1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * You SHOULD NOT be including this unless you're vsyscall |
4 | * handling code or timekeeping internal code! |
5 | */ |
6 | |
7 | #ifndef _LINUX_TIMEKEEPER_INTERNAL_H |
8 | #define _LINUX_TIMEKEEPER_INTERNAL_H |
9 | |
10 | #include <linux/clocksource.h> |
11 | #include <linux/jiffies.h> |
12 | #include <linux/time.h> |
13 | |
14 | /** |
15 | * struct tk_read_base - base structure for timekeeping readout |
16 | * @clock: Current clocksource used for timekeeping. |
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 | * @base_real: Nanoseconds base value for clock REALTIME readout |
24 | * |
25 | * This struct has size 56 byte on 64 bit. Together with a seqcount it |
26 | * occupies a single 64byte cache line. |
27 | * |
28 | * The struct is separate from struct timekeeper as it is also used |
29 | * for a fast NMI safe accessors. |
30 | * |
31 | * @base_real is for the fast NMI safe accessor to allow reading clock |
32 | * realtime from any context. |
33 | */ |
34 | struct tk_read_base { |
35 | struct clocksource *clock; |
36 | u64 mask; |
37 | u64 cycle_last; |
38 | u32 mult; |
39 | u32 shift; |
40 | u64 xtime_nsec; |
41 | ktime_t base; |
42 | u64 base_real; |
43 | }; |
44 | |
45 | /** |
46 | * struct timekeeper - Structure holding internal timekeeping values. |
47 | * @tkr_mono: The readout base structure for CLOCK_MONOTONIC |
48 | * @tkr_raw: The readout base structure for CLOCK_MONOTONIC_RAW |
49 | * @xtime_sec: Current CLOCK_REALTIME time in seconds |
50 | * @ktime_sec: Current CLOCK_MONOTONIC time in seconds |
51 | * @wall_to_monotonic: CLOCK_REALTIME to CLOCK_MONOTONIC offset |
52 | * @offs_real: Offset clock monotonic -> clock realtime |
53 | * @offs_boot: Offset clock monotonic -> clock boottime |
54 | * @offs_tai: Offset clock monotonic -> clock tai |
55 | * @tai_offset: The current UTC to TAI offset in seconds |
56 | * @clock_was_set_seq: The sequence number of clock was set events |
57 | * @cs_was_changed_seq: The sequence number of clocksource change events |
58 | * @next_leap_ktime: CLOCK_MONOTONIC time value of a pending leap-second |
59 | * @raw_sec: CLOCK_MONOTONIC_RAW time in seconds |
60 | * @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset |
61 | * @cycle_interval: Number of clock cycles in one NTP interval |
62 | * @xtime_interval: Number of clock shifted nano seconds in one NTP |
63 | * interval. |
64 | * @xtime_remainder: Shifted nano seconds left over when rounding |
65 | * @cycle_interval |
66 | * @raw_interval: Shifted raw nano seconds accumulated per NTP interval. |
67 | * @ntp_error: Difference between accumulated time and NTP time in ntp |
68 | * shifted nano seconds. |
69 | * @ntp_error_shift: Shift conversion between clock shifted nano seconds and |
70 | * ntp shifted nano seconds. |
71 | * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING) |
72 | * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING) |
73 | * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING) |
74 | * |
75 | * Note: For timespec(64) based interfaces wall_to_monotonic is what |
76 | * we need to add to xtime (or xtime corrected for sub jiffie times) |
77 | * to get to monotonic time. Monotonic is pegged at zero at system |
78 | * boot time, so wall_to_monotonic will be negative, however, we will |
79 | * ALWAYS keep the tv_nsec part positive so we can use the usual |
80 | * normalization. |
81 | * |
82 | * wall_to_monotonic is moved after resume from suspend for the |
83 | * monotonic time not to jump. We need to add total_sleep_time to |
84 | * wall_to_monotonic to get the real boot based time offset. |
85 | * |
86 | * wall_to_monotonic is no longer the boot time, getboottime must be |
87 | * used instead. |
88 | * |
89 | * @monotonic_to_boottime is a timespec64 representation of @offs_boot to |
90 | * accelerate the VDSO update for CLOCK_BOOTTIME. |
91 | */ |
92 | struct timekeeper { |
93 | struct tk_read_base tkr_mono; |
94 | struct tk_read_base tkr_raw; |
95 | u64 xtime_sec; |
96 | unsigned long ktime_sec; |
97 | struct timespec64 wall_to_monotonic; |
98 | ktime_t offs_real; |
99 | ktime_t offs_boot; |
100 | ktime_t offs_tai; |
101 | s32 tai_offset; |
102 | unsigned int clock_was_set_seq; |
103 | u8 cs_was_changed_seq; |
104 | ktime_t next_leap_ktime; |
105 | u64 raw_sec; |
106 | struct timespec64 monotonic_to_boot; |
107 | |
108 | /* The following members are for timekeeping internal use */ |
109 | u64 cycle_interval; |
110 | u64 xtime_interval; |
111 | s64 xtime_remainder; |
112 | u64 raw_interval; |
113 | /* The ntp_tick_length() value currently being used. |
114 | * This cached copy ensures we consistently apply the tick |
115 | * length for an entire tick, as ntp_tick_length may change |
116 | * mid-tick, and we don't want to apply that new value to |
117 | * the tick in progress. |
118 | */ |
119 | u64 ntp_tick; |
120 | /* Difference between accumulated time and NTP time in ntp |
121 | * shifted nano seconds. */ |
122 | s64 ntp_error; |
123 | u32 ntp_error_shift; |
124 | u32 ntp_err_mult; |
125 | /* Flag used to avoid updating NTP twice with same second */ |
126 | u32 skip_second_overflow; |
127 | #ifdef CONFIG_DEBUG_TIMEKEEPING |
128 | long last_warning; |
129 | /* |
130 | * These simple flag variables are managed |
131 | * without locks, which is racy, but they are |
132 | * ok since we don't really care about being |
133 | * super precise about how many events were |
134 | * seen, just that a problem was observed. |
135 | */ |
136 | int underflow_seen; |
137 | int overflow_seen; |
138 | #endif |
139 | }; |
140 | |
141 | #ifdef CONFIG_GENERIC_TIME_VSYSCALL |
142 | |
143 | extern void update_vsyscall(struct timekeeper *tk); |
144 | extern void update_vsyscall_tz(void); |
145 | |
146 | #else |
147 | |
148 | static inline void update_vsyscall(struct timekeeper *tk) |
149 | { |
150 | } |
151 | static inline void update_vsyscall_tz(void) |
152 | { |
153 | } |
154 | #endif |
155 | |
156 | #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */ |
157 | |