1// SPDX-License-Identifier: GPL-2.0
2/*
3 * hrtimers - High-resolution kernel timers
4 *
5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
7 *
8 * data type definitions, declarations, prototypes
9 *
10 * Started by: Thomas Gleixner and Ingo Molnar
11 */
12#ifndef _LINUX_HRTIMER_H
13#define _LINUX_HRTIMER_H
14
15#include <linux/hrtimer_defs.h>
16#include <linux/hrtimer_types.h>
17#include <linux/init.h>
18#include <linux/list.h>
19#include <linux/percpu-defs.h>
20#include <linux/rbtree.h>
21#include <linux/timer.h>
22
23/*
24 * Mode arguments of xxx_hrtimer functions:
25 *
26 * HRTIMER_MODE_ABS - Time value is absolute
27 * HRTIMER_MODE_REL - Time value is relative to now
28 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
29 * when starting the timer)
30 * HRTIMER_MODE_SOFT - Timer callback function will be executed in
31 * soft irq context
32 * HRTIMER_MODE_HARD - Timer callback function will be executed in
33 * hard irq context even on PREEMPT_RT.
34 */
35enum hrtimer_mode {
36 HRTIMER_MODE_ABS = 0x00,
37 HRTIMER_MODE_REL = 0x01,
38 HRTIMER_MODE_PINNED = 0x02,
39 HRTIMER_MODE_SOFT = 0x04,
40 HRTIMER_MODE_HARD = 0x08,
41
42 HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
43 HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
44
45 HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
46 HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,
47
48 HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
49 HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,
50
51 HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD,
52 HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD,
53
54 HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD,
55 HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD,
56};
57
58/*
59 * Values to track state of the timer
60 *
61 * Possible states:
62 *
63 * 0x00 inactive
64 * 0x01 enqueued into rbtree
65 *
66 * The callback state is not part of the timer->state because clearing it would
67 * mean touching the timer after the callback, this makes it impossible to free
68 * the timer from the callback function.
69 *
70 * Therefore we track the callback state in:
71 *
72 * timer->base->cpu_base->running == timer
73 *
74 * On SMP it is possible to have a "callback function running and enqueued"
75 * status. It happens for example when a posix timer expired and the callback
76 * queued a signal. Between dropping the lock which protects the posix timer
77 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
78 * signal and rearm the timer.
79 *
80 * All state transitions are protected by cpu_base->lock.
81 */
82#define HRTIMER_STATE_INACTIVE 0x00
83#define HRTIMER_STATE_ENQUEUED 0x01
84
85/**
86 * struct hrtimer_sleeper - simple sleeper structure
87 * @timer: embedded timer structure
88 * @task: task to wake up
89 *
90 * task is set to NULL, when the timer expires.
91 */
92struct hrtimer_sleeper {
93 struct hrtimer timer;
94 struct task_struct *task;
95};
96
97static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
98{
99 timer->node.expires = time;
100 timer->_softexpires = time;
101}
102
103static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
104{
105 timer->_softexpires = time;
106 timer->node.expires = ktime_add_safe(lhs: time, rhs: delta);
107}
108
109static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
110{
111 timer->_softexpires = time;
112 timer->node.expires = ktime_add_safe(lhs: time, rhs: ns_to_ktime(ns: delta));
113}
114
115static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
116{
117 timer->node.expires = tv64;
118 timer->_softexpires = tv64;
119}
120
121static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
122{
123 timer->node.expires = ktime_add_safe(lhs: timer->node.expires, rhs: time);
124 timer->_softexpires = ktime_add_safe(lhs: timer->_softexpires, rhs: time);
125}
126
127static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
128{
129 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
130 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
131}
132
133static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
134{
135 return timer->node.expires;
136}
137
138static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
139{
140 return timer->_softexpires;
141}
142
143static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
144{
145 return timer->node.expires;
146}
147static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
148{
149 return timer->_softexpires;
150}
151
152static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
153{
154 return ktime_to_ns(kt: timer->node.expires);
155}
156
157static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
158{
159 return ktime_sub(timer->node.expires, timer->base->get_time());
160}
161
162static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
163{
164 return timer->base->get_time();
165}
166
167static inline int hrtimer_is_hres_active(struct hrtimer *timer)
168{
169 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
170 timer->base->cpu_base->hres_active : 0;
171}
172
173#ifdef CONFIG_HIGH_RES_TIMERS
174struct clock_event_device;
175
176extern void hrtimer_interrupt(struct clock_event_device *dev);
177
178extern unsigned int hrtimer_resolution;
179
180#else
181
182#define hrtimer_resolution (unsigned int)LOW_RES_NSEC
183
184#endif
185
186static inline ktime_t
187__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
188{
189 ktime_t rem = ktime_sub(timer->node.expires, now);
190
191 /*
192 * Adjust relative timers for the extra we added in
193 * hrtimer_start_range_ns() to prevent short timeouts.
194 */
195 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
196 rem -= hrtimer_resolution;
197 return rem;
198}
199
200static inline ktime_t
201hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
202{
203 return __hrtimer_expires_remaining_adjusted(timer,
204 now: timer->base->get_time());
205}
206
207#ifdef CONFIG_TIMERFD
208extern void timerfd_clock_was_set(void);
209extern void timerfd_resume(void);
210#else
211static inline void timerfd_clock_was_set(void) { }
212static inline void timerfd_resume(void) { }
213#endif
214
215DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
216
217#ifdef CONFIG_PREEMPT_RT
218void hrtimer_cancel_wait_running(const struct hrtimer *timer);
219#else
220static inline void hrtimer_cancel_wait_running(struct hrtimer *timer)
221{
222 cpu_relax();
223}
224#endif
225
226static inline enum hrtimer_restart hrtimer_dummy_timeout(struct hrtimer *unused)
227{
228 return HRTIMER_NORESTART;
229}
230
231/* Exported timer functions: */
232
233/* Initialize timers: */
234extern void hrtimer_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *),
235 clockid_t clock_id, enum hrtimer_mode mode);
236extern void hrtimer_setup_on_stack(struct hrtimer *timer,
237 enum hrtimer_restart (*function)(struct hrtimer *),
238 clockid_t clock_id, enum hrtimer_mode mode);
239extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id,
240 enum hrtimer_mode mode);
241
242#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
243extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
244#else
245static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
246#endif
247
248/* Basic timer operations: */
249extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
250 u64 range_ns, const enum hrtimer_mode mode);
251
252/**
253 * hrtimer_start - (re)start an hrtimer
254 * @timer: the timer to be added
255 * @tim: expiry time
256 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
257 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
258 * softirq based mode is considered for debug purpose only!
259 */
260static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
261 const enum hrtimer_mode mode)
262{
263 hrtimer_start_range_ns(timer, tim, range_ns: 0, mode);
264}
265
266extern int hrtimer_cancel(struct hrtimer *timer);
267extern int hrtimer_try_to_cancel(struct hrtimer *timer);
268
269static inline void hrtimer_start_expires(struct hrtimer *timer,
270 enum hrtimer_mode mode)
271{
272 u64 delta;
273 ktime_t soft, hard;
274 soft = hrtimer_get_softexpires(timer);
275 hard = hrtimer_get_expires(timer);
276 delta = ktime_to_ns(ktime_sub(hard, soft));
277 hrtimer_start_range_ns(timer, tim: soft, range_ns: delta, mode);
278}
279
280void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
281 enum hrtimer_mode mode);
282
283static inline void hrtimer_restart(struct hrtimer *timer)
284{
285 hrtimer_start_expires(timer, mode: HRTIMER_MODE_ABS);
286}
287
288/* Query timers: */
289extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
290
291/**
292 * hrtimer_get_remaining - get remaining time for the timer
293 * @timer: the timer to read
294 */
295static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
296{
297 return __hrtimer_get_remaining(timer, adjust: false);
298}
299
300extern u64 hrtimer_get_next_event(void);
301extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
302
303extern bool hrtimer_active(const struct hrtimer *timer);
304
305/**
306 * hrtimer_is_queued - check, whether the timer is on one of the queues
307 * @timer: Timer to check
308 *
309 * Returns: True if the timer is queued, false otherwise
310 *
311 * The function can be used lockless, but it gives only a current snapshot.
312 */
313static inline bool hrtimer_is_queued(struct hrtimer *timer)
314{
315 /* The READ_ONCE pairs with the update functions of timer->state */
316 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
317}
318
319/*
320 * Helper function to check, whether the timer is running the callback
321 * function
322 */
323static inline int hrtimer_callback_running(struct hrtimer *timer)
324{
325 return timer->base->running == timer;
326}
327
328/**
329 * hrtimer_update_function - Update the timer's callback function
330 * @timer: Timer to update
331 * @function: New callback function
332 *
333 * Only safe to call if the timer is not enqueued. Can be called in the callback function if the
334 * timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED).
335 */
336static inline void hrtimer_update_function(struct hrtimer *timer,
337 enum hrtimer_restart (*function)(struct hrtimer *))
338{
339#ifdef CONFIG_PROVE_LOCKING
340 guard(raw_spinlock_irqsave)(l: &timer->base->cpu_base->lock);
341
342 if (WARN_ON_ONCE(hrtimer_is_queued(timer)))
343 return;
344
345 if (WARN_ON_ONCE(!function))
346 return;
347#endif
348 ACCESS_PRIVATE(timer, function) = function;
349}
350
351/* Forward a hrtimer so it expires after now: */
352extern u64
353hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
354
355/**
356 * hrtimer_forward_now() - forward the timer expiry so it expires after now
357 * @timer: hrtimer to forward
358 * @interval: the interval to forward
359 *
360 * It is a variant of hrtimer_forward(). The timer will expire after the current
361 * time of the hrtimer clock base. See hrtimer_forward() for details.
362 */
363static inline u64 hrtimer_forward_now(struct hrtimer *timer,
364 ktime_t interval)
365{
366 return hrtimer_forward(timer, now: timer->base->get_time(), interval);
367}
368
369/* Precise sleep: */
370
371extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
372extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
373 const clockid_t clockid);
374
375extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
376 const enum hrtimer_mode mode);
377extern int schedule_hrtimeout_range_clock(ktime_t *expires,
378 u64 delta,
379 const enum hrtimer_mode mode,
380 clockid_t clock_id);
381extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
382
383/* Soft interrupt function to run the hrtimer queues: */
384extern void hrtimer_run_queues(void);
385
386/* Bootup initialization: */
387extern void __init hrtimers_init(void);
388
389/* Show pending timers: */
390extern void sysrq_timer_list_show(void);
391
392int hrtimers_prepare_cpu(unsigned int cpu);
393int hrtimers_cpu_starting(unsigned int cpu);
394#ifdef CONFIG_HOTPLUG_CPU
395int hrtimers_cpu_dying(unsigned int cpu);
396#else
397#define hrtimers_cpu_dying NULL
398#endif
399
400#endif
401

source code of linux/include/linux/hrtimer.h

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