[linux-2.6-block.git] / include / linux / timekeeper_internal.h

/*
 * 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>

/**
 * 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:	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 accessors.
 */
struct tk_read_base {
	struct clocksource	*clock;
	cycle_t			(*read)(struct clocksource *cs);
	cycle_t			mask;
	cycle_t			cycle_last;
	u32			mult;
	u32			shift;
	u64			xtime_nsec;
	ktime_t			base;
};

/**
 * struct timekeeper - Structure holding internal timekeeping values.
 * @tkr_mono:		The readout base structure for CLOCK_MONOTONIC
 * @tkr_raw:		The readout base structure for CLOCK_MONOTONIC_RAW
 * @xtime_sec:		Current CLOCK_REALTIME time in seconds
 * @ktime_sec:		Current CLOCK_MONOTONIC 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
 * @clock_was_set_seq:	The sequence number of clock was set events
 * @next_leap_ktime:	CLOCK_MONOTONIC time value of a pending leap-second
 * @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.
 * @last_warning:	Warning ratelimiter (DEBUG_TIMEKEEPING)
 * @underflow_seen:	Underflow warning flag (DEBUG_TIMEKEEPING)
 * @overflow_seen:	Overflow warning flag (DEBUG_TIMEKEEPING)
 *
 * 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_mono;
	struct tk_read_base	tkr_raw;
	u64			xtime_sec;
	unsigned long		ktime_sec;
	struct timespec64	wall_to_monotonic;
	ktime_t			offs_real;
	ktime_t			offs_boot;
	ktime_t			offs_tai;
	s32			tai_offset;
	unsigned int		clock_was_set_seq;
	ktime_t			next_leap_ktime;
	struct timespec64	raw_time;

	/* The following members are for timekeeping internal use */
	cycle_t			cycle_interval;
	u64			xtime_interval;
	s64			xtime_remainder;
	u32			raw_interval;
	/* 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;
	u32			ntp_error_shift;
	u32			ntp_err_mult;
#ifdef CONFIG_DEBUG_TIMEKEEPING
	long			last_warning;
	/*
	 * These simple flag variables are managed
	 * without locks, which is racy, but they are
	 * ok since we don't really care about being
	 * super precise about how many events were
	 * seen, just that a problem was observed.
	 */
	int			underflow_seen;
	int			overflow_seen;
#endif
};

#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,
				cycle_t cycle_last);
extern void update_vsyscall_tz(void);

#else

static inline void update_vsyscall(struct timekeeper *tk)
{
}
static inline void update_vsyscall_tz(void)
{
}
#endif

#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
Commit	Line	Data
d7b4202e JS	1	/*
	2	* You SHOULD NOT be including this unless you're vsyscall
	3	* handling code or timekeeping internal code!
	4	*/
	5
	6	#ifndef _LINUX_TIMEKEEPER_INTERNAL_H
	7	#define _LINUX_TIMEKEEPER_INTERNAL_H
	8
	9	#include <linux/clocksource.h>
	10	#include <linux/jiffies.h>
	11	#include <linux/time.h>
	12
d28ede83 TG	13	/**
	14	* struct tk_read_base - base structure for timekeeping readout
	15	* @clock: Current clocksource used for timekeeping.
	16	* @read: Read function of @clock
	17	* @mask: Bitmask for two's complement subtraction of non 64bit clocks
	18	* @cycle_last: @clock cycle value at last update
876e7881	19	* @mult: (NTP adjusted) multiplier for scaled math conversion
d28ede83 TG	20	* @shift: Shift value for scaled math conversion
d28ede83 TG	21	* @xtime_nsec: Shifted (fractional) nano seconds offset for readout
876e7881	22	* @base: ktime_t (nanoseconds) base time for readout
3fdb14fd	23	*
d28ede83 TG	24	* This struct has size 56 byte on 64 bit. Together with a seqcount it
d28ede83 TG	25	* occupies a single 64byte cache line.
3fdb14fd	26	*
d28ede83	27	* The struct is separate from struct timekeeper as it is also used
876e7881	28	* for a fast NMI safe accessors.
3fdb14fd	29	*/
d28ede83	30	struct tk_read_base {
d7b4202e	31	struct clocksource *clock;
6d3aadf3	32	cycle_t (read)(struct clocksource cs);
6d3aadf3	33	cycle_t mask;
4a0e6377	34	cycle_t cycle_last;
d7b4202e	35	u32 mult;
d7b4202e	36	u32 shift;
3fdb14fd	37	u64 xtime_nsec;
876e7881	38	ktime_t base;
d28ede83	39	};
7c032df5	40
d28ede83 TG	41	/**
d28ede83 TG	42	* struct timekeeper - Structure holding internal timekeeping values.
876e7881	43	* @tkr_mono: The readout base structure for CLOCK_MONOTONIC
4a4ad80d	44	* @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW
d28ede83	45	* @xtime_sec: Current CLOCK_REALTIME time in seconds
9e3680b1	46	* @ktime_sec: Current CLOCK_MONOTONIC time in seconds
d28ede83 TG	47	* @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset
	48	* @offs_real: Offset clock monotonic -> clock realtime
	49	* @offs_boot: Offset clock monotonic -> clock boottime
	50	* @offs_tai: Offset clock monotonic -> clock tai
	51	* @tai_offset: The current UTC to TAI offset in seconds
868a3e91	52	* @clock_was_set_seq: The sequence number of clock was set events
833f32d7	53	* @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second
d28ede83 TG	54	* @raw_time: Monotonic raw base time in timespec64 format
	55	* @cycle_interval: Number of clock cycles in one NTP interval
	56	* @xtime_interval: Number of clock shifted nano seconds in one NTP
	57	* interval.
	58	* @xtime_remainder: Shifted nano seconds left over when rounding
	59	* @cycle_interval
	60	* @raw_interval: Raw nano seconds accumulated per NTP interval.
	61	* @ntp_error: Difference between accumulated time and NTP time in ntp
	62	* shifted nano seconds.
	63	* @ntp_error_shift: Shift conversion between clock shifted nano seconds and
	64	* ntp shifted nano seconds.
57d05a93 JS	65	* @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING)
	66	* @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING)
	67	* @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING)
d28ede83 TG	68	*
	69	* Note: For timespec(64) based interfaces wall_to_monotonic is what
	70	* we need to add to xtime (or xtime corrected for sub jiffie times)
	71	* to get to monotonic time. Monotonic is pegged at zero at system
	72	* boot time, so wall_to_monotonic will be negative, however, we will
	73	* ALWAYS keep the tv_nsec part positive so we can use the usual
	74	* normalization.
	75	*
	76	* wall_to_monotonic is moved after resume from suspend for the
	77	* monotonic time not to jump. We need to add total_sleep_time to
	78	* wall_to_monotonic to get the real boot based time offset.
	79	*
	80	* wall_to_monotonic is no longer the boot time, getboottime must be
	81	* used instead.
	82	*/
	83	struct timekeeper {
876e7881	84	struct tk_read_base tkr_mono;
4a4ad80d	85	struct tk_read_base tkr_raw;
3fdb14fd	86	u64 xtime_sec;
9e3680b1	87	unsigned long ktime_sec;
3fdb14fd	88	struct timespec64 wall_to_monotonic;
3fdb14fd	89	ktime_t offs_real;
3fdb14fd	90	ktime_t offs_boot;
3fdb14fd	91	ktime_t offs_tai;
3fdb14fd	92	s32 tai_offset;
868a3e91	93	unsigned int clock_was_set_seq;
833f32d7	94	ktime_t next_leap_ktime;
3fdb14fd TG	95	struct timespec64 raw_time;
3fdb14fd TG	96
d28ede83	97	/* The following members are for timekeeping internal use */
d7b4202e	98	cycle_t cycle_interval;
d7b4202e	99	u64 xtime_interval;
d7b4202e	100	s64 xtime_remainder;
d7b4202e	101	u32 raw_interval;
375f45b5 JS	102	/* The ntp_tick_length() value currently being used.
	103	* This cached copy ensures we consistently apply the tick
	104	* length for an entire tick, as ntp_tick_length may change
	105	* mid-tick, and we don't want to apply that new value to
	106	* the tick in progress.
	107	*/
	108	u64 ntp_tick;
	109	/* Difference between accumulated time and NTP time in ntp
	110	* shifted nano seconds. */
d7b4202e	111	s64 ntp_error;
3fdb14fd	112	u32 ntp_error_shift;
dc491596	113	u32 ntp_err_mult;
57d05a93 JS	114	#ifdef CONFIG_DEBUG_TIMEKEEPING
	115	long last_warning;
	116	/*
	117	* These simple flag variables are managed
	118	* without locks, which is racy, but they are
	119	* ok since we don't really care about being
	120	* super precise about how many events were
	121	* seen, just that a problem was observed.
	122	*/
	123	int underflow_seen;
	124	int overflow_seen;
	125	#endif
d7b4202e	126	};
189374ae	127
576094b7 JS	128	#ifdef CONFIG_GENERIC_TIME_VSYSCALL
	129
	130	extern void update_vsyscall(struct timekeeper *tk);
	131	extern void update_vsyscall_tz(void);
189374ae	132
576094b7 JS	133	#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
	134
	135	extern void update_vsyscall_old(struct timespec ts, struct timespec wtm,
4a0e6377	136	struct clocksource *c, u32 mult,
953dec21	137	cycle_t cycle_last);
189374ae	138	extern void update_vsyscall_tz(void);
576094b7	139
189374ae	140	#else
576094b7 JS	141
576094b7 JS	142	static inline void update_vsyscall(struct timekeeper *tk)
189374ae JS	143	{
	144	}
	145	static inline void update_vsyscall_tz(void)
	146	{
	147	}
	148	#endif
	149
d7b4202e	150	#endif /* _LINUX_TIMEKEEPER_INTERNAL_H */