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/io_apic.h>
  16 #include <asm/desc.h>
  17 #include <asm/hpet.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/proto.h>
  20 #include <asm/reboot_fixups.h>
  21 #include <asm/reboot.h>
  22 #include <asm/pci_x86.h>
  23 #include <asm/virtext.h>
  24 #include <asm/cpu.h>
  25 #include <asm/nmi.h>
  26 #include <asm/smp.h>
  27
  28 #include <linux/ctype.h>
  29 #include <linux/mc146818rtc.h>
  30 #include <asm/realmode.h>
  31 #include <asm/x86_init.h>
  32 #include <asm/efi.h>
  33
  34 /*
  35  * Power off function, if any
  36  */
  37 void (*pm_power_off)(void);
  38 EXPORT_SYMBOL(pm_power_off);
  39
  40 static const struct desc_ptr no_idt = {};
  41
  42 /*
  43  * This is set if we need to go through the 'emergency' path.
  44  * When machine_emergency_restart() is called, we may be on
  45  * an inconsistent state and won't be able to do a clean cleanup
  46  */
  47 static int reboot_emergency;
  48
  49 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  50 bool port_cf9_safe = false;
  51
  52 /*
  53  * Reboot options and system auto-detection code provided by
  54  * Dell Inc. so their systems "just work". :-)
  55  */
  56
  57 /*
  58  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  59  * this quirk makes that automatic.
  60  */
  61 static int __init set_bios_reboot(const struct dmi_system_id *d)
  62 {
  63         if (reboot_type != BOOT_BIOS) {
  64                 reboot_type = BOOT_BIOS;
  65                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  66                         d->ident, "BIOS");
  67         }
  68         return 0;
  69 }
  70
  71 void __noreturn machine_real_restart(unsigned int type)
  72 {
  73         local_irq_disable();
  74
  75         /*
  76          * Write zero to CMOS register number 0x0f, which the BIOS POST
  77          * routine will recognize as telling it to do a proper reboot.  (Well
  78          * that's what this book in front of me says -- it may only apply to
  79          * the Phoenix BIOS though, it's not clear).  At the same time,
  80          * disable NMIs by setting the top bit in the CMOS address register,
  81          * as we're about to do peculiar things to the CPU.  I'm not sure if
  82          * `outb_p' is needed instead of just `outb'.  Use it to be on the
  83          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
  84          */
  85         spin_lock(&rtc_lock);
  86         CMOS_WRITE(0x00, 0x8f);
  87         spin_unlock(&rtc_lock);
  88
  89         /*
  90          * Switch back to the initial page table.
  91          */
  92 #ifdef CONFIG_X86_32
  93         load_cr3(initial_page_table);
  94 #else
  95         write_cr3(real_mode_header->trampoline_pgd);
  96 #endif
  97
  98         /* Jump to the identity-mapped low memory code */
  99 #ifdef CONFIG_X86_32
 100         asm volatile("jmpl *%0" : :
 101                      "rm" (real_mode_header->machine_real_restart_asm),
 102                      "a" (type));
 103 #else
 104         asm volatile("ljmpl *%0" : :
 105                      "m" (real_mode_header->machine_real_restart_asm),
 106                      "D" (type));
 107 #endif
 108         unreachable();
 109 }
 110 #ifdef CONFIG_APM_MODULE
 111 EXPORT_SYMBOL(machine_real_restart);
 112 #endif
 113
 114 /*
 115  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 116  */
 117 static int __init set_pci_reboot(const struct dmi_system_id *d)
 118 {
 119         if (reboot_type != BOOT_CF9_FORCE) {
 120                 reboot_type = BOOT_CF9_FORCE;
 121                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 122                         d->ident, "PCI");
 123         }
 124         return 0;
 125 }
 126
 127 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 128 {
 129         if (reboot_type != BOOT_KBD) {
 130                 reboot_type = BOOT_KBD;
 131                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 132                         d->ident, "KBD");
 133         }
 134         return 0;
 135 }
 136
 137 /*
 138  * This is a single dmi_table handling all reboot quirks.
 139  */
 140 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 141
 142         /* Acer */
 143         {       /* Handle reboot issue on Acer Aspire one */
 144                 .callback = set_kbd_reboot,
 145                 .ident = "Acer Aspire One A110",
 146                 .matches = {
 147                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 148                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 149                 },
 150         },
 151
 152         /* Apple */
 153         {       /* Handle problems with rebooting on Apple MacBook5 */
 154                 .callback = set_pci_reboot,
 155                 .ident = "Apple MacBook5",
 156                 .matches = {
 157                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 158                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 159                 },
 160         },
 161         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 162                 .callback = set_pci_reboot,
 163                 .ident = "Apple MacBookPro5",
 164                 .matches = {
 165                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 166                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 167                 },
 168         },
 169         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 170                 .callback = set_pci_reboot,
 171                 .ident = "Apple Macmini3,1",
 172                 .matches = {
 173                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 174                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 175                 },
 176         },
 177         {       /* Handle problems with rebooting on the iMac9,1. */
 178                 .callback = set_pci_reboot,
 179                 .ident = "Apple iMac9,1",
 180                 .matches = {
 181                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 182                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 183                 },
 184         },
 185         {       /* Handle problems with rebooting on the iMac10,1. */
 186                 .callback = set_pci_reboot,
 187                 .ident = "Apple iMac10,1",
 188                 .matches = {
 189                     DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 190                     DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
 191                 },
 192         },
 193
 194         /* ASRock */
 195         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
 196                 .callback = set_pci_reboot,
 197                 .ident = "ASRock Q1900DC-ITX",
 198                 .matches = {
 199                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
 200                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
 201                 },
 202         },
 203
 204         /* ASUS */
 205         {       /* Handle problems with rebooting on ASUS P4S800 */
 206                 .callback = set_bios_reboot,
 207                 .ident = "ASUS P4S800",
 208                 .matches = {
 209                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 210                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 211                 },
 212         },
 213
 214         /* Certec */
 215         {       /* Handle problems with rebooting on Certec BPC600 */
 216                 .callback = set_pci_reboot,
 217                 .ident = "Certec BPC600",
 218                 .matches = {
 219                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 220                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 221                 },
 222         },
 223
 224         /* Dell */
 225         {       /* Handle problems with rebooting on Dell DXP061 */
 226                 .callback = set_bios_reboot,
 227                 .ident = "Dell DXP061",
 228                 .matches = {
 229                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 230                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 231                 },
 232         },
 233         {       /* Handle problems with rebooting on Dell E520's */
 234                 .callback = set_bios_reboot,
 235                 .ident = "Dell E520",
 236                 .matches = {
 237                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 238                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 239                 },
 240         },
 241         {       /* Handle problems with rebooting on the Latitude E5410. */
 242                 .callback = set_pci_reboot,
 243                 .ident = "Dell Latitude E5410",
 244                 .matches = {
 245                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 246                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 247                 },
 248         },
 249         {       /* Handle problems with rebooting on the Latitude E5420. */
 250                 .callback = set_pci_reboot,
 251                 .ident = "Dell Latitude E5420",
 252                 .matches = {
 253                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 254                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 255                 },
 256         },
 257         {       /* Handle problems with rebooting on the Latitude E6320. */
 258                 .callback = set_pci_reboot,
 259                 .ident = "Dell Latitude E6320",
 260                 .matches = {
 261                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 262                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 263                 },
 264         },
 265         {       /* Handle problems with rebooting on the Latitude E6420. */
 266                 .callback = set_pci_reboot,
 267                 .ident = "Dell Latitude E6420",
 268                 .matches = {
 269                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 270                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 271                 },
 272         },
 273         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 274                 .callback = set_bios_reboot,
 275                 .ident = "Dell OptiPlex 330",
 276                 .matches = {
 277                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 278                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 279                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 280                 },
 281         },
 282         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 283                 .callback = set_bios_reboot,
 284                 .ident = "Dell OptiPlex 360",
 285                 .matches = {
 286                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 287                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 288                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 289                 },
 290         },
 291         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 292                 .callback = set_bios_reboot,
 293                 .ident = "Dell OptiPlex 745",
 294                 .matches = {
 295                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 296                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 297                 },
 298         },
 299         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 300                 .callback = set_bios_reboot,
 301                 .ident = "Dell OptiPlex 745",
 302                 .matches = {
 303                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 304                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 305                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 306                 },
 307         },
 308         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 309                 .callback = set_bios_reboot,
 310                 .ident = "Dell OptiPlex 745",
 311                 .matches = {
 312                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 313                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 314                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 315                 },
 316         },
 317         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 318                 .callback = set_bios_reboot,
 319                 .ident = "Dell OptiPlex 760",
 320                 .matches = {
 321                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 322                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 323                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 324                 },
 325         },
 326         {       /* Handle problems with rebooting on the OptiPlex 990. */
 327                 .callback = set_pci_reboot,
 328                 .ident = "Dell OptiPlex 990",
 329                 .matches = {
 330                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 331                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 332                 },
 333         },
 334         {       /* Handle problems with rebooting on Dell 300's */
 335                 .callback = set_bios_reboot,
 336                 .ident = "Dell PowerEdge 300",
 337                 .matches = {
 338                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 339                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 340                 },
 341         },
 342         {       /* Handle problems with rebooting on Dell 1300's */
 343                 .callback = set_bios_reboot,
 344                 .ident = "Dell PowerEdge 1300",
 345                 .matches = {
 346                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 347                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 348                 },
 349         },
 350         {       /* Handle problems with rebooting on Dell 2400's */
 351                 .callback = set_bios_reboot,
 352                 .ident = "Dell PowerEdge 2400",
 353                 .matches = {
 354                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 355                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 356                 },
 357         },
 358         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 359                 .callback = set_pci_reboot,
 360                 .ident = "Dell PowerEdge C6100",
 361                 .matches = {
 362                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 363                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 364                 },
 365         },
 366         {       /* Handle problems with rebooting on the Precision M6600. */
 367                 .callback = set_pci_reboot,
 368                 .ident = "Dell Precision M6600",
 369                 .matches = {
 370                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 371                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 372                 },
 373         },
 374         {       /* Handle problems with rebooting on Dell T5400's */
 375                 .callback = set_bios_reboot,
 376                 .ident = "Dell Precision T5400",
 377                 .matches = {
 378                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 379                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 380                 },
 381         },
 382         {       /* Handle problems with rebooting on Dell T7400's */
 383                 .callback = set_bios_reboot,
 384                 .ident = "Dell Precision T7400",
 385                 .matches = {
 386                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 387                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 388                 },
 389         },
 390         {       /* Handle problems with rebooting on Dell XPS710 */
 391                 .callback = set_bios_reboot,
 392                 .ident = "Dell XPS710",
 393                 .matches = {
 394                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 395                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 396                 },
 397         },
 398
 399         /* Hewlett-Packard */
 400         {       /* Handle problems with rebooting on HP laptops */
 401                 .callback = set_bios_reboot,
 402                 .ident = "HP Compaq Laptop",
 403                 .matches = {
 404                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 405                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 406                 },
 407         },
 408
 409         /* Sony */
 410         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 411                 .callback = set_bios_reboot,
 412                 .ident = "Sony VGN-Z540N",
 413                 .matches = {
 414                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 415                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 416                 },
 417         },
 418
 419         { }
 420 };
 421
 422 static int __init reboot_init(void)
 423 {
 424         int rv;
 425
 426         /*
 427          * Only do the DMI check if reboot_type hasn't been overridden
 428          * on the command line
 429          */
 430         if (!reboot_default)
 431                 return 0;
 432
 433         /*
 434          * The DMI quirks table takes precedence. If no quirks entry
 435          * matches and the ACPI Hardware Reduced bit is set, force EFI
 436          * reboot.
 437          */
 438         rv = dmi_check_system(reboot_dmi_table);
 439
 440         if (!rv && efi_reboot_required())
 441                 reboot_type = BOOT_EFI;
 442
 443         return 0;
 444 }
 445 core_initcall(reboot_init);
 446
 447 static inline void kb_wait(void)
 448 {
 449         int i;
 450
 451         for (i = 0; i < 0x10000; i++) {
 452                 if ((inb(0x64) & 0x02) == 0)
 453                         break;
 454                 udelay(2);
 455         }
 456 }
 457
 458 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 459 {
 460         cpu_emergency_vmxoff();
 461 }
 462
 463 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 464 static void emergency_vmx_disable_all(void)
 465 {
 466         /* Just make sure we won't change CPUs while doing this */
 467         local_irq_disable();
 468
 469         /*
 470          * We need to disable VMX on all CPUs before rebooting, otherwise
 471          * we risk hanging up the machine, because the CPU ignore INIT
 472          * signals when VMX is enabled.
 473          *
 474          * We can't take any locks and we may be on an inconsistent
 475          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 476          * VMX and halt.
 477          *
 478          * For safety, we will avoid running the nmi_shootdown_cpus()
 479          * stuff unnecessarily, but we don't have a way to check
 480          * if other CPUs have VMX enabled. So we will call it only if the
 481          * CPU we are running on has VMX enabled.
 482          *
 483          * We will miss cases where VMX is not enabled on all CPUs. This
 484          * shouldn't do much harm because KVM always enable VMX on all
 485          * CPUs anyway. But we can miss it on the small window where KVM
 486          * is still enabling VMX.
 487          */
 488         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 489                 /* Disable VMX on this CPU. */
 490                 cpu_vmxoff();
 491
 492                 /* Halt and disable VMX on the other CPUs */
 493                 nmi_shootdown_cpus(vmxoff_nmi);
 494
 495         }
 496 }
 497
 498
 499 void __attribute__((weak)) mach_reboot_fixups(void)
 500 {
 501 }
 502
 503 /*
 504  * To the best of our knowledge Windows compatible x86 hardware expects
 505  * the following on reboot:
 506  *
 507  * 1) If the FADT has the ACPI reboot register flag set, try it
 508  * 2) If still alive, write to the keyboard controller
 509  * 3) If still alive, write to the ACPI reboot register again
 510  * 4) If still alive, write to the keyboard controller again
 511  * 5) If still alive, call the EFI runtime service to reboot
 512  * 6) If no EFI runtime service, call the BIOS to do a reboot
 513  *
 514  * We default to following the same pattern. We also have
 515  * two other reboot methods: 'triple fault' and 'PCI', which
 516  * can be triggered via the reboot= kernel boot option or
 517  * via quirks.
 518  *
 519  * This means that this function can never return, it can misbehave
 520  * by not rebooting properly and hanging.
 521  */
 522 static void native_machine_emergency_restart(void)
 523 {
 524         int i;
 525         int attempt = 0;
 526         int orig_reboot_type = reboot_type;
 527         unsigned short mode;
 528
 529         if (reboot_emergency)
 530                 emergency_vmx_disable_all();
 531
 532         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 533
 534         /* Tell the BIOS if we want cold or warm reboot */
 535         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 536         *((unsigned short *)__va(0x472)) = mode;
 537
 538         /*
 539          * If an EFI capsule has been registered with the firmware then
 540          * override the reboot= parameter.
 541          */
 542         if (efi_capsule_pending(NULL)) {
 543                 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
 544                 reboot_type = BOOT_EFI;
 545         }
 546
 547         for (;;) {
 548                 /* Could also try the reset bit in the Hammer NB */
 549                 switch (reboot_type) {
 550                 case BOOT_ACPI:
 551                         acpi_reboot();
 552                         reboot_type = BOOT_KBD;
 553                         break;
 554
 555                 case BOOT_KBD:
 556                         mach_reboot_fixups(); /* For board specific fixups */
 557
 558                         for (i = 0; i < 10; i++) {
 559                                 kb_wait();
 560                                 udelay(50);
 561                                 outb(0xfe, 0x64); /* Pulse reset low */
 562                                 udelay(50);
 563                         }
 564                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 565                                 attempt = 1;
 566                                 reboot_type = BOOT_ACPI;
 567                         } else {
 568                                 reboot_type = BOOT_EFI;
 569                         }
 570                         break;
 571
 572                 case BOOT_EFI:
 573                         efi_reboot(reboot_mode, NULL);
 574                         reboot_type = BOOT_BIOS;
 575                         break;
 576
 577                 case BOOT_BIOS:
 578                         machine_real_restart(MRR_BIOS);
 579
 580                         /* We're probably dead after this, but... */
 581                         reboot_type = BOOT_CF9_SAFE;
 582                         break;
 583
 584                 case BOOT_CF9_FORCE:
 585                         port_cf9_safe = true;
 586                         /* Fall through */
 587
 588                 case BOOT_CF9_SAFE:
 589                         if (port_cf9_safe) {
 590                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 591                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 592                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 593                                 udelay(50);
 594                                 /* Actually do the reset */
 595                                 outb(cf9|reboot_code, 0xcf9);
 596                                 udelay(50);
 597                         }
 598                         reboot_type = BOOT_TRIPLE;
 599                         break;
 600
 601                 case BOOT_TRIPLE:
 602                         load_idt(&no_idt);
 603                         __asm__ __volatile__("int3");
 604
 605                         /* We're probably dead after this, but... */
 606                         reboot_type = BOOT_KBD;
 607                         break;
 608                 }
 609         }
 610 }
 611
 612 void native_machine_shutdown(void)
 613 {
 614         /* Stop the cpus and apics */
 615 #ifdef CONFIG_X86_IO_APIC
 616         /*
 617          * Disabling IO APIC before local APIC is a workaround for
 618          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 619          * Specification Update". In this situation, interrupts that target
 620          * a Logical Processor whose Local APIC is either in the process of
 621          * being hardware disabled or software disabled are neither delivered
 622          * nor discarded. When this erratum occurs, the processor may hang.
 623          *
 624          * Even without the erratum, it still makes sense to quiet IO APIC
 625          * before disabling Local APIC.
 626          */
 627         disable_IO_APIC();
 628 #endif
 629
 630 #ifdef CONFIG_SMP
 631         /*
 632          * Stop all of the others. Also disable the local irq to
 633          * not receive the per-cpu timer interrupt which may trigger
 634          * scheduler's load balance.
 635          */
 636         local_irq_disable();
 637         stop_other_cpus();
 638 #endif
 639
 640         lapic_shutdown();
 641
 642 #ifdef CONFIG_HPET_TIMER
 643         hpet_disable();
 644 #endif
 645
 646 #ifdef CONFIG_X86_64
 647         x86_platform.iommu_shutdown();
 648 #endif
 649 }
 650
 651 static void __machine_emergency_restart(int emergency)
 652 {
 653         reboot_emergency = emergency;
 654         machine_ops.emergency_restart();
 655 }
 656
 657 static void native_machine_restart(char *__unused)
 658 {
 659         pr_notice("machine restart\n");
 660
 661         if (!reboot_force)
 662                 machine_shutdown();
 663         __machine_emergency_restart(0);
 664 }
 665
 666 static void native_machine_halt(void)
 667 {
 668         /* Stop other cpus and apics */
 669         machine_shutdown();
 670
 671         tboot_shutdown(TB_SHUTDOWN_HALT);
 672
 673         stop_this_cpu(NULL);
 674 }
 675
 676 static void native_machine_power_off(void)
 677 {
 678         if (pm_power_off) {
 679                 if (!reboot_force)
 680                         machine_shutdown();
 681                 pm_power_off();
 682         }
 683         /* A fallback in case there is no PM info available */
 684         tboot_shutdown(TB_SHUTDOWN_HALT);
 685 }
 686
 687 struct machine_ops machine_ops = {
 688         .power_off = native_machine_power_off,
 689         .shutdown = native_machine_shutdown,
 690         .emergency_restart = native_machine_emergency_restart,
 691         .restart = native_machine_restart,
 692         .halt = native_machine_halt,
 693 #ifdef CONFIG_KEXEC_CORE
 694         .crash_shutdown = native_machine_crash_shutdown,
 695 #endif
 696 };
 697
 698 void machine_power_off(void)
 699 {
 700         machine_ops.power_off();
 701 }
 702
 703 void machine_shutdown(void)
 704 {
 705         machine_ops.shutdown();
 706 }
 707
 708 void machine_emergency_restart(void)
 709 {
 710         __machine_emergency_restart(1);
 711 }
 712
 713 void machine_restart(char *cmd)
 714 {
 715         machine_ops.restart(cmd);
 716 }
 717
 718 void machine_halt(void)
 719 {
 720         machine_ops.halt();
 721 }
 722
 723 #ifdef CONFIG_KEXEC_CORE
 724 void machine_crash_shutdown(struct pt_regs *regs)
 725 {
 726         machine_ops.crash_shutdown(regs);
 727 }
 728 #endif
 729
 730
 731 #if defined(CONFIG_SMP)
 732
 733 /* This keeps a track of which one is crashing cpu. */
 734 static int crashing_cpu;
 735 static nmi_shootdown_cb shootdown_callback;
 736
 737 static atomic_t waiting_for_crash_ipi;
 738 static int crash_ipi_issued;
 739
 740 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 741 {
 742         int cpu;
 743
 744         cpu = raw_smp_processor_id();
 745
 746         /*
 747          * Don't do anything if this handler is invoked on crashing cpu.
 748          * Otherwise, system will completely hang. Crashing cpu can get
 749          * an NMI if system was initially booted with nmi_watchdog parameter.
 750          */
 751         if (cpu == crashing_cpu)
 752                 return NMI_HANDLED;
 753         local_irq_disable();
 754
 755         shootdown_callback(cpu, regs);
 756
 757         atomic_dec(&waiting_for_crash_ipi);
 758         /* Assume hlt works */
 759         halt();
 760         for (;;)
 761                 cpu_relax();
 762
 763         return NMI_HANDLED;
 764 }
 765
 766 static void smp_send_nmi_allbutself(void)
 767 {
 768         apic->send_IPI_allbutself(NMI_VECTOR);
 769 }
 770
 771 /*
 772  * Halt all other CPUs, calling the specified function on each of them
 773  *
 774  * This function can be used to halt all other CPUs on crash
 775  * or emergency reboot time. The function passed as parameter
 776  * will be called inside a NMI handler on all CPUs.
 777  */
 778 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 779 {
 780         unsigned long msecs;
 781         local_irq_disable();
 782
 783         /* Make a note of crashing cpu. Will be used in NMI callback. */
 784         crashing_cpu = safe_smp_processor_id();
 785
 786         shootdown_callback = callback;
 787
 788         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 789         /* Would it be better to replace the trap vector here? */
 790         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 791                                  NMI_FLAG_FIRST, "crash"))
 792                 return;         /* Return what? */
 793         /*
 794          * Ensure the new callback function is set before sending
 795          * out the NMI
 796          */
 797         wmb();
 798
 799         smp_send_nmi_allbutself();
 800
 801         /* Kick CPUs looping in NMI context. */
 802         WRITE_ONCE(crash_ipi_issued, 1);
 803
 804         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 805         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 806                 mdelay(1);
 807                 msecs--;
 808         }
 809
 810         /* Leave the nmi callback set */
 811 }
 812
 813 /*
 814  * Check if the crash dumping IPI got issued and if so, call its callback
 815  * directly. This function is used when we have already been in NMI handler.
 816  * It doesn't return.
 817  */
 818 void run_crash_ipi_callback(struct pt_regs *regs)
 819 {
 820         if (crash_ipi_issued)
 821                 crash_nmi_callback(0, regs);
 822 }
 823
 824 /* Override the weak function in kernel/panic.c */
 825 void nmi_panic_self_stop(struct pt_regs *regs)
 826 {
 827         while (1) {
 828                 /* If no CPU is preparing crash dump, we simply loop here. */
 829                 run_crash_ipi_callback(regs);
 830                 cpu_relax();
 831         }
 832 }
 833
 834 #else /* !CONFIG_SMP */
 835 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 836 {
 837         /* No other CPUs to shoot down */
 838 }
 839
 840 void run_crash_ipi_callback(struct pt_regs *regs)
 841 {
 842 }
 843 #endif