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sortix--sortix/libc/include/msr.h
Jonas 'Sortie' Termansen af23f7ad5e Add rdmsr(2) and wrmsr(2).
2014-05-29 17:14:30 +02:00

97 lines
2.6 KiB
C

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
This file is part of the Sortix C Library.
The Sortix C Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
The Sortix C Library 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
msr.h
High-level access to the rdmsr and wrmsr instructions for accessing and
modifying machine specific registers.
*******************************************************************************/
#ifndef INCLUDE_MSR_H
#define INCLUDE_MSR_H
#include <sys/cdefs.h>
#include <stdint.h>
#if defined(__i386__) || defined(__x86_64__)
__BEGIN_DECLS
#define MSRID_FSBASE __UINT32_C(0xC0000100)
#define MSRID_GSBASE __UINT32_C(0xC0000101)
__attribute__((unused))
static __inline uint64_t rdmsr_instruction(uint32_t msrid)
{
uint32_t low;
uint32_t high;
__asm__ __volatile__ ("rdmsr" : "=a"(low), "=d"(high) : "c"(msrid));
return (uint64_t) low << 0 | (uint64_t) high << 32;
}
__attribute__((unused))
static __inline uint64_t wrmsr_instruction(uint32_t msrid, uint64_t value)
{
uint32_t low = value >> 0 & 0xFFFFFFFF;
uint32_t high = value >> 32 & 0xFFFFFFFF;;
__asm__ __volatile__ ("wrmsr" : : "a"(low), "d"(high), "c"(msrid) : "memory");
return value;
}
#if __STDC_HOSTED__
uint64_t rdmsr(uint32_t msrid);
uint64_t wrmsr(uint32_t msrid, uint64_t value);
#else
__attribute__((unused))
static __inline uint64_t rdmsr(uint32_t msrid)
{
return rdmsr_instruction(msrid);
}
__attribute__((unused))
static __inline uint64_t wrmsr(uint32_t msrid, uint64_t value)
{
return wrmsr_instruction(msrid, value);
}
#endif
__attribute__((unused))
static __inline void rdmsr_split(uint32_t msrid, uint32_t* low, uint32_t* high)
{
uint64_t result = rdmsr(msrid);
*low = result >> 0 & 0xFFFFFFFF;
*high = result >> 32 & 0xFFFFFFFF;
}
__attribute__((unused))
static __inline void wrmsr_split(uint32_t msrid, uint32_t low, uint32_t high)
{
wrmsr(msrid, (uint64_t) low << 0 | (uint64_t) high << 32);
}
__END_DECLS
#endif
#endif