59 lines
995 B
C
59 lines
995 B
C
/* intelmetool */
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/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "msr.h"
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#ifndef __DARWIN__
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static int fd_msr = 0;
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static int rdmsr(int addr, uint64_t *msr)
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{
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if (lseek(fd_msr, (off_t) addr, SEEK_SET) == -1) {
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perror("Could not lseek() to MSR");
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close(fd_msr);
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return -1;
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}
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if (read(fd_msr, msr, 8) == 8) {
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close(fd_msr);
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return 0;
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}
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if (errno == EIO) {
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perror("IO error couldn't read MSR.");
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close(fd_msr);
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/* On older platforms the MSR might not exists */
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return -2;
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}
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perror("Couldn't read() MSR");
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close(fd_msr);
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return -1;
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}
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#endif
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int msr_bootguard(uint64_t *msr)
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{
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#ifndef __DARWIN__
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fd_msr = open("/dev/cpu/0/msr", O_RDONLY);
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if (fd_msr < 0) {
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perror("Error while opening /dev/cpu/0/msr");
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printf("Did you run 'modprobe msr'?\n");
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return -1;
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}
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if (rdmsr(MSR_BOOTGUARD, msr) < 0)
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return -1;
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#endif
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return 0;
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}
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