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1/*
2 * include/linux/hrtimer.h
3 *
4 * hrtimers - High-resolution kernel timers
5 *
6 * Copyright(C) 2005, Thomas Gleixner <[email protected]>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
8 *
9 * data type definitions, declarations, prototypes
10 *
11 * Started by: Thomas Gleixner and Ingo Molnar
12 *
13 * For licencing details see kernel-base/COPYING
14 */
15#ifndef _LINUX_HRTIMER_H
16#define _LINUX_HRTIMER_H
17
18#include <linux/rbtree.h>
19#include <linux/ktime.h>
20#include <linux/init.h>
21#include <linux/list.h>
22#include <linux/percpu.h>
23#include <linux/timer.h>
24#include <linux/timerqueue.h>
25
26struct hrtimer_clock_base;
27struct hrtimer_cpu_base;
28
29/*
30 * Mode arguments of xxx_hrtimer functions:
31 *
32 * HRTIMER_MODE_ABS - Time value is absolute
33 * HRTIMER_MODE_REL - Time value is relative to now
34 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
35 * when starting the timer)
36 * HRTIMER_MODE_SOFT - Timer callback function will be executed in
37 * soft irq context
38 */
39enum hrtimer_mode {
40 HRTIMER_MODE_ABS = 0x00,
41 HRTIMER_MODE_REL = 0x01,
42 HRTIMER_MODE_PINNED = 0x02,
43 HRTIMER_MODE_SOFT = 0x04,
44
45 HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
46 HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
47
48 HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
49 HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,
50
51 HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
52 HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,
53
54};
55
56/*
57 * Return values for the callback function
58 */
59enum hrtimer_restart {
60 HRTIMER_NORESTART, /* Timer is not restarted */
61 HRTIMER_RESTART, /* Timer must be restarted */
62};
63
64/*
65 * Values to track state of the timer
66 *
67 * Possible states:
68 *
69 * 0x00 inactive
70 * 0x01 enqueued into rbtree
71 *
72 * The callback state is not part of the timer->state because clearing it would
73 * mean touching the timer after the callback, this makes it impossible to free
74 * the timer from the callback function.
75 *
76 * Therefore we track the callback state in:
77 *
78 * timer->base->cpu_base->running == timer
79 *
80 * On SMP it is possible to have a "callback function running and enqueued"
81 * status. It happens for example when a posix timer expired and the callback
82 * queued a signal. Between dropping the lock which protects the posix timer
83 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
84 * signal and rearm the timer.
85 *
86 * All state transitions are protected by cpu_base->lock.
87 */
88#define HRTIMER_STATE_INACTIVE 0x00
89#define HRTIMER_STATE_ENQUEUED 0x01
90
91/**
92 * struct hrtimer - the basic hrtimer structure
93 * @node: timerqueue node, which also manages node.expires,
94 * the absolute expiry time in the hrtimers internal
95 * representation. The time is related to the clock on
96 * which the timer is based. Is setup by adding
97 * slack to the _softexpires value. For non range timers
98 * identical to _softexpires.
99 * @_softexpires: the absolute earliest expiry time of the hrtimer.
100 * The time which was given as expiry time when the timer
101 * was armed.
102 * @function: timer expiry callback function
103 * @base: pointer to the timer base (per cpu and per clock)
104 * @state: state information (See bit values above)
105 * @is_rel: Set if the timer was armed relative
106 * @is_soft: Set if hrtimer will be expired in soft interrupt context.
107 *
108 * The hrtimer structure must be initialized by hrtimer_init()
109 */
110struct hrtimer {
111 struct timerqueue_node node;
112 ktime_t _softexpires;
113 enum hrtimer_restart (*function)(struct hrtimer *);
114 struct hrtimer_clock_base *base;
115 u8 state;
116 u8 is_rel;
117 u8 is_soft;
118};
119
120/**
121 * struct hrtimer_sleeper - simple sleeper structure
122 * @timer: embedded timer structure
123 * @task: task to wake up
124 *
125 * task is set to NULL, when the timer expires.
126 */
127struct hrtimer_sleeper {
128 struct hrtimer timer;
129 struct task_struct *task;
130};
131
132#ifdef CONFIG_64BIT
133# define __hrtimer_clock_base_align ____cacheline_aligned
134#else
135# define __hrtimer_clock_base_align
136#endif
137
138/**
139 * struct hrtimer_clock_base - the timer base for a specific clock
140 * @cpu_base: per cpu clock base
141 * @index: clock type index for per_cpu support when moving a
142 * timer to a base on another cpu.
143 * @clockid: clock id for per_cpu support
144 * @seq: seqcount around __run_hrtimer
145 * @running: pointer to the currently running hrtimer
146 * @active: red black tree root node for the active timers
147 * @get_time: function to retrieve the current time of the clock
148 * @offset: offset of this clock to the monotonic base
149 */
150struct hrtimer_clock_base {
151 struct hrtimer_cpu_base *cpu_base;
152 unsigned int index;
153 clockid_t clockid;
154 seqcount_t seq;
155 struct hrtimer *running;
156 struct timerqueue_head active;
157 ktime_t (*get_time)(void);
158 ktime_t offset;
159} __hrtimer_clock_base_align;
160
161enum hrtimer_base_type {
162 HRTIMER_BASE_MONOTONIC,
163 HRTIMER_BASE_REALTIME,
164 HRTIMER_BASE_BOOTTIME,
165 HRTIMER_BASE_TAI,
166 HRTIMER_BASE_MONOTONIC_SOFT,
167 HRTIMER_BASE_REALTIME_SOFT,
168 HRTIMER_BASE_BOOTTIME_SOFT,
169 HRTIMER_BASE_TAI_SOFT,
170 HRTIMER_MAX_CLOCK_BASES,
171};
172
173/**
174 * struct hrtimer_cpu_base - the per cpu clock bases
175 * @lock: lock protecting the base and associated clock bases
176 * and timers
177 * @cpu: cpu number
178 * @active_bases: Bitfield to mark bases with active timers
179 * @clock_was_set_seq: Sequence counter of clock was set events
180 * @hres_active: State of high resolution mode
181 * @in_hrtirq: hrtimer_interrupt() is currently executing
182 * @hang_detected: The last hrtimer interrupt detected a hang
183 * @softirq_activated: displays, if the softirq is raised - update of softirq
184 * related settings is not required then.
185 * @nr_events: Total number of hrtimer interrupt events
186 * @nr_retries: Total number of hrtimer interrupt retries
187 * @nr_hangs: Total number of hrtimer interrupt hangs
188 * @max_hang_time: Maximum time spent in hrtimer_interrupt
189 * @expires_next: absolute time of the next event, is required for remote
190 * hrtimer enqueue; it is the total first expiry time (hard
191 * and soft hrtimer are taken into account)
192 * @next_timer: Pointer to the first expiring timer
193 * @softirq_expires_next: Time to check, if soft queues needs also to be expired
194 * @softirq_next_timer: Pointer to the first expiring softirq based timer
195 * @clock_base: array of clock bases for this cpu
196 *
197 * Note: next_timer is just an optimization for __remove_hrtimer().
198 * Do not dereference the pointer because it is not reliable on
199 * cross cpu removals.
200 */
201struct hrtimer_cpu_base {
202 raw_spinlock_t lock;
203 unsigned int cpu;
204 unsigned int active_bases;
205 unsigned int clock_was_set_seq;
206 unsigned int hres_active : 1,
207 in_hrtirq : 1,
208 hang_detected : 1,
209 softirq_activated : 1;
210#ifdef CONFIG_HIGH_RES_TIMERS
211 unsigned int nr_events;
212 unsigned short nr_retries;
213 unsigned short nr_hangs;
214 unsigned int max_hang_time;
215#endif
216 ktime_t expires_next;
217 struct hrtimer *next_timer;
218 ktime_t softirq_expires_next;
219 struct hrtimer *softirq_next_timer;
220 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
221} ____cacheline_aligned;
222
223static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
224{
225 timer->node.expires = time;
226 timer->_softexpires = time;
227}
228
229static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
230{
231 timer->_softexpires = time;
232 timer->node.expires = ktime_add_safe(time, delta);
233}
234
235static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
236{
237 timer->_softexpires = time;
238 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
239}
240
241static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
242{
243 timer->node.expires = tv64;
244 timer->_softexpires = tv64;
245}
246
247static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
248{
249 timer->node.expires = ktime_add_safe(timer->node.expires, time);
250 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
251}
252
253static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
254{
255 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
256 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
257}
258
259static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
260{
261 return timer->node.expires;
262}
263
264static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
265{
266 return timer->_softexpires;
267}
268
269static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
270{
271 return timer->node.expires;
272}
273static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
274{
275 return timer->_softexpires;
276}
277
278static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
279{
280 return ktime_to_ns(timer->node.expires);
281}
282
283static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
284{
285 return ktime_sub(timer->node.expires, timer->base->get_time());
286}
287
288static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
289{
290 return timer->base->get_time();
291}
292
293static inline int hrtimer_is_hres_active(struct hrtimer *timer)
294{
295 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
296 timer->base->cpu_base->hres_active : 0;
297}
298
299#ifdef CONFIG_HIGH_RES_TIMERS
300struct clock_event_device;
301
302extern void hrtimer_interrupt(struct clock_event_device *dev);
303
304/*
305 * The resolution of the clocks. The resolution value is returned in
306 * the clock_getres() system call to give application programmers an
307 * idea of the (in)accuracy of timers. Timer values are rounded up to
308 * this resolution values.
309 */
310# define HIGH_RES_NSEC 1
311# define KTIME_HIGH_RES (HIGH_RES_NSEC)
312# define MONOTONIC_RES_NSEC HIGH_RES_NSEC
313# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
314
315extern void clock_was_set_delayed(void);
316
317extern unsigned int hrtimer_resolution;
318
319#else
320
321# define MONOTONIC_RES_NSEC LOW_RES_NSEC
322# define KTIME_MONOTONIC_RES KTIME_LOW_RES
323
324#define hrtimer_resolution (unsigned int)LOW_RES_NSEC
325
326static inline void clock_was_set_delayed(void) { }
327
328#endif
329
330static inline ktime_t
331__hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
332{
333 ktime_t rem = ktime_sub(timer->node.expires, now);
334
335 /*
336 * Adjust relative timers for the extra we added in
337 * hrtimer_start_range_ns() to prevent short timeouts.
338 */
339 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
340 rem -= hrtimer_resolution;
341 return rem;
342}
343
344static inline ktime_t
345hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
346{
347 return __hrtimer_expires_remaining_adjusted(timer,
348 timer->base->get_time());
349}
350
351extern void clock_was_set(void);
352#ifdef CONFIG_TIMERFD
353extern void timerfd_clock_was_set(void);
354#else
355static inline void timerfd_clock_was_set(void) { }
356#endif
357extern void hrtimers_resume(void);
358
359DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
360
361
362/* Exported timer functions: */
363
364/* Initialize timers: */
365extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
366 enum hrtimer_mode mode);
367
368#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
369extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
370 enum hrtimer_mode mode);
371
372extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
373#else
374static inline void hrtimer_init_on_stack(struct hrtimer *timer,
375 clockid_t which_clock,
376 enum hrtimer_mode mode)
377{
378 hrtimer_init(timer, which_clock, mode);
379}
380static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
381#endif
382
383/* Basic timer operations: */
384extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
385 u64 range_ns, const enum hrtimer_mode mode);
386
387/**
388 * hrtimer_start - (re)start an hrtimer
389 * @timer: the timer to be added
390 * @tim: expiry time
391 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
392 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
393 * softirq based mode is considered for debug purpose only!
394 */
395static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
396 const enum hrtimer_mode mode)
397{
398 hrtimer_start_range_ns(timer, tim, 0, mode);
399}
400
401extern int hrtimer_cancel(struct hrtimer *timer);
402extern int hrtimer_try_to_cancel(struct hrtimer *timer);
403
404static inline void hrtimer_start_expires(struct hrtimer *timer,
405 enum hrtimer_mode mode)
406{
407 u64 delta;
408 ktime_t soft, hard;
409 soft = hrtimer_get_softexpires(timer);
410 hard = hrtimer_get_expires(timer);
411 delta = ktime_to_ns(ktime_sub(hard, soft));
412 hrtimer_start_range_ns(timer, soft, delta, mode);
413}
414
415static inline void hrtimer_restart(struct hrtimer *timer)
416{
417 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
418}
419
420/* Query timers: */
421extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
422
423static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
424{
425 return __hrtimer_get_remaining(timer, false);
426}
427
428extern u64 hrtimer_get_next_event(void);
429extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
430
431extern bool hrtimer_active(const struct hrtimer *timer);
432
433/*
434 * Helper function to check, whether the timer is on one of the queues
435 */
436static inline int hrtimer_is_queued(struct hrtimer *timer)
437{
438 return timer->state & HRTIMER_STATE_ENQUEUED;
439}
440
441/*
442 * Helper function to check, whether the timer is running the callback
443 * function
444 */
445static inline int hrtimer_callback_running(struct hrtimer *timer)
446{
447 return timer->base->running == timer;
448}
449
450/* Forward a hrtimer so it expires after now: */
451extern u64
452hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
453
454/**
455 * hrtimer_forward_now - forward the timer expiry so it expires after now
456 * @timer: hrtimer to forward
457 * @interval: the interval to forward
458 *
459 * Forward the timer expiry so it will expire after the current time
460 * of the hrtimer clock base. Returns the number of overruns.
461 *
462 * Can be safely called from the callback function of @timer. If
463 * called from other contexts @timer must neither be enqueued nor
464 * running the callback and the caller needs to take care of
465 * serialization.
466 *
467 * Note: This only updates the timer expiry value and does not requeue
468 * the timer.
469 */
470static inline u64 hrtimer_forward_now(struct hrtimer *timer,
471 ktime_t interval)
472{
473 return hrtimer_forward(timer, timer->base->get_time(), interval);
474}
475
476/* Precise sleep: */
477
478extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
479extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
480 const enum hrtimer_mode mode,
481 const clockid_t clockid);
482
483extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
484 struct task_struct *tsk);
485
486extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
487 const enum hrtimer_mode mode);
488extern int schedule_hrtimeout_range_clock(ktime_t *expires,
489 u64 delta,
490 const enum hrtimer_mode mode,
491 clockid_t clock_id);
492extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
493
494/* Soft interrupt function to run the hrtimer queues: */
495extern void hrtimer_run_queues(void);
496
497/* Bootup initialization: */
498extern void __init hrtimers_init(void);
499
500/* Show pending timers: */
501extern void sysrq_timer_list_show(void);
502
503int hrtimers_prepare_cpu(unsigned int cpu);
504#ifdef CONFIG_HOTPLUG_CPU
505int hrtimers_dead_cpu(unsigned int cpu);
506#else
507#define hrtimers_dead_cpu NULL
508#endif
509
510#endif