Line data Source code
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/rbtree.h>
17 : #include <linux/init.h>
18 : #include <linux/list.h>
19 : #include <linux/percpu.h>
20 : #include <linux/seqlock.h>
21 : #include <linux/timer.h>
22 : #include <linux/timerqueue.h>
23 :
24 : struct hrtimer_clock_base;
25 : struct hrtimer_cpu_base;
26 :
27 : /*
28 : * Mode arguments of xxx_hrtimer functions:
29 : *
30 : * HRTIMER_MODE_ABS - Time value is absolute
31 : * HRTIMER_MODE_REL - Time value is relative to now
32 : * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
33 : * when starting the timer)
34 : * HRTIMER_MODE_SOFT - Timer callback function will be executed in
35 : * soft irq context
36 : * HRTIMER_MODE_HARD - Timer callback function will be executed in
37 : * hard irq context even on PREEMPT_RT.
38 : */
39 : enum hrtimer_mode {
40 : HRTIMER_MODE_ABS = 0x00,
41 : HRTIMER_MODE_REL = 0x01,
42 : HRTIMER_MODE_PINNED = 0x02,
43 : HRTIMER_MODE_SOFT = 0x04,
44 : HRTIMER_MODE_HARD = 0x08,
45 :
46 : HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
47 : HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
48 :
49 : HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
50 : HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,
51 :
52 : HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
53 : HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,
54 :
55 : HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD,
56 : HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD,
57 :
58 : HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD,
59 : HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD,
60 : };
61 :
62 : /*
63 : * Return values for the callback function
64 : */
65 : enum hrtimer_restart {
66 : HRTIMER_NORESTART, /* Timer is not restarted */
67 : HRTIMER_RESTART, /* Timer must be restarted */
68 : };
69 :
70 : /*
71 : * Values to track state of the timer
72 : *
73 : * Possible states:
74 : *
75 : * 0x00 inactive
76 : * 0x01 enqueued into rbtree
77 : *
78 : * The callback state is not part of the timer->state because clearing it would
79 : * mean touching the timer after the callback, this makes it impossible to free
80 : * the timer from the callback function.
81 : *
82 : * Therefore we track the callback state in:
83 : *
84 : * timer->base->cpu_base->running == timer
85 : *
86 : * On SMP it is possible to have a "callback function running and enqueued"
87 : * status. It happens for example when a posix timer expired and the callback
88 : * queued a signal. Between dropping the lock which protects the posix timer
89 : * and reacquiring the base lock of the hrtimer, another CPU can deliver the
90 : * signal and rearm the timer.
91 : *
92 : * All state transitions are protected by cpu_base->lock.
93 : */
94 : #define HRTIMER_STATE_INACTIVE 0x00
95 : #define HRTIMER_STATE_ENQUEUED 0x01
96 :
97 : /**
98 : * struct hrtimer - the basic hrtimer structure
99 : * @node: timerqueue node, which also manages node.expires,
100 : * the absolute expiry time in the hrtimers internal
101 : * representation. The time is related to the clock on
102 : * which the timer is based. Is setup by adding
103 : * slack to the _softexpires value. For non range timers
104 : * identical to _softexpires.
105 : * @_softexpires: the absolute earliest expiry time of the hrtimer.
106 : * The time which was given as expiry time when the timer
107 : * was armed.
108 : * @function: timer expiry callback function
109 : * @base: pointer to the timer base (per cpu and per clock)
110 : * @state: state information (See bit values above)
111 : * @is_rel: Set if the timer was armed relative
112 : * @is_soft: Set if hrtimer will be expired in soft interrupt context.
113 : * @is_hard: Set if hrtimer will be expired in hard interrupt context
114 : * even on RT.
115 : *
116 : * The hrtimer structure must be initialized by hrtimer_init()
117 : */
118 : struct hrtimer {
119 : struct timerqueue_node node;
120 : ktime_t _softexpires;
121 : enum hrtimer_restart (*function)(struct hrtimer *);
122 : struct hrtimer_clock_base *base;
123 : u8 state;
124 : u8 is_rel;
125 : u8 is_soft;
126 : u8 is_hard;
127 : };
128 :
129 : /**
130 : * struct hrtimer_sleeper - simple sleeper structure
131 : * @timer: embedded timer structure
132 : * @task: task to wake up
133 : *
134 : * task is set to NULL, when the timer expires.
135 : */
136 : struct hrtimer_sleeper {
137 : struct hrtimer timer;
138 : struct task_struct *task;
139 : };
140 :
141 : #ifdef CONFIG_64BIT
142 : # define __hrtimer_clock_base_align ____cacheline_aligned
143 : #else
144 : # define __hrtimer_clock_base_align
145 : #endif
146 :
147 : /**
148 : * struct hrtimer_clock_base - the timer base for a specific clock
149 : * @cpu_base: per cpu clock base
150 : * @index: clock type index for per_cpu support when moving a
151 : * timer to a base on another cpu.
152 : * @clockid: clock id for per_cpu support
153 : * @seq: seqcount around __run_hrtimer
154 : * @running: pointer to the currently running hrtimer
155 : * @active: red black tree root node for the active timers
156 : * @get_time: function to retrieve the current time of the clock
157 : * @offset: offset of this clock to the monotonic base
158 : */
159 : struct hrtimer_clock_base {
160 : struct hrtimer_cpu_base *cpu_base;
161 : unsigned int index;
162 : clockid_t clockid;
163 : seqcount_raw_spinlock_t seq;
164 : struct hrtimer *running;
165 : struct timerqueue_head active;
166 : ktime_t (*get_time)(void);
167 : ktime_t offset;
168 : } __hrtimer_clock_base_align;
169 :
170 : enum hrtimer_base_type {
171 : HRTIMER_BASE_MONOTONIC,
172 : HRTIMER_BASE_REALTIME,
173 : HRTIMER_BASE_BOOTTIME,
174 : HRTIMER_BASE_TAI,
175 : HRTIMER_BASE_MONOTONIC_SOFT,
176 : HRTIMER_BASE_REALTIME_SOFT,
177 : HRTIMER_BASE_BOOTTIME_SOFT,
178 : HRTIMER_BASE_TAI_SOFT,
179 : HRTIMER_MAX_CLOCK_BASES,
180 : };
181 :
182 : /**
183 : * struct hrtimer_cpu_base - the per cpu clock bases
184 : * @lock: lock protecting the base and associated clock bases
185 : * and timers
186 : * @cpu: cpu number
187 : * @active_bases: Bitfield to mark bases with active timers
188 : * @clock_was_set_seq: Sequence counter of clock was set events
189 : * @hres_active: State of high resolution mode
190 : * @in_hrtirq: hrtimer_interrupt() is currently executing
191 : * @hang_detected: The last hrtimer interrupt detected a hang
192 : * @softirq_activated: displays, if the softirq is raised - update of softirq
193 : * related settings is not required then.
194 : * @nr_events: Total number of hrtimer interrupt events
195 : * @nr_retries: Total number of hrtimer interrupt retries
196 : * @nr_hangs: Total number of hrtimer interrupt hangs
197 : * @max_hang_time: Maximum time spent in hrtimer_interrupt
198 : * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are
199 : * expired
200 : * @timer_waiters: A hrtimer_cancel() invocation waits for the timer
201 : * callback to finish.
202 : * @expires_next: absolute time of the next event, is required for remote
203 : * hrtimer enqueue; it is the total first expiry time (hard
204 : * and soft hrtimer are taken into account)
205 : * @next_timer: Pointer to the first expiring timer
206 : * @softirq_expires_next: Time to check, if soft queues needs also to be expired
207 : * @softirq_next_timer: Pointer to the first expiring softirq based timer
208 : * @clock_base: array of clock bases for this cpu
209 : *
210 : * Note: next_timer is just an optimization for __remove_hrtimer().
211 : * Do not dereference the pointer because it is not reliable on
212 : * cross cpu removals.
213 : */
214 : struct hrtimer_cpu_base {
215 : raw_spinlock_t lock;
216 : unsigned int cpu;
217 : unsigned int active_bases;
218 : unsigned int clock_was_set_seq;
219 : unsigned int hres_active : 1,
220 : in_hrtirq : 1,
221 : hang_detected : 1,
222 : softirq_activated : 1;
223 : #ifdef CONFIG_HIGH_RES_TIMERS
224 : unsigned int nr_events;
225 : unsigned short nr_retries;
226 : unsigned short nr_hangs;
227 : unsigned int max_hang_time;
228 : #endif
229 : #ifdef CONFIG_PREEMPT_RT
230 : spinlock_t softirq_expiry_lock;
231 : atomic_t timer_waiters;
232 : #endif
233 : ktime_t expires_next;
234 : struct hrtimer *next_timer;
235 : ktime_t softirq_expires_next;
236 : struct hrtimer *softirq_next_timer;
237 : struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
238 : } ____cacheline_aligned;
239 :
240 : static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
241 : {
242 0 : timer->node.expires = time;
243 0 : timer->_softexpires = time;
244 : }
245 :
246 : static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
247 : {
248 : timer->_softexpires = time;
249 : timer->node.expires = ktime_add_safe(time, delta);
250 : }
251 :
252 : static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
253 : {
254 0 : timer->_softexpires = time;
255 0 : timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
256 : }
257 :
258 : static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
259 : {
260 0 : timer->node.expires = tv64;
261 0 : timer->_softexpires = tv64;
262 : }
263 :
264 : static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
265 : {
266 0 : timer->node.expires = ktime_add_safe(timer->node.expires, time);
267 0 : timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
268 : }
269 :
270 : static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
271 : {
272 0 : timer->node.expires = ktime_add_ns(timer->node.expires, ns);
273 0 : timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
274 : }
275 :
276 : static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
277 : {
278 : return timer->node.expires;
279 : }
280 :
281 : static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
282 : {
283 : return timer->_softexpires;
284 : }
285 :
286 : static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
287 : {
288 : return timer->node.expires;
289 : }
290 : static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
291 : {
292 : return timer->_softexpires;
293 : }
294 :
295 : static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
296 : {
297 : return ktime_to_ns(timer->node.expires);
298 : }
299 :
300 : static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
301 : {
302 0 : return ktime_sub(timer->node.expires, timer->base->get_time());
303 : }
304 :
305 : static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
306 : {
307 0 : return timer->base->get_time();
308 : }
309 :
310 : static inline int hrtimer_is_hres_active(struct hrtimer *timer)
311 : {
312 : return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
313 : timer->base->cpu_base->hres_active : 0;
314 : }
315 :
316 : #ifdef CONFIG_HIGH_RES_TIMERS
317 : struct clock_event_device;
318 :
319 : extern void hrtimer_interrupt(struct clock_event_device *dev);
320 :
321 : extern unsigned int hrtimer_resolution;
322 :
323 : #else
324 :
325 : #define hrtimer_resolution (unsigned int)LOW_RES_NSEC
326 :
327 : #endif
328 :
329 : static inline ktime_t
330 : __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
331 : {
332 0 : ktime_t rem = ktime_sub(timer->node.expires, now);
333 :
334 : /*
335 : * Adjust relative timers for the extra we added in
336 : * hrtimer_start_range_ns() to prevent short timeouts.
337 : */
338 : if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
339 : rem -= hrtimer_resolution;
340 : return rem;
341 : }
342 :
343 : static inline ktime_t
344 : hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
345 : {
346 0 : return __hrtimer_expires_remaining_adjusted(timer,
347 0 : timer->base->get_time());
348 : }
349 :
350 : #ifdef CONFIG_TIMERFD
351 : extern void timerfd_clock_was_set(void);
352 : extern void timerfd_resume(void);
353 : #else
354 : static inline void timerfd_clock_was_set(void) { }
355 : static inline void timerfd_resume(void) { }
356 : #endif
357 :
358 : DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
359 :
360 : #ifdef CONFIG_PREEMPT_RT
361 : void hrtimer_cancel_wait_running(const struct hrtimer *timer);
362 : #else
363 : static inline void hrtimer_cancel_wait_running(struct hrtimer *timer)
364 : {
365 : cpu_relax();
366 : }
367 : #endif
368 :
369 : /* Exported timer functions: */
370 :
371 : /* Initialize timers: */
372 : extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
373 : enum hrtimer_mode mode);
374 : extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
375 : enum hrtimer_mode mode);
376 :
377 : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
378 : extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
379 : enum hrtimer_mode mode);
380 : extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
381 : clockid_t clock_id,
382 : enum hrtimer_mode mode);
383 :
384 : extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
385 : #else
386 : static inline void hrtimer_init_on_stack(struct hrtimer *timer,
387 : clockid_t which_clock,
388 : enum hrtimer_mode mode)
389 : {
390 0 : hrtimer_init(timer, which_clock, mode);
391 : }
392 :
393 : static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
394 : clockid_t clock_id,
395 : enum hrtimer_mode mode)
396 : {
397 0 : hrtimer_init_sleeper(sl, clock_id, mode);
398 : }
399 :
400 : static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
401 : #endif
402 :
403 : /* Basic timer operations: */
404 : extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
405 : u64 range_ns, const enum hrtimer_mode mode);
406 :
407 : /**
408 : * hrtimer_start - (re)start an hrtimer
409 : * @timer: the timer to be added
410 : * @tim: expiry time
411 : * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
412 : * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
413 : * softirq based mode is considered for debug purpose only!
414 : */
415 : static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
416 : const enum hrtimer_mode mode)
417 : {
418 0 : hrtimer_start_range_ns(timer, tim, 0, mode);
419 : }
420 :
421 : extern int hrtimer_cancel(struct hrtimer *timer);
422 : extern int hrtimer_try_to_cancel(struct hrtimer *timer);
423 :
424 : static inline void hrtimer_start_expires(struct hrtimer *timer,
425 : enum hrtimer_mode mode)
426 : {
427 : u64 delta;
428 : ktime_t soft, hard;
429 0 : soft = hrtimer_get_softexpires(timer);
430 0 : hard = hrtimer_get_expires(timer);
431 0 : delta = ktime_to_ns(ktime_sub(hard, soft));
432 0 : hrtimer_start_range_ns(timer, soft, delta, mode);
433 : }
434 :
435 : void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
436 : enum hrtimer_mode mode);
437 :
438 : static inline void hrtimer_restart(struct hrtimer *timer)
439 : {
440 0 : hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
441 : }
442 :
443 : /* Query timers: */
444 : extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
445 :
446 : /**
447 : * hrtimer_get_remaining - get remaining time for the timer
448 : * @timer: the timer to read
449 : */
450 : static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
451 : {
452 : return __hrtimer_get_remaining(timer, false);
453 : }
454 :
455 : extern u64 hrtimer_get_next_event(void);
456 : extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
457 :
458 : extern bool hrtimer_active(const struct hrtimer *timer);
459 :
460 : /**
461 : * hrtimer_is_queued - check, whether the timer is on one of the queues
462 : * @timer: Timer to check
463 : *
464 : * Returns: True if the timer is queued, false otherwise
465 : *
466 : * The function can be used lockless, but it gives only a current snapshot.
467 : */
468 : static inline bool hrtimer_is_queued(struct hrtimer *timer)
469 : {
470 : /* The READ_ONCE pairs with the update functions of timer->state */
471 0 : return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
472 : }
473 :
474 : /*
475 : * Helper function to check, whether the timer is running the callback
476 : * function
477 : */
478 : static inline int hrtimer_callback_running(struct hrtimer *timer)
479 : {
480 0 : return timer->base->running == timer;
481 : }
482 :
483 : /* Forward a hrtimer so it expires after now: */
484 : extern u64
485 : hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
486 :
487 : /**
488 : * hrtimer_forward_now - forward the timer expiry so it expires after now
489 : * @timer: hrtimer to forward
490 : * @interval: the interval to forward
491 : *
492 : * Forward the timer expiry so it will expire after the current time
493 : * of the hrtimer clock base. Returns the number of overruns.
494 : *
495 : * Can be safely called from the callback function of @timer. If
496 : * called from other contexts @timer must neither be enqueued nor
497 : * running the callback and the caller needs to take care of
498 : * serialization.
499 : *
500 : * Note: This only updates the timer expiry value and does not requeue
501 : * the timer.
502 : */
503 0 : static inline u64 hrtimer_forward_now(struct hrtimer *timer,
504 : ktime_t interval)
505 : {
506 0 : return hrtimer_forward(timer, timer->base->get_time(), interval);
507 : }
508 :
509 : /* Precise sleep: */
510 :
511 : extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
512 : extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
513 : const clockid_t clockid);
514 :
515 : extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
516 : const enum hrtimer_mode mode);
517 : extern int schedule_hrtimeout_range_clock(ktime_t *expires,
518 : u64 delta,
519 : const enum hrtimer_mode mode,
520 : clockid_t clock_id);
521 : extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
522 :
523 : /* Soft interrupt function to run the hrtimer queues: */
524 : extern void hrtimer_run_queues(void);
525 :
526 : /* Bootup initialization: */
527 : extern void __init hrtimers_init(void);
528 :
529 : /* Show pending timers: */
530 : extern void sysrq_timer_list_show(void);
531 :
532 : int hrtimers_prepare_cpu(unsigned int cpu);
533 : #ifdef CONFIG_HOTPLUG_CPU
534 : int hrtimers_dead_cpu(unsigned int cpu);
535 : #else
536 : #define hrtimers_dead_cpu NULL
537 : #endif
538 :
539 : #endif
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