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 #include <linux/android_kabi.h>
11
12 struct timer_list {
13 /*
14 * All fields that change during normal runtime grouped to the
15 * same cacheline
16 */
17 struct hlist_node entry;
18 unsigned long expires;
19 void (*function)(struct timer_list *);
20 u32 flags;
21
22 #ifdef CONFIG_LOCKDEP
23 struct lockdep_map lockdep_map;
24 #endif
25
26 ANDROID_KABI_RESERVE(1);
27 ANDROID_KABI_RESERVE(2);
28 };
29
30 #ifdef CONFIG_LOCKDEP
31 /*
32 * NB: because we have to copy the lockdep_map, setting the lockdep_map key
33 * (second argument) here is required, otherwise it could be initialised to
34 * the copy of the lockdep_map later! We use the pointer to and the string
35 * "<file>:<line>" as the key resp. the name of the lockdep_map.
36 */
37 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
38 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
39 #else
40 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
41 #endif
42
43 /**
44 * @TIMER_DEFERRABLE: A deferrable timer will work normally when the
45 * system is busy, but will not cause a CPU to come out of idle just
46 * to service it; instead, the timer will be serviced when the CPU
47 * eventually wakes up with a subsequent non-deferrable timer.
48 *
49 * @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
50 * it's safe to wait for the completion of the running instance from
51 * IRQ handlers, for example, by calling del_timer_sync().
52 *
53 * Note: The irq disabled callback execution is a special case for
54 * workqueue locking issues. It's not meant for executing random crap
55 * with interrupts disabled. Abuse is monitored!
56 *
57 * @TIMER_PINNED: A pinned timer will not be affected by any timer
58 * placement heuristics (like, NOHZ) and will always expire on the CPU
59 * on which the timer was enqueued.
60 *
61 * Note: Because enqueuing of timers can migrate the timer from one
62 * CPU to another, pinned timers are not guaranteed to stay on the
63 * initialy selected CPU. They move to the CPU on which the enqueue
64 * function is invoked via mod_timer() or add_timer(). If the timer
65 * should be placed on a particular CPU, then add_timer_on() has to be
66 * used.
67 */
68 #define TIMER_CPUMASK 0x0003FFFF
69 #define TIMER_MIGRATING 0x00040000
70 #define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
71 #define TIMER_DEFERRABLE 0x00080000
72 #define TIMER_PINNED 0x00100000
73 #define TIMER_IRQSAFE 0x00200000
74 #define TIMER_ARRAYSHIFT 22
75 #define TIMER_ARRAYMASK 0xFFC00000
76
77 #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
78
79 #define __TIMER_INITIALIZER(_function, _flags) { \
80 .entry = { .next = TIMER_ENTRY_STATIC }, \
81 .function = (_function), \
82 .flags = (_flags), \
83 __TIMER_LOCKDEP_MAP_INITIALIZER( \
84 __FILE__ ":" __stringify(__LINE__)) \
85 }
86
87 #define DEFINE_TIMER(_name, _function) \
88 struct timer_list _name = \
89 __TIMER_INITIALIZER(_function, 0)
90
91 /*
92 * LOCKDEP and DEBUG timer interfaces.
93 */
94 void init_timer_key(struct timer_list *timer,
95 void (*func)(struct timer_list *), unsigned int flags,
96 const char *name, struct lock_class_key *key);
97
98 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
99 extern void init_timer_on_stack_key(struct timer_list *timer,
100 void (*func)(struct timer_list *),
101 unsigned int flags, const char *name,
102 struct lock_class_key *key);
103 #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)104 static inline void init_timer_on_stack_key(struct timer_list *timer,
105 void (*func)(struct timer_list *),
106 unsigned int flags,
107 const char *name,
108 struct lock_class_key *key)
109 {
110 init_timer_key(timer, func, flags, name, key);
111 }
112 #endif
113
114 #ifdef CONFIG_LOCKDEP
115 #define __init_timer(_timer, _fn, _flags) \
116 do { \
117 static struct lock_class_key __key; \
118 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
119 } while (0)
120
121 #define __init_timer_on_stack(_timer, _fn, _flags) \
122 do { \
123 static struct lock_class_key __key; \
124 init_timer_on_stack_key((_timer), (_fn), (_flags), \
125 #_timer, &__key); \
126 } while (0)
127 #else
128 #define __init_timer(_timer, _fn, _flags) \
129 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
130 #define __init_timer_on_stack(_timer, _fn, _flags) \
131 init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
132 #endif
133
134 /**
135 * timer_setup - prepare a timer for first use
136 * @timer: the timer in question
137 * @callback: the function to call when timer expires
138 * @flags: any TIMER_* flags
139 *
140 * Regular timer initialization should use either DEFINE_TIMER() above,
141 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
142 * be used and must be balanced with a call to destroy_timer_on_stack().
143 */
144 #define timer_setup(timer, callback, flags) \
145 __init_timer((timer), (callback), (flags))
146
147 #define timer_setup_on_stack(timer, callback, flags) \
148 __init_timer_on_stack((timer), (callback), (flags))
149
150 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
151 extern void destroy_timer_on_stack(struct timer_list *timer);
152 #else
destroy_timer_on_stack(struct timer_list * timer)153 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
154 #endif
155
156 #define from_timer(var, callback_timer, timer_fieldname) \
157 container_of(callback_timer, typeof(*var), timer_fieldname)
158
159 /**
160 * timer_pending - is a timer pending?
161 * @timer: the timer in question
162 *
163 * timer_pending will tell whether a given timer is currently pending,
164 * or not. Callers must ensure serialization wrt. other operations done
165 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
166 *
167 * return value: 1 if the timer is pending, 0 if not.
168 */
timer_pending(const struct timer_list * timer)169 static inline int timer_pending(const struct timer_list * timer)
170 {
171 return timer->entry.pprev != NULL;
172 }
173
174 extern void add_timer_on(struct timer_list *timer, int cpu);
175 extern int del_timer(struct timer_list * timer);
176 extern int mod_timer(struct timer_list *timer, unsigned long expires);
177 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
178 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
179
180 /*
181 * The jiffies value which is added to now, when there is no timer
182 * in the timer wheel:
183 */
184 #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
185
186 extern void add_timer(struct timer_list *timer);
187
188 extern int try_to_del_timer_sync(struct timer_list *timer);
189 extern int del_timer_sync(struct timer_list *timer);
190
191 #define del_singleshot_timer_sync(t) del_timer_sync(t)
192
193 extern void init_timers(void);
194 extern void run_local_timers(void);
195 struct hrtimer;
196 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
197
198 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
199 struct ctl_table;
200
201 extern unsigned int sysctl_timer_migration;
202 int timer_migration_handler(struct ctl_table *table, int write,
203 void __user *buffer, size_t *lenp,
204 loff_t *ppos);
205 #endif
206
207 unsigned long __round_jiffies(unsigned long j, int cpu);
208 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
209 unsigned long round_jiffies(unsigned long j);
210 unsigned long round_jiffies_relative(unsigned long j);
211
212 unsigned long __round_jiffies_up(unsigned long j, int cpu);
213 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
214 unsigned long round_jiffies_up(unsigned long j);
215 unsigned long round_jiffies_up_relative(unsigned long j);
216
217 #ifdef CONFIG_HOTPLUG_CPU
218 int timers_prepare_cpu(unsigned int cpu);
219 int timers_dead_cpu(unsigned int cpu);
220 #else
221 #define timers_prepare_cpu NULL
222 #define timers_dead_cpu NULL
223 #endif
224
225 #endif
226