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 <acpi/reboot.h> 7 #include <asm/io.h> 8 #include <asm/apic.h> 9 #include <asm/desc.h> 10 #include <asm/hpet.h> 11 #include <asm/pgtable.h> 12 #include <asm/proto.h> 13 #include <asm/reboot_fixups.h> 14 #include <asm/reboot.h> 15 #include <asm/pci_x86.h> 16 #include <asm/virtext.h> 17 #include <asm/cpu.h> 18 19 #ifdef CONFIG_X86_32 20 # include <linux/dmi.h> 21 # include <linux/ctype.h> 22 # include <linux/mc146818rtc.h> 23 #else 24 # include <asm/iommu.h> 25 #endif 26 27 /* 28 * Power off function, if any 29 */ 30 void (*pm_power_off)(void); 31 EXPORT_SYMBOL(pm_power_off); 32 33 static const struct desc_ptr no_idt = {}; 34 static int reboot_mode; 35 enum reboot_type reboot_type = BOOT_KBD; 36 int reboot_force; 37 38 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP) 39 static int reboot_cpu = -1; 40 #endif 41 42 /* This is set if we need to go through the 'emergency' path. 43 * When machine_emergency_restart() is called, we may be on 44 * an inconsistent state and won't be able to do a clean cleanup 45 */ 46 static int reboot_emergency; 47 48 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */ 49 bool port_cf9_safe = false; 50 51 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci] 52 warm Don't set the cold reboot flag 53 cold Set the cold reboot flag 54 bios Reboot by jumping through the BIOS (only for X86_32) 55 smp Reboot by executing reset on BSP or other CPU (only for X86_32) 56 triple Force a triple fault (init) 57 kbd Use the keyboard controller. cold reset (default) 58 acpi Use the RESET_REG in the FADT 59 efi Use efi reset_system runtime service 60 pci Use the so-called "PCI reset register", CF9 61 force Avoid anything that could hang. 62 */ 63 static int __init reboot_setup(char *str) 64 { 65 for (;;) { 66 switch (*str) { 67 case 'w': 68 reboot_mode = 0x1234; 69 break; 70 71 case 'c': 72 reboot_mode = 0; 73 break; 74 75 #ifdef CONFIG_X86_32 76 #ifdef CONFIG_SMP 77 case 's': 78 if (isdigit(*(str+1))) { 79 reboot_cpu = (int) (*(str+1) - '0'); 80 if (isdigit(*(str+2))) 81 reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0'); 82 } 83 /* we will leave sorting out the final value 84 when we are ready to reboot, since we might not 85 have set up boot_cpu_id or smp_num_cpu */ 86 break; 87 #endif /* CONFIG_SMP */ 88 89 case 'b': 90 #endif 91 case 'a': 92 case 'k': 93 case 't': 94 case 'e': 95 case 'p': 96 reboot_type = *str; 97 break; 98 99 case 'f': 100 reboot_force = 1; 101 break; 102 } 103 104 str = strchr(str, ','); 105 if (str) 106 str++; 107 else 108 break; 109 } 110 return 1; 111 } 112 113 __setup("reboot=", reboot_setup); 114 115 116 #ifdef CONFIG_X86_32 117 /* 118 * Reboot options and system auto-detection code provided by 119 * Dell Inc. so their systems "just work". :-) 120 */ 121 122 /* 123 * Some machines require the "reboot=b" commandline option, 124 * this quirk makes that automatic. 125 */ 126 static int __init set_bios_reboot(const struct dmi_system_id *d) 127 { 128 if (reboot_type != BOOT_BIOS) { 129 reboot_type = BOOT_BIOS; 130 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident); 131 } 132 return 0; 133 } 134 135 static struct dmi_system_id __initdata reboot_dmi_table[] = { 136 { /* Handle problems with rebooting on Dell E520's */ 137 .callback = set_bios_reboot, 138 .ident = "Dell E520", 139 .matches = { 140 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 141 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"), 142 }, 143 }, 144 { /* Handle problems with rebooting on Dell 1300's */ 145 .callback = set_bios_reboot, 146 .ident = "Dell PowerEdge 1300", 147 .matches = { 148 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 149 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"), 150 }, 151 }, 152 { /* Handle problems with rebooting on Dell 300's */ 153 .callback = set_bios_reboot, 154 .ident = "Dell PowerEdge 300", 155 .matches = { 156 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 157 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"), 158 }, 159 }, 160 { /* Handle problems with rebooting on Dell Optiplex 745's SFF*/ 161 .callback = set_bios_reboot, 162 .ident = "Dell OptiPlex 745", 163 .matches = { 164 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 165 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 166 }, 167 }, 168 { /* Handle problems with rebooting on Dell Optiplex 745's DFF*/ 169 .callback = set_bios_reboot, 170 .ident = "Dell OptiPlex 745", 171 .matches = { 172 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 173 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 174 DMI_MATCH(DMI_BOARD_NAME, "0MM599"), 175 }, 176 }, 177 { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */ 178 .callback = set_bios_reboot, 179 .ident = "Dell OptiPlex 745", 180 .matches = { 181 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 182 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), 183 DMI_MATCH(DMI_BOARD_NAME, "0KW626"), 184 }, 185 }, 186 { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */ 187 .callback = set_bios_reboot, 188 .ident = "Dell OptiPlex 330", 189 .matches = { 190 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 191 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"), 192 DMI_MATCH(DMI_BOARD_NAME, "0KP561"), 193 }, 194 }, 195 { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */ 196 .callback = set_bios_reboot, 197 .ident = "Dell OptiPlex 360", 198 .matches = { 199 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 200 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"), 201 DMI_MATCH(DMI_BOARD_NAME, "0T656F"), 202 }, 203 }, 204 { /* Handle problems with rebooting on Dell 2400's */ 205 .callback = set_bios_reboot, 206 .ident = "Dell PowerEdge 2400", 207 .matches = { 208 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), 209 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"), 210 }, 211 }, 212 { /* Handle problems with rebooting on Dell T5400's */ 213 .callback = set_bios_reboot, 214 .ident = "Dell Precision T5400", 215 .matches = { 216 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 217 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"), 218 }, 219 }, 220 { /* Handle problems with rebooting on HP laptops */ 221 .callback = set_bios_reboot, 222 .ident = "HP Compaq Laptop", 223 .matches = { 224 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), 225 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"), 226 }, 227 }, 228 { /* Handle problems with rebooting on Dell XPS710 */ 229 .callback = set_bios_reboot, 230 .ident = "Dell XPS710", 231 .matches = { 232 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 233 DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"), 234 }, 235 }, 236 { /* Handle problems with rebooting on Dell DXP061 */ 237 .callback = set_bios_reboot, 238 .ident = "Dell DXP061", 239 .matches = { 240 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 241 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"), 242 }, 243 }, 244 { /* Handle problems with rebooting on Sony VGN-Z540N */ 245 .callback = set_bios_reboot, 246 .ident = "Sony VGN-Z540N", 247 .matches = { 248 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"), 249 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"), 250 }, 251 }, 252 { /* Handle problems with rebooting on CompuLab SBC-FITPC2 */ 253 .callback = set_bios_reboot, 254 .ident = "CompuLab SBC-FITPC2", 255 .matches = { 256 DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"), 257 DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"), 258 }, 259 }, 260 { } 261 }; 262 263 static int __init reboot_init(void) 264 { 265 dmi_check_system(reboot_dmi_table); 266 return 0; 267 } 268 core_initcall(reboot_init); 269 270 /* The following code and data reboots the machine by switching to real 271 mode and jumping to the BIOS reset entry point, as if the CPU has 272 really been reset. The previous version asked the keyboard 273 controller to pulse the CPU reset line, which is more thorough, but 274 doesn't work with at least one type of 486 motherboard. It is easy 275 to stop this code working; hence the copious comments. */ 276 static const unsigned long long 277 real_mode_gdt_entries [3] = 278 { 279 0x0000000000000000ULL, /* Null descriptor */ 280 0x00009b000000ffffULL, /* 16-bit real-mode 64k code at 0x00000000 */ 281 0x000093000100ffffULL /* 16-bit real-mode 64k data at 0x00000100 */ 282 }; 283 284 static const struct desc_ptr 285 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries }, 286 real_mode_idt = { 0x3ff, 0 }; 287 288 /* This is 16-bit protected mode code to disable paging and the cache, 289 switch to real mode and jump to the BIOS reset code. 290 291 The instruction that switches to real mode by writing to CR0 must be 292 followed immediately by a far jump instruction, which set CS to a 293 valid value for real mode, and flushes the prefetch queue to avoid 294 running instructions that have already been decoded in protected 295 mode. 296 297 Clears all the flags except ET, especially PG (paging), PE 298 (protected-mode enable) and TS (task switch for coprocessor state 299 save). Flushes the TLB after paging has been disabled. Sets CD and 300 NW, to disable the cache on a 486, and invalidates the cache. This 301 is more like the state of a 486 after reset. I don't know if 302 something else should be done for other chips. 303 304 More could be done here to set up the registers as if a CPU reset had 305 occurred; hopefully real BIOSs don't assume much. */ 306 static const unsigned char real_mode_switch [] = 307 { 308 0x66, 0x0f, 0x20, 0xc0, /* movl %cr0,%eax */ 309 0x66, 0x83, 0xe0, 0x11, /* andl $0x00000011,%eax */ 310 0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */ 311 0x66, 0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */ 312 0x66, 0x0f, 0x22, 0xd8, /* movl %eax,%cr3 */ 313 0x66, 0x0f, 0x20, 0xc3, /* movl %cr0,%ebx */ 314 0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60, /* andl $0x60000000,%ebx */ 315 0x74, 0x02, /* jz f */ 316 0x0f, 0x09, /* wbinvd */ 317 0x24, 0x10, /* f: andb $0x10,al */ 318 0x66, 0x0f, 0x22, 0xc0 /* movl %eax,%cr0 */ 319 }; 320 static const unsigned char jump_to_bios [] = 321 { 322 0xea, 0x00, 0x00, 0xff, 0xff /* ljmp $0xffff,$0x0000 */ 323 }; 324 325 /* 326 * Switch to real mode and then execute the code 327 * specified by the code and length parameters. 328 * We assume that length will aways be less that 100! 329 */ 330 void machine_real_restart(const unsigned char *code, int length) 331 { 332 local_irq_disable(); 333 334 /* Write zero to CMOS register number 0x0f, which the BIOS POST 335 routine will recognize as telling it to do a proper reboot. (Well 336 that's what this book in front of me says -- it may only apply to 337 the Phoenix BIOS though, it's not clear). At the same time, 338 disable NMIs by setting the top bit in the CMOS address register, 339 as we're about to do peculiar things to the CPU. I'm not sure if 340 `outb_p' is needed instead of just `outb'. Use it to be on the 341 safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.) 342 */ 343 spin_lock(&rtc_lock); 344 CMOS_WRITE(0x00, 0x8f); 345 spin_unlock(&rtc_lock); 346 347 /* Remap the kernel at virtual address zero, as well as offset zero 348 from the kernel segment. This assumes the kernel segment starts at 349 virtual address PAGE_OFFSET. */ 350 memcpy(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY, 351 sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS); 352 353 /* 354 * Use `swapper_pg_dir' as our page directory. 355 */ 356 load_cr3(swapper_pg_dir); 357 358 /* Write 0x1234 to absolute memory location 0x472. The BIOS reads 359 this on booting to tell it to "Bypass memory test (also warm 360 boot)". This seems like a fairly standard thing that gets set by 361 REBOOT.COM programs, and the previous reset routine did this 362 too. */ 363 *((unsigned short *)0x472) = reboot_mode; 364 365 /* For the switch to real mode, copy some code to low memory. It has 366 to be in the first 64k because it is running in 16-bit mode, and it 367 has to have the same physical and virtual address, because it turns 368 off paging. Copy it near the end of the first page, out of the way 369 of BIOS variables. */ 370 memcpy((void *)(0x1000 - sizeof(real_mode_switch) - 100), 371 real_mode_switch, sizeof (real_mode_switch)); 372 memcpy((void *)(0x1000 - 100), code, length); 373 374 /* Set up the IDT for real mode. */ 375 load_idt(&real_mode_idt); 376 377 /* Set up a GDT from which we can load segment descriptors for real 378 mode. The GDT is not used in real mode; it is just needed here to 379 prepare the descriptors. */ 380 load_gdt(&real_mode_gdt); 381 382 /* Load the data segment registers, and thus the descriptors ready for 383 real mode. The base address of each segment is 0x100, 16 times the 384 selector value being loaded here. This is so that the segment 385 registers don't have to be reloaded after switching to real mode: 386 the values are consistent for real mode operation already. */ 387 __asm__ __volatile__ ("movl $0x0010,%%eax\n" 388 "\tmovl %%eax,%%ds\n" 389 "\tmovl %%eax,%%es\n" 390 "\tmovl %%eax,%%fs\n" 391 "\tmovl %%eax,%%gs\n" 392 "\tmovl %%eax,%%ss" : : : "eax"); 393 394 /* Jump to the 16-bit code that we copied earlier. It disables paging 395 and the cache, switches to real mode, and jumps to the BIOS reset 396 entry point. */ 397 __asm__ __volatile__ ("ljmp $0x0008,%0" 398 : 399 : "i" ((void *)(0x1000 - sizeof (real_mode_switch) - 100))); 400 } 401 #ifdef CONFIG_APM_MODULE 402 EXPORT_SYMBOL(machine_real_restart); 403 #endif 404 405 #endif /* CONFIG_X86_32 */ 406 407 static inline void kb_wait(void) 408 { 409 int i; 410 411 for (i = 0; i < 0x10000; i++) { 412 if ((inb(0x64) & 0x02) == 0) 413 break; 414 udelay(2); 415 } 416 } 417 418 static void vmxoff_nmi(int cpu, struct die_args *args) 419 { 420 cpu_emergency_vmxoff(); 421 } 422 423 /* Use NMIs as IPIs to tell all CPUs to disable virtualization 424 */ 425 static void emergency_vmx_disable_all(void) 426 { 427 /* Just make sure we won't change CPUs while doing this */ 428 local_irq_disable(); 429 430 /* We need to disable VMX on all CPUs before rebooting, otherwise 431 * we risk hanging up the machine, because the CPU ignore INIT 432 * signals when VMX is enabled. 433 * 434 * We can't take any locks and we may be on an inconsistent 435 * state, so we use NMIs as IPIs to tell the other CPUs to disable 436 * VMX and halt. 437 * 438 * For safety, we will avoid running the nmi_shootdown_cpus() 439 * stuff unnecessarily, but we don't have a way to check 440 * if other CPUs have VMX enabled. So we will call it only if the 441 * CPU we are running on has VMX enabled. 442 * 443 * We will miss cases where VMX is not enabled on all CPUs. This 444 * shouldn't do much harm because KVM always enable VMX on all 445 * CPUs anyway. But we can miss it on the small window where KVM 446 * is still enabling VMX. 447 */ 448 if (cpu_has_vmx() && cpu_vmx_enabled()) { 449 /* Disable VMX on this CPU. 450 */ 451 cpu_vmxoff(); 452 453 /* Halt and disable VMX on the other CPUs */ 454 nmi_shootdown_cpus(vmxoff_nmi); 455 456 } 457 } 458 459 460 void __attribute__((weak)) mach_reboot_fixups(void) 461 { 462 } 463 464 static void native_machine_emergency_restart(void) 465 { 466 int i; 467 468 if (reboot_emergency) 469 emergency_vmx_disable_all(); 470 471 /* Tell the BIOS if we want cold or warm reboot */ 472 *((unsigned short *)__va(0x472)) = reboot_mode; 473 474 for (;;) { 475 /* Could also try the reset bit in the Hammer NB */ 476 switch (reboot_type) { 477 case BOOT_KBD: 478 mach_reboot_fixups(); /* for board specific fixups */ 479 480 for (i = 0; i < 10; i++) { 481 kb_wait(); 482 udelay(50); 483 outb(0xfe, 0x64); /* pulse reset low */ 484 udelay(50); 485 } 486 487 case BOOT_TRIPLE: 488 load_idt(&no_idt); 489 __asm__ __volatile__("int3"); 490 491 reboot_type = BOOT_KBD; 492 break; 493 494 #ifdef CONFIG_X86_32 495 case BOOT_BIOS: 496 machine_real_restart(jump_to_bios, sizeof(jump_to_bios)); 497 498 reboot_type = BOOT_KBD; 499 break; 500 #endif 501 502 case BOOT_ACPI: 503 acpi_reboot(); 504 reboot_type = BOOT_KBD; 505 break; 506 507 case BOOT_EFI: 508 if (efi_enabled) 509 efi.reset_system(reboot_mode ? 510 EFI_RESET_WARM : 511 EFI_RESET_COLD, 512 EFI_SUCCESS, 0, NULL); 513 reboot_type = BOOT_KBD; 514 break; 515 516 case BOOT_CF9: 517 port_cf9_safe = true; 518 /* fall through */ 519 520 case BOOT_CF9_COND: 521 if (port_cf9_safe) { 522 u8 cf9 = inb(0xcf9) & ~6; 523 outb(cf9|2, 0xcf9); /* Request hard reset */ 524 udelay(50); 525 outb(cf9|6, 0xcf9); /* Actually do the reset */ 526 udelay(50); 527 } 528 reboot_type = BOOT_KBD; 529 break; 530 } 531 } 532 } 533 534 void native_machine_shutdown(void) 535 { 536 /* Stop the cpus and apics */ 537 #ifdef CONFIG_SMP 538 539 /* The boot cpu is always logical cpu 0 */ 540 int reboot_cpu_id = 0; 541 542 #ifdef CONFIG_X86_32 543 /* See if there has been given a command line override */ 544 if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && 545 cpu_online(reboot_cpu)) 546 reboot_cpu_id = reboot_cpu; 547 #endif 548 549 /* Make certain the cpu I'm about to reboot on is online */ 550 if (!cpu_online(reboot_cpu_id)) 551 reboot_cpu_id = smp_processor_id(); 552 553 /* Make certain I only run on the appropriate processor */ 554 set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); 555 556 /* O.K Now that I'm on the appropriate processor, 557 * stop all of the others. 558 */ 559 smp_send_stop(); 560 #endif 561 562 lapic_shutdown(); 563 564 #ifdef CONFIG_X86_IO_APIC 565 disable_IO_APIC(); 566 #endif 567 568 #ifdef CONFIG_HPET_TIMER 569 hpet_disable(); 570 #endif 571 572 #ifdef CONFIG_X86_64 573 pci_iommu_shutdown(); 574 #endif 575 } 576 577 static void __machine_emergency_restart(int emergency) 578 { 579 reboot_emergency = emergency; 580 machine_ops.emergency_restart(); 581 } 582 583 static void native_machine_restart(char *__unused) 584 { 585 printk("machine restart\n"); 586 587 if (!reboot_force) 588 machine_shutdown(); 589 __machine_emergency_restart(0); 590 } 591 592 static void native_machine_halt(void) 593 { 594 /* stop other cpus and apics */ 595 machine_shutdown(); 596 597 /* stop this cpu */ 598 stop_this_cpu(NULL); 599 } 600 601 static void native_machine_power_off(void) 602 { 603 if (pm_power_off) { 604 if (!reboot_force) 605 machine_shutdown(); 606 pm_power_off(); 607 } 608 } 609 610 struct machine_ops machine_ops = { 611 .power_off = native_machine_power_off, 612 .shutdown = native_machine_shutdown, 613 .emergency_restart = native_machine_emergency_restart, 614 .restart = native_machine_restart, 615 .halt = native_machine_halt, 616 #ifdef CONFIG_KEXEC 617 .crash_shutdown = native_machine_crash_shutdown, 618 #endif 619 }; 620 621 void machine_power_off(void) 622 { 623 machine_ops.power_off(); 624 } 625 626 void machine_shutdown(void) 627 { 628 machine_ops.shutdown(); 629 } 630 631 void machine_emergency_restart(void) 632 { 633 __machine_emergency_restart(1); 634 } 635 636 void machine_restart(char *cmd) 637 { 638 machine_ops.restart(cmd); 639 } 640 641 void machine_halt(void) 642 { 643 machine_ops.halt(); 644 } 645 646 #ifdef CONFIG_KEXEC 647 void machine_crash_shutdown(struct pt_regs *regs) 648 { 649 machine_ops.crash_shutdown(regs); 650 } 651 #endif 652 653 654 #if defined(CONFIG_SMP) 655 656 /* This keeps a track of which one is crashing cpu. */ 657 static int crashing_cpu; 658 static nmi_shootdown_cb shootdown_callback; 659 660 static atomic_t waiting_for_crash_ipi; 661 662 static int crash_nmi_callback(struct notifier_block *self, 663 unsigned long val, void *data) 664 { 665 int cpu; 666 667 if (val != DIE_NMI_IPI) 668 return NOTIFY_OK; 669 670 cpu = raw_smp_processor_id(); 671 672 /* Don't do anything if this handler is invoked on crashing cpu. 673 * Otherwise, system will completely hang. Crashing cpu can get 674 * an NMI if system was initially booted with nmi_watchdog parameter. 675 */ 676 if (cpu == crashing_cpu) 677 return NOTIFY_STOP; 678 local_irq_disable(); 679 680 shootdown_callback(cpu, (struct die_args *)data); 681 682 atomic_dec(&waiting_for_crash_ipi); 683 /* Assume hlt works */ 684 halt(); 685 for (;;) 686 cpu_relax(); 687 688 return 1; 689 } 690 691 static void smp_send_nmi_allbutself(void) 692 { 693 apic->send_IPI_allbutself(NMI_VECTOR); 694 } 695 696 static struct notifier_block crash_nmi_nb = { 697 .notifier_call = crash_nmi_callback, 698 }; 699 700 /* Halt all other CPUs, calling the specified function on each of them 701 * 702 * This function can be used to halt all other CPUs on crash 703 * or emergency reboot time. The function passed as parameter 704 * will be called inside a NMI handler on all CPUs. 705 */ 706 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 707 { 708 unsigned long msecs; 709 local_irq_disable(); 710 711 /* Make a note of crashing cpu. Will be used in NMI callback.*/ 712 crashing_cpu = safe_smp_processor_id(); 713 714 shootdown_callback = callback; 715 716 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 717 /* Would it be better to replace the trap vector here? */ 718 if (register_die_notifier(&crash_nmi_nb)) 719 return; /* return what? */ 720 /* Ensure the new callback function is set before sending 721 * out the NMI 722 */ 723 wmb(); 724 725 smp_send_nmi_allbutself(); 726 727 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 728 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 729 mdelay(1); 730 msecs--; 731 } 732 733 /* Leave the nmi callback set */ 734 } 735 #else /* !CONFIG_SMP */ 736 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 737 { 738 /* No other CPUs to shoot down */ 739 } 740 #endif 741