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_INIT_FLAGS (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
75 #define TIMER_ARRAYSHIFT 22
76 #define TIMER_ARRAYMASK 0xFFC00000
77
78 #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
79
80 #define __TIMER_INITIALIZER(_function, _flags) { \
81 .entry = { .next = TIMER_ENTRY_STATIC }, \
82 .function = (_function), \
83 .flags = (_flags), \
84 __TIMER_LOCKDEP_MAP_INITIALIZER( \
85 __FILE__ ":" __stringify(__LINE__)) \
86 }
87
88 #define DEFINE_TIMER(_name, _function) \
89 struct timer_list _name = \
90 __TIMER_INITIALIZER(_function, 0)
91
92 /*
93 * LOCKDEP and DEBUG timer interfaces.
94 */
95 void init_timer_key(struct timer_list *timer,
96 void (*func)(struct timer_list *), unsigned int flags,
97 const char *name, struct lock_class_key *key);
98
99 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
100 extern void init_timer_on_stack_key(struct timer_list *timer,
101 void (*func)(struct timer_list *),
102 unsigned int flags, const char *name,
103 struct lock_class_key *key);
104 #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)105 static inline void init_timer_on_stack_key(struct timer_list *timer,
106 void (*func)(struct timer_list *),
107 unsigned int flags,
108 const char *name,
109 struct lock_class_key *key)
110 {
111 init_timer_key(timer, func, flags, name, key);
112 }
113 #endif
114
115 #ifdef CONFIG_LOCKDEP
116 #define __init_timer(_timer, _fn, _flags) \
117 do { \
118 static struct lock_class_key __key; \
119 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
120 } while (0)
121
122 #define __init_timer_on_stack(_timer, _fn, _flags) \
123 do { \
124 static struct lock_class_key __key; \
125 init_timer_on_stack_key((_timer), (_fn), (_flags), \
126 #_timer, &__key); \
127 } while (0)
128 #else
129 #define __init_timer(_timer, _fn, _flags) \
130 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
131 #define __init_timer_on_stack(_timer, _fn, _flags) \
132 init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
133 #endif
134
135 /**
136 * timer_setup - prepare a timer for first use
137 * @timer: the timer in question
138 * @callback: the function to call when timer expires
139 * @flags: any TIMER_* flags
140 *
141 * Regular timer initialization should use either DEFINE_TIMER() above,
142 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
143 * be used and must be balanced with a call to destroy_timer_on_stack().
144 */
145 #define timer_setup(timer, callback, flags) \
146 __init_timer((timer), (callback), (flags))
147
148 #define timer_setup_on_stack(timer, callback, flags) \
149 __init_timer_on_stack((timer), (callback), (flags))
150
151 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
152 extern void destroy_timer_on_stack(struct timer_list *timer);
153 #else
destroy_timer_on_stack(struct timer_list * timer)154 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
155 #endif
156
157 #define from_timer(var, callback_timer, timer_fieldname) \
158 container_of(callback_timer, typeof(*var), timer_fieldname)
159
160 /**
161 * timer_pending - is a timer pending?
162 * @timer: the timer in question
163 *
164 * timer_pending will tell whether a given timer is currently pending,
165 * or not. Callers must ensure serialization wrt. other operations done
166 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
167 *
168 * return value: 1 if the timer is pending, 0 if not.
169 */
timer_pending(const struct timer_list * timer)170 static inline int timer_pending(const struct timer_list * timer)
171 {
172 return !hlist_unhashed_lockless(&timer->entry);
173 }
174
175 extern void add_timer_on(struct timer_list *timer, int cpu);
176 extern int del_timer(struct timer_list * timer);
177 extern int mod_timer(struct timer_list *timer, unsigned long expires);
178 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
179 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
180
181 /*
182 * The jiffies value which is added to now, when there is no timer
183 * in the timer wheel:
184 */
185 #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
186
187 extern void add_timer(struct timer_list *timer);
188
189 extern int try_to_del_timer_sync(struct timer_list *timer);
190
191 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
192 extern int del_timer_sync(struct timer_list *timer);
193 #else
194 # define del_timer_sync(t) del_timer(t)
195 #endif
196
197 #define del_singleshot_timer_sync(t) del_timer_sync(t)
198
199 extern void init_timers(void);
200 struct hrtimer;
201 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
202
203 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
204 struct ctl_table;
205
206 extern unsigned int sysctl_timer_migration;
207 int timer_migration_handler(struct ctl_table *table, int write,
208 void *buffer, size_t *lenp, loff_t *ppos);
209 #endif
210
211 unsigned long __round_jiffies(unsigned long j, int cpu);
212 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
213 unsigned long round_jiffies(unsigned long j);
214 unsigned long round_jiffies_relative(unsigned long j);
215
216 unsigned long __round_jiffies_up(unsigned long j, int cpu);
217 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
218 unsigned long round_jiffies_up(unsigned long j);
219 unsigned long round_jiffies_up_relative(unsigned long j);
220
221 #ifdef CONFIG_HOTPLUG_CPU
222 int timers_prepare_cpu(unsigned int cpu);
223 int timers_dead_cpu(unsigned int cpu);
224 #else
225 #define timers_prepare_cpu NULL
226 #define timers_dead_cpu NULL
227 #endif
228
229 #endif
230