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 <linux/delay.h> 10 #include <acpi/reboot.h> 11 #include <asm/io.h> 12 #include <asm/apic.h> 13 #include <asm/desc.h> 14 #include <asm/hpet.h> 15 #include <asm/pgtable.h> 16 #include <asm/proto.h> 17 #include <asm/reboot_fixups.h> 18 #include <asm/reboot.h> 19 #include <asm/pci_x86.h> 20 #include <asm/virtext.h> 21 #include <asm/cpu.h> 22 #include <asm/nmi.h> 23 24 #ifdef CONFIG_X86_32 25 # include <linux/ctype.h> 26 # include <linux/mc146818rtc.h> 27 #else 28 # include <asm/x86_init.h> 29 #endif 30 31 /* 32 * Power off function, if any 33 */ 34 void (*pm_power_off)(void); 35 EXPORT_SYMBOL(pm_power_off); 36 37 static const struct desc_ptr no_idt = {}; 38 static int reboot_mode; 39 enum reboot_type reboot_type = BOOT_KBD; 40 int reboot_force; 41 42 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP) 43 static int reboot_cpu = -1; 44 #endif 45 46 /* This is set if we need to go through the 'emergency' path. 47 * When machine_emergency_restart() is called, we may be on 48 * an inconsistent state and won't be able to do a clean cleanup 49 */ 50 static int reboot_emergency; 51 52 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */ 53 bool port_cf9_safe = false; 54 55 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci] 56 warm Don't set the cold reboot flag 57 cold Set the cold reboot flag 58 bios Reboot by jumping through the BIOS (only for X86_32) 59 smp Reboot by executing reset on BSP or other CPU (only for X86_32) 60 triple Force a triple fault (init) 61 kbd Use the keyboard controller. cold reset (default) 62 acpi Use the RESET_REG in the FADT 63 efi Use efi reset_system runtime service 64 pci Use the so-called "PCI reset register", CF9 65 force Avoid anything that could hang. 66 */ 67 static int __init reboot_setup(char *str) 68 { 69 for (;;) { 70 switch (*str) { 71 case 'w': 72 reboot_mode = 0x1234; 73 break; 74 75 case 'c': 76 reboot_mode = 0; 77 break; 78 79 #ifdef CONFIG_X86_32 80 #ifdef CONFIG_SMP 81 case 's': 82 if (isdigit(*(str+1))) { 83 reboot_cpu = (int) (*(str+1) - '0'); 84 if (isdigit(*(str+2))) 85 reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0'); 86 } 87 /* we will leave sorting out the final value 88 when we are ready to reboot, since we might not 89 have detected BSP APIC ID or smp_num_cpu */ 90 break; 91 #endif /* CONFIG_SMP */ 92 93 case 'b': 94 #endif 95 case 'a': 96 case 'k': 97 case 't': 98 case 'e': 99 case 'p': 100 reboot_type = *str; 101 break; 102 103 case 'f': 104 reboot_force = 1; 105 break; 106 } 107 108 str = strchr(str, ','); 109 if (str) 110 str++; 111 else 112 break; 113 } 114 return 1; 115 } 116 117 __setup("reboot=", reboot_setup); 118 119 120 #ifdef CONFIG_X86_32 121 /* 122 * Reboot options and system auto-detection code provided by 123 * Dell Inc. so their systems "just work". :-) 124 */ 125 126 /* 127 * Some machines require the "reboot=b" commandline option, 128 * this quirk makes that automatic. 129 */ 130 static int __init set_bios_reboot(const struct dmi_system_id *d) 131 { 132 if (reboot_type != BOOT_BIOS) { 133 reboot_type = BOOT_BIOS; 134 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident); 135 } 136 return 0; 137 } 138 139 static struct dmi_system_id __initdata reboot_dmi_table[] = { 140 { /* Handle problems with rebooting on Dell E520's */ 141 .callback = set_bios_reboot, 142 .ident = "Dell E520", 143 .matches = { 144 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 145 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"), 146 }, 147 }, 148 { /* Handle problems with rebooting on Dell 1300's */ 149 .callback = set_bios_reboot, 150 .ident = "Dell PowerEdge 1300", 151 .matches = { 152 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 153 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"), 154 }, 155 }, 156 { /* Handle problems with rebooting on Dell 300's */ 157 .callback = set_bios_reboot, 158 .ident = "Dell PowerEdge 300", 159 .matches = { 160 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 161 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"), 162 }, 163 }, 164 { /* Handle problems with rebooting on Dell Optiplex 745's SFF*/ 165 .callback = set_bios_reboot, 166 .ident = "Dell OptiPlex 745", 167 .matches = { 168 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 169 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 170 }, 171 }, 172 { /* Handle problems with rebooting on Dell Optiplex 745's DFF*/ 173 .callback = set_bios_reboot, 174 .ident = "Dell OptiPlex 745", 175 .matches = { 176 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 177 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 178 DMI_MATCH(DMI_BOARD_NAME, "0MM599"), 179 }, 180 }, 181 { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */ 182 .callback = set_bios_reboot, 183 .ident = "Dell OptiPlex 745", 184 .matches = { 185 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 186 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 187 DMI_MATCH(DMI_BOARD_NAME, "0KW626"), 188 }, 189 }, 190 { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */ 191 .callback = set_bios_reboot, 192 .ident = "Dell OptiPlex 330", 193 .matches = { 194 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 195 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"), 196 DMI_MATCH(DMI_BOARD_NAME, "0KP561"), 197 }, 198 }, 199 { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */ 200 .callback = set_bios_reboot, 201 .ident = "Dell OptiPlex 360", 202 .matches = { 203 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 204 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"), 205 DMI_MATCH(DMI_BOARD_NAME, "0T656F"), 206 }, 207 }, 208 { /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G*/ 209 .callback = set_bios_reboot, 210 .ident = "Dell OptiPlex 760", 211 .matches = { 212 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 213 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"), 214 DMI_MATCH(DMI_BOARD_NAME, "0G919G"), 215 }, 216 }, 217 { /* Handle problems with rebooting on Dell 2400's */ 218 .callback = set_bios_reboot, 219 .ident = "Dell PowerEdge 2400", 220 .matches = { 221 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 222 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"), 223 }, 224 }, 225 { /* Handle problems with rebooting on Dell T5400's */ 226 .callback = set_bios_reboot, 227 .ident = "Dell Precision T5400", 228 .matches = { 229 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 230 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"), 231 }, 232 }, 233 { /* Handle problems with rebooting on Dell T7400's */ 234 .callback = set_bios_reboot, 235 .ident = "Dell Precision T7400", 236 .matches = { 237 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 238 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"), 239 }, 240 }, 241 { /* Handle problems with rebooting on HP laptops */ 242 .callback = set_bios_reboot, 243 .ident = "HP Compaq Laptop", 244 .matches = { 245 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), 246 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"), 247 }, 248 }, 249 { /* Handle problems with rebooting on Dell XPS710 */ 250 .callback = set_bios_reboot, 251 .ident = "Dell XPS710", 252 .matches = { 253 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 254 DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"), 255 }, 256 }, 257 { /* Handle problems with rebooting on Dell DXP061 */ 258 .callback = set_bios_reboot, 259 .ident = "Dell DXP061", 260 .matches = { 261 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 262 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"), 263 }, 264 }, 265 { /* Handle problems with rebooting on Sony VGN-Z540N */ 266 .callback = set_bios_reboot, 267 .ident = "Sony VGN-Z540N", 268 .matches = { 269 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"), 270 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"), 271 }, 272 }, 273 { /* Handle problems with rebooting on CompuLab SBC-FITPC2 */ 274 .callback = set_bios_reboot, 275 .ident = "CompuLab SBC-FITPC2", 276 .matches = { 277 DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"), 278 DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"), 279 }, 280 }, 281 { /* Handle problems with rebooting on ASUS P4S800 */ 282 .callback = set_bios_reboot, 283 .ident = "ASUS P4S800", 284 .matches = { 285 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."), 286 DMI_MATCH(DMI_BOARD_NAME, "P4S800"), 287 }, 288 }, 289 { /* Handle problems with rebooting on VersaLogic Menlow boards */ 290 .callback = set_bios_reboot, 291 .ident = "VersaLogic Menlow based board", 292 .matches = { 293 DMI_MATCH(DMI_BOARD_VENDOR, "VersaLogic Corporation"), 294 DMI_MATCH(DMI_BOARD_NAME, "VersaLogic Menlow board"), 295 }, 296 }, 297 { } 298 }; 299 300 static int __init reboot_init(void) 301 { 302 dmi_check_system(reboot_dmi_table); 303 return 0; 304 } 305 core_initcall(reboot_init); 306 307 extern const unsigned char machine_real_restart_asm[]; 308 extern const u64 machine_real_restart_gdt[3]; 309 310 void machine_real_restart(unsigned int type) 311 { 312 void *restart_va; 313 unsigned long restart_pa; 314 void (*restart_lowmem)(unsigned int); 315 u64 *lowmem_gdt; 316 317 local_irq_disable(); 318 319 /* Write zero to CMOS register number 0x0f, which the BIOS POST 320 routine will recognize as telling it to do a proper reboot. (Well 321 that's what this book in front of me says -- it may only apply to 322 the Phoenix BIOS though, it's not clear). At the same time, 323 disable NMIs by setting the top bit in the CMOS address register, 324 as we're about to do peculiar things to the CPU. I'm not sure if 325 `outb_p' is needed instead of just `outb'. Use it to be on the 326 safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.) 327 */ 328 spin_lock(&rtc_lock); 329 CMOS_WRITE(0x00, 0x8f); 330 spin_unlock(&rtc_lock); 331 332 /* 333 * Switch back to the initial page table. 334 */ 335 load_cr3(initial_page_table); 336 337 /* Write 0x1234 to absolute memory location 0x472. The BIOS reads 338 this on booting to tell it to "Bypass memory test (also warm 339 boot)". This seems like a fairly standard thing that gets set by 340 REBOOT.COM programs, and the previous reset routine did this 341 too. */ 342 *((unsigned short *)0x472) = reboot_mode; 343 344 /* Patch the GDT in the low memory trampoline */ 345 lowmem_gdt = TRAMPOLINE_SYM(machine_real_restart_gdt); 346 347 restart_va = TRAMPOLINE_SYM(machine_real_restart_asm); 348 restart_pa = virt_to_phys(restart_va); 349 restart_lowmem = (void (*)(unsigned int))restart_pa; 350 351 /* GDT[0]: GDT self-pointer */ 352 lowmem_gdt[0] = 353 (u64)(sizeof(machine_real_restart_gdt) - 1) + 354 ((u64)virt_to_phys(lowmem_gdt) << 16); 355 /* GDT[1]: 64K real mode code segment */ 356 lowmem_gdt[1] = 357 GDT_ENTRY(0x009b, restart_pa, 0xffff); 358 359 /* Jump to the identity-mapped low memory code */ 360 restart_lowmem(type); 361 } 362 #ifdef CONFIG_APM_MODULE 363 EXPORT_SYMBOL(machine_real_restart); 364 #endif 365 366 #endif /* CONFIG_X86_32 */ 367 368 /* 369 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot 370 */ 371 static int __init set_pci_reboot(const struct dmi_system_id *d) 372 { 373 if (reboot_type != BOOT_CF9) { 374 reboot_type = BOOT_CF9; 375 printk(KERN_INFO "%s series board detected. " 376 "Selecting PCI-method for reboots.\n", d->ident); 377 } 378 return 0; 379 } 380 381 static struct dmi_system_id __initdata pci_reboot_dmi_table[] = { 382 { /* Handle problems with rebooting on Apple MacBook5 */ 383 .callback = set_pci_reboot, 384 .ident = "Apple MacBook5", 385 .matches = { 386 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 387 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"), 388 }, 389 }, 390 { /* Handle problems with rebooting on Apple MacBookPro5 */ 391 .callback = set_pci_reboot, 392 .ident = "Apple MacBookPro5", 393 .matches = { 394 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 395 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"), 396 }, 397 }, 398 { /* Handle problems with rebooting on Apple Macmini3,1 */ 399 .callback = set_pci_reboot, 400 .ident = "Apple Macmini3,1", 401 .matches = { 402 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 403 DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"), 404 }, 405 }, 406 { /* Handle problems with rebooting on the iMac9,1. */ 407 .callback = set_pci_reboot, 408 .ident = "Apple iMac9,1", 409 .matches = { 410 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 411 DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"), 412 }, 413 }, 414 { } 415 }; 416 417 static int __init pci_reboot_init(void) 418 { 419 dmi_check_system(pci_reboot_dmi_table); 420 return 0; 421 } 422 core_initcall(pci_reboot_init); 423 424 static inline void kb_wait(void) 425 { 426 int i; 427 428 for (i = 0; i < 0x10000; i++) { 429 if ((inb(0x64) & 0x02) == 0) 430 break; 431 udelay(2); 432 } 433 } 434 435 static void vmxoff_nmi(int cpu, struct die_args *args) 436 { 437 cpu_emergency_vmxoff(); 438 } 439 440 /* Use NMIs as IPIs to tell all CPUs to disable virtualization 441 */ 442 static void emergency_vmx_disable_all(void) 443 { 444 /* Just make sure we won't change CPUs while doing this */ 445 local_irq_disable(); 446 447 /* We need to disable VMX on all CPUs before rebooting, otherwise 448 * we risk hanging up the machine, because the CPU ignore INIT 449 * signals when VMX is enabled. 450 * 451 * We can't take any locks and we may be on an inconsistent 452 * state, so we use NMIs as IPIs to tell the other CPUs to disable 453 * VMX and halt. 454 * 455 * For safety, we will avoid running the nmi_shootdown_cpus() 456 * stuff unnecessarily, but we don't have a way to check 457 * if other CPUs have VMX enabled. So we will call it only if the 458 * CPU we are running on has VMX enabled. 459 * 460 * We will miss cases where VMX is not enabled on all CPUs. This 461 * shouldn't do much harm because KVM always enable VMX on all 462 * CPUs anyway. But we can miss it on the small window where KVM 463 * is still enabling VMX. 464 */ 465 if (cpu_has_vmx() && cpu_vmx_enabled()) { 466 /* Disable VMX on this CPU. 467 */ 468 cpu_vmxoff(); 469 470 /* Halt and disable VMX on the other CPUs */ 471 nmi_shootdown_cpus(vmxoff_nmi); 472 473 } 474 } 475 476 477 void __attribute__((weak)) mach_reboot_fixups(void) 478 { 479 } 480 481 static void native_machine_emergency_restart(void) 482 { 483 int i; 484 485 if (reboot_emergency) 486 emergency_vmx_disable_all(); 487 488 tboot_shutdown(TB_SHUTDOWN_REBOOT); 489 490 /* Tell the BIOS if we want cold or warm reboot */ 491 *((unsigned short *)__va(0x472)) = reboot_mode; 492 493 for (;;) { 494 /* Could also try the reset bit in the Hammer NB */ 495 switch (reboot_type) { 496 case BOOT_KBD: 497 mach_reboot_fixups(); /* for board specific fixups */ 498 499 for (i = 0; i < 10; i++) { 500 kb_wait(); 501 udelay(50); 502 outb(0xfe, 0x64); /* pulse reset low */ 503 udelay(50); 504 } 505 506 case BOOT_TRIPLE: 507 load_idt(&no_idt); 508 __asm__ __volatile__("int3"); 509 510 reboot_type = BOOT_KBD; 511 break; 512 513 #ifdef CONFIG_X86_32 514 case BOOT_BIOS: 515 machine_real_restart(MRR_BIOS); 516 517 reboot_type = BOOT_KBD; 518 break; 519 #endif 520 521 case BOOT_ACPI: 522 acpi_reboot(); 523 reboot_type = BOOT_KBD; 524 break; 525 526 case BOOT_EFI: 527 if (efi_enabled) 528 efi.reset_system(reboot_mode ? 529 EFI_RESET_WARM : 530 EFI_RESET_COLD, 531 EFI_SUCCESS, 0, NULL); 532 reboot_type = BOOT_KBD; 533 break; 534 535 case BOOT_CF9: 536 port_cf9_safe = true; 537 /* fall through */ 538 539 case BOOT_CF9_COND: 540 if (port_cf9_safe) { 541 u8 cf9 = inb(0xcf9) & ~6; 542 outb(cf9|2, 0xcf9); /* Request hard reset */ 543 udelay(50); 544 outb(cf9|6, 0xcf9); /* Actually do the reset */ 545 udelay(50); 546 } 547 reboot_type = BOOT_KBD; 548 break; 549 } 550 } 551 } 552 553 void native_machine_shutdown(void) 554 { 555 /* Stop the cpus and apics */ 556 #ifdef CONFIG_SMP 557 558 /* The boot cpu is always logical cpu 0 */ 559 int reboot_cpu_id = 0; 560 561 #ifdef CONFIG_X86_32 562 /* See if there has been given a command line override */ 563 if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && 564 cpu_online(reboot_cpu)) 565 reboot_cpu_id = reboot_cpu; 566 #endif 567 568 /* Make certain the cpu I'm about to reboot on is online */ 569 if (!cpu_online(reboot_cpu_id)) 570 reboot_cpu_id = smp_processor_id(); 571 572 /* Make certain I only run on the appropriate processor */ 573 set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); 574 575 /* O.K Now that I'm on the appropriate processor, 576 * stop all of the others. 577 */ 578 stop_other_cpus(); 579 #endif 580 581 lapic_shutdown(); 582 583 #ifdef CONFIG_X86_IO_APIC 584 disable_IO_APIC(); 585 #endif 586 587 #ifdef CONFIG_HPET_TIMER 588 hpet_disable(); 589 #endif 590 591 #ifdef CONFIG_X86_64 592 x86_platform.iommu_shutdown(); 593 #endif 594 } 595 596 static void __machine_emergency_restart(int emergency) 597 { 598 reboot_emergency = emergency; 599 machine_ops.emergency_restart(); 600 } 601 602 static void native_machine_restart(char *__unused) 603 { 604 printk("machine restart\n"); 605 606 if (!reboot_force) 607 machine_shutdown(); 608 __machine_emergency_restart(0); 609 } 610 611 static void native_machine_halt(void) 612 { 613 /* stop other cpus and apics */ 614 machine_shutdown(); 615 616 tboot_shutdown(TB_SHUTDOWN_HALT); 617 618 /* stop this cpu */ 619 stop_this_cpu(NULL); 620 } 621 622 static void native_machine_power_off(void) 623 { 624 if (pm_power_off) { 625 if (!reboot_force) 626 machine_shutdown(); 627 pm_power_off(); 628 } 629 /* a fallback in case there is no PM info available */ 630 tboot_shutdown(TB_SHUTDOWN_HALT); 631 } 632 633 struct machine_ops machine_ops = { 634 .power_off = native_machine_power_off, 635 .shutdown = native_machine_shutdown, 636 .emergency_restart = native_machine_emergency_restart, 637 .restart = native_machine_restart, 638 .halt = native_machine_halt, 639 #ifdef CONFIG_KEXEC 640 .crash_shutdown = native_machine_crash_shutdown, 641 #endif 642 }; 643 644 void machine_power_off(void) 645 { 646 machine_ops.power_off(); 647 } 648 649 void machine_shutdown(void) 650 { 651 machine_ops.shutdown(); 652 } 653 654 void machine_emergency_restart(void) 655 { 656 __machine_emergency_restart(1); 657 } 658 659 void machine_restart(char *cmd) 660 { 661 machine_ops.restart(cmd); 662 } 663 664 void machine_halt(void) 665 { 666 machine_ops.halt(); 667 } 668 669 #ifdef CONFIG_KEXEC 670 void machine_crash_shutdown(struct pt_regs *regs) 671 { 672 machine_ops.crash_shutdown(regs); 673 } 674 #endif 675 676 677 #if defined(CONFIG_SMP) 678 679 /* This keeps a track of which one is crashing cpu. */ 680 static int crashing_cpu; 681 static nmi_shootdown_cb shootdown_callback; 682 683 static atomic_t waiting_for_crash_ipi; 684 685 static int crash_nmi_callback(struct notifier_block *self, 686 unsigned long val, void *data) 687 { 688 int cpu; 689 690 if (val != DIE_NMI) 691 return NOTIFY_OK; 692 693 cpu = raw_smp_processor_id(); 694 695 /* Don't do anything if this handler is invoked on crashing cpu. 696 * Otherwise, system will completely hang. Crashing cpu can get 697 * an NMI if system was initially booted with nmi_watchdog parameter. 698 */ 699 if (cpu == crashing_cpu) 700 return NOTIFY_STOP; 701 local_irq_disable(); 702 703 shootdown_callback(cpu, (struct die_args *)data); 704 705 atomic_dec(&waiting_for_crash_ipi); 706 /* Assume hlt works */ 707 halt(); 708 for (;;) 709 cpu_relax(); 710 711 return 1; 712 } 713 714 static void smp_send_nmi_allbutself(void) 715 { 716 apic->send_IPI_allbutself(NMI_VECTOR); 717 } 718 719 static struct notifier_block crash_nmi_nb = { 720 .notifier_call = crash_nmi_callback, 721 /* we want to be the first one called */ 722 .priority = NMI_LOCAL_HIGH_PRIOR+1, 723 }; 724 725 /* Halt all other CPUs, calling the specified function on each of them 726 * 727 * This function can be used to halt all other CPUs on crash 728 * or emergency reboot time. The function passed as parameter 729 * will be called inside a NMI handler on all CPUs. 730 */ 731 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 732 { 733 unsigned long msecs; 734 local_irq_disable(); 735 736 /* Make a note of crashing cpu. Will be used in NMI callback.*/ 737 crashing_cpu = safe_smp_processor_id(); 738 739 shootdown_callback = callback; 740 741 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 742 /* Would it be better to replace the trap vector here? */ 743 if (register_die_notifier(&crash_nmi_nb)) 744 return; /* return what? */ 745 /* Ensure the new callback function is set before sending 746 * out the NMI 747 */ 748 wmb(); 749 750 smp_send_nmi_allbutself(); 751 752 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 753 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 754 mdelay(1); 755 msecs--; 756 } 757 758 /* Leave the nmi callback set */ 759 } 760 #else /* !CONFIG_SMP */ 761 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 762 { 763 /* No other CPUs to shoot down */ 764 } 765 #endif 766