| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <fcntl.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| #include "msrtool.h" |
| |
| static int msr_fd[MAX_CORES] = {-1, -1, -1, -1, -1, -1, -1, -1}; |
| |
| int linux_probe(const struct sysdef *system) { |
| struct stat st; |
| return 0 == stat("/dev/cpu/0/msr", &st); |
| } |
| |
| int linux_open(uint8_t cpu, enum SysModes mode) { |
| int fmode; |
| char fn[32]; |
| switch (mode) { |
| case SYS_RDWR: |
| fmode = O_RDWR; |
| break; |
| case SYS_WRONLY: |
| fmode = O_WRONLY; |
| break; |
| case SYS_RDONLY: |
| default: |
| fmode = O_RDONLY; |
| break; |
| } |
| if (cpu >= MAX_CORES) { |
| fprintf(stderr, "%s: only cores 0-%d are supported. requested=%d\n", __func__, MAX_CORES, cpu); |
| return 0; |
| } |
| if (snprintf(fn, sizeof(fn), "/dev/cpu/%d/msr", cpu) == -1) { |
| fprintf(stderr, "%s: snprintf: %s\n", __func__, strerror(errno)); |
| return 0; |
| } |
| msr_fd[cpu] = open(fn, fmode); |
| if (-1 == msr_fd[cpu]) { |
| fprintf(stderr, "open(%s): %s\n", fn, strerror(errno)); |
| return 0; |
| } |
| return 1; |
| } |
| |
| int linux_close(uint8_t cpu) { |
| int ret; |
| if (cpu >= MAX_CORES) { |
| fprintf(stderr, "%s: only cores 0-%d are supported. requested=%d\n", __func__, MAX_CORES, cpu); |
| return 0; |
| } |
| ret = close(msr_fd[cpu]); |
| msr_fd[cpu] = 0; |
| return 0 == ret; |
| } |
| |
| int linux_rdmsr(uint8_t cpu, uint32_t addr, struct msr *val) { |
| struct msr tmp; |
| if (lseek(msr_fd[cpu], addr, SEEK_SET) == -1) { |
| SYSERROR(lseek, addr); |
| return 0; |
| } |
| if (read(msr_fd[cpu], &tmp, 8) != 8) { |
| SYSERROR(read, addr); |
| return 0; |
| } |
| val->hi = tmp.lo; |
| val->lo = tmp.hi; |
| return 1; |
| } |