Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1352 insertions, 0 deletions

diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
new file mode 100644
index 000000000..883b4a341
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -0,0 +1,1352 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ipmi_watchdog.c
+ *
+ * A watchdog timer based upon the IPMI interface.
+ *
+ * Author: MontaVista Software, Inc.
+ *         Corey Minyard <minyard@mvista.com>
+ *         source@mvista.com
+ *
+ * Copyright 2002 MontaVista Software Inc.
+ */
+
+#define pr_fmt(fmt) "IPMI Watchdog: " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ipmi.h>
+#include <linux/ipmi_smi.h>
+#include <linux/mutex.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/kdebug.h>
+#include <linux/rwsem.h>
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+#include <linux/notifier.h>
+#include <linux/nmi.h>
+#include <linux/reboot.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/atomic.h>
+#include <linux/sched/signal.h>
+
+#ifdef CONFIG_X86
+/*
+ * This is ugly, but I've determined that x86 is the only architecture
+ * that can reasonably support the IPMI NMI watchdog timeout at this
+ * time.  If another architecture adds this capability somehow, it
+ * will have to be a somewhat different mechanism and I have no idea
+ * how it will work.  So in the unlikely event that another
+ * architecture supports this, we can figure out a good generic
+ * mechanism for it at that time.
+ */
+#include <asm/kdebug.h>
+#include <asm/nmi.h>
+#define HAVE_DIE_NMI
+#endif
+
+/*
+ * The IPMI command/response information for the watchdog timer.
+ */
+
+/* values for byte 1 of the set command, byte 2 of the get response. */
+#define WDOG_DONT_LOG		(1 << 7)
+#define WDOG_DONT_STOP_ON_SET	(1 << 6)
+#define WDOG_SET_TIMER_USE(byte, use) \
+	byte = ((byte) & 0xf8) | ((use) & 0x7)
+#define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
+#define WDOG_TIMER_USE_BIOS_FRB2	1
+#define WDOG_TIMER_USE_BIOS_POST	2
+#define WDOG_TIMER_USE_OS_LOAD		3
+#define WDOG_TIMER_USE_SMS_OS		4
+#define WDOG_TIMER_USE_OEM		5
+
+/* values for byte 2 of the set command, byte 3 of the get response. */
+#define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
+	byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
+#define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
+#define WDOG_PRETIMEOUT_NONE		0
+#define WDOG_PRETIMEOUT_SMI		1
+#define WDOG_PRETIMEOUT_NMI		2
+#define WDOG_PRETIMEOUT_MSG_INT		3
+
+/* Operations that can be performed on a pretimout. */
+#define WDOG_PREOP_NONE		0
+#define WDOG_PREOP_PANIC	1
+/* Cause data to be available to read.  Doesn't work in NMI mode. */
+#define WDOG_PREOP_GIVE_DATA	2
+
+/* Actions to perform on a full timeout. */
+#define WDOG_SET_TIMEOUT_ACT(byte, use) \
+	byte = ((byte) & 0xf8) | ((use) & 0x7)
+#define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
+#define WDOG_TIMEOUT_NONE		0
+#define WDOG_TIMEOUT_RESET		1
+#define WDOG_TIMEOUT_POWER_DOWN		2
+#define WDOG_TIMEOUT_POWER_CYCLE	3
+
+/*
+ * Byte 3 of the get command, byte 4 of the get response is the
+ * pre-timeout in seconds.
+ */
+
+/* Bits for setting byte 4 of the set command, byte 5 of the get response. */
+#define WDOG_EXPIRE_CLEAR_BIOS_FRB2	(1 << 1)
+#define WDOG_EXPIRE_CLEAR_BIOS_POST	(1 << 2)
+#define WDOG_EXPIRE_CLEAR_OS_LOAD	(1 << 3)
+#define WDOG_EXPIRE_CLEAR_SMS_OS	(1 << 4)
+#define WDOG_EXPIRE_CLEAR_OEM		(1 << 5)
+
+/*
+ * Setting/getting the watchdog timer value.  This is for bytes 5 and
+ * 6 (the timeout time) of the set command, and bytes 6 and 7 (the
+ * timeout time) and 8 and 9 (the current countdown value) of the
+ * response.  The timeout value is given in seconds (in the command it
+ * is 100ms intervals).
+ */
+#define WDOG_SET_TIMEOUT(byte1, byte2, val) \
+	(byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
+#define WDOG_GET_TIMEOUT(byte1, byte2) \
+	(((byte1) | ((byte2) << 8)) / 10)
+
+#define IPMI_WDOG_RESET_TIMER		0x22
+#define IPMI_WDOG_SET_TIMER		0x24
+#define IPMI_WDOG_GET_TIMER		0x25
+
+#define IPMI_WDOG_TIMER_NOT_INIT_RESP	0x80
+
+static DEFINE_MUTEX(ipmi_watchdog_mutex);
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+static struct ipmi_user *watchdog_user;
+static int watchdog_ifnum;
+
+/* Default the timeout to 10 seconds. */
+static int timeout = 10;
+
+/* The pre-timeout is disabled by default. */
+static int pretimeout;
+
+/* Default timeout to set on panic */
+static int panic_wdt_timeout = 255;
+
+/* Default action is to reset the board on a timeout. */
+static unsigned char action_val = WDOG_TIMEOUT_RESET;
+
+static char action[16] = "reset";
+
+static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
+
+static char preaction[16] = "pre_none";
+
+static unsigned char preop_val = WDOG_PREOP_NONE;
+
+static char preop[16] = "preop_none";
+static DEFINE_SPINLOCK(ipmi_read_lock);
+static char data_to_read;
+static DECLARE_WAIT_QUEUE_HEAD(read_q);
+static struct fasync_struct *fasync_q;
+static atomic_t pretimeout_since_last_heartbeat;
+static char expect_close;
+
+static int ifnum_to_use = -1;
+
+/* Parameters to ipmi_set_timeout */
+#define IPMI_SET_TIMEOUT_NO_HB			0
+#define IPMI_SET_TIMEOUT_HB_IF_NECESSARY	1
+#define IPMI_SET_TIMEOUT_FORCE_HB		2
+
+static int ipmi_set_timeout(int do_heartbeat);
+static void ipmi_register_watchdog(int ipmi_intf);
+static void ipmi_unregister_watchdog(int ipmi_intf);
+
+/*
+ * If true, the driver will start running as soon as it is configured
+ * and ready.
+ */
+static int start_now;
+
+static int set_param_timeout(const char *val, const struct kernel_param *kp)
+{
+	char *endp;
+	int  l;
+	int  rv = 0;
+
+	if (!val)
+		return -EINVAL;
+	l = simple_strtoul(val, &endp, 0);
+	if (endp == val)
+		return -EINVAL;
+
+	*((int *)kp->arg) = l;
+	if (watchdog_user)
+		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+	return rv;
+}
+
+static const struct kernel_param_ops param_ops_timeout = {
+	.set = set_param_timeout,
+	.get = param_get_int,
+};
+#define param_check_timeout param_check_int
+
+typedef int (*action_fn)(const char *intval, char *outval);
+
+static int action_op(const char *inval, char *outval);
+static int preaction_op(const char *inval, char *outval);
+static int preop_op(const char *inval, char *outval);
+static void check_parms(void);
+
+static int set_param_str(const char *val, const struct kernel_param *kp)
+{
+	action_fn  fn = (action_fn) kp->arg;
+	int        rv = 0;
+	char       valcp[16];
+	char       *s;
+
+	strncpy(valcp, val, 15);
+	valcp[15] = '\0';
+
+	s = strstrip(valcp);
+
+	rv = fn(s, NULL);
+	if (rv)
+		goto out;
+
+	check_parms();
+	if (watchdog_user)
+		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+ out:
+	return rv;
+}
+
+static int get_param_str(char *buffer, const struct kernel_param *kp)
+{
+	action_fn fn = (action_fn) kp->arg;
+	int rv, len;
+
+	rv = fn(NULL, buffer);
+	if (rv)
+		return rv;
+
+	len = strlen(buffer);
+	buffer[len++] = '\n';
+	buffer[len] = 0;
+
+	return len;
+}
+
+
+static int set_param_wdog_ifnum(const char *val, const struct kernel_param *kp)
+{
+	int rv = param_set_int(val, kp);
+	if (rv)
+		return rv;
+	if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
+		return 0;
+
+	ipmi_unregister_watchdog(watchdog_ifnum);
+	ipmi_register_watchdog(ifnum_to_use);
+	return 0;
+}
+
+static const struct kernel_param_ops param_ops_wdog_ifnum = {
+	.set = set_param_wdog_ifnum,
+	.get = param_get_int,
+};
+
+#define param_check_wdog_ifnum param_check_int
+
+static const struct kernel_param_ops param_ops_str = {
+	.set = set_param_str,
+	.get = get_param_str,
+};
+
+module_param(ifnum_to_use, wdog_ifnum, 0644);
+MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
+		 "timer.  Setting to -1 defaults to the first registered "
+		 "interface");
+
+module_param(timeout, timeout, 0644);
+MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
+
+module_param(pretimeout, timeout, 0644);
+MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
+
+module_param(panic_wdt_timeout, timeout, 0644);
+MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
+
+module_param_cb(action, &param_ops_str, action_op, 0644);
+MODULE_PARM_DESC(action, "Timeout action. One of: "
+		 "reset, none, power_cycle, power_off.");
+
+module_param_cb(preaction, &param_ops_str, preaction_op, 0644);
+MODULE_PARM_DESC(preaction, "Pretimeout action.  One of: "
+		 "pre_none, pre_smi, pre_nmi, pre_int.");
+
+module_param_cb(preop, &param_ops_str, preop_op, 0644);
+MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
+		 "preop_none, preop_panic, preop_give_data.");
+
+module_param(start_now, int, 0444);
+MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
+		 "soon as the driver is loaded.");
+
+module_param(nowayout, bool, 0644);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+		 "(default=CONFIG_WATCHDOG_NOWAYOUT)");
+
+/* Default state of the timer. */
+static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+
+/* Is someone using the watchdog?  Only one user is allowed. */
+static unsigned long ipmi_wdog_open;
+
+/*
+ * If set to 1, the heartbeat command will set the state to reset and
+ * start the timer.  The timer doesn't normally run when the driver is
+ * first opened until the heartbeat is set the first time, this
+ * variable is used to accomplish this.
+ */
+static int ipmi_start_timer_on_heartbeat;
+
+/* IPMI version of the BMC. */
+static unsigned char ipmi_version_major;
+static unsigned char ipmi_version_minor;
+
+/* If a pretimeout occurs, this is used to allow only one panic to happen. */
+static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
+
+#ifdef HAVE_DIE_NMI
+static int testing_nmi;
+static int nmi_handler_registered;
+#endif
+
+static int __ipmi_heartbeat(void);
+
+/*
+ * We use a mutex to make sure that only one thing can send a set a
+ * message at one time.  The mutex is claimed when a message is sent
+ * and freed when both the send and receive messages are free.
+ */
+static atomic_t msg_tofree = ATOMIC_INIT(0);
+static DECLARE_COMPLETION(msg_wait);
+static void msg_free_smi(struct ipmi_smi_msg *msg)
+{
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
+}
+static void msg_free_recv(struct ipmi_recv_msg *msg)
+{
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
+}
+static struct ipmi_smi_msg smi_msg = {
+	.done = msg_free_smi
+};
+static struct ipmi_recv_msg recv_msg = {
+	.done = msg_free_recv
+};
+
+static int __ipmi_set_timeout(struct ipmi_smi_msg  *smi_msg,
+			      struct ipmi_recv_msg *recv_msg,
+			      int                  *send_heartbeat_now)
+{
+	struct kernel_ipmi_msg            msg;
+	unsigned char                     data[6];
+	int                               rv;
+	struct ipmi_system_interface_addr addr;
+	int                               hbnow = 0;
+
+
+	data[0] = 0;
+	WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
+
+	if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
+		if ((ipmi_version_major > 1) ||
+		    ((ipmi_version_major == 1) && (ipmi_version_minor >= 5))) {
+			/* This is an IPMI 1.5-only feature. */
+			data[0] |= WDOG_DONT_STOP_ON_SET;
+		} else {
+			/*
+			 * In ipmi 1.0, setting the timer stops the watchdog, we
+			 * need to start it back up again.
+			 */
+			hbnow = 1;
+		}
+	}
+
+	data[1] = 0;
+	WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
+	if ((pretimeout > 0) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
+	    WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
+	    data[2] = pretimeout;
+	} else {
+	    WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
+	    data[2] = 0; /* No pretimeout. */
+	}
+	data[3] = 0;
+	WDOG_SET_TIMEOUT(data[4], data[5], timeout);
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_SET_TIMER;
+	msg.data = data;
+	msg.data_len = sizeof(data);
+	rv = ipmi_request_supply_msgs(watchdog_user,
+				      (struct ipmi_addr *) &addr,
+				      0,
+				      &msg,
+				      NULL,
+				      smi_msg,
+				      recv_msg,
+				      1);
+	if (rv)
+		pr_warn("set timeout error: %d\n", rv);
+	else if (send_heartbeat_now)
+		*send_heartbeat_now = hbnow;
+
+	return rv;
+}
+
+static int _ipmi_set_timeout(int do_heartbeat)
+{
+	int send_heartbeat_now;
+	int rv;
+
+	if (!watchdog_user)
+		return -ENODEV;
+
+	atomic_set(&msg_tofree, 2);
+
+	rv = __ipmi_set_timeout(&smi_msg,
+				&recv_msg,
+				&send_heartbeat_now);
+	if (rv) {
+		atomic_set(&msg_tofree, 0);
+		return rv;
+	}
+
+	wait_for_completion(&msg_wait);
+
+	if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
+		|| ((send_heartbeat_now)
+		    && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
+		rv = __ipmi_heartbeat();
+
+	return rv;
+}
+
+static int ipmi_set_timeout(int do_heartbeat)
+{
+	int rv;
+
+	mutex_lock(&ipmi_watchdog_mutex);
+	rv = _ipmi_set_timeout(do_heartbeat);
+	mutex_unlock(&ipmi_watchdog_mutex);
+
+	return rv;
+}
+
+static atomic_t panic_done_count = ATOMIC_INIT(0);
+
+static void panic_smi_free(struct ipmi_smi_msg *msg)
+{
+	atomic_dec(&panic_done_count);
+}
+static void panic_recv_free(struct ipmi_recv_msg *msg)
+{
+	atomic_dec(&panic_done_count);
+}
+
+static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg = {
+	.done = panic_smi_free
+};
+static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg = {
+	.done = panic_recv_free
+};
+
+static void panic_halt_ipmi_heartbeat(void)
+{
+	struct kernel_ipmi_msg             msg;
+	struct ipmi_system_interface_addr addr;
+	int rv;
+
+	/*
+	 * Don't reset the timer if we have the timer turned off, that
+	 * re-enables the watchdog.
+	 */
+	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
+		return;
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_RESET_TIMER;
+	msg.data = NULL;
+	msg.data_len = 0;
+	atomic_add(2, &panic_done_count);
+	rv = ipmi_request_supply_msgs(watchdog_user,
+				      (struct ipmi_addr *) &addr,
+				      0,
+				      &msg,
+				      NULL,
+				      &panic_halt_heartbeat_smi_msg,
+				      &panic_halt_heartbeat_recv_msg,
+				      1);
+	if (rv)
+		atomic_sub(2, &panic_done_count);
+}
+
+static struct ipmi_smi_msg panic_halt_smi_msg = {
+	.done = panic_smi_free
+};
+static struct ipmi_recv_msg panic_halt_recv_msg = {
+	.done = panic_recv_free
+};
+
+/*
+ * Special call, doesn't claim any locks.  This is only to be called
+ * at panic or halt time, in run-to-completion mode, when the caller
+ * is the only CPU and the only thing that will be going is these IPMI
+ * calls.
+ */
+static void panic_halt_ipmi_set_timeout(void)
+{
+	int send_heartbeat_now;
+	int rv;
+
+	/* Wait for the messages to be free. */
+	while (atomic_read(&panic_done_count) != 0)
+		ipmi_poll_interface(watchdog_user);
+	atomic_add(2, &panic_done_count);
+	rv = __ipmi_set_timeout(&panic_halt_smi_msg,
+				&panic_halt_recv_msg,
+				&send_heartbeat_now);
+	if (rv) {
+		atomic_sub(2, &panic_done_count);
+		pr_warn("Unable to extend the watchdog timeout\n");
+	} else {
+		if (send_heartbeat_now)
+			panic_halt_ipmi_heartbeat();
+	}
+	while (atomic_read(&panic_done_count) != 0)
+		ipmi_poll_interface(watchdog_user);
+}
+
+static int __ipmi_heartbeat(void)
+{
+	struct kernel_ipmi_msg msg;
+	int rv;
+	struct ipmi_system_interface_addr addr;
+	int timeout_retries = 0;
+
+restart:
+	/*
+	 * Don't reset the timer if we have the timer turned off, that
+	 * re-enables the watchdog.
+	 */
+	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
+		return 0;
+
+	atomic_set(&msg_tofree, 2);
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_RESET_TIMER;
+	msg.data = NULL;
+	msg.data_len = 0;
+	rv = ipmi_request_supply_msgs(watchdog_user,
+				      (struct ipmi_addr *) &addr,
+				      0,
+				      &msg,
+				      NULL,
+				      &smi_msg,
+				      &recv_msg,
+				      1);
+	if (rv) {
+		atomic_set(&msg_tofree, 0);
+		pr_warn("heartbeat send failure: %d\n", rv);
+		return rv;
+	}
+
+	/* Wait for the heartbeat to be sent. */
+	wait_for_completion(&msg_wait);
+
+	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
+		timeout_retries++;
+		if (timeout_retries > 3) {
+			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
+			rv = -EIO;
+			goto out;
+		}
+
+		/*
+		 * The timer was not initialized, that means the BMC was
+		 * probably reset and lost the watchdog information.  Attempt
+		 * to restore the timer's info.  Note that we still hold
+		 * the heartbeat lock, to keep a heartbeat from happening
+		 * in this process, so must say no heartbeat to avoid a
+		 * deadlock on this mutex
+		 */
+		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+		if (rv) {
+			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
+			goto out;
+		}
+
+		/* Might need a heartbeat send, go ahead and do it. */
+		goto restart;
+	} else if (recv_msg.msg.data[0] != 0) {
+		/*
+		 * Got an error in the heartbeat response.  It was already
+		 * reported in ipmi_wdog_msg_handler, but we should return
+		 * an error here.
+		 */
+		rv = -EINVAL;
+	}
+
+out:
+	return rv;
+}
+
+static int _ipmi_heartbeat(void)
+{
+	int rv;
+
+	if (!watchdog_user)
+		return -ENODEV;
+
+	if (ipmi_start_timer_on_heartbeat) {
+		ipmi_start_timer_on_heartbeat = 0;
+		ipmi_watchdog_state = action_val;
+		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
+		/*
+		 * A pretimeout occurred, make sure we set the timeout.
+		 * We don't want to set the action, though, we want to
+		 * leave that alone (thus it can't be combined with the
+		 * above operation.
+		 */
+		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+	} else {
+		rv = __ipmi_heartbeat();
+	}
+
+	return rv;
+}
+
+static int ipmi_heartbeat(void)
+{
+	int rv;
+
+	mutex_lock(&ipmi_watchdog_mutex);
+	rv = _ipmi_heartbeat();
+	mutex_unlock(&ipmi_watchdog_mutex);
+
+	return rv;
+}
+
+static struct watchdog_info ident = {
+	.options	= 0,	/* WDIOF_SETTIMEOUT, */
+	.firmware_version = 1,
+	.identity	= "IPMI"
+};
+
+static int ipmi_ioctl(struct file *file,
+		      unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int i;
+	int val;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		i = copy_to_user(argp, &ident, sizeof(ident));
+		return i ? -EFAULT : 0;
+
+	case WDIOC_SETTIMEOUT:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		timeout = val;
+		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+	case WDIOC_GETTIMEOUT:
+		i = copy_to_user(argp, &timeout, sizeof(timeout));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	case WDIOC_SETPRETIMEOUT:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		pretimeout = val;
+		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+	case WDIOC_GETPRETIMEOUT:
+		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	case WDIOC_KEEPALIVE:
+		return _ipmi_heartbeat();
+
+	case WDIOC_SETOPTIONS:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		if (val & WDIOS_DISABLECARD) {
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+			ipmi_start_timer_on_heartbeat = 0;
+		}
+
+		if (val & WDIOS_ENABLECARD) {
+			ipmi_watchdog_state = action_val;
+			_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+		}
+		return 0;
+
+	case WDIOC_GETSTATUS:
+		val = 0;
+		i = copy_to_user(argp, &val, sizeof(val));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static long ipmi_unlocked_ioctl(struct file *file,
+				unsigned int cmd,
+				unsigned long arg)
+{
+	int ret;
+
+	mutex_lock(&ipmi_watchdog_mutex);
+	ret = ipmi_ioctl(file, cmd, arg);
+	mutex_unlock(&ipmi_watchdog_mutex);
+
+	return ret;
+}
+
+static ssize_t ipmi_write(struct file *file,
+			  const char  __user *buf,
+			  size_t      len,
+			  loff_t      *ppos)
+{
+	int rv;
+
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != len; i++) {
+				char c;
+
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		rv = ipmi_heartbeat();
+		if (rv)
+			return rv;
+	}
+	return len;
+}
+
+static ssize_t ipmi_read(struct file *file,
+			 char        __user *buf,
+			 size_t      count,
+			 loff_t      *ppos)
+{
+	int          rv = 0;
+	wait_queue_entry_t wait;
+
+	if (count <= 0)
+		return 0;
+
+	/*
+	 * Reading returns if the pretimeout has gone off, and it only does
+	 * it once per pretimeout.
+	 */
+	spin_lock_irq(&ipmi_read_lock);
+	if (!data_to_read) {
+		if (file->f_flags & O_NONBLOCK) {
+			rv = -EAGAIN;
+			goto out;
+		}
+
+		init_waitqueue_entry(&wait, current);
+		add_wait_queue(&read_q, &wait);
+		while (!data_to_read) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			spin_unlock_irq(&ipmi_read_lock);
+			schedule();
+			spin_lock_irq(&ipmi_read_lock);
+		}
+		remove_wait_queue(&read_q, &wait);
+
+		if (signal_pending(current)) {
+			rv = -ERESTARTSYS;
+			goto out;
+		}
+	}
+	data_to_read = 0;
+
+ out:
+	spin_unlock_irq(&ipmi_read_lock);
+
+	if (rv == 0) {
+		if (copy_to_user(buf, &data_to_read, 1))
+			rv = -EFAULT;
+		else
+			rv = 1;
+	}
+
+	return rv;
+}
+
+static int ipmi_open(struct inode *ino, struct file *filep)
+{
+	switch (iminor(ino)) {
+	case WATCHDOG_MINOR:
+		if (test_and_set_bit(0, &ipmi_wdog_open))
+			return -EBUSY;
+
+
+		/*
+		 * Don't start the timer now, let it start on the
+		 * first heartbeat.
+		 */
+		ipmi_start_timer_on_heartbeat = 1;
+		return stream_open(ino, filep);
+
+	default:
+		return (-ENODEV);
+	}
+}
+
+static __poll_t ipmi_poll(struct file *file, poll_table *wait)
+{
+	__poll_t mask = 0;
+
+	poll_wait(file, &read_q, wait);
+
+	spin_lock_irq(&ipmi_read_lock);
+	if (data_to_read)
+		mask |= (EPOLLIN | EPOLLRDNORM);
+	spin_unlock_irq(&ipmi_read_lock);
+
+	return mask;
+}
+
+static int ipmi_fasync(int fd, struct file *file, int on)
+{
+	int result;
+
+	result = fasync_helper(fd, file, on, &fasync_q);
+
+	return (result);
+}
+
+static int ipmi_close(struct inode *ino, struct file *filep)
+{
+	if (iminor(ino) == WATCHDOG_MINOR) {
+		if (expect_close == 42) {
+			mutex_lock(&ipmi_watchdog_mutex);
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+			mutex_unlock(&ipmi_watchdog_mutex);
+		} else {
+			pr_crit("Unexpected close, not stopping watchdog!\n");
+			ipmi_heartbeat();
+		}
+		clear_bit(0, &ipmi_wdog_open);
+	}
+
+	expect_close = 0;
+
+	return 0;
+}
+
+static const struct file_operations ipmi_wdog_fops = {
+	.owner   = THIS_MODULE,
+	.read    = ipmi_read,
+	.poll    = ipmi_poll,
+	.write   = ipmi_write,
+	.unlocked_ioctl = ipmi_unlocked_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.open    = ipmi_open,
+	.release = ipmi_close,
+	.fasync  = ipmi_fasync,
+	.llseek  = no_llseek,
+};
+
+static struct miscdevice ipmi_wdog_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &ipmi_wdog_fops
+};
+
+static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
+				  void                 *handler_data)
+{
+	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
+			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
+		pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
+	else if (msg->msg.data[0] != 0)
+		pr_err("response: Error %x on cmd %x\n",
+		       msg->msg.data[0],
+		       msg->msg.cmd);
+
+	ipmi_free_recv_msg(msg);
+}
+
+static void ipmi_wdog_pretimeout_handler(void *handler_data)
+{
+	if (preaction_val != WDOG_PRETIMEOUT_NONE) {
+		if (preop_val == WDOG_PREOP_PANIC) {
+			if (atomic_inc_and_test(&preop_panic_excl))
+				panic("Watchdog pre-timeout");
+		} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
+			unsigned long flags;
+
+			spin_lock_irqsave(&ipmi_read_lock, flags);
+			data_to_read = 1;
+			wake_up_interruptible(&read_q);
+			kill_fasync(&fasync_q, SIGIO, POLL_IN);
+			spin_unlock_irqrestore(&ipmi_read_lock, flags);
+		}
+	}
+
+	/*
+	 * On some machines, the heartbeat will give an error and not
+	 * work unless we re-enable the timer.  So do so.
+	 */
+	atomic_set(&pretimeout_since_last_heartbeat, 1);
+}
+
+static void ipmi_wdog_panic_handler(void *user_data)
+{
+	static int panic_event_handled;
+
+	/*
+	 * On a panic, if we have a panic timeout, make sure to extend
+	 * the watchdog timer to a reasonable value to complete the
+	 * panic, if the watchdog timer is running.  Plus the
+	 * pretimeout is meaningless at panic time.
+	 */
+	if (watchdog_user && !panic_event_handled &&
+	    ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
+		/* Make sure we do this only once. */
+		panic_event_handled = 1;
+
+		timeout = panic_wdt_timeout;
+		pretimeout = 0;
+		panic_halt_ipmi_set_timeout();
+	}
+}
+
+static const struct ipmi_user_hndl ipmi_hndlrs = {
+	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
+	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
+	.ipmi_panic_handler       = ipmi_wdog_panic_handler
+};
+
+static void ipmi_register_watchdog(int ipmi_intf)
+{
+	int rv = -EBUSY;
+
+	if (watchdog_user)
+		goto out;
+
+	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
+		goto out;
+
+	watchdog_ifnum = ipmi_intf;
+
+	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
+	if (rv < 0) {
+		pr_crit("Unable to register with ipmi\n");
+		goto out;
+	}
+
+	rv = ipmi_get_version(watchdog_user,
+			      &ipmi_version_major,
+			      &ipmi_version_minor);
+	if (rv) {
+		pr_warn("Unable to get IPMI version, assuming 1.0\n");
+		ipmi_version_major = 1;
+		ipmi_version_minor = 0;
+	}
+
+	rv = misc_register(&ipmi_wdog_miscdev);
+	if (rv < 0) {
+		ipmi_destroy_user(watchdog_user);
+		watchdog_user = NULL;
+		pr_crit("Unable to register misc device\n");
+	}
+
+#ifdef HAVE_DIE_NMI
+	if (nmi_handler_registered) {
+		int old_pretimeout = pretimeout;
+		int old_timeout = timeout;
+		int old_preop_val = preop_val;
+
+		/*
+		 * Set the pretimeout to go off in a second and give
+		 * ourselves plenty of time to stop the timer.
+		 */
+		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
+		preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
+		pretimeout = 99;
+		timeout = 100;
+
+		testing_nmi = 1;
+
+		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+		if (rv) {
+			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",
+				rv);
+			rv = 0;
+			goto out_restore;
+		}
+
+		msleep(1500);
+
+		if (testing_nmi != 2) {
+			pr_warn("IPMI NMI didn't seem to occur.  The NMI pretimeout will likely not work\n");
+		}
+ out_restore:
+		testing_nmi = 0;
+		preop_val = old_preop_val;
+		pretimeout = old_pretimeout;
+		timeout = old_timeout;
+	}
+#endif
+
+ out:
+	if ((start_now) && (rv == 0)) {
+		/* Run from startup, so start the timer now. */
+		start_now = 0; /* Disable this function after first startup. */
+		ipmi_watchdog_state = action_val;
+		ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+		pr_info("Starting now!\n");
+	} else {
+		/* Stop the timer now. */
+		ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+		ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+	}
+}
+
+static void ipmi_unregister_watchdog(int ipmi_intf)
+{
+	int rv;
+	struct ipmi_user *loc_user = watchdog_user;
+
+	if (!loc_user)
+		return;
+
+	if (watchdog_ifnum != ipmi_intf)
+		return;
+
+	/* Make sure no one can call us any more. */
+	misc_deregister(&ipmi_wdog_miscdev);
+
+	watchdog_user = NULL;
+
+	/*
+	 * Wait to make sure the message makes it out.  The lower layer has
+	 * pointers to our buffers, we want to make sure they are done before
+	 * we release our memory.
+	 */
+	while (atomic_read(&msg_tofree))
+		msg_free_smi(NULL);
+
+	mutex_lock(&ipmi_watchdog_mutex);
+
+	/* Disconnect from IPMI. */
+	rv = ipmi_destroy_user(loc_user);
+	if (rv)
+		pr_warn("error unlinking from IPMI: %d\n",  rv);
+
+	/* If it comes back, restart it properly. */
+	ipmi_start_timer_on_heartbeat = 1;
+
+	mutex_unlock(&ipmi_watchdog_mutex);
+}
+
+#ifdef HAVE_DIE_NMI
+static int
+ipmi_nmi(unsigned int val, struct pt_regs *regs)
+{
+	/*
+	 * If we get here, it's an NMI that's not a memory or I/O
+	 * error.  We can't truly tell if it's from IPMI or not
+	 * without sending a message, and sending a message is almost
+	 * impossible because of locking.
+	 */
+
+	if (testing_nmi) {
+		testing_nmi = 2;
+		return NMI_HANDLED;
+	}
+
+	/* If we are not expecting a timeout, ignore it. */
+	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
+		return NMI_DONE;
+
+	if (preaction_val != WDOG_PRETIMEOUT_NMI)
+		return NMI_DONE;
+
+	/*
+	 * If no one else handled the NMI, we assume it was the IPMI
+	 * watchdog.
+	 */
+	if (preop_val == WDOG_PREOP_PANIC) {
+		/* On some machines, the heartbeat will give
+		   an error and not work unless we re-enable
+		   the timer.   So do so. */
+		atomic_set(&pretimeout_since_last_heartbeat, 1);
+		if (atomic_inc_and_test(&preop_panic_excl))
+			nmi_panic(regs, "pre-timeout");
+	}
+
+	return NMI_HANDLED;
+}
+#endif
+
+static int wdog_reboot_handler(struct notifier_block *this,
+			       unsigned long         code,
+			       void                  *unused)
+{
+	static int reboot_event_handled;
+
+	if ((watchdog_user) && (!reboot_event_handled)) {
+		/* Make sure we only do this once. */
+		reboot_event_handled = 1;
+
+		if (code == SYS_POWER_OFF || code == SYS_HALT) {
+			/* Disable the WDT if we are shutting down. */
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
+			/* Set a long timer to let the reboot happen or
+			   reset if it hangs, but only if the watchdog
+			   timer was already running. */
+			if (timeout < 120)
+				timeout = 120;
+			pretimeout = 0;
+			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
+			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+		}
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block wdog_reboot_notifier = {
+	.notifier_call	= wdog_reboot_handler,
+	.next		= NULL,
+	.priority	= 0
+};
+
+static void ipmi_new_smi(int if_num, struct device *device)
+{
+	ipmi_register_watchdog(if_num);
+}
+
+static void ipmi_smi_gone(int if_num)
+{
+	ipmi_unregister_watchdog(if_num);
+}
+
+static struct ipmi_smi_watcher smi_watcher = {
+	.owner    = THIS_MODULE,
+	.new_smi  = ipmi_new_smi,
+	.smi_gone = ipmi_smi_gone
+};
+
+static int action_op(const char *inval, char *outval)
+{
+	if (outval)
+		strcpy(outval, action);
+
+	if (!inval)
+		return 0;
+
+	if (strcmp(inval, "reset") == 0)
+		action_val = WDOG_TIMEOUT_RESET;
+	else if (strcmp(inval, "none") == 0)
+		action_val = WDOG_TIMEOUT_NONE;
+	else if (strcmp(inval, "power_cycle") == 0)
+		action_val = WDOG_TIMEOUT_POWER_CYCLE;
+	else if (strcmp(inval, "power_off") == 0)
+		action_val = WDOG_TIMEOUT_POWER_DOWN;
+	else
+		return -EINVAL;
+	strcpy(action, inval);
+	return 0;
+}
+
+static int preaction_op(const char *inval, char *outval)
+{
+	if (outval)
+		strcpy(outval, preaction);
+
+	if (!inval)
+		return 0;
+
+	if (strcmp(inval, "pre_none") == 0)
+		preaction_val = WDOG_PRETIMEOUT_NONE;
+	else if (strcmp(inval, "pre_smi") == 0)
+		preaction_val = WDOG_PRETIMEOUT_SMI;
+#ifdef HAVE_DIE_NMI
+	else if (strcmp(inval, "pre_nmi") == 0)
+		preaction_val = WDOG_PRETIMEOUT_NMI;
+#endif
+	else if (strcmp(inval, "pre_int") == 0)
+		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
+	else
+		return -EINVAL;
+	strcpy(preaction, inval);
+	return 0;
+}
+
+static int preop_op(const char *inval, char *outval)
+{
+	if (outval)
+		strcpy(outval, preop);
+
+	if (!inval)
+		return 0;
+
+	if (strcmp(inval, "preop_none") == 0)
+		preop_val = WDOG_PREOP_NONE;
+	else if (strcmp(inval, "preop_panic") == 0)
+		preop_val = WDOG_PREOP_PANIC;
+	else if (strcmp(inval, "preop_give_data") == 0)
+		preop_val = WDOG_PREOP_GIVE_DATA;
+	else
+		return -EINVAL;
+	strcpy(preop, inval);
+	return 0;
+}
+
+static void check_parms(void)
+{
+#ifdef HAVE_DIE_NMI
+	int do_nmi = 0;
+	int rv;
+
+	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
+		do_nmi = 1;
+		if (preop_val == WDOG_PREOP_GIVE_DATA) {
+			pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
+			preop_op("preop_none", NULL);
+			do_nmi = 0;
+		}
+	}
+	if (do_nmi && !nmi_handler_registered) {
+		rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
+						"ipmi");
+		if (rv) {
+			pr_warn("Can't register nmi handler\n");
+			return;
+		} else
+			nmi_handler_registered = 1;
+	} else if (!do_nmi && nmi_handler_registered) {
+		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
+		nmi_handler_registered = 0;
+	}
+#endif
+}
+
+static int __init ipmi_wdog_init(void)
+{
+	int rv;
+
+	if (action_op(action, NULL)) {
+		action_op("reset", NULL);
+		pr_info("Unknown action '%s', defaulting to reset\n", action);
+	}
+
+	if (preaction_op(preaction, NULL)) {
+		preaction_op("pre_none", NULL);
+		pr_info("Unknown preaction '%s', defaulting to none\n",
+			preaction);
+	}
+
+	if (preop_op(preop, NULL)) {
+		preop_op("preop_none", NULL);
+		pr_info("Unknown preop '%s', defaulting to none\n", preop);
+	}
+
+	check_parms();
+
+	register_reboot_notifier(&wdog_reboot_notifier);
+
+	rv = ipmi_smi_watcher_register(&smi_watcher);
+	if (rv) {
+#ifdef HAVE_DIE_NMI
+		if (nmi_handler_registered)
+			unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
+#endif
+		unregister_reboot_notifier(&wdog_reboot_notifier);
+		pr_warn("can't register smi watcher\n");
+		return rv;
+	}
+
+	pr_info("driver initialized\n");
+
+	return 0;
+}
+
+static void __exit ipmi_wdog_exit(void)
+{
+	ipmi_smi_watcher_unregister(&smi_watcher);
+	ipmi_unregister_watchdog(watchdog_ifnum);
+
+#ifdef HAVE_DIE_NMI
+	if (nmi_handler_registered)
+		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
+#endif
+
+	unregister_reboot_notifier(&wdog_reboot_notifier);
+}
+module_exit(ipmi_wdog_exit);
+module_init(ipmi_wdog_init);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
+MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");