tools/testing/selftests/intel_pstate/msr.c

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