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