diff options
Diffstat (limited to 'util/intelmetool/msr.c')
-rw-r--r-- | util/intelmetool/msr.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/util/intelmetool/msr.c b/util/intelmetool/msr.c new file mode 100644 index 0000000000..1010c0e324 --- /dev/null +++ b/util/intelmetool/msr.c @@ -0,0 +1,78 @@ +/* intelmetool + * + * Copyright (C) 2013-2016 Philipp Deppenwiese <zaolin@das-labor.org>, + * Copyright (C) 2013-2016 Alexander Couzens <lynxis@fe80.eu> + * + * This program 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 2 of + * the License, or any later version. + * + * This program 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. + */ + +#include <fcntl.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +#include "msr.h" + +#ifndef __DARWIN__ +static int fd_msr = 0; + +static uint64_t rdmsr(int addr) +{ + uint32_t buf[2]; + uint64_t msr = 0; + + if (lseek(fd_msr, (off_t) addr, SEEK_SET) == -1) { + perror("Could not lseek() to MSR"); + close(fd_msr); + return -1; + } + + if (read(fd_msr, buf, 8) == 8) { + msr = buf[1]; + msr <<= 32; + msr |= buf[0]; + close(fd_msr); + return msr; + } + + if (errno == EIO) { + perror("IO error couldn't read MSR."); + close(fd_msr); + return -2; + } + + perror("Couldn't read() MSR"); + close(fd_msr); + return -1; +} +#endif + +int msr_bootguard(uint64_t *msr, int debug) +{ + +#ifndef __DARWIN__ + fd_msr = open("/dev/cpu/0/msr", O_RDONLY); + if (fd_msr < 0) { + perror("Error while opening /dev/cpu/0/msr"); + printf("Did you run 'modprobe msr'?\n"); + return -1; + } + + *msr = rdmsr(MSR_BOOTGUARD); +#endif + + if (!debug) + *msr &= ~0xff; + + return 0; +} |