1 /* 2 * HP WatchDog Driver 3 * based on 4 * 5 * SoftDog 0.05: A Software Watchdog Device 6 * 7 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P. 8 * Thomas Mingarelli <thomas.mingarelli@hp.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * version 2 as published by the Free Software Foundation 13 * 14 */ 15 16 #include <linux/device.h> 17 #include <linux/fs.h> 18 #include <linux/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/io.h> 21 #include <linux/irq.h> 22 #include <linux/kernel.h> 23 #include <linux/miscdevice.h> 24 #include <linux/mm.h> 25 #include <linux/module.h> 26 #include <linux/kdebug.h> 27 #include <linux/moduleparam.h> 28 #include <linux/notifier.h> 29 #include <linux/pci.h> 30 #include <linux/pci_ids.h> 31 #include <linux/reboot.h> 32 #include <linux/sched.h> 33 #include <linux/timer.h> 34 #include <linux/types.h> 35 #include <linux/uaccess.h> 36 #include <linux/watchdog.h> 37 #include <linux/dmi.h> 38 #include <linux/efi.h> 39 #include <linux/string.h> 40 #include <linux/bootmem.h> 41 #include <linux/slab.h> 42 #include <asm/desc.h> 43 #include <asm/cacheflush.h> 44 45 #define PCI_BIOS32_SD_VALUE 0x5F32335F /* "_32_" */ 46 #define CRU_BIOS_SIGNATURE_VALUE 0x55524324 47 #define PCI_BIOS32_PARAGRAPH_LEN 16 48 #define PCI_ROM_BASE1 0x000F0000 49 #define ROM_SIZE 0x10000 50 #define HPWDT_VERSION "1.01" 51 52 struct bios32_service_dir { 53 u32 signature; 54 u32 entry_point; 55 u8 revision; 56 u8 length; 57 u8 checksum; 58 u8 reserved[5]; 59 }; 60 61 /* type 212 */ 62 struct smbios_cru64_info { 63 u8 type; 64 u8 byte_length; 65 u16 handle; 66 u32 signature; 67 u64 physical_address; 68 u32 double_length; 69 u32 double_offset; 70 }; 71 #define SMBIOS_CRU64_INFORMATION 212 72 73 struct cmn_registers { 74 union { 75 struct { 76 u8 ral; 77 u8 rah; 78 u16 rea2; 79 }; 80 u32 reax; 81 } u1; 82 union { 83 struct { 84 u8 rbl; 85 u8 rbh; 86 u8 reb2l; 87 u8 reb2h; 88 }; 89 u32 rebx; 90 } u2; 91 union { 92 struct { 93 u8 rcl; 94 u8 rch; 95 u16 rec2; 96 }; 97 u32 recx; 98 } u3; 99 union { 100 struct { 101 u8 rdl; 102 u8 rdh; 103 u16 red2; 104 }; 105 u32 redx; 106 } u4; 107 108 u32 resi; 109 u32 redi; 110 u16 rds; 111 u16 res; 112 u32 reflags; 113 } __attribute__((packed)); 114 115 #define DEFAULT_MARGIN 30 116 static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */ 117 static unsigned int reload; /* the computed soft_margin */ 118 static int nowayout = WATCHDOG_NOWAYOUT; 119 static char expect_release; 120 static unsigned long hpwdt_is_open; 121 static unsigned int allow_kdump; 122 123 static void __iomem *pci_mem_addr; /* the PCI-memory address */ 124 static unsigned long __iomem *hpwdt_timer_reg; 125 static unsigned long __iomem *hpwdt_timer_con; 126 127 static DEFINE_SPINLOCK(rom_lock); 128 129 static void *cru_rom_addr; 130 131 static struct cmn_registers cmn_regs; 132 133 static struct pci_device_id hpwdt_devices[] = { 134 { PCI_DEVICE(PCI_VENDOR_ID_COMPAQ, 0xB203) }, 135 { PCI_DEVICE(PCI_VENDOR_ID_HP, 0x3306) }, 136 {0}, /* terminate list */ 137 }; 138 MODULE_DEVICE_TABLE(pci, hpwdt_devices); 139 140 extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs, 141 unsigned long *pRomEntry); 142 143 #ifndef CONFIG_X86_64 144 /* --32 Bit Bios------------------------------------------------------------ */ 145 146 #define HPWDT_ARCH 32 147 148 asm(".text \n\t" 149 ".align 4 \n" 150 "asminline_call: \n\t" 151 "pushl %ebp \n\t" 152 "movl %esp, %ebp \n\t" 153 "pusha \n\t" 154 "pushf \n\t" 155 "push %es \n\t" 156 "push %ds \n\t" 157 "pop %es \n\t" 158 "movl 8(%ebp),%eax \n\t" 159 "movl 4(%eax),%ebx \n\t" 160 "movl 8(%eax),%ecx \n\t" 161 "movl 12(%eax),%edx \n\t" 162 "movl 16(%eax),%esi \n\t" 163 "movl 20(%eax),%edi \n\t" 164 "movl (%eax),%eax \n\t" 165 "push %cs \n\t" 166 "call *12(%ebp) \n\t" 167 "pushf \n\t" 168 "pushl %eax \n\t" 169 "movl 8(%ebp),%eax \n\t" 170 "movl %ebx,4(%eax) \n\t" 171 "movl %ecx,8(%eax) \n\t" 172 "movl %edx,12(%eax) \n\t" 173 "movl %esi,16(%eax) \n\t" 174 "movl %edi,20(%eax) \n\t" 175 "movw %ds,24(%eax) \n\t" 176 "movw %es,26(%eax) \n\t" 177 "popl %ebx \n\t" 178 "movl %ebx,(%eax) \n\t" 179 "popl %ebx \n\t" 180 "movl %ebx,28(%eax) \n\t" 181 "pop %es \n\t" 182 "popf \n\t" 183 "popa \n\t" 184 "leave \n\t" 185 "ret \n\t" 186 ".previous"); 187 188 189 /* 190 * cru_detect 191 * 192 * Routine Description: 193 * This function uses the 32-bit BIOS Service Directory record to 194 * search for a $CRU record. 195 * 196 * Return Value: 197 * 0 : SUCCESS 198 * <0 : FAILURE 199 */ 200 static int __devinit cru_detect(unsigned long map_entry, 201 unsigned long map_offset) 202 { 203 void *bios32_map; 204 unsigned long *bios32_entrypoint; 205 unsigned long cru_physical_address; 206 unsigned long cru_length; 207 unsigned long physical_bios_base = 0; 208 unsigned long physical_bios_offset = 0; 209 int retval = -ENODEV; 210 211 bios32_map = ioremap(map_entry, (2 * PAGE_SIZE)); 212 213 if (bios32_map == NULL) 214 return -ENODEV; 215 216 bios32_entrypoint = bios32_map + map_offset; 217 218 cmn_regs.u1.reax = CRU_BIOS_SIGNATURE_VALUE; 219 220 asminline_call(&cmn_regs, bios32_entrypoint); 221 222 if (cmn_regs.u1.ral != 0) { 223 printk(KERN_WARNING 224 "hpwdt: Call succeeded but with an error: 0x%x\n", 225 cmn_regs.u1.ral); 226 } else { 227 physical_bios_base = cmn_regs.u2.rebx; 228 physical_bios_offset = cmn_regs.u4.redx; 229 cru_length = cmn_regs.u3.recx; 230 cru_physical_address = 231 physical_bios_base + physical_bios_offset; 232 233 /* If the values look OK, then map it in. */ 234 if ((physical_bios_base + physical_bios_offset)) { 235 cru_rom_addr = 236 ioremap(cru_physical_address, cru_length); 237 if (cru_rom_addr) 238 retval = 0; 239 } 240 241 printk(KERN_DEBUG "hpwdt: CRU Base Address: 0x%lx\n", 242 physical_bios_base); 243 printk(KERN_DEBUG "hpwdt: CRU Offset Address: 0x%lx\n", 244 physical_bios_offset); 245 printk(KERN_DEBUG "hpwdt: CRU Length: 0x%lx\n", 246 cru_length); 247 printk(KERN_DEBUG "hpwdt: CRU Mapped Address: 0x%x\n", 248 (unsigned int)&cru_rom_addr); 249 } 250 iounmap(bios32_map); 251 return retval; 252 } 253 254 /* 255 * bios_checksum 256 */ 257 static int __devinit bios_checksum(const char __iomem *ptr, int len) 258 { 259 char sum = 0; 260 int i; 261 262 /* 263 * calculate checksum of size bytes. This should add up 264 * to zero if we have a valid header. 265 */ 266 for (i = 0; i < len; i++) 267 sum += ptr[i]; 268 269 return ((sum == 0) && (len > 0)); 270 } 271 272 /* 273 * bios32_present 274 * 275 * Routine Description: 276 * This function finds the 32-bit BIOS Service Directory 277 * 278 * Return Value: 279 * 0 : SUCCESS 280 * <0 : FAILURE 281 */ 282 static int __devinit bios32_present(const char __iomem *p) 283 { 284 struct bios32_service_dir *bios_32_ptr; 285 int length; 286 unsigned long map_entry, map_offset; 287 288 bios_32_ptr = (struct bios32_service_dir *) p; 289 290 /* 291 * Search for signature by checking equal to the swizzled value 292 * instead of calling another routine to perform a strcmp. 293 */ 294 if (bios_32_ptr->signature == PCI_BIOS32_SD_VALUE) { 295 length = bios_32_ptr->length * PCI_BIOS32_PARAGRAPH_LEN; 296 if (bios_checksum(p, length)) { 297 /* 298 * According to the spec, we're looking for the 299 * first 4KB-aligned address below the entrypoint 300 * listed in the header. The Service Directory code 301 * is guaranteed to occupy no more than 2 4KB pages. 302 */ 303 map_entry = bios_32_ptr->entry_point & ~(PAGE_SIZE - 1); 304 map_offset = bios_32_ptr->entry_point - map_entry; 305 306 return cru_detect(map_entry, map_offset); 307 } 308 } 309 return -ENODEV; 310 } 311 312 static int __devinit detect_cru_service(void) 313 { 314 char __iomem *p, *q; 315 int rc = -1; 316 317 /* 318 * Search from 0x0f0000 through 0x0fffff, inclusive. 319 */ 320 p = ioremap(PCI_ROM_BASE1, ROM_SIZE); 321 if (p == NULL) 322 return -ENOMEM; 323 324 for (q = p; q < p + ROM_SIZE; q += 16) { 325 rc = bios32_present(q); 326 if (!rc) 327 break; 328 } 329 iounmap(p); 330 return rc; 331 } 332 333 #else 334 /* --64 Bit Bios------------------------------------------------------------ */ 335 336 #define HPWDT_ARCH 64 337 338 asm(".text \n\t" 339 ".align 4 \n" 340 "asminline_call: \n\t" 341 "pushq %rbp \n\t" 342 "movq %rsp, %rbp \n\t" 343 "pushq %rax \n\t" 344 "pushq %rbx \n\t" 345 "pushq %rdx \n\t" 346 "pushq %r12 \n\t" 347 "pushq %r9 \n\t" 348 "movq %rsi, %r12 \n\t" 349 "movq %rdi, %r9 \n\t" 350 "movl 4(%r9),%ebx \n\t" 351 "movl 8(%r9),%ecx \n\t" 352 "movl 12(%r9),%edx \n\t" 353 "movl 16(%r9),%esi \n\t" 354 "movl 20(%r9),%edi \n\t" 355 "movl (%r9),%eax \n\t" 356 "call *%r12 \n\t" 357 "pushfq \n\t" 358 "popq %r12 \n\t" 359 "movl %eax, (%r9) \n\t" 360 "movl %ebx, 4(%r9) \n\t" 361 "movl %ecx, 8(%r9) \n\t" 362 "movl %edx, 12(%r9) \n\t" 363 "movl %esi, 16(%r9) \n\t" 364 "movl %edi, 20(%r9) \n\t" 365 "movq %r12, %rax \n\t" 366 "movl %eax, 28(%r9) \n\t" 367 "popq %r9 \n\t" 368 "popq %r12 \n\t" 369 "popq %rdx \n\t" 370 "popq %rbx \n\t" 371 "popq %rax \n\t" 372 "leave \n\t" 373 "ret \n\t" 374 ".previous"); 375 376 /* 377 * dmi_find_cru 378 * 379 * Routine Description: 380 * This function checks whether or not a SMBIOS/DMI record is 381 * the 64bit CRU info or not 382 */ 383 static void __devinit dmi_find_cru(const struct dmi_header *dm, void *dummy) 384 { 385 struct smbios_cru64_info *smbios_cru64_ptr; 386 unsigned long cru_physical_address; 387 388 if (dm->type == SMBIOS_CRU64_INFORMATION) { 389 smbios_cru64_ptr = (struct smbios_cru64_info *) dm; 390 if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) { 391 cru_physical_address = 392 smbios_cru64_ptr->physical_address + 393 smbios_cru64_ptr->double_offset; 394 cru_rom_addr = ioremap(cru_physical_address, 395 smbios_cru64_ptr->double_length); 396 set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK, 397 smbios_cru64_ptr->double_length >> PAGE_SHIFT); 398 } 399 } 400 } 401 402 static int __devinit detect_cru_service(void) 403 { 404 cru_rom_addr = NULL; 405 406 dmi_walk(dmi_find_cru, NULL); 407 408 /* if cru_rom_addr has been set then we found a CRU service */ 409 return ((cru_rom_addr != NULL) ? 0 : -ENODEV); 410 } 411 412 /* ------------------------------------------------------------------------- */ 413 414 #endif 415 416 /* 417 * Watchdog operations 418 */ 419 static void hpwdt_start(void) 420 { 421 reload = (soft_margin * 1000) / 128; 422 iowrite16(reload, hpwdt_timer_reg); 423 iowrite16(0x85, hpwdt_timer_con); 424 } 425 426 static void hpwdt_stop(void) 427 { 428 unsigned long data; 429 430 data = ioread16(hpwdt_timer_con); 431 data &= 0xFE; 432 iowrite16(data, hpwdt_timer_con); 433 } 434 435 static void hpwdt_ping(void) 436 { 437 iowrite16(reload, hpwdt_timer_reg); 438 } 439 440 static int hpwdt_change_timer(int new_margin) 441 { 442 /* Arbitrary, can't find the card's limits */ 443 if (new_margin < 30 || new_margin > 600) { 444 printk(KERN_WARNING 445 "hpwdt: New value passed in is invalid: %d seconds.\n", 446 new_margin); 447 return -EINVAL; 448 } 449 450 soft_margin = new_margin; 451 printk(KERN_DEBUG 452 "hpwdt: New timer passed in is %d seconds.\n", 453 new_margin); 454 reload = (soft_margin * 1000) / 128; 455 456 return 0; 457 } 458 459 /* 460 * NMI Handler 461 */ 462 static int hpwdt_pretimeout(struct notifier_block *nb, unsigned long ulReason, 463 void *data) 464 { 465 unsigned long rom_pl; 466 static int die_nmi_called; 467 468 if (ulReason != DIE_NMI && ulReason != DIE_NMI_IPI) 469 return NOTIFY_OK; 470 471 spin_lock_irqsave(&rom_lock, rom_pl); 472 if (!die_nmi_called) 473 asminline_call(&cmn_regs, cru_rom_addr); 474 die_nmi_called = 1; 475 spin_unlock_irqrestore(&rom_lock, rom_pl); 476 if (cmn_regs.u1.ral == 0) { 477 printk(KERN_WARNING "hpwdt: An NMI occurred, " 478 "but unable to determine source.\n"); 479 } else { 480 if (allow_kdump) 481 hpwdt_stop(); 482 panic("An NMI occurred, please see the Integrated " 483 "Management Log for details.\n"); 484 } 485 486 return NOTIFY_OK; 487 } 488 489 /* 490 * /dev/watchdog handling 491 */ 492 static int hpwdt_open(struct inode *inode, struct file *file) 493 { 494 /* /dev/watchdog can only be opened once */ 495 if (test_and_set_bit(0, &hpwdt_is_open)) 496 return -EBUSY; 497 498 /* Start the watchdog */ 499 hpwdt_start(); 500 hpwdt_ping(); 501 502 return nonseekable_open(inode, file); 503 } 504 505 static int hpwdt_release(struct inode *inode, struct file *file) 506 { 507 /* Stop the watchdog */ 508 if (expect_release == 42) { 509 hpwdt_stop(); 510 } else { 511 printk(KERN_CRIT 512 "hpwdt: Unexpected close, not stopping watchdog!\n"); 513 hpwdt_ping(); 514 } 515 516 expect_release = 0; 517 518 /* /dev/watchdog is being closed, make sure it can be re-opened */ 519 clear_bit(0, &hpwdt_is_open); 520 521 return 0; 522 } 523 524 static ssize_t hpwdt_write(struct file *file, const char __user *data, 525 size_t len, loff_t *ppos) 526 { 527 /* See if we got the magic character 'V' and reload the timer */ 528 if (len) { 529 if (!nowayout) { 530 size_t i; 531 532 /* note: just in case someone wrote the magic character 533 * five months ago... */ 534 expect_release = 0; 535 536 /* scan to see whether or not we got the magic char. */ 537 for (i = 0; i != len; i++) { 538 char c; 539 if (get_user(c, data + i)) 540 return -EFAULT; 541 if (c == 'V') 542 expect_release = 42; 543 } 544 } 545 546 /* someone wrote to us, we should reload the timer */ 547 hpwdt_ping(); 548 } 549 550 return len; 551 } 552 553 static struct watchdog_info ident = { 554 .options = WDIOF_SETTIMEOUT | 555 WDIOF_KEEPALIVEPING | 556 WDIOF_MAGICCLOSE, 557 .identity = "HP iLO2 HW Watchdog Timer", 558 }; 559 560 static long hpwdt_ioctl(struct file *file, unsigned int cmd, 561 unsigned long arg) 562 { 563 void __user *argp = (void __user *)arg; 564 int __user *p = argp; 565 int new_margin; 566 int ret = -ENOTTY; 567 568 switch (cmd) { 569 case WDIOC_GETSUPPORT: 570 ret = 0; 571 if (copy_to_user(argp, &ident, sizeof(ident))) 572 ret = -EFAULT; 573 break; 574 575 case WDIOC_GETSTATUS: 576 case WDIOC_GETBOOTSTATUS: 577 ret = put_user(0, p); 578 break; 579 580 case WDIOC_KEEPALIVE: 581 hpwdt_ping(); 582 ret = 0; 583 break; 584 585 case WDIOC_SETTIMEOUT: 586 ret = get_user(new_margin, p); 587 if (ret) 588 break; 589 590 ret = hpwdt_change_timer(new_margin); 591 if (ret) 592 break; 593 594 hpwdt_ping(); 595 /* Fall */ 596 case WDIOC_GETTIMEOUT: 597 ret = put_user(soft_margin, p); 598 break; 599 } 600 return ret; 601 } 602 603 /* 604 * Kernel interfaces 605 */ 606 static const struct file_operations hpwdt_fops = { 607 .owner = THIS_MODULE, 608 .llseek = no_llseek, 609 .write = hpwdt_write, 610 .unlocked_ioctl = hpwdt_ioctl, 611 .open = hpwdt_open, 612 .release = hpwdt_release, 613 }; 614 615 static struct miscdevice hpwdt_miscdev = { 616 .minor = WATCHDOG_MINOR, 617 .name = "watchdog", 618 .fops = &hpwdt_fops, 619 }; 620 621 static struct notifier_block die_notifier = { 622 .notifier_call = hpwdt_pretimeout, 623 .priority = 0x7FFFFFFF, 624 }; 625 626 /* 627 * Init & Exit 628 */ 629 630 static int __devinit hpwdt_init_one(struct pci_dev *dev, 631 const struct pci_device_id *ent) 632 { 633 int retval; 634 635 /* 636 * First let's find out if we are on an iLO2 server. We will 637 * not run on a legacy ASM box. 638 * So we only support the G5 ProLiant servers and higher. 639 */ 640 if (dev->subsystem_vendor != PCI_VENDOR_ID_HP) { 641 dev_warn(&dev->dev, 642 "This server does not have an iLO2 ASIC.\n"); 643 return -ENODEV; 644 } 645 646 if (pci_enable_device(dev)) { 647 dev_warn(&dev->dev, 648 "Not possible to enable PCI Device: 0x%x:0x%x.\n", 649 ent->vendor, ent->device); 650 return -ENODEV; 651 } 652 653 pci_mem_addr = pci_iomap(dev, 1, 0x80); 654 if (!pci_mem_addr) { 655 dev_warn(&dev->dev, 656 "Unable to detect the iLO2 server memory.\n"); 657 retval = -ENOMEM; 658 goto error_pci_iomap; 659 } 660 hpwdt_timer_reg = pci_mem_addr + 0x70; 661 hpwdt_timer_con = pci_mem_addr + 0x72; 662 663 /* Make sure that we have a valid soft_margin */ 664 if (hpwdt_change_timer(soft_margin)) 665 hpwdt_change_timer(DEFAULT_MARGIN); 666 667 /* 668 * We need to map the ROM to get the CRU service. 669 * For 32 bit Operating Systems we need to go through the 32 Bit 670 * BIOS Service Directory 671 * For 64 bit Operating Systems we get that service through SMBIOS. 672 */ 673 retval = detect_cru_service(); 674 if (retval < 0) { 675 dev_warn(&dev->dev, 676 "Unable to detect the %d Bit CRU Service.\n", 677 HPWDT_ARCH); 678 goto error_get_cru; 679 } 680 681 /* 682 * We know this is the only CRU call we need to make so lets keep as 683 * few instructions as possible once the NMI comes in. 684 */ 685 cmn_regs.u1.rah = 0x0D; 686 cmn_regs.u1.ral = 0x02; 687 688 retval = register_die_notifier(&die_notifier); 689 if (retval != 0) { 690 dev_warn(&dev->dev, 691 "Unable to register a die notifier (err=%d).\n", 692 retval); 693 goto error_die_notifier; 694 } 695 696 retval = misc_register(&hpwdt_miscdev); 697 if (retval < 0) { 698 dev_warn(&dev->dev, 699 "Unable to register miscdev on minor=%d (err=%d).\n", 700 WATCHDOG_MINOR, retval); 701 goto error_misc_register; 702 } 703 704 printk(KERN_INFO 705 "hp Watchdog Timer Driver: %s" 706 ", timer margin: %d seconds (nowayout=%d)" 707 ", allow kernel dump: %s (default = 0/OFF).\n", 708 HPWDT_VERSION, soft_margin, nowayout, 709 (allow_kdump == 0) ? "OFF" : "ON"); 710 711 return 0; 712 713 error_misc_register: 714 unregister_die_notifier(&die_notifier); 715 error_die_notifier: 716 if (cru_rom_addr) 717 iounmap(cru_rom_addr); 718 error_get_cru: 719 pci_iounmap(dev, pci_mem_addr); 720 error_pci_iomap: 721 pci_disable_device(dev); 722 return retval; 723 } 724 725 static void __devexit hpwdt_exit(struct pci_dev *dev) 726 { 727 if (!nowayout) 728 hpwdt_stop(); 729 730 misc_deregister(&hpwdt_miscdev); 731 unregister_die_notifier(&die_notifier); 732 733 if (cru_rom_addr) 734 iounmap(cru_rom_addr); 735 pci_iounmap(dev, pci_mem_addr); 736 pci_disable_device(dev); 737 } 738 739 static struct pci_driver hpwdt_driver = { 740 .name = "hpwdt", 741 .id_table = hpwdt_devices, 742 .probe = hpwdt_init_one, 743 .remove = __devexit_p(hpwdt_exit), 744 }; 745 746 static void __exit hpwdt_cleanup(void) 747 { 748 pci_unregister_driver(&hpwdt_driver); 749 } 750 751 static int __init hpwdt_init(void) 752 { 753 return pci_register_driver(&hpwdt_driver); 754 } 755 756 MODULE_AUTHOR("Tom Mingarelli"); 757 MODULE_DESCRIPTION("hp watchdog driver"); 758 MODULE_LICENSE("GPL"); 759 MODULE_VERSION(HPWDT_VERSION); 760 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 761 762 module_param(soft_margin, int, 0); 763 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds"); 764 765 module_param(allow_kdump, int, 0); 766 MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs"); 767 768 module_param(nowayout, int, 0); 769 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 770 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 771 772 module_init(hpwdt_init); 773 module_exit(hpwdt_cleanup); 774