projects/linux·blob v6.4 · refs

963 lines · 24.4 KiB

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 <[email protected]>
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 unsigned long flags;
201 int ret = HRTIMER_NORESTART;
202 int restart = ALARMTIMER_NORESTART;
203
204 spin_lock_irqsave(&base->lock, flags);
205 alarmtimer_dequeue(base, alarm);
206 spin_unlock_irqrestore(&base->lock, flags);
207
208 if (alarm->function)
209 restart = alarm->function(alarm, base->get_ktime());
210
211 spin_lock_irqsave(&base->lock, flags);
212 if (restart != ALARMTIMER_NORESTART) {
213 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
214 alarmtimer_enqueue(base, alarm);
215 ret = HRTIMER_RESTART;
216 }
217 spin_unlock_irqrestore(&base->lock, flags);
218
219 trace_alarmtimer_fired(alarm, base->get_ktime());
220 return ret;
221
222}
223
224ktime_t alarm_expires_remaining(const struct alarm *alarm)
225{
226 struct alarm_base *base = &alarm_bases[alarm->type];
227 return ktime_sub(alarm->node.expires, base->get_ktime());
228}
229EXPORT_SYMBOL_GPL(alarm_expires_remaining);
230
231#ifdef CONFIG_RTC_CLASS
232/**
233 * alarmtimer_suspend - Suspend time callback
234 * @dev: unused
235 *
236 * When we are going into suspend, we look through the bases
237 * to see which is the soonest timer to expire. We then
238 * set an rtc timer to fire that far into the future, which
239 * will wake us from suspend.
240 */
241static int alarmtimer_suspend(struct device *dev)
242{
243 ktime_t min, now, expires;
244 int i, ret, type;
245 struct rtc_device *rtc;
246 unsigned long flags;
247 struct rtc_time tm;
248
249 spin_lock_irqsave(&freezer_delta_lock, flags);
250 min = freezer_delta;
251 expires = freezer_expires;
252 type = freezer_alarmtype;
253 freezer_delta = 0;
254 spin_unlock_irqrestore(&freezer_delta_lock, flags);
255
256 rtc = alarmtimer_get_rtcdev();
257 /* If we have no rtcdev, just return */
258 if (!rtc)
259 return 0;
260
261 /* Find the soonest timer to expire*/
262 for (i = 0; i < ALARM_NUMTYPE; i++) {
263 struct alarm_base *base = &alarm_bases[i];
264 struct timerqueue_node *next;
265 ktime_t delta;
266
267 spin_lock_irqsave(&base->lock, flags);
268 next = timerqueue_getnext(&base->timerqueue);
269 spin_unlock_irqrestore(&base->lock, flags);
270 if (!next)
271 continue;
272 delta = ktime_sub(next->expires, base->get_ktime());
273 if (!min || (delta < min)) {
274 expires = next->expires;
275 min = delta;
276 type = i;
277 }
278 }
279 if (min == 0)
280 return 0;
281
282 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
283 pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
284 return -EBUSY;
285 }
286
287 trace_alarmtimer_suspend(expires, type);
288
289 /* Setup an rtc timer to fire that far in the future */
290 rtc_timer_cancel(rtc, &rtctimer);
291 rtc_read_time(rtc, &tm);
292 now = rtc_tm_to_ktime(tm);
293 now = ktime_add(now, min);
294
295 /* Set alarm, if in the past reject suspend briefly to handle */
296 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
297 if (ret < 0)
298 pm_wakeup_event(dev, MSEC_PER_SEC);
299 return ret;
300}
301
302static int alarmtimer_resume(struct device *dev)
303{
304 struct rtc_device *rtc;
305
306 rtc = alarmtimer_get_rtcdev();
307 if (rtc)
308 rtc_timer_cancel(rtc, &rtctimer);
309 return 0;
310}
311
312#else
313static int alarmtimer_suspend(struct device *dev)
314{
315 return 0;
316}
317
318static int alarmtimer_resume(struct device *dev)
319{
320 return 0;
321}
322#endif
323
324static void
325__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
326 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
327{
328 timerqueue_init(&alarm->node);
329 alarm->timer.function = alarmtimer_fired;
330 alarm->function = function;
331 alarm->type = type;
332 alarm->state = ALARMTIMER_STATE_INACTIVE;
333}
334
335/**
336 * alarm_init - Initialize an alarm structure
337 * @alarm: ptr to alarm to be initialized
338 * @type: the type of the alarm
339 * @function: callback that is run when the alarm fires
340 */
341void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
342 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
343{
344 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
345 HRTIMER_MODE_ABS);
346 __alarm_init(alarm, type, function);
347}
348EXPORT_SYMBOL_GPL(alarm_init);
349
350/**
351 * alarm_start - Sets an absolute alarm to fire
352 * @alarm: ptr to alarm to set
353 * @start: time to run the alarm
354 */
355void alarm_start(struct alarm *alarm, ktime_t start)
356{
357 struct alarm_base *base = &alarm_bases[alarm->type];
358 unsigned long flags;
359
360 spin_lock_irqsave(&base->lock, flags);
361 alarm->node.expires = start;
362 alarmtimer_enqueue(base, alarm);
363 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
364 spin_unlock_irqrestore(&base->lock, flags);
365
366 trace_alarmtimer_start(alarm, base->get_ktime());
367}
368EXPORT_SYMBOL_GPL(alarm_start);
369
370/**
371 * alarm_start_relative - Sets a relative alarm to fire
372 * @alarm: ptr to alarm to set
373 * @start: time relative to now to run the alarm
374 */
375void alarm_start_relative(struct alarm *alarm, ktime_t start)
376{
377 struct alarm_base *base = &alarm_bases[alarm->type];
378
379 start = ktime_add_safe(start, base->get_ktime());
380 alarm_start(alarm, start);
381}
382EXPORT_SYMBOL_GPL(alarm_start_relative);
383
384void alarm_restart(struct alarm *alarm)
385{
386 struct alarm_base *base = &alarm_bases[alarm->type];
387 unsigned long flags;
388
389 spin_lock_irqsave(&base->lock, flags);
390 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
391 hrtimer_restart(&alarm->timer);
392 alarmtimer_enqueue(base, alarm);
393 spin_unlock_irqrestore(&base->lock, flags);
394}
395EXPORT_SYMBOL_GPL(alarm_restart);
396
397/**
398 * alarm_try_to_cancel - Tries to cancel an alarm timer
399 * @alarm: ptr to alarm to be canceled
400 *
401 * Returns 1 if the timer was canceled, 0 if it was not running,
402 * and -1 if the callback was running
403 */
404int alarm_try_to_cancel(struct alarm *alarm)
405{
406 struct alarm_base *base = &alarm_bases[alarm->type];
407 unsigned long flags;
408 int ret;
409
410 spin_lock_irqsave(&base->lock, flags);
411 ret = hrtimer_try_to_cancel(&alarm->timer);
412 if (ret >= 0)
413 alarmtimer_dequeue(base, alarm);
414 spin_unlock_irqrestore(&base->lock, flags);
415
416 trace_alarmtimer_cancel(alarm, base->get_ktime());
417 return ret;
418}
419EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
420
421
422/**
423 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
424 * @alarm: ptr to alarm to be canceled
425 *
426 * Returns 1 if the timer was canceled, 0 if it was not active.
427 */
428int alarm_cancel(struct alarm *alarm)
429{
430 for (;;) {
431 int ret = alarm_try_to_cancel(alarm);
432 if (ret >= 0)
433 return ret;
434 hrtimer_cancel_wait_running(&alarm->timer);
435 }
436}
437EXPORT_SYMBOL_GPL(alarm_cancel);
438
439
440u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
441{
442 u64 overrun = 1;
443 ktime_t delta;
444
445 delta = ktime_sub(now, alarm->node.expires);
446
447 if (delta < 0)
448 return 0;
449
450 if (unlikely(delta >= interval)) {
451 s64 incr = ktime_to_ns(interval);
452
453 overrun = ktime_divns(delta, incr);
454
455 alarm->node.expires = ktime_add_ns(alarm->node.expires,
456 incr*overrun);
457
458 if (alarm->node.expires > now)
459 return overrun;
460 /*
461 * This (and the ktime_add() below) is the
462 * correction for exact:
463 */
464 overrun++;
465 }
466
467 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
468 return overrun;
469}
470EXPORT_SYMBOL_GPL(alarm_forward);
471
472static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
473{
474 struct alarm_base *base = &alarm_bases[alarm->type];
475 ktime_t now = base->get_ktime();
476
477 if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) {
478 /*
479 * Same issue as with posix_timer_fn(). Timers which are
480 * periodic but the signal is ignored can starve the system
481 * with a very small interval. The real fix which was
482 * promised in the context of posix_timer_fn() never
483 * materialized, but someone should really work on it.
484 *
485 * To prevent DOS fake @now to be 1 jiffie out which keeps
486 * the overrun accounting correct but creates an
487 * inconsistency vs. timer_gettime(2).
488 */
489 ktime_t kj = NSEC_PER_SEC / HZ;
490
491 if (interval < kj)
492 now = ktime_add(now, kj);
493 }
494
495 return alarm_forward(alarm, now, interval);
496}
497
498u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
499{
500 return __alarm_forward_now(alarm, interval, false);
501}
502EXPORT_SYMBOL_GPL(alarm_forward_now);
503
504#ifdef CONFIG_POSIX_TIMERS
505
506static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
507{
508 struct alarm_base *base;
509 unsigned long flags;
510 ktime_t delta;
511
512 switch(type) {
513 case ALARM_REALTIME:
514 base = &alarm_bases[ALARM_REALTIME];
515 type = ALARM_REALTIME_FREEZER;
516 break;
517 case ALARM_BOOTTIME:
518 base = &alarm_bases[ALARM_BOOTTIME];
519 type = ALARM_BOOTTIME_FREEZER;
520 break;
521 default:
522 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
523 return;
524 }
525
526 delta = ktime_sub(absexp, base->get_ktime());
527
528 spin_lock_irqsave(&freezer_delta_lock, flags);
529 if (!freezer_delta || (delta < freezer_delta)) {
530 freezer_delta = delta;
531 freezer_expires = absexp;
532 freezer_alarmtype = type;
533 }
534 spin_unlock_irqrestore(&freezer_delta_lock, flags);
535}
536
537/**
538 * clock2alarm - helper that converts from clockid to alarmtypes
539 * @clockid: clockid.
540 */
541static enum alarmtimer_type clock2alarm(clockid_t clockid)
542{
543 if (clockid == CLOCK_REALTIME_ALARM)
544 return ALARM_REALTIME;
545 if (clockid == CLOCK_BOOTTIME_ALARM)
546 return ALARM_BOOTTIME;
547 return -1;
548}
549
550/**
551 * alarm_handle_timer - Callback for posix timers
552 * @alarm: alarm that fired
553 * @now: time at the timer expiration
554 *
555 * Posix timer callback for expired alarm timers.
556 *
557 * Return: whether the timer is to be restarted
558 */
559static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
560 ktime_t now)
561{
562 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
563 it.alarm.alarmtimer);
564 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
565 unsigned long flags;
566 int si_private = 0;
567
568 spin_lock_irqsave(&ptr->it_lock, flags);
569
570 ptr->it_active = 0;
571 if (ptr->it_interval)
572 si_private = ++ptr->it_requeue_pending;
573
574 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
575 /*
576 * Handle ignored signals and rearm the timer. This will go
577 * away once we handle ignored signals proper. Ensure that
578 * small intervals cannot starve the system.
579 */
580 ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
581 ++ptr->it_requeue_pending;
582 ptr->it_active = 1;
583 result = ALARMTIMER_RESTART;
584 }
585 spin_unlock_irqrestore(&ptr->it_lock, flags);
586
587 return result;
588}
589
590/**
591 * alarm_timer_rearm - Posix timer callback for rearming timer
592 * @timr: Pointer to the posixtimer data struct
593 */
594static void alarm_timer_rearm(struct k_itimer *timr)
595{
596 struct alarm *alarm = &timr->it.alarm.alarmtimer;
597
598 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
599 alarm_start(alarm, alarm->node.expires);
600}
601
602/**
603 * alarm_timer_forward - Posix timer callback for forwarding timer
604 * @timr: Pointer to the posixtimer data struct
605 * @now: Current time to forward the timer against
606 */
607static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
608{
609 struct alarm *alarm = &timr->it.alarm.alarmtimer;
610
611 return alarm_forward(alarm, timr->it_interval, now);
612}
613
614/**
615 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
616 * @timr: Pointer to the posixtimer data struct
617 * @now: Current time to calculate against
618 */
619static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
620{
621 struct alarm *alarm = &timr->it.alarm.alarmtimer;
622
623 return ktime_sub(alarm->node.expires, now);
624}
625
626/**
627 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
628 * @timr: Pointer to the posixtimer data struct
629 */
630static int alarm_timer_try_to_cancel(struct k_itimer *timr)
631{
632 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
633}
634
635/**
636 * alarm_timer_wait_running - Posix timer callback to wait for a timer
637 * @timr: Pointer to the posixtimer data struct
638 *
639 * Called from the core code when timer cancel detected that the callback
640 * is running. @timr is unlocked and rcu read lock is held to prevent it
641 * from being freed.
642 */
643static void alarm_timer_wait_running(struct k_itimer *timr)
644{
645 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
646}
647
648/**
649 * alarm_timer_arm - Posix timer callback to arm a timer
650 * @timr: Pointer to the posixtimer data struct
651 * @expires: The new expiry time
652 * @absolute: Expiry value is absolute time
653 * @sigev_none: Posix timer does not deliver signals
654 */
655static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
656 bool absolute, bool sigev_none)
657{
658 struct alarm *alarm = &timr->it.alarm.alarmtimer;
659 struct alarm_base *base = &alarm_bases[alarm->type];
660
661 if (!absolute)
662 expires = ktime_add_safe(expires, base->get_ktime());
663 if (sigev_none)
664 alarm->node.expires = expires;
665 else
666 alarm_start(&timr->it.alarm.alarmtimer, expires);
667}
668
669/**
670 * alarm_clock_getres - posix getres interface
671 * @which_clock: clockid
672 * @tp: timespec to fill
673 *
674 * Returns the granularity of underlying alarm base clock
675 */
676static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
677{
678 if (!alarmtimer_get_rtcdev())
679 return -EINVAL;
680
681 tp->tv_sec = 0;
682 tp->tv_nsec = hrtimer_resolution;
683 return 0;
684}
685
686/**
687 * alarm_clock_get_timespec - posix clock_get_timespec interface
688 * @which_clock: clockid
689 * @tp: timespec to fill.
690 *
691 * Provides the underlying alarm base time in a tasks time namespace.
692 */
693static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
694{
695 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
696
697 if (!alarmtimer_get_rtcdev())
698 return -EINVAL;
699
700 base->get_timespec(tp);
701
702 return 0;
703}
704
705/**
706 * alarm_clock_get_ktime - posix clock_get_ktime interface
707 * @which_clock: clockid
708 *
709 * Provides the underlying alarm base time in the root namespace.
710 */
711static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
712{
713 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
714
715 if (!alarmtimer_get_rtcdev())
716 return -EINVAL;
717
718 return base->get_ktime();
719}
720
721/**
722 * alarm_timer_create - posix timer_create interface
723 * @new_timer: k_itimer pointer to manage
724 *
725 * Initializes the k_itimer structure.
726 */
727static int alarm_timer_create(struct k_itimer *new_timer)
728{
729 enum alarmtimer_type type;
730
731 if (!alarmtimer_get_rtcdev())
732 return -EOPNOTSUPP;
733
734 if (!capable(CAP_WAKE_ALARM))
735 return -EPERM;
736
737 type = clock2alarm(new_timer->it_clock);
738 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
739 return 0;
740}
741
742/**
743 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
744 * @alarm: ptr to alarm that fired
745 * @now: time at the timer expiration
746 *
747 * Wakes up the task that set the alarmtimer
748 *
749 * Return: ALARMTIMER_NORESTART
750 */
751static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
752 ktime_t now)
753{
754 struct task_struct *task = (struct task_struct *)alarm->data;
755
756 alarm->data = NULL;
757 if (task)
758 wake_up_process(task);
759 return ALARMTIMER_NORESTART;
760}
761
762/**
763 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
764 * @alarm: ptr to alarmtimer
765 * @absexp: absolute expiration time
766 * @type: alarm type (BOOTTIME/REALTIME).
767 *
768 * Sets the alarm timer and sleeps until it is fired or interrupted.
769 */
770static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
771 enum alarmtimer_type type)
772{
773 struct restart_block *restart;
774 alarm->data = (void *)current;
775 do {
776 set_current_state(TASK_INTERRUPTIBLE);
777 alarm_start(alarm, absexp);
778 if (likely(alarm->data))
779 schedule();
780
781 alarm_cancel(alarm);
782 } while (alarm->data && !signal_pending(current));
783
784 __set_current_state(TASK_RUNNING);
785
786 destroy_hrtimer_on_stack(&alarm->timer);
787
788 if (!alarm->data)
789 return 0;
790
791 if (freezing(current))
792 alarmtimer_freezerset(absexp, type);
793 restart = &current->restart_block;
794 if (restart->nanosleep.type != TT_NONE) {
795 struct timespec64 rmt;
796 ktime_t rem;
797
798 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
799
800 if (rem <= 0)
801 return 0;
802 rmt = ktime_to_timespec64(rem);
803
804 return nanosleep_copyout(restart, &rmt);
805 }
806 return -ERESTART_RESTARTBLOCK;
807}
808
809static void
810alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
811 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
812{
813 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
814 HRTIMER_MODE_ABS);
815 __alarm_init(alarm, type, function);
816}
817
818/**
819 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
820 * @restart: ptr to restart block
821 *
822 * Handles restarted clock_nanosleep calls
823 */
824static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
825{
826 enum alarmtimer_type type = restart->nanosleep.clockid;
827 ktime_t exp = restart->nanosleep.expires;
828 struct alarm alarm;
829
830 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
831
832 return alarmtimer_do_nsleep(&alarm, exp, type);
833}
834
835/**
836 * alarm_timer_nsleep - alarmtimer nanosleep
837 * @which_clock: clockid
838 * @flags: determines abstime or relative
839 * @tsreq: requested sleep time (abs or rel)
840 *
841 * Handles clock_nanosleep calls against _ALARM clockids
842 */
843static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
844 const struct timespec64 *tsreq)
845{
846 enum alarmtimer_type type = clock2alarm(which_clock);
847 struct restart_block *restart = &current->restart_block;
848 struct alarm alarm;
849 ktime_t exp;
850 int ret = 0;
851
852 if (!alarmtimer_get_rtcdev())
853 return -EOPNOTSUPP;
854
855 if (flags & ~TIMER_ABSTIME)
856 return -EINVAL;
857
858 if (!capable(CAP_WAKE_ALARM))
859 return -EPERM;
860
861 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
862
863 exp = timespec64_to_ktime(*tsreq);
864 /* Convert (if necessary) to absolute time */
865 if (flags != TIMER_ABSTIME) {
866 ktime_t now = alarm_bases[type].get_ktime();
867
868 exp = ktime_add_safe(now, exp);
869 } else {
870 exp = timens_ktime_to_host(which_clock, exp);
871 }
872
873 ret = alarmtimer_do_nsleep(&alarm, exp, type);
874 if (ret != -ERESTART_RESTARTBLOCK)
875 return ret;
876
877 /* abs timers don't set remaining time or restart */
878 if (flags == TIMER_ABSTIME)
879 return -ERESTARTNOHAND;
880
881 restart->nanosleep.clockid = type;
882 restart->nanosleep.expires = exp;
883 set_restart_fn(restart, alarm_timer_nsleep_restart);
884 return ret;
885}
886
887const struct k_clock alarm_clock = {
888 .clock_getres = alarm_clock_getres,
889 .clock_get_ktime = alarm_clock_get_ktime,
890 .clock_get_timespec = alarm_clock_get_timespec,
891 .timer_create = alarm_timer_create,
892 .timer_set = common_timer_set,
893 .timer_del = common_timer_del,
894 .timer_get = common_timer_get,
895 .timer_arm = alarm_timer_arm,
896 .timer_rearm = alarm_timer_rearm,
897 .timer_forward = alarm_timer_forward,
898 .timer_remaining = alarm_timer_remaining,
899 .timer_try_to_cancel = alarm_timer_try_to_cancel,
900 .timer_wait_running = alarm_timer_wait_running,
901 .nsleep = alarm_timer_nsleep,
902};
903#endif /* CONFIG_POSIX_TIMERS */
904
905
906/* Suspend hook structures */
907static const struct dev_pm_ops alarmtimer_pm_ops = {
908 .suspend = alarmtimer_suspend,
909 .resume = alarmtimer_resume,
910};
911
912static struct platform_driver alarmtimer_driver = {
913 .driver = {
914 .name = "alarmtimer",
915 .pm = &alarmtimer_pm_ops,
916 }
917};
918
919static void get_boottime_timespec(struct timespec64 *tp)
920{
921 ktime_get_boottime_ts64(tp);
922 timens_add_boottime(tp);
923}
924
925/**
926 * alarmtimer_init - Initialize alarm timer code
927 *
928 * This function initializes the alarm bases and registers
929 * the posix clock ids.
930 */
931static int __init alarmtimer_init(void)
932{
933 int error;
934 int i;
935
936 alarmtimer_rtc_timer_init();
937
938 /* Initialize alarm bases */
939 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
940 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
941 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
942 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
943 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
944 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
945 for (i = 0; i < ALARM_NUMTYPE; i++) {
946 timerqueue_init_head(&alarm_bases[i].timerqueue);
947 spin_lock_init(&alarm_bases[i].lock);
948 }
949
950 error = alarmtimer_rtc_interface_setup();
951 if (error)
952 return error;
953
954 error = platform_driver_register(&alarmtimer_driver);
955 if (error)
956 goto out_if;
957
958 return 0;
959out_if:
960 alarmtimer_rtc_interface_remove();
961 return error;
962}
963device_initcall(alarmtimer_init);