1/*
2 * You SHOULD NOT be including this unless you're vsyscall
3 * handling code or timekeeping internal code!
4 */
5
6#ifndef _LINUX_TIMEKEEPER_INTERNAL_H
7#define _LINUX_TIMEKEEPER_INTERNAL_H
8
9#include <linux/clocksource.h>
10#include <linux/jiffies.h>
11#include <linux/time.h>
12
13/**
14 * struct tk_read_base - base structure for timekeeping readout
15 * @clock:	Current clocksource used for timekeeping.
16 * @read:	Read function of @clock
17 * @mask:	Bitmask for two's complement subtraction of non 64bit clocks
18 * @cycle_last: @clock cycle value at last update
19 * @mult:	(NTP adjusted) multiplier for scaled math conversion
20 * @shift:	Shift value for scaled math conversion
21 * @xtime_nsec: Shifted (fractional) nano seconds offset for readout
22 * @base:	ktime_t (nanoseconds) base time for readout
23 *
24 * This struct has size 56 byte on 64 bit. Together with a seqcount it
25 * occupies a single 64byte cache line.
26 *
27 * The struct is separate from struct timekeeper as it is also used
28 * for a fast NMI safe accessors.
29 */
30struct tk_read_base {
31	struct clocksource	*clock;
32	cycle_t			(*read)(struct clocksource *cs);
33	cycle_t			mask;
34	cycle_t			cycle_last;
35	u32			mult;
36	u32			shift;
37	u64			xtime_nsec;
38	ktime_t			base;
39};
40
41/**
42 * struct timekeeper - Structure holding internal timekeeping values.
43 * @tkr_mono:		The readout base structure for CLOCK_MONOTONIC
44 * @tkr_raw:		The readout base structure for CLOCK_MONOTONIC_RAW
45 * @xtime_sec:		Current CLOCK_REALTIME time in seconds
46 * @ktime_sec:		Current CLOCK_MONOTONIC time in seconds
47 * @wall_to_monotonic:	CLOCK_REALTIME to CLOCK_MONOTONIC offset
48 * @offs_real:		Offset clock monotonic -> clock realtime
49 * @offs_boot:		Offset clock monotonic -> clock boottime
50 * @offs_tai:		Offset clock monotonic -> clock tai
51 * @tai_offset:		The current UTC to TAI offset in seconds
52 * @raw_time:		Monotonic raw base time in timespec64 format
53 * @cycle_interval:	Number of clock cycles in one NTP interval
54 * @xtime_interval:	Number of clock shifted nano seconds in one NTP
55 *			interval.
56 * @xtime_remainder:	Shifted nano seconds left over when rounding
57 *			@cycle_interval
58 * @raw_interval:	Raw nano seconds accumulated per NTP interval.
59 * @ntp_error:		Difference between accumulated time and NTP time in ntp
60 *			shifted nano seconds.
61 * @ntp_error_shift:	Shift conversion between clock shifted nano seconds and
62 *			ntp shifted nano seconds.
63 *
64 * Note: For timespec(64) based interfaces wall_to_monotonic is what
65 * we need to add to xtime (or xtime corrected for sub jiffie times)
66 * to get to monotonic time.  Monotonic is pegged at zero at system
67 * boot time, so wall_to_monotonic will be negative, however, we will
68 * ALWAYS keep the tv_nsec part positive so we can use the usual
69 * normalization.
70 *
71 * wall_to_monotonic is moved after resume from suspend for the
72 * monotonic time not to jump. We need to add total_sleep_time to
73 * wall_to_monotonic to get the real boot based time offset.
74 *
75 * wall_to_monotonic is no longer the boot time, getboottime must be
76 * used instead.
77 */
78struct timekeeper {
79	struct tk_read_base	tkr_mono;
80	struct tk_read_base	tkr_raw;
81	u64			xtime_sec;
82	unsigned long		ktime_sec;
83	struct timespec64	wall_to_monotonic;
84	ktime_t			offs_real;
85	ktime_t			offs_boot;
86	ktime_t			offs_tai;
87	s32			tai_offset;
88	struct timespec64	raw_time;
89
90	/* The following members are for timekeeping internal use */
91	cycle_t			cycle_interval;
92	u64			xtime_interval;
93	s64			xtime_remainder;
94	u32			raw_interval;
95	/* The ntp_tick_length() value currently being used.
96	 * This cached copy ensures we consistently apply the tick
97	 * length for an entire tick, as ntp_tick_length may change
98	 * mid-tick, and we don't want to apply that new value to
99	 * the tick in progress.
100	 */
101	u64			ntp_tick;
102	/* Difference between accumulated time and NTP time in ntp
103	 * shifted nano seconds. */
104	s64			ntp_error;
105	u32			ntp_error_shift;
106	u32			ntp_err_mult;
107};
108
109#ifdef CONFIG_GENERIC_TIME_VSYSCALL
110
111extern void update_vsyscall(struct timekeeper *tk);
112extern void update_vsyscall_tz(void);
113
114#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
115
116extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
117				struct clocksource *c, u32 mult,
118				cycle_t cycle_last);
119extern void update_vsyscall_tz(void);
120
121#else
122
123static inline void update_vsyscall(struct timekeeper *tk)
124{
125}
126static inline void update_vsyscall_tz(void)
127{
128}
129#endif
130
131#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
132