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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 | |
50 | * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in softirq context | |
51 | * Special mode for tick emultation | |
52 | */ | |
53 | enum hrtimer_cb_mode { | |
54 | HRTIMER_CB_SOFTIRQ, | |
55 | HRTIMER_CB_IRQSAFE, | |
56 | HRTIMER_CB_IRQSAFE_NO_RESTART, | |
57 | HRTIMER_CB_IRQSAFE_NO_SOFTIRQ, | |
58 | }; | |
59 | ||
60 | /* | |
61 | * Values to track state of the timer | |
303e967f TG |
62 | * |
63 | * Possible states: | |
64 | * | |
65 | * 0x00 inactive | |
66 | * 0x01 enqueued into rbtree | |
67 | * 0x02 callback function running | |
54cdfdb4 TG |
68 | * 0x04 callback pending (high resolution mode) |
69 | * | |
70 | * Special case: | |
303e967f TG |
71 | * 0x03 callback function running and enqueued |
72 | * (was requeued on another CPU) | |
303e967f TG |
73 | * The "callback function running and enqueued" status is only possible on |
74 | * SMP. It happens for example when a posix timer expired and the callback | |
75 | * queued a signal. Between dropping the lock which protects the posix timer | |
76 | * and reacquiring the base lock of the hrtimer, another CPU can deliver the | |
77 | * signal and rearm the timer. We have to preserve the callback running state, | |
78 | * as otherwise the timer could be removed before the softirq code finishes the | |
79 | * the handling of the timer. | |
80 | * | |
81 | * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to | |
82 | * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario. | |
83 | * | |
84 | * All state transitions are protected by cpu_base->lock. | |
85 | */ | |
86 | #define HRTIMER_STATE_INACTIVE 0x00 | |
87 | #define HRTIMER_STATE_ENQUEUED 0x01 | |
88 | #define HRTIMER_STATE_CALLBACK 0x02 | |
54cdfdb4 | 89 | #define HRTIMER_STATE_PENDING 0x04 |
303e967f | 90 | |
c0a31329 TG |
91 | /** |
92 | * struct hrtimer - the basic hrtimer structure | |
c0a31329 | 93 | * @node: red black tree node for time ordered insertion |
c0a31329 TG |
94 | * @expires: the absolute expiry time in the hrtimers internal |
95 | * representation. The time is related to the clock on | |
96 | * which the timer is based. | |
c0a31329 | 97 | * @function: timer expiry callback function |
c0a31329 | 98 | * @base: pointer to the timer base (per cpu and per clock) |
303e967f | 99 | * @state: state information (See bit values above) |
54cdfdb4 TG |
100 | * @cb_mode: high resolution timer feature to select the callback execution |
101 | * mode | |
102 | * @cb_entry: list head to enqueue an expired timer into the callback list | |
103 | * @start_site: timer statistics field to store the site where the timer | |
104 | * was started | |
105 | * @start_comm: timer statistics field to store the name of the process which | |
106 | * started the timer | |
107 | * @start_pid: timer statistics field to store the pid of the task which | |
108 | * started the timer | |
c0a31329 | 109 | * |
54cdfdb4 | 110 | * The hrtimer structure must be initialized by hrtimer_init() |
c0a31329 TG |
111 | */ |
112 | struct hrtimer { | |
3c8aa39d TG |
113 | struct rb_node node; |
114 | ktime_t expires; | |
115 | enum hrtimer_restart (*function)(struct hrtimer *); | |
116 | struct hrtimer_clock_base *base; | |
303e967f | 117 | unsigned long state; |
54cdfdb4 TG |
118 | #ifdef CONFIG_HIGH_RES_TIMERS |
119 | enum hrtimer_cb_mode cb_mode; | |
120 | struct list_head cb_entry; | |
121 | #endif | |
82f67cd9 IM |
122 | #ifdef CONFIG_TIMER_STATS |
123 | void *start_site; | |
124 | char start_comm[16]; | |
125 | int start_pid; | |
126 | #endif | |
c0a31329 TG |
127 | }; |
128 | ||
00362e33 TG |
129 | /** |
130 | * struct hrtimer_sleeper - simple sleeper structure | |
00362e33 TG |
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 | ||
c0a31329 TG |
141 | /** |
142 | * struct hrtimer_base - the timer base for a specific clock | |
3c8aa39d TG |
143 | * @index: clock type index for per_cpu support when moving a |
144 | * timer to a base on another cpu. | |
92127c7a TG |
145 | * @active: red black tree root node for the active timers |
146 | * @first: pointer to the timer node which expires first | |
147 | * @resolution: the resolution of the clock, in nanoseconds | |
148 | * @get_time: function to retrieve the current time of the clock | |
a580290c | 149 | * @get_softirq_time: function to retrieve the current time from the softirq |
92127c7a | 150 | * @softirq_time: the time when running the hrtimer queue in the softirq |
54cdfdb4 TG |
151 | * @cb_pending: list of timers where the callback is pending |
152 | * @offset: offset of this clock to the monotonic base | |
153 | * @reprogram: function to reprogram the timer event | |
c0a31329 | 154 | */ |
3c8aa39d TG |
155 | struct hrtimer_clock_base { |
156 | struct hrtimer_cpu_base *cpu_base; | |
c0a31329 | 157 | clockid_t index; |
c0a31329 | 158 | struct rb_root active; |
288867ec | 159 | struct rb_node *first; |
e2787630 | 160 | ktime_t resolution; |
c0a31329 | 161 | ktime_t (*get_time)(void); |
92127c7a | 162 | ktime_t (*get_softirq_time)(void); |
92127c7a | 163 | ktime_t softirq_time; |
54cdfdb4 TG |
164 | #ifdef CONFIG_HIGH_RES_TIMERS |
165 | ktime_t offset; | |
166 | int (*reprogram)(struct hrtimer *t, | |
167 | struct hrtimer_clock_base *b, | |
168 | ktime_t n); | |
169 | #endif | |
3c8aa39d TG |
170 | }; |
171 | ||
172 | #define HRTIMER_MAX_CLOCK_BASES 2 | |
173 | ||
174 | /* | |
175 | * struct hrtimer_cpu_base - the per cpu clock bases | |
176 | * @lock: lock protecting the base and associated clock bases | |
177 | * and timers | |
178 | * @lock_key: the lock_class_key for use with lockdep | |
179 | * @clock_base: array of clock bases for this cpu | |
180 | * @curr_timer: the timer which is executing a callback right now | |
54cdfdb4 TG |
181 | * @expires_next: absolute time of the next event which was scheduled |
182 | * via clock_set_next_event() | |
183 | * @hres_active: State of high resolution mode | |
184 | * @check_clocks: Indictator, when set evaluate time source and clock | |
185 | * event devices whether high resolution mode can be | |
186 | * activated. | |
187 | * @cb_pending: Expired timers are moved from the rbtree to this | |
188 | * list in the timer interrupt. The list is processed | |
189 | * in the softirq. | |
190 | * @nr_events: Total number of timer interrupt events | |
3c8aa39d TG |
191 | */ |
192 | struct hrtimer_cpu_base { | |
193 | spinlock_t lock; | |
194 | struct lock_class_key lock_key; | |
195 | struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; | |
54cdfdb4 TG |
196 | #ifdef CONFIG_HIGH_RES_TIMERS |
197 | ktime_t expires_next; | |
198 | int hres_active; | |
199 | struct list_head cb_pending; | |
200 | unsigned long nr_events; | |
201 | #endif | |
c0a31329 TG |
202 | }; |
203 | ||
54cdfdb4 TG |
204 | #ifdef CONFIG_HIGH_RES_TIMERS |
205 | struct clock_event_device; | |
206 | ||
207 | extern void clock_was_set(void); | |
208 | extern void hrtimer_interrupt(struct clock_event_device *dev); | |
209 | ||
210 | /* | |
211 | * In high resolution mode the time reference must be read accurate | |
212 | */ | |
213 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) | |
214 | { | |
215 | return timer->base->get_time(); | |
216 | } | |
217 | ||
218 | /* | |
219 | * The resolution of the clocks. The resolution value is returned in | |
220 | * the clock_getres() system call to give application programmers an | |
221 | * idea of the (in)accuracy of timers. Timer values are rounded up to | |
222 | * this resolution values. | |
223 | */ | |
224 | # define KTIME_HIGH_RES (ktime_t) { .tv64 = 1 } | |
225 | # define KTIME_MONOTONIC_RES KTIME_HIGH_RES | |
226 | ||
227 | #else | |
228 | ||
229 | # define KTIME_MONOTONIC_RES KTIME_LOW_RES | |
230 | ||
becf8b5d TG |
231 | /* |
232 | * clock_was_set() is a NOP for non- high-resolution systems. The | |
233 | * time-sorted order guarantees that a timer does not expire early and | |
234 | * is expired in the next softirq when the clock was advanced. | |
235 | */ | |
54cdfdb4 TG |
236 | static inline void clock_was_set(void) { } |
237 | ||
238 | /* | |
239 | * In non high resolution mode the time reference is taken from | |
240 | * the base softirq time variable. | |
241 | */ | |
242 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) | |
243 | { | |
244 | return timer->base->softirq_time; | |
245 | } | |
246 | ||
247 | #endif | |
248 | ||
d316c57f TG |
249 | extern ktime_t ktime_get(void); |
250 | extern ktime_t ktime_get_real(void); | |
becf8b5d | 251 | |
c0a31329 TG |
252 | /* Exported timer functions: */ |
253 | ||
254 | /* Initialize timers: */ | |
7978672c GA |
255 | extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
256 | enum hrtimer_mode mode); | |
c0a31329 TG |
257 | |
258 | /* Basic timer operations: */ | |
259 | extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, | |
260 | const enum hrtimer_mode mode); | |
261 | extern int hrtimer_cancel(struct hrtimer *timer); | |
262 | extern int hrtimer_try_to_cancel(struct hrtimer *timer); | |
263 | ||
c9cb2e3d TG |
264 | static inline int hrtimer_restart(struct hrtimer *timer) |
265 | { | |
266 | return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); | |
267 | } | |
c0a31329 TG |
268 | |
269 | /* Query timers: */ | |
270 | extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); | |
271 | extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); | |
272 | ||
69239749 | 273 | extern ktime_t hrtimer_get_next_event(void); |
69239749 | 274 | |
303e967f TG |
275 | /* |
276 | * A timer is active, when it is enqueued into the rbtree or the callback | |
277 | * function is running. | |
278 | */ | |
c0a31329 TG |
279 | static inline int hrtimer_active(const struct hrtimer *timer) |
280 | { | |
303e967f | 281 | return timer->state != HRTIMER_STATE_INACTIVE; |
c0a31329 TG |
282 | } |
283 | ||
54cdfdb4 TG |
284 | /* |
285 | * Helper function to check, whether the timer is on one of the queues | |
286 | */ | |
287 | static inline int hrtimer_is_queued(struct hrtimer *timer) | |
288 | { | |
289 | return timer->state & | |
290 | (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING); | |
291 | } | |
292 | ||
c0a31329 | 293 | /* Forward a hrtimer so it expires after now: */ |
44f21475 RZ |
294 | extern unsigned long |
295 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); | |
c0a31329 | 296 | |
10c94ec1 TG |
297 | /* Precise sleep: */ |
298 | extern long hrtimer_nanosleep(struct timespec *rqtp, | |
299 | struct timespec __user *rmtp, | |
300 | const enum hrtimer_mode mode, | |
301 | const clockid_t clockid); | |
1711ef38 | 302 | extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
10c94ec1 | 303 | |
00362e33 TG |
304 | extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
305 | struct task_struct *tsk); | |
306 | ||
c0a31329 TG |
307 | /* Soft interrupt function to run the hrtimer queues: */ |
308 | extern void hrtimer_run_queues(void); | |
309 | ||
310 | /* Bootup initialization: */ | |
311 | extern void __init hrtimers_init(void); | |
312 | ||
79bf2bb3 TG |
313 | #if BITS_PER_LONG < 64 |
314 | extern unsigned long ktime_divns(const ktime_t kt, s64 div); | |
315 | #else /* BITS_PER_LONG < 64 */ | |
316 | # define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) | |
317 | #endif | |
318 | ||
88ad0bf6 IM |
319 | /* Show pending timers: */ |
320 | extern void sysrq_timer_list_show(void); | |
321 | ||
82f67cd9 IM |
322 | /* |
323 | * Timer-statistics info: | |
324 | */ | |
325 | #ifdef CONFIG_TIMER_STATS | |
326 | ||
327 | extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf, | |
328 | void *timerf, char * comm); | |
329 | ||
330 | static inline void timer_stats_account_hrtimer(struct hrtimer *timer) | |
331 | { | |
332 | timer_stats_update_stats(timer, timer->start_pid, timer->start_site, | |
333 | timer->function, timer->start_comm); | |
334 | } | |
335 | ||
336 | extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, | |
337 | void *addr); | |
338 | ||
339 | static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) | |
340 | { | |
341 | __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0)); | |
342 | } | |
343 | ||
344 | static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) | |
345 | { | |
346 | timer->start_site = NULL; | |
347 | } | |
348 | #else | |
349 | static inline void timer_stats_account_hrtimer(struct hrtimer *timer) | |
350 | { | |
351 | } | |
352 | ||
353 | static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) | |
354 | { | |
355 | } | |
356 | ||
357 | static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) | |
358 | { | |
359 | } | |
360 | #endif | |
361 | ||
c0a31329 | 362 | #endif |