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/rbtree.h>
16#include <linux/ktime.h>
17#include <linux/init.h>
18#include <linux/list.h>
19#include <linux/percpu.h>
20#include <linux/timer.h>
21#include <linux/timerqueue.h>
22
23struct hrtimer_clock_base;
24struct hrtimer_cpu_base;
25
26/*
27 * Mode arguments of xxx_hrtimer functions:
28 *
29 * HRTIMER_MODE_ABS - Time value is absolute
30 * HRTIMER_MODE_REL - Time value is relative to now
31 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
32 * when starting the timer)
33 * HRTIMER_MODE_SOFT - Timer callback function will be executed in
34 * soft irq context
35 */
36enum hrtimer_mode {
37 HRTIMER_MODE_ABS = 0x00,
38 HRTIMER_MODE_REL = 0x01,
39 HRTIMER_MODE_PINNED = 0x02,
40 HRTIMER_MODE_SOFT = 0x04,
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};
52
53/*
54 * Return values for the callback function
55 */
56enum hrtimer_restart {
57 HRTIMER_NORESTART, /* Timer is not restarted */
58 HRTIMER_RESTART, /* Timer must be restarted */
59};
60
61/*
62 * Values to track state of the timer
63 *
64 * Possible states:
65 *
66 * 0x00 inactive
67 * 0x01 enqueued into rbtree
68 *
69 * The callback state is not part of the timer->state because clearing it would
70 * mean touching the timer after the callback, this makes it impossible to free
71 * the timer from the callback function.
72 *
73 * Therefore we track the callback state in:
74 *
75 * timer->base->cpu_base->running == timer
76 *
77 * On SMP it is possible to have a "callback function running and enqueued"
78 * status. It happens for example when a posix timer expired and the callback
79 * queued a signal. Between dropping the lock which protects the posix timer
80 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
81 * signal and rearm the timer.
82 *
83 * All state transitions are protected by cpu_base->lock.
84 */
85#define HRTIMER_STATE_INACTIVE 0x00
86#define HRTIMER_STATE_ENQUEUED 0x01
87
88/**
89 * struct hrtimer - the basic hrtimer structure
90 * @node: timerqueue node, which also manages node.expires,
91 * the absolute expiry time in the hrtimers internal
92 * representation. The time is related to the clock on
93 * which the timer is based. Is setup by adding
94 * slack to the _softexpires value. For non range timers
95 * identical to _softexpires.
96 * @_softexpires: the absolute earliest expiry time of the hrtimer.
97 * The time which was given as expiry time when the timer
98 * was armed.
99 * @function: timer expiry callback function
100 * @base: pointer to the timer base (per cpu and per clock)
101 * @state: state information (See bit values above)
102 * @is_rel: Set if the timer was armed relative
103 * @is_soft: Set if hrtimer will be expired in soft interrupt context.
104 *
105 * The hrtimer structure must be initialized by hrtimer_init()
106 */
107struct hrtimer {
108 struct timerqueue_node node;
109 ktime_t _softexpires;
110 enum hrtimer_restart (*function)(struct hrtimer *);
111 struct hrtimer_clock_base *base;
112 u8 state;
113 u8 is_rel;
114 u8 is_soft;
115};
116
117/**
118 * struct hrtimer_sleeper - simple sleeper structure
119 * @timer: embedded timer structure
120 * @task: task to wake up
121 *
122 * task is set to NULL, when the timer expires.
123 */
124struct hrtimer_sleeper {
125 struct hrtimer timer;
126 struct task_struct *task;
127};
128
129#ifdef CONFIG_64BIT
130# define __hrtimer_clock_base_align ____cacheline_aligned
131#else
132# define __hrtimer_clock_base_align
133#endif
134
135/**
136 * struct hrtimer_clock_base - the timer base for a specific clock
137 * @cpu_base: per cpu clock base
138 * @index: clock type index for per_cpu support when moving a
139 * timer to a base on another cpu.
140 * @clockid: clock id for per_cpu support
141 * @seq: seqcount around __run_hrtimer
142 * @running: pointer to the currently running hrtimer
143 * @active: red black tree root node for the active timers
144 * @get_time: function to retrieve the current time of the clock
145 * @offset: offset of this clock to the monotonic base
146 */
147struct hrtimer_clock_base {
148 struct hrtimer_cpu_base *cpu_base;
149 unsigned int index;
150 clockid_t clockid;
151 seqcount_t seq;
152 struct hrtimer *running;
153 struct timerqueue_head active;
154 ktime_t (*get_time)(void);
155 ktime_t offset;
156} __hrtimer_clock_base_align;
157
158enum hrtimer_base_type {
159 HRTIMER_BASE_MONOTONIC,
160 HRTIMER_BASE_REALTIME,
161 HRTIMER_BASE_BOOTTIME,
162 HRTIMER_BASE_TAI,
163 HRTIMER_BASE_MONOTONIC_SOFT,
164 HRTIMER_BASE_REALTIME_SOFT,
165 HRTIMER_BASE_BOOTTIME_SOFT,
166 HRTIMER_BASE_TAI_SOFT,
167 HRTIMER_MAX_CLOCK_BASES,
168};
169
170/**
171 * struct hrtimer_cpu_base - the per cpu clock bases
172 * @lock: lock protecting the base and associated clock bases
173 * and timers
174 * @cpu: cpu number
175 * @active_bases: Bitfield to mark bases with active timers
176 * @clock_was_set_seq: Sequence counter of clock was set events
177 * @hres_active: State of high resolution mode
178 * @in_hrtirq: hrtimer_interrupt() is currently executing
179 * @hang_detected: The last hrtimer interrupt detected a hang
180 * @softirq_activated: displays, if the softirq is raised - update of softirq
181 * related settings is not required then.
182 * @nr_events: Total number of hrtimer interrupt events
183 * @nr_retries: Total number of hrtimer interrupt retries
184 * @nr_hangs: Total number of hrtimer interrupt hangs
185 * @max_hang_time: Maximum time spent in hrtimer_interrupt
186 * @expires_next: absolute time of the next event, is required for remote
187 * hrtimer enqueue; it is the total first expiry time (hard
188 * and soft hrtimer are taken into account)
189 * @next_timer: Pointer to the first expiring timer
190 * @softirq_expires_next: Time to check, if soft queues needs also to be expired
191 * @softirq_next_timer: Pointer to the first expiring softirq based timer
192 * @clock_base: array of clock bases for this cpu
193 *
194 * Note: next_timer is just an optimization for __remove_hrtimer().
195 * Do not dereference the pointer because it is not reliable on
196 * cross cpu removals.
197 */
198struct hrtimer_cpu_base {
199 raw_spinlock_t lock;
200 unsigned int cpu;
201 unsigned int active_bases;
202 unsigned int clock_was_set_seq;
203 unsigned int hres_active : 1,
204 in_hrtirq : 1,
205 hang_detected : 1,
206 softirq_activated : 1;
207#ifdef CONFIG_HIGH_RES_TIMERS
208 unsigned int nr_events;
209 unsigned short nr_retries;
210 unsigned short nr_hangs;
211 unsigned int max_hang_time;
212#endif
213 ktime_t expires_next;
214 struct hrtimer *next_timer;
215 ktime_t softirq_expires_next;
216 struct hrtimer *softirq_next_timer;
217 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
218} ____cacheline_aligned;
219
220static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
221{
222 timer->node.expires = time;
223 timer->_softexpires = time;
224}
225
226static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
227{
228 timer->_softexpires = time;
229 timer->node.expires = ktime_add_safe(time, delta);
230}
231
232static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
233{
234 timer->_softexpires = time;
235 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
236}
237
238static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
239{
240 timer->node.expires = tv64;
241 timer->_softexpires = tv64;
242}
243
244static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
245{
246 timer->node.expires = ktime_add_safe(timer->node.expires, time);
247 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
248}
249
250static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
251{
252 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
253 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
254}
255
256static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
257{
258 return timer->node.expires;
259}
260
261static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
262{
263 return timer->_softexpires;
264}
265
266static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
267{
268 return timer->node.expires;
269}
270static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
271{
272 return timer->_softexpires;
273}
274
275static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
276{
277 return ktime_to_ns(timer->node.expires);
278}
279
280static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
281{
282 return ktime_sub(timer->node.expires, timer->base->get_time());
283}
284
285static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
286{
287 return timer->base->get_time();
288}
289
290static inline int hrtimer_is_hres_active(struct hrtimer *timer)
291{
292 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
293 timer->base->cpu_base->hres_active : 0;
294}
295
296#ifdef CONFIG_HIGH_RES_TIMERS
297struct clock_event_device;
298
299extern void hrtimer_interrupt(struct clock_event_device *dev);
300
301/*
302 * The resolution of the clocks. The resolution value is returned in
303 * the clock_getres() system call to give application programmers an
304 * idea of the (in)accuracy of timers. Timer values are rounded up to
305 * this resolution values.
306 */
307# define HIGH_RES_NSEC 1
308# define KTIME_HIGH_RES (HIGH_RES_NSEC)
309# define MONOTONIC_RES_NSEC HIGH_RES_NSEC
310# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
311
312extern void clock_was_set_delayed(void);
313
314extern unsigned int hrtimer_resolution;
315
316#else
317
318# define MONOTONIC_RES_NSEC LOW_RES_NSEC
319# define KTIME_MONOTONIC_RES KTIME_LOW_RES
320
321#define hrtimer_resolution (unsigned int)LOW_RES_NSEC
322
323static inline void clock_was_set_delayed(void) { }
324
325#endif
326
327static inline ktime_t
328__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
329{
330 ktime_t rem = ktime_sub(timer->node.expires, now);
331
332 /*
333 * Adjust relative timers for the extra we added in
334 * hrtimer_start_range_ns() to prevent short timeouts.
335 */
336 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
337 rem -= hrtimer_resolution;
338 return rem;
339}
340
341static inline ktime_t
342hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
343{
344 return __hrtimer_expires_remaining_adjusted(timer,
345 timer->base->get_time());
346}
347
348extern void clock_was_set(void);
349#ifdef CONFIG_TIMERFD
350extern void timerfd_clock_was_set(void);
351#else
352static inline void timerfd_clock_was_set(void) { }
353#endif
354extern void hrtimers_resume(void);
355
356DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
357
358
359/* Exported timer functions: */
360
361/* Initialize timers: */
362extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
363 enum hrtimer_mode mode);
364
365#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
366extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
367 enum hrtimer_mode mode);
368
369extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
370#else
371static inline void hrtimer_init_on_stack(struct hrtimer *timer,
372 clockid_t which_clock,
373 enum hrtimer_mode mode)
374{
375 hrtimer_init(timer, which_clock, mode);
376}
377static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
378#endif
379
380/* Basic timer operations: */
381extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
382 u64 range_ns, const enum hrtimer_mode mode);
383
384/**
385 * hrtimer_start - (re)start an hrtimer
386 * @timer: the timer to be added
387 * @tim: expiry time
388 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
389 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
390 * softirq based mode is considered for debug purpose only!
391 */
392static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
393 const enum hrtimer_mode mode)
394{
395 hrtimer_start_range_ns(timer, tim, 0, mode);
396}
397
398extern int hrtimer_cancel(struct hrtimer *timer);
399extern int hrtimer_try_to_cancel(struct hrtimer *timer);
400
401static inline void hrtimer_start_expires(struct hrtimer *timer,
402 enum hrtimer_mode mode)
403{
404 u64 delta;
405 ktime_t soft, hard;
406 soft = hrtimer_get_softexpires(timer);
407 hard = hrtimer_get_expires(timer);
408 delta = ktime_to_ns(ktime_sub(hard, soft));
409 hrtimer_start_range_ns(timer, soft, delta, mode);
410}
411
412static inline void hrtimer_restart(struct hrtimer *timer)
413{
414 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
415}
416
417/* Query timers: */
418extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
419
420static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
421{
422 return __hrtimer_get_remaining(timer, false);
423}
424
425extern u64 hrtimer_get_next_event(void);
426extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
427
428extern bool hrtimer_active(const struct hrtimer *timer);
429
430/*
431 * Helper function to check, whether the timer is on one of the queues
432 */
433static inline int hrtimer_is_queued(struct hrtimer *timer)
434{
435 return timer->state & HRTIMER_STATE_ENQUEUED;
436}
437
438/*
439 * Helper function to check, whether the timer is running the callback
440 * function
441 */
442static inline int hrtimer_callback_running(struct hrtimer *timer)
443{
444 return timer->base->running == timer;
445}
446
447/* Forward a hrtimer so it expires after now: */
448extern u64
449hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
450
451/**
452 * hrtimer_forward_now - forward the timer expiry so it expires after now
453 * @timer: hrtimer to forward
454 * @interval: the interval to forward
455 *
456 * Forward the timer expiry so it will expire after the current time
457 * of the hrtimer clock base. Returns the number of overruns.
458 *
459 * Can be safely called from the callback function of @timer. If
460 * called from other contexts @timer must neither be enqueued nor
461 * running the callback and the caller needs to take care of
462 * serialization.
463 *
464 * Note: This only updates the timer expiry value and does not requeue
465 * the timer.
466 */
467static inline u64 hrtimer_forward_now(struct hrtimer *timer,
468 ktime_t interval)
469{
470 return hrtimer_forward(timer, timer->base->get_time(), interval);
471}
472
473/* Precise sleep: */
474
475extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
476extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
477 const enum hrtimer_mode mode,
478 const clockid_t clockid);
479
480extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
481 struct task_struct *tsk);
482
483extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
484 const enum hrtimer_mode mode);
485extern int schedule_hrtimeout_range_clock(ktime_t *expires,
486 u64 delta,
487 const enum hrtimer_mode mode,
488 clockid_t clock_id);
489extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
490
491/* Soft interrupt function to run the hrtimer queues: */
492extern void hrtimer_run_queues(void);
493
494/* Bootup initialization: */
495extern void __init hrtimers_init(void);
496
497/* Show pending timers: */
498extern void sysrq_timer_list_show(void);
499
500int hrtimers_prepare_cpu(unsigned int cpu);
501#ifdef CONFIG_HOTPLUG_CPU
502int hrtimers_dead_cpu(unsigned int cpu);
503#else
504#define hrtimers_dead_cpu NULL
505#endif
506
507#endif
508