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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * x86 TSC related functions
3 */
4#ifndef _ASM_X86_TSC_H
5#define _ASM_X86_TSC_H
6
7#include <asm/processor.h>
8
9#define NS_SCALE 10 /* 2^10, carefully chosen */
10#define US_SCALE 32 /* 2^32, arbitralrily chosen */
11
12/*
13 * Standard way to access the cycle counter.
14 */
15typedef unsigned long long cycles_t;
16
17extern unsigned int cpu_khz;
18extern unsigned int tsc_khz;
19
20extern void disable_TSC(void);
21
22static inline cycles_t get_cycles(void)
23{
24 unsigned long long ret = 0;
25
26#ifndef CONFIG_X86_TSC
27 if (!cpu_has_tsc)
28 return 0;
29#endif
30 rdtscll(ret);
31
32 return ret;
33}
34
35static __always_inline cycles_t vget_cycles(void)
36{
37 /*
38 * We only do VDSOs on TSC capable CPUs, so this shouldnt
39 * access boot_cpu_data (which is not VDSO-safe):
40 */
41#ifndef CONFIG_X86_TSC
42 if (!cpu_has_tsc)
43 return 0;
44#endif
45 return (cycles_t)__native_read_tsc();
46}
47
48extern void tsc_init(void);
49extern void mark_tsc_unstable(char *reason);
50extern int unsynchronized_tsc(void);
51int check_tsc_unstable(void);
52
53/*
54 * Boot-time check whether the TSCs are synchronized across
55 * all CPUs/cores:
56 */
57extern void check_tsc_sync_source(int cpu);
58extern void check_tsc_sync_target(void);
59
60extern int notsc_setup(char *);
61
62#endif /* _ASM_X86_TSC_H */