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 44 #define PCI_BIOS32_SD_VALUE 0x5F32335F /* "_32_" */ 45 #define CRU_BIOS_SIGNATURE_VALUE 0x55524324 46 #define PCI_BIOS32_PARAGRAPH_LEN 16 47 #define PCI_ROM_BASE1 0x000F0000 48 #define ROM_SIZE 0x10000 49 50 struct bios32_service_dir { 51 u32 signature; 52 u32 entry_point; 53 u8 revision; 54 u8 length; 55 u8 checksum; 56 u8 reserved[5]; 57 }; 58 59 /* type 212 */ 60 struct smbios_cru64_info { 61 u8 type; 62 u8 byte_length; 63 u16 handle; 64 u32 signature; 65 u64 physical_address; 66 u32 double_length; 67 u32 double_offset; 68 }; 69 #define SMBIOS_CRU64_INFORMATION 212 70 71 struct cmn_registers { 72 union { 73 struct { 74 u8 ral; 75 u8 rah; 76 u16 rea2; 77 }; 78 u32 reax; 79 } u1; 80 union { 81 struct { 82 u8 rbl; 83 u8 rbh; 84 u8 reb2l; 85 u8 reb2h; 86 }; 87 u32 rebx; 88 } u2; 89 union { 90 struct { 91 u8 rcl; 92 u8 rch; 93 u16 rec2; 94 }; 95 u32 recx; 96 } u3; 97 union { 98 struct { 99 u8 rdl; 100 u8 rdh; 101 u16 red2; 102 }; 103 u32 redx; 104 } u4; 105 106 u32 resi; 107 u32 redi; 108 u16 rds; 109 u16 res; 110 u32 reflags; 111 } __attribute__((packed)); 112 113 #define DEFAULT_MARGIN 30 114 static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */ 115 static unsigned int reload; /* the computed soft_margin */ 116 static int nowayout = WATCHDOG_NOWAYOUT; 117 static char expect_release; 118 static unsigned long hpwdt_is_open; 119 static unsigned int allow_kdump; 120 121 static void __iomem *pci_mem_addr; /* the PCI-memory address */ 122 static unsigned long __iomem *hpwdt_timer_reg; 123 static unsigned long __iomem *hpwdt_timer_con; 124 125 static DEFINE_SPINLOCK(rom_lock); 126 127 static void *cru_rom_addr; 128 129 static struct cmn_registers cmn_regs; 130 131 static struct pci_device_id hpwdt_devices[] = { 132 { 133 .vendor = PCI_VENDOR_ID_COMPAQ, 134 .device = 0xB203, 135 .subvendor = PCI_ANY_ID, 136 .subdevice = PCI_ANY_ID, 137 }, 138 {0}, /* terminate list */ 139 }; 140 MODULE_DEVICE_TABLE(pci, hpwdt_devices); 141 142 extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs, unsigned long *pRomEntry); 143 144 #ifndef CONFIG_X86_64 145 /* --32 Bit Bios------------------------------------------------------------ */ 146 147 #define HPWDT_ARCH 32 148 149 asm(".text \n\t" 150 ".align 4 \n" 151 "asminline_call: \n\t" 152 "pushl %ebp \n\t" 153 "movl %esp, %ebp \n\t" 154 "pusha \n\t" 155 "pushf \n\t" 156 "push %es \n\t" 157 "push %ds \n\t" 158 "pop %es \n\t" 159 "movl 8(%ebp),%eax \n\t" 160 "movl 4(%eax),%ebx \n\t" 161 "movl 8(%eax),%ecx \n\t" 162 "movl 12(%eax),%edx \n\t" 163 "movl 16(%eax),%esi \n\t" 164 "movl 20(%eax),%edi \n\t" 165 "movl (%eax),%eax \n\t" 166 "push %cs \n\t" 167 "call *12(%ebp) \n\t" 168 "pushf \n\t" 169 "pushl %eax \n\t" 170 "movl 8(%ebp),%eax \n\t" 171 "movl %ebx,4(%eax) \n\t" 172 "movl %ecx,8(%eax) \n\t" 173 "movl %edx,12(%eax) \n\t" 174 "movl %esi,16(%eax) \n\t" 175 "movl %edi,20(%eax) \n\t" 176 "movw %ds,24(%eax) \n\t" 177 "movw %es,26(%eax) \n\t" 178 "popl %ebx \n\t" 179 "movl %ebx,(%eax) \n\t" 180 "popl %ebx \n\t" 181 "movl %ebx,28(%eax) \n\t" 182 "pop %es \n\t" 183 "popf \n\t" 184 "popa \n\t" 185 "leave \n\t" 186 "ret \n\t" 187 ".previous"); 188 189 190 /* 191 * cru_detect 192 * 193 * Routine Description: 194 * This function uses the 32-bit BIOS Service Directory record to 195 * search for a $CRU record. 196 * 197 * Return Value: 198 * 0 : SUCCESS 199 * <0 : FAILURE 200 */ 201 static int __devinit cru_detect(unsigned long map_entry, 202 unsigned long map_offset) 203 { 204 void *bios32_map; 205 unsigned long *bios32_entrypoint; 206 unsigned long cru_physical_address; 207 unsigned long cru_length; 208 unsigned long physical_bios_base = 0; 209 unsigned long physical_bios_offset = 0; 210 int retval = -ENODEV; 211 212 bios32_map = ioremap(map_entry, (2 * PAGE_SIZE)); 213 214 if (bios32_map == NULL) 215 return -ENODEV; 216 217 bios32_entrypoint = bios32_map + map_offset; 218 219 cmn_regs.u1.reax = CRU_BIOS_SIGNATURE_VALUE; 220 221 asminline_call(&cmn_regs, bios32_entrypoint); 222 223 if (cmn_regs.u1.ral != 0) { 224 printk(KERN_WARNING 225 "hpwdt: Call succeeded but with an error: 0x%x\n", 226 cmn_regs.u1.ral); 227 } else { 228 physical_bios_base = cmn_regs.u2.rebx; 229 physical_bios_offset = cmn_regs.u4.redx; 230 cru_length = cmn_regs.u3.recx; 231 cru_physical_address = 232 physical_bios_base + physical_bios_offset; 233 234 /* If the values look OK, then map it in. */ 235 if ((physical_bios_base + physical_bios_offset)) { 236 cru_rom_addr = 237 ioremap(cru_physical_address, cru_length); 238 if (cru_rom_addr) 239 retval = 0; 240 } 241 242 printk(KERN_DEBUG "hpwdt: CRU Base Address: 0x%lx\n", 243 physical_bios_base); 244 printk(KERN_DEBUG "hpwdt: CRU Offset Address: 0x%lx\n", 245 physical_bios_offset); 246 printk(KERN_DEBUG "hpwdt: CRU Length: 0x%lx\n", 247 cru_length); 248 printk(KERN_DEBUG "hpwdt: CRU Mapped Address: 0x%x\n", 249 (unsigned int)&cru_rom_addr); 250 } 251 iounmap(bios32_map); 252 return retval; 253 } 254 255 /* 256 * bios_checksum 257 */ 258 static int __devinit bios_checksum(const char __iomem *ptr, int len) 259 { 260 char sum = 0; 261 int i; 262 263 /* 264 * calculate checksum of size bytes. This should add up 265 * to zero if we have a valid header. 266 */ 267 for (i = 0; i < len; i++) 268 sum += ptr[i]; 269 270 return ((sum == 0) && (len > 0)); 271 } 272 273 /* 274 * bios32_present 275 * 276 * Routine Description: 277 * This function finds the 32-bit BIOS Service Directory 278 * 279 * Return Value: 280 * 0 : SUCCESS 281 * <0 : FAILURE 282 */ 283 static int __devinit bios32_present(const char __iomem *p) 284 { 285 struct bios32_service_dir *bios_32_ptr; 286 int length; 287 unsigned long map_entry, map_offset; 288 289 bios_32_ptr = (struct bios32_service_dir *) p; 290 291 /* 292 * Search for signature by checking equal to the swizzled value 293 * instead of calling another routine to perform a strcmp. 294 */ 295 if (bios_32_ptr->signature == PCI_BIOS32_SD_VALUE) { 296 length = bios_32_ptr->length * PCI_BIOS32_PARAGRAPH_LEN; 297 if (bios_checksum(p, length)) { 298 /* 299 * According to the spec, we're looking for the 300 * first 4KB-aligned address below the entrypoint 301 * listed in the header. The Service Directory code 302 * is guaranteed to occupy no more than 2 4KB pages. 303 */ 304 map_entry = bios_32_ptr->entry_point & ~(PAGE_SIZE - 1); 305 map_offset = bios_32_ptr->entry_point - map_entry; 306 307 return cru_detect(map_entry, map_offset); 308 } 309 } 310 return -ENODEV; 311 } 312 313 static int __devinit detect_cru_service(void) 314 { 315 char __iomem *p, *q; 316 int rc = -1; 317 318 /* 319 * Search from 0x0f0000 through 0x0fffff, inclusive. 320 */ 321 p = ioremap(PCI_ROM_BASE1, ROM_SIZE); 322 if (p == NULL) 323 return -ENOMEM; 324 325 for (q = p; q < p + ROM_SIZE; q += 16) { 326 rc = bios32_present(q); 327 if (!rc) 328 break; 329 } 330 iounmap(p); 331 return rc; 332 } 333 334 #else 335 /* --64 Bit Bios------------------------------------------------------------ */ 336 337 #define HPWDT_ARCH 64 338 339 asm(".text \n\t" 340 ".align 4 \n" 341 "asminline_call: \n\t" 342 "pushq %rbp \n\t" 343 "movq %rsp, %rbp \n\t" 344 "pushq %rax \n\t" 345 "pushq %rbx \n\t" 346 "pushq %rdx \n\t" 347 "pushq %r12 \n\t" 348 "pushq %r9 \n\t" 349 "movq %rsi, %r12 \n\t" 350 "movq %rdi, %r9 \n\t" 351 "movl 4(%r9),%ebx \n\t" 352 "movl 8(%r9),%ecx \n\t" 353 "movl 12(%r9),%edx \n\t" 354 "movl 16(%r9),%esi \n\t" 355 "movl 20(%r9),%edi \n\t" 356 "movl (%r9),%eax \n\t" 357 "call *%r12 \n\t" 358 "pushfq \n\t" 359 "popq %r12 \n\t" 360 "movl %eax, (%r9) \n\t" 361 "movl %ebx, 4(%r9) \n\t" 362 "movl %ecx, 8(%r9) \n\t" 363 "movl %edx, 12(%r9) \n\t" 364 "movl %esi, 16(%r9) \n\t" 365 "movl %edi, 20(%r9) \n\t" 366 "movq %r12, %rax \n\t" 367 "movl %eax, 28(%r9) \n\t" 368 "popq %r9 \n\t" 369 "popq %r12 \n\t" 370 "popq %rdx \n\t" 371 "popq %rbx \n\t" 372 "popq %rax \n\t" 373 "leave \n\t" 374 "ret \n\t" 375 ".previous"); 376 377 /* 378 * dmi_find_cru 379 * 380 * Routine Description: 381 * This function checks whether or not a SMBIOS/DMI record is 382 * the 64bit CRU info or not 383 */ 384 static void __devinit dmi_find_cru(const struct dmi_header *dm) 385 { 386 struct smbios_cru64_info *smbios_cru64_ptr; 387 unsigned long cru_physical_address; 388 389 if (dm->type == SMBIOS_CRU64_INFORMATION) { 390 smbios_cru64_ptr = (struct smbios_cru64_info *) dm; 391 if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) { 392 cru_physical_address = 393 smbios_cru64_ptr->physical_address + 394 smbios_cru64_ptr->double_offset; 395 cru_rom_addr = ioremap(cru_physical_address, 396 smbios_cru64_ptr->double_length); 397 } 398 } 399 } 400 401 static int __devinit detect_cru_service(void) 402 { 403 cru_rom_addr = NULL; 404 405 dmi_walk(dmi_find_cru); 406 407 /* if cru_rom_addr has been set then we found a CRU service */ 408 return ((cru_rom_addr != NULL) ? 0 : -ENODEV); 409 } 410 411 /* ------------------------------------------------------------------------- */ 412 413 #endif 414 415 /* 416 * Watchdog operations 417 */ 418 static void hpwdt_start(void) 419 { 420 reload = (soft_margin * 1000) / 128; 421 iowrite16(reload, hpwdt_timer_reg); 422 iowrite16(0x85, hpwdt_timer_con); 423 } 424 425 static void hpwdt_stop(void) 426 { 427 unsigned long data; 428 429 data = ioread16(hpwdt_timer_con); 430 data &= 0xFE; 431 iowrite16(data, hpwdt_timer_con); 432 } 433 434 static void hpwdt_ping(void) 435 { 436 iowrite16(reload, hpwdt_timer_reg); 437 } 438 439 static int hpwdt_change_timer(int new_margin) 440 { 441 /* Arbitrary, can't find the card's limits */ 442 if (new_margin < 30 || new_margin > 600) { 443 printk(KERN_WARNING 444 "hpwdt: New value passed in is invalid: %d seconds.\n", 445 new_margin); 446 return -EINVAL; 447 } 448 449 soft_margin = new_margin; 450 printk(KERN_DEBUG 451 "hpwdt: New timer passed in is %d seconds.\n", 452 new_margin); 453 reload = (soft_margin * 1000) / 128; 454 455 return 0; 456 } 457 458 /* 459 * NMI Handler 460 */ 461 static int hpwdt_pretimeout(struct notifier_block *nb, unsigned long ulReason, 462 void *data) 463 { 464 unsigned long rom_pl; 465 static int die_nmi_called; 466 467 if (ulReason != DIE_NMI && ulReason != DIE_NMI_IPI) 468 return NOTIFY_OK; 469 470 spin_lock_irqsave(&rom_lock, rom_pl); 471 if (!die_nmi_called) 472 asminline_call(&cmn_regs, cru_rom_addr); 473 die_nmi_called = 1; 474 spin_unlock_irqrestore(&rom_lock, rom_pl); 475 if (cmn_regs.u1.ral == 0) { 476 printk(KERN_WARNING "hpwdt: An NMI occurred, " 477 "but unable to determine source.\n"); 478 } else { 479 if (allow_kdump) 480 hpwdt_stop(); 481 panic("An NMI occurred, please see the Integrated " 482 "Management Log for details.\n"); 483 } 484 485 return NOTIFY_STOP; 486 } 487 488 /* 489 * /dev/watchdog handling 490 */ 491 static int hpwdt_open(struct inode *inode, struct file *file) 492 { 493 /* /dev/watchdog can only be opened once */ 494 if (test_and_set_bit(0, &hpwdt_is_open)) 495 return -EBUSY; 496 497 /* Start the watchdog */ 498 hpwdt_start(); 499 hpwdt_ping(); 500 501 return nonseekable_open(inode, file); 502 } 503 504 static int hpwdt_release(struct inode *inode, struct file *file) 505 { 506 /* Stop the watchdog */ 507 if (expect_release == 42) { 508 hpwdt_stop(); 509 } else { 510 printk(KERN_CRIT 511 "hpwdt: Unexpected close, not stopping watchdog!\n"); 512 hpwdt_ping(); 513 } 514 515 expect_release = 0; 516 517 /* /dev/watchdog is being closed, make sure it can be re-opened */ 518 clear_bit(0, &hpwdt_is_open); 519 520 return 0; 521 } 522 523 static ssize_t hpwdt_write(struct file *file, const char __user *data, 524 size_t len, loff_t *ppos) 525 { 526 /* See if we got the magic character 'V' and reload the timer */ 527 if (len) { 528 if (!nowayout) { 529 size_t i; 530 531 /* note: just in case someone wrote the magic character 532 * five months ago... */ 533 expect_release = 0; 534 535 /* scan to see whether or not we got the magic char. */ 536 for (i = 0; i != len; i++) { 537 char c; 538 if (get_user(c, data + i)) 539 return -EFAULT; 540 if (c == 'V') 541 expect_release = 42; 542 } 543 } 544 545 /* someone wrote to us, we should reload the timer */ 546 hpwdt_ping(); 547 } 548 549 return len; 550 } 551 552 static struct watchdog_info ident = { 553 .options = WDIOF_SETTIMEOUT | 554 WDIOF_KEEPALIVEPING | 555 WDIOF_MAGICCLOSE, 556 .identity = "HP iLO2 HW Watchdog Timer", 557 }; 558 559 static long hpwdt_ioctl(struct file *file, unsigned int cmd, 560 unsigned long arg) 561 { 562 void __user *argp = (void __user *)arg; 563 int __user *p = argp; 564 int new_margin; 565 int ret = -ENOTTY; 566 567 switch (cmd) { 568 case WDIOC_GETSUPPORT: 569 ret = 0; 570 if (copy_to_user(argp, &ident, sizeof(ident))) 571 ret = -EFAULT; 572 break; 573 574 case WDIOC_GETSTATUS: 575 case WDIOC_GETBOOTSTATUS: 576 ret = put_user(0, p); 577 break; 578 579 case WDIOC_KEEPALIVE: 580 hpwdt_ping(); 581 ret = 0; 582 break; 583 584 case WDIOC_SETTIMEOUT: 585 ret = get_user(new_margin, p); 586 if (ret) 587 break; 588 589 ret = hpwdt_change_timer(new_margin); 590 if (ret) 591 break; 592 593 hpwdt_ping(); 594 /* Fall */ 595 case WDIOC_GETTIMEOUT: 596 ret = put_user(soft_margin, p); 597 break; 598 } 599 return ret; 600 } 601 602 /* 603 * Kernel interfaces 604 */ 605 static struct file_operations hpwdt_fops = { 606 .owner = THIS_MODULE, 607 .llseek = no_llseek, 608 .write = hpwdt_write, 609 .unlocked_ioctl = hpwdt_ioctl, 610 .open = hpwdt_open, 611 .release = hpwdt_release, 612 }; 613 614 static struct miscdevice hpwdt_miscdev = { 615 .minor = WATCHDOG_MINOR, 616 .name = "watchdog", 617 .fops = &hpwdt_fops, 618 }; 619 620 static struct notifier_block die_notifier = { 621 .notifier_call = hpwdt_pretimeout, 622 .priority = 0x7FFFFFFF, 623 }; 624 625 /* 626 * Init & Exit 627 */ 628 629 static int __devinit hpwdt_init_one(struct pci_dev *dev, 630 const struct pci_device_id *ent) 631 { 632 int retval; 633 634 /* 635 * First let's find out if we are on an iLO2 server. We will 636 * not run on a legacy ASM box. 637 * So we only support the G5 ProLiant servers and higher. 638 */ 639 if (dev->subsystem_vendor != PCI_VENDOR_ID_HP) { 640 dev_warn(&dev->dev, 641 "This server does not have an iLO2 ASIC.\n"); 642 return -ENODEV; 643 } 644 645 if (pci_enable_device(dev)) { 646 dev_warn(&dev->dev, 647 "Not possible to enable PCI Device: 0x%x:0x%x.\n", 648 ent->vendor, ent->device); 649 return -ENODEV; 650 } 651 652 pci_mem_addr = pci_iomap(dev, 1, 0x80); 653 if (!pci_mem_addr) { 654 dev_warn(&dev->dev, 655 "Unable to detect the iLO2 server memory.\n"); 656 retval = -ENOMEM; 657 goto error_pci_iomap; 658 } 659 hpwdt_timer_reg = pci_mem_addr + 0x70; 660 hpwdt_timer_con = pci_mem_addr + 0x72; 661 662 /* Make sure that we have a valid soft_margin */ 663 if (hpwdt_change_timer(soft_margin)) 664 hpwdt_change_timer(DEFAULT_MARGIN); 665 666 /* 667 * We need to map the ROM to get the CRU service. 668 * For 32 bit Operating Systems we need to go through the 32 Bit 669 * BIOS Service Directory 670 * For 64 bit Operating Systems we get that service through SMBIOS. 671 */ 672 retval = detect_cru_service(); 673 if (retval < 0) { 674 dev_warn(&dev->dev, 675 "Unable to detect the %d Bit CRU Service.\n", 676 HPWDT_ARCH); 677 goto error_get_cru; 678 } 679 680 /* 681 * We know this is the only CRU call we need to make so lets keep as 682 * few instructions as possible once the NMI comes in. 683 */ 684 cmn_regs.u1.rah = 0x0D; 685 cmn_regs.u1.ral = 0x02; 686 687 retval = register_die_notifier(&die_notifier); 688 if (retval != 0) { 689 dev_warn(&dev->dev, 690 "Unable to register a die notifier (err=%d).\n", 691 retval); 692 goto error_die_notifier; 693 } 694 695 retval = misc_register(&hpwdt_miscdev); 696 if (retval < 0) { 697 dev_warn(&dev->dev, 698 "Unable to register miscdev on minor=%d (err=%d).\n", 699 WATCHDOG_MINOR, retval); 700 goto error_misc_register; 701 } 702 703 printk(KERN_INFO 704 "hp Watchdog Timer Driver: 1.00" 705 ", timer margin: %d seconds (nowayout=%d)" 706 ", allow kernel dump: %s (default = 0/OFF).\n", 707 soft_margin, nowayout, (allow_kdump == 0) ? "OFF" : "ON"); 708 709 return 0; 710 711 error_misc_register: 712 unregister_die_notifier(&die_notifier); 713 error_die_notifier: 714 if (cru_rom_addr) 715 iounmap(cru_rom_addr); 716 error_get_cru: 717 pci_iounmap(dev, pci_mem_addr); 718 error_pci_iomap: 719 pci_disable_device(dev); 720 return retval; 721 } 722 723 static void __devexit hpwdt_exit(struct pci_dev *dev) 724 { 725 if (!nowayout) 726 hpwdt_stop(); 727 728 misc_deregister(&hpwdt_miscdev); 729 unregister_die_notifier(&die_notifier); 730 731 if (cru_rom_addr) 732 iounmap(cru_rom_addr); 733 pci_iounmap(dev, pci_mem_addr); 734 pci_disable_device(dev); 735 } 736 737 static struct pci_driver hpwdt_driver = { 738 .name = "hpwdt", 739 .id_table = hpwdt_devices, 740 .probe = hpwdt_init_one, 741 .remove = __devexit_p(hpwdt_exit), 742 }; 743 744 static void __exit hpwdt_cleanup(void) 745 { 746 pci_unregister_driver(&hpwdt_driver); 747 } 748 749 static int __init hpwdt_init(void) 750 { 751 return pci_register_driver(&hpwdt_driver); 752 } 753 754 MODULE_AUTHOR("Tom Mingarelli"); 755 MODULE_DESCRIPTION("hp watchdog driver"); 756 MODULE_LICENSE("GPL"); 757 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 758 759 module_param(soft_margin, int, 0); 760 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds"); 761 762 module_param(allow_kdump, int, 0); 763 MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs"); 764 765 module_param(nowayout, int, 0); 766 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 767 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 768 769 module_init(hpwdt_init); 770 module_exit(hpwdt_cleanup); 771