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/* 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;
}
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