include/linux/timer.h

   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 tvec_base;
  12
  13 struct timer_list {
  14         /*
  15          * All fields that change during normal runtime grouped to the
  16          * same cacheline
  17          */
  18         struct hlist_node       entry;
  19         unsigned long           expires;
  20         void                    (*function)(unsigned long);
  21         unsigned long           data;
  22         u32                     flags;
  23
  24 #ifdef CONFIG_LOCKDEP
  25         struct lockdep_map      lockdep_map;
  26 #endif
  27 };
  28
  29 #ifdef CONFIG_LOCKDEP
  30 /*
  31  * NB: because we have to copy the lockdep_map, setting the lockdep_map key
  32  * (second argument) here is required, otherwise it could be initialised to
  33  * the copy of the lockdep_map later! We use the pointer to and the string
  34  * "<file>:<line>" as the key resp. the name of the lockdep_map.
  35  */
  36 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
  37         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  38 #else
  39 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  40 #endif
  41
  42 /*
  43  * A deferrable timer will work normally when the system is busy, but
  44  * will not cause a CPU to come out of idle just to service it; instead,
  45  * the timer will be serviced when the CPU eventually wakes up with a
  46  * subsequent non-deferrable timer.
  47  *
  48  * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
  49  * the completion of the running instance from IRQ handlers, for example,
  50  * by calling del_timer_sync().
  51  *
  52  * Note: The irq disabled callback execution is a special case for
  53  * workqueue locking issues. It's not meant for executing random crap
  54  * with interrupts disabled. Abuse is monitored!
  55  */
  56 #define TIMER_CPUMASK           0x0003FFFF
  57 #define TIMER_MIGRATING         0x00040000
  58 #define TIMER_BASEMASK          (TIMER_CPUMASK | TIMER_MIGRATING)
  59 #define TIMER_DEFERRABLE        0x00080000
  60 #define TIMER_PINNED            0x00100000
  61 #define TIMER_IRQSAFE           0x00200000
  62 #define TIMER_ARRAYSHIFT        22
  63 #define TIMER_ARRAYMASK         0xFFC00000
  64
  65 #define TIMER_TRACE_FLAGMASK    (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
  66
  67 #define TIMER_DATA_TYPE         unsigned long
  68 #define TIMER_FUNC_TYPE         void (*)(TIMER_DATA_TYPE)
  69
  70 #define __TIMER_INITIALIZER(_function, _data, _flags) {         \
  71                 .entry = { .next = TIMER_ENTRY_STATIC },        \
  72                 .function = (_function),                        \
  73                 .data = (_data),                                \
  74                 .flags = (_flags),                              \
  75                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  76                         __FILE__ ":" __stringify(__LINE__))     \
  77         }
  78
  79 #define DEFINE_TIMER(_name, _function)                          \
  80         struct timer_list _name =                               \
  81                 __TIMER_INITIALIZER((TIMER_FUNC_TYPE)_function, 0, 0)
  82
  83 void init_timer_key(struct timer_list *timer, unsigned int flags,
  84                     const char *name, struct lock_class_key *key);
  85
  86 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  87 extern void init_timer_on_stack_key(struct timer_list *timer,
  88                                     unsigned int flags, const char *name,
  89                                     struct lock_class_key *key);
  90 extern void destroy_timer_on_stack(struct timer_list *timer);
  91 #else
  92 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  93 static inline void init_timer_on_stack_key(struct timer_list *timer,
  94                                            unsigned int flags, const char *name,
  95                                            struct lock_class_key *key)
  96 {
  97         init_timer_key(timer, flags, name, key);
  98 }
  99 #endif
 100
 101 #ifdef CONFIG_LOCKDEP
 102 #define __init_timer(_timer, _flags)                                    \
 103         do {                                                            \
 104                 static struct lock_class_key __key;                     \
 105                 init_timer_key((_timer), (_flags), #_timer, &__key);    \
 106         } while (0)
 107
 108 #define __init_timer_on_stack(_timer, _flags)                           \
 109         do {                                                            \
 110                 static struct lock_class_key __key;                     \
 111                 init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 112         } while (0)
 113 #else
 114 #define __init_timer(_timer, _flags)                                    \
 115         init_timer_key((_timer), (_flags), NULL, NULL)
 116 #define __init_timer_on_stack(_timer, _flags)                           \
 117         init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 118 #endif
 119
 120 #define __setup_timer(_timer, _fn, _data, _flags)                       \
 121         do {                                                            \
 122                 __init_timer((_timer), (_flags));                       \
 123                 (_timer)->function = (_fn);                             \
 124                 (_timer)->data = (_data);                               \
 125         } while (0)
 126
 127 #define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 128         do {                                                            \
 129                 __init_timer_on_stack((_timer), (_flags));              \
 130                 (_timer)->function = (_fn);                             \
 131                 (_timer)->data = (_data);                               \
 132         } while (0)
 133
 134 #ifndef CONFIG_LOCKDEP
 135 static inline void timer_setup(struct timer_list *timer,
 136                                void (*callback)(struct timer_list *),
 137                                unsigned int flags)
 138 {
 139         __setup_timer(timer, (TIMER_FUNC_TYPE)callback,
 140                       (TIMER_DATA_TYPE)timer, flags);
 141 }
 142
 143 static inline void timer_setup_on_stack(struct timer_list *timer,
 144                                void (*callback)(struct timer_list *),
 145                                unsigned int flags)
 146 {
 147         __setup_timer_on_stack(timer, (TIMER_FUNC_TYPE)callback,
 148                                (TIMER_DATA_TYPE)timer, flags);
 149 }
 150 #else
 151 /*
 152  * Under LOCKDEP, the timer lock_class_key (set up in __init_timer) needs
 153  * to be tied to the caller's context, so an inline (above) won't work. We
 154  * do want to keep the inline for argument type checking, though.
 155  */
 156 # define timer_setup(timer, callback, flags)                            \
 157                 __setup_timer((timer), (TIMER_FUNC_TYPE)(callback),     \
 158                               (TIMER_DATA_TYPE)(timer), (flags))
 159 # define timer_setup_on_stack(timer, callback, flags)                   \
 160                 __setup_timer_on_stack((timer),                         \
 161                                        (TIMER_FUNC_TYPE)(callback),     \
 162                                        (TIMER_DATA_TYPE)(timer), (flags))
 163 #endif
 164
 165 #define from_timer(var, callback_timer, timer_fieldname) \
 166         container_of(callback_timer, typeof(*var), timer_fieldname)
 167
 168 /**
 169  * timer_pending - is a timer pending?
 170  * @timer: the timer in question
 171  *
 172  * timer_pending will tell whether a given timer is currently pending,
 173  * or not. Callers must ensure serialization wrt. other operations done
 174  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 175  *
 176  * return value: 1 if the timer is pending, 0 if not.
 177  */
 178 static inline int timer_pending(const struct timer_list * timer)
 179 {
 180         return timer->entry.pprev != NULL;
 181 }
 182
 183 extern void add_timer_on(struct timer_list *timer, int cpu);
 184 extern int del_timer(struct timer_list * timer);
 185 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 186 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 187 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
 188
 189 /*
 190  * The jiffies value which is added to now, when there is no timer
 191  * in the timer wheel:
 192  */
 193 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 194
 195 extern void add_timer(struct timer_list *timer);
 196
 197 extern int try_to_del_timer_sync(struct timer_list *timer);
 198
 199 #ifdef CONFIG_SMP
 200   extern int del_timer_sync(struct timer_list *timer);
 201 #else
 202 # define del_timer_sync(t)              del_timer(t)
 203 #endif
 204
 205 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 206
 207 extern void init_timers(void);
 208 extern void run_local_timers(void);
 209 struct hrtimer;
 210 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 211
 212 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 213 struct ctl_table;
 214
 215 extern unsigned int sysctl_timer_migration;
 216 int timer_migration_handler(struct ctl_table *table, int write,
 217                             void __user *buffer, size_t *lenp,
 218                             loff_t *ppos);
 219 #endif
 220
 221 unsigned long __round_jiffies(unsigned long j, int cpu);
 222 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 223 unsigned long round_jiffies(unsigned long j);
 224 unsigned long round_jiffies_relative(unsigned long j);
 225
 226 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 227 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 228 unsigned long round_jiffies_up(unsigned long j);
 229 unsigned long round_jiffies_up_relative(unsigned long j);
 230
 231 #ifdef CONFIG_HOTPLUG_CPU
 232 int timers_dead_cpu(unsigned int cpu);
 233 #else
 234 #define timers_dead_cpu NULL
 235 #endif
 236
 237 #endif