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Diffstat (limited to '')
-rw-r--r-- | include/grub/i386/rdmsr.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/grub/i386/rdmsr.h b/include/grub/i386/rdmsr.h new file mode 100644 index 0000000..c0a0c71 --- /dev/null +++ b/include/grub/i386/rdmsr.h @@ -0,0 +1,37 @@ +/* + * 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_RDMSR_H +#define GRUB_RDMSR_H 1 + +/* + * TODO: Add a general protection exception handler. + * Accessing a reserved or unimplemented MSR address results in a GP#. + */ + +static inline grub_uint64_t +grub_msr_read (grub_uint32_t msr_id) +{ + grub_uint32_t low, high; + + asm volatile ("rdmsr" : "=a" (low), "=d" (high) : "c" (msr_id)); + + return ((grub_uint64_t)high << 32) | low; +} + +#endif /* GRUB_RDMSR_H */ |