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 * @cycle_interval: Number of clock cycles in one NTP interval 61 * @xtime_interval: Number of clock shifted nano seconds in one NTP 62 * interval. 63 * @xtime_remainder: Shifted nano seconds left over when rounding 64 * @cycle_interval 65 * @raw_interval: Shifted raw nano seconds accumulated per NTP interval. 66 * @ntp_error: Difference between accumulated time and NTP time in ntp 67 * shifted nano seconds. 68 * @ntp_error_shift: Shift conversion between clock shifted nano seconds and 69 * ntp shifted nano seconds. 70 * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING) 71 * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING) 72 * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING) 73 * 74 * Note: For timespec(64) based interfaces wall_to_monotonic is what 75 * we need to add to xtime (or xtime corrected for sub jiffie times) 76 * to get to monotonic time. Monotonic is pegged at zero at system 77 * boot time, so wall_to_monotonic will be negative, however, we will 78 * ALWAYS keep the tv_nsec part positive so we can use the usual 79 * normalization. 80 * 81 * wall_to_monotonic is moved after resume from suspend for the 82 * monotonic time not to jump. We need to add total_sleep_time to 83 * wall_to_monotonic to get the real boot based time offset. 84 * 85 * wall_to_monotonic is no longer the boot time, getboottime must be 86 * used instead. 87 */ 88struct timekeeper { 89 struct tk_read_base tkr_mono; 90 struct tk_read_base tkr_raw; 91 u64 xtime_sec; 92 unsigned long ktime_sec; 93 struct timespec64 wall_to_monotonic; 94 ktime_t offs_real; 95 ktime_t offs_boot; 96 ktime_t offs_tai; 97 s32 tai_offset; 98 unsigned int clock_was_set_seq; 99 u8 cs_was_changed_seq; 100 ktime_t next_leap_ktime; 101 u64 raw_sec; 102 103 /* The following members are for timekeeping internal use */ 104 u64 cycle_interval; 105 u64 xtime_interval; 106 s64 xtime_remainder; 107 u64 raw_interval; 108 /* The ntp_tick_length() value currently being used. 109 * This cached copy ensures we consistently apply the tick 110 * length for an entire tick, as ntp_tick_length may change 111 * mid-tick, and we don't want to apply that new value to 112 * the tick in progress. 113 */ 114 u64 ntp_tick; 115 /* Difference between accumulated time and NTP time in ntp 116 * shifted nano seconds. */ 117 s64 ntp_error; 118 u32 ntp_error_shift; 119 u32 ntp_err_mult; 120 /* Flag used to avoid updating NTP twice with same second */ 121 u32 skip_second_overflow; 122#ifdef CONFIG_DEBUG_TIMEKEEPING 123 long last_warning; 124 /* 125 * These simple flag variables are managed 126 * without locks, which is racy, but they are 127 * ok since we don't really care about being 128 * super precise about how many events were 129 * seen, just that a problem was observed. 130 */ 131 int underflow_seen; 132 int overflow_seen; 133#endif 134}; 135 136#ifdef CONFIG_GENERIC_TIME_VSYSCALL 137 138extern void update_vsyscall(struct timekeeper *tk); 139extern void update_vsyscall_tz(void); 140 141#else 142 143static inline void update_vsyscall(struct timekeeper *tk) 144{ 145} 146static inline void update_vsyscall_tz(void) 147{ 148} 149#endif 150 151#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */ 152