arch/x86/kernel/reboot.c

   1 #include <linux/module.h>
   2 #include <linux/reboot.h>
   3 #include <linux/init.h>
   4 #include <linux/pm.h>
   5 #include <linux/efi.h>
   6 #include <linux/dmi.h>
   7 #include <linux/tboot.h>
   8 #include <acpi/reboot.h>
   9 #include <asm/io.h>
  10 #include <asm/apic.h>
  11 #include <asm/desc.h>
  12 #include <asm/hpet.h>
  13 #include <asm/pgtable.h>
  14 #include <asm/proto.h>
  15 #include <asm/reboot_fixups.h>
  16 #include <asm/reboot.h>
  17 #include <asm/pci_x86.h>
  18 #include <asm/virtext.h>
  19 #include <asm/cpu.h>
  20
  21 #ifdef CONFIG_X86_32
  22 # include <linux/ctype.h>
  23 # include <linux/mc146818rtc.h>
  24 #else
  25 # include <asm/iommu.h>
  26 #endif
  27
  28 /*
  29  * Power off function, if any
  30  */
  31 void (*pm_power_off)(void);
  32 EXPORT_SYMBOL(pm_power_off);
  33
  34 static const struct desc_ptr no_idt = {};
  35 static int reboot_mode;
  36 enum reboot_type reboot_type = BOOT_KBD;
  37 int reboot_force;
  38
  39 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
  40 static int reboot_cpu = -1;
  41 #endif
  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 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
  53    warm   Don't set the cold reboot flag
  54    cold   Set the cold reboot flag
  55    bios   Reboot by jumping through the BIOS (only for X86_32)
  56    smp    Reboot by executing reset on BSP or other CPU (only for X86_32)
  57    triple Force a triple fault (init)
  58    kbd    Use the keyboard controller. cold reset (default)
  59    acpi   Use the RESET_REG in the FADT
  60    efi    Use efi reset_system runtime service
  61    pci    Use the so-called "PCI reset register", CF9
  62    force  Avoid anything that could hang.
  63  */
  64 static int __init reboot_setup(char *str)
  65 {
  66         for (;;) {
  67                 switch (*str) {
  68                 case 'w':
  69                         reboot_mode = 0x1234;
  70                         break;
  71
  72                 case 'c':
  73                         reboot_mode = 0;
  74                         break;
  75
  76 #ifdef CONFIG_X86_32
  77 #ifdef CONFIG_SMP
  78                 case 's':
  79                         if (isdigit(*(str+1))) {
  80                                 reboot_cpu = (int) (*(str+1) - '0');
  81                                 if (isdigit(*(str+2)))
  82                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
  83                         }
  84                                 /* we will leave sorting out the final value
  85                                    when we are ready to reboot, since we might not
  86                                    have set up boot_cpu_id or smp_num_cpu */
  87                         break;
  88 #endif /* CONFIG_SMP */
  89
  90                 case 'b':
  91 #endif
  92                 case 'a':
  93                 case 'k':
  94                 case 't':
  95                 case 'e':
  96                 case 'p':
  97                         reboot_type = *str;
  98                         break;
  99
 100                 case 'f':
 101                         reboot_force = 1;
 102                         break;
 103                 }
 104
 105                 str = strchr(str, ',');
 106                 if (str)
 107                         str++;
 108                 else
 109                         break;
 110         }
 111         return 1;
 112 }
 113
 114 __setup("reboot=", reboot_setup);
 115
 116
 117 #ifdef CONFIG_X86_32
 118 /*
 119  * Reboot options and system auto-detection code provided by
 120  * Dell Inc. so their systems "just work". :-)
 121  */
 122
 123 /*
 124  * Some machines require the "reboot=b"  commandline option,
 125  * this quirk makes that automatic.
 126  */
 127 static int __init set_bios_reboot(const struct dmi_system_id *d)
 128 {
 129         if (reboot_type != BOOT_BIOS) {
 130                 reboot_type = BOOT_BIOS;
 131                 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
 132         }
 133         return 0;
 134 }
 135
 136 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 137         {       /* Handle problems with rebooting on Dell E520's */
 138                 .callback = set_bios_reboot,
 139                 .ident = "Dell E520",
 140                 .matches = {
 141                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 142                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 143                 },
 144         },
 145         {       /* Handle problems with rebooting on Dell 1300's */
 146                 .callback = set_bios_reboot,
 147                 .ident = "Dell PowerEdge 1300",
 148                 .matches = {
 149                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 150                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 151                 },
 152         },
 153         {       /* Handle problems with rebooting on Dell 300's */
 154                 .callback = set_bios_reboot,
 155                 .ident = "Dell PowerEdge 300",
 156                 .matches = {
 157                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 158                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 159                 },
 160         },
 161         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF*/
 162                 .callback = set_bios_reboot,
 163                 .ident = "Dell OptiPlex 745",
 164                 .matches = {
 165                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 166                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 167                 },
 168         },
 169         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF*/
 170                 .callback = set_bios_reboot,
 171                 .ident = "Dell OptiPlex 745",
 172                 .matches = {
 173                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 174                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 175                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 176                 },
 177         },
 178         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 179                 .callback = set_bios_reboot,
 180                 .ident = "Dell OptiPlex 745",
 181                 .matches = {
 182                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 183                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 184                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 185                 },
 186         },
 187         {   /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 188                 .callback = set_bios_reboot,
 189                 .ident = "Dell OptiPlex 330",
 190                 .matches = {
 191                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 192                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 193                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 194                 },
 195         },
 196         {   /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 197                 .callback = set_bios_reboot,
 198                 .ident = "Dell OptiPlex 360",
 199                 .matches = {
 200                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 201                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 202                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 203                 },
 204         },
 205         {       /* Handle problems with rebooting on Dell 2400's */
 206                 .callback = set_bios_reboot,
 207                 .ident = "Dell PowerEdge 2400",
 208                 .matches = {
 209                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 210                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 211                 },
 212         },
 213         {       /* Handle problems with rebooting on Dell T5400's */
 214                 .callback = set_bios_reboot,
 215                 .ident = "Dell Precision T5400",
 216                 .matches = {
 217                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 218                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 219                 },
 220         },
 221         {       /* Handle problems with rebooting on HP laptops */
 222                 .callback = set_bios_reboot,
 223                 .ident = "HP Compaq Laptop",
 224                 .matches = {
 225                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 226                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 227                 },
 228         },
 229         {       /* Handle problems with rebooting on Dell XPS710 */
 230                 .callback = set_bios_reboot,
 231                 .ident = "Dell XPS710",
 232                 .matches = {
 233                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 234                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 235                 },
 236         },
 237         {       /* Handle problems with rebooting on Dell DXP061 */
 238                 .callback = set_bios_reboot,
 239                 .ident = "Dell DXP061",
 240                 .matches = {
 241                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 242                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 243                 },
 244         },
 245         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 246                 .callback = set_bios_reboot,
 247                 .ident = "Sony VGN-Z540N",
 248                 .matches = {
 249                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 250                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 251                 },
 252         },
 253         {       /* Handle problems with rebooting on CompuLab SBC-FITPC2 */
 254                 .callback = set_bios_reboot,
 255                 .ident = "CompuLab SBC-FITPC2",
 256                 .matches = {
 257                         DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
 258                         DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
 259                 },
 260         },
 261         { }
 262 };
 263
 264 static int __init reboot_init(void)
 265 {
 266         dmi_check_system(reboot_dmi_table);
 267         return 0;
 268 }
 269 core_initcall(reboot_init);
 270
 271 /* The following code and data reboots the machine by switching to real
 272    mode and jumping to the BIOS reset entry point, as if the CPU has
 273    really been reset.  The previous version asked the keyboard
 274    controller to pulse the CPU reset line, which is more thorough, but
 275    doesn't work with at least one type of 486 motherboard.  It is easy
 276    to stop this code working; hence the copious comments. */
 277 static const unsigned long long
 278 real_mode_gdt_entries [3] =
 279 {
 280         0x0000000000000000ULL,  /* Null descriptor */
 281         0x00009b000000ffffULL,  /* 16-bit real-mode 64k code at 0x00000000 */
 282         0x000093000100ffffULL   /* 16-bit real-mode 64k data at 0x00000100 */
 283 };
 284
 285 static const struct desc_ptr
 286 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 287 real_mode_idt = { 0x3ff, 0 };
 288
 289 /* This is 16-bit protected mode code to disable paging and the cache,
 290    switch to real mode and jump to the BIOS reset code.
 291
 292    The instruction that switches to real mode by writing to CR0 must be
 293    followed immediately by a far jump instruction, which set CS to a
 294    valid value for real mode, and flushes the prefetch queue to avoid
 295    running instructions that have already been decoded in protected
 296    mode.
 297
 298    Clears all the flags except ET, especially PG (paging), PE
 299    (protected-mode enable) and TS (task switch for coprocessor state
 300    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 301    NW, to disable the cache on a 486, and invalidates the cache.  This
 302    is more like the state of a 486 after reset.  I don't know if
 303    something else should be done for other chips.
 304
 305    More could be done here to set up the registers as if a CPU reset had
 306    occurred; hopefully real BIOSs don't assume much. */
 307 static const unsigned char real_mode_switch [] =
 308 {
 309         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 310         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 311         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 312         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 313         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 314         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 315         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 316         0x74, 0x02,                             /*    jz    f                */
 317         0x0f, 0x09,                             /*    wbinvd                 */
 318         0x24, 0x10,                             /* f: andb  $0x10,al         */
 319         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 320 };
 321 static const unsigned char jump_to_bios [] =
 322 {
 323         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 324 };
 325
 326 /*
 327  * Switch to real mode and then execute the code
 328  * specified by the code and length parameters.
 329  * We assume that length will aways be less that 100!
 330  */
 331 void machine_real_restart(const unsigned char *code, int length)
 332 {
 333         local_irq_disable();
 334
 335         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 336            routine will recognize as telling it to do a proper reboot.  (Well
 337            that's what this book in front of me says -- it may only apply to
 338            the Phoenix BIOS though, it's not clear).  At the same time,
 339            disable NMIs by setting the top bit in the CMOS address register,
 340            as we're about to do peculiar things to the CPU.  I'm not sure if
 341            `outb_p' is needed instead of just `outb'.  Use it to be on the
 342            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 343          */
 344         spin_lock(&rtc_lock);
 345         CMOS_WRITE(0x00, 0x8f);
 346         spin_unlock(&rtc_lock);
 347
 348         /* Remap the kernel at virtual address zero, as well as offset zero
 349            from the kernel segment.  This assumes the kernel segment starts at
 350            virtual address PAGE_OFFSET. */
 351         memcpy(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
 352                 sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 353
 354         /*
 355          * Use `swapper_pg_dir' as our page directory.
 356          */
 357         load_cr3(swapper_pg_dir);
 358
 359         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 360            this on booting to tell it to "Bypass memory test (also warm
 361            boot)".  This seems like a fairly standard thing that gets set by
 362            REBOOT.COM programs, and the previous reset routine did this
 363            too. */
 364         *((unsigned short *)0x472) = reboot_mode;
 365
 366         /* For the switch to real mode, copy some code to low memory.  It has
 367            to be in the first 64k because it is running in 16-bit mode, and it
 368            has to have the same physical and virtual address, because it turns
 369            off paging.  Copy it near the end of the first page, out of the way
 370            of BIOS variables. */
 371         memcpy((void *)(0x1000 - sizeof(real_mode_switch) - 100),
 372                 real_mode_switch, sizeof (real_mode_switch));
 373         memcpy((void *)(0x1000 - 100), code, length);
 374
 375         /* Set up the IDT for real mode. */
 376         load_idt(&real_mode_idt);
 377
 378         /* Set up a GDT from which we can load segment descriptors for real
 379            mode.  The GDT is not used in real mode; it is just needed here to
 380            prepare the descriptors. */
 381         load_gdt(&real_mode_gdt);
 382
 383         /* Load the data segment registers, and thus the descriptors ready for
 384            real mode.  The base address of each segment is 0x100, 16 times the
 385            selector value being loaded here.  This is so that the segment
 386            registers don't have to be reloaded after switching to real mode:
 387            the values are consistent for real mode operation already. */
 388         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 389                                 "\tmovl %%eax,%%ds\n"
 390                                 "\tmovl %%eax,%%es\n"
 391                                 "\tmovl %%eax,%%fs\n"
 392                                 "\tmovl %%eax,%%gs\n"
 393                                 "\tmovl %%eax,%%ss" : : : "eax");
 394
 395         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 396            and the cache, switches to real mode, and jumps to the BIOS reset
 397            entry point. */
 398         __asm__ __volatile__ ("ljmp $0x0008,%0"
 399                                 :
 400                                 : "i" ((void *)(0x1000 - sizeof (real_mode_switch) - 100)));
 401 }
 402 #ifdef CONFIG_APM_MODULE
 403 EXPORT_SYMBOL(machine_real_restart);
 404 #endif
 405
 406 #endif /* CONFIG_X86_32 */
 407
 408 /*
 409  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 410  */
 411 static int __init set_pci_reboot(const struct dmi_system_id *d)
 412 {
 413         if (reboot_type != BOOT_CF9) {
 414                 reboot_type = BOOT_CF9;
 415                 printk(KERN_INFO "%s series board detected. "
 416                        "Selecting PCI-method for reboots.\n", d->ident);
 417         }
 418         return 0;
 419 }
 420
 421 static struct dmi_system_id __initdata pci_reboot_dmi_table[] = {
 422         {       /* Handle problems with rebooting on Apple MacBook5 */
 423                 .callback = set_pci_reboot,
 424                 .ident = "Apple MacBook5",
 425                 .matches = {
 426                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 427                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 428                 },
 429         },
 430         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 431                 .callback = set_pci_reboot,
 432                 .ident = "Apple MacBookPro5",
 433                 .matches = {
 434                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 435                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 436                 },
 437         },
 438         { }
 439 };
 440
 441 static int __init pci_reboot_init(void)
 442 {
 443         dmi_check_system(pci_reboot_dmi_table);
 444         return 0;
 445 }
 446 core_initcall(pci_reboot_init);
 447
 448 static inline void kb_wait(void)
 449 {
 450         int i;
 451
 452         for (i = 0; i < 0x10000; i++) {
 453                 if ((inb(0x64) & 0x02) == 0)
 454                         break;
 455                 udelay(2);
 456         }
 457 }
 458
 459 static void vmxoff_nmi(int cpu, struct die_args *args)
 460 {
 461         cpu_emergency_vmxoff();
 462 }
 463
 464 /* Use NMIs as IPIs to tell all CPUs to disable virtualization
 465  */
 466 static void emergency_vmx_disable_all(void)
 467 {
 468         /* Just make sure we won't change CPUs while doing this */
 469         local_irq_disable();
 470
 471         /* We need to disable VMX on all CPUs before rebooting, otherwise
 472          * we risk hanging up the machine, because the CPU ignore INIT
 473          * signals when VMX is enabled.
 474          *
 475          * We can't take any locks and we may be on an inconsistent
 476          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 477          * VMX and halt.
 478          *
 479          * For safety, we will avoid running the nmi_shootdown_cpus()
 480          * stuff unnecessarily, but we don't have a way to check
 481          * if other CPUs have VMX enabled. So we will call it only if the
 482          * CPU we are running on has VMX enabled.
 483          *
 484          * We will miss cases where VMX is not enabled on all CPUs. This
 485          * shouldn't do much harm because KVM always enable VMX on all
 486          * CPUs anyway. But we can miss it on the small window where KVM
 487          * is still enabling VMX.
 488          */
 489         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 490                 /* Disable VMX on this CPU.
 491                  */
 492                 cpu_vmxoff();
 493
 494                 /* Halt and disable VMX on the other CPUs */
 495                 nmi_shootdown_cpus(vmxoff_nmi);
 496
 497         }
 498 }
 499
 500
 501 void __attribute__((weak)) mach_reboot_fixups(void)
 502 {
 503 }
 504
 505 static void native_machine_emergency_restart(void)
 506 {
 507         int i;
 508
 509         if (reboot_emergency)
 510                 emergency_vmx_disable_all();
 511
 512         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 513
 514         /* Tell the BIOS if we want cold or warm reboot */
 515         *((unsigned short *)__va(0x472)) = reboot_mode;
 516
 517         for (;;) {
 518                 /* Could also try the reset bit in the Hammer NB */
 519                 switch (reboot_type) {
 520                 case BOOT_KBD:
 521                         mach_reboot_fixups(); /* for board specific fixups */
 522
 523                         for (i = 0; i < 10; i++) {
 524                                 kb_wait();
 525                                 udelay(50);
 526                                 outb(0xfe, 0x64); /* pulse reset low */
 527                                 udelay(50);
 528                         }
 529
 530                 case BOOT_TRIPLE:
 531                         load_idt(&no_idt);
 532                         __asm__ __volatile__("int3");
 533
 534                         reboot_type = BOOT_KBD;
 535                         break;
 536
 537 #ifdef CONFIG_X86_32
 538                 case BOOT_BIOS:
 539                         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 540
 541                         reboot_type = BOOT_KBD;
 542                         break;
 543 #endif
 544
 545                 case BOOT_ACPI:
 546                         acpi_reboot();
 547                         reboot_type = BOOT_KBD;
 548                         break;
 549
 550                 case BOOT_EFI:
 551                         if (efi_enabled)
 552                                 efi.reset_system(reboot_mode ?
 553                                                  EFI_RESET_WARM :
 554                                                  EFI_RESET_COLD,
 555                                                  EFI_SUCCESS, 0, NULL);
 556                         reboot_type = BOOT_KBD;
 557                         break;
 558
 559                 case BOOT_CF9:
 560                         port_cf9_safe = true;
 561                         /* fall through */
 562
 563                 case BOOT_CF9_COND:
 564                         if (port_cf9_safe) {
 565                                 u8 cf9 = inb(0xcf9) & ~6;
 566                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 567                                 udelay(50);
 568                                 outb(cf9|6, 0xcf9); /* Actually do the reset */
 569                                 udelay(50);
 570                         }
 571                         reboot_type = BOOT_KBD;
 572                         break;
 573                 }
 574         }
 575 }
 576
 577 void native_machine_shutdown(void)
 578 {
 579         /* Stop the cpus and apics */
 580 #ifdef CONFIG_SMP
 581
 582         /* The boot cpu is always logical cpu 0 */
 583         int reboot_cpu_id = 0;
 584
 585 #ifdef CONFIG_X86_32
 586         /* See if there has been given a command line override */
 587         if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
 588                 cpu_online(reboot_cpu))
 589                 reboot_cpu_id = reboot_cpu;
 590 #endif
 591
 592         /* Make certain the cpu I'm about to reboot on is online */
 593         if (!cpu_online(reboot_cpu_id))
 594                 reboot_cpu_id = smp_processor_id();
 595
 596         /* Make certain I only run on the appropriate processor */
 597         set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
 598
 599         /* O.K Now that I'm on the appropriate processor,
 600          * stop all of the others.
 601          */
 602         smp_send_stop();
 603 #endif
 604
 605         lapic_shutdown();
 606
 607 #ifdef CONFIG_X86_IO_APIC
 608         disable_IO_APIC();
 609 #endif
 610
 611 #ifdef CONFIG_HPET_TIMER
 612         hpet_disable();
 613 #endif
 614
 615 #ifdef CONFIG_X86_64
 616         pci_iommu_shutdown();
 617 #endif
 618 }
 619
 620 static void __machine_emergency_restart(int emergency)
 621 {
 622         reboot_emergency = emergency;
 623         machine_ops.emergency_restart();
 624 }
 625
 626 static void native_machine_restart(char *__unused)
 627 {
 628         printk("machine restart\n");
 629
 630         if (!reboot_force)
 631                 machine_shutdown();
 632         __machine_emergency_restart(0);
 633 }
 634
 635 static void native_machine_halt(void)
 636 {
 637         /* stop other cpus and apics */
 638         machine_shutdown();
 639
 640         tboot_shutdown(TB_SHUTDOWN_HALT);
 641
 642         /* stop this cpu */
 643         stop_this_cpu(NULL);
 644 }
 645
 646 static void native_machine_power_off(void)
 647 {
 648         if (pm_power_off) {
 649                 if (!reboot_force)
 650                         machine_shutdown();
 651                 pm_power_off();
 652         }
 653         /* a fallback in case there is no PM info available */
 654         tboot_shutdown(TB_SHUTDOWN_HALT);
 655 }
 656
 657 struct machine_ops machine_ops = {
 658         .power_off = native_machine_power_off,
 659         .shutdown = native_machine_shutdown,
 660         .emergency_restart = native_machine_emergency_restart,
 661         .restart = native_machine_restart,
 662         .halt = native_machine_halt,
 663 #ifdef CONFIG_KEXEC
 664         .crash_shutdown = native_machine_crash_shutdown,
 665 #endif
 666 };
 667
 668 void machine_power_off(void)
 669 {
 670         machine_ops.power_off();
 671 }
 672
 673 void machine_shutdown(void)
 674 {
 675         machine_ops.shutdown();
 676 }
 677
 678 void machine_emergency_restart(void)
 679 {
 680         __machine_emergency_restart(1);
 681 }
 682
 683 void machine_restart(char *cmd)
 684 {
 685         machine_ops.restart(cmd);
 686 }
 687
 688 void machine_halt(void)
 689 {
 690         machine_ops.halt();
 691 }
 692
 693 #ifdef CONFIG_KEXEC
 694 void machine_crash_shutdown(struct pt_regs *regs)
 695 {
 696         machine_ops.crash_shutdown(regs);
 697 }
 698 #endif
 699
 700
 701 #if defined(CONFIG_SMP)
 702
 703 /* This keeps a track of which one is crashing cpu. */
 704 static int crashing_cpu;
 705 static nmi_shootdown_cb shootdown_callback;
 706
 707 static atomic_t waiting_for_crash_ipi;
 708
 709 static int crash_nmi_callback(struct notifier_block *self,
 710                         unsigned long val, void *data)
 711 {
 712         int cpu;
 713
 714         if (val != DIE_NMI_IPI)
 715                 return NOTIFY_OK;
 716
 717         cpu = raw_smp_processor_id();
 718
 719         /* Don't do anything if this handler is invoked on crashing cpu.
 720          * Otherwise, system will completely hang. Crashing cpu can get
 721          * an NMI if system was initially booted with nmi_watchdog parameter.
 722          */
 723         if (cpu == crashing_cpu)
 724                 return NOTIFY_STOP;
 725         local_irq_disable();
 726
 727         shootdown_callback(cpu, (struct die_args *)data);
 728
 729         atomic_dec(&waiting_for_crash_ipi);
 730         /* Assume hlt works */
 731         halt();
 732         for (;;)
 733                 cpu_relax();
 734
 735         return 1;
 736 }
 737
 738 static void smp_send_nmi_allbutself(void)
 739 {
 740         apic->send_IPI_allbutself(NMI_VECTOR);
 741 }
 742
 743 static struct notifier_block crash_nmi_nb = {
 744         .notifier_call = crash_nmi_callback,
 745 };
 746
 747 /* Halt all other CPUs, calling the specified function on each of them
 748  *
 749  * This function can be used to halt all other CPUs on crash
 750  * or emergency reboot time. The function passed as parameter
 751  * will be called inside a NMI handler on all CPUs.
 752  */
 753 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 754 {
 755         unsigned long msecs;
 756         local_irq_disable();
 757
 758         /* Make a note of crashing cpu. Will be used in NMI callback.*/
 759         crashing_cpu = safe_smp_processor_id();
 760
 761         shootdown_callback = callback;
 762
 763         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 764         /* Would it be better to replace the trap vector here? */
 765         if (register_die_notifier(&crash_nmi_nb))
 766                 return;         /* return what? */
 767         /* Ensure the new callback function is set before sending
 768          * out the NMI
 769          */
 770         wmb();
 771
 772         smp_send_nmi_allbutself();
 773
 774         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 775         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 776                 mdelay(1);
 777                 msecs--;
 778         }
 779
 780         /* Leave the nmi callback set */
 781 }
 782 #else /* !CONFIG_SMP */
 783 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 784 {
 785         /* No other CPUs to shoot down */
 786 }
 787 #endif