIME_MAX if none of them is pending.
1505 */
1506u64 hrtimer_next_event_without(const struct hrtimer *exclude)
1507{
1508 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1509 u64 expires = KTIME_MAX;
1510 unsigned long flags;
1511
1512 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1513
1514 if (__hrtimer_hres_active(cpu_base)) {
1515 unsigned int active;
1516
1517 if (!cpu_base->softirq_activated) {
1518 active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
1519 expires = __hrtimer_next_event_base(cpu_base, exclude,
1520 active, KTIME_MAX);
1521 }
1522 active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
1523 expires = __hrtimer_next_event_base(cpu_base, exclude, active,
1524 expires);
1525 }
1526
1527 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1528
1529 return expires;
1530}
1531#endif
1532
1533static inline int hrtimer_clockid_to_base(clockid_t clock_id)
1534{
1535 if (likely(clock_id < MAX_CLOCKS)) {
1536 int base = hrtimer_clock_to_base_table[clock_id];
1537
1538 if (likely(base != HRTIMER_MAX_CLOCK_BASES))
1539 return base;
1540 }
1541 WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
1542 return HRTIMER_BASE_MONOTONIC;
1543}
1544
1545static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1546 enum hrtimer_mode mode)
1547{
1548 bool softtimer = !!(mode & HRTIMER_MODE_SOFT);
1549 struct hrtimer_cpu_base *cpu_base;
1550 int base;
1551
1552 /*
1553 * On PREEMPT_RT enabled kernels hrtimers which are not explicitly
1554 * marked for hard interrupt expiry mode are moved into soft
1555 * interrupt context for latency reasons and because the callbacks
1556 * can invoke functions which might sleep on RT, e.g. spin_lock().
1557 */
1558 if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(mode & HRTIMER_MODE_HARD))
1559 softtimer = true;
1560
1561 memset(timer, 0, sizeof(struct hrtimer));
1562
1563 cpu_base = raw_cpu_ptr(&hrtimer_bases);
1564
1565 /*
1566 * POSIX magic: Relative CLOCK_REALTIME timers are not affected by
1567 * clock modifications, so they needs to become CLOCK_MONOTONIC to
1568 * ensure POSIX compliance.
1569 */
1570 if (clock_id == CLOCK_REALTIME && mode & HRTIMER_MODE_REL)
1571 clock_id = CLOCK_MONOTONIC;
1572
1573 base = softtimer ? HRTIMER_MAX_CLOCK_BASES / 2 : 0;
1574 base += hrtimer_clockid_to_base(clock_id);
1575 timer->is_soft = softtimer;
1576 timer->is_hard = !!(mode & HRTIMER_MODE_HARD);
1577 timer->base = &cpu_base->clock_base[base];
1578 timerqueue_init(&timer->node);
1579}
1580
1581/**
1582 * hrtimer_init - initialize a timer to the given clock
1583 * @timer: the timer to be initialized
1584 * @clock_id: the clock to be used
1585 * @mode: The modes which are relevant for initialization:
1586 * HRTIMER_MODE_ABS, HRTIMER_MODE_REL, HRTIMER_MODE_ABS_SOFT,
1587 * HRTIMER_MODE_REL_SOFT
1588 *
1589 * The PINNED variants of the above can be handed in,
1590 * but the PINNED bit is ignored as pinning happens
1591 * when the hrtimer is started
1592 */
1593void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1594 enum hrtimer_mode mode)
1595{
1596 debug_init(timer, clock_id, mode);
1597 __hrtimer_init(timer, clock_id, mode);
1598}
1599EXPORT_SYMBOL_GPL(hrtimer_init);
1600
1601/*
1602 * A timer is active, when it is enqueued into the rbtree or the
1603 * callback function is running or it's in the state of being migrated
1604 * to another cpu.
1605 *
1606 * It is important for this function to not return a false negative.
1607 */
1608bool hrtimer_active(const struct hrtimer *timer)
1609{
1610 struct hrtimer_clock_base *base;
1611 unsigned int seq;
1612
1613 do {
1614 base = READ_ONCE(timer->base);
1615 seq = raw_read_seqcount_begin(&base->seq);
1616
1617 if (timer->state != HRTIMER_STATE_INACTIVE ||
1618 base->running == timer)
1619 return true;
1620
1621 } while (read_seqcount_retry(&base->seq, seq) ||
1622 base != READ_ONCE(timer->base));
1623
1624 return false;
1625}
1626EXPORT_SYMBOL_GPL(hrtimer_active);
1627
1628/*
1629 * The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
1630 * distinct sections:
1631 *
1632 * - queued: the timer is queued
1633 * - callback: the timer is being ran
1634 * - post: the timer is inactive or (re)queued
1635 *
1636 * On the read side we ensure we observe timer->state and cpu_base->running
1637 * from the same section, if anything changed while we looked at it, we retry.
1638 * This includes timer->base changing because sequence numbers alone are
1639 * insufficient for that.
1640 *
1641 * The sequence numbers are required because otherwise we could still observe
1642 * a false negative if the read side got smeared over multiple consecutive
1643 * __run_hrtimer() invocations.
1644 */
1645
1646static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
1647 struct hrtimer_clock_base *base,
1648 struct hrtimer *timer, ktime_t *now,
1649 unsigned long flags) __must_hold(&cpu_base->lock)
1650{
1651 enum hrtimer_restart (*fn)(struct hrtimer *);
1652 bool expires_in_hardirq;
1653 int restart;
1654
1655 lockdep_assert_held(&cpu_base->lock);
1656
1657 debug_deactivate(timer);
1658 base->running = timer;
1659
1660 /*
1661 * Separate the ->running assignment from the ->state assignment.
1662 *
1663 * As with a regular write barrier, this ensures the read side in
1664 * hrtimer_active() cannot observe base->running == NULL &&
1665 * timer->state == INACTIVE.
1666 */
1667 raw_write_seqcount_barrier(&base->seq);
1668
1669 __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
1670 fn = timer->function;
1671
1672 /*
1673 * Clear the 'is relative' flag for the TIME_LOW_RES case. If the
1674 * timer is restarted with a period then it becomes an absolute
1675 * timer. If its not restarted it does not matter.
1676 */
1677 if (IS_ENABLED(CONFIG_TIME_LOW_RES))
1678 timer->is_rel = false;
1679
1680 /*
1681 * The timer is marked as running in the CPU base, so it is
1682 * protected against migration to a different CPU even if the lock
1683 * is dropped.
1684 */
1685 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1686 trace_hrtimer_expire_entry(timer, now);
1687 expires_in_hardirq = lockdep_hrtimer_enter(timer);
1688
1689 restart = fn(timer);
1690
1691 lockdep_hrtimer_exit(expires_in_hardirq);
1692 trace_hrtimer_expire_exit(timer);
1693 raw_spin_lock_irq(&cpu_base->lock);
1694
1695 /*
1696 * Note: We clear the running state after enqueue_hrtimer and
1697 * we do not reprogram the event hardware. Happens either in
1698 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1699 *
1700 * Note: Because we dropped the cpu_base->lock above,
1701 * hrtimer_start_range_ns() can have popped in and enqueued the timer
1702 * for us already.
1703 */
1704 if (restart != HRTIMER_NORESTART &&
1705 !(timer->state & HRTIMER_STATE_ENQUEUED))
1706 enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS);
1707
1708 /*
1709 * Separate the ->running assignment from the ->state assignment.
1710 *
1711 * As with a regular write barrier, this ensures the read side in
1712 * hrtimer_active() cannot observe base->running.timer == NULL &&
1713 * timer->state == INACTIVE.
1714 */
1715 raw_write_seqcount_barrier(&base->seq);
1716
1717 WARN_ON_ONCE(base->running != timer);
1718 base->running = NULL;
1719}
1720
1721static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now,
1722 unsigned long flags, unsigned int active_mask)
1723{
1724 struct hrtimer_clock_base *base;
1725 unsigned int active = cpu_base->active_bases & active_mask;
1726
1727 for_each_active_base(base, cpu_base, active) {
1728 struct timerqueue_node *node;
1729 ktime_t basenow;
1730
1731 basenow = ktime_add(now, base->offset);
1732
1733 while ((node = timerqueue_getnext(&base->active))) {
1734 struct hrtimer *timer;
1735
1736 timer = container_of(node, struct hrtimer, node);
1737
1738 /*
1739 * The immediate goal for using the softexpires is
1740 * minimizing wakeups, not running timers at the
1741 * earliest interrupt after their soft expiration.
1742 * This allows us to avoid using a Priority Search
1743 * Tree, which can answer a stabbing query for
1744 * overlapping intervals and instead use the simple
1745 * BST we already have.
1746 * We don't add extra wakeups by delaying timers that
1747 * are right-of a not yet expired timer, because that
1748 * timer will have to trigger a wakeup anyway.
1749 */
1750 if (basenow < hrtimer_get_softexpires_tv64(timer))
1751 break;
1752
1753 __run_hrtimer(cpu_base, base, timer, &basenow, flags);
1754 if (active_mask == HRTIMER_ACTIVE_SOFT)
1755 hrtimer_sync_wait_running(cpu_base, flags);
1756 }
1757 }
1758}
1759
1760static __latent_entropy void hrtimer_run_softirq(struct softirq_action *h)
1761{
1762 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1763 unsigned long flags;
1764 ktime_t now;
1765
1766 hrtimer_cpu_base_lock_expiry(cpu_base);
1767 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1768
1769 now = hrtimer_update_base(cpu_base);
1770 __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_SOFT);
1771
1772 cpu_base->softirq_activated = 0;
1773 hrtimer_update_softirq_timer(cpu_base, true);
1774
1775 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1776 hrtimer_cpu_base_unlock_expiry(cpu_base);
1777}
1778
1779#ifdef CONFIG_HIGH_RES_TIMERS
1780
1781/*
1782 * High resolution timer interrupt
1783 * Called with interrupts disabled
1784 */
1785void hrtimer_interrupt(struct clock_event_device *dev)
1786{
1787 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1788 ktime_t expires_next, now, entry_time, delta;
1789 unsigned long flags;
1790 int retries = 0;
1791
1792 BUG_ON(!cpu_base->hres_active);
1793 cpu_base->nr_events++;
1794 dev->next_event = KTIME_MAX;
1795
1796 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1797 entry_time = now = hrtimer_update_base(cpu_base);
1798retry:
1799 cpu_base->in_hrtirq = 1;
1800 /*
1801 * We set expires_next to KTIME_MAX here with cpu_base->lock
1802 * held to prevent that a timer is enqueued in our queue via
1803 * the migration code. This does not affect enqueueing of
1804 * timers which run their callback and need to be requeued on
1805 * this CPU.
1806 */
1807 cpu_base->expires_next = KTIME_MAX;
1808
1809 if (!ktime_before(now, cpu_base->softirq_expires_next)) {
1810 cpu_base->softirq_expires_next = KTIME_MAX;
1811 cpu_base->softirq_activated = 1;
1812 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1813 }
1814
1815 __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
1816
1817 /* Reevaluate the clock bases for the [soft] next expiry */
1818 expires_next = hrtimer_update_next_event(cpu_base);
1819 /*
1820 * Store the new expiry value so the migration code can verify
1821 * against it.
1822 */
1823 cpu_base->expires_next = expires_next;
1824 cpu_base->in_hrtirq = 0;
1825 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1826
1827 /* Reprogramming necessary ? */
1828 if (!tick_program_event(expires_next, 0)) {
1829 cpu_base->hang_detected = 0;
1830 return;
1831 }
1832
1833 /*
1834 * The next timer was already expired due to:
1835 * - tracing
1836 * - long lasting callbacks
1837 * - being scheduled away when running in a VM
1838 *
1839 * We need to prevent that we loop forever in the hrtimer
1840 * interrupt routine. We give it 3 attempts to avoid
1841 * overreacting on some spurious event.
1842 *
1843 * Acquire base lock for updating the offsets and retrieving
1844 * the current time.
1845 */
1846 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1847 now = hrtimer_update_base(cpu_base);
1848 cpu_base->nr_retries++;
1849 if (++retries < 3)
1850 goto retry;
1851 /*
1852 * Give the system a chance to do something else than looping
1853 * here. We stored the entry time, so we know exactly how long
1854 * we spent here. We schedule the next event this amount of
1855 * time away.
1856 */
1857 cpu_base->nr_hangs++;
1858 cpu_base->hang_detected = 1;
1859 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1860
1861 delta = ktime_sub(now, entry_time);
1862 if ((unsigned int)delta > cpu_base->max_hang_time)
1863 cpu_base->max_hang_time = (unsigned int) delta;
1864 /*
1865 * Limit it to a sensible value as we enforce a longer
1866 * delay. Give the CPU at least 100ms to catch up.
1867 */
1868 if (delta > 100 * NSEC_PER_MSEC)
1869 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1870 else
1871 expires_next = ktime_add(now, delta);
1872 tick_program_event(expires_next, 1);
1873 pr_warn_once("hrtimer: interrupt took %llu ns\n", ktime_to_ns(delta));
1874}
1875
1876/* called with interrupts disabled */
1877static inline void __hrtimer_peek_ahead_timers(void)
1878{
1879 struct tick_device *td;
1880
1881 if (!hrtimer_hres_active())
1882 return;
1883
1884 td = this_cpu_ptr(&tick_cpu_device);
1885 if (td && td->evtdev)
1886 hrtimer_interrupt(td->evtdev);
1887}
1888
1889#else /* CONFIG_HIGH_RES_TIMERS */
1890
1891static inline void __hrtimer_peek_ahead_timers(void) { }
1892
1893#endif /* !CONFIG_HIGH_RES_TIMERS */
1894
1895/*
1896 * Called from run_local_timers in hardirq context every jiffy
1897 */
1898void hrtimer_run_queues(void)
1899{
1900 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1901 unsigned long flags;
1902 ktime_t now;
1903
1904 if (__hrtimer_hres_active(cpu_base))
1905 return;
1906
1907 /*
1908 * This _is_ ugly: We have to check periodically, whether we
1909 * can switch to highres and / or nohz mode. The clocksource
1910 * switch happens with xtime_lock held. Notification from
1911 * there only sets the check bit in the tick_oneshot code,
1912 * otherwise we might deadlock vs. xtime_lock.
1913 */
1914 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
1915 hrtimer_switch_to_hres();
1916 return;
1917 }
1918
1919 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1920 now = hrtimer_update_base(cpu_base);
1921
1922 if (!ktime_before(now, cpu_base->softirq_expires_next)) {
1923 cpu_base->softirq_expires_next = KTIME_MAX;
1924 cpu_base->softirq_activated = 1;
1925 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1926 }
1927
1928 __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
1929 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1930}
1931
1932/*
1933 * Sleep related functions:
1934 */
1935static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1936{
1937 struct hrtimer_sleeper *t =
1938 container_of(timer, struct hrtimer_sleeper, timer);
1939 struct task_struct *task = t->task;
1940
1941 t->task = NULL;
1942 if (task)
1943 wake_up_process(task);
1944
1945 return HRTIMER_NORESTART;
1946}
1947
1948/**
1949 * hrtimer_sleeper_start_expires - Start a hrtimer sleeper timer
1950 * @sl: sleeper to be started
1951 * @mode: timer mode abs/rel
1952 *
1953 * Wrapper around hrtimer_start_expires() for hrtimer_sleeper based timers
1954 * to allow PREEMPT_RT to tweak the delivery mode (soft/hardirq context)
1955 */
1956void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
1957 enum hrtimer_mode mode)
1958{
1959 /*
1960 * Make the enqueue delivery mode check work on RT. If the sleeper
1961 * was initialized for hard interrupt delivery, force the mode bit.
1962 * This is a special case for hrtimer_sleepers because
1963 * hrtimer_init_sleeper() determines the delivery mode on RT so the
1964 * fiddling with this decision is avoided at the call sites.
1965 */
1966 if (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)
1967 mode |= HRTIMER_MODE_HARD;
1968
1969 hrtimer_start_expires(&sl->timer, mode);
1970}
1971EXPORT_SYMBOL_GPL(hrtimer_sleeper_start_expires);
1972
1973static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
1974 clockid_t clock_id, enum hrtimer_mode mode)
1975{
1976 /*
1977 * On PREEMPT_RT enabled kernels hrtimers which are not explicitly
1978 * marked for hard interrupt expiry mode are moved into soft
1979 * interrupt context either for latency reasons or because the
1980 * hrtimer callback takes regular spinlocks or invokes other
1981 * functions which are not suitable for hard interrupt context on
1982 * PREEMPT_RT.
1983 *
1984 * The hrtimer_sleeper callback is RT compatible in hard interrupt
1985 * context, but there is a latency concern: Untrusted userspace can
1986 * spawn many threads which arm timers for the same expiry time on
1987 * the same CPU. That causes a latency spike due to the wakeup of
1988 * a gazillion threads.
1989 *
1990 * OTOH, privileged real-time user space applications rely on the
1991 * low latency of hard interrupt wakeups. If the current task is in
1992 * a real-time scheduling class, mark the mode for hard interrupt
1993 * expiry.
1994 */
1995 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1996 if (task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT))
1997 mode |= HRTIMER_MODE_HARD;
1998 }
1999
2000 __hrtimer_init(&sl->timer, clock_id, mode);
2001 sl->timer.function = hrtimer_wakeup;
2002 sl->task = current;
2003}
2004
2005/**
2006 * hrtimer_init_sleeper - initialize sleeper to the given clock
2007 * @sl: sleeper to be initialized
2008 * @clock_id: the clock to be used
2009 * @mode: timer mode abs/rel
2010 */
2011void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
2012 enum hrtimer_mode mode)
2013{
2014 debug_init(&sl->timer, clock_id, mode);
2015 __hrtimer_init_sleeper(sl, clock_id, mode);
2016
2017}
2018EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
2019
2020int nanosleep_copyout(struct restart_block *restart, struct timespec64 *ts)
2021{
2022 switch(restart->nanosleep.type) {
2023#ifdef CONFIG_COMPAT_32BIT_TIME
2024 case TT_COMPAT:
2025 if (put_old_timespec32(ts, restart->nanosleep.compat_rmtp))
2026 return -EFAULT;
2027 break;
2028#endif
2029 case TT_NATIVE:
2030 if (put_timespec64(ts, restart->nanosleep.rmtp))
2031 return -EFAULT;
2032 break;
2033 default:
2034 BUG();
2035 }
2036 return -ERESTART_RESTARTBLOCK;
2037}
2038
2039static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
2040{
2041 struct restart_block *restart;
2042
2043 do {
2044 set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
2045 hrtimer_sleeper_start_expires(t, mode);
2046
2047 if (likely(t->task))
2048 schedule();
2049
2050 hrtimer_cancel(&t->timer);
2051 mode = HRTIMER_MODE_ABS;
2052
2053 } while (t->task && !signal_pending(current));
2054
2055 __set_current_state(TASK_RUNNING);
2056
2057 if (!t->task)
2058 return 0;
2059
2060 restart = ¤t->restart_block;
2061 if (restart->nanosleep.type != TT_NONE) {
2062 ktime_t rem = hrtimer_expires_remaining(&t->timer);
2063 struct timespec64 rmt;
2064
2065 if (rem <= 0)
2066 return 0;
2067 rmt = ktime_to_timespec64(rem);
2068
2069 return nanosleep_copyout(restart, &rmt);
2070 }
2071 return -ERESTART_RESTARTBLOCK;
2072}
2073
2074static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
2075{
2076 struct hrtimer_sleeper t;
2077 int ret;
2078
2079 hrtimer_init_sleeper_on_stack(&t, restart->nanosleep.clockid,
2080 HRTIMER_MODE_ABS);
2081 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
2082 ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
2083 destroy_hrtimer_on_stack(&t.timer);
2084 return ret;
2085}
2086
2087long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
2088 const clockid_t clockid)
2089{
2090 struct restart_block *restart;
2091 struct hrtimer_sleeper t;
2092 int ret = 0;
2093 u64 slack;
2094
2095 slack = current->timer_slack_ns;
2096 if (rt_task(current))
2097 slack = 0;
2098
2099 hrtimer_init_sleeper_on_stack(&t, clockid, mode);
2100 hrtimer_set_expires_range_ns(&t.timer, rqtp, slack);
2101 ret = do_nanosleep(&t, mode);
2102 if (ret != -ERESTART_RESTARTBLOCK)
2103 goto out;
2104
2105 /* Absolute timers do not update the rmtp value and restart: */
2106 if (mode == HRTIMER_MODE_ABS) {
2107 ret = -ERESTARTNOHAND;
2108 goto out;
2109 }
2110
2111 restart = ¤t->restart_block;
2112 restart->nanosleep.clockid = t.timer.base->clockid;
2113 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
2114 set_restart_fn(restart, hrtimer_nanosleep_restart);
2115out:
2116 destroy_hrtimer_on_stack(&t.timer);
2117 return ret;
2118}
2119
2120#ifdef CONFIG_64BIT
2121
2122SYSCALL_DEFINE2(nanosleep, struct __kernel_timespec __user *, rqtp,
2123 struct __kernel_timespec __user *, rmtp)
2124{
2125 struct timespec64 tu;
2126
2127 if (get_timespec64(&tu, rqtp))
2128 return -EFAULT;
2129
2130 if (!timespec64_valid(&tu))
2131 return -EINVAL;
2132
2133 current->restart_block.fn = do_no_restart_syscall;
2134 current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
2135 current->restart_block.nanosleep.rmtp = rmtp;
2136 return hrtimer_nanosleep(timespec64_to_ktime(tu), HRTIMER_MODE_REL,
2137 CLOCK_MONOTONIC);
2138}
2139
2140#endif
2141
2142#ifdef CONFIG_COMPAT_32BIT_TIME
2143
2144SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp,
2145 struct old_timespec32 __user *, rmtp)
2146{
2147 struct timespec64 tu;
2148
2149 if (get_old_timespec32(&tu, rqtp))
2150 return -EFAULT;
2151
2152 if (!timespec64_valid(&tu))
2153 return -EINVAL;
2154
2155 current->restart_block.fn = do_no_restart_syscall;
2156 current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
2157 current->restart_block.nanosleep.compat_rmtp = rmtp;
2158 return hrtimer_nanosleep(timespec64_to_ktime(tu), HRTIMER_MODE_REL,
2159 CLOCK_MONOTONIC);
2160}
2161#endif
2162
2163/*
2164 * Functions related to boot-time initialization:
2165 */
2166int hrtimers_prepare_cpu(unsigned int cpu)
2167{
2168 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
2169 int i;
2170
2171 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
2172 struct hrtimer_clock_base *clock_b = &cpu_base->clock_base[i];
2173
2174 clock_b->cpu_base = cpu_base;
2175 seqcount_raw_spinlock_init(&clock_b->seq, &cpu_base->lock);
2176 timerqueue_init_head(&clock_b->active);
2177 }
2178
2179 cpu_base->cpu = cpu;
2180 cpu_base->active_bases = 0;
2181 cpu_base->hres_active = 0;
2182 cpu_base->hang_detected = 0;
2183 cpu_base->next_timer = NULL;
2184 cpu_base->softirq_next_timer = NULL;
2185 cpu_base->expires_next = KTIME_MAX;
2186 cpu_base->softirq_expires_next = KTIME_MAX;
2187 cpu_base->online = 1;
2188 hrtimer_cpu_base_init_expiry_lock(cpu_base);
2189 return 0;
2190}
2191
2192#ifdef CONFIG_HOTPLUG_CPU
2193
2194static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
2195 struct hrtimer_clock_base *new_base)
2196{
2197 struct hrtimer *timer;
2198 struct timerqueue_node *node;
2199
2200 while ((node = timerqueue_getnext(&old_base->active))) {
2201 timer = container_of(node, struct hrtimer, node);
2202 BUG_ON(hrtimer_callback_running(timer));
2203 debug_deactivate(timer);
2204
2205 /*
2206 * Mark it as ENQUEUED not INACTIVE otherwise the
2207 * timer could be seen as !active and just vanish away
2208 * under us on another CPU
2209 */
2210 __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
2211 timer->base = new_base;
2212 /*
2213 * Enqueue the timers on the new cpu. This does not
2214 * reprogram the event device in case the timer
2215 * expires before the earliest on this CPU, but we run
2216 * hrtimer_interrupt after we migrated everything to
2217 * sort out already expired timers and reprogram the
2218 * event device.
2219 */
2220 enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);
2221 }
2222}
2223
2224int hrtimers_cpu_dying(unsigned int dying_cpu)
2225{
2226 struct hrtimer_cpu_base *old_base, *new_base;
2227 int i, ncpu = cpumask_first(cpu_active_mask);
2228
2229 tick_cancel_sched_timer(dying_cpu);
2230
2231 old_base = this_cpu_ptr(&hrtimer_bases);
2232 new_base = &per_cpu(hrtimer_bases, ncpu);
2233
2234 /*
2235 * The caller is globally serialized and nobody else
2236 * takes two locks at once, deadlock is not possible.
2237 */
2238 raw_spin_lock(&old_base->lock);
2239 raw_spin_lock_nested(&new_base->lock, SINGLE_DEPTH_NESTING);
2240
2241 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
2242 migrate_hrtimer_list(&old_base->clock_base[i],
2243 &new_base->clock_base[i]);
2244 }
2245
2246 /*
2247 * The migration might have changed the first expiring softirq
2248 * timer on this CPU. Update it.
2249 */
2250 __hrtimer_get_next_event(new_base, HRTIMER_ACTIVE_SOFT);
2251 /* Tell the other CPU to retrigger the next event */
2252 smp_call_function_single(ncpu, retrigger_next_event, NULL, 0);
2253
2254 raw_spin_unlock(&new_base->lock);
2255 old_base->online = 0;
2256 raw_spin_unlock(&old_base->lock);
2257
2258 return 0;
2259}
2260
2261#endif /* CONFIG_HOTPLUG_CPU */
2262
2263void __init hrtimers_init(void)
2264{
2265 hrtimers_prepare_cpu(smp_processor_id());
2266 open_softirq(HRTIMER_SOFTIRQ, hrtimer_run_softirq);
2267}
2268
2269/**
2270 * schedule_hrtimeout_range_clock - sleep until timeout
2271 * @expires: timeout value (ktime_t)
2272 * @delta: slack in expires timeout (ktime_t) for SCHED_OTHER tasks
2273 * @mode: timer mode
2274 * @clock_id: timer clock to be used
2275 */
2276int __sched
2277schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
2278 const enum hrtimer_mode mode, clockid_t clock_id)
2279{
2280 struct hrtimer_sleeper t;
2281
2282 /*
2283 * Optimize when a zero timeout value is given. It does not
2284 * matter whether this is an absolute or a relative time.
2285 */
2286 if (expires && *expires == 0) {
2287 __set_current_state(TASK_RUNNING);
2288 return 0;
2289 }
2290
2291 /*
2292 * A NULL parameter means "infinite"
2293 */
2294 if (!expires) {
2295 schedule();
2296 return -EINTR;
2297 }
2298
2299 /*
2300 * Override any slack passed by the user if under
2301 * rt contraints.
2302 */
2303 if (rt_task(current))
2304 delta = 0;
2305
2306 hrtimer_init_sleeper_on_stack(&t, clock_id, mode);
2307 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
2308 hrtimer_sleeper_start_expires(&t, mode);
2309
2310 if (likely(t.task))
2311 schedule();
2312
2313 hrtimer_cancel(&t.timer);
2314 destroy_hrtimer_on_stack(&t.timer);
2315
2316 __set_current_state(TASK_RUNNING);
2317
2318 return !t.task ? 0 : -EINTR;
2319}
2320EXPORT_SYMBOL_GPL(schedule_hrtimeout_range_clock);
2321
2322/**
2323 * schedule_hrtimeout_range - sleep until timeout
2324 * @expires: timeout value (ktime_t)
2325 * @delta: slack in expires timeout (ktime_t) for SCHED_OTHER tasks
2326 * @mode: timer mode
2327 *
2328 * Make the current task sleep until the given expiry time has
2329 * elapsed. The routine will return immediately unless
2330 * the current task state has been set (see set_current_state()).
2331 *
2332 * The @delta argument gives the kernel the freedom to schedule the
2333 * actual wakeup to a time that is both power and performance friendly
2334 * for regular (non RT/DL) tasks.
2335 * The kernel give the normal best effort behavior for "@expires+@delta",
2336 * but may decide to fire the timer earlier, but no earlier than @expires.
2337 *
2338 * You can set the task state as follows -
2339 *
2340 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
2341 * pass before the routine returns unless the current task is explicitly
2342 * woken up, (e.g. by wake_up_process()).
2343 *
2344 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
2345 * delivered to the current task or the current task is explicitly woken
2346 * up.
2347 *
2348 * The current task state is guaranteed to be TASK_RUNNING when this
2349 * routine returns.
2350 *
2351 * Returns 0 when the timer has expired. If the task was woken before the
2352 * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
2353 * by an explicit wakeup, it returns -EINTR.
2354 */
2355int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
2356 const enum hrtimer_mode mode)
2357{
2358 return schedule_hrtimeout_range_clock(expires, delta, mode,
2359 CLOCK_MONOTONIC);
2360}
2361EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
2362
2363/**
2364 * schedule_hrtimeout - sleep until timeout
2365 * @expires: timeout value (ktime_t)
2366 * @mode: timer mode
2367 *
2368 * Make the current task sleep until the given expiry time has
2369 * elapsed. The routine will return immediately unless
2370 * the current task state has been set (see set_current_state()).
2371 *
2372 * You can set the task state as follows -
2373 *
2374 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
2375 * pass before the routine returns unless the current task is explicitly
2376 * woken up, (e.g. by wake_up_process()).
2377 *
2378 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
2379 * delivered to the current task or the current task is explicitly woken
2380 * up.
2381 *
2382 * The current task state is guaranteed to be TASK_RUNNING when this
2383 * routine returns.
2384 *
2385 * Returns 0 when the timer has expired. If the task was woken before the
2386 * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
2387 * by an explicit wakeup, it returns -EINTR.
2388 */
2389int __sched schedule_hrtimeout(ktime_t *expires,
2390 const enum hrtimer_mode mode)
2391{
2392 return schedule_hrtimeout_range(expires, 0, mode);
2393}
2394EXPORT_SYMBOL_GPL(schedule_hrtimeout);