arch/x86/kernel/reboot.c

   1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   2
   3 #include <linux/module.h>
   4 #include <linux/reboot.h>
   5 #include <linux/init.h>
   6 #include <linux/pm.h>
   7 #include <linux/efi.h>
   8 #include <linux/dmi.h>
   9 #include <linux/sched.h>
  10 #include <linux/tboot.h>
  11 #include <linux/delay.h>
  12 #include <acpi/reboot.h>
  13 #include <asm/io.h>
  14 #include <asm/apic.h>
  15 #include <asm/desc.h>
  16 #include <asm/hpet.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/proto.h>
  19 #include <asm/reboot_fixups.h>
  20 #include <asm/reboot.h>
  21 #include <asm/pci_x86.h>
  22 #include <asm/virtext.h>
  23 #include <asm/cpu.h>
  24 #include <asm/nmi.h>
  25 #include <asm/smp.h>
  26
  27 #include <linux/ctype.h>
  28 #include <linux/mc146818rtc.h>
  29 #include <asm/realmode.h>
  30 #include <asm/x86_init.h>
  31 #include <asm/efi.h>
  32
  33 /*
  34  * Power off function, if any
  35  */
  36 void (*pm_power_off)(void);
  37 EXPORT_SYMBOL(pm_power_off);
  38
  39 static const struct desc_ptr no_idt = {};
  40
  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 /*
  52  * Reboot options and system auto-detection code provided by
  53  * Dell Inc. so their systems "just work". :-)
  54  */
  55
  56 /*
  57  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  58  * this quirk makes that automatic.
  59  */
  60 static int __init set_bios_reboot(const struct dmi_system_id *d)
  61 {
  62         if (reboot_type != BOOT_BIOS) {
  63                 reboot_type = BOOT_BIOS;
  64                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  65                         d->ident, "BIOS");
  66         }
  67         return 0;
  68 }
  69
  70 void __noreturn machine_real_restart(unsigned int type)
  71 {
  72         local_irq_disable();
  73
  74         /*
  75          * Write zero to CMOS register number 0x0f, which the BIOS POST
  76          * routine will recognize as telling it to do a proper reboot.  (Well
  77          * that's what this book in front of me says -- it may only apply to
  78          * the Phoenix BIOS though, it's not clear).  At the same time,
  79          * disable NMIs by setting the top bit in the CMOS address register,
  80          * as we're about to do peculiar things to the CPU.  I'm not sure if
  81          * `outb_p' is needed instead of just `outb'.  Use it to be on the
  82          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
  83          */
  84         spin_lock(&rtc_lock);
  85         CMOS_WRITE(0x00, 0x8f);
  86         spin_unlock(&rtc_lock);
  87
  88         /*
  89          * Switch back to the initial page table.
  90          */
  91 #ifdef CONFIG_X86_32
  92         load_cr3(initial_page_table);
  93 #else
  94         write_cr3(real_mode_header->trampoline_pgd);
  95 #endif
  96
  97         /* Jump to the identity-mapped low memory code */
  98 #ifdef CONFIG_X86_32
  99         asm volatile("jmpl *%0" : :
 100                      "rm" (real_mode_header->machine_real_restart_asm),
 101                      "a" (type));
 102 #else
 103         asm volatile("ljmpl *%0" : :
 104                      "m" (real_mode_header->machine_real_restart_asm),
 105                      "D" (type));
 106 #endif
 107         unreachable();
 108 }
 109 #ifdef CONFIG_APM_MODULE
 110 EXPORT_SYMBOL(machine_real_restart);
 111 #endif
 112
 113 /*
 114  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 115  */
 116 static int __init set_pci_reboot(const struct dmi_system_id *d)
 117 {
 118         if (reboot_type != BOOT_CF9_FORCE) {
 119                 reboot_type = BOOT_CF9_FORCE;
 120                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 121                         d->ident, "PCI");
 122         }
 123         return 0;
 124 }
 125
 126 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 127 {
 128         if (reboot_type != BOOT_KBD) {
 129                 reboot_type = BOOT_KBD;
 130                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 131                         d->ident, "KBD");
 132         }
 133         return 0;
 134 }
 135
 136 /*
 137  * This is a single dmi_table handling all reboot quirks.
 138  */
 139 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 140
 141         /* Acer */
 142         {       /* Handle reboot issue on Acer Aspire one */
 143                 .callback = set_kbd_reboot,
 144                 .ident = "Acer Aspire One A110",
 145                 .matches = {
 146                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 147                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 148                 },
 149         },
 150
 151         /* Apple */
 152         {       /* Handle problems with rebooting on Apple MacBook5 */
 153                 .callback = set_pci_reboot,
 154                 .ident = "Apple MacBook5",
 155                 .matches = {
 156                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 157                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 158                 },
 159         },
 160         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 161                 .callback = set_pci_reboot,
 162                 .ident = "Apple MacBookPro5",
 163                 .matches = {
 164                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 165                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 166                 },
 167         },
 168         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 169                 .callback = set_pci_reboot,
 170                 .ident = "Apple Macmini3,1",
 171                 .matches = {
 172                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 173                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 174                 },
 175         },
 176         {       /* Handle problems with rebooting on the iMac9,1. */
 177                 .callback = set_pci_reboot,
 178                 .ident = "Apple iMac9,1",
 179                 .matches = {
 180                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 181                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 182                 },
 183         },
 184
 185         /* ASUS */
 186         {       /* Handle problems with rebooting on ASUS P4S800 */
 187                 .callback = set_bios_reboot,
 188                 .ident = "ASUS P4S800",
 189                 .matches = {
 190                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 191                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 192                 },
 193         },
 194
 195         /* Certec */
 196         {       /* Handle problems with rebooting on Certec BPC600 */
 197                 .callback = set_pci_reboot,
 198                 .ident = "Certec BPC600",
 199                 .matches = {
 200                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 201                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 202                 },
 203         },
 204
 205         /* Dell */
 206         {       /* Handle problems with rebooting on Dell DXP061 */
 207                 .callback = set_bios_reboot,
 208                 .ident = "Dell DXP061",
 209                 .matches = {
 210                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 211                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 212                 },
 213         },
 214         {       /* Handle problems with rebooting on Dell E520's */
 215                 .callback = set_bios_reboot,
 216                 .ident = "Dell E520",
 217                 .matches = {
 218                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 219                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 220                 },
 221         },
 222         {       /* Handle problems with rebooting on the Latitude E5410. */
 223                 .callback = set_pci_reboot,
 224                 .ident = "Dell Latitude E5410",
 225                 .matches = {
 226                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 227                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 228                 },
 229         },
 230         {       /* Handle problems with rebooting on the Latitude E5420. */
 231                 .callback = set_pci_reboot,
 232                 .ident = "Dell Latitude E5420",
 233                 .matches = {
 234                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 235                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 236                 },
 237         },
 238         {       /* Handle problems with rebooting on the Latitude E6320. */
 239                 .callback = set_pci_reboot,
 240                 .ident = "Dell Latitude E6320",
 241                 .matches = {
 242                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 243                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 244                 },
 245         },
 246         {       /* Handle problems with rebooting on the Latitude E6420. */
 247                 .callback = set_pci_reboot,
 248                 .ident = "Dell Latitude E6420",
 249                 .matches = {
 250                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 251                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 252                 },
 253         },
 254         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 255                 .callback = set_bios_reboot,
 256                 .ident = "Dell OptiPlex 330",
 257                 .matches = {
 258                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 259                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 260                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 261                 },
 262         },
 263         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 264                 .callback = set_bios_reboot,
 265                 .ident = "Dell OptiPlex 360",
 266                 .matches = {
 267                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 268                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 269                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 270                 },
 271         },
 272         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 273                 .callback = set_bios_reboot,
 274                 .ident = "Dell OptiPlex 745",
 275                 .matches = {
 276                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 277                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 278                 },
 279         },
 280         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 281                 .callback = set_bios_reboot,
 282                 .ident = "Dell OptiPlex 745",
 283                 .matches = {
 284                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 285                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 286                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 287                 },
 288         },
 289         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 290                 .callback = set_bios_reboot,
 291                 .ident = "Dell OptiPlex 745",
 292                 .matches = {
 293                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 294                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 295                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 296                 },
 297         },
 298         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 299                 .callback = set_bios_reboot,
 300                 .ident = "Dell OptiPlex 760",
 301                 .matches = {
 302                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 303                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 304                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 305                 },
 306         },
 307         {       /* Handle problems with rebooting on the OptiPlex 990. */
 308                 .callback = set_pci_reboot,
 309                 .ident = "Dell OptiPlex 990",
 310                 .matches = {
 311                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 312                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 313                 },
 314         },
 315         {       /* Handle problems with rebooting on Dell 300's */
 316                 .callback = set_bios_reboot,
 317                 .ident = "Dell PowerEdge 300",
 318                 .matches = {
 319                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 320                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 321                 },
 322         },
 323         {       /* Handle problems with rebooting on Dell 1300's */
 324                 .callback = set_bios_reboot,
 325                 .ident = "Dell PowerEdge 1300",
 326                 .matches = {
 327                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 328                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 329                 },
 330         },
 331         {       /* Handle problems with rebooting on Dell 2400's */
 332                 .callback = set_bios_reboot,
 333                 .ident = "Dell PowerEdge 2400",
 334                 .matches = {
 335                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 336                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 337                 },
 338         },
 339         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 340                 .callback = set_pci_reboot,
 341                 .ident = "Dell PowerEdge C6100",
 342                 .matches = {
 343                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 344                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 345                 },
 346         },
 347         {       /* Handle problems with rebooting on the Precision M6600. */
 348                 .callback = set_pci_reboot,
 349                 .ident = "Dell Precision M6600",
 350                 .matches = {
 351                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 352                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 353                 },
 354         },
 355         {       /* Handle problems with rebooting on Dell T5400's */
 356                 .callback = set_bios_reboot,
 357                 .ident = "Dell Precision T5400",
 358                 .matches = {
 359                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 360                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 361                 },
 362         },
 363         {       /* Handle problems with rebooting on Dell T7400's */
 364                 .callback = set_bios_reboot,
 365                 .ident = "Dell Precision T7400",
 366                 .matches = {
 367                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 368                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 369                 },
 370         },
 371         {       /* Handle problems with rebooting on Dell XPS710 */
 372                 .callback = set_bios_reboot,
 373                 .ident = "Dell XPS710",
 374                 .matches = {
 375                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 376                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 377                 },
 378         },
 379
 380         /* Hewlett-Packard */
 381         {       /* Handle problems with rebooting on HP laptops */
 382                 .callback = set_bios_reboot,
 383                 .ident = "HP Compaq Laptop",
 384                 .matches = {
 385                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 386                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 387                 },
 388         },
 389
 390         /* Sony */
 391         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 392                 .callback = set_bios_reboot,
 393                 .ident = "Sony VGN-Z540N",
 394                 .matches = {
 395                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 396                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 397                 },
 398         },
 399
 400         { }
 401 };
 402
 403 static int __init reboot_init(void)
 404 {
 405         int rv;
 406
 407         /*
 408          * Only do the DMI check if reboot_type hasn't been overridden
 409          * on the command line
 410          */
 411         if (!reboot_default)
 412                 return 0;
 413
 414         /*
 415          * The DMI quirks table takes precedence. If no quirks entry
 416          * matches and the ACPI Hardware Reduced bit is set, force EFI
 417          * reboot.
 418          */
 419         rv = dmi_check_system(reboot_dmi_table);
 420
 421         if (!rv && efi_reboot_required())
 422                 reboot_type = BOOT_EFI;
 423
 424         return 0;
 425 }
 426 core_initcall(reboot_init);
 427
 428 static inline void kb_wait(void)
 429 {
 430         int i;
 431
 432         for (i = 0; i < 0x10000; i++) {
 433                 if ((inb(0x64) & 0x02) == 0)
 434                         break;
 435                 udelay(2);
 436         }
 437 }
 438
 439 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 440 {
 441         cpu_emergency_vmxoff();
 442 }
 443
 444 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 445 static void emergency_vmx_disable_all(void)
 446 {
 447         /* Just make sure we won't change CPUs while doing this */
 448         local_irq_disable();
 449
 450         /*
 451          * We need to disable VMX on all CPUs before rebooting, otherwise
 452          * we risk hanging up the machine, because the CPU ignore INIT
 453          * signals when VMX is enabled.
 454          *
 455          * We can't take any locks and we may be on an inconsistent
 456          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 457          * VMX and halt.
 458          *
 459          * For safety, we will avoid running the nmi_shootdown_cpus()
 460          * stuff unnecessarily, but we don't have a way to check
 461          * if other CPUs have VMX enabled. So we will call it only if the
 462          * CPU we are running on has VMX enabled.
 463          *
 464          * We will miss cases where VMX is not enabled on all CPUs. This
 465          * shouldn't do much harm because KVM always enable VMX on all
 466          * CPUs anyway. But we can miss it on the small window where KVM
 467          * is still enabling VMX.
 468          */
 469         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 470                 /* Disable VMX on this CPU. */
 471                 cpu_vmxoff();
 472
 473                 /* Halt and disable VMX on the other CPUs */
 474                 nmi_shootdown_cpus(vmxoff_nmi);
 475
 476         }
 477 }
 478
 479
 480 void __attribute__((weak)) mach_reboot_fixups(void)
 481 {
 482 }
 483
 484 /*
 485  * To the best of our knowledge Windows compatible x86 hardware expects
 486  * the following on reboot:
 487  *
 488  * 1) If the FADT has the ACPI reboot register flag set, try it
 489  * 2) If still alive, write to the keyboard controller
 490  * 3) If still alive, write to the ACPI reboot register again
 491  * 4) If still alive, write to the keyboard controller again
 492  * 5) If still alive, call the EFI runtime service to reboot
 493  * 6) If no EFI runtime service, call the BIOS to do a reboot
 494  *
 495  * We default to following the same pattern. We also have
 496  * two other reboot methods: 'triple fault' and 'PCI', which
 497  * can be triggered via the reboot= kernel boot option or
 498  * via quirks.
 499  *
 500  * This means that this function can never return, it can misbehave
 501  * by not rebooting properly and hanging.
 502  */
 503 static void native_machine_emergency_restart(void)
 504 {
 505         int i;
 506         int attempt = 0;
 507         int orig_reboot_type = reboot_type;
 508         unsigned short mode;
 509
 510         if (reboot_emergency)
 511                 emergency_vmx_disable_all();
 512
 513         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 514
 515         /* Tell the BIOS if we want cold or warm reboot */
 516         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 517         *((unsigned short *)__va(0x472)) = mode;
 518
 519         for (;;) {
 520                 /* Could also try the reset bit in the Hammer NB */
 521                 switch (reboot_type) {
 522                 case BOOT_ACPI:
 523                         acpi_reboot();
 524                         reboot_type = BOOT_KBD;
 525                         break;
 526
 527                 case BOOT_KBD:
 528                         mach_reboot_fixups(); /* For board specific fixups */
 529
 530                         for (i = 0; i < 10; i++) {
 531                                 kb_wait();
 532                                 udelay(50);
 533                                 outb(0xfe, 0x64); /* Pulse reset low */
 534                                 udelay(50);
 535                         }
 536                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 537                                 attempt = 1;
 538                                 reboot_type = BOOT_ACPI;
 539                         } else {
 540                                 reboot_type = BOOT_EFI;
 541                         }
 542                         break;
 543
 544                 case BOOT_EFI:
 545                         efi_reboot(reboot_mode, NULL);
 546                         reboot_type = BOOT_BIOS;
 547                         break;
 548
 549                 case BOOT_BIOS:
 550                         machine_real_restart(MRR_BIOS);
 551
 552                         /* We're probably dead after this, but... */
 553                         reboot_type = BOOT_CF9_SAFE;
 554                         break;
 555
 556                 case BOOT_CF9_FORCE:
 557                         port_cf9_safe = true;
 558                         /* Fall through */
 559
 560                 case BOOT_CF9_SAFE:
 561                         if (port_cf9_safe) {
 562                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 563                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 564                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 565                                 udelay(50);
 566                                 /* Actually do the reset */
 567                                 outb(cf9|reboot_code, 0xcf9);
 568                                 udelay(50);
 569                         }
 570                         reboot_type = BOOT_TRIPLE;
 571                         break;
 572
 573                 case BOOT_TRIPLE:
 574                         load_idt(&no_idt);
 575                         __asm__ __volatile__("int3");
 576
 577                         /* We're probably dead after this, but... */
 578                         reboot_type = BOOT_KBD;
 579                         break;
 580                 }
 581         }
 582 }
 583
 584 void native_machine_shutdown(void)
 585 {
 586         /* Stop the cpus and apics */
 587 #ifdef CONFIG_X86_IO_APIC
 588         /*
 589          * Disabling IO APIC before local APIC is a workaround for
 590          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 591          * Specification Update". In this situation, interrupts that target
 592          * a Logical Processor whose Local APIC is either in the process of
 593          * being hardware disabled or software disabled are neither delivered
 594          * nor discarded. When this erratum occurs, the processor may hang.
 595          *
 596          * Even without the erratum, it still makes sense to quiet IO APIC
 597          * before disabling Local APIC.
 598          */
 599         disable_IO_APIC();
 600 #endif
 601
 602 #ifdef CONFIG_SMP
 603         /*
 604          * Stop all of the others. Also disable the local irq to
 605          * not receive the per-cpu timer interrupt which may trigger
 606          * scheduler's load balance.
 607          */
 608         local_irq_disable();
 609         stop_other_cpus();
 610 #endif
 611
 612         lapic_shutdown();
 613
 614 #ifdef CONFIG_HPET_TIMER
 615         hpet_disable();
 616 #endif
 617
 618 #ifdef CONFIG_X86_64
 619         x86_platform.iommu_shutdown();
 620 #endif
 621 }
 622
 623 static void __machine_emergency_restart(int emergency)
 624 {
 625         reboot_emergency = emergency;
 626         machine_ops.emergency_restart();
 627 }
 628
 629 static void native_machine_restart(char *__unused)
 630 {
 631         pr_notice("machine restart\n");
 632
 633         if (!reboot_force)
 634                 machine_shutdown();
 635         __machine_emergency_restart(0);
 636 }
 637
 638 static void native_machine_halt(void)
 639 {
 640         /* Stop other cpus and apics */
 641         machine_shutdown();
 642
 643         tboot_shutdown(TB_SHUTDOWN_HALT);
 644
 645         stop_this_cpu(NULL);
 646 }
 647
 648 static void native_machine_power_off(void)
 649 {
 650         if (pm_power_off) {
 651                 if (!reboot_force)
 652                         machine_shutdown();
 653                 pm_power_off();
 654         }
 655         /* A fallback in case there is no PM info available */
 656         tboot_shutdown(TB_SHUTDOWN_HALT);
 657 }
 658
 659 struct machine_ops machine_ops = {
 660         .power_off = native_machine_power_off,
 661         .shutdown = native_machine_shutdown,
 662         .emergency_restart = native_machine_emergency_restart,
 663         .restart = native_machine_restart,
 664         .halt = native_machine_halt,
 665 #ifdef CONFIG_KEXEC
 666         .crash_shutdown = native_machine_crash_shutdown,
 667 #endif
 668 };
 669
 670 void machine_power_off(void)
 671 {
 672         machine_ops.power_off();
 673 }
 674
 675 void machine_shutdown(void)
 676 {
 677         machine_ops.shutdown();
 678 }
 679
 680 void machine_emergency_restart(void)
 681 {
 682         __machine_emergency_restart(1);
 683 }
 684
 685 void machine_restart(char *cmd)
 686 {
 687         machine_ops.restart(cmd);
 688 }
 689
 690 void machine_halt(void)
 691 {
 692         machine_ops.halt();
 693 }
 694
 695 #ifdef CONFIG_KEXEC
 696 void machine_crash_shutdown(struct pt_regs *regs)
 697 {
 698         machine_ops.crash_shutdown(regs);
 699 }
 700 #endif
 701
 702
 703 #if defined(CONFIG_SMP)
 704
 705 /* This keeps a track of which one is crashing cpu. */
 706 static int crashing_cpu;
 707 static nmi_shootdown_cb shootdown_callback;
 708
 709 static atomic_t waiting_for_crash_ipi;
 710
 711 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 712 {
 713         int cpu;
 714
 715         cpu = raw_smp_processor_id();
 716
 717         /*
 718          * Don't do anything if this handler is invoked on crashing cpu.
 719          * Otherwise, system will completely hang. Crashing cpu can get
 720          * an NMI if system was initially booted with nmi_watchdog parameter.
 721          */
 722         if (cpu == crashing_cpu)
 723                 return NMI_HANDLED;
 724         local_irq_disable();
 725
 726         shootdown_callback(cpu, regs);
 727
 728         atomic_dec(&waiting_for_crash_ipi);
 729         /* Assume hlt works */
 730         halt();
 731         for (;;)
 732                 cpu_relax();
 733
 734         return NMI_HANDLED;
 735 }
 736
 737 static void smp_send_nmi_allbutself(void)
 738 {
 739         apic->send_IPI_allbutself(NMI_VECTOR);
 740 }
 741
 742 /*
 743  * Halt all other CPUs, calling the specified function on each of them
 744  *
 745  * This function can be used to halt all other CPUs on crash
 746  * or emergency reboot time. The function passed as parameter
 747  * will be called inside a NMI handler on all CPUs.
 748  */
 749 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 750 {
 751         unsigned long msecs;
 752         local_irq_disable();
 753
 754         /* Make a note of crashing cpu. Will be used in NMI callback. */
 755         crashing_cpu = safe_smp_processor_id();
 756
 757         shootdown_callback = callback;
 758
 759         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 760         /* Would it be better to replace the trap vector here? */
 761         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 762                                  NMI_FLAG_FIRST, "crash"))
 763                 return;         /* Return what? */
 764         /*
 765          * Ensure the new callback function is set before sending
 766          * out the NMI
 767          */
 768         wmb();
 769
 770         smp_send_nmi_allbutself();
 771
 772         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 773         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 774                 mdelay(1);
 775                 msecs--;
 776         }
 777
 778         /* Leave the nmi callback set */
 779 }
 780 #else /* !CONFIG_SMP */
 781 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 782 {
 783         /* No other CPUs to shoot down */
 784 }
 785 #endif