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 del_timer_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 */
70 void init_timer_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
75 extern void init_timer_on_stack_key(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
init_timer_on_stack_key(struct timer_list * timer,void (* func)(struct timer_list *),unsigned int flags,const char * name,struct lock_class_key * key)80 static inline void init_timer_on_stack_key(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 init_timer_key(timer, func, flags, name, key);
87 }
88 #endif
89
90 #ifdef CONFIG_LOCKDEP
91 #define __init_timer(_timer, _fn, _flags) \
92 do { \
93 static struct lock_class_key __key; \
94 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
95 } while (0)
96
97 #define __init_timer_on_stack(_timer, _fn, _flags) \
98 do { \
99 static struct lock_class_key __key; \
100 init_timer_on_stack_key((_timer), (_fn), (_flags), \
101 #_timer, &__key); \
102 } while (0)
103 #else
104 #define __init_timer(_timer, _fn, _flags) \
105 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
106 #define __init_timer_on_stack(_timer, _fn, _flags) \
107 init_timer_on_stack_key((_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 destroy_timer_on_stack().
119 */
120 #define timer_setup(timer, callback, flags) \
121 __init_timer((timer), (callback), (flags))
122
123 #define timer_setup_on_stack(timer, callback, flags) \
124 __init_timer_on_stack((timer), (callback), (flags))
125
126 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
127 extern void destroy_timer_on_stack(struct timer_list *timer);
128 #else
destroy_timer_on_stack(struct timer_list * timer)129 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
130 #endif
131
132 #define from_timer(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 */
timer_pending(const struct timer_list * timer)145 static inline int timer_pending(const struct timer_list * timer)
146 {
147 return !hlist_unhashed_lockless(&timer->entry);
148 }
149
150 extern void add_timer_on(struct timer_list *timer, int cpu);
151 extern int mod_timer(struct timer_list *timer, unsigned long expires);
152 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
153 extern 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 NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
160
161 extern void add_timer(struct timer_list *timer);
162 extern void add_timer_local(struct timer_list *timer);
163 extern void add_timer_global(struct timer_list *timer);
164
165 extern int try_to_del_timer_sync(struct timer_list *timer);
166 extern int timer_delete_sync(struct timer_list *timer);
167 extern int timer_delete(struct timer_list *timer);
168 extern int timer_shutdown_sync(struct timer_list *timer);
169 extern int timer_shutdown(struct timer_list *timer);
170
171 /**
172 * del_timer_sync - Delete a pending timer and wait for a running callback
173 * @timer: The timer to be deleted
174 *
175 * See timer_delete_sync() for detailed explanation.
176 *
177 * Do not use in new code. Use timer_delete_sync() instead.
178 *
179 * Returns:
180 * * %0 - The timer was not pending
181 * * %1 - The timer was pending and deactivated
182 */
del_timer_sync(struct timer_list * timer)183 static inline int del_timer_sync(struct timer_list *timer)
184 {
185 return timer_delete_sync(timer);
186 }
187
188 /**
189 * del_timer - Delete a pending timer
190 * @timer: The timer to be deleted
191 *
192 * See timer_delete() for detailed explanation.
193 *
194 * Do not use in new code. Use timer_delete() instead.
195 *
196 * Returns:
197 * * %0 - The timer was not pending
198 * * %1 - The timer was pending and deactivated
199 */
del_timer(struct timer_list * timer)200 static inline int del_timer(struct timer_list *timer)
201 {
202 return timer_delete(timer);
203 }
204
205 extern void init_timers(void);
206 struct hrtimer;
207 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
208
209 unsigned long __round_jiffies(unsigned long j, int cpu);
210 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
211 unsigned long round_jiffies(unsigned long j);
212 unsigned long round_jiffies_relative(unsigned long j);
213
214 unsigned long __round_jiffies_up(unsigned long j, int cpu);
215 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
216 unsigned long round_jiffies_up(unsigned long j);
217 unsigned long round_jiffies_up_relative(unsigned long j);
218
219 #ifdef CONFIG_HOTPLUG_CPU
220 int timers_prepare_cpu(unsigned int cpu);
221 int timers_dead_cpu(unsigned int cpu);
222 #else
223 #define timers_prepare_cpu NULL
224 #define timers_dead_cpu NULL
225 #endif
226
227 #endif
228