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_INITIALIZER(_function, _expires, _data, _flags) { \
  68                 .entry = { .next = TIMER_ENTRY_STATIC },        \
  69                 .function = (_function),                        \
  70                 .expires = (_expires),                          \
  71                 .data = (_data),                                \
  72                 .flags = (_flags),                              \
  73                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  74                         __FILE__ ":" __stringify(__LINE__))     \
  75         }
  76
  77 #define TIMER_INITIALIZER(_function, _expires, _data)           \
  78         __TIMER_INITIALIZER((_function), (_expires), (_data), 0)
  79
  80 #define TIMER_PINNED_INITIALIZER(_function, _expires, _data)    \
  81         __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_PINNED)
  82
  83 #define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)  \
  84         __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
  85
  86 #define TIMER_PINNED_DEFERRED_INITIALIZER(_function, _expires, _data)   \
  87         __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE | TIMER_PINNED)
  88
  89 #define DEFINE_TIMER(_name, _function, _expires, _data)         \
  90         struct timer_list _name =                               \
  91                 TIMER_INITIALIZER(_function, _expires, _data)
  92
  93 void init_timer_key(struct timer_list *timer, unsigned int flags,
  94                     const char *name, struct lock_class_key *key);
  95
  96 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  97 extern void init_timer_on_stack_key(struct timer_list *timer,
  98                                     unsigned int flags, const char *name,
  99                                     struct lock_class_key *key);
 100 extern void destroy_timer_on_stack(struct timer_list *timer);
 101 #else
 102 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
 103 static inline void init_timer_on_stack_key(struct timer_list *timer,
 104                                            unsigned int flags, const char *name,
 105                                            struct lock_class_key *key)
 106 {
 107         init_timer_key(timer, flags, name, key);
 108 }
 109 #endif
 110
 111 #ifdef CONFIG_LOCKDEP
 112 #define __init_timer(_timer, _flags)                                    \
 113         do {                                                            \
 114                 static struct lock_class_key __key;                     \
 115                 init_timer_key((_timer), (_flags), #_timer, &__key);    \
 116         } while (0)
 117
 118 #define __init_timer_on_stack(_timer, _flags)                           \
 119         do {                                                            \
 120                 static struct lock_class_key __key;                     \
 121                 init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 122         } while (0)
 123 #else
 124 #define __init_timer(_timer, _flags)                                    \
 125         init_timer_key((_timer), (_flags), NULL, NULL)
 126 #define __init_timer_on_stack(_timer, _flags)                           \
 127         init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 128 #endif
 129
 130 #define init_timer(timer)                                               \
 131         __init_timer((timer), 0)
 132 #define init_timer_pinned(timer)                                        \
 133         __init_timer((timer), TIMER_PINNED)
 134 #define init_timer_deferrable(timer)                                    \
 135         __init_timer((timer), TIMER_DEFERRABLE)
 136 #define init_timer_pinned_deferrable(timer)                             \
 137         __init_timer((timer), TIMER_DEFERRABLE | TIMER_PINNED)
 138 #define init_timer_on_stack(timer)                                      \
 139         __init_timer_on_stack((timer), 0)
 140
 141 #define __setup_timer(_timer, _fn, _data, _flags)                       \
 142         do {                                                            \
 143                 __init_timer((_timer), (_flags));                       \
 144                 (_timer)->function = (_fn);                             \
 145                 (_timer)->data = (_data);                               \
 146         } while (0)
 147
 148 #define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 149         do {                                                            \
 150                 __init_timer_on_stack((_timer), (_flags));              \
 151                 (_timer)->function = (_fn);                             \
 152                 (_timer)->data = (_data);                               \
 153         } while (0)
 154
 155 #define setup_timer(timer, fn, data)                                    \
 156         __setup_timer((timer), (fn), (data), 0)
 157 #define setup_pinned_timer(timer, fn, data)                             \
 158         __setup_timer((timer), (fn), (data), TIMER_PINNED)
 159 #define setup_deferrable_timer(timer, fn, data)                         \
 160         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)
 161 #define setup_pinned_deferrable_timer(timer, fn, data)                  \
 162         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 163 #define setup_timer_on_stack(timer, fn, data)                           \
 164         __setup_timer_on_stack((timer), (fn), (data), 0)
 165 #define setup_pinned_timer_on_stack(timer, fn, data)                    \
 166         __setup_timer_on_stack((timer), (fn), (data), TIMER_PINNED)
 167 #define setup_deferrable_timer_on_stack(timer, fn, data)                \
 168         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 169 #define setup_pinned_deferrable_timer_on_stack(timer, fn, data)         \
 170         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 171
 172 #define TIMER_DATA_TYPE         unsigned long
 173 #define TIMER_FUNC_TYPE         void (*)(TIMER_DATA_TYPE)
 174
 175 static inline void timer_setup(struct timer_list *timer,
 176                                void (*callback)(struct timer_list *),
 177                                unsigned int flags)
 178 {
 179         __setup_timer(timer, (TIMER_FUNC_TYPE)callback,
 180                       (TIMER_DATA_TYPE)timer, flags);
 181 }
 182
 183 #define from_timer(var, callback_timer, timer_fieldname) \
 184         container_of(callback_timer, typeof(*var), timer_fieldname)
 185
 186 /**
 187  * timer_pending - is a timer pending?
 188  * @timer: the timer in question
 189  *
 190  * timer_pending will tell whether a given timer is currently pending,
 191  * or not. Callers must ensure serialization wrt. other operations done
 192  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 193  *
 194  * return value: 1 if the timer is pending, 0 if not.
 195  */
 196 static inline int timer_pending(const struct timer_list * timer)
 197 {
 198         return timer->entry.pprev != NULL;
 199 }
 200
 201 extern void add_timer_on(struct timer_list *timer, int cpu);
 202 extern int del_timer(struct timer_list * timer);
 203 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 204 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 205
 206 /*
 207  * The jiffies value which is added to now, when there is no timer
 208  * in the timer wheel:
 209  */
 210 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 211
 212 extern void add_timer(struct timer_list *timer);
 213
 214 extern int try_to_del_timer_sync(struct timer_list *timer);
 215
 216 #ifdef CONFIG_SMP
 217   extern int del_timer_sync(struct timer_list *timer);
 218 #else
 219 # define del_timer_sync(t)              del_timer(t)
 220 #endif
 221
 222 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 223
 224 extern void init_timers(void);
 225 extern void run_local_timers(void);
 226 struct hrtimer;
 227 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 228
 229 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 230 struct ctl_table;
 231
 232 extern unsigned int sysctl_timer_migration;
 233 int timer_migration_handler(struct ctl_table *table, int write,
 234                             void __user *buffer, size_t *lenp,
 235                             loff_t *ppos);
 236 #endif
 237
 238 unsigned long __round_jiffies(unsigned long j, int cpu);
 239 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 240 unsigned long round_jiffies(unsigned long j);
 241 unsigned long round_jiffies_relative(unsigned long j);
 242
 243 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 244 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 245 unsigned long round_jiffies_up(unsigned long j);
 246 unsigned long round_jiffies_up_relative(unsigned long j);
 247
 248 #ifdef CONFIG_HOTPLUG_CPU
 249 int timers_dead_cpu(unsigned int cpu);
 250 #else
 251 #define timers_dead_cpu NULL
 252 #endif
 253
 254 #endif