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 <acpi/reboot.h> 8 #include <asm/io.h> 9 #include <asm/apic.h> 10 #include <asm/desc.h> 11 #include <asm/hpet.h> 12 #include <asm/pgtable.h> 13 #include <asm/proto.h> 14 #include <asm/reboot_fixups.h> 15 #include <asm/reboot.h> 16 #include <asm/pci_x86.h> 17 #include <asm/virtext.h> 18 #include <asm/cpu.h> 19 20 #ifdef CONFIG_X86_32 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 /* 408 * Apple MacBook5,2 (2009 MacBook) needs reboot=p 409 */ 410 static int __init set_pci_reboot(const struct dmi_system_id *d) 411 { 412 if (reboot_type != BOOT_CF9) { 413 reboot_type = BOOT_CF9; 414 printk(KERN_INFO "%s series board detected. " 415 "Selecting PCI-method for reboots.\n", d->ident); 416 } 417 return 0; 418 } 419 420 static struct dmi_system_id __initdata pci_reboot_dmi_table[] = { 421 { /* Handle problems with rebooting on Apple MacBook5,2 */ 422 .callback = set_pci_reboot, 423 .ident = "Apple MacBook", 424 .matches = { 425 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 426 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5,2"), 427 }, 428 }, 429 { } 430 }; 431 432 static int __init pci_reboot_init(void) 433 { 434 dmi_check_system(pci_reboot_dmi_table); 435 return 0; 436 } 437 core_initcall(pci_reboot_init); 438 439 static inline void kb_wait(void) 440 { 441 int i; 442 443 for (i = 0; i < 0x10000; i++) { 444 if ((inb(0x64) & 0x02) == 0) 445 break; 446 udelay(2); 447 } 448 } 449 450 static void vmxoff_nmi(int cpu, struct die_args *args) 451 { 452 cpu_emergency_vmxoff(); 453 } 454 455 /* Use NMIs as IPIs to tell all CPUs to disable virtualization 456 */ 457 static void emergency_vmx_disable_all(void) 458 { 459 /* Just make sure we won't change CPUs while doing this */ 460 local_irq_disable(); 461 462 /* We need to disable VMX on all CPUs before rebooting, otherwise 463 * we risk hanging up the machine, because the CPU ignore INIT 464 * signals when VMX is enabled. 465 * 466 * We can't take any locks and we may be on an inconsistent 467 * state, so we use NMIs as IPIs to tell the other CPUs to disable 468 * VMX and halt. 469 * 470 * For safety, we will avoid running the nmi_shootdown_cpus() 471 * stuff unnecessarily, but we don't have a way to check 472 * if other CPUs have VMX enabled. So we will call it only if the 473 * CPU we are running on has VMX enabled. 474 * 475 * We will miss cases where VMX is not enabled on all CPUs. This 476 * shouldn't do much harm because KVM always enable VMX on all 477 * CPUs anyway. But we can miss it on the small window where KVM 478 * is still enabling VMX. 479 */ 480 if (cpu_has_vmx() && cpu_vmx_enabled()) { 481 /* Disable VMX on this CPU. 482 */ 483 cpu_vmxoff(); 484 485 /* Halt and disable VMX on the other CPUs */ 486 nmi_shootdown_cpus(vmxoff_nmi); 487 488 } 489 } 490 491 492 void __attribute__((weak)) mach_reboot_fixups(void) 493 { 494 } 495 496 static void native_machine_emergency_restart(void) 497 { 498 int i; 499 500 if (reboot_emergency) 501 emergency_vmx_disable_all(); 502 503 /* Tell the BIOS if we want cold or warm reboot */ 504 *((unsigned short *)__va(0x472)) = reboot_mode; 505 506 for (;;) { 507 /* Could also try the reset bit in the Hammer NB */ 508 switch (reboot_type) { 509 case BOOT_KBD: 510 mach_reboot_fixups(); /* for board specific fixups */ 511 512 for (i = 0; i < 10; i++) { 513 kb_wait(); 514 udelay(50); 515 outb(0xfe, 0x64); /* pulse reset low */ 516 udelay(50); 517 } 518 519 case BOOT_TRIPLE: 520 load_idt(&no_idt); 521 __asm__ __volatile__("int3"); 522 523 reboot_type = BOOT_KBD; 524 break; 525 526 #ifdef CONFIG_X86_32 527 case BOOT_BIOS: 528 machine_real_restart(jump_to_bios, sizeof(jump_to_bios)); 529 530 reboot_type = BOOT_KBD; 531 break; 532 #endif 533 534 case BOOT_ACPI: 535 acpi_reboot(); 536 reboot_type = BOOT_KBD; 537 break; 538 539 case BOOT_EFI: 540 if (efi_enabled) 541 efi.reset_system(reboot_mode ? 542 EFI_RESET_WARM : 543 EFI_RESET_COLD, 544 EFI_SUCCESS, 0, NULL); 545 reboot_type = BOOT_KBD; 546 break; 547 548 case BOOT_CF9: 549 port_cf9_safe = true; 550 /* fall through */ 551 552 case BOOT_CF9_COND: 553 if (port_cf9_safe) { 554 u8 cf9 = inb(0xcf9) & ~6; 555 outb(cf9|2, 0xcf9); /* Request hard reset */ 556 udelay(50); 557 outb(cf9|6, 0xcf9); /* Actually do the reset */ 558 udelay(50); 559 } 560 reboot_type = BOOT_KBD; 561 break; 562 } 563 } 564 } 565 566 void native_machine_shutdown(void) 567 { 568 /* Stop the cpus and apics */ 569 #ifdef CONFIG_SMP 570 571 /* The boot cpu is always logical cpu 0 */ 572 int reboot_cpu_id = 0; 573 574 #ifdef CONFIG_X86_32 575 /* See if there has been given a command line override */ 576 if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && 577 cpu_online(reboot_cpu)) 578 reboot_cpu_id = reboot_cpu; 579 #endif 580 581 /* Make certain the cpu I'm about to reboot on is online */ 582 if (!cpu_online(reboot_cpu_id)) 583 reboot_cpu_id = smp_processor_id(); 584 585 /* Make certain I only run on the appropriate processor */ 586 set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); 587 588 /* O.K Now that I'm on the appropriate processor, 589 * stop all of the others. 590 */ 591 smp_send_stop(); 592 #endif 593 594 lapic_shutdown(); 595 596 #ifdef CONFIG_X86_IO_APIC 597 disable_IO_APIC(); 598 #endif 599 600 #ifdef CONFIG_HPET_TIMER 601 hpet_disable(); 602 #endif 603 604 #ifdef CONFIG_X86_64 605 pci_iommu_shutdown(); 606 #endif 607 } 608 609 static void __machine_emergency_restart(int emergency) 610 { 611 reboot_emergency = emergency; 612 machine_ops.emergency_restart(); 613 } 614 615 static void native_machine_restart(char *__unused) 616 { 617 printk("machine restart\n"); 618 619 if (!reboot_force) 620 machine_shutdown(); 621 __machine_emergency_restart(0); 622 } 623 624 static void native_machine_halt(void) 625 { 626 /* stop other cpus and apics */ 627 machine_shutdown(); 628 629 /* stop this cpu */ 630 stop_this_cpu(NULL); 631 } 632 633 static void native_machine_power_off(void) 634 { 635 if (pm_power_off) { 636 if (!reboot_force) 637 machine_shutdown(); 638 pm_power_off(); 639 } 640 } 641 642 struct machine_ops machine_ops = { 643 .power_off = native_machine_power_off, 644 .shutdown = native_machine_shutdown, 645 .emergency_restart = native_machine_emergency_restart, 646 .restart = native_machine_restart, 647 .halt = native_machine_halt, 648 #ifdef CONFIG_KEXEC 649 .crash_shutdown = native_machine_crash_shutdown, 650 #endif 651 }; 652 653 void machine_power_off(void) 654 { 655 machine_ops.power_off(); 656 } 657 658 void machine_shutdown(void) 659 { 660 machine_ops.shutdown(); 661 } 662 663 void machine_emergency_restart(void) 664 { 665 __machine_emergency_restart(1); 666 } 667 668 void machine_restart(char *cmd) 669 { 670 machine_ops.restart(cmd); 671 } 672 673 void machine_halt(void) 674 { 675 machine_ops.halt(); 676 } 677 678 #ifdef CONFIG_KEXEC 679 void machine_crash_shutdown(struct pt_regs *regs) 680 { 681 machine_ops.crash_shutdown(regs); 682 } 683 #endif 684 685 686 #if defined(CONFIG_SMP) 687 688 /* This keeps a track of which one is crashing cpu. */ 689 static int crashing_cpu; 690 static nmi_shootdown_cb shootdown_callback; 691 692 static atomic_t waiting_for_crash_ipi; 693 694 static int crash_nmi_callback(struct notifier_block *self, 695 unsigned long val, void *data) 696 { 697 int cpu; 698 699 if (val != DIE_NMI_IPI) 700 return NOTIFY_OK; 701 702 cpu = raw_smp_processor_id(); 703 704 /* Don't do anything if this handler is invoked on crashing cpu. 705 * Otherwise, system will completely hang. Crashing cpu can get 706 * an NMI if system was initially booted with nmi_watchdog parameter. 707 */ 708 if (cpu == crashing_cpu) 709 return NOTIFY_STOP; 710 local_irq_disable(); 711 712 shootdown_callback(cpu, (struct die_args *)data); 713 714 atomic_dec(&waiting_for_crash_ipi); 715 /* Assume hlt works */ 716 halt(); 717 for (;;) 718 cpu_relax(); 719 720 return 1; 721 } 722 723 static void smp_send_nmi_allbutself(void) 724 { 725 apic->send_IPI_allbutself(NMI_VECTOR); 726 } 727 728 static struct notifier_block crash_nmi_nb = { 729 .notifier_call = crash_nmi_callback, 730 }; 731 732 /* Halt all other CPUs, calling the specified function on each of them 733 * 734 * This function can be used to halt all other CPUs on crash 735 * or emergency reboot time. The function passed as parameter 736 * will be called inside a NMI handler on all CPUs. 737 */ 738 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 739 { 740 unsigned long msecs; 741 local_irq_disable(); 742 743 /* Make a note of crashing cpu. Will be used in NMI callback.*/ 744 crashing_cpu = safe_smp_processor_id(); 745 746 shootdown_callback = callback; 747 748 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 749 /* Would it be better to replace the trap vector here? */ 750 if (register_die_notifier(&crash_nmi_nb)) 751 return; /* return what? */ 752 /* Ensure the new callback function is set before sending 753 * out the NMI 754 */ 755 wmb(); 756 757 smp_send_nmi_allbutself(); 758 759 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 760 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 761 mdelay(1); 762 msecs--; 763 } 764 765 /* Leave the nmi callback set */ 766 } 767 #else /* !CONFIG_SMP */ 768 void nmi_shootdown_cpus(nmi_shootdown_cb callback) 769 { 770 /* No other CPUs to shoot down */ 771 } 772 #endif 773