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 * @online: CPU is online from an hrtimers point of view
201 * @timer_waiters: A hrtimer_cancel() invocation waits for the timer
202 * callback to finish.
203 * @expires_next: absolute time of the next event, is required for remote
204 * hrtimer enqueue; it is the total first expiry time (hard
205 * and soft hrtimer are taken into account)
206 * @next_timer: Pointer to the first expiring timer
207 * @softirq_expires_next: Time to check, if soft queues needs also to be expired
208 * @softirq_next_timer: Pointer to the first expiring softirq based timer
209 * @clock_base: array of clock bases for this cpu
210 *
211 * Note: next_timer is just an optimization for __remove_hrtimer().
212 * Do not dereference the pointer because it is not reliable on
213 * cross cpu removals.
214 */
215 struct hrtimer_cpu_base {
216 raw_spinlock_t lock;
217 unsigned int cpu;
218 unsigned int active_bases;
219 unsigned int clock_was_set_seq;
220 unsigned int hres_active : 1,
221 in_hrtirq : 1,
222 hang_detected : 1,
223 softirq_activated : 1,
224 online : 1;
225 #ifdef CONFIG_HIGH_RES_TIMERS
226 unsigned int nr_events;
227 unsigned short nr_retries;
228 unsigned short nr_hangs;
229 unsigned int max_hang_time;
230 #endif
231 #ifdef CONFIG_PREEMPT_RT
232 spinlock_t softirq_expiry_lock;
233 atomic_t timer_waiters;
234 #endif
235 ktime_t expires_next;
236 struct hrtimer *next_timer;
237 ktime_t softirq_expires_next;
238 struct hrtimer *softirq_next_timer;
239 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
240 } ____cacheline_aligned;
241
hrtimer_set_expires(struct hrtimer * timer,ktime_t time)242 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
243 {
244 timer->node.expires = time;
245 timer->_softexpires = time;
246 }
247
hrtimer_set_expires_range(struct hrtimer * timer,ktime_t time,ktime_t delta)248 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
249 {
250 timer->_softexpires = time;
251 timer->node.expires = ktime_add_safe(time, delta);
252 }
253
hrtimer_set_expires_range_ns(struct hrtimer * timer,ktime_t time,u64 delta)254 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta)
255 {
256 timer->_softexpires = time;
257 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
258 }
259
hrtimer_set_expires_tv64(struct hrtimer * timer,s64 tv64)260 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
261 {
262 timer->node.expires = tv64;
263 timer->_softexpires = tv64;
264 }
265
hrtimer_add_expires(struct hrtimer * timer,ktime_t time)266 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
267 {
268 timer->node.expires = ktime_add_safe(timer->node.expires, time);
269 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
270 }
271
hrtimer_add_expires_ns(struct hrtimer * timer,u64 ns)272 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
273 {
274 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
275 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
276 }
277
hrtimer_get_expires(const struct hrtimer * timer)278 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
279 {
280 return timer->node.expires;
281 }
282
hrtimer_get_softexpires(const struct hrtimer * timer)283 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
284 {
285 return timer->_softexpires;
286 }
287
hrtimer_get_expires_tv64(const struct hrtimer * timer)288 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
289 {
290 return timer->node.expires;
291 }
hrtimer_get_softexpires_tv64(const struct hrtimer * timer)292 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
293 {
294 return timer->_softexpires;
295 }
296
hrtimer_get_expires_ns(const struct hrtimer * timer)297 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
298 {
299 return ktime_to_ns(timer->node.expires);
300 }
301
hrtimer_expires_remaining(const struct hrtimer * timer)302 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
303 {
304 return ktime_sub(timer->node.expires, timer->base->get_time());
305 }
306
hrtimer_cb_get_time(struct hrtimer * timer)307 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
308 {
309 return timer->base->get_time();
310 }
311
hrtimer_is_hres_active(struct hrtimer * timer)312 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
313 {
314 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
315 timer->base->cpu_base->hres_active : 0;
316 }
317
318 #ifdef CONFIG_HIGH_RES_TIMERS
319 struct clock_event_device;
320
321 extern void hrtimer_interrupt(struct clock_event_device *dev);
322
323 extern unsigned int hrtimer_resolution;
324
325 #else
326
327 #define hrtimer_resolution (unsigned int)LOW_RES_NSEC
328
329 #endif
330
331 static inline ktime_t
__hrtimer_expires_remaining_adjusted(const struct hrtimer * timer,ktime_t now)332 __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
333 {
334 ktime_t rem = ktime_sub(timer->node.expires, now);
335
336 /*
337 * Adjust relative timers for the extra we added in
338 * hrtimer_start_range_ns() to prevent short timeouts.
339 */
340 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel)
341 rem -= hrtimer_resolution;
342 return rem;
343 }
344
345 static inline ktime_t
hrtimer_expires_remaining_adjusted(const struct hrtimer * timer)346 hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
347 {
348 return __hrtimer_expires_remaining_adjusted(timer,
349 timer->base->get_time());
350 }
351
352 #ifdef CONFIG_TIMERFD
353 extern void timerfd_clock_was_set(void);
354 extern void timerfd_resume(void);
355 #else
timerfd_clock_was_set(void)356 static inline void timerfd_clock_was_set(void) { }
timerfd_resume(void)357 static inline void timerfd_resume(void) { }
358 #endif
359
360 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
361
362 #ifdef CONFIG_PREEMPT_RT
363 void hrtimer_cancel_wait_running(const struct hrtimer *timer);
364 #else
hrtimer_cancel_wait_running(struct hrtimer * timer)365 static inline void hrtimer_cancel_wait_running(struct hrtimer *timer)
366 {
367 cpu_relax();
368 }
369 #endif
370
371 /* Exported timer functions: */
372
373 /* Initialize timers: */
374 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
375 enum hrtimer_mode mode);
376 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
377 enum hrtimer_mode mode);
378
379 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
380 extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
381 enum hrtimer_mode mode);
382 extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
383 clockid_t clock_id,
384 enum hrtimer_mode mode);
385
386 extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
387 #else
hrtimer_init_on_stack(struct hrtimer * timer,clockid_t which_clock,enum hrtimer_mode mode)388 static inline void hrtimer_init_on_stack(struct hrtimer *timer,
389 clockid_t which_clock,
390 enum hrtimer_mode mode)
391 {
392 hrtimer_init(timer, which_clock, mode);
393 }
394
hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper * sl,clockid_t clock_id,enum hrtimer_mode mode)395 static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
396 clockid_t clock_id,
397 enum hrtimer_mode mode)
398 {
399 hrtimer_init_sleeper(sl, clock_id, mode);
400 }
401
destroy_hrtimer_on_stack(struct hrtimer * timer)402 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
403 #endif
404
405 /* Basic timer operations: */
406 extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
407 u64 range_ns, const enum hrtimer_mode mode);
408
409 /**
410 * hrtimer_start - (re)start an hrtimer
411 * @timer: the timer to be added
412 * @tim: expiry time
413 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or
414 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
415 * softirq based mode is considered for debug purpose only!
416 */
hrtimer_start(struct hrtimer * timer,ktime_t tim,const enum hrtimer_mode mode)417 static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
418 const enum hrtimer_mode mode)
419 {
420 hrtimer_start_range_ns(timer, tim, 0, mode);
421 }
422
423 extern int hrtimer_cancel(struct hrtimer *timer);
424 extern int hrtimer_try_to_cancel(struct hrtimer *timer);
425
hrtimer_start_expires(struct hrtimer * timer,enum hrtimer_mode mode)426 static inline void hrtimer_start_expires(struct hrtimer *timer,
427 enum hrtimer_mode mode)
428 {
429 u64 delta;
430 ktime_t soft, hard;
431 soft = hrtimer_get_softexpires(timer);
432 hard = hrtimer_get_expires(timer);
433 delta = ktime_to_ns(ktime_sub(hard, soft));
434 hrtimer_start_range_ns(timer, soft, delta, mode);
435 }
436
437 void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
438 enum hrtimer_mode mode);
439
hrtimer_restart(struct hrtimer * timer)440 static inline void hrtimer_restart(struct hrtimer *timer)
441 {
442 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
443 }
444
445 /* Query timers: */
446 extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
447
448 /**
449 * hrtimer_get_remaining - get remaining time for the timer
450 * @timer: the timer to read
451 */
hrtimer_get_remaining(const struct hrtimer * timer)452 static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
453 {
454 return __hrtimer_get_remaining(timer, false);
455 }
456
457 extern u64 hrtimer_get_next_event(void);
458 extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
459
460 extern bool hrtimer_active(const struct hrtimer *timer);
461
462 /**
463 * hrtimer_is_queued - check, whether the timer is on one of the queues
464 * @timer: Timer to check
465 *
466 * Returns: True if the timer is queued, false otherwise
467 *
468 * The function can be used lockless, but it gives only a current snapshot.
469 */
hrtimer_is_queued(struct hrtimer * timer)470 static inline bool hrtimer_is_queued(struct hrtimer *timer)
471 {
472 /* The READ_ONCE pairs with the update functions of timer->state */
473 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED);
474 }
475
476 /*
477 * Helper function to check, whether the timer is running the callback
478 * function
479 */
hrtimer_callback_running(struct hrtimer * timer)480 static inline int hrtimer_callback_running(struct hrtimer *timer)
481 {
482 return timer->base->running == timer;
483 }
484
485 /* Forward a hrtimer so it expires after now: */
486 extern u64
487 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
488
489 /**
490 * hrtimer_forward_now - forward the timer expiry so it expires after now
491 * @timer: hrtimer to forward
492 * @interval: the interval to forward
493 *
494 * Forward the timer expiry so it will expire after the current time
495 * of the hrtimer clock base. Returns the number of overruns.
496 *
497 * Can be safely called from the callback function of @timer. If
498 * called from other contexts @timer must neither be enqueued nor
499 * running the callback and the caller needs to take care of
500 * serialization.
501 *
502 * Note: This only updates the timer expiry value and does not requeue
503 * the timer.
504 */
hrtimer_forward_now(struct hrtimer * timer,ktime_t interval)505 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
506 ktime_t interval)
507 {
508 return hrtimer_forward(timer, timer->base->get_time(), interval);
509 }
510
511 /* Precise sleep: */
512
513 extern int nanosleep_copyout(struct restart_block *, struct timespec64 *);
514 extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
515 const clockid_t clockid);
516
517 extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta,
518 const enum hrtimer_mode mode);
519 extern int schedule_hrtimeout_range_clock(ktime_t *expires,
520 u64 delta,
521 const enum hrtimer_mode mode,
522 clockid_t clock_id);
523 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
524
525 /* Soft interrupt function to run the hrtimer queues: */
526 extern void hrtimer_run_queues(void);
527
528 /* Bootup initialization: */
529 extern void __init hrtimers_init(void);
530
531 /* Show pending timers: */
532 extern void sysrq_timer_list_show(void);
533
534 int hrtimers_prepare_cpu(unsigned int cpu);
535 #ifdef CONFIG_HOTPLUG_CPU
536 int hrtimers_cpu_dying(unsigned int cpu);
537 #else
538 #define hrtimers_cpu_dying NULL
539 #endif
540
541 #endif
542