// SPDX-License-Identifier: GPL-2.0 #include <math.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/timeb.h> #include <sched.h> #include <errno.h> int main(int argc, char **argv) { int cpu, fd; long long msr; char msr_file_name[64]; if (argc != 2) return 1; errno = 0; cpu = strtol(argv[1], (char **) NULL, 10); if (errno) return 1; sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu); fd = open(msr_file_name, O_RDONLY); if (fd == -1) { perror("Failed to open"); return 1; } pread(fd, &msr, sizeof(msr), 0x199); printf("msr 0x199: 0x%llx\n", msr); return 0; }