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); 51extern int check_tsc_unstable(void); 52extern unsigned long native_calibrate_tsc(void); 53 54/* 55 * Boot-time check whether the TSCs are synchronized across 56 * all CPUs/cores: 57 */ 58extern void check_tsc_sync_source(int cpu); 59extern void check_tsc_sync_target(void); 60 61extern int notsc_setup(char *); 62extern void save_sched_clock_state(void); 63extern void restore_sched_clock_state(void); 64 65#endif /* _ASM_X86_TSC_H */ 66