root/arch/x86/platform/efi/quirks.c

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DEFINITIONS

This source file includes following definitions.
  1. setup_storage_paranoia
  2. efi_delete_dummy_variable
  3. query_variable_store_nonblocking
  4. efi_query_variable_store
  5. efi_arch_mem_reserve
  6. can_free_region
  7. efi_reserve_boot_services
  8. efi_unmap_pages
  9. efi_free_boot_services
  10. efi_reuse_config
  11. efi_apply_memmap_quirks
  12. efi_reboot_required
  13. efi_poweroff_required
  14. qrk_capsule_setup_info
  15. efi_capsule_setup_info
  16. efi_recover_from_page_fault

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #define pr_fmt(fmt) "efi: " fmt
   3 
   4 #include <linux/init.h>
   5 #include <linux/kernel.h>
   6 #include <linux/string.h>
   7 #include <linux/time.h>
   8 #include <linux/types.h>
   9 #include <linux/efi.h>
  10 #include <linux/slab.h>
  11 #include <linux/memblock.h>
  12 #include <linux/acpi.h>
  13 #include <linux/dmi.h>
  14 
  15 #include <asm/e820/api.h>
  16 #include <asm/efi.h>
  17 #include <asm/uv/uv.h>
  18 #include <asm/cpu_device_id.h>
  19 #include <asm/reboot.h>
  20 
  21 #define EFI_MIN_RESERVE 5120
  22 
  23 #define EFI_DUMMY_GUID \
  24         EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
  25 
  26 #define QUARK_CSH_SIGNATURE             0x5f435348      /* _CSH */
  27 #define QUARK_SECURITY_HEADER_SIZE      0x400
  28 
  29 /*
  30  * Header prepended to the standard EFI capsule on Quark systems the are based
  31  * on Intel firmware BSP.
  32  * @csh_signature:      Unique identifier to sanity check signed module
  33  *                      presence ("_CSH").
  34  * @version:            Current version of CSH used. Should be one for Quark A0.
  35  * @modulesize:         Size of the entire module including the module header
  36  *                      and payload.
  37  * @security_version_number_index: Index of SVN to use for validation of signed
  38  *                      module.
  39  * @security_version_number: Used to prevent against roll back of modules.
  40  * @rsvd_module_id:     Currently unused for Clanton (Quark).
  41  * @rsvd_module_vendor: Vendor Identifier. For Intel products value is
  42  *                      0x00008086.
  43  * @rsvd_date:          BCD representation of build date as yyyymmdd, where
  44  *                      yyyy=4 digit year, mm=1-12, dd=1-31.
  45  * @headersize:         Total length of the header including including any
  46  *                      padding optionally added by the signing tool.
  47  * @hash_algo:          What Hash is used in the module signing.
  48  * @cryp_algo:          What Crypto is used in the module signing.
  49  * @keysize:            Total length of the key data including including any
  50  *                      padding optionally added by the signing tool.
  51  * @signaturesize:      Total length of the signature including including any
  52  *                      padding optionally added by the signing tool.
  53  * @rsvd_next_header:   32-bit pointer to the next Secure Boot Module in the
  54  *                      chain, if there is a next header.
  55  * @rsvd:               Reserved, padding structure to required size.
  56  *
  57  * See also QuartSecurityHeader_t in
  58  * Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h
  59  * from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP
  60  */
  61 struct quark_security_header {
  62         u32 csh_signature;
  63         u32 version;
  64         u32 modulesize;
  65         u32 security_version_number_index;
  66         u32 security_version_number;
  67         u32 rsvd_module_id;
  68         u32 rsvd_module_vendor;
  69         u32 rsvd_date;
  70         u32 headersize;
  71         u32 hash_algo;
  72         u32 cryp_algo;
  73         u32 keysize;
  74         u32 signaturesize;
  75         u32 rsvd_next_header;
  76         u32 rsvd[2];
  77 };
  78 
  79 static const efi_char16_t efi_dummy_name[] = L"DUMMY";
  80 
  81 static bool efi_no_storage_paranoia;
  82 
  83 /*
  84  * Some firmware implementations refuse to boot if there's insufficient
  85  * space in the variable store. The implementation of garbage collection
  86  * in some FW versions causes stale (deleted) variables to take up space
  87  * longer than intended and space is only freed once the store becomes
  88  * almost completely full.
  89  *
  90  * Enabling this option disables the space checks in
  91  * efi_query_variable_store() and forces garbage collection.
  92  *
  93  * Only enable this option if deleting EFI variables does not free up
  94  * space in your variable store, e.g. if despite deleting variables
  95  * you're unable to create new ones.
  96  */
  97 static int __init setup_storage_paranoia(char *arg)
  98 {
  99         efi_no_storage_paranoia = true;
 100         return 0;
 101 }
 102 early_param("efi_no_storage_paranoia", setup_storage_paranoia);
 103 
 104 /*
 105  * Deleting the dummy variable which kicks off garbage collection
 106 */
 107 void efi_delete_dummy_variable(void)
 108 {
 109         efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name,
 110                                      &EFI_DUMMY_GUID,
 111                                      EFI_VARIABLE_NON_VOLATILE |
 112                                      EFI_VARIABLE_BOOTSERVICE_ACCESS |
 113                                      EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL);
 114 }
 115 
 116 /*
 117  * In the nonblocking case we do not attempt to perform garbage
 118  * collection if we do not have enough free space. Rather, we do the
 119  * bare minimum check and give up immediately if the available space
 120  * is below EFI_MIN_RESERVE.
 121  *
 122  * This function is intended to be small and simple because it is
 123  * invoked from crash handler paths.
 124  */
 125 static efi_status_t
 126 query_variable_store_nonblocking(u32 attributes, unsigned long size)
 127 {
 128         efi_status_t status;
 129         u64 storage_size, remaining_size, max_size;
 130 
 131         status = efi.query_variable_info_nonblocking(attributes, &storage_size,
 132                                                      &remaining_size,
 133                                                      &max_size);
 134         if (status != EFI_SUCCESS)
 135                 return status;
 136 
 137         if (remaining_size - size < EFI_MIN_RESERVE)
 138                 return EFI_OUT_OF_RESOURCES;
 139 
 140         return EFI_SUCCESS;
 141 }
 142 
 143 /*
 144  * Some firmware implementations refuse to boot if there's insufficient space
 145  * in the variable store. Ensure that we never use more than a safe limit.
 146  *
 147  * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
 148  * store.
 149  */
 150 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
 151                                       bool nonblocking)
 152 {
 153         efi_status_t status;
 154         u64 storage_size, remaining_size, max_size;
 155 
 156         if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
 157                 return 0;
 158 
 159         if (nonblocking)
 160                 return query_variable_store_nonblocking(attributes, size);
 161 
 162         status = efi.query_variable_info(attributes, &storage_size,
 163                                          &remaining_size, &max_size);
 164         if (status != EFI_SUCCESS)
 165                 return status;
 166 
 167         /*
 168          * We account for that by refusing the write if permitting it would
 169          * reduce the available space to under 5KB. This figure was provided by
 170          * Samsung, so should be safe.
 171          */
 172         if ((remaining_size - size < EFI_MIN_RESERVE) &&
 173                 !efi_no_storage_paranoia) {
 174 
 175                 /*
 176                  * Triggering garbage collection may require that the firmware
 177                  * generate a real EFI_OUT_OF_RESOURCES error. We can force
 178                  * that by attempting to use more space than is available.
 179                  */
 180                 unsigned long dummy_size = remaining_size + 1024;
 181                 void *dummy = kzalloc(dummy_size, GFP_KERNEL);
 182 
 183                 if (!dummy)
 184                         return EFI_OUT_OF_RESOURCES;
 185 
 186                 status = efi.set_variable((efi_char16_t *)efi_dummy_name,
 187                                           &EFI_DUMMY_GUID,
 188                                           EFI_VARIABLE_NON_VOLATILE |
 189                                           EFI_VARIABLE_BOOTSERVICE_ACCESS |
 190                                           EFI_VARIABLE_RUNTIME_ACCESS,
 191                                           dummy_size, dummy);
 192 
 193                 if (status == EFI_SUCCESS) {
 194                         /*
 195                          * This should have failed, so if it didn't make sure
 196                          * that we delete it...
 197                          */
 198                         efi_delete_dummy_variable();
 199                 }
 200 
 201                 kfree(dummy);
 202 
 203                 /*
 204                  * The runtime code may now have triggered a garbage collection
 205                  * run, so check the variable info again
 206                  */
 207                 status = efi.query_variable_info(attributes, &storage_size,
 208                                                  &remaining_size, &max_size);
 209 
 210                 if (status != EFI_SUCCESS)
 211                         return status;
 212 
 213                 /*
 214                  * There still isn't enough room, so return an error
 215                  */
 216                 if (remaining_size - size < EFI_MIN_RESERVE)
 217                         return EFI_OUT_OF_RESOURCES;
 218         }
 219 
 220         return EFI_SUCCESS;
 221 }
 222 EXPORT_SYMBOL_GPL(efi_query_variable_store);
 223 
 224 /*
 225  * The UEFI specification makes it clear that the operating system is
 226  * free to do whatever it wants with boot services code after
 227  * ExitBootServices() has been called. Ignoring this recommendation a
 228  * significant bunch of EFI implementations continue calling into boot
 229  * services code (SetVirtualAddressMap). In order to work around such
 230  * buggy implementations we reserve boot services region during EFI
 231  * init and make sure it stays executable. Then, after
 232  * SetVirtualAddressMap(), it is discarded.
 233  *
 234  * However, some boot services regions contain data that is required
 235  * by drivers, so we need to track which memory ranges can never be
 236  * freed. This is done by tagging those regions with the
 237  * EFI_MEMORY_RUNTIME attribute.
 238  *
 239  * Any driver that wants to mark a region as reserved must use
 240  * efi_mem_reserve() which will insert a new EFI memory descriptor
 241  * into efi.memmap (splitting existing regions if necessary) and tag
 242  * it with EFI_MEMORY_RUNTIME.
 243  */
 244 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
 245 {
 246         phys_addr_t new_phys, new_size;
 247         struct efi_mem_range mr;
 248         efi_memory_desc_t md;
 249         int num_entries;
 250         void *new;
 251 
 252         if (efi_mem_desc_lookup(addr, &md) ||
 253             md.type != EFI_BOOT_SERVICES_DATA) {
 254                 pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
 255                 return;
 256         }
 257 
 258         if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
 259                 pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
 260                 return;
 261         }
 262 
 263         size += addr % EFI_PAGE_SIZE;
 264         size = round_up(size, EFI_PAGE_SIZE);
 265         addr = round_down(addr, EFI_PAGE_SIZE);
 266 
 267         mr.range.start = addr;
 268         mr.range.end = addr + size - 1;
 269         mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
 270 
 271         num_entries = efi_memmap_split_count(&md, &mr.range);
 272         num_entries += efi.memmap.nr_map;
 273 
 274         new_size = efi.memmap.desc_size * num_entries;
 275 
 276         new_phys = efi_memmap_alloc(num_entries);
 277         if (!new_phys) {
 278                 pr_err("Could not allocate boot services memmap\n");
 279                 return;
 280         }
 281 
 282         new = early_memremap(new_phys, new_size);
 283         if (!new) {
 284                 pr_err("Failed to map new boot services memmap\n");
 285                 return;
 286         }
 287 
 288         efi_memmap_insert(&efi.memmap, new, &mr);
 289         early_memunmap(new, new_size);
 290 
 291         efi_memmap_install(new_phys, num_entries);
 292         e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
 293         e820__update_table(e820_table);
 294 }
 295 
 296 /*
 297  * Helper function for efi_reserve_boot_services() to figure out if we
 298  * can free regions in efi_free_boot_services().
 299  *
 300  * Use this function to ensure we do not free regions owned by somebody
 301  * else. We must only reserve (and then free) regions:
 302  *
 303  * - Not within any part of the kernel
 304  * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
 305  */
 306 static __init bool can_free_region(u64 start, u64 size)
 307 {
 308         if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
 309                 return false;
 310 
 311         if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
 312                 return false;
 313 
 314         return true;
 315 }
 316 
 317 void __init efi_reserve_boot_services(void)
 318 {
 319         efi_memory_desc_t *md;
 320 
 321         for_each_efi_memory_desc(md) {
 322                 u64 start = md->phys_addr;
 323                 u64 size = md->num_pages << EFI_PAGE_SHIFT;
 324                 bool already_reserved;
 325 
 326                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 327                     md->type != EFI_BOOT_SERVICES_DATA)
 328                         continue;
 329 
 330                 already_reserved = memblock_is_region_reserved(start, size);
 331 
 332                 /*
 333                  * Because the following memblock_reserve() is paired
 334                  * with memblock_free_late() for this region in
 335                  * efi_free_boot_services(), we must be extremely
 336                  * careful not to reserve, and subsequently free,
 337                  * critical regions of memory (like the kernel image) or
 338                  * those regions that somebody else has already
 339                  * reserved.
 340                  *
 341                  * A good example of a critical region that must not be
 342                  * freed is page zero (first 4Kb of memory), which may
 343                  * contain boot services code/data but is marked
 344                  * E820_TYPE_RESERVED by trim_bios_range().
 345                  */
 346                 if (!already_reserved) {
 347                         memblock_reserve(start, size);
 348 
 349                         /*
 350                          * If we are the first to reserve the region, no
 351                          * one else cares about it. We own it and can
 352                          * free it later.
 353                          */
 354                         if (can_free_region(start, size))
 355                                 continue;
 356                 }
 357 
 358                 /*
 359                  * We don't own the region. We must not free it.
 360                  *
 361                  * Setting this bit for a boot services region really
 362                  * doesn't make sense as far as the firmware is
 363                  * concerned, but it does provide us with a way to tag
 364                  * those regions that must not be paired with
 365                  * memblock_free_late().
 366                  */
 367                 md->attribute |= EFI_MEMORY_RUNTIME;
 368         }
 369 }
 370 
 371 /*
 372  * Apart from having VA mappings for EFI boot services code/data regions,
 373  * (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So,
 374  * unmap both 1:1 and VA mappings.
 375  */
 376 static void __init efi_unmap_pages(efi_memory_desc_t *md)
 377 {
 378         pgd_t *pgd = efi_mm.pgd;
 379         u64 pa = md->phys_addr;
 380         u64 va = md->virt_addr;
 381 
 382         /*
 383          * To Do: Remove this check after adding functionality to unmap EFI boot
 384          * services code/data regions from direct mapping area because
 385          * "efi=old_map" maps EFI regions in swapper_pg_dir.
 386          */
 387         if (efi_enabled(EFI_OLD_MEMMAP))
 388                 return;
 389 
 390         /*
 391          * EFI mixed mode has all RAM mapped to access arguments while making
 392          * EFI runtime calls, hence don't unmap EFI boot services code/data
 393          * regions.
 394          */
 395         if (!efi_is_native())
 396                 return;
 397 
 398         if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
 399                 pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
 400 
 401         if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages))
 402                 pr_err("Failed to unmap VA mapping for 0x%llx\n", va);
 403 }
 404 
 405 void __init efi_free_boot_services(void)
 406 {
 407         phys_addr_t new_phys, new_size;
 408         efi_memory_desc_t *md;
 409         int num_entries = 0;
 410         void *new, *new_md;
 411 
 412         for_each_efi_memory_desc(md) {
 413                 unsigned long long start = md->phys_addr;
 414                 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
 415                 size_t rm_size;
 416 
 417                 if (md->type != EFI_BOOT_SERVICES_CODE &&
 418                     md->type != EFI_BOOT_SERVICES_DATA) {
 419                         num_entries++;
 420                         continue;
 421                 }
 422 
 423                 /* Do not free, someone else owns it: */
 424                 if (md->attribute & EFI_MEMORY_RUNTIME) {
 425                         num_entries++;
 426                         continue;
 427                 }
 428 
 429                 /*
 430                  * Before calling set_virtual_address_map(), EFI boot services
 431                  * code/data regions were mapped as a quirk for buggy firmware.
 432                  * Unmap them from efi_pgd before freeing them up.
 433                  */
 434                 efi_unmap_pages(md);
 435 
 436                 /*
 437                  * Nasty quirk: if all sub-1MB memory is used for boot
 438                  * services, we can get here without having allocated the
 439                  * real mode trampoline.  It's too late to hand boot services
 440                  * memory back to the memblock allocator, so instead
 441                  * try to manually allocate the trampoline if needed.
 442                  *
 443                  * I've seen this on a Dell XPS 13 9350 with firmware
 444                  * 1.4.4 with SGX enabled booting Linux via Fedora 24's
 445                  * grub2-efi on a hard disk.  (And no, I don't know why
 446                  * this happened, but Linux should still try to boot rather
 447                  * panicing early.)
 448                  */
 449                 rm_size = real_mode_size_needed();
 450                 if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
 451                         set_real_mode_mem(start);
 452                         start += rm_size;
 453                         size -= rm_size;
 454                 }
 455 
 456                 memblock_free_late(start, size);
 457         }
 458 
 459         if (!num_entries)
 460                 return;
 461 
 462         new_size = efi.memmap.desc_size * num_entries;
 463         new_phys = efi_memmap_alloc(num_entries);
 464         if (!new_phys) {
 465                 pr_err("Failed to allocate new EFI memmap\n");
 466                 return;
 467         }
 468 
 469         new = memremap(new_phys, new_size, MEMREMAP_WB);
 470         if (!new) {
 471                 pr_err("Failed to map new EFI memmap\n");
 472                 return;
 473         }
 474 
 475         /*
 476          * Build a new EFI memmap that excludes any boot services
 477          * regions that are not tagged EFI_MEMORY_RUNTIME, since those
 478          * regions have now been freed.
 479          */
 480         new_md = new;
 481         for_each_efi_memory_desc(md) {
 482                 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
 483                     (md->type == EFI_BOOT_SERVICES_CODE ||
 484                      md->type == EFI_BOOT_SERVICES_DATA))
 485                         continue;
 486 
 487                 memcpy(new_md, md, efi.memmap.desc_size);
 488                 new_md += efi.memmap.desc_size;
 489         }
 490 
 491         memunmap(new);
 492 
 493         if (efi_memmap_install(new_phys, num_entries)) {
 494                 pr_err("Could not install new EFI memmap\n");
 495                 return;
 496         }
 497 }
 498 
 499 /*
 500  * A number of config table entries get remapped to virtual addresses
 501  * after entering EFI virtual mode. However, the kexec kernel requires
 502  * their physical addresses therefore we pass them via setup_data and
 503  * correct those entries to their respective physical addresses here.
 504  *
 505  * Currently only handles smbios which is necessary for some firmware
 506  * implementation.
 507  */
 508 int __init efi_reuse_config(u64 tables, int nr_tables)
 509 {
 510         int i, sz, ret = 0;
 511         void *p, *tablep;
 512         struct efi_setup_data *data;
 513 
 514         if (nr_tables == 0)
 515                 return 0;
 516 
 517         if (!efi_setup)
 518                 return 0;
 519 
 520         if (!efi_enabled(EFI_64BIT))
 521                 return 0;
 522 
 523         data = early_memremap(efi_setup, sizeof(*data));
 524         if (!data) {
 525                 ret = -ENOMEM;
 526                 goto out;
 527         }
 528 
 529         if (!data->smbios)
 530                 goto out_memremap;
 531 
 532         sz = sizeof(efi_config_table_64_t);
 533 
 534         p = tablep = early_memremap(tables, nr_tables * sz);
 535         if (!p) {
 536                 pr_err("Could not map Configuration table!\n");
 537                 ret = -ENOMEM;
 538                 goto out_memremap;
 539         }
 540 
 541         for (i = 0; i < efi.systab->nr_tables; i++) {
 542                 efi_guid_t guid;
 543 
 544                 guid = ((efi_config_table_64_t *)p)->guid;
 545 
 546                 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
 547                         ((efi_config_table_64_t *)p)->table = data->smbios;
 548                 p += sz;
 549         }
 550         early_memunmap(tablep, nr_tables * sz);
 551 
 552 out_memremap:
 553         early_memunmap(data, sizeof(*data));
 554 out:
 555         return ret;
 556 }
 557 
 558 static const struct dmi_system_id sgi_uv1_dmi[] = {
 559         { NULL, "SGI UV1",
 560                 {       DMI_MATCH(DMI_PRODUCT_NAME,     "Stoutland Platform"),
 561                         DMI_MATCH(DMI_PRODUCT_VERSION,  "1.0"),
 562                         DMI_MATCH(DMI_BIOS_VENDOR,      "SGI.COM"),
 563                 }
 564         },
 565         { } /* NULL entry stops DMI scanning */
 566 };
 567 
 568 void __init efi_apply_memmap_quirks(void)
 569 {
 570         /*
 571          * Once setup is done earlier, unmap the EFI memory map on mismatched
 572          * firmware/kernel architectures since there is no support for runtime
 573          * services.
 574          */
 575         if (!efi_runtime_supported()) {
 576                 pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
 577                 efi_memmap_unmap();
 578         }
 579 
 580         /* UV2+ BIOS has a fix for this issue.  UV1 still needs the quirk. */
 581         if (dmi_check_system(sgi_uv1_dmi))
 582                 set_bit(EFI_OLD_MEMMAP, &efi.flags);
 583 }
 584 
 585 /*
 586  * For most modern platforms the preferred method of powering off is via
 587  * ACPI. However, there are some that are known to require the use of
 588  * EFI runtime services and for which ACPI does not work at all.
 589  *
 590  * Using EFI is a last resort, to be used only if no other option
 591  * exists.
 592  */
 593 bool efi_reboot_required(void)
 594 {
 595         if (!acpi_gbl_reduced_hardware)
 596                 return false;
 597 
 598         efi_reboot_quirk_mode = EFI_RESET_WARM;
 599         return true;
 600 }
 601 
 602 bool efi_poweroff_required(void)
 603 {
 604         return acpi_gbl_reduced_hardware || acpi_no_s5;
 605 }
 606 
 607 #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
 608 
 609 static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
 610                                   size_t hdr_bytes)
 611 {
 612         struct quark_security_header *csh = *pkbuff;
 613 
 614         /* Only process data block that is larger than the security header */
 615         if (hdr_bytes < sizeof(struct quark_security_header))
 616                 return 0;
 617 
 618         if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
 619             csh->headersize != QUARK_SECURITY_HEADER_SIZE)
 620                 return 1;
 621 
 622         /* Only process data block if EFI header is included */
 623         if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
 624                         sizeof(efi_capsule_header_t))
 625                 return 0;
 626 
 627         pr_debug("Quark security header detected\n");
 628 
 629         if (csh->rsvd_next_header != 0) {
 630                 pr_err("multiple Quark security headers not supported\n");
 631                 return -EINVAL;
 632         }
 633 
 634         *pkbuff += csh->headersize;
 635         cap_info->total_size = csh->headersize;
 636 
 637         /*
 638          * Update the first page pointer to skip over the CSH header.
 639          */
 640         cap_info->phys[0] += csh->headersize;
 641 
 642         /*
 643          * cap_info->capsule should point at a virtual mapping of the entire
 644          * capsule, starting at the capsule header. Our image has the Quark
 645          * security header prepended, so we cannot rely on the default vmap()
 646          * mapping created by the generic capsule code.
 647          * Given that the Quark firmware does not appear to care about the
 648          * virtual mapping, let's just point cap_info->capsule at our copy
 649          * of the capsule header.
 650          */
 651         cap_info->capsule = &cap_info->header;
 652 
 653         return 1;
 654 }
 655 
 656 #define ICPU(family, model, quirk_handler) \
 657         { X86_VENDOR_INTEL, family, model, X86_FEATURE_ANY, \
 658           (unsigned long)&quirk_handler }
 659 
 660 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
 661         ICPU(5, 9, qrk_capsule_setup_info),     /* Intel Quark X1000 */
 662         { }
 663 };
 664 
 665 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
 666                            size_t hdr_bytes)
 667 {
 668         int (*quirk_handler)(struct capsule_info *, void **, size_t);
 669         const struct x86_cpu_id *id;
 670         int ret;
 671 
 672         if (hdr_bytes < sizeof(efi_capsule_header_t))
 673                 return 0;
 674 
 675         cap_info->total_size = 0;
 676 
 677         id = x86_match_cpu(efi_capsule_quirk_ids);
 678         if (id) {
 679                 /*
 680                  * The quirk handler is supposed to return
 681                  *  - a value > 0 if the setup should continue, after advancing
 682                  *    kbuff as needed
 683                  *  - 0 if not enough hdr_bytes are available yet
 684                  *  - a negative error code otherwise
 685                  */
 686                 quirk_handler = (typeof(quirk_handler))id->driver_data;
 687                 ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
 688                 if (ret <= 0)
 689                         return ret;
 690         }
 691 
 692         memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
 693 
 694         cap_info->total_size += cap_info->header.imagesize;
 695 
 696         return __efi_capsule_setup_info(cap_info);
 697 }
 698 
 699 #endif
 700 
 701 /*
 702  * If any access by any efi runtime service causes a page fault, then,
 703  * 1. If it's efi_reset_system(), reboot through BIOS.
 704  * 2. If any other efi runtime service, then
 705  *    a. Return error status to the efi caller process.
 706  *    b. Disable EFI Runtime Services forever and
 707  *    c. Freeze efi_rts_wq and schedule new process.
 708  *
 709  * @return: Returns, if the page fault is not handled. This function
 710  * will never return if the page fault is handled successfully.
 711  */
 712 void efi_recover_from_page_fault(unsigned long phys_addr)
 713 {
 714         if (!IS_ENABLED(CONFIG_X86_64))
 715                 return;
 716 
 717         /*
 718          * Make sure that an efi runtime service caused the page fault.
 719          * "efi_mm" cannot be used to check if the page fault had occurred
 720          * in the firmware context because efi=old_map doesn't use efi_pgd.
 721          */
 722         if (efi_rts_work.efi_rts_id == EFI_NONE)
 723                 return;
 724 
 725         /*
 726          * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
 727          * page faulting on these addresses isn't expected.
 728          */
 729         if (phys_addr <= 0x0fff)
 730                 return;
 731 
 732         /*
 733          * Print stack trace as it might be useful to know which EFI Runtime
 734          * Service is buggy.
 735          */
 736         WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
 737              phys_addr);
 738 
 739         /*
 740          * Buggy efi_reset_system() is handled differently from other EFI
 741          * Runtime Services as it doesn't use efi_rts_wq. Although,
 742          * native_machine_emergency_restart() says that machine_real_restart()
 743          * could fail, it's better not to compilcate this fault handler
 744          * because this case occurs *very* rarely and hence could be improved
 745          * on a need by basis.
 746          */
 747         if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
 748                 pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
 749                 machine_real_restart(MRR_BIOS);
 750                 return;
 751         }
 752 
 753         /*
 754          * Before calling EFI Runtime Service, the kernel has switched the
 755          * calling process to efi_mm. Hence, switch back to task_mm.
 756          */
 757         arch_efi_call_virt_teardown();
 758 
 759         /* Signal error status to the efi caller process */
 760         efi_rts_work.status = EFI_ABORTED;
 761         complete(&efi_rts_work.efi_rts_comp);
 762 
 763         clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 764         pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
 765 
 766         /*
 767          * Call schedule() in an infinite loop, so that any spurious wake ups
 768          * will never run efi_rts_wq again.
 769          */
 770         for (;;) {
 771                 set_current_state(TASK_IDLE);
 772                 schedule();
 773         }
 774 
 775         return;
 776 }

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