130 lines
4.2 KiB
C
130 lines
4.2 KiB
C
/*
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* You SHOULD NOT be including this unless you're vsyscall
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* handling code or timekeeping internal code!
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*/
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#ifndef _LINUX_TIMEKEEPER_INTERNAL_H
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#define _LINUX_TIMEKEEPER_INTERNAL_H
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#include <linux/clocksource.h>
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#include <linux/jiffies.h>
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#include <linux/time.h>
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/**
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* struct tk_read_base - base structure for timekeeping readout
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* @clock: Current clocksource used for timekeeping.
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* @read: Read function of @clock
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* @mask: Bitmask for two's complement subtraction of non 64bit clocks
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* @cycle_last: @clock cycle value at last update
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* @mult: NTP adjusted multiplier for scaled math conversion
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* @shift: Shift value for scaled math conversion
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* @xtime_nsec: Shifted (fractional) nano seconds offset for readout
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* @base_mono: ktime_t (nanoseconds) base time for readout
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*
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* This struct has size 56 byte on 64 bit. Together with a seqcount it
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* occupies a single 64byte cache line.
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*
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* The struct is separate from struct timekeeper as it is also used
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* for a fast NMI safe accessor to clock monotonic.
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*/
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struct tk_read_base {
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struct clocksource *clock;
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cycle_t (*read)(struct clocksource *cs);
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cycle_t mask;
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cycle_t cycle_last;
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u32 mult;
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u32 shift;
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u64 xtime_nsec;
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ktime_t base_mono;
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};
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/**
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* struct timekeeper - Structure holding internal timekeeping values.
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* @tkr: The readout base structure
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* @xtime_sec: Current CLOCK_REALTIME time in seconds
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* @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset
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* @offs_real: Offset clock monotonic -> clock realtime
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* @offs_boot: Offset clock monotonic -> clock boottime
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* @offs_tai: Offset clock monotonic -> clock tai
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* @tai_offset: The current UTC to TAI offset in seconds
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* @base_raw: Monotonic raw base time in ktime_t format
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* @raw_time: Monotonic raw base time in timespec64 format
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* @cycle_interval: Number of clock cycles in one NTP interval
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* @xtime_interval: Number of clock shifted nano seconds in one NTP
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* interval.
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* @xtime_remainder: Shifted nano seconds left over when rounding
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* @cycle_interval
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* @raw_interval: Raw nano seconds accumulated per NTP interval.
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* @ntp_error: Difference between accumulated time and NTP time in ntp
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* shifted nano seconds.
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* @ntp_error_shift: Shift conversion between clock shifted nano seconds and
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* ntp shifted nano seconds.
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*
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* Note: For timespec(64) based interfaces wall_to_monotonic is what
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* we need to add to xtime (or xtime corrected for sub jiffie times)
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* to get to monotonic time. Monotonic is pegged at zero at system
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* boot time, so wall_to_monotonic will be negative, however, we will
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* ALWAYS keep the tv_nsec part positive so we can use the usual
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* normalization.
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*
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* wall_to_monotonic is moved after resume from suspend for the
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* monotonic time not to jump. We need to add total_sleep_time to
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* wall_to_monotonic to get the real boot based time offset.
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*
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* wall_to_monotonic is no longer the boot time, getboottime must be
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* used instead.
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*/
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struct timekeeper {
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struct tk_read_base tkr;
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u64 xtime_sec;
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struct timespec64 wall_to_monotonic;
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ktime_t offs_real;
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ktime_t offs_boot;
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ktime_t offs_tai;
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s32 tai_offset;
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ktime_t base_raw;
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struct timespec64 raw_time;
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/* The following members are for timekeeping internal use */
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cycle_t cycle_interval;
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u64 xtime_interval;
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s64 xtime_remainder;
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u32 raw_interval;
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/* The ntp_tick_length() value currently being used.
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* This cached copy ensures we consistently apply the tick
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* length for an entire tick, as ntp_tick_length may change
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* mid-tick, and we don't want to apply that new value to
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* the tick in progress.
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*/
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u64 ntp_tick;
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/* Difference between accumulated time and NTP time in ntp
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* shifted nano seconds. */
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s64 ntp_error;
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u32 ntp_error_shift;
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u32 ntp_err_mult;
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};
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#ifdef CONFIG_GENERIC_TIME_VSYSCALL
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extern void update_vsyscall(struct timekeeper *tk);
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extern void update_vsyscall_tz(void);
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#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
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extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
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struct clocksource *c, u32 mult,
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cycle_t cycle_last);
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extern void update_vsyscall_tz(void);
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#else
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static inline void update_vsyscall(struct timekeeper *tk)
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{
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}
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static inline void update_vsyscall_tz(void)
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{
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}
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#endif
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#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
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