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John Stultzd7b42022012-09-04 15:12:07 -04001/*
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
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000013/**
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
Peter Zijlstra876e7882015-03-19 10:09:06 +010019 * @mult: (NTP adjusted) multiplier for scaled math conversion
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000020 * @shift: Shift value for scaled math conversion
21 * @xtime_nsec: Shifted (fractional) nano seconds offset for readout
Peter Zijlstra876e7882015-03-19 10:09:06 +010022 * @base: ktime_t (nanoseconds) base time for readout
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000023 *
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000024 * 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
Peter Zijlstra876e7882015-03-19 10:09:06 +010028 * for a fast NMI safe accessors.
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000029 */
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;
Peter Zijlstra876e7882015-03-19 10:09:06 +010038 ktime_t base;
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000039};
40
41/**
42 * struct timekeeper - Structure holding internal timekeeping values.
Peter Zijlstra876e7882015-03-19 10:09:06 +010043 * @tkr_mono: The readout base structure for CLOCK_MONOTONIC
Peter Zijlstra4a4ad802015-03-19 09:28:44 +010044 * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000045 * @xtime_sec: Current CLOCK_REALTIME time in seconds
Heena Sirwani9e3680b2014-10-29 16:01:16 +053046 * @ktime_sec: Current CLOCK_MONOTONIC time in seconds
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000047 * @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
Thomas Gleixner868a3e92015-04-14 21:08:37 +000052 * @clock_was_set_seq: The sequence number of clock was set events
Christopher S. Hall2c756fe2016-02-22 03:15:23 -080053 * @cs_was_changed_seq: The sequence number of clocksource change events
John Stultz833f32d2015-06-11 15:54:55 -070054 * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000055 * @raw_time: Monotonic raw base time in timespec64 format
56 * @cycle_interval: Number of clock cycles in one NTP interval
57 * @xtime_interval: Number of clock shifted nano seconds in one NTP
58 * interval.
59 * @xtime_remainder: Shifted nano seconds left over when rounding
60 * @cycle_interval
61 * @raw_interval: Raw nano seconds accumulated per NTP interval.
62 * @ntp_error: Difference between accumulated time and NTP time in ntp
63 * shifted nano seconds.
64 * @ntp_error_shift: Shift conversion between clock shifted nano seconds and
65 * ntp shifted nano seconds.
John Stultz57d05a92015-05-13 16:04:47 -070066 * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING)
67 * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING)
68 * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING)
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000069 *
70 * Note: For timespec(64) based interfaces wall_to_monotonic is what
71 * we need to add to xtime (or xtime corrected for sub jiffie times)
72 * to get to monotonic time. Monotonic is pegged at zero at system
73 * boot time, so wall_to_monotonic will be negative, however, we will
74 * ALWAYS keep the tv_nsec part positive so we can use the usual
75 * normalization.
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000076 *
77 * wall_to_monotonic is moved after resume from suspend for the
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000078 * monotonic time not to jump. We need to add total_sleep_time to
79 * wall_to_monotonic to get the real boot based time offset.
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000080 *
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000081 * wall_to_monotonic is no longer the boot time, getboottime must be
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000082 * used instead.
83 */
John Stultzd7b42022012-09-04 15:12:07 -040084struct timekeeper {
Peter Zijlstra876e7882015-03-19 10:09:06 +010085 struct tk_read_base tkr_mono;
Peter Zijlstra4a4ad802015-03-19 09:28:44 +010086 struct tk_read_base tkr_raw;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000087 u64 xtime_sec;
Heena Sirwani9e3680b2014-10-29 16:01:16 +053088 unsigned long ktime_sec;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000089 struct timespec64 wall_to_monotonic;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000090 ktime_t offs_real;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000091 ktime_t offs_boot;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000092 ktime_t offs_tai;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000093 s32 tai_offset;
Thomas Gleixner868a3e92015-04-14 21:08:37 +000094 unsigned int clock_was_set_seq;
Christopher S. Hall2c756fe2016-02-22 03:15:23 -080095 u8 cs_was_changed_seq;
John Stultz833f32d2015-06-11 15:54:55 -070096 ktime_t next_leap_ktime;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +000097 struct timespec64 raw_time;
98
Thomas Gleixnerd28ede82014-07-16 21:05:16 +000099 /* The following members are for timekeeping internal use */
John Stultzd7b42022012-09-04 15:12:07 -0400100 cycle_t cycle_interval;
John Stultzd7b42022012-09-04 15:12:07 -0400101 u64 xtime_interval;
John Stultzd7b42022012-09-04 15:12:07 -0400102 s64 xtime_remainder;
John Stultzd7b42022012-09-04 15:12:07 -0400103 u32 raw_interval;
John Stultz375f45b2014-04-23 20:53:29 -0700104 /* The ntp_tick_length() value currently being used.
105 * This cached copy ensures we consistently apply the tick
106 * length for an entire tick, as ntp_tick_length may change
107 * mid-tick, and we don't want to apply that new value to
108 * the tick in progress.
109 */
110 u64 ntp_tick;
111 /* Difference between accumulated time and NTP time in ntp
112 * shifted nano seconds. */
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +0000113 s64 ntp_error;
Thomas Gleixner3fdb14f2014-07-16 21:04:07 +0000114 u32 ntp_error_shift;
John Stultzdc491592013-12-06 17:25:21 -0800115 u32 ntp_err_mult;
John Stultz57d05a92015-05-13 16:04:47 -0700116#ifdef CONFIG_DEBUG_TIMEKEEPING
117 long last_warning;
118 /*
119 * These simple flag variables are managed
120 * without locks, which is racy, but they are
121 * ok since we don't really care about being
122 * super precise about how many events were
123 * seen, just that a problem was observed.
124 */
125 int underflow_seen;
126 int overflow_seen;
127#endif
John Stultzd7b42022012-09-04 15:12:07 -0400128};
John Stultz189374a2012-09-04 15:27:48 -0400129
John Stultz576094b2012-09-11 19:58:13 -0400130#ifdef CONFIG_GENERIC_TIME_VSYSCALL
131
132extern void update_vsyscall(struct timekeeper *tk);
John Stultz189374a2012-09-04 15:27:48 -0400133extern void update_vsyscall_tz(void);
John Stultz576094b2012-09-11 19:58:13 -0400134
135#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
136
137extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
Thomas Gleixner4a0e6372014-07-16 21:05:13 +0000138 struct clocksource *c, u32 mult,
John Stultz953dec22014-07-25 21:37:19 -0700139 cycle_t cycle_last);
John Stultz576094b2012-09-11 19:58:13 -0400140extern void update_vsyscall_tz(void);
141
John Stultz189374a2012-09-04 15:27:48 -0400142#else
John Stultz576094b2012-09-11 19:58:13 -0400143
144static inline void update_vsyscall(struct timekeeper *tk)
John Stultz189374a2012-09-04 15:27:48 -0400145{
146}
147static inline void update_vsyscall_tz(void)
148{
149}
150#endif
151
John Stultzd7b42022012-09-04 15:12:07 -0400152#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */