include/asm-x86_64/timex.h

/*
 * linux/include/asm-x86_64/timex.h
 *
 * x86-64 architecture timex specifications
 */
#ifndef _ASMx8664_TIMEX_H
#define _ASMx8664_TIMEX_H

#include <asm/8253pit.h>
#include <asm/msr.h>
#include <asm/vsyscall.h>
#include <asm/hpet.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <linux/compiler.h>

#define CLOCK_TICK_RATE	PIT_TICK_RATE	/* Underlying HZ */

typedef unsigned long long cycles_t;

static inline cycles_t get_cycles (void)
{
	unsigned long long ret;

	rdtscll(ret);
	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;
	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");
	rdtscll(ret);
	return ret;
}

extern unsigned int cpu_khz;

extern int read_current_timer(unsigned long *timer_value);
#define ARCH_HAS_READ_CURRENT_TIMER	1

extern struct vxtime_data vxtime;

#endif