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Diffstat (limited to 'include/linux/hrtimer.h')
| -rw-r--r-- | include/linux/hrtimer.h | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h new file mode 100644 index 000000000..f2044d5a6 --- /dev/null +++ b/include/linux/hrtimer.h @@ -0,0 +1,539 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * hrtimers - High-resolution kernel timers + * + * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> + * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar + * + * data type definitions, declarations, prototypes + * + * Started by: Thomas Gleixner and Ingo Molnar + */ +#ifndef _LINUX_HRTIMER_H +#define _LINUX_HRTIMER_H + +#include <linux/hrtimer_defs.h> +#include <linux/rbtree.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/percpu.h> +#include <linux/seqlock.h> +#include <linux/timer.h> +#include <linux/timerqueue.h> + +struct hrtimer_clock_base; +struct hrtimer_cpu_base; + +/* + * Mode arguments of xxx_hrtimer functions: + * + * HRTIMER_MODE_ABS - Time value is absolute + * HRTIMER_MODE_REL - Time value is relative to now + * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered + * when starting the timer) + * HRTIMER_MODE_SOFT - Timer callback function will be executed in + * soft irq context + * HRTIMER_MODE_HARD - Timer callback function will be executed in + * hard irq context even on PREEMPT_RT. + */ +enum hrtimer_mode { + HRTIMER_MODE_ABS = 0x00, + HRTIMER_MODE_REL = 0x01, + HRTIMER_MODE_PINNED = 0x02, + HRTIMER_MODE_SOFT = 0x04, + HRTIMER_MODE_HARD = 0x08, + + HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED, + HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED, + + HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT, + HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT, + + HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT, + HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT, + + HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD, + HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD, + + HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD, + HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD, +}; + +/* + * Return values for the callback function + */ +enum hrtimer_restart { + HRTIMER_NORESTART, /* Timer is not restarted */ + HRTIMER_RESTART, /* Timer must be restarted */ +}; + +/* + * Values to track state of the timer + * + * Possible states: + * + * 0x00 inactive + * 0x01 enqueued into rbtree + * + * The callback state is not part of the timer->state because clearing it would + * mean touching the timer after the callback, this makes it impossible to free + * the timer from the callback function. + * + * Therefore we track the callback state in: + * + * timer->base->cpu_base->running == timer + * + * On SMP it is possible to have a "callback function running and enqueued" + * status. It happens for example when a posix timer expired and the callback + * queued a signal. Between dropping the lock which protects the posix timer + * and reacquiring the base lock of the hrtimer, another CPU can deliver the + * signal and rearm the timer. + * + * All state transitions are protected by cpu_base->lock. + */ +#define HRTIMER_STATE_INACTIVE 0x00 +#define HRTIMER_STATE_ENQUEUED 0x01 + +/** + * struct hrtimer - the basic hrtimer structure + * @node: timerqueue node, which also manages node.expires, + * the absolute expiry time in the hrtimers internal + * representation. The time is related to the clock on + * which the timer is based. Is setup by adding + * slack to the _softexpires value. For non range timers + * identical to _softexpires. + * @_softexpires: the absolute earliest expiry time of the hrtimer. + * The time which was given as expiry time when the timer + * was armed. + * @function: timer expiry callback function + * @base: pointer to the timer base (per cpu and per clock) + * @state: state information (See bit values above) + * @is_rel: Set if the timer was armed relative + * @is_soft: Set if hrtimer will be expired in soft interrupt context. + * @is_hard: Set if hrtimer will be expired in hard interrupt context + * even on RT. + * + * The hrtimer structure must be initialized by hrtimer_init() + */ +struct hrtimer { + struct timerqueue_node node; + ktime_t _softexpires; + enum hrtimer_restart (*function)(struct hrtimer *); + struct hrtimer_clock_base *base; + u8 state; + u8 is_rel; + u8 is_soft; + u8 is_hard; +}; + +/** + * struct hrtimer_sleeper - simple sleeper structure + * @timer: embedded timer structure + * @task: task to wake up + * + * task is set to NULL, when the timer expires. + */ +struct hrtimer_sleeper { + struct hrtimer timer; + struct task_struct *task; +}; + +#ifdef CONFIG_64BIT +# define __hrtimer_clock_base_align ____cacheline_aligned +#else +# define __hrtimer_clock_base_align +#endif + +/** + * struct hrtimer_clock_base - the timer base for a specific clock + * @cpu_base: per cpu clock base + * @index: clock type index for per_cpu support when moving a + * timer to a base on another cpu. + * @clockid: clock id for per_cpu support + * @seq: seqcount around __run_hrtimer + * @running: pointer to the currently running hrtimer + * @active: red black tree root node for the active timers + * @get_time: function to retrieve the current time of the clock + * @offset: offset of this clock to the monotonic base + */ +struct hrtimer_clock_base { + struct hrtimer_cpu_base *cpu_base; + unsigned int index; + clockid_t clockid; + seqcount_raw_spinlock_t seq; + struct hrtimer *running; + struct timerqueue_head active; + ktime_t (*get_time)(void); + ktime_t offset; +} __hrtimer_clock_base_align; + +enum hrtimer_base_type { + HRTIMER_BASE_MONOTONIC, + HRTIMER_BASE_REALTIME, + HRTIMER_BASE_BOOTTIME, + HRTIMER_BASE_TAI, + HRTIMER_BASE_MONOTONIC_SOFT, + HRTIMER_BASE_REALTIME_SOFT, + HRTIMER_BASE_BOOTTIME_SOFT, + HRTIMER_BASE_TAI_SOFT, + HRTIMER_MAX_CLOCK_BASES, +}; + +/** + * struct hrtimer_cpu_base - the per cpu clock bases + * @lock: lock protecting the base and associated clock bases + * and timers + * @cpu: cpu number + * @active_bases: Bitfield to mark bases with active timers + * @clock_was_set_seq: Sequence counter of clock was set events + * @hres_active: State of high resolution mode + * @in_hrtirq: hrtimer_interrupt() is currently executing + * @hang_detected: The last hrtimer interrupt detected a hang + * @softirq_activated: displays, if the softirq is raised - update of softirq + * related settings is not required then. + * @nr_events: Total number of hrtimer interrupt events + * @nr_retries: Total number of hrtimer interrupt retries + * @nr_hangs: Total number of hrtimer interrupt hangs + * @max_hang_time: Maximum time spent in hrtimer_interrupt + * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are + * expired + * @timer_waiters: A hrtimer_cancel() invocation waits for the timer + * callback to finish. + * @expires_next: absolute time of the next event, is required for remote + * hrtimer enqueue; it is the total first expiry time (hard + * and soft hrtimer are taken into account) + * @next_timer: Pointer to the first expiring timer + * @softirq_expires_next: Time to check, if soft queues needs also to be expired + * @softirq_next_timer: Pointer to the first expiring softirq based timer + * @clock_base: array of clock bases for this cpu + * + * Note: next_timer is just an optimization for __remove_hrtimer(). + * Do not dereference the pointer because it is not reliable on + * cross cpu removals. + */ +struct hrtimer_cpu_base { + raw_spinlock_t lock; + unsigned int cpu; + unsigned int active_bases; + unsigned int clock_was_set_seq; + unsigned int hres_active : 1, + in_hrtirq : 1, + hang_detected : 1, + softirq_activated : 1; +#ifdef CONFIG_HIGH_RES_TIMERS + unsigned int nr_events; + unsigned short nr_retries; + unsigned short nr_hangs; + unsigned int max_hang_time; +#endif +#ifdef CONFIG_PREEMPT_RT + spinlock_t softirq_expiry_lock; + atomic_t timer_waiters; +#endif + ktime_t expires_next; + struct hrtimer *next_timer; + ktime_t softirq_expires_next; + struct hrtimer *softirq_next_timer; + struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; +} ____cacheline_aligned; + +static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) +{ + timer->node.expires = time; + timer->_softexpires = time; +} + +static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) +{ + timer->_softexpires = time; + timer->node.expires = ktime_add_safe(time, delta); +} + +static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta) +{ + timer->_softexpires = time; + timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); +} + +static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) +{ + timer->node.expires = tv64; + timer->_softexpires = tv64; +} + +static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) +{ + timer->node.expires = ktime_add_safe(timer->node.expires, time); + timer->_softexpires = ktime_add_safe(timer->_softexpires, time); +} + +static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) +{ + timer->node.expires = ktime_add_ns(timer->node.expires, ns); + timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); +} + +static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) +{ + return timer->node.expires; +} + +static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) +{ + return timer->_softexpires; +} + +static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) +{ + return timer->node.expires; +} +static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) +{ + return timer->_softexpires; +} + +static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) +{ + return ktime_to_ns(timer->node.expires); +} + +static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) +{ + return ktime_sub(timer->node.expires, timer->base->get_time()); +} + +static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) +{ + return timer->base->get_time(); +} + +static inline int hrtimer_is_hres_active(struct hrtimer *timer) +{ + return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ? + timer->base->cpu_base->hres_active : 0; +} + +#ifdef CONFIG_HIGH_RES_TIMERS +struct clock_event_device; + +extern void hrtimer_interrupt(struct clock_event_device *dev); + +extern unsigned int hrtimer_resolution; + +#else + +#define hrtimer_resolution (unsigned int)LOW_RES_NSEC + +#endif + +static inline ktime_t +__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now) +{ + ktime_t rem = ktime_sub(timer->node.expires, now); + + /* + * Adjust relative timers for the extra we added in + * hrtimer_start_range_ns() to prevent short timeouts. + */ + if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel) + rem -= hrtimer_resolution; + return rem; +} + +static inline ktime_t +hrtimer_expires_remaining_adjusted(const struct hrtimer *timer) +{ + return __hrtimer_expires_remaining_adjusted(timer, + timer->base->get_time()); +} + +#ifdef CONFIG_TIMERFD +extern void timerfd_clock_was_set(void); +extern void timerfd_resume(void); +#else +static inline void timerfd_clock_was_set(void) { } +static inline void timerfd_resume(void) { } +#endif + +DECLARE_PER_CPU(struct tick_device, tick_cpu_device); + +#ifdef CONFIG_PREEMPT_RT +void hrtimer_cancel_wait_running(const struct hrtimer *timer); +#else +static inline void hrtimer_cancel_wait_running(struct hrtimer *timer) +{ + cpu_relax(); +} +#endif + +/* Exported timer functions: */ + +/* Initialize timers: */ +extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, + enum hrtimer_mode mode); +extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id, + enum hrtimer_mode mode); + +#ifdef CONFIG_DEBUG_OBJECTS_TIMERS +extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, + enum hrtimer_mode mode); +extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, + clockid_t clock_id, + enum hrtimer_mode mode); + +extern void destroy_hrtimer_on_stack(struct hrtimer *timer); +#else +static inline void hrtimer_init_on_stack(struct hrtimer *timer, + clockid_t which_clock, + enum hrtimer_mode mode) +{ + hrtimer_init(timer, which_clock, mode); +} + +static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, + clockid_t clock_id, + enum hrtimer_mode mode) +{ + hrtimer_init_sleeper(sl, clock_id, mode); +} + +static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } +#endif + +/* Basic timer operations: */ +extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + u64 range_ns, const enum hrtimer_mode mode); + +/** + * hrtimer_start - (re)start an hrtimer + * @timer: the timer to be added + * @tim: expiry time + * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or + * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED); + * softirq based mode is considered for debug purpose only! + */ +static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim, + const enum hrtimer_mode mode) +{ + hrtimer_start_range_ns(timer, tim, 0, mode); +} + +extern int hrtimer_cancel(struct hrtimer *timer); +extern int hrtimer_try_to_cancel(struct hrtimer *timer); + +static inline void hrtimer_start_expires(struct hrtimer *timer, + enum hrtimer_mode mode) +{ + u64 delta; + ktime_t soft, hard; + soft = hrtimer_get_softexpires(timer); + hard = hrtimer_get_expires(timer); + delta = ktime_to_ns(ktime_sub(hard, soft)); + hrtimer_start_range_ns(timer, soft, delta, mode); +} + +void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl, + enum hrtimer_mode mode); + +static inline void hrtimer_restart(struct hrtimer *timer) +{ + hrtimer_start_expires(timer, HRTIMER_MODE_ABS); +} + +/* Query timers: */ +extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust); + +/** + * hrtimer_get_remaining - get remaining time for the timer + * @timer: the timer to read + */ +static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) +{ + return __hrtimer_get_remaining(timer, false); +} + +extern u64 hrtimer_get_next_event(void); +extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); + +extern bool hrtimer_active(const struct hrtimer *timer); + +/** + * hrtimer_is_queued - check, whether the timer is on one of the queues + * @timer: Timer to check + * + * Returns: True if the timer is queued, false otherwise + * + * The function can be used lockless, but it gives only a current snapshot. + */ +static inline bool hrtimer_is_queued(struct hrtimer *timer) +{ + /* The READ_ONCE pairs with the update functions of timer->state */ + return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED); +} + +/* + * Helper function to check, whether the timer is running the callback + * function + */ +static inline int hrtimer_callback_running(struct hrtimer *timer) +{ + return timer->base->running == timer; +} + +/* Forward a hrtimer so it expires after now: */ +extern u64 +hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); + +/** + * hrtimer_forward_now - forward the timer expiry so it expires after now + * @timer: hrtimer to forward + * @interval: the interval to forward + * + * Forward the timer expiry so it will expire after the current time + * of the hrtimer clock base. Returns the number of overruns. + * + * Can be safely called from the callback function of @timer. If + * called from other contexts @timer must neither be enqueued nor + * running the callback and the caller needs to take care of + * serialization. + * + * Note: This only updates the timer expiry value and does not requeue + * the timer. + */ +static inline u64 hrtimer_forward_now(struct hrtimer *timer, + ktime_t interval) +{ + return hrtimer_forward(timer, timer->base->get_time(), interval); +} + +/* Precise sleep: */ + +extern int nanosleep_copyout(struct restart_block *, struct timespec64 *); +extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode, + const clockid_t clockid); + +extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta, + const enum hrtimer_mode mode); +extern int schedule_hrtimeout_range_clock(ktime_t *expires, + u64 delta, + const enum hrtimer_mode mode, + clockid_t clock_id); +extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); + +/* Soft interrupt function to run the hrtimer queues: */ +extern void hrtimer_run_queues(void); + +/* Bootup initialization: */ +extern void __init hrtimers_init(void); + +/* Show pending timers: */ +extern void sysrq_timer_list_show(void); + +int hrtimers_prepare_cpu(unsigned int cpu); +#ifdef CONFIG_HOTPLUG_CPU +int hrtimers_cpu_dying(unsigned int cpu); +#else +#define hrtimers_cpu_dying NULL +#endif + +#endif |