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