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
 186         /* ASRock */
 187         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
 188                 .callback = set_pci_reboot,
 189                 .ident = "ASRock Q1900DC-ITX",
 190                 .matches = {
 191                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
 192                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
 193                 },
 194         },
 195
 196         /* ASUS */
 197         {       /* Handle problems with rebooting on ASUS P4S800 */
 198                 .callback = set_bios_reboot,
 199                 .ident = "ASUS P4S800",
 200                 .matches = {
 201                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 202                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 203                 },
 204         },
 205
 206         /* Certec */
 207         {       /* Handle problems with rebooting on Certec BPC600 */
 208                 .callback = set_pci_reboot,
 209                 .ident = "Certec BPC600",
 210                 .matches = {
 211                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 212                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 213                 },
 214         },
 215
 216         /* Dell */
 217         {       /* Handle problems with rebooting on Dell DXP061 */
 218                 .callback = set_bios_reboot,
 219                 .ident = "Dell DXP061",
 220                 .matches = {
 221                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 222                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 223                 },
 224         },
 225         {       /* Handle problems with rebooting on Dell E520's */
 226                 .callback = set_bios_reboot,
 227                 .ident = "Dell E520",
 228                 .matches = {
 229                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 230                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 231                 },
 232         },
 233         {       /* Handle problems with rebooting on the Latitude E5410. */
 234                 .callback = set_pci_reboot,
 235                 .ident = "Dell Latitude E5410",
 236                 .matches = {
 237                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 238                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 239                 },
 240         },
 241         {       /* Handle problems with rebooting on the Latitude E5420. */
 242                 .callback = set_pci_reboot,
 243                 .ident = "Dell Latitude E5420",
 244                 .matches = {
 245                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 246                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 247                 },
 248         },
 249         {       /* Handle problems with rebooting on the Latitude E6320. */
 250                 .callback = set_pci_reboot,
 251                 .ident = "Dell Latitude E6320",
 252                 .matches = {
 253                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 254                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 255                 },
 256         },
 257         {       /* Handle problems with rebooting on the Latitude E6420. */
 258                 .callback = set_pci_reboot,
 259                 .ident = "Dell Latitude E6420",
 260                 .matches = {
 261                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 262                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 263                 },
 264         },
 265         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 266                 .callback = set_bios_reboot,
 267                 .ident = "Dell OptiPlex 330",
 268                 .matches = {
 269                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 270                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 271                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 272                 },
 273         },
 274         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 275                 .callback = set_bios_reboot,
 276                 .ident = "Dell OptiPlex 360",
 277                 .matches = {
 278                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 279                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 280                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 281                 },
 282         },
 283         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 284                 .callback = set_bios_reboot,
 285                 .ident = "Dell OptiPlex 745",
 286                 .matches = {
 287                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 288                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 289                 },
 290         },
 291         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 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                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 298                 },
 299         },
 300         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 301                 .callback = set_bios_reboot,
 302                 .ident = "Dell OptiPlex 745",
 303                 .matches = {
 304                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 305                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 306                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 307                 },
 308         },
 309         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 310                 .callback = set_bios_reboot,
 311                 .ident = "Dell OptiPlex 760",
 312                 .matches = {
 313                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 314                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 315                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 316                 },
 317         },
 318         {       /* Handle problems with rebooting on the OptiPlex 990. */
 319                 .callback = set_pci_reboot,
 320                 .ident = "Dell OptiPlex 990",
 321                 .matches = {
 322                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 323                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 324                 },
 325         },
 326         {       /* Handle problems with rebooting on Dell 300's */
 327                 .callback = set_bios_reboot,
 328                 .ident = "Dell PowerEdge 300",
 329                 .matches = {
 330                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 331                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 332                 },
 333         },
 334         {       /* Handle problems with rebooting on Dell 1300's */
 335                 .callback = set_bios_reboot,
 336                 .ident = "Dell PowerEdge 1300",
 337                 .matches = {
 338                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 339                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 340                 },
 341         },
 342         {       /* Handle problems with rebooting on Dell 2400's */
 343                 .callback = set_bios_reboot,
 344                 .ident = "Dell PowerEdge 2400",
 345                 .matches = {
 346                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 347                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 348                 },
 349         },
 350         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 351                 .callback = set_pci_reboot,
 352                 .ident = "Dell PowerEdge C6100",
 353                 .matches = {
 354                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 355                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 356                 },
 357         },
 358         {       /* Handle problems with rebooting on the Precision M6600. */
 359                 .callback = set_pci_reboot,
 360                 .ident = "Dell Precision M6600",
 361                 .matches = {
 362                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 363                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 364                 },
 365         },
 366         {       /* Handle problems with rebooting on Dell T5400's */
 367                 .callback = set_bios_reboot,
 368                 .ident = "Dell Precision T5400",
 369                 .matches = {
 370                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 371                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 372                 },
 373         },
 374         {       /* Handle problems with rebooting on Dell T7400's */
 375                 .callback = set_bios_reboot,
 376                 .ident = "Dell Precision T7400",
 377                 .matches = {
 378                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 379                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 380                 },
 381         },
 382         {       /* Handle problems with rebooting on Dell XPS710 */
 383                 .callback = set_bios_reboot,
 384                 .ident = "Dell XPS710",
 385                 .matches = {
 386                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 387                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 388                 },
 389         },
 390
 391         /* Hewlett-Packard */
 392         {       /* Handle problems with rebooting on HP laptops */
 393                 .callback = set_bios_reboot,
 394                 .ident = "HP Compaq Laptop",
 395                 .matches = {
 396                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 397                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 398                 },
 399         },
 400
 401         /* Sony */
 402         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 403                 .callback = set_bios_reboot,
 404                 .ident = "Sony VGN-Z540N",
 405                 .matches = {
 406                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 407                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 408                 },
 409         },
 410
 411         { }
 412 };
 413
 414 static int __init reboot_init(void)
 415 {
 416         int rv;
 417
 418         /*
 419          * Only do the DMI check if reboot_type hasn't been overridden
 420          * on the command line
 421          */
 422         if (!reboot_default)
 423                 return 0;
 424
 425         /*
 426          * The DMI quirks table takes precedence. If no quirks entry
 427          * matches and the ACPI Hardware Reduced bit is set, force EFI
 428          * reboot.
 429          */
 430         rv = dmi_check_system(reboot_dmi_table);
 431
 432         if (!rv && efi_reboot_required())
 433                 reboot_type = BOOT_EFI;
 434
 435         return 0;
 436 }
 437 core_initcall(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 pt_regs *regs)
 451 {
 452         cpu_emergency_vmxoff();
 453 }
 454
 455 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 456 static void emergency_vmx_disable_all(void)
 457 {
 458         /* Just make sure we won't change CPUs while doing this */
 459         local_irq_disable();
 460
 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                 cpu_vmxoff();
 483
 484                 /* Halt and disable VMX on the other CPUs */
 485                 nmi_shootdown_cpus(vmxoff_nmi);
 486
 487         }
 488 }
 489
 490
 491 void __attribute__((weak)) mach_reboot_fixups(void)
 492 {
 493 }
 494
 495 /*
 496  * To the best of our knowledge Windows compatible x86 hardware expects
 497  * the following on reboot:
 498  *
 499  * 1) If the FADT has the ACPI reboot register flag set, try it
 500  * 2) If still alive, write to the keyboard controller
 501  * 3) If still alive, write to the ACPI reboot register again
 502  * 4) If still alive, write to the keyboard controller again
 503  * 5) If still alive, call the EFI runtime service to reboot
 504  * 6) If no EFI runtime service, call the BIOS to do a reboot
 505  *
 506  * We default to following the same pattern. We also have
 507  * two other reboot methods: 'triple fault' and 'PCI', which
 508  * can be triggered via the reboot= kernel boot option or
 509  * via quirks.
 510  *
 511  * This means that this function can never return, it can misbehave
 512  * by not rebooting properly and hanging.
 513  */
 514 static void native_machine_emergency_restart(void)
 515 {
 516         int i;
 517         int attempt = 0;
 518         int orig_reboot_type = reboot_type;
 519         unsigned short mode;
 520
 521         if (reboot_emergency)
 522                 emergency_vmx_disable_all();
 523
 524         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 525
 526         /* Tell the BIOS if we want cold or warm reboot */
 527         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 528         *((unsigned short *)__va(0x472)) = mode;
 529
 530         for (;;) {
 531                 /* Could also try the reset bit in the Hammer NB */
 532                 switch (reboot_type) {
 533                 case BOOT_ACPI:
 534                         acpi_reboot();
 535                         reboot_type = BOOT_KBD;
 536                         break;
 537
 538                 case BOOT_KBD:
 539                         mach_reboot_fixups(); /* For board specific fixups */
 540
 541                         for (i = 0; i < 10; i++) {
 542                                 kb_wait();
 543                                 udelay(50);
 544                                 outb(0xfe, 0x64); /* Pulse reset low */
 545                                 udelay(50);
 546                         }
 547                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 548                                 attempt = 1;
 549                                 reboot_type = BOOT_ACPI;
 550                         } else {
 551                                 reboot_type = BOOT_EFI;
 552                         }
 553                         break;
 554
 555                 case BOOT_EFI:
 556                         efi_reboot(reboot_mode, NULL);
 557                         reboot_type = BOOT_BIOS;
 558                         break;
 559
 560                 case BOOT_BIOS:
 561                         machine_real_restart(MRR_BIOS);
 562
 563                         /* We're probably dead after this, but... */
 564                         reboot_type = BOOT_CF9_SAFE;
 565                         break;
 566
 567                 case BOOT_CF9_FORCE:
 568                         port_cf9_safe = true;
 569                         /* Fall through */
 570
 571                 case BOOT_CF9_SAFE:
 572                         if (port_cf9_safe) {
 573                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 574                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 575                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 576                                 udelay(50);
 577                                 /* Actually do the reset */
 578                                 outb(cf9|reboot_code, 0xcf9);
 579                                 udelay(50);
 580                         }
 581                         reboot_type = BOOT_TRIPLE;
 582                         break;
 583
 584                 case BOOT_TRIPLE:
 585                         load_idt(&no_idt);
 586                         __asm__ __volatile__("int3");
 587
 588                         /* We're probably dead after this, but... */
 589                         reboot_type = BOOT_KBD;
 590                         break;
 591                 }
 592         }
 593 }
 594
 595 void native_machine_shutdown(void)
 596 {
 597         /* Stop the cpus and apics */
 598 #ifdef CONFIG_X86_IO_APIC
 599         /*
 600          * Disabling IO APIC before local APIC is a workaround for
 601          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 602          * Specification Update". In this situation, interrupts that target
 603          * a Logical Processor whose Local APIC is either in the process of
 604          * being hardware disabled or software disabled are neither delivered
 605          * nor discarded. When this erratum occurs, the processor may hang.
 606          *
 607          * Even without the erratum, it still makes sense to quiet IO APIC
 608          * before disabling Local APIC.
 609          */
 610         disable_IO_APIC();
 611 #endif
 612
 613 #ifdef CONFIG_SMP
 614         /*
 615          * Stop all of the others. Also disable the local irq to
 616          * not receive the per-cpu timer interrupt which may trigger
 617          * scheduler's load balance.
 618          */
 619         local_irq_disable();
 620         stop_other_cpus();
 621 #endif
 622
 623         lapic_shutdown();
 624
 625 #ifdef CONFIG_HPET_TIMER
 626         hpet_disable();
 627 #endif
 628
 629 #ifdef CONFIG_X86_64
 630         x86_platform.iommu_shutdown();
 631 #endif
 632 }
 633
 634 static void __machine_emergency_restart(int emergency)
 635 {
 636         reboot_emergency = emergency;
 637         machine_ops.emergency_restart();
 638 }
 639
 640 static void native_machine_restart(char *__unused)
 641 {
 642         pr_notice("machine restart\n");
 643
 644         if (!reboot_force)
 645                 machine_shutdown();
 646         __machine_emergency_restart(0);
 647 }
 648
 649 static void native_machine_halt(void)
 650 {
 651         /* Stop other cpus and apics */
 652         machine_shutdown();
 653
 654         tboot_shutdown(TB_SHUTDOWN_HALT);
 655
 656         stop_this_cpu(NULL);
 657 }
 658
 659 static void native_machine_power_off(void)
 660 {
 661         if (pm_power_off) {
 662                 if (!reboot_force)
 663                         machine_shutdown();
 664                 pm_power_off();
 665         }
 666         /* A fallback in case there is no PM info available */
 667         tboot_shutdown(TB_SHUTDOWN_HALT);
 668 }
 669
 670 struct machine_ops machine_ops = {
 671         .power_off = native_machine_power_off,
 672         .shutdown = native_machine_shutdown,
 673         .emergency_restart = native_machine_emergency_restart,
 674         .restart = native_machine_restart,
 675         .halt = native_machine_halt,
 676 #ifdef CONFIG_KEXEC
 677         .crash_shutdown = native_machine_crash_shutdown,
 678 #endif
 679 };
 680
 681 void machine_power_off(void)
 682 {
 683         machine_ops.power_off();
 684 }
 685
 686 void machine_shutdown(void)
 687 {
 688         machine_ops.shutdown();
 689 }
 690
 691 void machine_emergency_restart(void)
 692 {
 693         __machine_emergency_restart(1);
 694 }
 695
 696 void machine_restart(char *cmd)
 697 {
 698         machine_ops.restart(cmd);
 699 }
 700
 701 void machine_halt(void)
 702 {
 703         machine_ops.halt();
 704 }
 705
 706 #ifdef CONFIG_KEXEC
 707 void machine_crash_shutdown(struct pt_regs *regs)
 708 {
 709         machine_ops.crash_shutdown(regs);
 710 }
 711 #endif
 712
 713
 714 #if defined(CONFIG_SMP)
 715
 716 /* This keeps a track of which one is crashing cpu. */
 717 static int crashing_cpu;
 718 static nmi_shootdown_cb shootdown_callback;
 719
 720 static atomic_t waiting_for_crash_ipi;
 721
 722 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 723 {
 724         int cpu;
 725
 726         cpu = raw_smp_processor_id();
 727
 728         /*
 729          * Don't do anything if this handler is invoked on crashing cpu.
 730          * Otherwise, system will completely hang. Crashing cpu can get
 731          * an NMI if system was initially booted with nmi_watchdog parameter.
 732          */
 733         if (cpu == crashing_cpu)
 734                 return NMI_HANDLED;
 735         local_irq_disable();
 736
 737         shootdown_callback(cpu, regs);
 738
 739         atomic_dec(&waiting_for_crash_ipi);
 740         /* Assume hlt works */
 741         halt();
 742         for (;;)
 743                 cpu_relax();
 744
 745         return NMI_HANDLED;
 746 }
 747
 748 static void smp_send_nmi_allbutself(void)
 749 {
 750         apic->send_IPI_allbutself(NMI_VECTOR);
 751 }
 752
 753 /*
 754  * Halt all other CPUs, calling the specified function on each of them
 755  *
 756  * This function can be used to halt all other CPUs on crash
 757  * or emergency reboot time. The function passed as parameter
 758  * will be called inside a NMI handler on all CPUs.
 759  */
 760 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 761 {
 762         unsigned long msecs;
 763         local_irq_disable();
 764
 765         /* Make a note of crashing cpu. Will be used in NMI callback. */
 766         crashing_cpu = safe_smp_processor_id();
 767
 768         shootdown_callback = callback;
 769
 770         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 771         /* Would it be better to replace the trap vector here? */
 772         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 773                                  NMI_FLAG_FIRST, "crash"))
 774                 return;         /* Return what? */
 775         /*
 776          * Ensure the new callback function is set before sending
 777          * out the NMI
 778          */
 779         wmb();
 780
 781         smp_send_nmi_allbutself();
 782
 783         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 784         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 785                 mdelay(1);
 786                 msecs--;
 787         }
 788
 789         /* Leave the nmi callback set */
 790 }
 791 #else /* !CONFIG_SMP */
 792 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 793 {
 794         /* No other CPUs to shoot down */
 795 }
 796 #endif