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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * hrtimers - High-resolution kernel timers
4 *
5 * Copyright(C) 2005, Linutronix GmbH, Thomas Gleixner <tglx@kernel.org>
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_add_expires(struct hrtimer *timer, ktime_t time)
116{
117 timer->node.expires = ktime_add_safe(timer->node.expires, time);
118 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
119}
120
121static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
122{
123 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
124 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
125}
126
127static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
128{
129 return timer->node.expires;
130}
131
132static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
133{
134 return timer->_softexpires;
135}
136
137static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
138{
139 return ktime_to_ns(timer->node.expires);
140}
141
142ktime_t hrtimer_cb_get_time(const struct hrtimer *timer);
143
144static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
145{
146 return ktime_sub(timer->node.expires, hrtimer_cb_get_time(timer));
147}
148
149static inline int hrtimer_is_hres_active(struct hrtimer *timer)
150{
151 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
152 timer->base->cpu_base->hres_active : 0;
153}
154
155#ifdef CONFIG_HIGH_RES_TIMERS
156struct clock_event_device;
157
158extern void hrtimer_interrupt(struct clock_event_device *dev);
159
160extern unsigned int hrtimer_resolution;
161
162#else
163
164#define hrtimer_resolution (unsigned int)LOW_RES_NSEC
165
166#endif
167
168static inline ktime_t
169__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
170{
171 ktime_t rem = ktime_sub(timer->node.expires, now);
172
173 /*
174 * Adjust relative timers for the extra we added in
175 * hrtimer_start_range_ns() to prevent short timeouts.
176 */
177 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
178 rem -= hrtimer_resolution;
179 return rem;
180}
181
182static inline ktime_t
183hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
184{
185 return __hrtimer_expires_remaining_adjusted(timer, hrtimer_cb_get_time(timer));
186}
187
188#ifdef CONFIG_TIMERFD
189extern void timerfd_clock_was_set(void);
190extern void timerfd_resume(void);
191#else
192static inline void timerfd_clock_was_set(void) { }
193static inline void timerfd_resume(void) { }
194#endif
195
196DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
197
198#ifdef CONFIG_PREEMPT_RT
199void hrtimer_cancel_wait_running(const struct hrtimer *timer);
200#else
201static inline void hrtimer_cancel_wait_running(struct hrtimer *timer)
202{
203 cpu_relax();
204}
205#endif
206
207static inline enum hrtimer_restart hrtimer_dummy_timeout(struct hrtimer *unused)
208{
209 return HRTIMER_NORESTART;
210}
211
212/* Exported timer functions: */
213
214/* Initialize timers: */
215extern void hrtimer_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *),
216 clockid_t clock_id, enum hrtimer_mode mode);
217extern void hrtimer_setup_on_stack(struct hrtimer *timer,
218 enum hrtimer_restart (*function)(struct hrtimer *),
219 clockid_t clock_id, enum hrtimer_mode mode);
220extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id,
221 enum hrtimer_mode mode);
222
223#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
224extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
225#else
226static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
227#endif
228
229/* Basic timer operations: */
230extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
231 u64 range_ns, const enum hrtimer_mode mode);
232
233/**
234 * hrtimer_start - (re)start an hrtimer
235 * @timer: the timer to be added
236 * @tim: expiry time
237 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
238 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
239 * softirq based mode is considered for debug purpose only!
240 */
241static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
242 const enum hrtimer_mode mode)
243{
244 hrtimer_start_range_ns(timer, tim, 0, mode);
245}
246
247extern int hrtimer_cancel(struct hrtimer *timer);
248extern int hrtimer_try_to_cancel(struct hrtimer *timer);
249
250static inline void hrtimer_start_expires(struct hrtimer *timer,
251 enum hrtimer_mode mode)
252{
253 u64 delta;
254 ktime_t soft, hard;
255 soft = hrtimer_get_softexpires(timer);
256 hard = hrtimer_get_expires(timer);
257 delta = ktime_to_ns(ktime_sub(hard, soft));
258 hrtimer_start_range_ns(timer, soft, delta, mode);
259}
260
261void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
262 enum hrtimer_mode mode);
263
264static inline void hrtimer_restart(struct hrtimer *timer)
265{
266 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
267}
268
269/* Query timers: */
270extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
271
272/**
273 * hrtimer_get_remaining - get remaining time for the timer
274 * @timer: the timer to read
275 */
276static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
277{
278 return __hrtimer_get_remaining(timer, false);
279}
280
281extern u64 hrtimer_get_next_event(void);
282extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
283
284extern bool hrtimer_active(const struct hrtimer *timer);
285
286/**
287 * hrtimer_is_queued - check, whether the timer is on one of the queues
288 * @timer: Timer to check
289 *
290 * Returns: True if the timer is queued, false otherwise
291 *
292 * The function can be used lockless, but it gives only a current snapshot.
293 */
294static inline bool hrtimer_is_queued(struct hrtimer *timer)
295{
296 /* The READ_ONCE pairs with the update functions of timer->state */
297 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
298}
299
300/*
301 * Helper function to check, whether the timer is running the callback
302 * function
303 */
304static inline int hrtimer_callback_running(struct hrtimer *timer)
305{
306 return timer->base->running == timer;
307}
308
309/**
310 * hrtimer_update_function - Update the timer's callback function
311 * @timer: Timer to update
312 * @function: New callback function
313 *
314 * Only safe to call if the timer is not enqueued. Can be called in the callback function if the
315 * timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED).
316 */
317static inline void hrtimer_update_function(struct hrtimer *timer,
318 enum hrtimer_restart (*function)(struct hrtimer *))
319{
320#ifdef CONFIG_PROVE_LOCKING
321 guard(raw_spinlock_irqsave)(&timer->base->cpu_base->lock);
322
323 if (WARN_ON_ONCE(hrtimer_is_queued(timer)))
324 return;
325
326 if (WARN_ON_ONCE(!function))
327 return;
328#endif
329 ACCESS_PRIVATE(timer, function) = function;
330}
331
332/* Forward a hrtimer so it expires after now: */
333extern u64
334hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
335
336/**
337 * hrtimer_forward_now() - forward the timer expiry so it expires after now
338 * @timer: hrtimer to forward
339 * @interval: the interval to forward
340 *
341 * It is a variant of hrtimer_forward(). The timer will expire after the current
342 * time of the hrtimer clock base. See hrtimer_forward() for details.
343 */
344static inline u64 hrtimer_forward_now(struct hrtimer *timer,
345 ktime_t interval)
346{
347 return hrtimer_forward(timer, hrtimer_cb_get_time(timer), interval);
348}
349
350/* Precise sleep: */
351
352extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
353extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
354 const clockid_t clockid);
355
356extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
357 const enum hrtimer_mode mode);
358extern int schedule_hrtimeout_range_clock(ktime_t *expires,
359 u64 delta,
360 const enum hrtimer_mode mode,
361 clockid_t clock_id);
362extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
363
364/* Soft interrupt function to run the hrtimer queues: */
365extern void hrtimer_run_queues(void);
366
367/* Bootup initialization: */
368extern void __init hrtimers_init(void);
369
370/* Show pending timers: */
371extern void sysrq_timer_list_show(void);
372
373int hrtimers_prepare_cpu(unsigned int cpu);
374int hrtimers_cpu_starting(unsigned int cpu);
375#ifdef CONFIG_HOTPLUG_CPU
376int hrtimers_cpu_dying(unsigned int cpu);
377#else
378#define hrtimers_cpu_dying NULL
379#endif
380
381#endif