projects/linux·blob v6.14-rc6 · refs

396 lines · 11.4 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * hrtimers - High-resolution kernel timers
4 *
5 * Copyright(C) 2005, Thomas Gleixner <[email protected]>
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(time, 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(time, ns_to_ktime(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(timer->node.expires, time);
124 timer->_softexpires = ktime_add_safe(timer->_softexpires, 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(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 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_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *),
232 clockid_t clock_id, enum hrtimer_mode mode);
233extern void hrtimer_setup_on_stack(struct hrtimer *timer,
234 enum hrtimer_restart (*function)(struct hrtimer *),
235 clockid_t clock_id, enum hrtimer_mode mode);
236extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id,
237 enum hrtimer_mode mode);
238
239#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
240extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
241#else
242static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
243#endif
244
245/* Basic timer operations: */
246extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
247 u64 range_ns, const enum hrtimer_mode mode);
248
249/**
250 * hrtimer_start - (re)start an hrtimer
251 * @timer: the timer to be added
252 * @tim: expiry time
253 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
254 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
255 * softirq based mode is considered for debug purpose only!
256 */
257static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
258 const enum hrtimer_mode mode)
259{
260 hrtimer_start_range_ns(timer, tim, 0, mode);
261}
262
263extern int hrtimer_cancel(struct hrtimer *timer);
264extern int hrtimer_try_to_cancel(struct hrtimer *timer);
265
266static inline void hrtimer_start_expires(struct hrtimer *timer,
267 enum hrtimer_mode mode)
268{
269 u64 delta;
270 ktime_t soft, hard;
271 soft = hrtimer_get_softexpires(timer);
272 hard = hrtimer_get_expires(timer);
273 delta = ktime_to_ns(ktime_sub(hard, soft));
274 hrtimer_start_range_ns(timer, soft, delta, mode);
275}
276
277void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
278 enum hrtimer_mode mode);
279
280static inline void hrtimer_restart(struct hrtimer *timer)
281{
282 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
283}
284
285/* Query timers: */
286extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
287
288/**
289 * hrtimer_get_remaining - get remaining time for the timer
290 * @timer: the timer to read
291 */
292static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
293{
294 return __hrtimer_get_remaining(timer, false);
295}
296
297extern u64 hrtimer_get_next_event(void);
298extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
299
300extern bool hrtimer_active(const struct hrtimer *timer);
301
302/**
303 * hrtimer_is_queued - check, whether the timer is on one of the queues
304 * @timer: Timer to check
305 *
306 * Returns: True if the timer is queued, false otherwise
307 *
308 * The function can be used lockless, but it gives only a current snapshot.
309 */
310static inline bool hrtimer_is_queued(struct hrtimer *timer)
311{
312 /* The READ_ONCE pairs with the update functions of timer->state */
313 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
314}
315
316/*
317 * Helper function to check, whether the timer is running the callback
318 * function
319 */
320static inline int hrtimer_callback_running(struct hrtimer *timer)
321{
322 return timer->base->running == timer;
323}
324
325/**
326 * hrtimer_update_function - Update the timer's callback function
327 * @timer: Timer to update
328 * @function: New callback function
329 *
330 * Only safe to call if the timer is not enqueued. Can be called in the callback function if the
331 * timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED).
332 */
333static inline void hrtimer_update_function(struct hrtimer *timer,
334 enum hrtimer_restart (*function)(struct hrtimer *))
335{
336 guard(raw_spinlock_irqsave)(&timer->base->cpu_base->lock);
337
338 if (WARN_ON_ONCE(hrtimer_is_queued(timer)))
339 return;
340
341 if (WARN_ON_ONCE(!function))
342 return;
343
344 timer->function = function;
345}
346
347/* Forward a hrtimer so it expires after now: */
348extern u64
349hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
350
351/**
352 * hrtimer_forward_now() - forward the timer expiry so it expires after now
353 * @timer: hrtimer to forward
354 * @interval: the interval to forward
355 *
356 * It is a variant of hrtimer_forward(). The timer will expire after the current
357 * time of the hrtimer clock base. See hrtimer_forward() for details.
358 */
359static inline u64 hrtimer_forward_now(struct hrtimer *timer,
360 ktime_t interval)
361{
362 return hrtimer_forward(timer, timer->base->get_time(), interval);
363}
364
365/* Precise sleep: */
366
367extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
368extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
369 const clockid_t clockid);
370
371extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
372 const enum hrtimer_mode mode);
373extern int schedule_hrtimeout_range_clock(ktime_t *expires,
374 u64 delta,
375 const enum hrtimer_mode mode,
376 clockid_t clock_id);
377extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
378
379/* Soft interrupt function to run the hrtimer queues: */
380extern void hrtimer_run_queues(void);
381
382/* Bootup initialization: */
383extern void __init hrtimers_init(void);
384
385/* Show pending timers: */
386extern void sysrq_timer_list_show(void);
387
388int hrtimers_prepare_cpu(unsigned int cpu);
389int hrtimers_cpu_starting(unsigned int cpu);
390#ifdef CONFIG_HOTPLUG_CPU
391int hrtimers_cpu_dying(unsigned int cpu);
392#else
393#define hrtimers_cpu_dying NULL
394#endif
395
396#endif