1 // SPDX-License-Identifier: GPL-2.0
2 #include <math.h>
3 #include <unistd.h>
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 #include <sys/timeb.h>
10 #include <sched.h>
11 #include <errno.h>
12 
13 
14 int main(int argc, char **argv) {
15 	int cpu, fd;
16 	long long msr;
17 	char msr_file_name[64];
18 
19 	if (argc != 2)
20 		return 1;
21 
22 	errno = 0;
23 	cpu = strtol(argv[1], (char **) NULL, 10);
24 
25 	if (errno)
26 		return 1;
27 
28 	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
29 	fd = open(msr_file_name, O_RDONLY);
30 
31 	if (fd == -1) {
32 		perror("Failed to open");
33 		return 1;
34 	}
35 
36 	pread(fd, &msr,  sizeof(msr), 0x199);
37 
38 	printf("msr 0x199: 0x%llx\n", msr);
39 	return 0;
40 }
41