1 files changed, 382 insertions, 0 deletions
diff --git a/hwaccess_x86_msr.c b/hwaccess_x86_msr.c
new file mode 100644
index 000000000..98e51d441
--- /dev/null
+++ b/hwaccess_x86_msr.c
@@ -0,0 +1,382 @@
+/*
+ * 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.
+ */
+
+#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 msr_read(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 msr_write(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 msr_setup(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 msr_cleanup(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 <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <machine/amdmsr.h>
+
+static int fd_msr = -1;
+
+msr_t msr_read(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 msr_write(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 msr_setup(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 msr_cleanup(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 msr_read(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 msr_write(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 msr_setup(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 msr_cleanup(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__)
+/*
+ * DirectHW has identical, but conflicting typedef for msr_t. We redefine msr_t
+ * to directhw_msr_t for DirectHW.
+ * rdmsr() and wrmsr() are provided by DirectHW and need neither setup nor cleanup.
+ */
+#define msr_t directhw_msr_t
+#include <DirectHW/DirectHW.h>
+#undef msr_t
+
+msr_t msr_read(int addr)
+{
+	directhw_msr_t msr;
+	msr = rdmsr(addr);
+	return (msr_t){msr.hi, msr.lo};
+}
+
+int msr_write(int addr, msr_t msr)
+{
+	return wrmsr(addr, (directhw_msr_t){msr.hi, msr.lo});
+}
+
+int msr_setup(int cpu)
+{
+	// Always succeed for now
+	return 0;
+}
+
+void msr_cleanup(void)
+{
+	// Nothing, yet.
+}
+#elif defined(__LIBPAYLOAD__)
+#include <arch/msr.h>
+
+msr_t msr_read(int addr)
+{
+	msr_t msr;
+	unsigned long long val = _rdmsr(addr);
+	msr.lo = val & 0xffffffff;
+	msr.hi = val >> 32;
+	return msr;
+}
+
+int msr_write(int addr, msr_t msr)
+{
+	_wrmsr(addr, msr.lo | ((unsigned long long)msr.hi << 32));
+	return 0;
+}
+
+int msr_setup(int cpu)
+{
+	return 0;
+}
+
+void msr_cleanup(void)
+{
+}
+#else
+/* default MSR implementation */
+msr_t msr_read(int addr)
+{
+	msr_t ret = { 0xffffffff, 0xffffffff };
+
+	return ret;
+}
+
+int msr_write(int addr, msr_t msr)
+{
+	return -1;
+}
+
+int msr_setup(int cpu)
+{
+	msg_pinfo("No MSR support for your OS yet.\n");
+	return -1;
+}
+
+void msr_cleanup(void)
+{
+	// Nothing, yet.
+}
+#endif // OS switches for MSR code