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c0a31329 TG |
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 | ||
3c8aa39d TG |
24 | struct hrtimer_clock_base; |
25 | struct hrtimer_cpu_base; | |
26 | ||
c0a31329 TG |
27 | /* |
28 | * Mode arguments of xxx_hrtimer functions: | |
29 | */ | |
30 | enum hrtimer_mode { | |
c9cb2e3d TG |
31 | HRTIMER_MODE_ABS, /* Time value is absolute */ |
32 | HRTIMER_MODE_REL, /* Time value is relative to now */ | |
c0a31329 TG |
33 | }; |
34 | ||
c9cb2e3d TG |
35 | /* |
36 | * Return values for the callback function | |
37 | */ | |
c0a31329 | 38 | enum hrtimer_restart { |
c9cb2e3d TG |
39 | HRTIMER_NORESTART, /* Timer is not restarted */ |
40 | HRTIMER_RESTART, /* Timer must be restarted */ | |
c0a31329 TG |
41 | }; |
42 | ||
303e967f | 43 | /* |
54cdfdb4 TG |
44 | * hrtimer callback modes: |
45 | * | |
46 | * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context | |
47 | * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context | |
48 | * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and | |
49 | * does not restart the timer | |
ccc7dadf TG |
50 | * HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context |
51 | * Special mode for tick emulation and | |
52 | * scheduler timer. Such timers are per | |
53 | * cpu and not allowed to be migrated on | |
54 | * cpu unplug. | |
55 | * HRTIMER_CB_IRQSAFE_UNLOCKED: Callback should run in hardirq context | |
56 | * with timer->base lock unlocked | |
57 | * used for timers which call wakeup to | |
58 | * avoid lock order problems with rq->lock | |
54cdfdb4 TG |
59 | */ |
60 | enum hrtimer_cb_mode { | |
61 | HRTIMER_CB_SOFTIRQ, | |
62 | HRTIMER_CB_IRQSAFE, | |
63 | HRTIMER_CB_IRQSAFE_NO_RESTART, | |
ccc7dadf TG |
64 | HRTIMER_CB_IRQSAFE_PERCPU, |
65 | HRTIMER_CB_IRQSAFE_UNLOCKED, | |
54cdfdb4 TG |
66 | }; |
67 | ||
68 | /* | |
69 | * Values to track state of the timer | |
303e967f TG |
70 | * |
71 | * Possible states: | |
72 | * | |
73 | * 0x00 inactive | |
74 | * 0x01 enqueued into rbtree | |
75 | * 0x02 callback function running | |
54cdfdb4 TG |
76 | * 0x04 callback pending (high resolution mode) |
77 | * | |
b00c1a99 | 78 | * Special cases: |
303e967f TG |
79 | * 0x03 callback function running and enqueued |
80 | * (was requeued on another CPU) | |
b00c1a99 | 81 | * 0x09 timer was migrated on CPU hotunplug |
303e967f TG |
82 | * The "callback function running and enqueued" status is only possible on |
83 | * SMP. It happens for example when a posix timer expired and the callback | |
84 | * queued a signal. Between dropping the lock which protects the posix timer | |
85 | * and reacquiring the base lock of the hrtimer, another CPU can deliver the | |
86 | * signal and rearm the timer. We have to preserve the callback running state, | |
87 | * as otherwise the timer could be removed before the softirq code finishes the | |
88 | * the handling of the timer. | |
89 | * | |
3eb05676 | 90 | * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to |
303e967f TG |
91 | * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario. |
92 | * | |
93 | * All state transitions are protected by cpu_base->lock. | |
94 | */ | |
95 | #define HRTIMER_STATE_INACTIVE 0x00 | |
96 | #define HRTIMER_STATE_ENQUEUED 0x01 | |
97 | #define HRTIMER_STATE_CALLBACK 0x02 | |
54cdfdb4 | 98 | #define HRTIMER_STATE_PENDING 0x04 |
b00c1a99 | 99 | #define HRTIMER_STATE_MIGRATE 0x08 |
303e967f | 100 | |
c0a31329 TG |
101 | /** |
102 | * struct hrtimer - the basic hrtimer structure | |
c0a31329 | 103 | * @node: red black tree node for time ordered insertion |
c0a31329 TG |
104 | * @expires: the absolute expiry time in the hrtimers internal |
105 | * representation. The time is related to the clock on | |
106 | * which the timer is based. | |
c0a31329 | 107 | * @function: timer expiry callback function |
c0a31329 | 108 | * @base: pointer to the timer base (per cpu and per clock) |
303e967f | 109 | * @state: state information (See bit values above) |
54cdfdb4 TG |
110 | * @cb_mode: high resolution timer feature to select the callback execution |
111 | * mode | |
112 | * @cb_entry: list head to enqueue an expired timer into the callback list | |
113 | * @start_site: timer statistics field to store the site where the timer | |
114 | * was started | |
115 | * @start_comm: timer statistics field to store the name of the process which | |
116 | * started the timer | |
117 | * @start_pid: timer statistics field to store the pid of the task which | |
118 | * started the timer | |
c0a31329 | 119 | * |
54cdfdb4 | 120 | * The hrtimer structure must be initialized by hrtimer_init() |
c0a31329 TG |
121 | */ |
122 | struct hrtimer { | |
3c8aa39d TG |
123 | struct rb_node node; |
124 | ktime_t expires; | |
125 | enum hrtimer_restart (*function)(struct hrtimer *); | |
126 | struct hrtimer_clock_base *base; | |
303e967f | 127 | unsigned long state; |
54cdfdb4 TG |
128 | enum hrtimer_cb_mode cb_mode; |
129 | struct list_head cb_entry; | |
82f67cd9 IM |
130 | #ifdef CONFIG_TIMER_STATS |
131 | void *start_site; | |
132 | char start_comm[16]; | |
133 | int start_pid; | |
134 | #endif | |
c0a31329 TG |
135 | }; |
136 | ||
00362e33 TG |
137 | /** |
138 | * struct hrtimer_sleeper - simple sleeper structure | |
00362e33 TG |
139 | * @timer: embedded timer structure |
140 | * @task: task to wake up | |
141 | * | |
142 | * task is set to NULL, when the timer expires. | |
143 | */ | |
144 | struct hrtimer_sleeper { | |
145 | struct hrtimer timer; | |
146 | struct task_struct *task; | |
147 | }; | |
148 | ||
c0a31329 | 149 | /** |
d1d67174 | 150 | * struct hrtimer_clock_base - the timer base for a specific clock |
05fb6bf0 | 151 | * @cpu_base: per cpu clock base |
3c8aa39d TG |
152 | * @index: clock type index for per_cpu support when moving a |
153 | * timer to a base on another cpu. | |
92127c7a TG |
154 | * @active: red black tree root node for the active timers |
155 | * @first: pointer to the timer node which expires first | |
156 | * @resolution: the resolution of the clock, in nanoseconds | |
157 | * @get_time: function to retrieve the current time of the clock | |
a580290c | 158 | * @get_softirq_time: function to retrieve the current time from the softirq |
92127c7a | 159 | * @softirq_time: the time when running the hrtimer queue in the softirq |
54cdfdb4 TG |
160 | * @offset: offset of this clock to the monotonic base |
161 | * @reprogram: function to reprogram the timer event | |
c0a31329 | 162 | */ |
3c8aa39d TG |
163 | struct hrtimer_clock_base { |
164 | struct hrtimer_cpu_base *cpu_base; | |
c0a31329 | 165 | clockid_t index; |
c0a31329 | 166 | struct rb_root active; |
288867ec | 167 | struct rb_node *first; |
e2787630 | 168 | ktime_t resolution; |
c0a31329 | 169 | ktime_t (*get_time)(void); |
92127c7a | 170 | ktime_t (*get_softirq_time)(void); |
92127c7a | 171 | ktime_t softirq_time; |
54cdfdb4 TG |
172 | #ifdef CONFIG_HIGH_RES_TIMERS |
173 | ktime_t offset; | |
174 | int (*reprogram)(struct hrtimer *t, | |
175 | struct hrtimer_clock_base *b, | |
176 | ktime_t n); | |
177 | #endif | |
3c8aa39d TG |
178 | }; |
179 | ||
180 | #define HRTIMER_MAX_CLOCK_BASES 2 | |
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 | |
3c8aa39d TG |
186 | * @clock_base: array of clock bases for this cpu |
187 | * @curr_timer: the timer which is executing a callback right now | |
54cdfdb4 TG |
188 | * @expires_next: absolute time of the next event which was scheduled |
189 | * via clock_set_next_event() | |
190 | * @hres_active: State of high resolution mode | |
191 | * @check_clocks: Indictator, when set evaluate time source and clock | |
192 | * event devices whether high resolution mode can be | |
193 | * activated. | |
194 | * @cb_pending: Expired timers are moved from the rbtree to this | |
195 | * list in the timer interrupt. The list is processed | |
196 | * in the softirq. | |
197 | * @nr_events: Total number of timer interrupt events | |
3c8aa39d TG |
198 | */ |
199 | struct hrtimer_cpu_base { | |
200 | spinlock_t lock; | |
3c8aa39d | 201 | struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
d3d74453 | 202 | struct list_head cb_pending; |
54cdfdb4 TG |
203 | #ifdef CONFIG_HIGH_RES_TIMERS |
204 | ktime_t expires_next; | |
205 | int hres_active; | |
54cdfdb4 TG |
206 | unsigned long nr_events; |
207 | #endif | |
c0a31329 TG |
208 | }; |
209 | ||
54cdfdb4 TG |
210 | #ifdef CONFIG_HIGH_RES_TIMERS |
211 | struct clock_event_device; | |
212 | ||
213 | extern void clock_was_set(void); | |
995f054f | 214 | extern void hres_timers_resume(void); |
54cdfdb4 TG |
215 | extern void hrtimer_interrupt(struct clock_event_device *dev); |
216 | ||
217 | /* | |
218 | * In high resolution mode the time reference must be read accurate | |
219 | */ | |
220 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) | |
221 | { | |
222 | return timer->base->get_time(); | |
223 | } | |
224 | ||
8f4d37ec PZ |
225 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
226 | { | |
227 | return timer->base->cpu_base->hres_active; | |
228 | } | |
229 | ||
54cdfdb4 TG |
230 | /* |
231 | * The resolution of the clocks. The resolution value is returned in | |
232 | * the clock_getres() system call to give application programmers an | |
233 | * idea of the (in)accuracy of timers. Timer values are rounded up to | |
234 | * this resolution values. | |
235 | */ | |
151db1fc TB |
236 | # define HIGH_RES_NSEC 1 |
237 | # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } | |
238 | # define MONOTONIC_RES_NSEC HIGH_RES_NSEC | |
54cdfdb4 TG |
239 | # define KTIME_MONOTONIC_RES KTIME_HIGH_RES |
240 | ||
241 | #else | |
242 | ||
151db1fc | 243 | # define MONOTONIC_RES_NSEC LOW_RES_NSEC |
54cdfdb4 TG |
244 | # define KTIME_MONOTONIC_RES KTIME_LOW_RES |
245 | ||
becf8b5d TG |
246 | /* |
247 | * clock_was_set() is a NOP for non- high-resolution systems. The | |
248 | * time-sorted order guarantees that a timer does not expire early and | |
249 | * is expired in the next softirq when the clock was advanced. | |
250 | */ | |
54cdfdb4 TG |
251 | static inline void clock_was_set(void) { } |
252 | ||
995f054f IM |
253 | static inline void hres_timers_resume(void) { } |
254 | ||
54cdfdb4 TG |
255 | /* |
256 | * In non high resolution mode the time reference is taken from | |
257 | * the base softirq time variable. | |
258 | */ | |
259 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) | |
260 | { | |
261 | return timer->base->softirq_time; | |
262 | } | |
263 | ||
8f4d37ec PZ |
264 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
265 | { | |
266 | return 0; | |
267 | } | |
54cdfdb4 TG |
268 | #endif |
269 | ||
d316c57f TG |
270 | extern ktime_t ktime_get(void); |
271 | extern ktime_t ktime_get_real(void); | |
becf8b5d | 272 | |
c0a31329 TG |
273 | /* Exported timer functions: */ |
274 | ||
275 | /* Initialize timers: */ | |
7978672c GA |
276 | extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
277 | enum hrtimer_mode mode); | |
c0a31329 | 278 | |
237fc6e7 TG |
279 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
280 | extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, | |
281 | enum hrtimer_mode mode); | |
282 | ||
283 | extern void destroy_hrtimer_on_stack(struct hrtimer *timer); | |
284 | #else | |
285 | static inline void hrtimer_init_on_stack(struct hrtimer *timer, | |
286 | clockid_t which_clock, | |
287 | enum hrtimer_mode mode) | |
288 | { | |
289 | hrtimer_init(timer, which_clock, mode); | |
290 | } | |
291 | static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } | |
292 | #endif | |
293 | ||
c0a31329 TG |
294 | /* Basic timer operations: */ |
295 | extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, | |
296 | const enum hrtimer_mode mode); | |
297 | extern int hrtimer_cancel(struct hrtimer *timer); | |
298 | extern int hrtimer_try_to_cancel(struct hrtimer *timer); | |
299 | ||
c9cb2e3d TG |
300 | static inline int hrtimer_restart(struct hrtimer *timer) |
301 | { | |
302 | return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); | |
303 | } | |
c0a31329 TG |
304 | |
305 | /* Query timers: */ | |
306 | extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); | |
307 | extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); | |
308 | ||
69239749 | 309 | extern ktime_t hrtimer_get_next_event(void); |
69239749 | 310 | |
303e967f TG |
311 | /* |
312 | * A timer is active, when it is enqueued into the rbtree or the callback | |
313 | * function is running. | |
314 | */ | |
c0a31329 TG |
315 | static inline int hrtimer_active(const struct hrtimer *timer) |
316 | { | |
303e967f | 317 | return timer->state != HRTIMER_STATE_INACTIVE; |
c0a31329 TG |
318 | } |
319 | ||
54cdfdb4 TG |
320 | /* |
321 | * Helper function to check, whether the timer is on one of the queues | |
322 | */ | |
323 | static inline int hrtimer_is_queued(struct hrtimer *timer) | |
324 | { | |
325 | return timer->state & | |
326 | (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING); | |
327 | } | |
328 | ||
4346f654 OH |
329 | /* |
330 | * Helper function to check, whether the timer is running the callback | |
331 | * function | |
332 | */ | |
333 | static inline int hrtimer_callback_running(struct hrtimer *timer) | |
334 | { | |
335 | return timer->state & HRTIMER_STATE_CALLBACK; | |
336 | } | |
337 | ||
c0a31329 | 338 | /* Forward a hrtimer so it expires after now: */ |
4d672e7a | 339 | extern u64 |
44f21475 | 340 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
c0a31329 | 341 | |
5e05ad7d | 342 | /* Forward a hrtimer so it expires after the hrtimer's current now */ |
4d672e7a DL |
343 | static inline u64 hrtimer_forward_now(struct hrtimer *timer, |
344 | ktime_t interval) | |
5e05ad7d DL |
345 | { |
346 | return hrtimer_forward(timer, timer->base->get_time(), interval); | |
347 | } | |
348 | ||
10c94ec1 TG |
349 | /* Precise sleep: */ |
350 | extern long hrtimer_nanosleep(struct timespec *rqtp, | |
080344b9 | 351 | struct timespec __user *rmtp, |
10c94ec1 TG |
352 | const enum hrtimer_mode mode, |
353 | const clockid_t clockid); | |
1711ef38 | 354 | extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
10c94ec1 | 355 | |
00362e33 TG |
356 | extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
357 | struct task_struct *tsk); | |
358 | ||
c0a31329 TG |
359 | /* Soft interrupt function to run the hrtimer queues: */ |
360 | extern void hrtimer_run_queues(void); | |
d3d74453 | 361 | extern void hrtimer_run_pending(void); |
c0a31329 TG |
362 | |
363 | /* Bootup initialization: */ | |
364 | extern void __init hrtimers_init(void); | |
365 | ||
79bf2bb3 | 366 | #if BITS_PER_LONG < 64 |
4d672e7a | 367 | extern u64 ktime_divns(const ktime_t kt, s64 div); |
79bf2bb3 | 368 | #else /* BITS_PER_LONG < 64 */ |
4d672e7a | 369 | # define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) |
79bf2bb3 TG |
370 | #endif |
371 | ||
88ad0bf6 IM |
372 | /* Show pending timers: */ |
373 | extern void sysrq_timer_list_show(void); | |
374 | ||
82f67cd9 IM |
375 | /* |
376 | * Timer-statistics info: | |
377 | */ | |
378 | #ifdef CONFIG_TIMER_STATS | |
379 | ||
380 | extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf, | |
c5c061b8 VP |
381 | void *timerf, char *comm, |
382 | unsigned int timer_flag); | |
82f67cd9 IM |
383 | |
384 | static inline void timer_stats_account_hrtimer(struct hrtimer *timer) | |
385 | { | |
386 | timer_stats_update_stats(timer, timer->start_pid, timer->start_site, | |
c5c061b8 | 387 | timer->function, timer->start_comm, 0); |
82f67cd9 IM |
388 | } |
389 | ||
390 | extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, | |
391 | void *addr); | |
392 | ||
393 | static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) | |
394 | { | |
395 | __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0)); | |
396 | } | |
397 | ||
398 | static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) | |
399 | { | |
400 | timer->start_site = NULL; | |
401 | } | |
402 | #else | |
403 | static inline void timer_stats_account_hrtimer(struct hrtimer *timer) | |
404 | { | |
405 | } | |
406 | ||
407 | static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) | |
408 | { | |
409 | } | |
410 | ||
411 | static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) | |
412 | { | |
413 | } | |
414 | #endif | |
415 | ||
c0a31329 | 416 | #endif |