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1 | /* |
2 | * include/linux/hrtimer.h |
3 | * |
4 | * hrtimers - High-resolution kernel timers |
5 | * |
6 | * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> |
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/wait.h> |
23 | #include <linux/percpu.h> |
24 | #include <linux/timer.h> |
25 | |
26 | |
27 | struct hrtimer_clock_base; |
28 | struct hrtimer_cpu_base; |
29 | |
30 | /* |
31 | * Mode arguments of xxx_hrtimer functions: |
32 | */ |
33 | enum hrtimer_mode { |
34 | HRTIMER_MODE_ABS = 0x0, /* Time value is absolute */ |
35 | HRTIMER_MODE_REL = 0x1, /* Time value is relative to now */ |
36 | HRTIMER_MODE_PINNED = 0x02, /* Timer is bound to CPU */ |
37 | HRTIMER_MODE_ABS_PINNED = 0x02, |
38 | HRTIMER_MODE_REL_PINNED = 0x03, |
39 | }; |
40 | |
41 | /* |
42 | * Return values for the callback function |
43 | */ |
44 | enum hrtimer_restart { |
45 | HRTIMER_NORESTART, /* Timer is not restarted */ |
46 | HRTIMER_RESTART, /* Timer must be restarted */ |
47 | }; |
48 | |
49 | /* |
50 | * Values to track state of the timer |
51 | * |
52 | * Possible states: |
53 | * |
54 | * 0x00 inactive |
55 | * 0x01 enqueued into rbtree |
56 | * 0x02 callback function running |
57 | * |
58 | * Special cases: |
59 | * 0x03 callback function running and enqueued |
60 | * (was requeued on another CPU) |
61 | * 0x09 timer was migrated on CPU hotunplug |
62 | * The "callback function running and enqueued" status is only possible on |
63 | * SMP. It happens for example when a posix timer expired and the callback |
64 | * queued a signal. Between dropping the lock which protects the posix timer |
65 | * and reacquiring the base lock of the hrtimer, another CPU can deliver the |
66 | * signal and rearm the timer. We have to preserve the callback running state, |
67 | * as otherwise the timer could be removed before the softirq code finishes the |
68 | * the handling of the timer. |
69 | * |
70 | * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to |
71 | * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario. |
72 | * |
73 | * All state transitions are protected by cpu_base->lock. |
74 | */ |
75 | #define HRTIMER_STATE_INACTIVE 0x00 |
76 | #define HRTIMER_STATE_ENQUEUED 0x01 |
77 | #define HRTIMER_STATE_CALLBACK 0x02 |
78 | #define HRTIMER_STATE_MIGRATE 0x04 |
79 | |
80 | /** |
81 | * struct hrtimer - the basic hrtimer structure |
82 | * @node: red black tree node for time ordered insertion |
83 | * @_expires: the absolute expiry time in the hrtimers internal |
84 | * representation. The time is related to the clock on |
85 | * which the timer is based. Is setup by adding |
86 | * slack to the _softexpires value. For non range timers |
87 | * identical to _softexpires. |
88 | * @_softexpires: the absolute earliest expiry time of the hrtimer. |
89 | * The time which was given as expiry time when the timer |
90 | * was armed. |
91 | * @function: timer expiry callback function |
92 | * @base: pointer to the timer base (per cpu and per clock) |
93 | * @state: state information (See bit values above) |
94 | * @start_site: timer statistics field to store the site where the timer |
95 | * was started |
96 | * @start_comm: timer statistics field to store the name of the process which |
97 | * started the timer |
98 | * @start_pid: timer statistics field to store the pid of the task which |
99 | * started the timer |
100 | * |
101 | * The hrtimer structure must be initialized by hrtimer_init() |
102 | */ |
103 | struct hrtimer { |
104 | struct rb_node node; |
105 | ktime_t _expires; |
106 | ktime_t _softexpires; |
107 | enum hrtimer_restart (*function)(struct hrtimer *); |
108 | struct hrtimer_clock_base *base; |
109 | unsigned long state; |
110 | #ifdef CONFIG_TIMER_STATS |
111 | int start_pid; |
112 | void *start_site; |
113 | char start_comm[16]; |
114 | #endif |
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 | */ |
124 | struct hrtimer_sleeper { |
125 | struct hrtimer timer; |
126 | struct task_struct *task; |
127 | }; |
128 | |
129 | /** |
130 | * struct hrtimer_clock_base - the timer base for a specific clock |
131 | * @cpu_base: per cpu clock base |
132 | * @index: clock type index for per_cpu support when moving a |
133 | * timer to a base on another cpu. |
134 | * @active: red black tree root node for the active timers |
135 | * @first: pointer to the timer node which expires first |
136 | * @resolution: the resolution of the clock, in nanoseconds |
137 | * @get_time: function to retrieve the current time of the clock |
138 | * @softirq_time: the time when running the hrtimer queue in the softirq |
139 | * @offset: offset of this clock to the monotonic base |
140 | */ |
141 | struct hrtimer_clock_base { |
142 | struct hrtimer_cpu_base *cpu_base; |
143 | clockid_t index; |
144 | struct rb_root active; |
145 | struct rb_node *first; |
146 | ktime_t resolution; |
147 | ktime_t (*get_time)(void); |
148 | ktime_t softirq_time; |
149 | #ifdef CONFIG_HIGH_RES_TIMERS |
150 | ktime_t offset; |
151 | #endif |
152 | }; |
153 | |
154 | #define HRTIMER_MAX_CLOCK_BASES 2 |
155 | |
156 | /* |
157 | * struct hrtimer_cpu_base - the per cpu clock bases |
158 | * @lock: lock protecting the base and associated clock bases |
159 | * and timers |
160 | * @clock_base: array of clock bases for this cpu |
161 | * @curr_timer: the timer which is executing a callback right now |
162 | * @expires_next: absolute time of the next event which was scheduled |
163 | * via clock_set_next_event() |
164 | * @hres_active: State of high resolution mode |
165 | * @hang_detected: The last hrtimer interrupt detected a hang |
166 | * @nr_events: Total number of hrtimer interrupt events |
167 | * @nr_retries: Total number of hrtimer interrupt retries |
168 | * @nr_hangs: Total number of hrtimer interrupt hangs |
169 | * @max_hang_time: Maximum time spent in hrtimer_interrupt |
170 | */ |
171 | struct hrtimer_cpu_base { |
172 | raw_spinlock_t lock; |
173 | struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
174 | #ifdef CONFIG_HIGH_RES_TIMERS |
175 | ktime_t expires_next; |
176 | int hres_active; |
177 | int hang_detected; |
178 | unsigned long nr_events; |
179 | unsigned long nr_retries; |
180 | unsigned long nr_hangs; |
181 | ktime_t max_hang_time; |
182 | #endif |
183 | }; |
184 | |
185 | static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) |
186 | { |
187 | timer->_expires = time; |
188 | timer->_softexpires = time; |
189 | } |
190 | |
191 | static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) |
192 | { |
193 | timer->_softexpires = time; |
194 | timer->_expires = ktime_add_safe(time, delta); |
195 | } |
196 | |
197 | static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta) |
198 | { |
199 | timer->_softexpires = time; |
200 | timer->_expires = ktime_add_safe(time, ns_to_ktime(delta)); |
201 | } |
202 | |
203 | static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) |
204 | { |
205 | timer->_expires.tv64 = tv64; |
206 | timer->_softexpires.tv64 = tv64; |
207 | } |
208 | |
209 | static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) |
210 | { |
211 | timer->_expires = ktime_add_safe(timer->_expires, time); |
212 | timer->_softexpires = ktime_add_safe(timer->_softexpires, time); |
213 | } |
214 | |
215 | static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) |
216 | { |
217 | timer->_expires = ktime_add_ns(timer->_expires, ns); |
218 | timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); |
219 | } |
220 | |
221 | static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) |
222 | { |
223 | return timer->_expires; |
224 | } |
225 | |
226 | static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) |
227 | { |
228 | return timer->_softexpires; |
229 | } |
230 | |
231 | static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) |
232 | { |
233 | return timer->_expires.tv64; |
234 | } |
235 | static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) |
236 | { |
237 | return timer->_softexpires.tv64; |
238 | } |
239 | |
240 | static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) |
241 | { |
242 | return ktime_to_ns(timer->_expires); |
243 | } |
244 | |
245 | static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) |
246 | { |
247 | return ktime_sub(timer->_expires, timer->base->get_time()); |
248 | } |
249 | |
250 | #ifdef CONFIG_HIGH_RES_TIMERS |
251 | struct clock_event_device; |
252 | |
253 | extern void clock_was_set(void); |
254 | extern void hres_timers_resume(void); |
255 | extern void hrtimer_interrupt(struct clock_event_device *dev); |
256 | |
257 | /* |
258 | * In high resolution mode the time reference must be read accurate |
259 | */ |
260 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
261 | { |
262 | return timer->base->get_time(); |
263 | } |
264 | |
265 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
266 | { |
267 | return timer->base->cpu_base->hres_active; |
268 | } |
269 | |
270 | extern void hrtimer_peek_ahead_timers(void); |
271 | |
272 | /* |
273 | * The resolution of the clocks. The resolution value is returned in |
274 | * the clock_getres() system call to give application programmers an |
275 | * idea of the (in)accuracy of timers. Timer values are rounded up to |
276 | * this resolution values. |
277 | */ |
278 | # define HIGH_RES_NSEC 1 |
279 | # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } |
280 | # define MONOTONIC_RES_NSEC HIGH_RES_NSEC |
281 | # define KTIME_MONOTONIC_RES KTIME_HIGH_RES |
282 | |
283 | #else |
284 | |
285 | # define MONOTONIC_RES_NSEC LOW_RES_NSEC |
286 | # define KTIME_MONOTONIC_RES KTIME_LOW_RES |
287 | |
288 | /* |
289 | * clock_was_set() is a NOP for non- high-resolution systems. The |
290 | * time-sorted order guarantees that a timer does not expire early and |
291 | * is expired in the next softirq when the clock was advanced. |
292 | */ |
293 | static inline void clock_was_set(void) { } |
294 | static inline void hrtimer_peek_ahead_timers(void) { } |
295 | |
296 | static inline void hres_timers_resume(void) { } |
297 | |
298 | /* |
299 | * In non high resolution mode the time reference is taken from |
300 | * the base softirq time variable. |
301 | */ |
302 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
303 | { |
304 | return timer->base->softirq_time; |
305 | } |
306 | |
307 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
308 | { |
309 | return 0; |
310 | } |
311 | #endif |
312 | |
313 | extern ktime_t ktime_get(void); |
314 | extern ktime_t ktime_get_real(void); |
315 | |
316 | |
317 | DECLARE_PER_CPU(struct tick_device, tick_cpu_device); |
318 | |
319 | |
320 | /* Exported timer functions: */ |
321 | |
322 | /* Initialize timers: */ |
323 | extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
324 | enum hrtimer_mode mode); |
325 | |
326 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
327 | extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, |
328 | enum hrtimer_mode mode); |
329 | |
330 | extern void destroy_hrtimer_on_stack(struct hrtimer *timer); |
331 | #else |
332 | static inline void hrtimer_init_on_stack(struct hrtimer *timer, |
333 | clockid_t which_clock, |
334 | enum hrtimer_mode mode) |
335 | { |
336 | hrtimer_init(timer, which_clock, mode); |
337 | } |
338 | static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } |
339 | #endif |
340 | |
341 | /* Basic timer operations: */ |
342 | extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, |
343 | const enum hrtimer_mode mode); |
344 | extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
345 | unsigned long range_ns, const enum hrtimer_mode mode); |
346 | extern int |
347 | __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
348 | unsigned long delta_ns, |
349 | const enum hrtimer_mode mode, int wakeup); |
350 | |
351 | extern int hrtimer_cancel(struct hrtimer *timer); |
352 | extern int hrtimer_try_to_cancel(struct hrtimer *timer); |
353 | |
354 | static inline int hrtimer_start_expires(struct hrtimer *timer, |
355 | enum hrtimer_mode mode) |
356 | { |
357 | unsigned long delta; |
358 | ktime_t soft, hard; |
359 | soft = hrtimer_get_softexpires(timer); |
360 | hard = hrtimer_get_expires(timer); |
361 | delta = ktime_to_ns(ktime_sub(hard, soft)); |
362 | return hrtimer_start_range_ns(timer, soft, delta, mode); |
363 | } |
364 | |
365 | static inline int hrtimer_restart(struct hrtimer *timer) |
366 | { |
367 | return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); |
368 | } |
369 | |
370 | /* Query timers: */ |
371 | extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); |
372 | extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); |
373 | |
374 | extern ktime_t hrtimer_get_next_event(void); |
375 | |
376 | /* |
377 | * A timer is active, when it is enqueued into the rbtree or the callback |
378 | * function is running. |
379 | */ |
380 | static inline int hrtimer_active(const struct hrtimer *timer) |
381 | { |
382 | return timer->state != HRTIMER_STATE_INACTIVE; |
383 | } |
384 | |
385 | /* |
386 | * Helper function to check, whether the timer is on one of the queues |
387 | */ |
388 | static inline int hrtimer_is_queued(struct hrtimer *timer) |
389 | { |
390 | return timer->state & HRTIMER_STATE_ENQUEUED; |
391 | } |
392 | |
393 | /* |
394 | * Helper function to check, whether the timer is running the callback |
395 | * function |
396 | */ |
397 | static inline int hrtimer_callback_running(struct hrtimer *timer) |
398 | { |
399 | return timer->state & HRTIMER_STATE_CALLBACK; |
400 | } |
401 | |
402 | /* Forward a hrtimer so it expires after now: */ |
403 | extern u64 |
404 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
405 | |
406 | /* Forward a hrtimer so it expires after the hrtimer's current now */ |
407 | static inline u64 hrtimer_forward_now(struct hrtimer *timer, |
408 | ktime_t interval) |
409 | { |
410 | return hrtimer_forward(timer, timer->base->get_time(), interval); |
411 | } |
412 | |
413 | /* Precise sleep: */ |
414 | extern long hrtimer_nanosleep(struct timespec *rqtp, |
415 | struct timespec __user *rmtp, |
416 | const enum hrtimer_mode mode, |
417 | const clockid_t clockid); |
418 | extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
419 | |
420 | extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
421 | struct task_struct *tsk); |
422 | |
423 | extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, |
424 | const enum hrtimer_mode mode); |
425 | extern int schedule_hrtimeout_range_clock(ktime_t *expires, |
426 | unsigned long delta, const enum hrtimer_mode mode, int clock); |
427 | extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); |
428 | |
429 | /* Soft interrupt function to run the hrtimer queues: */ |
430 | extern void hrtimer_run_queues(void); |
431 | extern void hrtimer_run_pending(void); |
432 | |
433 | /* Bootup initialization: */ |
434 | extern void __init hrtimers_init(void); |
435 | |
436 | #if BITS_PER_LONG < 64 |
437 | extern u64 ktime_divns(const ktime_t kt, s64 div); |
438 | #else /* BITS_PER_LONG < 64 */ |
439 | # define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) |
440 | #endif |
441 | |
442 | /* Show pending timers: */ |
443 | extern void sysrq_timer_list_show(void); |
444 | |
445 | #endif |
446 |
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