Loading...
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/alarmtimer.h>
23#include <linux/mutex.h>
24#include <linux/platform_device.h>
25#include <linux/posix-timers.h>
26#include <linux/workqueue.h>
27#include <linux/freezer.h>
28
29/**
30 * struct alarm_base - Alarm timer bases
31 * @lock: Lock for syncrhonized access to the base
32 * @timerqueue: Timerqueue head managing the list of events
33 * @timer: hrtimer used to schedule events while running
34 * @gettime: Function to read the time correlating to the base
35 * @base_clockid: clockid for the base
36 */
37static struct alarm_base {
38 spinlock_t lock;
39 struct timerqueue_head timerqueue;
40 ktime_t (*gettime)(void);
41 clockid_t base_clockid;
42} alarm_bases[ALARM_NUMTYPE];
43
44/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
45static ktime_t freezer_delta;
46static DEFINE_SPINLOCK(freezer_delta_lock);
47
48static struct wakeup_source *ws;
49
50#ifdef CONFIG_RTC_CLASS
51/* rtc timer and device for setting alarm wakeups at suspend */
52static struct rtc_timer rtctimer;
53static struct rtc_device *rtcdev;
54static DEFINE_SPINLOCK(rtcdev_lock);
55
56/**
57 * alarmtimer_get_rtcdev - Return selected rtcdevice
58 *
59 * This function returns the rtc device to use for wakealarms.
60 * If one has not already been chosen, it checks to see if a
61 * functional rtc device is available.
62 */
63struct rtc_device *alarmtimer_get_rtcdev(void)
64{
65 unsigned long flags;
66 struct rtc_device *ret;
67
68 spin_lock_irqsave(&rtcdev_lock, flags);
69 ret = rtcdev;
70 spin_unlock_irqrestore(&rtcdev_lock, flags);
71
72 return ret;
73}
74
75
76static int alarmtimer_rtc_add_device(struct device *dev,
77 struct class_interface *class_intf)
78{
79 unsigned long flags;
80 struct rtc_device *rtc = to_rtc_device(dev);
81
82 if (rtcdev)
83 return -EBUSY;
84
85 if (!rtc->ops->set_alarm)
86 return -1;
87 if (!device_may_wakeup(rtc->dev.parent))
88 return -1;
89
90 spin_lock_irqsave(&rtcdev_lock, flags);
91 if (!rtcdev) {
92 rtcdev = rtc;
93 /* hold a reference so it doesn't go away */
94 get_device(dev);
95 }
96 spin_unlock_irqrestore(&rtcdev_lock, flags);
97 return 0;
98}
99
100static inline void alarmtimer_rtc_timer_init(void)
101{
102 rtc_timer_init(&rtctimer, NULL, NULL);
103}
104
105static struct class_interface alarmtimer_rtc_interface = {
106 .add_dev = &alarmtimer_rtc_add_device,
107};
108
109static int alarmtimer_rtc_interface_setup(void)
110{
111 alarmtimer_rtc_interface.class = rtc_class;
112 return class_interface_register(&alarmtimer_rtc_interface);
113}
114static void alarmtimer_rtc_interface_remove(void)
115{
116 class_interface_unregister(&alarmtimer_rtc_interface);
117}
118#else
119struct rtc_device *alarmtimer_get_rtcdev(void)
120{
121 return NULL;
122}
123#define rtcdev (NULL)
124static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
125static inline void alarmtimer_rtc_interface_remove(void) { }
126static inline void alarmtimer_rtc_timer_init(void) { }
127#endif
128
129/**
130 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
131 * @base: pointer to the base where the timer is being run
132 * @alarm: pointer to alarm being enqueued.
133 *
134 * Adds alarm to a alarm_base timerqueue
135 *
136 * Must hold base->lock when calling.
137 */
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
141 timerqueue_del(&base->timerqueue, &alarm->node);
142
143 timerqueue_add(&base->timerqueue, &alarm->node);
144 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
145}
146
147/**
148 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
149 * @base: pointer to the base where the timer is running
150 * @alarm: pointer to alarm being removed
151 *
152 * Removes alarm to a alarm_base timerqueue
153 *
154 * Must hold base->lock when calling.
155 */
156static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
157{
158 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
159 return;
160
161 timerqueue_del(&base->timerqueue, &alarm->node);
162 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
163}
164
165
166/**
167 * alarmtimer_fired - Handles alarm hrtimer being fired.
168 * @timer: pointer to hrtimer being run
169 *
170 * When a alarm timer fires, this runs through the timerqueue to
171 * see which alarms expired, and runs those. If there are more alarm
172 * timers queued for the future, we set the hrtimer to fire when
173 * when the next future alarm timer expires.
174 */
175static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
176{
177 struct alarm *alarm = container_of(timer, struct alarm, timer);
178 struct alarm_base *base = &alarm_bases[alarm->type];
179 unsigned long flags;
180 int ret = HRTIMER_NORESTART;
181 int restart = ALARMTIMER_NORESTART;
182
183 spin_lock_irqsave(&base->lock, flags);
184 alarmtimer_dequeue(base, alarm);
185 spin_unlock_irqrestore(&base->lock, flags);
186
187 if (alarm->function)
188 restart = alarm->function(alarm, base->gettime());
189
190 spin_lock_irqsave(&base->lock, flags);
191 if (restart != ALARMTIMER_NORESTART) {
192 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
193 alarmtimer_enqueue(base, alarm);
194 ret = HRTIMER_RESTART;
195 }
196 spin_unlock_irqrestore(&base->lock, flags);
197
198 return ret;
199
200}
201
202ktime_t alarm_expires_remaining(const struct alarm *alarm)
203{
204 struct alarm_base *base = &alarm_bases[alarm->type];
205 return ktime_sub(alarm->node.expires, base->gettime());
206}
207EXPORT_SYMBOL_GPL(alarm_expires_remaining);
208
209#ifdef CONFIG_RTC_CLASS
210/**
211 * alarmtimer_suspend - Suspend time callback
212 * @dev: unused
213 * @state: unused
214 *
215 * When we are going into suspend, we look through the bases
216 * to see which is the soonest timer to expire. We then
217 * set an rtc timer to fire that far into the future, which
218 * will wake us from suspend.
219 */
220static int alarmtimer_suspend(struct device *dev)
221{
222 struct rtc_time tm;
223 ktime_t min, now;
224 unsigned long flags;
225 struct rtc_device *rtc;
226 int i;
227 int ret;
228
229 spin_lock_irqsave(&freezer_delta_lock, flags);
230 min = freezer_delta;
231 freezer_delta = ktime_set(0, 0);
232 spin_unlock_irqrestore(&freezer_delta_lock, flags);
233
234 rtc = alarmtimer_get_rtcdev();
235 /* If we have no rtcdev, just return */
236 if (!rtc)
237 return 0;
238
239 /* Find the soonest timer to expire*/
240 for (i = 0; i < ALARM_NUMTYPE; i++) {
241 struct alarm_base *base = &alarm_bases[i];
242 struct timerqueue_node *next;
243 ktime_t delta;
244
245 spin_lock_irqsave(&base->lock, flags);
246 next = timerqueue_getnext(&base->timerqueue);
247 spin_unlock_irqrestore(&base->lock, flags);
248 if (!next)
249 continue;
250 delta = ktime_sub(next->expires, base->gettime());
251 if (!min.tv64 || (delta.tv64 < min.tv64))
252 min = delta;
253 }
254 if (min.tv64 == 0)
255 return 0;
256
257 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
258 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
259 return -EBUSY;
260 }
261
262 /* Setup an rtc timer to fire that far in the future */
263 rtc_timer_cancel(rtc, &rtctimer);
264 rtc_read_time(rtc, &tm);
265 now = rtc_tm_to_ktime(tm);
266 now = ktime_add(now, min);
267
268 /* Set alarm, if in the past reject suspend briefly to handle */
269 ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
270 if (ret < 0)
271 __pm_wakeup_event(ws, MSEC_PER_SEC);
272 return ret;
273}
274#else
275static int alarmtimer_suspend(struct device *dev)
276{
277 return 0;
278}
279#endif
280
281static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
282{
283 ktime_t delta;
284 unsigned long flags;
285 struct alarm_base *base = &alarm_bases[type];
286
287 delta = ktime_sub(absexp, base->gettime());
288
289 spin_lock_irqsave(&freezer_delta_lock, flags);
290 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
291 freezer_delta = delta;
292 spin_unlock_irqrestore(&freezer_delta_lock, flags);
293}
294
295
296/**
297 * alarm_init - Initialize an alarm structure
298 * @alarm: ptr to alarm to be initialized
299 * @type: the type of the alarm
300 * @function: callback that is run when the alarm fires
301 */
302void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
303 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
304{
305 timerqueue_init(&alarm->node);
306 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
307 HRTIMER_MODE_ABS);
308 alarm->timer.function = alarmtimer_fired;
309 alarm->function = function;
310 alarm->type = type;
311 alarm->state = ALARMTIMER_STATE_INACTIVE;
312}
313EXPORT_SYMBOL_GPL(alarm_init);
314
315/**
316 * alarm_start - Sets an absolute alarm to fire
317 * @alarm: ptr to alarm to set
318 * @start: time to run the alarm
319 */
320int alarm_start(struct alarm *alarm, ktime_t start)
321{
322 struct alarm_base *base = &alarm_bases[alarm->type];
323 unsigned long flags;
324 int ret;
325
326 spin_lock_irqsave(&base->lock, flags);
327 alarm->node.expires = start;
328 alarmtimer_enqueue(base, alarm);
329 ret = hrtimer_start(&alarm->timer, alarm->node.expires,
330 HRTIMER_MODE_ABS);
331 spin_unlock_irqrestore(&base->lock, flags);
332 return ret;
333}
334EXPORT_SYMBOL_GPL(alarm_start);
335
336/**
337 * alarm_start_relative - Sets a relative alarm to fire
338 * @alarm: ptr to alarm to set
339 * @start: time relative to now to run the alarm
340 */
341int alarm_start_relative(struct alarm *alarm, ktime_t start)
342{
343 struct alarm_base *base = &alarm_bases[alarm->type];
344
345 start = ktime_add(start, base->gettime());
346 return alarm_start(alarm, start);
347}
348EXPORT_SYMBOL_GPL(alarm_start_relative);
349
350void alarm_restart(struct alarm *alarm)
351{
352 struct alarm_base *base = &alarm_bases[alarm->type];
353 unsigned long flags;
354
355 spin_lock_irqsave(&base->lock, flags);
356 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
357 hrtimer_restart(&alarm->timer);
358 alarmtimer_enqueue(base, alarm);
359 spin_unlock_irqrestore(&base->lock, flags);
360}
361EXPORT_SYMBOL_GPL(alarm_restart);
362
363/**
364 * alarm_try_to_cancel - Tries to cancel an alarm timer
365 * @alarm: ptr to alarm to be canceled
366 *
367 * Returns 1 if the timer was canceled, 0 if it was not running,
368 * and -1 if the callback was running
369 */
370int alarm_try_to_cancel(struct alarm *alarm)
371{
372 struct alarm_base *base = &alarm_bases[alarm->type];
373 unsigned long flags;
374 int ret;
375
376 spin_lock_irqsave(&base->lock, flags);
377 ret = hrtimer_try_to_cancel(&alarm->timer);
378 if (ret >= 0)
379 alarmtimer_dequeue(base, alarm);
380 spin_unlock_irqrestore(&base->lock, flags);
381 return ret;
382}
383EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
384
385
386/**
387 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
388 * @alarm: ptr to alarm to be canceled
389 *
390 * Returns 1 if the timer was canceled, 0 if it was not active.
391 */
392int alarm_cancel(struct alarm *alarm)
393{
394 for (;;) {
395 int ret = alarm_try_to_cancel(alarm);
396 if (ret >= 0)
397 return ret;
398 cpu_relax();
399 }
400}
401EXPORT_SYMBOL_GPL(alarm_cancel);
402
403
404u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
405{
406 u64 overrun = 1;
407 ktime_t delta;
408
409 delta = ktime_sub(now, alarm->node.expires);
410
411 if (delta.tv64 < 0)
412 return 0;
413
414 if (unlikely(delta.tv64 >= interval.tv64)) {
415 s64 incr = ktime_to_ns(interval);
416
417 overrun = ktime_divns(delta, incr);
418
419 alarm->node.expires = ktime_add_ns(alarm->node.expires,
420 incr*overrun);
421
422 if (alarm->node.expires.tv64 > now.tv64)
423 return overrun;
424 /*
425 * This (and the ktime_add() below) is the
426 * correction for exact:
427 */
428 overrun++;
429 }
430
431 alarm->node.expires = ktime_add(alarm->node.expires, interval);
432 return overrun;
433}
434EXPORT_SYMBOL_GPL(alarm_forward);
435
436u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
437{
438 struct alarm_base *base = &alarm_bases[alarm->type];
439
440 return alarm_forward(alarm, base->gettime(), interval);
441}
442EXPORT_SYMBOL_GPL(alarm_forward_now);
443
444
445/**
446 * clock2alarm - helper that converts from clockid to alarmtypes
447 * @clockid: clockid.
448 */
449static enum alarmtimer_type clock2alarm(clockid_t clockid)
450{
451 if (clockid == CLOCK_REALTIME_ALARM)
452 return ALARM_REALTIME;
453 if (clockid == CLOCK_BOOTTIME_ALARM)
454 return ALARM_BOOTTIME;
455 return -1;
456}
457
458/**
459 * alarm_handle_timer - Callback for posix timers
460 * @alarm: alarm that fired
461 *
462 * Posix timer callback for expired alarm timers.
463 */
464static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
465 ktime_t now)
466{
467 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
468 it.alarm.alarmtimer);
469 if (posix_timer_event(ptr, 0) != 0)
470 ptr->it_overrun++;
471
472 /* Re-add periodic timers */
473 if (ptr->it.alarm.interval.tv64) {
474 ptr->it_overrun += alarm_forward(alarm, now,
475 ptr->it.alarm.interval);
476 return ALARMTIMER_RESTART;
477 }
478 return ALARMTIMER_NORESTART;
479}
480
481/**
482 * alarm_clock_getres - posix getres interface
483 * @which_clock: clockid
484 * @tp: timespec to fill
485 *
486 * Returns the granularity of underlying alarm base clock
487 */
488static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
489{
490 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
491
492 if (!alarmtimer_get_rtcdev())
493 return -EINVAL;
494
495 return hrtimer_get_res(baseid, tp);
496}
497
498/**
499 * alarm_clock_get - posix clock_get interface
500 * @which_clock: clockid
501 * @tp: timespec to fill.
502 *
503 * Provides the underlying alarm base time.
504 */
505static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
506{
507 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
508
509 if (!alarmtimer_get_rtcdev())
510 return -EINVAL;
511
512 *tp = ktime_to_timespec(base->gettime());
513 return 0;
514}
515
516/**
517 * alarm_timer_create - posix timer_create interface
518 * @new_timer: k_itimer pointer to manage
519 *
520 * Initializes the k_itimer structure.
521 */
522static int alarm_timer_create(struct k_itimer *new_timer)
523{
524 enum alarmtimer_type type;
525 struct alarm_base *base;
526
527 if (!alarmtimer_get_rtcdev())
528 return -ENOTSUPP;
529
530 if (!capable(CAP_WAKE_ALARM))
531 return -EPERM;
532
533 type = clock2alarm(new_timer->it_clock);
534 base = &alarm_bases[type];
535 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
536 return 0;
537}
538
539/**
540 * alarm_timer_get - posix timer_get interface
541 * @new_timer: k_itimer pointer
542 * @cur_setting: itimerspec data to fill
543 *
544 * Copies the itimerspec data out from the k_itimer
545 */
546static void alarm_timer_get(struct k_itimer *timr,
547 struct itimerspec *cur_setting)
548{
549 memset(cur_setting, 0, sizeof(struct itimerspec));
550
551 cur_setting->it_interval =
552 ktime_to_timespec(timr->it.alarm.interval);
553 cur_setting->it_value =
554 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
555 return;
556}
557
558/**
559 * alarm_timer_del - posix timer_del interface
560 * @timr: k_itimer pointer to be deleted
561 *
562 * Cancels any programmed alarms for the given timer.
563 */
564static int alarm_timer_del(struct k_itimer *timr)
565{
566 if (!rtcdev)
567 return -ENOTSUPP;
568
569 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
570 return TIMER_RETRY;
571
572 return 0;
573}
574
575/**
576 * alarm_timer_set - posix timer_set interface
577 * @timr: k_itimer pointer to be deleted
578 * @flags: timer flags
579 * @new_setting: itimerspec to be used
580 * @old_setting: itimerspec being replaced
581 *
582 * Sets the timer to new_setting, and starts the timer.
583 */
584static int alarm_timer_set(struct k_itimer *timr, int flags,
585 struct itimerspec *new_setting,
586 struct itimerspec *old_setting)
587{
588 if (!rtcdev)
589 return -ENOTSUPP;
590
591 if (old_setting)
592 alarm_timer_get(timr, old_setting);
593
594 /* If the timer was already set, cancel it */
595 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
596 return TIMER_RETRY;
597
598 /* start the timer */
599 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
600 alarm_start(&timr->it.alarm.alarmtimer,
601 timespec_to_ktime(new_setting->it_value));
602 return 0;
603}
604
605/**
606 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
607 * @alarm: ptr to alarm that fired
608 *
609 * Wakes up the task that set the alarmtimer
610 */
611static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
612 ktime_t now)
613{
614 struct task_struct *task = (struct task_struct *)alarm->data;
615
616 alarm->data = NULL;
617 if (task)
618 wake_up_process(task);
619 return ALARMTIMER_NORESTART;
620}
621
622/**
623 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
624 * @alarm: ptr to alarmtimer
625 * @absexp: absolute expiration time
626 *
627 * Sets the alarm timer and sleeps until it is fired or interrupted.
628 */
629static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
630{
631 alarm->data = (void *)current;
632 do {
633 set_current_state(TASK_INTERRUPTIBLE);
634 alarm_start(alarm, absexp);
635 if (likely(alarm->data))
636 schedule();
637
638 alarm_cancel(alarm);
639 } while (alarm->data && !signal_pending(current));
640
641 __set_current_state(TASK_RUNNING);
642
643 return (alarm->data == NULL);
644}
645
646
647/**
648 * update_rmtp - Update remaining timespec value
649 * @exp: expiration time
650 * @type: timer type
651 * @rmtp: user pointer to remaining timepsec value
652 *
653 * Helper function that fills in rmtp value with time between
654 * now and the exp value
655 */
656static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
657 struct timespec __user *rmtp)
658{
659 struct timespec rmt;
660 ktime_t rem;
661
662 rem = ktime_sub(exp, alarm_bases[type].gettime());
663
664 if (rem.tv64 <= 0)
665 return 0;
666 rmt = ktime_to_timespec(rem);
667
668 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
669 return -EFAULT;
670
671 return 1;
672
673}
674
675/**
676 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
677 * @restart: ptr to restart block
678 *
679 * Handles restarted clock_nanosleep calls
680 */
681static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
682{
683 enum alarmtimer_type type = restart->nanosleep.clockid;
684 ktime_t exp;
685 struct timespec __user *rmtp;
686 struct alarm alarm;
687 int ret = 0;
688
689 exp.tv64 = restart->nanosleep.expires;
690 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
691
692 if (alarmtimer_do_nsleep(&alarm, exp))
693 goto out;
694
695 if (freezing(current))
696 alarmtimer_freezerset(exp, type);
697
698 rmtp = restart->nanosleep.rmtp;
699 if (rmtp) {
700 ret = update_rmtp(exp, type, rmtp);
701 if (ret <= 0)
702 goto out;
703 }
704
705
706 /* The other values in restart are already filled in */
707 ret = -ERESTART_RESTARTBLOCK;
708out:
709 return ret;
710}
711
712/**
713 * alarm_timer_nsleep - alarmtimer nanosleep
714 * @which_clock: clockid
715 * @flags: determins abstime or relative
716 * @tsreq: requested sleep time (abs or rel)
717 * @rmtp: remaining sleep time saved
718 *
719 * Handles clock_nanosleep calls against _ALARM clockids
720 */
721static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
722 struct timespec *tsreq, struct timespec __user *rmtp)
723{
724 enum alarmtimer_type type = clock2alarm(which_clock);
725 struct alarm alarm;
726 ktime_t exp;
727 int ret = 0;
728 struct restart_block *restart;
729
730 if (!alarmtimer_get_rtcdev())
731 return -ENOTSUPP;
732
733 if (!capable(CAP_WAKE_ALARM))
734 return -EPERM;
735
736 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
737
738 exp = timespec_to_ktime(*tsreq);
739 /* Convert (if necessary) to absolute time */
740 if (flags != TIMER_ABSTIME) {
741 ktime_t now = alarm_bases[type].gettime();
742 exp = ktime_add(now, exp);
743 }
744
745 if (alarmtimer_do_nsleep(&alarm, exp))
746 goto out;
747
748 if (freezing(current))
749 alarmtimer_freezerset(exp, type);
750
751 /* abs timers don't set remaining time or restart */
752 if (flags == TIMER_ABSTIME) {
753 ret = -ERESTARTNOHAND;
754 goto out;
755 }
756
757 if (rmtp) {
758 ret = update_rmtp(exp, type, rmtp);
759 if (ret <= 0)
760 goto out;
761 }
762
763 restart = ¤t_thread_info()->restart_block;
764 restart->fn = alarm_timer_nsleep_restart;
765 restart->nanosleep.clockid = type;
766 restart->nanosleep.expires = exp.tv64;
767 restart->nanosleep.rmtp = rmtp;
768 ret = -ERESTART_RESTARTBLOCK;
769
770out:
771 return ret;
772}
773
774
775/* Suspend hook structures */
776static const struct dev_pm_ops alarmtimer_pm_ops = {
777 .suspend = alarmtimer_suspend,
778};
779
780static struct platform_driver alarmtimer_driver = {
781 .driver = {
782 .name = "alarmtimer",
783 .pm = &alarmtimer_pm_ops,
784 }
785};
786
787/**
788 * alarmtimer_init - Initialize alarm timer code
789 *
790 * This function initializes the alarm bases and registers
791 * the posix clock ids.
792 */
793static int __init alarmtimer_init(void)
794{
795 struct platform_device *pdev;
796 int error = 0;
797 int i;
798 struct k_clock alarm_clock = {
799 .clock_getres = alarm_clock_getres,
800 .clock_get = alarm_clock_get,
801 .timer_create = alarm_timer_create,
802 .timer_set = alarm_timer_set,
803 .timer_del = alarm_timer_del,
804 .timer_get = alarm_timer_get,
805 .nsleep = alarm_timer_nsleep,
806 };
807
808 alarmtimer_rtc_timer_init();
809
810 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
811 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
812
813 /* Initialize alarm bases */
814 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
815 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
816 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
817 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
818 for (i = 0; i < ALARM_NUMTYPE; i++) {
819 timerqueue_init_head(&alarm_bases[i].timerqueue);
820 spin_lock_init(&alarm_bases[i].lock);
821 }
822
823 error = alarmtimer_rtc_interface_setup();
824 if (error)
825 return error;
826
827 error = platform_driver_register(&alarmtimer_driver);
828 if (error)
829 goto out_if;
830
831 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
832 if (IS_ERR(pdev)) {
833 error = PTR_ERR(pdev);
834 goto out_drv;
835 }
836 ws = wakeup_source_register("alarmtimer");
837 return 0;
838
839out_drv:
840 platform_driver_unregister(&alarmtimer_driver);
841out_if:
842 alarmtimer_rtc_interface_remove();
843 return error;
844}
845device_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 struct class_interface *class_intf)
86{
87 unsigned long flags;
88 struct rtc_device *rtc = to_rtc_device(dev);
89 struct platform_device *pdev;
90 int ret = 0;
91
92 if (rtcdev)
93 return -EBUSY;
94
95 if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
96 return -1;
97 if (!device_may_wakeup(rtc->dev.parent))
98 return -1;
99
100 pdev = platform_device_register_data(dev, "alarmtimer",
101 PLATFORM_DEVID_AUTO, NULL, 0);
102 if (!IS_ERR(pdev))
103 device_init_wakeup(&pdev->dev, true);
104
105 spin_lock_irqsave(&rtcdev_lock, flags);
106 if (!IS_ERR(pdev) && !rtcdev) {
107 if (!try_module_get(rtc->owner)) {
108 ret = -1;
109 goto unlock;
110 }
111
112 rtcdev = rtc;
113 /* hold a reference so it doesn't go away */
114 get_device(dev);
115 pdev = NULL;
116 } else {
117 ret = -1;
118 }
119unlock:
120 spin_unlock_irqrestore(&rtcdev_lock, flags);
121
122 platform_device_unregister(pdev);
123
124 return ret;
125}
126
127static inline void alarmtimer_rtc_timer_init(void)
128{
129 rtc_timer_init(&rtctimer, NULL, NULL);
130}
131
132static struct class_interface alarmtimer_rtc_interface = {
133 .add_dev = &alarmtimer_rtc_add_device,
134};
135
136static int alarmtimer_rtc_interface_setup(void)
137{
138 alarmtimer_rtc_interface.class = rtc_class;
139 return class_interface_register(&alarmtimer_rtc_interface);
140}
141static void alarmtimer_rtc_interface_remove(void)
142{
143 class_interface_unregister(&alarmtimer_rtc_interface);
144}
145#else
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 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
153 * @base: pointer to the base where the timer is being run
154 * @alarm: pointer to alarm being enqueued.
155 *
156 * Adds alarm to a alarm_base timerqueue
157 *
158 * Must hold base->lock when calling.
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 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
171 * @base: pointer to the base where the timer is running
172 * @alarm: pointer to alarm being removed
173 *
174 * Removes alarm to a alarm_base timerqueue
175 *
176 * Must hold base->lock when calling.
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 * alarmtimer_fired - Handles alarm hrtimer being fired.
190 * @timer: pointer to hrtimer being run
191 *
192 * When a alarm timer fires, this runs through the timerqueue to
193 * see which alarms expired, and runs those. If there are more alarm
194 * timers queued for the future, we set the hrtimer to fire when
195 * the next future alarm timer expires.
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->get_ktime());
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->get_ktime());
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->get_ktime());
229}
230EXPORT_SYMBOL_GPL(alarm_expires_remaining);
231
232#ifdef CONFIG_RTC_CLASS
233/**
234 * alarmtimer_suspend - Suspend time callback
235 * @dev: unused
236 *
237 * When we are going into suspend, we look through the bases
238 * to see which is the soonest timer to expire. We then
239 * set an rtc timer to fire that far into the future, which
240 * will wake us from suspend.
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 /* If we have no rtcdev, just return */
259 if (!rtc)
260 return 0;
261
262 /* Find the soonest timer to expire*/
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->get_ktime());
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(dev, 2 * MSEC_PER_SEC);
285 return -EBUSY;
286 }
287
288 trace_alarmtimer_suspend(expires, type);
289
290 /* Setup an rtc timer to fire that far in the future */
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 /* Set alarm, if in the past reject suspend briefly to handle */
297 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
298 if (ret < 0)
299 pm_wakeup_event(dev, 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 * alarm_init - Initialize an alarm structure
338 * @alarm: ptr to alarm to be initialized
339 * @type: the type of the alarm
340 * @function: callback that is run when the alarm fires
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 * alarm_start - Sets an absolute alarm to fire
353 * @alarm: ptr to alarm to set
354 * @start: time to run the alarm
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->get_ktime());
368}
369EXPORT_SYMBOL_GPL(alarm_start);
370
371/**
372 * alarm_start_relative - Sets a relative alarm to fire
373 * @alarm: ptr to alarm to set
374 * @start: time relative to now to run the alarm
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->get_ktime());
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 * alarm_try_to_cancel - Tries to cancel an alarm timer
400 * @alarm: ptr to alarm to be canceled
401 *
402 * Returns 1 if the timer was canceled, 0 if it was not running,
403 * and -1 if the callback was running
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->get_ktime());
418 return ret;
419}
420EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
421
422
423/**
424 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
425 * @alarm: ptr to alarm to be canceled
426 *
427 * Returns 1 if the timer was canceled, 0 if it was not active.
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 hrtimer_cancel_wait_running(&alarm->timer);
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 * This (and the ktime_add() below) is the
463 * correction for exact:
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
473static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
474{
475 struct alarm_base *base = &alarm_bases[alarm->type];
476 ktime_t now = base->get_ktime();
477
478 if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) {
479 /*
480 * Same issue as with posix_timer_fn(). Timers which are
481 * periodic but the signal is ignored can starve the system
482 * with a very small interval. The real fix which was
483 * promised in the context of posix_timer_fn() never
484 * materialized, but someone should really work on it.
485 *
486 * To prevent DOS fake @now to be 1 jiffie out which keeps
487 * the overrun accounting correct but creates an
488 * inconsistency vs. timer_gettime(2).
489 */
490 ktime_t kj = NSEC_PER_SEC / HZ;
491
492 if (interval < kj)
493 now = ktime_add(now, kj);
494 }
495
496 return alarm_forward(alarm, now, interval);
497}
498
499u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
500{
501 return __alarm_forward_now(alarm, interval, false);
502}
503EXPORT_SYMBOL_GPL(alarm_forward_now);
504
505#ifdef CONFIG_POSIX_TIMERS
506
507static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
508{
509 struct alarm_base *base;
510 unsigned long flags;
511 ktime_t delta;
512
513 switch(type) {
514 case ALARM_REALTIME:
515 base = &alarm_bases[ALARM_REALTIME];
516 type = ALARM_REALTIME_FREEZER;
517 break;
518 case ALARM_BOOTTIME:
519 base = &alarm_bases[ALARM_BOOTTIME];
520 type = ALARM_BOOTTIME_FREEZER;
521 break;
522 default:
523 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
524 return;
525 }
526
527 delta = ktime_sub(absexp, base->get_ktime());
528
529 spin_lock_irqsave(&freezer_delta_lock, flags);
530 if (!freezer_delta || (delta < freezer_delta)) {
531 freezer_delta = delta;
532 freezer_expires = absexp;
533 freezer_alarmtype = type;
534 }
535 spin_unlock_irqrestore(&freezer_delta_lock, flags);
536}
537
538/**
539 * clock2alarm - helper that converts from clockid to alarmtypes
540 * @clockid: clockid.
541 */
542static enum alarmtimer_type clock2alarm(clockid_t clockid)
543{
544 if (clockid == CLOCK_REALTIME_ALARM)
545 return ALARM_REALTIME;
546 if (clockid == CLOCK_BOOTTIME_ALARM)
547 return ALARM_BOOTTIME;
548 return -1;
549}
550
551/**
552 * alarm_handle_timer - Callback for posix timers
553 * @alarm: alarm that fired
554 * @now: time at the timer expiration
555 *
556 * Posix timer callback for expired alarm timers.
557 *
558 * Return: whether the timer is to be restarted
559 */
560static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
561 ktime_t now)
562{
563 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
564 it.alarm.alarmtimer);
565 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
566 unsigned long flags;
567 int si_private = 0;
568
569 spin_lock_irqsave(&ptr->it_lock, flags);
570
571 ptr->it_active = 0;
572 if (ptr->it_interval)
573 si_private = ++ptr->it_requeue_pending;
574
575 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
576 /*
577 * Handle ignored signals and rearm the timer. This will go
578 * away once we handle ignored signals proper. Ensure that
579 * small intervals cannot starve the system.
580 */
581 ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
582 ++ptr->it_requeue_pending;
583 ptr->it_active = 1;
584 result = ALARMTIMER_RESTART;
585 }
586 spin_unlock_irqrestore(&ptr->it_lock, flags);
587
588 return result;
589}
590
591/**
592 * alarm_timer_rearm - Posix timer callback for rearming timer
593 * @timr: Pointer to the posixtimer data struct
594 */
595static void alarm_timer_rearm(struct k_itimer *timr)
596{
597 struct alarm *alarm = &timr->it.alarm.alarmtimer;
598
599 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
600 alarm_start(alarm, alarm->node.expires);
601}
602
603/**
604 * alarm_timer_forward - Posix timer callback for forwarding timer
605 * @timr: Pointer to the posixtimer data struct
606 * @now: Current time to forward the timer against
607 */
608static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
609{
610 struct alarm *alarm = &timr->it.alarm.alarmtimer;
611
612 return alarm_forward(alarm, timr->it_interval, now);
613}
614
615/**
616 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
617 * @timr: Pointer to the posixtimer data struct
618 * @now: Current time to calculate against
619 */
620static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
621{
622 struct alarm *alarm = &timr->it.alarm.alarmtimer;
623
624 return ktime_sub(alarm->node.expires, now);
625}
626
627/**
628 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
629 * @timr: Pointer to the posixtimer data struct
630 */
631static int alarm_timer_try_to_cancel(struct k_itimer *timr)
632{
633 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
634}
635
636/**
637 * alarm_timer_wait_running - Posix timer callback to wait for a timer
638 * @timr: Pointer to the posixtimer data struct
639 *
640 * Called from the core code when timer cancel detected that the callback
641 * is running. @timr is unlocked and rcu read lock is held to prevent it
642 * from being freed.
643 */
644static void alarm_timer_wait_running(struct k_itimer *timr)
645{
646 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
647}
648
649/**
650 * alarm_timer_arm - Posix timer callback to arm a timer
651 * @timr: Pointer to the posixtimer data struct
652 * @expires: The new expiry time
653 * @absolute: Expiry value is absolute time
654 * @sigev_none: Posix timer does not deliver signals
655 */
656static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
657 bool absolute, bool sigev_none)
658{
659 struct alarm *alarm = &timr->it.alarm.alarmtimer;
660 struct alarm_base *base = &alarm_bases[alarm->type];
661
662 if (!absolute)
663 expires = ktime_add_safe(expires, base->get_ktime());
664 if (sigev_none)
665 alarm->node.expires = expires;
666 else
667 alarm_start(&timr->it.alarm.alarmtimer, expires);
668}
669
670/**
671 * alarm_clock_getres - posix getres interface
672 * @which_clock: clockid
673 * @tp: timespec to fill
674 *
675 * Returns the granularity of underlying alarm base clock
676 */
677static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
678{
679 if (!alarmtimer_get_rtcdev())
680 return -EINVAL;
681
682 tp->tv_sec = 0;
683 tp->tv_nsec = hrtimer_resolution;
684 return 0;
685}
686
687/**
688 * alarm_clock_get_timespec - posix clock_get_timespec interface
689 * @which_clock: clockid
690 * @tp: timespec to fill.
691 *
692 * Provides the underlying alarm base time in a tasks time namespace.
693 */
694static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
695{
696 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
697
698 if (!alarmtimer_get_rtcdev())
699 return -EINVAL;
700
701 base->get_timespec(tp);
702
703 return 0;
704}
705
706/**
707 * alarm_clock_get_ktime - posix clock_get_ktime interface
708 * @which_clock: clockid
709 *
710 * Provides the underlying alarm base time in the root namespace.
711 */
712static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
713{
714 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
715
716 if (!alarmtimer_get_rtcdev())
717 return -EINVAL;
718
719 return base->get_ktime();
720}
721
722/**
723 * alarm_timer_create - posix timer_create interface
724 * @new_timer: k_itimer pointer to manage
725 *
726 * Initializes the k_itimer structure.
727 */
728static int alarm_timer_create(struct k_itimer *new_timer)
729{
730 enum alarmtimer_type type;
731
732 if (!alarmtimer_get_rtcdev())
733 return -EOPNOTSUPP;
734
735 if (!capable(CAP_WAKE_ALARM))
736 return -EPERM;
737
738 type = clock2alarm(new_timer->it_clock);
739 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
740 return 0;
741}
742
743/**
744 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
745 * @alarm: ptr to alarm that fired
746 * @now: time at the timer expiration
747 *
748 * Wakes up the task that set the alarmtimer
749 *
750 * Return: ALARMTIMER_NORESTART
751 */
752static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
753 ktime_t now)
754{
755 struct task_struct *task = (struct task_struct *)alarm->data;
756
757 alarm->data = NULL;
758 if (task)
759 wake_up_process(task);
760 return ALARMTIMER_NORESTART;
761}
762
763/**
764 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
765 * @alarm: ptr to alarmtimer
766 * @absexp: absolute expiration time
767 * @type: alarm type (BOOTTIME/REALTIME).
768 *
769 * Sets the alarm timer and sleeps until it is fired or interrupted.
770 */
771static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
772 enum alarmtimer_type type)
773{
774 struct restart_block *restart;
775 alarm->data = (void *)current;
776 do {
777 set_current_state(TASK_INTERRUPTIBLE);
778 alarm_start(alarm, absexp);
779 if (likely(alarm->data))
780 schedule();
781
782 alarm_cancel(alarm);
783 } while (alarm->data && !signal_pending(current));
784
785 __set_current_state(TASK_RUNNING);
786
787 destroy_hrtimer_on_stack(&alarm->timer);
788
789 if (!alarm->data)
790 return 0;
791
792 if (freezing(current))
793 alarmtimer_freezerset(absexp, type);
794 restart = ¤t->restart_block;
795 if (restart->nanosleep.type != TT_NONE) {
796 struct timespec64 rmt;
797 ktime_t rem;
798
799 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
800
801 if (rem <= 0)
802 return 0;
803 rmt = ktime_to_timespec64(rem);
804
805 return nanosleep_copyout(restart, &rmt);
806 }
807 return -ERESTART_RESTARTBLOCK;
808}
809
810static void
811alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
812 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
813{
814 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
815 HRTIMER_MODE_ABS);
816 __alarm_init(alarm, type, function);
817}
818
819/**
820 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
821 * @restart: ptr to restart block
822 *
823 * Handles restarted clock_nanosleep calls
824 */
825static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
826{
827 enum alarmtimer_type type = restart->nanosleep.clockid;
828 ktime_t exp = restart->nanosleep.expires;
829 struct alarm alarm;
830
831 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
832
833 return alarmtimer_do_nsleep(&alarm, exp, type);
834}
835
836/**
837 * alarm_timer_nsleep - alarmtimer nanosleep
838 * @which_clock: clockid
839 * @flags: determines abstime or relative
840 * @tsreq: requested sleep time (abs or rel)
841 *
842 * Handles clock_nanosleep calls against _ALARM clockids
843 */
844static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
845 const struct timespec64 *tsreq)
846{
847 enum alarmtimer_type type = clock2alarm(which_clock);
848 struct restart_block *restart = ¤t->restart_block;
849 struct alarm alarm;
850 ktime_t exp;
851 int ret = 0;
852
853 if (!alarmtimer_get_rtcdev())
854 return -EOPNOTSUPP;
855
856 if (flags & ~TIMER_ABSTIME)
857 return -EINVAL;
858
859 if (!capable(CAP_WAKE_ALARM))
860 return -EPERM;
861
862 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
863
864 exp = timespec64_to_ktime(*tsreq);
865 /* Convert (if necessary) to absolute time */
866 if (flags != TIMER_ABSTIME) {
867 ktime_t now = alarm_bases[type].get_ktime();
868
869 exp = ktime_add_safe(now, exp);
870 } else {
871 exp = timens_ktime_to_host(which_clock, exp);
872 }
873
874 ret = alarmtimer_do_nsleep(&alarm, exp, type);
875 if (ret != -ERESTART_RESTARTBLOCK)
876 return ret;
877
878 /* abs timers don't set remaining time or restart */
879 if (flags == TIMER_ABSTIME)
880 return -ERESTARTNOHAND;
881
882 restart->nanosleep.clockid = type;
883 restart->nanosleep.expires = exp;
884 set_restart_fn(restart, alarm_timer_nsleep_restart);
885 return ret;
886}
887
888const struct k_clock alarm_clock = {
889 .clock_getres = alarm_clock_getres,
890 .clock_get_ktime = alarm_clock_get_ktime,
891 .clock_get_timespec = alarm_clock_get_timespec,
892 .timer_create = alarm_timer_create,
893 .timer_set = common_timer_set,
894 .timer_del = common_timer_del,
895 .timer_get = common_timer_get,
896 .timer_arm = alarm_timer_arm,
897 .timer_rearm = alarm_timer_rearm,
898 .timer_forward = alarm_timer_forward,
899 .timer_remaining = alarm_timer_remaining,
900 .timer_try_to_cancel = alarm_timer_try_to_cancel,
901 .timer_wait_running = alarm_timer_wait_running,
902 .nsleep = alarm_timer_nsleep,
903};
904#endif /* CONFIG_POSIX_TIMERS */
905
906
907/* Suspend hook structures */
908static const struct dev_pm_ops alarmtimer_pm_ops = {
909 .suspend = alarmtimer_suspend,
910 .resume = alarmtimer_resume,
911};
912
913static struct platform_driver alarmtimer_driver = {
914 .driver = {
915 .name = "alarmtimer",
916 .pm = &alarmtimer_pm_ops,
917 }
918};
919
920static void get_boottime_timespec(struct timespec64 *tp)
921{
922 ktime_get_boottime_ts64(tp);
923 timens_add_boottime(tp);
924}
925
926/**
927 * alarmtimer_init - Initialize alarm timer code
928 *
929 * This function initializes the alarm bases and registers
930 * the posix clock ids.
931 */
932static int __init alarmtimer_init(void)
933{
934 int error;
935 int i;
936
937 alarmtimer_rtc_timer_init();
938
939 /* Initialize alarm bases */
940 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
941 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
942 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
943 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
944 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
945 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
946 for (i = 0; i < ALARM_NUMTYPE; i++) {
947 timerqueue_init_head(&alarm_bases[i].timerqueue);
948 spin_lock_init(&alarm_bases[i].lock);
949 }
950
951 error = alarmtimer_rtc_interface_setup();
952 if (error)
953 return error;
954
955 error = platform_driver_register(&alarmtimer_driver);
956 if (error)
957 goto out_if;
958
959 return 0;
960out_if:
961 alarmtimer_rtc_interface_remove();
962 return error;
963}
964device_initcall(alarmtimer_init);