root/arch/x86/kernel/reboot.c

DEFINITIONS

1. set_acpi_reboot
2. set_bios_reboot
3. set_efi_reboot
4. machine_real_restart
5. set_pci_reboot
6. set_kbd_reboot
7. reboot_init
8. kb_wait
9. vmxoff_nmi
10. emergency_vmx_disable_all
11. mach_reboot_fixups
12. native_machine_emergency_restart
13. native_machine_shutdown
14. __machine_emergency_restart
15. native_machine_restart
16. native_machine_halt
17. native_machine_power_off
18. machine_power_off
19. machine_shutdown
20. machine_emergency_restart
21. machine_restart
22. machine_halt
23. machine_crash_shutdown
24. crash_nmi_callback
25. nmi_shootdown_cpus
26. run_crash_ipi_callback
27. nmi_panic_self_stop
28. nmi_shootdown_cpus
29. run_crash_ipi_callback

   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 /*
  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 back to the initial page table.
 117          */
 118 #ifdef CONFIG_X86_32
 119         load_cr3(initial_page_table);
 120 #else
 121         write_cr3(real_mode_header->trampoline_pgd);
 122 
 123         /* Exiting long mode will fail if CR4.PCIDE is set. */
 124         if (boot_cpu_has(X86_FEATURE_PCID))
 125                 cr4_clear_bits(X86_CR4_PCIDE);
 126 #endif
 127 
 128         /* Jump to the identity-mapped low memory code */
 129 #ifdef CONFIG_X86_32
 130         asm volatile("jmpl *%0" : :
 131                      "rm" (real_mode_header->machine_real_restart_asm),
 132                      "a" (type));
 133 #else
 134         asm volatile("ljmpl *%0" : :
 135                      "m" (real_mode_header->machine_real_restart_asm),
 136                      "D" (type));
 137 #endif
 138         unreachable();
 139 }
 140 #ifdef CONFIG_APM_MODULE
 141 EXPORT_SYMBOL(machine_real_restart);
 142 #endif
 143 STACK_FRAME_NON_STANDARD(machine_real_restart);
 144 
 145 /*
 146  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 147  */
 148 static int __init set_pci_reboot(const struct dmi_system_id *d)
 149 {
 150         if (reboot_type != BOOT_CF9_FORCE) {
 151                 reboot_type = BOOT_CF9_FORCE;
 152                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 153                         d->ident, "PCI");
 154         }
 155         return 0;
 156 }
 157 
 158 static int __init set_kbd_reboot(const struct dmi_system_id *d)
 159 {
 160         if (reboot_type != BOOT_KBD) {
 161                 reboot_type = BOOT_KBD;
 162                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
 163                         d->ident, "KBD");
 164         }
 165         return 0;
 166 }
 167 
 168 /*
 169  * This is a single dmi_table handling all reboot quirks.
 170  */
 171 static const struct dmi_system_id reboot_dmi_table[] __initconst = {
 172 
 173         /* Acer */
 174         {       /* Handle reboot issue on Acer Aspire one */
 175                 .callback = set_kbd_reboot,
 176                 .ident = "Acer Aspire One A110",
 177                 .matches = {
 178                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 179                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 180                 },
 181         },
 182         {       /* Handle reboot issue on Acer TravelMate X514-51T */
 183                 .callback = set_efi_reboot,
 184                 .ident = "Acer TravelMate X514-51T",
 185                 .matches = {
 186                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 187                         DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate X514-51T"),
 188                 },
 189         },
 190 
 191         /* Apple */
 192         {       /* Handle problems with rebooting on Apple MacBook5 */
 193                 .callback = set_pci_reboot,
 194                 .ident = "Apple MacBook5",
 195                 .matches = {
 196                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 197                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
 198                 },
 199         },
 200         {       /* Handle problems with rebooting on Apple MacBook6,1 */
 201                 .callback = set_pci_reboot,
 202                 .ident = "Apple MacBook6,1",
 203                 .matches = {
 204                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 205                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook6,1"),
 206                 },
 207         },
 208         {       /* Handle problems with rebooting on Apple MacBookPro5 */
 209                 .callback = set_pci_reboot,
 210                 .ident = "Apple MacBookPro5",
 211                 .matches = {
 212                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 213                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
 214                 },
 215         },
 216         {       /* Handle problems with rebooting on Apple Macmini3,1 */
 217                 .callback = set_pci_reboot,
 218                 .ident = "Apple Macmini3,1",
 219                 .matches = {
 220                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 221                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
 222                 },
 223         },
 224         {       /* Handle problems with rebooting on the iMac9,1. */
 225                 .callback = set_pci_reboot,
 226                 .ident = "Apple iMac9,1",
 227                 .matches = {
 228                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 229                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
 230                 },
 231         },
 232         {       /* Handle problems with rebooting on the iMac10,1. */
 233                 .callback = set_pci_reboot,
 234                 .ident = "Apple iMac10,1",
 235                 .matches = {
 236                     DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 237                     DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
 238                 },
 239         },
 240 
 241         /* ASRock */
 242         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
 243                 .callback = set_pci_reboot,
 244                 .ident = "ASRock Q1900DC-ITX",
 245                 .matches = {
 246                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
 247                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
 248                 },
 249         },
 250 
 251         /* ASUS */
 252         {       /* Handle problems with rebooting on ASUS P4S800 */
 253                 .callback = set_bios_reboot,
 254                 .ident = "ASUS P4S800",
 255                 .matches = {
 256                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
 257                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
 258                 },
 259         },
 260         {       /* Handle problems with rebooting on ASUS EeeBook X205TA */
 261                 .callback = set_acpi_reboot,
 262                 .ident = "ASUS EeeBook X205TA",
 263                 .matches = {
 264                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 265                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
 266                 },
 267         },
 268         {       /* Handle problems with rebooting on ASUS EeeBook X205TAW */
 269                 .callback = set_acpi_reboot,
 270                 .ident = "ASUS EeeBook X205TAW",
 271                 .matches = {
 272                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 273                         DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
 274                 },
 275         },
 276 
 277         /* Certec */
 278         {       /* Handle problems with rebooting on Certec BPC600 */
 279                 .callback = set_pci_reboot,
 280                 .ident = "Certec BPC600",
 281                 .matches = {
 282                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
 283                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
 284                 },
 285         },
 286 
 287         /* Dell */
 288         {       /* Handle problems with rebooting on Dell DXP061 */
 289                 .callback = set_bios_reboot,
 290                 .ident = "Dell DXP061",
 291                 .matches = {
 292                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 293                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
 294                 },
 295         },
 296         {       /* Handle problems with rebooting on Dell E520's */
 297                 .callback = set_bios_reboot,
 298                 .ident = "Dell E520",
 299                 .matches = {
 300                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 301                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 302                 },
 303         },
 304         {       /* Handle problems with rebooting on the Latitude E5410. */
 305                 .callback = set_pci_reboot,
 306                 .ident = "Dell Latitude E5410",
 307                 .matches = {
 308                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 309                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
 310                 },
 311         },
 312         {       /* Handle problems with rebooting on the Latitude E5420. */
 313                 .callback = set_pci_reboot,
 314                 .ident = "Dell Latitude E5420",
 315                 .matches = {
 316                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 317                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
 318                 },
 319         },
 320         {       /* Handle problems with rebooting on the Latitude E6320. */
 321                 .callback = set_pci_reboot,
 322                 .ident = "Dell Latitude E6320",
 323                 .matches = {
 324                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 325                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
 326                 },
 327         },
 328         {       /* Handle problems with rebooting on the Latitude E6420. */
 329                 .callback = set_pci_reboot,
 330                 .ident = "Dell Latitude E6420",
 331                 .matches = {
 332                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 333                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
 334                 },
 335         },
 336         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
 337                 .callback = set_bios_reboot,
 338                 .ident = "Dell OptiPlex 330",
 339                 .matches = {
 340                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 341                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
 342                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
 343                 },
 344         },
 345         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
 346                 .callback = set_bios_reboot,
 347                 .ident = "Dell OptiPlex 360",
 348                 .matches = {
 349                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 350                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
 351                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
 352                 },
 353         },
 354         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
 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                 },
 361         },
 362         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
 363                 .callback = set_bios_reboot,
 364                 .ident = "Dell OptiPlex 745",
 365                 .matches = {
 366                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 367                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 368                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
 369                 },
 370         },
 371         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
 372                 .callback = set_bios_reboot,
 373                 .ident = "Dell OptiPlex 745",
 374                 .matches = {
 375                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 376                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 377                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
 378                 },
 379         },
 380         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
 381                 .callback = set_bios_reboot,
 382                 .ident = "Dell OptiPlex 760",
 383                 .matches = {
 384                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 385                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
 386                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
 387                 },
 388         },
 389         {       /* Handle problems with rebooting on the OptiPlex 990. */
 390                 .callback = set_pci_reboot,
 391                 .ident = "Dell OptiPlex 990",
 392                 .matches = {
 393                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 394                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 395                 },
 396         },
 397         {       /* Handle problems with rebooting on Dell 300's */
 398                 .callback = set_bios_reboot,
 399                 .ident = "Dell PowerEdge 300",
 400                 .matches = {
 401                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 402                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 403                 },
 404         },
 405         {       /* Handle problems with rebooting on Dell 1300's */
 406                 .callback = set_bios_reboot,
 407                 .ident = "Dell PowerEdge 1300",
 408                 .matches = {
 409                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 410                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 411                 },
 412         },
 413         {       /* Handle problems with rebooting on Dell 2400's */
 414                 .callback = set_bios_reboot,
 415                 .ident = "Dell PowerEdge 2400",
 416                 .matches = {
 417                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 418                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 419                 },
 420         },
 421         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 422                 .callback = set_pci_reboot,
 423                 .ident = "Dell PowerEdge C6100",
 424                 .matches = {
 425                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 426                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 427                 },
 428         },
 429         {       /* Handle problems with rebooting on the Precision M6600. */
 430                 .callback = set_pci_reboot,
 431                 .ident = "Dell Precision M6600",
 432                 .matches = {
 433                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 434                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 435                 },
 436         },
 437         {       /* Handle problems with rebooting on Dell T5400's */
 438                 .callback = set_bios_reboot,
 439                 .ident = "Dell Precision T5400",
 440                 .matches = {
 441                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 442                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 443                 },
 444         },
 445         {       /* Handle problems with rebooting on Dell T7400's */
 446                 .callback = set_bios_reboot,
 447                 .ident = "Dell Precision T7400",
 448                 .matches = {
 449                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 450                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 451                 },
 452         },
 453         {       /* Handle problems with rebooting on Dell XPS710 */
 454                 .callback = set_bios_reboot,
 455                 .ident = "Dell XPS710",
 456                 .matches = {
 457                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 458                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 459                 },
 460         },
 461         {       /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
 462                 .callback = set_acpi_reboot,
 463                 .ident = "Dell OptiPlex 7450 AIO",
 464                 .matches = {
 465                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 466                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
 467                 },
 468         },
 469 
 470         /* Hewlett-Packard */
 471         {       /* Handle problems with rebooting on HP laptops */
 472                 .callback = set_bios_reboot,
 473                 .ident = "HP Compaq Laptop",
 474                 .matches = {
 475                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 476                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 477                 },
 478         },
 479 
 480         /* Sony */
 481         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 482                 .callback = set_bios_reboot,
 483                 .ident = "Sony VGN-Z540N",
 484                 .matches = {
 485                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 486                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 487                 },
 488         },
 489 
 490         { }
 491 };
 492 
 493 static int __init reboot_init(void)
 494 {
 495         int rv;
 496 
 497         /*
 498          * Only do the DMI check if reboot_type hasn't been overridden
 499          * on the command line
 500          */
 501         if (!reboot_default)
 502                 return 0;
 503 
 504         /*
 505          * The DMI quirks table takes precedence. If no quirks entry
 506          * matches and the ACPI Hardware Reduced bit is set and EFI
 507          * runtime services are enabled, force EFI reboot.
 508          */
 509         rv = dmi_check_system(reboot_dmi_table);
 510 
 511         if (!rv && efi_reboot_required() && !efi_runtime_disabled())
 512                 reboot_type = BOOT_EFI;
 513 
 514         return 0;
 515 }
 516 core_initcall(reboot_init);
 517 
 518 static inline void kb_wait(void)
 519 {
 520         int i;
 521 
 522         for (i = 0; i < 0x10000; i++) {
 523                 if ((inb(0x64) & 0x02) == 0)
 524                         break;
 525                 udelay(2);
 526         }
 527 }
 528 
 529 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 530 {
 531         cpu_emergency_vmxoff();
 532 }
 533 
 534 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 535 static void emergency_vmx_disable_all(void)
 536 {
 537         /* Just make sure we won't change CPUs while doing this */
 538         local_irq_disable();
 539 
 540         /*
 541          * We need to disable VMX on all CPUs before rebooting, otherwise
 542          * we risk hanging up the machine, because the CPU ignore INIT
 543          * signals when VMX is enabled.
 544          *
 545          * We can't take any locks and we may be on an inconsistent
 546          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 547          * VMX and halt.
 548          *
 549          * For safety, we will avoid running the nmi_shootdown_cpus()
 550          * stuff unnecessarily, but we don't have a way to check
 551          * if other CPUs have VMX enabled. So we will call it only if the
 552          * CPU we are running on has VMX enabled.
 553          *
 554          * We will miss cases where VMX is not enabled on all CPUs. This
 555          * shouldn't do much harm because KVM always enable VMX on all
 556          * CPUs anyway. But we can miss it on the small window where KVM
 557          * is still enabling VMX.
 558          */
 559         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 560                 /* Disable VMX on this CPU. */
 561                 cpu_vmxoff();
 562 
 563                 /* Halt and disable VMX on the other CPUs */
 564                 nmi_shootdown_cpus(vmxoff_nmi);
 565 
 566         }
 567 }
 568 
 569 
 570 void __attribute__((weak)) mach_reboot_fixups(void)
 571 {
 572 }
 573 
 574 /*
 575  * To the best of our knowledge Windows compatible x86 hardware expects
 576  * the following on reboot:
 577  *
 578  * 1) If the FADT has the ACPI reboot register flag set, try it
 579  * 2) If still alive, write to the keyboard controller
 580  * 3) If still alive, write to the ACPI reboot register again
 581  * 4) If still alive, write to the keyboard controller again
 582  * 5) If still alive, call the EFI runtime service to reboot
 583  * 6) If no EFI runtime service, call the BIOS to do a reboot
 584  *
 585  * We default to following the same pattern. We also have
 586  * two other reboot methods: 'triple fault' and 'PCI', which
 587  * can be triggered via the reboot= kernel boot option or
 588  * via quirks.
 589  *
 590  * This means that this function can never return, it can misbehave
 591  * by not rebooting properly and hanging.
 592  */
 593 static void native_machine_emergency_restart(void)
 594 {
 595         int i;
 596         int attempt = 0;
 597         int orig_reboot_type = reboot_type;
 598         unsigned short mode;
 599 
 600         if (reboot_emergency)
 601                 emergency_vmx_disable_all();
 602 
 603         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 604 
 605         /* Tell the BIOS if we want cold or warm reboot */
 606         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 607         *((unsigned short *)__va(0x472)) = mode;
 608 
 609         /*
 610          * If an EFI capsule has been registered with the firmware then
 611          * override the reboot= parameter.
 612          */
 613         if (efi_capsule_pending(NULL)) {
 614                 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
 615                 reboot_type = BOOT_EFI;
 616         }
 617 
 618         for (;;) {
 619                 /* Could also try the reset bit in the Hammer NB */
 620                 switch (reboot_type) {
 621                 case BOOT_ACPI:
 622                         acpi_reboot();
 623                         reboot_type = BOOT_KBD;
 624                         break;
 625 
 626                 case BOOT_KBD:
 627                         mach_reboot_fixups(); /* For board specific fixups */
 628 
 629                         for (i = 0; i < 10; i++) {
 630                                 kb_wait();
 631                                 udelay(50);
 632                                 outb(0xfe, 0x64); /* Pulse reset low */
 633                                 udelay(50);
 634                         }
 635                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 636                                 attempt = 1;
 637                                 reboot_type = BOOT_ACPI;
 638                         } else {
 639                                 reboot_type = BOOT_EFI;
 640                         }
 641                         break;
 642 
 643                 case BOOT_EFI:
 644                         efi_reboot(reboot_mode, NULL);
 645                         reboot_type = BOOT_BIOS;
 646                         break;
 647 
 648                 case BOOT_BIOS:
 649                         machine_real_restart(MRR_BIOS);
 650 
 651                         /* We're probably dead after this, but... */
 652                         reboot_type = BOOT_CF9_SAFE;
 653                         break;
 654 
 655                 case BOOT_CF9_FORCE:
 656                         port_cf9_safe = true;
 657                         /* Fall through */
 658 
 659                 case BOOT_CF9_SAFE:
 660                         if (port_cf9_safe) {
 661                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 662                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 663                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 664                                 udelay(50);
 665                                 /* Actually do the reset */
 666                                 outb(cf9|reboot_code, 0xcf9);
 667                                 udelay(50);
 668                         }
 669                         reboot_type = BOOT_TRIPLE;
 670                         break;
 671 
 672                 case BOOT_TRIPLE:
 673                         idt_invalidate(NULL);
 674                         __asm__ __volatile__("int3");
 675 
 676                         /* We're probably dead after this, but... */
 677                         reboot_type = BOOT_KBD;
 678                         break;
 679                 }
 680         }
 681 }
 682 
 683 void native_machine_shutdown(void)
 684 {
 685         /* Stop the cpus and apics */
 686 #ifdef CONFIG_X86_IO_APIC
 687         /*
 688          * Disabling IO APIC before local APIC is a workaround for
 689          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 690          * Specification Update". In this situation, interrupts that target
 691          * a Logical Processor whose Local APIC is either in the process of
 692          * being hardware disabled or software disabled are neither delivered
 693          * nor discarded. When this erratum occurs, the processor may hang.
 694          *
 695          * Even without the erratum, it still makes sense to quiet IO APIC
 696          * before disabling Local APIC.
 697          */
 698         clear_IO_APIC();
 699 #endif
 700 
 701 #ifdef CONFIG_SMP
 702         /*
 703          * Stop all of the others. Also disable the local irq to
 704          * not receive the per-cpu timer interrupt which may trigger
 705          * scheduler's load balance.
 706          */
 707         local_irq_disable();
 708         stop_other_cpus();
 709 #endif
 710 
 711         lapic_shutdown();
 712         restore_boot_irq_mode();
 713 
 714 #ifdef CONFIG_HPET_TIMER
 715         hpet_disable();
 716 #endif
 717 
 718 #ifdef CONFIG_X86_64
 719         x86_platform.iommu_shutdown();
 720 #endif
 721 }
 722 
 723 static void __machine_emergency_restart(int emergency)
 724 {
 725         reboot_emergency = emergency;
 726         machine_ops.emergency_restart();
 727 }
 728 
 729 static void native_machine_restart(char *__unused)
 730 {
 731         pr_notice("machine restart\n");
 732 
 733         if (!reboot_force)
 734                 machine_shutdown();
 735         __machine_emergency_restart(0);
 736 }
 737 
 738 static void native_machine_halt(void)
 739 {
 740         /* Stop other cpus and apics */
 741         machine_shutdown();
 742 
 743         tboot_shutdown(TB_SHUTDOWN_HALT);
 744 
 745         stop_this_cpu(NULL);
 746 }
 747 
 748 static void native_machine_power_off(void)
 749 {
 750         if (pm_power_off) {
 751                 if (!reboot_force)
 752                         machine_shutdown();
 753                 pm_power_off();
 754         }
 755         /* A fallback in case there is no PM info available */
 756         tboot_shutdown(TB_SHUTDOWN_HALT);
 757 }
 758 
 759 struct machine_ops machine_ops __ro_after_init = {
 760         .power_off = native_machine_power_off,
 761         .shutdown = native_machine_shutdown,
 762         .emergency_restart = native_machine_emergency_restart,
 763         .restart = native_machine_restart,
 764         .halt = native_machine_halt,
 765 #ifdef CONFIG_KEXEC_CORE
 766         .crash_shutdown = native_machine_crash_shutdown,
 767 #endif
 768 };
 769 
 770 void machine_power_off(void)
 771 {
 772         machine_ops.power_off();
 773 }
 774 
 775 void machine_shutdown(void)
 776 {
 777         machine_ops.shutdown();
 778 }
 779 
 780 void machine_emergency_restart(void)
 781 {
 782         __machine_emergency_restart(1);
 783 }
 784 
 785 void machine_restart(char *cmd)
 786 {
 787         machine_ops.restart(cmd);
 788 }
 789 
 790 void machine_halt(void)
 791 {
 792         machine_ops.halt();
 793 }
 794 
 795 #ifdef CONFIG_KEXEC_CORE
 796 void machine_crash_shutdown(struct pt_regs *regs)
 797 {
 798         machine_ops.crash_shutdown(regs);
 799 }
 800 #endif
 801 
 802 
 803 /* This is the CPU performing the emergency shutdown work. */
 804 int crashing_cpu = -1;
 805 
 806 #if defined(CONFIG_SMP)
 807 
 808 static nmi_shootdown_cb shootdown_callback;
 809 
 810 static atomic_t waiting_for_crash_ipi;
 811 static int crash_ipi_issued;
 812 
 813 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 814 {
 815         int cpu;
 816 
 817         cpu = raw_smp_processor_id();
 818 
 819         /*
 820          * Don't do anything if this handler is invoked on crashing cpu.
 821          * Otherwise, system will completely hang. Crashing cpu can get
 822          * an NMI if system was initially booted with nmi_watchdog parameter.
 823          */
 824         if (cpu == crashing_cpu)
 825                 return NMI_HANDLED;
 826         local_irq_disable();
 827 
 828         shootdown_callback(cpu, regs);
 829 
 830         atomic_dec(&waiting_for_crash_ipi);
 831         /* Assume hlt works */
 832         halt();
 833         for (;;)
 834                 cpu_relax();
 835 
 836         return NMI_HANDLED;
 837 }
 838 
 839 /*
 840  * Halt all other CPUs, calling the specified function on each of them
 841  *
 842  * This function can be used to halt all other CPUs on crash
 843  * or emergency reboot time. The function passed as parameter
 844  * will be called inside a NMI handler on all CPUs.
 845  */
 846 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 847 {
 848         unsigned long msecs;
 849         local_irq_disable();
 850 
 851         /* Make a note of crashing cpu. Will be used in NMI callback. */
 852         crashing_cpu = safe_smp_processor_id();
 853 
 854         shootdown_callback = callback;
 855 
 856         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 857         /* Would it be better to replace the trap vector here? */
 858         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 859                                  NMI_FLAG_FIRST, "crash"))
 860                 return;         /* Return what? */
 861         /*
 862          * Ensure the new callback function is set before sending
 863          * out the NMI
 864          */
 865         wmb();
 866 
 867         apic_send_IPI_allbutself(NMI_VECTOR);
 868 
 869         /* Kick CPUs looping in NMI context. */
 870         WRITE_ONCE(crash_ipi_issued, 1);
 871 
 872         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 873         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 874                 mdelay(1);
 875                 msecs--;
 876         }
 877 
 878         /* Leave the nmi callback set */
 879 }
 880 
 881 /*
 882  * Check if the crash dumping IPI got issued and if so, call its callback
 883  * directly. This function is used when we have already been in NMI handler.
 884  * It doesn't return.
 885  */
 886 void run_crash_ipi_callback(struct pt_regs *regs)
 887 {
 888         if (crash_ipi_issued)
 889                 crash_nmi_callback(0, regs);
 890 }
 891 
 892 /* Override the weak function in kernel/panic.c */
 893 void nmi_panic_self_stop(struct pt_regs *regs)
 894 {
 895         while (1) {
 896                 /* If no CPU is preparing crash dump, we simply loop here. */
 897                 run_crash_ipi_callback(regs);
 898                 cpu_relax();
 899         }
 900 }
 901 
 902 #else /* !CONFIG_SMP */
 903 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 904 {
 905         /* No other CPUs to shoot down */
 906 }
 907 
 908 void run_crash_ipi_callback(struct pt_regs *regs)
 909 {
 910 }
 911 #endif