ipmi_watchdog.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * ipmi_watchdog.c
   4 *
   5 * A watchdog timer based upon the IPMI interface.
   6 *
   7 * Author: MontaVista Software, Inc.
   8 *         Corey Minyard <minyard@mvista.com>
   9 *         source@mvista.com
  10 *
  11 * Copyright 2002 MontaVista Software Inc.
  12 */
  13
  14#define pr_fmt(fmt) "IPMI Watchdog: " fmt
  15
  16#include <linux/module.h>
  17#include <linux/moduleparam.h>
  18#include <linux/ipmi.h>
  19#include <linux/ipmi_smi.h>
  20#include <linux/mutex.h>
  21#include <linux/watchdog.h>
  22#include <linux/miscdevice.h>
  23#include <linux/init.h>
  24#include <linux/completion.h>
  25#include <linux/kdebug.h>
  26#include <linux/kstrtox.h>
  27#include <linux/rwsem.h>
  28#include <linux/errno.h>
  29#include <linux/uaccess.h>
  30#include <linux/notifier.h>
  31#include <linux/nmi.h>
  32#include <linux/reboot.h>
  33#include <linux/wait.h>
  34#include <linux/poll.h>
  35#include <linux/string.h>
  36#include <linux/ctype.h>
  37#include <linux/delay.h>
  38#include <linux/atomic.h>
  39#include <linux/sched/signal.h>
  40
  41#ifdef CONFIG_X86
  42/*
  43 * This is ugly, but I've determined that x86 is the only architecture
  44 * that can reasonably support the IPMI NMI watchdog timeout at this
  45 * time.  If another architecture adds this capability somehow, it
  46 * will have to be a somewhat different mechanism and I have no idea
  47 * how it will work.  So in the unlikely event that another
  48 * architecture supports this, we can figure out a good generic
  49 * mechanism for it at that time.
  50 */
  51#include <asm/kdebug.h>
  52#include <asm/nmi.h>
  53#define HAVE_DIE_NMI
  54#endif
  55
  56/*
  57 * The IPMI command/response information for the watchdog timer.
  58 */
  59
  60/* values for byte 1 of the set command, byte 2 of the get response. */
  61#define WDOG_DONT_LOG		(1 << 7)
  62#define WDOG_DONT_STOP_ON_SET	(1 << 6)
  63#define WDOG_SET_TIMER_USE(byte, use) \
  64	byte = ((byte) & 0xf8) | ((use) & 0x7)
  65#define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
  66#define WDOG_TIMER_USE_BIOS_FRB2	1
  67#define WDOG_TIMER_USE_BIOS_POST	2
  68#define WDOG_TIMER_USE_OS_LOAD		3
  69#define WDOG_TIMER_USE_SMS_OS		4
  70#define WDOG_TIMER_USE_OEM		5
  71
  72/* values for byte 2 of the set command, byte 3 of the get response. */
  73#define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
  74	byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
  75#define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
  76#define WDOG_PRETIMEOUT_NONE		0
  77#define WDOG_PRETIMEOUT_SMI		1
  78#define WDOG_PRETIMEOUT_NMI		2
  79#define WDOG_PRETIMEOUT_MSG_INT		3
  80
  81/* Operations that can be performed on a pretimout. */
  82#define WDOG_PREOP_NONE		0
  83#define WDOG_PREOP_PANIC	1
  84/* Cause data to be available to read.  Doesn't work in NMI mode. */
  85#define WDOG_PREOP_GIVE_DATA	2
  86
  87/* Actions to perform on a full timeout. */
  88#define WDOG_SET_TIMEOUT_ACT(byte, use) \
  89	byte = ((byte) & 0xf8) | ((use) & 0x7)
  90#define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
  91#define WDOG_TIMEOUT_NONE		0
  92#define WDOG_TIMEOUT_RESET		1
  93#define WDOG_TIMEOUT_POWER_DOWN		2
  94#define WDOG_TIMEOUT_POWER_CYCLE	3
  95
  96/*
  97 * Byte 3 of the get command, byte 4 of the get response is the
  98 * pre-timeout in seconds.
  99 */
 100
 101/* Bits for setting byte 4 of the set command, byte 5 of the get response. */
 102#define WDOG_EXPIRE_CLEAR_BIOS_FRB2	(1 << 1)
 103#define WDOG_EXPIRE_CLEAR_BIOS_POST	(1 << 2)
 104#define WDOG_EXPIRE_CLEAR_OS_LOAD	(1 << 3)
 105#define WDOG_EXPIRE_CLEAR_SMS_OS	(1 << 4)
 106#define WDOG_EXPIRE_CLEAR_OEM		(1 << 5)
 107
 108/*
 109 * Setting/getting the watchdog timer value.  This is for bytes 5 and
 110 * 6 (the timeout time) of the set command, and bytes 6 and 7 (the
 111 * timeout time) and 8 and 9 (the current countdown value) of the
 112 * response.  The timeout value is given in seconds (in the command it
 113 * is 100ms intervals).
 114 */
 115#define WDOG_SET_TIMEOUT(byte1, byte2, val) \
 116	(byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
 117#define WDOG_GET_TIMEOUT(byte1, byte2) \
 118	(((byte1) | ((byte2) << 8)) / 10)
 119
 120#define IPMI_WDOG_RESET_TIMER		0x22
 121#define IPMI_WDOG_SET_TIMER		0x24
 122#define IPMI_WDOG_GET_TIMER		0x25
 123
 124#define IPMI_WDOG_TIMER_NOT_INIT_RESP	0x80
 125
 126static DEFINE_MUTEX(ipmi_watchdog_mutex);
 127static bool nowayout = WATCHDOG_NOWAYOUT;
 128
 129static struct ipmi_user *watchdog_user;
 130static int watchdog_ifnum;
 131
 132/* Default the timeout to 10 seconds. */
 133static int timeout = 10;
 134
 135/* The pre-timeout is disabled by default. */
 136static int pretimeout;
 137
 138/* Default timeout to set on panic */
 139static int panic_wdt_timeout = 255;
 140
 141/* Default action is to reset the board on a timeout. */
 142static unsigned char action_val = WDOG_TIMEOUT_RESET;
 143
 144static char action[16] = "reset";
 145
 146static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
 147
 148static char preaction[16] = "pre_none";
 149
 150static unsigned char preop_val = WDOG_PREOP_NONE;
 151
 152static char preop[16] = "preop_none";
 153static DEFINE_MUTEX(ipmi_read_mutex);
 154static char data_to_read;
 155static DECLARE_WAIT_QUEUE_HEAD(read_q);
 156static struct fasync_struct *fasync_q;
 157static atomic_t pretimeout_since_last_heartbeat;
 158static char expect_close;
 159
 160static int ifnum_to_use = -1;
 161
 162/* Parameters to ipmi_set_timeout */
 163#define IPMI_SET_TIMEOUT_NO_HB			0
 164#define IPMI_SET_TIMEOUT_HB_IF_NECESSARY	1
 165#define IPMI_SET_TIMEOUT_FORCE_HB		2
 166
 167static int ipmi_set_timeout(int do_heartbeat);
 168static void ipmi_register_watchdog(int ipmi_intf);
 169static void ipmi_unregister_watchdog(int ipmi_intf);
 170
 171/*
 172 * If true, the driver will start running as soon as it is configured
 173 * and ready.
 174 */
 175static int start_now;
 176
 177static int set_param_timeout(const char *val, const struct kernel_param *kp)
 178{
 179	char *endp;
 180	int  l;
 181	int  rv = 0;
 182
 183	if (!val)
 184		return -EINVAL;
 185	l = simple_strtoul(val, &endp, 0);
 186	if (endp == val)
 187		return -EINVAL;
 188
 189	*((int *)kp->arg) = l;
 190	if (watchdog_user)
 191		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 192
 193	return rv;
 194}
 195
 196static const struct kernel_param_ops param_ops_timeout = {
 197	.set = set_param_timeout,
 198	.get = param_get_int,
 199};
 200#define param_check_timeout param_check_int
 201
 202typedef int (*action_fn)(const char *intval, char *outval);
 203
 204static int action_op(const char *inval, char *outval);
 205static int preaction_op(const char *inval, char *outval);
 206static int preop_op(const char *inval, char *outval);
 207static void check_parms(void);
 208
 209static int set_param_str(const char *val, const struct kernel_param *kp)
 210{
 211	action_fn  fn = (action_fn) kp->arg;
 212	int        rv = 0;
 213	char       valcp[16];
 214	char       *s;
 215
 216	strscpy(valcp, val, 16);
 217
 218	s = strstrip(valcp);
 219
 220	rv = fn(s, NULL);
 221	if (rv)
 222		goto out;
 223
 224	check_parms();
 225	if (watchdog_user)
 226		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 227
 228 out:
 229	return rv;
 230}
 231
 232static int get_param_str(char *buffer, const struct kernel_param *kp)
 233{
 234	action_fn fn = (action_fn) kp->arg;
 235	int rv, len;
 236
 237	rv = fn(NULL, buffer);
 238	if (rv)
 239		return rv;
 240
 241	len = strlen(buffer);
 242	buffer[len++] = '\n';
 243	buffer[len] = 0;
 244
 245	return len;
 246}
 247
 248
 249static int set_param_wdog_ifnum(const char *val, const struct kernel_param *kp)
 250{
 251	int rv = param_set_int(val, kp);
 252	if (rv)
 253		return rv;
 254	if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
 255		return 0;
 256
 257	ipmi_unregister_watchdog(watchdog_ifnum);
 258	ipmi_register_watchdog(ifnum_to_use);
 259	return 0;
 260}
 261
 262static const struct kernel_param_ops param_ops_wdog_ifnum = {
 263	.set = set_param_wdog_ifnum,
 264	.get = param_get_int,
 265};
 266
 267#define param_check_wdog_ifnum param_check_int
 268
 269static const struct kernel_param_ops param_ops_str = {
 270	.set = set_param_str,
 271	.get = get_param_str,
 272};
 273
 274module_param(ifnum_to_use, wdog_ifnum, 0644);
 275MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
 276		 "timer.  Setting to -1 defaults to the first registered "
 277		 "interface");
 278
 279module_param(timeout, timeout, 0644);
 280MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
 281
 282module_param(pretimeout, timeout, 0644);
 283MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
 284
 285module_param(panic_wdt_timeout, timeout, 0644);
 286MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
 287
 288module_param_cb(action, &param_ops_str, action_op, 0644);
 289MODULE_PARM_DESC(action, "Timeout action. One of: "
 290		 "reset, none, power_cycle, power_off.");
 291
 292module_param_cb(preaction, &param_ops_str, preaction_op, 0644);
 293MODULE_PARM_DESC(preaction, "Pretimeout action.  One of: "
 294		 "pre_none, pre_smi, pre_nmi, pre_int.");
 295
 296module_param_cb(preop, &param_ops_str, preop_op, 0644);
 297MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
 298		 "preop_none, preop_panic, preop_give_data.");
 299
 300module_param(start_now, int, 0444);
 301MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
 302		 "soon as the driver is loaded.");
 303
 304module_param(nowayout, bool, 0644);
 305MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 306		 "(default=CONFIG_WATCHDOG_NOWAYOUT)");
 307
 308/* Default state of the timer. */
 309static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
 310
 311/* Is someone using the watchdog?  Only one user is allowed. */
 312static unsigned long ipmi_wdog_open;
 313
 314/*
 315 * If set to 1, the heartbeat command will set the state to reset and
 316 * start the timer.  The timer doesn't normally run when the driver is
 317 * first opened until the heartbeat is set the first time, this
 318 * variable is used to accomplish this.
 319 */
 320static int ipmi_start_timer_on_heartbeat;
 321
 322/* IPMI version of the BMC. */
 323static unsigned char ipmi_version_major;
 324static unsigned char ipmi_version_minor;
 325
 326/* If a pretimeout occurs, this is used to allow only one panic to happen. */
 327static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
 328
 329#ifdef HAVE_DIE_NMI
 330static int testing_nmi;
 331static int nmi_handler_registered;
 332#endif
 333
 334static int __ipmi_heartbeat(void);
 335
 336/*
 337 * We use a mutex to make sure that only one thing can send a set a
 338 * message at one time.  The mutex is claimed when a message is sent
 339 * and freed when both the send and receive messages are free.
 340 */
 341static atomic_t msg_tofree = ATOMIC_INIT(0);
 342static DECLARE_COMPLETION(msg_wait);
 343static void msg_free_smi(struct ipmi_smi_msg *msg)
 344{
 345	if (atomic_dec_and_test(&msg_tofree)) {
 346		if (!oops_in_progress)
 347			complete(&msg_wait);
 348	}
 349}
 350static void msg_free_recv(struct ipmi_recv_msg *msg)
 351{
 352	if (atomic_dec_and_test(&msg_tofree)) {
 353		if (!oops_in_progress)
 354			complete(&msg_wait);
 355	}
 356}
 357static struct ipmi_smi_msg smi_msg = INIT_IPMI_SMI_MSG(msg_free_smi);
 358static struct ipmi_recv_msg recv_msg = INIT_IPMI_RECV_MSG(msg_free_recv);
 359
 360static int __ipmi_set_timeout(struct ipmi_smi_msg  *smi_msg,
 361			      struct ipmi_recv_msg *recv_msg,
 362			      int                  *send_heartbeat_now)
 363{
 364	struct kernel_ipmi_msg            msg;
 365	unsigned char                     data[6];
 366	int                               rv = 0;
 367	struct ipmi_system_interface_addr addr;
 368	int                               hbnow = 0;
 369
 370
 371	data[0] = 0;
 372	WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
 373
 374	if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
 375		if ((ipmi_version_major > 1) ||
 376		    ((ipmi_version_major == 1) && (ipmi_version_minor >= 5))) {
 377			/* This is an IPMI 1.5-only feature. */
 378			data[0] |= WDOG_DONT_STOP_ON_SET;
 379		} else {
 380			/*
 381			 * In ipmi 1.0, setting the timer stops the watchdog, we
 382			 * need to start it back up again.
 383			 */
 384			hbnow = 1;
 385		}
 386	}
 387
 388	data[1] = 0;
 389	WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
 390	if ((pretimeout > 0) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
 391	    WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
 392	    data[2] = pretimeout;
 393	} else {
 394	    WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
 395	    data[2] = 0; /* No pretimeout. */
 396	}
 397	data[3] = 0;
 398	WDOG_SET_TIMEOUT(data[4], data[5], timeout);
 399
 400	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
 401	addr.channel = IPMI_BMC_CHANNEL;
 402	addr.lun = 0;
 403
 404	msg.netfn = 0x06;
 405	msg.cmd = IPMI_WDOG_SET_TIMER;
 406	msg.data = data;
 407	msg.data_len = sizeof(data);
 408	if (smi_msg)
 409		rv = ipmi_request_supply_msgs(watchdog_user,
 410					      (struct ipmi_addr *) &addr,
 411					      0,
 412					      &msg,
 413					      NULL,
 414					      smi_msg,
 415					      recv_msg,
 416					      1);
 417	else
 418		ipmi_panic_request_and_wait(watchdog_user,
 419					    (struct ipmi_addr *) &addr, &msg);
 420	if (rv)
 421		pr_warn("set timeout error: %d\n", rv);
 422	else if (send_heartbeat_now)
 423		*send_heartbeat_now = hbnow;
 424
 425	return rv;
 426}
 427
 428static int _ipmi_set_timeout(int do_heartbeat)
 429{
 430	int send_heartbeat_now;
 431	int rv;
 432
 433	if (!watchdog_user)
 434		return -ENODEV;
 435
 436	atomic_set(&msg_tofree, 2);
 437
 438	rv = __ipmi_set_timeout(&smi_msg, &recv_msg, &send_heartbeat_now);
 439	if (rv) {
 440		atomic_set(&msg_tofree, 0);
 441		return rv;
 442	}
 443
 444	wait_for_completion(&msg_wait);
 445
 446	if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
 447		|| ((send_heartbeat_now)
 448		    && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
 449		rv = __ipmi_heartbeat();
 450
 451	return rv;
 452}
 453
 454static int ipmi_set_timeout(int do_heartbeat)
 455{
 456	int rv;
 457
 458	mutex_lock(&ipmi_watchdog_mutex);
 459	rv = _ipmi_set_timeout(do_heartbeat);
 460	mutex_unlock(&ipmi_watchdog_mutex);
 461
 462	return rv;
 463}
 464
 465static void panic_halt_ipmi_heartbeat(void)
 466{
 467	struct kernel_ipmi_msg             msg;
 468	struct ipmi_system_interface_addr addr;
 469
 470	/*
 471	 * Don't reset the timer if we have the timer turned off, that
 472	 * re-enables the watchdog.
 473	 */
 474	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
 475		return;
 476
 477	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
 478	addr.channel = IPMI_BMC_CHANNEL;
 479	addr.lun = 0;
 480
 481	msg.netfn = 0x06;
 482	msg.cmd = IPMI_WDOG_RESET_TIMER;
 483	msg.data = NULL;
 484	msg.data_len = 0;
 485	ipmi_panic_request_and_wait(watchdog_user, (struct ipmi_addr *) &addr,
 486				    &msg);
 487}
 488
 489/*
 490 * Special call, doesn't claim any locks.  This is only to be called
 491 * at panic or halt time, in run-to-completion mode, when the caller
 492 * is the only CPU and the only thing that will be going is these IPMI
 493 * calls.
 494 */
 495static void panic_halt_ipmi_set_timeout(void)
 496{
 497	int send_heartbeat_now;
 498	int rv;
 499
 500	rv = __ipmi_set_timeout(NULL, NULL, &send_heartbeat_now);
 501	if (rv) {
 502		pr_warn("Unable to extend the watchdog timeout\n");
 503	} else {
 504		if (send_heartbeat_now)
 505			panic_halt_ipmi_heartbeat();
 506	}
 507}
 508
 509static int __ipmi_heartbeat(void)
 510{
 511	struct kernel_ipmi_msg msg;
 512	int rv;
 513	struct ipmi_system_interface_addr addr;
 514	int timeout_retries = 0;
 515
 516restart:
 517	/*
 518	 * Don't reset the timer if we have the timer turned off, that
 519	 * re-enables the watchdog.
 520	 */
 521	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
 522		return 0;
 523
 524	atomic_set(&msg_tofree, 2);
 525
 526	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
 527	addr.channel = IPMI_BMC_CHANNEL;
 528	addr.lun = 0;
 529
 530	msg.netfn = 0x06;
 531	msg.cmd = IPMI_WDOG_RESET_TIMER;
 532	msg.data = NULL;
 533	msg.data_len = 0;
 534	rv = ipmi_request_supply_msgs(watchdog_user,
 535				      (struct ipmi_addr *) &addr,
 536				      0,
 537				      &msg,
 538				      NULL,
 539				      &smi_msg,
 540				      &recv_msg,
 541				      1);
 542	if (rv) {
 543		atomic_set(&msg_tofree, 0);
 544		pr_warn("heartbeat send failure: %d\n", rv);
 545		return rv;
 546	}
 547
 548	/* Wait for the heartbeat to be sent. */
 549	wait_for_completion(&msg_wait);
 550
 551	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
 552		timeout_retries++;
 553		if (timeout_retries > 3) {
 554			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
 555			rv = -EIO;
 556			goto out;
 557		}
 558
 559		/*
 560		 * The timer was not initialized, that means the BMC was
 561		 * probably reset and lost the watchdog information.  Attempt
 562		 * to restore the timer's info.  Note that we still hold
 563		 * the heartbeat lock, to keep a heartbeat from happening
 564		 * in this process, so must say no heartbeat to avoid a
 565		 * deadlock on this mutex
 566		 */
 567		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
 568		if (rv) {
 569			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
 570			goto out;
 571		}
 572
 573		/* Might need a heartbeat send, go ahead and do it. */
 574		goto restart;
 575	} else if (recv_msg.msg.data[0] != 0) {
 576		/*
 577		 * Got an error in the heartbeat response.  It was already
 578		 * reported in ipmi_wdog_msg_handler, but we should return
 579		 * an error here.
 580		 */
 581		rv = -EINVAL;
 582	}
 583
 584out:
 585	return rv;
 586}
 587
 588static int _ipmi_heartbeat(void)
 589{
 590	int rv;
 591
 592	if (!watchdog_user)
 593		return -ENODEV;
 594
 595	if (ipmi_start_timer_on_heartbeat) {
 596		ipmi_start_timer_on_heartbeat = 0;
 597		ipmi_watchdog_state = action_val;
 598		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
 599	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
 600		/*
 601		 * A pretimeout occurred, make sure we set the timeout.
 602		 * We don't want to set the action, though, we want to
 603		 * leave that alone (thus it can't be combined with the
 604		 * above operation.
 605		 */
 606		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 607	} else {
 608		rv = __ipmi_heartbeat();
 609	}
 610
 611	return rv;
 612}
 613
 614static int ipmi_heartbeat(void)
 615{
 616	int rv;
 617
 618	mutex_lock(&ipmi_watchdog_mutex);
 619	rv = _ipmi_heartbeat();
 620	mutex_unlock(&ipmi_watchdog_mutex);
 621
 622	return rv;
 623}
 624
 625static const struct watchdog_info ident = {
 626	.options	= 0,	/* WDIOF_SETTIMEOUT, */
 627	.firmware_version = 1,
 628	.identity	= "IPMI"
 629};
 630
 631static int ipmi_ioctl(struct file *file,
 632		      unsigned int cmd, unsigned long arg)
 633{
 634	void __user *argp = (void __user *)arg;
 635	int i;
 636	int val;
 637
 638	switch (cmd) {
 639	case WDIOC_GETSUPPORT:
 640		i = copy_to_user(argp, &ident, sizeof(ident));
 641		return i ? -EFAULT : 0;
 642
 643	case WDIOC_SETTIMEOUT:
 644		i = copy_from_user(&val, argp, sizeof(int));
 645		if (i)
 646			return -EFAULT;
 647		timeout = val;
 648		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 649
 650	case WDIOC_GETTIMEOUT:
 651		i = copy_to_user(argp, &timeout, sizeof(timeout));
 652		if (i)
 653			return -EFAULT;
 654		return 0;
 655
 656	case WDIOC_SETPRETIMEOUT:
 657		i = copy_from_user(&val, argp, sizeof(int));
 658		if (i)
 659			return -EFAULT;
 660		pretimeout = val;
 661		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 662
 663	case WDIOC_GETPRETIMEOUT:
 664		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
 665		if (i)
 666			return -EFAULT;
 667		return 0;
 668
 669	case WDIOC_KEEPALIVE:
 670		return _ipmi_heartbeat();
 671
 672	case WDIOC_SETOPTIONS:
 673		i = copy_from_user(&val, argp, sizeof(int));
 674		if (i)
 675			return -EFAULT;
 676		if (val & WDIOS_DISABLECARD) {
 677			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
 678			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
 679			ipmi_start_timer_on_heartbeat = 0;
 680		}
 681
 682		if (val & WDIOS_ENABLECARD) {
 683			ipmi_watchdog_state = action_val;
 684			_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
 685		}
 686		return 0;
 687
 688	case WDIOC_GETSTATUS:
 689		val = 0;
 690		i = copy_to_user(argp, &val, sizeof(val));
 691		if (i)
 692			return -EFAULT;
 693		return 0;
 694
 695	default:
 696		return -ENOIOCTLCMD;
 697	}
 698}
 699
 700static long ipmi_unlocked_ioctl(struct file *file,
 701				unsigned int cmd,
 702				unsigned long arg)
 703{
 704	int ret;
 705
 706	mutex_lock(&ipmi_watchdog_mutex);
 707	ret = ipmi_ioctl(file, cmd, arg);
 708	mutex_unlock(&ipmi_watchdog_mutex);
 709
 710	return ret;
 711}
 712
 713static ssize_t ipmi_write(struct file *file,
 714			  const char  __user *buf,
 715			  size_t      len,
 716			  loff_t      *ppos)
 717{
 718	int rv;
 719
 720	if (len) {
 721		if (!nowayout) {
 722			size_t i;
 723
 724			/* In case it was set long ago */
 725			expect_close = 0;
 726
 727			for (i = 0; i != len; i++) {
 728				char c;
 729
 730				if (get_user(c, buf + i))
 731					return -EFAULT;
 732				if (c == 'V')
 733					expect_close = 42;
 734			}
 735		}
 736		rv = ipmi_heartbeat();
 737		if (rv)
 738			return rv;
 739	}
 740	return len;
 741}
 742
 743static ssize_t ipmi_read(struct file *file,
 744			 char        __user *buf,
 745			 size_t      count,
 746			 loff_t      *ppos)
 747{
 748	int          rv = 0;
 749	wait_queue_entry_t wait;
 750
 751	if (count <= 0)
 752		return 0;
 753
 754	/*
 755	 * Reading returns if the pretimeout has gone off, and it only does
 756	 * it once per pretimeout.
 757	 */
 758	mutex_lock(&ipmi_read_mutex);
 759	if (!data_to_read) {
 760		if (file->f_flags & O_NONBLOCK) {
 761			rv = -EAGAIN;
 762			goto out;
 763		}
 764
 765		init_waitqueue_entry(&wait, current);
 766		add_wait_queue(&read_q, &wait);
 767		while (!data_to_read && !signal_pending(current)) {
 768			set_current_state(TASK_INTERRUPTIBLE);
 769			mutex_unlock(&ipmi_read_mutex);
 770			schedule();
 771			mutex_lock(&ipmi_read_mutex);
 772		}
 773		remove_wait_queue(&read_q, &wait);
 774
 775		if (signal_pending(current)) {
 776			rv = -ERESTARTSYS;
 777			goto out;
 778		}
 779	}
 780	data_to_read = 0;
 781
 782 out:
 783	mutex_unlock(&ipmi_read_mutex);
 784
 785	if (rv == 0) {
 786		if (copy_to_user(buf, &data_to_read, 1))
 787			rv = -EFAULT;
 788		else
 789			rv = 1;
 790	}
 791
 792	return rv;
 793}
 794
 795static int ipmi_open(struct inode *ino, struct file *filep)
 796{
 797	switch (iminor(ino)) {
 798	case WATCHDOG_MINOR:
 799		if (test_and_set_bit(0, &ipmi_wdog_open))
 800			return -EBUSY;
 801
 802
 803		/*
 804		 * Don't start the timer now, let it start on the
 805		 * first heartbeat.
 806		 */
 807		ipmi_start_timer_on_heartbeat = 1;
 808		return stream_open(ino, filep);
 809
 810	default:
 811		return (-ENODEV);
 812	}
 813}
 814
 815static __poll_t ipmi_poll(struct file *file, poll_table *wait)
 816{
 817	__poll_t mask = 0;
 818
 819	poll_wait(file, &read_q, wait);
 820
 821	mutex_lock(&ipmi_read_mutex);
 822	if (data_to_read)
 823		mask |= (EPOLLIN | EPOLLRDNORM);
 824	mutex_unlock(&ipmi_read_mutex);
 825
 826	return mask;
 827}
 828
 829static int ipmi_fasync(int fd, struct file *file, int on)
 830{
 831	int result;
 832
 833	result = fasync_helper(fd, file, on, &fasync_q);
 834
 835	return (result);
 836}
 837
 838static int ipmi_close(struct inode *ino, struct file *filep)
 839{
 840	if (iminor(ino) == WATCHDOG_MINOR) {
 841		if (expect_close == 42) {
 842			mutex_lock(&ipmi_watchdog_mutex);
 843			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
 844			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
 845			mutex_unlock(&ipmi_watchdog_mutex);
 846		} else {
 847			pr_crit("Unexpected close, not stopping watchdog!\n");
 848			ipmi_heartbeat();
 849		}
 850		clear_bit(0, &ipmi_wdog_open);
 851	}
 852
 853	expect_close = 0;
 854
 855	return 0;
 856}
 857
 858static const struct file_operations ipmi_wdog_fops = {
 859	.owner   = THIS_MODULE,
 860	.read    = ipmi_read,
 861	.poll    = ipmi_poll,
 862	.write   = ipmi_write,
 863	.unlocked_ioctl = ipmi_unlocked_ioctl,
 864	.compat_ioctl	= compat_ptr_ioctl,
 865	.open    = ipmi_open,
 866	.release = ipmi_close,
 867	.fasync  = ipmi_fasync,
 868};
 869
 870static struct miscdevice ipmi_wdog_miscdev = {
 871	.minor		= WATCHDOG_MINOR,
 872	.name		= "watchdog",
 873	.fops		= &ipmi_wdog_fops
 874};
 875
 876static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
 877				  void                 *handler_data)
 878{
 879	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
 880			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
 881		pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
 882	else if (msg->msg.data[0] != 0)
 883		pr_err("response: Error %x on cmd %x\n",
 884		       msg->msg.data[0],
 885		       msg->msg.cmd);
 886
 887	ipmi_free_recv_msg(msg);
 888}
 889
 890static void ipmi_wdog_pretimeout_handler(void *handler_data)
 891{
 892	if (preaction_val != WDOG_PRETIMEOUT_NONE) {
 893		if (preop_val == WDOG_PREOP_PANIC) {
 894			if (atomic_inc_and_test(&preop_panic_excl))
 895				panic("Watchdog pre-timeout");
 896		} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
 897			mutex_lock(&ipmi_read_mutex);
 898			data_to_read = 1;
 899			wake_up_interruptible(&read_q);
 900			kill_fasync(&fasync_q, SIGIO, POLL_IN);
 901			mutex_unlock(&ipmi_read_mutex);
 902		}
 903	}
 904
 905	/*
 906	 * On some machines, the heartbeat will give an error and not
 907	 * work unless we re-enable the timer.  So do so.
 908	 */
 909	atomic_set(&pretimeout_since_last_heartbeat, 1);
 910}
 911
 912static void ipmi_wdog_panic_handler(void *user_data)
 913{
 914	static int panic_event_handled;
 915
 916	/*
 917	 * On a panic, if we have a panic timeout, make sure to extend
 918	 * the watchdog timer to a reasonable value to complete the
 919	 * panic, if the watchdog timer is running.  Plus the
 920	 * pretimeout is meaningless at panic time.
 921	 */
 922	if (watchdog_user && !panic_event_handled &&
 923	    ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
 924		/* Make sure we do this only once. */
 925		panic_event_handled = 1;
 926
 927		timeout = panic_wdt_timeout;
 928		pretimeout = 0;
 929		panic_halt_ipmi_set_timeout();
 930	}
 931}
 932
 933static const struct ipmi_user_hndl ipmi_hndlrs = {
 934	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
 935	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
 936	.ipmi_panic_handler       = ipmi_wdog_panic_handler
 937};
 938
 939static void ipmi_register_watchdog(int ipmi_intf)
 940{
 941	int rv = -EBUSY;
 942
 943	if (watchdog_user)
 944		goto out;
 945
 946	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
 947		goto out;
 948
 949	watchdog_ifnum = ipmi_intf;
 950
 951	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
 952	if (rv < 0) {
 953		pr_crit("Unable to register with ipmi\n");
 954		goto out;
 955	}
 956
 957	rv = ipmi_get_version(watchdog_user,
 958			      &ipmi_version_major,
 959			      &ipmi_version_minor);
 960	if (rv) {
 961		pr_warn("Unable to get IPMI version, assuming 1.0\n");
 962		ipmi_version_major = 1;
 963		ipmi_version_minor = 0;
 964	}
 965
 966	rv = misc_register(&ipmi_wdog_miscdev);
 967	if (rv < 0) {
 968		ipmi_destroy_user(watchdog_user);
 969		watchdog_user = NULL;
 970		pr_crit("Unable to register misc device\n");
 971	}
 972
 973#ifdef HAVE_DIE_NMI
 974	if (nmi_handler_registered) {
 975		int old_pretimeout = pretimeout;
 976		int old_timeout = timeout;
 977		int old_preop_val = preop_val;
 978
 979		/*
 980		 * Set the pretimeout to go off in a second and give
 981		 * ourselves plenty of time to stop the timer.
 982		 */
 983		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
 984		preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
 985		pretimeout = 99;
 986		timeout = 100;
 987
 988		testing_nmi = 1;
 989
 990		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
 991		if (rv) {
 992			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",
 993				rv);
 994			rv = 0;
 995			goto out_restore;
 996		}
 997
 998		msleep(1500);
 999
1000		if (testing_nmi != 2) {
1001			pr_warn("IPMI NMI didn't seem to occur.  The NMI pretimeout will likely not work\n");
1002		}
1003 out_restore:
1004		testing_nmi = 0;
1005		preop_val = old_preop_val;
1006		pretimeout = old_pretimeout;
1007		timeout = old_timeout;
1008	}
1009#endif
1010
1011 out:
1012	if ((start_now) && (rv == 0)) {
1013		/* Run from startup, so start the timer now. */
1014		start_now = 0; /* Disable this function after first startup. */
1015		ipmi_watchdog_state = action_val;
1016		ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1017		pr_info("Starting now!\n");
1018	} else {
1019		/* Stop the timer now. */
1020		ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1021		ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1022	}
1023}
1024
1025static void ipmi_unregister_watchdog(int ipmi_intf)
1026{
1027	struct ipmi_user *loc_user = watchdog_user;
1028
1029	if (!loc_user)
1030		return;
1031
1032	if (watchdog_ifnum != ipmi_intf)
1033		return;
1034
1035	/* Make sure no one can call us any more. */
1036	misc_deregister(&ipmi_wdog_miscdev);
1037
1038	watchdog_user = NULL;
1039
1040	/*
1041	 * Wait to make sure the message makes it out.  The lower layer has
1042	 * pointers to our buffers, we want to make sure they are done before
1043	 * we release our memory.
1044	 */
1045	while (atomic_read(&msg_tofree))
1046		msg_free_smi(NULL);
1047
1048	mutex_lock(&ipmi_watchdog_mutex);
1049
1050	/* Disconnect from IPMI. */
1051	ipmi_destroy_user(loc_user);
1052
1053	/* If it comes back, restart it properly. */
1054	ipmi_start_timer_on_heartbeat = 1;
1055
1056	mutex_unlock(&ipmi_watchdog_mutex);
1057}
1058
1059#ifdef HAVE_DIE_NMI
1060static int
1061ipmi_nmi(unsigned int val, struct pt_regs *regs)
1062{
1063	/*
1064	 * If we get here, it's an NMI that's not a memory or I/O
1065	 * error.  We can't truly tell if it's from IPMI or not
1066	 * without sending a message, and sending a message is almost
1067	 * impossible because of locking.
1068	 */
1069
1070	if (testing_nmi) {
1071		testing_nmi = 2;
1072		return NMI_HANDLED;
1073	}
1074
1075	/* If we are not expecting a timeout, ignore it. */
1076	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
1077		return NMI_DONE;
1078
1079	if (preaction_val != WDOG_PRETIMEOUT_NMI)
1080		return NMI_DONE;
1081
1082	/*
1083	 * If no one else handled the NMI, we assume it was the IPMI
1084	 * watchdog.
1085	 */
1086	if (preop_val == WDOG_PREOP_PANIC) {
1087		/* On some machines, the heartbeat will give
1088		   an error and not work unless we re-enable
1089		   the timer.   So do so. */
1090		atomic_set(&pretimeout_since_last_heartbeat, 1);
1091		if (atomic_inc_and_test(&preop_panic_excl))
1092			nmi_panic(regs, "pre-timeout");
1093	}
1094
1095	return NMI_HANDLED;
1096}
1097#endif
1098
1099static int wdog_reboot_handler(struct notifier_block *this,
1100			       unsigned long         code,
1101			       void                  *unused)
1102{
1103	static int reboot_event_handled;
1104
1105	if ((watchdog_user) && (!reboot_event_handled)) {
1106		/* Make sure we only do this once. */
1107		reboot_event_handled = 1;
1108
1109		if (code == SYS_POWER_OFF || code == SYS_HALT) {
1110			/* Disable the WDT if we are shutting down. */
1111			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1112			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1113		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
1114			/* Set a long timer to let the reboot happen or
1115			   reset if it hangs, but only if the watchdog
1116			   timer was already running. */
1117			if (timeout < 120)
1118				timeout = 120;
1119			pretimeout = 0;
1120			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1121			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1122		}
1123	}
1124	return NOTIFY_OK;
1125}
1126
1127static struct notifier_block wdog_reboot_notifier = {
1128	.notifier_call	= wdog_reboot_handler,
1129	.next		= NULL,
1130	.priority	= 0
1131};
1132
1133static void ipmi_new_smi(int if_num, struct device *device)
1134{
1135	ipmi_register_watchdog(if_num);
1136}
1137
1138static void ipmi_smi_gone(int if_num)
1139{
1140	ipmi_unregister_watchdog(if_num);
1141}
1142
1143static struct ipmi_smi_watcher smi_watcher = {
1144	.owner    = THIS_MODULE,
1145	.new_smi  = ipmi_new_smi,
1146	.smi_gone = ipmi_smi_gone
1147};
1148
1149static int action_op_set_val(const char *inval)
1150{
1151	if (strcmp(inval, "reset") == 0)
1152		action_val = WDOG_TIMEOUT_RESET;
1153	else if (strcmp(inval, "none") == 0)
1154		action_val = WDOG_TIMEOUT_NONE;
1155	else if (strcmp(inval, "power_cycle") == 0)
1156		action_val = WDOG_TIMEOUT_POWER_CYCLE;
1157	else if (strcmp(inval, "power_off") == 0)
1158		action_val = WDOG_TIMEOUT_POWER_DOWN;
1159	else
1160		return -EINVAL;
1161	return 0;
1162}
1163
1164static int action_op(const char *inval, char *outval)
1165{
1166	int rv;
1167
1168	if (outval)
1169		strcpy(outval, action);
1170
1171	if (!inval)
1172		return 0;
1173	rv = action_op_set_val(inval);
1174	if (!rv)
1175		strcpy(action, inval);
1176	return rv;
1177}
1178
1179static int preaction_op_set_val(const char *inval)
1180{
1181	if (strcmp(inval, "pre_none") == 0)
1182		preaction_val = WDOG_PRETIMEOUT_NONE;
1183	else if (strcmp(inval, "pre_smi") == 0)
1184		preaction_val = WDOG_PRETIMEOUT_SMI;
1185#ifdef HAVE_DIE_NMI
1186	else if (strcmp(inval, "pre_nmi") == 0)
1187		preaction_val = WDOG_PRETIMEOUT_NMI;
1188#endif
1189	else if (strcmp(inval, "pre_int") == 0)
1190		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
1191	else
1192		return -EINVAL;
1193	return 0;
1194}
1195
1196static int preaction_op(const char *inval, char *outval)
1197{
1198	int rv;
1199
1200	if (outval)
1201		strcpy(outval, preaction);
1202
1203	if (!inval)
1204		return 0;
1205	rv = preaction_op_set_val(inval);
1206	if (!rv)
1207		strcpy(preaction, inval);
1208	return 0;
1209}
1210
1211static int preop_op_set_val(const char *inval)
1212{
1213	if (strcmp(inval, "preop_none") == 0)
1214		preop_val = WDOG_PREOP_NONE;
1215	else if (strcmp(inval, "preop_panic") == 0)
1216		preop_val = WDOG_PREOP_PANIC;
1217	else if (strcmp(inval, "preop_give_data") == 0)
1218		preop_val = WDOG_PREOP_GIVE_DATA;
1219	else
1220		return -EINVAL;
1221	return 0;
1222}
1223
1224static int preop_op(const char *inval, char *outval)
1225{
1226	int rv;
1227
1228	if (outval)
1229		strcpy(outval, preop);
1230
1231	if (!inval)
1232		return 0;
1233
1234	rv = preop_op_set_val(inval);
1235	if (!rv)
1236		strcpy(preop, inval);
1237	return 0;
1238}
1239
1240static void check_parms(void)
1241{
1242#ifdef HAVE_DIE_NMI
1243	int do_nmi = 0;
1244	int rv;
1245
1246	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
1247		do_nmi = 1;
1248		if (preop_val == WDOG_PREOP_GIVE_DATA) {
1249			pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
1250			preop_op("preop_none", NULL);
1251			do_nmi = 0;
1252		}
1253	}
1254	if (do_nmi && !nmi_handler_registered) {
1255		rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
1256						"ipmi");
1257		if (rv) {
1258			pr_warn("Can't register nmi handler\n");
1259			return;
1260		} else
1261			nmi_handler_registered = 1;
1262	} else if (!do_nmi && nmi_handler_registered) {
1263		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1264		nmi_handler_registered = 0;
1265	}
1266#endif
1267}
1268
1269static int __init ipmi_wdog_init(void)
1270{
1271	int rv;
1272
1273	if (action_op_set_val(action)) {
1274		action_op("reset", NULL);
1275		pr_info("Unknown action '%s', defaulting to reset\n", action);
1276	}
1277
1278	if (preaction_op_set_val(preaction)) {
1279		preaction_op("pre_none", NULL);
1280		pr_info("Unknown preaction '%s', defaulting to none\n",
1281			preaction);
1282	}
1283
1284	if (preop_op_set_val(preop)) {
1285		preop_op("preop_none", NULL);
1286		pr_info("Unknown preop '%s', defaulting to none\n", preop);
1287	}
1288
1289	check_parms();
1290
1291	register_reboot_notifier(&wdog_reboot_notifier);
1292
1293	rv = ipmi_smi_watcher_register(&smi_watcher);
1294	if (rv) {
1295#ifdef HAVE_DIE_NMI
1296		if (nmi_handler_registered)
1297			unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1298#endif
1299		unregister_reboot_notifier(&wdog_reboot_notifier);
1300		pr_warn("can't register smi watcher\n");
1301		return rv;
1302	}
1303
1304	pr_info("driver initialized\n");
1305
1306	return 0;
1307}
1308
1309static void __exit ipmi_wdog_exit(void)
1310{
1311	ipmi_smi_watcher_unregister(&smi_watcher);
1312	ipmi_unregister_watchdog(watchdog_ifnum);
1313
1314#ifdef HAVE_DIE_NMI
1315	if (nmi_handler_registered)
1316		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1317#endif
1318
1319	unregister_reboot_notifier(&wdog_reboot_notifier);
1320}
1321module_exit(ipmi_wdog_exit);
1322module_init(ipmi_wdog_init);
1323MODULE_LICENSE("GPL");
1324MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
1325MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");