- Add cpuctl(4) pseudo-device driver to provide access to some low-level

  features of CPUs like reading/writing machine-specific registers,
  retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
  the features of cpuctl(4).
- Add subsequent manpages.

The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.

The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.

The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.

Currently only Intel and AMD cpus are supported and were tested.

Approved by:	kib
Reviewed by:	rpaulo, cokane, Peter Jeremy
MFC after:	1 month

1 files changed, 362 insertions, 0 deletions

diff --git a/usr.sbin/cpucontrol/cpucontrol.c b/usr.sbin/cpucontrol/cpucontrol.c
new file mode 100644
index 0000000..4736e23
--- /dev/null
+++ b/usr.sbin/cpucontrol/cpucontrol.c
@@ -0,0 +1,362 @@
+/*-
+ * Copyright (c) 2008 Stanislav Sedov <stas@FreeBSD.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This utility provides userland access to the cpuctl(4) pseudo-device
+ * features.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <err.h>
+#include <sysexits.h>
+#include <dirent.h>
+
+#include <sys/queue.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/cpuctl.h>
+
+#include "cpucontrol.h"
+#include "amd.h"
+#include "intel.h"
+
+int	verbosity_level = 0;
+
+#define	DEFAULT_DATADIR	"/usr/local/share/cpucontrol"
+
+#define	FLAG_I	0x01
+#define	FLAG_M	0x02
+#define	FLAG_U	0x04
+
+#define	HIGH(val)	(uint32_t)(((val) >> 32) & 0xffffffff)
+#define	LOW(val)	(uint32_t)((val) & 0xffffffff)
+
+/*
+ * Macros for freeing SLISTs, probably must be in /sys/queue.h
+ */
+#define	SLIST_FREE(head, field, freef) do {				\
+		typeof(SLIST_FIRST(head)) __elm0;			\
+		typeof(SLIST_FIRST(head)) __elm;			\
+		SLIST_FOREACH_SAFE(__elm, (head), field, __elm0)	\
+			(void)(freef)(__elm);				\
+} while(0);
+
+struct datadir {
+	const char		*path;
+	SLIST_ENTRY(datadir)	next;
+};
+static SLIST_HEAD(, datadir) datadirs = SLIST_HEAD_INITIALIZER(&datadirs);
+
+struct ucode_handler {
+	ucode_probe_t *probe;
+	ucode_update_t *update;
+} handlers[] = {
+	{ intel_probe, intel_update },
+	{ amd_probe, amd_update },
+};
+#define NHANDLERS (sizeof(handlers) / sizeof(*handlers))
+
+static void	usage(void);
+static int	isdir(const char *path);
+static int	do_cpuid(const char *cmdarg, const char *dev);
+static int	do_msr(const char *cmdarg, const char *dev);
+static int	do_update(const char *dev);
+static void	datadir_add(const char *path);
+
+static void __dead2
+usage()
+{
+	const char *name;
+
+	name = getprogname();
+	if (name == NULL)
+		name = "cpuctl";
+	fprintf(stderr, "Usage: %s [-vh] [-d datadir] [-m msr[=value] | "
+	    "-i level | -u] device\n", name);
+	exit(EX_USAGE);
+}
+
+static int
+isdir(const char *path)
+{
+	int error;
+	struct stat st;
+
+	error = stat(path, &st);
+	if (error < 0) {
+		WARN(0, "stat(%s)", path);
+		return (error);
+	}
+	return (st.st_mode & S_IFDIR);
+}
+
+static int
+do_cpuid(const char *cmdarg, const char *dev)
+{
+	unsigned int level;
+	cpuctl_cpuid_args_t args;
+	int fd, error;
+	char *endptr;
+
+	assert(cmdarg != NULL);
+	assert(dev != NULL);
+
+	level = strtoul(cmdarg, &endptr, 16);
+	if (*cmdarg == '\0' || *endptr != '\0') {
+		WARNX(0, "incorrect operand: %s", cmdarg);
+		usage();
+		/* NOTREACHED */
+	}
+
+	/*
+	 * Fill ioctl argument structure.
+	 */
+	args.level = level;
+	fd = open(dev, O_RDONLY);
+	if (fd < 0) {
+		WARNX(0, "error opening %s for reading", dev);
+		return (1);
+	}
+	error = ioctl(fd, CPUCTL_CPUID, &args);
+	if (error < 0) {
+		WARNX(0, "ioctl(%s, CPUCTL_CPUID)", dev);
+		close(fd);
+		return (error);
+	}
+	fprintf(stdout, "cpuid level 0x%x: 0x%.8x 0x%.8x 0x%.8x 0x%.8x\n",
+	    level, args.data[0], args.data[1], args.data[2], args.data[3]);
+	close(fd);
+	return (0);
+}
+
+static int
+do_msr(const char *cmdarg, const char *dev)
+{
+	unsigned int msr;
+	cpuctl_msr_args_t args;
+	int fd, error;
+	int wr = 0;
+	char *p;
+	char *endptr;
+
+	assert(cmdarg != NULL);
+	assert(dev != NULL);
+
+	p = strchr(cmdarg, '=');
+	if (p != NULL) {
+		wr = 1;
+		*p++ = '\0';
+		args.data = strtoull(p, &endptr, 16);
+		if (*p == '\0' || *endptr != '\0') {
+			WARNX(0, "incorrect MSR value: %s", p);
+			usage();
+			/* NOTREACHED */
+		}
+	}
+	msr = strtoul(cmdarg, &endptr, 16);
+	if (*cmdarg == '\0' || *endptr != '\0') {
+		WARNX(0, "incorrect MSR register: %s", cmdarg);
+		usage();
+		/* NOTREACHED */
+	}
+
+	/*
+	 * Fill ioctl argument structure.
+	 */
+	args.msr = msr;
+	fd = open(dev, wr == 0 ? O_RDONLY : O_WRONLY);
+	if (fd < 0) {
+		WARNX(0, "error opening %s for %s", dev,
+		    wr == 0 ? "reading" : "writing");
+		return (1);
+	}
+	error = ioctl(fd, wr == 0 ? CPUCTL_RDMSR : CPUCTL_WRMSR, &args);
+	if (error < 0) {
+		WARNX(0, "ioctl(%s, %s)", dev,
+		    wr == 0 ? "CPUCTL_RDMSR" : "CPUCTL_WRMSR");
+		close(fd);
+		return (1);
+	}
+	if (wr == 0)
+		fprintf(stdout, "MSR 0x%x: 0x%.8x 0x%.8x\n", msr,
+		    HIGH(args.data), LOW(args.data));
+	close(fd);
+	return (0);
+}
+
+static int
+do_update(const char *dev)
+{
+	int fd;
+	unsigned int i;
+	int error;
+	struct ucode_handler *handler;
+	struct datadir *dir;
+	DIR *dirfd;
+	struct dirent *direntry;
+	char buf[MAXPATHLEN];
+
+	fd = open(dev, O_RDONLY);
+	if (fd < 0) {
+		WARNX(0, "error opening %s for reading", dev);
+		return (1);
+	}
+
+	/*
+	 * Find the appropriate handler for device.
+	 */
+	for (i = 0; i < NHANDLERS; i++)
+		if (handlers[i].probe(fd) == 0)
+			break;
+	if (i < NHANDLERS)
+		handler = &handlers[i];
+	else {
+		WARNX(0, "cannot find the appropriate handler for device");
+		close(fd);
+		return (1);
+	}
+	close(fd);
+
+	/*
+	 * Process every image in specified data directories.
+	 */
+	SLIST_FOREACH(dir, &datadirs, next) {
+		dirfd  = opendir(dir->path);
+		if (dirfd == NULL) {
+			WARNX(1, "skipping directory %s: not accessible", dir->path);
+			continue;
+		}
+		while ((direntry = readdir(dirfd)) != NULL) {
+			if (direntry->d_namlen == 0)
+				continue;
+			error = snprintf(buf, sizeof(buf), "%s/%s", dir->path,
+			    direntry->d_name);
+			if ((unsigned)error >= sizeof(buf))
+				WARNX(0, "skipping %s, buffer too short",
+				    direntry->d_name);
+			if (isdir(buf) != 0) {
+				WARNX(2, "skipping %s: is a directory", buf);
+				continue;
+			}
+			handler->update(dev, buf);
+		}
+		error = closedir(dirfd);
+		if (error != 0)
+			WARN(0, "closedir(%s)", dir->path);
+	}
+	return (0);
+}
+
+/*
+ * Add new data directory to the search list.
+ */
+static void
+datadir_add(const char *path)
+{
+	struct datadir *newdir;
+
+	newdir = (struct datadir *)malloc(sizeof(*newdir));
+	if (newdir == NULL)
+		err(EX_OSERR, "cannot allocate memory");
+	newdir->path = path;
+	SLIST_INSERT_HEAD(&datadirs, newdir, next);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int c, flags;
+	const char *cmdarg;
+	const char *dev;
+	int error;
+
+	flags = 0;
+	error = 0;
+	cmdarg = "";	/* To keep gcc3 happy. */
+
+	/*
+	 * Add all default data dirs to the list first.
+	 */
+	datadir_add(DEFAULT_DATADIR);
+	while ((c = getopt(argc, argv, "d:hi:m:uv")) != -1) {
+		switch (c) {
+		case 'd':
+			datadir_add(optarg);
+			break;
+		case 'i':
+			flags |= FLAG_I;
+			cmdarg = optarg;
+			break;
+		case 'm':
+			flags |= FLAG_M;
+			cmdarg = optarg;
+			break;
+		case 'u':
+			flags |= FLAG_U;
+			break;
+		case 'v':
+			verbosity_level++;
+			break;
+		case 'h':
+			/* FALLTHROUGH */
+		default:
+			usage();
+			/* NOTREACHED */
+		}
+	}
+	argc -= optind;
+	argv += optind;
+	if (argc < 1) {
+		usage();
+		/* NOTREACHED */
+	}
+	dev = argv[0];
+	c = flags & (FLAG_I | FLAG_M | FLAG_U);
+	switch (c) {
+		case FLAG_I:
+			error = do_cpuid(cmdarg, dev);
+			break;
+		case FLAG_M:
+			error = do_msr(cmdarg, dev);
+			break;
+		case FLAG_U:
+			error = do_update(dev);
+			break;
+		default:
+			usage();	/* Only one command can be selected. */
+	}
+	SLIST_FREE(&datadirs, next, free);
+	return (error);
+}