1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_TIMER_H
3#define _LINUX_TIMER_H
4
5#include <linux/list.h>
6#include <linux/ktime.h>
7#include <linux/stddef.h>
8#include <linux/debugobjects.h>
9#include <linux/stringify.h>
10#include <linux/timer_types.h>
11
12#ifdef CONFIG_LOCKDEP
13/*
14 * NB: because we have to copy the lockdep_map, setting the lockdep_map key
15 * (second argument) here is required, otherwise it could be initialised to
16 * the copy of the lockdep_map later! We use the pointer to and the string
17 * "<file>:<line>" as the key resp. the name of the lockdep_map.
18 */
19#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
20 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
21#else
22#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
23#endif
24
25/*
26 * @TIMER_DEFERRABLE: A deferrable timer will work normally when the
27 * system is busy, but will not cause a CPU to come out of idle just
28 * to service it; instead, the timer will be serviced when the CPU
29 * eventually wakes up with a subsequent non-deferrable timer.
30 *
31 * @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
32 * it's safe to wait for the completion of the running instance from
33 * IRQ handlers, for example, by calling timer_delete_sync().
34 *
35 * Note: The irq disabled callback execution is a special case for
36 * workqueue locking issues. It's not meant for executing random crap
37 * with interrupts disabled. Abuse is monitored!
38 *
39 * @TIMER_PINNED: A pinned timer will always expire on the CPU on which the
40 * timer was enqueued. When a particular CPU is required, add_timer_on()
41 * has to be used. Enqueue via mod_timer() and add_timer() is always done
42 * on the local CPU.
43 */
44#define TIMER_CPUMASK 0x0003FFFF
45#define TIMER_MIGRATING 0x00040000
46#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
47#define TIMER_DEFERRABLE 0x00080000
48#define TIMER_PINNED 0x00100000
49#define TIMER_IRQSAFE 0x00200000
50#define TIMER_INIT_FLAGS (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
51#define TIMER_ARRAYSHIFT 22
52#define TIMER_ARRAYMASK 0xFFC00000
53
54#define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
55
56#define __TIMER_INITIALIZER(_function, _flags) { \
57 .entry = { .next = TIMER_ENTRY_STATIC }, \
58 .function = (_function), \
59 .flags = (_flags), \
60 __TIMER_LOCKDEP_MAP_INITIALIZER(FILE_LINE) \
61 }
62
63#define DEFINE_TIMER(_name, _function) \
64 struct timer_list _name = \
65 __TIMER_INITIALIZER(_function, 0)
66
67/*
68 * LOCKDEP and DEBUG timer interfaces.
69 */
70void timer_init_key(struct timer_list *timer,
71 void (*func)(struct timer_list *), unsigned int flags,
72 const char *name, struct lock_class_key *key);
73
74#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
75extern void timer_init_key_on_stack(struct timer_list *timer,
76 void (*func)(struct timer_list *),
77 unsigned int flags, const char *name,
78 struct lock_class_key *key);
79#else
80static inline void timer_init_key_on_stack(struct timer_list *timer,
81 void (*func)(struct timer_list *),
82 unsigned int flags,
83 const char *name,
84 struct lock_class_key *key)
85{
86 timer_init_key(timer, func, flags, name, key);
87}
88#endif
89
90#ifdef CONFIG_LOCKDEP
91#define __timer_init(_timer, _fn, _flags) \
92 do { \
93 static struct lock_class_key __key; \
94 timer_init_key((_timer), (_fn), (_flags), #_timer, &__key);\
95 } while (0)
96
97#define __timer_init_on_stack(_timer, _fn, _flags) \
98 do { \
99 static struct lock_class_key __key; \
100 timer_init_key_on_stack((_timer), (_fn), (_flags), \
101 #_timer, &__key); \
102 } while (0)
103#else
104#define __timer_init(_timer, _fn, _flags) \
105 timer_init_key((_timer), (_fn), (_flags), NULL, NULL)
106#define __timer_init_on_stack(_timer, _fn, _flags) \
107 timer_init_key_on_stack((_timer), (_fn), (_flags), NULL, NULL)
108#endif
109
110/**
111 * timer_setup - prepare a timer for first use
112 * @timer: the timer in question
113 * @callback: the function to call when timer expires
114 * @flags: any TIMER_* flags
115 *
116 * Regular timer initialization should use either DEFINE_TIMER() above,
117 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
118 * be used and must be balanced with a call to timer_destroy_on_stack().
119 */
120#define timer_setup(timer, callback, flags) \
121 __timer_init((timer), (callback), (flags))
122
123#define timer_setup_on_stack(timer, callback, flags) \
124 __timer_init_on_stack((timer), (callback), (flags))
125
126#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
127extern void timer_destroy_on_stack(struct timer_list *timer);
128#else
129static inline void timer_destroy_on_stack(struct timer_list *timer) { }
130#endif
131
132#define timer_container_of(var, callback_timer, timer_fieldname) \
133 container_of(callback_timer, typeof(*var), timer_fieldname)
134
135/**
136 * timer_pending - is a timer pending?
137 * @timer: the timer in question
138 *
139 * timer_pending will tell whether a given timer is currently pending,
140 * or not. Callers must ensure serialization wrt. other operations done
141 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
142 *
143 * Returns: 1 if the timer is pending, 0 if not.
144 */
145static inline int timer_pending(const struct timer_list * timer)
146{
147 return !hlist_unhashed_lockless(h: &timer->entry);
148}
149
150extern void add_timer_on(struct timer_list *timer, int cpu);
151extern int mod_timer(struct timer_list *timer, unsigned long expires);
152extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
153extern int timer_reduce(struct timer_list *timer, unsigned long expires);
154
155/*
156 * The jiffies value which is added to now, when there is no timer
157 * in the timer wheel:
158 */
159#define TIMER_NEXT_MAX_DELTA ((1UL << 30) - 1)
160
161extern void add_timer(struct timer_list *timer);
162extern void add_timer_local(struct timer_list *timer);
163extern void add_timer_global(struct timer_list *timer);
164
165extern int timer_delete_sync_try(struct timer_list *timer);
166extern int timer_delete_sync(struct timer_list *timer);
167extern int timer_delete(struct timer_list *timer);
168extern int timer_shutdown_sync(struct timer_list *timer);
169extern int timer_shutdown(struct timer_list *timer);
170
171extern void timers_init(void);
172struct hrtimer;
173extern enum hrtimer_restart it_real_fn(struct hrtimer *);
174
175unsigned long __round_jiffies_relative(unsigned long j, int cpu);
176unsigned long round_jiffies(unsigned long j);
177unsigned long round_jiffies_relative(unsigned long j);
178
179unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
180unsigned long round_jiffies_up(unsigned long j);
181unsigned long round_jiffies_up_relative(unsigned long j);
182
183#ifdef CONFIG_HOTPLUG_CPU
184int timers_prepare_cpu(unsigned int cpu);
185int timers_dead_cpu(unsigned int cpu);
186#else
187#define timers_prepare_cpu NULL
188#define timers_dead_cpu NULL
189#endif
190
191#endif
192

source code of linux/include/linux/timer.h

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