name : timekeeper_internal.h /* SPDX-License-Identifier: GPL-2.0 */ /* * You SHOULD NOT be including this unless you're vsyscall * handling code or timekeeping internal code! */ #ifndef _LINUX_TIMEKEEPER_INTERNAL_H #define _LINUX_TIMEKEEPER_INTERNAL_H #include <linux/clocksource.h> #include <linux/jiffies.h> #include <linux/time.h> /** * struct tk_read_base - base structure for timekeeping readout * @clock: Current clocksource used for timekeeping. * @mask: Bitmask for two's complement subtraction of non 64bit clocks * @cycle_last: @clock cycle value at last update * @mult: (NTP adjusted) multiplier for scaled math conversion * @shift: Shift value for scaled math conversion * @xtime_nsec: Shifted (fractional) nano seconds offset for readout * @base: ktime_t (nanoseconds) base time for readout * @base_real: Nanoseconds base value for clock REALTIME readout * * This struct has size 56 byte on 64 bit. Together with a seqcount it * occupies a single 64byte cache line. * * The struct is separate from struct timekeeper as it is also used * for a fast NMI safe accessors. * * @base_real is for the fast NMI safe accessor to allow reading clock * realtime from any context. */ struct tk_read_base { struct clocksource *clock; u64 mask; u64 cycle_last; u32 mult; u32 shift; u64 xtime_nsec; ktime_t base; u64 base_real; }; /** * struct timekeeper - Structure holding internal timekeeping values. * @tkr_mono: The readout base structure for CLOCK_MONOTONIC * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW * @xtime_sec: Current CLOCK_REALTIME time in seconds * @ktime_sec: Current CLOCK_MONOTONIC time in seconds * @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset * @offs_real: Offset clock monotonic -> clock realtime * @offs_boot: Offset clock monotonic -> clock boottime * @offs_tai: Offset clock monotonic -> clock tai * @tai_offset: The current UTC to TAI offset in seconds * @clock_was_set_seq: The sequence number of clock was set events * @cs_was_changed_seq: The sequence number of clocksource change events * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second * @raw_sec: CLOCK_MONOTONIC_RAW time in seconds * @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset * @cycle_interval: Number of clock cycles in one NTP interval * @xtime_interval: Number of clock shifted nano seconds in one NTP * interval. * @xtime_remainder: Shifted nano seconds left over when rounding * @cycle_interval * @raw_interval: Shifted raw nano seconds accumulated per NTP interval. * @ntp_error: Difference between accumulated time and NTP time in ntp * shifted nano seconds. * @ntp_error_shift: Shift conversion between clock shifted nano seconds and * ntp shifted nano seconds. * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING) * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING) * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING) * * Note: For timespec(64) based interfaces wall_to_monotonic is what * we need to add to xtime (or xtime corrected for sub jiffie times) * to get to monotonic time. Monotonic is pegged at zero at system * boot time, so wall_to_monotonic will be negative, however, we will * ALWAYS keep the tv_nsec part positive so we can use the usual * normalization. * * wall_to_monotonic is moved after resume from suspend for the * monotonic time not to jump. We need to add total_sleep_time to * wall_to_monotonic to get the real boot based time offset. * * wall_to_monotonic is no longer the boot time, getboottime must be * used instead. * * @monotonic_to_boottime is a timespec64 representation of @offs_boot to * accelerate the VDSO update for CLOCK_BOOTTIME. */ struct timekeeper { struct tk_read_base tkr_mono; struct tk_read_base tkr_raw; u64 xtime_sec; unsigned long ktime_sec; struct timespec64 wall_to_monotonic; ktime_t offs_real; ktime_t offs_boot; ktime_t offs_tai; s32 tai_offset; unsigned int clock_was_set_seq; u8 cs_was_changed_seq; ktime_t next_leap_ktime; u64 raw_sec; struct timespec64 monotonic_to_boot; /* The following members are for timekeeping internal use */ u64 cycle_interval; u64 xtime_interval; s64 xtime_remainder; u64 raw_interval; /* The ntp_tick_length() value currently being used. * This cached copy ensures we consistently apply the tick * length for an entire tick, as ntp_tick_length may change * mid-tick, and we don't want to apply that new value to * the tick in progress. */ u64 ntp_tick; /* Difference between accumulated time and NTP time in ntp * shifted nano seconds. */ s64 ntp_error; u32 ntp_error_shift; u32 ntp_err_mult; /* Flag used to avoid updating NTP twice with same second */ u32 skip_second_overflow; #ifdef CONFIG_DEBUG_TIMEKEEPING long last_warning; /* * These simple flag variables are managed * without locks, which is racy, but they are * ok since we don't really care about being * super precise about how many events were * seen, just that a problem was observed. */ int underflow_seen; int overflow_seen; #endif }; #ifdef CONFIG_GENERIC_TIME_VSYSCALL extern void update_vsyscall(struct timekeeper *tk); extern void update_vsyscall_tz(void); #else static inline void update_vsyscall(struct timekeeper *tk) { } static inline void update_vsyscall_tz(void) { } #endif #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */