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
  12 #include <asm/efi.h>
  13 #include <asm/e820/types.h>
  14 #include <asm/setup.h>
  15 #include <asm/desc.h>
  16 #include <asm/boot.h>
  17
  18 #include "efistub.h"
  19
  20 /* Maximum physical address for 64-bit kernel with 4-level paging */
  21 #define MAXMEM_X86_64_4LEVEL (1ull << 46)
  22
  23 const efi_system_table_t *efi_system_table;
  24 extern u32 image_offset;
  25 static efi_loaded_image_t *image = NULL;
  26
  27 static efi_status_t
  28 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
  29 {
  30         struct pci_setup_rom *rom = NULL;
  31         efi_status_t status;
  32         unsigned long size;
  33         uint64_t romsize;
  34         void *romimage;
  35
  36         /*
  37          * Some firmware images contain EFI function pointers at the place where
  38          * the romimage and romsize fields are supposed to be. Typically the EFI
  39          * code is mapped at high addresses, translating to an unrealistically
  40          * large romsize. The UEFI spec limits the size of option ROMs to 16
  41          * MiB so we reject any ROMs over 16 MiB in size to catch this.
  42          */
  43         romimage = efi_table_attr(pci, romimage);
  44         romsize = efi_table_attr(pci, romsize);
  45         if (!romimage || !romsize || romsize > SZ_16M)
  46                 return EFI_INVALID_PARAMETER;
  47
  48         size = romsize + sizeof(*rom);
  49
  50         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
  51                              (void **)&rom);
  52         if (status != EFI_SUCCESS) {
  53                 efi_err("Failed to allocate memory for 'rom'\n");
  54                 return status;
  55         }
  56
  57         memset(rom, 0, sizeof(*rom));
  58
  59         rom->data.type  = SETUP_PCI;
  60         rom->data.len   = size - sizeof(struct setup_data);
  61         rom->data.next  = 0;
  62         rom->pcilen     = pci->romsize;
  63         *__rom = rom;
  64
  65         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  66                                 PCI_VENDOR_ID, 1, &rom->vendor);
  67
  68         if (status != EFI_SUCCESS) {
  69                 efi_err("Failed to read rom->vendor\n");
  70                 goto free_struct;
  71         }
  72
  73         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  74                                 PCI_DEVICE_ID, 1, &rom->devid);
  75
  76         if (status != EFI_SUCCESS) {
  77                 efi_err("Failed to read rom->devid\n");
  78                 goto free_struct;
  79         }
  80
  81         status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
  82                                 &rom->device, &rom->function);
  83
  84         if (status != EFI_SUCCESS)
  85                 goto free_struct;
  86
  87         memcpy(rom->romdata, romimage, romsize);
  88         return status;
  89
  90 free_struct:
  91         efi_bs_call(free_pool, rom);
  92         return status;
  93 }
  94
  95 /*
  96  * There's no way to return an informative status from this function,
  97  * because any analysis (and printing of error messages) needs to be
  98  * done directly at the EFI function call-site.
  99  *
 100  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 101  * just didn't find any PCI devices, but there's no way to tell outside
 102  * the context of the call.
 103  */
 104 static void setup_efi_pci(struct boot_params *params)
 105 {
 106         efi_status_t status;
 107         void **pci_handle = NULL;
 108         efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 109         unsigned long size = 0;
 110         struct setup_data *data;
 111         efi_handle_t h;
 112         int i;
 113
 114         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 115                              &pci_proto, NULL, &size, pci_handle);
 116
 117         if (status == EFI_BUFFER_TOO_SMALL) {
 118                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 119                                      (void **)&pci_handle);
 120
 121                 if (status != EFI_SUCCESS) {
 122                         efi_err("Failed to allocate memory for 'pci_handle'\n");
 123                         return;
 124                 }
 125
 126                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 127                                      &pci_proto, NULL, &size, pci_handle);
 128         }
 129
 130         if (status != EFI_SUCCESS)
 131                 goto free_handle;
 132
 133         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 134
 135         while (data && data->next)
 136                 data = (struct setup_data *)(unsigned long)data->next;
 137
 138         for_each_efi_handle(h, pci_handle, size, i) {
 139                 efi_pci_io_protocol_t *pci = NULL;
 140                 struct pci_setup_rom *rom;
 141
 142                 status = efi_bs_call(handle_protocol, h, &pci_proto,
 143                                      (void **)&pci);
 144                 if (status != EFI_SUCCESS || !pci)
 145                         continue;
 146
 147                 status = preserve_pci_rom_image(pci, &rom);
 148                 if (status != EFI_SUCCESS)
 149                         continue;
 150
 151                 if (data)
 152                         data->next = (unsigned long)rom;
 153                 else
 154                         params->hdr.setup_data = (unsigned long)rom;
 155
 156                 data = (struct setup_data *)rom;
 157         }
 158
 159 free_handle:
 160         efi_bs_call(free_pool, pci_handle);
 161 }
 162
 163 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 164 {
 165         efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 166         struct setup_data *data, *new;
 167         efi_status_t status;
 168         u32 size = 0;
 169         apple_properties_protocol_t *p;
 170
 171         status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 172         if (status != EFI_SUCCESS)
 173                 return;
 174
 175         if (efi_table_attr(p, version) != 0x10000) {
 176                 efi_err("Unsupported properties proto version\n");
 177                 return;
 178         }
 179
 180         efi_call_proto(p, get_all, NULL, &size);
 181         if (!size)
 182                 return;
 183
 184         do {
 185                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 186                                      size + sizeof(struct setup_data),
 187                                      (void **)&new);
 188                 if (status != EFI_SUCCESS) {
 189                         efi_err("Failed to allocate memory for 'properties'\n");
 190                         return;
 191                 }
 192
 193                 status = efi_call_proto(p, get_all, new->data, &size);
 194
 195                 if (status == EFI_BUFFER_TOO_SMALL)
 196                         efi_bs_call(free_pool, new);
 197         } while (status == EFI_BUFFER_TOO_SMALL);
 198
 199         new->type = SETUP_APPLE_PROPERTIES;
 200         new->len  = size;
 201         new->next = 0;
 202
 203         data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 204         if (!data) {
 205                 boot_params->hdr.setup_data = (unsigned long)new;
 206         } else {
 207                 while (data->next)
 208                         data = (struct setup_data *)(unsigned long)data->next;
 209                 data->next = (unsigned long)new;
 210         }
 211 }
 212
 213 static const efi_char16_t apple[] = L"Apple";
 214
 215 static void setup_quirks(struct boot_params *boot_params)
 216 {
 217         efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 218                 efi_table_attr(efi_system_table, fw_vendor);
 219
 220         if (!memcmp(fw_vendor, apple, sizeof(apple))) {
 221                 if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
 222                         retrieve_apple_device_properties(boot_params);
 223         }
 224 }
 225
 226 /*
 227  * See if we have Universal Graphics Adapter (UGA) protocol
 228  */
 229 static efi_status_t
 230 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 231 {
 232         efi_status_t status;
 233         u32 width, height;
 234         void **uga_handle = NULL;
 235         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 236         efi_handle_t handle;
 237         int i;
 238
 239         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 240                              (void **)&uga_handle);
 241         if (status != EFI_SUCCESS)
 242                 return status;
 243
 244         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 245                              uga_proto, NULL, &size, uga_handle);
 246         if (status != EFI_SUCCESS)
 247                 goto free_handle;
 248
 249         height = 0;
 250         width = 0;
 251
 252         first_uga = NULL;
 253         for_each_efi_handle(handle, uga_handle, size, i) {
 254                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 255                 u32 w, h, depth, refresh;
 256                 void *pciio;
 257
 258                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 259                                      (void **)&uga);
 260                 if (status != EFI_SUCCESS)
 261                         continue;
 262
 263                 pciio = NULL;
 264                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 265
 266                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 267                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 268                         width = w;
 269                         height = h;
 270
 271                         /*
 272                          * Once we've found a UGA supporting PCIIO,
 273                          * don't bother looking any further.
 274                          */
 275                         if (pciio)
 276                                 break;
 277
 278                         first_uga = uga;
 279                 }
 280         }
 281
 282         if (!width && !height)
 283                 goto free_handle;
 284
 285         /* EFI framebuffer */
 286         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 287
 288         si->lfb_depth           = 32;
 289         si->lfb_width           = width;
 290         si->lfb_height          = height;
 291
 292         si->red_size            = 8;
 293         si->red_pos             = 16;
 294         si->green_size          = 8;
 295         si->green_pos           = 8;
 296         si->blue_size           = 8;
 297         si->blue_pos            = 0;
 298         si->rsvd_size           = 8;
 299         si->rsvd_pos            = 24;
 300
 301 free_handle:
 302         efi_bs_call(free_pool, uga_handle);
 303
 304         return status;
 305 }
 306
 307 static void setup_graphics(struct boot_params *boot_params)
 308 {
 309         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 310         struct screen_info *si;
 311         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 312         efi_status_t status;
 313         unsigned long size;
 314         void **gop_handle = NULL;
 315         void **uga_handle = NULL;
 316
 317         si = &boot_params->screen_info;
 318         memset(si, 0, sizeof(*si));
 319
 320         size = 0;
 321         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 322                              &graphics_proto, NULL, &size, gop_handle);
 323         if (status == EFI_BUFFER_TOO_SMALL)
 324                 status = efi_setup_gop(si, &graphics_proto, size);
 325
 326         if (status != EFI_SUCCESS) {
 327                 size = 0;
 328                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 329                                      &uga_proto, NULL, &size, uga_handle);
 330                 if (status == EFI_BUFFER_TOO_SMALL)
 331                         setup_uga(si, &uga_proto, size);
 332         }
 333 }
 334
 335
 336 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 337 {
 338         efi_bs_call(exit, handle, status, 0, NULL);
 339         for(;;)
 340                 asm("hlt");
 341 }
 342
 343 void startup_32(struct boot_params *boot_params);
 344
 345 void __noreturn efi_stub_entry(efi_handle_t handle,
 346                                efi_system_table_t *sys_table_arg,
 347                                struct boot_params *boot_params);
 348
 349 /*
 350  * Because the x86 boot code expects to be passed a boot_params we
 351  * need to create one ourselves (usually the bootloader would create
 352  * one for us).
 353  */
 354 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 355                                    efi_system_table_t *sys_table_arg)
 356 {
 357         struct boot_params *boot_params;
 358         struct setup_header *hdr;
 359         void *image_base;
 360         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 361         int options_size = 0;
 362         efi_status_t status;
 363         char *cmdline_ptr;
 364         unsigned long ramdisk_addr;
 365         unsigned long ramdisk_size;
 366
 367         efi_system_table = sys_table_arg;
 368
 369         /* Check if we were booted by the EFI firmware */
 370         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 371                 efi_exit(handle, EFI_INVALID_PARAMETER);
 372
 373         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 374         if (status != EFI_SUCCESS) {
 375                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 376                 efi_exit(handle, status);
 377         }
 378
 379         image_base = efi_table_attr(image, image_base);
 380         image_offset = (void *)startup_32 - image_base;
 381
 382         status = efi_allocate_pages(sizeof(struct boot_params),
 383                                     (unsigned long *)&boot_params, ULONG_MAX);
 384         if (status != EFI_SUCCESS) {
 385                 efi_err("Failed to allocate lowmem for boot params\n");
 386                 efi_exit(handle, status);
 387         }
 388
 389         memset(boot_params, 0x0, sizeof(struct boot_params));
 390
 391         hdr = &boot_params->hdr;
 392
 393         /* Copy the second sector to boot_params */
 394         memcpy(&hdr->jump, image_base + 512, 512);
 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, ULONG_MAX);
 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, buff_size;
 576         struct efi_boot_memmap boot_map;
 577         efi_memory_desc_t *map;
 578         efi_status_t status;
 579         __u32 nr_desc;
 580
 581         boot_map.map            = &map;
 582         boot_map.map_size       = &map_size;
 583         boot_map.desc_size      = &desc_size;
 584         boot_map.desc_ver       = NULL;
 585         boot_map.key_ptr        = NULL;
 586         boot_map.buff_size      = &buff_size;
 587
 588         status = efi_get_memory_map(&boot_map);
 589         if (status != EFI_SUCCESS)
 590                 return status;
 591
 592         nr_desc = buff_size / desc_size;
 593
 594         if (nr_desc > ARRAY_SIZE(params->e820_table)) {
 595                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
 596
 597                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 598                 if (status != EFI_SUCCESS)
 599                         return status;
 600         }
 601
 602         return EFI_SUCCESS;
 603 }
 604
 605 struct exit_boot_struct {
 606         struct boot_params      *boot_params;
 607         struct efi_info         *efi;
 608 };
 609
 610 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 611                                    void *priv)
 612 {
 613         const char *signature;
 614         struct exit_boot_struct *p = priv;
 615
 616         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 617                                    : EFI32_LOADER_SIGNATURE;
 618         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 619
 620         efi_set_u64_split((unsigned long)efi_system_table,
 621                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 622         p->efi->efi_memdesc_size        = *map->desc_size;
 623         p->efi->efi_memdesc_version     = *map->desc_ver;
 624         efi_set_u64_split((unsigned long)*map->map,
 625                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 626         p->efi->efi_memmap_size         = *map->map_size;
 627
 628         return EFI_SUCCESS;
 629 }
 630
 631 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 632 {
 633         unsigned long map_sz, key, desc_size, buff_size;
 634         efi_memory_desc_t *mem_map;
 635         struct setup_data *e820ext = NULL;
 636         __u32 e820ext_size = 0;
 637         efi_status_t status;
 638         __u32 desc_version;
 639         struct efi_boot_memmap map;
 640         struct exit_boot_struct priv;
 641
 642         map.map                 = &mem_map;
 643         map.map_size            = &map_sz;
 644         map.desc_size           = &desc_size;
 645         map.desc_ver            = &desc_version;
 646         map.key_ptr             = &key;
 647         map.buff_size           = &buff_size;
 648         priv.boot_params        = boot_params;
 649         priv.efi                = &boot_params->efi_info;
 650
 651         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 652         if (status != EFI_SUCCESS)
 653                 return status;
 654
 655         /* Might as well exit boot services now */
 656         status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
 657         if (status != EFI_SUCCESS)
 658                 return status;
 659
 660         /* Historic? */
 661         boot_params->alt_mem_k  = 32 * 1024;
 662
 663         status = setup_e820(boot_params, e820ext, e820ext_size);
 664         if (status != EFI_SUCCESS)
 665                 return status;
 666
 667         return EFI_SUCCESS;
 668 }
 669
 670 /*
 671  * On success, we return the address of startup_32, which has potentially been
 672  * relocated by efi_relocate_kernel.
 673  * On failure, we exit to the firmware via efi_exit instead of returning.
 674  */
 675 unsigned long efi_main(efi_handle_t handle,
 676                              efi_system_table_t *sys_table_arg,
 677                              struct boot_params *boot_params)
 678 {
 679         unsigned long bzimage_addr = (unsigned long)startup_32;
 680         unsigned long buffer_start, buffer_end;
 681         struct setup_header *hdr = &boot_params->hdr;
 682         efi_status_t status;
 683         unsigned long cmdline_paddr;
 684
 685         efi_system_table = sys_table_arg;
 686
 687         /* Check if we were booted by the EFI firmware */
 688         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 689                 efi_exit(handle, EFI_INVALID_PARAMETER);
 690
 691         /*
 692          * If the kernel isn't already loaded at a suitable address,
 693          * relocate it.
 694          *
 695          * It must be loaded above LOAD_PHYSICAL_ADDR.
 696          *
 697          * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
 698          * is defined as the macro MAXMEM, but unfortunately that is not a
 699          * compile-time constant if 5-level paging is configured, so we instead
 700          * define our own macro for use here.
 701          *
 702          * For 32-bit, the maximum address is complicated to figure out, for
 703          * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
 704          * KASLR uses.
 705          *
 706          * Also relocate it if image_offset is zero, i.e. the kernel wasn't
 707          * loaded by LoadImage, but rather by a bootloader that called the
 708          * handover entry. The reason we must always relocate in this case is
 709          * to handle the case of systemd-boot booting a unified kernel image,
 710          * which is a PE executable that contains the bzImage and an initrd as
 711          * COFF sections. The initrd section is placed after the bzImage
 712          * without ensuring that there are at least init_size bytes available
 713          * for the bzImage, and thus the compressed kernel's startup code may
 714          * overwrite the initrd unless it is moved out of the way.
 715          */
 716
 717         buffer_start = ALIGN(bzimage_addr - image_offset,
 718                              hdr->kernel_alignment);
 719         buffer_end = buffer_start + hdr->init_size;
 720
 721         if ((buffer_start < LOAD_PHYSICAL_ADDR)                              ||
 722             (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE)    ||
 723             (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
 724             (image_offset == 0)) {
 725                 status = efi_relocate_kernel(&bzimage_addr,
 726                                              hdr->init_size, hdr->init_size,
 727                                              hdr->pref_address,
 728                                              hdr->kernel_alignment,
 729                                              LOAD_PHYSICAL_ADDR);
 730                 if (status != EFI_SUCCESS) {
 731                         efi_err("efi_relocate_kernel() failed!\n");
 732                         goto fail;
 733                 }
 734                 /*
 735                  * Now that we've copied the kernel elsewhere, we no longer
 736                  * have a set up block before startup_32(), so reset image_offset
 737                  * to zero in case it was set earlier.
 738                  */
 739                 image_offset = 0;
 740         }
 741
 742         cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 743                          ((u64)boot_params->ext_cmd_line_ptr << 32));
 744         efi_parse_options((char *)cmdline_paddr);
 745
 746         /*
 747          * At this point, an initrd may already have been loaded by the
 748          * bootloader and passed via bootparams. We permit an initrd loaded
 749          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 750          *
 751          * If the device path is not present, any command-line initrd=
 752          * arguments will be processed only if image is not NULL, which will be
 753          * the case only if we were loaded via the PE entry point.
 754          */
 755         if (!efi_noinitrd) {
 756                 unsigned long addr, size;
 757
 758                 status = efi_load_initrd_dev_path(&addr, &size, ULONG_MAX);
 759                 if (status == EFI_NOT_FOUND) {
 760                         if (efi_is_native() && image != NULL) {
 761                                 status = efi_load_initrd(image, &addr, &size,
 762                                                          hdr->initrd_addr_max,
 763                                                          ULONG_MAX);
 764                         } else {
 765                                 addr = size = 0;
 766                                 status = EFI_SUCCESS;
 767                         }
 768                 }
 769
 770                 if (status != EFI_SUCCESS) {
 771                         efi_err("Failed to load initrd!\n");
 772                         goto fail;
 773                 }
 774                 efi_set_u64_split(addr, &hdr->ramdisk_image,
 775                                   &boot_params->ext_ramdisk_image);
 776                 efi_set_u64_split(size, &hdr->ramdisk_size,
 777                                   &boot_params->ext_ramdisk_size);
 778         }
 779
 780         /*
 781          * If the boot loader gave us a value for secure_boot then we use that,
 782          * otherwise we ask the BIOS.
 783          */
 784         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 785                 boot_params->secure_boot = efi_get_secureboot();
 786
 787         /* Ask the firmware to clear memory on unclean shutdown */
 788         efi_enable_reset_attack_mitigation();
 789
 790         efi_random_get_seed();
 791
 792         efi_retrieve_tpm2_eventlog();
 793
 794         setup_graphics(boot_params);
 795
 796         setup_efi_pci(boot_params);
 797
 798         setup_quirks(boot_params);
 799
 800         status = exit_boot(boot_params, handle);
 801         if (status != EFI_SUCCESS) {
 802                 efi_err("exit_boot() failed!\n");
 803                 goto fail;
 804         }
 805
 806         return bzimage_addr;
 807 fail:
 808         efi_err("efi_main() failed!\n");
 809
 810         efi_exit(handle, status);
 811 }