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/* -*- Mode:C; c-basic-offset:4; tab-width:4 -*-
****************************************************************************
* (C) 2002 - Rolf Neugebauer - Intel Research Cambridge
****************************************************************************
*
* File: time.h
* Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
* Changes:
*
* Date: Nov 2002
*
* Environment: Xen Hypervisor
* Description: Architecture dependent definition of time variables
*
****************************************************************************
* $Id: h-insert.h,v 1.4 2002/11/08 16:03:55 rn Exp $
****************************************************************************
*/
#ifndef _ASM_TIME_H_
#define _ASM_TIME_H_
#include <asm/types.h>
#include <asm/msr.h>
/*
* Cycle Counter Time
*/
typedef u64 cc_time_t;
static inline cc_time_t get_cc_time()
{
u64 ret;
rdtscll(ret);
return ret;
}
/*
* System Time
*/
typedef s64 s_time_t; /* System time */
extern u32 stime_pcc; /* cycle counter value at last timer irq */
extern s_time_t stime_now; /* time in ns at last timer IRQ */
extern u32 stime_scale; /* scale factur for converting cc to ns */
/*
* This is the Nemesis implementation.
* The variables are all set in apic.c
* Every timer IRQ time_now and time_pcc is set to the current values
* At callibration time_scale is set
*/
static s_time_t get_s_time(void)
{
u32 delta, low, pcc;
s_time_t now;
s_time_t incr;
/* read two values (pcc, now) "atomically" */
again:
pcc = stime_pcc;
now = stime_now;
if (stime_pcc != pcc) goto again;
/* only use bottom 32bits of TSC. This should be sufficient */
rdtscl(low);
delta = low - pcc;
incr = ((s_time_t)(stime_scale) * delta) >> 10;
return now + incr;
}
/* update time variables once in a while */
extern void update_time(void);
/*
* Domain Virtual Time
*/
typedef u64 dv_time_t;
#endif /* _ASM_TIME_H_ */
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