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 #include <asm/kaslr.h>
  19 #include <asm/sev.h>
  20
  21 #include "efistub.h"
  22 #include "x86-stub.h"
  23
  24 const efi_system_table_t *efi_system_table;
  25 const efi_dxe_services_table_t *efi_dxe_table;
  26 static efi_loaded_image_t *image = NULL;
  27 static efi_memory_attribute_protocol_t *memattr;
  28
  29 typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
  30 union sev_memory_acceptance_protocol {
  31         struct {
  32                 efi_status_t (__efiapi * allow_unaccepted_memory)(
  33                         sev_memory_acceptance_protocol_t *);
  34         };
  35         struct {
  36                 u32 allow_unaccepted_memory;
  37         } mixed_mode;
  38 };
  39
  40 static efi_status_t
  41 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
  42 {
  43         struct pci_setup_rom *rom = NULL;
  44         efi_status_t status;
  45         unsigned long size;
  46         uint64_t romsize;
  47         void *romimage;
  48
  49         /*
  50          * Some firmware images contain EFI function pointers at the place where
  51          * the romimage and romsize fields are supposed to be. Typically the EFI
  52          * code is mapped at high addresses, translating to an unrealistically
  53          * large romsize. The UEFI spec limits the size of option ROMs to 16
  54          * MiB so we reject any ROMs over 16 MiB in size to catch this.
  55          */
  56         romimage = efi_table_attr(pci, romimage);
  57         romsize = efi_table_attr(pci, romsize);
  58         if (!romimage || !romsize || romsize > SZ_16M)
  59                 return EFI_INVALID_PARAMETER;
  60
  61         size = romsize + sizeof(*rom);
  62
  63         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
  64                              (void **)&rom);
  65         if (status != EFI_SUCCESS) {
  66                 efi_err("Failed to allocate memory for 'rom'\n");
  67                 return status;
  68         }
  69
  70         memset(rom, 0, sizeof(*rom));
  71
  72         rom->data.type  = SETUP_PCI;
  73         rom->data.len   = size - sizeof(struct setup_data);
  74         rom->data.next  = 0;
  75         rom->pcilen     = romsize;
  76         *__rom = rom;
  77
  78         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  79                                 PCI_VENDOR_ID, 1, &rom->vendor);
  80
  81         if (status != EFI_SUCCESS) {
  82                 efi_err("Failed to read rom->vendor\n");
  83                 goto free_struct;
  84         }
  85
  86         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  87                                 PCI_DEVICE_ID, 1, &rom->devid);
  88
  89         if (status != EFI_SUCCESS) {
  90                 efi_err("Failed to read rom->devid\n");
  91                 goto free_struct;
  92         }
  93
  94         status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
  95                                 &rom->device, &rom->function);
  96
  97         if (status != EFI_SUCCESS)
  98                 goto free_struct;
  99
 100         memcpy(rom->romdata, romimage, romsize);
 101         return status;
 102
 103 free_struct:
 104         efi_bs_call(free_pool, rom);
 105         return status;
 106 }
 107
 108 /*
 109  * There's no way to return an informative status from this function,
 110  * because any analysis (and printing of error messages) needs to be
 111  * done directly at the EFI function call-site.
 112  *
 113  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 114  * just didn't find any PCI devices, but there's no way to tell outside
 115  * the context of the call.
 116  */
 117 static void setup_efi_pci(struct boot_params *params)
 118 {
 119         efi_status_t status;
 120         void **pci_handle = NULL;
 121         efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 122         unsigned long size = 0;
 123         struct setup_data *data;
 124         efi_handle_t h;
 125         int i;
 126
 127         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 128                              &pci_proto, NULL, &size, pci_handle);
 129
 130         if (status == EFI_BUFFER_TOO_SMALL) {
 131                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 132                                      (void **)&pci_handle);
 133
 134                 if (status != EFI_SUCCESS) {
 135                         efi_err("Failed to allocate memory for 'pci_handle'\n");
 136                         return;
 137                 }
 138
 139                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 140                                      &pci_proto, NULL, &size, pci_handle);
 141         }
 142
 143         if (status != EFI_SUCCESS)
 144                 goto free_handle;
 145
 146         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 147
 148         while (data && data->next)
 149                 data = (struct setup_data *)(unsigned long)data->next;
 150
 151         for_each_efi_handle(h, pci_handle, size, i) {
 152                 efi_pci_io_protocol_t *pci = NULL;
 153                 struct pci_setup_rom *rom;
 154
 155                 status = efi_bs_call(handle_protocol, h, &pci_proto,
 156                                      (void **)&pci);
 157                 if (status != EFI_SUCCESS || !pci)
 158                         continue;
 159
 160                 status = preserve_pci_rom_image(pci, &rom);
 161                 if (status != EFI_SUCCESS)
 162                         continue;
 163
 164                 if (data)
 165                         data->next = (unsigned long)rom;
 166                 else
 167                         params->hdr.setup_data = (unsigned long)rom;
 168
 169                 data = (struct setup_data *)rom;
 170         }
 171
 172 free_handle:
 173         efi_bs_call(free_pool, pci_handle);
 174 }
 175
 176 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 177 {
 178         efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 179         struct setup_data *data, *new;
 180         efi_status_t status;
 181         u32 size = 0;
 182         apple_properties_protocol_t *p;
 183
 184         status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 185         if (status != EFI_SUCCESS)
 186                 return;
 187
 188         if (efi_table_attr(p, version) != 0x10000) {
 189                 efi_err("Unsupported properties proto version\n");
 190                 return;
 191         }
 192
 193         efi_call_proto(p, get_all, NULL, &size);
 194         if (!size)
 195                 return;
 196
 197         do {
 198                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 199                                      size + sizeof(struct setup_data),
 200                                      (void **)&new);
 201                 if (status != EFI_SUCCESS) {
 202                         efi_err("Failed to allocate memory for 'properties'\n");
 203                         return;
 204                 }
 205
 206                 status = efi_call_proto(p, get_all, new->data, &size);
 207
 208                 if (status == EFI_BUFFER_TOO_SMALL)
 209                         efi_bs_call(free_pool, new);
 210         } while (status == EFI_BUFFER_TOO_SMALL);
 211
 212         new->type = SETUP_APPLE_PROPERTIES;
 213         new->len  = size;
 214         new->next = 0;
 215
 216         data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 217         if (!data) {
 218                 boot_params->hdr.setup_data = (unsigned long)new;
 219         } else {
 220                 while (data->next)
 221                         data = (struct setup_data *)(unsigned long)data->next;
 222                 data->next = (unsigned long)new;
 223         }
 224 }
 225
 226 efi_status_t efi_adjust_memory_range_protection(unsigned long start,
 227                                                 unsigned long size)
 228 {
 229         efi_status_t status;
 230         efi_gcd_memory_space_desc_t desc;
 231         unsigned long end, next;
 232         unsigned long rounded_start, rounded_end;
 233         unsigned long unprotect_start, unprotect_size;
 234
 235         rounded_start = rounddown(start, EFI_PAGE_SIZE);
 236         rounded_end = roundup(start + size, EFI_PAGE_SIZE);
 237
 238         if (memattr != NULL) {
 239                 status = efi_call_proto(memattr, clear_memory_attributes,
 240                                         rounded_start,
 241                                         rounded_end - rounded_start,
 242                                         EFI_MEMORY_XP);
 243                 if (status != EFI_SUCCESS)
 244                         efi_warn("Failed to clear EFI_MEMORY_XP attribute\n");
 245                 return status;
 246         }
 247
 248         if (efi_dxe_table == NULL)
 249                 return EFI_SUCCESS;
 250
 251         /*
 252          * Don't modify memory region attributes, they are
 253          * already suitable, to lower the possibility to
 254          * encounter firmware bugs.
 255          */
 256
 257         for (end = start + size; start < end; start = next) {
 258
 259                 status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
 260
 261                 if (status != EFI_SUCCESS)
 262                         break;
 263
 264                 next = desc.base_address + desc.length;
 265
 266                 /*
 267                  * Only system memory is suitable for trampoline/kernel image placement,
 268                  * so only this type of memory needs its attributes to be modified.
 269                  */
 270
 271                 if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
 272                     (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
 273                         continue;
 274
 275                 unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
 276                 unprotect_size = min(rounded_end, next) - unprotect_start;
 277
 278                 status = efi_dxe_call(set_memory_space_attributes,
 279                                       unprotect_start, unprotect_size,
 280                                       EFI_MEMORY_WB);
 281
 282                 if (status != EFI_SUCCESS) {
 283                         efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
 284                                  unprotect_start,
 285                                  unprotect_start + unprotect_size,
 286                                  status);
 287                         break;
 288                 }
 289         }
 290         return EFI_SUCCESS;
 291 }
 292
 293 static void setup_unaccepted_memory(void)
 294 {
 295         efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
 296         sev_memory_acceptance_protocol_t *proto;
 297         efi_status_t status;
 298
 299         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 300                 return;
 301
 302         /*
 303          * Enable unaccepted memory before calling exit boot services in order
 304          * for the UEFI to not accept all memory on EBS.
 305          */
 306         status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
 307                              (void **)&proto);
 308         if (status != EFI_SUCCESS)
 309                 return;
 310
 311         status = efi_call_proto(proto, allow_unaccepted_memory);
 312         if (status != EFI_SUCCESS)
 313                 efi_err("Memory acceptance protocol failed\n");
 314 }
 315
 316 static efi_char16_t *efistub_fw_vendor(void)
 317 {
 318         unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
 319
 320         return (efi_char16_t *)vendor;
 321 }
 322
 323 static const efi_char16_t apple[] = L"Apple";
 324
 325 static void setup_quirks(struct boot_params *boot_params)
 326 {
 327         if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
 328             !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
 329                 retrieve_apple_device_properties(boot_params);
 330 }
 331
 332 /*
 333  * See if we have Universal Graphics Adapter (UGA) protocol
 334  */
 335 static efi_status_t
 336 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 337 {
 338         efi_status_t status;
 339         u32 width, height;
 340         void **uga_handle = NULL;
 341         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 342         efi_handle_t handle;
 343         int i;
 344
 345         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 346                              (void **)&uga_handle);
 347         if (status != EFI_SUCCESS)
 348                 return status;
 349
 350         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 351                              uga_proto, NULL, &size, uga_handle);
 352         if (status != EFI_SUCCESS)
 353                 goto free_handle;
 354
 355         height = 0;
 356         width = 0;
 357
 358         first_uga = NULL;
 359         for_each_efi_handle(handle, uga_handle, size, i) {
 360                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 361                 u32 w, h, depth, refresh;
 362                 void *pciio;
 363
 364                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 365                                      (void **)&uga);
 366                 if (status != EFI_SUCCESS)
 367                         continue;
 368
 369                 pciio = NULL;
 370                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 371
 372                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 373                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 374                         width = w;
 375                         height = h;
 376
 377                         /*
 378                          * Once we've found a UGA supporting PCIIO,
 379                          * don't bother looking any further.
 380                          */
 381                         if (pciio)
 382                                 break;
 383
 384                         first_uga = uga;
 385                 }
 386         }
 387
 388         if (!width && !height)
 389                 goto free_handle;
 390
 391         /* EFI framebuffer */
 392         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 393
 394         si->lfb_depth           = 32;
 395         si->lfb_width           = width;
 396         si->lfb_height          = height;
 397
 398         si->red_size            = 8;
 399         si->red_pos             = 16;
 400         si->green_size          = 8;
 401         si->green_pos           = 8;
 402         si->blue_size           = 8;
 403         si->blue_pos            = 0;
 404         si->rsvd_size           = 8;
 405         si->rsvd_pos            = 24;
 406
 407 free_handle:
 408         efi_bs_call(free_pool, uga_handle);
 409
 410         return status;
 411 }
 412
 413 static void setup_graphics(struct boot_params *boot_params)
 414 {
 415         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 416         struct screen_info *si;
 417         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 418         efi_status_t status;
 419         unsigned long size;
 420         void **gop_handle = NULL;
 421         void **uga_handle = NULL;
 422
 423         si = &boot_params->screen_info;
 424         memset(si, 0, sizeof(*si));
 425
 426         size = 0;
 427         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 428                              &graphics_proto, NULL, &size, gop_handle);
 429         if (status == EFI_BUFFER_TOO_SMALL)
 430                 status = efi_setup_gop(si, &graphics_proto, size);
 431
 432         if (status != EFI_SUCCESS) {
 433                 size = 0;
 434                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 435                                      &uga_proto, NULL, &size, uga_handle);
 436                 if (status == EFI_BUFFER_TOO_SMALL)
 437                         setup_uga(si, &uga_proto, size);
 438         }
 439 }
 440
 441
 442 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 443 {
 444         efi_bs_call(exit, handle, status, 0, NULL);
 445         for(;;)
 446                 asm("hlt");
 447 }
 448
 449 void __noreturn efi_stub_entry(efi_handle_t handle,
 450                                efi_system_table_t *sys_table_arg,
 451                                struct boot_params *boot_params);
 452
 453 /*
 454  * Because the x86 boot code expects to be passed a boot_params we
 455  * need to create one ourselves (usually the bootloader would create
 456  * one for us).
 457  */
 458 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 459                                    efi_system_table_t *sys_table_arg)
 460 {
 461         struct boot_params *boot_params;
 462         struct setup_header *hdr;
 463         void *image_base;
 464         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 465         int options_size = 0;
 466         efi_status_t status;
 467         char *cmdline_ptr;
 468
 469         efi_system_table = sys_table_arg;
 470
 471         /* Check if we were booted by the EFI firmware */
 472         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 473                 efi_exit(handle, EFI_INVALID_PARAMETER);
 474
 475         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 476         if (status != EFI_SUCCESS) {
 477                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 478                 efi_exit(handle, status);
 479         }
 480
 481         image_base = efi_table_attr(image, image_base);
 482
 483         status = efi_allocate_pages(sizeof(struct boot_params),
 484                                     (unsigned long *)&boot_params, ULONG_MAX);
 485         if (status != EFI_SUCCESS) {
 486                 efi_err("Failed to allocate lowmem for boot params\n");
 487                 efi_exit(handle, status);
 488         }
 489
 490         memset(boot_params, 0x0, sizeof(struct boot_params));
 491
 492         hdr = &boot_params->hdr;
 493
 494         /* Copy the setup header from the second sector to boot_params */
 495         memcpy(&hdr->jump, image_base + 512,
 496                sizeof(struct setup_header) - offsetof(struct setup_header, jump));
 497
 498         /*
 499          * Fill out some of the header fields ourselves because the
 500          * EFI firmware loader doesn't load the first sector.
 501          */
 502         hdr->root_flags = 1;
 503         hdr->vid_mode   = 0xffff;
 504         hdr->boot_flag  = 0xAA55;
 505
 506         hdr->type_of_loader = 0x21;
 507
 508         /* Convert unicode cmdline to ascii */
 509         cmdline_ptr = efi_convert_cmdline(image, &options_size);
 510         if (!cmdline_ptr)
 511                 goto fail;
 512
 513         efi_set_u64_split((unsigned long)cmdline_ptr,
 514                           &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);
 515
 516         hdr->ramdisk_image = 0;
 517         hdr->ramdisk_size = 0;
 518
 519         /*
 520          * Disregard any setup data that was provided by the bootloader:
 521          * setup_data could be pointing anywhere, and we have no way of
 522          * authenticating or validating the payload.
 523          */
 524         hdr->setup_data = 0;
 525
 526         efi_stub_entry(handle, sys_table_arg, boot_params);
 527         /* not reached */
 528
 529 fail:
 530         efi_free(sizeof(struct boot_params), (unsigned long)boot_params);
 531
 532         efi_exit(handle, status);
 533 }
 534
 535 static void add_e820ext(struct boot_params *params,
 536                         struct setup_data *e820ext, u32 nr_entries)
 537 {
 538         struct setup_data *data;
 539
 540         e820ext->type = SETUP_E820_EXT;
 541         e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 542         e820ext->next = 0;
 543
 544         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 545
 546         while (data && data->next)
 547                 data = (struct setup_data *)(unsigned long)data->next;
 548
 549         if (data)
 550                 data->next = (unsigned long)e820ext;
 551         else
 552                 params->hdr.setup_data = (unsigned long)e820ext;
 553 }
 554
 555 static efi_status_t
 556 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 557 {
 558         struct boot_e820_entry *entry = params->e820_table;
 559         struct efi_info *efi = &params->efi_info;
 560         struct boot_e820_entry *prev = NULL;
 561         u32 nr_entries;
 562         u32 nr_desc;
 563         int i;
 564
 565         nr_entries = 0;
 566         nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
 567
 568         for (i = 0; i < nr_desc; i++) {
 569                 efi_memory_desc_t *d;
 570                 unsigned int e820_type = 0;
 571                 unsigned long m = efi->efi_memmap;
 572
 573 #ifdef CONFIG_X86_64
 574                 m |= (u64)efi->efi_memmap_hi << 32;
 575 #endif
 576
 577                 d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 578                 switch (d->type) {
 579                 case EFI_RESERVED_TYPE:
 580                 case EFI_RUNTIME_SERVICES_CODE:
 581                 case EFI_RUNTIME_SERVICES_DATA:
 582                 case EFI_MEMORY_MAPPED_IO:
 583                 case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 584                 case EFI_PAL_CODE:
 585                         e820_type = E820_TYPE_RESERVED;
 586                         break;
 587
 588                 case EFI_UNUSABLE_MEMORY:
 589                         e820_type = E820_TYPE_UNUSABLE;
 590                         break;
 591
 592                 case EFI_ACPI_RECLAIM_MEMORY:
 593                         e820_type = E820_TYPE_ACPI;
 594                         break;
 595
 596                 case EFI_LOADER_CODE:
 597                 case EFI_LOADER_DATA:
 598                 case EFI_BOOT_SERVICES_CODE:
 599                 case EFI_BOOT_SERVICES_DATA:
 600                 case EFI_CONVENTIONAL_MEMORY:
 601                         if (efi_soft_reserve_enabled() &&
 602                             (d->attribute & EFI_MEMORY_SP))
 603                                 e820_type = E820_TYPE_SOFT_RESERVED;
 604                         else
 605                                 e820_type = E820_TYPE_RAM;
 606                         break;
 607
 608                 case EFI_ACPI_MEMORY_NVS:
 609                         e820_type = E820_TYPE_NVS;
 610                         break;
 611
 612                 case EFI_PERSISTENT_MEMORY:
 613                         e820_type = E820_TYPE_PMEM;
 614                         break;
 615
 616                 case EFI_UNACCEPTED_MEMORY:
 617                         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 618                                 continue;
 619                         e820_type = E820_TYPE_RAM;
 620                         process_unaccepted_memory(d->phys_addr,
 621                                                   d->phys_addr + PAGE_SIZE * d->num_pages);
 622                         break;
 623                 default:
 624                         continue;
 625                 }
 626
 627                 /* Merge adjacent mappings */
 628                 if (prev && prev->type == e820_type &&
 629                     (prev->addr + prev->size) == d->phys_addr) {
 630                         prev->size += d->num_pages << 12;
 631                         continue;
 632                 }
 633
 634                 if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 635                         u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 636                                    sizeof(struct setup_data);
 637
 638                         if (!e820ext || e820ext_size < need)
 639                                 return EFI_BUFFER_TOO_SMALL;
 640
 641                         /* boot_params map full, switch to e820 extended */
 642                         entry = (struct boot_e820_entry *)e820ext->data;
 643                 }
 644
 645                 entry->addr = d->phys_addr;
 646                 entry->size = d->num_pages << PAGE_SHIFT;
 647                 entry->type = e820_type;
 648                 prev = entry++;
 649                 nr_entries++;
 650         }
 651
 652         if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 653                 u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
 654
 655                 add_e820ext(params, e820ext, nr_e820ext);
 656                 nr_entries -= nr_e820ext;
 657         }
 658
 659         params->e820_entries = (u8)nr_entries;
 660
 661         return EFI_SUCCESS;
 662 }
 663
 664 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 665                                   u32 *e820ext_size)
 666 {
 667         efi_status_t status;
 668         unsigned long size;
 669
 670         size = sizeof(struct setup_data) +
 671                 sizeof(struct e820_entry) * nr_desc;
 672
 673         if (*e820ext) {
 674                 efi_bs_call(free_pool, *e820ext);
 675                 *e820ext = NULL;
 676                 *e820ext_size = 0;
 677         }
 678
 679         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 680                              (void **)e820ext);
 681         if (status == EFI_SUCCESS)
 682                 *e820ext_size = size;
 683
 684         return status;
 685 }
 686
 687 static efi_status_t allocate_e820(struct boot_params *params,
 688                                   struct setup_data **e820ext,
 689                                   u32 *e820ext_size)
 690 {
 691         struct efi_boot_memmap *map;
 692         efi_status_t status;
 693         __u32 nr_desc;
 694
 695         status = efi_get_memory_map(&map, false);
 696         if (status != EFI_SUCCESS)
 697                 return status;
 698
 699         nr_desc = map->map_size / map->desc_size;
 700         if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
 701                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
 702                                  EFI_MMAP_NR_SLACK_SLOTS;
 703
 704                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 705         }
 706
 707         if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
 708                 status = allocate_unaccepted_bitmap(nr_desc, map);
 709
 710         efi_bs_call(free_pool, map);
 711         return status;
 712 }
 713
 714 struct exit_boot_struct {
 715         struct boot_params      *boot_params;
 716         struct efi_info         *efi;
 717 };
 718
 719 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 720                                    void *priv)
 721 {
 722         const char *signature;
 723         struct exit_boot_struct *p = priv;
 724
 725         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 726                                    : EFI32_LOADER_SIGNATURE;
 727         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 728
 729         efi_set_u64_split((unsigned long)efi_system_table,
 730                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 731         p->efi->efi_memdesc_size        = map->desc_size;
 732         p->efi->efi_memdesc_version     = map->desc_ver;
 733         efi_set_u64_split((unsigned long)map->map,
 734                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 735         p->efi->efi_memmap_size         = map->map_size;
 736
 737         return EFI_SUCCESS;
 738 }
 739
 740 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 741 {
 742         struct setup_data *e820ext = NULL;
 743         __u32 e820ext_size = 0;
 744         efi_status_t status;
 745         struct exit_boot_struct priv;
 746
 747         priv.boot_params        = boot_params;
 748         priv.efi                = &boot_params->efi_info;
 749
 750         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 751         if (status != EFI_SUCCESS)
 752                 return status;
 753
 754         /* Might as well exit boot services now */
 755         status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 756         if (status != EFI_SUCCESS)
 757                 return status;
 758
 759         /* Historic? */
 760         boot_params->alt_mem_k  = 32 * 1024;
 761
 762         status = setup_e820(boot_params, e820ext, e820ext_size);
 763         if (status != EFI_SUCCESS)
 764                 return status;
 765
 766         return EFI_SUCCESS;
 767 }
 768
 769 static bool have_unsupported_snp_features(void)
 770 {
 771         u64 unsupported;
 772
 773         unsupported = snp_get_unsupported_features(sev_get_status());
 774         if (unsupported) {
 775                 efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
 776                         unsupported);
 777                 return true;
 778         }
 779         return false;
 780 }
 781
 782 static void efi_get_seed(void *seed, int size)
 783 {
 784         efi_get_random_bytes(size, seed);
 785
 786         /*
 787          * This only updates seed[0] when running on 32-bit, but in that case,
 788          * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
 789          */
 790         *(unsigned long *)seed ^= kaslr_get_random_long("EFI");
 791 }
 792
 793 static void error(char *str)
 794 {
 795         efi_warn("Decompression failed: %s\n", str);
 796 }
 797
 798 static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
 799 {
 800         unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
 801         unsigned long addr, alloc_size, entry;
 802         efi_status_t status;
 803         u32 seed[2] = {};
 804
 805         /* determine the required size of the allocation */
 806         alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
 807                            MIN_KERNEL_ALIGN);
 808
 809         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
 810                 u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
 811                 static const efi_char16_t ami[] = L"American Megatrends";
 812
 813                 efi_get_seed(seed, sizeof(seed));
 814
 815                 virt_addr += (range * seed[1]) >> 32;
 816                 virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
 817
 818                 /*
 819                  * Older Dell systems with AMI UEFI firmware v2.0 may hang
 820                  * while decompressing the kernel if physical address
 821                  * randomization is enabled.
 822                  *
 823                  * https://bugzilla.kernel.org/show_bug.cgi?id=218173
 824                  */
 825                 if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
 826                     !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
 827                         efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
 828                         seed[0] = 0;
 829                 }
 830         }
 831
 832         status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
 833                                   seed[0], EFI_LOADER_CODE,
 834                                   EFI_X86_KERNEL_ALLOC_LIMIT);
 835         if (status != EFI_SUCCESS)
 836                 return status;
 837
 838         entry = decompress_kernel((void *)addr, virt_addr, error);
 839         if (entry == ULONG_MAX) {
 840                 efi_free(alloc_size, addr);
 841                 return EFI_LOAD_ERROR;
 842         }
 843
 844         *kernel_entry = addr + entry;
 845
 846         return efi_adjust_memory_range_protection(addr, kernel_total_size);
 847 }
 848
 849 static void __noreturn enter_kernel(unsigned long kernel_addr,
 850                                     struct boot_params *boot_params)
 851 {
 852         /* enter decompressed kernel with boot_params pointer in RSI/ESI */
 853         asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
 854
 855         unreachable();
 856 }
 857
 858 /*
 859  * On success, this routine will jump to the relocated image directly and never
 860  * return.  On failure, it will exit to the firmware via efi_exit() instead of
 861  * returning.
 862  */
 863 void __noreturn efi_stub_entry(efi_handle_t handle,
 864                                efi_system_table_t *sys_table_arg,
 865                                struct boot_params *boot_params)
 866 {
 867         efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
 868         struct setup_header *hdr = &boot_params->hdr;
 869         const struct linux_efi_initrd *initrd = NULL;
 870         unsigned long kernel_entry;
 871         efi_status_t status;
 872
 873         boot_params_pointer = boot_params;
 874
 875         efi_system_table = sys_table_arg;
 876         /* Check if we were booted by the EFI firmware */
 877         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 878                 efi_exit(handle, EFI_INVALID_PARAMETER);
 879
 880         if (have_unsupported_snp_features())
 881                 efi_exit(handle, EFI_UNSUPPORTED);
 882
 883         if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
 884                 efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
 885                 if (efi_dxe_table &&
 886                     efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
 887                         efi_warn("Ignoring DXE services table: invalid signature\n");
 888                         efi_dxe_table = NULL;
 889                 }
 890         }
 891
 892         /* grab the memory attributes protocol if it exists */
 893         efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
 894
 895         status = efi_setup_5level_paging();
 896         if (status != EFI_SUCCESS) {
 897                 efi_err("efi_setup_5level_paging() failed!\n");
 898                 goto fail;
 899         }
 900
 901 #ifdef CONFIG_CMDLINE_BOOL
 902         status = efi_parse_options(CONFIG_CMDLINE);
 903         if (status != EFI_SUCCESS) {
 904                 efi_err("Failed to parse options\n");
 905                 goto fail;
 906         }
 907 #endif
 908         if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 909                 unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 910                                                ((u64)boot_params->ext_cmd_line_ptr << 32));
 911                 status = efi_parse_options((char *)cmdline_paddr);
 912                 if (status != EFI_SUCCESS) {
 913                         efi_err("Failed to parse options\n");
 914                         goto fail;
 915                 }
 916         }
 917
 918         status = efi_decompress_kernel(&kernel_entry);
 919         if (status != EFI_SUCCESS) {
 920                 efi_err("Failed to decompress kernel\n");
 921                 goto fail;
 922         }
 923
 924         /*
 925          * At this point, an initrd may already have been loaded by the
 926          * bootloader and passed via bootparams. We permit an initrd loaded
 927          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 928          *
 929          * If the device path is not present, any command-line initrd=
 930          * arguments will be processed only if image is not NULL, which will be
 931          * the case only if we were loaded via the PE entry point.
 932          */
 933         status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
 934                                  &initrd);
 935         if (status != EFI_SUCCESS)
 936                 goto fail;
 937         if (initrd && initrd->size > 0) {
 938                 efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
 939                                   &boot_params->ext_ramdisk_image);
 940                 efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
 941                                   &boot_params->ext_ramdisk_size);
 942         }
 943
 944
 945         /*
 946          * If the boot loader gave us a value for secure_boot then we use that,
 947          * otherwise we ask the BIOS.
 948          */
 949         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 950                 boot_params->secure_boot = efi_get_secureboot();
 951
 952         /* Ask the firmware to clear memory on unclean shutdown */
 953         efi_enable_reset_attack_mitigation();
 954
 955         efi_random_get_seed();
 956
 957         efi_retrieve_tpm2_eventlog();
 958
 959         setup_graphics(boot_params);
 960
 961         setup_efi_pci(boot_params);
 962
 963         setup_quirks(boot_params);
 964
 965         setup_unaccepted_memory();
 966
 967         status = exit_boot(boot_params, handle);
 968         if (status != EFI_SUCCESS) {
 969                 efi_err("exit_boot() failed!\n");
 970                 goto fail;
 971         }
 972
 973         /*
 974          * Call the SEV init code while still running with the firmware's
 975          * GDT/IDT, so #VC exceptions will be handled by EFI.
 976          */
 977         sev_enable(boot_params);
 978
 979         efi_5level_switch();
 980
 981         enter_kernel(kernel_entry, boot_params);
 982 fail:
 983         efi_err("efi_stub_entry() failed!\n");
 984
 985         efi_exit(handle, status);
 986 }
 987
 988 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
 989 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 990                         struct boot_params *boot_params)
 991 {
 992         extern char _bss[], _ebss[];
 993
 994         memset(_bss, 0, _ebss - _bss);
 995         efi_stub_entry(handle, sys_table_arg, boot_params);
 996 }
 997
 998 #ifndef CONFIG_EFI_MIXED
 999 extern __alias(efi_handover_entry)
1000 void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
1001                       struct boot_params *boot_params);
1002
1003 extern __alias(efi_handover_entry)
1004 void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
1005                       struct boot_params *boot_params);
1006 #endif
1007 #endif