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/*
* This file is part of the flashrom project.
*
* Copyright (C) 2009 Peter Stuge <peter@stuge.se>
* Copyright (C) 2009 coresystems GmbH
* Copyright (C) 2010 Carl-Daniel Hailfinger
* Copyright (C) 2010 Rudolf Marek <r.marek@assembler.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/* MSR abstraction implementations for Linux, OpenBSD, FreeBSD/Dragonfly, OSX, libpayload
* and a non-working default implementation on the bottom. See also hwaccess.h for some (re)declarations.
*/
#include "hwaccess_x86_msr.h"
#include "flash.h"
#ifdef __linux__
/*
* Reading and writing to MSRs, however requires instructions rdmsr/wrmsr,
* which are ring0 privileged instructions so only the kernel can do the
* read/write. This function, therefore, requires that the msr kernel module
* be loaded to access these instructions from user space using device
* /dev/cpu/0/msr.
*/
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
static int fd_msr = -1;
msr_t rdmsr(int addr)
{
uint32_t buf[2];
msr_t msr = { 0xffffffff, 0xffffffff };
if (lseek(fd_msr, (off_t) addr, SEEK_SET) == -1) {
msg_perr("Could not lseek() MSR: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
if (read(fd_msr, buf, 8) == 8) {
msr.lo = buf[0];
msr.hi = buf[1];
return msr;
}
if (errno != EIO) {
// A severe error.
msg_perr("Could not read() MSR: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
return msr;
}
int wrmsr(int addr, msr_t msr)
{
uint32_t buf[2];
buf[0] = msr.lo;
buf[1] = msr.hi;
if (lseek(fd_msr, (off_t) addr, SEEK_SET) == -1) {
msg_perr("Could not lseek() MSR: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
if (write(fd_msr, buf, 8) != 8 && errno != EIO) {
msg_perr("Could not write() MSR: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
/* Some MSRs must not be written. */
if (errno == EIO)
return -1;
return 0;
}
int setup_cpu_msr(int cpu)
{
char msrfilename[64] = { 0 };
snprintf(msrfilename, sizeof(msrfilename), "/dev/cpu/%d/msr", cpu);
if (fd_msr != -1) {
msg_pinfo("MSR was already initialized\n");
return -1;
}
fd_msr = open(msrfilename, O_RDWR);
if (fd_msr < 0) {
msg_perr("Error while opening %s: %s\n", msrfilename, strerror(errno));
msg_pinfo("Did you run 'modprobe msr'?\n");
return -1;
}
return 0;
}
void cleanup_cpu_msr(void)
{
if (fd_msr == -1) {
msg_pinfo("No MSR initialized.\n");
return;
}
close(fd_msr);
/* Clear MSR file descriptor. */
fd_msr = -1;
}
#elif defined(__OpenBSD__) && defined (__i386__) /* This does only work for certain AMD Geode LX systems see amdmsr(4). */
#include <stdint.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <machine/amdmsr.h>
static int fd_msr = -1;
msr_t rdmsr(int addr)
{
struct amdmsr_req args;
msr_t msr = { 0xffffffff, 0xffffffff };
args.addr = (uint32_t)addr;
if (ioctl(fd_msr, RDMSR, &args) < 0) {
msg_perr("Error while executing RDMSR ioctl: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
msr.lo = args.val & 0xffffffff;
msr.hi = args.val >> 32;
return msr;
}
int wrmsr(int addr, msr_t msr)
{
struct amdmsr_req args;
args.addr = addr;
args.val = (((uint64_t)msr.hi) << 32) | msr.lo;
if (ioctl(fd_msr, WRMSR, &args) < 0) {
msg_perr("Error while executing WRMSR ioctl: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
return 0;
}
int setup_cpu_msr(int cpu)
{
char msrfilename[64] = { 0 };
snprintf(msrfilename, sizeof(msrfilename), "/dev/amdmsr");
if (fd_msr != -1) {
msg_pinfo("MSR was already initialized\n");
return -1;
}
fd_msr = open(msrfilename, O_RDWR);
if (fd_msr < 0) {
msg_perr("Error while opening %s: %s\n", msrfilename, strerror(errno));
return -1;
}
return 0;
}
void cleanup_cpu_msr(void)
{
if (fd_msr == -1) {
msg_pinfo("No MSR initialized.\n");
return;
}
close(fd_msr);
/* Clear MSR file descriptor. */
fd_msr = -1;
}
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
typedef struct {
int msr;
uint64_t data;
} cpu_msr_args_t;
#define CPU_RDMSR _IOWR('c', 1, cpu_msr_args_t)
#define CPU_WRMSR _IOWR('c', 2, cpu_msr_args_t)
static int fd_msr = -1;
msr_t rdmsr(int addr)
{
cpu_msr_args_t args;
msr_t msr = { 0xffffffff, 0xffffffff };
args.msr = addr;
if (ioctl(fd_msr, CPU_RDMSR, &args) < 0) {
msg_perr("Error while executing CPU_RDMSR ioctl: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
msr.lo = args.data & 0xffffffff;
msr.hi = args.data >> 32;
return msr;
}
int wrmsr(int addr, msr_t msr)
{
cpu_msr_args_t args;
args.msr = addr;
args.data = (((uint64_t)msr.hi) << 32) | msr.lo;
if (ioctl(fd_msr, CPU_WRMSR, &args) < 0) {
msg_perr("Error while executing CPU_WRMSR ioctl: %s\n", strerror(errno));
close(fd_msr);
exit(1);
}
return 0;
}
int setup_cpu_msr(int cpu)
{
char msrfilename[64] = { 0 };
snprintf(msrfilename, sizeof(msrfilename), "/dev/cpu%d", cpu);
if (fd_msr != -1) {
msg_pinfo("MSR was already initialized\n");
return -1;
}
fd_msr = open(msrfilename, O_RDWR);
if (fd_msr < 0) {
msg_perr("Error while opening %s: %s\n", msrfilename, strerror(errno));
msg_pinfo("Did you install ports/sysutils/devcpu?\n");
return -1;
}
return 0;
}
void cleanup_cpu_msr(void)
{
if (fd_msr == -1) {
msg_pinfo("No MSR initialized.\n");
return;
}
close(fd_msr);
/* Clear MSR file descriptor. */
fd_msr = -1;
}
#elif defined(__MACH__) && defined(__APPLE__)
/* rdmsr() and wrmsr() are provided by DirectHW which needs neither setup nor cleanup. */
int setup_cpu_msr(int cpu)
{
// Always succeed for now
return 0;
}
void cleanup_cpu_msr(void)
{
// Nothing, yet.
}
#elif defined(__LIBPAYLOAD__)
msr_t libpayload_rdmsr(int addr)
{
msr_t msr;
unsigned long long val = _rdmsr(addr);
msr.lo = val & 0xffffffff;
msr.hi = val >> 32;
return msr;
}
int libpayload_wrmsr(int addr, msr_t msr)
{
_wrmsr(addr, msr.lo | ((unsigned long long)msr.hi << 32));
return 0;
}
int setup_cpu_msr(int cpu)
{
return 0;
}
void cleanup_cpu_msr(void)
{
}
#else
/* default MSR implementation */
msr_t rdmsr(int addr)
{
msr_t ret = { 0xffffffff, 0xffffffff };
return ret;
}
int wrmsr(int addr, msr_t msr)
{
return -1;
}
int setup_cpu_msr(int cpu)
{
msg_pinfo("No MSR support for your OS yet.\n");
return -1;
}
void cleanup_cpu_msr(void)
{
// Nothing, yet.
}
#endif // OS switches for MSR code