1 // SPDX-License-Identifier: GPL-2.0
3 * hrtimers - High-resolution kernel timers
5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
8 * data type definitions, declarations, prototypes
10 * Started by: Thomas Gleixner and Ingo Molnar
12 #ifndef _LINUX_HRTIMER_H
13 #define _LINUX_HRTIMER_H
15 #include <linux/hrtimer_defs.h>
16 #include <linux/rbtree.h>
17 #include <linux/init.h>
18 #include <linux/list.h>
19 #include <linux/percpu.h>
20 #include <linux/timer.h>
21 #include <linux/timerqueue.h>
23 struct hrtimer_clock_base;
24 struct hrtimer_cpu_base;
27 * Mode arguments of xxx_hrtimer functions:
29 * HRTIMER_MODE_ABS - Time value is absolute
30 * HRTIMER_MODE_REL - Time value is relative to now
31 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
32 * when starting the timer)
33 * HRTIMER_MODE_SOFT - Timer callback function will be executed in
37 HRTIMER_MODE_ABS = 0x00,
38 HRTIMER_MODE_REL = 0x01,
39 HRTIMER_MODE_PINNED = 0x02,
40 HRTIMER_MODE_SOFT = 0x04,
41 HRTIMER_MODE_HARD = 0x08,
43 HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
44 HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
46 HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
47 HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,
49 HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
50 HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,
52 HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD,
53 HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD,
55 HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD,
56 HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD,
60 * Return values for the callback function
62 enum hrtimer_restart {
63 HRTIMER_NORESTART, /* Timer is not restarted */
64 HRTIMER_RESTART, /* Timer must be restarted */
68 * Values to track state of the timer
73 * 0x01 enqueued into rbtree
75 * The callback state is not part of the timer->state because clearing it would
76 * mean touching the timer after the callback, this makes it impossible to free
77 * the timer from the callback function.
79 * Therefore we track the callback state in:
81 * timer->base->cpu_base->running == timer
83 * On SMP it is possible to have a "callback function running and enqueued"
84 * status. It happens for example when a posix timer expired and the callback
85 * queued a signal. Between dropping the lock which protects the posix timer
86 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
87 * signal and rearm the timer.
89 * All state transitions are protected by cpu_base->lock.
91 #define HRTIMER_STATE_INACTIVE 0x00
92 #define HRTIMER_STATE_ENQUEUED 0x01
95 * struct hrtimer - the basic hrtimer structure
96 * @node: timerqueue node, which also manages node.expires,
97 * the absolute expiry time in the hrtimers internal
98 * representation. The time is related to the clock on
99 * which the timer is based. Is setup by adding
100 * slack to the _softexpires value. For non range timers
101 * identical to _softexpires.
102 * @_softexpires: the absolute earliest expiry time of the hrtimer.
103 * The time which was given as expiry time when the timer
105 * @function: timer expiry callback function
106 * @base: pointer to the timer base (per cpu and per clock)
107 * @state: state information (See bit values above)
108 * @is_rel: Set if the timer was armed relative
109 * @is_soft: Set if hrtimer will be expired in soft interrupt context.
111 * The hrtimer structure must be initialized by hrtimer_init()
114 struct timerqueue_node node;
115 ktime_t _softexpires;
116 enum hrtimer_restart (*function)(struct hrtimer *);
117 struct hrtimer_clock_base *base;
124 * struct hrtimer_sleeper - simple sleeper structure
125 * @timer: embedded timer structure
126 * @task: task to wake up
128 * task is set to NULL, when the timer expires.
130 struct hrtimer_sleeper {
131 struct hrtimer timer;
132 struct task_struct *task;
136 # define __hrtimer_clock_base_align ____cacheline_aligned
138 # define __hrtimer_clock_base_align
142 * struct hrtimer_clock_base - the timer base for a specific clock
143 * @cpu_base: per cpu clock base
144 * @index: clock type index for per_cpu support when moving a
145 * timer to a base on another cpu.
146 * @clockid: clock id for per_cpu support
147 * @seq: seqcount around __run_hrtimer
148 * @running: pointer to the currently running hrtimer
149 * @active: red black tree root node for the active timers
150 * @get_time: function to retrieve the current time of the clock
151 * @offset: offset of this clock to the monotonic base
153 struct hrtimer_clock_base {
154 struct hrtimer_cpu_base *cpu_base;
158 struct hrtimer *running;
159 struct timerqueue_head active;
160 ktime_t (*get_time)(void);
162 } __hrtimer_clock_base_align;
164 enum hrtimer_base_type {
165 HRTIMER_BASE_MONOTONIC,
166 HRTIMER_BASE_REALTIME,
167 HRTIMER_BASE_BOOTTIME,
169 HRTIMER_BASE_MONOTONIC_SOFT,
170 HRTIMER_BASE_REALTIME_SOFT,
171 HRTIMER_BASE_BOOTTIME_SOFT,
172 HRTIMER_BASE_TAI_SOFT,
173 HRTIMER_MAX_CLOCK_BASES,
177 * struct hrtimer_cpu_base - the per cpu clock bases
178 * @lock: lock protecting the base and associated clock bases
181 * @active_bases: Bitfield to mark bases with active timers
182 * @clock_was_set_seq: Sequence counter of clock was set events
183 * @hres_active: State of high resolution mode
184 * @in_hrtirq: hrtimer_interrupt() is currently executing
185 * @hang_detected: The last hrtimer interrupt detected a hang
186 * @softirq_activated: displays, if the softirq is raised - update of softirq
187 * related settings is not required then.
188 * @nr_events: Total number of hrtimer interrupt events
189 * @nr_retries: Total number of hrtimer interrupt retries
190 * @nr_hangs: Total number of hrtimer interrupt hangs
191 * @max_hang_time: Maximum time spent in hrtimer_interrupt
192 * @expires_next: absolute time of the next event, is required for remote
193 * hrtimer enqueue; it is the total first expiry time (hard
194 * and soft hrtimer are taken into account)
195 * @next_timer: Pointer to the first expiring timer
196 * @softirq_expires_next: Time to check, if soft queues needs also to be expired
197 * @softirq_next_timer: Pointer to the first expiring softirq based timer
198 * @clock_base: array of clock bases for this cpu
200 * Note: next_timer is just an optimization for __remove_hrtimer().
201 * Do not dereference the pointer because it is not reliable on
202 * cross cpu removals.
204 struct hrtimer_cpu_base {
207 unsigned int active_bases;
208 unsigned int clock_was_set_seq;
209 unsigned int hres_active : 1,
212 softirq_activated : 1;
213 #ifdef CONFIG_HIGH_RES_TIMERS
214 unsigned int nr_events;
215 unsigned short nr_retries;
216 unsigned short nr_hangs;
217 unsigned int max_hang_time;
219 ktime_t expires_next;
220 struct hrtimer *next_timer;
221 ktime_t softirq_expires_next;
222 struct hrtimer *softirq_next_timer;
223 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
224 } ____cacheline_aligned;
226 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
228 timer->node.expires = time;
229 timer->_softexpires = time;
232 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
234 timer->_softexpires = time;
235 timer->node.expires = ktime_add_safe(time, delta);
238 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
240 timer->_softexpires = time;
241 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
244 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
246 timer->node.expires = tv64;
247 timer->_softexpires = tv64;
250 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
252 timer->node.expires = ktime_add_safe(timer->node.expires, time);
253 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
256 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
258 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
259 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
262 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
264 return timer->node.expires;
267 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
269 return timer->_softexpires;
272 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
274 return timer->node.expires;
276 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
278 return timer->_softexpires;
281 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
283 return ktime_to_ns(timer->node.expires);
286 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
288 return ktime_sub(timer->node.expires, timer->base->get_time());
291 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
293 return timer->base->get_time();
296 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
298 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
299 timer->base->cpu_base->hres_active : 0;
302 #ifdef CONFIG_HIGH_RES_TIMERS
303 struct clock_event_device;
305 extern void hrtimer_interrupt(struct clock_event_device *dev);
307 extern void clock_was_set_delayed(void);
309 extern unsigned int hrtimer_resolution;
313 #define hrtimer_resolution (unsigned int)LOW_RES_NSEC
315 static inline void clock_was_set_delayed(void) { }
319 static inline ktime_t
320 __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
322 ktime_t rem = ktime_sub(timer->node.expires, now);
325 * Adjust relative timers for the extra we added in
326 * hrtimer_start_range_ns() to prevent short timeouts.
328 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
329 rem -= hrtimer_resolution;
333 static inline ktime_t
334 hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
336 return __hrtimer_expires_remaining_adjusted(timer,
337 timer->base->get_time());
340 extern void clock_was_set(void);
341 #ifdef CONFIG_TIMERFD
342 extern void timerfd_clock_was_set(void);
344 static inline void timerfd_clock_was_set(void) { }
346 extern void hrtimers_resume(void);
348 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
351 /* Exported timer functions: */
353 /* Initialize timers: */
354 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
355 enum hrtimer_mode mode);
356 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
357 enum hrtimer_mode mode);
359 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
360 extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
361 enum hrtimer_mode mode);
362 extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
364 enum hrtimer_mode mode);
366 extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
368 static inline void hrtimer_init_on_stack(struct hrtimer *timer,
369 clockid_t which_clock,
370 enum hrtimer_mode mode)
372 hrtimer_init(timer, which_clock, mode);
375 static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
377 enum hrtimer_mode mode)
379 hrtimer_init_sleeper(sl, clock_id, mode);
382 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
385 /* Basic timer operations: */
386 extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
387 u64 range_ns, const enum hrtimer_mode mode);
390 * hrtimer_start - (re)start an hrtimer
391 * @timer: the timer to be added
393 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
394 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
395 * softirq based mode is considered for debug purpose only!
397 static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
398 const enum hrtimer_mode mode)
400 hrtimer_start_range_ns(timer, tim, 0, mode);
403 extern int hrtimer_cancel(struct hrtimer *timer);
404 extern int hrtimer_try_to_cancel(struct hrtimer *timer);
406 static inline void hrtimer_start_expires(struct hrtimer *timer,
407 enum hrtimer_mode mode)
411 soft = hrtimer_get_softexpires(timer);
412 hard = hrtimer_get_expires(timer);
413 delta = ktime_to_ns(ktime_sub(hard, soft));
414 hrtimer_start_range_ns(timer, soft, delta, mode);
417 void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
418 enum hrtimer_mode mode);
420 static inline void hrtimer_restart(struct hrtimer *timer)
422 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
426 extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
428 static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
430 return __hrtimer_get_remaining(timer, false);
433 extern u64 hrtimer_get_next_event(void);
434 extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
436 extern bool hrtimer_active(const struct hrtimer *timer);
439 * Helper function to check, whether the timer is on one of the queues
441 static inline int hrtimer_is_queued(struct hrtimer *timer)
443 return timer->state & HRTIMER_STATE_ENQUEUED;
447 * Helper function to check, whether the timer is running the callback
450 static inline int hrtimer_callback_running(struct hrtimer *timer)
452 return timer->base->running == timer;
455 /* Forward a hrtimer so it expires after now: */
457 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
460 * hrtimer_forward_now - forward the timer expiry so it expires after now
461 * @timer: hrtimer to forward
462 * @interval: the interval to forward
464 * Forward the timer expiry so it will expire after the current time
465 * of the hrtimer clock base. Returns the number of overruns.
467 * Can be safely called from the callback function of @timer. If
468 * called from other contexts @timer must neither be enqueued nor
469 * running the callback and the caller needs to take care of
472 * Note: This only updates the timer expiry value and does not requeue
475 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
478 return hrtimer_forward(timer, timer->base->get_time(), interval);
483 extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
484 extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
485 const enum hrtimer_mode mode,
486 const clockid_t clockid);
488 extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
489 const enum hrtimer_mode mode);
490 extern int schedule_hrtimeout_range_clock(ktime_t *expires,
492 const enum hrtimer_mode mode,
494 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
496 /* Soft interrupt function to run the hrtimer queues: */
497 extern void hrtimer_run_queues(void);
499 /* Bootup initialization: */
500 extern void __init hrtimers_init(void);
502 /* Show pending timers: */
503 extern void sysrq_timer_list_show(void);
505 int hrtimers_prepare_cpu(unsigned int cpu);
506 #ifdef CONFIG_HOTPLUG_CPU
507 int hrtimers_dead_cpu(unsigned int cpu);
509 #define hrtimers_dead_cpu NULL