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
226/* Exported timer functions: */
227
228/* Initialize timers: */
229extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
230 enum hrtimer_mode mode);
231extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
232 enum hrtimer_mode mode);
233
234#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
235extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
236 enum hrtimer_mode mode);
237extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
238 clockid_t clock_id,
239 enum hrtimer_mode mode);
240
241extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
242#else
243static inline void hrtimer_init_on_stack(struct hrtimer *timer,
244 clockid_t which_clock,
245 enum hrtimer_mode mode)
246{
247 hrtimer_init(timer, which_clock, mode);
248}
249
250static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
251 clockid_t clock_id,
252 enum hrtimer_mode mode)
253{
254 hrtimer_init_sleeper(sl, clock_id, mode);
255}
256
257static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
258#endif
259
260/* Basic timer operations: */
261extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
262 u64 range_ns, const enum hrtimer_mode mode);
263
264/**
265 * hrtimer_start - (re)start an hrtimer
266 * @timer: the timer to be added
267 * @tim: expiry time
268 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
269 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
270 * softirq based mode is considered for debug purpose only!
271 */
272static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
273 const enum hrtimer_mode mode)
274{
275 hrtimer_start_range_ns(timer, tim, range_ns: 0, mode);
276}
277
278extern int hrtimer_cancel(struct hrtimer *timer);
279extern int hrtimer_try_to_cancel(struct hrtimer *timer);
280
281static inline void hrtimer_start_expires(struct hrtimer *timer,
282 enum hrtimer_mode mode)
283{
284 u64 delta;
285 ktime_t soft, hard;
286 soft = hrtimer_get_softexpires(timer);
287 hard = hrtimer_get_expires(timer);
288 delta = ktime_to_ns(ktime_sub(hard, soft));
289 hrtimer_start_range_ns(timer, tim: soft, range_ns: delta, mode);
290}
291
292void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
293 enum hrtimer_mode mode);
294
295static inline void hrtimer_restart(struct hrtimer *timer)
296{
297 hrtimer_start_expires(timer, mode: HRTIMER_MODE_ABS);
298}
299
300/* Query timers: */
301extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
302
303/**
304 * hrtimer_get_remaining - get remaining time for the timer
305 * @timer: the timer to read
306 */
307static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
308{
309 return __hrtimer_get_remaining(timer, adjust: false);
310}
311
312extern u64 hrtimer_get_next_event(void);
313extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
314
315extern bool hrtimer_active(const struct hrtimer *timer);
316
317/**
318 * hrtimer_is_queued - check, whether the timer is on one of the queues
319 * @timer: Timer to check
320 *
321 * Returns: True if the timer is queued, false otherwise
322 *
323 * The function can be used lockless, but it gives only a current snapshot.
324 */
325static inline bool hrtimer_is_queued(struct hrtimer *timer)
326{
327 /* The READ_ONCE pairs with the update functions of timer->state */
328 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
329}
330
331/*
332 * Helper function to check, whether the timer is running the callback
333 * function
334 */
335static inline int hrtimer_callback_running(struct hrtimer *timer)
336{
337 return timer->base->running == timer;
338}
339
340/* Forward a hrtimer so it expires after now: */
341extern u64
342hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
343
344/**
345 * hrtimer_forward_now() - forward the timer expiry so it expires after now
346 * @timer: hrtimer to forward
347 * @interval: the interval to forward
348 *
349 * It is a variant of hrtimer_forward(). The timer will expire after the current
350 * time of the hrtimer clock base. See hrtimer_forward() for details.
351 */
352static inline u64 hrtimer_forward_now(struct hrtimer *timer,
353 ktime_t interval)
354{
355 return hrtimer_forward(timer, now: timer->base->get_time(), interval);
356}
357
358/* Precise sleep: */
359
360extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
361extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
362 const clockid_t clockid);
363
364extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
365 const enum hrtimer_mode mode);
366extern int schedule_hrtimeout_range_clock(ktime_t *expires,
367 u64 delta,
368 const enum hrtimer_mode mode,
369 clockid_t clock_id);
370extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
371
372/* Soft interrupt function to run the hrtimer queues: */
373extern void hrtimer_run_queues(void);
374
375/* Bootup initialization: */
376extern void __init hrtimers_init(void);
377
378/* Show pending timers: */
379extern void sysrq_timer_list_show(void);
380
381int hrtimers_prepare_cpu(unsigned int cpu);
382#ifdef CONFIG_HOTPLUG_CPU
383int hrtimers_cpu_dying(unsigned int cpu);
384#else
385#define hrtimers_cpu_dying NULL
386#endif
387
388#endif
389

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