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(FILE_LINE) \ |
81 | } |
82 | |
83 | #define DEFINE_TIMER(_name, _function) \ |
84 | struct timer_list _name = \ |
85 | __TIMER_INITIALIZER(_function, 0) |
86 | |
87 | /* |
88 | * LOCKDEP and DEBUG timer interfaces. |
89 | */ |
90 | void init_timer_key(struct timer_list *timer, |
91 | void (*func)(struct timer_list *), unsigned int flags, |
92 | const char *name, struct lock_class_key *key); |
93 | |
94 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
95 | extern void init_timer_on_stack_key(struct timer_list *timer, |
96 | void (*func)(struct timer_list *), |
97 | unsigned int flags, const char *name, |
98 | struct lock_class_key *key); |
99 | #else |
100 | static inline void init_timer_on_stack_key(struct timer_list *timer, |
101 | void (*func)(struct timer_list *), |
102 | unsigned int flags, |
103 | const char *name, |
104 | struct lock_class_key *key) |
105 | { |
106 | init_timer_key(timer, func, flags, name, key); |
107 | } |
108 | #endif |
109 | |
110 | #ifdef CONFIG_LOCKDEP |
111 | #define __init_timer(_timer, _fn, _flags) \ |
112 | do { \ |
113 | static struct lock_class_key __key; \ |
114 | init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\ |
115 | } while (0) |
116 | |
117 | #define __init_timer_on_stack(_timer, _fn, _flags) \ |
118 | do { \ |
119 | static struct lock_class_key __key; \ |
120 | init_timer_on_stack_key((_timer), (_fn), (_flags), \ |
121 | #_timer, &__key); \ |
122 | } while (0) |
123 | #else |
124 | #define __init_timer(_timer, _fn, _flags) \ |
125 | init_timer_key((_timer), (_fn), (_flags), NULL, NULL) |
126 | #define __init_timer_on_stack(_timer, _fn, _flags) \ |
127 | init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL) |
128 | #endif |
129 | |
130 | /** |
131 | * timer_setup - prepare a timer for first use |
132 | * @timer: the timer in question |
133 | * @callback: the function to call when timer expires |
134 | * @flags: any TIMER_* flags |
135 | * |
136 | * Regular timer initialization should use either DEFINE_TIMER() above, |
137 | * or timer_setup(). For timers on the stack, timer_setup_on_stack() must |
138 | * be used and must be balanced with a call to destroy_timer_on_stack(). |
139 | */ |
140 | #define timer_setup(timer, callback, flags) \ |
141 | __init_timer((timer), (callback), (flags)) |
142 | |
143 | #define timer_setup_on_stack(timer, callback, flags) \ |
144 | __init_timer_on_stack((timer), (callback), (flags)) |
145 | |
146 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
147 | extern void destroy_timer_on_stack(struct timer_list *timer); |
148 | #else |
149 | static inline void destroy_timer_on_stack(struct timer_list *timer) { } |
150 | #endif |
151 | |
152 | #define from_timer(var, callback_timer, timer_fieldname) \ |
153 | container_of(callback_timer, typeof(*var), timer_fieldname) |
154 | |
155 | /** |
156 | * timer_pending - is a timer pending? |
157 | * @timer: the timer in question |
158 | * |
159 | * timer_pending will tell whether a given timer is currently pending, |
160 | * or not. Callers must ensure serialization wrt. other operations done |
161 | * to this timer, eg. interrupt contexts, or other CPUs on SMP. |
162 | * |
163 | * return value: 1 if the timer is pending, 0 if not. |
164 | */ |
165 | static inline int timer_pending(const struct timer_list * timer) |
166 | { |
167 | return !hlist_unhashed_lockless(h: &timer->entry); |
168 | } |
169 | |
170 | extern void add_timer_on(struct timer_list *timer, int cpu); |
171 | extern int mod_timer(struct timer_list *timer, unsigned long expires); |
172 | extern int mod_timer_pending(struct timer_list *timer, unsigned long expires); |
173 | extern int timer_reduce(struct timer_list *timer, unsigned long expires); |
174 | |
175 | /* |
176 | * The jiffies value which is added to now, when there is no timer |
177 | * in the timer wheel: |
178 | */ |
179 | #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1) |
180 | |
181 | extern void add_timer(struct timer_list *timer); |
182 | |
183 | extern int try_to_del_timer_sync(struct timer_list *timer); |
184 | extern int timer_delete_sync(struct timer_list *timer); |
185 | extern int timer_delete(struct timer_list *timer); |
186 | extern int timer_shutdown_sync(struct timer_list *timer); |
187 | extern int timer_shutdown(struct timer_list *timer); |
188 | |
189 | /** |
190 | * del_timer_sync - Delete a pending timer and wait for a running callback |
191 | * @timer: The timer to be deleted |
192 | * |
193 | * See timer_delete_sync() for detailed explanation. |
194 | * |
195 | * Do not use in new code. Use timer_delete_sync() instead. |
196 | */ |
197 | static inline int del_timer_sync(struct timer_list *timer) |
198 | { |
199 | return timer_delete_sync(timer); |
200 | } |
201 | |
202 | /** |
203 | * del_timer - Delete a pending timer |
204 | * @timer: The timer to be deleted |
205 | * |
206 | * See timer_delete() for detailed explanation. |
207 | * |
208 | * Do not use in new code. Use timer_delete() instead. |
209 | */ |
210 | static inline int del_timer(struct timer_list *timer) |
211 | { |
212 | return timer_delete(timer); |
213 | } |
214 | |
215 | extern void init_timers(void); |
216 | struct hrtimer; |
217 | extern enum hrtimer_restart it_real_fn(struct hrtimer *); |
218 | |
219 | unsigned long __round_jiffies(unsigned long j, int cpu); |
220 | unsigned long __round_jiffies_relative(unsigned long j, int cpu); |
221 | unsigned long round_jiffies(unsigned long j); |
222 | unsigned long round_jiffies_relative(unsigned long j); |
223 | |
224 | unsigned long __round_jiffies_up(unsigned long j, int cpu); |
225 | unsigned long __round_jiffies_up_relative(unsigned long j, int cpu); |
226 | unsigned long round_jiffies_up(unsigned long j); |
227 | unsigned long round_jiffies_up_relative(unsigned long j); |
228 | |
229 | #ifdef CONFIG_HOTPLUG_CPU |
230 | int timers_prepare_cpu(unsigned int cpu); |
231 | int timers_dead_cpu(unsigned int cpu); |
232 | #else |
233 | #define timers_prepare_cpu NULL |
234 | #define timers_dead_cpu NULL |
235 | #endif |
236 | |
237 | #endif |
238 | |