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_ARRAYSHIFT 22
71 #define TIMER_ARRAYMASK 0xFFC00000
72
73 #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
74
75 #define __TIMER_INITIALIZER(_function, _flags) { \
76 .entry = { .next = TIMER_ENTRY_STATIC }, \
77 .function = (_function), \
78 .flags = (_flags), \
79 __TIMER_LOCKDEP_MAP_INITIALIZER( \
80 __FILE__ ":" __stringify(__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
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)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
destroy_timer_on_stack(struct timer_list * timer)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 */
timer_pending(const struct timer_list * timer)165 static inline int timer_pending(const struct timer_list * timer)
166 {
167 return timer->entry.pprev != NULL;
168 }
169
170 extern void add_timer_on(struct timer_list *timer, int cpu);
171 extern int del_timer(struct timer_list * timer);
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
186 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
187 extern int del_timer_sync(struct timer_list *timer);
188 #else
189 # define del_timer_sync(t) del_timer(t)
190 #endif
191
192 #define del_singleshot_timer_sync(t) del_timer_sync(t)
193
194 extern void init_timers(void);
195 extern void run_local_timers(void);
196 struct hrtimer;
197 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
198
199 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
200 struct ctl_table;
201
202 extern unsigned int sysctl_timer_migration;
203 int timer_migration_handler(struct ctl_table *table, int write,
204 void __user *buffer, size_t *lenp,
205 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