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156 lines
5.3 KiB
156 lines
5.3 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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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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* @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: ktime_t (nanoseconds) base time for readout |
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* @base_real: Nanoseconds base value for clock REALTIME 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 accessors. |
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* |
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* @base_real is for the fast NMI safe accessor to allow reading clock |
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* realtime from any context. |
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*/ |
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struct tk_read_base { |
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struct clocksource *clock; |
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u64 mask; |
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u64 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; |
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u64 base_real; |
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}; |
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/** |
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* struct timekeeper - Structure holding internal timekeeping values. |
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* @tkr_mono: The readout base structure for CLOCK_MONOTONIC |
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* @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW |
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* @xtime_sec: Current CLOCK_REALTIME time in seconds |
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* @ktime_sec: Current CLOCK_MONOTONIC 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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* @clock_was_set_seq: The sequence number of clock was set events |
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* @cs_was_changed_seq: The sequence number of clocksource change events |
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* @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second |
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* @raw_sec: CLOCK_MONOTONIC_RAW time in seconds |
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* @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset |
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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: Shifted 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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* @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING) |
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* @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING) |
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* @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING) |
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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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* @monotonic_to_boottime is a timespec64 representation of @offs_boot to |
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* accelerate the VDSO update for CLOCK_BOOTTIME. |
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*/ |
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struct timekeeper { |
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struct tk_read_base tkr_mono; |
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struct tk_read_base tkr_raw; |
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u64 xtime_sec; |
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unsigned long ktime_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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unsigned int clock_was_set_seq; |
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u8 cs_was_changed_seq; |
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ktime_t next_leap_ktime; |
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u64 raw_sec; |
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struct timespec64 monotonic_to_boot; |
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/* The following members are for timekeeping internal use */ |
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u64 cycle_interval; |
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u64 xtime_interval; |
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s64 xtime_remainder; |
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u64 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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/* Flag used to avoid updating NTP twice with same second */ |
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u32 skip_second_overflow; |
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#ifdef CONFIG_DEBUG_TIMEKEEPING |
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long last_warning; |
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/* |
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* These simple flag variables are managed |
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* without locks, which is racy, but they are |
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* ok since we don't really care about being |
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* super precise about how many events were |
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* seen, just that a problem was observed. |
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*/ |
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int underflow_seen; |
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int overflow_seen; |
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#endif |
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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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#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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