LXR linux/tools/testing/selftests/intel

   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
  14int 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