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 : {
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 0 : static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
160 : {
161 0 : if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
162 0 : timerqueue_del(&base->timerqueue, &alarm->node);
163 :
164 0 : timerqueue_add(&base->timerqueue, &alarm->node);
165 0 : alarm->state |= ALARMTIMER_STATE_ENQUEUED;
166 0 : }
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 0 : if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
180 : return;
181 :
182 0 : timerqueue_del(&base->timerqueue, &alarm->node);
183 0 : 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 0 : static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
197 : {
198 0 : struct alarm *alarm = container_of(timer, struct alarm, timer);
199 0 : struct alarm_base *base = &alarm_bases[alarm->type];
200 : unsigned long flags;
201 0 : int ret = HRTIMER_NORESTART;
202 0 : int restart = ALARMTIMER_NORESTART;
203 :
204 0 : spin_lock_irqsave(&base->lock, flags);
205 0 : alarmtimer_dequeue(base, alarm);
206 0 : spin_unlock_irqrestore(&base->lock, flags);
207 :
208 0 : if (alarm->function)
209 0 : restart = alarm->function(alarm, base->get_ktime());
210 :
211 0 : spin_lock_irqsave(&base->lock, flags);
212 0 : if (restart != ALARMTIMER_NORESTART) {
213 0 : hrtimer_set_expires(&alarm->timer, alarm->node.expires);
214 0 : alarmtimer_enqueue(base, alarm);
215 0 : ret = HRTIMER_RESTART;
216 : }
217 0 : spin_unlock_irqrestore(&base->lock, flags);
218 :
219 0 : trace_alarmtimer_fired(alarm, base->get_ktime());
220 0 : return ret;
221 :
222 : }
223 :
224 0 : ktime_t alarm_expires_remaining(const struct alarm *alarm)
225 : {
226 0 : struct alarm_base *base = &alarm_bases[alarm->type];
227 0 : 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 : 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 :
302 : static 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
313 0 : static int alarmtimer_suspend(struct device *dev)
314 : {
315 0 : return 0;
316 : }
317 :
318 0 : static int alarmtimer_resume(struct device *dev)
319 : {
320 0 : return 0;
321 : }
322 : #endif
323 :
324 : static void
325 : __alarm_init(struct alarm *alarm, enum alarmtimer_type type,
326 : enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
327 : {
328 0 : timerqueue_init(&alarm->node);
329 0 : alarm->timer.function = alarmtimer_fired;
330 0 : alarm->function = function;
331 0 : alarm->type = type;
332 0 : 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 : */
341 0 : void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
342 : enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
343 : {
344 0 : hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
345 : HRTIMER_MODE_ABS);
346 0 : __alarm_init(alarm, type, function);
347 0 : }
348 : EXPORT_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 : */
355 0 : void alarm_start(struct alarm *alarm, ktime_t start)
356 : {
357 0 : struct alarm_base *base = &alarm_bases[alarm->type];
358 : unsigned long flags;
359 :
360 0 : spin_lock_irqsave(&base->lock, flags);
361 0 : alarm->node.expires = start;
362 0 : alarmtimer_enqueue(base, alarm);
363 0 : hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
364 0 : spin_unlock_irqrestore(&base->lock, flags);
365 :
366 0 : trace_alarmtimer_start(alarm, base->get_ktime());
367 0 : }
368 : EXPORT_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 : */
375 0 : void alarm_start_relative(struct alarm *alarm, ktime_t start)
376 : {
377 0 : struct alarm_base *base = &alarm_bases[alarm->type];
378 :
379 0 : start = ktime_add_safe(start, base->get_ktime());
380 0 : alarm_start(alarm, start);
381 0 : }
382 : EXPORT_SYMBOL_GPL(alarm_start_relative);
383 :
384 0 : void alarm_restart(struct alarm *alarm)
385 : {
386 0 : struct alarm_base *base = &alarm_bases[alarm->type];
387 : unsigned long flags;
388 :
389 0 : spin_lock_irqsave(&base->lock, flags);
390 0 : hrtimer_set_expires(&alarm->timer, alarm->node.expires);
391 0 : hrtimer_restart(&alarm->timer);
392 0 : alarmtimer_enqueue(base, alarm);
393 0 : spin_unlock_irqrestore(&base->lock, flags);
394 0 : }
395 : EXPORT_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 : */
404 0 : int alarm_try_to_cancel(struct alarm *alarm)
405 : {
406 0 : struct alarm_base *base = &alarm_bases[alarm->type];
407 : unsigned long flags;
408 : int ret;
409 :
410 0 : spin_lock_irqsave(&base->lock, flags);
411 0 : ret = hrtimer_try_to_cancel(&alarm->timer);
412 0 : if (ret >= 0)
413 : alarmtimer_dequeue(base, alarm);
414 0 : spin_unlock_irqrestore(&base->lock, flags);
415 :
416 0 : trace_alarmtimer_cancel(alarm, base->get_ktime());
417 0 : return ret;
418 : }
419 : EXPORT_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 : */
428 0 : int alarm_cancel(struct alarm *alarm)
429 : {
430 : for (;;) {
431 0 : int ret = alarm_try_to_cancel(alarm);
432 0 : if (ret >= 0)
433 0 : return ret;
434 0 : hrtimer_cancel_wait_running(&alarm->timer);
435 : }
436 : }
437 : EXPORT_SYMBOL_GPL(alarm_cancel);
438 :
439 :
440 0 : u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
441 : {
442 0 : u64 overrun = 1;
443 : ktime_t delta;
444 :
445 0 : delta = ktime_sub(now, alarm->node.expires);
446 :
447 0 : if (delta < 0)
448 : return 0;
449 :
450 0 : if (unlikely(delta >= interval)) {
451 0 : s64 incr = ktime_to_ns(interval);
452 :
453 0 : overrun = ktime_divns(delta, incr);
454 :
455 0 : alarm->node.expires = ktime_add_ns(alarm->node.expires,
456 : incr*overrun);
457 :
458 0 : if (alarm->node.expires > now)
459 : return overrun;
460 : /*
461 : * This (and the ktime_add() below) is the
462 : * correction for exact:
463 : */
464 0 : overrun++;
465 : }
466 :
467 0 : alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
468 0 : return overrun;
469 : }
470 : EXPORT_SYMBOL_GPL(alarm_forward);
471 :
472 : static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
473 : {
474 0 : struct alarm_base *base = &alarm_bases[alarm->type];
475 0 : 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 0 : return alarm_forward(alarm, now, interval);
496 : }
497 :
498 0 : u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
499 : {
500 0 : return __alarm_forward_now(alarm, interval, false);
501 : }
502 : EXPORT_SYMBOL_GPL(alarm_forward_now);
503 :
504 : #ifdef CONFIG_POSIX_TIMERS
505 :
506 : static 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 : */
541 : static 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 : */
559 : static 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 : */
594 0 : static void alarm_timer_rearm(struct k_itimer *timr)
595 : {
596 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
597 :
598 0 : timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
599 0 : alarm_start(alarm, alarm->node.expires);
600 0 : }
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 : */
607 0 : static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
608 : {
609 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
610 :
611 0 : 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 : */
619 0 : static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
620 : {
621 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
622 :
623 0 : 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 : */
630 0 : static int alarm_timer_try_to_cancel(struct k_itimer *timr)
631 : {
632 0 : 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 : */
643 0 : static void alarm_timer_wait_running(struct k_itimer *timr)
644 : {
645 0 : hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
646 0 : }
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 : */
655 0 : static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
656 : bool absolute, bool sigev_none)
657 : {
658 0 : struct alarm *alarm = &timr->it.alarm.alarmtimer;
659 0 : struct alarm_base *base = &alarm_bases[alarm->type];
660 :
661 0 : if (!absolute)
662 0 : expires = ktime_add_safe(expires, base->get_ktime());
663 0 : if (sigev_none)
664 0 : alarm->node.expires = expires;
665 : else
666 0 : alarm_start(&timr->it.alarm.alarmtimer, expires);
667 0 : }
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 : */
676 0 : static 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 : */
693 0 : static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
694 : {
695 0 : 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 : */
711 0 : static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
712 : {
713 0 : 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 : */
727 0 : static 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 : */
751 : static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
752 : ktime_t now)
753 : {
754 : struct task_struct *task = 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 : */
770 : static 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 = ¤t->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 :
809 : static void
810 : alarm_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 : */
824 : static 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 : */
843 0 : static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
844 : const struct timespec64 *tsreq)
845 : {
846 0 : enum alarmtimer_type type = clock2alarm(which_clock);
847 0 : struct restart_block *restart = ¤t->restart_block;
848 : struct alarm alarm;
849 : ktime_t exp;
850 : int ret;
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 :
887 : const 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 */
907 : static const struct dev_pm_ops alarmtimer_pm_ops = {
908 : .suspend = alarmtimer_suspend,
909 : .resume = alarmtimer_resume,
910 : };
911 :
912 : static struct platform_driver alarmtimer_driver = {
913 : .driver = {
914 : .name = "alarmtimer",
915 : .pm = &alarmtimer_pm_ops,
916 : }
917 : };
918 :
919 0 : static void get_boottime_timespec(struct timespec64 *tp)
920 : {
921 0 : ktime_get_boottime_ts64(tp);
922 0 : timens_add_boottime(tp);
923 0 : }
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 : */
931 1 : static int __init alarmtimer_init(void)
932 : {
933 : int error;
934 : int i;
935 :
936 : alarmtimer_rtc_timer_init();
937 :
938 : /* Initialize alarm bases */
939 1 : alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
940 1 : alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
941 1 : alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
942 1 : alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
943 1 : alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
944 1 : alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
945 3 : for (i = 0; i < ALARM_NUMTYPE; i++) {
946 4 : timerqueue_init_head(&alarm_bases[i].timerqueue);
947 2 : spin_lock_init(&alarm_bases[i].lock);
948 : }
949 :
950 1 : error = alarmtimer_rtc_interface_setup();
951 : if (error)
952 : return error;
953 :
954 1 : error = platform_driver_register(&alarmtimer_driver);
955 1 : if (error)
956 : goto out_if;
957 :
958 : return 0;
959 : out_if:
960 : alarmtimer_rtc_interface_remove();
961 0 : return error;
962 : }
963 : device_initcall(alarmtimer_init);
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