diff options
Diffstat (limited to 'include/linux/timekeeper_internal.h')
| -rw-r--r-- | include/linux/timekeeper_internal.h | 150 |
1 files changed, 83 insertions, 67 deletions
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h index c1825eb436ed..95640dcd1899 100644 --- a/include/linux/timekeeper_internal.h +++ b/include/linux/timekeeper_internal.h @@ -10,77 +10,100 @@ #include <linux/jiffies.h> #include <linux/time.h> -/* Structure holding internal timekeeping values. */ -struct timekeeper { - /* Current clocksource used for timekeeping. */ +/** + * struct tk_read_base - base structure for timekeeping readout + * @clock: Current clocksource used for timekeeping. + * @read: Read function of @clock + * @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_mono: ktime_t (nanoseconds) base time for 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 accessor to clock monotonic. + */ +struct tk_read_base { struct clocksource *clock; - /* NTP adjusted clock multiplier */ + cycle_t (*read)(struct clocksource *cs); + cycle_t mask; + cycle_t cycle_last; u32 mult; - /* The shift value of the current clocksource. */ u32 shift; - /* Number of clock cycles in one NTP interval. */ + u64 xtime_nsec; + ktime_t base_mono; +}; + +/** + * struct timekeeper - Structure holding internal timekeeping values. + * @tkr: The readout base structure + * @xtime_sec: Current CLOCK_REALTIME 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 + * @base_raw: Monotonic raw base time in ktime_t format + * @raw_time: Monotonic raw base time in timespec64 format + * @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: 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. + * + * 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. + */ +struct timekeeper { + struct tk_read_base tkr; + u64 xtime_sec; + struct timespec64 wall_to_monotonic; + ktime_t offs_real; + ktime_t offs_boot; + ktime_t offs_tai; + s32 tai_offset; + ktime_t base_raw; + struct timespec64 raw_time; + + /* The following members are for timekeeping internal use */ cycle_t cycle_interval; - /* Last cycle value (also stored in clock->cycle_last) */ - cycle_t cycle_last; - /* Number of clock shifted nano seconds in one NTP interval. */ u64 xtime_interval; - /* shifted nano seconds left over when rounding cycle_interval */ s64 xtime_remainder; - /* Raw nano seconds accumulated per NTP interval. */ u32 raw_interval; - - /* Current CLOCK_REALTIME time in seconds */ - u64 xtime_sec; - /* Clock shifted nano seconds */ - u64 xtime_nsec; - + /* 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; - /* Shift conversion between clock shifted nano seconds and - * ntp shifted nano seconds. */ u32 ntp_error_shift; - - /* - * 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. - */ - struct timespec wall_to_monotonic; - /* Offset clock monotonic -> clock realtime */ - ktime_t offs_real; - /* time spent in suspend */ - struct timespec total_sleep_time; - /* Offset clock monotonic -> clock boottime */ - ktime_t offs_boot; - /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ - struct timespec raw_time; - /* The current UTC to TAI offset in seconds */ - s32 tai_offset; - /* Offset clock monotonic -> clock tai */ - ktime_t offs_tai; - + u32 ntp_err_mult; }; -static inline struct timespec tk_xtime(struct timekeeper *tk) -{ - struct timespec ts; - - ts.tv_sec = tk->xtime_sec; - ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift); - return ts; -} - - #ifdef CONFIG_GENERIC_TIME_VSYSCALL extern void update_vsyscall(struct timekeeper *tk); @@ -89,17 +112,10 @@ extern void update_vsyscall_tz(void); #elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD) extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm, - struct clocksource *c, u32 mult); + struct clocksource *c, u32 mult, + cycle_t cycle_last); extern void update_vsyscall_tz(void); -static inline void update_vsyscall(struct timekeeper *tk) -{ - struct timespec xt; - - xt = tk_xtime(tk); - update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); -} - #else static inline void update_vsyscall(struct timekeeper *tk) |