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