drivers/firmware/efi/libstub/efi-stub-helper.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Helper functions used by the EFI stub on multiple
   4  * architectures. This should be #included by the EFI stub
   5  * implementation files.
   6  *
   7  * Copyright 2011 Intel Corporation; author Matt Fleming
   8  */
   9
  10 #include <linux/efi.h>
  11 #include <asm/efi.h>
  12
  13 #include "efistub.h"
  14
  15 /*
  16  * Some firmware implementations have problems reading files in one go.
  17  * A read chunk size of 1MB seems to work for most platforms.
  18  *
  19  * Unfortunately, reading files in chunks triggers *other* bugs on some
  20  * platforms, so we provide a way to disable this workaround, which can
  21  * be done by passing "efi=nochunk" on the EFI boot stub command line.
  22  *
  23  * If you experience issues with initrd images being corrupt it's worth
  24  * trying efi=nochunk, but chunking is enabled by default because there
  25  * are far more machines that require the workaround than those that
  26  * break with it enabled.
  27  */
  28 #define EFI_READ_CHUNK_SIZE     (1024 * 1024)
  29
  30 static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
  31
  32 static int __section(.data) __nokaslr;
  33 static int __section(.data) __quiet;
  34 static int __section(.data) __novamap;
  35
  36 int __pure nokaslr(void)
  37 {
  38         return __nokaslr;
  39 }
  40 int __pure is_quiet(void)
  41 {
  42         return __quiet;
  43 }
  44 int __pure novamap(void)
  45 {
  46         return __novamap;
  47 }
  48
  49 #define EFI_MMAP_NR_SLACK_SLOTS 8
  50
  51 struct file_info {
  52         efi_file_handle_t *handle;
  53         u64 size;
  54 };
  55
  56 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
  57 {
  58         char *s8;
  59
  60         for (s8 = str; *s8; s8++) {
  61                 efi_char16_t ch[2] = { 0 };
  62
  63                 ch[0] = *s8;
  64                 if (*s8 == '\n') {
  65                         efi_char16_t nl[2] = { '\r', 0 };
  66                         efi_char16_printk(sys_table_arg, nl);
  67                 }
  68
  69                 efi_char16_printk(sys_table_arg, ch);
  70         }
  71 }
  72
  73 static inline bool mmap_has_headroom(unsigned long buff_size,
  74                                      unsigned long map_size,
  75                                      unsigned long desc_size)
  76 {
  77         unsigned long slack = buff_size - map_size;
  78
  79         return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
  80 }
  81
  82 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
  83                                 struct efi_boot_memmap *map)
  84 {
  85         efi_memory_desc_t *m = NULL;
  86         efi_status_t status;
  87         unsigned long key;
  88         u32 desc_version;
  89
  90         *map->desc_size =       sizeof(*m);
  91         *map->map_size =        *map->desc_size * 32;
  92         *map->buff_size =       *map->map_size;
  93 again:
  94         status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
  95                                 *map->map_size, (void **)&m);
  96         if (status != EFI_SUCCESS)
  97                 goto fail;
  98
  99         *map->desc_size = 0;
 100         key = 0;
 101         status = efi_call_early(get_memory_map, map->map_size, m,
 102                                 &key, map->desc_size, &desc_version);
 103         if (status == EFI_BUFFER_TOO_SMALL ||
 104             !mmap_has_headroom(*map->buff_size, *map->map_size,
 105                                *map->desc_size)) {
 106                 efi_call_early(free_pool, m);
 107                 /*
 108                  * Make sure there is some entries of headroom so that the
 109                  * buffer can be reused for a new map after allocations are
 110                  * no longer permitted.  Its unlikely that the map will grow to
 111                  * exceed this headroom once we are ready to trigger
 112                  * ExitBootServices()
 113                  */
 114                 *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
 115                 *map->buff_size = *map->map_size;
 116                 goto again;
 117         }
 118
 119         if (status != EFI_SUCCESS)
 120                 efi_call_early(free_pool, m);
 121
 122         if (map->key_ptr && status == EFI_SUCCESS)
 123                 *map->key_ptr = key;
 124         if (map->desc_ver && status == EFI_SUCCESS)
 125                 *map->desc_ver = desc_version;
 126
 127 fail:
 128         *map->map = m;
 129         return status;
 130 }
 131
 132
 133 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
 134 {
 135         efi_status_t status;
 136         unsigned long map_size, buff_size;
 137         unsigned long membase  = EFI_ERROR;
 138         struct efi_memory_map map;
 139         efi_memory_desc_t *md;
 140         struct efi_boot_memmap boot_map;
 141
 142         boot_map.map =          (efi_memory_desc_t **)&map.map;
 143         boot_map.map_size =     &map_size;
 144         boot_map.desc_size =    &map.desc_size;
 145         boot_map.desc_ver =     NULL;
 146         boot_map.key_ptr =      NULL;
 147         boot_map.buff_size =    &buff_size;
 148
 149         status = efi_get_memory_map(sys_table_arg, &boot_map);
 150         if (status != EFI_SUCCESS)
 151                 return membase;
 152
 153         map.map_end = map.map + map_size;
 154
 155         for_each_efi_memory_desc_in_map(&map, md) {
 156                 if (md->attribute & EFI_MEMORY_WB) {
 157                         if (membase > md->phys_addr)
 158                                 membase = md->phys_addr;
 159                 }
 160         }
 161
 162         efi_call_early(free_pool, map.map);
 163
 164         return membase;
 165 }
 166
 167 /*
 168  * Allocate at the highest possible address that is not above 'max'.
 169  */
 170 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 171                             unsigned long size, unsigned long align,
 172                             unsigned long *addr, unsigned long max)
 173 {
 174         unsigned long map_size, desc_size, buff_size;
 175         efi_memory_desc_t *map;
 176         efi_status_t status;
 177         unsigned long nr_pages;
 178         u64 max_addr = 0;
 179         int i;
 180         struct efi_boot_memmap boot_map;
 181
 182         boot_map.map =          &map;
 183         boot_map.map_size =     &map_size;
 184         boot_map.desc_size =    &desc_size;
 185         boot_map.desc_ver =     NULL;
 186         boot_map.key_ptr =      NULL;
 187         boot_map.buff_size =    &buff_size;
 188
 189         status = efi_get_memory_map(sys_table_arg, &boot_map);
 190         if (status != EFI_SUCCESS)
 191                 goto fail;
 192
 193         /*
 194          * Enforce minimum alignment that EFI or Linux requires when
 195          * requesting a specific address.  We are doing page-based (or
 196          * larger) allocations, and both the address and size must meet
 197          * alignment constraints.
 198          */
 199         if (align < EFI_ALLOC_ALIGN)
 200                 align = EFI_ALLOC_ALIGN;
 201
 202         size = round_up(size, EFI_ALLOC_ALIGN);
 203         nr_pages = size / EFI_PAGE_SIZE;
 204 again:
 205         for (i = 0; i < map_size / desc_size; i++) {
 206                 efi_memory_desc_t *desc;
 207                 unsigned long m = (unsigned long)map;
 208                 u64 start, end;
 209
 210                 desc = efi_early_memdesc_ptr(m, desc_size, i);
 211                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 212                         continue;
 213
 214                 if (desc->num_pages < nr_pages)
 215                         continue;
 216
 217                 start = desc->phys_addr;
 218                 end = start + desc->num_pages * EFI_PAGE_SIZE;
 219
 220                 if (end > max)
 221                         end = max;
 222
 223                 if ((start + size) > end)
 224                         continue;
 225
 226                 if (round_down(end - size, align) < start)
 227                         continue;
 228
 229                 start = round_down(end - size, align);
 230
 231                 /*
 232                  * Don't allocate at 0x0. It will confuse code that
 233                  * checks pointers against NULL.
 234                  */
 235                 if (start == 0x0)
 236                         continue;
 237
 238                 if (start > max_addr)
 239                         max_addr = start;
 240         }
 241
 242         if (!max_addr)
 243                 status = EFI_NOT_FOUND;
 244         else {
 245                 status = efi_call_early(allocate_pages,
 246                                         EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 247                                         nr_pages, &max_addr);
 248                 if (status != EFI_SUCCESS) {
 249                         max = max_addr;
 250                         max_addr = 0;
 251                         goto again;
 252                 }
 253
 254                 *addr = max_addr;
 255         }
 256
 257         efi_call_early(free_pool, map);
 258 fail:
 259         return status;
 260 }
 261
 262 /*
 263  * Allocate at the lowest possible address.
 264  */
 265 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 266                            unsigned long size, unsigned long align,
 267                            unsigned long *addr)
 268 {
 269         unsigned long map_size, desc_size, buff_size;
 270         efi_memory_desc_t *map;
 271         efi_status_t status;
 272         unsigned long nr_pages;
 273         int i;
 274         struct efi_boot_memmap boot_map;
 275
 276         boot_map.map =          &map;
 277         boot_map.map_size =     &map_size;
 278         boot_map.desc_size =    &desc_size;
 279         boot_map.desc_ver =     NULL;
 280         boot_map.key_ptr =      NULL;
 281         boot_map.buff_size =    &buff_size;
 282
 283         status = efi_get_memory_map(sys_table_arg, &boot_map);
 284         if (status != EFI_SUCCESS)
 285                 goto fail;
 286
 287         /*
 288          * Enforce minimum alignment that EFI or Linux requires when
 289          * requesting a specific address.  We are doing page-based (or
 290          * larger) allocations, and both the address and size must meet
 291          * alignment constraints.
 292          */
 293         if (align < EFI_ALLOC_ALIGN)
 294                 align = EFI_ALLOC_ALIGN;
 295
 296         size = round_up(size, EFI_ALLOC_ALIGN);
 297         nr_pages = size / EFI_PAGE_SIZE;
 298         for (i = 0; i < map_size / desc_size; i++) {
 299                 efi_memory_desc_t *desc;
 300                 unsigned long m = (unsigned long)map;
 301                 u64 start, end;
 302
 303                 desc = efi_early_memdesc_ptr(m, desc_size, i);
 304
 305                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 306                         continue;
 307
 308                 if (desc->num_pages < nr_pages)
 309                         continue;
 310
 311                 start = desc->phys_addr;
 312                 end = start + desc->num_pages * EFI_PAGE_SIZE;
 313
 314                 /*
 315                  * Don't allocate at 0x0. It will confuse code that
 316                  * checks pointers against NULL. Skip the first 8
 317                  * bytes so we start at a nice even number.
 318                  */
 319                 if (start == 0x0)
 320                         start += 8;
 321
 322                 start = round_up(start, align);
 323                 if ((start + size) > end)
 324                         continue;
 325
 326                 status = efi_call_early(allocate_pages,
 327                                         EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 328                                         nr_pages, &start);
 329                 if (status == EFI_SUCCESS) {
 330                         *addr = start;
 331                         break;
 332                 }
 333         }
 334
 335         if (i == map_size / desc_size)
 336                 status = EFI_NOT_FOUND;
 337
 338         efi_call_early(free_pool, map);
 339 fail:
 340         return status;
 341 }
 342
 343 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 344               unsigned long addr)
 345 {
 346         unsigned long nr_pages;
 347
 348         if (!size)
 349                 return;
 350
 351         nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 352         efi_call_early(free_pages, addr, nr_pages);
 353 }
 354
 355 static efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
 356                                   efi_char16_t *filename_16, void **handle,
 357                                   u64 *file_sz)
 358 {
 359         efi_file_handle_t *h, *fh = __fh;
 360         efi_file_info_t *info;
 361         efi_status_t status;
 362         efi_guid_t info_guid = EFI_FILE_INFO_ID;
 363         unsigned long info_sz;
 364
 365         status = efi_call_proto(efi_file_handle, open, fh, &h, filename_16,
 366                                 EFI_FILE_MODE_READ, (u64)0);
 367         if (status != EFI_SUCCESS) {
 368                 efi_printk(sys_table_arg, "Failed to open file: ");
 369                 efi_char16_printk(sys_table_arg, filename_16);
 370                 efi_printk(sys_table_arg, "\n");
 371                 return status;
 372         }
 373
 374         *handle = h;
 375
 376         info_sz = 0;
 377         status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
 378                                 &info_sz, NULL);
 379         if (status != EFI_BUFFER_TOO_SMALL) {
 380                 efi_printk(sys_table_arg, "Failed to get file info size\n");
 381                 return status;
 382         }
 383
 384 grow:
 385         status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 386                                 info_sz, (void **)&info);
 387         if (status != EFI_SUCCESS) {
 388                 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
 389                 return status;
 390         }
 391
 392         status = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
 393                                 &info_sz, info);
 394         if (status == EFI_BUFFER_TOO_SMALL) {
 395                 efi_call_early(free_pool, info);
 396                 goto grow;
 397         }
 398
 399         *file_sz = info->file_size;
 400         efi_call_early(free_pool, info);
 401
 402         if (status != EFI_SUCCESS)
 403                 efi_printk(sys_table_arg, "Failed to get initrd info\n");
 404
 405         return status;
 406 }
 407
 408 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
 409 {
 410         return efi_call_proto(efi_file_handle, read, handle, size, addr);
 411 }
 412
 413 static efi_status_t efi_file_close(void *handle)
 414 {
 415         return efi_call_proto(efi_file_handle, close, handle);
 416 }
 417
 418 static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 419                                     efi_loaded_image_t *image,
 420                                     efi_file_handle_t **__fh)
 421 {
 422         efi_file_io_interface_t *io;
 423         efi_file_handle_t *fh;
 424         efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
 425         efi_status_t status;
 426         void *handle = (void *)(unsigned long)efi_table_attr(efi_loaded_image,
 427                                                              device_handle,
 428                                                              image);
 429
 430         status = efi_call_early(handle_protocol, handle,
 431                                 &fs_proto, (void **)&io);
 432         if (status != EFI_SUCCESS) {
 433                 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
 434                 return status;
 435         }
 436
 437         status = efi_call_proto(efi_file_io_interface, open_volume, io, &fh);
 438         if (status != EFI_SUCCESS)
 439                 efi_printk(sys_table_arg, "Failed to open volume\n");
 440         else
 441                 *__fh = fh;
 442
 443         return status;
 444 }
 445
 446 /*
 447  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
 448  * option, e.g. efi=nochunk.
 449  *
 450  * It should be noted that efi= is parsed in two very different
 451  * environments, first in the early boot environment of the EFI boot
 452  * stub, and subsequently during the kernel boot.
 453  */
 454 efi_status_t efi_parse_options(char const *cmdline)
 455 {
 456         char *str;
 457
 458         str = strstr(cmdline, "nokaslr");
 459         if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
 460                 __nokaslr = 1;
 461
 462         str = strstr(cmdline, "quiet");
 463         if (str == cmdline || (str && str > cmdline && *(str - 1) == ' '))
 464                 __quiet = 1;
 465
 466         /*
 467          * If no EFI parameters were specified on the cmdline we've got
 468          * nothing to do.
 469          */
 470         str = strstr(cmdline, "efi=");
 471         if (!str)
 472                 return EFI_SUCCESS;
 473
 474         /* Skip ahead to first argument */
 475         str += strlen("efi=");
 476
 477         /*
 478          * Remember, because efi= is also used by the kernel we need to
 479          * skip over arguments we don't understand.
 480          */
 481         while (*str && *str != ' ') {
 482                 if (!strncmp(str, "nochunk", 7)) {
 483                         str += strlen("nochunk");
 484                         __chunk_size = -1UL;
 485                 }
 486
 487                 if (!strncmp(str, "novamap", 7)) {
 488                         str += strlen("novamap");
 489                         __novamap = 1;
 490                 }
 491
 492                 /* Group words together, delimited by "," */
 493                 while (*str && *str != ' ' && *str != ',')
 494                         str++;
 495
 496                 if (*str == ',')
 497                         str++;
 498         }
 499
 500         return EFI_SUCCESS;
 501 }
 502
 503 /*
 504  * Check the cmdline for a LILO-style file= arguments.
 505  *
 506  * We only support loading a file from the same filesystem as
 507  * the kernel image.
 508  */
 509 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 510                                   efi_loaded_image_t *image,
 511                                   char *cmd_line, char *option_string,
 512                                   unsigned long max_addr,
 513                                   unsigned long *load_addr,
 514                                   unsigned long *load_size)
 515 {
 516         struct file_info *files;
 517         unsigned long file_addr;
 518         u64 file_size_total;
 519         efi_file_handle_t *fh = NULL;
 520         efi_status_t status;
 521         int nr_files;
 522         char *str;
 523         int i, j, k;
 524
 525         file_addr = 0;
 526         file_size_total = 0;
 527
 528         str = cmd_line;
 529
 530         j = 0;                  /* See close_handles */
 531
 532         if (!load_addr || !load_size)
 533                 return EFI_INVALID_PARAMETER;
 534
 535         *load_addr = 0;
 536         *load_size = 0;
 537
 538         if (!str || !*str)
 539                 return EFI_SUCCESS;
 540
 541         for (nr_files = 0; *str; nr_files++) {
 542                 str = strstr(str, option_string);
 543                 if (!str)
 544                         break;
 545
 546                 str += strlen(option_string);
 547
 548                 /* Skip any leading slashes */
 549                 while (*str == '/' || *str == '\\')
 550                         str++;
 551
 552                 while (*str && *str != ' ' && *str != '\n')
 553                         str++;
 554         }
 555
 556         if (!nr_files)
 557                 return EFI_SUCCESS;
 558
 559         status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 560                                 nr_files * sizeof(*files), (void **)&files);
 561         if (status != EFI_SUCCESS) {
 562                 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
 563                 goto fail;
 564         }
 565
 566         str = cmd_line;
 567         for (i = 0; i < nr_files; i++) {
 568                 struct file_info *file;
 569                 efi_char16_t filename_16[256];
 570                 efi_char16_t *p;
 571
 572                 str = strstr(str, option_string);
 573                 if (!str)
 574                         break;
 575
 576                 str += strlen(option_string);
 577
 578                 file = &files[i];
 579                 p = filename_16;
 580
 581                 /* Skip any leading slashes */
 582                 while (*str == '/' || *str == '\\')
 583                         str++;
 584
 585                 while (*str && *str != ' ' && *str != '\n') {
 586                         if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
 587                                 break;
 588
 589                         if (*str == '/') {
 590                                 *p++ = '\\';
 591                                 str++;
 592                         } else {
 593                                 *p++ = *str++;
 594                         }
 595                 }
 596
 597                 *p = '\0';
 598
 599                 /* Only open the volume once. */
 600                 if (!i) {
 601                         status = efi_open_volume(sys_table_arg, image, &fh);
 602                         if (status != EFI_SUCCESS)
 603                                 goto free_files;
 604                 }
 605
 606                 status = efi_file_size(sys_table_arg, fh, filename_16,
 607                                        (void **)&file->handle, &file->size);
 608                 if (status != EFI_SUCCESS)
 609                         goto close_handles;
 610
 611                 file_size_total += file->size;
 612         }
 613
 614         if (file_size_total) {
 615                 unsigned long addr;
 616
 617                 /*
 618                  * Multiple files need to be at consecutive addresses in memory,
 619                  * so allocate enough memory for all the files.  This is used
 620                  * for loading multiple files.
 621                  */
 622                 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
 623                                     &file_addr, max_addr);
 624                 if (status != EFI_SUCCESS) {
 625                         pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
 626                         goto close_handles;
 627                 }
 628
 629                 /* We've run out of free low memory. */
 630                 if (file_addr > max_addr) {
 631                         pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
 632                         status = EFI_INVALID_PARAMETER;
 633                         goto free_file_total;
 634                 }
 635
 636                 addr = file_addr;
 637                 for (j = 0; j < nr_files; j++) {
 638                         unsigned long size;
 639
 640                         size = files[j].size;
 641                         while (size) {
 642                                 unsigned long chunksize;
 643
 644                                 if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
 645                                         chunksize = __chunk_size;
 646                                 else
 647                                         chunksize = size;
 648
 649                                 status = efi_file_read(files[j].handle,
 650                                                        &chunksize,
 651                                                        (void *)addr);
 652                                 if (status != EFI_SUCCESS) {
 653                                         pr_efi_err(sys_table_arg, "Failed to read file\n");
 654                                         goto free_file_total;
 655                                 }
 656                                 addr += chunksize;
 657                                 size -= chunksize;
 658                         }
 659
 660                         efi_file_close(files[j].handle);
 661                 }
 662
 663         }
 664
 665         efi_call_early(free_pool, files);
 666
 667         *load_addr = file_addr;
 668         *load_size = file_size_total;
 669
 670         return status;
 671
 672 free_file_total:
 673         efi_free(sys_table_arg, file_size_total, file_addr);
 674
 675 close_handles:
 676         for (k = j; k < i; k++)
 677                 efi_file_close(files[k].handle);
 678 free_files:
 679         efi_call_early(free_pool, files);
 680 fail:
 681         *load_addr = 0;
 682         *load_size = 0;
 683
 684         return status;
 685 }
 686 /*
 687  * Relocate a kernel image, either compressed or uncompressed.
 688  * In the ARM64 case, all kernel images are currently
 689  * uncompressed, and as such when we relocate it we need to
 690  * allocate additional space for the BSS segment. Any low
 691  * memory that this function should avoid needs to be
 692  * unavailable in the EFI memory map, as if the preferred
 693  * address is not available the lowest available address will
 694  * be used.
 695  */
 696 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 697                                  unsigned long *image_addr,
 698                                  unsigned long image_size,
 699                                  unsigned long alloc_size,
 700                                  unsigned long preferred_addr,
 701                                  unsigned long alignment)
 702 {
 703         unsigned long cur_image_addr;
 704         unsigned long new_addr = 0;
 705         efi_status_t status;
 706         unsigned long nr_pages;
 707         efi_physical_addr_t efi_addr = preferred_addr;
 708
 709         if (!image_addr || !image_size || !alloc_size)
 710                 return EFI_INVALID_PARAMETER;
 711         if (alloc_size < image_size)
 712                 return EFI_INVALID_PARAMETER;
 713
 714         cur_image_addr = *image_addr;
 715
 716         /*
 717          * The EFI firmware loader could have placed the kernel image
 718          * anywhere in memory, but the kernel has restrictions on the
 719          * max physical address it can run at.  Some architectures
 720          * also have a prefered address, so first try to relocate
 721          * to the preferred address.  If that fails, allocate as low
 722          * as possible while respecting the required alignment.
 723          */
 724         nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 725         status = efi_call_early(allocate_pages,
 726                                 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 727                                 nr_pages, &efi_addr);
 728         new_addr = efi_addr;
 729         /*
 730          * If preferred address allocation failed allocate as low as
 731          * possible.
 732          */
 733         if (status != EFI_SUCCESS) {
 734                 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
 735                                        &new_addr);
 736         }
 737         if (status != EFI_SUCCESS) {
 738                 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
 739                 return status;
 740         }
 741
 742         /*
 743          * We know source/dest won't overlap since both memory ranges
 744          * have been allocated by UEFI, so we can safely use memcpy.
 745          */
 746         memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
 747
 748         /* Return the new address of the relocated image. */
 749         *image_addr = new_addr;
 750
 751         return status;
 752 }
 753
 754 /*
 755  * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
 756  * This overestimates for surrogates, but that is okay.
 757  */
 758 static int efi_utf8_bytes(u16 c)
 759 {
 760         return 1 + (c >= 0x80) + (c >= 0x800);
 761 }
 762
 763 /*
 764  * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
 765  */
 766 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
 767 {
 768         unsigned int c;
 769
 770         while (n--) {
 771                 c = *src++;
 772                 if (n && c >= 0xd800 && c <= 0xdbff &&
 773                     *src >= 0xdc00 && *src <= 0xdfff) {
 774                         c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
 775                         src++;
 776                         n--;
 777                 }
 778                 if (c >= 0xd800 && c <= 0xdfff)
 779                         c = 0xfffd; /* Unmatched surrogate */
 780                 if (c < 0x80) {
 781                         *dst++ = c;
 782                         continue;
 783                 }
 784                 if (c < 0x800) {
 785                         *dst++ = 0xc0 + (c >> 6);
 786                         goto t1;
 787                 }
 788                 if (c < 0x10000) {
 789                         *dst++ = 0xe0 + (c >> 12);
 790                         goto t2;
 791                 }
 792                 *dst++ = 0xf0 + (c >> 18);
 793                 *dst++ = 0x80 + ((c >> 12) & 0x3f);
 794         t2:
 795                 *dst++ = 0x80 + ((c >> 6) & 0x3f);
 796         t1:
 797                 *dst++ = 0x80 + (c & 0x3f);
 798         }
 799
 800         return dst;
 801 }
 802
 803 #ifndef MAX_CMDLINE_ADDRESS
 804 #define MAX_CMDLINE_ADDRESS     ULONG_MAX
 805 #endif
 806
 807 /*
 808  * Convert the unicode UEFI command line to ASCII to pass to kernel.
 809  * Size of memory allocated return in *cmd_line_len.
 810  * Returns NULL on error.
 811  */
 812 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
 813                           efi_loaded_image_t *image,
 814                           int *cmd_line_len)
 815 {
 816         const u16 *s2;
 817         u8 *s1 = NULL;
 818         unsigned long cmdline_addr = 0;
 819         int load_options_chars = image->load_options_size / 2; /* UTF-16 */
 820         const u16 *options = image->load_options;
 821         int options_bytes = 0;  /* UTF-8 bytes */
 822         int options_chars = 0;  /* UTF-16 chars */
 823         efi_status_t status;
 824         u16 zero = 0;
 825
 826         if (options) {
 827                 s2 = options;
 828                 while (*s2 && *s2 != '\n'
 829                        && options_chars < load_options_chars) {
 830                         options_bytes += efi_utf8_bytes(*s2++);
 831                         options_chars++;
 832                 }
 833         }
 834
 835         if (!options_chars) {
 836                 /* No command line options, so return empty string*/
 837                 options = &zero;
 838         }
 839
 840         options_bytes++;        /* NUL termination */
 841
 842         status = efi_high_alloc(sys_table_arg, options_bytes, 0,
 843                                 &cmdline_addr, MAX_CMDLINE_ADDRESS);
 844         if (status != EFI_SUCCESS)
 845                 return NULL;
 846
 847         s1 = (u8 *)cmdline_addr;
 848         s2 = (const u16 *)options;
 849
 850         s1 = efi_utf16_to_utf8(s1, s2, options_chars);
 851         *s1 = '\0';
 852
 853         *cmd_line_len = options_bytes;
 854         return (char *)cmdline_addr;
 855 }
 856
 857 /*
 858  * Handle calling ExitBootServices according to the requirements set out by the
 859  * spec.  Obtains the current memory map, and returns that info after calling
 860  * ExitBootServices.  The client must specify a function to perform any
 861  * processing of the memory map data prior to ExitBootServices.  A client
 862  * specific structure may be passed to the function via priv.  The client
 863  * function may be called multiple times.
 864  */
 865 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
 866                                     void *handle,
 867                                     struct efi_boot_memmap *map,
 868                                     void *priv,
 869                                     efi_exit_boot_map_processing priv_func)
 870 {
 871         efi_status_t status;
 872
 873         status = efi_get_memory_map(sys_table_arg, map);
 874
 875         if (status != EFI_SUCCESS)
 876                 goto fail;
 877
 878         status = priv_func(sys_table_arg, map, priv);
 879         if (status != EFI_SUCCESS)
 880                 goto free_map;
 881
 882         status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
 883
 884         if (status == EFI_INVALID_PARAMETER) {
 885                 /*
 886                  * The memory map changed between efi_get_memory_map() and
 887                  * exit_boot_services().  Per the UEFI Spec v2.6, Section 6.4:
 888                  * EFI_BOOT_SERVICES.ExitBootServices we need to get the
 889                  * updated map, and try again.  The spec implies one retry
 890                  * should be sufficent, which is confirmed against the EDK2
 891                  * implementation.  Per the spec, we can only invoke
 892                  * get_memory_map() and exit_boot_services() - we cannot alloc
 893                  * so efi_get_memory_map() cannot be used, and we must reuse
 894                  * the buffer.  For all practical purposes, the headroom in the
 895                  * buffer should account for any changes in the map so the call
 896                  * to get_memory_map() is expected to succeed here.
 897                  */
 898                 *map->map_size = *map->buff_size;
 899                 status = efi_call_early(get_memory_map,
 900                                         map->map_size,
 901                                         *map->map,
 902                                         map->key_ptr,
 903                                         map->desc_size,
 904                                         map->desc_ver);
 905
 906                 /* exit_boot_services() was called, thus cannot free */
 907                 if (status != EFI_SUCCESS)
 908                         goto fail;
 909
 910                 status = priv_func(sys_table_arg, map, priv);
 911                 /* exit_boot_services() was called, thus cannot free */
 912                 if (status != EFI_SUCCESS)
 913                         goto fail;
 914
 915                 status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
 916         }
 917
 918         /* exit_boot_services() was called, thus cannot free */
 919         if (status != EFI_SUCCESS)
 920                 goto fail;
 921
 922         return EFI_SUCCESS;
 923
 924 free_map:
 925         efi_call_early(free_pool, *map->map);
 926 fail:
 927         return status;
 928 }
 929
 930 #define GET_EFI_CONFIG_TABLE(bits)                                      \
 931 static void *get_efi_config_table##bits(efi_system_table_t *_sys_table, \
 932                                         efi_guid_t guid)                \
 933 {                                                                       \
 934         efi_system_table_##bits##_t *sys_table;                         \
 935         efi_config_table_##bits##_t *tables;                            \
 936         int i;                                                          \
 937                                                                         \
 938         sys_table = (typeof(sys_table))_sys_table;                      \
 939         tables = (typeof(tables))(unsigned long)sys_table->tables;      \
 940                                                                         \
 941         for (i = 0; i < sys_table->nr_tables; i++) {                    \
 942                 if (efi_guidcmp(tables[i].guid, guid) != 0)             \
 943                         continue;                                       \
 944                                                                         \
 945                 return (void *)(unsigned long)tables[i].table;          \
 946         }                                                               \
 947                                                                         \
 948         return NULL;                                                    \
 949 }
 950 GET_EFI_CONFIG_TABLE(32)
 951 GET_EFI_CONFIG_TABLE(64)
 952
 953 void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid)
 954 {
 955         if (efi_is_64bit())
 956                 return get_efi_config_table64(sys_table, guid);
 957         else
 958                 return get_efi_config_table32(sys_table, guid);
 959 }