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
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)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 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
destroy_timer_on_stack(struct timer_list * timer)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 */
timer_pending(const struct timer_list * timer)166 static inline int timer_pending(const struct timer_list * timer)
167 {
168 return !hlist_unhashed_lockless(&timer->entry);
169 }
170
171 extern void add_timer_on(struct timer_list *timer, int cpu);
172 extern int del_timer(struct timer_list * timer);
173 extern int mod_timer(struct timer_list *timer, unsigned long expires);
174 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
175 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
176
177 /*
178 * The jiffies value which is added to now, when there is no timer
179 * in the timer wheel:
180 */
181 #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
182
183 extern void add_timer(struct timer_list *timer);
184
185 extern int try_to_del_timer_sync(struct timer_list *timer);
186
187 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
188 extern int del_timer_sync(struct timer_list *timer);
189 #else
190 # define del_timer_sync(t) del_timer(t)
191 #endif
192
193 #define del_singleshot_timer_sync(t) del_timer_sync(t)
194
195 extern void init_timers(void);
196 extern void run_local_timers(void);
197 struct hrtimer;
198 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
199
200 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
201 struct ctl_table;
202
203 extern unsigned int sysctl_timer_migration;
204 int timer_migration_handler(struct ctl_table *table, int write,
205 void *buffer, size_t *lenp, loff_t *ppos);
206 #endif
207
208 unsigned long __round_jiffies(unsigned long j, int cpu);
209 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
210 unsigned long round_jiffies(unsigned long j);
211 unsigned long round_jiffies_relative(unsigned long j);
212
213 unsigned long __round_jiffies_up(unsigned long j, int cpu);
214 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
215 unsigned long round_jiffies_up(unsigned long j);
216 unsigned long round_jiffies_up_relative(unsigned long j);
217
218 #ifdef CONFIG_HOTPLUG_CPU
219 int timers_prepare_cpu(unsigned int cpu);
220 int timers_dead_cpu(unsigned int cpu);
221 #else
222 #define timers_prepare_cpu NULL
223 #define timers_dead_cpu NULL
224 #endif
225
226 #endif
227
