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
  32 /*
  33  * Power off function, if any
  34  */
  35 void (*pm_power_off)(void);
  36 EXPORT_SYMBOL(pm_power_off);
  37
  38 static const struct desc_ptr no_idt = {};
  39
  40 /*
  41  * This is set if we need to go through the 'emergency' path.
  42  * When machine_emergency_restart() is called, we may be on
  43  * an inconsistent state and won't be able to do a clean cleanup
  44  */
  45 static int reboot_emergency;
  46
  47 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  48 bool port_cf9_safe = false;
  49
  50 /*
  51  * Reboot options and system auto-detection code provided by
  52  * Dell Inc. so their systems "just work". :-)
  53  */
  54
  55 /*
  56  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  57  * this quirk makes that automatic.
  58  */
  59 static int __init set_bios_reboot(const struct dmi_system_id *d)
  60 {
  61         if (reboot_type != BOOT_BIOS) {
  62                 reboot_type = BOOT_BIOS;
  63                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  64                         "BIOS", d->ident);
  65         }
  66         return 0;
  67 }
  68
  69 void __noreturn machine_real_restart(unsigned int type)
  70 {
  71         local_irq_disable();
  72
  73         /*
  74          * Write zero to CMOS register number 0x0f, which the BIOS POST
  75          * routine will recognize as telling it to do a proper reboot.  (Well
  76          * that's what this book in front of me says -- it may only apply to
  77          * the Phoenix BIOS though, it's not clear).  At the same time,
  78          * disable NMIs by setting the top bit in the CMOS address register,
  79          * as we're about to do peculiar things to the CPU.  I'm not sure if
  80          * `outb_p' is needed instead of just `outb'.  Use it to be on the
  81          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
  82          */
  83         spin_lock(&rtc_lock);
  84         CMOS_WRITE(0x00, 0x8f);
  85         spin_unlock(&rtc_lock);
  86
  87         /*
  88          * Switch back to the initial page table.
  89          */
  90 #ifdef CONFIG_X86_32
  91         load_cr3(initial_page_table);
  92 #else
  93         write_cr3(real_mode_header->trampoline_pgd);
  94 #endif
  95
  96         /* Jump to the identity-mapped low memory code */
  97 #ifdef CONFIG_X86_32
  98         asm volatile("jmpl *%0" : :
  99                      "rm" (real_mode_header->machine_real_restart_asm),
 100                      "a" (type));
 101 #else
 102         asm volatile("ljmpl *%0" : :
 103                      "m" (real_mode_header->machine_real_restart_asm),
 104                      "D" (type));
 105 #endif
 106         unreachable();
 107 }
 108 #ifdef CONFIG_APM_MODULE
 109 EXPORT_SYMBOL(machine_real_restart);
 110 #endif
 111
 112 /*
 113  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 114  */
 115 static int __init set_pci_reboot(const struct dmi_system_id *d)
 116 {
 117         if (reboot_type != BOOT_CF9) {
 118                 reboot_type = BOOT_CF9;
 119                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 120                         "PCI", d->ident);
 121         }
 122         return 0;
 123 }
 124
 125 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 126 {
 127         if (reboot_type != BOOT_KBD) {
 128                 reboot_type = BOOT_KBD;
 129                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 130                         "KBD", d->ident);
 131         }
 132         return 0;
 133 }
 134
 135 /*
 136  * This is a single dmi_table handling all reboot quirks.
 137  */
 138 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 139         {       /* Handle problems with rebooting on Dell E520's */
 140                 .callback = set_bios_reboot,
 141                 .ident = "Dell E520",
 142                 .matches = {
 143                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 144                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 145                 },
 146         },
 147         {       /* Handle problems with rebooting on Dell 1300's */
 148                 .callback = set_bios_reboot,
 149                 .ident = "Dell PowerEdge 1300",
 150                 .matches = {
 151                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 152                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 153                 },
 154         },
 155         {       /* Handle problems with rebooting on Dell 300's */
 156                 .callback = set_bios_reboot,
 157                 .ident = "Dell PowerEdge 300",
 158                 .matches = {
 159                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 160                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 161                 },
 162         },
 163         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 164                 .callback = set_bios_reboot,
 165                 .ident = "Dell OptiPlex 745",
 166                 .matches = {
 167                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 168                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 169                 },
 170         },
 171         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 172                 .callback = set_bios_reboot,
 173                 .ident = "Dell OptiPlex 745",
 174                 .matches = {
 175                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 176                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 177                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 178                 },
 179         },
 180         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 181                 .callback = set_bios_reboot,
 182                 .ident = "Dell OptiPlex 745",
 183                 .matches = {
 184                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 185                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 186                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 187                 },
 188         },
 189         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 190                 .callback = set_bios_reboot,
 191                 .ident = "Dell OptiPlex 330",
 192                 .matches = {
 193                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 194                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 195                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 196                 },
 197         },
 198         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 199                 .callback = set_bios_reboot,
 200                 .ident = "Dell OptiPlex 360",
 201                 .matches = {
 202                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 203                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 204                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 205                 },
 206         },
 207         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 208                 .callback = set_bios_reboot,
 209                 .ident = "Dell OptiPlex 760",
 210                 .matches = {
 211                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 212                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 213                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 214                 },
 215         },
 216         {       /* Handle problems with rebooting on Dell 2400's */
 217                 .callback = set_bios_reboot,
 218                 .ident = "Dell PowerEdge 2400",
 219                 .matches = {
 220                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 221                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 222                 },
 223         },
 224         {       /* Handle problems with rebooting on Dell T5400's */
 225                 .callback = set_bios_reboot,
 226                 .ident = "Dell Precision T5400",
 227                 .matches = {
 228                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 229                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 230                 },
 231         },
 232         {       /* Handle problems with rebooting on Dell T7400's */
 233                 .callback = set_bios_reboot,
 234                 .ident = "Dell Precision T7400",
 235                 .matches = {
 236                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 237                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 238                 },
 239         },
 240         {       /* Handle problems with rebooting on HP laptops */
 241                 .callback = set_bios_reboot,
 242                 .ident = "HP Compaq Laptop",
 243                 .matches = {
 244                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 245                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 246                 },
 247         },
 248         {       /* Handle problems with rebooting on Dell XPS710 */
 249                 .callback = set_bios_reboot,
 250                 .ident = "Dell XPS710",
 251                 .matches = {
 252                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 253                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 254                 },
 255         },
 256         {       /* Handle problems with rebooting on Dell DXP061 */
 257                 .callback = set_bios_reboot,
 258                 .ident = "Dell DXP061",
 259                 .matches = {
 260                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 261                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 262                 },
 263         },
 264         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 265                 .callback = set_bios_reboot,
 266                 .ident = "Sony VGN-Z540N",
 267                 .matches = {
 268                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 269                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 270                 },
 271         },
 272         {       /* Handle problems with rebooting on ASUS P4S800 */
 273                 .callback = set_bios_reboot,
 274                 .ident = "ASUS P4S800",
 275                 .matches = {
 276                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 277                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 278                 },
 279         },
 280
 281         {       /* Handle reboot issue on Acer Aspire one */
 282                 .callback = set_kbd_reboot,
 283                 .ident = "Acer Aspire One A110",
 284                 .matches = {
 285                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 286                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 287                 },
 288         },
 289         {       /* Handle problems with rebooting on Apple MacBook5 */
 290                 .callback = set_pci_reboot,
 291                 .ident = "Apple MacBook5",
 292                 .matches = {
 293                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 294                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 295                 },
 296         },
 297         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 298                 .callback = set_pci_reboot,
 299                 .ident = "Apple MacBookPro5",
 300                 .matches = {
 301                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 302                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 303                 },
 304         },
 305         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 306                 .callback = set_pci_reboot,
 307                 .ident = "Apple Macmini3,1",
 308                 .matches = {
 309                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 310                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 311                 },
 312         },
 313         {       /* Handle problems with rebooting on the iMac9,1. */
 314                 .callback = set_pci_reboot,
 315                 .ident = "Apple iMac9,1",
 316                 .matches = {
 317                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 318                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 319                 },
 320         },
 321         {       /* Handle problems with rebooting on the Latitude E6320. */
 322                 .callback = set_pci_reboot,
 323                 .ident = "Dell Latitude E6320",
 324                 .matches = {
 325                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 326                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 327                 },
 328         },
 329         {       /* Handle problems with rebooting on the Latitude E5420. */
 330                 .callback = set_pci_reboot,
 331                 .ident = "Dell Latitude E5420",
 332                 .matches = {
 333                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 334                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 335                 },
 336         },
 337         {       /* Handle problems with rebooting on the Latitude E6420. */
 338                 .callback = set_pci_reboot,
 339                 .ident = "Dell Latitude E6420",
 340                 .matches = {
 341                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 342                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 343                 },
 344         },
 345         {       /* Handle problems with rebooting on the OptiPlex 990. */
 346                 .callback = set_pci_reboot,
 347                 .ident = "Dell OptiPlex 990",
 348                 .matches = {
 349                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 350                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 351                 },
 352         },
 353         {       /* Handle problems with rebooting on the Precision M6600. */
 354                 .callback = set_pci_reboot,
 355                 .ident = "Dell Precision M6600",
 356                 .matches = {
 357                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 358                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 359                 },
 360         },
 361         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 362                 .callback = set_pci_reboot,
 363                 .ident = "Dell PowerEdge C6100",
 364                 .matches = {
 365                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 366                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 367                 },
 368         },
 369         {       /* Some C6100 machines were shipped with vendor being 'Dell'. */
 370                 .callback = set_pci_reboot,
 371                 .ident = "Dell PowerEdge C6100",
 372                 .matches = {
 373                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 374                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 375                 },
 376         },
 377         { }
 378 };
 379
 380 static int __init reboot_init(void)
 381 {
 382         /*
 383          * Only do the DMI check if reboot_type hasn't been overridden
 384          * on the command line
 385          */
 386         if (reboot_default)
 387                 dmi_check_system(reboot_dmi_table);
 388         return 0;
 389 }
 390 core_initcall(reboot_init);
 391
 392 static inline void kb_wait(void)
 393 {
 394         int i;
 395
 396         for (i = 0; i < 0x10000; i++) {
 397                 if ((inb(0x64) & 0x02) == 0)
 398                         break;
 399                 udelay(2);
 400         }
 401 }
 402
 403 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 404 {
 405         cpu_emergency_vmxoff();
 406 }
 407
 408 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 409 static void emergency_vmx_disable_all(void)
 410 {
 411         /* Just make sure we won't change CPUs while doing this */
 412         local_irq_disable();
 413
 414         /*
 415          * We need to disable VMX on all CPUs before rebooting, otherwise
 416          * we risk hanging up the machine, because the CPU ignore INIT
 417          * signals when VMX is enabled.
 418          *
 419          * We can't take any locks and we may be on an inconsistent
 420          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 421          * VMX and halt.
 422          *
 423          * For safety, we will avoid running the nmi_shootdown_cpus()
 424          * stuff unnecessarily, but we don't have a way to check
 425          * if other CPUs have VMX enabled. So we will call it only if the
 426          * CPU we are running on has VMX enabled.
 427          *
 428          * We will miss cases where VMX is not enabled on all CPUs. This
 429          * shouldn't do much harm because KVM always enable VMX on all
 430          * CPUs anyway. But we can miss it on the small window where KVM
 431          * is still enabling VMX.
 432          */
 433         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 434                 /* Disable VMX on this CPU. */
 435                 cpu_vmxoff();
 436
 437                 /* Halt and disable VMX on the other CPUs */
 438                 nmi_shootdown_cpus(vmxoff_nmi);
 439
 440         }
 441 }
 442
 443
 444 void __attribute__((weak)) mach_reboot_fixups(void)
 445 {
 446 }
 447
 448 /*
 449  * Windows compatible x86 hardware expects the following on reboot:
 450  *
 451  * 1) If the FADT has the ACPI reboot register flag set, try it
 452  * 2) If still alive, write to the keyboard controller
 453  * 3) If still alive, write to the ACPI reboot register again
 454  * 4) If still alive, write to the keyboard controller again
 455  *
 456  * If the machine is still alive at this stage, it gives up. We default to
 457  * following the same pattern, except that if we're still alive after (4) we'll
 458  * try to force a triple fault and then cycle between hitting the keyboard
 459  * controller and doing that
 460  */
 461 static void native_machine_emergency_restart(void)
 462 {
 463         int i;
 464         int attempt = 0;
 465         int orig_reboot_type = reboot_type;
 466         unsigned short mode;
 467
 468         if (reboot_emergency)
 469                 emergency_vmx_disable_all();
 470
 471         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 472
 473         /* Tell the BIOS if we want cold or warm reboot */
 474         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 475         *((unsigned short *)__va(0x472)) = mode;
 476
 477         for (;;) {
 478                 /* Could also try the reset bit in the Hammer NB */
 479                 switch (reboot_type) {
 480                 case BOOT_KBD:
 481                         mach_reboot_fixups(); /* For board specific fixups */
 482
 483                         for (i = 0; i < 10; i++) {
 484                                 kb_wait();
 485                                 udelay(50);
 486                                 outb(0xfe, 0x64); /* Pulse reset low */
 487                                 udelay(50);
 488                         }
 489                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 490                                 attempt = 1;
 491                                 reboot_type = BOOT_ACPI;
 492                         } else {
 493                                 reboot_type = BOOT_TRIPLE;
 494                         }
 495                         break;
 496
 497                 case BOOT_TRIPLE:
 498                         load_idt(&no_idt);
 499                         __asm__ __volatile__("int3");
 500
 501                         reboot_type = BOOT_KBD;
 502                         break;
 503
 504                 case BOOT_BIOS:
 505                         machine_real_restart(MRR_BIOS);
 506
 507                         reboot_type = BOOT_KBD;
 508                         break;
 509
 510                 case BOOT_ACPI:
 511                         acpi_reboot();
 512                         reboot_type = BOOT_KBD;
 513                         break;
 514
 515                 case BOOT_EFI:
 516                         if (efi_enabled(EFI_RUNTIME_SERVICES))
 517                                 efi.reset_system(reboot_mode == REBOOT_WARM ?
 518                                                  EFI_RESET_WARM :
 519                                                  EFI_RESET_COLD,
 520                                                  EFI_SUCCESS, 0, NULL);
 521                         reboot_type = BOOT_KBD;
 522                         break;
 523
 524                 case BOOT_CF9:
 525                         port_cf9_safe = true;
 526                         /* Fall through */
 527
 528                 case BOOT_CF9_COND:
 529                         if (port_cf9_safe) {
 530                                 u8 cf9 = inb(0xcf9) & ~6;
 531                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 532                                 udelay(50);
 533                                 outb(cf9|6, 0xcf9); /* Actually do the reset */
 534                                 udelay(50);
 535                         }
 536                         reboot_type = BOOT_KBD;
 537                         break;
 538                 }
 539         }
 540 }
 541
 542 void native_machine_shutdown(void)
 543 {
 544         /* Stop the cpus and apics */
 545 #ifdef CONFIG_SMP
 546         /*
 547          * Stop all of the others. Also disable the local irq to
 548          * not receive the per-cpu timer interrupt which may trigger
 549          * scheduler's load balance.
 550          */
 551         local_irq_disable();
 552         stop_other_cpus();
 553 #endif
 554
 555         lapic_shutdown();
 556
 557 #ifdef CONFIG_X86_IO_APIC
 558         disable_IO_APIC();
 559 #endif
 560
 561 #ifdef CONFIG_HPET_TIMER
 562         hpet_disable();
 563 #endif
 564
 565 #ifdef CONFIG_X86_64
 566         x86_platform.iommu_shutdown();
 567 #endif
 568 }
 569
 570 static void __machine_emergency_restart(int emergency)
 571 {
 572         reboot_emergency = emergency;
 573         machine_ops.emergency_restart();
 574 }
 575
 576 static void native_machine_restart(char *__unused)
 577 {
 578         pr_notice("machine restart\n");
 579
 580         if (!reboot_force)
 581                 machine_shutdown();
 582         __machine_emergency_restart(0);
 583 }
 584
 585 static void native_machine_halt(void)
 586 {
 587         /* Stop other cpus and apics */
 588         machine_shutdown();
 589
 590         tboot_shutdown(TB_SHUTDOWN_HALT);
 591
 592         stop_this_cpu(NULL);
 593 }
 594
 595 static void native_machine_power_off(void)
 596 {
 597         if (pm_power_off) {
 598                 if (!reboot_force)
 599                         machine_shutdown();
 600                 pm_power_off();
 601         }
 602         /* A fallback in case there is no PM info available */
 603         tboot_shutdown(TB_SHUTDOWN_HALT);
 604 }
 605
 606 struct machine_ops machine_ops = {
 607         .power_off = native_machine_power_off,
 608         .shutdown = native_machine_shutdown,
 609         .emergency_restart = native_machine_emergency_restart,
 610         .restart = native_machine_restart,
 611         .halt = native_machine_halt,
 612 #ifdef CONFIG_KEXEC
 613         .crash_shutdown = native_machine_crash_shutdown,
 614 #endif
 615 };
 616
 617 void machine_power_off(void)
 618 {
 619         machine_ops.power_off();
 620 }
 621
 622 void machine_shutdown(void)
 623 {
 624         machine_ops.shutdown();
 625 }
 626
 627 void machine_emergency_restart(void)
 628 {
 629         __machine_emergency_restart(1);
 630 }
 631
 632 void machine_restart(char *cmd)
 633 {
 634         machine_ops.restart(cmd);
 635 }
 636
 637 void machine_halt(void)
 638 {
 639         machine_ops.halt();
 640 }
 641
 642 #ifdef CONFIG_KEXEC
 643 void machine_crash_shutdown(struct pt_regs *regs)
 644 {
 645         machine_ops.crash_shutdown(regs);
 646 }
 647 #endif
 648
 649
 650 #if defined(CONFIG_SMP)
 651
 652 /* This keeps a track of which one is crashing cpu. */
 653 static int crashing_cpu;
 654 static nmi_shootdown_cb shootdown_callback;
 655
 656 static atomic_t waiting_for_crash_ipi;
 657
 658 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 659 {
 660         int cpu;
 661
 662         cpu = raw_smp_processor_id();
 663
 664         /*
 665          * Don't do anything if this handler is invoked on crashing cpu.
 666          * Otherwise, system will completely hang. Crashing cpu can get
 667          * an NMI if system was initially booted with nmi_watchdog parameter.
 668          */
 669         if (cpu == crashing_cpu)
 670                 return NMI_HANDLED;
 671         local_irq_disable();
 672
 673         shootdown_callback(cpu, regs);
 674
 675         atomic_dec(&waiting_for_crash_ipi);
 676         /* Assume hlt works */
 677         halt();
 678         for (;;)
 679                 cpu_relax();
 680
 681         return NMI_HANDLED;
 682 }
 683
 684 static void smp_send_nmi_allbutself(void)
 685 {
 686         apic->send_IPI_allbutself(NMI_VECTOR);
 687 }
 688
 689 /*
 690  * Halt all other CPUs, calling the specified function on each of them
 691  *
 692  * This function can be used to halt all other CPUs on crash
 693  * or emergency reboot time. The function passed as parameter
 694  * will be called inside a NMI handler on all CPUs.
 695  */
 696 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 697 {
 698         unsigned long msecs;
 699         local_irq_disable();
 700
 701         /* Make a note of crashing cpu. Will be used in NMI callback. */
 702         crashing_cpu = safe_smp_processor_id();
 703
 704         shootdown_callback = callback;
 705
 706         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 707         /* Would it be better to replace the trap vector here? */
 708         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 709                                  NMI_FLAG_FIRST, "crash"))
 710                 return;         /* Return what? */
 711         /*
 712          * Ensure the new callback function is set before sending
 713          * out the NMI
 714          */
 715         wmb();
 716
 717         smp_send_nmi_allbutself();
 718
 719         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 720         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 721                 mdelay(1);
 722                 msecs--;
 723         }
 724
 725         /* Leave the nmi callback set */
 726 }
 727 #else /* !CONFIG_SMP */
 728 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 729 {
 730         /* No other CPUs to shoot down */
 731 }
 732 #endif