Line data Source code
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 : 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 : }
119 : unlock:
120 : spin_unlock_irqrestore(&rtcdev_lock, flags);
121 :
122 : platform_device_unregister(pdev);
123 :
124 : return ret;
125 : }
126 :
127 : static inline void alarmtimer_rtc_timer_init(void)
128 : {
129 : rtc_timer_init(&rtctimer, NULL, NULL);
130 : }
131 :
132 : static struct class_interface alarmtimer_rtc_interface = {
133 : .add_dev = &alarmtimer_rtc_add_device,
134 : };
135 :
136 : static int alarmtimer_rtc_interface_setup(void)
137 : {
138 : alarmtimer_rtc_interface.class = rtc_class;
139 : return class_interface_register(&alarmtimer_rtc_interface);
140 : }
141 : static void alarmtimer_rtc_interface_remove(void)
142 : {
143 : class_interface_unregister(&alarmtimer_rtc_interface);
144 : }
145 : #else
146 : static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
147 : static inline void alarmtimer_rtc_interface_remove(void) { }
148 : static 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 : */
160 0 : static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
161 : {
162 0 : if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
163 0 : timerqueue_del(&base->timerqueue, &alarm->node);
164 :
165 0 : timerqueue_add(&base->timerqueue, &alarm->node);
166 0 : alarm->state |= ALARMTIMER_STATE_ENQUEUED;
167 0 : }
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 : */
178 : static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
179 : {
180 0 : if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
181 : return;
182 :
183 0 : timerqueue_del(&base->timerqueue, &alarm->node);
184 0 : 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 : */
197 0 : static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
198 : {
199 0 : struct alarm *alarm = container_of(timer, struct alarm, timer);
200 0 : struct alarm_base *base = &alarm_bases[alarm->type];
201 : unsigned long flags;
202 0 : int ret = HRTIMER_NORESTART;
203 0 : int restart = ALARMTIMER_NORESTART;
204 :
205 0 : spin_lock_irqsave(&base->lock, flags);
206 0 : alarmtimer_dequeue(base, alarm);
207 0 : spin_unlock_irqrestore(&base->lock, flags);
208 :
209 0 : if (alarm->function)
210 0 : restart = alarm->function(alarm, base->get_ktime());
211 :
212 0 : spin_lock_irqsave(&base->lock, flags);
213 0 : if (restart != ALARMTIMER_NORESTART) {
214 0 : hrtimer_set_expires(&alarm->timer, alarm->node.expires);
215 0 : alarmtimer_enqueue(base, alarm);
216 0 : ret = HRTIMER_RESTART;
217 : }
218 0 : spin_unlock_irqrestore(&base->lock, flags);
219 :
220 0 : trace_alarmtimer_fired(alarm, base->get_ktime());
221 0 : return ret;
222 :
223 : }
224 :
225 0 : ktime_t alarm_expires_remaining(const struct alarm *alarm)
226 : {
227 0 : struct alarm_base *base = &alarm_bases[alarm->type];
228 0 : return ktime_sub(alarm->node.expires, base->get_ktime());
229 : }
230 : EXPORT_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 : */
242 : static 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 :
303 : static 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
314 0 : static int alarmtimer_suspend(struct device *dev)
315 : {
316 0 : return 0;
317 : }
318 :
319 0 : static int alarmtimer_resume(struct device *dev)
320 : {
321 0 : return 0;
322 : }
323 : #endif
324 :
325 : static void
326 : __alarm_init(struct alarm *alarm, enum alarmtimer_type type,
327 : enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
328 : {
329 0 : timerqueue_init(&alarm->node);
330 0 : alarm->timer.function = alarmtimer_fired;
331 0 : alarm->function = function;
332 0 : alarm->type = type;
333 0 : 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 : */
342 0 : void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
343 : enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
344 : {
345 0 : hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
346 : HRTIMER_MODE_ABS);
347 0 : __alarm_init(alarm, type, function);
348 0 : }
349 : EXPORT_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 : */
356 0 : void alarm_start(struct alarm *alarm, ktime_t start)
357 : {
358 0 : struct alarm_base *base = &alarm_bases[alarm->type];
359 : unsigned long flags;
360 :
361 0 : spin_lock_irqsave(&base->lock, flags);
362 0 : alarm->node.expires = start;
363 0 : alarmtimer_enqueue(base, alarm);
364 0 : hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
365 0 : spin_unlock_irqrestore(&base->lock, flags);
366 :
367 0 : trace_alarmtimer_start(alarm, base->get_ktime());
368 0 : }
369 : EXPORT_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 : */
376 0 : void alarm_start_relative(struct alarm *alarm, ktime_t start)
377 : {
378 0 : struct alarm_base *base = &alarm_bases[alarm->type];
379 :
380 0 : start = ktime_add_safe(start, base->get_ktime());
381 0 : alarm_start(alarm, start);
382 0 : }
383 : EXPORT_SYMBOL_GPL(alarm_start_relative);
384 :
385 0 : void alarm_restart(struct alarm *alarm)
386 : {
387 0 : struct alarm_base *base = &alarm_bases[alarm->type];
388 : unsigned long flags;
389 :
390 0 : spin_lock_irqsave(&base->lock, flags);
391 0 : hrtimer_set_expires(&alarm->timer, alarm->node.expires);
392 0 : hrtimer_restart(&alarm->timer);
393 0 : alarmtimer_enqueue(base, alarm);
394 0 : spin_unlock_irqrestore(&base->lock, flags);
395 0 : }
396 : EXPORT_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 : */
405 0 : int alarm_try_to_cancel(struct alarm *alarm)
406 : {
407 0 : struct alarm_base *base = &alarm_bases[alarm->type];
408 : unsigned long flags;
409 : int ret;
410 :
411 0 : spin_lock_irqsave(&base->lock, flags);
412 0 : ret = hrtimer_try_to_cancel(&alarm->timer);
413 0 : if (ret >= 0)
414 : alarmtimer_dequeue(base, alarm);
415 0 : spin_unlock_irqrestore(&base->lock, flags);
416 :
417 0 : trace_alarmtimer_cancel(alarm, base->get_ktime());
418 0 : return ret;
419 : }
420 : EXPORT_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 : */
429 0 : int alarm_cancel(struct alarm *alarm)
430 : {
431 : for (;;) {
432 0 : int ret = alarm_try_to_cancel(alarm);
433 0 : if (ret >= 0)
434 0 : return ret;
435 0 : hrtimer_cancel_wait_running(&alarm->timer);
436 : }
437 : }
438 : EXPORT_SYMBOL_GPL(alarm_cancel);
439 :
440 :
441 0 : u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
442 : {
443 0 : u64 overrun = 1;
444 : ktime_t delta;
445 :
446 0 : delta = ktime_sub(now, alarm->node.expires);
447 :
448 0 : if (delta < 0)
449 : return 0;
450 :
451 0 : if (unlikely(delta >= interval)) {
452 0 : s64 incr = ktime_to_ns(interval);
453 :
454 0 : overrun = ktime_divns(delta, incr);
455 :
456 0 : alarm->node.expires = ktime_add_ns(alarm->node.expires,
457 : incr*overrun);
458 :
459 0 : if (alarm->node.expires > now)
460 : return overrun;
461 : /*
462 : * This (and the ktime_add() below) is the
463 : * correction for exact:
464 : */
465 0 : overrun++;
466 : }
467 :
468 0 : alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
469 0 : return overrun;
470 : }
471 : EXPORT_SYMBOL_GPL(alarm_forward);
472 :
473 : static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
474 : {
475 0 : struct alarm_base *base = &alarm_bases[alarm->type];
476 0 : 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 0 : return alarm_forward(alarm, now, interval);
497 : }
498 :
499 0 : u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
500 : {
501 0 : return __alarm_forward_now(alarm, interval, false);
502 : }
503 : EXPORT_SYMBOL_GPL(alarm_forward_now);
504 :
505 : #ifdef CONFIG_POSIX_TIMERS
506 :
507 : static 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 : */
542 : static 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 : */
560 : static 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 : */
595 0 : static void alarm_timer_rearm(struct k_itimer *timr)
596 : {
597 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
598 :
599 0 : timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
600 0 : alarm_start(alarm, alarm->node.expires);
601 0 : }
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 : */
608 0 : static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
609 : {
610 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
611 :
612 0 : 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 : */
620 0 : static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
621 : {
622 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
623 :
624 0 : 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 : */
631 0 : static int alarm_timer_try_to_cancel(struct k_itimer *timr)
632 : {
633 0 : 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 : */
644 0 : static void alarm_timer_wait_running(struct k_itimer *timr)
645 : {
646 0 : hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
647 0 : }
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 : */
656 0 : static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
657 : bool absolute, bool sigev_none)
658 : {
659 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
660 0 : struct alarm_base *base = &alarm_bases[alarm->type];
661 :
662 0 : if (!absolute)
663 0 : expires = ktime_add_safe(expires, base->get_ktime());
664 0 : if (sigev_none)
665 0 : alarm->node.expires = expires;
666 : else
667 0 : alarm_start(&timr->it.alarm.alarmtimer, expires);
668 0 : }
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 : */
677 0 : static 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 : */
694 0 : static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
695 : {
696 0 : 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 : */
712 0 : static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
713 : {
714 0 : 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 : */
728 0 : static 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 : */
752 : static 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 : */
771 : static 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 :
810 : static void
811 : alarm_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 : */
825 : static 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 : */
844 0 : static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
845 : const struct timespec64 *tsreq)
846 : {
847 0 : enum alarmtimer_type type = clock2alarm(which_clock);
848 0 : struct restart_block *restart = ¤t->restart_block;
849 : struct alarm alarm;
850 : ktime_t exp;
851 0 : 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 :
888 : const 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 */
908 : static const struct dev_pm_ops alarmtimer_pm_ops = {
909 : .suspend = alarmtimer_suspend,
910 : .resume = alarmtimer_resume,
911 : };
912 :
913 : static struct platform_driver alarmtimer_driver = {
914 : .driver = {
915 : .name = "alarmtimer",
916 : .pm = &alarmtimer_pm_ops,
917 : }
918 : };
919 :
920 0 : static void get_boottime_timespec(struct timespec64 *tp)
921 : {
922 0 : ktime_get_boottime_ts64(tp);
923 0 : timens_add_boottime(tp);
924 0 : }
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 : */
932 1 : static int __init alarmtimer_init(void)
933 : {
934 : int error;
935 : int i;
936 :
937 : alarmtimer_rtc_timer_init();
938 :
939 : /* Initialize alarm bases */
940 1 : alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
941 1 : alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
942 1 : alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
943 1 : alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
944 1 : alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
945 1 : alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
946 3 : for (i = 0; i < ALARM_NUMTYPE; i++) {
947 4 : timerqueue_init_head(&alarm_bases[i].timerqueue);
948 2 : spin_lock_init(&alarm_bases[i].lock);
949 : }
950 :
951 1 : error = alarmtimer_rtc_interface_setup();
952 : if (error)
953 : return error;
954 :
955 1 : error = platform_driver_register(&alarmtimer_driver);
956 1 : if (error)
957 : goto out_if;
958 :
959 : return 0;
960 : out_if:
961 : alarmtimer_rtc_interface_remove();
962 0 : return error;
963 : }
964 : device_initcall(alarmtimer_init);
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