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git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - kernel/time/vsyscall.c
1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright 2019 ARM Ltd.
5 * Generic implementation of update_vsyscall and update_vsyscall_tz.
7 * Based on the x86 specific implementation.
10 #include <linux/hrtimer.h>
11 #include <linux/timekeeper_internal.h>
12 #include <vdso/datapage.h>
13 #include <vdso/helpers.h>
14 #include <vdso/vsyscall.h>
16 static inline void update_vdso_data(struct vdso_data
*vdata
,
17 struct timekeeper
*tk
)
19 struct vdso_timestamp
*vdso_ts
;
22 vdata
[CS_HRES_COARSE
].cycle_last
= tk
->tkr_mono
.cycle_last
;
23 vdata
[CS_HRES_COARSE
].mask
= tk
->tkr_mono
.mask
;
24 vdata
[CS_HRES_COARSE
].mult
= tk
->tkr_mono
.mult
;
25 vdata
[CS_HRES_COARSE
].shift
= tk
->tkr_mono
.shift
;
26 vdata
[CS_RAW
].cycle_last
= tk
->tkr_raw
.cycle_last
;
27 vdata
[CS_RAW
].mask
= tk
->tkr_raw
.mask
;
28 vdata
[CS_RAW
].mult
= tk
->tkr_raw
.mult
;
29 vdata
[CS_RAW
].shift
= tk
->tkr_raw
.shift
;
32 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_REALTIME
];
33 vdso_ts
->sec
= tk
->xtime_sec
;
34 vdso_ts
->nsec
= tk
->tkr_mono
.xtime_nsec
;
37 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_MONOTONIC
];
38 vdso_ts
->sec
= tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
;
40 nsec
= tk
->tkr_mono
.xtime_nsec
;
41 nsec
+= ((u64
)tk
->wall_to_monotonic
.tv_nsec
<< tk
->tkr_mono
.shift
);
42 while (nsec
>= (((u64
)NSEC_PER_SEC
) << tk
->tkr_mono
.shift
)) {
43 nsec
-= (((u64
)NSEC_PER_SEC
) << tk
->tkr_mono
.shift
);
48 /* Copy MONOTONIC time for BOOTTIME */
50 /* Add the boot offset */
51 sec
+= tk
->monotonic_to_boot
.tv_sec
;
52 nsec
+= (u64
)tk
->monotonic_to_boot
.tv_nsec
<< tk
->tkr_mono
.shift
;
55 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_BOOTTIME
];
58 while (nsec
>= (((u64
)NSEC_PER_SEC
) << tk
->tkr_mono
.shift
)) {
59 nsec
-= (((u64
)NSEC_PER_SEC
) << tk
->tkr_mono
.shift
);
64 /* CLOCK_MONOTONIC_RAW */
65 vdso_ts
= &vdata
[CS_RAW
].basetime
[CLOCK_MONOTONIC_RAW
];
66 vdso_ts
->sec
= tk
->raw_sec
;
67 vdso_ts
->nsec
= tk
->tkr_raw
.xtime_nsec
;
70 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_TAI
];
71 vdso_ts
->sec
= tk
->xtime_sec
+ (s64
)tk
->tai_offset
;
72 vdso_ts
->nsec
= tk
->tkr_mono
.xtime_nsec
;
75 * Read without the seqlock held by clock_getres().
76 * Note: No need to have a second copy.
78 WRITE_ONCE(vdata
[CS_HRES_COARSE
].hrtimer_res
, hrtimer_resolution
);
81 void update_vsyscall(struct timekeeper
*tk
)
83 struct vdso_data
*vdata
= __arch_get_k_vdso_data();
84 struct vdso_timestamp
*vdso_ts
;
87 if (__arch_update_vdso_data()) {
89 * Some architectures might want to skip the update of the
95 /* copy vsyscall data */
96 vdso_write_begin(vdata
);
98 vdata
[CS_HRES_COARSE
].clock_mode
= __arch_get_clock_mode(tk
);
99 vdata
[CS_RAW
].clock_mode
= __arch_get_clock_mode(tk
);
101 /* CLOCK_REALTIME_COARSE */
102 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_REALTIME_COARSE
];
103 vdso_ts
->sec
= tk
->xtime_sec
;
104 vdso_ts
->nsec
= tk
->tkr_mono
.xtime_nsec
>> tk
->tkr_mono
.shift
;
106 /* CLOCK_MONOTONIC_COARSE */
107 vdso_ts
= &vdata
[CS_HRES_COARSE
].basetime
[CLOCK_MONOTONIC_COARSE
];
108 vdso_ts
->sec
= tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
;
109 nsec
= tk
->tkr_mono
.xtime_nsec
>> tk
->tkr_mono
.shift
;
110 nsec
= nsec
+ tk
->wall_to_monotonic
.tv_nsec
;
111 vdso_ts
->sec
+= __iter_div_u64_rem(nsec
, NSEC_PER_SEC
, &vdso_ts
->nsec
);
113 if (__arch_use_vsyscall(vdata
))
114 update_vdso_data(vdata
, tk
);
116 __arch_update_vsyscall(vdata
, tk
);
118 vdso_write_end(vdata
);
120 __arch_sync_vdso_data(vdata
);
123 void update_vsyscall_tz(void)
125 struct vdso_data
*vdata
= __arch_get_k_vdso_data();
127 if (__arch_use_vsyscall(vdata
)) {
128 vdata
[CS_HRES_COARSE
].tz_minuteswest
= sys_tz
.tz_minuteswest
;
129 vdata
[CS_HRES_COARSE
].tz_dsttime
= sys_tz
.tz_dsttime
;
132 __arch_sync_vdso_data(vdata
);