Patrick Georgi | ac95903 | 2020-05-05 22:49:26 +0200 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
Peter Stuge | dad1e30 | 2008-11-22 17:13:36 +0000 | [diff] [blame] | 2 | |
| 3 | #include <sys/types.h> |
| 4 | #include <sys/stat.h> |
| 5 | #include <fcntl.h> |
| 6 | #include <unistd.h> |
| 7 | #include <string.h> |
| 8 | #include <errno.h> |
| 9 | |
| 10 | #include "msrtool.h" |
| 11 | |
| 12 | static int msr_fd[MAX_CORES] = {-1, -1, -1, -1, -1, -1, -1, -1}; |
| 13 | |
| 14 | int linux_probe(const struct sysdef *system) { |
| 15 | struct stat st; |
| 16 | return 0 == stat("/dev/cpu/0/msr", &st); |
| 17 | } |
| 18 | |
| 19 | int linux_open(uint8_t cpu, enum SysModes mode) { |
| 20 | int fmode; |
| 21 | char fn[32]; |
| 22 | switch (mode) { |
| 23 | case SYS_RDWR: |
| 24 | fmode = O_RDWR; |
| 25 | break; |
| 26 | case SYS_WRONLY: |
| 27 | fmode = O_WRONLY; |
| 28 | break; |
| 29 | case SYS_RDONLY: |
| 30 | default: |
| 31 | fmode = O_RDONLY; |
| 32 | break; |
| 33 | } |
| 34 | if (cpu >= MAX_CORES) { |
| 35 | fprintf(stderr, "%s: only cores 0-%d are supported. requested=%d\n", __func__, MAX_CORES, cpu); |
| 36 | return 0; |
| 37 | } |
| 38 | if (snprintf(fn, sizeof(fn), "/dev/cpu/%d/msr", cpu) == -1) { |
| 39 | fprintf(stderr, "%s: snprintf: %s\n", __func__, strerror(errno)); |
| 40 | return 0; |
| 41 | } |
| 42 | msr_fd[cpu] = open(fn, fmode); |
| 43 | if (-1 == msr_fd[cpu]) { |
| 44 | fprintf(stderr, "open(%s): %s\n", fn, strerror(errno)); |
| 45 | return 0; |
| 46 | } |
| 47 | return 1; |
| 48 | } |
| 49 | |
| 50 | int linux_close(uint8_t cpu) { |
| 51 | int ret; |
| 52 | if (cpu >= MAX_CORES) { |
| 53 | fprintf(stderr, "%s: only cores 0-%d are supported. requested=%d\n", __func__, MAX_CORES, cpu); |
| 54 | return 0; |
| 55 | } |
| 56 | ret = close(msr_fd[cpu]); |
| 57 | msr_fd[cpu] = 0; |
| 58 | return 0 == ret; |
| 59 | } |
| 60 | |
| 61 | int linux_rdmsr(uint8_t cpu, uint32_t addr, struct msr *val) { |
Peter Stuge | c1d6ed9 | 2009-01-26 17:03:05 +0000 | [diff] [blame] | 62 | struct msr tmp; |
Peter Stuge | dad1e30 | 2008-11-22 17:13:36 +0000 | [diff] [blame] | 63 | if (lseek(msr_fd[cpu], addr, SEEK_SET) == -1) { |
| 64 | SYSERROR(lseek, addr); |
| 65 | return 0; |
| 66 | } |
Peter Stuge | c1d6ed9 | 2009-01-26 17:03:05 +0000 | [diff] [blame] | 67 | if (read(msr_fd[cpu], &tmp, 8) != 8) { |
Peter Stuge | dad1e30 | 2008-11-22 17:13:36 +0000 | [diff] [blame] | 68 | SYSERROR(read, addr); |
| 69 | return 0; |
| 70 | } |
Peter Stuge | c1d6ed9 | 2009-01-26 17:03:05 +0000 | [diff] [blame] | 71 | val->hi = tmp.lo; |
| 72 | val->lo = tmp.hi; |
Peter Stuge | dad1e30 | 2008-11-22 17:13:36 +0000 | [diff] [blame] | 73 | return 1; |
| 74 | } |