arch/x86/kernel/reboot.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   3
   4 #include <linux/export.h>
   5 #include <linux/reboot.h>
   6 #include <linux/init.h>
   7 #include <linux/pm.h>
   8 #include <linux/efi.h>
   9 #include <linux/dmi.h>
  10 #include <linux/sched.h>
  11 #include <linux/tboot.h>
  12 #include <linux/delay.h>
  13 #include <linux/frame.h>
  14 #include <acpi/reboot.h>
  15 #include <asm/io.h>
  16 #include <asm/apic.h>
  17 #include <asm/io_apic.h>
  18 #include <asm/desc.h>
  19 #include <asm/hpet.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/proto.h>
  22 #include <asm/reboot_fixups.h>
  23 #include <asm/reboot.h>
  24 #include <asm/pci_x86.h>
  25 #include <asm/virtext.h>
  26 #include <asm/cpu.h>
  27 #include <asm/nmi.h>
  28 #include <asm/smp.h>
  29
  30 #include <linux/ctype.h>
  31 #include <linux/mc146818rtc.h>
  32 #include <asm/realmode.h>
  33 #include <asm/x86_init.h>
  34 #include <asm/efi.h>
  35
  36 /*
  37  * Power off function, if any
  38  */
  39 void (*pm_power_off)(void);
  40 EXPORT_SYMBOL(pm_power_off);
  41
  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 /*
  53  * Reboot options and system auto-detection code provided by
  54  * Dell Inc. so their systems "just work". :-)
  55  */
  56
  57 /*
  58  * Some machines require the "reboot=a" commandline options
  59  */
  60 static int __init set_acpi_reboot(const struct dmi_system_id *d)
  61 {
  62         if (reboot_type != BOOT_ACPI) {
  63                 reboot_type = BOOT_ACPI;
  64                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  65                         d->ident, "ACPI");
  66         }
  67         return 0;
  68 }
  69
  70 /*
  71  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
  72  * this quirk makes that automatic.
  73  */
  74 static int __init set_bios_reboot(const struct dmi_system_id *d)
  75 {
  76         if (reboot_type != BOOT_BIOS) {
  77                 reboot_type = BOOT_BIOS;
  78                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
  79                         d->ident, "BIOS");
  80         }
  81         return 0;
  82 }
  83
  84 void __noreturn machine_real_restart(unsigned int type)
  85 {
  86         local_irq_disable();
  87
  88         /*
  89          * Write zero to CMOS register number 0x0f, which the BIOS POST
  90          * routine will recognize as telling it to do a proper reboot.  (Well
  91          * that's what this book in front of me says -- it may only apply to
  92          * the Phoenix BIOS though, it's not clear).  At the same time,
  93          * disable NMIs by setting the top bit in the CMOS address register,
  94          * as we're about to do peculiar things to the CPU.  I'm not sure if
  95          * `outb_p' is needed instead of just `outb'.  Use it to be on the
  96          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
  97          */
  98         spin_lock(&rtc_lock);
  99         CMOS_WRITE(0x00, 0x8f);
 100         spin_unlock(&rtc_lock);
 101
 102         /*
 103          * Switch back to the initial page table.
 104          */
 105 #ifdef CONFIG_X86_32
 106         load_cr3(initial_page_table);
 107 #else
 108         write_cr3(real_mode_header->trampoline_pgd);
 109
 110         /* Exiting long mode will fail if CR4.PCIDE is set. */
 111         if (static_cpu_has(X86_FEATURE_PCID))
 112                 cr4_clear_bits(X86_CR4_PCIDE);
 113 #endif
 114
 115         /* Jump to the identity-mapped low memory code */
 116 #ifdef CONFIG_X86_32
 117         asm volatile("jmpl *%0" : :
 118                      "rm" (real_mode_header->machine_real_restart_asm),
 119                      "a" (type));
 120 #else
 121         asm volatile("ljmpl *%0" : :
 122                      "m" (real_mode_header->machine_real_restart_asm),
 123                      "D" (type));
 124 #endif
 125         unreachable();
 126 }
 127 #ifdef CONFIG_APM_MODULE
 128 EXPORT_SYMBOL(machine_real_restart);
 129 #endif
 130 STACK_FRAME_NON_STANDARD(machine_real_restart);
 131
 132 /*
 133  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 134  */
 135 static int __init set_pci_reboot(const struct dmi_system_id *d)
 136 {
 137         if (reboot_type != BOOT_CF9_FORCE) {
 138                 reboot_type = BOOT_CF9_FORCE;
 139                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 140                         d->ident, "PCI");
 141         }
 142         return 0;
 143 }
 144
 145 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 146 {
 147         if (reboot_type != BOOT_KBD) {
 148                 reboot_type = BOOT_KBD;
 149                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 150                         d->ident, "KBD");
 151         }
 152         return 0;
 153 }
 154
 155 /*
 156  * This is a single dmi_table handling all reboot quirks.
 157  */
 158 static const struct dmi_system_id reboot_dmi_table[] __initconst = {
 159
 160         /* Acer */
 161         {       /* Handle reboot issue on Acer Aspire one */
 162                 .callback = set_kbd_reboot,
 163                 .ident = "Acer Aspire One A110",
 164                 .matches = {
 165                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 166                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 167                 },
 168         },
 169
 170         /* Apple */
 171         {       /* Handle problems with rebooting on Apple MacBook5 */
 172                 .callback = set_pci_reboot,
 173                 .ident = "Apple MacBook5",
 174                 .matches = {
 175                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 176                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 177                 },
 178         },
 179         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 180                 .callback = set_pci_reboot,
 181                 .ident = "Apple MacBookPro5",
 182                 .matches = {
 183                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 184                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 185                 },
 186         },
 187         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 188                 .callback = set_pci_reboot,
 189                 .ident = "Apple Macmini3,1",
 190                 .matches = {
 191                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 192                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 193                 },
 194         },
 195         {       /* Handle problems with rebooting on the iMac9,1. */
 196                 .callback = set_pci_reboot,
 197                 .ident = "Apple iMac9,1",
 198                 .matches = {
 199                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 200                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 201                 },
 202         },
 203         {       /* Handle problems with rebooting on the iMac10,1. */
 204                 .callback = set_pci_reboot,
 205                 .ident = "Apple iMac10,1",
 206                 .matches = {
 207                     DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 208                     DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
 209                 },
 210         },
 211
 212         /* ASRock */
 213         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
 214                 .callback = set_pci_reboot,
 215                 .ident = "ASRock Q1900DC-ITX",
 216                 .matches = {
 217                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
 218                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
 219                 },
 220         },
 221
 222         /* ASUS */
 223         {       /* Handle problems with rebooting on ASUS P4S800 */
 224                 .callback = set_bios_reboot,
 225                 .ident = "ASUS P4S800",
 226                 .matches = {
 227                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 228                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 229                 },
 230         },
 231         {       /* Handle problems with rebooting on ASUS EeeBook X205TA */
 232                 .callback = set_acpi_reboot,
 233                 .ident = "ASUS EeeBook X205TA",
 234                 .matches = {
 235                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 236                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
 237                 },
 238         },
 239         {       /* Handle problems with rebooting on ASUS EeeBook X205TAW */
 240                 .callback = set_acpi_reboot,
 241                 .ident = "ASUS EeeBook X205TAW",
 242                 .matches = {
 243                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 244                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
 245                 },
 246         },
 247
 248         /* Certec */
 249         {       /* Handle problems with rebooting on Certec BPC600 */
 250                 .callback = set_pci_reboot,
 251                 .ident = "Certec BPC600",
 252                 .matches = {
 253                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 254                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 255                 },
 256         },
 257
 258         /* Dell */
 259         {       /* Handle problems with rebooting on Dell DXP061 */
 260                 .callback = set_bios_reboot,
 261                 .ident = "Dell DXP061",
 262                 .matches = {
 263                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 264                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 265                 },
 266         },
 267         {       /* Handle problems with rebooting on Dell E520's */
 268                 .callback = set_bios_reboot,
 269                 .ident = "Dell E520",
 270                 .matches = {
 271                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 272                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 273                 },
 274         },
 275         {       /* Handle problems with rebooting on the Latitude E5410. */
 276                 .callback = set_pci_reboot,
 277                 .ident = "Dell Latitude E5410",
 278                 .matches = {
 279                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 280                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 281                 },
 282         },
 283         {       /* Handle problems with rebooting on the Latitude E5420. */
 284                 .callback = set_pci_reboot,
 285                 .ident = "Dell Latitude E5420",
 286                 .matches = {
 287                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 288                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 289                 },
 290         },
 291         {       /* Handle problems with rebooting on the Latitude E6320. */
 292                 .callback = set_pci_reboot,
 293                 .ident = "Dell Latitude E6320",
 294                 .matches = {
 295                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 296                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 297                 },
 298         },
 299         {       /* Handle problems with rebooting on the Latitude E6420. */
 300                 .callback = set_pci_reboot,
 301                 .ident = "Dell Latitude E6420",
 302                 .matches = {
 303                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 304                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 305                 },
 306         },
 307         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 308                 .callback = set_bios_reboot,
 309                 .ident = "Dell OptiPlex 330",
 310                 .matches = {
 311                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 312                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 313                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 314                 },
 315         },
 316         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 317                 .callback = set_bios_reboot,
 318                 .ident = "Dell OptiPlex 360",
 319                 .matches = {
 320                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 321                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 322                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 323                 },
 324         },
 325         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 326                 .callback = set_bios_reboot,
 327                 .ident = "Dell OptiPlex 745",
 328                 .matches = {
 329                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 330                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 331                 },
 332         },
 333         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 334                 .callback = set_bios_reboot,
 335                 .ident = "Dell OptiPlex 745",
 336                 .matches = {
 337                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 338                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 339                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 340                 },
 341         },
 342         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 343                 .callback = set_bios_reboot,
 344                 .ident = "Dell OptiPlex 745",
 345                 .matches = {
 346                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 347                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 348                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 349                 },
 350         },
 351         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 352                 .callback = set_bios_reboot,
 353                 .ident = "Dell OptiPlex 760",
 354                 .matches = {
 355                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 356                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 357                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 358                 },
 359         },
 360         {       /* Handle problems with rebooting on the OptiPlex 990. */
 361                 .callback = set_pci_reboot,
 362                 .ident = "Dell OptiPlex 990",
 363                 .matches = {
 364                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 365                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 366                 },
 367         },
 368         {       /* Handle problems with rebooting on Dell 300's */
 369                 .callback = set_bios_reboot,
 370                 .ident = "Dell PowerEdge 300",
 371                 .matches = {
 372                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 373                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 374                 },
 375         },
 376         {       /* Handle problems with rebooting on Dell 1300's */
 377                 .callback = set_bios_reboot,
 378                 .ident = "Dell PowerEdge 1300",
 379                 .matches = {
 380                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 381                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 382                 },
 383         },
 384         {       /* Handle problems with rebooting on Dell 2400's */
 385                 .callback = set_bios_reboot,
 386                 .ident = "Dell PowerEdge 2400",
 387                 .matches = {
 388                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 389                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 390                 },
 391         },
 392         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 393                 .callback = set_pci_reboot,
 394                 .ident = "Dell PowerEdge C6100",
 395                 .matches = {
 396                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 397                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 398                 },
 399         },
 400         {       /* Handle problems with rebooting on the Precision M6600. */
 401                 .callback = set_pci_reboot,
 402                 .ident = "Dell Precision M6600",
 403                 .matches = {
 404                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 405                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 406                 },
 407         },
 408         {       /* Handle problems with rebooting on Dell T5400's */
 409                 .callback = set_bios_reboot,
 410                 .ident = "Dell Precision T5400",
 411                 .matches = {
 412                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 413                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 414                 },
 415         },
 416         {       /* Handle problems with rebooting on Dell T7400's */
 417                 .callback = set_bios_reboot,
 418                 .ident = "Dell Precision T7400",
 419                 .matches = {
 420                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 421                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 422                 },
 423         },
 424         {       /* Handle problems with rebooting on Dell XPS710 */
 425                 .callback = set_bios_reboot,
 426                 .ident = "Dell XPS710",
 427                 .matches = {
 428                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 429                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 430                 },
 431         },
 432         {       /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
 433                 .callback = set_acpi_reboot,
 434                 .ident = "Dell OptiPlex 7450 AIO",
 435                 .matches = {
 436                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 437                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
 438                 },
 439         },
 440
 441         /* Hewlett-Packard */
 442         {       /* Handle problems with rebooting on HP laptops */
 443                 .callback = set_bios_reboot,
 444                 .ident = "HP Compaq Laptop",
 445                 .matches = {
 446                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 447                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 448                 },
 449         },
 450
 451         /* Sony */
 452         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 453                 .callback = set_bios_reboot,
 454                 .ident = "Sony VGN-Z540N",
 455                 .matches = {
 456                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 457                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 458                 },
 459         },
 460
 461         { }
 462 };
 463
 464 static int __init reboot_init(void)
 465 {
 466         int rv;
 467
 468         /*
 469          * Only do the DMI check if reboot_type hasn't been overridden
 470          * on the command line
 471          */
 472         if (!reboot_default)
 473                 return 0;
 474
 475         /*
 476          * The DMI quirks table takes precedence. If no quirks entry
 477          * matches and the ACPI Hardware Reduced bit is set and EFI
 478          * runtime services are enabled, force EFI reboot.
 479          */
 480         rv = dmi_check_system(reboot_dmi_table);
 481
 482         if (!rv && efi_reboot_required() && !efi_runtime_disabled())
 483                 reboot_type = BOOT_EFI;
 484
 485         return 0;
 486 }
 487 core_initcall(reboot_init);
 488
 489 static inline void kb_wait(void)
 490 {
 491         int i;
 492
 493         for (i = 0; i < 0x10000; i++) {
 494                 if ((inb(0x64) & 0x02) == 0)
 495                         break;
 496                 udelay(2);
 497         }
 498 }
 499
 500 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 501 {
 502         cpu_emergency_vmxoff();
 503 }
 504
 505 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 506 static void emergency_vmx_disable_all(void)
 507 {
 508         /* Just make sure we won't change CPUs while doing this */
 509         local_irq_disable();
 510
 511         /*
 512          * We need to disable VMX on all CPUs before rebooting, otherwise
 513          * we risk hanging up the machine, because the CPU ignore INIT
 514          * signals when VMX is enabled.
 515          *
 516          * We can't take any locks and we may be on an inconsistent
 517          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 518          * VMX and halt.
 519          *
 520          * For safety, we will avoid running the nmi_shootdown_cpus()
 521          * stuff unnecessarily, but we don't have a way to check
 522          * if other CPUs have VMX enabled. So we will call it only if the
 523          * CPU we are running on has VMX enabled.
 524          *
 525          * We will miss cases where VMX is not enabled on all CPUs. This
 526          * shouldn't do much harm because KVM always enable VMX on all
 527          * CPUs anyway. But we can miss it on the small window where KVM
 528          * is still enabling VMX.
 529          */
 530         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 531                 /* Disable VMX on this CPU. */
 532                 cpu_vmxoff();
 533
 534                 /* Halt and disable VMX on the other CPUs */
 535                 nmi_shootdown_cpus(vmxoff_nmi);
 536
 537         }
 538 }
 539
 540
 541 void __attribute__((weak)) mach_reboot_fixups(void)
 542 {
 543 }
 544
 545 /*
 546  * To the best of our knowledge Windows compatible x86 hardware expects
 547  * the following on reboot:
 548  *
 549  * 1) If the FADT has the ACPI reboot register flag set, try it
 550  * 2) If still alive, write to the keyboard controller
 551  * 3) If still alive, write to the ACPI reboot register again
 552  * 4) If still alive, write to the keyboard controller again
 553  * 5) If still alive, call the EFI runtime service to reboot
 554  * 6) If no EFI runtime service, call the BIOS to do a reboot
 555  *
 556  * We default to following the same pattern. We also have
 557  * two other reboot methods: 'triple fault' and 'PCI', which
 558  * can be triggered via the reboot= kernel boot option or
 559  * via quirks.
 560  *
 561  * This means that this function can never return, it can misbehave
 562  * by not rebooting properly and hanging.
 563  */
 564 static void native_machine_emergency_restart(void)
 565 {
 566         int i;
 567         int attempt = 0;
 568         int orig_reboot_type = reboot_type;
 569         unsigned short mode;
 570
 571         if (reboot_emergency)
 572                 emergency_vmx_disable_all();
 573
 574         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 575
 576         /* Tell the BIOS if we want cold or warm reboot */
 577         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 578         *((unsigned short *)__va(0x472)) = mode;
 579
 580         /*
 581          * If an EFI capsule has been registered with the firmware then
 582          * override the reboot= parameter.
 583          */
 584         if (efi_capsule_pending(NULL)) {
 585                 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
 586                 reboot_type = BOOT_EFI;
 587         }
 588
 589         for (;;) {
 590                 /* Could also try the reset bit in the Hammer NB */
 591                 switch (reboot_type) {
 592                 case BOOT_ACPI:
 593                         acpi_reboot();
 594                         reboot_type = BOOT_KBD;
 595                         break;
 596
 597                 case BOOT_KBD:
 598                         mach_reboot_fixups(); /* For board specific fixups */
 599
 600                         for (i = 0; i < 10; i++) {
 601                                 kb_wait();
 602                                 udelay(50);
 603                                 outb(0xfe, 0x64); /* Pulse reset low */
 604                                 udelay(50);
 605                         }
 606                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 607                                 attempt = 1;
 608                                 reboot_type = BOOT_ACPI;
 609                         } else {
 610                                 reboot_type = BOOT_EFI;
 611                         }
 612                         break;
 613
 614                 case BOOT_EFI:
 615                         efi_reboot(reboot_mode, NULL);
 616                         reboot_type = BOOT_BIOS;
 617                         break;
 618
 619                 case BOOT_BIOS:
 620                         machine_real_restart(MRR_BIOS);
 621
 622                         /* We're probably dead after this, but... */
 623                         reboot_type = BOOT_CF9_SAFE;
 624                         break;
 625
 626                 case BOOT_CF9_FORCE:
 627                         port_cf9_safe = true;
 628                         /* Fall through */
 629
 630                 case BOOT_CF9_SAFE:
 631                         if (port_cf9_safe) {
 632                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 633                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 634                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 635                                 udelay(50);
 636                                 /* Actually do the reset */
 637                                 outb(cf9|reboot_code, 0xcf9);
 638                                 udelay(50);
 639                         }
 640                         reboot_type = BOOT_TRIPLE;
 641                         break;
 642
 643                 case BOOT_TRIPLE:
 644                         idt_invalidate(NULL);
 645                         __asm__ __volatile__("int3");
 646
 647                         /* We're probably dead after this, but... */
 648                         reboot_type = BOOT_KBD;
 649                         break;
 650                 }
 651         }
 652 }
 653
 654 void native_machine_shutdown(void)
 655 {
 656         /* Stop the cpus and apics */
 657 #ifdef CONFIG_X86_IO_APIC
 658         /*
 659          * Disabling IO APIC before local APIC is a workaround for
 660          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 661          * Specification Update". In this situation, interrupts that target
 662          * a Logical Processor whose Local APIC is either in the process of
 663          * being hardware disabled or software disabled are neither delivered
 664          * nor discarded. When this erratum occurs, the processor may hang.
 665          *
 666          * Even without the erratum, it still makes sense to quiet IO APIC
 667          * before disabling Local APIC.
 668          */
 669         disable_IO_APIC();
 670 #endif
 671
 672 #ifdef CONFIG_SMP
 673         /*
 674          * Stop all of the others. Also disable the local irq to
 675          * not receive the per-cpu timer interrupt which may trigger
 676          * scheduler's load balance.
 677          */
 678         local_irq_disable();
 679         stop_other_cpus();
 680 #endif
 681
 682         lapic_shutdown();
 683
 684 #ifdef CONFIG_HPET_TIMER
 685         hpet_disable();
 686 #endif
 687
 688 #ifdef CONFIG_X86_64
 689         x86_platform.iommu_shutdown();
 690 #endif
 691 }
 692
 693 static void __machine_emergency_restart(int emergency)
 694 {
 695         reboot_emergency = emergency;
 696         machine_ops.emergency_restart();
 697 }
 698
 699 static void native_machine_restart(char *__unused)
 700 {
 701         pr_notice("machine restart\n");
 702
 703         if (!reboot_force)
 704                 machine_shutdown();
 705         __machine_emergency_restart(0);
 706 }
 707
 708 static void native_machine_halt(void)
 709 {
 710         /* Stop other cpus and apics */
 711         machine_shutdown();
 712
 713         tboot_shutdown(TB_SHUTDOWN_HALT);
 714
 715         stop_this_cpu(NULL);
 716 }
 717
 718 static void native_machine_power_off(void)
 719 {
 720         if (pm_power_off) {
 721                 if (!reboot_force)
 722                         machine_shutdown();
 723                 pm_power_off();
 724         }
 725         /* A fallback in case there is no PM info available */
 726         tboot_shutdown(TB_SHUTDOWN_HALT);
 727 }
 728
 729 struct machine_ops machine_ops __ro_after_init = {
 730         .power_off = native_machine_power_off,
 731         .shutdown = native_machine_shutdown,
 732         .emergency_restart = native_machine_emergency_restart,
 733         .restart = native_machine_restart,
 734         .halt = native_machine_halt,
 735 #ifdef CONFIG_KEXEC_CORE
 736         .crash_shutdown = native_machine_crash_shutdown,
 737 #endif
 738 };
 739
 740 void machine_power_off(void)
 741 {
 742         machine_ops.power_off();
 743 }
 744
 745 void machine_shutdown(void)
 746 {
 747         machine_ops.shutdown();
 748 }
 749
 750 void machine_emergency_restart(void)
 751 {
 752         __machine_emergency_restart(1);
 753 }
 754
 755 void machine_restart(char *cmd)
 756 {
 757         machine_ops.restart(cmd);
 758 }
 759
 760 void machine_halt(void)
 761 {
 762         machine_ops.halt();
 763 }
 764
 765 #ifdef CONFIG_KEXEC_CORE
 766 void machine_crash_shutdown(struct pt_regs *regs)
 767 {
 768         machine_ops.crash_shutdown(regs);
 769 }
 770 #endif
 771
 772
 773 /* This is the CPU performing the emergency shutdown work. */
 774 int crashing_cpu = -1;
 775
 776 #if defined(CONFIG_SMP)
 777
 778 static nmi_shootdown_cb shootdown_callback;
 779
 780 static atomic_t waiting_for_crash_ipi;
 781 static int crash_ipi_issued;
 782
 783 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 784 {
 785         int cpu;
 786
 787         cpu = raw_smp_processor_id();
 788
 789         /*
 790          * Don't do anything if this handler is invoked on crashing cpu.
 791          * Otherwise, system will completely hang. Crashing cpu can get
 792          * an NMI if system was initially booted with nmi_watchdog parameter.
 793          */
 794         if (cpu == crashing_cpu)
 795                 return NMI_HANDLED;
 796         local_irq_disable();
 797
 798         shootdown_callback(cpu, regs);
 799
 800         atomic_dec(&waiting_for_crash_ipi);
 801         /* Assume hlt works */
 802         halt();
 803         for (;;)
 804                 cpu_relax();
 805
 806         return NMI_HANDLED;
 807 }
 808
 809 static void smp_send_nmi_allbutself(void)
 810 {
 811         apic->send_IPI_allbutself(NMI_VECTOR);
 812 }
 813
 814 /*
 815  * Halt all other CPUs, calling the specified function on each of them
 816  *
 817  * This function can be used to halt all other CPUs on crash
 818  * or emergency reboot time. The function passed as parameter
 819  * will be called inside a NMI handler on all CPUs.
 820  */
 821 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 822 {
 823         unsigned long msecs;
 824         local_irq_disable();
 825
 826         /* Make a note of crashing cpu. Will be used in NMI callback. */
 827         crashing_cpu = safe_smp_processor_id();
 828
 829         shootdown_callback = callback;
 830
 831         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 832         /* Would it be better to replace the trap vector here? */
 833         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 834                                  NMI_FLAG_FIRST, "crash"))
 835                 return;         /* Return what? */
 836         /*
 837          * Ensure the new callback function is set before sending
 838          * out the NMI
 839          */
 840         wmb();
 841
 842         smp_send_nmi_allbutself();
 843
 844         /* Kick CPUs looping in NMI context. */
 845         WRITE_ONCE(crash_ipi_issued, 1);
 846
 847         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 848         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 849                 mdelay(1);
 850                 msecs--;
 851         }
 852
 853         /* Leave the nmi callback set */
 854 }
 855
 856 /*
 857  * Check if the crash dumping IPI got issued and if so, call its callback
 858  * directly. This function is used when we have already been in NMI handler.
 859  * It doesn't return.
 860  */
 861 void run_crash_ipi_callback(struct pt_regs *regs)
 862 {
 863         if (crash_ipi_issued)
 864                 crash_nmi_callback(0, regs);
 865 }
 866
 867 /* Override the weak function in kernel/panic.c */
 868 void nmi_panic_self_stop(struct pt_regs *regs)
 869 {
 870         while (1) {
 871                 /* If no CPU is preparing crash dump, we simply loop here. */
 872                 run_crash_ipi_callback(regs);
 873                 cpu_relax();
 874         }
 875 }
 876
 877 #else /* !CONFIG_SMP */
 878 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 879 {
 880         /* No other CPUs to shoot down */
 881 }
 882
 883 void run_crash_ipi_callback(struct pt_regs *regs)
 884 {
 885 }
 886 #endif