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2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/kernel/time/alarmtimer.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0
12 /*
23  * Alarmtimer interface
34  *
....@@ -10,10 +11,6 @@
1011  * Copyright (C) 2010 IBM Corperation
1112  *
1213  * Author: John Stultz <john.stultz@linaro.org>
13
- *
14
- * This program is free software; you can redistribute it and/or modify
15
- * it under the terms of the GNU General Public License version 2 as
16
- * published by the Free Software Foundation.
1714  */
1815 #include <linux/time.h>
1916 #include <linux/hrtimer.h>
....@@ -29,23 +26,28 @@
2926 #include <linux/freezer.h>
3027 #include <linux/compat.h>
3128 #include <linux/module.h>
29
+#include <linux/time_namespace.h>
3230 
3331 #include "posix-timers.h"
3432 
3533 #define CREATE_TRACE_POINTS
3634 #include <trace/events/alarmtimer.h>
3735 
36
+#undef CREATE_TRACE_POINTS
37
+#include <trace/hooks/wakeupbypass.h>
3838 /**
3939  * struct alarm_base - Alarm timer bases
4040  * @lock:		Lock for syncrhonized access to the base
4141  * @timerqueue:		Timerqueue head managing the list of events
42
- * @gettime:		Function to read the time correlating to the base
42
+ * @get_ktime:		Function to read the time correlating to the base
43
+ * @get_timespec:	Function to read the namespace time correlating to the base
4344  * @base_clockid:	clockid for the base
4445  */
4546 static struct alarm_base {
4647 	spinlock_t		lock;
4748 	struct timerqueue_head	timerqueue;
48
-	ktime_t			(*gettime)(void);
49
+	ktime_t			(*get_ktime)(void);
50
+	void			(*get_timespec)(struct timespec64 *tp);
4951 	clockid_t		base_clockid;
5052 } alarm_bases[ALARM_NUMTYPE];
5153 
....@@ -58,8 +60,6 @@
5860 #endif
5961 
6062 #ifdef CONFIG_RTC_CLASS
61
-static struct wakeup_source *ws;
62
-
6363 /* rtc timer and device for setting alarm wakeups at suspend */
6464 static struct rtc_timer		rtctimer;
6565 static struct rtc_device	*rtcdev;
....@@ -69,8 +69,6 @@
6969  * alarmtimer_get_rtcdev - Return selected rtcdevice
7070  *
7171  * This function returns the rtc device to use for wakealarms.
72
- * If one has not already been chosen, it checks to see if a
73
- * functional rtc device is available.
7472  */
7573 struct rtc_device *alarmtimer_get_rtcdev(void)
7674 {
....@@ -90,7 +88,7 @@
9088 {
9189 	unsigned long flags;
9290 	struct rtc_device *rtc = to_rtc_device(dev);
93
-	struct wakeup_source *__ws;
91
+	struct platform_device *pdev;
9492 	int ret = 0;
9593 
9694 	if (rtcdev)
....@@ -101,10 +99,13 @@
10199 	if (!device_may_wakeup(rtc->dev.parent))
102100 		return -1;
103101 
104
-	__ws = wakeup_source_register(dev, "alarmtimer");
102
+	pdev = platform_device_register_data(dev, "alarmtimer",
103
+					     PLATFORM_DEVID_AUTO, NULL, 0);
104
+	if (!IS_ERR(pdev))
105
+		device_init_wakeup(&pdev->dev, true);
105106 
106107 	spin_lock_irqsave(&rtcdev_lock, flags);
107
-	if (!rtcdev) {
108
+	if (!IS_ERR(pdev) && !rtcdev) {
108109 		if (!try_module_get(rtc->owner)) {
109110 			ret = -1;
110111 			goto unlock;
....@@ -113,13 +114,14 @@
113114 		rtcdev = rtc;
114115 		/* hold a reference so it doesn't go away */
115116 		get_device(dev);
116
-		ws = __ws;
117
-		__ws = NULL;
117
+		pdev = NULL;
118
+	} else {
119
+		ret = -1;
118120 	}
119121 unlock:
120122 	spin_unlock_irqrestore(&rtcdev_lock, flags);
121123 
122
-	wakeup_source_unregister(__ws);
124
+	platform_device_unregister(pdev);
123125 
124126 	return ret;
125127 }
....@@ -143,11 +145,6 @@
143145 	class_interface_unregister(&alarmtimer_rtc_interface);
144146 }
145147 #else
146
-struct rtc_device *alarmtimer_get_rtcdev(void)
147
-{
148
-	return NULL;
149
-}
150
-#define rtcdev (NULL)
151148 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
152149 static inline void alarmtimer_rtc_interface_remove(void) { }
153150 static inline void alarmtimer_rtc_timer_init(void) { }
....@@ -197,7 +194,7 @@
197194  * When a alarm timer fires, this runs through the timerqueue to
198195  * see which alarms expired, and runs those. If there are more alarm
199196  * timers queued for the future, we set the hrtimer to fire when
200
- * when the next future alarm timer expires.
197
+ * the next future alarm timer expires.
201198  */
202199 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
203200 {
....@@ -212,7 +209,7 @@
212209 	spin_unlock_irqrestore(&base->lock, flags);
213210 
214211 	if (alarm->function)
215
-		restart = alarm->function(alarm, base->gettime());
212
+		restart = alarm->function(alarm, base->get_ktime());
216213 
217214 	spin_lock_irqsave(&base->lock, flags);
218215 	if (restart != ALARMTIMER_NORESTART) {
....@@ -222,7 +219,7 @@
222219 	}
223220 	spin_unlock_irqrestore(&base->lock, flags);
224221 
225
-	trace_alarmtimer_fired(alarm, base->gettime());
222
+	trace_alarmtimer_fired(alarm, base->get_ktime());
226223 	return ret;
227224 
228225 }
....@@ -230,7 +227,7 @@
230227 ktime_t alarm_expires_remaining(const struct alarm *alarm)
231228 {
232229 	struct alarm_base *base = &alarm_bases[alarm->type];
233
-	return ktime_sub(alarm->node.expires, base->gettime());
230
+	return ktime_sub(alarm->node.expires, base->get_ktime());
234231 }
235232 EXPORT_SYMBOL_GPL(alarm_expires_remaining);
236233 
....@@ -238,7 +235,6 @@
238235 /**
239236  * alarmtimer_suspend - Suspend time callback
240237  * @dev: unused
241
- * @state: unused
242238  *
243239  * When we are going into suspend, we look through the bases
244240  * to see which is the soonest timer to expire. We then
....@@ -252,6 +248,7 @@
252248 	struct rtc_device *rtc;
253249 	unsigned long flags;
254250 	struct rtc_time tm;
251
+	int wakeup_bypass_enabled = 0;
255252 
256253 	spin_lock_irqsave(&freezer_delta_lock, flags);
257254 	min = freezer_delta;
....@@ -259,6 +256,10 @@
259256 	type = freezer_alarmtype;
260257 	freezer_delta = 0;
261258 	spin_unlock_irqrestore(&freezer_delta_lock, flags);
259
+
260
+	trace_android_vh_wakeup_bypass(&wakeup_bypass_enabled);
261
+	if (wakeup_bypass_enabled)
262
+		return 0;
262263 
263264 	rtc = alarmtimer_get_rtcdev();
264265 	/* If we have no rtcdev, just return */
....@@ -276,7 +277,7 @@
276277 		spin_unlock_irqrestore(&base->lock, flags);
277278 		if (!next)
278279 			continue;
279
-		delta = ktime_sub(next->expires, base->gettime());
280
+		delta = ktime_sub(next->expires, base->get_ktime());
280281 		if (!min || (delta < min)) {
281282 			expires = next->expires;
282283 			min = delta;
....@@ -287,7 +288,7 @@
287288 		return 0;
288289 
289290 	if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
290
-		__pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
291
+		pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
291292 		return -EBUSY;
292293 	}
293294 
....@@ -302,7 +303,7 @@
302303 	/* Set alarm, if in the past reject suspend briefly to handle */
303304 	ret = rtc_timer_start(rtc, &rtctimer, now, 0);
304305 	if (ret < 0)
305
-		__pm_wakeup_event(ws, MSEC_PER_SEC);
306
+		pm_wakeup_event(dev, MSEC_PER_SEC);
306307 	return ret;
307308 }
308309 
....@@ -370,7 +371,7 @@
370371 	hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
371372 	spin_unlock_irqrestore(&base->lock, flags);
372373 
373
-	trace_alarmtimer_start(alarm, base->gettime());
374
+	trace_alarmtimer_start(alarm, base->get_ktime());
374375 }
375376 EXPORT_SYMBOL_GPL(alarm_start);
376377 
....@@ -383,7 +384,7 @@
383384 {
384385 	struct alarm_base *base = &alarm_bases[alarm->type];
385386 
386
-	start = ktime_add_safe(start, base->gettime());
387
+	start = ktime_add_safe(start, base->get_ktime());
387388 	alarm_start(alarm, start);
388389 }
389390 EXPORT_SYMBOL_GPL(alarm_start_relative);
....@@ -420,7 +421,7 @@
420421 		alarmtimer_dequeue(base, alarm);
421422 	spin_unlock_irqrestore(&base->lock, flags);
422423 
423
-	trace_alarmtimer_cancel(alarm, base->gettime());
424
+	trace_alarmtimer_cancel(alarm, base->get_ktime());
424425 	return ret;
425426 }
426427 EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
....@@ -438,7 +439,7 @@
438439 		int ret = alarm_try_to_cancel(alarm);
439440 		if (ret >= 0)
440441 			return ret;
441
-		hrtimer_grab_expiry_lock(&alarm->timer);
442
+		hrtimer_cancel_wait_running(&alarm->timer);
442443 	}
443444 }
444445 EXPORT_SYMBOL_GPL(alarm_cancel);
....@@ -476,11 +477,35 @@
476477 }
477478 EXPORT_SYMBOL_GPL(alarm_forward);
478479 
479
-u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
480
+static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
480481 {
481482 	struct alarm_base *base = &alarm_bases[alarm->type];
483
+	ktime_t now = base->get_ktime();
482484 
483
-	return alarm_forward(alarm, base->gettime(), interval);
485
+	if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) {
486
+		/*
487
+		 * Same issue as with posix_timer_fn(). Timers which are
488
+		 * periodic but the signal is ignored can starve the system
489
+		 * with a very small interval. The real fix which was
490
+		 * promised in the context of posix_timer_fn() never
491
+		 * materialized, but someone should really work on it.
492
+		 *
493
+		 * To prevent DOS fake @now to be 1 jiffie out which keeps
494
+		 * the overrun accounting correct but creates an
495
+		 * inconsistency vs. timer_gettime(2).
496
+		 */
497
+		ktime_t kj = NSEC_PER_SEC / HZ;
498
+
499
+		if (interval < kj)
500
+			now = ktime_add(now, kj);
501
+	}
502
+
503
+	return alarm_forward(alarm, now, interval);
504
+}
505
+
506
+u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
507
+{
508
+	return __alarm_forward_now(alarm, interval, false);
484509 }
485510 EXPORT_SYMBOL_GPL(alarm_forward_now);
486511 
....@@ -506,7 +531,7 @@
506531 		return;
507532 	}
508533 
509
-	delta = ktime_sub(absexp, base->gettime());
534
+	delta = ktime_sub(absexp, base->get_ktime());
510535 
511536 	spin_lock_irqsave(&freezer_delta_lock, flags);
512537 	if (!freezer_delta || (delta < freezer_delta)) {
....@@ -554,9 +579,10 @@
554579 	if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
555580 		/*
556581 		 * Handle ignored signals and rearm the timer. This will go
557
-		 * away once we handle ignored signals proper.
582
+		 * away once we handle ignored signals proper. Ensure that
583
+		 * small intervals cannot starve the system.
558584 		 */
559
-		ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
585
+		ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
560586 		++ptr->it_requeue_pending;
561587 		ptr->it_active = 1;
562588 		result = ALARMTIMER_RESTART;
....@@ -612,6 +638,19 @@
612638 }
613639 
614640 /**
641
+ * alarm_timer_wait_running - Posix timer callback to wait for a timer
642
+ * @timr:	Pointer to the posixtimer data struct
643
+ *
644
+ * Called from the core code when timer cancel detected that the callback
645
+ * is running. @timr is unlocked and rcu read lock is held to prevent it
646
+ * from being freed.
647
+ */
648
+static void alarm_timer_wait_running(struct k_itimer *timr)
649
+{
650
+	hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
651
+}
652
+
653
+/**
615654  * alarm_timer_arm - Posix timer callback to arm a timer
616655  * @timr:	Pointer to the posixtimer data struct
617656  * @expires:	The new expiry time
....@@ -625,7 +664,7 @@
625664 	struct alarm_base *base = &alarm_bases[alarm->type];
626665 
627666 	if (!absolute)
628
-		expires = ktime_add_safe(expires, base->gettime());
667
+		expires = ktime_add_safe(expires, base->get_ktime());
629668 	if (sigev_none)
630669 		alarm->node.expires = expires;
631670 	else
....@@ -650,21 +689,38 @@
650689 }
651690 
652691 /**
653
- * alarm_clock_get - posix clock_get interface
692
+ * alarm_clock_get_timespec - posix clock_get_timespec interface
654693  * @which_clock: clockid
655694  * @tp: timespec to fill.
656695  *
657
- * Provides the underlying alarm base time.
696
+ * Provides the underlying alarm base time in a tasks time namespace.
658697  */
659
-static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
698
+static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
660699 {
661700 	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
662701 
663702 	if (!alarmtimer_get_rtcdev())
664703 		return -EINVAL;
665704 
666
-	*tp = ktime_to_timespec64(base->gettime());
705
+	base->get_timespec(tp);
706
+
667707 	return 0;
708
+}
709
+
710
+/**
711
+ * alarm_clock_get_ktime - posix clock_get_ktime interface
712
+ * @which_clock: clockid
713
+ *
714
+ * Provides the underlying alarm base time in the root namespace.
715
+ */
716
+static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
717
+{
718
+	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
719
+
720
+	if (!alarmtimer_get_rtcdev())
721
+		return -EINVAL;
722
+
723
+	return base->get_ktime();
668724 }
669725 
670726 /**
....@@ -740,7 +796,7 @@
740796 		struct timespec64 rmt;
741797 		ktime_t rem;
742798 
743
-		rem = ktime_sub(absexp, alarm_bases[type].gettime());
799
+		rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
744800 
745801 		if (rem <= 0)
746802 			return 0;
....@@ -809,9 +865,11 @@
809865 	exp = timespec64_to_ktime(*tsreq);
810866 	/* Convert (if necessary) to absolute time */
811867 	if (flags != TIMER_ABSTIME) {
812
-		ktime_t now = alarm_bases[type].gettime();
868
+		ktime_t now = alarm_bases[type].get_ktime();
813869 
814870 		exp = ktime_add_safe(now, exp);
871
+	} else {
872
+		exp = timens_ktime_to_host(which_clock, exp);
815873 	}
816874 
817875 	ret = alarmtimer_do_nsleep(&alarm, exp, type);
....@@ -830,7 +888,8 @@
830888 
831889 const struct k_clock alarm_clock = {
832890 	.clock_getres		= alarm_clock_getres,
833
-	.clock_get		= alarm_clock_get,
891
+	.clock_get_ktime	= alarm_clock_get_ktime,
892
+	.clock_get_timespec	= alarm_clock_get_timespec,
834893 	.timer_create		= alarm_timer_create,
835894 	.timer_set		= common_timer_set,
836895 	.timer_del		= common_timer_del,
....@@ -840,6 +899,7 @@
840899 	.timer_forward		= alarm_timer_forward,
841900 	.timer_remaining	= alarm_timer_remaining,
842901 	.timer_try_to_cancel	= alarm_timer_try_to_cancel,
902
+	.timer_wait_running	= alarm_timer_wait_running,
843903 	.nsleep			= alarm_timer_nsleep,
844904 };
845905 #endif /* CONFIG_POSIX_TIMERS */
....@@ -858,6 +918,12 @@
858918 	}
859919 };
860920 
921
+static void get_boottime_timespec(struct timespec64 *tp)
922
+{
923
+	ktime_get_boottime_ts64(tp);
924
+	timens_add_boottime(tp);
925
+}
926
+
861927 /**
862928  * alarmtimer_init - Initialize alarm timer code
863929  *
....@@ -866,17 +932,18 @@
866932  */
867933 static int __init alarmtimer_init(void)
868934 {
869
-	struct platform_device *pdev;
870
-	int error = 0;
935
+	int error;
871936 	int i;
872937 
873938 	alarmtimer_rtc_timer_init();
874939 
875940 	/* Initialize alarm bases */
876941 	alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
877
-	alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
942
+	alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
943
+	alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
878944 	alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
879
-	alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
945
+	alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
946
+	alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
880947 	for (i = 0; i < ALARM_NUMTYPE; i++) {
881948 		timerqueue_init_head(&alarm_bases[i].timerqueue);
882949 		spin_lock_init(&alarm_bases[i].lock);
....@@ -890,15 +957,7 @@
890957 	if (error)
891958 		goto out_if;
892959 
893
-	pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
894
-	if (IS_ERR(pdev)) {
895
-		error = PTR_ERR(pdev);
896
-		goto out_drv;
897
-	}
898960 	return 0;
899
-
900
-out_drv:
901
-	platform_driver_unregister(&alarmtimer_driver);
902961 out_if:
903962 	alarmtimer_rtc_interface_remove();
904963 	return error;