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 not be affected by any timer
40 * placement heuristics (like, NOHZ) and will always expire on the CPU
41 * on which the timer was enqueued.
42 *
43 * Note: Because enqueuing of timers can migrate the timer from one
44 * CPU to another, pinned timers are not guaranteed to stay on the
45 * initialy selected CPU. They move to the CPU on which the enqueue
46 * function is invoked via mod_timer() or add_timer(). If the timer
47 * should be placed on a particular CPU, then add_timer_on() has to be
48 * used.
49 */
50 #define TIMER_CPUMASK 0x0003FFFF
51 #define TIMER_MIGRATING 0x00040000
52 #define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
53 #define TIMER_DEFERRABLE 0x00080000
54 #define TIMER_PINNED 0x00100000
55 #define TIMER_IRQSAFE 0x00200000
56 #define TIMER_INIT_FLAGS (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
57 #define TIMER_ARRAYSHIFT 22
58 #define TIMER_ARRAYMASK 0xFFC00000
59
60 #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
61
62 #define __TIMER_INITIALIZER(_function, _flags) { \
63 .entry = { .next = TIMER_ENTRY_STATIC }, \
64 .function = (_function), \
65 .flags = (_flags), \
66 __TIMER_LOCKDEP_MAP_INITIALIZER(FILE_LINE) \
67 }
68
69 #define DEFINE_TIMER(_name, _function) \
70 struct timer_list _name = \
71 __TIMER_INITIALIZER(_function, 0)
72
73 /*
74 * LOCKDEP and DEBUG timer interfaces.
75 */
76 void init_timer_key(struct timer_list *timer,
77 void (*func)(struct timer_list *), unsigned int flags,
78 const char *name, struct lock_class_key *key);
79
80 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
81 extern void init_timer_on_stack_key(struct timer_list *timer,
82 void (*func)(struct timer_list *),
83 unsigned int flags, const char *name,
84 struct lock_class_key *key);
85 #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)86 static inline void init_timer_on_stack_key(struct timer_list *timer,
87 void (*func)(struct timer_list *),
88 unsigned int flags,
89 const char *name,
90 struct lock_class_key *key)
91 {
92 init_timer_key(timer, func, flags, name, key);
93 }
94 #endif
95
96 #ifdef CONFIG_LOCKDEP
97 #define __init_timer(_timer, _fn, _flags) \
98 do { \
99 static struct lock_class_key __key; \
100 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
101 } while (0)
102
103 #define __init_timer_on_stack(_timer, _fn, _flags) \
104 do { \
105 static struct lock_class_key __key; \
106 init_timer_on_stack_key((_timer), (_fn), (_flags), \
107 #_timer, &__key); \
108 } while (0)
109 #else
110 #define __init_timer(_timer, _fn, _flags) \
111 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
112 #define __init_timer_on_stack(_timer, _fn, _flags) \
113 init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
114 #endif
115
116 /**
117 * timer_setup - prepare a timer for first use
118 * @timer: the timer in question
119 * @callback: the function to call when timer expires
120 * @flags: any TIMER_* flags
121 *
122 * Regular timer initialization should use either DEFINE_TIMER() above,
123 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
124 * be used and must be balanced with a call to destroy_timer_on_stack().
125 */
126 #define timer_setup(timer, callback, flags) \
127 __init_timer((timer), (callback), (flags))
128
129 #define timer_setup_on_stack(timer, callback, flags) \
130 __init_timer_on_stack((timer), (callback), (flags))
131
132 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
133 extern void destroy_timer_on_stack(struct timer_list *timer);
134 #else
destroy_timer_on_stack(struct timer_list * timer)135 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
136 #endif
137
138 #define from_timer(var, callback_timer, timer_fieldname) \
139 container_of(callback_timer, typeof(*var), timer_fieldname)
140
141 /**
142 * timer_pending - is a timer pending?
143 * @timer: the timer in question
144 *
145 * timer_pending will tell whether a given timer is currently pending,
146 * or not. Callers must ensure serialization wrt. other operations done
147 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
148 *
149 * return value: 1 if the timer is pending, 0 if not.
150 */
timer_pending(const struct timer_list * timer)151 static inline int timer_pending(const struct timer_list * timer)
152 {
153 return !hlist_unhashed_lockless(&timer->entry);
154 }
155
156 extern void add_timer_on(struct timer_list *timer, int cpu);
157 extern int mod_timer(struct timer_list *timer, unsigned long expires);
158 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
159 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
160
161 /*
162 * The jiffies value which is added to now, when there is no timer
163 * in the timer wheel:
164 */
165 #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
166
167 extern void add_timer(struct timer_list *timer);
168
169 extern int try_to_del_timer_sync(struct timer_list *timer);
170 extern int timer_delete_sync(struct timer_list *timer);
171 extern int timer_delete(struct timer_list *timer);
172 extern int timer_shutdown_sync(struct timer_list *timer);
173 extern int timer_shutdown(struct timer_list *timer);
174
175 /**
176 * del_timer_sync - Delete a pending timer and wait for a running callback
177 * @timer: The timer to be deleted
178 *
179 * See timer_delete_sync() for detailed explanation.
180 *
181 * Do not use in new code. Use timer_delete_sync() instead.
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 */
del_timer(struct timer_list * timer)196 static inline int del_timer(struct timer_list *timer)
197 {
198 return timer_delete(timer);
199 }
200
201 extern void init_timers(void);
202 struct hrtimer;
203 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
204
205 unsigned long __round_jiffies(unsigned long j, int cpu);
206 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
207 unsigned long round_jiffies(unsigned long j);
208 unsigned long round_jiffies_relative(unsigned long j);
209
210 unsigned long __round_jiffies_up(unsigned long j, int cpu);
211 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
212 unsigned long round_jiffies_up(unsigned long j);
213 unsigned long round_jiffies_up_relative(unsigned long j);
214
215 #ifdef CONFIG_HOTPLUG_CPU
216 int timers_prepare_cpu(unsigned int cpu);
217 int timers_dead_cpu(unsigned int cpu);
218 #else
219 #define timers_prepare_cpu NULL
220 #define timers_dead_cpu NULL
221 #endif
222
223 #endif
224