Patrick Georgi | afd4c87 | 2020-05-05 23:43:18 +0200 | [diff] [blame] | 1 | /* intelmetool */ |
Patrick Georgi | ac95903 | 2020-05-05 22:49:26 +0200 | [diff] [blame] | 2 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 3 | |
| 4 | #include <fcntl.h> |
| 5 | #include <unistd.h> |
| 6 | #include <stdio.h> |
| 7 | #include <stdlib.h> |
| 8 | #include <string.h> |
| 9 | #include <errno.h> |
| 10 | |
| 11 | #include "msr.h" |
| 12 | |
| 13 | #ifndef __DARWIN__ |
| 14 | static int fd_msr = 0; |
| 15 | |
Patrick Rudolph | 3df9dbe | 2017-11-25 14:43:06 +0100 | [diff] [blame] | 16 | static int rdmsr(int addr, uint64_t *msr) |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 17 | { |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 18 | if (lseek(fd_msr, (off_t) addr, SEEK_SET) == -1) { |
| 19 | perror("Could not lseek() to MSR"); |
| 20 | close(fd_msr); |
| 21 | return -1; |
| 22 | } |
| 23 | |
Patrick Rudolph | 3df9dbe | 2017-11-25 14:43:06 +0100 | [diff] [blame] | 24 | if (read(fd_msr, msr, 8) == 8) { |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 25 | close(fd_msr); |
Patrick Rudolph | 3df9dbe | 2017-11-25 14:43:06 +0100 | [diff] [blame] | 26 | return 0; |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 27 | } |
| 28 | |
| 29 | if (errno == EIO) { |
| 30 | perror("IO error couldn't read MSR."); |
| 31 | close(fd_msr); |
Patrick Rudolph | 3df9dbe | 2017-11-25 14:43:06 +0100 | [diff] [blame] | 32 | /* On older platforms the MSR might not exists */ |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 33 | return -2; |
| 34 | } |
| 35 | |
| 36 | perror("Couldn't read() MSR"); |
| 37 | close(fd_msr); |
| 38 | return -1; |
| 39 | } |
| 40 | #endif |
| 41 | |
Pablo Stebler | 9ac91d2 | 2020-09-18 10:32:22 +0200 | [diff] [blame] | 42 | int msr_bootguard(uint64_t *msr) |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 43 | { |
| 44 | |
| 45 | #ifndef __DARWIN__ |
| 46 | fd_msr = open("/dev/cpu/0/msr", O_RDONLY); |
| 47 | if (fd_msr < 0) { |
| 48 | perror("Error while opening /dev/cpu/0/msr"); |
| 49 | printf("Did you run 'modprobe msr'?\n"); |
| 50 | return -1; |
| 51 | } |
| 52 | |
Patrick Rudolph | 3df9dbe | 2017-11-25 14:43:06 +0100 | [diff] [blame] | 53 | if (rdmsr(MSR_BOOTGUARD, msr) < 0) |
| 54 | return -1; |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 55 | #endif |
| 56 | |
Philipp Deppenwiese | 73add17 | 2016-08-26 02:10:51 +0200 | [diff] [blame] | 57 | return 0; |
| 58 | } |