2 * x86 TSC related functions
7 #include <asm/processor.h>
9 #define NS_SCALE 10 /* 2^10, carefully chosen */
10 #define US_SCALE 32 /* 2^32, arbitralrily chosen */
13 * Standard way to access the cycle counter.
15 typedef unsigned long long cycles_t;
17 extern unsigned int cpu_khz;
18 extern unsigned int tsc_khz;
20 extern void disable_TSC(void);
22 static inline cycles_t get_cycles(void)
24 if (!IS_ENABLED(CONFIG_X86_TSC) &&
25 !cpu_feature_enabled(X86_FEATURE_TSC))
29 #define get_cycles get_cycles
31 extern struct system_counterval_t convert_art_to_tsc(cycle_t art);
33 extern void tsc_init(void);
34 extern void mark_tsc_unstable(char *reason);
35 extern int unsynchronized_tsc(void);
36 extern int check_tsc_unstable(void);
37 extern unsigned long native_calibrate_cpu(void);
38 extern unsigned long native_calibrate_tsc(void);
39 extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
41 extern int tsc_clocksource_reliable;
44 * Boot-time check whether the TSCs are synchronized across
47 extern void check_tsc_sync_source(int cpu);
48 extern void check_tsc_sync_target(void);
50 extern int notsc_setup(char *);
51 extern void tsc_save_sched_clock_state(void);
52 extern void tsc_restore_sched_clock_state(void);
54 unsigned long cpu_khz_from_msr(void);
56 #endif /* _ASM_X86_TSC_H */