linux/arch/x86/kernel/reboot.c
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   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 */
  35void (*pm_power_off)(void);
  36EXPORT_SYMBOL(pm_power_off);
  37
  38static const struct desc_ptr no_idt = {};
  39static int reboot_mode;
  40enum reboot_type reboot_type = BOOT_ACPI;
  41int 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 */
  50static int reboot_default = 1;
  51
  52#ifdef CONFIG_SMP
  53static 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 */
  61static int reboot_emergency;
  62
  63/* This is set by the PCI code if either type 1 or type 2 PCI is detected */
  64bool 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 */
  79static 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 */
 148static 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
 158void __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
 198EXPORT_SYMBOL(machine_real_restart);
 199#endif
 200
 201/*
 202 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 203 */
 204static 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
 214static 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 */
 227static 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 ASUS P4S800 */
 362                .callback = set_bios_reboot,
 363                .ident = "ASUS P4S800",
 364                .matches = {
 365                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 366                        DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 367                },
 368        },
 369
 370        {       /* Handle reboot issue on Acer Aspire one */
 371                .callback = set_kbd_reboot,
 372                .ident = "Acer Aspire One A110",
 373                .matches = {
 374                        DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 375                        DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 376                },
 377        },
 378        {       /* Handle problems with rebooting on Apple MacBook5 */
 379                .callback = set_pci_reboot,
 380                .ident = "Apple MacBook5",
 381                .matches = {
 382                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 383                        DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 384                },
 385        },
 386        {       /* Handle problems with rebooting on Apple MacBookPro5 */
 387                .callback = set_pci_reboot,
 388                .ident = "Apple MacBookPro5",
 389                .matches = {
 390                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 391                        DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 392                },
 393        },
 394        {       /* Handle problems with rebooting on Apple Macmini3,1 */
 395                .callback = set_pci_reboot,
 396                .ident = "Apple Macmini3,1",
 397                .matches = {
 398                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 399                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 400                },
 401        },
 402        {       /* Handle problems with rebooting on the iMac9,1. */
 403                .callback = set_pci_reboot,
 404                .ident = "Apple iMac9,1",
 405                .matches = {
 406                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 407                        DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 408                },
 409        },
 410        {       /* Handle problems with rebooting on the Latitude E6320. */
 411                .callback = set_pci_reboot,
 412                .ident = "Dell Latitude E6320",
 413                .matches = {
 414                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 415                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 416                },
 417        },
 418        {       /* Handle problems with rebooting on the Latitude E5420. */
 419                .callback = set_pci_reboot,
 420                .ident = "Dell Latitude E5420",
 421                .matches = {
 422                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 423                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 424                },
 425        },
 426        {       /* Handle problems with rebooting on the Latitude E6420. */
 427                .callback = set_pci_reboot,
 428                .ident = "Dell Latitude E6420",
 429                .matches = {
 430                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 431                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 432                },
 433        },
 434        {       /* Handle problems with rebooting on the OptiPlex 990. */
 435                .callback = set_pci_reboot,
 436                .ident = "Dell OptiPlex 990",
 437                .matches = {
 438                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 439                        DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 440                },
 441        },
 442        {       /* Handle problems with rebooting on the Precision M6600. */
 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, "Precision M6600"),
 448                },
 449        },
 450        { }
 451};
 452
 453static int __init reboot_init(void)
 454{
 455        /*
 456         * Only do the DMI check if reboot_type hasn't been overridden
 457         * on the command line
 458         */
 459        if (reboot_default)
 460                dmi_check_system(reboot_dmi_table);
 461        return 0;
 462}
 463core_initcall(reboot_init);
 464
 465static inline void kb_wait(void)
 466{
 467        int i;
 468
 469        for (i = 0; i < 0x10000; i++) {
 470                if ((inb(0x64) & 0x02) == 0)
 471                        break;
 472                udelay(2);
 473        }
 474}
 475
 476static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 477{
 478        cpu_emergency_vmxoff();
 479}
 480
 481/* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 482static void emergency_vmx_disable_all(void)
 483{
 484        /* Just make sure we won't change CPUs while doing this */
 485        local_irq_disable();
 486
 487        /*
 488         * We need to disable VMX on all CPUs before rebooting, otherwise
 489         * we risk hanging up the machine, because the CPU ignore INIT
 490         * signals when VMX is enabled.
 491         *
 492         * We can't take any locks and we may be on an inconsistent
 493         * state, so we use NMIs as IPIs to tell the other CPUs to disable
 494         * VMX and halt.
 495         *
 496         * For safety, we will avoid running the nmi_shootdown_cpus()
 497         * stuff unnecessarily, but we don't have a way to check
 498         * if other CPUs have VMX enabled. So we will call it only if the
 499         * CPU we are running on has VMX enabled.
 500         *
 501         * We will miss cases where VMX is not enabled on all CPUs. This
 502         * shouldn't do much harm because KVM always enable VMX on all
 503         * CPUs anyway. But we can miss it on the small window where KVM
 504         * is still enabling VMX.
 505         */
 506        if (cpu_has_vmx() && cpu_vmx_enabled()) {
 507                /* Disable VMX on this CPU. */
 508                cpu_vmxoff();
 509
 510                /* Halt and disable VMX on the other CPUs */
 511                nmi_shootdown_cpus(vmxoff_nmi);
 512
 513        }
 514}
 515
 516
 517void __attribute__((weak)) mach_reboot_fixups(void)
 518{
 519}
 520
 521/*
 522 * Windows compatible x86 hardware expects the following on reboot:
 523 *
 524 * 1) If the FADT has the ACPI reboot register flag set, try it
 525 * 2) If still alive, write to the keyboard controller
 526 * 3) If still alive, write to the ACPI reboot register again
 527 * 4) If still alive, write to the keyboard controller again
 528 *
 529 * If the machine is still alive at this stage, it gives up. We default to
 530 * following the same pattern, except that if we're still alive after (4) we'll
 531 * try to force a triple fault and then cycle between hitting the keyboard
 532 * controller and doing that
 533 */
 534static void native_machine_emergency_restart(void)
 535{
 536        int i;
 537        int attempt = 0;
 538        int orig_reboot_type = reboot_type;
 539
 540        if (reboot_emergency)
 541                emergency_vmx_disable_all();
 542
 543        tboot_shutdown(TB_SHUTDOWN_REBOOT);
 544
 545        /* Tell the BIOS if we want cold or warm reboot */
 546        *((unsigned short *)__va(0x472)) = reboot_mode;
 547
 548        for (;;) {
 549                /* Could also try the reset bit in the Hammer NB */
 550                switch (reboot_type) {
 551                case BOOT_KBD:
 552                        mach_reboot_fixups(); /* For board specific fixups */
 553
 554                        for (i = 0; i < 10; i++) {
 555                                kb_wait();
 556                                udelay(50);
 557                                outb(0xfe, 0x64); /* Pulse reset low */
 558                                udelay(50);
 559                        }
 560                        if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 561                                attempt = 1;
 562                                reboot_type = BOOT_ACPI;
 563                        } else {
 564                                reboot_type = BOOT_TRIPLE;
 565                        }
 566                        break;
 567
 568                case BOOT_TRIPLE:
 569                        load_idt(&no_idt);
 570                        __asm__ __volatile__("int3");
 571
 572                        reboot_type = BOOT_KBD;
 573                        break;
 574
 575                case BOOT_BIOS:
 576                        machine_real_restart(MRR_BIOS);
 577
 578                        reboot_type = BOOT_KBD;
 579                        break;
 580
 581                case BOOT_ACPI:
 582                        acpi_reboot();
 583                        reboot_type = BOOT_KBD;
 584                        break;
 585
 586                case BOOT_EFI:
 587                        if (efi_enabled)
 588                                efi.reset_system(reboot_mode ?
 589                                                 EFI_RESET_WARM :
 590                                                 EFI_RESET_COLD,
 591                                                 EFI_SUCCESS, 0, NULL);
 592                        reboot_type = BOOT_KBD;
 593                        break;
 594
 595                case BOOT_CF9:
 596                        port_cf9_safe = true;
 597                        /* Fall through */
 598
 599                case BOOT_CF9_COND:
 600                        if (port_cf9_safe) {
 601                                u8 cf9 = inb(0xcf9) & ~6;
 602                                outb(cf9|2, 0xcf9); /* Request hard reset */
 603                                udelay(50);
 604                                outb(cf9|6, 0xcf9); /* Actually do the reset */
 605                                udelay(50);
 606                        }
 607                        reboot_type = BOOT_KBD;
 608                        break;
 609                }
 610        }
 611}
 612
 613void native_machine_shutdown(void)
 614{
 615        /* Stop the cpus and apics */
 616#ifdef CONFIG_SMP
 617
 618        /* The boot cpu is always logical cpu 0 */
 619        int reboot_cpu_id = 0;
 620
 621        /* See if there has been given a command line override */
 622        if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
 623                cpu_online(reboot_cpu))
 624                reboot_cpu_id = reboot_cpu;
 625
 626        /* Make certain the cpu I'm about to reboot on is online */
 627        if (!cpu_online(reboot_cpu_id))
 628                reboot_cpu_id = smp_processor_id();
 629
 630        /* Make certain I only run on the appropriate processor */
 631        set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
 632
 633        /*
 634         * O.K Now that I'm on the appropriate processor, stop all of the
 635         * others. Also disable the local irq to not receive the per-cpu
 636         * timer interrupt which may trigger scheduler's load balance.
 637         */
 638        local_irq_disable();
 639        stop_other_cpus();
 640#endif
 641
 642        lapic_shutdown();
 643
 644#ifdef CONFIG_X86_IO_APIC
 645        disable_IO_APIC();
 646#endif
 647
 648#ifdef CONFIG_HPET_TIMER
 649        hpet_disable();
 650#endif
 651
 652#ifdef CONFIG_X86_64
 653        x86_platform.iommu_shutdown();
 654#endif
 655}
 656
 657static void __machine_emergency_restart(int emergency)
 658{
 659        reboot_emergency = emergency;
 660        machine_ops.emergency_restart();
 661}
 662
 663static void native_machine_restart(char *__unused)
 664{
 665        pr_notice("machine restart\n");
 666
 667        if (!reboot_force)
 668                machine_shutdown();
 669        __machine_emergency_restart(0);
 670}
 671
 672static void native_machine_halt(void)
 673{
 674        /* Stop other cpus and apics */
 675        machine_shutdown();
 676
 677        tboot_shutdown(TB_SHUTDOWN_HALT);
 678
 679        stop_this_cpu(NULL);
 680}
 681
 682static void native_machine_power_off(void)
 683{
 684        if (pm_power_off) {
 685                if (!reboot_force)
 686                        machine_shutdown();
 687                pm_power_off();
 688        }
 689        /* A fallback in case there is no PM info available */
 690        tboot_shutdown(TB_SHUTDOWN_HALT);
 691}
 692
 693struct machine_ops machine_ops = {
 694        .power_off = native_machine_power_off,
 695        .shutdown = native_machine_shutdown,
 696        .emergency_restart = native_machine_emergency_restart,
 697        .restart = native_machine_restart,
 698        .halt = native_machine_halt,
 699#ifdef CONFIG_KEXEC
 700        .crash_shutdown = native_machine_crash_shutdown,
 701#endif
 702};
 703
 704void machine_power_off(void)
 705{
 706        machine_ops.power_off();
 707}
 708
 709void machine_shutdown(void)
 710{
 711        machine_ops.shutdown();
 712}
 713
 714void machine_emergency_restart(void)
 715{
 716        __machine_emergency_restart(1);
 717}
 718
 719void machine_restart(char *cmd)
 720{
 721        machine_ops.restart(cmd);
 722}
 723
 724void machine_halt(void)
 725{
 726        machine_ops.halt();
 727}
 728
 729#ifdef CONFIG_KEXEC
 730void machine_crash_shutdown(struct pt_regs *regs)
 731{
 732        machine_ops.crash_shutdown(regs);
 733}
 734#endif
 735
 736
 737#if defined(CONFIG_SMP)
 738
 739/* This keeps a track of which one is crashing cpu. */
 740static int crashing_cpu;
 741static nmi_shootdown_cb shootdown_callback;
 742
 743static atomic_t waiting_for_crash_ipi;
 744
 745static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 746{
 747        int cpu;
 748
 749        cpu = raw_smp_processor_id();
 750
 751        /*
 752         * Don't do anything if this handler is invoked on crashing cpu.
 753         * Otherwise, system will completely hang. Crashing cpu can get
 754         * an NMI if system was initially booted with nmi_watchdog parameter.
 755         */
 756        if (cpu == crashing_cpu)
 757                return NMI_HANDLED;
 758        local_irq_disable();
 759
 760        shootdown_callback(cpu, regs);
 761
 762        atomic_dec(&waiting_for_crash_ipi);
 763        /* Assume hlt works */
 764        halt();
 765        for (;;)
 766                cpu_relax();
 767
 768        return NMI_HANDLED;
 769}
 770
 771static void smp_send_nmi_allbutself(void)
 772{
 773        apic->send_IPI_allbutself(NMI_VECTOR);
 774}
 775
 776/*
 777 * Halt all other CPUs, calling the specified function on each of them
 778 *
 779 * This function can be used to halt all other CPUs on crash
 780 * or emergency reboot time. The function passed as parameter
 781 * will be called inside a NMI handler on all CPUs.
 782 */
 783void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 784{
 785        unsigned long msecs;
 786        local_irq_disable();
 787
 788        /* Make a note of crashing cpu. Will be used in NMI callback. */
 789        crashing_cpu = safe_smp_processor_id();
 790
 791        shootdown_callback = callback;
 792
 793        atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 794        /* Would it be better to replace the trap vector here? */
 795        if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 796                                 NMI_FLAG_FIRST, "crash"))
 797                return;         /* Return what? */
 798        /*
 799         * Ensure the new callback function is set before sending
 800         * out the NMI
 801         */
 802        wmb();
 803
 804        smp_send_nmi_allbutself();
 805
 806        msecs = 1000; /* Wait at most a second for the other cpus to stop */
 807        while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 808                mdelay(1);
 809                msecs--;
 810        }
 811
 812        /* Leave the nmi callback set */
 813}
 814#else /* !CONFIG_SMP */
 815void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 816{
 817        /* No other CPUs to shoot down */
 818}
 819#endif
 820
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