grub/include/grub/i386/wrmsr.h

35 lines
1.1 KiB
C

/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2019 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 GRUB_WRMSR_H
#define GRUB_WRMSR_H 1
/*
* TODO: Add a general protection exception handler.
* Accessing a reserved or unimplemented MSR address results in a GP#.
*/
extern inline void grub_msr_write(grub_uint32_t msr_id, grub_uint64_t msr_value)
{
grub_uint32_t low = msr_value, high = msr_value >> 32;
asm volatile ("wrmsr" : : "c" (msr_id), "a" (low), "d" (high));
}
#endif /* GRUB_WRMSR_H */