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 <acpi/reboot.h>
   7 #include <asm/io.h>
   8 #include <asm/apic.h>
   9 #include <asm/desc.h>
  10 #include <asm/hpet.h>
  11 #include <asm/pgtable.h>
  12 #include <asm/proto.h>
  13 #include <asm/reboot_fixups.h>
  14 #include <asm/reboot.h>
  15 #include <asm/pci_x86.h>
  16 #include <asm/virtext.h>
  17 #include <asm/cpu.h>
  18
  19 #ifdef CONFIG_X86_32
  20 # include <linux/dmi.h>
  21 # include <linux/ctype.h>
  22 # include <linux/mc146818rtc.h>
  23 #else
  24 # include <asm/iommu.h>
  25 #endif
  26
  27 /*
  28  * Power off function, if any
  29  */
  30 void (*pm_power_off)(void);
  31 EXPORT_SYMBOL(pm_power_off);
  32
  33 static const struct desc_ptr no_idt = {};
  34 static int reboot_mode;
  35 enum reboot_type reboot_type = BOOT_KBD;
  36 int reboot_force;
  37
  38 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
  39 static int reboot_cpu = -1;
  40 #endif
  41
  42 /* This is set if we need to go through the 'emergency' path.
  43  * When machine_emergency_restart() is called, we may be on
  44  * an inconsistent state and won't be able to do a clean cleanup
  45  */
  46 static int reboot_emergency;
  47
  48 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  49 bool port_cf9_safe = false;
  50
  51 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
  52    warm   Don't set the cold reboot flag
  53    cold   Set the cold reboot flag
  54    bios   Reboot by jumping through the BIOS (only for X86_32)
  55    smp    Reboot by executing reset on BSP or other CPU (only for X86_32)
  56    triple Force a triple fault (init)
  57    kbd    Use the keyboard controller. cold reset (default)
  58    acpi   Use the RESET_REG in the FADT
  59    efi    Use efi reset_system runtime service
  60    pci    Use the so-called "PCI reset register", CF9
  61    force  Avoid anything that could hang.
  62  */
  63 static int __init reboot_setup(char *str)
  64 {
  65         for (;;) {
  66                 switch (*str) {
  67                 case 'w':
  68                         reboot_mode = 0x1234;
  69                         break;
  70
  71                 case 'c':
  72                         reboot_mode = 0;
  73                         break;
  74
  75 #ifdef CONFIG_X86_32
  76 #ifdef CONFIG_SMP
  77                 case 's':
  78                         if (isdigit(*(str+1))) {
  79                                 reboot_cpu = (int) (*(str+1) - '0');
  80                                 if (isdigit(*(str+2)))
  81                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
  82                         }
  83                                 /* we will leave sorting out the final value
  84                                    when we are ready to reboot, since we might not
  85                                    have set up boot_cpu_id or smp_num_cpu */
  86                         break;
  87 #endif /* CONFIG_SMP */
  88
  89                 case 'b':
  90 #endif
  91                 case 'a':
  92                 case 'k':
  93                 case 't':
  94                 case 'e':
  95                 case 'p':
  96                         reboot_type = *str;
  97                         break;
  98
  99                 case 'f':
 100                         reboot_force = 1;
 101                         break;
 102                 }
 103
 104                 str = strchr(str, ',');
 105                 if (str)
 106                         str++;
 107                 else
 108                         break;
 109         }
 110         return 1;
 111 }
 112
 113 __setup("reboot=", reboot_setup);
 114
 115
 116 #ifdef CONFIG_X86_32
 117 /*
 118  * Reboot options and system auto-detection code provided by
 119  * Dell Inc. so their systems "just work". :-)
 120  */
 121
 122 /*
 123  * Some machines require the "reboot=b"  commandline option,
 124  * this quirk makes that automatic.
 125  */
 126 static int __init set_bios_reboot(const struct dmi_system_id *d)
 127 {
 128         if (reboot_type != BOOT_BIOS) {
 129                 reboot_type = BOOT_BIOS;
 130                 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
 131         }
 132         return 0;
 133 }
 134
 135 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 136         {       /* Handle problems with rebooting on Dell E520's */
 137                 .callback = set_bios_reboot,
 138                 .ident = "Dell E520",
 139                 .matches = {
 140                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 141                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 142                 },
 143         },
 144         {       /* Handle problems with rebooting on Dell 1300's */
 145                 .callback = set_bios_reboot,
 146                 .ident = "Dell PowerEdge 1300",
 147                 .matches = {
 148                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 149                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 150                 },
 151         },
 152         {       /* Handle problems with rebooting on Dell 300's */
 153                 .callback = set_bios_reboot,
 154                 .ident = "Dell PowerEdge 300",
 155                 .matches = {
 156                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 157                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 158                 },
 159         },
 160         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF*/
 161                 .callback = set_bios_reboot,
 162                 .ident = "Dell OptiPlex 745",
 163                 .matches = {
 164                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 165                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 166                 },
 167         },
 168         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF*/
 169                 .callback = set_bios_reboot,
 170                 .ident = "Dell OptiPlex 745",
 171                 .matches = {
 172                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 173                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 174                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 175                 },
 176         },
 177         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 178                 .callback = set_bios_reboot,
 179                 .ident = "Dell OptiPlex 745",
 180                 .matches = {
 181                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 182                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 183                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 184                 },
 185         },
 186         {   /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 187                 .callback = set_bios_reboot,
 188                 .ident = "Dell OptiPlex 330",
 189                 .matches = {
 190                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 191                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 192                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 193                 },
 194         },
 195         {   /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 196                 .callback = set_bios_reboot,
 197                 .ident = "Dell OptiPlex 360",
 198                 .matches = {
 199                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 200                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 201                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 202                 },
 203         },
 204         {       /* Handle problems with rebooting on Dell 2400's */
 205                 .callback = set_bios_reboot,
 206                 .ident = "Dell PowerEdge 2400",
 207                 .matches = {
 208                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 209                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 210                 },
 211         },
 212         {       /* Handle problems with rebooting on Dell T5400's */
 213                 .callback = set_bios_reboot,
 214                 .ident = "Dell Precision T5400",
 215                 .matches = {
 216                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 217                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 218                 },
 219         },
 220         {       /* Handle problems with rebooting on HP laptops */
 221                 .callback = set_bios_reboot,
 222                 .ident = "HP Compaq Laptop",
 223                 .matches = {
 224                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 225                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 226                 },
 227         },
 228         {       /* Handle problems with rebooting on Dell XPS710 */
 229                 .callback = set_bios_reboot,
 230                 .ident = "Dell XPS710",
 231                 .matches = {
 232                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 233                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 234                 },
 235         },
 236         {       /* Handle problems with rebooting on Dell DXP061 */
 237                 .callback = set_bios_reboot,
 238                 .ident = "Dell DXP061",
 239                 .matches = {
 240                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 241                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 242                 },
 243         },
 244         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 245                 .callback = set_bios_reboot,
 246                 .ident = "Sony VGN-Z540N",
 247                 .matches = {
 248                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 249                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 250                 },
 251         },
 252         {       /* Handle problems with rebooting on CompuLab SBC-FITPC2 */
 253                 .callback = set_bios_reboot,
 254                 .ident = "CompuLab SBC-FITPC2",
 255                 .matches = {
 256                         DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
 257                         DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
 258                 },
 259         },
 260         { }
 261 };
 262
 263 static int __init reboot_init(void)
 264 {
 265         dmi_check_system(reboot_dmi_table);
 266         return 0;
 267 }
 268 core_initcall(reboot_init);
 269
 270 /* The following code and data reboots the machine by switching to real
 271    mode and jumping to the BIOS reset entry point, as if the CPU has
 272    really been reset.  The previous version asked the keyboard
 273    controller to pulse the CPU reset line, which is more thorough, but
 274    doesn't work with at least one type of 486 motherboard.  It is easy
 275    to stop this code working; hence the copious comments. */
 276 static const unsigned long long
 277 real_mode_gdt_entries [3] =
 278 {
 279         0x0000000000000000ULL,  /* Null descriptor */
 280         0x00009b000000ffffULL,  /* 16-bit real-mode 64k code at 0x00000000 */
 281         0x000093000100ffffULL   /* 16-bit real-mode 64k data at 0x00000100 */
 282 };
 283
 284 static const struct desc_ptr
 285 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 286 real_mode_idt = { 0x3ff, 0 };
 287
 288 /* This is 16-bit protected mode code to disable paging and the cache,
 289    switch to real mode and jump to the BIOS reset code.
 290
 291    The instruction that switches to real mode by writing to CR0 must be
 292    followed immediately by a far jump instruction, which set CS to a
 293    valid value for real mode, and flushes the prefetch queue to avoid
 294    running instructions that have already been decoded in protected
 295    mode.
 296
 297    Clears all the flags except ET, especially PG (paging), PE
 298    (protected-mode enable) and TS (task switch for coprocessor state
 299    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 300    NW, to disable the cache on a 486, and invalidates the cache.  This
 301    is more like the state of a 486 after reset.  I don't know if
 302    something else should be done for other chips.
 303
 304    More could be done here to set up the registers as if a CPU reset had
 305    occurred; hopefully real BIOSs don't assume much. */
 306 static const unsigned char real_mode_switch [] =
 307 {
 308         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 309         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 310         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 311         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 312         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 313         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 314         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 315         0x74, 0x02,                             /*    jz    f                */
 316         0x0f, 0x09,                             /*    wbinvd                 */
 317         0x24, 0x10,                             /* f: andb  $0x10,al         */
 318         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 319 };
 320 static const unsigned char jump_to_bios [] =
 321 {
 322         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 323 };
 324
 325 /*
 326  * Switch to real mode and then execute the code
 327  * specified by the code and length parameters.
 328  * We assume that length will aways be less that 100!
 329  */
 330 void machine_real_restart(const unsigned char *code, int length)
 331 {
 332         local_irq_disable();
 333
 334         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 335            routine will recognize as telling it to do a proper reboot.  (Well
 336            that's what this book in front of me says -- it may only apply to
 337            the Phoenix BIOS though, it's not clear).  At the same time,
 338            disable NMIs by setting the top bit in the CMOS address register,
 339            as we're about to do peculiar things to the CPU.  I'm not sure if
 340            `outb_p' is needed instead of just `outb'.  Use it to be on the
 341            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 342          */
 343         spin_lock(&rtc_lock);
 344         CMOS_WRITE(0x00, 0x8f);
 345         spin_unlock(&rtc_lock);
 346
 347         /* Remap the kernel at virtual address zero, as well as offset zero
 348            from the kernel segment.  This assumes the kernel segment starts at
 349            virtual address PAGE_OFFSET. */
 350         memcpy(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
 351                 sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 352
 353         /*
 354          * Use `swapper_pg_dir' as our page directory.
 355          */
 356         load_cr3(swapper_pg_dir);
 357
 358         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 359            this on booting to tell it to "Bypass memory test (also warm
 360            boot)".  This seems like a fairly standard thing that gets set by
 361            REBOOT.COM programs, and the previous reset routine did this
 362            too. */
 363         *((unsigned short *)0x472) = reboot_mode;
 364
 365         /* For the switch to real mode, copy some code to low memory.  It has
 366            to be in the first 64k because it is running in 16-bit mode, and it
 367            has to have the same physical and virtual address, because it turns
 368            off paging.  Copy it near the end of the first page, out of the way
 369            of BIOS variables. */
 370         memcpy((void *)(0x1000 - sizeof(real_mode_switch) - 100),
 371                 real_mode_switch, sizeof (real_mode_switch));
 372         memcpy((void *)(0x1000 - 100), code, length);
 373
 374         /* Set up the IDT for real mode. */
 375         load_idt(&real_mode_idt);
 376
 377         /* Set up a GDT from which we can load segment descriptors for real
 378            mode.  The GDT is not used in real mode; it is just needed here to
 379            prepare the descriptors. */
 380         load_gdt(&real_mode_gdt);
 381
 382         /* Load the data segment registers, and thus the descriptors ready for
 383            real mode.  The base address of each segment is 0x100, 16 times the
 384            selector value being loaded here.  This is so that the segment
 385            registers don't have to be reloaded after switching to real mode:
 386            the values are consistent for real mode operation already. */
 387         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 388                                 "\tmovl %%eax,%%ds\n"
 389                                 "\tmovl %%eax,%%es\n"
 390                                 "\tmovl %%eax,%%fs\n"
 391                                 "\tmovl %%eax,%%gs\n"
 392                                 "\tmovl %%eax,%%ss" : : : "eax");
 393
 394         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 395            and the cache, switches to real mode, and jumps to the BIOS reset
 396            entry point. */
 397         __asm__ __volatile__ ("ljmp $0x0008,%0"
 398                                 :
 399                                 : "i" ((void *)(0x1000 - sizeof (real_mode_switch) - 100)));
 400 }
 401 #ifdef CONFIG_APM_MODULE
 402 EXPORT_SYMBOL(machine_real_restart);
 403 #endif
 404
 405 #endif /* CONFIG_X86_32 */
 406
 407 static inline void kb_wait(void)
 408 {
 409         int i;
 410
 411         for (i = 0; i < 0x10000; i++) {
 412                 if ((inb(0x64) & 0x02) == 0)
 413                         break;
 414                 udelay(2);
 415         }
 416 }
 417
 418 static void vmxoff_nmi(int cpu, struct die_args *args)
 419 {
 420         cpu_emergency_vmxoff();
 421 }
 422
 423 /* Use NMIs as IPIs to tell all CPUs to disable virtualization
 424  */
 425 static void emergency_vmx_disable_all(void)
 426 {
 427         /* Just make sure we won't change CPUs while doing this */
 428         local_irq_disable();
 429
 430         /* We need to disable VMX on all CPUs before rebooting, otherwise
 431          * we risk hanging up the machine, because the CPU ignore INIT
 432          * signals when VMX is enabled.
 433          *
 434          * We can't take any locks and we may be on an inconsistent
 435          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 436          * VMX and halt.
 437          *
 438          * For safety, we will avoid running the nmi_shootdown_cpus()
 439          * stuff unnecessarily, but we don't have a way to check
 440          * if other CPUs have VMX enabled. So we will call it only if the
 441          * CPU we are running on has VMX enabled.
 442          *
 443          * We will miss cases where VMX is not enabled on all CPUs. This
 444          * shouldn't do much harm because KVM always enable VMX on all
 445          * CPUs anyway. But we can miss it on the small window where KVM
 446          * is still enabling VMX.
 447          */
 448         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 449                 /* Disable VMX on this CPU.
 450                  */
 451                 cpu_vmxoff();
 452
 453                 /* Halt and disable VMX on the other CPUs */
 454                 nmi_shootdown_cpus(vmxoff_nmi);
 455
 456         }
 457 }
 458
 459
 460 void __attribute__((weak)) mach_reboot_fixups(void)
 461 {
 462 }
 463
 464 static void native_machine_emergency_restart(void)
 465 {
 466         int i;
 467
 468         if (reboot_emergency)
 469                 emergency_vmx_disable_all();
 470
 471         /* Tell the BIOS if we want cold or warm reboot */
 472         *((unsigned short *)__va(0x472)) = reboot_mode;
 473
 474         for (;;) {
 475                 /* Could also try the reset bit in the Hammer NB */
 476                 switch (reboot_type) {
 477                 case BOOT_KBD:
 478                         mach_reboot_fixups(); /* for board specific fixups */
 479
 480                         for (i = 0; i < 10; i++) {
 481                                 kb_wait();
 482                                 udelay(50);
 483                                 outb(0xfe, 0x64); /* pulse reset low */
 484                                 udelay(50);
 485                         }
 486
 487                 case BOOT_TRIPLE:
 488                         load_idt(&no_idt);
 489                         __asm__ __volatile__("int3");
 490
 491                         reboot_type = BOOT_KBD;
 492                         break;
 493
 494 #ifdef CONFIG_X86_32
 495                 case BOOT_BIOS:
 496                         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 497
 498                         reboot_type = BOOT_KBD;
 499                         break;
 500 #endif
 501
 502                 case BOOT_ACPI:
 503                         acpi_reboot();
 504                         reboot_type = BOOT_KBD;
 505                         break;
 506
 507                 case BOOT_EFI:
 508                         if (efi_enabled)
 509                                 efi.reset_system(reboot_mode ?
 510                                                  EFI_RESET_WARM :
 511                                                  EFI_RESET_COLD,
 512                                                  EFI_SUCCESS, 0, NULL);
 513                         reboot_type = BOOT_KBD;
 514                         break;
 515
 516                 case BOOT_CF9:
 517                         port_cf9_safe = true;
 518                         /* fall through */
 519
 520                 case BOOT_CF9_COND:
 521                         if (port_cf9_safe) {
 522                                 u8 cf9 = inb(0xcf9) & ~6;
 523                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 524                                 udelay(50);
 525                                 outb(cf9|6, 0xcf9); /* Actually do the reset */
 526                                 udelay(50);
 527                         }
 528                         reboot_type = BOOT_KBD;
 529                         break;
 530                 }
 531         }
 532 }
 533
 534 void native_machine_shutdown(void)
 535 {
 536         /* Stop the cpus and apics */
 537 #ifdef CONFIG_SMP
 538
 539         /* The boot cpu is always logical cpu 0 */
 540         int reboot_cpu_id = 0;
 541
 542 #ifdef CONFIG_X86_32
 543         /* See if there has been given a command line override */
 544         if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
 545                 cpu_online(reboot_cpu))
 546                 reboot_cpu_id = reboot_cpu;
 547 #endif
 548
 549         /* Make certain the cpu I'm about to reboot on is online */
 550         if (!cpu_online(reboot_cpu_id))
 551                 reboot_cpu_id = smp_processor_id();
 552
 553         /* Make certain I only run on the appropriate processor */
 554         set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
 555
 556         /* O.K Now that I'm on the appropriate processor,
 557          * stop all of the others.
 558          */
 559         smp_send_stop();
 560 #endif
 561
 562         lapic_shutdown();
 563
 564 #ifdef CONFIG_X86_IO_APIC
 565         disable_IO_APIC();
 566 #endif
 567
 568 #ifdef CONFIG_HPET_TIMER
 569         hpet_disable();
 570 #endif
 571
 572 #ifdef CONFIG_X86_64
 573         pci_iommu_shutdown();
 574 #endif
 575 }
 576
 577 static void __machine_emergency_restart(int emergency)
 578 {
 579         reboot_emergency = emergency;
 580         machine_ops.emergency_restart();
 581 }
 582
 583 static void native_machine_restart(char *__unused)
 584 {
 585         printk("machine restart\n");
 586
 587         if (!reboot_force)
 588                 machine_shutdown();
 589         __machine_emergency_restart(0);
 590 }
 591
 592 static void native_machine_halt(void)
 593 {
 594         /* stop other cpus and apics */
 595         machine_shutdown();
 596
 597         /* stop this cpu */
 598         stop_this_cpu(NULL);
 599 }
 600
 601 static void native_machine_power_off(void)
 602 {
 603         if (pm_power_off) {
 604                 if (!reboot_force)
 605                         machine_shutdown();
 606                 pm_power_off();
 607         }
 608 }
 609
 610 struct machine_ops machine_ops = {
 611         .power_off = native_machine_power_off,
 612         .shutdown = native_machine_shutdown,
 613         .emergency_restart = native_machine_emergency_restart,
 614         .restart = native_machine_restart,
 615         .halt = native_machine_halt,
 616 #ifdef CONFIG_KEXEC
 617         .crash_shutdown = native_machine_crash_shutdown,
 618 #endif
 619 };
 620
 621 void machine_power_off(void)
 622 {
 623         machine_ops.power_off();
 624 }
 625
 626 void machine_shutdown(void)
 627 {
 628         machine_ops.shutdown();
 629 }
 630
 631 void machine_emergency_restart(void)
 632 {
 633         __machine_emergency_restart(1);
 634 }
 635
 636 void machine_restart(char *cmd)
 637 {
 638         machine_ops.restart(cmd);
 639 }
 640
 641 void machine_halt(void)
 642 {
 643         machine_ops.halt();
 644 }
 645
 646 #ifdef CONFIG_KEXEC
 647 void machine_crash_shutdown(struct pt_regs *regs)
 648 {
 649         machine_ops.crash_shutdown(regs);
 650 }
 651 #endif
 652
 653
 654 #if defined(CONFIG_SMP)
 655
 656 /* This keeps a track of which one is crashing cpu. */
 657 static int crashing_cpu;
 658 static nmi_shootdown_cb shootdown_callback;
 659
 660 static atomic_t waiting_for_crash_ipi;
 661
 662 static int crash_nmi_callback(struct notifier_block *self,
 663                         unsigned long val, void *data)
 664 {
 665         int cpu;
 666
 667         if (val != DIE_NMI_IPI)
 668                 return NOTIFY_OK;
 669
 670         cpu = raw_smp_processor_id();
 671
 672         /* Don't do anything if this handler is invoked on crashing cpu.
 673          * Otherwise, system will completely hang. Crashing cpu can get
 674          * an NMI if system was initially booted with nmi_watchdog parameter.
 675          */
 676         if (cpu == crashing_cpu)
 677                 return NOTIFY_STOP;
 678         local_irq_disable();
 679
 680         shootdown_callback(cpu, (struct die_args *)data);
 681
 682         atomic_dec(&waiting_for_crash_ipi);
 683         /* Assume hlt works */
 684         halt();
 685         for (;;)
 686                 cpu_relax();
 687
 688         return 1;
 689 }
 690
 691 static void smp_send_nmi_allbutself(void)
 692 {
 693         apic->send_IPI_allbutself(NMI_VECTOR);
 694 }
 695
 696 static struct notifier_block crash_nmi_nb = {
 697         .notifier_call = crash_nmi_callback,
 698 };
 699
 700 /* Halt all other CPUs, calling the specified function on each of them
 701  *
 702  * This function can be used to halt all other CPUs on crash
 703  * or emergency reboot time. The function passed as parameter
 704  * will be called inside a NMI handler on all CPUs.
 705  */
 706 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 707 {
 708         unsigned long msecs;
 709         local_irq_disable();
 710
 711         /* Make a note of crashing cpu. Will be used in NMI callback.*/
 712         crashing_cpu = safe_smp_processor_id();
 713
 714         shootdown_callback = callback;
 715
 716         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 717         /* Would it be better to replace the trap vector here? */
 718         if (register_die_notifier(&crash_nmi_nb))
 719                 return;         /* return what? */
 720         /* Ensure the new callback function is set before sending
 721          * out the NMI
 722          */
 723         wmb();
 724
 725         smp_send_nmi_allbutself();
 726
 727         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 728         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 729                 mdelay(1);
 730                 msecs--;
 731         }
 732
 733         /* Leave the nmi callback set */
 734 }
 735 #else /* !CONFIG_SMP */
 736 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 737 {
 738         /* No other CPUs to shoot down */
 739 }
 740 #endif