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 CompuLab SBC-FITPC2 */
 362                .callback = set_bios_reboot,
 363                .ident = "CompuLab SBC-FITPC2",
 364                .matches = {
 365                        DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
 366                        DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
 367                },
 368        },
 369        {       /* Handle problems with rebooting on ASUS P4S800 */
 370                .callback = set_bios_reboot,
 371                .ident = "ASUS P4S800",
 372                .matches = {
 373                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 374                        DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 375                },
 376        },
 377
 378        {       /* Handle reboot issue on Acer Aspire one */
 379                .callback = set_kbd_reboot,
 380                .ident = "Acer Aspire One A110",
 381                .matches = {
 382                        DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 383                        DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 384                },
 385        },
 386        {       /* Handle problems with rebooting on Apple MacBook5 */
 387                .callback = set_pci_reboot,
 388                .ident = "Apple MacBook5",
 389                .matches = {
 390                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 391                        DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 392                },
 393        },
 394        {       /* Handle problems with rebooting on Apple MacBookPro5 */
 395                .callback = set_pci_reboot,
 396                .ident = "Apple MacBookPro5",
 397                .matches = {
 398                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 399                        DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 400                },
 401        },
 402        {       /* Handle problems with rebooting on Apple Macmini3,1 */
 403                .callback = set_pci_reboot,
 404                .ident = "Apple Macmini3,1",
 405                .matches = {
 406                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 407                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 408                },
 409        },
 410        {       /* Handle problems with rebooting on the iMac9,1. */
 411                .callback = set_pci_reboot,
 412                .ident = "Apple iMac9,1",
 413                .matches = {
 414                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 415                        DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 416                },
 417        },
 418        {       /* Handle problems with rebooting on the Latitude E6320. */
 419                .callback = set_pci_reboot,
 420                .ident = "Dell Latitude E6320",
 421                .matches = {
 422                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 423                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 424                },
 425        },
 426        {       /* Handle problems with rebooting on the Latitude E5420. */
 427                .callback = set_pci_reboot,
 428                .ident = "Dell Latitude E5420",
 429                .matches = {
 430                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 431                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 432                },
 433        },
 434        {       /* Handle problems with rebooting on the Latitude E6420. */
 435                .callback = set_pci_reboot,
 436                .ident = "Dell Latitude E6420",
 437                .matches = {
 438                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 439                        DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 440                },
 441        },
 442        {       /* Handle problems with rebooting on the OptiPlex 990. */
 443                .callback = set_pci_reboot,
 444                .ident = "Dell OptiPlex 990",
 445                .matches = {
 446                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 447                        DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 448                },
 449        },
 450        {       /* Handle problems with rebooting on the Precision M6600. */
 451                .callback = set_pci_reboot,
 452                .ident = "Dell OptiPlex 990",
 453                .matches = {
 454                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 455                        DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 456                },
 457        },
 458        { }
 459};
 460
 461static int __init reboot_init(void)
 462{
 463        /*
 464         * Only do the DMI check if reboot_type hasn't been overridden
 465         * on the command line
 466         */
 467        if (reboot_default)
 468                dmi_check_system(reboot_dmi_table);
 469        return 0;
 470}
 471core_initcall(reboot_init);
 472
 473static inline void kb_wait(void)
 474{
 475        int i;
 476
 477        for (i = 0; i < 0x10000; i++) {
 478                if ((inb(0x64) & 0x02) == 0)
 479                        break;
 480                udelay(2);
 481        }
 482}
 483
 484static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 485{
 486        cpu_emergency_vmxoff();
 487}
 488
 489/* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 490static void emergency_vmx_disable_all(void)
 491{
 492        /* Just make sure we won't change CPUs while doing this */
 493        local_irq_disable();
 494
 495        /*
 496         * We need to disable VMX on all CPUs before rebooting, otherwise
 497         * we risk hanging up the machine, because the CPU ignore INIT
 498         * signals when VMX is enabled.
 499         *
 500         * We can't take any locks and we may be on an inconsistent
 501         * state, so we use NMIs as IPIs to tell the other CPUs to disable
 502         * VMX and halt.
 503         *
 504         * For safety, we will avoid running the nmi_shootdown_cpus()
 505         * stuff unnecessarily, but we don't have a way to check
 506         * if other CPUs have VMX enabled. So we will call it only if the
 507         * CPU we are running on has VMX enabled.
 508         *
 509         * We will miss cases where VMX is not enabled on all CPUs. This
 510         * shouldn't do much harm because KVM always enable VMX on all
 511         * CPUs anyway. But we can miss it on the small window where KVM
 512         * is still enabling VMX.
 513         */
 514        if (cpu_has_vmx() && cpu_vmx_enabled()) {
 515                /* Disable VMX on this CPU. */
 516                cpu_vmxoff();
 517
 518                /* Halt and disable VMX on the other CPUs */
 519                nmi_shootdown_cpus(vmxoff_nmi);
 520
 521        }
 522}
 523
 524
 525void __attribute__((weak)) mach_reboot_fixups(void)
 526{
 527}
 528
 529/*
 530 * Windows compatible x86 hardware expects the following on reboot:
 531 *
 532 * 1) If the FADT has the ACPI reboot register flag set, try it
 533 * 2) If still alive, write to the keyboard controller
 534 * 3) If still alive, write to the ACPI reboot register again
 535 * 4) If still alive, write to the keyboard controller again
 536 *
 537 * If the machine is still alive at this stage, it gives up. We default to
 538 * following the same pattern, except that if we're still alive after (4) we'll
 539 * try to force a triple fault and then cycle between hitting the keyboard
 540 * controller and doing that
 541 */
 542static void native_machine_emergency_restart(void)
 543{
 544        int i;
 545        int attempt = 0;
 546        int orig_reboot_type = reboot_type;
 547
 548        if (reboot_emergency)
 549                emergency_vmx_disable_all();
 550
 551        tboot_shutdown(TB_SHUTDOWN_REBOOT);
 552
 553        /* Tell the BIOS if we want cold or warm reboot */
 554        *((unsigned short *)__va(0x472)) = reboot_mode;
 555
 556        for (;;) {
 557                /* Could also try the reset bit in the Hammer NB */
 558                switch (reboot_type) {
 559                case BOOT_KBD:
 560                        mach_reboot_fixups(); /* For board specific fixups */
 561
 562                        for (i = 0; i < 10; i++) {
 563                                kb_wait();
 564                                udelay(50);
 565                                outb(0xfe, 0x64); /* Pulse reset low */
 566                                udelay(50);
 567                        }
 568                        if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 569                                attempt = 1;
 570                                reboot_type = BOOT_ACPI;
 571                        } else {
 572                                reboot_type = BOOT_TRIPLE;
 573                        }
 574                        break;
 575
 576                case BOOT_TRIPLE:
 577                        load_idt(&no_idt);
 578                        __asm__ __volatile__("int3");
 579
 580                        reboot_type = BOOT_KBD;
 581                        break;
 582
 583                case BOOT_BIOS:
 584                        machine_real_restart(MRR_BIOS);
 585
 586                        reboot_type = BOOT_KBD;
 587                        break;
 588
 589                case BOOT_ACPI:
 590                        acpi_reboot();
 591                        reboot_type = BOOT_KBD;
 592                        break;
 593
 594                case BOOT_EFI:
 595                        if (efi_enabled)
 596                                efi.reset_system(reboot_mode ?
 597                                                 EFI_RESET_WARM :
 598                                                 EFI_RESET_COLD,
 599                                                 EFI_SUCCESS, 0, NULL);
 600                        reboot_type = BOOT_KBD;
 601                        break;
 602
 603                case BOOT_CF9:
 604                        port_cf9_safe = true;
 605                        /* Fall through */
 606
 607                case BOOT_CF9_COND:
 608                        if (port_cf9_safe) {
 609                                u8 cf9 = inb(0xcf9) & ~6;
 610                                outb(cf9|2, 0xcf9); /* Request hard reset */
 611                                udelay(50);
 612                                outb(cf9|6, 0xcf9); /* Actually do the reset */
 613                                udelay(50);
 614                        }
 615                        reboot_type = BOOT_KBD;
 616                        break;
 617                }
 618        }
 619}
 620
 621void native_machine_shutdown(void)
 622{
 623        /* Stop the cpus and apics */
 624#ifdef CONFIG_SMP
 625
 626        /* The boot cpu is always logical cpu 0 */
 627        int reboot_cpu_id = 0;
 628
 629        /* See if there has been given a command line override */
 630        if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
 631                cpu_online(reboot_cpu))
 632                reboot_cpu_id = reboot_cpu;
 633
 634        /* Make certain the cpu I'm about to reboot on is online */
 635        if (!cpu_online(reboot_cpu_id))
 636                reboot_cpu_id = smp_processor_id();
 637
 638        /* Make certain I only run on the appropriate processor */
 639        set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
 640
 641        /*
 642         * O.K Now that I'm on the appropriate processor, stop all of the
 643         * others. Also disable the local irq to not receive the per-cpu
 644         * timer interrupt which may trigger scheduler's load balance.
 645         */
 646        local_irq_disable();
 647        stop_other_cpus();
 648#endif
 649
 650        lapic_shutdown();
 651
 652#ifdef CONFIG_X86_IO_APIC
 653        disable_IO_APIC();
 654#endif
 655
 656#ifdef CONFIG_HPET_TIMER
 657        hpet_disable();
 658#endif
 659
 660#ifdef CONFIG_X86_64
 661        x86_platform.iommu_shutdown();
 662#endif
 663}
 664
 665static void __machine_emergency_restart(int emergency)
 666{
 667        reboot_emergency = emergency;
 668        machine_ops.emergency_restart();
 669}
 670
 671static void native_machine_restart(char *__unused)
 672{
 673        pr_notice("machine restart\n");
 674
 675        if (!reboot_force)
 676                machine_shutdown();
 677        __machine_emergency_restart(0);
 678}
 679
 680static void native_machine_halt(void)
 681{
 682        /* Stop other cpus and apics */
 683        machine_shutdown();
 684
 685        tboot_shutdown(TB_SHUTDOWN_HALT);
 686
 687        stop_this_cpu(NULL);
 688}
 689
 690static void native_machine_power_off(void)
 691{
 692        if (pm_power_off) {
 693                if (!reboot_force)
 694                        machine_shutdown();
 695                pm_power_off();
 696        }
 697        /* A fallback in case there is no PM info available */
 698        tboot_shutdown(TB_SHUTDOWN_HALT);
 699}
 700
 701struct machine_ops machine_ops = {
 702        .power_off = native_machine_power_off,
 703        .shutdown = native_machine_shutdown,
 704        .emergency_restart = native_machine_emergency_restart,
 705        .restart = native_machine_restart,
 706        .halt = native_machine_halt,
 707#ifdef CONFIG_KEXEC
 708        .crash_shutdown = native_machine_crash_shutdown,
 709#endif
 710};
 711
 712void machine_power_off(void)
 713{
 714        machine_ops.power_off();
 715}
 716
 717void machine_shutdown(void)
 718{
 719        machine_ops.shutdown();
 720}
 721
 722void machine_emergency_restart(void)
 723{
 724        __machine_emergency_restart(1);
 725}
 726
 727void machine_restart(char *cmd)
 728{
 729        machine_ops.restart(cmd);
 730}
 731
 732void machine_halt(void)
 733{
 734        machine_ops.halt();
 735}
 736
 737#ifdef CONFIG_KEXEC
 738void machine_crash_shutdown(struct pt_regs *regs)
 739{
 740        machine_ops.crash_shutdown(regs);
 741}
 742#endif
 743
 744
 745#if defined(CONFIG_SMP)
 746
 747/* This keeps a track of which one is crashing cpu. */
 748static int crashing_cpu;
 749static nmi_shootdown_cb shootdown_callback;
 750
 751static atomic_t waiting_for_crash_ipi;
 752
 753static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 754{
 755        int cpu;
 756
 757        cpu = raw_smp_processor_id();
 758
 759        /*
 760         * Don't do anything if this handler is invoked on crashing cpu.
 761         * Otherwise, system will completely hang. Crashing cpu can get
 762         * an NMI if system was initially booted with nmi_watchdog parameter.
 763         */
 764        if (cpu == crashing_cpu)
 765                return NMI_HANDLED;
 766        local_irq_disable();
 767
 768        shootdown_callback(cpu, regs);
 769
 770        atomic_dec(&waiting_for_crash_ipi);
 771        /* Assume hlt works */
 772        halt();
 773        for (;;)
 774                cpu_relax();
 775
 776        return NMI_HANDLED;
 777}
 778
 779static void smp_send_nmi_allbutself(void)
 780{
 781        apic->send_IPI_allbutself(NMI_VECTOR);
 782}
 783
 784/*
 785 * Halt all other CPUs, calling the specified function on each of them
 786 *
 787 * This function can be used to halt all other CPUs on crash
 788 * or emergency reboot time. The function passed as parameter
 789 * will be called inside a NMI handler on all CPUs.
 790 */
 791void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 792{
 793        unsigned long msecs;
 794        local_irq_disable();
 795
 796        /* Make a note of crashing cpu. Will be used in NMI callback. */
 797        crashing_cpu = safe_smp_processor_id();
 798
 799        shootdown_callback = callback;
 800
 801        atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 802        /* Would it be better to replace the trap vector here? */
 803        if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 804                                 NMI_FLAG_FIRST, "crash"))
 805                return;         /* Return what? */
 806        /*
 807         * Ensure the new callback function is set before sending
 808         * out the NMI
 809         */
 810        wmb();
 811
 812        smp_send_nmi_allbutself();
 813
 814        msecs = 1000; /* Wait at most a second for the other cpus to stop */
 815        while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 816                mdelay(1);
 817                msecs--;
 818        }
 819
 820        /* Leave the nmi callback set */
 821}
 822#else /* !CONFIG_SMP */
 823void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 824{
 825        /* No other CPUs to shoot down */
 826}
 827#endif
 828
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