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

   1 /*
   2  * Helper functions used by the EFI stub on multiple
   3  * architectures. This should be #included by the EFI stub
   4  * implementation files.
   5  *
   6  * Copyright 2011 Intel Corporation; author Matt Fleming
   7  *
   8  * This file is part of the Linux kernel, and is made available
   9  * under the terms of the GNU General Public License version 2.
  10  *
  11  */
  12
  13 #include <linux/efi.h>
  14 #include <asm/efi.h>
  15
  16 #include "efistub.h"
  17
  18 /*
  19  * Some firmware implementations have problems reading files in one go.
  20  * A read chunk size of 1MB seems to work for most platforms.
  21  *
  22  * Unfortunately, reading files in chunks triggers *other* bugs on some
  23  * platforms, so we provide a way to disable this workaround, which can
  24  * be done by passing "efi=nochunk" on the EFI boot stub command line.
  25  *
  26  * If you experience issues with initrd images being corrupt it's worth
  27  * trying efi=nochunk, but chunking is enabled by default because there
  28  * are far more machines that require the workaround than those that
  29  * break with it enabled.
  30  */
  31 #define EFI_READ_CHUNK_SIZE     (1024 * 1024)
  32
  33 static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
  34
  35 /*
  36  * Allow the platform to override the allocation granularity: this allows
  37  * systems that have the capability to run with a larger page size to deal
  38  * with the allocations for initrd and fdt more efficiently.
  39  */
  40 #ifndef EFI_ALLOC_ALIGN
  41 #define EFI_ALLOC_ALIGN         EFI_PAGE_SIZE
  42 #endif
  43
  44 struct file_info {
  45         efi_file_handle_t *handle;
  46         u64 size;
  47 };
  48
  49 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
  50 {
  51         char *s8;
  52
  53         for (s8 = str; *s8; s8++) {
  54                 efi_char16_t ch[2] = { 0 };
  55
  56                 ch[0] = *s8;
  57                 if (*s8 == '\n') {
  58                         efi_char16_t nl[2] = { '\r', 0 };
  59                         efi_char16_printk(sys_table_arg, nl);
  60                 }
  61
  62                 efi_char16_printk(sys_table_arg, ch);
  63         }
  64 }
  65
  66 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
  67                                 efi_memory_desc_t **map,
  68                                 unsigned long *map_size,
  69                                 unsigned long *desc_size,
  70                                 u32 *desc_ver,
  71                                 unsigned long *key_ptr)
  72 {
  73         efi_memory_desc_t *m = NULL;
  74         efi_status_t status;
  75         unsigned long key;
  76         u32 desc_version;
  77
  78         *map_size = sizeof(*m) * 32;
  79 again:
  80         /*
  81          * Add an additional efi_memory_desc_t because we're doing an
  82          * allocation which may be in a new descriptor region.
  83          */
  84         *map_size += sizeof(*m);
  85         status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
  86                                 *map_size, (void **)&m);
  87         if (status != EFI_SUCCESS)
  88                 goto fail;
  89
  90         *desc_size = 0;
  91         key = 0;
  92         status = efi_call_early(get_memory_map, map_size, m,
  93                                 &key, desc_size, &desc_version);
  94         if (status == EFI_BUFFER_TOO_SMALL) {
  95                 efi_call_early(free_pool, m);
  96                 goto again;
  97         }
  98
  99         if (status != EFI_SUCCESS)
 100                 efi_call_early(free_pool, m);
 101
 102         if (key_ptr && status == EFI_SUCCESS)
 103                 *key_ptr = key;
 104         if (desc_ver && status == EFI_SUCCESS)
 105                 *desc_ver = desc_version;
 106
 107 fail:
 108         *map = m;
 109         return status;
 110 }
 111
 112
 113 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
 114 {
 115         efi_status_t status;
 116         unsigned long map_size;
 117         unsigned long membase  = EFI_ERROR;
 118         struct efi_memory_map map;
 119         efi_memory_desc_t *md;
 120
 121         status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
 122                                     &map_size, &map.desc_size, NULL, NULL);
 123         if (status != EFI_SUCCESS)
 124                 return membase;
 125
 126         map.map_end = map.map + map_size;
 127
 128         for_each_efi_memory_desc(&map, md)
 129                 if (md->attribute & EFI_MEMORY_WB)
 130                         if (membase > md->phys_addr)
 131                                 membase = md->phys_addr;
 132
 133         efi_call_early(free_pool, map.map);
 134
 135         return membase;
 136 }
 137
 138 /*
 139  * Allocate at the highest possible address that is not above 'max'.
 140  */
 141 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 142                             unsigned long size, unsigned long align,
 143                             unsigned long *addr, unsigned long max)
 144 {
 145         unsigned long map_size, desc_size;
 146         efi_memory_desc_t *map;
 147         efi_status_t status;
 148         unsigned long nr_pages;
 149         u64 max_addr = 0;
 150         int i;
 151
 152         status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
 153                                     NULL, NULL);
 154         if (status != EFI_SUCCESS)
 155                 goto fail;
 156
 157         /*
 158          * Enforce minimum alignment that EFI requires when requesting
 159          * a specific address.  We are doing page-based allocations,
 160          * so we must be aligned to a page.
 161          */
 162         if (align < EFI_ALLOC_ALIGN)
 163                 align = EFI_ALLOC_ALIGN;
 164
 165         nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 166 again:
 167         for (i = 0; i < map_size / desc_size; i++) {
 168                 efi_memory_desc_t *desc;
 169                 unsigned long m = (unsigned long)map;
 170                 u64 start, end;
 171
 172                 desc = (efi_memory_desc_t *)(m + (i * desc_size));
 173                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 174                         continue;
 175
 176                 if (desc->num_pages < nr_pages)
 177                         continue;
 178
 179                 start = desc->phys_addr;
 180                 end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
 181
 182                 if (end > max)
 183                         end = max;
 184
 185                 if ((start + size) > end)
 186                         continue;
 187
 188                 if (round_down(end - size, align) < start)
 189                         continue;
 190
 191                 start = round_down(end - size, align);
 192
 193                 /*
 194                  * Don't allocate at 0x0. It will confuse code that
 195                  * checks pointers against NULL.
 196                  */
 197                 if (start == 0x0)
 198                         continue;
 199
 200                 if (start > max_addr)
 201                         max_addr = start;
 202         }
 203
 204         if (!max_addr)
 205                 status = EFI_NOT_FOUND;
 206         else {
 207                 status = efi_call_early(allocate_pages,
 208                                         EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 209                                         nr_pages, &max_addr);
 210                 if (status != EFI_SUCCESS) {
 211                         max = max_addr;
 212                         max_addr = 0;
 213                         goto again;
 214                 }
 215
 216                 *addr = max_addr;
 217         }
 218
 219         efi_call_early(free_pool, map);
 220 fail:
 221         return status;
 222 }
 223
 224 /*
 225  * Allocate at the lowest possible address.
 226  */
 227 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 228                            unsigned long size, unsigned long align,
 229                            unsigned long *addr)
 230 {
 231         unsigned long map_size, desc_size;
 232         efi_memory_desc_t *map;
 233         efi_status_t status;
 234         unsigned long nr_pages;
 235         int i;
 236
 237         status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
 238                                     NULL, NULL);
 239         if (status != EFI_SUCCESS)
 240                 goto fail;
 241
 242         /*
 243          * Enforce minimum alignment that EFI requires when requesting
 244          * a specific address.  We are doing page-based allocations,
 245          * so we must be aligned to a page.
 246          */
 247         if (align < EFI_ALLOC_ALIGN)
 248                 align = EFI_ALLOC_ALIGN;
 249
 250         nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 251         for (i = 0; i < map_size / desc_size; i++) {
 252                 efi_memory_desc_t *desc;
 253                 unsigned long m = (unsigned long)map;
 254                 u64 start, end;
 255
 256                 desc = (efi_memory_desc_t *)(m + (i * desc_size));
 257
 258                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 259                         continue;
 260
 261                 if (desc->num_pages < nr_pages)
 262                         continue;
 263
 264                 start = desc->phys_addr;
 265                 end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
 266
 267                 /*
 268                  * Don't allocate at 0x0. It will confuse code that
 269                  * checks pointers against NULL. Skip the first 8
 270                  * bytes so we start at a nice even number.
 271                  */
 272                 if (start == 0x0)
 273                         start += 8;
 274
 275                 start = round_up(start, align);
 276                 if ((start + size) > end)
 277                         continue;
 278
 279                 status = efi_call_early(allocate_pages,
 280                                         EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 281                                         nr_pages, &start);
 282                 if (status == EFI_SUCCESS) {
 283                         *addr = start;
 284                         break;
 285                 }
 286         }
 287
 288         if (i == map_size / desc_size)
 289                 status = EFI_NOT_FOUND;
 290
 291         efi_call_early(free_pool, map);
 292 fail:
 293         return status;
 294 }
 295
 296 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 297               unsigned long addr)
 298 {
 299         unsigned long nr_pages;
 300
 301         if (!size)
 302                 return;
 303
 304         nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 305         efi_call_early(free_pages, addr, nr_pages);
 306 }
 307
 308 /*
 309  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
 310  * option, e.g. efi=nochunk.
 311  *
 312  * It should be noted that efi= is parsed in two very different
 313  * environments, first in the early boot environment of the EFI boot
 314  * stub, and subsequently during the kernel boot.
 315  */
 316 efi_status_t efi_parse_options(char *cmdline)
 317 {
 318         char *str;
 319
 320         /*
 321          * If no EFI parameters were specified on the cmdline we've got
 322          * nothing to do.
 323          */
 324         str = strstr(cmdline, "efi=");
 325         if (!str)
 326                 return EFI_SUCCESS;
 327
 328         /* Skip ahead to first argument */
 329         str += strlen("efi=");
 330
 331         /*
 332          * Remember, because efi= is also used by the kernel we need to
 333          * skip over arguments we don't understand.
 334          */
 335         while (*str) {
 336                 if (!strncmp(str, "nochunk", 7)) {
 337                         str += strlen("nochunk");
 338                         __chunk_size = -1UL;
 339                 }
 340
 341                 /* Group words together, delimited by "," */
 342                 while (*str && *str != ',')
 343                         str++;
 344
 345                 if (*str == ',')
 346                         str++;
 347         }
 348
 349         return EFI_SUCCESS;
 350 }
 351
 352 /*
 353  * Check the cmdline for a LILO-style file= arguments.
 354  *
 355  * We only support loading a file from the same filesystem as
 356  * the kernel image.
 357  */
 358 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 359                                   efi_loaded_image_t *image,
 360                                   char *cmd_line, char *option_string,
 361                                   unsigned long max_addr,
 362                                   unsigned long *load_addr,
 363                                   unsigned long *load_size)
 364 {
 365         struct file_info *files;
 366         unsigned long file_addr;
 367         u64 file_size_total;
 368         efi_file_handle_t *fh = NULL;
 369         efi_status_t status;
 370         int nr_files;
 371         char *str;
 372         int i, j, k;
 373
 374         file_addr = 0;
 375         file_size_total = 0;
 376
 377         str = cmd_line;
 378
 379         j = 0;                  /* See close_handles */
 380
 381         if (!load_addr || !load_size)
 382                 return EFI_INVALID_PARAMETER;
 383
 384         *load_addr = 0;
 385         *load_size = 0;
 386
 387         if (!str || !*str)
 388                 return EFI_SUCCESS;
 389
 390         for (nr_files = 0; *str; nr_files++) {
 391                 str = strstr(str, option_string);
 392                 if (!str)
 393                         break;
 394
 395                 str += strlen(option_string);
 396
 397                 /* Skip any leading slashes */
 398                 while (*str == '/' || *str == '\\')
 399                         str++;
 400
 401                 while (*str && *str != ' ' && *str != '\n')
 402                         str++;
 403         }
 404
 405         if (!nr_files)
 406                 return EFI_SUCCESS;
 407
 408         status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 409                                 nr_files * sizeof(*files), (void **)&files);
 410         if (status != EFI_SUCCESS) {
 411                 pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
 412                 goto fail;
 413         }
 414
 415         str = cmd_line;
 416         for (i = 0; i < nr_files; i++) {
 417                 struct file_info *file;
 418                 efi_char16_t filename_16[256];
 419                 efi_char16_t *p;
 420
 421                 str = strstr(str, option_string);
 422                 if (!str)
 423                         break;
 424
 425                 str += strlen(option_string);
 426
 427                 file = &files[i];
 428                 p = filename_16;
 429
 430                 /* Skip any leading slashes */
 431                 while (*str == '/' || *str == '\\')
 432                         str++;
 433
 434                 while (*str && *str != ' ' && *str != '\n') {
 435                         if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
 436                                 break;
 437
 438                         if (*str == '/') {
 439                                 *p++ = '\\';
 440                                 str++;
 441                         } else {
 442                                 *p++ = *str++;
 443                         }
 444                 }
 445
 446                 *p = '\0';
 447
 448                 /* Only open the volume once. */
 449                 if (!i) {
 450                         status = efi_open_volume(sys_table_arg, image,
 451                                                  (void **)&fh);
 452                         if (status != EFI_SUCCESS)
 453                                 goto free_files;
 454                 }
 455
 456                 status = efi_file_size(sys_table_arg, fh, filename_16,
 457                                        (void **)&file->handle, &file->size);
 458                 if (status != EFI_SUCCESS)
 459                         goto close_handles;
 460
 461                 file_size_total += file->size;
 462         }
 463
 464         if (file_size_total) {
 465                 unsigned long addr;
 466
 467                 /*
 468                  * Multiple files need to be at consecutive addresses in memory,
 469                  * so allocate enough memory for all the files.  This is used
 470                  * for loading multiple files.
 471                  */
 472                 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
 473                                     &file_addr, max_addr);
 474                 if (status != EFI_SUCCESS) {
 475                         pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
 476                         goto close_handles;
 477                 }
 478
 479                 /* We've run out of free low memory. */
 480                 if (file_addr > max_addr) {
 481                         pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
 482                         status = EFI_INVALID_PARAMETER;
 483                         goto free_file_total;
 484                 }
 485
 486                 addr = file_addr;
 487                 for (j = 0; j < nr_files; j++) {
 488                         unsigned long size;
 489
 490                         size = files[j].size;
 491                         while (size) {
 492                                 unsigned long chunksize;
 493                                 if (size > __chunk_size)
 494                                         chunksize = __chunk_size;
 495                                 else
 496                                         chunksize = size;
 497
 498                                 status = efi_file_read(files[j].handle,
 499                                                        &chunksize,
 500                                                        (void *)addr);
 501                                 if (status != EFI_SUCCESS) {
 502                                         pr_efi_err(sys_table_arg, "Failed to read file\n");
 503                                         goto free_file_total;
 504                                 }
 505                                 addr += chunksize;
 506                                 size -= chunksize;
 507                         }
 508
 509                         efi_file_close(files[j].handle);
 510                 }
 511
 512         }
 513
 514         efi_call_early(free_pool, files);
 515
 516         *load_addr = file_addr;
 517         *load_size = file_size_total;
 518
 519         return status;
 520
 521 free_file_total:
 522         efi_free(sys_table_arg, file_size_total, file_addr);
 523
 524 close_handles:
 525         for (k = j; k < i; k++)
 526                 efi_file_close(files[k].handle);
 527 free_files:
 528         efi_call_early(free_pool, files);
 529 fail:
 530         *load_addr = 0;
 531         *load_size = 0;
 532
 533         return status;
 534 }
 535 /*
 536  * Relocate a kernel image, either compressed or uncompressed.
 537  * In the ARM64 case, all kernel images are currently
 538  * uncompressed, and as such when we relocate it we need to
 539  * allocate additional space for the BSS segment. Any low
 540  * memory that this function should avoid needs to be
 541  * unavailable in the EFI memory map, as if the preferred
 542  * address is not available the lowest available address will
 543  * be used.
 544  */
 545 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 546                                  unsigned long *image_addr,
 547                                  unsigned long image_size,
 548                                  unsigned long alloc_size,
 549                                  unsigned long preferred_addr,
 550                                  unsigned long alignment)
 551 {
 552         unsigned long cur_image_addr;
 553         unsigned long new_addr = 0;
 554         efi_status_t status;
 555         unsigned long nr_pages;
 556         efi_physical_addr_t efi_addr = preferred_addr;
 557
 558         if (!image_addr || !image_size || !alloc_size)
 559                 return EFI_INVALID_PARAMETER;
 560         if (alloc_size < image_size)
 561                 return EFI_INVALID_PARAMETER;
 562
 563         cur_image_addr = *image_addr;
 564
 565         /*
 566          * The EFI firmware loader could have placed the kernel image
 567          * anywhere in memory, but the kernel has restrictions on the
 568          * max physical address it can run at.  Some architectures
 569          * also have a prefered address, so first try to relocate
 570          * to the preferred address.  If that fails, allocate as low
 571          * as possible while respecting the required alignment.
 572          */
 573         nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 574         status = efi_call_early(allocate_pages,
 575                                 EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 576                                 nr_pages, &efi_addr);
 577         new_addr = efi_addr;
 578         /*
 579          * If preferred address allocation failed allocate as low as
 580          * possible.
 581          */
 582         if (status != EFI_SUCCESS) {
 583                 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
 584                                        &new_addr);
 585         }
 586         if (status != EFI_SUCCESS) {
 587                 pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
 588                 return status;
 589         }
 590
 591         /*
 592          * We know source/dest won't overlap since both memory ranges
 593          * have been allocated by UEFI, so we can safely use memcpy.
 594          */
 595         memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
 596
 597         /* Return the new address of the relocated image. */
 598         *image_addr = new_addr;
 599
 600         return status;
 601 }
 602
 603 /*
 604  * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
 605  * This overestimates for surrogates, but that is okay.
 606  */
 607 static int efi_utf8_bytes(u16 c)
 608 {
 609         return 1 + (c >= 0x80) + (c >= 0x800);
 610 }
 611
 612 /*
 613  * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
 614  */
 615 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
 616 {
 617         unsigned int c;
 618
 619         while (n--) {
 620                 c = *src++;
 621                 if (n && c >= 0xd800 && c <= 0xdbff &&
 622                     *src >= 0xdc00 && *src <= 0xdfff) {
 623                         c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
 624                         src++;
 625                         n--;
 626                 }
 627                 if (c >= 0xd800 && c <= 0xdfff)
 628                         c = 0xfffd; /* Unmatched surrogate */
 629                 if (c < 0x80) {
 630                         *dst++ = c;
 631                         continue;
 632                 }
 633                 if (c < 0x800) {
 634                         *dst++ = 0xc0 + (c >> 6);
 635                         goto t1;
 636                 }
 637                 if (c < 0x10000) {
 638                         *dst++ = 0xe0 + (c >> 12);
 639                         goto t2;
 640                 }
 641                 *dst++ = 0xf0 + (c >> 18);
 642                 *dst++ = 0x80 + ((c >> 12) & 0x3f);
 643         t2:
 644                 *dst++ = 0x80 + ((c >> 6) & 0x3f);
 645         t1:
 646                 *dst++ = 0x80 + (c & 0x3f);
 647         }
 648
 649         return dst;
 650 }
 651
 652 /*
 653  * Convert the unicode UEFI command line to ASCII to pass to kernel.
 654  * Size of memory allocated return in *cmd_line_len.
 655  * Returns NULL on error.
 656  */
 657 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
 658                           efi_loaded_image_t *image,
 659                           int *cmd_line_len)
 660 {
 661         const u16 *s2;
 662         u8 *s1 = NULL;
 663         unsigned long cmdline_addr = 0;
 664         int load_options_chars = image->load_options_size / 2; /* UTF-16 */
 665         const u16 *options = image->load_options;
 666         int options_bytes = 0;  /* UTF-8 bytes */
 667         int options_chars = 0;  /* UTF-16 chars */
 668         efi_status_t status;
 669         u16 zero = 0;
 670
 671         if (options) {
 672                 s2 = options;
 673                 while (*s2 && *s2 != '\n'
 674                        && options_chars < load_options_chars) {
 675                         options_bytes += efi_utf8_bytes(*s2++);
 676                         options_chars++;
 677                 }
 678         }
 679
 680         if (!options_chars) {
 681                 /* No command line options, so return empty string*/
 682                 options = &zero;
 683         }
 684
 685         options_bytes++;        /* NUL termination */
 686
 687         status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
 688         if (status != EFI_SUCCESS)
 689                 return NULL;
 690
 691         s1 = (u8 *)cmdline_addr;
 692         s2 = (const u16 *)options;
 693
 694         s1 = efi_utf16_to_utf8(s1, s2, options_chars);
 695         *s1 = '\0';
 696
 697         *cmd_line_len = options_bytes;
 698         return (char *)cmdline_addr;
 699 }