1 #include <linux/module.h> 2 #include <linux/reboot.h> 3 #include <linux/init.h> 4 #include <linux/pm.h> 5 #include <linux/efi.h> 6 #include <linux/dmi.h> 7 #include <linux/sched.h> 8 #include <linux/tboot.h> 9 #include <acpi/reboot.h> 10 #include <asm/io.h> 11 #include <asm/apic.h> 12 #include <asm/desc.h> 13 #include <asm/hpet.h> 14 #include <asm/pgtable.h> 15 #include <asm/proto.h> 16 #include <asm/reboot_fixups.h> 17 #include <asm/reboot.h> 18 #include <asm/pci_x86.h> 19 #include <asm/virtext.h> 20 #include <asm/cpu.h> 21 #include <asm/nmi.h> 22 23 #ifdef CONFIG_X86_32 24 # include <linux/ctype.h> 25 # include <linux/mc146818rtc.h> 26 #else 27 # include <asm/x86_init.h> 28 #endif 29 30 /* 31 * Power off function, if any 32 */ 33 void (*pm_power_off)(void); 34 EXPORT_SYMBOL(pm_power_off); 35 36 static const struct desc_ptr no_idt = {}; 37 static int reboot_mode; 38 enum reboot_type reboot_type = BOOT_KBD; 39 int reboot_force; 40 41 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP) 42 static int reboot_cpu = -1; 43 #endif 44 45 /* This is set if we need to go through the 'emergency' path. 46 * When machine_emergency_restart() is called, we may be on 47 * an inconsistent state and won't be able to do a clean cleanup 48 */ 49 static int reboot_emergency; 50 51 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */ 52 bool port_cf9_safe = false; 53 54 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci] 55 warm Don't set the cold reboot flag 56 cold Set the cold reboot flag 57 bios Reboot by jumping through the BIOS (only for X86_32) 58 smp Reboot by executing reset on BSP or other CPU (only for X86_32) 59 triple Force a triple fault (init) 60 kbd Use the keyboard controller. cold reset (default) 61 acpi Use the RESET_REG in the FADT 62 efi Use efi reset_system runtime service 63 pci Use the so-called "PCI reset register", CF9 64 force Avoid anything that could hang. 65 */ 66 static int __init reboot_setup(char *str) 67 { 68 for (;;) { 69 switch (*str) { 70 case 'w': 71 reboot_mode = 0x1234; 72 break; 73 74 case 'c': 75 reboot_mode = 0; 76 break; 77 78 #ifdef CONFIG_X86_32 79 #ifdef CONFIG_SMP 80 case 's': 81 if (isdigit(*(str+1))) { 82 reboot_cpu = (int) (*(str+1) - '0'); 83 if (isdigit(*(str+2))) 84 reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0'); 85 } 86 /* we will leave sorting out the final value 87 when we are ready to reboot, since we might not 88 have detected BSP APIC ID or smp_num_cpu */ 89 break; 90 #endif /* CONFIG_SMP */ 91 92 case 'b': 93 #endif 94 case 'a': 95 case 'k': 96 case 't': 97 case 'e': 98 case 'p': 99 reboot_type = *str; 100 break; 101 102 case 'f': 103 reboot_force = 1; 104 break; 105 } 106 107 str = strchr(str, ','); 108 if (str) 109 str++; 110 else 111 break; 112 } 113 return 1; 114 } 115 116 __setup("reboot=", reboot_setup); 117 118 119 #ifdef CONFIG_X86_32 120 /* 121 * Reboot options and system auto-detection code provided by 122 * Dell Inc. so their systems "just work". :-) 123 */ 124 125 /* 126 * Some machines require the "reboot=b" commandline option, 127 * this quirk makes that automatic. 128 */ 129 static int __init set_bios_reboot(const struct dmi_system_id *d) 130 { 131 if (reboot_type != BOOT_BIOS) { 132 reboot_type = BOOT_BIOS; 133 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident); 134 } 135 return 0; 136 } 137 138 static struct dmi_system_id __initdata reboot_dmi_table[] = { 139 { /* Handle problems with rebooting on Dell E520's */ 140 .callback = set_bios_reboot, 141 .ident = "Dell E520", 142 .matches = { 143 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 144 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"), 145 }, 146 }, 147 { /* Handle problems with rebooting on Dell 1300's */ 148 .callback = set_bios_reboot, 149 .ident = "Dell PowerEdge 1300", 150 .matches = { 151 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 152 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"), 153 }, 154 }, 155 { /* Handle problems with rebooting on Dell 300's */ 156 .callback = set_bios_reboot, 157 .ident = "Dell PowerEdge 300", 158 .matches = { 159 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 160 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"), 161 }, 162 }, 163 { /* Handle problems with rebooting on Dell Optiplex 745's SFF*/ 164 .callback = set_bios_reboot, 165 .ident = "Dell OptiPlex 745", 166 .matches = { 167 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 168 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 169 }, 170 }, 171 { /* Handle problems with rebooting on Dell Optiplex 745's DFF*/ 172 .callback = set_bios_reboot, 173 .ident = "Dell OptiPlex 745", 174 .matches = { 175 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 176 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 177 DMI_MATCH(DMI_BOARD_NAME, "0MM599"), 178 }, 179 }, 180 { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */ 181 .callback = set_bios_reboot, 182 .ident = "Dell OptiPlex 745", 183 .matches = { 184 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 185 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 186 DMI_MATCH(DMI_BOARD_NAME, "0KW626"), 187 }, 188 }, 189 { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */ 190 .callback = set_bios_reboot, 191 .ident = "Dell OptiPlex 330", 192 .matches = { 193 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 194 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"), 195 DMI_MATCH(DMI_BOARD_NAME, "0KP561"), 196 }, 197 }, 198 { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */ 199 .callback = set_bios_reboot, 200 .ident = "Dell OptiPlex 360", 201 .matches = { 202 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 203 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"), 204 DMI_MATCH(DMI_BOARD_NAME, "0T656F"), 205 }, 206 }, 207 { /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G*/ 208 .callback = set_bios_reboot, 209 .ident = "Dell OptiPlex 760", 210 .matches = { 211 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 212 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"), 213 DMI_MATCH(DMI_BOARD_NAME, "0G919G"), 214 }, 215 }, 216 { /* Handle problems with rebooting on Dell 2400's */ 217 .callback = set_bios_reboot, 218 .ident = "Dell PowerEdge 2400", 219 .matches = { 220 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 221 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"), 222 }, 223 }, 224 { /* Handle problems with rebooting on Dell T5400's */ 225 .callback = set_bios_reboot, 226 .ident = "Dell Precision T5400", 227 .matches = { 228 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 229 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"), 230 }, 231 }, 232 { /* Handle problems with rebooting on Dell T7400's */ 233 .callback = set_bios_reboot, 234 .ident = "Dell Precision T7400", 235 .matches = { 236 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 237 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"), 238 }, 239 }, 240 { /* Handle problems with rebooting on HP laptops */ 241 .callback = set_bios_reboot, 242 .ident = "HP Compaq Laptop", 243 .matches = { 244 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), 245 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"), 246 }, 247 }, 248 { /* Handle problems with rebooting on Dell XPS710 */ 249 .callback = set_bios_reboot, 250 .ident = "Dell XPS710", 251 .matches = { 252 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 253 DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"), 254 }, 255 }, 256 { /* Handle problems with rebooting on Dell DXP061 */ 257 .callback = set_bios_reboot, 258 .ident = "Dell DXP061", 259 .matches = { 260 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 261 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"), 262 }, 263 }, 264 { /* Handle problems with rebooting on Sony VGN-Z540N */ 265 .callback = set_bios_reboot, 266 .ident = "Sony VGN-Z540N", 267 .matches = { 268 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"), 269 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"), 270 }, 271 }, 272 { /* Handle problems with rebooting on CompuLab SBC-FITPC2 */ 273 .callback = set_bios_reboot, 274 .ident = "CompuLab SBC-FITPC2", 275 .matches = { 276 DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"), 277 DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"), 278 }, 279 }, 280 { /* Handle problems with rebooting on ASUS P4S800 */ 281 .callback = set_bios_reboot, 282 .ident = "ASUS P4S800", 283 .matches = { 284 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."), 285 DMI_MATCH(DMI_BOARD_NAME, "P4S800"), 286 }, 287 }, 288 { /* Handle problems with rebooting on VersaLogic Menlow boards */ 289 .callback = set_bios_reboot, 290 .ident = "VersaLogic Menlow based board", 291 .matches = { 292 DMI_MATCH(DMI_BOARD_VENDOR, "VersaLogic Corporation"), 293 DMI_MATCH(DMI_BOARD_NAME, "VersaLogic Menlow board"), 294 }, 295 }, 296 { } 297 }; 298 299 static int __init reboot_init(void) 300 { 301 dmi_check_system(reboot_dmi_table); 302 return 0; 303 } 304 core_initcall(reboot_init); 305 306 extern const unsigned char machine_real_restart_asm[]; 307 extern const u64 machine_real_restart_gdt[3]; 308 309 void machine_real_restart(unsigned int type) 310 { 311 void *restart_va; 312 unsigned long restart_pa; 313 void (*restart_lowmem)(unsigned int); 314 u64 *lowmem_gdt; 315 316 local_irq_disable(); 317 318 /* Write zero to CMOS register number 0x0f, which the BIOS POST 319 routine will recognize as telling it to do a proper reboot. (Well 320 that's what this book in front of me says -- it may only apply to 321 the Phoenix BIOS though, it's not clear). At the same time, 322 disable NMIs by setting the top bit in the CMOS address register, 323 as we're about to do peculiar things to the CPU. I'm not sure if 324 `outb_p' is needed instead of just `outb'. Use it to be on the 325 safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.) 326 */ 327 spin_lock(&rtc_lock); 328 CMOS_WRITE(0x00, 0x8f); 329 spin_unlock(&rtc_lock); 330 331 /* 332 * Switch back to the initial page table. 333 */ 334 load_cr3(initial_page_table); 335 336 /* Write 0x1234 to absolute memory location 0x472. The BIOS reads 337 this on booting to tell it to "Bypass memory test (also warm 338 boot)". This seems like a fairly standard thing that gets set by 339 REBOOT.COM programs, and the previous reset routine did this 340 too. */ 341 *((unsigned short *)0x472) = reboot_mode; 342 343 /* Patch the GDT in the low memory trampoline */ 344 lowmem_gdt = TRAMPOLINE_SYM(machine_real_restart_gdt); 345 346 restart_va = TRAMPOLINE_SYM(machine_real_restart_asm); 347 restart_pa = virt_to_phys(restart_va); 348 restart_lowmem = (void (*)(unsigned int))restart_pa; 349 350 /* GDT[0]: GDT self-pointer */ 351 lowmem_gdt[0] = 352 (u64)(sizeof(machine_real_restart_gdt) - 1) + 353 ((u64)virt_to_phys(lowmem_gdt) << 16); 354 /* GDT[1]: 64K real mode code segment */ 355 lowmem_gdt[1] = 356 GDT_ENTRY(0x009b, restart_pa, 0xffff); 357 358 /* Jump to the identity-mapped low memory code */ 359 restart_lowmem(type); 360 } 361 #ifdef CONFIG_APM_MODULE 362 EXPORT_SYMBOL(machine_real_restart); 363 #endif 364 365 #endif /* CONFIG_X86_32 */ 366 367 /* 368 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot 369 */ 370 static int __init set_pci_reboot(const struct dmi_system_id *d) 371 { 372 if (reboot_type != BOOT_CF9) { 373 reboot_type = BOOT_CF9; 374 printk(KERN_INFO "%s series board detected. " 375 "Selecting PCI-method for reboots.\n", d->ident); 376 } 377 return 0; 378 } 379 380 static struct dmi_system_id __initdata pci_reboot_dmi_table[] = { 381 { /* Handle problems with rebooting on Apple MacBook5 */ 382 .callback = set_pci_reboot, 383 .ident = "Apple MacBook5", 384 .matches = { 385 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 386 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"), 387 }, 388 }, 389 { /* Handle problems with rebooting on Apple MacBookPro5 */ 390 .callback = set_pci_reboot, 391 .ident = "Apple MacBookPro5", 392 .matches = { 393 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 394 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"), 395 }, 396 }, 397 { /* Handle problems with rebooting on Apple Macmini3,1 */ 398 .callback = set_pci_reboot, 399 .ident = "Apple Macmini3,1", 400 .matches = { 401 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 402 DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"), 403 }, 404 }, 405 { /* Handle problems with rebooting on the iMac9,1. */ 406 .callback = set_pci_reboot, 407 .ident = "Apple iMac9,1", 408 .matches = { 409 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 410 DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"), 411 }, 412 }, 413 { } 414 }; 415 416 static int __init pci_reboot_init(void) 417 { 418 dmi_check_system(pci_reboot_dmi_table); 419 return 0; 420 } 421 core_initcall(pci_reboot_init); 422 423 static inline void kb_wait(void) 424 { 425 int i; 426 427 for (i = 0; i < 0x10000; i++) { 428 if ((inb(0x64) & 0x02) == 0) 429 break; 430 udelay(2); 431 } 432 } 433 434 static void vmxoff_nmi(int cpu, struct die_args *args) 435 { 436 cpu_emergency_vmxoff(); 437 } 438 439 /* Use NMIs as IPIs to tell all CPUs to disable virtualization 440 */ 441 static void emergency_vmx_disable_all(void) 442 { 443 /* Just make sure we won't change CPUs while doing this */ 444 local_irq_disable(); 445 446 /* We need to disable VMX on all CPUs before rebooting, otherwise 447 * we risk hanging up the machine, because the CPU ignore INIT 448 * signals when VMX is enabled. 449 * 450 * We can't take any locks and we may be on an inconsistent 451 * state, so we use NMIs as IPIs to tell the other CPUs to disable 452 * VMX and halt. 453 * 454 * For safety, we will avoid running the nmi_shootdown_cpus() 455 * stuff unnecessarily, but we don't have a way to check 456 * if other CPUs have VMX enabled. So we will call it only if the 457 * CPU we are running on has VMX enabled. 458 * 459 * We will miss cases where VMX is not enabled on all CPUs. This 460 * shouldn't do much harm because KVM always enable VMX on all 461 * CPUs anyway. But we can miss it on the small window where KVM 462 * is still enabling VMX. 463 */ 464 if (cpu_has_vmx() && cpu_vmx_enabled()) { 465 /* Disable VMX on this CPU. 466 */ 467 cpu_vmxoff(); 468 469 /* Halt and disable VMX on the other CPUs */ 470 nmi_shootdown_cpus(vmxoff_nmi); 471 472 } 473 } 474 475 476 void __attribute__((weak)) mach_reboot_fixups(void) 477 { 478 } 479 480 static void native_machine_emergency_restart(void) 481 { 482 int i; 483 484 if (reboot_emergency) 485 emergency_vmx_disable_all(); 486 487 tboot_shutdown(TB_SHUTDOWN_REBOOT); 488 489 /* Tell the BIOS if we want cold or warm reboot */ 490 *((unsigned short *)__va(0x472)) = reboot_mode; 491 492 for (;;) { 493 /* Could also try the reset bit in the Hammer NB */ 494 switch (reboot_type) { 495 case BOOT_KBD: 496 mach_reboot_fixups(); /* for board specific fixups */ 497 498 for (i = 0; i < 10; i++) { 499 kb_wait(); 500 udelay(50); 501 outb(0xfe, 0x64); /* pulse reset low */ 502 udelay(50); 503 } 504 505 case BOOT_TRIPLE: 506 load_idt(&no_idt); 507 __asm__ __volatile__("int3"); 508 509 reboot_type = BOOT_KBD; 510 break; 511 512 #ifdef CONFIG_X86_32 513 case BOOT_BIOS: 514 machine_real_restart(MRR_BIOS); 515 516 reboot_type = BOOT_KBD; 517 break; 518 #endif 519 520 case BOOT_ACPI: 521 acpi_reboot(); 522 reboot_type = BOOT_KBD; 523 break; 524 525 case BOOT_EFI: 526 if (efi_enabled) 527 efi.reset_system(reboot_mode ? 528 EFI_RESET_WARM : 529 EFI_RESET_COLD, 530 EFI_SUCCESS, 0, NULL); 531 reboot_type = BOOT_KBD; 532 break; 533 534 case BOOT_CF9: 535 port_cf9_safe = true; 536 /* fall through */ 537 538 case BOOT_CF9_COND: 539 if (port_cf9_safe) { 540 u8 cf9 = inb(0xcf9) & ~6; 541 outb(cf9|2, 0xcf9); /* Request hard reset */ 542 udelay(50); 543 outb(cf9|6, 0xcf9); /* Actually do the reset */ 544 udelay(50); 545 } 546 reboot_type = BOOT_KBD; 547 break; 548 } 549 } 550 } 551 552 void native_machine_shutdown(void) 553 { 554 /* Stop the cpus and apics */ 555 #ifdef CONFIG_SMP 556 557 /* The boot cpu is always logical cpu 0 */ 558 int reboot_cpu_id = 0; 559 560 #ifdef CONFIG_X86_32 561 /* See if there has been given a command line override */ 562 if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && 563 cpu_online(reboot_cpu)) 564 reboot_cpu_id = reboot_cpu; 565 #endif 566 567 /* Make certain the cpu I'm about to reboot on is online */ 568 if (!cpu_online(reboot_cpu_id)) 569 reboot_cpu_id = smp_processor_id(); 570 571 /* Make certain I only run on the appropriate processor */ 572 set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); 573 574 /* O.K Now that I'm on the appropriate processor, 575 * stop all of the others. 576 */ 577 stop_other_cpus(); 578 #endif 579 580 lapic_shutdown(); 581 582 #ifdef CONFIG_X86_IO_APIC 583 disable_IO_APIC(); 584 #endif 585 586 #ifdef CONFIG_HPET_TIMER 587 hpet_disable(); 588 #endif 589 590 #ifdef CONFIG_X86_64 591 x86_platform.iommu_shutdown(); 592 #endif 593 } 594 595 static void __machine_emergency_restart(int emergency) 596 { 597 reboot_emergency = emergency; 598 machine_ops.emergency_restart(); 599 } 600 601 static void native_machine_restart(char *__unused) 602 { 603 printk("machine restart\n"); 604 605 if (!reboot_force) 606 machine_shutdown(); 607 __machine_emergency_restart(0); 608 } 609 610 static void native_machine_halt(void) 611 { 612 /* stop other cpus and apics */ 613 machine_shutdown(); 614 615 tboot_shutdown(TB_SHUTDOWN_HALT); 616 617 /* stop this cpu */ 618 stop_this_cpu(NULL); 619 } 620 621 static void native_machine_power_off(void) 622 { 623 if (pm_power_off) { 624 if (!reboot_force) 625 machine_shutdown(); 626 pm_power_off(); 627 } 628 /* a fallback in case there is no PM info available */ 629 tboot_shutdown(TB_SHUTDOWN_HALT); 630 } 631 632 struct machine_ops machine_ops = { 633 .power_off = native_machine_power_off, 634 .shutdown = native_machine_shutdown, 635 .emergency_restart = native_machine_emergency_restart, 636 .restart = native_machine_restart, 637 .halt = native_machine_halt, 638 #ifdef CONFIG_KEXEC 639 .crash_shutdown = native_machine_crash_shutdown, 640 #endif 641 }; 642 643 void machine_power_off(void) 644 { 645 machine_ops.power_off(); 646 } 647 648 void machine_shutdown(void) 649 { 650 machine_ops.shutdown(); 651 } 652 653 void machine_emergency_restart(void) 654 { 655 __machine_emergency_restart(1); 656 } 657 658 void machine_restart(char *cmd) 659 { 660 machine_ops.restart(cmd); 661 } 662 663 void machine_halt(void) 664 { 665 machine_ops.halt(); 666 } 667 668 #ifdef CONFIG_KEXEC 669 void machine_crash_shutdown(struct pt_regs *regs) 670 { 671 machine_ops.crash_shutdown(regs); 672 } 673 #endif 674 675 676 #if defined(CONFIG_SMP) 677 678 /* This keeps a track of which one is crashing cpu. */ 679 static int crashing_cpu; 680 static nmi_shootdown_cb shootdown_callback; 681 682 static atomic_t waiting_for_crash_ipi; 683 684 static int crash_nmi_callback(struct notifier_block *self, 685 unsigned long val, void *data) 686 { 687 int cpu; 688 689 if (val != DIE_NMI) 690 return NOTIFY_OK; 691 692 cpu = raw_smp_processor_id(); 693 694 /* Don't do anything if this handler is invoked on crashing cpu. 695 * Otherwise, system will completely hang. Crashing cpu can get 696 * an NMI if system was initially booted with nmi_watchdog parameter. 697 */ 698 if (cpu == crashing_cpu) 699 return NOTIFY_STOP; 700 local_irq_disable(); 701 702 shootdown_callback(cpu, (struct die_args *)data); 703 704 atomic_dec(&waiting_for_crash_ipi); 705 /* Assume hlt works */ 706 halt(); 707 for (;;) 708 cpu_relax(); 709 710 return 1; 711 } 712 713 static void smp_send_nmi_allbutself(void) 714 { 715 apic->send_IPI_allbutself(NMI_VECTOR); 716 } 717 718 static struct notifier_block crash_nmi_nb = { 719 .notifier_call = crash_nmi_callback, 720 /* we want to be the first one called */ 721 .priority = NMI_LOCAL_HIGH_PRIOR+1, 722 }; 723 724 /* Halt all other CPUs, calling the specified function on each of them 725 * 726 * This function can be used to halt all other CPUs on crash 727 * or emergency reboot time. The function passed as parameter 728 * will be called inside a NMI handler on all CPUs. 729 */ 730 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 731 { 732 unsigned long msecs; 733 local_irq_disable(); 734 735 /* Make a note of crashing cpu. Will be used in NMI callback.*/ 736 crashing_cpu = safe_smp_processor_id(); 737 738 shootdown_callback = callback; 739 740 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 741 /* Would it be better to replace the trap vector here? */ 742 if (register_die_notifier(&crash_nmi_nb)) 743 return; /* return what? */ 744 /* Ensure the new callback function is set before sending 745 * out the NMI 746 */ 747 wmb(); 748 749 smp_send_nmi_allbutself(); 750 751 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 752 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 753 mdelay(1); 754 msecs--; 755 } 756 757 /* Leave the nmi callback set */ 758 } 759 #else /* !CONFIG_SMP */ 760 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 761 { 762 /* No other CPUs to shoot down */ 763 } 764 #endif 765