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 static int reboot_mode;
  40 enum reboot_type reboot_type = BOOT_ACPI;
  41 int reboot_force;
  42
  43 /*
  44  * This variable is used privately to keep track of whether or not
  45  * reboot_type is still set to its default value (i.e., reboot= hasn't
  46  * been set on the command line).  This is needed so that we can
  47  * suppress DMI scanning for reboot quirks.  Without it, it's
  48  * impossible to override a faulty reboot quirk without recompiling.
  49  */
  50 static int reboot_default = 1;
  51
  52 #ifdef CONFIG_SMP
  53 static int reboot_cpu = -1;
  54 #endif
  55
  56 /*
  57  * This is set if we need to go through the 'emergency' path.
  58  * When machine_emergency_restart() is called, we may be on
  59  * an inconsistent state and won't be able to do a clean cleanup
  60  */
  61 static int reboot_emergency;
  62
  63 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  64 bool port_cf9_safe = false;
  65
  66 /*
  67  * reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
  68  * warm   Don't set the cold reboot flag
  69  * cold   Set the cold reboot flag
  70  * bios   Reboot by jumping through the BIOS
  71  * smp    Reboot by executing reset on BSP or other CPU
  72  * triple Force a triple fault (init)
  73  * kbd    Use the keyboard controller. cold reset (default)
  74  * acpi   Use the RESET_REG in the FADT
  75  * efi    Use efi reset_system runtime service
  76  * pci    Use the so-called "PCI reset register", CF9
  77  * force  Avoid anything that could hang.
  78  */
  79 static int __init reboot_setup(char *str)
  80 {
  81         for (;;) {
  82                 /*
  83                  * Having anything passed on the command line via
  84                  * reboot= will cause us to disable DMI checking
  85                  * below.
  86                  */
  87                 reboot_default = 0;
  88
  89                 switch (*str) {
  90                 case 'w':
  91                         reboot_mode = 0x1234;
  92                         break;
  93
  94                 case 'c':
  95                         reboot_mode = 0;
  96                         break;
  97
  98 #ifdef CONFIG_SMP
  99                 case 's':
 100                         if (isdigit(*(str+1))) {
 101                                 reboot_cpu = (int) (*(str+1) - '0');
 102                                 if (isdigit(*(str+2)))
 103                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
 104                         }
 105                         /*
 106                          * We will leave sorting out the final value
 107                          * when we are ready to reboot, since we might not
 108                          * have detected BSP APIC ID or smp_num_cpu
 109                          */
 110                         break;
 111 #endif /* CONFIG_SMP */
 112
 113                 case 'b':
 114                 case 'a':
 115                 case 'k':
 116                 case 't':
 117                 case 'e':
 118                 case 'p':
 119                         reboot_type = *str;
 120                         break;
 121
 122                 case 'f':
 123                         reboot_force = 1;
 124                         break;
 125                 }
 126
 127                 str = strchr(str, ',');
 128                 if (str)
 129                         str++;
 130                 else
 131                         break;
 132         }
 133         return 1;
 134 }
 135
 136 __setup("reboot=", reboot_setup);
 137
 138
 139 /*
 140  * Reboot options and system auto-detection code provided by
 141  * Dell Inc. so their systems "just work". :-)
 142  */
 143
 144 /*
 145  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
 146  * this quirk makes that automatic.
 147  */
 148 static int __init set_bios_reboot(const struct dmi_system_id *d)
 149 {
 150         if (reboot_type != BOOT_BIOS) {
 151                 reboot_type = BOOT_BIOS;
 152                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 153                         "BIOS", d->ident);
 154         }
 155         return 0;
 156 }
 157
 158 void __noreturn machine_real_restart(unsigned int type)
 159 {
 160         local_irq_disable();
 161
 162         /*
 163          * Write zero to CMOS register number 0x0f, which the BIOS POST
 164          * routine will recognize as telling it to do a proper reboot.  (Well
 165          * that's what this book in front of me says -- it may only apply to
 166          * the Phoenix BIOS though, it's not clear).  At the same time,
 167          * disable NMIs by setting the top bit in the CMOS address register,
 168          * as we're about to do peculiar things to the CPU.  I'm not sure if
 169          * `outb_p' is needed instead of just `outb'.  Use it to be on the
 170          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 171          */
 172         spin_lock(&rtc_lock);
 173         CMOS_WRITE(0x00, 0x8f);
 174         spin_unlock(&rtc_lock);
 175
 176         /*
 177          * Switch back to the initial page table.
 178          */
 179 #ifdef CONFIG_X86_32
 180         load_cr3(initial_page_table);
 181 #else
 182         write_cr3(real_mode_header->trampoline_pgd);
 183 #endif
 184
 185         /* Jump to the identity-mapped low memory code */
 186 #ifdef CONFIG_X86_32
 187         asm volatile("jmpl *%0" : :
 188                      "rm" (real_mode_header->machine_real_restart_asm),
 189                      "a" (type));
 190 #else
 191         asm volatile("ljmpl *%0" : :
 192                      "m" (real_mode_header->machine_real_restart_asm),
 193                      "D" (type));
 194 #endif
 195         unreachable();
 196 }
 197 #ifdef CONFIG_APM_MODULE
 198 EXPORT_SYMBOL(machine_real_restart);
 199 #endif
 200
 201 /*
 202  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 203  */
 204 static int __init set_pci_reboot(const struct dmi_system_id *d)
 205 {
 206         if (reboot_type != BOOT_CF9) {
 207                 reboot_type = BOOT_CF9;
 208                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 209                         "PCI", d->ident);
 210         }
 211         return 0;
 212 }
 213
 214 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 215 {
 216         if (reboot_type != BOOT_KBD) {
 217                 reboot_type = BOOT_KBD;
 218                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 219                         "KBD", d->ident);
 220         }
 221         return 0;
 222 }
 223
 224 /*
 225  * This is a single dmi_table handling all reboot quirks.
 226  */
 227 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 228         {       /* Handle problems with rebooting on Dell E520's */
 229                 .callback = set_bios_reboot,
 230                 .ident = "Dell E520",
 231                 .matches = {
 232                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 233                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 234                 },
 235         },
 236         {       /* Handle problems with rebooting on Dell 1300's */
 237                 .callback = set_bios_reboot,
 238                 .ident = "Dell PowerEdge 1300",
 239                 .matches = {
 240                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 241                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 242                 },
 243         },
 244         {       /* Handle problems with rebooting on Dell 300's */
 245                 .callback = set_bios_reboot,
 246                 .ident = "Dell PowerEdge 300",
 247                 .matches = {
 248                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 249                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 250                 },
 251         },
 252         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 253                 .callback = set_bios_reboot,
 254                 .ident = "Dell OptiPlex 745",
 255                 .matches = {
 256                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 257                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 258                 },
 259         },
 260         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 261                 .callback = set_bios_reboot,
 262                 .ident = "Dell OptiPlex 745",
 263                 .matches = {
 264                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 265                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 266                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 267                 },
 268         },
 269         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 270                 .callback = set_bios_reboot,
 271                 .ident = "Dell OptiPlex 745",
 272                 .matches = {
 273                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 274                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 275                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 276                 },
 277         },
 278         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 279                 .callback = set_bios_reboot,
 280                 .ident = "Dell OptiPlex 330",
 281                 .matches = {
 282                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 283                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 284                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 285                 },
 286         },
 287         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 288                 .callback = set_bios_reboot,
 289                 .ident = "Dell OptiPlex 360",
 290                 .matches = {
 291                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 292                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 293                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 294                 },
 295         },
 296         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 297                 .callback = set_bios_reboot,
 298                 .ident = "Dell OptiPlex 760",
 299                 .matches = {
 300                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 301                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 302                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 303                 },
 304         },
 305         {       /* Handle problems with rebooting on Dell 2400's */
 306                 .callback = set_bios_reboot,
 307                 .ident = "Dell PowerEdge 2400",
 308                 .matches = {
 309                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 310                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 311                 },
 312         },
 313         {       /* Handle problems with rebooting on Dell T5400's */
 314                 .callback = set_bios_reboot,
 315                 .ident = "Dell Precision T5400",
 316                 .matches = {
 317                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 318                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 319                 },
 320         },
 321         {       /* Handle problems with rebooting on Dell T7400's */
 322                 .callback = set_bios_reboot,
 323                 .ident = "Dell Precision T7400",
 324                 .matches = {
 325                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 326                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 327                 },
 328         },
 329         {       /* Handle problems with rebooting on HP laptops */
 330                 .callback = set_bios_reboot,
 331                 .ident = "HP Compaq Laptop",
 332                 .matches = {
 333                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 334                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 335                 },
 336         },
 337         {       /* Handle problems with rebooting on Dell XPS710 */
 338                 .callback = set_bios_reboot,
 339                 .ident = "Dell XPS710",
 340                 .matches = {
 341                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 342                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 343                 },
 344         },
 345         {       /* Handle problems with rebooting on Dell DXP061 */
 346                 .callback = set_bios_reboot,
 347                 .ident = "Dell DXP061",
 348                 .matches = {
 349                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 350                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 351                 },
 352         },
 353         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 354                 .callback = set_bios_reboot,
 355                 .ident = "Sony VGN-Z540N",
 356                 .matches = {
 357                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 358                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 359                 },
 360         },
 361         {       /* Handle problems with rebooting on CompuLab SBC-FITPC2 */
 362                 .callback = set_bios_reboot,
 363                 .ident = "CompuLab SBC-FITPC2",
 364                 .matches = {
 365                         DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
 366                         DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
 367                 },
 368         },
 369         {       /* Handle problems with rebooting on ASUS P4S800 */
 370                 .callback = set_bios_reboot,
 371                 .ident = "ASUS P4S800",
 372                 .matches = {
 373                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 374                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 375                 },
 376         },
 377
 378         {       /* Handle reboot issue on Acer Aspire one */
 379                 .callback = set_kbd_reboot,
 380                 .ident = "Acer Aspire One A110",
 381                 .matches = {
 382                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 383                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 384                 },
 385         },
 386         {       /* Handle problems with rebooting on Apple MacBook5 */
 387                 .callback = set_pci_reboot,
 388                 .ident = "Apple MacBook5",
 389                 .matches = {
 390                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 391                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 392                 },
 393         },
 394         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 395                 .callback = set_pci_reboot,
 396                 .ident = "Apple MacBookPro5",
 397                 .matches = {
 398                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 399                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 400                 },
 401         },
 402         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 403                 .callback = set_pci_reboot,
 404                 .ident = "Apple Macmini3,1",
 405                 .matches = {
 406                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 407                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 408                 },
 409         },
 410         {       /* Handle problems with rebooting on the iMac9,1. */
 411                 .callback = set_pci_reboot,
 412                 .ident = "Apple iMac9,1",
 413                 .matches = {
 414                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 415                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 416                 },
 417         },
 418         {       /* Handle problems with rebooting on the Latitude E6320. */
 419                 .callback = set_pci_reboot,
 420                 .ident = "Dell Latitude E6320",
 421                 .matches = {
 422                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 423                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 424                 },
 425         },
 426         {       /* Handle problems with rebooting on the Latitude E5420. */
 427                 .callback = set_pci_reboot,
 428                 .ident = "Dell Latitude E5420",
 429                 .matches = {
 430                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 431                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 432                 },
 433         },
 434         {       /* Handle problems with rebooting on the Latitude E6420. */
 435                 .callback = set_pci_reboot,
 436                 .ident = "Dell Latitude E6420",
 437                 .matches = {
 438                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 439                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 440                 },
 441         },
 442         {       /* Handle problems with rebooting on the OptiPlex 990. */
 443                 .callback = set_pci_reboot,
 444                 .ident = "Dell OptiPlex 990",
 445                 .matches = {
 446                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 447                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 448                 },
 449         },
 450         {       /* Handle problems with rebooting on the Precision M6600. */
 451                 .callback = set_pci_reboot,
 452                 .ident = "Dell OptiPlex 990",
 453                 .matches = {
 454                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 455                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 456                 },
 457         },
 458         { }
 459 };
 460
 461 static int __init reboot_init(void)
 462 {
 463         /*
 464          * Only do the DMI check if reboot_type hasn't been overridden
 465          * on the command line
 466          */
 467         if (reboot_default)
 468                 dmi_check_system(reboot_dmi_table);
 469         return 0;
 470 }
 471 core_initcall(reboot_init);
 472
 473 static inline void kb_wait(void)
 474 {
 475         int i;
 476
 477         for (i = 0; i < 0x10000; i++) {
 478                 if ((inb(0x64) & 0x02) == 0)
 479                         break;
 480                 udelay(2);
 481         }
 482 }
 483
 484 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 485 {
 486         cpu_emergency_vmxoff();
 487 }
 488
 489 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 490 static void emergency_vmx_disable_all(void)
 491 {
 492         /* Just make sure we won't change CPUs while doing this */
 493         local_irq_disable();
 494
 495         /*
 496          * We need to disable VMX on all CPUs before rebooting, otherwise
 497          * we risk hanging up the machine, because the CPU ignore INIT
 498          * signals when VMX is enabled.
 499          *
 500          * We can't take any locks and we may be on an inconsistent
 501          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 502          * VMX and halt.
 503          *
 504          * For safety, we will avoid running the nmi_shootdown_cpus()
 505          * stuff unnecessarily, but we don't have a way to check
 506          * if other CPUs have VMX enabled. So we will call it only if the
 507          * CPU we are running on has VMX enabled.
 508          *
 509          * We will miss cases where VMX is not enabled on all CPUs. This
 510          * shouldn't do much harm because KVM always enable VMX on all
 511          * CPUs anyway. But we can miss it on the small window where KVM
 512          * is still enabling VMX.
 513          */
 514         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 515                 /* Disable VMX on this CPU. */
 516                 cpu_vmxoff();
 517
 518                 /* Halt and disable VMX on the other CPUs */
 519                 nmi_shootdown_cpus(vmxoff_nmi);
 520
 521         }
 522 }
 523
 524
 525 void __attribute__((weak)) mach_reboot_fixups(void)
 526 {
 527 }
 528
 529 /*
 530  * Windows compatible x86 hardware expects the following on reboot:
 531  *
 532  * 1) If the FADT has the ACPI reboot register flag set, try it
 533  * 2) If still alive, write to the keyboard controller
 534  * 3) If still alive, write to the ACPI reboot register again
 535  * 4) If still alive, write to the keyboard controller again
 536  *
 537  * If the machine is still alive at this stage, it gives up. We default to
 538  * following the same pattern, except that if we're still alive after (4) we'll
 539  * try to force a triple fault and then cycle between hitting the keyboard
 540  * controller and doing that
 541  */
 542 static void native_machine_emergency_restart(void)
 543 {
 544         int i;
 545         int attempt = 0;
 546         int orig_reboot_type = reboot_type;
 547
 548         if (reboot_emergency)
 549                 emergency_vmx_disable_all();
 550
 551         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 552
 553         /* Tell the BIOS if we want cold or warm reboot */
 554         *((unsigned short *)__va(0x472)) = reboot_mode;
 555
 556         for (;;) {
 557                 /* Could also try the reset bit in the Hammer NB */
 558                 switch (reboot_type) {
 559                 case BOOT_KBD:
 560                         mach_reboot_fixups(); /* For board specific fixups */
 561
 562                         for (i = 0; i < 10; i++) {
 563                                 kb_wait();
 564                                 udelay(50);
 565                                 outb(0xfe, 0x64); /* Pulse reset low */
 566                                 udelay(50);
 567                         }
 568                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 569                                 attempt = 1;
 570                                 reboot_type = BOOT_ACPI;
 571                         } else {
 572                                 reboot_type = BOOT_TRIPLE;
 573                         }
 574                         break;
 575
 576                 case BOOT_TRIPLE:
 577                         load_idt(&no_idt);
 578                         __asm__ __volatile__("int3");
 579
 580                         reboot_type = BOOT_KBD;
 581                         break;
 582
 583                 case BOOT_BIOS:
 584                         machine_real_restart(MRR_BIOS);
 585
 586                         reboot_type = BOOT_KBD;
 587                         break;
 588
 589                 case BOOT_ACPI:
 590                         acpi_reboot();
 591                         reboot_type = BOOT_KBD;
 592                         break;
 593
 594                 case BOOT_EFI:
 595                         if (efi_enabled)
 596                                 efi.reset_system(reboot_mode ?
 597                                                  EFI_RESET_WARM :
 598                                                  EFI_RESET_COLD,
 599                                                  EFI_SUCCESS, 0, NULL);
 600                         reboot_type = BOOT_KBD;
 601                         break;
 602
 603                 case BOOT_CF9:
 604                         port_cf9_safe = true;
 605                         /* Fall through */
 606
 607                 case BOOT_CF9_COND:
 608                         if (port_cf9_safe) {
 609                                 u8 cf9 = inb(0xcf9) & ~6;
 610                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 611                                 udelay(50);
 612                                 outb(cf9|6, 0xcf9); /* Actually do the reset */
 613                                 udelay(50);
 614                         }
 615                         reboot_type = BOOT_KBD;
 616                         break;
 617                 }
 618         }
 619 }
 620
 621 void native_machine_shutdown(void)
 622 {
 623         /* Stop the cpus and apics */
 624 #ifdef CONFIG_SMP
 625
 626         /* The boot cpu is always logical cpu 0 */
 627         int reboot_cpu_id = 0;
 628
 629         /* See if there has been given a command line override */
 630         if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
 631                 cpu_online(reboot_cpu))
 632                 reboot_cpu_id = reboot_cpu;
 633
 634         /* Make certain the cpu I'm about to reboot on is online */
 635         if (!cpu_online(reboot_cpu_id))
 636                 reboot_cpu_id = smp_processor_id();
 637
 638         /* Make certain I only run on the appropriate processor */
 639         set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
 640
 641         /*
 642          * O.K Now that I'm on the appropriate processor, stop all of the
 643          * others. Also disable the local irq to not receive the per-cpu
 644          * timer interrupt which may trigger scheduler's load balance.
 645          */
 646         local_irq_disable();
 647         stop_other_cpus();
 648 #endif
 649
 650         lapic_shutdown();
 651
 652 #ifdef CONFIG_X86_IO_APIC
 653         disable_IO_APIC();
 654 #endif
 655
 656 #ifdef CONFIG_HPET_TIMER
 657         hpet_disable();
 658 #endif
 659
 660 #ifdef CONFIG_X86_64
 661         x86_platform.iommu_shutdown();
 662 #endif
 663 }
 664
 665 static void __machine_emergency_restart(int emergency)
 666 {
 667         reboot_emergency = emergency;
 668         machine_ops.emergency_restart();
 669 }
 670
 671 static void native_machine_restart(char *__unused)
 672 {
 673         pr_notice("machine restart\n");
 674
 675         if (!reboot_force)
 676                 machine_shutdown();
 677         __machine_emergency_restart(0);
 678 }
 679
 680 static void native_machine_halt(void)
 681 {
 682         /* Stop other cpus and apics */
 683         machine_shutdown();
 684
 685         tboot_shutdown(TB_SHUTDOWN_HALT);
 686
 687         stop_this_cpu(NULL);
 688 }
 689
 690 static void native_machine_power_off(void)
 691 {
 692         if (pm_power_off) {
 693                 if (!reboot_force)
 694                         machine_shutdown();
 695                 pm_power_off();
 696         }
 697         /* A fallback in case there is no PM info available */
 698         tboot_shutdown(TB_SHUTDOWN_HALT);
 699 }
 700
 701 struct machine_ops machine_ops = {
 702         .power_off = native_machine_power_off,
 703         .shutdown = native_machine_shutdown,
 704         .emergency_restart = native_machine_emergency_restart,
 705         .restart = native_machine_restart,
 706         .halt = native_machine_halt,
 707 #ifdef CONFIG_KEXEC
 708         .crash_shutdown = native_machine_crash_shutdown,
 709 #endif
 710 };
 711
 712 void machine_power_off(void)
 713 {
 714         machine_ops.power_off();
 715 }
 716
 717 void machine_shutdown(void)
 718 {
 719         machine_ops.shutdown();
 720 }
 721
 722 void machine_emergency_restart(void)
 723 {
 724         __machine_emergency_restart(1);
 725 }
 726
 727 void machine_restart(char *cmd)
 728 {
 729         machine_ops.restart(cmd);
 730 }
 731
 732 void machine_halt(void)
 733 {
 734         machine_ops.halt();
 735 }
 736
 737 #ifdef CONFIG_KEXEC
 738 void machine_crash_shutdown(struct pt_regs *regs)
 739 {
 740         machine_ops.crash_shutdown(regs);
 741 }
 742 #endif
 743
 744
 745 #if defined(CONFIG_SMP)
 746
 747 /* This keeps a track of which one is crashing cpu. */
 748 static int crashing_cpu;
 749 static nmi_shootdown_cb shootdown_callback;
 750
 751 static atomic_t waiting_for_crash_ipi;
 752
 753 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 754 {
 755         int cpu;
 756
 757         cpu = raw_smp_processor_id();
 758
 759         /*
 760          * Don't do anything if this handler is invoked on crashing cpu.
 761          * Otherwise, system will completely hang. Crashing cpu can get
 762          * an NMI if system was initially booted with nmi_watchdog parameter.
 763          */
 764         if (cpu == crashing_cpu)
 765                 return NMI_HANDLED;
 766         local_irq_disable();
 767
 768         shootdown_callback(cpu, regs);
 769
 770         atomic_dec(&waiting_for_crash_ipi);
 771         /* Assume hlt works */
 772         halt();
 773         for (;;)
 774                 cpu_relax();
 775
 776         return NMI_HANDLED;
 777 }
 778
 779 static void smp_send_nmi_allbutself(void)
 780 {
 781         apic->send_IPI_allbutself(NMI_VECTOR);
 782 }
 783
 784 /*
 785  * Halt all other CPUs, calling the specified function on each of them
 786  *
 787  * This function can be used to halt all other CPUs on crash
 788  * or emergency reboot time. The function passed as parameter
 789  * will be called inside a NMI handler on all CPUs.
 790  */
 791 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 792 {
 793         unsigned long msecs;
 794         local_irq_disable();
 795
 796         /* Make a note of crashing cpu. Will be used in NMI callback. */
 797         crashing_cpu = safe_smp_processor_id();
 798
 799         shootdown_callback = callback;
 800
 801         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 802         /* Would it be better to replace the trap vector here? */
 803         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 804                                  NMI_FLAG_FIRST, "crash"))
 805                 return;         /* Return what? */
 806         /*
 807          * Ensure the new callback function is set before sending
 808          * out the NMI
 809          */
 810         wmb();
 811
 812         smp_send_nmi_allbutself();
 813
 814         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 815         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 816                 mdelay(1);
 817                 msecs--;
 818         }
 819
 820         /* Leave the nmi callback set */
 821 }
 822 #else /* !CONFIG_SMP */
 823 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 824 {
 825         /* No other CPUs to shoot down */
 826 }
 827 #endif