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
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
19 * @mult: (NTP adjusted) multiplier for scaled math conversion
20 * @shift: Shift value for scaled math conversion
21 * @xtime_nsec: Shifted (fractional) nano seconds offset for readout
22 * @base: ktime_t (nanoseconds) base time for readout
23 *
24 * This struct has size 56 byte on 64 bit. Together with a seqcount it
25 * occupies a single 64byte cache line.
26 *
27 * The struct is separate from struct timekeeper as it is also used
28 * for a fast NMI safe accessors.
29 */
30 struct tk_read_base {
31 struct clocksource *clock;
32 cycle_t (*read)(struct clocksource *cs);
33 cycle_t mask;
34 cycle_t cycle_last;
35 u32 mult;
36 u32 shift;
37 u64 xtime_nsec;
38 ktime_t base;
39 };
40
41 /**
42 * struct timekeeper - Structure holding internal timekeeping values.
43 * @tkr_mono: The readout base structure for CLOCK_MONOTONIC
44 * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW
45 * @xtime_sec: Current CLOCK_REALTIME time in seconds
46 * @ktime_sec: Current CLOCK_MONOTONIC time in seconds
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
52 * @raw_time: Monotonic raw base time in timespec64 format
53 * @cycle_interval: Number of clock cycles in one NTP interval
54 * @xtime_interval: Number of clock shifted nano seconds in one NTP
55 * interval.
56 * @xtime_remainder: Shifted nano seconds left over when rounding
57 * @cycle_interval
58 * @raw_interval: Raw nano seconds accumulated per NTP interval.
59 * @ntp_error: Difference between accumulated time and NTP time in ntp
60 * shifted nano seconds.
61 * @ntp_error_shift: Shift conversion between clock shifted nano seconds and
62 * ntp shifted nano seconds.
63 *
64 * Note: For timespec(64) based interfaces wall_to_monotonic is what
65 * we need to add to xtime (or xtime corrected for sub jiffie times)
66 * to get to monotonic time. Monotonic is pegged at zero at system
67 * boot time, so wall_to_monotonic will be negative, however, we will
68 * ALWAYS keep the tv_nsec part positive so we can use the usual
69 * normalization.
70 *
71 * wall_to_monotonic is moved after resume from suspend for the
72 * monotonic time not to jump. We need to add total_sleep_time to
73 * wall_to_monotonic to get the real boot based time offset.
74 *
75 * wall_to_monotonic is no longer the boot time, getboottime must be
76 * used instead.
77 */
78 struct timekeeper {
79 struct tk_read_base tkr_mono;
80 struct tk_read_base tkr_raw;
81 u64 xtime_sec;
82 unsigned long ktime_sec;
83 struct timespec64 wall_to_monotonic;
84 ktime_t offs_real;
85 ktime_t offs_boot;
86 ktime_t offs_tai;
87 s32 tai_offset;
88 struct timespec64 raw_time;
89
90 /* The following members are for timekeeping internal use */
91 cycle_t cycle_interval;
92 u64 xtime_interval;
93 s64 xtime_remainder;
94 u32 raw_interval;
95 /* The ntp_tick_length() value currently being used.
96 * This cached copy ensures we consistently apply the tick
97 * length for an entire tick, as ntp_tick_length may change
98 * mid-tick, and we don't want to apply that new value to
99 * the tick in progress.
100 */
101 u64 ntp_tick;
102 /* Difference between accumulated time and NTP time in ntp
103 * shifted nano seconds. */
104 s64 ntp_error;
105 u32 ntp_error_shift;
106 u32 ntp_err_mult;
107 };
108
109 #ifdef CONFIG_GENERIC_TIME_VSYSCALL
110
111 extern void update_vsyscall(struct timekeeper *tk);
112 extern void update_vsyscall_tz(void);
113
114 #elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
115
116 extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
117 struct clocksource *c, u32 mult,
118 cycle_t cycle_last);
119 extern void update_vsyscall_tz(void);
120
121 #else
122
update_vsyscall(struct timekeeper * tk)123 static inline void update_vsyscall(struct timekeeper *tk)
124 {
125 }
update_vsyscall_tz(void)126 static inline void update_vsyscall_tz(void)
127 {
128 }
129 #endif
130
131 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
132