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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 | #include <linux/timerqueue.h> |
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 | * 0x04 timer is migrated to another cpu |
58 | * |
59 | * Special cases: |
60 | * 0x03 callback function running and enqueued |
61 | * (was requeued on another CPU) |
62 | * 0x05 timer was migrated on CPU hotunplug |
63 | * |
64 | * The "callback function running and enqueued" status is only possible on |
65 | * SMP. It happens for example when a posix timer expired and the callback |
66 | * queued a signal. Between dropping the lock which protects the posix timer |
67 | * and reacquiring the base lock of the hrtimer, another CPU can deliver the |
68 | * signal and rearm the timer. We have to preserve the callback running state, |
69 | * as otherwise the timer could be removed before the softirq code finishes the |
70 | * the handling of the timer. |
71 | * |
72 | * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state |
73 | * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This |
74 | * also affects HRTIMER_STATE_MIGRATE where the preservation is not |
75 | * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is |
76 | * enqueued on the new cpu. |
77 | * |
78 | * All state transitions are protected by cpu_base->lock. |
79 | */ |
80 | #define HRTIMER_STATE_INACTIVE 0x00 |
81 | #define HRTIMER_STATE_ENQUEUED 0x01 |
82 | #define HRTIMER_STATE_CALLBACK 0x02 |
83 | #define HRTIMER_STATE_MIGRATE 0x04 |
84 | |
85 | /** |
86 | * struct hrtimer - the basic hrtimer structure |
87 | * @node: timerqueue node, which also manages node.expires, |
88 | * the absolute expiry time in the hrtimers internal |
89 | * representation. The time is related to the clock on |
90 | * which the timer is based. Is setup by adding |
91 | * slack to the _softexpires value. For non range timers |
92 | * identical to _softexpires. |
93 | * @_softexpires: the absolute earliest expiry time of the hrtimer. |
94 | * The time which was given as expiry time when the timer |
95 | * was armed. |
96 | * @function: timer expiry callback function |
97 | * @base: pointer to the timer base (per cpu and per clock) |
98 | * @state: state information (See bit values above) |
99 | * @start_site: timer statistics field to store the site where the timer |
100 | * was started |
101 | * @start_comm: timer statistics field to store the name of the process which |
102 | * started the timer |
103 | * @start_pid: timer statistics field to store the pid of the task which |
104 | * started the timer |
105 | * |
106 | * The hrtimer structure must be initialized by hrtimer_init() |
107 | */ |
108 | struct hrtimer { |
109 | struct timerqueue_node node; |
110 | ktime_t _softexpires; |
111 | enum hrtimer_restart (*function)(struct hrtimer *); |
112 | struct hrtimer_clock_base *base; |
113 | unsigned long state; |
114 | #ifdef CONFIG_TIMER_STATS |
115 | int start_pid; |
116 | void *start_site; |
117 | char start_comm[16]; |
118 | #endif |
119 | }; |
120 | |
121 | /** |
122 | * struct hrtimer_sleeper - simple sleeper structure |
123 | * @timer: embedded timer structure |
124 | * @task: task to wake up |
125 | * |
126 | * task is set to NULL, when the timer expires. |
127 | */ |
128 | struct hrtimer_sleeper { |
129 | struct hrtimer timer; |
130 | struct task_struct *task; |
131 | }; |
132 | |
133 | /** |
134 | * struct hrtimer_clock_base - the timer base for a specific clock |
135 | * @cpu_base: per cpu clock base |
136 | * @index: clock type index for per_cpu support when moving a |
137 | * timer to a base on another cpu. |
138 | * @clockid: clock id for per_cpu support |
139 | * @active: red black tree root node for the active timers |
140 | * @resolution: the resolution of the clock, in nanoseconds |
141 | * @get_time: function to retrieve the current time of the clock |
142 | * @softirq_time: the time when running the hrtimer queue in the softirq |
143 | * @offset: offset of this clock to the monotonic base |
144 | */ |
145 | struct hrtimer_clock_base { |
146 | struct hrtimer_cpu_base *cpu_base; |
147 | int index; |
148 | clockid_t clockid; |
149 | struct timerqueue_head active; |
150 | ktime_t resolution; |
151 | ktime_t (*get_time)(void); |
152 | ktime_t softirq_time; |
153 | ktime_t offset; |
154 | }; |
155 | |
156 | enum hrtimer_base_type { |
157 | HRTIMER_BASE_MONOTONIC, |
158 | HRTIMER_BASE_REALTIME, |
159 | HRTIMER_BASE_BOOTTIME, |
160 | HRTIMER_MAX_CLOCK_BASES, |
161 | }; |
162 | |
163 | /* |
164 | * struct hrtimer_cpu_base - the per cpu clock bases |
165 | * @lock: lock protecting the base and associated clock bases |
166 | * and timers |
167 | * @active_bases: Bitfield to mark bases with active timers |
168 | * @clock_was_set: Indicates that clock was set from irq context. |
169 | * @expires_next: absolute time of the next event which was scheduled |
170 | * via clock_set_next_event() |
171 | * @hres_active: State of high resolution mode |
172 | * @hang_detected: The last hrtimer interrupt detected a hang |
173 | * @nr_events: Total number of hrtimer interrupt events |
174 | * @nr_retries: Total number of hrtimer interrupt retries |
175 | * @nr_hangs: Total number of hrtimer interrupt hangs |
176 | * @max_hang_time: Maximum time spent in hrtimer_interrupt |
177 | * @clock_base: array of clock bases for this cpu |
178 | */ |
179 | struct hrtimer_cpu_base { |
180 | raw_spinlock_t lock; |
181 | unsigned int active_bases; |
182 | unsigned int clock_was_set; |
183 | #ifdef CONFIG_HIGH_RES_TIMERS |
184 | ktime_t expires_next; |
185 | int hres_active; |
186 | int hang_detected; |
187 | unsigned long nr_events; |
188 | unsigned long nr_retries; |
189 | unsigned long nr_hangs; |
190 | ktime_t max_hang_time; |
191 | #endif |
192 | struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
193 | }; |
194 | |
195 | static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) |
196 | { |
197 | timer->node.expires = time; |
198 | timer->_softexpires = time; |
199 | } |
200 | |
201 | static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) |
202 | { |
203 | timer->_softexpires = time; |
204 | timer->node.expires = ktime_add_safe(time, delta); |
205 | } |
206 | |
207 | static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta) |
208 | { |
209 | timer->_softexpires = time; |
210 | timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); |
211 | } |
212 | |
213 | static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) |
214 | { |
215 | timer->node.expires.tv64 = tv64; |
216 | timer->_softexpires.tv64 = tv64; |
217 | } |
218 | |
219 | static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) |
220 | { |
221 | timer->node.expires = ktime_add_safe(timer->node.expires, time); |
222 | timer->_softexpires = ktime_add_safe(timer->_softexpires, time); |
223 | } |
224 | |
225 | static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) |
226 | { |
227 | timer->node.expires = ktime_add_ns(timer->node.expires, ns); |
228 | timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); |
229 | } |
230 | |
231 | static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) |
232 | { |
233 | return timer->node.expires; |
234 | } |
235 | |
236 | static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) |
237 | { |
238 | return timer->_softexpires; |
239 | } |
240 | |
241 | static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) |
242 | { |
243 | return timer->node.expires.tv64; |
244 | } |
245 | static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) |
246 | { |
247 | return timer->_softexpires.tv64; |
248 | } |
249 | |
250 | static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) |
251 | { |
252 | return ktime_to_ns(timer->node.expires); |
253 | } |
254 | |
255 | static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) |
256 | { |
257 | return ktime_sub(timer->node.expires, timer->base->get_time()); |
258 | } |
259 | |
260 | #ifdef CONFIG_HIGH_RES_TIMERS |
261 | struct clock_event_device; |
262 | |
263 | extern void hrtimer_interrupt(struct clock_event_device *dev); |
264 | |
265 | /* |
266 | * In high resolution mode the time reference must be read accurate |
267 | */ |
268 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
269 | { |
270 | return timer->base->get_time(); |
271 | } |
272 | |
273 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
274 | { |
275 | return timer->base->cpu_base->hres_active; |
276 | } |
277 | |
278 | extern void hrtimer_peek_ahead_timers(void); |
279 | |
280 | /* |
281 | * The resolution of the clocks. The resolution value is returned in |
282 | * the clock_getres() system call to give application programmers an |
283 | * idea of the (in)accuracy of timers. Timer values are rounded up to |
284 | * this resolution values. |
285 | */ |
286 | # define HIGH_RES_NSEC 1 |
287 | # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } |
288 | # define MONOTONIC_RES_NSEC HIGH_RES_NSEC |
289 | # define KTIME_MONOTONIC_RES KTIME_HIGH_RES |
290 | |
291 | extern void clock_was_set_delayed(void); |
292 | |
293 | #else |
294 | |
295 | # define MONOTONIC_RES_NSEC LOW_RES_NSEC |
296 | # define KTIME_MONOTONIC_RES KTIME_LOW_RES |
297 | |
298 | static inline void hrtimer_peek_ahead_timers(void) { } |
299 | |
300 | /* |
301 | * In non high resolution mode the time reference is taken from |
302 | * the base softirq time variable. |
303 | */ |
304 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
305 | { |
306 | return timer->base->softirq_time; |
307 | } |
308 | |
309 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
310 | { |
311 | return 0; |
312 | } |
313 | |
314 | static inline void clock_was_set_delayed(void) { } |
315 | |
316 | #endif |
317 | |
318 | extern void clock_was_set(void); |
319 | #ifdef CONFIG_TIMERFD |
320 | extern void timerfd_clock_was_set(void); |
321 | #else |
322 | static inline void timerfd_clock_was_set(void) { } |
323 | #endif |
324 | extern void hrtimers_resume(void); |
325 | |
326 | extern ktime_t ktime_get(void); |
327 | extern ktime_t ktime_get_real(void); |
328 | extern ktime_t ktime_get_boottime(void); |
329 | extern ktime_t ktime_get_monotonic_offset(void); |
330 | extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot); |
331 | |
332 | DECLARE_PER_CPU(struct tick_device, tick_cpu_device); |
333 | |
334 | |
335 | /* Exported timer functions: */ |
336 | |
337 | /* Initialize timers: */ |
338 | extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
339 | enum hrtimer_mode mode); |
340 | |
341 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
342 | extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, |
343 | enum hrtimer_mode mode); |
344 | |
345 | extern void destroy_hrtimer_on_stack(struct hrtimer *timer); |
346 | #else |
347 | static inline void hrtimer_init_on_stack(struct hrtimer *timer, |
348 | clockid_t which_clock, |
349 | enum hrtimer_mode mode) |
350 | { |
351 | hrtimer_init(timer, which_clock, mode); |
352 | } |
353 | static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } |
354 | #endif |
355 | |
356 | /* Basic timer operations: */ |
357 | extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, |
358 | const enum hrtimer_mode mode); |
359 | extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
360 | unsigned long range_ns, const enum hrtimer_mode mode); |
361 | extern int |
362 | __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
363 | unsigned long delta_ns, |
364 | const enum hrtimer_mode mode, int wakeup); |
365 | |
366 | extern int hrtimer_cancel(struct hrtimer *timer); |
367 | extern int hrtimer_try_to_cancel(struct hrtimer *timer); |
368 | |
369 | static inline int hrtimer_start_expires(struct hrtimer *timer, |
370 | enum hrtimer_mode mode) |
371 | { |
372 | unsigned long delta; |
373 | ktime_t soft, hard; |
374 | soft = hrtimer_get_softexpires(timer); |
375 | hard = hrtimer_get_expires(timer); |
376 | delta = ktime_to_ns(ktime_sub(hard, soft)); |
377 | return hrtimer_start_range_ns(timer, soft, delta, mode); |
378 | } |
379 | |
380 | static inline int hrtimer_restart(struct hrtimer *timer) |
381 | { |
382 | return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); |
383 | } |
384 | |
385 | /* Query timers: */ |
386 | extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); |
387 | extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); |
388 | |
389 | extern ktime_t hrtimer_get_next_event(void); |
390 | |
391 | /* |
392 | * A timer is active, when it is enqueued into the rbtree or the |
393 | * callback function is running or it's in the state of being migrated |
394 | * to another cpu. |
395 | */ |
396 | static inline int hrtimer_active(const struct hrtimer *timer) |
397 | { |
398 | return timer->state != HRTIMER_STATE_INACTIVE; |
399 | } |
400 | |
401 | /* |
402 | * Helper function to check, whether the timer is on one of the queues |
403 | */ |
404 | static inline int hrtimer_is_queued(struct hrtimer *timer) |
405 | { |
406 | return timer->state & HRTIMER_STATE_ENQUEUED; |
407 | } |
408 | |
409 | /* |
410 | * Helper function to check, whether the timer is running the callback |
411 | * function |
412 | */ |
413 | static inline int hrtimer_callback_running(struct hrtimer *timer) |
414 | { |
415 | return timer->state & HRTIMER_STATE_CALLBACK; |
416 | } |
417 | |
418 | /* Forward a hrtimer so it expires after now: */ |
419 | extern u64 |
420 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
421 | |
422 | /* Forward a hrtimer so it expires after the hrtimer's current now */ |
423 | static inline u64 hrtimer_forward_now(struct hrtimer *timer, |
424 | ktime_t interval) |
425 | { |
426 | return hrtimer_forward(timer, timer->base->get_time(), interval); |
427 | } |
428 | |
429 | /* Precise sleep: */ |
430 | extern long hrtimer_nanosleep(struct timespec *rqtp, |
431 | struct timespec __user *rmtp, |
432 | const enum hrtimer_mode mode, |
433 | const clockid_t clockid); |
434 | extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
435 | |
436 | extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
437 | struct task_struct *tsk); |
438 | |
439 | extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, |
440 | const enum hrtimer_mode mode); |
441 | extern int schedule_hrtimeout_range_clock(ktime_t *expires, |
442 | unsigned long delta, const enum hrtimer_mode mode, int clock); |
443 | extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); |
444 | |
445 | /* Soft interrupt function to run the hrtimer queues: */ |
446 | extern void hrtimer_run_queues(void); |
447 | extern void hrtimer_run_pending(void); |
448 | |
449 | /* Bootup initialization: */ |
450 | extern void __init hrtimers_init(void); |
451 | |
452 | #if BITS_PER_LONG < 64 |
453 | extern u64 ktime_divns(const ktime_t kt, s64 div); |
454 | #else /* BITS_PER_LONG < 64 */ |
455 | # define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) |
456 | #endif |
457 | |
458 | /* Show pending timers: */ |
459 | extern void sysrq_timer_list_show(void); |
460 | |
461 | #endif |
462 |
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