Line data Source code
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 :
11 : struct timer_list {
12 : /*
13 : * All fields that change during normal runtime grouped to the
14 : * same cacheline
15 : */
16 : struct hlist_node entry;
17 : unsigned long expires;
18 : void (*function)(struct timer_list *);
19 : u32 flags;
20 :
21 : #ifdef CONFIG_LOCKDEP
22 : struct lockdep_map lockdep_map;
23 : #endif
24 : };
25 :
26 : #ifdef CONFIG_LOCKDEP
27 : /*
28 : * NB: because we have to copy the lockdep_map, setting the lockdep_map key
29 : * (second argument) here is required, otherwise it could be initialised to
30 : * the copy of the lockdep_map later! We use the pointer to and the string
31 : * "<file>:<line>" as the key resp. the name of the lockdep_map.
32 : */
33 : #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
34 : .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
35 : #else
36 : #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
37 : #endif
38 :
39 : /**
40 : * @TIMER_DEFERRABLE: A deferrable timer will work normally when the
41 : * system is busy, but will not cause a CPU to come out of idle just
42 : * to service it; instead, the timer will be serviced when the CPU
43 : * eventually wakes up with a subsequent non-deferrable timer.
44 : *
45 : * @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
46 : * it's safe to wait for the completion of the running instance from
47 : * IRQ handlers, for example, by calling del_timer_sync().
48 : *
49 : * Note: The irq disabled callback execution is a special case for
50 : * workqueue locking issues. It's not meant for executing random crap
51 : * with interrupts disabled. Abuse is monitored!
52 : *
53 : * @TIMER_PINNED: A pinned timer will not be affected by any timer
54 : * placement heuristics (like, NOHZ) and will always expire on the CPU
55 : * on which the timer was enqueued.
56 : *
57 : * Note: Because enqueuing of timers can migrate the timer from one
58 : * CPU to another, pinned timers are not guaranteed to stay on the
59 : * initialy selected CPU. They move to the CPU on which the enqueue
60 : * function is invoked via mod_timer() or add_timer(). If the timer
61 : * should be placed on a particular CPU, then add_timer_on() has to be
62 : * used.
63 : */
64 : #define TIMER_CPUMASK 0x0003FFFF
65 : #define TIMER_MIGRATING 0x00040000
66 : #define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
67 : #define TIMER_DEFERRABLE 0x00080000
68 : #define TIMER_PINNED 0x00100000
69 : #define TIMER_IRQSAFE 0x00200000
70 : #define TIMER_INIT_FLAGS (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
71 : #define TIMER_ARRAYSHIFT 22
72 : #define TIMER_ARRAYMASK 0xFFC00000
73 :
74 : #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
75 :
76 : #define __TIMER_INITIALIZER(_function, _flags) { \
77 : .entry = { .next = TIMER_ENTRY_STATIC }, \
78 : .function = (_function), \
79 : .flags = (_flags), \
80 : __TIMER_LOCKDEP_MAP_INITIALIZER( \
81 : __FILE__ ":" __stringify(__LINE__)) \
82 : }
83 :
84 : #define DEFINE_TIMER(_name, _function) \
85 : struct timer_list _name = \
86 : __TIMER_INITIALIZER(_function, 0)
87 :
88 : /*
89 : * LOCKDEP and DEBUG timer interfaces.
90 : */
91 : void init_timer_key(struct timer_list *timer,
92 : void (*func)(struct timer_list *), unsigned int flags,
93 : const char *name, struct lock_class_key *key);
94 :
95 : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
96 : extern void init_timer_on_stack_key(struct timer_list *timer,
97 : void (*func)(struct timer_list *),
98 : unsigned int flags, const char *name,
99 : struct lock_class_key *key);
100 : #else
101 : static inline void init_timer_on_stack_key(struct timer_list *timer,
102 : void (*func)(struct timer_list *),
103 : unsigned int flags,
104 : const char *name,
105 : struct lock_class_key *key)
106 : {
107 162 : init_timer_key(timer, func, flags, name, key);
108 : }
109 : #endif
110 :
111 : #ifdef CONFIG_LOCKDEP
112 : #define __init_timer(_timer, _fn, _flags) \
113 : do { \
114 : static struct lock_class_key __key; \
115 : init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
116 : } while (0)
117 :
118 : #define __init_timer_on_stack(_timer, _fn, _flags) \
119 : do { \
120 : static struct lock_class_key __key; \
121 : init_timer_on_stack_key((_timer), (_fn), (_flags), \
122 : #_timer, &__key); \
123 : } while (0)
124 : #else
125 : #define __init_timer(_timer, _fn, _flags) \
126 : init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
127 : #define __init_timer_on_stack(_timer, _fn, _flags) \
128 : init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
129 : #endif
130 :
131 : /**
132 : * timer_setup - prepare a timer for first use
133 : * @timer: the timer in question
134 : * @callback: the function to call when timer expires
135 : * @flags: any TIMER_* flags
136 : *
137 : * Regular timer initialization should use either DEFINE_TIMER() above,
138 : * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
139 : * be used and must be balanced with a call to destroy_timer_on_stack().
140 : */
141 : #define timer_setup(timer, callback, flags) \
142 : __init_timer((timer), (callback), (flags))
143 :
144 : #define timer_setup_on_stack(timer, callback, flags) \
145 : __init_timer_on_stack((timer), (callback), (flags))
146 :
147 : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
148 : extern void destroy_timer_on_stack(struct timer_list *timer);
149 : #else
150 : static inline void destroy_timer_on_stack(struct timer_list *timer) { }
151 : #endif
152 :
153 : #define from_timer(var, callback_timer, timer_fieldname) \
154 : container_of(callback_timer, typeof(*var), timer_fieldname)
155 :
156 : /**
157 : * timer_pending - is a timer pending?
158 : * @timer: the timer in question
159 : *
160 : * timer_pending will tell whether a given timer is currently pending,
161 : * or not. Callers must ensure serialization wrt. other operations done
162 : * to this timer, eg. interrupt contexts, or other CPUs on SMP.
163 : *
164 : * return value: 1 if the timer is pending, 0 if not.
165 : */
166 : static inline int timer_pending(const struct timer_list * timer)
167 : {
168 714 : return !hlist_unhashed_lockless(&timer->entry);
169 : }
170 :
171 : extern void add_timer_on(struct timer_list *timer, int cpu);
172 : extern int mod_timer(struct timer_list *timer, unsigned long expires);
173 : extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
174 : extern int timer_reduce(struct timer_list *timer, unsigned long expires);
175 :
176 : /*
177 : * The jiffies value which is added to now, when there is no timer
178 : * in the timer wheel:
179 : */
180 : #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
181 :
182 : extern void add_timer(struct timer_list *timer);
183 :
184 : extern int try_to_del_timer_sync(struct timer_list *timer);
185 : extern int timer_delete_sync(struct timer_list *timer);
186 : extern int timer_delete(struct timer_list *timer);
187 : extern int timer_shutdown_sync(struct timer_list *timer);
188 : extern int timer_shutdown(struct timer_list *timer);
189 :
190 : /**
191 : * del_timer_sync - Delete a pending timer and wait for a running callback
192 : * @timer: The timer to be deleted
193 : *
194 : * See timer_delete_sync() for detailed explanation.
195 : *
196 : * Do not use in new code. Use timer_delete_sync() instead.
197 : */
198 : static inline int del_timer_sync(struct timer_list *timer)
199 : {
200 162 : return timer_delete_sync(timer);
201 : }
202 :
203 : /**
204 : * del_timer - Delete a pending timer
205 : * @timer: The timer to be deleted
206 : *
207 : * See timer_delete() for detailed explanation.
208 : *
209 : * Do not use in new code. Use timer_delete() instead.
210 : */
211 : static inline int del_timer(struct timer_list *timer)
212 : {
213 21 : return timer_delete(timer);
214 : }
215 :
216 : extern void init_timers(void);
217 : struct hrtimer;
218 : extern enum hrtimer_restart it_real_fn(struct hrtimer *);
219 :
220 : unsigned long __round_jiffies(unsigned long j, int cpu);
221 : unsigned long __round_jiffies_relative(unsigned long j, int cpu);
222 : unsigned long round_jiffies(unsigned long j);
223 : unsigned long round_jiffies_relative(unsigned long j);
224 :
225 : unsigned long __round_jiffies_up(unsigned long j, int cpu);
226 : unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
227 : unsigned long round_jiffies_up(unsigned long j);
228 : unsigned long round_jiffies_up_relative(unsigned long j);
229 :
230 : #ifdef CONFIG_HOTPLUG_CPU
231 : int timers_prepare_cpu(unsigned int cpu);
232 : int timers_dead_cpu(unsigned int cpu);
233 : #else
234 : #define timers_prepare_cpu NULL
235 : #define timers_dead_cpu NULL
236 : #endif
237 :
238 : #endif
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