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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 u64 (*read)(struct clocksource *cs);
33 u64 mask;
34 u64 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 * @clock_was_set_seq: The sequence number of clock was set events
53 * @cs_was_changed_seq: The sequence number of clocksource change events
54 * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second
55 * @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.
66 * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING)
67 * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING)
68 * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING)
69 *
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.
76 *
77 * wall_to_monotonic is moved after resume from suspend for the
78 * 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.
80 *
81 * wall_to_monotonic is no longer the boot time, getboottime must be
82 * used instead.
83 */
84struct timekeeper {
85 struct tk_read_base tkr_mono;
86 struct tk_read_base tkr_raw;
87 u64 xtime_sec;
88 unsigned long ktime_sec;
89 struct timespec64 wall_to_monotonic;
90 ktime_t offs_real;
91 ktime_t offs_boot;
92 ktime_t offs_tai;
93 s32 tai_offset;
94 unsigned int clock_was_set_seq;
95 u8 cs_was_changed_seq;
96 ktime_t next_leap_ktime;
97 struct timespec64 raw_time;
98
99 /* The following members are for timekeeping internal use */
100 u64 cycle_interval;
101 u64 xtime_interval;
102 s64 xtime_remainder;
103 u32 raw_interval;
104 /* 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. */
113 s64 ntp_error;
114 u32 ntp_error_shift;
115 u32 ntp_err_mult;
116#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
128};
129
130#ifdef CONFIG_GENERIC_TIME_VSYSCALL
131
132extern void update_vsyscall(struct timekeeper *tk);
133extern void update_vsyscall_tz(void);
134
135#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
136
137extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
138 struct clocksource *c, u32 mult,
139 u64 cycle_last);
140extern void update_vsyscall_tz(void);
141
142#else
143
144static inline void update_vsyscall(struct timekeeper *tk)
145{
146}
147static inline void update_vsyscall_tz(void)
148{
149}
150#endif
151
152#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * You SHOULD NOT be including this unless you're vsyscall
4 * handling code or timekeeping internal code!
5 */
6
7#ifndef _LINUX_TIMEKEEPER_INTERNAL_H
8#define _LINUX_TIMEKEEPER_INTERNAL_H
9
10#include <linux/clocksource.h>
11#include <linux/jiffies.h>
12#include <linux/time.h>
13
14/**
15 * struct tk_read_base - base structure for timekeeping readout
16 * @clock: Current clocksource used for timekeeping.
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 * @base_real: Nanoseconds base value for clock REALTIME readout
24 *
25 * This struct has size 56 byte on 64 bit. Together with a seqcount it
26 * occupies a single 64byte cache line.
27 *
28 * The struct is separate from struct timekeeper as it is also used
29 * for a fast NMI safe accessors.
30 *
31 * @base_real is for the fast NMI safe accessor to allow reading clock
32 * realtime from any context.
33 */
34struct tk_read_base {
35 struct clocksource *clock;
36 u64 mask;
37 u64 cycle_last;
38 u32 mult;
39 u32 shift;
40 u64 xtime_nsec;
41 ktime_t base;
42 u64 base_real;
43};
44
45/**
46 * struct timekeeper - Structure holding internal timekeeping values.
47 * @tkr_mono: The readout base structure for CLOCK_MONOTONIC
48 * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW
49 * @xtime_sec: Current CLOCK_REALTIME time in seconds
50 * @ktime_sec: Current CLOCK_MONOTONIC time in seconds
51 * @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset
52 * @offs_real: Offset clock monotonic -> clock realtime
53 * @offs_boot: Offset clock monotonic -> clock boottime
54 * @offs_tai: Offset clock monotonic -> clock tai
55 * @tai_offset: The current UTC to TAI offset in seconds
56 * @clock_was_set_seq: The sequence number of clock was set events
57 * @cs_was_changed_seq: The sequence number of clocksource change events
58 * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second
59 * @raw_sec: CLOCK_MONOTONIC_RAW time in seconds
60 * @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset
61 * @cycle_interval: Number of clock cycles in one NTP interval
62 * @xtime_interval: Number of clock shifted nano seconds in one NTP
63 * interval.
64 * @xtime_remainder: Shifted nano seconds left over when rounding
65 * @cycle_interval
66 * @raw_interval: Shifted raw nano seconds accumulated per NTP interval.
67 * @ntp_error: Difference between accumulated time and NTP time in ntp
68 * shifted nano seconds.
69 * @ntp_error_shift: Shift conversion between clock shifted nano seconds and
70 * ntp shifted nano seconds.
71 * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING)
72 * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING)
73 * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING)
74 *
75 * Note: For timespec(64) based interfaces wall_to_monotonic is what
76 * we need to add to xtime (or xtime corrected for sub jiffie times)
77 * to get to monotonic time. Monotonic is pegged at zero at system
78 * boot time, so wall_to_monotonic will be negative, however, we will
79 * ALWAYS keep the tv_nsec part positive so we can use the usual
80 * normalization.
81 *
82 * wall_to_monotonic is moved after resume from suspend for the
83 * monotonic time not to jump. We need to add total_sleep_time to
84 * wall_to_monotonic to get the real boot based time offset.
85 *
86 * wall_to_monotonic is no longer the boot time, getboottime must be
87 * used instead.
88 *
89 * @monotonic_to_boottime is a timespec64 representation of @offs_boot to
90 * accelerate the VDSO update for CLOCK_BOOTTIME.
91 */
92struct timekeeper {
93 struct tk_read_base tkr_mono;
94 struct tk_read_base tkr_raw;
95 u64 xtime_sec;
96 unsigned long ktime_sec;
97 struct timespec64 wall_to_monotonic;
98 ktime_t offs_real;
99 ktime_t offs_boot;
100 ktime_t offs_tai;
101 s32 tai_offset;
102 unsigned int clock_was_set_seq;
103 u8 cs_was_changed_seq;
104 ktime_t next_leap_ktime;
105 u64 raw_sec;
106 struct timespec64 monotonic_to_boot;
107
108 /* The following members are for timekeeping internal use */
109 u64 cycle_interval;
110 u64 xtime_interval;
111 s64 xtime_remainder;
112 u64 raw_interval;
113 /* The ntp_tick_length() value currently being used.
114 * This cached copy ensures we consistently apply the tick
115 * length for an entire tick, as ntp_tick_length may change
116 * mid-tick, and we don't want to apply that new value to
117 * the tick in progress.
118 */
119 u64 ntp_tick;
120 /* Difference between accumulated time and NTP time in ntp
121 * shifted nano seconds. */
122 s64 ntp_error;
123 u32 ntp_error_shift;
124 u32 ntp_err_mult;
125 /* Flag used to avoid updating NTP twice with same second */
126 u32 skip_second_overflow;
127#ifdef CONFIG_DEBUG_TIMEKEEPING
128 long last_warning;
129 /*
130 * These simple flag variables are managed
131 * without locks, which is racy, but they are
132 * ok since we don't really care about being
133 * super precise about how many events were
134 * seen, just that a problem was observed.
135 */
136 int underflow_seen;
137 int overflow_seen;
138#endif
139};
140
141#ifdef CONFIG_GENERIC_TIME_VSYSCALL
142
143extern void update_vsyscall(struct timekeeper *tk);
144extern void update_vsyscall_tz(void);
145
146#else
147
148static inline void update_vsyscall(struct timekeeper *tk)
149{
150}
151static inline void update_vsyscall_tz(void)
152{
153}
154#endif
155
156#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */