#include <linux/jiffies.h>
#include <linux/time.h>
-/*
- * Structure holding internal timekeeping values.
- *
- * Note: 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.
+/**
+ * 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
*
- * wall_to_monotonic is moved after resume from suspend for the
- * monotonic time not to jump. To calculate the real boot time offset
- * we need to do offs_real - offs_boot.
+ * This struct has size 56 byte on 64 bit. Together with a seqcount it
+ * occupies a single 64byte cache line.
*
- * - wall_to_monotonic is no longer the boot time, getboottime must be
- * used instead.
+ * The struct is separate from struct timekeeper as it is also used
+ * for a fast NMI safe accessor to clock monotonic.
*/
-struct timekeeper {
- /* Current clocksource used for timekeeping. */
+struct tk_read_base {
struct clocksource *clock;
- /* Last cycle value */
+ cycle_t (*read)(struct clocksource *cs);
+ cycle_t mask;
cycle_t cycle_last;
- /* NTP adjusted clock multiplier */
u32 mult;
- /* The shift value of the current clocksource. */
u32 shift;
- /* Clock shifted nano seconds */
u64 xtime_nsec;
-
- /* Monotonic base time */
ktime_t base_mono;
+};
- /* Current CLOCK_REALTIME time in seconds */
+/**
+ * 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;
- /* CLOCK_REALTIME to CLOCK_MONOTONIC offset */
struct timespec64 wall_to_monotonic;
-
- /* Offset clock monotonic -> clock realtime */
ktime_t offs_real;
- /* Offset clock monotonic -> clock boottime */
ktime_t offs_boot;
- /* Offset clock monotonic -> clock tai */
ktime_t offs_tai;
-
- /* The current UTC to TAI offset in seconds */
s32 tai_offset;
-
- /* Monotonic raw base time */
ktime_t base_raw;
-
- /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
struct timespec64 raw_time;
- /* Number of clock cycles in one NTP interval. */
+ /* The following members are for timekeeping internal use */
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;
-
- /*
- * Difference between accumulated time and NTP time in ntp
- * shifted nano seconds.
+ /* 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;
+ u32 ntp_err_mult;
};
#ifdef CONFIG_GENERIC_TIME_VSYSCALL
extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
struct clocksource *c, u32 mult,
- cycles_t cycle_last);
+ cycle_t cycle_last);
extern void update_vsyscall_tz(void);
#else
projects / mirror_ubuntu-zesty-kernel.git / blobdiff