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 <linux/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 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",
 384                 .matches = {
 385                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 386                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 387                 },
 388         },
 389         {       /* Handle problems with rebooting on Dell 300's */
 390                 .callback = set_bios_reboot,
 391                 .ident = "Dell PowerEdge 300",
 392                 .matches = {
 393                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 394                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 395                 },
 396         },
 397         {       /* Handle problems with rebooting on Dell 1300's */
 398                 .callback = set_bios_reboot,
 399                 .ident = "Dell PowerEdge 1300",
 400                 .matches = {
 401                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 402                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 403                 },
 404         },
 405         {       /* Handle problems with rebooting on Dell 2400's */
 406                 .callback = set_bios_reboot,
 407                 .ident = "Dell PowerEdge 2400",
 408                 .matches = {
 409                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 410                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 411                 },
 412         },
 413         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
 414                 .callback = set_pci_reboot,
 415                 .ident = "Dell PowerEdge C6100",
 416                 .matches = {
 417                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
 418                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
 419                 },
 420         },
 421         {       /* Handle problems with rebooting on the Precision M6600. */
 422                 .callback = set_pci_reboot,
 423                 .ident = "Dell Precision M6600",
 424                 .matches = {
 425                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 426                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
 427                 },
 428         },
 429         {       /* Handle problems with rebooting on Dell T5400's */
 430                 .callback = set_bios_reboot,
 431                 .ident = "Dell Precision T5400",
 432                 .matches = {
 433                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 434                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
 435                 },
 436         },
 437         {       /* Handle problems with rebooting on Dell T7400's */
 438                 .callback = set_bios_reboot,
 439                 .ident = "Dell Precision T7400",
 440                 .matches = {
 441                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 442                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
 443                 },
 444         },
 445         {       /* Handle problems with rebooting on Dell XPS710 */
 446                 .callback = set_bios_reboot,
 447                 .ident = "Dell XPS710",
 448                 .matches = {
 449                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 450                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
 451                 },
 452         },
 453         {       /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
 454                 .callback = set_acpi_reboot,
 455                 .ident = "Dell OptiPlex 7450 AIO",
 456                 .matches = {
 457                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 458                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
 459                 },
 460         },
 461
 462         /* Hewlett-Packard */
 463         {       /* Handle problems with rebooting on HP laptops */
 464                 .callback = set_bios_reboot,
 465                 .ident = "HP Compaq Laptop",
 466                 .matches = {
 467                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 468                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 469                 },
 470         },
 471
 472         /* Sony */
 473         {       /* Handle problems with rebooting on Sony VGN-Z540N */
 474                 .callback = set_bios_reboot,
 475                 .ident = "Sony VGN-Z540N",
 476                 .matches = {
 477                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 478                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 479                 },
 480         },
 481
 482         { }
 483 };
 484
 485 static int __init reboot_init(void)
 486 {
 487         int rv;
 488
 489         /*
 490          * Only do the DMI check if reboot_type hasn't been overridden
 491          * on the command line
 492          */
 493         if (!reboot_default)
 494                 return 0;
 495
 496         /*
 497          * The DMI quirks table takes precedence. If no quirks entry
 498          * matches and the ACPI Hardware Reduced bit is set and EFI
 499          * runtime services are enabled, force EFI reboot.
 500          */
 501         rv = dmi_check_system(reboot_dmi_table);
 502
 503         if (!rv && efi_reboot_required() && !efi_runtime_disabled())
 504                 reboot_type = BOOT_EFI;
 505
 506         return 0;
 507 }
 508 core_initcall(reboot_init);
 509
 510 static inline void kb_wait(void)
 511 {
 512         int i;
 513
 514         for (i = 0; i < 0x10000; i++) {
 515                 if ((inb(0x64) & 0x02) == 0)
 516                         break;
 517                 udelay(2);
 518         }
 519 }
 520
 521 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
 522 {
 523         cpu_emergency_vmxoff();
 524 }
 525
 526 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
 527 static void emergency_vmx_disable_all(void)
 528 {
 529         /* Just make sure we won't change CPUs while doing this */
 530         local_irq_disable();
 531
 532         /*
 533          * We need to disable VMX on all CPUs before rebooting, otherwise
 534          * we risk hanging up the machine, because the CPU ignores INIT
 535          * signals when VMX is enabled.
 536          *
 537          * We can't take any locks and we may be on an inconsistent
 538          * state, so we use NMIs as IPIs to tell the other CPUs to disable
 539          * VMX and halt.
 540          *
 541          * For safety, we will avoid running the nmi_shootdown_cpus()
 542          * stuff unnecessarily, but we don't have a way to check
 543          * if other CPUs have VMX enabled. So we will call it only if the
 544          * CPU we are running on has VMX enabled.
 545          *
 546          * We will miss cases where VMX is not enabled on all CPUs. This
 547          * shouldn't do much harm because KVM always enable VMX on all
 548          * CPUs anyway. But we can miss it on the small window where KVM
 549          * is still enabling VMX.
 550          */
 551         if (cpu_has_vmx() && cpu_vmx_enabled()) {
 552                 /* Disable VMX on this CPU. */
 553                 cpu_vmxoff();
 554
 555                 /* Halt and disable VMX on the other CPUs */
 556                 nmi_shootdown_cpus(vmxoff_nmi);
 557
 558         }
 559 }
 560
 561
 562 void __attribute__((weak)) mach_reboot_fixups(void)
 563 {
 564 }
 565
 566 /*
 567  * To the best of our knowledge Windows compatible x86 hardware expects
 568  * the following on reboot:
 569  *
 570  * 1) If the FADT has the ACPI reboot register flag set, try it
 571  * 2) If still alive, write to the keyboard controller
 572  * 3) If still alive, write to the ACPI reboot register again
 573  * 4) If still alive, write to the keyboard controller again
 574  * 5) If still alive, call the EFI runtime service to reboot
 575  * 6) If no EFI runtime service, call the BIOS to do a reboot
 576  *
 577  * We default to following the same pattern. We also have
 578  * two other reboot methods: 'triple fault' and 'PCI', which
 579  * can be triggered via the reboot= kernel boot option or
 580  * via quirks.
 581  *
 582  * This means that this function can never return, it can misbehave
 583  * by not rebooting properly and hanging.
 584  */
 585 static void native_machine_emergency_restart(void)
 586 {
 587         int i;
 588         int attempt = 0;
 589         int orig_reboot_type = reboot_type;
 590         unsigned short mode;
 591
 592         if (reboot_emergency)
 593                 emergency_vmx_disable_all();
 594
 595         tboot_shutdown(TB_SHUTDOWN_REBOOT);
 596
 597         /* Tell the BIOS if we want cold or warm reboot */
 598         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 599         *((unsigned short *)__va(0x472)) = mode;
 600
 601         /*
 602          * If an EFI capsule has been registered with the firmware then
 603          * override the reboot= parameter.
 604          */
 605         if (efi_capsule_pending(NULL)) {
 606                 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
 607                 reboot_type = BOOT_EFI;
 608         }
 609
 610         for (;;) {
 611                 /* Could also try the reset bit in the Hammer NB */
 612                 switch (reboot_type) {
 613                 case BOOT_ACPI:
 614                         acpi_reboot();
 615                         reboot_type = BOOT_KBD;
 616                         break;
 617
 618                 case BOOT_KBD:
 619                         mach_reboot_fixups(); /* For board specific fixups */
 620
 621                         for (i = 0; i < 10; i++) {
 622                                 kb_wait();
 623                                 udelay(50);
 624                                 outb(0xfe, 0x64); /* Pulse reset low */
 625                                 udelay(50);
 626                         }
 627                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
 628                                 attempt = 1;
 629                                 reboot_type = BOOT_ACPI;
 630                         } else {
 631                                 reboot_type = BOOT_EFI;
 632                         }
 633                         break;
 634
 635                 case BOOT_EFI:
 636                         efi_reboot(reboot_mode, NULL);
 637                         reboot_type = BOOT_BIOS;
 638                         break;
 639
 640                 case BOOT_BIOS:
 641                         machine_real_restart(MRR_BIOS);
 642
 643                         /* We're probably dead after this, but... */
 644                         reboot_type = BOOT_CF9_SAFE;
 645                         break;
 646
 647                 case BOOT_CF9_FORCE:
 648                         port_cf9_safe = true;
 649                         /* Fall through */
 650
 651                 case BOOT_CF9_SAFE:
 652                         if (port_cf9_safe) {
 653                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
 654                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
 655                                 outb(cf9|2, 0xcf9); /* Request hard reset */
 656                                 udelay(50);
 657                                 /* Actually do the reset */
 658                                 outb(cf9|reboot_code, 0xcf9);
 659                                 udelay(50);
 660                         }
 661                         reboot_type = BOOT_TRIPLE;
 662                         break;
 663
 664                 case BOOT_TRIPLE:
 665                         idt_invalidate(NULL);
 666                         __asm__ __volatile__("int3");
 667
 668                         /* We're probably dead after this, but... */
 669                         reboot_type = BOOT_KBD;
 670                         break;
 671                 }
 672         }
 673 }
 674
 675 void native_machine_shutdown(void)
 676 {
 677         /* Stop the cpus and apics */
 678 #ifdef CONFIG_X86_IO_APIC
 679         /*
 680          * Disabling IO APIC before local APIC is a workaround for
 681          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
 682          * Specification Update". In this situation, interrupts that target
 683          * a Logical Processor whose Local APIC is either in the process of
 684          * being hardware disabled or software disabled are neither delivered
 685          * nor discarded. When this erratum occurs, the processor may hang.
 686          *
 687          * Even without the erratum, it still makes sense to quiet IO APIC
 688          * before disabling Local APIC.
 689          */
 690         clear_IO_APIC();
 691 #endif
 692
 693 #ifdef CONFIG_SMP
 694         /*
 695          * Stop all of the others. Also disable the local irq to
 696          * not receive the per-cpu timer interrupt which may trigger
 697          * scheduler's load balance.
 698          */
 699         local_irq_disable();
 700         stop_other_cpus();
 701 #endif
 702
 703         lapic_shutdown();
 704         restore_boot_irq_mode();
 705
 706 #ifdef CONFIG_HPET_TIMER
 707         hpet_disable();
 708 #endif
 709
 710 #ifdef CONFIG_X86_64
 711         x86_platform.iommu_shutdown();
 712 #endif
 713 }
 714
 715 static void __machine_emergency_restart(int emergency)
 716 {
 717         reboot_emergency = emergency;
 718         machine_ops.emergency_restart();
 719 }
 720
 721 static void native_machine_restart(char *__unused)
 722 {
 723         pr_notice("machine restart\n");
 724
 725         if (!reboot_force)
 726                 machine_shutdown();
 727         __machine_emergency_restart(0);
 728 }
 729
 730 static void native_machine_halt(void)
 731 {
 732         /* Stop other cpus and apics */
 733         machine_shutdown();
 734
 735         tboot_shutdown(TB_SHUTDOWN_HALT);
 736
 737         stop_this_cpu(NULL);
 738 }
 739
 740 static void native_machine_power_off(void)
 741 {
 742         if (pm_power_off) {
 743                 if (!reboot_force)
 744                         machine_shutdown();
 745                 pm_power_off();
 746         }
 747         /* A fallback in case there is no PM info available */
 748         tboot_shutdown(TB_SHUTDOWN_HALT);
 749 }
 750
 751 struct machine_ops machine_ops __ro_after_init = {
 752         .power_off = native_machine_power_off,
 753         .shutdown = native_machine_shutdown,
 754         .emergency_restart = native_machine_emergency_restart,
 755         .restart = native_machine_restart,
 756         .halt = native_machine_halt,
 757 #ifdef CONFIG_KEXEC_CORE
 758         .crash_shutdown = native_machine_crash_shutdown,
 759 #endif
 760 };
 761
 762 void machine_power_off(void)
 763 {
 764         machine_ops.power_off();
 765 }
 766
 767 void machine_shutdown(void)
 768 {
 769         machine_ops.shutdown();
 770 }
 771
 772 void machine_emergency_restart(void)
 773 {
 774         __machine_emergency_restart(1);
 775 }
 776
 777 void machine_restart(char *cmd)
 778 {
 779         machine_ops.restart(cmd);
 780 }
 781
 782 void machine_halt(void)
 783 {
 784         machine_ops.halt();
 785 }
 786
 787 #ifdef CONFIG_KEXEC_CORE
 788 void machine_crash_shutdown(struct pt_regs *regs)
 789 {
 790         machine_ops.crash_shutdown(regs);
 791 }
 792 #endif
 793
 794
 795 /* This is the CPU performing the emergency shutdown work. */
 796 int crashing_cpu = -1;
 797
 798 #if defined(CONFIG_SMP)
 799
 800 static nmi_shootdown_cb shootdown_callback;
 801
 802 static atomic_t waiting_for_crash_ipi;
 803 static int crash_ipi_issued;
 804
 805 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
 806 {
 807         int cpu;
 808
 809         cpu = raw_smp_processor_id();
 810
 811         /*
 812          * Don't do anything if this handler is invoked on crashing cpu.
 813          * Otherwise, system will completely hang. Crashing cpu can get
 814          * an NMI if system was initially booted with nmi_watchdog parameter.
 815          */
 816         if (cpu == crashing_cpu)
 817                 return NMI_HANDLED;
 818         local_irq_disable();
 819
 820         shootdown_callback(cpu, regs);
 821
 822         atomic_dec(&waiting_for_crash_ipi);
 823         /* Assume hlt works */
 824         halt();
 825         for (;;)
 826                 cpu_relax();
 827
 828         return NMI_HANDLED;
 829 }
 830
 831 /*
 832  * Halt all other CPUs, calling the specified function on each of them
 833  *
 834  * This function can be used to halt all other CPUs on crash
 835  * or emergency reboot time. The function passed as parameter
 836  * will be called inside a NMI handler on all CPUs.
 837  */
 838 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 839 {
 840         unsigned long msecs;
 841         local_irq_disable();
 842
 843         /* Make a note of crashing cpu. Will be used in NMI callback. */
 844         crashing_cpu = safe_smp_processor_id();
 845
 846         shootdown_callback = callback;
 847
 848         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 849         /* Would it be better to replace the trap vector here? */
 850         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
 851                                  NMI_FLAG_FIRST, "crash"))
 852                 return;         /* Return what? */
 853         /*
 854          * Ensure the new callback function is set before sending
 855          * out the NMI
 856          */
 857         wmb();
 858
 859         apic_send_IPI_allbutself(NMI_VECTOR);
 860
 861         /* Kick CPUs looping in NMI context. */
 862         WRITE_ONCE(crash_ipi_issued, 1);
 863
 864         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 865         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 866                 mdelay(1);
 867                 msecs--;
 868         }
 869
 870         /* Leave the nmi callback set */
 871 }
 872
 873 /*
 874  * Check if the crash dumping IPI got issued and if so, call its callback
 875  * directly. This function is used when we have already been in NMI handler.
 876  * It doesn't return.
 877  */
 878 void run_crash_ipi_callback(struct pt_regs *regs)
 879 {
 880         if (crash_ipi_issued)
 881                 crash_nmi_callback(0, regs);
 882 }
 883
 884 /* Override the weak function in kernel/panic.c */
 885 void nmi_panic_self_stop(struct pt_regs *regs)
 886 {
 887         while (1) {
 888                 /* If no CPU is preparing crash dump, we simply loop here. */
 889                 run_crash_ipi_callback(regs);
 890                 cpu_relax();
 891         }
 892 }
 893
 894 #else /* !CONFIG_SMP */
 895 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
 896 {
 897         /* No other CPUs to shoot down */
 898 }
 899
 900 void run_crash_ipi_callback(struct pt_regs *regs)
 901 {
 902 }
 903 #endif