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1/*
2 * Alarmtimer interface
3 *
4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
6 *
7 * This interface is influenced by the Android RTC Alarm timer
8 * interface.
9 *
10 * Copyright (C) 2010 IBM Corperation
11 *
12 * Author: John Stultz <john.stultz@linaro.org>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18#include <linux/time.h>
19#include <linux/hrtimer.h>
20#include <linux/timerqueue.h>
21#include <linux/rtc.h>
22#include <linux/sched/signal.h>
23#include <linux/sched/debug.h>
24#include <linux/alarmtimer.h>
25#include <linux/mutex.h>
26#include <linux/platform_device.h>
27#include <linux/posix-timers.h>
28#include <linux/workqueue.h>
29#include <linux/freezer.h>
30#include <linux/compat.h>
31#include <linux/module.h>
32
33#include "posix-timers.h"
34
35#define CREATE_TRACE_POINTS
36#include <trace/events/alarmtimer.h>
37
38/**
39 * struct alarm_base - Alarm timer bases
40 * @lock: Lock for syncrhonized access to the base
41 * @timerqueue: Timerqueue head managing the list of events
42 * @gettime: Function to read the time correlating to the base
43 * @base_clockid: clockid for the base
44 */
45static struct alarm_base {
46 spinlock_t lock;
47 struct timerqueue_head timerqueue;
48 ktime_t (*gettime)(void);
49 clockid_t base_clockid;
50} alarm_bases[ALARM_NUMTYPE];
51
52#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
53/* freezer information to handle clock_nanosleep triggered wakeups */
54static enum alarmtimer_type freezer_alarmtype;
55static ktime_t freezer_expires;
56static ktime_t freezer_delta;
57static DEFINE_SPINLOCK(freezer_delta_lock);
58#endif
59
60#ifdef CONFIG_RTC_CLASS
61static struct wakeup_source *ws;
62
63/* rtc timer and device for setting alarm wakeups at suspend */
64static struct rtc_timer rtctimer;
65static struct rtc_device *rtcdev;
66static DEFINE_SPINLOCK(rtcdev_lock);
67
68/**
69 * alarmtimer_get_rtcdev - Return selected rtcdevice
70 *
71 * This function returns the rtc device to use for wakealarms.
72 * If one has not already been chosen, it checks to see if a
73 * functional rtc device is available.
74 */
75struct rtc_device *alarmtimer_get_rtcdev(void)
76{
77 unsigned long flags;
78 struct rtc_device *ret;
79
80 spin_lock_irqsave(&rtcdev_lock, flags);
81 ret = rtcdev;
82 spin_unlock_irqrestore(&rtcdev_lock, flags);
83
84 return ret;
85}
86EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
87
88static int alarmtimer_rtc_add_device(struct device *dev,
89 struct class_interface *class_intf)
90{
91 unsigned long flags;
92 struct rtc_device *rtc = to_rtc_device(dev);
93 struct wakeup_source *__ws;
94
95 if (rtcdev)
96 return -EBUSY;
97
98 if (!rtc->ops->set_alarm)
99 return -1;
100 if (!device_may_wakeup(rtc->dev.parent))
101 return -1;
102
103 __ws = wakeup_source_register("alarmtimer");
104
105 spin_lock_irqsave(&rtcdev_lock, flags);
106 if (!rtcdev) {
107 if (!try_module_get(rtc->owner)) {
108 spin_unlock_irqrestore(&rtcdev_lock, flags);
109 return -1;
110 }
111
112 rtcdev = rtc;
113 /* hold a reference so it doesn't go away */
114 get_device(dev);
115 ws = __ws;
116 __ws = NULL;
117 }
118 spin_unlock_irqrestore(&rtcdev_lock, flags);
119
120 wakeup_source_unregister(__ws);
121
122 return 0;
123}
124
125static inline void alarmtimer_rtc_timer_init(void)
126{
127 rtc_timer_init(&rtctimer, NULL, NULL);
128}
129
130static struct class_interface alarmtimer_rtc_interface = {
131 .add_dev = &alarmtimer_rtc_add_device,
132};
133
134static int alarmtimer_rtc_interface_setup(void)
135{
136 alarmtimer_rtc_interface.class = rtc_class;
137 return class_interface_register(&alarmtimer_rtc_interface);
138}
139static void alarmtimer_rtc_interface_remove(void)
140{
141 class_interface_unregister(&alarmtimer_rtc_interface);
142}
143#else
144struct rtc_device *alarmtimer_get_rtcdev(void)
145{
146 return NULL;
147}
148#define rtcdev (NULL)
149static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
150static inline void alarmtimer_rtc_interface_remove(void) { }
151static inline void alarmtimer_rtc_timer_init(void) { }
152#endif
153
154/**
155 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
156 * @base: pointer to the base where the timer is being run
157 * @alarm: pointer to alarm being enqueued.
158 *
159 * Adds alarm to a alarm_base timerqueue
160 *
161 * Must hold base->lock when calling.
162 */
163static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
164{
165 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
166 timerqueue_del(&base->timerqueue, &alarm->node);
167
168 timerqueue_add(&base->timerqueue, &alarm->node);
169 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
170}
171
172/**
173 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
174 * @base: pointer to the base where the timer is running
175 * @alarm: pointer to alarm being removed
176 *
177 * Removes alarm to a alarm_base timerqueue
178 *
179 * Must hold base->lock when calling.
180 */
181static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
182{
183 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
184 return;
185
186 timerqueue_del(&base->timerqueue, &alarm->node);
187 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
188}
189
190
191/**
192 * alarmtimer_fired - Handles alarm hrtimer being fired.
193 * @timer: pointer to hrtimer being run
194 *
195 * When a alarm timer fires, this runs through the timerqueue to
196 * see which alarms expired, and runs those. If there are more alarm
197 * timers queued for the future, we set the hrtimer to fire when
198 * when the next future alarm timer expires.
199 */
200static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
201{
202 struct alarm *alarm = container_of(timer, struct alarm, timer);
203 struct alarm_base *base = &alarm_bases[alarm->type];
204 unsigned long flags;
205 int ret = HRTIMER_NORESTART;
206 int restart = ALARMTIMER_NORESTART;
207
208 spin_lock_irqsave(&base->lock, flags);
209 alarmtimer_dequeue(base, alarm);
210 spin_unlock_irqrestore(&base->lock, flags);
211
212 if (alarm->function)
213 restart = alarm->function(alarm, base->gettime());
214
215 spin_lock_irqsave(&base->lock, flags);
216 if (restart != ALARMTIMER_NORESTART) {
217 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
218 alarmtimer_enqueue(base, alarm);
219 ret = HRTIMER_RESTART;
220 }
221 spin_unlock_irqrestore(&base->lock, flags);
222
223 trace_alarmtimer_fired(alarm, base->gettime());
224 return ret;
225
226}
227
228ktime_t alarm_expires_remaining(const struct alarm *alarm)
229{
230 struct alarm_base *base = &alarm_bases[alarm->type];
231 return ktime_sub(alarm->node.expires, base->gettime());
232}
233EXPORT_SYMBOL_GPL(alarm_expires_remaining);
234
235#ifdef CONFIG_RTC_CLASS
236/**
237 * alarmtimer_suspend - Suspend time callback
238 * @dev: unused
239 * @state: unused
240 *
241 * When we are going into suspend, we look through the bases
242 * to see which is the soonest timer to expire. We then
243 * set an rtc timer to fire that far into the future, which
244 * will wake us from suspend.
245 */
246static int alarmtimer_suspend(struct device *dev)
247{
248 ktime_t min, now, expires;
249 int i, ret, type;
250 struct rtc_device *rtc;
251 unsigned long flags;
252 struct rtc_time tm;
253
254 spin_lock_irqsave(&freezer_delta_lock, flags);
255 min = freezer_delta;
256 expires = freezer_expires;
257 type = freezer_alarmtype;
258 freezer_delta = 0;
259 spin_unlock_irqrestore(&freezer_delta_lock, flags);
260
261 rtc = alarmtimer_get_rtcdev();
262 /* If we have no rtcdev, just return */
263 if (!rtc)
264 return 0;
265
266 /* Find the soonest timer to expire*/
267 for (i = 0; i < ALARM_NUMTYPE; i++) {
268 struct alarm_base *base = &alarm_bases[i];
269 struct timerqueue_node *next;
270 ktime_t delta;
271
272 spin_lock_irqsave(&base->lock, flags);
273 next = timerqueue_getnext(&base->timerqueue);
274 spin_unlock_irqrestore(&base->lock, flags);
275 if (!next)
276 continue;
277 delta = ktime_sub(next->expires, base->gettime());
278 if (!min || (delta < min)) {
279 expires = next->expires;
280 min = delta;
281 type = i;
282 }
283 }
284 if (min == 0)
285 return 0;
286
287 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
288 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
289 return -EBUSY;
290 }
291
292 trace_alarmtimer_suspend(expires, type);
293
294 /* Setup an rtc timer to fire that far in the future */
295 rtc_timer_cancel(rtc, &rtctimer);
296 rtc_read_time(rtc, &tm);
297 now = rtc_tm_to_ktime(tm);
298 now = ktime_add(now, min);
299
300 /* Set alarm, if in the past reject suspend briefly to handle */
301 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
302 if (ret < 0)
303 __pm_wakeup_event(ws, MSEC_PER_SEC);
304 return ret;
305}
306
307static int alarmtimer_resume(struct device *dev)
308{
309 struct rtc_device *rtc;
310
311 rtc = alarmtimer_get_rtcdev();
312 if (rtc)
313 rtc_timer_cancel(rtc, &rtctimer);
314 return 0;
315}
316
317#else
318static int alarmtimer_suspend(struct device *dev)
319{
320 return 0;
321}
322
323static int alarmtimer_resume(struct device *dev)
324{
325 return 0;
326}
327#endif
328
329static void
330__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
331 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
332{
333 timerqueue_init(&alarm->node);
334 alarm->timer.function = alarmtimer_fired;
335 alarm->function = function;
336 alarm->type = type;
337 alarm->state = ALARMTIMER_STATE_INACTIVE;
338}
339
340/**
341 * alarm_init - Initialize an alarm structure
342 * @alarm: ptr to alarm to be initialized
343 * @type: the type of the alarm
344 * @function: callback that is run when the alarm fires
345 */
346void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
347 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
348{
349 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
350 HRTIMER_MODE_ABS);
351 __alarm_init(alarm, type, function);
352}
353EXPORT_SYMBOL_GPL(alarm_init);
354
355/**
356 * alarm_start - Sets an absolute alarm to fire
357 * @alarm: ptr to alarm to set
358 * @start: time to run the alarm
359 */
360void alarm_start(struct alarm *alarm, ktime_t start)
361{
362 struct alarm_base *base = &alarm_bases[alarm->type];
363 unsigned long flags;
364
365 spin_lock_irqsave(&base->lock, flags);
366 alarm->node.expires = start;
367 alarmtimer_enqueue(base, alarm);
368 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
369 spin_unlock_irqrestore(&base->lock, flags);
370
371 trace_alarmtimer_start(alarm, base->gettime());
372}
373EXPORT_SYMBOL_GPL(alarm_start);
374
375/**
376 * alarm_start_relative - Sets a relative alarm to fire
377 * @alarm: ptr to alarm to set
378 * @start: time relative to now to run the alarm
379 */
380void alarm_start_relative(struct alarm *alarm, ktime_t start)
381{
382 struct alarm_base *base = &alarm_bases[alarm->type];
383
384 start = ktime_add_safe(start, base->gettime());
385 alarm_start(alarm, start);
386}
387EXPORT_SYMBOL_GPL(alarm_start_relative);
388
389void alarm_restart(struct alarm *alarm)
390{
391 struct alarm_base *base = &alarm_bases[alarm->type];
392 unsigned long flags;
393
394 spin_lock_irqsave(&base->lock, flags);
395 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
396 hrtimer_restart(&alarm->timer);
397 alarmtimer_enqueue(base, alarm);
398 spin_unlock_irqrestore(&base->lock, flags);
399}
400EXPORT_SYMBOL_GPL(alarm_restart);
401
402/**
403 * alarm_try_to_cancel - Tries to cancel an alarm timer
404 * @alarm: ptr to alarm to be canceled
405 *
406 * Returns 1 if the timer was canceled, 0 if it was not running,
407 * and -1 if the callback was running
408 */
409int alarm_try_to_cancel(struct alarm *alarm)
410{
411 struct alarm_base *base = &alarm_bases[alarm->type];
412 unsigned long flags;
413 int ret;
414
415 spin_lock_irqsave(&base->lock, flags);
416 ret = hrtimer_try_to_cancel(&alarm->timer);
417 if (ret >= 0)
418 alarmtimer_dequeue(base, alarm);
419 spin_unlock_irqrestore(&base->lock, flags);
420
421 trace_alarmtimer_cancel(alarm, base->gettime());
422 return ret;
423}
424EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
425
426
427/**
428 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
429 * @alarm: ptr to alarm to be canceled
430 *
431 * Returns 1 if the timer was canceled, 0 if it was not active.
432 */
433int alarm_cancel(struct alarm *alarm)
434{
435 for (;;) {
436 int ret = alarm_try_to_cancel(alarm);
437 if (ret >= 0)
438 return ret;
439 cpu_relax();
440 }
441}
442EXPORT_SYMBOL_GPL(alarm_cancel);
443
444
445u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
446{
447 u64 overrun = 1;
448 ktime_t delta;
449
450 delta = ktime_sub(now, alarm->node.expires);
451
452 if (delta < 0)
453 return 0;
454
455 if (unlikely(delta >= interval)) {
456 s64 incr = ktime_to_ns(interval);
457
458 overrun = ktime_divns(delta, incr);
459
460 alarm->node.expires = ktime_add_ns(alarm->node.expires,
461 incr*overrun);
462
463 if (alarm->node.expires > now)
464 return overrun;
465 /*
466 * This (and the ktime_add() below) is the
467 * correction for exact:
468 */
469 overrun++;
470 }
471
472 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
473 return overrun;
474}
475EXPORT_SYMBOL_GPL(alarm_forward);
476
477u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
478{
479 struct alarm_base *base = &alarm_bases[alarm->type];
480
481 return alarm_forward(alarm, base->gettime(), interval);
482}
483EXPORT_SYMBOL_GPL(alarm_forward_now);
484
485#ifdef CONFIG_POSIX_TIMERS
486
487static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
488{
489 struct alarm_base *base;
490 unsigned long flags;
491 ktime_t delta;
492
493 switch(type) {
494 case ALARM_REALTIME:
495 base = &alarm_bases[ALARM_REALTIME];
496 type = ALARM_REALTIME_FREEZER;
497 break;
498 case ALARM_BOOTTIME:
499 base = &alarm_bases[ALARM_BOOTTIME];
500 type = ALARM_BOOTTIME_FREEZER;
501 break;
502 default:
503 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
504 return;
505 }
506
507 delta = ktime_sub(absexp, base->gettime());
508
509 spin_lock_irqsave(&freezer_delta_lock, flags);
510 if (!freezer_delta || (delta < freezer_delta)) {
511 freezer_delta = delta;
512 freezer_expires = absexp;
513 freezer_alarmtype = type;
514 }
515 spin_unlock_irqrestore(&freezer_delta_lock, flags);
516}
517
518/**
519 * clock2alarm - helper that converts from clockid to alarmtypes
520 * @clockid: clockid.
521 */
522static enum alarmtimer_type clock2alarm(clockid_t clockid)
523{
524 if (clockid == CLOCK_REALTIME_ALARM)
525 return ALARM_REALTIME;
526 if (clockid == CLOCK_BOOTTIME_ALARM)
527 return ALARM_BOOTTIME;
528 return -1;
529}
530
531/**
532 * alarm_handle_timer - Callback for posix timers
533 * @alarm: alarm that fired
534 *
535 * Posix timer callback for expired alarm timers.
536 */
537static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
538 ktime_t now)
539{
540 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
541 it.alarm.alarmtimer);
542 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
543 unsigned long flags;
544 int si_private = 0;
545
546 spin_lock_irqsave(&ptr->it_lock, flags);
547
548 ptr->it_active = 0;
549 if (ptr->it_interval)
550 si_private = ++ptr->it_requeue_pending;
551
552 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
553 /*
554 * Handle ignored signals and rearm the timer. This will go
555 * away once we handle ignored signals proper.
556 */
557 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
558 ++ptr->it_requeue_pending;
559 ptr->it_active = 1;
560 result = ALARMTIMER_RESTART;
561 }
562 spin_unlock_irqrestore(&ptr->it_lock, flags);
563
564 return result;
565}
566
567/**
568 * alarm_timer_rearm - Posix timer callback for rearming timer
569 * @timr: Pointer to the posixtimer data struct
570 */
571static void alarm_timer_rearm(struct k_itimer *timr)
572{
573 struct alarm *alarm = &timr->it.alarm.alarmtimer;
574
575 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
576 alarm_start(alarm, alarm->node.expires);
577}
578
579/**
580 * alarm_timer_forward - Posix timer callback for forwarding timer
581 * @timr: Pointer to the posixtimer data struct
582 * @now: Current time to forward the timer against
583 */
584static int alarm_timer_forward(struct k_itimer *timr, ktime_t now)
585{
586 struct alarm *alarm = &timr->it.alarm.alarmtimer;
587
588 return (int) alarm_forward(alarm, timr->it_interval, now);
589}
590
591/**
592 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
593 * @timr: Pointer to the posixtimer data struct
594 * @now: Current time to calculate against
595 */
596static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
597{
598 struct alarm *alarm = &timr->it.alarm.alarmtimer;
599
600 return ktime_sub(now, alarm->node.expires);
601}
602
603/**
604 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
605 * @timr: Pointer to the posixtimer data struct
606 */
607static int alarm_timer_try_to_cancel(struct k_itimer *timr)
608{
609 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
610}
611
612/**
613 * alarm_timer_arm - Posix timer callback to arm a timer
614 * @timr: Pointer to the posixtimer data struct
615 * @expires: The new expiry time
616 * @absolute: Expiry value is absolute time
617 * @sigev_none: Posix timer does not deliver signals
618 */
619static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
620 bool absolute, bool sigev_none)
621{
622 struct alarm *alarm = &timr->it.alarm.alarmtimer;
623 struct alarm_base *base = &alarm_bases[alarm->type];
624
625 if (!absolute)
626 expires = ktime_add_safe(expires, base->gettime());
627 if (sigev_none)
628 alarm->node.expires = expires;
629 else
630 alarm_start(&timr->it.alarm.alarmtimer, expires);
631}
632
633/**
634 * alarm_clock_getres - posix getres interface
635 * @which_clock: clockid
636 * @tp: timespec to fill
637 *
638 * Returns the granularity of underlying alarm base clock
639 */
640static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
641{
642 if (!alarmtimer_get_rtcdev())
643 return -EINVAL;
644
645 tp->tv_sec = 0;
646 tp->tv_nsec = hrtimer_resolution;
647 return 0;
648}
649
650/**
651 * alarm_clock_get - posix clock_get interface
652 * @which_clock: clockid
653 * @tp: timespec to fill.
654 *
655 * Provides the underlying alarm base time.
656 */
657static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
658{
659 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
660
661 if (!alarmtimer_get_rtcdev())
662 return -EINVAL;
663
664 *tp = ktime_to_timespec64(base->gettime());
665 return 0;
666}
667
668/**
669 * alarm_timer_create - posix timer_create interface
670 * @new_timer: k_itimer pointer to manage
671 *
672 * Initializes the k_itimer structure.
673 */
674static int alarm_timer_create(struct k_itimer *new_timer)
675{
676 enum alarmtimer_type type;
677
678 if (!alarmtimer_get_rtcdev())
679 return -ENOTSUPP;
680
681 if (!capable(CAP_WAKE_ALARM))
682 return -EPERM;
683
684 type = clock2alarm(new_timer->it_clock);
685 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
686 return 0;
687}
688
689/**
690 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
691 * @alarm: ptr to alarm that fired
692 *
693 * Wakes up the task that set the alarmtimer
694 */
695static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
696 ktime_t now)
697{
698 struct task_struct *task = (struct task_struct *)alarm->data;
699
700 alarm->data = NULL;
701 if (task)
702 wake_up_process(task);
703 return ALARMTIMER_NORESTART;
704}
705
706/**
707 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
708 * @alarm: ptr to alarmtimer
709 * @absexp: absolute expiration time
710 *
711 * Sets the alarm timer and sleeps until it is fired or interrupted.
712 */
713static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
714 enum alarmtimer_type type)
715{
716 struct restart_block *restart;
717 alarm->data = (void *)current;
718 do {
719 set_current_state(TASK_INTERRUPTIBLE);
720 alarm_start(alarm, absexp);
721 if (likely(alarm->data))
722 schedule();
723
724 alarm_cancel(alarm);
725 } while (alarm->data && !signal_pending(current));
726
727 __set_current_state(TASK_RUNNING);
728
729 destroy_hrtimer_on_stack(&alarm->timer);
730
731 if (!alarm->data)
732 return 0;
733
734 if (freezing(current))
735 alarmtimer_freezerset(absexp, type);
736 restart = ¤t->restart_block;
737 if (restart->nanosleep.type != TT_NONE) {
738 struct timespec64 rmt;
739 ktime_t rem;
740
741 rem = ktime_sub(absexp, alarm_bases[type].gettime());
742
743 if (rem <= 0)
744 return 0;
745 rmt = ktime_to_timespec64(rem);
746
747 return nanosleep_copyout(restart, &rmt);
748 }
749 return -ERESTART_RESTARTBLOCK;
750}
751
752static void
753alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
754 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
755{
756 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
757 HRTIMER_MODE_ABS);
758 __alarm_init(alarm, type, function);
759}
760
761/**
762 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
763 * @restart: ptr to restart block
764 *
765 * Handles restarted clock_nanosleep calls
766 */
767static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
768{
769 enum alarmtimer_type type = restart->nanosleep.clockid;
770 ktime_t exp = restart->nanosleep.expires;
771 struct alarm alarm;
772
773 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
774
775 return alarmtimer_do_nsleep(&alarm, exp, type);
776}
777
778/**
779 * alarm_timer_nsleep - alarmtimer nanosleep
780 * @which_clock: clockid
781 * @flags: determins abstime or relative
782 * @tsreq: requested sleep time (abs or rel)
783 * @rmtp: remaining sleep time saved
784 *
785 * Handles clock_nanosleep calls against _ALARM clockids
786 */
787static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
788 const struct timespec64 *tsreq)
789{
790 enum alarmtimer_type type = clock2alarm(which_clock);
791 struct restart_block *restart = ¤t->restart_block;
792 struct alarm alarm;
793 ktime_t exp;
794 int ret = 0;
795
796 if (!alarmtimer_get_rtcdev())
797 return -ENOTSUPP;
798
799 if (flags & ~TIMER_ABSTIME)
800 return -EINVAL;
801
802 if (!capable(CAP_WAKE_ALARM))
803 return -EPERM;
804
805 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
806
807 exp = timespec64_to_ktime(*tsreq);
808 /* Convert (if necessary) to absolute time */
809 if (flags != TIMER_ABSTIME) {
810 ktime_t now = alarm_bases[type].gettime();
811 exp = ktime_add(now, exp);
812 }
813
814 ret = alarmtimer_do_nsleep(&alarm, exp, type);
815 if (ret != -ERESTART_RESTARTBLOCK)
816 return ret;
817
818 /* abs timers don't set remaining time or restart */
819 if (flags == TIMER_ABSTIME)
820 return -ERESTARTNOHAND;
821
822 restart->fn = alarm_timer_nsleep_restart;
823 restart->nanosleep.clockid = type;
824 restart->nanosleep.expires = exp;
825 return ret;
826}
827
828const struct k_clock alarm_clock = {
829 .clock_getres = alarm_clock_getres,
830 .clock_get = alarm_clock_get,
831 .timer_create = alarm_timer_create,
832 .timer_set = common_timer_set,
833 .timer_del = common_timer_del,
834 .timer_get = common_timer_get,
835 .timer_arm = alarm_timer_arm,
836 .timer_rearm = alarm_timer_rearm,
837 .timer_forward = alarm_timer_forward,
838 .timer_remaining = alarm_timer_remaining,
839 .timer_try_to_cancel = alarm_timer_try_to_cancel,
840 .nsleep = alarm_timer_nsleep,
841};
842#endif /* CONFIG_POSIX_TIMERS */
843
844
845/* Suspend hook structures */
846static const struct dev_pm_ops alarmtimer_pm_ops = {
847 .suspend = alarmtimer_suspend,
848 .resume = alarmtimer_resume,
849};
850
851static struct platform_driver alarmtimer_driver = {
852 .driver = {
853 .name = "alarmtimer",
854 .pm = &alarmtimer_pm_ops,
855 }
856};
857
858/**
859 * alarmtimer_init - Initialize alarm timer code
860 *
861 * This function initializes the alarm bases and registers
862 * the posix clock ids.
863 */
864static int __init alarmtimer_init(void)
865{
866 struct platform_device *pdev;
867 int error = 0;
868 int i;
869
870 alarmtimer_rtc_timer_init();
871
872 /* Initialize alarm bases */
873 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
874 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
875 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
876 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
877 for (i = 0; i < ALARM_NUMTYPE; i++) {
878 timerqueue_init_head(&alarm_bases[i].timerqueue);
879 spin_lock_init(&alarm_bases[i].lock);
880 }
881
882 error = alarmtimer_rtc_interface_setup();
883 if (error)
884 return error;
885
886 error = platform_driver_register(&alarmtimer_driver);
887 if (error)
888 goto out_if;
889
890 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
891 if (IS_ERR(pdev)) {
892 error = PTR_ERR(pdev);
893 goto out_drv;
894 }
895 return 0;
896
897out_drv:
898 platform_driver_unregister(&alarmtimer_driver);
899out_if:
900 alarmtimer_rtc_interface_remove();
901 return error;
902}
903device_initcall(alarmtimer_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Alarmtimer interface
4 *
5 * This interface provides a timer which is similar to hrtimers,
6 * but triggers a RTC alarm if the box is suspend.
7 *
8 * This interface is influenced by the Android RTC Alarm timer
9 * interface.
10 *
11 * Copyright (C) 2010 IBM Corporation
12 *
13 * Author: John Stultz <john.stultz@linaro.org>
14 */
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#include <linux/time_namespace.h>
30
31#include "posix-timers.h"
32
33#define CREATE_TRACE_POINTS
34#include <trace/events/alarmtimer.h>
35
36/**
37 * struct alarm_base - Alarm timer bases
38 * @lock: Lock for syncrhonized access to the base
39 * @timerqueue: Timerqueue head managing the list of events
40 * @get_ktime: Function to read the time correlating to the base
41 * @get_timespec: Function to read the namespace time correlating to the base
42 * @base_clockid: clockid for the base
43 */
44static struct alarm_base {
45 spinlock_t lock;
46 struct timerqueue_head timerqueue;
47 ktime_t (*get_ktime)(void);
48 void (*get_timespec)(struct timespec64 *tp);
49 clockid_t base_clockid;
50} alarm_bases[ALARM_NUMTYPE];
51
52#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
53/* freezer information to handle clock_nanosleep triggered wakeups */
54static enum alarmtimer_type freezer_alarmtype;
55static ktime_t freezer_expires;
56static ktime_t freezer_delta;
57static DEFINE_SPINLOCK(freezer_delta_lock);
58#endif
59
60#ifdef CONFIG_RTC_CLASS
61/* rtc timer and device for setting alarm wakeups at suspend */
62static struct rtc_timer rtctimer;
63static struct rtc_device *rtcdev;
64static DEFINE_SPINLOCK(rtcdev_lock);
65
66/**
67 * alarmtimer_get_rtcdev - Return selected rtcdevice
68 *
69 * This function returns the rtc device to use for wakealarms.
70 */
71struct rtc_device *alarmtimer_get_rtcdev(void)
72{
73 unsigned long flags;
74 struct rtc_device *ret;
75
76 spin_lock_irqsave(&rtcdev_lock, flags);
77 ret = rtcdev;
78 spin_unlock_irqrestore(&rtcdev_lock, flags);
79
80 return ret;
81}
82EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
83
84static int alarmtimer_rtc_add_device(struct device *dev)
85{
86 unsigned long flags;
87 struct rtc_device *rtc = to_rtc_device(dev);
88 struct platform_device *pdev;
89 int ret = 0;
90
91 if (rtcdev)
92 return -EBUSY;
93
94 if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
95 return -1;
96 if (!device_may_wakeup(rtc->dev.parent))
97 return -1;
98
99 pdev = platform_device_register_data(dev, "alarmtimer",
100 PLATFORM_DEVID_AUTO, NULL, 0);
101 if (!IS_ERR(pdev))
102 device_init_wakeup(&pdev->dev, true);
103
104 spin_lock_irqsave(&rtcdev_lock, flags);
105 if (!IS_ERR(pdev) && !rtcdev) {
106 if (!try_module_get(rtc->owner)) {
107 ret = -1;
108 goto unlock;
109 }
110
111 rtcdev = rtc;
112 /* hold a reference so it doesn't go away */
113 get_device(dev);
114 pdev = NULL;
115 } else {
116 ret = -1;
117 }
118unlock:
119 spin_unlock_irqrestore(&rtcdev_lock, flags);
120
121 platform_device_unregister(pdev);
122
123 return ret;
124}
125
126static inline void alarmtimer_rtc_timer_init(void)
127{
128 rtc_timer_init(&rtctimer, NULL, NULL);
129}
130
131static struct class_interface alarmtimer_rtc_interface = {
132 .add_dev = &alarmtimer_rtc_add_device,
133};
134
135static int alarmtimer_rtc_interface_setup(void)
136{
137 alarmtimer_rtc_interface.class = &rtc_class;
138 return class_interface_register(&alarmtimer_rtc_interface);
139}
140static void alarmtimer_rtc_interface_remove(void)
141{
142 class_interface_unregister(&alarmtimer_rtc_interface);
143}
144#else
145static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
146static inline void alarmtimer_rtc_interface_remove(void) { }
147static inline void alarmtimer_rtc_timer_init(void) { }
148#endif
149
150/**
151 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
152 * @base: pointer to the base where the timer is being run
153 * @alarm: pointer to alarm being enqueued.
154 *
155 * Adds alarm to a alarm_base timerqueue
156 *
157 * Must hold base->lock when calling.
158 */
159static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
160{
161 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
162 timerqueue_del(&base->timerqueue, &alarm->node);
163
164 timerqueue_add(&base->timerqueue, &alarm->node);
165 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
166}
167
168/**
169 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
170 * @base: pointer to the base where the timer is running
171 * @alarm: pointer to alarm being removed
172 *
173 * Removes alarm to a alarm_base timerqueue
174 *
175 * Must hold base->lock when calling.
176 */
177static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
178{
179 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
180 return;
181
182 timerqueue_del(&base->timerqueue, &alarm->node);
183 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
184}
185
186
187/**
188 * alarmtimer_fired - Handles alarm hrtimer being fired.
189 * @timer: pointer to hrtimer being run
190 *
191 * When a alarm timer fires, this runs through the timerqueue to
192 * see which alarms expired, and runs those. If there are more alarm
193 * timers queued for the future, we set the hrtimer to fire when
194 * the next future alarm timer expires.
195 */
196static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
197{
198 struct alarm *alarm = container_of(timer, struct alarm, timer);
199 struct alarm_base *base = &alarm_bases[alarm->type];
200
201 scoped_guard (spinlock_irqsave, &base->lock)
202 alarmtimer_dequeue(base, alarm);
203
204 if (alarm->function)
205 alarm->function(alarm, base->get_ktime());
206
207 trace_alarmtimer_fired(alarm, base->get_ktime());
208 return HRTIMER_NORESTART;
209}
210
211ktime_t alarm_expires_remaining(const struct alarm *alarm)
212{
213 struct alarm_base *base = &alarm_bases[alarm->type];
214 return ktime_sub(alarm->node.expires, base->get_ktime());
215}
216EXPORT_SYMBOL_GPL(alarm_expires_remaining);
217
218#ifdef CONFIG_RTC_CLASS
219/**
220 * alarmtimer_suspend - Suspend time callback
221 * @dev: unused
222 *
223 * When we are going into suspend, we look through the bases
224 * to see which is the soonest timer to expire. We then
225 * set an rtc timer to fire that far into the future, which
226 * will wake us from suspend.
227 */
228static int alarmtimer_suspend(struct device *dev)
229{
230 ktime_t min, now, expires;
231 int i, ret, type;
232 struct rtc_device *rtc;
233 unsigned long flags;
234 struct rtc_time tm;
235
236 spin_lock_irqsave(&freezer_delta_lock, flags);
237 min = freezer_delta;
238 expires = freezer_expires;
239 type = freezer_alarmtype;
240 freezer_delta = 0;
241 spin_unlock_irqrestore(&freezer_delta_lock, flags);
242
243 rtc = alarmtimer_get_rtcdev();
244 /* If we have no rtcdev, just return */
245 if (!rtc)
246 return 0;
247
248 /* Find the soonest timer to expire*/
249 for (i = 0; i < ALARM_NUMTYPE; i++) {
250 struct alarm_base *base = &alarm_bases[i];
251 struct timerqueue_node *next;
252 ktime_t delta;
253
254 spin_lock_irqsave(&base->lock, flags);
255 next = timerqueue_getnext(&base->timerqueue);
256 spin_unlock_irqrestore(&base->lock, flags);
257 if (!next)
258 continue;
259 delta = ktime_sub(next->expires, base->get_ktime());
260 if (!min || (delta < min)) {
261 expires = next->expires;
262 min = delta;
263 type = i;
264 }
265 }
266 if (min == 0)
267 return 0;
268
269 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
270 pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
271 return -EBUSY;
272 }
273
274 trace_alarmtimer_suspend(expires, type);
275
276 /* Setup an rtc timer to fire that far in the future */
277 rtc_timer_cancel(rtc, &rtctimer);
278 rtc_read_time(rtc, &tm);
279 now = rtc_tm_to_ktime(tm);
280
281 /*
282 * If the RTC alarm timer only supports a limited time offset, set the
283 * alarm time to the maximum supported value.
284 * The system may wake up earlier (possibly much earlier) than expected
285 * when the alarmtimer runs. This is the best the kernel can do if
286 * the alarmtimer exceeds the time that the rtc device can be programmed
287 * for.
288 */
289 min = rtc_bound_alarmtime(rtc, min);
290
291 now = ktime_add(now, min);
292
293 /* Set alarm, if in the past reject suspend briefly to handle */
294 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
295 if (ret < 0)
296 pm_wakeup_event(dev, MSEC_PER_SEC);
297 return ret;
298}
299
300static int alarmtimer_resume(struct device *dev)
301{
302 struct rtc_device *rtc;
303
304 rtc = alarmtimer_get_rtcdev();
305 if (rtc)
306 rtc_timer_cancel(rtc, &rtctimer);
307 return 0;
308}
309
310#else
311static int alarmtimer_suspend(struct device *dev)
312{
313 return 0;
314}
315
316static int alarmtimer_resume(struct device *dev)
317{
318 return 0;
319}
320#endif
321
322static void
323__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
324 void (*function)(struct alarm *, ktime_t))
325{
326 timerqueue_init(&alarm->node);
327 alarm->function = function;
328 alarm->type = type;
329 alarm->state = ALARMTIMER_STATE_INACTIVE;
330}
331
332/**
333 * alarm_init - Initialize an alarm structure
334 * @alarm: ptr to alarm to be initialized
335 * @type: the type of the alarm
336 * @function: callback that is run when the alarm fires
337 */
338void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
339 void (*function)(struct alarm *, ktime_t))
340{
341 hrtimer_setup(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid,
342 HRTIMER_MODE_ABS);
343 __alarm_init(alarm, type, function);
344}
345EXPORT_SYMBOL_GPL(alarm_init);
346
347/**
348 * alarm_start - Sets an absolute alarm to fire
349 * @alarm: ptr to alarm to set
350 * @start: time to run the alarm
351 */
352void alarm_start(struct alarm *alarm, ktime_t start)
353{
354 struct alarm_base *base = &alarm_bases[alarm->type];
355 unsigned long flags;
356
357 spin_lock_irqsave(&base->lock, flags);
358 alarm->node.expires = start;
359 alarmtimer_enqueue(base, alarm);
360 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
361 spin_unlock_irqrestore(&base->lock, flags);
362
363 trace_alarmtimer_start(alarm, base->get_ktime());
364}
365EXPORT_SYMBOL_GPL(alarm_start);
366
367/**
368 * alarm_start_relative - Sets a relative alarm to fire
369 * @alarm: ptr to alarm to set
370 * @start: time relative to now to run the alarm
371 */
372void alarm_start_relative(struct alarm *alarm, ktime_t start)
373{
374 struct alarm_base *base = &alarm_bases[alarm->type];
375
376 start = ktime_add_safe(start, base->get_ktime());
377 alarm_start(alarm, start);
378}
379EXPORT_SYMBOL_GPL(alarm_start_relative);
380
381void alarm_restart(struct alarm *alarm)
382{
383 struct alarm_base *base = &alarm_bases[alarm->type];
384 unsigned long flags;
385
386 spin_lock_irqsave(&base->lock, flags);
387 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
388 hrtimer_restart(&alarm->timer);
389 alarmtimer_enqueue(base, alarm);
390 spin_unlock_irqrestore(&base->lock, flags);
391}
392EXPORT_SYMBOL_GPL(alarm_restart);
393
394/**
395 * alarm_try_to_cancel - Tries to cancel an alarm timer
396 * @alarm: ptr to alarm to be canceled
397 *
398 * Returns 1 if the timer was canceled, 0 if it was not running,
399 * and -1 if the callback was running
400 */
401int alarm_try_to_cancel(struct alarm *alarm)
402{
403 struct alarm_base *base = &alarm_bases[alarm->type];
404 unsigned long flags;
405 int ret;
406
407 spin_lock_irqsave(&base->lock, flags);
408 ret = hrtimer_try_to_cancel(&alarm->timer);
409 if (ret >= 0)
410 alarmtimer_dequeue(base, alarm);
411 spin_unlock_irqrestore(&base->lock, flags);
412
413 trace_alarmtimer_cancel(alarm, base->get_ktime());
414 return ret;
415}
416EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
417
418
419/**
420 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
421 * @alarm: ptr to alarm to be canceled
422 *
423 * Returns 1 if the timer was canceled, 0 if it was not active.
424 */
425int alarm_cancel(struct alarm *alarm)
426{
427 for (;;) {
428 int ret = alarm_try_to_cancel(alarm);
429 if (ret >= 0)
430 return ret;
431 hrtimer_cancel_wait_running(&alarm->timer);
432 }
433}
434EXPORT_SYMBOL_GPL(alarm_cancel);
435
436
437u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
438{
439 u64 overrun = 1;
440 ktime_t delta;
441
442 delta = ktime_sub(now, alarm->node.expires);
443
444 if (delta < 0)
445 return 0;
446
447 if (unlikely(delta >= interval)) {
448 s64 incr = ktime_to_ns(interval);
449
450 overrun = ktime_divns(delta, incr);
451
452 alarm->node.expires = ktime_add_ns(alarm->node.expires,
453 incr*overrun);
454
455 if (alarm->node.expires > now)
456 return overrun;
457 /*
458 * This (and the ktime_add() below) is the
459 * correction for exact:
460 */
461 overrun++;
462 }
463
464 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
465 return overrun;
466}
467EXPORT_SYMBOL_GPL(alarm_forward);
468
469u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
470{
471 struct alarm_base *base = &alarm_bases[alarm->type];
472
473 return alarm_forward(alarm, base->get_ktime(), interval);
474}
475EXPORT_SYMBOL_GPL(alarm_forward_now);
476
477#ifdef CONFIG_POSIX_TIMERS
478
479static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
480{
481 struct alarm_base *base;
482 unsigned long flags;
483 ktime_t delta;
484
485 switch(type) {
486 case ALARM_REALTIME:
487 base = &alarm_bases[ALARM_REALTIME];
488 type = ALARM_REALTIME_FREEZER;
489 break;
490 case ALARM_BOOTTIME:
491 base = &alarm_bases[ALARM_BOOTTIME];
492 type = ALARM_BOOTTIME_FREEZER;
493 break;
494 default:
495 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
496 return;
497 }
498
499 delta = ktime_sub(absexp, base->get_ktime());
500
501 spin_lock_irqsave(&freezer_delta_lock, flags);
502 if (!freezer_delta || (delta < freezer_delta)) {
503 freezer_delta = delta;
504 freezer_expires = absexp;
505 freezer_alarmtype = type;
506 }
507 spin_unlock_irqrestore(&freezer_delta_lock, flags);
508}
509
510/**
511 * clock2alarm - helper that converts from clockid to alarmtypes
512 * @clockid: clockid.
513 */
514static enum alarmtimer_type clock2alarm(clockid_t clockid)
515{
516 if (clockid == CLOCK_REALTIME_ALARM)
517 return ALARM_REALTIME;
518 if (clockid == CLOCK_BOOTTIME_ALARM)
519 return ALARM_BOOTTIME;
520 return -1;
521}
522
523/**
524 * alarm_handle_timer - Callback for posix timers
525 * @alarm: alarm that fired
526 * @now: time at the timer expiration
527 *
528 * Posix timer callback for expired alarm timers.
529 *
530 * Return: whether the timer is to be restarted
531 */
532static void alarm_handle_timer(struct alarm *alarm, ktime_t now)
533{
534 struct k_itimer *ptr = container_of(alarm, struct k_itimer, it.alarm.alarmtimer);
535
536 guard(spinlock_irqsave)(&ptr->it_lock);
537 posix_timer_queue_signal(ptr);
538}
539
540/**
541 * alarm_timer_rearm - Posix timer callback for rearming timer
542 * @timr: Pointer to the posixtimer data struct
543 */
544static void alarm_timer_rearm(struct k_itimer *timr)
545{
546 struct alarm *alarm = &timr->it.alarm.alarmtimer;
547
548 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
549 alarm_start(alarm, alarm->node.expires);
550}
551
552/**
553 * alarm_timer_forward - Posix timer callback for forwarding timer
554 * @timr: Pointer to the posixtimer data struct
555 * @now: Current time to forward the timer against
556 */
557static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
558{
559 struct alarm *alarm = &timr->it.alarm.alarmtimer;
560
561 return alarm_forward(alarm, timr->it_interval, now);
562}
563
564/**
565 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
566 * @timr: Pointer to the posixtimer data struct
567 * @now: Current time to calculate against
568 */
569static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
570{
571 struct alarm *alarm = &timr->it.alarm.alarmtimer;
572
573 return ktime_sub(alarm->node.expires, now);
574}
575
576/**
577 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
578 * @timr: Pointer to the posixtimer data struct
579 */
580static int alarm_timer_try_to_cancel(struct k_itimer *timr)
581{
582 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
583}
584
585/**
586 * alarm_timer_wait_running - Posix timer callback to wait for a timer
587 * @timr: Pointer to the posixtimer data struct
588 *
589 * Called from the core code when timer cancel detected that the callback
590 * is running. @timr is unlocked and rcu read lock is held to prevent it
591 * from being freed.
592 */
593static void alarm_timer_wait_running(struct k_itimer *timr)
594{
595 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
596}
597
598/**
599 * alarm_timer_arm - Posix timer callback to arm a timer
600 * @timr: Pointer to the posixtimer data struct
601 * @expires: The new expiry time
602 * @absolute: Expiry value is absolute time
603 * @sigev_none: Posix timer does not deliver signals
604 */
605static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
606 bool absolute, bool sigev_none)
607{
608 struct alarm *alarm = &timr->it.alarm.alarmtimer;
609 struct alarm_base *base = &alarm_bases[alarm->type];
610
611 if (!absolute)
612 expires = ktime_add_safe(expires, base->get_ktime());
613 if (sigev_none)
614 alarm->node.expires = expires;
615 else
616 alarm_start(&timr->it.alarm.alarmtimer, expires);
617}
618
619/**
620 * alarm_clock_getres - posix getres interface
621 * @which_clock: clockid
622 * @tp: timespec to fill
623 *
624 * Returns the granularity of underlying alarm base clock
625 */
626static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
627{
628 if (!alarmtimer_get_rtcdev())
629 return -EINVAL;
630
631 tp->tv_sec = 0;
632 tp->tv_nsec = hrtimer_resolution;
633 return 0;
634}
635
636/**
637 * alarm_clock_get_timespec - posix clock_get_timespec interface
638 * @which_clock: clockid
639 * @tp: timespec to fill.
640 *
641 * Provides the underlying alarm base time in a tasks time namespace.
642 */
643static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
644{
645 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
646
647 if (!alarmtimer_get_rtcdev())
648 return -EINVAL;
649
650 base->get_timespec(tp);
651
652 return 0;
653}
654
655/**
656 * alarm_clock_get_ktime - posix clock_get_ktime interface
657 * @which_clock: clockid
658 *
659 * Provides the underlying alarm base time in the root namespace.
660 */
661static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
662{
663 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
664
665 if (!alarmtimer_get_rtcdev())
666 return -EINVAL;
667
668 return base->get_ktime();
669}
670
671/**
672 * alarm_timer_create - posix timer_create interface
673 * @new_timer: k_itimer pointer to manage
674 *
675 * Initializes the k_itimer structure.
676 */
677static int alarm_timer_create(struct k_itimer *new_timer)
678{
679 enum alarmtimer_type type;
680
681 if (!alarmtimer_get_rtcdev())
682 return -EOPNOTSUPP;
683
684 if (!capable(CAP_WAKE_ALARM))
685 return -EPERM;
686
687 type = clock2alarm(new_timer->it_clock);
688 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
689 return 0;
690}
691
692/**
693 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
694 * @alarm: ptr to alarm that fired
695 * @now: time at the timer expiration
696 *
697 * Wakes up the task that set the alarmtimer
698 */
699static void alarmtimer_nsleep_wakeup(struct alarm *alarm, ktime_t now)
700{
701 struct task_struct *task = alarm->data;
702
703 alarm->data = NULL;
704 if (task)
705 wake_up_process(task);
706}
707
708/**
709 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
710 * @alarm: ptr to alarmtimer
711 * @absexp: absolute expiration time
712 * @type: alarm type (BOOTTIME/REALTIME).
713 *
714 * Sets the alarm timer and sleeps until it is fired or interrupted.
715 */
716static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
717 enum alarmtimer_type type)
718{
719 struct restart_block *restart;
720 alarm->data = (void *)current;
721 do {
722 set_current_state(TASK_INTERRUPTIBLE);
723 alarm_start(alarm, absexp);
724 if (likely(alarm->data))
725 schedule();
726
727 alarm_cancel(alarm);
728 } while (alarm->data && !signal_pending(current));
729
730 __set_current_state(TASK_RUNNING);
731
732 destroy_hrtimer_on_stack(&alarm->timer);
733
734 if (!alarm->data)
735 return 0;
736
737 if (freezing(current))
738 alarmtimer_freezerset(absexp, type);
739 restart = ¤t->restart_block;
740 if (restart->nanosleep.type != TT_NONE) {
741 struct timespec64 rmt;
742 ktime_t rem;
743
744 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
745
746 if (rem <= 0)
747 return 0;
748 rmt = ktime_to_timespec64(rem);
749
750 return nanosleep_copyout(restart, &rmt);
751 }
752 return -ERESTART_RESTARTBLOCK;
753}
754
755static void
756alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
757 void (*function)(struct alarm *, ktime_t))
758{
759 hrtimer_setup_on_stack(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid,
760 HRTIMER_MODE_ABS);
761 __alarm_init(alarm, type, function);
762}
763
764/**
765 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
766 * @restart: ptr to restart block
767 *
768 * Handles restarted clock_nanosleep calls
769 */
770static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
771{
772 enum alarmtimer_type type = restart->nanosleep.clockid;
773 ktime_t exp = restart->nanosleep.expires;
774 struct alarm alarm;
775
776 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
777
778 return alarmtimer_do_nsleep(&alarm, exp, type);
779}
780
781/**
782 * alarm_timer_nsleep - alarmtimer nanosleep
783 * @which_clock: clockid
784 * @flags: determines abstime or relative
785 * @tsreq: requested sleep time (abs or rel)
786 *
787 * Handles clock_nanosleep calls against _ALARM clockids
788 */
789static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
790 const struct timespec64 *tsreq)
791{
792 enum alarmtimer_type type = clock2alarm(which_clock);
793 struct restart_block *restart = ¤t->restart_block;
794 struct alarm alarm;
795 ktime_t exp;
796 int ret;
797
798 if (!alarmtimer_get_rtcdev())
799 return -EOPNOTSUPP;
800
801 if (flags & ~TIMER_ABSTIME)
802 return -EINVAL;
803
804 if (!capable(CAP_WAKE_ALARM))
805 return -EPERM;
806
807 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
808
809 exp = timespec64_to_ktime(*tsreq);
810 /* Convert (if necessary) to absolute time */
811 if (flags != TIMER_ABSTIME) {
812 ktime_t now = alarm_bases[type].get_ktime();
813
814 exp = ktime_add_safe(now, exp);
815 } else {
816 exp = timens_ktime_to_host(which_clock, exp);
817 }
818
819 ret = alarmtimer_do_nsleep(&alarm, exp, type);
820 if (ret != -ERESTART_RESTARTBLOCK)
821 return ret;
822
823 /* abs timers don't set remaining time or restart */
824 if (flags == TIMER_ABSTIME)
825 return -ERESTARTNOHAND;
826
827 restart->nanosleep.clockid = type;
828 restart->nanosleep.expires = exp;
829 set_restart_fn(restart, alarm_timer_nsleep_restart);
830 return ret;
831}
832
833const struct k_clock alarm_clock = {
834 .clock_getres = alarm_clock_getres,
835 .clock_get_ktime = alarm_clock_get_ktime,
836 .clock_get_timespec = alarm_clock_get_timespec,
837 .timer_create = alarm_timer_create,
838 .timer_set = common_timer_set,
839 .timer_del = common_timer_del,
840 .timer_get = common_timer_get,
841 .timer_arm = alarm_timer_arm,
842 .timer_rearm = alarm_timer_rearm,
843 .timer_forward = alarm_timer_forward,
844 .timer_remaining = alarm_timer_remaining,
845 .timer_try_to_cancel = alarm_timer_try_to_cancel,
846 .timer_wait_running = alarm_timer_wait_running,
847 .nsleep = alarm_timer_nsleep,
848};
849#endif /* CONFIG_POSIX_TIMERS */
850
851
852/* Suspend hook structures */
853static const struct dev_pm_ops alarmtimer_pm_ops = {
854 .suspend = alarmtimer_suspend,
855 .resume = alarmtimer_resume,
856};
857
858static struct platform_driver alarmtimer_driver = {
859 .driver = {
860 .name = "alarmtimer",
861 .pm = &alarmtimer_pm_ops,
862 }
863};
864
865static void get_boottime_timespec(struct timespec64 *tp)
866{
867 ktime_get_boottime_ts64(tp);
868 timens_add_boottime(tp);
869}
870
871/**
872 * alarmtimer_init - Initialize alarm timer code
873 *
874 * This function initializes the alarm bases and registers
875 * the posix clock ids.
876 */
877static int __init alarmtimer_init(void)
878{
879 int error;
880 int i;
881
882 alarmtimer_rtc_timer_init();
883
884 /* Initialize alarm bases */
885 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
886 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
887 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
888 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
889 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
890 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
891 for (i = 0; i < ALARM_NUMTYPE; i++) {
892 timerqueue_init_head(&alarm_bases[i].timerqueue);
893 spin_lock_init(&alarm_bases[i].lock);
894 }
895
896 error = alarmtimer_rtc_interface_setup();
897 if (error)
898 return error;
899
900 error = platform_driver_register(&alarmtimer_driver);
901 if (error)
902 goto out_if;
903
904 return 0;
905out_if:
906 alarmtimer_rtc_interface_remove();
907 return error;
908}
909device_initcall(alarmtimer_init);