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15#include <linux/time.h>
16#include <linux/hrtimer.h>
17#include <linux/timerqueue.h>
18#include <linux/rtc.h>
19#include <linux/sched/signal.h>
20#include <linux/sched/debug.h>
21#include <linux/alarmtimer.h>
22#include <linux/mutex.h>
23#include <linux/platform_device.h>
24#include <linux/posix-timers.h>
25#include <linux/workqueue.h>
26#include <linux/freezer.h>
27#include <linux/compat.h>
28#include <linux/module.h>
29
30#include "posix-timers.h"
31
32#define CREATE_TRACE_POINTS
33#include <trace/events/alarmtimer.h>
34
35
36
37
38
39
40
41
42static struct alarm_base {
43 spinlock_t lock;
44 struct timerqueue_head timerqueue;
45 ktime_t (*gettime)(void);
46 clockid_t base_clockid;
47} alarm_bases[ALARM_NUMTYPE];
48
49#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
50
51static enum alarmtimer_type freezer_alarmtype;
52static ktime_t freezer_expires;
53static ktime_t freezer_delta;
54static DEFINE_SPINLOCK(freezer_delta_lock);
55#endif
56
57#ifdef CONFIG_RTC_CLASS
58static struct wakeup_source *ws;
59
60
61static struct rtc_timer rtctimer;
62static struct rtc_device *rtcdev;
63static DEFINE_SPINLOCK(rtcdev_lock);
64
65
66
67
68
69
70
71
72struct rtc_device *alarmtimer_get_rtcdev(void)
73{
74 unsigned long flags;
75 struct rtc_device *ret;
76
77 spin_lock_irqsave(&rtcdev_lock, flags);
78 ret = rtcdev;
79 spin_unlock_irqrestore(&rtcdev_lock, flags);
80
81 return ret;
82}
83EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
84
85static int alarmtimer_rtc_add_device(struct device *dev,
86 struct class_interface *class_intf)
87{
88 unsigned long flags;
89 struct rtc_device *rtc = to_rtc_device(dev);
90 struct wakeup_source *__ws;
91
92 if (rtcdev)
93 return -EBUSY;
94
95 if (!rtc->ops->set_alarm)
96 return -1;
97 if (!device_may_wakeup(rtc->dev.parent))
98 return -1;
99
100 __ws = wakeup_source_register("alarmtimer");
101
102 spin_lock_irqsave(&rtcdev_lock, flags);
103 if (!rtcdev) {
104 if (!try_module_get(rtc->owner)) {
105 spin_unlock_irqrestore(&rtcdev_lock, flags);
106 return -1;
107 }
108
109 rtcdev = rtc;
110
111 get_device(dev);
112 ws = __ws;
113 __ws = NULL;
114 }
115 spin_unlock_irqrestore(&rtcdev_lock, flags);
116
117 wakeup_source_unregister(__ws);
118
119 return 0;
120}
121
122static inline void alarmtimer_rtc_timer_init(void)
123{
124 rtc_timer_init(&rtctimer, NULL, NULL);
125}
126
127static struct class_interface alarmtimer_rtc_interface = {
128 .add_dev = &alarmtimer_rtc_add_device,
129};
130
131static int alarmtimer_rtc_interface_setup(void)
132{
133 alarmtimer_rtc_interface.class = rtc_class;
134 return class_interface_register(&alarmtimer_rtc_interface);
135}
136static void alarmtimer_rtc_interface_remove(void)
137{
138 class_interface_unregister(&alarmtimer_rtc_interface);
139}
140#else
141struct rtc_device *alarmtimer_get_rtcdev(void)
142{
143 return NULL;
144}
145#define rtcdev (NULL)
146static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
147static inline void alarmtimer_rtc_interface_remove(void) { }
148static inline void alarmtimer_rtc_timer_init(void) { }
149#endif
150
151
152
153
154
155
156
157
158
159
160static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
161{
162 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
163 timerqueue_del(&base->timerqueue, &alarm->node);
164
165 timerqueue_add(&base->timerqueue, &alarm->node);
166 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
167}
168
169
170
171
172
173
174
175
176
177
178static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
179{
180 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
181 return;
182
183 timerqueue_del(&base->timerqueue, &alarm->node);
184 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
185}
186
187
188
189
190
191
192
193
194
195
196
197static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
198{
199 struct alarm *alarm = container_of(timer, struct alarm, timer);
200 struct alarm_base *base = &alarm_bases[alarm->type];
201 unsigned long flags;
202 int ret = HRTIMER_NORESTART;
203 int restart = ALARMTIMER_NORESTART;
204
205 spin_lock_irqsave(&base->lock, flags);
206 alarmtimer_dequeue(base, alarm);
207 spin_unlock_irqrestore(&base->lock, flags);
208
209 if (alarm->function)
210 restart = alarm->function(alarm, base->gettime());
211
212 spin_lock_irqsave(&base->lock, flags);
213 if (restart != ALARMTIMER_NORESTART) {
214 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
215 alarmtimer_enqueue(base, alarm);
216 ret = HRTIMER_RESTART;
217 }
218 spin_unlock_irqrestore(&base->lock, flags);
219
220 trace_alarmtimer_fired(alarm, base->gettime());
221 return ret;
222
223}
224
225ktime_t alarm_expires_remaining(const struct alarm *alarm)
226{
227 struct alarm_base *base = &alarm_bases[alarm->type];
228 return ktime_sub(alarm->node.expires, base->gettime());
229}
230EXPORT_SYMBOL_GPL(alarm_expires_remaining);
231
232#ifdef CONFIG_RTC_CLASS
233
234
235
236
237
238
239
240
241
242static int alarmtimer_suspend(struct device *dev)
243{
244 ktime_t min, now, expires;
245 int i, ret, type;
246 struct rtc_device *rtc;
247 unsigned long flags;
248 struct rtc_time tm;
249
250 spin_lock_irqsave(&freezer_delta_lock, flags);
251 min = freezer_delta;
252 expires = freezer_expires;
253 type = freezer_alarmtype;
254 freezer_delta = 0;
255 spin_unlock_irqrestore(&freezer_delta_lock, flags);
256
257 rtc = alarmtimer_get_rtcdev();
258
259 if (!rtc)
260 return 0;
261
262
263 for (i = 0; i < ALARM_NUMTYPE; i++) {
264 struct alarm_base *base = &alarm_bases[i];
265 struct timerqueue_node *next;
266 ktime_t delta;
267
268 spin_lock_irqsave(&base->lock, flags);
269 next = timerqueue_getnext(&base->timerqueue);
270 spin_unlock_irqrestore(&base->lock, flags);
271 if (!next)
272 continue;
273 delta = ktime_sub(next->expires, base->gettime());
274 if (!min || (delta < min)) {
275 expires = next->expires;
276 min = delta;
277 type = i;
278 }
279 }
280 if (min == 0)
281 return 0;
282
283 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
284 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
285 return -EBUSY;
286 }
287
288 trace_alarmtimer_suspend(expires, type);
289
290
291 rtc_timer_cancel(rtc, &rtctimer);
292 rtc_read_time(rtc, &tm);
293 now = rtc_tm_to_ktime(tm);
294 now = ktime_add(now, min);
295
296
297 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
298 if (ret < 0)
299 __pm_wakeup_event(ws, MSEC_PER_SEC);
300 return ret;
301}
302
303static int alarmtimer_resume(struct device *dev)
304{
305 struct rtc_device *rtc;
306
307 rtc = alarmtimer_get_rtcdev();
308 if (rtc)
309 rtc_timer_cancel(rtc, &rtctimer);
310 return 0;
311}
312
313#else
314static int alarmtimer_suspend(struct device *dev)
315{
316 return 0;
317}
318
319static int alarmtimer_resume(struct device *dev)
320{
321 return 0;
322}
323#endif
324
325static void
326__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
327 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
328{
329 timerqueue_init(&alarm->node);
330 alarm->timer.function = alarmtimer_fired;
331 alarm->function = function;
332 alarm->type = type;
333 alarm->state = ALARMTIMER_STATE_INACTIVE;
334}
335
336
337
338
339
340
341
342void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
343 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
344{
345 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
346 HRTIMER_MODE_ABS);
347 __alarm_init(alarm, type, function);
348}
349EXPORT_SYMBOL_GPL(alarm_init);
350
351
352
353
354
355
356void alarm_start(struct alarm *alarm, ktime_t start)
357{
358 struct alarm_base *base = &alarm_bases[alarm->type];
359 unsigned long flags;
360
361 spin_lock_irqsave(&base->lock, flags);
362 alarm->node.expires = start;
363 alarmtimer_enqueue(base, alarm);
364 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
365 spin_unlock_irqrestore(&base->lock, flags);
366
367 trace_alarmtimer_start(alarm, base->gettime());
368}
369EXPORT_SYMBOL_GPL(alarm_start);
370
371
372
373
374
375
376void alarm_start_relative(struct alarm *alarm, ktime_t start)
377{
378 struct alarm_base *base = &alarm_bases[alarm->type];
379
380 start = ktime_add_safe(start, base->gettime());
381 alarm_start(alarm, start);
382}
383EXPORT_SYMBOL_GPL(alarm_start_relative);
384
385void alarm_restart(struct alarm *alarm)
386{
387 struct alarm_base *base = &alarm_bases[alarm->type];
388 unsigned long flags;
389
390 spin_lock_irqsave(&base->lock, flags);
391 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
392 hrtimer_restart(&alarm->timer);
393 alarmtimer_enqueue(base, alarm);
394 spin_unlock_irqrestore(&base->lock, flags);
395}
396EXPORT_SYMBOL_GPL(alarm_restart);
397
398
399
400
401
402
403
404
405int alarm_try_to_cancel(struct alarm *alarm)
406{
407 struct alarm_base *base = &alarm_bases[alarm->type];
408 unsigned long flags;
409 int ret;
410
411 spin_lock_irqsave(&base->lock, flags);
412 ret = hrtimer_try_to_cancel(&alarm->timer);
413 if (ret >= 0)
414 alarmtimer_dequeue(base, alarm);
415 spin_unlock_irqrestore(&base->lock, flags);
416
417 trace_alarmtimer_cancel(alarm, base->gettime());
418 return ret;
419}
420EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
421
422
423
424
425
426
427
428
429int alarm_cancel(struct alarm *alarm)
430{
431 for (;;) {
432 int ret = alarm_try_to_cancel(alarm);
433 if (ret >= 0)
434 return ret;
435 cpu_relax();
436 }
437}
438EXPORT_SYMBOL_GPL(alarm_cancel);
439
440
441u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
442{
443 u64 overrun = 1;
444 ktime_t delta;
445
446 delta = ktime_sub(now, alarm->node.expires);
447
448 if (delta < 0)
449 return 0;
450
451 if (unlikely(delta >= interval)) {
452 s64 incr = ktime_to_ns(interval);
453
454 overrun = ktime_divns(delta, incr);
455
456 alarm->node.expires = ktime_add_ns(alarm->node.expires,
457 incr*overrun);
458
459 if (alarm->node.expires > now)
460 return overrun;
461
462
463
464
465 overrun++;
466 }
467
468 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
469 return overrun;
470}
471EXPORT_SYMBOL_GPL(alarm_forward);
472
473u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
474{
475 struct alarm_base *base = &alarm_bases[alarm->type];
476
477 return alarm_forward(alarm, base->gettime(), interval);
478}
479EXPORT_SYMBOL_GPL(alarm_forward_now);
480
481#ifdef CONFIG_POSIX_TIMERS
482
483static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
484{
485 struct alarm_base *base;
486 unsigned long flags;
487 ktime_t delta;
488
489 switch(type) {
490 case ALARM_REALTIME:
491 base = &alarm_bases[ALARM_REALTIME];
492 type = ALARM_REALTIME_FREEZER;
493 break;
494 case ALARM_BOOTTIME:
495 base = &alarm_bases[ALARM_BOOTTIME];
496 type = ALARM_BOOTTIME_FREEZER;
497 break;
498 default:
499 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
500 return;
501 }
502
503 delta = ktime_sub(absexp, base->gettime());
504
505 spin_lock_irqsave(&freezer_delta_lock, flags);
506 if (!freezer_delta || (delta < freezer_delta)) {
507 freezer_delta = delta;
508 freezer_expires = absexp;
509 freezer_alarmtype = type;
510 }
511 spin_unlock_irqrestore(&freezer_delta_lock, flags);
512}
513
514
515
516
517
518static enum alarmtimer_type clock2alarm(clockid_t clockid)
519{
520 if (clockid == CLOCK_REALTIME_ALARM)
521 return ALARM_REALTIME;
522 if (clockid == CLOCK_BOOTTIME_ALARM)
523 return ALARM_BOOTTIME;
524 return -1;
525}
526
527
528
529
530
531
532
533static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
534 ktime_t now)
535{
536 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
537 it.alarm.alarmtimer);
538 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
539 unsigned long flags;
540 int si_private = 0;
541
542 spin_lock_irqsave(&ptr->it_lock, flags);
543
544 ptr->it_active = 0;
545 if (ptr->it_interval)
546 si_private = ++ptr->it_requeue_pending;
547
548 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
549
550
551
552
553 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
554 ++ptr->it_requeue_pending;
555 ptr->it_active = 1;
556 result = ALARMTIMER_RESTART;
557 }
558 spin_unlock_irqrestore(&ptr->it_lock, flags);
559
560 return result;
561}
562
563
564
565
566
567static void alarm_timer_rearm(struct k_itimer *timr)
568{
569 struct alarm *alarm = &timr->it.alarm.alarmtimer;
570
571 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
572 alarm_start(alarm, alarm->node.expires);
573}
574
575
576
577
578
579
580static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
581{
582 struct alarm *alarm = &timr->it.alarm.alarmtimer;
583
584 return alarm_forward(alarm, timr->it_interval, now);
585}
586
587
588
589
590
591
592static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
593{
594 struct alarm *alarm = &timr->it.alarm.alarmtimer;
595
596 return ktime_sub(alarm->node.expires, now);
597}
598
599
600
601
602
603static int alarm_timer_try_to_cancel(struct k_itimer *timr)
604{
605 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
606}
607
608
609
610
611
612
613
614
615static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
616 bool absolute, bool sigev_none)
617{
618 struct alarm *alarm = &timr->it.alarm.alarmtimer;
619 struct alarm_base *base = &alarm_bases[alarm->type];
620
621 if (!absolute)
622 expires = ktime_add_safe(expires, base->gettime());
623 if (sigev_none)
624 alarm->node.expires = expires;
625 else
626 alarm_start(&timr->it.alarm.alarmtimer, expires);
627}
628
629
630
631
632
633
634
635
636static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
637{
638 if (!alarmtimer_get_rtcdev())
639 return -EINVAL;
640
641 tp->tv_sec = 0;
642 tp->tv_nsec = hrtimer_resolution;
643 return 0;
644}
645
646
647
648
649
650
651
652
653static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
654{
655 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
656
657 if (!alarmtimer_get_rtcdev())
658 return -EINVAL;
659
660 *tp = ktime_to_timespec64(base->gettime());
661 return 0;
662}
663
664
665
666
667
668
669
670static int alarm_timer_create(struct k_itimer *new_timer)
671{
672 enum alarmtimer_type type;
673
674 if (!alarmtimer_get_rtcdev())
675 return -ENOTSUPP;
676
677 if (!capable(CAP_WAKE_ALARM))
678 return -EPERM;
679
680 type = clock2alarm(new_timer->it_clock);
681 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
682 return 0;
683}
684
685
686
687
688
689
690
691static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
692 ktime_t now)
693{
694 struct task_struct *task = (struct task_struct *)alarm->data;
695
696 alarm->data = NULL;
697 if (task)
698 wake_up_process(task);
699 return ALARMTIMER_NORESTART;
700}
701
702
703
704
705
706
707
708
709static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
710 enum alarmtimer_type type)
711{
712 struct restart_block *restart;
713 alarm->data = (void *)current;
714 do {
715 set_current_state(TASK_INTERRUPTIBLE);
716 alarm_start(alarm, absexp);
717 if (likely(alarm->data))
718 schedule();
719
720 alarm_cancel(alarm);
721 } while (alarm->data && !signal_pending(current));
722
723 __set_current_state(TASK_RUNNING);
724
725 destroy_hrtimer_on_stack(&alarm->timer);
726
727 if (!alarm->data)
728 return 0;
729
730 if (freezing(current))
731 alarmtimer_freezerset(absexp, type);
732 restart = ¤t->restart_block;
733 if (restart->nanosleep.type != TT_NONE) {
734 struct timespec64 rmt;
735 ktime_t rem;
736
737 rem = ktime_sub(absexp, alarm_bases[type].gettime());
738
739 if (rem <= 0)
740 return 0;
741 rmt = ktime_to_timespec64(rem);
742
743 return nanosleep_copyout(restart, &rmt);
744 }
745 return -ERESTART_RESTARTBLOCK;
746}
747
748static void
749alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
750 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
751{
752 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
753 HRTIMER_MODE_ABS);
754 __alarm_init(alarm, type, function);
755}
756
757
758
759
760
761
762
763static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
764{
765 enum alarmtimer_type type = restart->nanosleep.clockid;
766 ktime_t exp = restart->nanosleep.expires;
767 struct alarm alarm;
768
769 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
770
771 return alarmtimer_do_nsleep(&alarm, exp, type);
772}
773
774
775
776
777
778
779
780
781
782
783static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
784 const struct timespec64 *tsreq)
785{
786 enum alarmtimer_type type = clock2alarm(which_clock);
787 struct restart_block *restart = ¤t->restart_block;
788 struct alarm alarm;
789 ktime_t exp;
790 int ret = 0;
791
792 if (!alarmtimer_get_rtcdev())
793 return -ENOTSUPP;
794
795 if (flags & ~TIMER_ABSTIME)
796 return -EINVAL;
797
798 if (!capable(CAP_WAKE_ALARM))
799 return -EPERM;
800
801 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
802
803 exp = timespec64_to_ktime(*tsreq);
804
805 if (flags != TIMER_ABSTIME) {
806 ktime_t now = alarm_bases[type].gettime();
807
808 exp = ktime_add_safe(now, exp);
809 }
810
811 ret = alarmtimer_do_nsleep(&alarm, exp, type);
812 if (ret != -ERESTART_RESTARTBLOCK)
813 return ret;
814
815
816 if (flags == TIMER_ABSTIME)
817 return -ERESTARTNOHAND;
818
819 restart->fn = alarm_timer_nsleep_restart;
820 restart->nanosleep.clockid = type;
821 restart->nanosleep.expires = exp;
822 return ret;
823}
824
825const struct k_clock alarm_clock = {
826 .clock_getres = alarm_clock_getres,
827 .clock_get = alarm_clock_get,
828 .timer_create = alarm_timer_create,
829 .timer_set = common_timer_set,
830 .timer_del = common_timer_del,
831 .timer_get = common_timer_get,
832 .timer_arm = alarm_timer_arm,
833 .timer_rearm = alarm_timer_rearm,
834 .timer_forward = alarm_timer_forward,
835 .timer_remaining = alarm_timer_remaining,
836 .timer_try_to_cancel = alarm_timer_try_to_cancel,
837 .nsleep = alarm_timer_nsleep,
838};
839#endif
840
841
842
843static const struct dev_pm_ops alarmtimer_pm_ops = {
844 .suspend = alarmtimer_suspend,
845 .resume = alarmtimer_resume,
846};
847
848static struct platform_driver alarmtimer_driver = {
849 .driver = {
850 .name = "alarmtimer",
851 .pm = &alarmtimer_pm_ops,
852 }
853};
854
855
856
857
858
859
860
861static int __init alarmtimer_init(void)
862{
863 struct platform_device *pdev;
864 int error = 0;
865 int i;
866
867 alarmtimer_rtc_timer_init();
868
869
870 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
871 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
872 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
873 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
874 for (i = 0; i < ALARM_NUMTYPE; i++) {
875 timerqueue_init_head(&alarm_bases[i].timerqueue);
876 spin_lock_init(&alarm_bases[i].lock);
877 }
878
879 error = alarmtimer_rtc_interface_setup();
880 if (error)
881 return error;
882
883 error = platform_driver_register(&alarmtimer_driver);
884 if (error)
885 goto out_if;
886
887 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
888 if (IS_ERR(pdev)) {
889 error = PTR_ERR(pdev);
890 goto out_drv;
891 }
892 return 0;
893
894out_drv:
895 platform_driver_unregister(&alarmtimer_driver);
896out_if:
897 alarmtimer_rtc_interface_remove();
898 return error;
899}
900device_initcall(alarmtimer_init);
901