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, set_memory_attributes,
 240                                         rounded_start,
 241                                         rounded_end - rounded_start,
 242                                         EFI_MEMORY_RO);
 243                 if (status != EFI_SUCCESS) {
 244                         efi_warn("Failed to set EFI_MEMORY_RO attribute\n");
 245                         return status;
 246                 }
 247
 248                 status = efi_call_proto(memattr, clear_memory_attributes,
 249                                         rounded_start,
 250                                         rounded_end - rounded_start,
 251                                         EFI_MEMORY_XP);
 252                 if (status != EFI_SUCCESS)
 253                         efi_warn("Failed to clear EFI_MEMORY_XP attribute\n");
 254                 return status;
 255         }
 256
 257         if (efi_dxe_table == NULL)
 258                 return EFI_SUCCESS;
 259
 260         /*
 261          * Don't modify memory region attributes, they are
 262          * already suitable, to lower the possibility to
 263          * encounter firmware bugs.
 264          */
 265
 266         for (end = start + size; start < end; start = next) {
 267
 268                 status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
 269
 270                 if (status != EFI_SUCCESS)
 271                         break;
 272
 273                 next = desc.base_address + desc.length;
 274
 275                 /*
 276                  * Only system memory is suitable for trampoline/kernel image placement,
 277                  * so only this type of memory needs its attributes to be modified.
 278                  */
 279
 280                 if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
 281                     (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
 282                         continue;
 283
 284                 unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
 285                 unprotect_size = min(rounded_end, next) - unprotect_start;
 286
 287                 status = efi_dxe_call(set_memory_space_attributes,
 288                                       unprotect_start, unprotect_size,
 289                                       EFI_MEMORY_WB);
 290
 291                 if (status != EFI_SUCCESS) {
 292                         efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
 293                                  unprotect_start,
 294                                  unprotect_start + unprotect_size,
 295                                  status);
 296                         break;
 297                 }
 298         }
 299         return EFI_SUCCESS;
 300 }
 301
 302 static void setup_unaccepted_memory(void)
 303 {
 304         efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
 305         sev_memory_acceptance_protocol_t *proto;
 306         efi_status_t status;
 307
 308         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 309                 return;
 310
 311         /*
 312          * Enable unaccepted memory before calling exit boot services in order
 313          * for the UEFI to not accept all memory on EBS.
 314          */
 315         status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
 316                              (void **)&proto);
 317         if (status != EFI_SUCCESS)
 318                 return;
 319
 320         status = efi_call_proto(proto, allow_unaccepted_memory);
 321         if (status != EFI_SUCCESS)
 322                 efi_err("Memory acceptance protocol failed\n");
 323 }
 324
 325 static efi_char16_t *efistub_fw_vendor(void)
 326 {
 327         unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
 328
 329         return (efi_char16_t *)vendor;
 330 }
 331
 332 static const efi_char16_t apple[] = L"Apple";
 333
 334 static void setup_quirks(struct boot_params *boot_params)
 335 {
 336         if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
 337             !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
 338                 retrieve_apple_device_properties(boot_params);
 339 }
 340
 341 /*
 342  * See if we have Universal Graphics Adapter (UGA) protocol
 343  */
 344 static efi_status_t
 345 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 346 {
 347         efi_status_t status;
 348         u32 width, height;
 349         void **uga_handle = NULL;
 350         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 351         efi_handle_t handle;
 352         int i;
 353
 354         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 355                              (void **)&uga_handle);
 356         if (status != EFI_SUCCESS)
 357                 return status;
 358
 359         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 360                              uga_proto, NULL, &size, uga_handle);
 361         if (status != EFI_SUCCESS)
 362                 goto free_handle;
 363
 364         height = 0;
 365         width = 0;
 366
 367         first_uga = NULL;
 368         for_each_efi_handle(handle, uga_handle, size, i) {
 369                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 370                 u32 w, h, depth, refresh;
 371                 void *pciio;
 372
 373                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 374                                      (void **)&uga);
 375                 if (status != EFI_SUCCESS)
 376                         continue;
 377
 378                 pciio = NULL;
 379                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 380
 381                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 382                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 383                         width = w;
 384                         height = h;
 385
 386                         /*
 387                          * Once we've found a UGA supporting PCIIO,
 388                          * don't bother looking any further.
 389                          */
 390                         if (pciio)
 391                                 break;
 392
 393                         first_uga = uga;
 394                 }
 395         }
 396
 397         if (!width && !height)
 398                 goto free_handle;
 399
 400         /* EFI framebuffer */
 401         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 402
 403         si->lfb_depth           = 32;
 404         si->lfb_width           = width;
 405         si->lfb_height          = height;
 406
 407         si->red_size            = 8;
 408         si->red_pos             = 16;
 409         si->green_size          = 8;
 410         si->green_pos           = 8;
 411         si->blue_size           = 8;
 412         si->blue_pos            = 0;
 413         si->rsvd_size           = 8;
 414         si->rsvd_pos            = 24;
 415
 416 free_handle:
 417         efi_bs_call(free_pool, uga_handle);
 418
 419         return status;
 420 }
 421
 422 static void setup_graphics(struct boot_params *boot_params)
 423 {
 424         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 425         struct screen_info *si;
 426         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 427         efi_status_t status;
 428         unsigned long size;
 429         void **gop_handle = NULL;
 430         void **uga_handle = NULL;
 431
 432         si = &boot_params->screen_info;
 433         memset(si, 0, sizeof(*si));
 434
 435         size = 0;
 436         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 437                              &graphics_proto, NULL, &size, gop_handle);
 438         if (status == EFI_BUFFER_TOO_SMALL)
 439                 status = efi_setup_gop(si, &graphics_proto, size);
 440
 441         if (status != EFI_SUCCESS) {
 442                 size = 0;
 443                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 444                                      &uga_proto, NULL, &size, uga_handle);
 445                 if (status == EFI_BUFFER_TOO_SMALL)
 446                         setup_uga(si, &uga_proto, size);
 447         }
 448 }
 449
 450
 451 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 452 {
 453         efi_bs_call(exit, handle, status, 0, NULL);
 454         for(;;)
 455                 asm("hlt");
 456 }
 457
 458 void __noreturn efi_stub_entry(efi_handle_t handle,
 459                                efi_system_table_t *sys_table_arg,
 460                                struct boot_params *boot_params);
 461
 462 /*
 463  * Because the x86 boot code expects to be passed a boot_params we
 464  * need to create one ourselves (usually the bootloader would create
 465  * one for us).
 466  */
 467 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 468                                    efi_system_table_t *sys_table_arg)
 469 {
 470         static struct boot_params boot_params __page_aligned_bss;
 471         struct setup_header *hdr = &boot_params.hdr;
 472         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 473         int options_size = 0;
 474         efi_status_t status;
 475         char *cmdline_ptr;
 476
 477         efi_system_table = sys_table_arg;
 478
 479         /* Check if we were booted by the EFI firmware */
 480         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 481                 efi_exit(handle, EFI_INVALID_PARAMETER);
 482
 483         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 484         if (status != EFI_SUCCESS) {
 485                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 486                 efi_exit(handle, status);
 487         }
 488
 489         /* Assign the setup_header fields that the kernel actually cares about */
 490         hdr->root_flags = 1;
 491         hdr->vid_mode   = 0xffff;
 492
 493         hdr->type_of_loader = 0x21;
 494
 495         /* Convert unicode cmdline to ascii */
 496         cmdline_ptr = efi_convert_cmdline(image, &options_size);
 497         if (!cmdline_ptr)
 498                 goto fail;
 499
 500         efi_set_u64_split((unsigned long)cmdline_ptr, &hdr->cmd_line_ptr,
 501                           &boot_params.ext_cmd_line_ptr);
 502
 503         efi_stub_entry(handle, sys_table_arg, &boot_params);
 504         /* not reached */
 505
 506 fail:
 507         efi_exit(handle, status);
 508 }
 509
 510 static void add_e820ext(struct boot_params *params,
 511                         struct setup_data *e820ext, u32 nr_entries)
 512 {
 513         struct setup_data *data;
 514
 515         e820ext->type = SETUP_E820_EXT;
 516         e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 517         e820ext->next = 0;
 518
 519         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 520
 521         while (data && data->next)
 522                 data = (struct setup_data *)(unsigned long)data->next;
 523
 524         if (data)
 525                 data->next = (unsigned long)e820ext;
 526         else
 527                 params->hdr.setup_data = (unsigned long)e820ext;
 528 }
 529
 530 static efi_status_t
 531 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 532 {
 533         struct boot_e820_entry *entry = params->e820_table;
 534         struct efi_info *efi = &params->efi_info;
 535         struct boot_e820_entry *prev = NULL;
 536         u32 nr_entries;
 537         u32 nr_desc;
 538         int i;
 539
 540         nr_entries = 0;
 541         nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
 542
 543         for (i = 0; i < nr_desc; i++) {
 544                 efi_memory_desc_t *d;
 545                 unsigned int e820_type = 0;
 546                 unsigned long m = efi->efi_memmap;
 547
 548 #ifdef CONFIG_X86_64
 549                 m |= (u64)efi->efi_memmap_hi << 32;
 550 #endif
 551
 552                 d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 553                 switch (d->type) {
 554                 case EFI_RESERVED_TYPE:
 555                 case EFI_RUNTIME_SERVICES_CODE:
 556                 case EFI_RUNTIME_SERVICES_DATA:
 557                 case EFI_MEMORY_MAPPED_IO:
 558                 case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 559                 case EFI_PAL_CODE:
 560                         e820_type = E820_TYPE_RESERVED;
 561                         break;
 562
 563                 case EFI_UNUSABLE_MEMORY:
 564                         e820_type = E820_TYPE_UNUSABLE;
 565                         break;
 566
 567                 case EFI_ACPI_RECLAIM_MEMORY:
 568                         e820_type = E820_TYPE_ACPI;
 569                         break;
 570
 571                 case EFI_LOADER_CODE:
 572                 case EFI_LOADER_DATA:
 573                 case EFI_BOOT_SERVICES_CODE:
 574                 case EFI_BOOT_SERVICES_DATA:
 575                 case EFI_CONVENTIONAL_MEMORY:
 576                         if (efi_soft_reserve_enabled() &&
 577                             (d->attribute & EFI_MEMORY_SP))
 578                                 e820_type = E820_TYPE_SOFT_RESERVED;
 579                         else
 580                                 e820_type = E820_TYPE_RAM;
 581                         break;
 582
 583                 case EFI_ACPI_MEMORY_NVS:
 584                         e820_type = E820_TYPE_NVS;
 585                         break;
 586
 587                 case EFI_PERSISTENT_MEMORY:
 588                         e820_type = E820_TYPE_PMEM;
 589                         break;
 590
 591                 case EFI_UNACCEPTED_MEMORY:
 592                         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 593                                 continue;
 594                         e820_type = E820_TYPE_RAM;
 595                         process_unaccepted_memory(d->phys_addr,
 596                                                   d->phys_addr + PAGE_SIZE * d->num_pages);
 597                         break;
 598                 default:
 599                         continue;
 600                 }
 601
 602                 /* Merge adjacent mappings */
 603                 if (prev && prev->type == e820_type &&
 604                     (prev->addr + prev->size) == d->phys_addr) {
 605                         prev->size += d->num_pages << 12;
 606                         continue;
 607                 }
 608
 609                 if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 610                         u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 611                                    sizeof(struct setup_data);
 612
 613                         if (!e820ext || e820ext_size < need)
 614                                 return EFI_BUFFER_TOO_SMALL;
 615
 616                         /* boot_params map full, switch to e820 extended */
 617                         entry = (struct boot_e820_entry *)e820ext->data;
 618                 }
 619
 620                 entry->addr = d->phys_addr;
 621                 entry->size = d->num_pages << PAGE_SHIFT;
 622                 entry->type = e820_type;
 623                 prev = entry++;
 624                 nr_entries++;
 625         }
 626
 627         if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 628                 u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
 629
 630                 add_e820ext(params, e820ext, nr_e820ext);
 631                 nr_entries -= nr_e820ext;
 632         }
 633
 634         params->e820_entries = (u8)nr_entries;
 635
 636         return EFI_SUCCESS;
 637 }
 638
 639 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 640                                   u32 *e820ext_size)
 641 {
 642         efi_status_t status;
 643         unsigned long size;
 644
 645         size = sizeof(struct setup_data) +
 646                 sizeof(struct e820_entry) * nr_desc;
 647
 648         if (*e820ext) {
 649                 efi_bs_call(free_pool, *e820ext);
 650                 *e820ext = NULL;
 651                 *e820ext_size = 0;
 652         }
 653
 654         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 655                              (void **)e820ext);
 656         if (status == EFI_SUCCESS)
 657                 *e820ext_size = size;
 658
 659         return status;
 660 }
 661
 662 static efi_status_t allocate_e820(struct boot_params *params,
 663                                   struct setup_data **e820ext,
 664                                   u32 *e820ext_size)
 665 {
 666         struct efi_boot_memmap *map;
 667         efi_status_t status;
 668         __u32 nr_desc;
 669
 670         status = efi_get_memory_map(&map, false);
 671         if (status != EFI_SUCCESS)
 672                 return status;
 673
 674         nr_desc = map->map_size / map->desc_size;
 675         if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
 676                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
 677                                  EFI_MMAP_NR_SLACK_SLOTS;
 678
 679                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 680         }
 681
 682         if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
 683                 status = allocate_unaccepted_bitmap(nr_desc, map);
 684
 685         efi_bs_call(free_pool, map);
 686         return status;
 687 }
 688
 689 struct exit_boot_struct {
 690         struct boot_params      *boot_params;
 691         struct efi_info         *efi;
 692 };
 693
 694 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 695                                    void *priv)
 696 {
 697         const char *signature;
 698         struct exit_boot_struct *p = priv;
 699
 700         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 701                                    : EFI32_LOADER_SIGNATURE;
 702         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 703
 704         efi_set_u64_split((unsigned long)efi_system_table,
 705                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 706         p->efi->efi_memdesc_size        = map->desc_size;
 707         p->efi->efi_memdesc_version     = map->desc_ver;
 708         efi_set_u64_split((unsigned long)map->map,
 709                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 710         p->efi->efi_memmap_size         = map->map_size;
 711
 712         return EFI_SUCCESS;
 713 }
 714
 715 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 716 {
 717         struct setup_data *e820ext = NULL;
 718         __u32 e820ext_size = 0;
 719         efi_status_t status;
 720         struct exit_boot_struct priv;
 721
 722         priv.boot_params        = boot_params;
 723         priv.efi                = &boot_params->efi_info;
 724
 725         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 726         if (status != EFI_SUCCESS)
 727                 return status;
 728
 729         /* Might as well exit boot services now */
 730         status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 731         if (status != EFI_SUCCESS)
 732                 return status;
 733
 734         /* Historic? */
 735         boot_params->alt_mem_k  = 32 * 1024;
 736
 737         status = setup_e820(boot_params, e820ext, e820ext_size);
 738         if (status != EFI_SUCCESS)
 739                 return status;
 740
 741         return EFI_SUCCESS;
 742 }
 743
 744 static bool have_unsupported_snp_features(void)
 745 {
 746         u64 unsupported;
 747
 748         unsupported = snp_get_unsupported_features(sev_get_status());
 749         if (unsupported) {
 750                 efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
 751                         unsupported);
 752                 return true;
 753         }
 754         return false;
 755 }
 756
 757 static void efi_get_seed(void *seed, int size)
 758 {
 759         efi_get_random_bytes(size, seed);
 760
 761         /*
 762          * This only updates seed[0] when running on 32-bit, but in that case,
 763          * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
 764          */
 765         *(unsigned long *)seed ^= kaslr_get_random_long("EFI");
 766 }
 767
 768 static void error(char *str)
 769 {
 770         efi_warn("Decompression failed: %s\n", str);
 771 }
 772
 773 static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
 774 {
 775         unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
 776         unsigned long addr, alloc_size, entry;
 777         efi_status_t status;
 778         u32 seed[2] = {};
 779
 780         /* determine the required size of the allocation */
 781         alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
 782                            MIN_KERNEL_ALIGN);
 783
 784         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
 785                 u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
 786                 static const efi_char16_t ami[] = L"American Megatrends";
 787
 788                 efi_get_seed(seed, sizeof(seed));
 789
 790                 virt_addr += (range * seed[1]) >> 32;
 791                 virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
 792
 793                 /*
 794                  * Older Dell systems with AMI UEFI firmware v2.0 may hang
 795                  * while decompressing the kernel if physical address
 796                  * randomization is enabled.
 797                  *
 798                  * https://bugzilla.kernel.org/show_bug.cgi?id=218173
 799                  */
 800                 if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
 801                     !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
 802                         efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
 803                         seed[0] = 0;
 804                 }
 805
 806                 boot_params_ptr->hdr.loadflags |= KASLR_FLAG;
 807         }
 808
 809         status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
 810                                   seed[0], EFI_LOADER_CODE,
 811                                   LOAD_PHYSICAL_ADDR,
 812                                   EFI_X86_KERNEL_ALLOC_LIMIT);
 813         if (status != EFI_SUCCESS)
 814                 return status;
 815
 816         entry = decompress_kernel((void *)addr, virt_addr, error);
 817         if (entry == ULONG_MAX) {
 818                 efi_free(alloc_size, addr);
 819                 return EFI_LOAD_ERROR;
 820         }
 821
 822         *kernel_entry = addr + entry;
 823
 824         return efi_adjust_memory_range_protection(addr, kernel_text_size);
 825 }
 826
 827 static void __noreturn enter_kernel(unsigned long kernel_addr,
 828                                     struct boot_params *boot_params)
 829 {
 830         /* enter decompressed kernel with boot_params pointer in RSI/ESI */
 831         asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
 832
 833         unreachable();
 834 }
 835
 836 /*
 837  * On success, this routine will jump to the relocated image directly and never
 838  * return.  On failure, it will exit to the firmware via efi_exit() instead of
 839  * returning.
 840  */
 841 void __noreturn efi_stub_entry(efi_handle_t handle,
 842                                efi_system_table_t *sys_table_arg,
 843                                struct boot_params *boot_params)
 844 {
 845         efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
 846         struct setup_header *hdr = &boot_params->hdr;
 847         const struct linux_efi_initrd *initrd = NULL;
 848         unsigned long kernel_entry;
 849         efi_status_t status;
 850
 851         boot_params_ptr = boot_params;
 852
 853         efi_system_table = sys_table_arg;
 854         /* Check if we were booted by the EFI firmware */
 855         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 856                 efi_exit(handle, EFI_INVALID_PARAMETER);
 857
 858         if (have_unsupported_snp_features())
 859                 efi_exit(handle, EFI_UNSUPPORTED);
 860
 861         if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
 862                 efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
 863                 if (efi_dxe_table &&
 864                     efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
 865                         efi_warn("Ignoring DXE services table: invalid signature\n");
 866                         efi_dxe_table = NULL;
 867                 }
 868         }
 869
 870         /* grab the memory attributes protocol if it exists */
 871         efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
 872
 873         status = efi_setup_5level_paging();
 874         if (status != EFI_SUCCESS) {
 875                 efi_err("efi_setup_5level_paging() failed!\n");
 876                 goto fail;
 877         }
 878
 879 #ifdef CONFIG_CMDLINE_BOOL
 880         status = efi_parse_options(CONFIG_CMDLINE);
 881         if (status != EFI_SUCCESS) {
 882                 efi_err("Failed to parse options\n");
 883                 goto fail;
 884         }
 885 #endif
 886         if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 887                 unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 888                                                ((u64)boot_params->ext_cmd_line_ptr << 32));
 889                 status = efi_parse_options((char *)cmdline_paddr);
 890                 if (status != EFI_SUCCESS) {
 891                         efi_err("Failed to parse options\n");
 892                         goto fail;
 893                 }
 894         }
 895
 896         if (efi_mem_encrypt > 0)
 897                 hdr->xloadflags |= XLF_MEM_ENCRYPTION;
 898
 899         status = efi_decompress_kernel(&kernel_entry);
 900         if (status != EFI_SUCCESS) {
 901                 efi_err("Failed to decompress kernel\n");
 902                 goto fail;
 903         }
 904
 905         /*
 906          * At this point, an initrd may already have been loaded by the
 907          * bootloader and passed via bootparams. We permit an initrd loaded
 908          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 909          *
 910          * If the device path is not present, any command-line initrd=
 911          * arguments will be processed only if image is not NULL, which will be
 912          * the case only if we were loaded via the PE entry point.
 913          */
 914         status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
 915                                  &initrd);
 916         if (status != EFI_SUCCESS)
 917                 goto fail;
 918         if (initrd && initrd->size > 0) {
 919                 efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
 920                                   &boot_params->ext_ramdisk_image);
 921                 efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
 922                                   &boot_params->ext_ramdisk_size);
 923         }
 924
 925
 926         /*
 927          * If the boot loader gave us a value for secure_boot then we use that,
 928          * otherwise we ask the BIOS.
 929          */
 930         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 931                 boot_params->secure_boot = efi_get_secureboot();
 932
 933         /* Ask the firmware to clear memory on unclean shutdown */
 934         efi_enable_reset_attack_mitigation();
 935
 936         efi_random_get_seed();
 937
 938         efi_retrieve_eventlog();
 939
 940         setup_graphics(boot_params);
 941
 942         setup_efi_pci(boot_params);
 943
 944         setup_quirks(boot_params);
 945
 946         setup_unaccepted_memory();
 947
 948         status = exit_boot(boot_params, handle);
 949         if (status != EFI_SUCCESS) {
 950                 efi_err("exit_boot() failed!\n");
 951                 goto fail;
 952         }
 953
 954         /*
 955          * Call the SEV init code while still running with the firmware's
 956          * GDT/IDT, so #VC exceptions will be handled by EFI.
 957          */
 958         sev_enable(boot_params);
 959
 960         efi_5level_switch();
 961
 962         enter_kernel(kernel_entry, boot_params);
 963 fail:
 964         efi_err("efi_stub_entry() failed!\n");
 965
 966         efi_exit(handle, status);
 967 }
 968
 969 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
 970 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 971                         struct boot_params *boot_params)
 972 {
 973         extern char _bss[], _ebss[];
 974
 975         memset(_bss, 0, _ebss - _bss);
 976         efi_stub_entry(handle, sys_table_arg, boot_params);
 977 }
 978
 979 #ifndef CONFIG_EFI_MIXED
 980 extern __alias(efi_handover_entry)
 981 void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 982                       struct boot_params *boot_params);
 983
 984 extern __alias(efi_handover_entry)
 985 void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 986                       struct boot_params *boot_params);
 987 #endif
 988 #endif