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1965aae3 PA |
1 | #ifndef _ASM_X86_VGTOD_H |
2 | #define _ASM_X86_VGTOD_H | |
2aae950b | 3 | |
7c03156f | 4 | #include <linux/compiler.h> |
2aae950b AK |
5 | #include <linux/clocksource.h> |
6 | ||
7c03156f SS |
7 | #ifdef BUILD_VDSO32_64 |
8 | typedef u64 gtod_long_t; | |
9 | #else | |
10 | typedef unsigned long gtod_long_t; | |
11 | #endif | |
12 | /* | |
13 | * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time | |
14 | * so be carefull by modifying this structure. | |
15 | */ | |
2aae950b | 16 | struct vsyscall_gtod_data { |
7c03156f | 17 | unsigned seq; |
2aae950b | 18 | |
7c03156f SS |
19 | int vclock_mode; |
20 | cycle_t cycle_last; | |
21 | cycle_t mask; | |
22 | u32 mult; | |
23 | u32 shift; | |
91ec87d5 AL |
24 | |
25 | /* open coded 'struct timespec' */ | |
650ea024 | 26 | u64 wall_time_snsec; |
7c03156f SS |
27 | gtod_long_t wall_time_sec; |
28 | gtod_long_t monotonic_time_sec; | |
650ea024 | 29 | u64 monotonic_time_snsec; |
7c03156f SS |
30 | gtod_long_t wall_time_coarse_sec; |
31 | gtod_long_t wall_time_coarse_nsec; | |
32 | gtod_long_t monotonic_time_coarse_sec; | |
33 | gtod_long_t monotonic_time_coarse_nsec; | |
91ec87d5 | 34 | |
7c03156f SS |
35 | int tz_minuteswest; |
36 | int tz_dsttime; | |
2aae950b | 37 | }; |
2aae950b AK |
38 | extern struct vsyscall_gtod_data vsyscall_gtod_data; |
39 | ||
bd902c53 AL |
40 | extern int vclocks_used; |
41 | static inline bool vclock_was_used(int vclock) | |
42 | { | |
43 | return READ_ONCE(vclocks_used) & (1 << vclock); | |
44 | } | |
45 | ||
7c03156f SS |
46 | static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s) |
47 | { | |
48 | unsigned ret; | |
49 | ||
50 | repeat: | |
51 | ret = ACCESS_ONCE(s->seq); | |
52 | if (unlikely(ret & 1)) { | |
53 | cpu_relax(); | |
54 | goto repeat; | |
55 | } | |
56 | smp_rmb(); | |
57 | return ret; | |
58 | } | |
59 | ||
60 | static inline int gtod_read_retry(const struct vsyscall_gtod_data *s, | |
61 | unsigned start) | |
62 | { | |
63 | smp_rmb(); | |
64 | return unlikely(s->seq != start); | |
65 | } | |
66 | ||
67 | static inline void gtod_write_begin(struct vsyscall_gtod_data *s) | |
68 | { | |
69 | ++s->seq; | |
70 | smp_wmb(); | |
71 | } | |
72 | ||
73 | static inline void gtod_write_end(struct vsyscall_gtod_data *s) | |
74 | { | |
75 | smp_wmb(); | |
76 | ++s->seq; | |
77 | } | |
78 | ||
e76b027e AL |
79 | #ifdef CONFIG_X86_64 |
80 | ||
81 | #define VGETCPU_CPU_MASK 0xfff | |
82 | ||
83 | static inline unsigned int __getcpu(void) | |
84 | { | |
85 | unsigned int p; | |
86 | ||
87 | /* | |
88 | * Load per CPU data from GDT. LSL is faster than RDTSCP and | |
1ddf0b1b AL |
89 | * works on all CPUs. This is volatile so that it orders |
90 | * correctly wrt barrier() and to keep gcc from cleverly | |
91 | * hoisting it out of the calling function. | |
e76b027e | 92 | */ |
1ddf0b1b | 93 | asm volatile ("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG)); |
e76b027e AL |
94 | |
95 | return p; | |
96 | } | |
97 | ||
98 | #endif /* CONFIG_X86_64 */ | |
99 | ||
1965aae3 | 100 | #endif /* _ASM_X86_VGTOD_H */ |