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