arch/x86/kernel/reboot.c

   1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   2
   3 #include <linux/module.h>
   4 #include <linux/reboot.h>
   5 #include <linux/init.h>
   6 #include <linux/pm.h>
   7 #include <linux/efi.h>
   8 #include <linux/dmi.h>
   9 #include <linux/sched.h>
  10 #include <linux/tboot.h>
  11 #include <linux/delay.h>
  12 #include <acpi/reboot.h>
  13 #include <asm/io.h>
  14 #include <asm/apic.h>
  15 #include <asm/desc.h>
  16 #include <asm/hpet.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/proto.h>
  19 #include <asm/reboot_fixups.h>
  20 #include <asm/reboot.h>
  21 #include <asm/pci_x86.h>
  22 #include <asm/virtext.h>
  23 #include <asm/cpu.h>
  24 #include <asm/nmi.h>
  25 #include <asm/smp.h>
  26
  27 #include <linux/ctype.h>
  28 #include <linux/mc146818rtc.h>
  29 #include <asm/realmode.h>
  30 #include <asm/x86_init.h>
  31
  32 /*
  33  * Power off function, if any
  34  */
  35 void (*pm_power_off)(void);
  36 EXPORT_SYMBOL(pm_power_off);
  37
  38 static const struct desc_ptr no_idt = {};
  39
  40 /*
  41  * This is set if we need to go through the 'emergency' path.
  42  * When machine_emergency_restart() is called, we may be on
  43  * an inconsistent state and won't be able to do a clean cleanup
  44  */
  45 static int reboot_emergency;
  46
  47 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  48 bool port_cf9_safe = false;
  49
  50 /*
  51  * Reboot options and system auto-detection code provided by
  52  * Dell Inc. so their systems "just work". :-)
  53  */
  54
  55 /*
  56  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  57  * this quirk makes that automatic.
  58  */
  59 static int __init set_bios_reboot(const struct dmi_system_id *d)
  60 {
  61         if (reboot_type != BOOT_BIOS) {
  62                 reboot_type = BOOT_BIOS;
  63                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  64                         "BIOS", d->ident);
  65         }
  66         return 0;
  67 }
  68
  69 void __noreturn machine_real_restart(unsigned int type)
  70 {
  71         local_irq_disable();
  72
  73         /*
  74          * Write zero to CMOS register number 0x0f, which the BIOS POST
  75          * routine will recognize as telling it to do a proper reboot.  (Well
  76          * that's what this book in front of me says -- it may only apply to
  77          * the Phoenix BIOS though, it's not clear).  At the same time,
  78          * disable NMIs by setting the top bit in the CMOS address register,
  79          * as we're about to do peculiar things to the CPU.  I'm not sure if
  80          * `outb_p' is needed instead of just `outb'.  Use it to be on the
  81          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
  82          */
  83         spin_lock(&rtc_lock);
  84         CMOS_WRITE(0x00, 0x8f);
  85         spin_unlock(&rtc_lock);
  86
  87         /*
  88          * Switch back to the initial page table.
  89          */
  90 #ifdef CONFIG_X86_32
  91         load_cr3(initial_page_table);
  92 #else
  93         write_cr3(real_mode_header->trampoline_pgd);
  94 #endif
  95
  96         /* Jump to the identity-mapped low memory code */
  97 #ifdef CONFIG_X86_32
  98         asm volatile("jmpl *%0" : :
  99                      "rm" (real_mode_header->machine_real_restart_asm),
 100                      "a" (type));
 101 #else
 102         asm volatile("ljmpl *%0" : :
 103                      "m" (real_mode_header->machine_real_restart_asm),
 104                      "D" (type));
 105 #endif
 106         unreachable();
 107 }
 108 #ifdef CONFIG_APM_MODULE
 109 EXPORT_SYMBOL(machine_real_restart);
 110 #endif
 111
 112 /*
 113  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 114  */
 115 static int __init set_pci_reboot(const struct dmi_system_id *d)
 116 {
 117         if (reboot_type != BOOT_CF9) {
 118                 reboot_type = BOOT_CF9;
 119                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 120                         "PCI", d->ident);
 121         }
 122         return 0;
 123 }
 124
 125 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 126 {
 127         if (reboot_type != BOOT_KBD) {
 128                 reboot_type = BOOT_KBD;
 129                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 130                         "KBD", d->ident);
 131         }
 132         return 0;
 133 }
 134
 135 /*
 136  * This is a single dmi_table handling all reboot quirks.
 137  */
 138 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 139         {       /* Handle problems with rebooting on Dell E520's */
 140                 .callback = set_bios_reboot,
 141                 .ident = "Dell E520",
 142                 .matches = {
 143                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 144                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 145                 },
 146         },
 147         {       /* Handle problems with rebooting on Dell 1300's */
 148                 .callback = set_bios_reboot,
 149                 .ident = "Dell PowerEdge 1300",
 150                 .matches = {
 151                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 152                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 153                 },
 154         },
 155         {       /* Handle problems with rebooting on Dell 300's */
 156                 .callback = set_bios_reboot,
 157                 .ident = "Dell PowerEdge 300",
 158                 .matches = {
 159                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 160                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 161                 },
 162         },
 163         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 164                 .callback = set_bios_reboot,
 165                 .ident = "Dell OptiPlex 745",
 166                 .matches = {
 167                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 168                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 169                 },
 170         },
 171         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 172                 .callback = set_bios_reboot,
 173                 .ident = "Dell OptiPlex 745",
 174                 .matches = {
 175                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 176                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 177                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 178                 },
 179         },
 180         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 181                 .callback = set_bios_reboot,
 182                 .ident = "Dell OptiPlex 745",
 183                 .matches = {
 184                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 185                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 186                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 187                 },
 188         },
 189         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 190                 .callback = set_bios_reboot,
 191                 .ident = "Dell OptiPlex 330",
 192                 .matches = {
 193                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 194                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 195                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 196                 },
 197         },
 198         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 199                 .callback = set_bios_reboot,
 200                 .ident = "Dell OptiPlex 360",
 201                 .matches = {
 202                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 203                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 204                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 205                 },
 206         },
 207         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 208                 .callback = set_bios_reboot,
 209                 .ident = "Dell OptiPlex 760",
 210                 .matches = {
 211                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 212                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 213                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 214                 },
 215         },
 216         {       /* Handle problems with rebooting on Dell 2400's */
 217                 .callback = set_bios_reboot,
 218                 .ident = "Dell PowerEdge 2400",
 219                 .matches = {
 220                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 221                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 222                 },
 223         },
 224         {       /* Handle problems with rebooting on Dell T5400's */
 225                 .callback = set_bios_reboot,
 226                 .ident = "Dell Precision T5400",
 227                 .matches = {
 228                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 229                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 230                 },
 231         },
 232         {       /* Handle problems with rebooting on Dell T7400's */
 233                 .callback = set_bios_reboot,
 234                 .ident = "Dell Precision T7400",
 235                 .matches = {
 236                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 237                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 238                 },
 239         },
 240         {       /* Handle problems with rebooting on HP laptops */
 241                 .callback = set_bios_reboot,
 242                 .ident = "HP Compaq Laptop",
 243                 .matches = {
 244                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 245                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 246                 },
 247         },
 248         {       /* Handle problems with rebooting on Dell XPS710 */
 249                 .callback = set_bios_reboot,
 250                 .ident = "Dell XPS710",
 251                 .matches = {
 252                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 253                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 254                 },
 255         },
 256         {       /* Handle problems with rebooting on Dell DXP061 */
 257                 .callback = set_bios_reboot,
 258                 .ident = "Dell DXP061",
 259                 .matches = {
 260                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 261                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 262                 },
 263         },
 264         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 265                 .callback = set_bios_reboot,
 266                 .ident = "Sony VGN-Z540N",
 267                 .matches = {
 268                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 269                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 270                 },
 271         },
 272         {       /* Handle problems with rebooting on ASUS P4S800 */
 273                 .callback = set_bios_reboot,
 274                 .ident = "ASUS P4S800",
 275                 .matches = {
 276                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 277                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 278                 },
 279         },
 280
 281         {       /* Handle reboot issue on Acer Aspire one */
 282                 .callback = set_kbd_reboot,
 283                 .ident = "Acer Aspire One A110",
 284                 .matches = {
 285                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 286                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 287                 },
 288         },
 289         {       /* Handle problems with rebooting on Apple MacBook5 */
 290                 .callback = set_pci_reboot,
 291                 .ident = "Apple MacBook5",
 292                 .matches = {
 293                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 294                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 295                 },
 296         },
 297         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 298                 .callback = set_pci_reboot,
 299                 .ident = "Apple MacBookPro5",
 300                 .matches = {
 301                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 302                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 303                 },
 304         },
 305         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 306                 .callback = set_pci_reboot,
 307                 .ident = "Apple Macmini3,1",
 308                 .matches = {
 309                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 310                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 311                 },
 312         },
 313         {       /* Handle problems with rebooting on the iMac9,1. */
 314                 .callback = set_pci_reboot,
 315                 .ident = "Apple iMac9,1",
 316                 .matches = {
 317                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 318                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 319                 },
 320         },
 321         {       /* Handle problems with rebooting on the Latitude E6320. */
 322                 .callback = set_pci_reboot,
 323                 .ident = "Dell Latitude E6320",
 324                 .matches = {
 325                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 326                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 327                 },
 328         },
 329         {       /* Handle problems with rebooting on the Latitude E5420. */
 330                 .callback = set_pci_reboot,
 331                 .ident = "Dell Latitude E5420",
 332                 .matches = {
 333                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 334                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 335                 },
 336         },
 337         {       /* Handle problems with rebooting on the Latitude E6420. */
 338                 .callback = set_pci_reboot,
 339                 .ident = "Dell Latitude E6420",
 340                 .matches = {
 341                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 342                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 343                 },
 344         },
 345         {       /* Handle problems with rebooting on the OptiPlex 990. */
 346                 .callback = set_pci_reboot,
 347                 .ident = "Dell OptiPlex 990",
 348                 .matches = {
 349                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 350                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 351                 },
 352         },
 353         {       /* Handle problems with rebooting on the Precision M6600. */
 354                 .callback = set_pci_reboot,
 355                 .ident = "Dell OptiPlex 990",
 356                 .matches = {
 357                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 358                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 359                 },
 360         },
 361         { }
 362 };
 363
 364 static int __init reboot_init(void)
 365 {
 366         /*
 367          * Only do the DMI check if reboot_type hasn't been overridden
 368          * on the command line
 369          */
 370         if (reboot_default)
 371                 dmi_check_system(reboot_dmi_table);
 372         return 0;
 373 }
 374 core_initcall(reboot_init);
 375
 376 static inline void kb_wait(void)
 377 {
 378         int i;
 379
 380         for (i = 0; i < 0x10000; i++) {
 381                 if ((inb(0x64) & 0x02) == 0)
 382                         break;
 383                 udelay(2);
 384         }
 385 }
 386
 387 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 388 {
 389         cpu_emergency_vmxoff();
 390 }
 391
 392 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 393 static void emergency_vmx_disable_all(void)
 394 {
 395         /* Just make sure we won't change CPUs while doing this */
 396         local_irq_disable();
 397
 398         /*
 399          * We need to disable VMX on all CPUs before rebooting, otherwise
 400          * we risk hanging up the machine, because the CPU ignore INIT
 401          * signals when VMX is enabled.
 402          *
 403          * We can't take any locks and we may be on an inconsistent
 404          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 405          * VMX and halt.
 406          *
 407          * For safety, we will avoid running the nmi_shootdown_cpus()
 408          * stuff unnecessarily, but we don't have a way to check
 409          * if other CPUs have VMX enabled. So we will call it only if the
 410          * CPU we are running on has VMX enabled.
 411          *
 412          * We will miss cases where VMX is not enabled on all CPUs. This
 413          * shouldn't do much harm because KVM always enable VMX on all
 414          * CPUs anyway. But we can miss it on the small window where KVM
 415          * is still enabling VMX.
 416          */
 417         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 418                 /* Disable VMX on this CPU. */
 419                 cpu_vmxoff();
 420
 421                 /* Halt and disable VMX on the other CPUs */
 422                 nmi_shootdown_cpus(vmxoff_nmi);
 423
 424         }
 425 }
 426
 427
 428 void __attribute__((weak)) mach_reboot_fixups(void)
 429 {
 430 }
 431
 432 /*
 433  * Windows compatible x86 hardware expects the following on reboot:
 434  *
 435  * 1) If the FADT has the ACPI reboot register flag set, try it
 436  * 2) If still alive, write to the keyboard controller
 437  * 3) If still alive, write to the ACPI reboot register again
 438  * 4) If still alive, write to the keyboard controller again
 439  *
 440  * If the machine is still alive at this stage, it gives up. We default to
 441  * following the same pattern, except that if we're still alive after (4) we'll
 442  * try to force a triple fault and then cycle between hitting the keyboard
 443  * controller and doing that
 444  */
 445 static void native_machine_emergency_restart(void)
 446 {
 447         int i;
 448         int attempt = 0;
 449         int orig_reboot_type = reboot_type;
 450         unsigned short mode;
 451
 452         if (reboot_emergency)
 453                 emergency_vmx_disable_all();
 454
 455         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 456
 457         /* Tell the BIOS if we want cold or warm reboot */
 458         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 459         *((unsigned short *)__va(0x472)) = mode;
 460
 461         for (;;) {
 462                 /* Could also try the reset bit in the Hammer NB */
 463                 switch (reboot_type) {
 464                 case BOOT_KBD:
 465                         mach_reboot_fixups(); /* For board specific fixups */
 466
 467                         for (i = 0; i < 10; i++) {
 468                                 kb_wait();
 469                                 udelay(50);
 470                                 outb(0xfe, 0x64); /* Pulse reset low */
 471                                 udelay(50);
 472                         }
 473                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 474                                 attempt = 1;
 475                                 reboot_type = BOOT_ACPI;
 476                         } else {
 477                                 reboot_type = BOOT_TRIPLE;
 478                         }
 479                         break;
 480
 481                 case BOOT_TRIPLE:
 482                         load_idt(&no_idt);
 483                         __asm__ __volatile__("int3");
 484
 485                         reboot_type = BOOT_KBD;
 486                         break;
 487
 488                 case BOOT_BIOS:
 489                         machine_real_restart(MRR_BIOS);
 490
 491                         reboot_type = BOOT_KBD;
 492                         break;
 493
 494                 case BOOT_ACPI:
 495                         acpi_reboot();
 496                         reboot_type = BOOT_KBD;
 497                         break;
 498
 499                 case BOOT_EFI:
 500                         if (efi_enabled(EFI_RUNTIME_SERVICES))
 501                                 efi.reset_system(reboot_mode == REBOOT_WARM ?
 502                                                  EFI_RESET_WARM :
 503                                                  EFI_RESET_COLD,
 504                                                  EFI_SUCCESS, 0, NULL);
 505                         reboot_type = BOOT_KBD;
 506                         break;
 507
 508                 case BOOT_CF9:
 509                         port_cf9_safe = true;
 510                         /* Fall through */
 511
 512                 case BOOT_CF9_COND:
 513                         if (port_cf9_safe) {
 514                                 u8 cf9 = inb(0xcf9) & ~6;
 515                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 516                                 udelay(50);
 517                                 outb(cf9|6, 0xcf9); /* Actually do the reset */
 518                                 udelay(50);
 519                         }
 520                         reboot_type = BOOT_KBD;
 521                         break;
 522                 }
 523         }
 524 }
 525
 526 void native_machine_shutdown(void)
 527 {
 528         /* Stop the cpus and apics */
 529 #ifdef CONFIG_SMP
 530         /*
 531          * Stop all of the others. Also disable the local irq to
 532          * not receive the per-cpu timer interrupt which may trigger
 533          * scheduler's load balance.
 534          */
 535         local_irq_disable();
 536         stop_other_cpus();
 537 #endif
 538
 539         lapic_shutdown();
 540
 541 #ifdef CONFIG_X86_IO_APIC
 542         disable_IO_APIC();
 543 #endif
 544
 545 #ifdef CONFIG_HPET_TIMER
 546         hpet_disable();
 547 #endif
 548
 549 #ifdef CONFIG_X86_64
 550         x86_platform.iommu_shutdown();
 551 #endif
 552 }
 553
 554 static void __machine_emergency_restart(int emergency)
 555 {
 556         reboot_emergency = emergency;
 557         machine_ops.emergency_restart();
 558 }
 559
 560 static void native_machine_restart(char *__unused)
 561 {
 562         pr_notice("machine restart\n");
 563
 564         if (!reboot_force)
 565                 machine_shutdown();
 566         __machine_emergency_restart(0);
 567 }
 568
 569 static void native_machine_halt(void)
 570 {
 571         /* Stop other cpus and apics */
 572         machine_shutdown();
 573
 574         tboot_shutdown(TB_SHUTDOWN_HALT);
 575
 576         stop_this_cpu(NULL);
 577 }
 578
 579 static void native_machine_power_off(void)
 580 {
 581         if (pm_power_off) {
 582                 if (!reboot_force)
 583                         machine_shutdown();
 584                 pm_power_off();
 585         }
 586         /* A fallback in case there is no PM info available */
 587         tboot_shutdown(TB_SHUTDOWN_HALT);
 588 }
 589
 590 struct machine_ops machine_ops = {
 591         .power_off = native_machine_power_off,
 592         .shutdown = native_machine_shutdown,
 593         .emergency_restart = native_machine_emergency_restart,
 594         .restart = native_machine_restart,
 595         .halt = native_machine_halt,
 596 #ifdef CONFIG_KEXEC
 597         .crash_shutdown = native_machine_crash_shutdown,
 598 #endif
 599 };
 600
 601 void machine_power_off(void)
 602 {
 603         machine_ops.power_off();
 604 }
 605
 606 void machine_shutdown(void)
 607 {
 608         machine_ops.shutdown();
 609 }
 610
 611 void machine_emergency_restart(void)
 612 {
 613         __machine_emergency_restart(1);
 614 }
 615
 616 void machine_restart(char *cmd)
 617 {
 618         machine_ops.restart(cmd);
 619 }
 620
 621 void machine_halt(void)
 622 {
 623         machine_ops.halt();
 624 }
 625
 626 #ifdef CONFIG_KEXEC
 627 void machine_crash_shutdown(struct pt_regs *regs)
 628 {
 629         machine_ops.crash_shutdown(regs);
 630 }
 631 #endif
 632
 633
 634 #if defined(CONFIG_SMP)
 635
 636 /* This keeps a track of which one is crashing cpu. */
 637 static int crashing_cpu;
 638 static nmi_shootdown_cb shootdown_callback;
 639
 640 static atomic_t waiting_for_crash_ipi;
 641
 642 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 643 {
 644         int cpu;
 645
 646         cpu = raw_smp_processor_id();
 647
 648         /*
 649          * Don't do anything if this handler is invoked on crashing cpu.
 650          * Otherwise, system will completely hang. Crashing cpu can get
 651          * an NMI if system was initially booted with nmi_watchdog parameter.
 652          */
 653         if (cpu == crashing_cpu)
 654                 return NMI_HANDLED;
 655         local_irq_disable();
 656
 657         shootdown_callback(cpu, regs);
 658
 659         atomic_dec(&waiting_for_crash_ipi);
 660         /* Assume hlt works */
 661         halt();
 662         for (;;)
 663                 cpu_relax();
 664
 665         return NMI_HANDLED;
 666 }
 667
 668 static void smp_send_nmi_allbutself(void)
 669 {
 670         apic->send_IPI_allbutself(NMI_VECTOR);
 671 }
 672
 673 /*
 674  * Halt all other CPUs, calling the specified function on each of them
 675  *
 676  * This function can be used to halt all other CPUs on crash
 677  * or emergency reboot time. The function passed as parameter
 678  * will be called inside a NMI handler on all CPUs.
 679  */
 680 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 681 {
 682         unsigned long msecs;
 683         local_irq_disable();
 684
 685         /* Make a note of crashing cpu. Will be used in NMI callback. */
 686         crashing_cpu = safe_smp_processor_id();
 687
 688         shootdown_callback = callback;
 689
 690         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 691         /* Would it be better to replace the trap vector here? */
 692         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 693                                  NMI_FLAG_FIRST, "crash"))
 694                 return;         /* Return what? */
 695         /*
 696          * Ensure the new callback function is set before sending
 697          * out the NMI
 698          */
 699         wmb();
 700
 701         smp_send_nmi_allbutself();
 702
 703         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 704         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 705                 mdelay(1);
 706                 msecs--;
 707         }
 708
 709         /* Leave the nmi callback set */
 710 }
 711 #else /* !CONFIG_SMP */
 712 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 713 {
 714         /* No other CPUs to shoot down */
 715 }
 716 #endif