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/objtool.h>
  14 #include <linux/pgtable.h>
  15 #include <linux/kexec.h>
  16 #include <acpi/reboot.h>
  17 #include <asm/io.h>
  18 #include <asm/apic.h>
  19 #include <asm/io_apic.h>
  20 #include <asm/desc.h>
  21 #include <asm/hpet.h>
  22 #include <asm/proto.h>
  23 #include <asm/reboot_fixups.h>
  24 #include <asm/reboot.h>
  25 #include <asm/pci_x86.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 /*
  85  * Some machines don't handle the default ACPI reboot method and
  86  * require the EFI reboot method:
  87  */
  88 static int __init set_efi_reboot(const struct dmi_system_id *d)
  89 {
  90         if (reboot_type != BOOT_EFI && !efi_runtime_disabled()) {
  91                 reboot_type = BOOT_EFI;
  92                 pr_info("%s series board detected. Selecting EFI-method for reboot.\n", d->ident);
  93         }
  94         return 0;
  95 }
  96
  97 void __noreturn machine_real_restart(unsigned int type)
  98 {
  99         local_irq_disable();
 100
 101         /*
 102          * Write zero to CMOS register number 0x0f, which the BIOS POST
 103          * routine will recognize as telling it to do a proper reboot.  (Well
 104          * that's what this book in front of me says -- it may only apply to
 105          * the Phoenix BIOS though, it's not clear).  At the same time,
 106          * disable NMIs by setting the top bit in the CMOS address register,
 107          * as we're about to do peculiar things to the CPU.  I'm not sure if
 108          * `outb_p' is needed instead of just `outb'.  Use it to be on the
 109          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 110          */
 111         spin_lock(&rtc_lock);
 112         CMOS_WRITE(0x00, 0x8f);
 113         spin_unlock(&rtc_lock);
 114
 115         /*
 116          * Switch to the trampoline page table.
 117          */
 118         load_trampoline_pgtable();
 119
 120         /* Jump to the identity-mapped low memory code */
 121 #ifdef CONFIG_X86_32
 122         asm volatile("jmpl *%0" : :
 123                      "rm" (real_mode_header->machine_real_restart_asm),
 124                      "a" (type));
 125 #else
 126         asm volatile("ljmpl *%0" : :
 127                      "m" (real_mode_header->machine_real_restart_asm),
 128                      "D" (type));
 129 #endif
 130         unreachable();
 131 }
 132 #ifdef CONFIG_APM_MODULE
 133 EXPORT_SYMBOL(machine_real_restart);
 134 #endif
 135 STACK_FRAME_NON_STANDARD(machine_real_restart);
 136
 137 /*
 138  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 139  */
 140 static int __init set_pci_reboot(const struct dmi_system_id *d)
 141 {
 142         if (reboot_type != BOOT_CF9_FORCE) {
 143                 reboot_type = BOOT_CF9_FORCE;
 144                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 145                         d->ident, "PCI");
 146         }
 147         return 0;
 148 }
 149
 150 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 151 {
 152         if (reboot_type != BOOT_KBD) {
 153                 reboot_type = BOOT_KBD;
 154                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 155                         d->ident, "KBD");
 156         }
 157         return 0;
 158 }
 159
 160 /*
 161  * This is a single dmi_table handling all reboot quirks.
 162  */
 163 static const struct dmi_system_id reboot_dmi_table[] __initconst = {
 164
 165         /* Acer */
 166         {       /* Handle reboot issue on Acer Aspire one */
 167                 .callback = set_kbd_reboot,
 168                 .ident = "Acer Aspire One A110",
 169                 .matches = {
 170                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 171                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 172                 },
 173         },
 174         {       /* Handle reboot issue on Acer TravelMate X514-51T */
 175                 .callback = set_efi_reboot,
 176                 .ident = "Acer TravelMate X514-51T",
 177                 .matches = {
 178                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 179                         DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate X514-51T"),
 180                 },
 181         },
 182
 183         /* Apple */
 184         {       /* Handle problems with rebooting on Apple MacBook5 */
 185                 .callback = set_pci_reboot,
 186                 .ident = "Apple MacBook5",
 187                 .matches = {
 188                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 189                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 190                 },
 191         },
 192         {       /* Handle problems with rebooting on Apple MacBook6,1 */
 193                 .callback = set_pci_reboot,
 194                 .ident = "Apple MacBook6,1",
 195                 .matches = {
 196                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 197                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook6,1"),
 198                 },
 199         },
 200         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 201                 .callback = set_pci_reboot,
 202                 .ident = "Apple MacBookPro5",
 203                 .matches = {
 204                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 205                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 206                 },
 207         },
 208         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 209                 .callback = set_pci_reboot,
 210                 .ident = "Apple Macmini3,1",
 211                 .matches = {
 212                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 213                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 214                 },
 215         },
 216         {       /* Handle problems with rebooting on the iMac9,1. */
 217                 .callback = set_pci_reboot,
 218                 .ident = "Apple iMac9,1",
 219                 .matches = {
 220                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 221                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 222                 },
 223         },
 224         {       /* Handle problems with rebooting on the iMac10,1. */
 225                 .callback = set_pci_reboot,
 226                 .ident = "Apple iMac10,1",
 227                 .matches = {
 228                     DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 229                     DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
 230                 },
 231         },
 232
 233         /* ASRock */
 234         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
 235                 .callback = set_pci_reboot,
 236                 .ident = "ASRock Q1900DC-ITX",
 237                 .matches = {
 238                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
 239                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
 240                 },
 241         },
 242
 243         /* ASUS */
 244         {       /* Handle problems with rebooting on ASUS P4S800 */
 245                 .callback = set_bios_reboot,
 246                 .ident = "ASUS P4S800",
 247                 .matches = {
 248                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 249                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 250                 },
 251         },
 252         {       /* Handle problems with rebooting on ASUS EeeBook X205TA */
 253                 .callback = set_acpi_reboot,
 254                 .ident = "ASUS EeeBook X205TA",
 255                 .matches = {
 256                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 257                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
 258                 },
 259         },
 260         {       /* Handle problems with rebooting on ASUS EeeBook X205TAW */
 261                 .callback = set_acpi_reboot,
 262                 .ident = "ASUS EeeBook X205TAW",
 263                 .matches = {
 264                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 265                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
 266                 },
 267         },
 268
 269         /* Certec */
 270         {       /* Handle problems with rebooting on Certec BPC600 */
 271                 .callback = set_pci_reboot,
 272                 .ident = "Certec BPC600",
 273                 .matches = {
 274                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 275                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 276                 },
 277         },
 278
 279         /* Dell */
 280         {       /* Handle problems with rebooting on Dell DXP061 */
 281                 .callback = set_bios_reboot,
 282                 .ident = "Dell DXP061",
 283                 .matches = {
 284                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 285                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 286                 },
 287         },
 288         {       /* Handle problems with rebooting on Dell E520's */
 289                 .callback = set_bios_reboot,
 290                 .ident = "Dell E520",
 291                 .matches = {
 292                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 293                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 294                 },
 295         },
 296         {       /* Handle problems with rebooting on the Latitude E5410. */
 297                 .callback = set_pci_reboot,
 298                 .ident = "Dell Latitude E5410",
 299                 .matches = {
 300                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 301                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 302                 },
 303         },
 304         {       /* Handle problems with rebooting on the Latitude E5420. */
 305                 .callback = set_pci_reboot,
 306                 .ident = "Dell Latitude E5420",
 307                 .matches = {
 308                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 309                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 310                 },
 311         },
 312         {       /* Handle problems with rebooting on the Latitude E6320. */
 313                 .callback = set_pci_reboot,
 314                 .ident = "Dell Latitude E6320",
 315                 .matches = {
 316                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 317                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 318                 },
 319         },
 320         {       /* Handle problems with rebooting on the Latitude E6420. */
 321                 .callback = set_pci_reboot,
 322                 .ident = "Dell Latitude E6420",
 323                 .matches = {
 324                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 325                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 326                 },
 327         },
 328         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 329                 .callback = set_bios_reboot,
 330                 .ident = "Dell OptiPlex 330",
 331                 .matches = {
 332                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 333                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 334                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 335                 },
 336         },
 337         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 338                 .callback = set_bios_reboot,
 339                 .ident = "Dell OptiPlex 360",
 340                 .matches = {
 341                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 342                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 343                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 344                 },
 345         },
 346         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 347                 .callback = set_bios_reboot,
 348                 .ident = "Dell OptiPlex 745",
 349                 .matches = {
 350                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 351                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 352                 },
 353         },
 354         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 355                 .callback = set_bios_reboot,
 356                 .ident = "Dell OptiPlex 745",
 357                 .matches = {
 358                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 359                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 360                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 361                 },
 362         },
 363         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 364                 .callback = set_bios_reboot,
 365                 .ident = "Dell OptiPlex 745",
 366                 .matches = {
 367                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 368                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 369                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 370                 },
 371         },
 372         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 373                 .callback = set_bios_reboot,
 374                 .ident = "Dell OptiPlex 760",
 375                 .matches = {
 376                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 377                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 378                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 379                 },
 380         },
 381         {       /* Handle problems with rebooting on the OptiPlex 990. */
 382                 .callback = set_pci_reboot,
 383                 .ident = "Dell OptiPlex 990 BIOS A0x",
 384                 .matches = {
 385                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 386                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 387                         DMI_MATCH(DMI_BIOS_VERSION, "A0"),
 388                 },
 389         },
 390         {       /* Handle problems with rebooting on Dell 300's */
 391                 .callback = set_bios_reboot,
 392                 .ident = "Dell PowerEdge 300",
 393                 .matches = {
 394                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 395                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 396                 },
 397         },
 398         {       /* Handle problems with rebooting on Dell 1300's */
 399                 .callback = set_bios_reboot,
 400                 .ident = "Dell PowerEdge 1300",
 401                 .matches = {
 402                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 403                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 404                 },
 405         },
 406         {       /* Handle problems with rebooting on Dell 2400's */
 407                 .callback = set_bios_reboot,
 408                 .ident = "Dell PowerEdge 2400",
 409                 .matches = {
 410                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 411                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 412                 },
 413         },
 414         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 415                 .callback = set_pci_reboot,
 416                 .ident = "Dell PowerEdge C6100",
 417                 .matches = {
 418                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 419                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 420                 },
 421         },
 422         {       /* Handle problems with rebooting on the Precision M6600. */
 423                 .callback = set_pci_reboot,
 424                 .ident = "Dell Precision M6600",
 425                 .matches = {
 426                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 427                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 428                 },
 429         },
 430         {       /* Handle problems with rebooting on Dell T5400's */
 431                 .callback = set_bios_reboot,
 432                 .ident = "Dell Precision T5400",
 433                 .matches = {
 434                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 435                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 436                 },
 437         },
 438         {       /* Handle problems with rebooting on Dell T7400's */
 439                 .callback = set_bios_reboot,
 440                 .ident = "Dell Precision T7400",
 441                 .matches = {
 442                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 443                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 444                 },
 445         },
 446         {       /* Handle problems with rebooting on Dell XPS710 */
 447                 .callback = set_bios_reboot,
 448                 .ident = "Dell XPS710",
 449                 .matches = {
 450                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 451                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 452                 },
 453         },
 454         {       /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
 455                 .callback = set_acpi_reboot,
 456                 .ident = "Dell OptiPlex 7450 AIO",
 457                 .matches = {
 458                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 459                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
 460                 },
 461         },
 462
 463         /* Hewlett-Packard */
 464         {       /* Handle problems with rebooting on HP laptops */
 465                 .callback = set_bios_reboot,
 466                 .ident = "HP Compaq Laptop",
 467                 .matches = {
 468                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 469                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 470                 },
 471         },
 472
 473         {       /* PCIe Wifi card isn't detected after reboot otherwise */
 474                 .callback = set_pci_reboot,
 475                 .ident = "Zotac ZBOX CI327 nano",
 476                 .matches = {
 477                         DMI_MATCH(DMI_SYS_VENDOR, "NA"),
 478                         DMI_MATCH(DMI_PRODUCT_NAME, "ZBOX-CI327NANO-GS-01"),
 479                 },
 480         },
 481
 482         /* Sony */
 483         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 484                 .callback = set_bios_reboot,
 485                 .ident = "Sony VGN-Z540N",
 486                 .matches = {
 487                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 488                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 489                 },
 490         },
 491
 492         { }
 493 };
 494
 495 static int __init reboot_init(void)
 496 {
 497         int rv;
 498
 499         /*
 500          * Only do the DMI check if reboot_type hasn't been overridden
 501          * on the command line
 502          */
 503         if (!reboot_default)
 504                 return 0;
 505
 506         /*
 507          * The DMI quirks table takes precedence. If no quirks entry
 508          * matches and the ACPI Hardware Reduced bit is set and EFI
 509          * runtime services are enabled, force EFI reboot.
 510          */
 511         rv = dmi_check_system(reboot_dmi_table);
 512
 513         if (!rv && efi_reboot_required() && !efi_runtime_disabled())
 514                 reboot_type = BOOT_EFI;
 515
 516         return 0;
 517 }
 518 core_initcall(reboot_init);
 519
 520 static inline void kb_wait(void)
 521 {
 522         int i;
 523
 524         for (i = 0; i < 0x10000; i++) {
 525                 if ((inb(0x64) & 0x02) == 0)
 526                         break;
 527                 udelay(2);
 528         }
 529 }
 530
 531 static inline void nmi_shootdown_cpus_on_restart(void);
 532
 533 #if IS_ENABLED(CONFIG_KVM_X86)
 534 /* RCU-protected callback to disable virtualization prior to reboot. */
 535 static cpu_emergency_virt_cb __rcu *cpu_emergency_virt_callback;
 536
 537 void cpu_emergency_register_virt_callback(cpu_emergency_virt_cb *callback)
 538 {
 539         if (WARN_ON_ONCE(rcu_access_pointer(cpu_emergency_virt_callback)))
 540                 return;
 541
 542         rcu_assign_pointer(cpu_emergency_virt_callback, callback);
 543 }
 544 EXPORT_SYMBOL_GPL(cpu_emergency_register_virt_callback);
 545
 546 void cpu_emergency_unregister_virt_callback(cpu_emergency_virt_cb *callback)
 547 {
 548         if (WARN_ON_ONCE(rcu_access_pointer(cpu_emergency_virt_callback) != callback))
 549                 return;
 550
 551         rcu_assign_pointer(cpu_emergency_virt_callback, NULL);
 552         synchronize_rcu();
 553 }
 554 EXPORT_SYMBOL_GPL(cpu_emergency_unregister_virt_callback);
 555
 556 /*
 557  * Disable virtualization, i.e. VMX or SVM, to ensure INIT is recognized during
 558  * reboot.  VMX blocks INIT if the CPU is post-VMXON, and SVM blocks INIT if
 559  * GIF=0, i.e. if the crash occurred between CLGI and STGI.
 560  */
 561 void cpu_emergency_disable_virtualization(void)
 562 {
 563         cpu_emergency_virt_cb *callback;
 564
 565         /*
 566          * IRQs must be disabled as KVM enables virtualization in hardware via
 567          * function call IPIs, i.e. IRQs need to be disabled to guarantee
 568          * virtualization stays disabled.
 569          */
 570         lockdep_assert_irqs_disabled();
 571
 572         rcu_read_lock();
 573         callback = rcu_dereference(cpu_emergency_virt_callback);
 574         if (callback)
 575                 callback();
 576         rcu_read_unlock();
 577 }
 578
 579 static void emergency_reboot_disable_virtualization(void)
 580 {
 581         local_irq_disable();
 582
 583         /*
 584          * Disable virtualization on all CPUs before rebooting to avoid hanging
 585          * the system, as VMX and SVM block INIT when running in the host.
 586          *
 587          * We can't take any locks and we may be on an inconsistent state, so
 588          * use NMIs as IPIs to tell the other CPUs to disable VMX/SVM and halt.
 589          *
 590          * Do the NMI shootdown even if virtualization is off on _this_ CPU, as
 591          * other CPUs may have virtualization enabled.
 592          */
 593         if (rcu_access_pointer(cpu_emergency_virt_callback)) {
 594                 /* Safely force _this_ CPU out of VMX/SVM operation. */
 595                 cpu_emergency_disable_virtualization();
 596
 597                 /* Disable VMX/SVM and halt on other CPUs. */
 598                 nmi_shootdown_cpus_on_restart();
 599         }
 600 }
 601 #else
 602 static void emergency_reboot_disable_virtualization(void) { }
 603 #endif /* CONFIG_KVM_X86 */
 604
 605 void __attribute__((weak)) mach_reboot_fixups(void)
 606 {
 607 }
 608
 609 /*
 610  * To the best of our knowledge Windows compatible x86 hardware expects
 611  * the following on reboot:
 612  *
 613  * 1) If the FADT has the ACPI reboot register flag set, try it
 614  * 2) If still alive, write to the keyboard controller
 615  * 3) If still alive, write to the ACPI reboot register again
 616  * 4) If still alive, write to the keyboard controller again
 617  * 5) If still alive, call the EFI runtime service to reboot
 618  * 6) If no EFI runtime service, call the BIOS to do a reboot
 619  *
 620  * We default to following the same pattern. We also have
 621  * two other reboot methods: 'triple fault' and 'PCI', which
 622  * can be triggered via the reboot= kernel boot option or
 623  * via quirks.
 624  *
 625  * This means that this function can never return, it can misbehave
 626  * by not rebooting properly and hanging.
 627  */
 628 static void native_machine_emergency_restart(void)
 629 {
 630         int i;
 631         int attempt = 0;
 632         int orig_reboot_type = reboot_type;
 633         unsigned short mode;
 634
 635         if (reboot_emergency)
 636                 emergency_reboot_disable_virtualization();
 637
 638         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 639
 640         /* Tell the BIOS if we want cold or warm reboot */
 641         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 642         *((unsigned short *)__va(0x472)) = mode;
 643
 644         /*
 645          * If an EFI capsule has been registered with the firmware then
 646          * override the reboot= parameter.
 647          */
 648         if (efi_capsule_pending(NULL)) {
 649                 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
 650                 reboot_type = BOOT_EFI;
 651         }
 652
 653         for (;;) {
 654                 /* Could also try the reset bit in the Hammer NB */
 655                 switch (reboot_type) {
 656                 case BOOT_ACPI:
 657                         acpi_reboot();
 658                         reboot_type = BOOT_KBD;
 659                         break;
 660
 661                 case BOOT_KBD:
 662                         mach_reboot_fixups(); /* For board specific fixups */
 663
 664                         for (i = 0; i < 10; i++) {
 665                                 kb_wait();
 666                                 udelay(50);
 667                                 outb(0xfe, 0x64); /* Pulse reset low */
 668                                 udelay(50);
 669                         }
 670                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 671                                 attempt = 1;
 672                                 reboot_type = BOOT_ACPI;
 673                         } else {
 674                                 reboot_type = BOOT_EFI;
 675                         }
 676                         break;
 677
 678                 case BOOT_EFI:
 679                         efi_reboot(reboot_mode, NULL);
 680                         reboot_type = BOOT_BIOS;
 681                         break;
 682
 683                 case BOOT_BIOS:
 684                         machine_real_restart(MRR_BIOS);
 685
 686                         /* We're probably dead after this, but... */
 687                         reboot_type = BOOT_CF9_SAFE;
 688                         break;
 689
 690                 case BOOT_CF9_FORCE:
 691                         port_cf9_safe = true;
 692                         fallthrough;
 693
 694                 case BOOT_CF9_SAFE:
 695                         if (port_cf9_safe) {
 696                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 697                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 698                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 699                                 udelay(50);
 700                                 /* Actually do the reset */
 701                                 outb(cf9|reboot_code, 0xcf9);
 702                                 udelay(50);
 703                         }
 704                         reboot_type = BOOT_TRIPLE;
 705                         break;
 706
 707                 case BOOT_TRIPLE:
 708                         idt_invalidate();
 709                         __asm__ __volatile__("int3");
 710
 711                         /* We're probably dead after this, but... */
 712                         reboot_type = BOOT_KBD;
 713                         break;
 714                 }
 715         }
 716 }
 717
 718 void native_machine_shutdown(void)
 719 {
 720         /*
 721          * Call enc_kexec_begin() while all CPUs are still active and
 722          * interrupts are enabled. This will allow all in-flight memory
 723          * conversions to finish cleanly.
 724          */
 725         if (kexec_in_progress)
 726                 x86_platform.guest.enc_kexec_begin();
 727
 728         /* Stop the cpus and apics */
 729 #ifdef CONFIG_X86_IO_APIC
 730         /*
 731          * Disabling IO APIC before local APIC is a workaround for
 732          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 733          * Specification Update". In this situation, interrupts that target
 734          * a Logical Processor whose Local APIC is either in the process of
 735          * being hardware disabled or software disabled are neither delivered
 736          * nor discarded. When this erratum occurs, the processor may hang.
 737          *
 738          * Even without the erratum, it still makes sense to quiet IO APIC
 739          * before disabling Local APIC.
 740          */
 741         clear_IO_APIC();
 742 #endif
 743
 744 #ifdef CONFIG_SMP
 745         /*
 746          * Stop all of the others. Also disable the local irq to
 747          * not receive the per-cpu timer interrupt which may trigger
 748          * scheduler's load balance.
 749          */
 750         local_irq_disable();
 751         stop_other_cpus();
 752 #endif
 753
 754         lapic_shutdown();
 755         restore_boot_irq_mode();
 756
 757 #ifdef CONFIG_HPET_TIMER
 758         hpet_disable();
 759 #endif
 760
 761 #ifdef CONFIG_X86_64
 762         x86_platform.iommu_shutdown();
 763 #endif
 764
 765         if (kexec_in_progress)
 766                 x86_platform.guest.enc_kexec_finish();
 767 }
 768
 769 static void __machine_emergency_restart(int emergency)
 770 {
 771         reboot_emergency = emergency;
 772         machine_ops.emergency_restart();
 773 }
 774
 775 static void native_machine_restart(char *__unused)
 776 {
 777         pr_notice("machine restart\n");
 778
 779         if (!reboot_force)
 780                 machine_shutdown();
 781         __machine_emergency_restart(0);
 782 }
 783
 784 static void native_machine_halt(void)
 785 {
 786         /* Stop other cpus and apics */
 787         machine_shutdown();
 788
 789         tboot_shutdown(TB_SHUTDOWN_HALT);
 790
 791         stop_this_cpu(NULL);
 792 }
 793
 794 static void native_machine_power_off(void)
 795 {
 796         if (kernel_can_power_off()) {
 797                 if (!reboot_force)
 798                         machine_shutdown();
 799                 do_kernel_power_off();
 800         }
 801         /* A fallback in case there is no PM info available */
 802         tboot_shutdown(TB_SHUTDOWN_HALT);
 803 }
 804
 805 struct machine_ops machine_ops __ro_after_init = {
 806         .power_off = native_machine_power_off,
 807         .shutdown = native_machine_shutdown,
 808         .emergency_restart = native_machine_emergency_restart,
 809         .restart = native_machine_restart,
 810         .halt = native_machine_halt,
 811 #ifdef CONFIG_CRASH_DUMP
 812         .crash_shutdown = native_machine_crash_shutdown,
 813 #endif
 814 };
 815
 816 void machine_power_off(void)
 817 {
 818         machine_ops.power_off();
 819 }
 820
 821 void machine_shutdown(void)
 822 {
 823         machine_ops.shutdown();
 824 }
 825
 826 void machine_emergency_restart(void)
 827 {
 828         __machine_emergency_restart(1);
 829 }
 830
 831 void machine_restart(char *cmd)
 832 {
 833         machine_ops.restart(cmd);
 834 }
 835
 836 void machine_halt(void)
 837 {
 838         machine_ops.halt();
 839 }
 840
 841 #ifdef CONFIG_CRASH_DUMP
 842 void machine_crash_shutdown(struct pt_regs *regs)
 843 {
 844         machine_ops.crash_shutdown(regs);
 845 }
 846 #endif
 847
 848 /* This is the CPU performing the emergency shutdown work. */
 849 int crashing_cpu = -1;
 850
 851 #if defined(CONFIG_SMP)
 852
 853 static nmi_shootdown_cb shootdown_callback;
 854
 855 static atomic_t waiting_for_crash_ipi;
 856 static int crash_ipi_issued;
 857
 858 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 859 {
 860         int cpu;
 861
 862         cpu = raw_smp_processor_id();
 863
 864         /*
 865          * Don't do anything if this handler is invoked on crashing cpu.
 866          * Otherwise, system will completely hang. Crashing cpu can get
 867          * an NMI if system was initially booted with nmi_watchdog parameter.
 868          */
 869         if (cpu == crashing_cpu)
 870                 return NMI_HANDLED;
 871         local_irq_disable();
 872
 873         if (shootdown_callback)
 874                 shootdown_callback(cpu, regs);
 875
 876         /*
 877          * Prepare the CPU for reboot _after_ invoking the callback so that the
 878          * callback can safely use virtualization instructions, e.g. VMCLEAR.
 879          */
 880         cpu_emergency_disable_virtualization();
 881
 882         atomic_dec(&waiting_for_crash_ipi);
 883
 884         if (smp_ops.stop_this_cpu) {
 885                 smp_ops.stop_this_cpu();
 886                 unreachable();
 887         }
 888
 889         /* Assume hlt works */
 890         halt();
 891         for (;;)
 892                 cpu_relax();
 893
 894         return NMI_HANDLED;
 895 }
 896
 897 /**
 898  * nmi_shootdown_cpus - Stop other CPUs via NMI
 899  * @callback:   Optional callback to be invoked from the NMI handler
 900  *
 901  * The NMI handler on the remote CPUs invokes @callback, if not
 902  * NULL, first and then disables virtualization to ensure that
 903  * INIT is recognized during reboot.
 904  *
 905  * nmi_shootdown_cpus() can only be invoked once. After the first
 906  * invocation all other CPUs are stuck in crash_nmi_callback() and
 907  * cannot respond to a second NMI.
 908  */
 909 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 910 {
 911         unsigned long msecs;
 912
 913         local_irq_disable();
 914
 915         /*
 916          * Avoid certain doom if a shootdown already occurred; re-registering
 917          * the NMI handler will cause list corruption, modifying the callback
 918          * will do who knows what, etc...
 919          */
 920         if (WARN_ON_ONCE(crash_ipi_issued))
 921                 return;
 922
 923         /* Make a note of crashing cpu. Will be used in NMI callback. */
 924         crashing_cpu = safe_smp_processor_id();
 925
 926         shootdown_callback = callback;
 927
 928         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 929         /* Would it be better to replace the trap vector here? */
 930         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 931                                  NMI_FLAG_FIRST, "crash"))
 932                 return;         /* Return what? */
 933         /*
 934          * Ensure the new callback function is set before sending
 935          * out the NMI
 936          */
 937         wmb();
 938
 939         apic_send_IPI_allbutself(NMI_VECTOR);
 940
 941         /* Kick CPUs looping in NMI context. */
 942         WRITE_ONCE(crash_ipi_issued, 1);
 943
 944         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 945         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 946                 mdelay(1);
 947                 msecs--;
 948         }
 949
 950         /*
 951          * Leave the nmi callback set, shootdown is a one-time thing.  Clearing
 952          * the callback could result in a NULL pointer dereference if a CPU
 953          * (finally) responds after the timeout expires.
 954          */
 955 }
 956
 957 static inline void nmi_shootdown_cpus_on_restart(void)
 958 {
 959         if (!crash_ipi_issued)
 960                 nmi_shootdown_cpus(NULL);
 961 }
 962
 963 /*
 964  * Check if the crash dumping IPI got issued and if so, call its callback
 965  * directly. This function is used when we have already been in NMI handler.
 966  * It doesn't return.
 967  */
 968 void run_crash_ipi_callback(struct pt_regs *regs)
 969 {
 970         if (crash_ipi_issued)
 971                 crash_nmi_callback(0, regs);
 972 }
 973
 974 /* Override the weak function in kernel/panic.c */
 975 void __noreturn nmi_panic_self_stop(struct pt_regs *regs)
 976 {
 977         while (1) {
 978                 /* If no CPU is preparing crash dump, we simply loop here. */
 979                 run_crash_ipi_callback(regs);
 980                 cpu_relax();
 981         }
 982 }
 983
 984 #else /* !CONFIG_SMP */
 985 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 986 {
 987         /* No other CPUs to shoot down */
 988 }
 989
 990 static inline void nmi_shootdown_cpus_on_restart(void) { }
 991
 992 void run_crash_ipi_callback(struct pt_regs *regs)
 993 {
 994 }
 995 #endif