timekeeper_internal.h

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/*
 * 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>

/* Structure holding internal timekeeping values. */
struct timekeeper {
    /* Current clocksource used for timekeeping. */
    struct clocksource  *clock;
    /* NTP adjusted clock multiplier */
    u32         mult;
    /* The shift value of the current clocksource. */
    u32         shift;
    /* Number of clock cycles in one NTP interval. */
    cycle_t         cycle_interval;
    /* 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;

    /* 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;
    /* Seqlock for all timekeeper values */
    seqlock_t       lock;
};

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);
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);
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)
{
}
static inline void update_vsyscall_tz(void)
{
}
#endif

#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */