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 unsigned long long ret
= 0;
26 #ifndef CONFIG_X86_TSC
35 static __always_inline cycles_t
vget_cycles(void)
38 * We only do VDSOs on TSC capable CPUs, so this shouldn't
39 * access boot_cpu_data (which is not VDSO-safe):
41 #ifndef CONFIG_X86_TSC
45 return (cycles_t
)__native_read_tsc();
48 extern void tsc_init(void);
49 extern void mark_tsc_unstable(char *reason
);
50 extern int unsynchronized_tsc(void);
51 extern int check_tsc_unstable(void);
52 extern int check_tsc_disabled(void);
53 extern unsigned long native_calibrate_tsc(void);
55 extern int tsc_clocksource_reliable
;
58 * Boot-time check whether the TSCs are synchronized across
61 extern void check_tsc_sync_source(int cpu
);
62 extern void check_tsc_sync_target(void);
64 extern int notsc_setup(char *);
65 extern void tsc_save_sched_clock_state(void);
66 extern void tsc_restore_sched_clock_state(void);
68 #endif /* _ASM_X86_TSC_H */