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 * A deferrable timer will work normally when the system is busy, but
41 * will not cause a CPU to come out of idle just to service it; instead,
42 * the timer will be serviced when the CPU eventually wakes up with a
43 * subsequent non-deferrable timer.
44 *
45 * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
46 * the completion of the running instance from IRQ handlers, for example,
47 * 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 #define TIMER_CPUMASK 0x0003FFFF
54 #define TIMER_MIGRATING 0x00040000
55 #define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
56 #define TIMER_DEFERRABLE 0x00080000
57 #define TIMER_PINNED 0x00100000
58 #define TIMER_IRQSAFE 0x00200000
59 #define TIMER_ARRAYSHIFT 22
60 #define TIMER_ARRAYMASK 0xFFC00000
61
62 #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
63
64 #define __TIMER_INITIALIZER(_function, _flags) { \
65 .entry = { .next = TIMER_ENTRY_STATIC }, \
66 .function = (_function), \
67 .flags = (_flags), \
68 __TIMER_LOCKDEP_MAP_INITIALIZER( \
69 __FILE__ ":" __stringify(__LINE__)) \
70 }
71
72 #define DEFINE_TIMER(_name, _function) \
73 struct timer_list _name = \
74 __TIMER_INITIALIZER(_function, 0)
75
76 /*
77 * LOCKDEP and DEBUG timer interfaces.
78 */
79 void init_timer_key(struct timer_list *timer,
80 void (*func)(struct timer_list *), unsigned int flags,
81 const char *name, struct lock_class_key *key);
82
83 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
84 extern void init_timer_on_stack_key(struct timer_list *timer,
85 void (*func)(struct timer_list *),
86 unsigned int flags, const char *name,
87 struct lock_class_key *key);
88 #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)89 static inline void init_timer_on_stack_key(struct timer_list *timer,
90 void (*func)(struct timer_list *),
91 unsigned int flags,
92 const char *name,
93 struct lock_class_key *key)
94 {
95 init_timer_key(timer, func, flags, name, key);
96 }
97 #endif
98
99 #ifdef CONFIG_LOCKDEP
100 #define __init_timer(_timer, _fn, _flags) \
101 do { \
102 static struct lock_class_key __key; \
103 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
104 } while (0)
105
106 #define __init_timer_on_stack(_timer, _fn, _flags) \
107 do { \
108 static struct lock_class_key __key; \
109 init_timer_on_stack_key((_timer), (_fn), (_flags), \
110 #_timer, &__key); \
111 } while (0)
112 #else
113 #define __init_timer(_timer, _fn, _flags) \
114 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
115 #define __init_timer_on_stack(_timer, _fn, _flags) \
116 init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
117 #endif
118
119 /**
120 * timer_setup - prepare a timer for first use
121 * @timer: the timer in question
122 * @callback: the function to call when timer expires
123 * @flags: any TIMER_* flags
124 *
125 * Regular timer initialization should use either DEFINE_TIMER() above,
126 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
127 * be used and must be balanced with a call to destroy_timer_on_stack().
128 */
129 #define timer_setup(timer, callback, flags) \
130 __init_timer((timer), (callback), (flags))
131
132 #define timer_setup_on_stack(timer, callback, flags) \
133 __init_timer_on_stack((timer), (callback), (flags))
134
135 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
136 extern void destroy_timer_on_stack(struct timer_list *timer);
137 #else
destroy_timer_on_stack(struct timer_list * timer)138 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
139 #endif
140
141 #define from_timer(var, callback_timer, timer_fieldname) \
142 container_of(callback_timer, typeof(*var), timer_fieldname)
143
144 /**
145 * timer_pending - is a timer pending?
146 * @timer: the timer in question
147 *
148 * timer_pending will tell whether a given timer is currently pending,
149 * or not. Callers must ensure serialization wrt. other operations done
150 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
151 *
152 * return value: 1 if the timer is pending, 0 if not.
153 */
timer_pending(const struct timer_list * timer)154 static inline int timer_pending(const struct timer_list * timer)
155 {
156 return timer->entry.pprev != NULL;
157 }
158
159 extern void add_timer_on(struct timer_list *timer, int cpu);
160 extern int del_timer(struct timer_list * timer);
161 extern int mod_timer(struct timer_list *timer, unsigned long expires);
162 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
163 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
164
165 /*
166 * The jiffies value which is added to now, when there is no timer
167 * in the timer wheel:
168 */
169 #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
170
171 extern void add_timer(struct timer_list *timer);
172
173 extern int try_to_del_timer_sync(struct timer_list *timer);
174
175 #ifdef CONFIG_SMP
176 extern int del_timer_sync(struct timer_list *timer);
177 #else
178 # define del_timer_sync(t) del_timer(t)
179 #endif
180
181 #define del_singleshot_timer_sync(t) del_timer_sync(t)
182
183 extern void init_timers(void);
184 extern void run_local_timers(void);
185 struct hrtimer;
186 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
187
188 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
189 struct ctl_table;
190
191 extern unsigned int sysctl_timer_migration;
192 int timer_migration_handler(struct ctl_table *table, int write,
193 void __user *buffer, size_t *lenp,
194 loff_t *ppos);
195 #endif
196
197 unsigned long __round_jiffies(unsigned long j, int cpu);
198 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
199 unsigned long round_jiffies(unsigned long j);
200 unsigned long round_jiffies_relative(unsigned long j);
201
202 unsigned long __round_jiffies_up(unsigned long j, int cpu);
203 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
204 unsigned long round_jiffies_up(unsigned long j);
205 unsigned long round_jiffies_up_relative(unsigned long j);
206
207 #ifdef CONFIG_HOTPLUG_CPU
208 int timers_prepare_cpu(unsigned int cpu);
209 int timers_dead_cpu(unsigned int cpu);
210 #else
211 #define timers_prepare_cpu NULL
212 #define timers_dead_cpu NULL
213 #endif
214
215 #endif
216