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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 ARM Ltd.
4 *
5 * Generic implementation of update_vsyscall and update_vsyscall_tz.
6 *
7 * Based on the x86 specific implementation.
8 */
9
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>
15
16#include "timekeeping_internal.h"
17
18static inline void update_vdso_data(struct vdso_data *vdata,
19 struct timekeeper *tk)
20{
21 struct vdso_timestamp *vdso_ts;
22 u64 nsec, sec;
23
24 vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
25 vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
26 vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
27 vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
28 vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
29 vdata[CS_RAW].mask = tk->tkr_raw.mask;
30 vdata[CS_RAW].mult = tk->tkr_raw.mult;
31 vdata[CS_RAW].shift = tk->tkr_raw.shift;
32
33 /* CLOCK_MONOTONIC */
34 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
35 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
36
37 nsec = tk->tkr_mono.xtime_nsec;
38 nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
39 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
40 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
41 vdso_ts->sec++;
42 }
43 vdso_ts->nsec = nsec;
44
45 /* Copy MONOTONIC time for BOOTTIME */
46 sec = vdso_ts->sec;
47 /* Add the boot offset */
48 sec += tk->monotonic_to_boot.tv_sec;
49 nsec += (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift;
50
51 /* CLOCK_BOOTTIME */
52 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
53 vdso_ts->sec = sec;
54
55 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
56 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
57 vdso_ts->sec++;
58 }
59 vdso_ts->nsec = nsec;
60
61 /* CLOCK_MONOTONIC_RAW */
62 vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
63 vdso_ts->sec = tk->raw_sec;
64 vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
65
66 /* CLOCK_TAI */
67 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
68 vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
69 vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
70}
71
72void update_vsyscall(struct timekeeper *tk)
73{
74 struct vdso_data *vdata = __arch_get_k_vdso_data();
75 struct vdso_timestamp *vdso_ts;
76 s32 clock_mode;
77 u64 nsec;
78
79 /* copy vsyscall data */
80 vdso_write_begin(vdata);
81
82 clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
83 vdata[CS_HRES_COARSE].clock_mode = clock_mode;
84 vdata[CS_RAW].clock_mode = clock_mode;
85
86 /* CLOCK_REALTIME also required for time() */
87 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
88 vdso_ts->sec = tk->xtime_sec;
89 vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
90
91 /* CLOCK_REALTIME_COARSE */
92 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
93 vdso_ts->sec = tk->xtime_sec;
94 vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
95
96 /* CLOCK_MONOTONIC_COARSE */
97 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
98 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
99 nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
100 nsec = nsec + tk->wall_to_monotonic.tv_nsec;
101 vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
102
103 /*
104 * Read without the seqlock held by clock_getres().
105 * Note: No need to have a second copy.
106 */
107 WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
108
109 /*
110 * If the current clocksource is not VDSO capable, then spare the
111 * update of the high resolution parts.
112 */
113 if (clock_mode != VDSO_CLOCKMODE_NONE)
114 update_vdso_data(vdata, tk);
115
116 __arch_update_vsyscall(vdata, tk);
117
118 vdso_write_end(vdata);
119
120 __arch_sync_vdso_data(vdata);
121}
122
123void update_vsyscall_tz(void)
124{
125 struct vdso_data *vdata = __arch_get_k_vdso_data();
126
127 vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
128 vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
129
130 __arch_sync_vdso_data(vdata);
131}
132
133/**
134 * vdso_update_begin - Start of a VDSO update section
135 *
136 * Allows architecture code to safely update the architecture specific VDSO
137 * data. Disables interrupts, acquires timekeeper lock to serialize against
138 * concurrent updates from timekeeping and invalidates the VDSO data
139 * sequence counter to prevent concurrent readers from accessing
140 * inconsistent data.
141 *
142 * Returns: Saved interrupt flags which need to be handed in to
143 * vdso_update_end().
144 */
145unsigned long vdso_update_begin(void)
146{
147 struct vdso_data *vdata = __arch_get_k_vdso_data();
148 unsigned long flags;
149
150 raw_spin_lock_irqsave(&timekeeper_lock, flags);
151 vdso_write_begin(vdata);
152 return flags;
153}
154
155/**
156 * vdso_update_end - End of a VDSO update section
157 * @flags: Interrupt flags as returned from vdso_update_begin()
158 *
159 * Pairs with vdso_update_begin(). Marks vdso data consistent, invokes data
160 * synchronization if the architecture requires it, drops timekeeper lock
161 * and restores interrupt flags.
162 */
163void vdso_update_end(unsigned long flags)
164{
165 struct vdso_data *vdata = __arch_get_k_vdso_data();
166
167 vdso_write_end(vdata);
168 __arch_sync_vdso_data(vdata);
169 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
170}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 ARM Ltd.
4 *
5 * Generic implementation of update_vsyscall and update_vsyscall_tz.
6 *
7 * Based on the x86 specific implementation.
8 */
9
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>
15
16#include "timekeeping_internal.h"
17
18static inline void update_vdso_data(struct vdso_data *vdata,
19 struct timekeeper *tk)
20{
21 struct vdso_timestamp *vdso_ts;
22 u64 nsec, sec;
23
24 vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
25#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
26 vdata[CS_HRES_COARSE].max_cycles = tk->tkr_mono.clock->max_cycles;
27#endif
28 vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
29 vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
30 vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
31 vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
32#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
33 vdata[CS_RAW].max_cycles = tk->tkr_raw.clock->max_cycles;
34#endif
35 vdata[CS_RAW].mask = tk->tkr_raw.mask;
36 vdata[CS_RAW].mult = tk->tkr_raw.mult;
37 vdata[CS_RAW].shift = tk->tkr_raw.shift;
38
39 /* CLOCK_MONOTONIC */
40 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
41 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
42
43 nsec = tk->tkr_mono.xtime_nsec;
44 nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
45 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
46 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
47 vdso_ts->sec++;
48 }
49 vdso_ts->nsec = nsec;
50
51 /* Copy MONOTONIC time for BOOTTIME */
52 sec = vdso_ts->sec;
53 /* Add the boot offset */
54 sec += tk->monotonic_to_boot.tv_sec;
55 nsec += (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift;
56
57 /* CLOCK_BOOTTIME */
58 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
59 vdso_ts->sec = sec;
60
61 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
62 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
63 vdso_ts->sec++;
64 }
65 vdso_ts->nsec = nsec;
66
67 /* CLOCK_MONOTONIC_RAW */
68 vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
69 vdso_ts->sec = tk->raw_sec;
70 vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
71
72 /* CLOCK_TAI */
73 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
74 vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
75 vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
76}
77
78void update_vsyscall(struct timekeeper *tk)
79{
80 struct vdso_data *vdata = __arch_get_k_vdso_data();
81 struct vdso_timestamp *vdso_ts;
82 s32 clock_mode;
83 u64 nsec;
84
85 /* copy vsyscall data */
86 vdso_write_begin(vdata);
87
88 clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
89 vdata[CS_HRES_COARSE].clock_mode = clock_mode;
90 vdata[CS_RAW].clock_mode = clock_mode;
91
92 /* CLOCK_REALTIME also required for time() */
93 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
94 vdso_ts->sec = tk->xtime_sec;
95 vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
96
97 /* CLOCK_REALTIME_COARSE */
98 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
99 vdso_ts->sec = tk->xtime_sec;
100 vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
101
102 /* CLOCK_MONOTONIC_COARSE */
103 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
104 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
105 nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
106 nsec = nsec + tk->wall_to_monotonic.tv_nsec;
107 vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
108
109 /*
110 * Read without the seqlock held by clock_getres().
111 * Note: No need to have a second copy.
112 */
113 WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
114
115 /*
116 * If the current clocksource is not VDSO capable, then spare the
117 * update of the high resolution parts.
118 */
119 if (clock_mode != VDSO_CLOCKMODE_NONE)
120 update_vdso_data(vdata, tk);
121
122 __arch_update_vsyscall(vdata);
123
124 vdso_write_end(vdata);
125
126 __arch_sync_vdso_data(vdata);
127}
128
129void update_vsyscall_tz(void)
130{
131 struct vdso_data *vdata = __arch_get_k_vdso_data();
132
133 vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
134 vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
135
136 __arch_sync_vdso_data(vdata);
137}
138
139/**
140 * vdso_update_begin - Start of a VDSO update section
141 *
142 * Allows architecture code to safely update the architecture specific VDSO
143 * data. Disables interrupts, acquires timekeeper lock to serialize against
144 * concurrent updates from timekeeping and invalidates the VDSO data
145 * sequence counter to prevent concurrent readers from accessing
146 * inconsistent data.
147 *
148 * Returns: Saved interrupt flags which need to be handed in to
149 * vdso_update_end().
150 */
151unsigned long vdso_update_begin(void)
152{
153 struct vdso_data *vdata = __arch_get_k_vdso_data();
154 unsigned long flags = timekeeper_lock_irqsave();
155
156 vdso_write_begin(vdata);
157 return flags;
158}
159
160/**
161 * vdso_update_end - End of a VDSO update section
162 * @flags: Interrupt flags as returned from vdso_update_begin()
163 *
164 * Pairs with vdso_update_begin(). Marks vdso data consistent, invokes data
165 * synchronization if the architecture requires it, drops timekeeper lock
166 * and restores interrupt flags.
167 */
168void vdso_update_end(unsigned long flags)
169{
170 struct vdso_data *vdata = __arch_get_k_vdso_data();
171
172 vdso_write_end(vdata);
173 __arch_sync_vdso_data(vdata);
174 timekeeper_unlock_irqrestore(flags);
175}