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/*
* linux/include/asm-x86_64/tsc.h
*
* x86_64 TSC related functions
*/
#ifndef _ASM_x86_64_TSC_H
#define _ASM_x86_64_TSC_H
#include <asm/processor.h>
/*
* Standard way to access the cycle counter.
*/
typedef unsigned long long cycles_t;
extern unsigned int cpu_khz;
extern unsigned int tsc_khz;
static inline cycles_t get_cycles(void)
{
unsigned long long ret = 0;
#ifndef CONFIG_X86_TSC
if (!cpu_has_tsc)
return 0;
#endif
#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
rdtscll(ret);
#endif
return ret;
}
/* Like get_cycles, but make sure the CPU is synchronized. */
static __always_inline cycles_t get_cycles_sync(void)
{
unsigned long long ret;
#ifdef X86_FEATURE_SYNC_RDTSC
unsigned eax;
/*
* Don't do an additional sync on CPUs where we know
* RDTSC is already synchronous:
*/
alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC,
"=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
#else
sync_core();
#endif
rdtscll(ret);
return ret;
}
extern void tsc_init(void);
extern void mark_tsc_unstable(void);
extern int unsynchronized_tsc(void);
/*
* Boot-time check whether the TSCs are synchronized across
* all CPUs/cores:
*/
extern void check_tsc_sync_source(int cpu);
extern void check_tsc_sync_target(void);
#endif
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