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