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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __VDSO_DATAPAGE_H | |
3 | #define __VDSO_DATAPAGE_H | |
4 | ||
361f8aee VF |
5 | #ifndef __ASSEMBLY__ |
6 | ||
8c59ab83 VF |
7 | #include <linux/compiler.h> |
8 | #include <uapi/linux/time.h> | |
9 | #include <uapi/linux/types.h> | |
10 | #include <uapi/asm-generic/errno-base.h> | |
11 | ||
12 | #include <vdso/bits.h> | |
13 | #include <vdso/clocksource.h> | |
14 | #include <vdso/ktime.h> | |
15 | #include <vdso/limits.h> | |
16 | #include <vdso/math64.h> | |
17 | #include <vdso/processor.h> | |
18 | #include <vdso/time.h> | |
19 | #include <vdso/time32.h> | |
20 | #include <vdso/time64.h> | |
361f8aee VF |
21 | |
22 | #define VDSO_BASES (CLOCK_TAI + 1) | |
23 | #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ | |
24 | BIT(CLOCK_MONOTONIC) | \ | |
25 | BIT(CLOCK_BOOTTIME) | \ | |
26 | BIT(CLOCK_TAI)) | |
27 | #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ | |
28 | BIT(CLOCK_MONOTONIC_COARSE)) | |
29 | #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) | |
30 | ||
31 | #define CS_HRES_COARSE 0 | |
32 | #define CS_RAW 1 | |
33 | #define CS_BASES (CS_RAW + 1) | |
34 | ||
35 | /** | |
36 | * struct vdso_timestamp - basetime per clock_id | |
37 | * @sec: seconds | |
38 | * @nsec: nanoseconds | |
39 | * | |
40 | * There is one vdso_timestamp object in vvar for each vDSO-accelerated | |
41 | * clock_id. For high-resolution clocks, this encodes the time | |
42 | * corresponding to vdso_data.cycle_last. For coarse clocks this encodes | |
43 | * the actual time. | |
44 | * | |
45 | * To be noticed that for highres clocks nsec is left-shifted by | |
46 | * vdso_data.cs[x].shift. | |
47 | */ | |
48 | struct vdso_timestamp { | |
49 | u64 sec; | |
50 | u64 nsec; | |
51 | }; | |
52 | ||
53 | /** | |
54 | * struct vdso_data - vdso datapage representation | |
55 | * @seq: timebase sequence counter | |
56 | * @clock_mode: clock mode | |
57 | * @cycle_last: timebase at clocksource init | |
58 | * @mask: clocksource mask | |
59 | * @mult: clocksource multiplier | |
60 | * @shift: clocksource shift | |
61 | * @basetime[clock_id]: basetime per clock_id | |
660fd04f | 62 | * @offset[clock_id]: time namespace offset per clock_id |
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63 | * @tz_minuteswest: minutes west of Greenwich |
64 | * @tz_dsttime: type of DST correction | |
65 | * @hrtimer_res: hrtimer resolution | |
66 | * @__unused: unused | |
67 | * | |
68 | * vdso_data will be accessed by 64 bit and compat code at the same time | |
69 | * so we should be careful before modifying this structure. | |
660fd04f TG |
70 | * |
71 | * @basetime is used to store the base time for the system wide time getter | |
72 | * VVAR page. | |
73 | * | |
74 | * @offset is used by the special time namespace VVAR pages which are | |
75 | * installed instead of the real VVAR page. These namespace pages must set | |
76 | * @seq to 1 and @clock_mode to VLOCK_TIMENS to force the code into the | |
77 | * time namespace slow path. The namespace aware functions retrieve the | |
78 | * real system wide VVAR page, read host time and add the per clock offset. | |
79 | * For clocks which are not affected by time namespace adjustment the | |
80 | * offset must be zero. | |
361f8aee VF |
81 | */ |
82 | struct vdso_data { | |
83 | u32 seq; | |
84 | ||
85 | s32 clock_mode; | |
86 | u64 cycle_last; | |
87 | u64 mask; | |
88 | u32 mult; | |
89 | u32 shift; | |
90 | ||
660fd04f TG |
91 | union { |
92 | struct vdso_timestamp basetime[VDSO_BASES]; | |
93 | struct timens_offset offset[VDSO_BASES]; | |
94 | }; | |
361f8aee VF |
95 | |
96 | s32 tz_minuteswest; | |
97 | s32 tz_dsttime; | |
98 | u32 hrtimer_res; | |
99 | u32 __unused; | |
100 | }; | |
101 | ||
102 | /* | |
103 | * We use the hidden visibility to prevent the compiler from generating a GOT | |
104 | * relocation. Not only is going through a GOT useless (the entry couldn't and | |
105 | * must not be overridden by another library), it does not even work: the linker | |
106 | * cannot generate an absolute address to the data page. | |
107 | * | |
108 | * With the hidden visibility, the compiler simply generates a PC-relative | |
109 | * relocation, and this is what we need. | |
110 | */ | |
111 | extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden"))); | |
112 | ||
8c59ab83 VF |
113 | /* |
114 | * The generic vDSO implementation requires that gettimeofday.h | |
115 | * provides: | |
116 | * - __arch_get_vdso_data(): to get the vdso datapage. | |
117 | * - __arch_get_hw_counter(): to get the hw counter based on the | |
118 | * clock_mode. | |
119 | * - gettimeofday_fallback(): fallback for gettimeofday. | |
120 | * - clock_gettime_fallback(): fallback for clock_gettime. | |
121 | * - clock_getres_fallback(): fallback for clock_getres. | |
122 | */ | |
123 | #ifdef ENABLE_COMPAT_VDSO | |
124 | #include <asm/vdso/compat_gettimeofday.h> | |
125 | #else | |
126 | #include <asm/vdso/gettimeofday.h> | |
127 | #endif /* ENABLE_COMPAT_VDSO */ | |
128 | ||
361f8aee VF |
129 | #endif /* !__ASSEMBLY__ */ |
130 | ||
361f8aee | 131 | #endif /* __VDSO_DATAPAGE_H */ |