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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#ifndef CONFIG_X86_TSC
25 if (!boot_cpu_has(X86_FEATURE_TSC))
26 return 0;
27#endif
28
29 return rdtsc();
30}
31
32extern struct system_counterval_t convert_art_to_tsc(cycle_t art);
33
34extern void tsc_init(void);
35extern void mark_tsc_unstable(char *reason);
36extern int unsynchronized_tsc(void);
37extern int check_tsc_unstable(void);
38extern int check_tsc_disabled(void);
39extern unsigned long native_calibrate_tsc(void);
40extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
41
42extern int tsc_clocksource_reliable;
43
44/*
45 * Boot-time check whether the TSCs are synchronized across
46 * all CPUs/cores:
47 */
48extern void check_tsc_sync_source(int cpu);
49extern void check_tsc_sync_target(void);
50
51extern int notsc_setup(char *);
52extern void tsc_save_sched_clock_state(void);
53extern void tsc_restore_sched_clock_state(void);
54
55/* MSR based TSC calibration for Intel Atom SoC platforms */
56unsigned long try_msr_calibrate_tsc(void);
57
58#endif /* _ASM_X86_TSC_H */