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products/sources/formale Sprachen/C/Linux/include/linux/ (Open Source Betriebssystem Version 6.17.9^©) Datei vom 24.10.2025 mit Größe 11 kB

Quelle hrtimer.h Sprache: C

// 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/hrtimer_types.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/percpu-defs.h>
#include <linux/rbtree.h>
#include <linux/timer.h>

/*
* 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,
};

/*
* 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_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;
};

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

static inline enum hrtimer_restart hrtimer_dummy_timeout(struct hrtimer *unused)
{
return HRTIMER_NORESTART;
}

/* Exported timer functions: */

/* Initialize timers: */
extern void hrtimer_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *),
     clockid_t clock_id, enum hrtimer_mode mode);
extern void hrtimer_setup_on_stack(struct hrtimer *timer,
       enum hrtimer_restart (*function)(struct hrtimer *),
       clockid_t clock_id, enum hrtimer_mode mode);
extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id,
        enum hrtimer_mode mode);

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
#else
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;
}

/**
* hrtimer_update_function - Update the timer's callback function
* @timer: Timer to update
* @function: New callback function
*
* Only safe to call if the timer is not enqueued. Can be called in the callback function if the
* timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED).
*/
static inline void hrtimer_update_function(struct hrtimer *timer,
        enum hrtimer_restart (*function)(struct hrtimer *))
{
#ifdef CONFIG_PROVE_LOCKING
guard(raw_spinlock_irqsave)(&timer->base->cpu_base->lock);

if (WARN_ON_ONCE(hrtimer_is_queued(timer)))
  return;

if (WARN_ON_ONCE(!function))
  return;
#endif
ACCESS_PRIVATE(timer, function) = function;
}

/* 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
*
* It is a variant of hrtimer_forward(). The timer will expire after the current
* time of the hrtimer clock base. See hrtimer_forward() for details.
*/
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);
int hrtimers_cpu_starting(unsigned int cpu);
#ifdef CONFIG_HOTPLUG_CPU
int hrtimers_cpu_dying(unsigned int cpu);
#else
#define hrtimers_cpu_dying NULL
#endif

#endif

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