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      1  1.30  riastrad /*	$NetBSD: sysmon_wdog.c,v 1.30 2021/12/31 11:05:41 riastradh Exp $	*/
      2   1.1   thorpej 
      3   1.1   thorpej /*-
      4   1.1   thorpej  * Copyright (c) 2000 Zembu Labs, Inc.
      5   1.1   thorpej  * All rights reserved.
      6   1.1   thorpej  *
      7   1.1   thorpej  * Author: Jason R. Thorpe <thorpej (at) zembu.com>
      8   1.1   thorpej  *
      9   1.1   thorpej  * Redistribution and use in source and binary forms, with or without
     10   1.1   thorpej  * modification, are permitted provided that the following conditions
     11   1.1   thorpej  * are met:
     12   1.1   thorpej  * 1. Redistributions of source code must retain the above copyright
     13   1.1   thorpej  *    notice, this list of conditions and the following disclaimer.
     14   1.1   thorpej  * 2. Redistributions in binary form must reproduce the above copyright
     15   1.1   thorpej  *    notice, this list of conditions and the following disclaimer in the
     16   1.1   thorpej  *    documentation and/or other materials provided with the distribution.
     17   1.1   thorpej  * 3. All advertising materials mentioning features or use of this software
     18   1.1   thorpej  *    must display the following acknowledgement:
     19   1.1   thorpej  *	This product includes software developed by Zembu Labs, Inc.
     20   1.1   thorpej  * 4. Neither the name of Zembu Labs nor the names of its employees may
     21   1.1   thorpej  *    be used to endorse or promote products derived from this software
     22   1.1   thorpej  *    without specific prior written permission.
     23   1.1   thorpej  *
     24   1.1   thorpej  * THIS SOFTWARE IS PROVIDED BY ZEMBU LABS, INC. ``AS IS'' AND ANY EXPRESS
     25   1.1   thorpej  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAR-
     26   1.1   thorpej  * RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DIS-
     27   1.1   thorpej  * CLAIMED.  IN NO EVENT SHALL ZEMBU LABS BE LIABLE FOR ANY DIRECT, INDIRECT,
     28   1.1   thorpej  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     29   1.1   thorpej  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     30   1.1   thorpej  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     31   1.1   thorpej  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     32   1.1   thorpej  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     33   1.1   thorpej  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34   1.1   thorpej  */
     35   1.1   thorpej 
     36   1.1   thorpej /*
     37   1.1   thorpej  * Watchdog timer framework for sysmon.  Hardware (and software)
     38   1.1   thorpej  * watchdog timers can register themselves here to provide a
     39   1.1   thorpej  * watchdog function, which provides an abstract interface to the
     40   1.1   thorpej  * user.
     41   1.1   thorpej  */
     42   1.3     lukem 
     43   1.3     lukem #include <sys/cdefs.h>
     44  1.30  riastrad __KERNEL_RCSID(0, "$NetBSD: sysmon_wdog.c,v 1.30 2021/12/31 11:05:41 riastradh Exp $");
     45   1.1   thorpej 
     46   1.1   thorpej #include <sys/param.h>
     47   1.1   thorpej #include <sys/conf.h>
     48   1.1   thorpej #include <sys/errno.h>
     49   1.1   thorpej #include <sys/fcntl.h>
     50  1.24    dyoung #include <sys/condvar.h>
     51  1.21   xtraeme #include <sys/mutex.h>
     52   1.1   thorpej #include <sys/callout.h>
     53   1.1   thorpej #include <sys/kernel.h>
     54   1.1   thorpej #include <sys/systm.h>
     55   1.1   thorpej #include <sys/proc.h>
     56  1.26  pgoyette #include <sys/module.h>
     57  1.27  pgoyette #include <sys/once.h>
     58   1.1   thorpej 
     59   1.1   thorpej #include <dev/sysmon/sysmonvar.h>
     60   1.1   thorpej 
     61  1.20   xtraeme static LIST_HEAD(, sysmon_wdog) sysmon_wdog_list =
     62   1.1   thorpej     LIST_HEAD_INITIALIZER(&sysmon_wdog_list);
     63  1.20   xtraeme static int sysmon_wdog_count;
     64  1.20   xtraeme static kmutex_t sysmon_wdog_list_mtx, sysmon_wdog_mtx;
     65  1.24    dyoung static kcondvar_t sysmon_wdog_cv;
     66  1.20   xtraeme static struct sysmon_wdog *sysmon_armed_wdog;
     67  1.20   xtraeme static callout_t sysmon_wdog_callout;
     68  1.20   xtraeme static void *sysmon_wdog_sdhook;
     69  1.25      matt static void *sysmon_wdog_cphook;
     70  1.17        ad 
     71   1.1   thorpej struct sysmon_wdog *sysmon_wdog_find(const char *);
     72   1.1   thorpej void	sysmon_wdog_release(struct sysmon_wdog *);
     73   1.1   thorpej int	sysmon_wdog_setmode(struct sysmon_wdog *, int, u_int);
     74   1.1   thorpej void	sysmon_wdog_ktickle(void *);
     75  1.25      matt void	sysmon_wdog_critpoll(void *);
     76   1.1   thorpej void	sysmon_wdog_shutdown(void *);
     77  1.24    dyoung void	sysmon_wdog_ref(struct sysmon_wdog *);
     78   1.1   thorpej 
     79  1.30  riastrad static struct sysmon_opvec sysmon_wdog_opvec = {
     80  1.26  pgoyette         sysmonopen_wdog, sysmonclose_wdog, sysmonioctl_wdog,
     81  1.26  pgoyette         NULL, NULL, NULL
     82  1.26  pgoyette };
     83  1.26  pgoyette 
     84  1.29  pgoyette MODULE(MODULE_CLASS_DRIVER, sysmon_wdog, "sysmon");
     85  1.26  pgoyette 
     86  1.27  pgoyette ONCE_DECL(once_wdog);
     87  1.27  pgoyette 
     88  1.27  pgoyette static int
     89  1.27  pgoyette wdog_preinit(void)
     90  1.27  pgoyette {
     91  1.27  pgoyette 
     92  1.27  pgoyette 	mutex_init(&sysmon_wdog_list_mtx, MUTEX_DEFAULT, IPL_NONE);
     93  1.27  pgoyette 	mutex_init(&sysmon_wdog_mtx, MUTEX_DEFAULT, IPL_SOFTCLOCK);
     94  1.27  pgoyette 	cv_init(&sysmon_wdog_cv, "wdogref");
     95  1.28      matt 	callout_init(&sysmon_wdog_callout, 0);
     96  1.27  pgoyette 
     97  1.27  pgoyette 	return 0;
     98  1.27  pgoyette }
     99  1.27  pgoyette 
    100  1.26  pgoyette int
    101  1.20   xtraeme sysmon_wdog_init(void)
    102  1.20   xtraeme {
    103  1.26  pgoyette 	int error;
    104  1.26  pgoyette 
    105  1.27  pgoyette 	(void)RUN_ONCE(&once_wdog, wdog_preinit);
    106  1.27  pgoyette 
    107  1.25      matt 	sysmon_wdog_sdhook = shutdownhook_establish(sysmon_wdog_shutdown, NULL);
    108  1.25      matt 	if (sysmon_wdog_sdhook == NULL)
    109  1.25      matt 		printf("WARNING: unable to register watchdog shutdown hook\n");
    110  1.25      matt 	sysmon_wdog_cphook = critpollhook_establish(sysmon_wdog_critpoll, NULL);
    111  1.25      matt 	if (sysmon_wdog_cphook == NULL)
    112  1.25      matt 		printf("WARNING: unable to register watchdog critpoll hook\n");
    113  1.26  pgoyette 
    114  1.26  pgoyette 	error = sysmon_attach_minor(SYSMON_MINOR_WDOG, &sysmon_wdog_opvec);
    115  1.26  pgoyette 
    116  1.26  pgoyette 	return error;
    117  1.26  pgoyette }
    118  1.26  pgoyette 
    119  1.26  pgoyette int
    120  1.26  pgoyette sysmon_wdog_fini(void)
    121  1.26  pgoyette {
    122  1.26  pgoyette 	int error;
    123  1.26  pgoyette 
    124  1.26  pgoyette 	if ( ! LIST_EMPTY(&sysmon_wdog_list))
    125  1.26  pgoyette 		return EBUSY;
    126  1.26  pgoyette 
    127  1.26  pgoyette 	error = sysmon_attach_minor(SYSMON_MINOR_WDOG, NULL);
    128  1.26  pgoyette 
    129  1.26  pgoyette 	if (error == 0) {
    130  1.26  pgoyette 		callout_destroy(&sysmon_wdog_callout);
    131  1.26  pgoyette 		critpollhook_disestablish(sysmon_wdog_cphook);
    132  1.26  pgoyette 		shutdownhook_disestablish(sysmon_wdog_sdhook);
    133  1.26  pgoyette 		cv_destroy(&sysmon_wdog_cv);
    134  1.26  pgoyette 		mutex_destroy(&sysmon_wdog_mtx);
    135  1.26  pgoyette 		mutex_destroy(&sysmon_wdog_list_mtx);
    136  1.26  pgoyette 	}
    137  1.26  pgoyette 
    138  1.26  pgoyette 	return error;
    139  1.20   xtraeme }
    140  1.20   xtraeme 
    141   1.1   thorpej /*
    142   1.1   thorpej  * sysmonopen_wdog:
    143   1.1   thorpej  *
    144   1.1   thorpej  *	Open the system monitor device.
    145   1.1   thorpej  */
    146   1.1   thorpej int
    147  1.20   xtraeme sysmonopen_wdog(dev_t dev, int flag, int mode, struct lwp *l)
    148   1.1   thorpej {
    149   1.1   thorpej 
    150  1.20   xtraeme 	return 0;
    151   1.1   thorpej }
    152   1.1   thorpej 
    153   1.1   thorpej /*
    154   1.1   thorpej  * sysmonclose_wdog:
    155   1.1   thorpej  *
    156   1.1   thorpej  *	Close the system monitor device.
    157   1.1   thorpej  */
    158   1.1   thorpej int
    159  1.20   xtraeme sysmonclose_wdog(dev_t dev, int flag, int mode, struct lwp *l)
    160   1.1   thorpej {
    161   1.1   thorpej 	struct sysmon_wdog *smw;
    162  1.20   xtraeme 	int error = 0;
    163   1.1   thorpej 
    164   1.1   thorpej 	/*
    165   1.1   thorpej 	 * If this is the last close, and there is a watchdog
    166   1.1   thorpej 	 * running in UTICKLE mode, we need to disable it,
    167   1.1   thorpej 	 * otherwise the system will reset in short order.
    168   1.1   thorpej 	 *
    169   1.1   thorpej 	 * XXX Maybe we should just go into KTICKLE mode?
    170   1.1   thorpej 	 */
    171  1.20   xtraeme 	mutex_enter(&sysmon_wdog_mtx);
    172   1.1   thorpej 	if ((smw = sysmon_armed_wdog) != NULL) {
    173  1.11  drochner 		if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_UTICKLE) {
    174   1.1   thorpej 			error = sysmon_wdog_setmode(smw,
    175   1.1   thorpej 			    WDOG_MODE_DISARMED, smw->smw_period);
    176   1.1   thorpej 			if (error) {
    177   1.1   thorpej 				printf("WARNING: UNABLE TO DISARM "
    178   1.1   thorpej 				    "WATCHDOG %s ON CLOSE!\n",
    179   1.1   thorpej 				    smw->smw_name);
    180   1.1   thorpej 				/*
    181   1.1   thorpej 				 * ...we will probably reboot soon.
    182   1.1   thorpej 				 */
    183   1.1   thorpej 			}
    184   1.1   thorpej 		}
    185   1.1   thorpej 	}
    186  1.20   xtraeme 	mutex_exit(&sysmon_wdog_mtx);
    187   1.1   thorpej 
    188  1.20   xtraeme 	return error;
    189   1.1   thorpej }
    190   1.1   thorpej 
    191   1.1   thorpej /*
    192   1.1   thorpej  * sysmonioctl_wdog:
    193   1.1   thorpej  *
    194   1.1   thorpej  *	Perform a watchdog control request.
    195   1.1   thorpej  */
    196   1.1   thorpej int
    197  1.20   xtraeme sysmonioctl_wdog(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
    198   1.1   thorpej {
    199   1.1   thorpej 	struct sysmon_wdog *smw;
    200  1.20   xtraeme 	int error = 0;
    201   1.1   thorpej 
    202   1.1   thorpej 	switch (cmd) {
    203   1.1   thorpej 	case WDOGIOC_GMODE:
    204   1.1   thorpej 	    {
    205   1.1   thorpej 		struct wdog_mode *wm = (void *) data;
    206   1.1   thorpej 
    207   1.1   thorpej 		wm->wm_name[sizeof(wm->wm_name) - 1] = '\0';
    208   1.1   thorpej 		smw = sysmon_wdog_find(wm->wm_name);
    209   1.1   thorpej 		if (smw == NULL) {
    210   1.1   thorpej 			error = ESRCH;
    211   1.1   thorpej 			break;
    212   1.1   thorpej 		}
    213   1.1   thorpej 
    214   1.1   thorpej 		wm->wm_mode = smw->smw_mode;
    215   1.1   thorpej 		wm->wm_period = smw->smw_period;
    216   1.1   thorpej 		sysmon_wdog_release(smw);
    217   1.1   thorpej 		break;
    218   1.1   thorpej 	    }
    219   1.1   thorpej 
    220   1.1   thorpej 	case WDOGIOC_SMODE:
    221   1.1   thorpej 	    {
    222   1.1   thorpej 		struct wdog_mode *wm = (void *) data;
    223   1.1   thorpej 
    224   1.1   thorpej 		if ((flag & FWRITE) == 0) {
    225   1.1   thorpej 			error = EPERM;
    226   1.1   thorpej 			break;
    227   1.1   thorpej 		}
    228   1.1   thorpej 
    229   1.1   thorpej 		wm->wm_name[sizeof(wm->wm_name) - 1] = '\0';
    230   1.1   thorpej 		smw = sysmon_wdog_find(wm->wm_name);
    231   1.1   thorpej 		if (smw == NULL) {
    232   1.1   thorpej 			error = ESRCH;
    233   1.1   thorpej 			break;
    234   1.1   thorpej 		}
    235   1.1   thorpej 
    236   1.1   thorpej 		if (wm->wm_mode & ~(WDOG_MODE_MASK|WDOG_FEATURE_MASK))
    237   1.1   thorpej 			error = EINVAL;
    238   1.1   thorpej 		else {
    239  1.20   xtraeme 			mutex_enter(&sysmon_wdog_mtx);
    240   1.1   thorpej 			error = sysmon_wdog_setmode(smw, wm->wm_mode,
    241   1.1   thorpej 			    wm->wm_period);
    242  1.20   xtraeme 			mutex_exit(&sysmon_wdog_mtx);
    243   1.1   thorpej 		}
    244   1.1   thorpej 
    245   1.1   thorpej 		sysmon_wdog_release(smw);
    246   1.1   thorpej 		break;
    247   1.1   thorpej 	    }
    248   1.1   thorpej 
    249   1.1   thorpej 	case WDOGIOC_WHICH:
    250   1.1   thorpej 	    {
    251   1.1   thorpej 		struct wdog_mode *wm = (void *) data;
    252   1.1   thorpej 
    253  1.20   xtraeme 		mutex_enter(&sysmon_wdog_mtx);
    254   1.1   thorpej 		if ((smw = sysmon_armed_wdog) != NULL) {
    255   1.1   thorpej 			strcpy(wm->wm_name, smw->smw_name);
    256   1.1   thorpej 			wm->wm_mode = smw->smw_mode;
    257   1.1   thorpej 			wm->wm_period = smw->smw_period;
    258   1.1   thorpej 		} else
    259   1.1   thorpej 			error = ESRCH;
    260  1.20   xtraeme 		mutex_exit(&sysmon_wdog_mtx);
    261   1.1   thorpej 		break;
    262   1.1   thorpej 	    }
    263   1.1   thorpej 
    264   1.1   thorpej 	case WDOGIOC_TICKLE:
    265   1.1   thorpej 		if ((flag & FWRITE) == 0) {
    266   1.1   thorpej 			error = EPERM;
    267   1.1   thorpej 			break;
    268   1.1   thorpej 		}
    269   1.1   thorpej 
    270  1.20   xtraeme 		mutex_enter(&sysmon_wdog_mtx);
    271   1.1   thorpej 		if ((smw = sysmon_armed_wdog) != NULL) {
    272   1.1   thorpej 			error = (*smw->smw_tickle)(smw);
    273   1.1   thorpej 			if (error == 0)
    274  1.12  christos 				smw->smw_tickler = l->l_proc->p_pid;
    275   1.1   thorpej 		} else
    276   1.1   thorpej 			error = ESRCH;
    277  1.20   xtraeme 		mutex_exit(&sysmon_wdog_mtx);
    278   1.1   thorpej 		break;
    279   1.1   thorpej 
    280   1.1   thorpej 	case WDOGIOC_GTICKLER:
    281   1.4    simonb 		if ((smw = sysmon_armed_wdog) != NULL)
    282   1.4    simonb 			*(pid_t *)data = smw->smw_tickler;
    283   1.4    simonb 		else
    284   1.4    simonb 			error = ESRCH;
    285   1.1   thorpej 		break;
    286   1.1   thorpej 
    287   1.1   thorpej 	case WDOGIOC_GWDOGS:
    288   1.1   thorpej 	    {
    289   1.1   thorpej 		struct wdog_conf *wc = (void *) data;
    290   1.1   thorpej 		char *cp;
    291   1.1   thorpej 		int i;
    292   1.1   thorpej 
    293  1.20   xtraeme 		mutex_enter(&sysmon_wdog_list_mtx);
    294   1.1   thorpej 		if (wc->wc_names == NULL)
    295   1.1   thorpej 			wc->wc_count = sysmon_wdog_count;
    296   1.1   thorpej 		else {
    297   1.1   thorpej 			for (i = 0, cp = wc->wc_names,
    298   1.1   thorpej 			       smw = LIST_FIRST(&sysmon_wdog_list);
    299   1.1   thorpej 			     i < sysmon_wdog_count && smw != NULL && error == 0;
    300   1.1   thorpej 			     i++, cp += WDOG_NAMESIZE,
    301   1.1   thorpej 			       smw = LIST_NEXT(smw, smw_list))
    302   1.1   thorpej 				error = copyout(smw->smw_name, cp,
    303   1.1   thorpej 				    strlen(smw->smw_name) + 1);
    304   1.1   thorpej 			wc->wc_count = i;
    305   1.1   thorpej 		}
    306  1.20   xtraeme 		mutex_exit(&sysmon_wdog_list_mtx);
    307   1.1   thorpej 		break;
    308   1.1   thorpej 	    }
    309   1.1   thorpej 
    310   1.1   thorpej 	default:
    311   1.1   thorpej 		error = ENOTTY;
    312   1.1   thorpej 	}
    313   1.1   thorpej 
    314  1.20   xtraeme 	return error;
    315   1.1   thorpej }
    316   1.1   thorpej 
    317   1.1   thorpej /*
    318   1.1   thorpej  * sysmon_wdog_register:
    319   1.1   thorpej  *
    320   1.1   thorpej  *	Register a watchdog device.
    321   1.1   thorpej  */
    322   1.1   thorpej int
    323   1.1   thorpej sysmon_wdog_register(struct sysmon_wdog *smw)
    324   1.1   thorpej {
    325   1.1   thorpej 	struct sysmon_wdog *lsmw;
    326   1.1   thorpej 	int error = 0;
    327   1.1   thorpej 
    328  1.27  pgoyette 	(void)RUN_ONCE(&once_wdog, wdog_preinit);
    329  1.27  pgoyette 
    330  1.20   xtraeme 	mutex_enter(&sysmon_wdog_list_mtx);
    331   1.1   thorpej 
    332  1.23    dyoung 	LIST_FOREACH(lsmw, &sysmon_wdog_list, smw_list) {
    333   1.1   thorpej 		if (strcmp(lsmw->smw_name, smw->smw_name) == 0) {
    334   1.1   thorpej 			error = EEXIST;
    335   1.1   thorpej 			goto out;
    336   1.1   thorpej 		}
    337   1.1   thorpej 	}
    338   1.1   thorpej 
    339   1.1   thorpej 	smw->smw_mode = WDOG_MODE_DISARMED;
    340   1.1   thorpej 	smw->smw_tickler = (pid_t) -1;
    341   1.1   thorpej 	smw->smw_refcnt = 0;
    342   1.1   thorpej 	sysmon_wdog_count++;
    343   1.1   thorpej 	LIST_INSERT_HEAD(&sysmon_wdog_list, smw, smw_list);
    344   1.1   thorpej 
    345   1.1   thorpej  out:
    346  1.20   xtraeme 	mutex_exit(&sysmon_wdog_list_mtx);
    347  1.20   xtraeme 	return error;
    348   1.1   thorpej }
    349   1.1   thorpej 
    350   1.1   thorpej /*
    351   1.1   thorpej  * sysmon_wdog_unregister:
    352   1.1   thorpej  *
    353   1.1   thorpej  *	Unregister a watchdog device.
    354   1.1   thorpej  */
    355  1.24    dyoung int
    356   1.1   thorpej sysmon_wdog_unregister(struct sysmon_wdog *smw)
    357   1.1   thorpej {
    358  1.24    dyoung 	int rc = 0;
    359   1.1   thorpej 
    360  1.20   xtraeme 	mutex_enter(&sysmon_wdog_list_mtx);
    361  1.24    dyoung 	while (smw->smw_refcnt > 0 && rc == 0) {
    362  1.24    dyoung 		aprint_debug("%s: %d users remain\n", smw->smw_name,
    363  1.24    dyoung 		    smw->smw_refcnt);
    364  1.24    dyoung 		rc = cv_wait_sig(&sysmon_wdog_cv, &sysmon_wdog_list_mtx);
    365  1.24    dyoung 	}
    366  1.24    dyoung 	if (rc == 0) {
    367  1.24    dyoung 		sysmon_wdog_count--;
    368  1.24    dyoung 		LIST_REMOVE(smw, smw_list);
    369  1.24    dyoung 	}
    370  1.20   xtraeme 	mutex_exit(&sysmon_wdog_list_mtx);
    371  1.24    dyoung 	return rc;
    372   1.1   thorpej }
    373   1.1   thorpej 
    374   1.1   thorpej /*
    375  1.25      matt  * sysmon_wdog_critpoll:
    376  1.25      matt  *
    377  1.25      matt  *	Perform critical operations during long polling periods
    378  1.25      matt  */
    379  1.25      matt void
    380  1.25      matt sysmon_wdog_critpoll(void *arg)
    381  1.25      matt {
    382  1.25      matt 	struct sysmon_wdog *smw = sysmon_armed_wdog;
    383  1.25      matt 
    384  1.25      matt 	if (smw == NULL)
    385  1.25      matt 		return;
    386  1.25      matt 
    387  1.25      matt 	if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_KTICKLE) {
    388  1.25      matt 		if ((*smw->smw_tickle)(smw) != 0) {
    389  1.25      matt 			printf("WARNING: KERNEL TICKLE OF WATCHDOG %s "
    390  1.25      matt 			    "FAILED!\n", smw->smw_name);
    391  1.25      matt 		}
    392  1.25      matt 	}
    393  1.25      matt }
    394  1.25      matt 
    395  1.25      matt /*
    396   1.1   thorpej  * sysmon_wdog_find:
    397   1.1   thorpej  *
    398   1.1   thorpej  *	Find a watchdog device.  We increase the reference
    399   1.1   thorpej  *	count on a match.
    400   1.1   thorpej  */
    401   1.1   thorpej struct sysmon_wdog *
    402   1.1   thorpej sysmon_wdog_find(const char *name)
    403   1.1   thorpej {
    404   1.1   thorpej 	struct sysmon_wdog *smw;
    405   1.1   thorpej 
    406  1.20   xtraeme 	mutex_enter(&sysmon_wdog_list_mtx);
    407   1.1   thorpej 
    408  1.23    dyoung 	LIST_FOREACH(smw, &sysmon_wdog_list, smw_list) {
    409   1.1   thorpej 		if (strcmp(smw->smw_name, name) == 0)
    410   1.1   thorpej 			break;
    411   1.1   thorpej 	}
    412   1.1   thorpej 
    413   1.1   thorpej 	if (smw != NULL)
    414   1.1   thorpej 		smw->smw_refcnt++;
    415   1.1   thorpej 
    416  1.20   xtraeme 	mutex_exit(&sysmon_wdog_list_mtx);
    417  1.20   xtraeme 	return smw;
    418   1.1   thorpej }
    419   1.1   thorpej 
    420   1.1   thorpej /*
    421   1.1   thorpej  * sysmon_wdog_release:
    422   1.1   thorpej  *
    423   1.1   thorpej  *	Release a watchdog device.
    424   1.1   thorpej  */
    425   1.1   thorpej void
    426   1.1   thorpej sysmon_wdog_release(struct sysmon_wdog *smw)
    427   1.1   thorpej {
    428   1.1   thorpej 
    429  1.20   xtraeme 	mutex_enter(&sysmon_wdog_list_mtx);
    430   1.1   thorpej 	KASSERT(smw->smw_refcnt != 0);
    431   1.1   thorpej 	smw->smw_refcnt--;
    432  1.24    dyoung 	cv_signal(&sysmon_wdog_cv);
    433  1.24    dyoung 	mutex_exit(&sysmon_wdog_list_mtx);
    434  1.24    dyoung }
    435  1.24    dyoung 
    436  1.24    dyoung void
    437  1.24    dyoung sysmon_wdog_ref(struct sysmon_wdog *smw)
    438  1.24    dyoung {
    439  1.24    dyoung 	mutex_enter(&sysmon_wdog_list_mtx);
    440  1.24    dyoung 	smw->smw_refcnt++;
    441  1.20   xtraeme 	mutex_exit(&sysmon_wdog_list_mtx);
    442   1.1   thorpej }
    443   1.1   thorpej 
    444   1.1   thorpej /*
    445   1.1   thorpej  * sysmon_wdog_setmode:
    446   1.1   thorpej  *
    447   1.1   thorpej  *	Set the mode of a watchdog device.
    448   1.1   thorpej  */
    449   1.1   thorpej int
    450   1.1   thorpej sysmon_wdog_setmode(struct sysmon_wdog *smw, int mode, u_int period)
    451   1.1   thorpej {
    452   1.1   thorpej 	u_int operiod = smw->smw_period;
    453   1.1   thorpej 	int omode = smw->smw_mode;
    454   1.1   thorpej 	int error = 0;
    455   1.1   thorpej 
    456   1.1   thorpej 	smw->smw_period = period;
    457   1.1   thorpej 	smw->smw_mode = mode;
    458   1.1   thorpej 
    459   1.1   thorpej 	switch (mode & WDOG_MODE_MASK) {
    460   1.1   thorpej 	case WDOG_MODE_DISARMED:
    461   1.1   thorpej 		if (smw != sysmon_armed_wdog) {
    462   1.1   thorpej 			error = EINVAL;
    463   1.1   thorpej 			goto out;
    464   1.1   thorpej 		}
    465   1.1   thorpej 		break;
    466   1.1   thorpej 
    467   1.1   thorpej 	case WDOG_MODE_KTICKLE:
    468   1.1   thorpej 	case WDOG_MODE_UTICKLE:
    469  1.10       smb 	case WDOG_MODE_ETICKLE:
    470   1.1   thorpej 		if (sysmon_armed_wdog != NULL) {
    471   1.1   thorpej 			error = EBUSY;
    472   1.1   thorpej 			goto out;
    473   1.1   thorpej 		}
    474   1.1   thorpej 		break;
    475   1.1   thorpej 
    476   1.1   thorpej 	default:
    477   1.1   thorpej 		error = EINVAL;
    478   1.1   thorpej 		goto out;
    479   1.1   thorpej 	}
    480   1.1   thorpej 
    481   1.1   thorpej 	error = (*smw->smw_setmode)(smw);
    482   1.1   thorpej 
    483   1.1   thorpej  out:
    484   1.1   thorpej 	if (error) {
    485   1.1   thorpej 		smw->smw_period = operiod;
    486   1.1   thorpej 		smw->smw_mode = omode;
    487   1.1   thorpej 	} else {
    488   1.1   thorpej 		if ((mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
    489   1.2   thorpej 			sysmon_armed_wdog = NULL;
    490   1.1   thorpej 			smw->smw_tickler = (pid_t) -1;
    491  1.24    dyoung 			sysmon_wdog_release(smw);
    492   1.1   thorpej 			if ((omode & WDOG_MODE_MASK) == WDOG_MODE_KTICKLE)
    493   1.1   thorpej 				callout_stop(&sysmon_wdog_callout);
    494   1.1   thorpej 		} else {
    495   1.1   thorpej 			sysmon_armed_wdog = smw;
    496  1.24    dyoung 			sysmon_wdog_ref(smw);
    497   1.1   thorpej 			if ((mode & WDOG_MODE_MASK) == WDOG_MODE_KTICKLE) {
    498   1.1   thorpej 				callout_reset(&sysmon_wdog_callout,
    499   1.1   thorpej 				    WDOG_PERIOD_TO_TICKS(smw->smw_period) / 2,
    500   1.1   thorpej 				    sysmon_wdog_ktickle, NULL);
    501   1.1   thorpej 			}
    502   1.1   thorpej 		}
    503   1.1   thorpej 	}
    504  1.20   xtraeme 	return error;
    505   1.1   thorpej }
    506   1.1   thorpej 
    507   1.1   thorpej /*
    508   1.1   thorpej  * sysmon_wdog_ktickle:
    509   1.1   thorpej  *
    510   1.1   thorpej  *	Kernel watchdog tickle routine.
    511   1.1   thorpej  */
    512   1.1   thorpej void
    513  1.14  christos sysmon_wdog_ktickle(void *arg)
    514   1.1   thorpej {
    515   1.1   thorpej 	struct sysmon_wdog *smw;
    516   1.1   thorpej 
    517  1.20   xtraeme 	mutex_enter(&sysmon_wdog_mtx);
    518   1.1   thorpej 	if ((smw = sysmon_armed_wdog) != NULL) {
    519   1.1   thorpej 		if ((*smw->smw_tickle)(smw) != 0) {
    520   1.1   thorpej 			printf("WARNING: KERNEL TICKLE OF WATCHDOG %s "
    521   1.1   thorpej 			    "FAILED!\n", smw->smw_name);
    522   1.1   thorpej 			/*
    523   1.1   thorpej 			 * ...we will probably reboot soon.
    524   1.1   thorpej 			 */
    525   1.1   thorpej 		}
    526   1.1   thorpej 		callout_reset(&sysmon_wdog_callout,
    527   1.1   thorpej 		    WDOG_PERIOD_TO_TICKS(smw->smw_period) / 2,
    528   1.1   thorpej 		    sysmon_wdog_ktickle, NULL);
    529   1.1   thorpej 	}
    530  1.20   xtraeme 	mutex_exit(&sysmon_wdog_mtx);
    531   1.1   thorpej }
    532   1.1   thorpej 
    533   1.1   thorpej /*
    534   1.1   thorpej  * sysmon_wdog_shutdown:
    535   1.1   thorpej  *
    536   1.1   thorpej  *	Perform shutdown-time operations.
    537   1.1   thorpej  */
    538   1.1   thorpej void
    539  1.14  christos sysmon_wdog_shutdown(void *arg)
    540   1.1   thorpej {
    541   1.1   thorpej 	struct sysmon_wdog *smw;
    542   1.1   thorpej 
    543   1.1   thorpej 	/*
    544   1.1   thorpej 	 * XXX Locking here?  I don't think it's necessary.
    545   1.1   thorpej 	 */
    546   1.1   thorpej 
    547   1.1   thorpej 	if ((smw = sysmon_armed_wdog) != NULL) {
    548   1.1   thorpej 		if (sysmon_wdog_setmode(smw, WDOG_MODE_DISARMED,
    549   1.1   thorpej 		    smw->smw_period))
    550   1.1   thorpej 			printf("WARNING: FAILED TO SHUTDOWN WATCHDOG %s!\n",
    551   1.1   thorpej 			    smw->smw_name);
    552   1.1   thorpej 	}
    553   1.1   thorpej }
    554  1.30  riastrad 
    555  1.30  riastrad static int
    556  1.26  pgoyette sysmon_wdog_modcmd(modcmd_t cmd, void *arg)
    557  1.26  pgoyette {
    558  1.26  pgoyette         int ret;
    559  1.30  riastrad 
    560  1.26  pgoyette         switch (cmd) {
    561  1.26  pgoyette         case MODULE_CMD_INIT:
    562  1.26  pgoyette                 ret = sysmon_wdog_init();
    563  1.26  pgoyette                 break;
    564  1.26  pgoyette         case MODULE_CMD_FINI:
    565  1.26  pgoyette                 ret = sysmon_wdog_fini();
    566  1.30  riastrad                 break;
    567  1.26  pgoyette         case MODULE_CMD_STAT:
    568  1.26  pgoyette         default:
    569  1.26  pgoyette                 ret = ENOTTY;
    570  1.26  pgoyette         }
    571  1.30  riastrad 
    572  1.30  riastrad         return ret;
    573  1.26  pgoyette }
    574