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 #include "x86-stub.h"
  21
  22 /* Maximum physical address for 64-bit kernel with 4-level paging */
  23 #define MAXMEM_X86_64_4LEVEL (1ull << 46)
  24
  25 const efi_system_table_t *efi_system_table;
  26 const efi_dxe_services_table_t *efi_dxe_table;
  27 u32 image_offset __section(".data");
  28 static efi_loaded_image_t *image = NULL;
  29
  30 typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
  31 union sev_memory_acceptance_protocol {
  32         struct {
  33                 efi_status_t (__efiapi * allow_unaccepted_memory)(
  34                         sev_memory_acceptance_protocol_t *);
  35         };
  36         struct {
  37                 u32 allow_unaccepted_memory;
  38         } mixed_mode;
  39 };
  40
  41 static efi_status_t
  42 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
  43 {
  44         struct pci_setup_rom *rom = NULL;
  45         efi_status_t status;
  46         unsigned long size;
  47         uint64_t romsize;
  48         void *romimage;
  49
  50         /*
  51          * Some firmware images contain EFI function pointers at the place where
  52          * the romimage and romsize fields are supposed to be. Typically the EFI
  53          * code is mapped at high addresses, translating to an unrealistically
  54          * large romsize. The UEFI spec limits the size of option ROMs to 16
  55          * MiB so we reject any ROMs over 16 MiB in size to catch this.
  56          */
  57         romimage = efi_table_attr(pci, romimage);
  58         romsize = efi_table_attr(pci, romsize);
  59         if (!romimage || !romsize || romsize > SZ_16M)
  60                 return EFI_INVALID_PARAMETER;
  61
  62         size = romsize + sizeof(*rom);
  63
  64         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
  65                              (void **)&rom);
  66         if (status != EFI_SUCCESS) {
  67                 efi_err("Failed to allocate memory for 'rom'\n");
  68                 return status;
  69         }
  70
  71         memset(rom, 0, sizeof(*rom));
  72
  73         rom->data.type  = SETUP_PCI;
  74         rom->data.len   = size - sizeof(struct setup_data);
  75         rom->data.next  = 0;
  76         rom->pcilen     = pci->romsize;
  77         *__rom = rom;
  78
  79         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  80                                 PCI_VENDOR_ID, 1, &rom->vendor);
  81
  82         if (status != EFI_SUCCESS) {
  83                 efi_err("Failed to read rom->vendor\n");
  84                 goto free_struct;
  85         }
  86
  87         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  88                                 PCI_DEVICE_ID, 1, &rom->devid);
  89
  90         if (status != EFI_SUCCESS) {
  91                 efi_err("Failed to read rom->devid\n");
  92                 goto free_struct;
  93         }
  94
  95         status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
  96                                 &rom->device, &rom->function);
  97
  98         if (status != EFI_SUCCESS)
  99                 goto free_struct;
 100
 101         memcpy(rom->romdata, romimage, romsize);
 102         return status;
 103
 104 free_struct:
 105         efi_bs_call(free_pool, rom);
 106         return status;
 107 }
 108
 109 /*
 110  * There's no way to return an informative status from this function,
 111  * because any analysis (and printing of error messages) needs to be
 112  * done directly at the EFI function call-site.
 113  *
 114  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 115  * just didn't find any PCI devices, but there's no way to tell outside
 116  * the context of the call.
 117  */
 118 static void setup_efi_pci(struct boot_params *params)
 119 {
 120         efi_status_t status;
 121         void **pci_handle = NULL;
 122         efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 123         unsigned long size = 0;
 124         struct setup_data *data;
 125         efi_handle_t h;
 126         int i;
 127
 128         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 129                              &pci_proto, NULL, &size, pci_handle);
 130
 131         if (status == EFI_BUFFER_TOO_SMALL) {
 132                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 133                                      (void **)&pci_handle);
 134
 135                 if (status != EFI_SUCCESS) {
 136                         efi_err("Failed to allocate memory for 'pci_handle'\n");
 137                         return;
 138                 }
 139
 140                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 141                                      &pci_proto, NULL, &size, pci_handle);
 142         }
 143
 144         if (status != EFI_SUCCESS)
 145                 goto free_handle;
 146
 147         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 148
 149         while (data && data->next)
 150                 data = (struct setup_data *)(unsigned long)data->next;
 151
 152         for_each_efi_handle(h, pci_handle, size, i) {
 153                 efi_pci_io_protocol_t *pci = NULL;
 154                 struct pci_setup_rom *rom;
 155
 156                 status = efi_bs_call(handle_protocol, h, &pci_proto,
 157                                      (void **)&pci);
 158                 if (status != EFI_SUCCESS || !pci)
 159                         continue;
 160
 161                 status = preserve_pci_rom_image(pci, &rom);
 162                 if (status != EFI_SUCCESS)
 163                         continue;
 164
 165                 if (data)
 166                         data->next = (unsigned long)rom;
 167                 else
 168                         params->hdr.setup_data = (unsigned long)rom;
 169
 170                 data = (struct setup_data *)rom;
 171         }
 172
 173 free_handle:
 174         efi_bs_call(free_pool, pci_handle);
 175 }
 176
 177 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 178 {
 179         efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 180         struct setup_data *data, *new;
 181         efi_status_t status;
 182         u32 size = 0;
 183         apple_properties_protocol_t *p;
 184
 185         status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 186         if (status != EFI_SUCCESS)
 187                 return;
 188
 189         if (efi_table_attr(p, version) != 0x10000) {
 190                 efi_err("Unsupported properties proto version\n");
 191                 return;
 192         }
 193
 194         efi_call_proto(p, get_all, NULL, &size);
 195         if (!size)
 196                 return;
 197
 198         do {
 199                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 200                                      size + sizeof(struct setup_data),
 201                                      (void **)&new);
 202                 if (status != EFI_SUCCESS) {
 203                         efi_err("Failed to allocate memory for 'properties'\n");
 204                         return;
 205                 }
 206
 207                 status = efi_call_proto(p, get_all, new->data, &size);
 208
 209                 if (status == EFI_BUFFER_TOO_SMALL)
 210                         efi_bs_call(free_pool, new);
 211         } while (status == EFI_BUFFER_TOO_SMALL);
 212
 213         new->type = SETUP_APPLE_PROPERTIES;
 214         new->len  = size;
 215         new->next = 0;
 216
 217         data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 218         if (!data) {
 219                 boot_params->hdr.setup_data = (unsigned long)new;
 220         } else {
 221                 while (data->next)
 222                         data = (struct setup_data *)(unsigned long)data->next;
 223                 data->next = (unsigned long)new;
 224         }
 225 }
 226
 227 void efi_adjust_memory_range_protection(unsigned long start,
 228                                         unsigned long size)
 229 {
 230         efi_status_t status;
 231         efi_gcd_memory_space_desc_t desc;
 232         unsigned long end, next;
 233         unsigned long rounded_start, rounded_end;
 234         unsigned long unprotect_start, unprotect_size;
 235
 236         if (efi_dxe_table == NULL)
 237                 return;
 238
 239         rounded_start = rounddown(start, EFI_PAGE_SIZE);
 240         rounded_end = roundup(start + size, EFI_PAGE_SIZE);
 241
 242         /*
 243          * Don't modify memory region attributes, they are
 244          * already suitable, to lower the possibility to
 245          * encounter firmware bugs.
 246          */
 247
 248         for (end = start + size; start < end; start = next) {
 249
 250                 status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
 251
 252                 if (status != EFI_SUCCESS)
 253                         return;
 254
 255                 next = desc.base_address + desc.length;
 256
 257                 /*
 258                  * Only system memory is suitable for trampoline/kernel image placement,
 259                  * so only this type of memory needs its attributes to be modified.
 260                  */
 261
 262                 if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
 263                     (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
 264                         continue;
 265
 266                 unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
 267                 unprotect_size = min(rounded_end, next) - unprotect_start;
 268
 269                 status = efi_dxe_call(set_memory_space_attributes,
 270                                       unprotect_start, unprotect_size,
 271                                       EFI_MEMORY_WB);
 272
 273                 if (status != EFI_SUCCESS) {
 274                         efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
 275                                  unprotect_start,
 276                                  unprotect_start + unprotect_size,
 277                                  status);
 278                 }
 279         }
 280 }
 281
 282 extern const u8 startup_32[], startup_64[];
 283
 284 static void
 285 setup_memory_protection(unsigned long image_base, unsigned long image_size)
 286 {
 287 #ifdef CONFIG_64BIT
 288         if (image_base != (unsigned long)startup_32)
 289                 efi_adjust_memory_range_protection(image_base, image_size);
 290 #else
 291         /*
 292          * Clear protection flags on a whole range of possible
 293          * addresses used for KASLR. We don't need to do that
 294          * on x86_64, since KASLR/extraction is performed after
 295          * dedicated identity page tables are built and we only
 296          * need to remove possible protection on relocated image
 297          * itself disregarding further relocations.
 298          */
 299         efi_adjust_memory_range_protection(LOAD_PHYSICAL_ADDR,
 300                                            KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR);
 301 #endif
 302 }
 303
 304 static void setup_unaccepted_memory(void)
 305 {
 306         efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
 307         sev_memory_acceptance_protocol_t *proto;
 308         efi_status_t status;
 309
 310         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 311                 return;
 312
 313         /*
 314          * Enable unaccepted memory before calling exit boot services in order
 315          * for the UEFI to not accept all memory on EBS.
 316          */
 317         status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
 318                              (void **)&proto);
 319         if (status != EFI_SUCCESS)
 320                 return;
 321
 322         status = efi_call_proto(proto, allow_unaccepted_memory);
 323         if (status != EFI_SUCCESS)
 324                 efi_err("Memory acceptance protocol failed\n");
 325 }
 326
 327 static const efi_char16_t apple[] = L"Apple";
 328
 329 static void setup_quirks(struct boot_params *boot_params,
 330                          unsigned long image_base,
 331                          unsigned long image_size)
 332 {
 333         efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 334                 efi_table_attr(efi_system_table, fw_vendor);
 335
 336         if (!memcmp(fw_vendor, apple, sizeof(apple))) {
 337                 if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
 338                         retrieve_apple_device_properties(boot_params);
 339         }
 340
 341         if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES))
 342                 setup_memory_protection(image_base, image_size);
 343 }
 344
 345 /*
 346  * See if we have Universal Graphics Adapter (UGA) protocol
 347  */
 348 static efi_status_t
 349 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 350 {
 351         efi_status_t status;
 352         u32 width, height;
 353         void **uga_handle = NULL;
 354         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 355         efi_handle_t handle;
 356         int i;
 357
 358         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 359                              (void **)&uga_handle);
 360         if (status != EFI_SUCCESS)
 361                 return status;
 362
 363         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 364                              uga_proto, NULL, &size, uga_handle);
 365         if (status != EFI_SUCCESS)
 366                 goto free_handle;
 367
 368         height = 0;
 369         width = 0;
 370
 371         first_uga = NULL;
 372         for_each_efi_handle(handle, uga_handle, size, i) {
 373                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 374                 u32 w, h, depth, refresh;
 375                 void *pciio;
 376
 377                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 378                                      (void **)&uga);
 379                 if (status != EFI_SUCCESS)
 380                         continue;
 381
 382                 pciio = NULL;
 383                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 384
 385                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 386                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 387                         width = w;
 388                         height = h;
 389
 390                         /*
 391                          * Once we've found a UGA supporting PCIIO,
 392                          * don't bother looking any further.
 393                          */
 394                         if (pciio)
 395                                 break;
 396
 397                         first_uga = uga;
 398                 }
 399         }
 400
 401         if (!width && !height)
 402                 goto free_handle;
 403
 404         /* EFI framebuffer */
 405         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 406
 407         si->lfb_depth           = 32;
 408         si->lfb_width           = width;
 409         si->lfb_height          = height;
 410
 411         si->red_size            = 8;
 412         si->red_pos             = 16;
 413         si->green_size          = 8;
 414         si->green_pos           = 8;
 415         si->blue_size           = 8;
 416         si->blue_pos            = 0;
 417         si->rsvd_size           = 8;
 418         si->rsvd_pos            = 24;
 419
 420 free_handle:
 421         efi_bs_call(free_pool, uga_handle);
 422
 423         return status;
 424 }
 425
 426 static void setup_graphics(struct boot_params *boot_params)
 427 {
 428         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 429         struct screen_info *si;
 430         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 431         efi_status_t status;
 432         unsigned long size;
 433         void **gop_handle = NULL;
 434         void **uga_handle = NULL;
 435
 436         si = &boot_params->screen_info;
 437         memset(si, 0, sizeof(*si));
 438
 439         size = 0;
 440         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 441                              &graphics_proto, NULL, &size, gop_handle);
 442         if (status == EFI_BUFFER_TOO_SMALL)
 443                 status = efi_setup_gop(si, &graphics_proto, size);
 444
 445         if (status != EFI_SUCCESS) {
 446                 size = 0;
 447                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 448                                      &uga_proto, NULL, &size, uga_handle);
 449                 if (status == EFI_BUFFER_TOO_SMALL)
 450                         setup_uga(si, &uga_proto, size);
 451         }
 452 }
 453
 454
 455 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 456 {
 457         efi_bs_call(exit, handle, status, 0, NULL);
 458         for(;;)
 459                 asm("hlt");
 460 }
 461
 462 void __noreturn efi_stub_entry(efi_handle_t handle,
 463                                efi_system_table_t *sys_table_arg,
 464                                struct boot_params *boot_params);
 465
 466 /*
 467  * Because the x86 boot code expects to be passed a boot_params we
 468  * need to create one ourselves (usually the bootloader would create
 469  * one for us).
 470  */
 471 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 472                                    efi_system_table_t *sys_table_arg)
 473 {
 474         struct boot_params *boot_params;
 475         struct setup_header *hdr;
 476         void *image_base;
 477         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 478         int options_size = 0;
 479         efi_status_t status;
 480         char *cmdline_ptr;
 481
 482         efi_system_table = sys_table_arg;
 483
 484         /* Check if we were booted by the EFI firmware */
 485         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 486                 efi_exit(handle, EFI_INVALID_PARAMETER);
 487
 488         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 489         if (status != EFI_SUCCESS) {
 490                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 491                 efi_exit(handle, status);
 492         }
 493
 494         image_base = efi_table_attr(image, image_base);
 495         image_offset = (void *)startup_32 - image_base;
 496
 497         status = efi_allocate_pages(sizeof(struct boot_params),
 498                                     (unsigned long *)&boot_params, ULONG_MAX);
 499         if (status != EFI_SUCCESS) {
 500                 efi_err("Failed to allocate lowmem for boot params\n");
 501                 efi_exit(handle, status);
 502         }
 503
 504         memset(boot_params, 0x0, sizeof(struct boot_params));
 505
 506         hdr = &boot_params->hdr;
 507
 508         /* Copy the setup header from the second sector to boot_params */
 509         memcpy(&hdr->jump, image_base + 512,
 510                sizeof(struct setup_header) - offsetof(struct setup_header, jump));
 511
 512         /*
 513          * Fill out some of the header fields ourselves because the
 514          * EFI firmware loader doesn't load the first sector.
 515          */
 516         hdr->root_flags = 1;
 517         hdr->vid_mode   = 0xffff;
 518         hdr->boot_flag  = 0xAA55;
 519
 520         hdr->type_of_loader = 0x21;
 521
 522         /* Convert unicode cmdline to ascii */
 523         cmdline_ptr = efi_convert_cmdline(image, &options_size);
 524         if (!cmdline_ptr)
 525                 goto fail;
 526
 527         efi_set_u64_split((unsigned long)cmdline_ptr,
 528                           &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);
 529
 530         hdr->ramdisk_image = 0;
 531         hdr->ramdisk_size = 0;
 532
 533         /*
 534          * Disregard any setup data that was provided by the bootloader:
 535          * setup_data could be pointing anywhere, and we have no way of
 536          * authenticating or validating the payload.
 537          */
 538         hdr->setup_data = 0;
 539
 540         efi_stub_entry(handle, sys_table_arg, boot_params);
 541         /* not reached */
 542
 543 fail:
 544         efi_free(sizeof(struct boot_params), (unsigned long)boot_params);
 545
 546         efi_exit(handle, status);
 547 }
 548
 549 static void add_e820ext(struct boot_params *params,
 550                         struct setup_data *e820ext, u32 nr_entries)
 551 {
 552         struct setup_data *data;
 553
 554         e820ext->type = SETUP_E820_EXT;
 555         e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 556         e820ext->next = 0;
 557
 558         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 559
 560         while (data && data->next)
 561                 data = (struct setup_data *)(unsigned long)data->next;
 562
 563         if (data)
 564                 data->next = (unsigned long)e820ext;
 565         else
 566                 params->hdr.setup_data = (unsigned long)e820ext;
 567 }
 568
 569 static efi_status_t
 570 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 571 {
 572         struct boot_e820_entry *entry = params->e820_table;
 573         struct efi_info *efi = &params->efi_info;
 574         struct boot_e820_entry *prev = NULL;
 575         u32 nr_entries;
 576         u32 nr_desc;
 577         int i;
 578
 579         nr_entries = 0;
 580         nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
 581
 582         for (i = 0; i < nr_desc; i++) {
 583                 efi_memory_desc_t *d;
 584                 unsigned int e820_type = 0;
 585                 unsigned long m = efi->efi_memmap;
 586
 587 #ifdef CONFIG_X86_64
 588                 m |= (u64)efi->efi_memmap_hi << 32;
 589 #endif
 590
 591                 d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 592                 switch (d->type) {
 593                 case EFI_RESERVED_TYPE:
 594                 case EFI_RUNTIME_SERVICES_CODE:
 595                 case EFI_RUNTIME_SERVICES_DATA:
 596                 case EFI_MEMORY_MAPPED_IO:
 597                 case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 598                 case EFI_PAL_CODE:
 599                         e820_type = E820_TYPE_RESERVED;
 600                         break;
 601
 602                 case EFI_UNUSABLE_MEMORY:
 603                         e820_type = E820_TYPE_UNUSABLE;
 604                         break;
 605
 606                 case EFI_ACPI_RECLAIM_MEMORY:
 607                         e820_type = E820_TYPE_ACPI;
 608                         break;
 609
 610                 case EFI_LOADER_CODE:
 611                 case EFI_LOADER_DATA:
 612                 case EFI_BOOT_SERVICES_CODE:
 613                 case EFI_BOOT_SERVICES_DATA:
 614                 case EFI_CONVENTIONAL_MEMORY:
 615                         if (efi_soft_reserve_enabled() &&
 616                             (d->attribute & EFI_MEMORY_SP))
 617                                 e820_type = E820_TYPE_SOFT_RESERVED;
 618                         else
 619                                 e820_type = E820_TYPE_RAM;
 620                         break;
 621
 622                 case EFI_ACPI_MEMORY_NVS:
 623                         e820_type = E820_TYPE_NVS;
 624                         break;
 625
 626                 case EFI_PERSISTENT_MEMORY:
 627                         e820_type = E820_TYPE_PMEM;
 628                         break;
 629
 630                 case EFI_UNACCEPTED_MEMORY:
 631                         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) {
 632                                 efi_warn_once(
 633 "The system has unaccepted memory,  but kernel does not support it\nConsider enabling CONFIG_UNACCEPTED_MEMORY\n");
 634                                 continue;
 635                         }
 636                         e820_type = E820_TYPE_RAM;
 637                         process_unaccepted_memory(d->phys_addr,
 638                                                   d->phys_addr + PAGE_SIZE * d->num_pages);
 639                         break;
 640                 default:
 641                         continue;
 642                 }
 643
 644                 /* Merge adjacent mappings */
 645                 if (prev && prev->type == e820_type &&
 646                     (prev->addr + prev->size) == d->phys_addr) {
 647                         prev->size += d->num_pages << 12;
 648                         continue;
 649                 }
 650
 651                 if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 652                         u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 653                                    sizeof(struct setup_data);
 654
 655                         if (!e820ext || e820ext_size < need)
 656                                 return EFI_BUFFER_TOO_SMALL;
 657
 658                         /* boot_params map full, switch to e820 extended */
 659                         entry = (struct boot_e820_entry *)e820ext->data;
 660                 }
 661
 662                 entry->addr = d->phys_addr;
 663                 entry->size = d->num_pages << PAGE_SHIFT;
 664                 entry->type = e820_type;
 665                 prev = entry++;
 666                 nr_entries++;
 667         }
 668
 669         if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 670                 u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
 671
 672                 add_e820ext(params, e820ext, nr_e820ext);
 673                 nr_entries -= nr_e820ext;
 674         }
 675
 676         params->e820_entries = (u8)nr_entries;
 677
 678         return EFI_SUCCESS;
 679 }
 680
 681 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 682                                   u32 *e820ext_size)
 683 {
 684         efi_status_t status;
 685         unsigned long size;
 686
 687         size = sizeof(struct setup_data) +
 688                 sizeof(struct e820_entry) * nr_desc;
 689
 690         if (*e820ext) {
 691                 efi_bs_call(free_pool, *e820ext);
 692                 *e820ext = NULL;
 693                 *e820ext_size = 0;
 694         }
 695
 696         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 697                              (void **)e820ext);
 698         if (status == EFI_SUCCESS)
 699                 *e820ext_size = size;
 700
 701         return status;
 702 }
 703
 704 static efi_status_t allocate_e820(struct boot_params *params,
 705                                   struct setup_data **e820ext,
 706                                   u32 *e820ext_size)
 707 {
 708         struct efi_boot_memmap *map;
 709         efi_status_t status;
 710         __u32 nr_desc;
 711
 712         status = efi_get_memory_map(&map, false);
 713         if (status != EFI_SUCCESS)
 714                 return status;
 715
 716         nr_desc = map->map_size / map->desc_size;
 717         if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
 718                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
 719                                  EFI_MMAP_NR_SLACK_SLOTS;
 720
 721                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 722         }
 723
 724         if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
 725                 status = allocate_unaccepted_bitmap(nr_desc, map);
 726
 727         efi_bs_call(free_pool, map);
 728         return status;
 729 }
 730
 731 struct exit_boot_struct {
 732         struct boot_params      *boot_params;
 733         struct efi_info         *efi;
 734 };
 735
 736 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 737                                    void *priv)
 738 {
 739         const char *signature;
 740         struct exit_boot_struct *p = priv;
 741
 742         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 743                                    : EFI32_LOADER_SIGNATURE;
 744         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 745
 746         efi_set_u64_split((unsigned long)efi_system_table,
 747                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 748         p->efi->efi_memdesc_size        = map->desc_size;
 749         p->efi->efi_memdesc_version     = map->desc_ver;
 750         efi_set_u64_split((unsigned long)map->map,
 751                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 752         p->efi->efi_memmap_size         = map->map_size;
 753
 754         return EFI_SUCCESS;
 755 }
 756
 757 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 758 {
 759         struct setup_data *e820ext = NULL;
 760         __u32 e820ext_size = 0;
 761         efi_status_t status;
 762         struct exit_boot_struct priv;
 763
 764         priv.boot_params        = boot_params;
 765         priv.efi                = &boot_params->efi_info;
 766
 767         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 768         if (status != EFI_SUCCESS)
 769                 return status;
 770
 771         /* Might as well exit boot services now */
 772         status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 773         if (status != EFI_SUCCESS)
 774                 return status;
 775
 776         /* Historic? */
 777         boot_params->alt_mem_k  = 32 * 1024;
 778
 779         status = setup_e820(boot_params, e820ext, e820ext_size);
 780         if (status != EFI_SUCCESS)
 781                 return status;
 782
 783         return EFI_SUCCESS;
 784 }
 785
 786 static void __noreturn enter_kernel(unsigned long kernel_addr,
 787                                     struct boot_params *boot_params)
 788 {
 789         /* enter decompressed kernel with boot_params pointer in RSI/ESI */
 790         asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
 791
 792         unreachable();
 793 }
 794
 795 /*
 796  * On success, this routine will jump to the relocated image directly and never
 797  * return.  On failure, it will exit to the firmware via efi_exit() instead of
 798  * returning.
 799  */
 800 void __noreturn efi_stub_entry(efi_handle_t handle,
 801                                efi_system_table_t *sys_table_arg,
 802                                struct boot_params *boot_params)
 803 {
 804         unsigned long bzimage_addr = (unsigned long)startup_32;
 805         unsigned long buffer_start, buffer_end;
 806         struct setup_header *hdr = &boot_params->hdr;
 807         const struct linux_efi_initrd *initrd = NULL;
 808         efi_status_t status;
 809
 810         efi_system_table = sys_table_arg;
 811         /* Check if we were booted by the EFI firmware */
 812         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 813                 efi_exit(handle, EFI_INVALID_PARAMETER);
 814
 815         efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
 816         if (efi_dxe_table &&
 817             efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
 818                 efi_warn("Ignoring DXE services table: invalid signature\n");
 819                 efi_dxe_table = NULL;
 820         }
 821
 822         status = efi_setup_5level_paging();
 823         if (status != EFI_SUCCESS) {
 824                 efi_err("efi_setup_5level_paging() failed!\n");
 825                 goto fail;
 826         }
 827
 828         /*
 829          * If the kernel isn't already loaded at a suitable address,
 830          * relocate it.
 831          *
 832          * It must be loaded above LOAD_PHYSICAL_ADDR.
 833          *
 834          * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
 835          * is defined as the macro MAXMEM, but unfortunately that is not a
 836          * compile-time constant if 5-level paging is configured, so we instead
 837          * define our own macro for use here.
 838          *
 839          * For 32-bit, the maximum address is complicated to figure out, for
 840          * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
 841          * KASLR uses.
 842          *
 843          * Also relocate it if image_offset is zero, i.e. the kernel wasn't
 844          * loaded by LoadImage, but rather by a bootloader that called the
 845          * handover entry. The reason we must always relocate in this case is
 846          * to handle the case of systemd-boot booting a unified kernel image,
 847          * which is a PE executable that contains the bzImage and an initrd as
 848          * COFF sections. The initrd section is placed after the bzImage
 849          * without ensuring that there are at least init_size bytes available
 850          * for the bzImage, and thus the compressed kernel's startup code may
 851          * overwrite the initrd unless it is moved out of the way.
 852          */
 853
 854         buffer_start = ALIGN(bzimage_addr - image_offset,
 855                              hdr->kernel_alignment);
 856         buffer_end = buffer_start + hdr->init_size;
 857
 858         if ((buffer_start < LOAD_PHYSICAL_ADDR)                              ||
 859             (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE)    ||
 860             (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
 861             (image_offset == 0)) {
 862                 extern char _bss[];
 863
 864                 status = efi_relocate_kernel(&bzimage_addr,
 865                                              (unsigned long)_bss - bzimage_addr,
 866                                              hdr->init_size,
 867                                              hdr->pref_address,
 868                                              hdr->kernel_alignment,
 869                                              LOAD_PHYSICAL_ADDR);
 870                 if (status != EFI_SUCCESS) {
 871                         efi_err("efi_relocate_kernel() failed!\n");
 872                         goto fail;
 873                 }
 874                 /*
 875                  * Now that we've copied the kernel elsewhere, we no longer
 876                  * have a set up block before startup_32(), so reset image_offset
 877                  * to zero in case it was set earlier.
 878                  */
 879                 image_offset = 0;
 880         }
 881
 882 #ifdef CONFIG_CMDLINE_BOOL
 883         status = efi_parse_options(CONFIG_CMDLINE);
 884         if (status != EFI_SUCCESS) {
 885                 efi_err("Failed to parse options\n");
 886                 goto fail;
 887         }
 888 #endif
 889         if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 890                 unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 891                                                ((u64)boot_params->ext_cmd_line_ptr << 32));
 892                 status = efi_parse_options((char *)cmdline_paddr);
 893                 if (status != EFI_SUCCESS) {
 894                         efi_err("Failed to parse options\n");
 895                         goto fail;
 896                 }
 897         }
 898
 899         /*
 900          * At this point, an initrd may already have been loaded by the
 901          * bootloader and passed via bootparams. We permit an initrd loaded
 902          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 903          *
 904          * If the device path is not present, any command-line initrd=
 905          * arguments will be processed only if image is not NULL, which will be
 906          * the case only if we were loaded via the PE entry point.
 907          */
 908         status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
 909                                  &initrd);
 910         if (status != EFI_SUCCESS)
 911                 goto fail;
 912         if (initrd && initrd->size > 0) {
 913                 efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
 914                                   &boot_params->ext_ramdisk_image);
 915                 efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
 916                                   &boot_params->ext_ramdisk_size);
 917         }
 918
 919
 920         /*
 921          * If the boot loader gave us a value for secure_boot then we use that,
 922          * otherwise we ask the BIOS.
 923          */
 924         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 925                 boot_params->secure_boot = efi_get_secureboot();
 926
 927         /* Ask the firmware to clear memory on unclean shutdown */
 928         efi_enable_reset_attack_mitigation();
 929
 930         efi_random_get_seed();
 931
 932         efi_retrieve_tpm2_eventlog();
 933
 934         setup_graphics(boot_params);
 935
 936         setup_efi_pci(boot_params);
 937
 938         setup_quirks(boot_params, bzimage_addr, buffer_end - buffer_start);
 939
 940         setup_unaccepted_memory();
 941
 942         status = exit_boot(boot_params, handle);
 943         if (status != EFI_SUCCESS) {
 944                 efi_err("exit_boot() failed!\n");
 945                 goto fail;
 946         }
 947
 948         efi_5level_switch();
 949
 950         if (IS_ENABLED(CONFIG_X86_64))
 951                 bzimage_addr += startup_64 - startup_32;
 952
 953         enter_kernel(bzimage_addr, boot_params);
 954 fail:
 955         efi_err("efi_stub_entry() failed!\n");
 956
 957         efi_exit(handle, status);
 958 }
 959
 960 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
 961 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 962                         struct boot_params *boot_params)
 963 {
 964         extern char _bss[], _ebss[];
 965
 966         memset(_bss, 0, _ebss - _bss);
 967         efi_stub_entry(handle, sys_table_arg, boot_params);
 968 }
 969
 970 #ifndef CONFIG_EFI_MIXED
 971 extern __alias(efi_handover_entry)
 972 void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 973                       struct boot_params *boot_params);
 974
 975 extern __alias(efi_handover_entry)
 976 void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 977                       struct boot_params *boot_params);
 978 #endif
 979 #endif