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 init_timer(timer)                                               \
 121         __init_timer((timer), 0)
 122
 123 #define __setup_timer(_timer, _fn, _data, _flags)                       \
 124         do {                                                            \
 125                 __init_timer((_timer), (_flags));                       \
 126                 (_timer)->function = (_fn);                             \
 127                 (_timer)->data = (_data);                               \
 128         } while (0)
 129
 130 #define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 131         do {                                                            \
 132                 __init_timer_on_stack((_timer), (_flags));              \
 133                 (_timer)->function = (_fn);                             \
 134                 (_timer)->data = (_data);                               \
 135         } while (0)
 136
 137 #define setup_timer(timer, fn, data)                                    \
 138         __setup_timer((timer), (fn), (data), 0)
 139 #define setup_pinned_timer(timer, fn, data)                             \
 140         __setup_timer((timer), (fn), (data), TIMER_PINNED)
 141 #define setup_deferrable_timer(timer, fn, data)                         \
 142         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)
 143 #define setup_pinned_deferrable_timer(timer, fn, data)                  \
 144         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 145 #define setup_timer_on_stack(timer, fn, data)                           \
 146         __setup_timer_on_stack((timer), (fn), (data), 0)
 147 #define setup_pinned_timer_on_stack(timer, fn, data)                    \
 148         __setup_timer_on_stack((timer), (fn), (data), TIMER_PINNED)
 149 #define setup_deferrable_timer_on_stack(timer, fn, data)                \
 150         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 151 #define setup_pinned_deferrable_timer_on_stack(timer, fn, data)         \
 152         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 153
 154 #ifndef CONFIG_LOCKDEP
 155 static inline void timer_setup(struct timer_list *timer,
 156                                void (*callback)(struct timer_list *),
 157                                unsigned int flags)
 158 {
 159         __setup_timer(timer, (TIMER_FUNC_TYPE)callback,
 160                       (TIMER_DATA_TYPE)timer, flags);
 161 }
 162
 163 static inline void timer_setup_on_stack(struct timer_list *timer,
 164                                void (*callback)(struct timer_list *),
 165                                unsigned int flags)
 166 {
 167         __setup_timer_on_stack(timer, (TIMER_FUNC_TYPE)callback,
 168                                (TIMER_DATA_TYPE)timer, flags);
 169 }
 170 #else
 171 /*
 172  * Under LOCKDEP, the timer lock_class_key (set up in __init_timer) needs
 173  * to be tied to the caller's context, so an inline (above) won't work. We
 174  * do want to keep the inline for argument type checking, though.
 175  */
 176 # define timer_setup(timer, callback, flags)                            \
 177                 __setup_timer((timer), (TIMER_FUNC_TYPE)(callback),     \
 178                               (TIMER_DATA_TYPE)(timer), (flags))
 179 # define timer_setup_on_stack(timer, callback, flags)                   \
 180                 __setup_timer_on_stack((timer),                         \
 181                                        (TIMER_FUNC_TYPE)(callback),     \
 182                                        (TIMER_DATA_TYPE)(timer), (flags))
 183 #endif
 184
 185 #define from_timer(var, callback_timer, timer_fieldname) \
 186         container_of(callback_timer, typeof(*var), timer_fieldname)
 187
 188 /**
 189  * timer_pending - is a timer pending?
 190  * @timer: the timer in question
 191  *
 192  * timer_pending will tell whether a given timer is currently pending,
 193  * or not. Callers must ensure serialization wrt. other operations done
 194  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 195  *
 196  * return value: 1 if the timer is pending, 0 if not.
 197  */
 198 static inline int timer_pending(const struct timer_list * timer)
 199 {
 200         return timer->entry.pprev != NULL;
 201 }
 202
 203 extern void add_timer_on(struct timer_list *timer, int cpu);
 204 extern int del_timer(struct timer_list * timer);
 205 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 206 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 207 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
 208
 209 /*
 210  * The jiffies value which is added to now, when there is no timer
 211  * in the timer wheel:
 212  */
 213 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 214
 215 extern void add_timer(struct timer_list *timer);
 216
 217 extern int try_to_del_timer_sync(struct timer_list *timer);
 218
 219 #ifdef CONFIG_SMP
 220   extern int del_timer_sync(struct timer_list *timer);
 221 #else
 222 # define del_timer_sync(t)              del_timer(t)
 223 #endif
 224
 225 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 226
 227 extern void init_timers(void);
 228 extern void run_local_timers(void);
 229 struct hrtimer;
 230 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 231
 232 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 233 struct ctl_table;
 234
 235 extern unsigned int sysctl_timer_migration;
 236 int timer_migration_handler(struct ctl_table *table, int write,
 237                             void __user *buffer, size_t *lenp,
 238                             loff_t *ppos);
 239 #endif
 240
 241 unsigned long __round_jiffies(unsigned long j, int cpu);
 242 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 243 unsigned long round_jiffies(unsigned long j);
 244 unsigned long round_jiffies_relative(unsigned long j);
 245
 246 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 247 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 248 unsigned long round_jiffies_up(unsigned long j);
 249 unsigned long round_jiffies_up_relative(unsigned long j);
 250
 251 #ifdef CONFIG_HOTPLUG_CPU
 252 int timers_dead_cpu(unsigned int cpu);
 253 #else
 254 #define timers_dead_cpu NULL
 255 #endif
 256
 257 #endif