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 * @read: Read function of @clock 18 * @mask: Bitmask for two's complement subtraction of non 64bit clocks 19 * @cycle_last: @clock cycle value at last update 20 * @mult: (NTP adjusted) multiplier for scaled math conversion 21 * @shift: Shift value for scaled math conversion 22 * @xtime_nsec: Shifted (fractional) nano seconds offset for readout 23 * @base: ktime_t (nanoseconds) base time for 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 struct tk_read_base { 32 struct clocksource *clock; 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_sec: CLOCK_MONOTONIC_RAW time in seconds 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: Shifted 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 */ 84 struct 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 u64 raw_sec; 98 99 /* The following members are for timekeeping internal use */ 100 u64 cycle_interval; 101 u64 xtime_interval; 102 s64 xtime_remainder; 103 u64 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 131 132 extern void update_vsyscall(struct timekeeper *tk); 133 extern void update_vsyscall_tz(void); 134 135 #elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD) 136 137 extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm, 138 struct clocksource *c, u32 mult, 139 u64 cycle_last); 140 extern void update_vsyscall_tz(void); 141 142 #else 143 144 static inline void update_vsyscall(struct timekeeper *tk) 145 { 146 } 147 static inline void update_vsyscall_tz(void) 148 { 149 } 150 #endif 151 152 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */ 153