Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
/*
 *  include/linux/hrtimer.h
 *
 *  hrtimers - High-resolution kernel timers
 *
 *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
 *
 *  data type definitions, declarations, prototypes
 *
 *  Started by: Thomas Gleixner and Ingo Molnar
 *
 *  For licencing details see kernel-base/COPYING
 */
#ifndef _LINUX_HRTIMER_H
#define _LINUX_HRTIMER_H

#include <linux/rbtree.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/percpu.h>
#include <linux/timer.h>
#include <linux/timerqueue.h>

struct hrtimer_clock_base;
struct hrtimer_cpu_base;

/*
 * Mode arguments of xxx_hrtimer functions:
 */
enum hrtimer_mode {
	HRTIMER_MODE_ABS = 0x0,		/* Time value is absolute */
	HRTIMER_MODE_REL = 0x1,		/* Time value is relative to now */
	HRTIMER_MODE_PINNED = 0x02,	/* Timer is bound to CPU */
	HRTIMER_MODE_ABS_PINNED = 0x02,
	HRTIMER_MODE_REL_PINNED = 0x03,
};

/*
 * Return values for the callback function
 */
enum hrtimer_restart {
	HRTIMER_NORESTART,	/* Timer is not restarted */
	HRTIMER_RESTART,	/* Timer must be restarted */
};

/*
 * Values to track state of the timer
 *
 * Possible states:
 *
 * 0x00		inactive
 * 0x01		enqueued into rbtree
 * 0x02		callback function running
 * 0x04		timer is migrated to another cpu
 *
 * Special cases:
 * 0x03		callback function running and enqueued
 *		(was requeued on another CPU)
 * 0x05		timer was migrated on CPU hotunplug
 *
 * The "callback function running and enqueued" status is only possible on
 * SMP. It happens for example when a posix timer expired and the callback
 * queued a signal. Between dropping the lock which protects the posix timer
 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
 * signal and rearm the timer. We have to preserve the callback running state,
 * as otherwise the timer could be removed before the softirq code finishes the
 * the handling of the timer.
 *
 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state
 * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This
 * also affects HRTIMER_STATE_MIGRATE where the preservation is not
 * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is
 * enqueued on the new cpu.
 *
 * All state transitions are protected by cpu_base->lock.
 */
#define HRTIMER_STATE_INACTIVE	0x00
#define HRTIMER_STATE_ENQUEUED	0x01
#define HRTIMER_STATE_CALLBACK	0x02
#define HRTIMER_STATE_MIGRATE	0x04

/**
 * struct hrtimer - the basic hrtimer structure
 * @node:	timerqueue node, which also manages node.expires,
 *		the absolute expiry time in the hrtimers internal
 *		representation. The time is related to the clock on
 *		which the timer is based. Is setup by adding
 *		slack to the _softexpires value. For non range timers
 *		identical to _softexpires.
 * @_softexpires: the absolute earliest expiry time of the hrtimer.
 *		The time which was given as expiry time when the timer
 *		was armed.
 * @function:	timer expiry callback function
 * @base:	pointer to the timer base (per cpu and per clock)
 * @state:	state information (See bit values above)
 * @start_pid: timer statistics field to store the pid of the task which
 *		started the timer
 * @start_site:	timer statistics field to store the site where the timer
 *		was started
 * @start_comm: timer statistics field to store the name of the process which
 *		started the timer
 *
 * The hrtimer structure must be initialized by hrtimer_init()
 */
struct hrtimer {
	struct timerqueue_node		node;
	ktime_t				_softexpires;
	enum hrtimer_restart		(*function)(struct hrtimer *);
	struct hrtimer_clock_base	*base;
	unsigned long			state;
#ifdef CONFIG_TIMER_STATS
	int				start_pid;
	void				*start_site;
	char				start_comm[16];
#endif
};

/**
 * struct hrtimer_sleeper - simple sleeper structure
 * @timer:	embedded timer structure
 * @task:	task to wake up
 *
 * task is set to NULL, when the timer expires.
 */
struct hrtimer_sleeper {
	struct hrtimer timer;
	struct task_struct *task;
};

/**
 * struct hrtimer_clock_base - the timer base for a specific clock
 * @cpu_base:		per cpu clock base
 * @index:		clock type index for per_cpu support when moving a
 *			timer to a base on another cpu.
 * @clockid:		clock id for per_cpu support
 * @active:		red black tree root node for the active timers
 * @resolution:		the resolution of the clock, in nanoseconds
 * @get_time:		function to retrieve the current time of the clock
 * @softirq_time:	the time when running the hrtimer queue in the softirq
 * @offset:		offset of this clock to the monotonic base
 */
struct hrtimer_clock_base {
	struct hrtimer_cpu_base	*cpu_base;
	int			index;
	clockid_t		clockid;
	struct timerqueue_head	active;
	ktime_t			resolution;
	ktime_t			(*get_time)(void);
	ktime_t			softirq_time;
	ktime_t			offset;
};

enum  hrtimer_base_type {
	HRTIMER_BASE_MONOTONIC,
	HRTIMER_BASE_REALTIME,
	HRTIMER_BASE_BOOTTIME,
	HRTIMER_BASE_TAI,
	HRTIMER_MAX_CLOCK_BASES,
};

/*
 * struct hrtimer_cpu_base - the per cpu clock bases
 * @lock:		lock protecting the base and associated clock bases
 *			and timers
 * @cpu:		cpu number
 * @active_bases:	Bitfield to mark bases with active timers
 * @clock_was_set:	Indicates that clock was set from irq context.
 * @expires_next:	absolute time of the next event which was scheduled
 *			via clock_set_next_event()
 * @hres_active:	State of high resolution mode
 * @hang_detected:	The last hrtimer interrupt detected a hang
 * @nr_events:		Total number of hrtimer interrupt events
 * @nr_retries:		Total number of hrtimer interrupt retries
 * @nr_hangs:		Total number of hrtimer interrupt hangs
 * @max_hang_time:	Maximum time spent in hrtimer_interrupt
 * @clock_base:		array of clock bases for this cpu
 */
struct hrtimer_cpu_base {
	raw_spinlock_t			lock;
	unsigned int			cpu;
	unsigned int			active_bases;
	unsigned int			clock_was_set;
#ifdef CONFIG_HIGH_RES_TIMERS
	ktime_t				expires_next;
	int				hres_active;
	int				hang_detected;
	unsigned long			nr_events;
	unsigned long			nr_retries;
	unsigned long			nr_hangs;
	ktime_t				max_hang_time;
#endif
	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
};

static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
{
	timer->node.expires = time;
	timer->_softexpires = time;
}

static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
{
	timer->_softexpires = time;
	timer->node.expires = ktime_add_safe(time, delta);
}

static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
{
	timer->_softexpires = time;
	timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
}

static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
{
	timer->node.expires.tv64 = tv64;
	timer->_softexpires.tv64 = tv64;
}

static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
{
	timer->node.expires = ktime_add_safe(timer->node.expires, time);
	timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
}

static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
{
	timer->node.expires = ktime_add_ns(timer->node.expires, ns);
	timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
}

static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
{
	return timer->node.expires;
}

static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
{
	return timer->_softexpires;
}

static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
{
	return timer->node.expires.tv64;
}
static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
{
	return timer->_softexpires.tv64;
}

static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
{
	return ktime_to_ns(timer->node.expires);
}

static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
{
	return ktime_sub(timer->node.expires, timer->base->get_time());
}

#ifdef CONFIG_HIGH_RES_TIMERS
struct clock_event_device;

extern void hrtimer_interrupt(struct clock_event_device *dev);

/*
 * In high resolution mode the time reference must be read accurate
 */
static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
{
	return timer->base->get_time();
}

static inline int hrtimer_is_hres_active(struct hrtimer *timer)
{
	return timer->base->cpu_base->hres_active;
}

extern void hrtimer_peek_ahead_timers(void);

/*
 * The resolution of the clocks. The resolution value is returned in
 * the clock_getres() system call to give application programmers an
 * idea of the (in)accuracy of timers. Timer values are rounded up to
 * this resolution values.
 */
# define HIGH_RES_NSEC		1
# define KTIME_HIGH_RES		(ktime_t) { .tv64 = HIGH_RES_NSEC }
# define MONOTONIC_RES_NSEC	HIGH_RES_NSEC
# define KTIME_MONOTONIC_RES	KTIME_HIGH_RES

extern void clock_was_set_delayed(void);

#else

# define MONOTONIC_RES_NSEC	LOW_RES_NSEC
# define KTIME_MONOTONIC_RES	KTIME_LOW_RES

static inline void hrtimer_peek_ahead_timers(void) { }

/*
 * In non high resolution mode the time reference is taken from
 * the base softirq time variable.
 */
static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
{
	return timer->base->softirq_time;
}

static inline int hrtimer_is_hres_active(struct hrtimer *timer)
{
	return 0;
}

static inline void clock_was_set_delayed(void) { }

#endif

extern void clock_was_set(void);
#ifdef CONFIG_TIMERFD
extern void timerfd_clock_was_set(void);
#else
static inline void timerfd_clock_was_set(void) { }
#endif
extern void hrtimers_resume(void);

DECLARE_PER_CPU(struct tick_device, tick_cpu_device);


/* Exported timer functions: */

/* Initialize timers: */
extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
			 enum hrtimer_mode mode);

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
				  enum hrtimer_mode mode);

extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
#else
static inline void hrtimer_init_on_stack(struct hrtimer *timer,
					 clockid_t which_clock,
					 enum hrtimer_mode mode)
{
	hrtimer_init(timer, which_clock, mode);
}
static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
#endif

/* Basic timer operations: */
extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
			 const enum hrtimer_mode mode);
extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
			unsigned long range_ns, const enum hrtimer_mode mode);
extern int
__hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
			 unsigned long delta_ns,
			 const enum hrtimer_mode mode, int wakeup);

extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);

static inline int hrtimer_start_expires(struct hrtimer *timer,
						enum hrtimer_mode mode)
{
	unsigned long delta;
	ktime_t soft, hard;
	soft = hrtimer_get_softexpires(timer);
	hard = hrtimer_get_expires(timer);
	delta = ktime_to_ns(ktime_sub(hard, soft));
	return hrtimer_start_range_ns(timer, soft, delta, mode);
}

static inline int hrtimer_restart(struct hrtimer *timer)
{
	return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}

/* Query timers: */
extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);

extern ktime_t hrtimer_get_next_event(void);

/*
 * A timer is active, when it is enqueued into the rbtree or the
 * callback function is running or it's in the state of being migrated
 * to another cpu.
 */
static inline int hrtimer_active(const struct hrtimer *timer)
{
	return timer->state != HRTIMER_STATE_INACTIVE;
}

/*
 * Helper function to check, whether the timer is on one of the queues
 */
static inline int hrtimer_is_queued(struct hrtimer *timer)
{
	return timer->state & HRTIMER_STATE_ENQUEUED;
}

/*
 * Helper function to check, whether the timer is running the callback
 * function
 */
static inline int hrtimer_callback_running(struct hrtimer *timer)
{
	return timer->state & HRTIMER_STATE_CALLBACK;
}

/* Forward a hrtimer so it expires after now: */
extern u64
hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);

/* Forward a hrtimer so it expires after the hrtimer's current now */
static inline u64 hrtimer_forward_now(struct hrtimer *timer,
				      ktime_t interval)
{
	return hrtimer_forward(timer, timer->base->get_time(), interval);
}

/* Precise sleep: */
extern long hrtimer_nanosleep(struct timespec *rqtp,
			      struct timespec __user *rmtp,
			      const enum hrtimer_mode mode,
			      const clockid_t clockid);
extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);

extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
				 struct task_struct *tsk);

extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
						const enum hrtimer_mode mode);
extern int schedule_hrtimeout_range_clock(ktime_t *expires,
		unsigned long delta, const enum hrtimer_mode mode, int clock);
extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);

/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);
extern void hrtimer_run_pending(void);

/* Bootup initialization: */
extern void __init hrtimers_init(void);

/* Show pending timers: */
extern void sysrq_timer_list_show(void);

#endif