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