drivers/firmware/efi/libstub/x86-stub.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 /* -----------------------------------------------------------------------
   4  *
   5  *   Copyright 2011 Intel Corporation; author Matt Fleming
   6  *
   7  * ----------------------------------------------------------------------- */
   8
   9 #include <linux/efi.h>
  10 #include <linux/pci.h>
  11 #include <linux/stddef.h>
  12
  13 #include <asm/efi.h>
  14 #include <asm/e820/types.h>
  15 #include <asm/setup.h>
  16 #include <asm/desc.h>
  17 #include <asm/boot.h>
  18
  19 #include "efistub.h"
  20
  21 /* Maximum physical address for 64-bit kernel with 4-level paging */
  22 #define MAXMEM_X86_64_4LEVEL (1ull << 46)
  23
  24 const efi_system_table_t *efi_system_table;
  25 extern u32 image_offset;
  26 static efi_loaded_image_t *image = NULL;
  27
  28 static efi_status_t
  29 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
  30 {
  31         struct pci_setup_rom *rom = NULL;
  32         efi_status_t status;
  33         unsigned long size;
  34         uint64_t romsize;
  35         void *romimage;
  36
  37         /*
  38          * Some firmware images contain EFI function pointers at the place where
  39          * the romimage and romsize fields are supposed to be. Typically the EFI
  40          * code is mapped at high addresses, translating to an unrealistically
  41          * large romsize. The UEFI spec limits the size of option ROMs to 16
  42          * MiB so we reject any ROMs over 16 MiB in size to catch this.
  43          */
  44         romimage = efi_table_attr(pci, romimage);
  45         romsize = efi_table_attr(pci, romsize);
  46         if (!romimage || !romsize || romsize > SZ_16M)
  47                 return EFI_INVALID_PARAMETER;
  48
  49         size = romsize + sizeof(*rom);
  50
  51         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
  52                              (void **)&rom);
  53         if (status != EFI_SUCCESS) {
  54                 efi_err("Failed to allocate memory for 'rom'\n");
  55                 return status;
  56         }
  57
  58         memset(rom, 0, sizeof(*rom));
  59
  60         rom->data.type  = SETUP_PCI;
  61         rom->data.len   = size - sizeof(struct setup_data);
  62         rom->data.next  = 0;
  63         rom->pcilen     = pci->romsize;
  64         *__rom = rom;
  65
  66         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  67                                 PCI_VENDOR_ID, 1, &rom->vendor);
  68
  69         if (status != EFI_SUCCESS) {
  70                 efi_err("Failed to read rom->vendor\n");
  71                 goto free_struct;
  72         }
  73
  74         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  75                                 PCI_DEVICE_ID, 1, &rom->devid);
  76
  77         if (status != EFI_SUCCESS) {
  78                 efi_err("Failed to read rom->devid\n");
  79                 goto free_struct;
  80         }
  81
  82         status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
  83                                 &rom->device, &rom->function);
  84
  85         if (status != EFI_SUCCESS)
  86                 goto free_struct;
  87
  88         memcpy(rom->romdata, romimage, romsize);
  89         return status;
  90
  91 free_struct:
  92         efi_bs_call(free_pool, rom);
  93         return status;
  94 }
  95
  96 /*
  97  * There's no way to return an informative status from this function,
  98  * because any analysis (and printing of error messages) needs to be
  99  * done directly at the EFI function call-site.
 100  *
 101  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 102  * just didn't find any PCI devices, but there's no way to tell outside
 103  * the context of the call.
 104  */
 105 static void setup_efi_pci(struct boot_params *params)
 106 {
 107         efi_status_t status;
 108         void **pci_handle = NULL;
 109         efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 110         unsigned long size = 0;
 111         struct setup_data *data;
 112         efi_handle_t h;
 113         int i;
 114
 115         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 116                              &pci_proto, NULL, &size, pci_handle);
 117
 118         if (status == EFI_BUFFER_TOO_SMALL) {
 119                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 120                                      (void **)&pci_handle);
 121
 122                 if (status != EFI_SUCCESS) {
 123                         efi_err("Failed to allocate memory for 'pci_handle'\n");
 124                         return;
 125                 }
 126
 127                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 128                                      &pci_proto, NULL, &size, pci_handle);
 129         }
 130
 131         if (status != EFI_SUCCESS)
 132                 goto free_handle;
 133
 134         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 135
 136         while (data && data->next)
 137                 data = (struct setup_data *)(unsigned long)data->next;
 138
 139         for_each_efi_handle(h, pci_handle, size, i) {
 140                 efi_pci_io_protocol_t *pci = NULL;
 141                 struct pci_setup_rom *rom;
 142
 143                 status = efi_bs_call(handle_protocol, h, &pci_proto,
 144                                      (void **)&pci);
 145                 if (status != EFI_SUCCESS || !pci)
 146                         continue;
 147
 148                 status = preserve_pci_rom_image(pci, &rom);
 149                 if (status != EFI_SUCCESS)
 150                         continue;
 151
 152                 if (data)
 153                         data->next = (unsigned long)rom;
 154                 else
 155                         params->hdr.setup_data = (unsigned long)rom;
 156
 157                 data = (struct setup_data *)rom;
 158         }
 159
 160 free_handle:
 161         efi_bs_call(free_pool, pci_handle);
 162 }
 163
 164 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 165 {
 166         efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 167         struct setup_data *data, *new;
 168         efi_status_t status;
 169         u32 size = 0;
 170         apple_properties_protocol_t *p;
 171
 172         status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 173         if (status != EFI_SUCCESS)
 174                 return;
 175
 176         if (efi_table_attr(p, version) != 0x10000) {
 177                 efi_err("Unsupported properties proto version\n");
 178                 return;
 179         }
 180
 181         efi_call_proto(p, get_all, NULL, &size);
 182         if (!size)
 183                 return;
 184
 185         do {
 186                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 187                                      size + sizeof(struct setup_data),
 188                                      (void **)&new);
 189                 if (status != EFI_SUCCESS) {
 190                         efi_err("Failed to allocate memory for 'properties'\n");
 191                         return;
 192                 }
 193
 194                 status = efi_call_proto(p, get_all, new->data, &size);
 195
 196                 if (status == EFI_BUFFER_TOO_SMALL)
 197                         efi_bs_call(free_pool, new);
 198         } while (status == EFI_BUFFER_TOO_SMALL);
 199
 200         new->type = SETUP_APPLE_PROPERTIES;
 201         new->len  = size;
 202         new->next = 0;
 203
 204         data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 205         if (!data) {
 206                 boot_params->hdr.setup_data = (unsigned long)new;
 207         } else {
 208                 while (data->next)
 209                         data = (struct setup_data *)(unsigned long)data->next;
 210                 data->next = (unsigned long)new;
 211         }
 212 }
 213
 214 static const efi_char16_t apple[] = L"Apple";
 215
 216 static void setup_quirks(struct boot_params *boot_params)
 217 {
 218         efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 219                 efi_table_attr(efi_system_table, fw_vendor);
 220
 221         if (!memcmp(fw_vendor, apple, sizeof(apple))) {
 222                 if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
 223                         retrieve_apple_device_properties(boot_params);
 224         }
 225 }
 226
 227 /*
 228  * See if we have Universal Graphics Adapter (UGA) protocol
 229  */
 230 static efi_status_t
 231 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 232 {
 233         efi_status_t status;
 234         u32 width, height;
 235         void **uga_handle = NULL;
 236         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 237         efi_handle_t handle;
 238         int i;
 239
 240         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 241                              (void **)&uga_handle);
 242         if (status != EFI_SUCCESS)
 243                 return status;
 244
 245         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 246                              uga_proto, NULL, &size, uga_handle);
 247         if (status != EFI_SUCCESS)
 248                 goto free_handle;
 249
 250         height = 0;
 251         width = 0;
 252
 253         first_uga = NULL;
 254         for_each_efi_handle(handle, uga_handle, size, i) {
 255                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 256                 u32 w, h, depth, refresh;
 257                 void *pciio;
 258
 259                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 260                                      (void **)&uga);
 261                 if (status != EFI_SUCCESS)
 262                         continue;
 263
 264                 pciio = NULL;
 265                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 266
 267                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 268                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 269                         width = w;
 270                         height = h;
 271
 272                         /*
 273                          * Once we've found a UGA supporting PCIIO,
 274                          * don't bother looking any further.
 275                          */
 276                         if (pciio)
 277                                 break;
 278
 279                         first_uga = uga;
 280                 }
 281         }
 282
 283         if (!width && !height)
 284                 goto free_handle;
 285
 286         /* EFI framebuffer */
 287         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 288
 289         si->lfb_depth           = 32;
 290         si->lfb_width           = width;
 291         si->lfb_height          = height;
 292
 293         si->red_size            = 8;
 294         si->red_pos             = 16;
 295         si->green_size          = 8;
 296         si->green_pos           = 8;
 297         si->blue_size           = 8;
 298         si->blue_pos            = 0;
 299         si->rsvd_size           = 8;
 300         si->rsvd_pos            = 24;
 301
 302 free_handle:
 303         efi_bs_call(free_pool, uga_handle);
 304
 305         return status;
 306 }
 307
 308 static void setup_graphics(struct boot_params *boot_params)
 309 {
 310         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 311         struct screen_info *si;
 312         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 313         efi_status_t status;
 314         unsigned long size;
 315         void **gop_handle = NULL;
 316         void **uga_handle = NULL;
 317
 318         si = &boot_params->screen_info;
 319         memset(si, 0, sizeof(*si));
 320
 321         size = 0;
 322         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 323                              &graphics_proto, NULL, &size, gop_handle);
 324         if (status == EFI_BUFFER_TOO_SMALL)
 325                 status = efi_setup_gop(si, &graphics_proto, size);
 326
 327         if (status != EFI_SUCCESS) {
 328                 size = 0;
 329                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 330                                      &uga_proto, NULL, &size, uga_handle);
 331                 if (status == EFI_BUFFER_TOO_SMALL)
 332                         setup_uga(si, &uga_proto, size);
 333         }
 334 }
 335
 336
 337 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 338 {
 339         efi_bs_call(exit, handle, status, 0, NULL);
 340         for(;;)
 341                 asm("hlt");
 342 }
 343
 344 void startup_32(struct boot_params *boot_params);
 345
 346 void __noreturn efi_stub_entry(efi_handle_t handle,
 347                                efi_system_table_t *sys_table_arg,
 348                                struct boot_params *boot_params);
 349
 350 /*
 351  * Because the x86 boot code expects to be passed a boot_params we
 352  * need to create one ourselves (usually the bootloader would create
 353  * one for us).
 354  */
 355 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 356                                    efi_system_table_t *sys_table_arg)
 357 {
 358         struct boot_params *boot_params;
 359         struct setup_header *hdr;
 360         void *image_base;
 361         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 362         int options_size = 0;
 363         efi_status_t status;
 364         char *cmdline_ptr;
 365
 366         efi_system_table = sys_table_arg;
 367
 368         /* Check if we were booted by the EFI firmware */
 369         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 370                 efi_exit(handle, EFI_INVALID_PARAMETER);
 371
 372         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 373         if (status != EFI_SUCCESS) {
 374                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 375                 efi_exit(handle, status);
 376         }
 377
 378         image_base = efi_table_attr(image, image_base);
 379         image_offset = (void *)startup_32 - image_base;
 380
 381         status = efi_allocate_pages(sizeof(struct boot_params),
 382                                     (unsigned long *)&boot_params, ULONG_MAX);
 383         if (status != EFI_SUCCESS) {
 384                 efi_err("Failed to allocate lowmem for boot params\n");
 385                 efi_exit(handle, status);
 386         }
 387
 388         memset(boot_params, 0x0, sizeof(struct boot_params));
 389
 390         hdr = &boot_params->hdr;
 391
 392         /* Copy the setup header from the second sector to boot_params */
 393         memcpy(&hdr->jump, image_base + 512,
 394                sizeof(struct setup_header) - offsetof(struct setup_header, jump));
 395
 396         /*
 397          * Fill out some of the header fields ourselves because the
 398          * EFI firmware loader doesn't load the first sector.
 399          */
 400         hdr->root_flags = 1;
 401         hdr->vid_mode   = 0xffff;
 402         hdr->boot_flag  = 0xAA55;
 403
 404         hdr->type_of_loader = 0x21;
 405
 406         /* Convert unicode cmdline to ascii */
 407         cmdline_ptr = efi_convert_cmdline(image, &options_size);
 408         if (!cmdline_ptr)
 409                 goto fail;
 410
 411         efi_set_u64_split((unsigned long)cmdline_ptr,
 412                           &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);
 413
 414         hdr->ramdisk_image = 0;
 415         hdr->ramdisk_size = 0;
 416
 417         efi_stub_entry(handle, sys_table_arg, boot_params);
 418         /* not reached */
 419
 420 fail:
 421         efi_free(sizeof(struct boot_params), (unsigned long)boot_params);
 422
 423         efi_exit(handle, status);
 424 }
 425
 426 static void add_e820ext(struct boot_params *params,
 427                         struct setup_data *e820ext, u32 nr_entries)
 428 {
 429         struct setup_data *data;
 430
 431         e820ext->type = SETUP_E820_EXT;
 432         e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 433         e820ext->next = 0;
 434
 435         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 436
 437         while (data && data->next)
 438                 data = (struct setup_data *)(unsigned long)data->next;
 439
 440         if (data)
 441                 data->next = (unsigned long)e820ext;
 442         else
 443                 params->hdr.setup_data = (unsigned long)e820ext;
 444 }
 445
 446 static efi_status_t
 447 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 448 {
 449         struct boot_e820_entry *entry = params->e820_table;
 450         struct efi_info *efi = &params->efi_info;
 451         struct boot_e820_entry *prev = NULL;
 452         u32 nr_entries;
 453         u32 nr_desc;
 454         int i;
 455
 456         nr_entries = 0;
 457         nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
 458
 459         for (i = 0; i < nr_desc; i++) {
 460                 efi_memory_desc_t *d;
 461                 unsigned int e820_type = 0;
 462                 unsigned long m = efi->efi_memmap;
 463
 464 #ifdef CONFIG_X86_64
 465                 m |= (u64)efi->efi_memmap_hi << 32;
 466 #endif
 467
 468                 d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 469                 switch (d->type) {
 470                 case EFI_RESERVED_TYPE:
 471                 case EFI_RUNTIME_SERVICES_CODE:
 472                 case EFI_RUNTIME_SERVICES_DATA:
 473                 case EFI_MEMORY_MAPPED_IO:
 474                 case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 475                 case EFI_PAL_CODE:
 476                         e820_type = E820_TYPE_RESERVED;
 477                         break;
 478
 479                 case EFI_UNUSABLE_MEMORY:
 480                         e820_type = E820_TYPE_UNUSABLE;
 481                         break;
 482
 483                 case EFI_ACPI_RECLAIM_MEMORY:
 484                         e820_type = E820_TYPE_ACPI;
 485                         break;
 486
 487                 case EFI_LOADER_CODE:
 488                 case EFI_LOADER_DATA:
 489                 case EFI_BOOT_SERVICES_CODE:
 490                 case EFI_BOOT_SERVICES_DATA:
 491                 case EFI_CONVENTIONAL_MEMORY:
 492                         if (efi_soft_reserve_enabled() &&
 493                             (d->attribute & EFI_MEMORY_SP))
 494                                 e820_type = E820_TYPE_SOFT_RESERVED;
 495                         else
 496                                 e820_type = E820_TYPE_RAM;
 497                         break;
 498
 499                 case EFI_ACPI_MEMORY_NVS:
 500                         e820_type = E820_TYPE_NVS;
 501                         break;
 502
 503                 case EFI_PERSISTENT_MEMORY:
 504                         e820_type = E820_TYPE_PMEM;
 505                         break;
 506
 507                 default:
 508                         continue;
 509                 }
 510
 511                 /* Merge adjacent mappings */
 512                 if (prev && prev->type == e820_type &&
 513                     (prev->addr + prev->size) == d->phys_addr) {
 514                         prev->size += d->num_pages << 12;
 515                         continue;
 516                 }
 517
 518                 if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 519                         u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 520                                    sizeof(struct setup_data);
 521
 522                         if (!e820ext || e820ext_size < need)
 523                                 return EFI_BUFFER_TOO_SMALL;
 524
 525                         /* boot_params map full, switch to e820 extended */
 526                         entry = (struct boot_e820_entry *)e820ext->data;
 527                 }
 528
 529                 entry->addr = d->phys_addr;
 530                 entry->size = d->num_pages << PAGE_SHIFT;
 531                 entry->type = e820_type;
 532                 prev = entry++;
 533                 nr_entries++;
 534         }
 535
 536         if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 537                 u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
 538
 539                 add_e820ext(params, e820ext, nr_e820ext);
 540                 nr_entries -= nr_e820ext;
 541         }
 542
 543         params->e820_entries = (u8)nr_entries;
 544
 545         return EFI_SUCCESS;
 546 }
 547
 548 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 549                                   u32 *e820ext_size)
 550 {
 551         efi_status_t status;
 552         unsigned long size;
 553
 554         size = sizeof(struct setup_data) +
 555                 sizeof(struct e820_entry) * nr_desc;
 556
 557         if (*e820ext) {
 558                 efi_bs_call(free_pool, *e820ext);
 559                 *e820ext = NULL;
 560                 *e820ext_size = 0;
 561         }
 562
 563         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 564                              (void **)e820ext);
 565         if (status == EFI_SUCCESS)
 566                 *e820ext_size = size;
 567
 568         return status;
 569 }
 570
 571 static efi_status_t allocate_e820(struct boot_params *params,
 572                                   struct setup_data **e820ext,
 573                                   u32 *e820ext_size)
 574 {
 575         unsigned long map_size, desc_size, map_key;
 576         efi_status_t status;
 577         __u32 nr_desc, desc_version;
 578
 579         /* Only need the size of the mem map and size of each mem descriptor */
 580         map_size = 0;
 581         status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
 582                              &desc_size, &desc_version);
 583         if (status != EFI_BUFFER_TOO_SMALL)
 584                 return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
 585
 586         nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
 587
 588         if (nr_desc > ARRAY_SIZE(params->e820_table)) {
 589                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
 590
 591                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 592                 if (status != EFI_SUCCESS)
 593                         return status;
 594         }
 595
 596         return EFI_SUCCESS;
 597 }
 598
 599 struct exit_boot_struct {
 600         struct boot_params      *boot_params;
 601         struct efi_info         *efi;
 602 };
 603
 604 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 605                                    void *priv)
 606 {
 607         const char *signature;
 608         struct exit_boot_struct *p = priv;
 609
 610         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 611                                    : EFI32_LOADER_SIGNATURE;
 612         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 613
 614         efi_set_u64_split((unsigned long)efi_system_table,
 615                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 616         p->efi->efi_memdesc_size        = *map->desc_size;
 617         p->efi->efi_memdesc_version     = *map->desc_ver;
 618         efi_set_u64_split((unsigned long)*map->map,
 619                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 620         p->efi->efi_memmap_size         = *map->map_size;
 621
 622         return EFI_SUCCESS;
 623 }
 624
 625 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 626 {
 627         unsigned long map_sz, key, desc_size, buff_size;
 628         efi_memory_desc_t *mem_map;
 629         struct setup_data *e820ext = NULL;
 630         __u32 e820ext_size = 0;
 631         efi_status_t status;
 632         __u32 desc_version;
 633         struct efi_boot_memmap map;
 634         struct exit_boot_struct priv;
 635
 636         map.map                 = &mem_map;
 637         map.map_size            = &map_sz;
 638         map.desc_size           = &desc_size;
 639         map.desc_ver            = &desc_version;
 640         map.key_ptr             = &key;
 641         map.buff_size           = &buff_size;
 642         priv.boot_params        = boot_params;
 643         priv.efi                = &boot_params->efi_info;
 644
 645         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 646         if (status != EFI_SUCCESS)
 647                 return status;
 648
 649         /* Might as well exit boot services now */
 650         status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
 651         if (status != EFI_SUCCESS)
 652                 return status;
 653
 654         /* Historic? */
 655         boot_params->alt_mem_k  = 32 * 1024;
 656
 657         status = setup_e820(boot_params, e820ext, e820ext_size);
 658         if (status != EFI_SUCCESS)
 659                 return status;
 660
 661         return EFI_SUCCESS;
 662 }
 663
 664 /*
 665  * On success, we return the address of startup_32, which has potentially been
 666  * relocated by efi_relocate_kernel.
 667  * On failure, we exit to the firmware via efi_exit instead of returning.
 668  */
 669 unsigned long efi_main(efi_handle_t handle,
 670                              efi_system_table_t *sys_table_arg,
 671                              struct boot_params *boot_params)
 672 {
 673         unsigned long bzimage_addr = (unsigned long)startup_32;
 674         unsigned long buffer_start, buffer_end;
 675         struct setup_header *hdr = &boot_params->hdr;
 676         efi_status_t status;
 677
 678         efi_system_table = sys_table_arg;
 679
 680         /* Check if we were booted by the EFI firmware */
 681         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 682                 efi_exit(handle, EFI_INVALID_PARAMETER);
 683
 684         /*
 685          * If the kernel isn't already loaded at a suitable address,
 686          * relocate it.
 687          *
 688          * It must be loaded above LOAD_PHYSICAL_ADDR.
 689          *
 690          * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
 691          * is defined as the macro MAXMEM, but unfortunately that is not a
 692          * compile-time constant if 5-level paging is configured, so we instead
 693          * define our own macro for use here.
 694          *
 695          * For 32-bit, the maximum address is complicated to figure out, for
 696          * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
 697          * KASLR uses.
 698          *
 699          * Also relocate it if image_offset is zero, i.e. the kernel wasn't
 700          * loaded by LoadImage, but rather by a bootloader that called the
 701          * handover entry. The reason we must always relocate in this case is
 702          * to handle the case of systemd-boot booting a unified kernel image,
 703          * which is a PE executable that contains the bzImage and an initrd as
 704          * COFF sections. The initrd section is placed after the bzImage
 705          * without ensuring that there are at least init_size bytes available
 706          * for the bzImage, and thus the compressed kernel's startup code may
 707          * overwrite the initrd unless it is moved out of the way.
 708          */
 709
 710         buffer_start = ALIGN(bzimage_addr - image_offset,
 711                              hdr->kernel_alignment);
 712         buffer_end = buffer_start + hdr->init_size;
 713
 714         if ((buffer_start < LOAD_PHYSICAL_ADDR)                              ||
 715             (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE)    ||
 716             (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
 717             (image_offset == 0)) {
 718                 extern char _bss[];
 719
 720                 status = efi_relocate_kernel(&bzimage_addr,
 721                                              (unsigned long)_bss - bzimage_addr,
 722                                              hdr->init_size,
 723                                              hdr->pref_address,
 724                                              hdr->kernel_alignment,
 725                                              LOAD_PHYSICAL_ADDR);
 726                 if (status != EFI_SUCCESS) {
 727                         efi_err("efi_relocate_kernel() failed!\n");
 728                         goto fail;
 729                 }
 730                 /*
 731                  * Now that we've copied the kernel elsewhere, we no longer
 732                  * have a set up block before startup_32(), so reset image_offset
 733                  * to zero in case it was set earlier.
 734                  */
 735                 image_offset = 0;
 736         }
 737
 738 #ifdef CONFIG_CMDLINE_BOOL
 739         status = efi_parse_options(CONFIG_CMDLINE);
 740         if (status != EFI_SUCCESS) {
 741                 efi_err("Failed to parse options\n");
 742                 goto fail;
 743         }
 744 #endif
 745         if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 746                 unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 747                                                ((u64)boot_params->ext_cmd_line_ptr << 32));
 748                 status = efi_parse_options((char *)cmdline_paddr);
 749                 if (status != EFI_SUCCESS) {
 750                         efi_err("Failed to parse options\n");
 751                         goto fail;
 752                 }
 753         }
 754
 755         /*
 756          * At this point, an initrd may already have been loaded by the
 757          * bootloader and passed via bootparams. We permit an initrd loaded
 758          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 759          *
 760          * If the device path is not present, any command-line initrd=
 761          * arguments will be processed only if image is not NULL, which will be
 762          * the case only if we were loaded via the PE entry point.
 763          */
 764         if (!efi_noinitrd) {
 765                 unsigned long addr, size;
 766
 767                 status = efi_load_initrd(image, &addr, &size,
 768                                          hdr->initrd_addr_max, ULONG_MAX);
 769
 770                 if (status != EFI_SUCCESS) {
 771                         efi_err("Failed to load initrd!\n");
 772                         goto fail;
 773                 }
 774                 if (size > 0) {
 775                         efi_set_u64_split(addr, &hdr->ramdisk_image,
 776                                           &boot_params->ext_ramdisk_image);
 777                         efi_set_u64_split(size, &hdr->ramdisk_size,
 778                                           &boot_params->ext_ramdisk_size);
 779                 }
 780         }
 781
 782         /*
 783          * If the boot loader gave us a value for secure_boot then we use that,
 784          * otherwise we ask the BIOS.
 785          */
 786         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 787                 boot_params->secure_boot = efi_get_secureboot();
 788
 789         /* Ask the firmware to clear memory on unclean shutdown */
 790         efi_enable_reset_attack_mitigation();
 791
 792         efi_random_get_seed();
 793
 794         efi_retrieve_tpm2_eventlog();
 795
 796         setup_graphics(boot_params);
 797
 798         setup_efi_pci(boot_params);
 799
 800         setup_quirks(boot_params);
 801
 802         status = exit_boot(boot_params, handle);
 803         if (status != EFI_SUCCESS) {
 804                 efi_err("exit_boot() failed!\n");
 805                 goto fail;
 806         }
 807
 808         return bzimage_addr;
 809 fail:
 810         efi_err("efi_main() failed!\n");
 811
 812         efi_exit(handle, status);
 813 }