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
157ktime_t hrtimer_cb_get_time(const struct hrtimer *timer);
158
159static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
160{
161 return ktime_sub(timer->node.expires, hrtimer_cb_get_time(timer));
162}
163
164static inline int hrtimer_is_hres_active(struct hrtimer *timer)
165{
166 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
167 timer->base->cpu_base->hres_active : 0;
168}
169
170#ifdef CONFIG_HIGH_RES_TIMERS
171struct clock_event_device;
172
173extern void hrtimer_interrupt(struct clock_event_device *dev);
174
175extern unsigned int hrtimer_resolution;
176
177#else
178
179#define hrtimer_resolution (unsigned int)LOW_RES_NSEC
180
181#endif
182
183static inline ktime_t
184__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
185{
186 ktime_t rem = ktime_sub(timer->node.expires, now);
187
188 /*
189 * Adjust relative timers for the extra we added in
190 * hrtimer_start_range_ns() to prevent short timeouts.
191 */
192 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
193 rem -= hrtimer_resolution;
194 return rem;
195}
196
197static inline ktime_t
198hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
199{
200 return __hrtimer_expires_remaining_adjusted(timer, now: hrtimer_cb_get_time(timer));
201}
202
203#ifdef CONFIG_TIMERFD
204extern void timerfd_clock_was_set(void);
205extern void timerfd_resume(void);
206#else
207static inline void timerfd_clock_was_set(void) { }
208static inline void timerfd_resume(void) { }
209#endif
210
211DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
212
213#ifdef CONFIG_PREEMPT_RT
214void hrtimer_cancel_wait_running(const struct hrtimer *timer);
215#else
216static inline void hrtimer_cancel_wait_running(struct hrtimer *timer)
217{
218 cpu_relax();
219}
220#endif
221
222static inline enum hrtimer_restart hrtimer_dummy_timeout(struct hrtimer *unused)
223{
224 return HRTIMER_NORESTART;
225}
226
227/* Exported timer functions: */
228
229/* Initialize timers: */
230extern void hrtimer_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *),
231 clockid_t clock_id, enum hrtimer_mode mode);
232extern void hrtimer_setup_on_stack(struct hrtimer *timer,
233 enum hrtimer_restart (*function)(struct hrtimer *),
234 clockid_t clock_id, enum hrtimer_mode mode);
235extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id,
236 enum hrtimer_mode mode);
237
238#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
239extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
240#else
241static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
242#endif
243
244/* Basic timer operations: */
245extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
246 u64 range_ns, const enum hrtimer_mode mode);
247
248/**
249 * hrtimer_start - (re)start an hrtimer
250 * @timer: the timer to be added
251 * @tim: expiry time
252 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
253 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
254 * softirq based mode is considered for debug purpose only!
255 */
256static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
257 const enum hrtimer_mode mode)
258{
259 hrtimer_start_range_ns(timer, tim, range_ns: 0, mode);
260}
261
262extern int hrtimer_cancel(struct hrtimer *timer);
263extern int hrtimer_try_to_cancel(struct hrtimer *timer);
264
265static inline void hrtimer_start_expires(struct hrtimer *timer,
266 enum hrtimer_mode mode)
267{
268 u64 delta;
269 ktime_t soft, hard;
270 soft = hrtimer_get_softexpires(timer);
271 hard = hrtimer_get_expires(timer);
272 delta = ktime_to_ns(ktime_sub(hard, soft));
273 hrtimer_start_range_ns(timer, tim: soft, range_ns: delta, mode);
274}
275
276void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
277 enum hrtimer_mode mode);
278
279static inline void hrtimer_restart(struct hrtimer *timer)
280{
281 hrtimer_start_expires(timer, mode: HRTIMER_MODE_ABS);
282}
283
284/* Query timers: */
285extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
286
287/**
288 * hrtimer_get_remaining - get remaining time for the timer
289 * @timer: the timer to read
290 */
291static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
292{
293 return __hrtimer_get_remaining(timer, adjust: false);
294}
295
296extern u64 hrtimer_get_next_event(void);
297extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
298
299extern bool hrtimer_active(const struct hrtimer *timer);
300
301/**
302 * hrtimer_is_queued - check, whether the timer is on one of the queues
303 * @timer: Timer to check
304 *
305 * Returns: True if the timer is queued, false otherwise
306 *
307 * The function can be used lockless, but it gives only a current snapshot.
308 */
309static inline bool hrtimer_is_queued(struct hrtimer *timer)
310{
311 /* The READ_ONCE pairs with the update functions of timer->state */
312 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
313}
314
315/*
316 * Helper function to check, whether the timer is running the callback
317 * function
318 */
319static inline int hrtimer_callback_running(struct hrtimer *timer)
320{
321 return timer->base->running == timer;
322}
323
324/**
325 * hrtimer_update_function - Update the timer's callback function
326 * @timer: Timer to update
327 * @function: New callback function
328 *
329 * Only safe to call if the timer is not enqueued. Can be called in the callback function if the
330 * timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED).
331 */
332static inline void hrtimer_update_function(struct hrtimer *timer,
333 enum hrtimer_restart (*function)(struct hrtimer *))
334{
335#ifdef CONFIG_PROVE_LOCKING
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#endif
344 ACCESS_PRIVATE(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, now: hrtimer_cb_get_time(timer), 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
397