1 /*
2 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
3 */
4
5 #ifndef _ASM_SPARC_VVAR_DATA_H
6 #define _ASM_SPARC_VVAR_DATA_H
7
8 #include <asm/clocksource.h>
9 #include <asm/processor.h>
10 #include <asm/barrier.h>
11 #include <linux/time.h>
12 #include <linux/types.h>
13
14 struct vvar_data {
15 unsigned int seq;
16
17 int vclock_mode;
18 struct { /* extract of a clocksource struct */
19 u64 cycle_last;
20 u64 mask;
21 int mult;
22 int shift;
23 } clock;
24 /* open coded 'struct timespec' */
25 u64 wall_time_sec;
26 u64 wall_time_snsec;
27 u64 monotonic_time_snsec;
28 u64 monotonic_time_sec;
29 u64 monotonic_time_coarse_sec;
30 u64 monotonic_time_coarse_nsec;
31 u64 wall_time_coarse_sec;
32 u64 wall_time_coarse_nsec;
33
34 int tz_minuteswest;
35 int tz_dsttime;
36 };
37
38 extern struct vvar_data *vvar_data;
39 extern int vdso_fix_stick;
40
41 static inline unsigned int vvar_read_begin(const struct vvar_data *s)
42 {
43 unsigned int ret;
44
45 repeat:
46 ret = READ_ONCE(s->seq);
47 if (unlikely(ret & 1)) {
48 cpu_relax();
49 goto repeat;
50 }
51 smp_rmb(); /* Finish all reads before we return seq */
52 return ret;
53 }
54
55 static inline int vvar_read_retry(const struct vvar_data *s,
56 unsigned int start)
57 {
58 smp_rmb(); /* Finish all reads before checking the value of seq */
59 return unlikely(s->seq != start);
60 }
61
62 static inline void vvar_write_begin(struct vvar_data *s)
63 {
64 ++s->seq;
65 smp_wmb(); /* Makes sure that increment of seq is reflected */
66 }
67
68 static inline void vvar_write_end(struct vvar_data *s)
69 {
70 smp_wmb(); /* Makes the value of seq current before we increment */
71 ++s->seq;
72 }
73
74
75 #endif /* _ASM_SPARC_VVAR_DATA_H */
76
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