1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __VDSO_DATAPAGE_H |
3 | #define __VDSO_DATAPAGE_H |
4 | |
5 | #ifndef __ASSEMBLY__ |
6 | |
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> |
21 | |
22 | #ifdef CONFIG_ARCH_HAS_VDSO_DATA |
23 | #include <asm/vdso/data.h> |
24 | #else |
25 | struct arch_vdso_data {}; |
26 | #endif |
27 | |
28 | #define VDSO_BASES (CLOCK_TAI + 1) |
29 | #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ |
30 | BIT(CLOCK_MONOTONIC) | \ |
31 | BIT(CLOCK_BOOTTIME) | \ |
32 | BIT(CLOCK_TAI)) |
33 | #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ |
34 | BIT(CLOCK_MONOTONIC_COARSE)) |
35 | #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) |
36 | |
37 | #define CS_HRES_COARSE 0 |
38 | #define CS_RAW 1 |
39 | #define CS_BASES (CS_RAW + 1) |
40 | |
41 | /** |
42 | * struct vdso_timestamp - basetime per clock_id |
43 | * @sec: seconds |
44 | * @nsec: nanoseconds |
45 | * |
46 | * There is one vdso_timestamp object in vvar for each vDSO-accelerated |
47 | * clock_id. For high-resolution clocks, this encodes the time |
48 | * corresponding to vdso_data.cycle_last. For coarse clocks this encodes |
49 | * the actual time. |
50 | * |
51 | * To be noticed that for highres clocks nsec is left-shifted by |
52 | * vdso_data.cs[x].shift. |
53 | */ |
54 | struct vdso_timestamp { |
55 | u64 sec; |
56 | u64 nsec; |
57 | }; |
58 | |
59 | /** |
60 | * struct vdso_data - vdso datapage representation |
61 | * @seq: timebase sequence counter |
62 | * @clock_mode: clock mode |
63 | * @cycle_last: timebase at clocksource init |
64 | * @mask: clocksource mask |
65 | * @mult: clocksource multiplier |
66 | * @shift: clocksource shift |
67 | * @basetime[clock_id]: basetime per clock_id |
68 | * @offset[clock_id]: time namespace offset per clock_id |
69 | * @tz_minuteswest: minutes west of Greenwich |
70 | * @tz_dsttime: type of DST correction |
71 | * @hrtimer_res: hrtimer resolution |
72 | * @__unused: unused |
73 | * @arch_data: architecture specific data (optional, defaults |
74 | * to an empty struct) |
75 | * |
76 | * vdso_data will be accessed by 64 bit and compat code at the same time |
77 | * so we should be careful before modifying this structure. |
78 | * |
79 | * @basetime is used to store the base time for the system wide time getter |
80 | * VVAR page. |
81 | * |
82 | * @offset is used by the special time namespace VVAR pages which are |
83 | * installed instead of the real VVAR page. These namespace pages must set |
84 | * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into |
85 | * the time namespace slow path. The namespace aware functions retrieve the |
86 | * real system wide VVAR page, read host time and add the per clock offset. |
87 | * For clocks which are not affected by time namespace adjustment the |
88 | * offset must be zero. |
89 | */ |
90 | struct vdso_data { |
91 | u32 seq; |
92 | |
93 | s32 clock_mode; |
94 | u64 cycle_last; |
95 | u64 mask; |
96 | u32 mult; |
97 | u32 shift; |
98 | |
99 | union { |
100 | struct vdso_timestamp basetime[VDSO_BASES]; |
101 | struct timens_offset offset[VDSO_BASES]; |
102 | }; |
103 | |
104 | s32 tz_minuteswest; |
105 | s32 tz_dsttime; |
106 | u32 hrtimer_res; |
107 | u32 __unused; |
108 | |
109 | struct arch_vdso_data arch_data; |
110 | }; |
111 | |
112 | /* |
113 | * We use the hidden visibility to prevent the compiler from generating a GOT |
114 | * relocation. Not only is going through a GOT useless (the entry couldn't and |
115 | * must not be overridden by another library), it does not even work: the linker |
116 | * cannot generate an absolute address to the data page. |
117 | * |
118 | * With the hidden visibility, the compiler simply generates a PC-relative |
119 | * relocation, and this is what we need. |
120 | */ |
121 | extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden" ))); |
122 | extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden" ))); |
123 | |
124 | /* |
125 | * The generic vDSO implementation requires that gettimeofday.h |
126 | * provides: |
127 | * - __arch_get_vdso_data(): to get the vdso datapage. |
128 | * - __arch_get_hw_counter(): to get the hw counter based on the |
129 | * clock_mode. |
130 | * - gettimeofday_fallback(): fallback for gettimeofday. |
131 | * - clock_gettime_fallback(): fallback for clock_gettime. |
132 | * - clock_getres_fallback(): fallback for clock_getres. |
133 | */ |
134 | #ifdef ENABLE_COMPAT_VDSO |
135 | #include <asm/vdso/compat_gettimeofday.h> |
136 | #else |
137 | #include <asm/vdso/gettimeofday.h> |
138 | #endif /* ENABLE_COMPAT_VDSO */ |
139 | |
140 | #endif /* !__ASSEMBLY__ */ |
141 | |
142 | #endif /* __VDSO_DATAPAGE_H */ |
143 | |