1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * tick internal variable and functions used by low/high res code
4 */
5#include <linux/hrtimer.h>
6#include <linux/tick.h>
7
8#include "timekeeping.h"
9#include "tick-sched.h"
10
11struct timer_events {
12 u64 local;
13 u64 global;
14};
15
16#ifdef CONFIG_GENERIC_CLOCKEVENTS
17
18# define TICK_DO_TIMER_NONE -1
19# define TICK_DO_TIMER_BOOT -2
20
21DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
22extern ktime_t tick_next_period;
23extern int tick_do_timer_cpu __read_mostly;
24
25extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
26extern void tick_handle_periodic(struct clock_event_device *dev);
27extern void tick_check_new_device(struct clock_event_device *dev);
28extern void tick_offline_cpu(unsigned int cpu);
29extern void tick_shutdown(void);
30extern void tick_suspend(void);
31extern void tick_resume(void);
32extern bool tick_check_replacement(struct clock_event_device *curdev,
33 struct clock_event_device *newdev);
34extern void tick_install_replacement(struct clock_event_device *dev);
35extern int tick_is_oneshot_available(void);
36extern struct tick_device *tick_get_device(int cpu);
37
38extern int clockevents_tick_resume(struct clock_event_device *dev);
39/* Check, if the device is functional or a dummy for broadcast */
40static inline int tick_device_is_functional(struct clock_event_device *dev)
41{
42 return !(dev->features & CLOCK_EVT_FEAT_DUMMY);
43}
44
45static inline enum clock_event_state clockevent_get_state(struct clock_event_device *dev)
46{
47 return dev->state_use_accessors;
48}
49
50static inline void clockevent_set_state(struct clock_event_device *dev,
51 enum clock_event_state state)
52{
53 dev->state_use_accessors = state;
54}
55
56extern void clockevents_shutdown(struct clock_event_device *dev);
57extern void clockevents_exchange_device(struct clock_event_device *old,
58 struct clock_event_device *new);
59extern void clockevents_switch_state(struct clock_event_device *dev,
60 enum clock_event_state state);
61extern int clockevents_program_event(struct clock_event_device *dev,
62 ktime_t expires, bool force);
63extern void clockevents_handle_noop(struct clock_event_device *dev);
64extern int __clockevents_update_freq(struct clock_event_device *dev, u32 freq);
65
66/* Broadcasting support */
67# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
68extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu);
69extern void tick_install_broadcast_device(struct clock_event_device *dev, int cpu);
70extern int tick_is_broadcast_device(struct clock_event_device *dev);
71extern void tick_suspend_broadcast(void);
72extern void tick_resume_broadcast(void);
73extern bool tick_resume_check_broadcast(void);
74extern void tick_broadcast_init(void);
75extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast);
76extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq);
77extern struct tick_device *tick_get_broadcast_device(void);
78extern struct cpumask *tick_get_broadcast_mask(void);
79extern const struct clock_event_device *tick_get_wakeup_device(int cpu);
80# else /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST: */
81static inline void tick_install_broadcast_device(struct clock_event_device *dev, int cpu) { }
82static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; }
83static inline int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { return 0; }
84static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { }
85static inline void tick_suspend_broadcast(void) { }
86static inline void tick_resume_broadcast(void) { }
87static inline bool tick_resume_check_broadcast(void) { return false; }
88static inline void tick_broadcast_init(void) { }
89static inline int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq) { return -ENODEV; }
90
91/* Set the periodic handler in non broadcast mode */
92static inline void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
93{
94 dev->event_handler = tick_handle_periodic;
95}
96# endif /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST */
97
98#else /* !GENERIC_CLOCKEVENTS: */
99static inline void tick_suspend(void) { }
100static inline void tick_resume(void) { }
101#endif /* !GENERIC_CLOCKEVENTS */
102
103/* Oneshot related functions */
104#ifdef CONFIG_TICK_ONESHOT
105extern void tick_setup_oneshot(struct clock_event_device *newdev,
106 void (*handler)(struct clock_event_device *),
107 ktime_t nextevt);
108extern int tick_program_event(ktime_t expires, int force);
109extern void tick_oneshot_notify(void);
110extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
111extern void tick_resume_oneshot(void);
112static inline bool tick_oneshot_possible(void) { return true; }
113extern int tick_oneshot_mode_active(void);
114extern void tick_clock_notify(void);
115extern int tick_check_oneshot_change(int allow_nohz);
116extern int tick_init_highres(void);
117#else /* !CONFIG_TICK_ONESHOT: */
118static inline
119void tick_setup_oneshot(struct clock_event_device *newdev,
120 void (*handler)(struct clock_event_device *),
121 ktime_t nextevt) { BUG(); }
122static inline void tick_resume_oneshot(void) { BUG(); }
123static inline int tick_program_event(ktime_t expires, int force) { return 0; }
124static inline void tick_oneshot_notify(void) { }
125static inline bool tick_oneshot_possible(void) { return false; }
126static inline int tick_oneshot_mode_active(void) { return 0; }
127static inline void tick_clock_notify(void) { }
128static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
129#endif /* !CONFIG_TICK_ONESHOT */
130
131/* Functions related to oneshot broadcasting */
132#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
133extern void tick_broadcast_switch_to_oneshot(void);
134extern int tick_broadcast_oneshot_active(void);
135extern void tick_check_oneshot_broadcast_this_cpu(void);
136bool tick_broadcast_oneshot_available(void);
137extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
138#else /* !(BROADCAST && ONESHOT): */
139static inline void tick_broadcast_switch_to_oneshot(void) { }
140static inline int tick_broadcast_oneshot_active(void) { return 0; }
141static inline void tick_check_oneshot_broadcast_this_cpu(void) { }
142static inline bool tick_broadcast_oneshot_available(void) { return tick_oneshot_possible(); }
143#endif /* !(BROADCAST && ONESHOT) */
144
145#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_HOTPLUG_CPU)
146extern void tick_broadcast_offline(unsigned int cpu);
147#else
148static inline void tick_broadcast_offline(unsigned int cpu) { }
149#endif
150
151/* NO_HZ_FULL internal */
152#ifdef CONFIG_NO_HZ_FULL
153extern void tick_nohz_init(void);
154# else
155static inline void tick_nohz_init(void) { }
156#endif
157
158#ifdef CONFIG_NO_HZ_COMMON
159extern unsigned long tick_nohz_active;
160extern void timers_update_nohz(void);
161extern u64 get_jiffies_update(unsigned long *basej);
162# ifdef CONFIG_SMP
163extern struct static_key_false timers_migration_enabled;
164extern void fetch_next_timer_interrupt_remote(unsigned long basej, u64 basem,
165 struct timer_events *tevt,
166 unsigned int cpu);
167extern void timer_lock_remote_bases(unsigned int cpu);
168extern void timer_unlock_remote_bases(unsigned int cpu);
169extern bool timer_base_is_idle(void);
170extern void timer_expire_remote(unsigned int cpu);
171# endif
172#else /* CONFIG_NO_HZ_COMMON */
173static inline void timers_update_nohz(void) { }
174#define tick_nohz_active (0)
175#endif
176
177DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
178
179extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
180u64 timer_base_try_to_set_idle(unsigned long basej, u64 basem, bool *idle);
181void timer_clear_idle(void);
182
183#define CLOCK_SET_WALL \
184 (BIT(HRTIMER_BASE_REALTIME) | BIT(HRTIMER_BASE_REALTIME_SOFT) | \
185 BIT(HRTIMER_BASE_TAI) | BIT(HRTIMER_BASE_TAI_SOFT))
186
187#define CLOCK_SET_BOOT \
188 (BIT(HRTIMER_BASE_BOOTTIME) | BIT(HRTIMER_BASE_BOOTTIME_SOFT))
189
190void clock_was_set(unsigned int bases);
191void clock_was_set_delayed(void);
192
193void hrtimers_resume_local(void);
194
195/* Since jiffies uses a simple TICK_NSEC multiplier
196 * conversion, the .shift value could be zero. However
197 * this would make NTP adjustments impossible as they are
198 * in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
199 * shift both the nominator and denominator the same
200 * amount, and give ntp adjustments in units of 1/2^8
201 *
202 * The value 8 is somewhat carefully chosen, as anything
203 * larger can result in overflows. TICK_NSEC grows as HZ
204 * shrinks, so values greater than 8 overflow 32bits when
205 * HZ=100.
206 */
207#if HZ < 34
208#define JIFFIES_SHIFT 6
209#elif HZ < 67
210#define JIFFIES_SHIFT 7
211#else
212#define JIFFIES_SHIFT 8
213#endif
214
215extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
216

source code of linux/kernel/time/tick-internal.h