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 */
44 static 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 */
54 static enum alarmtimer_type freezer_alarmtype;
55 static ktime_t freezer_expires;
56 static ktime_t freezer_delta;
57 static DEFINE_SPINLOCK(freezer_delta_lock);
58 #endif
59
60 #ifdef CONFIG_RTC_CLASS
61 /* rtc timer and device for setting alarm wakeups at suspend */
62 static struct rtc_timer rtctimer;
63 static struct rtc_device *rtcdev;
64 static 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 */
71 struct 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 }
82 EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
83
84 static 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 }
118 unlock:
119 spin_unlock_irqrestore(&rtcdev_lock, flags);
120
121 platform_device_unregister(pdev);
122
123 return ret;
124 }
125
126 static inline void alarmtimer_rtc_timer_init(void)
127 {
128 rtc_timer_init(&rtctimer, NULL, NULL);
129 }
130
131 static struct class_interface alarmtimer_rtc_interface = {
132 .add_dev = &alarmtimer_rtc_add_device,
133 };
134
135 static int alarmtimer_rtc_interface_setup(void)
136 {
137 alarmtimer_rtc_interface.class = &rtc_class;
138 return class_interface_register(&alarmtimer_rtc_interface);
139 }
140 static void alarmtimer_rtc_interface_remove(void)
141 {
142 class_interface_unregister(&alarmtimer_rtc_interface);
143 }
144 #else
145 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
146 static inline void alarmtimer_rtc_interface_remove(void) { }
147 static 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 */
159 static 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 */
177 static 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 */
196 static 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
224 ktime_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 }
229 EXPORT_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 */
241 static 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
294 /*
295 * If the RTC alarm timer only supports a limited time offset, set the
296 * alarm time to the maximum supported value.
297 * The system may wake up earlier (possibly much earlier) than expected
298 * when the alarmtimer runs. This is the best the kernel can do if
299 * the alarmtimer exceeds the time that the rtc device can be programmed
300 * for.
301 */
302 min = rtc_bound_alarmtime(rtc, min);
303
304 now = ktime_add(now, min);
305
306 /* Set alarm, if in the past reject suspend briefly to handle */
307 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
308 if (ret < 0)
309 pm_wakeup_event(dev, MSEC_PER_SEC);
310 return ret;
311 }
312
313 static int alarmtimer_resume(struct device *dev)
314 {
315 struct rtc_device *rtc;
316
317 rtc = alarmtimer_get_rtcdev();
318 if (rtc)
319 rtc_timer_cancel(rtc, &rtctimer);
320 return 0;
321 }
322
323 #else
324 static int alarmtimer_suspend(struct device *dev)
325 {
326 return 0;
327 }
328
329 static int alarmtimer_resume(struct device *dev)
330 {
331 return 0;
332 }
333 #endif
334
335 static void
336 __alarm_init(struct alarm *alarm, enum alarmtimer_type type,
337 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
338 {
339 timerqueue_init(&alarm->node);
340 alarm->timer.function = alarmtimer_fired;
341 alarm->function = function;
342 alarm->type = type;
343 alarm->state = ALARMTIMER_STATE_INACTIVE;
344 }
345
346 /**
347 * alarm_init - Initialize an alarm structure
348 * @alarm: ptr to alarm to be initialized
349 * @type: the type of the alarm
350 * @function: callback that is run when the alarm fires
351 */
352 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
353 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
354 {
355 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
356 HRTIMER_MODE_ABS);
357 __alarm_init(alarm, type, function);
358 }
359 EXPORT_SYMBOL_GPL(alarm_init);
360
361 /**
362 * alarm_start - Sets an absolute alarm to fire
363 * @alarm: ptr to alarm to set
364 * @start: time to run the alarm
365 */
366 void alarm_start(struct alarm *alarm, ktime_t start)
367 {
368 struct alarm_base *base = &alarm_bases[alarm->type];
369 unsigned long flags;
370
371 spin_lock_irqsave(&base->lock, flags);
372 alarm->node.expires = start;
373 alarmtimer_enqueue(base, alarm);
374 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
375 spin_unlock_irqrestore(&base->lock, flags);
376
377 trace_alarmtimer_start(alarm, base->get_ktime());
378 }
379 EXPORT_SYMBOL_GPL(alarm_start);
380
381 /**
382 * alarm_start_relative - Sets a relative alarm to fire
383 * @alarm: ptr to alarm to set
384 * @start: time relative to now to run the alarm
385 */
386 void alarm_start_relative(struct alarm *alarm, ktime_t start)
387 {
388 struct alarm_base *base = &alarm_bases[alarm->type];
389
390 start = ktime_add_safe(start, base->get_ktime());
391 alarm_start(alarm, start);
392 }
393 EXPORT_SYMBOL_GPL(alarm_start_relative);
394
395 void alarm_restart(struct alarm *alarm)
396 {
397 struct alarm_base *base = &alarm_bases[alarm->type];
398 unsigned long flags;
399
400 spin_lock_irqsave(&base->lock, flags);
401 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
402 hrtimer_restart(&alarm->timer);
403 alarmtimer_enqueue(base, alarm);
404 spin_unlock_irqrestore(&base->lock, flags);
405 }
406 EXPORT_SYMBOL_GPL(alarm_restart);
407
408 /**
409 * alarm_try_to_cancel - Tries to cancel an alarm timer
410 * @alarm: ptr to alarm to be canceled
411 *
412 * Returns 1 if the timer was canceled, 0 if it was not running,
413 * and -1 if the callback was running
414 */
415 int alarm_try_to_cancel(struct alarm *alarm)
416 {
417 struct alarm_base *base = &alarm_bases[alarm->type];
418 unsigned long flags;
419 int ret;
420
421 spin_lock_irqsave(&base->lock, flags);
422 ret = hrtimer_try_to_cancel(&alarm->timer);
423 if (ret >= 0)
424 alarmtimer_dequeue(base, alarm);
425 spin_unlock_irqrestore(&base->lock, flags);
426
427 trace_alarmtimer_cancel(alarm, base->get_ktime());
428 return ret;
429 }
430 EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
431
432
433 /**
434 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
435 * @alarm: ptr to alarm to be canceled
436 *
437 * Returns 1 if the timer was canceled, 0 if it was not active.
438 */
439 int alarm_cancel(struct alarm *alarm)
440 {
441 for (;;) {
442 int ret = alarm_try_to_cancel(alarm);
443 if (ret >= 0)
444 return ret;
445 hrtimer_cancel_wait_running(&alarm->timer);
446 }
447 }
448 EXPORT_SYMBOL_GPL(alarm_cancel);
449
450
451 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
452 {
453 u64 overrun = 1;
454 ktime_t delta;
455
456 delta = ktime_sub(now, alarm->node.expires);
457
458 if (delta < 0)
459 return 0;
460
461 if (unlikely(delta >= interval)) {
462 s64 incr = ktime_to_ns(interval);
463
464 overrun = ktime_divns(delta, incr);
465
466 alarm->node.expires = ktime_add_ns(alarm->node.expires,
467 incr*overrun);
468
469 if (alarm->node.expires > now)
470 return overrun;
471 /*
472 * This (and the ktime_add() below) is the
473 * correction for exact:
474 */
475 overrun++;
476 }
477
478 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
479 return overrun;
480 }
481 EXPORT_SYMBOL_GPL(alarm_forward);
482
483 static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
484 {
485 struct alarm_base *base = &alarm_bases[alarm->type];
486 ktime_t now = base->get_ktime();
487
488 if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) {
489 /*
490 * Same issue as with posix_timer_fn(). Timers which are
491 * periodic but the signal is ignored can starve the system
492 * with a very small interval. The real fix which was
493 * promised in the context of posix_timer_fn() never
494 * materialized, but someone should really work on it.
495 *
496 * To prevent DOS fake @now to be 1 jiffie out which keeps
497 * the overrun accounting correct but creates an
498 * inconsistency vs. timer_gettime(2).
499 */
500 ktime_t kj = NSEC_PER_SEC / HZ;
501
502 if (interval < kj)
503 now = ktime_add(now, kj);
504 }
505
506 return alarm_forward(alarm, now, interval);
507 }
508
509 u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
510 {
511 return __alarm_forward_now(alarm, interval, false);
512 }
513 EXPORT_SYMBOL_GPL(alarm_forward_now);
514
515 #ifdef CONFIG_POSIX_TIMERS
516
517 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
518 {
519 struct alarm_base *base;
520 unsigned long flags;
521 ktime_t delta;
522
523 switch(type) {
524 case ALARM_REALTIME:
525 base = &alarm_bases[ALARM_REALTIME];
526 type = ALARM_REALTIME_FREEZER;
527 break;
528 case ALARM_BOOTTIME:
529 base = &alarm_bases[ALARM_BOOTTIME];
530 type = ALARM_BOOTTIME_FREEZER;
531 break;
532 default:
533 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
534 return;
535 }
536
537 delta = ktime_sub(absexp, base->get_ktime());
538
539 spin_lock_irqsave(&freezer_delta_lock, flags);
540 if (!freezer_delta || (delta < freezer_delta)) {
541 freezer_delta = delta;
542 freezer_expires = absexp;
543 freezer_alarmtype = type;
544 }
545 spin_unlock_irqrestore(&freezer_delta_lock, flags);
546 }
547
548 /**
549 * clock2alarm - helper that converts from clockid to alarmtypes
550 * @clockid: clockid.
551 */
552 static enum alarmtimer_type clock2alarm(clockid_t clockid)
553 {
554 if (clockid == CLOCK_REALTIME_ALARM)
555 return ALARM_REALTIME;
556 if (clockid == CLOCK_BOOTTIME_ALARM)
557 return ALARM_BOOTTIME;
558 return -1;
559 }
560
561 /**
562 * alarm_handle_timer - Callback for posix timers
563 * @alarm: alarm that fired
564 * @now: time at the timer expiration
565 *
566 * Posix timer callback for expired alarm timers.
567 *
568 * Return: whether the timer is to be restarted
569 */
570 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
571 ktime_t now)
572 {
573 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
574 it.alarm.alarmtimer);
575 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
576 unsigned long flags;
577 int si_private = 0;
578
579 spin_lock_irqsave(&ptr->it_lock, flags);
580
581 ptr->it_active = 0;
582 if (ptr->it_interval)
583 si_private = ++ptr->it_requeue_pending;
584
585 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
586 /*
587 * Handle ignored signals and rearm the timer. This will go
588 * away once we handle ignored signals proper. Ensure that
589 * small intervals cannot starve the system.
590 */
591 ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
592 ++ptr->it_requeue_pending;
593 ptr->it_active = 1;
594 result = ALARMTIMER_RESTART;
595 }
596 spin_unlock_irqrestore(&ptr->it_lock, flags);
597
598 return result;
599 }
600
601 /**
602 * alarm_timer_rearm - Posix timer callback for rearming timer
603 * @timr: Pointer to the posixtimer data struct
604 */
605 static void alarm_timer_rearm(struct k_itimer *timr)
606 {
607 struct alarm *alarm = &timr->it.alarm.alarmtimer;
608
609 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
610 alarm_start(alarm, alarm->node.expires);
611 }
612
613 /**
614 * alarm_timer_forward - Posix timer callback for forwarding timer
615 * @timr: Pointer to the posixtimer data struct
616 * @now: Current time to forward the timer against
617 */
618 static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
619 {
620 struct alarm *alarm = &timr->it.alarm.alarmtimer;
621
622 return alarm_forward(alarm, timr->it_interval, now);
623 }
624
625 /**
626 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
627 * @timr: Pointer to the posixtimer data struct
628 * @now: Current time to calculate against
629 */
630 static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
631 {
632 struct alarm *alarm = &timr->it.alarm.alarmtimer;
633
634 return ktime_sub(alarm->node.expires, now);
635 }
636
637 /**
638 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
639 * @timr: Pointer to the posixtimer data struct
640 */
641 static int alarm_timer_try_to_cancel(struct k_itimer *timr)
642 {
643 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
644 }
645
646 /**
647 * alarm_timer_wait_running - Posix timer callback to wait for a timer
648 * @timr: Pointer to the posixtimer data struct
649 *
650 * Called from the core code when timer cancel detected that the callback
651 * is running. @timr is unlocked and rcu read lock is held to prevent it
652 * from being freed.
653 */
654 static void alarm_timer_wait_running(struct k_itimer *timr)
655 {
656 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
657 }
658
659 /**
660 * alarm_timer_arm - Posix timer callback to arm a timer
661 * @timr: Pointer to the posixtimer data struct
662 * @expires: The new expiry time
663 * @absolute: Expiry value is absolute time
664 * @sigev_none: Posix timer does not deliver signals
665 */
666 static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
667 bool absolute, bool sigev_none)
668 {
669 struct alarm *alarm = &timr->it.alarm.alarmtimer;
670 struct alarm_base *base = &alarm_bases[alarm->type];
671
672 if (!absolute)
673 expires = ktime_add_safe(expires, base->get_ktime());
674 if (sigev_none)
675 alarm->node.expires = expires;
676 else
677 alarm_start(&timr->it.alarm.alarmtimer, expires);
678 }
679
680 /**
681 * alarm_clock_getres - posix getres interface
682 * @which_clock: clockid
683 * @tp: timespec to fill
684 *
685 * Returns the granularity of underlying alarm base clock
686 */
687 static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
688 {
689 if (!alarmtimer_get_rtcdev())
690 return -EINVAL;
691
692 tp->tv_sec = 0;
693 tp->tv_nsec = hrtimer_resolution;
694 return 0;
695 }
696
697 /**
698 * alarm_clock_get_timespec - posix clock_get_timespec interface
699 * @which_clock: clockid
700 * @tp: timespec to fill.
701 *
702 * Provides the underlying alarm base time in a tasks time namespace.
703 */
704 static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
705 {
706 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
707
708 if (!alarmtimer_get_rtcdev())
709 return -EINVAL;
710
711 base->get_timespec(tp);
712
713 return 0;
714 }
715
716 /**
717 * alarm_clock_get_ktime - posix clock_get_ktime interface
718 * @which_clock: clockid
719 *
720 * Provides the underlying alarm base time in the root namespace.
721 */
722 static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
723 {
724 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
725
726 if (!alarmtimer_get_rtcdev())
727 return -EINVAL;
728
729 return base->get_ktime();
730 }
731
732 /**
733 * alarm_timer_create - posix timer_create interface
734 * @new_timer: k_itimer pointer to manage
735 *
736 * Initializes the k_itimer structure.
737 */
738 static int alarm_timer_create(struct k_itimer *new_timer)
739 {
740 enum alarmtimer_type type;
741
742 if (!alarmtimer_get_rtcdev())
743 return -EOPNOTSUPP;
744
745 if (!capable(CAP_WAKE_ALARM))
746 return -EPERM;
747
748 type = clock2alarm(new_timer->it_clock);
749 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
750 return 0;
751 }
752
753 /**
754 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
755 * @alarm: ptr to alarm that fired
756 * @now: time at the timer expiration
757 *
758 * Wakes up the task that set the alarmtimer
759 *
760 * Return: ALARMTIMER_NORESTART
761 */
762 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
763 ktime_t now)
764 {
765 struct task_struct *task = alarm->data;
766
767 alarm->data = NULL;
768 if (task)
769 wake_up_process(task);
770 return ALARMTIMER_NORESTART;
771 }
772
773 /**
774 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
775 * @alarm: ptr to alarmtimer
776 * @absexp: absolute expiration time
777 * @type: alarm type (BOOTTIME/REALTIME).
778 *
779 * Sets the alarm timer and sleeps until it is fired or interrupted.
780 */
781 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
782 enum alarmtimer_type type)
783 {
784 struct restart_block *restart;
785 alarm->data = (void *)current;
786 do {
787 set_current_state(TASK_INTERRUPTIBLE);
788 alarm_start(alarm, absexp);
789 if (likely(alarm->data))
790 schedule();
791
792 alarm_cancel(alarm);
793 } while (alarm->data && !signal_pending(current));
794
795 __set_current_state(TASK_RUNNING);
796
797 destroy_hrtimer_on_stack(&alarm->timer);
798
799 if (!alarm->data)
800 return 0;
801
802 if (freezing(current))
803 alarmtimer_freezerset(absexp, type);
804 restart = ¤t->restart_block;
805 if (restart->nanosleep.type != TT_NONE) {
806 struct timespec64 rmt;
807 ktime_t rem;
808
809 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
810
811 if (rem <= 0)
812 return 0;
813 rmt = ktime_to_timespec64(rem);
814
815 return nanosleep_copyout(restart, &rmt);
816 }
817 return -ERESTART_RESTARTBLOCK;
818 }
819
820 static void
821 alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
822 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
823 {
824 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
825 HRTIMER_MODE_ABS);
826 __alarm_init(alarm, type, function);
827 }
828
829 /**
830 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
831 * @restart: ptr to restart block
832 *
833 * Handles restarted clock_nanosleep calls
834 */
835 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
836 {
837 enum alarmtimer_type type = restart->nanosleep.clockid;
838 ktime_t exp = restart->nanosleep.expires;
839 struct alarm alarm;
840
841 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
842
843 return alarmtimer_do_nsleep(&alarm, exp, type);
844 }
845
846 /**
847 * alarm_timer_nsleep - alarmtimer nanosleep
848 * @which_clock: clockid
849 * @flags: determines abstime or relative
850 * @tsreq: requested sleep time (abs or rel)
851 *
852 * Handles clock_nanosleep calls against _ALARM clockids
853 */
854 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
855 const struct timespec64 *tsreq)
856 {
857 enum alarmtimer_type type = clock2alarm(which_clock);
858 struct restart_block *restart = ¤t->restart_block;
859 struct alarm alarm;
860 ktime_t exp;
861 int ret;
862
863 if (!alarmtimer_get_rtcdev())
864 return -EOPNOTSUPP;
865
866 if (flags & ~TIMER_ABSTIME)
867 return -EINVAL;
868
869 if (!capable(CAP_WAKE_ALARM))
870 return -EPERM;
871
872 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
873
874 exp = timespec64_to_ktime(*tsreq);
875 /* Convert (if necessary) to absolute time */
876 if (flags != TIMER_ABSTIME) {
877 ktime_t now = alarm_bases[type].get_ktime();
878
879 exp = ktime_add_safe(now, exp);
880 } else {
881 exp = timens_ktime_to_host(which_clock, exp);
882 }
883
884 ret = alarmtimer_do_nsleep(&alarm, exp, type);
885 if (ret != -ERESTART_RESTARTBLOCK)
886 return ret;
887
888 /* abs timers don't set remaining time or restart */
889 if (flags == TIMER_ABSTIME)
890 return -ERESTARTNOHAND;
891
892 restart->nanosleep.clockid = type;
893 restart->nanosleep.expires = exp;
894 set_restart_fn(restart, alarm_timer_nsleep_restart);
895 return ret;
896 }
897
898 const struct k_clock alarm_clock = {
899 .clock_getres = alarm_clock_getres,
900 .clock_get_ktime = alarm_clock_get_ktime,
901 .clock_get_timespec = alarm_clock_get_timespec,
902 .timer_create = alarm_timer_create,
903 .timer_set = common_timer_set,
904 .timer_del = common_timer_del,
905 .timer_get = common_timer_get,
906 .timer_arm = alarm_timer_arm,
907 .timer_rearm = alarm_timer_rearm,
908 .timer_forward = alarm_timer_forward,
909 .timer_remaining = alarm_timer_remaining,
910 .timer_try_to_cancel = alarm_timer_try_to_cancel,
911 .timer_wait_running = alarm_timer_wait_running,
912 .nsleep = alarm_timer_nsleep,
913 };
914 #endif /* CONFIG_POSIX_TIMERS */
915
916
917 /* Suspend hook structures */
918 static const struct dev_pm_ops alarmtimer_pm_ops = {
919 .suspend = alarmtimer_suspend,
920 .resume = alarmtimer_resume,
921 };
922
923 static struct platform_driver alarmtimer_driver = {
924 .driver = {
925 .name = "alarmtimer",
926 .pm = &alarmtimer_pm_ops,
927 }
928 };
929
930 static void get_boottime_timespec(struct timespec64 *tp)
931 {
932 ktime_get_boottime_ts64(tp);
933 timens_add_boottime(tp);
934 }
935
936 /**
937 * alarmtimer_init - Initialize alarm timer code
938 *
939 * This function initializes the alarm bases and registers
940 * the posix clock ids.
941 */
942 static int __init alarmtimer_init(void)
943 {
944 int error;
945 int i;
946
947 alarmtimer_rtc_timer_init();
948
949 /* Initialize alarm bases */
950 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
951 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
952 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
953 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
954 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
955 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
956 for (i = 0; i < ALARM_NUMTYPE; i++) {
957 timerqueue_init_head(&alarm_bases[i].timerqueue);
958 spin_lock_init(&alarm_bases[i].lock);
959 }
960
961 error = alarmtimer_rtc_interface_setup();
962 if (error)
963 return error;
964
965 error = platform_driver_register(&alarmtimer_driver);
966 if (error)
967 goto out_if;
968
969 return 0;
970 out_if:
971 alarmtimer_rtc_interface_remove();
972 return error;
973 }
974 device_initcall(alarmtimer_init);
975
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