ipmi_watchdog.c

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/*
 * ipmi_watchdog.c
 *
 * A watchdog timer based upon the IPMI interface.
 *
 * Author: MontaVista Software, Inc.
 *         Corey Minyard <[email protected]>
 *         [email protected]
 *
 * Copyright 2002 MontaVista Software Inc.
 *
 *  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; either version 2 of the License, or (at your
 *  option) any later version.
 *
 *
 *  THIS SOFTWARE IS PROVIDED ``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.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */

#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 <asm/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>

#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

#define PFX "IPMI Watchdog: "

/*
 * 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 ipmi_user_t 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 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 char 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 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, 16);
    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;

    rv = fn(NULL, buffer);
    if (rv)
        return rv;
    return strlen(buffer);
}


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 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 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_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;

/* If shutting down via IPMI, we ignore the heartbeat. */
static int ipmi_ignore_heartbeat;

/* 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
 * timeout at one time, because we only have one copy of the data.
 * The mutex is claimed when the set_timeout is sent and freed
 * when both messages are free.
 */
static atomic_t set_timeout_tofree = ATOMIC_INIT(0);
static DEFINE_MUTEX(set_timeout_lock);
static DECLARE_COMPLETION(set_timeout_wait);
static void set_timeout_free_smi(struct ipmi_smi_msg *msg)
{
    if (atomic_dec_and_test(&set_timeout_tofree))
        complete(&set_timeout_wait);
}
static void set_timeout_free_recv(struct ipmi_recv_msg *msg)
{
    if (atomic_dec_and_test(&set_timeout_tofree))
        complete(&set_timeout_wait);
}
static struct ipmi_smi_msg set_timeout_smi_msg = {
    .done = set_timeout_free_smi
};
static struct ipmi_recv_msg set_timeout_recv_msg = {
    .done = set_timeout_free_recv
};

static int i_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;


    /* These can be cleared as we are setting the timeout. */
    pretimeout_since_last_heartbeat = 0;

    data[0] = 0;
    WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);

    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 if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
        /*
         * 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) {
        printk(KERN_WARNING PFX "set timeout error: %d\n",
               rv);
    }

    if (send_heartbeat_now)
        *send_heartbeat_now = hbnow;

    return rv;
}

static int ipmi_set_timeout(int do_heartbeat)
{
    int send_heartbeat_now;
    int rv;


    /* We can only send one of these at a time. */
    mutex_lock(&set_timeout_lock);

    atomic_set(&set_timeout_tofree, 2);

    rv = i_ipmi_set_timeout(&set_timeout_smi_msg,
                &set_timeout_recv_msg,
                &send_heartbeat_now);
    if (rv) {
        mutex_unlock(&set_timeout_lock);
        goto out;
    }

    wait_for_completion(&set_timeout_wait);

    mutex_unlock(&set_timeout_lock);

    if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
        || ((send_heartbeat_now)
        && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
        rv = ipmi_heartbeat();

out:
    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 = i_ipmi_set_timeout(&panic_halt_smi_msg,
                &panic_halt_recv_msg,
                &send_heartbeat_now);
    if (rv) {
        atomic_sub(2, &panic_done_count);
        printk(KERN_WARNING PFX
               "Unable to extend the watchdog timeout.");
    } else {
        if (send_heartbeat_now)
            panic_halt_ipmi_heartbeat();
    }
    while (atomic_read(&panic_done_count) != 0)
        ipmi_poll_interface(watchdog_user);
}

/*
 * We use a mutex to make sure that only one thing can send a
 * heartbeat at one time, because we only have one copy of the data.
 * The semaphore is claimed when the set_timeout is sent and freed
 * when both messages are free.
 */
static atomic_t heartbeat_tofree = ATOMIC_INIT(0);
static DEFINE_MUTEX(heartbeat_lock);
static DECLARE_COMPLETION(heartbeat_wait);
static void heartbeat_free_smi(struct ipmi_smi_msg *msg)
{
    if (atomic_dec_and_test(&heartbeat_tofree))
        complete(&heartbeat_wait);
}
static void heartbeat_free_recv(struct ipmi_recv_msg *msg)
{
    if (atomic_dec_and_test(&heartbeat_tofree))
        complete(&heartbeat_wait);
}
static struct ipmi_smi_msg heartbeat_smi_msg = {
    .done = heartbeat_free_smi
};
static struct ipmi_recv_msg heartbeat_recv_msg = {
    .done = heartbeat_free_recv
};

static int ipmi_heartbeat(void)
{
    struct kernel_ipmi_msg            msg;
    int                               rv;
    struct ipmi_system_interface_addr addr;
    int               timeout_retries = 0;

    if (ipmi_ignore_heartbeat)
        return 0;

    if (ipmi_start_timer_on_heartbeat) {
        ipmi_start_timer_on_heartbeat = 0;
        ipmi_watchdog_state = action_val;
        return ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
    } else if (pretimeout_since_last_heartbeat) {
        /*
         * 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.
         */
        return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
    }

    mutex_lock(&heartbeat_lock);

restart:
    atomic_set(&heartbeat_tofree, 2);

    /*
     * Don't reset the timer if we have the timer turned off, that
     * re-enables the watchdog.
     */
    if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE) {
        mutex_unlock(&heartbeat_lock);
        return 0;
    }

    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,
                      &heartbeat_smi_msg,
                      &heartbeat_recv_msg,
                      1);
    if (rv) {
        mutex_unlock(&heartbeat_lock);
        printk(KERN_WARNING PFX "heartbeat failure: %d\n",
               rv);
        return rv;
    }

    /* Wait for the heartbeat to be sent. */
    wait_for_completion(&heartbeat_wait);

    if (heartbeat_recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
        timeout_retries++;
        if (timeout_retries > 3) {
            printk(KERN_ERR PFX ": Unable to restore the IPMI"
                   " watchdog's settings, giving up.\n");
            rv = -EIO;
            goto out_unlock;
        }

        /*
         * 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) {
            printk(KERN_ERR PFX ": Unable to send the command to"
                   " set the watchdog's settings, giving up.\n");
            goto out_unlock;
        }

        /* We might need a new heartbeat, so do it now */
        goto restart;
    } else if (heartbeat_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_unlock:
    mutex_unlock(&heartbeat_lock);

    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_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(&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(&ipmi_read_lock);
            schedule();
            spin_lock(&ipmi_read_lock);
        }
        remove_wait_queue(&read_q, &wait);

        if (signal_pending(current)) {
            rv = -ERESTARTSYS;
            goto out;
        }
    }
    data_to_read = 0;

 out:
    spin_unlock(&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 nonseekable_open(ino, filep);

    default:
        return (-ENODEV);
    }
}

static unsigned int ipmi_poll(struct file *file, poll_table *wait)
{
    unsigned int mask = 0;

    poll_wait(file, &read_q, wait);

    spin_lock(&ipmi_read_lock);
    if (data_to_read)
        mask |= (POLLIN | POLLRDNORM);
    spin_unlock(&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) {
            ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
            ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
        } else {
            printk(KERN_CRIT PFX
                   "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,
    .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)
        printk(KERN_INFO PFX "response: The IPMI controller appears"
               " to have been reset, will attempt to reinitialize"
               " the watchdog timer\n");
    else if (msg->msg.data[0] != 0)
        printk(KERN_ERR PFX "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) {
            spin_lock(&ipmi_read_lock);
            data_to_read = 1;
            wake_up_interruptible(&read_q);
            kill_fasync(&fasync_q, SIGIO, POLL_IN);

            spin_unlock(&ipmi_read_lock);
        }
    }

    /*
     * On some machines, the heartbeat will give an error and not
     * work unless we re-enable the timer.  So do so.
     */
    pretimeout_since_last_heartbeat = 1;
}

static struct ipmi_user_hndl ipmi_hndlrs = {
    .ipmi_recv_hndl           = ipmi_wdog_msg_handler,
    .ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_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) {
        printk(KERN_CRIT PFX "Unable to register with ipmi\n");
        goto out;
    }

    ipmi_get_version(watchdog_user,
             &ipmi_version_major,
             &ipmi_version_minor);

    rv = misc_register(&ipmi_wdog_miscdev);
    if (rv < 0) {
        ipmi_destroy_user(watchdog_user);
        watchdog_user = NULL;
        printk(KERN_CRIT PFX "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) {
            printk(KERN_WARNING PFX "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) {
            printk(KERN_WARNING PFX "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);
        printk(KERN_INFO PFX "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;

    if (!watchdog_user)
        goto out;

    if (watchdog_ifnum != ipmi_intf)
        goto out;

    /* Make sure no one can call us any more. */
    misc_deregister(&ipmi_wdog_miscdev);

    /*
     * 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(&set_timeout_tofree))
        schedule_timeout_uninterruptible(1);

    /* Disconnect from IPMI. */
    rv = ipmi_destroy_user(watchdog_user);
    if (rv) {
        printk(KERN_WARNING PFX "error unlinking from IPMI: %d\n",
               rv);
    }
    watchdog_user = NULL;

 out:
    return;
}

#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. */
        pretimeout_since_last_heartbeat = 1;
        if (atomic_inc_and_test(&preop_panic_excl))
            panic(PFX "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 happens, but
               reboot if it hangs, but only if the watchdog
               timer was already running. */
            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 int wdog_panic_handler(struct notifier_block *this,
                  unsigned long         event,
                  void                  *unused)
{
    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 = 255;
        pretimeout = 0;
        panic_halt_ipmi_set_timeout();
    }

    return NOTIFY_OK;
}

static struct notifier_block wdog_panic_notifier = {
    .notifier_call  = wdog_panic_handler,
    .next       = NULL,
    .priority   = 150   /* priority: INT_MAX >= x >= 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) {
            printk(KERN_WARNING PFX "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) {
            printk(KERN_WARNING PFX
                   "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);
        printk(KERN_INFO PFX "Unknown action '%s', defaulting to"
               " reset\n", action);
    }

    if (preaction_op(preaction, NULL)) {
        preaction_op("pre_none", NULL);
        printk(KERN_INFO PFX "Unknown preaction '%s', defaulting to"
               " none\n", preaction);
    }

    if (preop_op(preop, NULL)) {
        preop_op("preop_none", NULL);
        printk(KERN_INFO PFX "Unknown preop '%s', defaulting to"
               " none\n", preop);
    }

    check_parms();

    register_reboot_notifier(&wdog_reboot_notifier);
    atomic_notifier_chain_register(&panic_notifier_list,
            &wdog_panic_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
        atomic_notifier_chain_unregister(&panic_notifier_list,
                         &wdog_panic_notifier);
        unregister_reboot_notifier(&wdog_reboot_notifier);
        printk(KERN_WARNING PFX "can't register smi watcher\n");
        return rv;
    }

    printk(KERN_INFO PFX "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

    atomic_notifier_chain_unregister(&panic_notifier_list,
                     &wdog_panic_notifier);
    unregister_reboot_notifier(&wdog_reboot_notifier);
}
module_exit(ipmi_wdog_exit);
module_init(ipmi_wdog_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Corey Minyard <[email protected]>");
MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");