diff options
Diffstat (limited to 'kernel/time/alarmtimer.c')
| -rw-r--r-- | kernel/time/alarmtimer.c | 963 |
1 files changed, 963 insertions, 0 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c new file mode 100644 index 0000000000..8d9f13d847 --- /dev/null +++ b/kernel/time/alarmtimer.c @@ -0,0 +1,963 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Alarmtimer interface + * + * This interface provides a timer which is similar to hrtimers, + * but triggers a RTC alarm if the box is suspend. + * + * This interface is influenced by the Android RTC Alarm timer + * interface. + * + * Copyright (C) 2010 IBM Corporation + * + * Author: John Stultz <john.stultz@linaro.org> + */ +#include <linux/time.h> +#include <linux/hrtimer.h> +#include <linux/timerqueue.h> +#include <linux/rtc.h> +#include <linux/sched/signal.h> +#include <linux/sched/debug.h> +#include <linux/alarmtimer.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/posix-timers.h> +#include <linux/workqueue.h> +#include <linux/freezer.h> +#include <linux/compat.h> +#include <linux/module.h> +#include <linux/time_namespace.h> + +#include "posix-timers.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/alarmtimer.h> + +/** + * struct alarm_base - Alarm timer bases + * @lock: Lock for syncrhonized access to the base + * @timerqueue: Timerqueue head managing the list of events + * @get_ktime: Function to read the time correlating to the base + * @get_timespec: Function to read the namespace time correlating to the base + * @base_clockid: clockid for the base + */ +static struct alarm_base { + spinlock_t lock; + struct timerqueue_head timerqueue; + ktime_t (*get_ktime)(void); + void (*get_timespec)(struct timespec64 *tp); + clockid_t base_clockid; +} alarm_bases[ALARM_NUMTYPE]; + +#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS) +/* freezer information to handle clock_nanosleep triggered wakeups */ +static enum alarmtimer_type freezer_alarmtype; +static ktime_t freezer_expires; +static ktime_t freezer_delta; +static DEFINE_SPINLOCK(freezer_delta_lock); +#endif + +#ifdef CONFIG_RTC_CLASS +/* rtc timer and device for setting alarm wakeups at suspend */ +static struct rtc_timer rtctimer; +static struct rtc_device *rtcdev; +static DEFINE_SPINLOCK(rtcdev_lock); + +/** + * alarmtimer_get_rtcdev - Return selected rtcdevice + * + * This function returns the rtc device to use for wakealarms. + */ +struct rtc_device *alarmtimer_get_rtcdev(void) +{ + unsigned long flags; + struct rtc_device *ret; + + spin_lock_irqsave(&rtcdev_lock, flags); + ret = rtcdev; + spin_unlock_irqrestore(&rtcdev_lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev); + +static int alarmtimer_rtc_add_device(struct device *dev) +{ + unsigned long flags; + struct rtc_device *rtc = to_rtc_device(dev); + struct platform_device *pdev; + int ret = 0; + + if (rtcdev) + return -EBUSY; + + if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) + return -1; + if (!device_may_wakeup(rtc->dev.parent)) + return -1; + + pdev = platform_device_register_data(dev, "alarmtimer", + PLATFORM_DEVID_AUTO, NULL, 0); + if (!IS_ERR(pdev)) + device_init_wakeup(&pdev->dev, true); + + spin_lock_irqsave(&rtcdev_lock, flags); + if (!IS_ERR(pdev) && !rtcdev) { + if (!try_module_get(rtc->owner)) { + ret = -1; + goto unlock; + } + + rtcdev = rtc; + /* hold a reference so it doesn't go away */ + get_device(dev); + pdev = NULL; + } else { + ret = -1; + } +unlock: + spin_unlock_irqrestore(&rtcdev_lock, flags); + + platform_device_unregister(pdev); + + return ret; +} + +static inline void alarmtimer_rtc_timer_init(void) +{ + rtc_timer_init(&rtctimer, NULL, NULL); +} + +static struct class_interface alarmtimer_rtc_interface = { + .add_dev = &alarmtimer_rtc_add_device, +}; + +static int alarmtimer_rtc_interface_setup(void) +{ + alarmtimer_rtc_interface.class = rtc_class; + return class_interface_register(&alarmtimer_rtc_interface); +} +static void alarmtimer_rtc_interface_remove(void) +{ + class_interface_unregister(&alarmtimer_rtc_interface); +} +#else +static inline int alarmtimer_rtc_interface_setup(void) { return 0; } +static inline void alarmtimer_rtc_interface_remove(void) { } +static inline void alarmtimer_rtc_timer_init(void) { } +#endif + +/** + * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue + * @base: pointer to the base where the timer is being run + * @alarm: pointer to alarm being enqueued. + * + * Adds alarm to a alarm_base timerqueue + * + * Must hold base->lock when calling. + */ +static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) +{ + if (alarm->state & ALARMTIMER_STATE_ENQUEUED) + timerqueue_del(&base->timerqueue, &alarm->node); + + timerqueue_add(&base->timerqueue, &alarm->node); + alarm->state |= ALARMTIMER_STATE_ENQUEUED; +} + +/** + * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue + * @base: pointer to the base where the timer is running + * @alarm: pointer to alarm being removed + * + * Removes alarm to a alarm_base timerqueue + * + * Must hold base->lock when calling. + */ +static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm) +{ + if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED)) + return; + + timerqueue_del(&base->timerqueue, &alarm->node); + alarm->state &= ~ALARMTIMER_STATE_ENQUEUED; +} + + +/** + * alarmtimer_fired - Handles alarm hrtimer being fired. + * @timer: pointer to hrtimer being run + * + * When a alarm timer fires, this runs through the timerqueue to + * see which alarms expired, and runs those. If there are more alarm + * timers queued for the future, we set the hrtimer to fire when + * the next future alarm timer expires. + */ +static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) +{ + struct alarm *alarm = container_of(timer, struct alarm, timer); + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + int ret = HRTIMER_NORESTART; + int restart = ALARMTIMER_NORESTART; + + spin_lock_irqsave(&base->lock, flags); + alarmtimer_dequeue(base, alarm); + spin_unlock_irqrestore(&base->lock, flags); + + if (alarm->function) + restart = alarm->function(alarm, base->get_ktime()); + + spin_lock_irqsave(&base->lock, flags); + if (restart != ALARMTIMER_NORESTART) { + hrtimer_set_expires(&alarm->timer, alarm->node.expires); + alarmtimer_enqueue(base, alarm); + ret = HRTIMER_RESTART; + } + spin_unlock_irqrestore(&base->lock, flags); + + trace_alarmtimer_fired(alarm, base->get_ktime()); + return ret; + +} + +ktime_t alarm_expires_remaining(const struct alarm *alarm) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + return ktime_sub(alarm->node.expires, base->get_ktime()); +} +EXPORT_SYMBOL_GPL(alarm_expires_remaining); + +#ifdef CONFIG_RTC_CLASS +/** + * alarmtimer_suspend - Suspend time callback + * @dev: unused + * + * When we are going into suspend, we look through the bases + * to see which is the soonest timer to expire. We then + * set an rtc timer to fire that far into the future, which + * will wake us from suspend. + */ +static int alarmtimer_suspend(struct device *dev) +{ + ktime_t min, now, expires; + int i, ret, type; + struct rtc_device *rtc; + unsigned long flags; + struct rtc_time tm; + + spin_lock_irqsave(&freezer_delta_lock, flags); + min = freezer_delta; + expires = freezer_expires; + type = freezer_alarmtype; + freezer_delta = 0; + spin_unlock_irqrestore(&freezer_delta_lock, flags); + + rtc = alarmtimer_get_rtcdev(); + /* If we have no rtcdev, just return */ + if (!rtc) + return 0; + + /* Find the soonest timer to expire*/ + for (i = 0; i < ALARM_NUMTYPE; i++) { + struct alarm_base *base = &alarm_bases[i]; + struct timerqueue_node *next; + ktime_t delta; + + spin_lock_irqsave(&base->lock, flags); + next = timerqueue_getnext(&base->timerqueue); + spin_unlock_irqrestore(&base->lock, flags); + if (!next) + continue; + delta = ktime_sub(next->expires, base->get_ktime()); + if (!min || (delta < min)) { + expires = next->expires; + min = delta; + type = i; + } + } + if (min == 0) + return 0; + + if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) { + pm_wakeup_event(dev, 2 * MSEC_PER_SEC); + return -EBUSY; + } + + trace_alarmtimer_suspend(expires, type); + + /* Setup an rtc timer to fire that far in the future */ + rtc_timer_cancel(rtc, &rtctimer); + rtc_read_time(rtc, &tm); + now = rtc_tm_to_ktime(tm); + now = ktime_add(now, min); + + /* Set alarm, if in the past reject suspend briefly to handle */ + ret = rtc_timer_start(rtc, &rtctimer, now, 0); + if (ret < 0) + pm_wakeup_event(dev, MSEC_PER_SEC); + return ret; +} + +static int alarmtimer_resume(struct device *dev) +{ + struct rtc_device *rtc; + + rtc = alarmtimer_get_rtcdev(); + if (rtc) + rtc_timer_cancel(rtc, &rtctimer); + return 0; +} + +#else +static int alarmtimer_suspend(struct device *dev) +{ + return 0; +} + +static int alarmtimer_resume(struct device *dev) +{ + return 0; +} +#endif + +static void +__alarm_init(struct alarm *alarm, enum alarmtimer_type type, + enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) +{ + timerqueue_init(&alarm->node); + alarm->timer.function = alarmtimer_fired; + alarm->function = function; + alarm->type = type; + alarm->state = ALARMTIMER_STATE_INACTIVE; +} + +/** + * alarm_init - Initialize an alarm structure + * @alarm: ptr to alarm to be initialized + * @type: the type of the alarm + * @function: callback that is run when the alarm fires + */ +void alarm_init(struct alarm *alarm, enum alarmtimer_type type, + enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) +{ + hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid, + HRTIMER_MODE_ABS); + __alarm_init(alarm, type, function); +} +EXPORT_SYMBOL_GPL(alarm_init); + +/** + * alarm_start - Sets an absolute alarm to fire + * @alarm: ptr to alarm to set + * @start: time to run the alarm + */ +void alarm_start(struct alarm *alarm, ktime_t start) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + + spin_lock_irqsave(&base->lock, flags); + alarm->node.expires = start; + alarmtimer_enqueue(base, alarm); + hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS); + spin_unlock_irqrestore(&base->lock, flags); + + trace_alarmtimer_start(alarm, base->get_ktime()); +} +EXPORT_SYMBOL_GPL(alarm_start); + +/** + * alarm_start_relative - Sets a relative alarm to fire + * @alarm: ptr to alarm to set + * @start: time relative to now to run the alarm + */ +void alarm_start_relative(struct alarm *alarm, ktime_t start) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + + start = ktime_add_safe(start, base->get_ktime()); + alarm_start(alarm, start); +} +EXPORT_SYMBOL_GPL(alarm_start_relative); + +void alarm_restart(struct alarm *alarm) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + + spin_lock_irqsave(&base->lock, flags); + hrtimer_set_expires(&alarm->timer, alarm->node.expires); + hrtimer_restart(&alarm->timer); + alarmtimer_enqueue(base, alarm); + spin_unlock_irqrestore(&base->lock, flags); +} +EXPORT_SYMBOL_GPL(alarm_restart); + +/** + * alarm_try_to_cancel - Tries to cancel an alarm timer + * @alarm: ptr to alarm to be canceled + * + * Returns 1 if the timer was canceled, 0 if it was not running, + * and -1 if the callback was running + */ +int alarm_try_to_cancel(struct alarm *alarm) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + unsigned long flags; + int ret; + + spin_lock_irqsave(&base->lock, flags); + ret = hrtimer_try_to_cancel(&alarm->timer); + if (ret >= 0) + alarmtimer_dequeue(base, alarm); + spin_unlock_irqrestore(&base->lock, flags); + + trace_alarmtimer_cancel(alarm, base->get_ktime()); + return ret; +} +EXPORT_SYMBOL_GPL(alarm_try_to_cancel); + + +/** + * alarm_cancel - Spins trying to cancel an alarm timer until it is done + * @alarm: ptr to alarm to be canceled + * + * Returns 1 if the timer was canceled, 0 if it was not active. + */ +int alarm_cancel(struct alarm *alarm) +{ + for (;;) { + int ret = alarm_try_to_cancel(alarm); + if (ret >= 0) + return ret; + hrtimer_cancel_wait_running(&alarm->timer); + } +} +EXPORT_SYMBOL_GPL(alarm_cancel); + + +u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval) +{ + u64 overrun = 1; + ktime_t delta; + + delta = ktime_sub(now, alarm->node.expires); + + if (delta < 0) + return 0; + + if (unlikely(delta >= interval)) { + s64 incr = ktime_to_ns(interval); + + overrun = ktime_divns(delta, incr); + + alarm->node.expires = ktime_add_ns(alarm->node.expires, + incr*overrun); + + if (alarm->node.expires > now) + return overrun; + /* + * This (and the ktime_add() below) is the + * correction for exact: + */ + overrun++; + } + + alarm->node.expires = ktime_add_safe(alarm->node.expires, interval); + return overrun; +} +EXPORT_SYMBOL_GPL(alarm_forward); + +static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle) +{ + struct alarm_base *base = &alarm_bases[alarm->type]; + ktime_t now = base->get_ktime(); + + if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) { + /* + * Same issue as with posix_timer_fn(). Timers which are + * periodic but the signal is ignored can starve the system + * with a very small interval. The real fix which was + * promised in the context of posix_timer_fn() never + * materialized, but someone should really work on it. + * + * To prevent DOS fake @now to be 1 jiffie out which keeps + * the overrun accounting correct but creates an + * inconsistency vs. timer_gettime(2). + */ + ktime_t kj = NSEC_PER_SEC / HZ; + + if (interval < kj) + now = ktime_add(now, kj); + } + + return alarm_forward(alarm, now, interval); +} + +u64 alarm_forward_now(struct alarm *alarm, ktime_t interval) +{ + return __alarm_forward_now(alarm, interval, false); +} +EXPORT_SYMBOL_GPL(alarm_forward_now); + +#ifdef CONFIG_POSIX_TIMERS + +static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) +{ + struct alarm_base *base; + unsigned long flags; + ktime_t delta; + + switch(type) { + case ALARM_REALTIME: + base = &alarm_bases[ALARM_REALTIME]; + type = ALARM_REALTIME_FREEZER; + break; + case ALARM_BOOTTIME: + base = &alarm_bases[ALARM_BOOTTIME]; + type = ALARM_BOOTTIME_FREEZER; + break; + default: + WARN_ONCE(1, "Invalid alarm type: %d\n", type); + return; + } + + delta = ktime_sub(absexp, base->get_ktime()); + + spin_lock_irqsave(&freezer_delta_lock, flags); + if (!freezer_delta || (delta < freezer_delta)) { + freezer_delta = delta; + freezer_expires = absexp; + freezer_alarmtype = type; + } + spin_unlock_irqrestore(&freezer_delta_lock, flags); +} + +/** + * clock2alarm - helper that converts from clockid to alarmtypes + * @clockid: clockid. + */ +static enum alarmtimer_type clock2alarm(clockid_t clockid) +{ + if (clockid == CLOCK_REALTIME_ALARM) + return ALARM_REALTIME; + if (clockid == CLOCK_BOOTTIME_ALARM) + return ALARM_BOOTTIME; + return -1; +} + +/** + * alarm_handle_timer - Callback for posix timers + * @alarm: alarm that fired + * @now: time at the timer expiration + * + * Posix timer callback for expired alarm timers. + * + * Return: whether the timer is to be restarted + */ +static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm, + ktime_t now) +{ + struct k_itimer *ptr = container_of(alarm, struct k_itimer, + it.alarm.alarmtimer); + enum alarmtimer_restart result = ALARMTIMER_NORESTART; + unsigned long flags; + int si_private = 0; + + spin_lock_irqsave(&ptr->it_lock, flags); + + ptr->it_active = 0; + if (ptr->it_interval) + si_private = ++ptr->it_requeue_pending; + + if (posix_timer_event(ptr, si_private) && ptr->it_interval) { + /* + * Handle ignored signals and rearm the timer. This will go + * away once we handle ignored signals proper. Ensure that + * small intervals cannot starve the system. + */ + ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true); + ++ptr->it_requeue_pending; + ptr->it_active = 1; + result = ALARMTIMER_RESTART; + } + spin_unlock_irqrestore(&ptr->it_lock, flags); + + return result; +} + +/** + * alarm_timer_rearm - Posix timer callback for rearming timer + * @timr: Pointer to the posixtimer data struct + */ +static void alarm_timer_rearm(struct k_itimer *timr) +{ + struct alarm *alarm = &timr->it.alarm.alarmtimer; + + timr->it_overrun += alarm_forward_now(alarm, timr->it_interval); + alarm_start(alarm, alarm->node.expires); +} + +/** + * alarm_timer_forward - Posix timer callback for forwarding timer + * @timr: Pointer to the posixtimer data struct + * @now: Current time to forward the timer against + */ +static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now) +{ + struct alarm *alarm = &timr->it.alarm.alarmtimer; + + return alarm_forward(alarm, timr->it_interval, now); +} + +/** + * alarm_timer_remaining - Posix timer callback to retrieve remaining time + * @timr: Pointer to the posixtimer data struct + * @now: Current time to calculate against + */ +static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now) +{ + struct alarm *alarm = &timr->it.alarm.alarmtimer; + + return ktime_sub(alarm->node.expires, now); +} + +/** + * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer + * @timr: Pointer to the posixtimer data struct + */ +static int alarm_timer_try_to_cancel(struct k_itimer *timr) +{ + return alarm_try_to_cancel(&timr->it.alarm.alarmtimer); +} + +/** + * alarm_timer_wait_running - Posix timer callback to wait for a timer + * @timr: Pointer to the posixtimer data struct + * + * Called from the core code when timer cancel detected that the callback + * is running. @timr is unlocked and rcu read lock is held to prevent it + * from being freed. + */ +static void alarm_timer_wait_running(struct k_itimer *timr) +{ + hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer); +} + +/** + * alarm_timer_arm - Posix timer callback to arm a timer + * @timr: Pointer to the posixtimer data struct + * @expires: The new expiry time + * @absolute: Expiry value is absolute time + * @sigev_none: Posix timer does not deliver signals + */ +static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires, + bool absolute, bool sigev_none) +{ + struct alarm *alarm = &timr->it.alarm.alarmtimer; + struct alarm_base *base = &alarm_bases[alarm->type]; + + if (!absolute) + expires = ktime_add_safe(expires, base->get_ktime()); + if (sigev_none) + alarm->node.expires = expires; + else + alarm_start(&timr->it.alarm.alarmtimer, expires); +} + +/** + * alarm_clock_getres - posix getres interface + * @which_clock: clockid + * @tp: timespec to fill + * + * Returns the granularity of underlying alarm base clock + */ +static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp) +{ + if (!alarmtimer_get_rtcdev()) + return -EINVAL; + + tp->tv_sec = 0; + tp->tv_nsec = hrtimer_resolution; + return 0; +} + +/** + * alarm_clock_get_timespec - posix clock_get_timespec interface + * @which_clock: clockid + * @tp: timespec to fill. + * + * Provides the underlying alarm base time in a tasks time namespace. + */ +static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp) +{ + struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; + + if (!alarmtimer_get_rtcdev()) + return -EINVAL; + + base->get_timespec(tp); + + return 0; +} + +/** + * alarm_clock_get_ktime - posix clock_get_ktime interface + * @which_clock: clockid + * + * Provides the underlying alarm base time in the root namespace. + */ +static ktime_t alarm_clock_get_ktime(clockid_t which_clock) +{ + struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; + + if (!alarmtimer_get_rtcdev()) + return -EINVAL; + + return base->get_ktime(); +} + +/** + * alarm_timer_create - posix timer_create interface + * @new_timer: k_itimer pointer to manage + * + * Initializes the k_itimer structure. + */ +static int alarm_timer_create(struct k_itimer *new_timer) +{ + enum alarmtimer_type type; + + if (!alarmtimer_get_rtcdev()) + return -EOPNOTSUPP; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + type = clock2alarm(new_timer->it_clock); + alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer); + return 0; +} + +/** + * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep + * @alarm: ptr to alarm that fired + * @now: time at the timer expiration + * + * Wakes up the task that set the alarmtimer + * + * Return: ALARMTIMER_NORESTART + */ +static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm, + ktime_t now) +{ + struct task_struct *task = alarm->data; + + alarm->data = NULL; + if (task) + wake_up_process(task); + return ALARMTIMER_NORESTART; +} + +/** + * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation + * @alarm: ptr to alarmtimer + * @absexp: absolute expiration time + * @type: alarm type (BOOTTIME/REALTIME). + * + * Sets the alarm timer and sleeps until it is fired or interrupted. + */ +static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp, + enum alarmtimer_type type) +{ + struct restart_block *restart; + alarm->data = (void *)current; + do { + set_current_state(TASK_INTERRUPTIBLE); + alarm_start(alarm, absexp); + if (likely(alarm->data)) + schedule(); + + alarm_cancel(alarm); + } while (alarm->data && !signal_pending(current)); + + __set_current_state(TASK_RUNNING); + + destroy_hrtimer_on_stack(&alarm->timer); + + if (!alarm->data) + return 0; + + if (freezing(current)) + alarmtimer_freezerset(absexp, type); + restart = ¤t->restart_block; + if (restart->nanosleep.type != TT_NONE) { + struct timespec64 rmt; + ktime_t rem; + + rem = ktime_sub(absexp, alarm_bases[type].get_ktime()); + + if (rem <= 0) + return 0; + rmt = ktime_to_timespec64(rem); + + return nanosleep_copyout(restart, &rmt); + } + return -ERESTART_RESTARTBLOCK; +} + +static void +alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type, + enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) +{ + hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid, + HRTIMER_MODE_ABS); + __alarm_init(alarm, type, function); +} + +/** + * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep + * @restart: ptr to restart block + * + * Handles restarted clock_nanosleep calls + */ +static long __sched alarm_timer_nsleep_restart(struct restart_block *restart) +{ + enum alarmtimer_type type = restart->nanosleep.clockid; + ktime_t exp = restart->nanosleep.expires; + struct alarm alarm; + + alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup); + + return alarmtimer_do_nsleep(&alarm, exp, type); +} + +/** + * alarm_timer_nsleep - alarmtimer nanosleep + * @which_clock: clockid + * @flags: determines abstime or relative + * @tsreq: requested sleep time (abs or rel) + * + * Handles clock_nanosleep calls against _ALARM clockids + */ +static int alarm_timer_nsleep(const clockid_t which_clock, int flags, + const struct timespec64 *tsreq) +{ + enum alarmtimer_type type = clock2alarm(which_clock); + struct restart_block *restart = ¤t->restart_block; + struct alarm alarm; + ktime_t exp; + int ret; + + if (!alarmtimer_get_rtcdev()) + return -EOPNOTSUPP; + + if (flags & ~TIMER_ABSTIME) + return -EINVAL; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup); + + exp = timespec64_to_ktime(*tsreq); + /* Convert (if necessary) to absolute time */ + if (flags != TIMER_ABSTIME) { + ktime_t now = alarm_bases[type].get_ktime(); + + exp = ktime_add_safe(now, exp); + } else { + exp = timens_ktime_to_host(which_clock, exp); + } + + ret = alarmtimer_do_nsleep(&alarm, exp, type); + if (ret != -ERESTART_RESTARTBLOCK) + return ret; + + /* abs timers don't set remaining time or restart */ + if (flags == TIMER_ABSTIME) + return -ERESTARTNOHAND; + + restart->nanosleep.clockid = type; + restart->nanosleep.expires = exp; + set_restart_fn(restart, alarm_timer_nsleep_restart); + return ret; +} + +const struct k_clock alarm_clock = { + .clock_getres = alarm_clock_getres, + .clock_get_ktime = alarm_clock_get_ktime, + .clock_get_timespec = alarm_clock_get_timespec, + .timer_create = alarm_timer_create, + .timer_set = common_timer_set, + .timer_del = common_timer_del, + .timer_get = common_timer_get, + .timer_arm = alarm_timer_arm, + .timer_rearm = alarm_timer_rearm, + .timer_forward = alarm_timer_forward, + .timer_remaining = alarm_timer_remaining, + .timer_try_to_cancel = alarm_timer_try_to_cancel, + .timer_wait_running = alarm_timer_wait_running, + .nsleep = alarm_timer_nsleep, +}; +#endif /* CONFIG_POSIX_TIMERS */ + + +/* Suspend hook structures */ +static const struct dev_pm_ops alarmtimer_pm_ops = { + .suspend = alarmtimer_suspend, + .resume = alarmtimer_resume, +}; + +static struct platform_driver alarmtimer_driver = { + .driver = { + .name = "alarmtimer", + .pm = &alarmtimer_pm_ops, + } +}; + +static void get_boottime_timespec(struct timespec64 *tp) +{ + ktime_get_boottime_ts64(tp); + timens_add_boottime(tp); +} + +/** + * alarmtimer_init - Initialize alarm timer code + * + * This function initializes the alarm bases and registers + * the posix clock ids. + */ +static int __init alarmtimer_init(void) +{ + int error; + int i; + + alarmtimer_rtc_timer_init(); + + /* Initialize alarm bases */ + alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; + alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real; + alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64; + alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME; + alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime; + alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec; + for (i = 0; i < ALARM_NUMTYPE; i++) { + timerqueue_init_head(&alarm_bases[i].timerqueue); + spin_lock_init(&alarm_bases[i].lock); + } + + error = alarmtimer_rtc_interface_setup(); + if (error) + return error; + + error = platform_driver_register(&alarmtimer_driver); + if (error) + goto out_if; + + return 0; +out_if: + alarmtimer_rtc_interface_remove(); + return error; +} +device_initcall(alarmtimer_init); |