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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2008,2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef KERNEL_CPU_TSC_HEADER
#define KERNEL_CPU_TSC_HEADER 1
#include <grub/types.h>
#include <grub/i386/cpuid.h>
void grub_tsc_init (void);
/* In ms per 2^32 ticks. */
extern grub_uint32_t EXPORT_VAR(grub_tsc_rate);
int
grub_tsc_calibrate_from_xen (void);
int
grub_tsc_calibrate_from_efi (void);
int
grub_tsc_calibrate_from_pmtimer (void);
int
grub_tsc_calibrate_from_pit (void);
/* Read the TSC value, which increments with each CPU clock cycle. */
static __inline grub_uint64_t
grub_get_tsc (void)
{
grub_uint32_t lo, hi;
grub_uint32_t a,b,c,d;
/* The CPUID instruction is a 'serializing' instruction, and
avoids out-of-order execution of the RDTSC instruction. */
grub_cpuid (0,a,b,c,d);
/* Read TSC value. We cannot use "=A", since this would use
%rax on x86_64. */
asm volatile ("rdtsc":"=a" (lo), "=d" (hi));
return (((grub_uint64_t) hi) << 32) | lo;
}
static __inline int
grub_cpu_is_tsc_supported (void)
{
#if !defined(GRUB_MACHINE_XEN) && !defined(GRUB_MACHINE_XEN_PVH)
grub_uint32_t a,b,c,d;
if (! grub_cpu_is_cpuid_supported ())
return 0;
grub_cpuid(1,a,b,c,d);
return (d & (1 << 4)) != 0;
#else
return 1;
#endif
}
#endif /* ! KERNEL_CPU_TSC_HEADER */
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