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#include <linux/timer_types.h>
 11
 12#ifdef CONFIG_LOCKDEP
 13/*
 14 * NB: because we have to copy the lockdep_map, setting the lockdep_map key
 15 * (second argument) here is required, otherwise it could be initialised to
 16 * the copy of the lockdep_map later! We use the pointer to and the string
 17 * "<file>:<line>" as the key resp. the name of the lockdep_map.
 18 */
 19#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)				\
 20	.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
 21#else
 22#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
 23#endif
 24
 25/*
 26 * @TIMER_DEFERRABLE: A deferrable timer will work normally when the
 27 * system is busy, but will not cause a CPU to come out of idle just
 28 * to service it; instead, the timer will be serviced when the CPU
 29 * eventually wakes up with a subsequent non-deferrable timer.
 30 *
 31 * @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
 32 * it's safe to wait for the completion of the running instance from
 33 * IRQ handlers, for example, by calling timer_delete_sync().
 34 *
 35 * Note: The irq disabled callback execution is a special case for
 36 * workqueue locking issues. It's not meant for executing random crap
 37 * with interrupts disabled. Abuse is monitored!
 38 *
 39 * @TIMER_PINNED: A pinned timer will always expire on the CPU on which the
 40 * timer was enqueued. When a particular CPU is required, add_timer_on()
 41 * has to be used. Enqueue via mod_timer() and add_timer() is always done
 42 * on the local CPU.
 43 */
 44#define TIMER_CPUMASK		0x0003FFFF
 45#define TIMER_MIGRATING		0x00040000
 46#define TIMER_BASEMASK		(TIMER_CPUMASK | TIMER_MIGRATING)
 47#define TIMER_DEFERRABLE	0x00080000
 48#define TIMER_PINNED		0x00100000
 49#define TIMER_IRQSAFE		0x00200000
 50#define TIMER_INIT_FLAGS	(TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
 51#define TIMER_ARRAYSHIFT	22
 52#define TIMER_ARRAYMASK		0xFFC00000
 53
 54#define TIMER_TRACE_FLAGMASK	(TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
 55
 56#define __TIMER_INITIALIZER(_function, _flags) {		\
 57		.entry = { .next = TIMER_ENTRY_STATIC },	\
 58		.function = (_function),			\
 59		.flags = (_flags),				\
 60		__TIMER_LOCKDEP_MAP_INITIALIZER(FILE_LINE)	\
 61	}
 62
 63#define DEFINE_TIMER(_name, _function)				\
 64	struct timer_list _name =				\
 65		__TIMER_INITIALIZER(_function, 0)
 66
 67/*
 68 * LOCKDEP and DEBUG timer interfaces.
 69 */
 70void timer_init_key(struct timer_list *timer,
 71		    void (*func)(struct timer_list *), unsigned int flags,
 72		    const char *name, struct lock_class_key *key);
 73
 74#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
 75extern void timer_init_key_on_stack(struct timer_list *timer,
 76				    void (*func)(struct timer_list *),
 77				    unsigned int flags, const char *name,
 78				    struct lock_class_key *key);
 79#else
 80static inline void timer_init_key_on_stack(struct timer_list *timer,
 81					   void (*func)(struct timer_list *),
 82					   unsigned int flags,
 83					   const char *name,
 84					   struct lock_class_key *key)
 85{
 86	timer_init_key(timer, func, flags, name, key);
 87}
 88#endif
 89
 90#ifdef CONFIG_LOCKDEP
 91#define __timer_init(_timer, _fn, _flags)				\
 92	do {								\
 93		static struct lock_class_key __key;			\
 94		timer_init_key((_timer), (_fn), (_flags), #_timer, &__key);\
 95	} while (0)
 96
 97#define __timer_init_on_stack(_timer, _fn, _flags)			\
 98	do {								\
 99		static struct lock_class_key __key;			\
100		timer_init_key_on_stack((_timer), (_fn), (_flags),	\
101					#_timer, &__key);		 \
102	} while (0)
103#else
104#define __timer_init(_timer, _fn, _flags)				\
105	timer_init_key((_timer), (_fn), (_flags), NULL, NULL)
106#define __timer_init_on_stack(_timer, _fn, _flags)			\
107	timer_init_key_on_stack((_timer), (_fn), (_flags), NULL, NULL)
108#endif
109
110/**
111 * timer_setup - prepare a timer for first use
112 * @timer: the timer in question
113 * @callback: the function to call when timer expires
114 * @flags: any TIMER_* flags
115 *
116 * Regular timer initialization should use either DEFINE_TIMER() above,
117 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
118 * be used and must be balanced with a call to timer_destroy_on_stack().
119 */
120#define timer_setup(timer, callback, flags)			\
121	__timer_init((timer), (callback), (flags))
122
123#define timer_setup_on_stack(timer, callback, flags)		\
124	__timer_init_on_stack((timer), (callback), (flags))
125
126#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
127extern void timer_destroy_on_stack(struct timer_list *timer);
128#else
129static inline void timer_destroy_on_stack(struct timer_list *timer) { }
130#endif
131
132#define timer_container_of(var, callback_timer, timer_fieldname)	\
133	container_of(callback_timer, typeof(*var), timer_fieldname)
134
135/**
136 * timer_pending - is a timer pending?
137 * @timer: the timer in question
138 *
139 * timer_pending will tell whether a given timer is currently pending,
140 * or not. Callers must ensure serialization wrt. other operations done
141 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
142 *
143 * Returns: 1 if the timer is pending, 0 if not.
144 */
145static inline int timer_pending(const struct timer_list * timer)
146{
147	return !hlist_unhashed_lockless(&timer->entry);
148}
149
150extern void add_timer_on(struct timer_list *timer, int cpu);
151extern int mod_timer(struct timer_list *timer, unsigned long expires);
152extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
153extern int timer_reduce(struct timer_list *timer, unsigned long expires);
154
155/*
156 * The jiffies value which is added to now, when there is no timer
157 * in the timer wheel:
158 */
159#define TIMER_NEXT_MAX_DELTA	((1UL << 30) - 1)
160
161extern void add_timer(struct timer_list *timer);
162extern void add_timer_local(struct timer_list *timer);
163extern void add_timer_global(struct timer_list *timer);
164
165extern int timer_delete_sync_try(struct timer_list *timer);
166extern int timer_delete_sync(struct timer_list *timer);
167extern int timer_delete(struct timer_list *timer);
168extern int timer_shutdown_sync(struct timer_list *timer);
169extern int timer_shutdown(struct timer_list *timer);
170
171extern void timers_init(void);
172struct hrtimer;
173extern enum hrtimer_restart it_real_fn(struct hrtimer *);
174
175unsigned long __round_jiffies_relative(unsigned long j, int cpu);
176unsigned long round_jiffies(unsigned long j);
177unsigned long round_jiffies_relative(unsigned long j);
178
179unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
180unsigned long round_jiffies_up(unsigned long j);
181unsigned long round_jiffies_up_relative(unsigned long j);
182
183#ifdef CONFIG_HOTPLUG_CPU
184int timers_prepare_cpu(unsigned int cpu);
185int timers_dead_cpu(unsigned int cpu);
186#else
187#define timers_prepare_cpu	NULL
188#define timers_dead_cpu		NULL
189#endif
190
191#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
192extern int tmigr_isolated_exclude_cpumask(struct cpumask *exclude_cpumask);
193#else
194static inline int tmigr_isolated_exclude_cpumask(struct cpumask *exclude_cpumask)
195{
196	return 0;
197}
198#endif
199
200#endif