drivers/firmware/efi/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 #define EFI_READ_CHUNK_SIZE     (1024 * 1024)
  13
  14 struct file_info {
  15         efi_file_handle_t *handle;
  16         u64 size;
  17 };
  18
  19 static void efi_printk(efi_system_table_t *sys_table_arg, char *str)
  20 {
  21         char *s8;
  22
  23         for (s8 = str; *s8; s8++) {
  24                 efi_char16_t ch[2] = { 0 };
  25
  26                 ch[0] = *s8;
  27                 if (*s8 == '\n') {
  28                         efi_char16_t nl[2] = { '\r', 0 };
  29                         efi_char16_printk(sys_table_arg, nl);
  30                 }
  31
  32                 efi_char16_printk(sys_table_arg, ch);
  33         }
  34 }
  35
  36
  37 static efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
  38                                        efi_memory_desc_t **map,
  39                                        unsigned long *map_size,
  40                                        unsigned long *desc_size,
  41                                        u32 *desc_ver,
  42                                        unsigned long *key_ptr)
  43 {
  44         efi_memory_desc_t *m = NULL;
  45         efi_status_t status;
  46         unsigned long key;
  47         u32 desc_version;
  48
  49         *map_size = sizeof(*m) * 32;
  50 again:
  51         /*
  52          * Add an additional efi_memory_desc_t because we're doing an
  53          * allocation which may be in a new descriptor region.
  54          */
  55         *map_size += sizeof(*m);
  56         status = efi_early->call(efi_early->allocate_pool, EFI_LOADER_DATA,
  57                                  *map_size, (void **)&m);
  58         if (status != EFI_SUCCESS)
  59                 goto fail;
  60
  61         *desc_size = 0;
  62         key = 0;
  63         status = efi_early->call(efi_early->get_memory_map, map_size, m,
  64                                  &key, desc_size, &desc_version);
  65         if (status == EFI_BUFFER_TOO_SMALL) {
  66                 efi_early->call(efi_early->free_pool, m);
  67                 goto again;
  68         }
  69
  70         if (status != EFI_SUCCESS)
  71                 efi_early->call(efi_early->free_pool, m);
  72
  73         if (key_ptr && status == EFI_SUCCESS)
  74                 *key_ptr = key;
  75         if (desc_ver && status == EFI_SUCCESS)
  76                 *desc_ver = desc_version;
  77
  78 fail:
  79         *map = m;
  80         return status;
  81 }
  82
  83 /*
  84  * Allocate at the highest possible address that is not above 'max'.
  85  */
  86 static efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
  87                                unsigned long size, unsigned long align,
  88                                unsigned long *addr, unsigned long max)
  89 {
  90         unsigned long map_size, desc_size;
  91         efi_memory_desc_t *map;
  92         efi_status_t status;
  93         unsigned long nr_pages;
  94         u64 max_addr = 0;
  95         int i;
  96
  97         status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
  98                                     NULL, NULL);
  99         if (status != EFI_SUCCESS)
 100                 goto fail;
 101
 102         /*
 103          * Enforce minimum alignment that EFI requires when requesting
 104          * a specific address.  We are doing page-based allocations,
 105          * so we must be aligned to a page.
 106          */
 107         if (align < EFI_PAGE_SIZE)
 108                 align = EFI_PAGE_SIZE;
 109
 110         nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 111 again:
 112         for (i = 0; i < map_size / desc_size; i++) {
 113                 efi_memory_desc_t *desc;
 114                 unsigned long m = (unsigned long)map;
 115                 u64 start, end;
 116
 117                 desc = (efi_memory_desc_t *)(m + (i * desc_size));
 118                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 119                         continue;
 120
 121                 if (desc->num_pages < nr_pages)
 122                         continue;
 123
 124                 start = desc->phys_addr;
 125                 end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
 126
 127                 if ((start + size) > end || (start + size) > max)
 128                         continue;
 129
 130                 if (end - size > max)
 131                         end = max;
 132
 133                 if (round_down(end - size, align) < start)
 134                         continue;
 135
 136                 start = round_down(end - size, align);
 137
 138                 /*
 139                  * Don't allocate at 0x0. It will confuse code that
 140                  * checks pointers against NULL.
 141                  */
 142                 if (start == 0x0)
 143                         continue;
 144
 145                 if (start > max_addr)
 146                         max_addr = start;
 147         }
 148
 149         if (!max_addr)
 150                 status = EFI_NOT_FOUND;
 151         else {
 152                 status = efi_early->call(efi_early->allocate_pages,
 153                                          EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 154                                          nr_pages, &max_addr);
 155                 if (status != EFI_SUCCESS) {
 156                         max = max_addr;
 157                         max_addr = 0;
 158                         goto again;
 159                 }
 160
 161                 *addr = max_addr;
 162         }
 163
 164         efi_early->call(efi_early->free_pool, map);
 165 fail:
 166         return status;
 167 }
 168
 169 /*
 170  * Allocate at the lowest possible address.
 171  */
 172 static efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 173                               unsigned long size, unsigned long align,
 174                               unsigned long *addr)
 175 {
 176         unsigned long map_size, desc_size;
 177         efi_memory_desc_t *map;
 178         efi_status_t status;
 179         unsigned long nr_pages;
 180         int i;
 181
 182         status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
 183                                     NULL, NULL);
 184         if (status != EFI_SUCCESS)
 185                 goto fail;
 186
 187         /*
 188          * Enforce minimum alignment that EFI requires when requesting
 189          * a specific address.  We are doing page-based allocations,
 190          * so we must be aligned to a page.
 191          */
 192         if (align < EFI_PAGE_SIZE)
 193                 align = EFI_PAGE_SIZE;
 194
 195         nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 196         for (i = 0; i < map_size / desc_size; i++) {
 197                 efi_memory_desc_t *desc;
 198                 unsigned long m = (unsigned long)map;
 199                 u64 start, end;
 200
 201                 desc = (efi_memory_desc_t *)(m + (i * desc_size));
 202
 203                 if (desc->type != EFI_CONVENTIONAL_MEMORY)
 204                         continue;
 205
 206                 if (desc->num_pages < nr_pages)
 207                         continue;
 208
 209                 start = desc->phys_addr;
 210                 end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
 211
 212                 /*
 213                  * Don't allocate at 0x0. It will confuse code that
 214                  * checks pointers against NULL. Skip the first 8
 215                  * bytes so we start at a nice even number.
 216                  */
 217                 if (start == 0x0)
 218                         start += 8;
 219
 220                 start = round_up(start, align);
 221                 if ((start + size) > end)
 222                         continue;
 223
 224                 status = efi_early->call(efi_early->allocate_pages,
 225                                          EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 226                                          nr_pages, &start);
 227                 if (status == EFI_SUCCESS) {
 228                         *addr = start;
 229                         break;
 230                 }
 231         }
 232
 233         if (i == map_size / desc_size)
 234                 status = EFI_NOT_FOUND;
 235
 236         efi_early->call(efi_early->free_pool, map);
 237 fail:
 238         return status;
 239 }
 240
 241 static void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 242                      unsigned long addr)
 243 {
 244         unsigned long nr_pages;
 245
 246         if (!size)
 247                 return;
 248
 249         nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 250         efi_early->call(efi_early->free_pages, addr, nr_pages);
 251 }
 252
 253
 254 /*
 255  * Check the cmdline for a LILO-style file= arguments.
 256  *
 257  * We only support loading a file from the same filesystem as
 258  * the kernel image.
 259  */
 260 static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 261                                          efi_loaded_image_t *image,
 262                                          char *cmd_line, char *option_string,
 263                                          unsigned long max_addr,
 264                                          unsigned long *load_addr,
 265                                          unsigned long *load_size)
 266 {
 267         struct file_info *files;
 268         unsigned long file_addr;
 269         u64 file_size_total;
 270         efi_file_handle_t *fh;
 271         efi_status_t status;
 272         int nr_files;
 273         char *str;
 274         int i, j, k;
 275
 276         file_addr = 0;
 277         file_size_total = 0;
 278
 279         str = cmd_line;
 280
 281         j = 0;                  /* See close_handles */
 282
 283         if (!load_addr || !load_size)
 284                 return EFI_INVALID_PARAMETER;
 285
 286         *load_addr = 0;
 287         *load_size = 0;
 288
 289         if (!str || !*str)
 290                 return EFI_SUCCESS;
 291
 292         for (nr_files = 0; *str; nr_files++) {
 293                 str = strstr(str, option_string);
 294                 if (!str)
 295                         break;
 296
 297                 str += strlen(option_string);
 298
 299                 /* Skip any leading slashes */
 300                 while (*str == '/' || *str == '\\')
 301                         str++;
 302
 303                 while (*str && *str != ' ' && *str != '\n')
 304                         str++;
 305         }
 306
 307         if (!nr_files)
 308                 return EFI_SUCCESS;
 309
 310         status = efi_early->call(efi_early->allocate_pool, EFI_LOADER_DATA,
 311                                  nr_files * sizeof(*files), (void **)&files);
 312         if (status != EFI_SUCCESS) {
 313                 efi_printk(sys_table_arg, "Failed to alloc mem for file handle list\n");
 314                 goto fail;
 315         }
 316
 317         str = cmd_line;
 318         for (i = 0; i < nr_files; i++) {
 319                 struct file_info *file;
 320                 efi_char16_t filename_16[256];
 321                 efi_char16_t *p;
 322
 323                 str = strstr(str, option_string);
 324                 if (!str)
 325                         break;
 326
 327                 str += strlen(option_string);
 328
 329                 file = &files[i];
 330                 p = filename_16;
 331
 332                 /* Skip any leading slashes */
 333                 while (*str == '/' || *str == '\\')
 334                         str++;
 335
 336                 while (*str && *str != ' ' && *str != '\n') {
 337                         if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
 338                                 break;
 339
 340                         if (*str == '/') {
 341                                 *p++ = '\\';
 342                                 str++;
 343                         } else {
 344                                 *p++ = *str++;
 345                         }
 346                 }
 347
 348                 *p = '\0';
 349
 350                 /* Only open the volume once. */
 351                 if (!i) {
 352                         status = efi_open_volume(sys_table_arg, image,
 353                                                  (void **)&fh);
 354                         if (status != EFI_SUCCESS)
 355                                 goto free_files;
 356                 }
 357
 358                 status = efi_file_size(sys_table_arg, fh, filename_16,
 359                                        (void **)&file->handle, &file->size);
 360                 if (status != EFI_SUCCESS)
 361                         goto close_handles;
 362
 363                 file_size_total += file->size;
 364         }
 365
 366         if (file_size_total) {
 367                 unsigned long addr;
 368
 369                 /*
 370                  * Multiple files need to be at consecutive addresses in memory,
 371                  * so allocate enough memory for all the files.  This is used
 372                  * for loading multiple files.
 373                  */
 374                 status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
 375                                     &file_addr, max_addr);
 376                 if (status != EFI_SUCCESS) {
 377                         efi_printk(sys_table_arg, "Failed to alloc highmem for files\n");
 378                         goto close_handles;
 379                 }
 380
 381                 /* We've run out of free low memory. */
 382                 if (file_addr > max_addr) {
 383                         efi_printk(sys_table_arg, "We've run out of free low memory\n");
 384                         status = EFI_INVALID_PARAMETER;
 385                         goto free_file_total;
 386                 }
 387
 388                 addr = file_addr;
 389                 for (j = 0; j < nr_files; j++) {
 390                         unsigned long size;
 391
 392                         size = files[j].size;
 393                         while (size) {
 394                                 unsigned long chunksize;
 395                                 if (size > EFI_READ_CHUNK_SIZE)
 396                                         chunksize = EFI_READ_CHUNK_SIZE;
 397                                 else
 398                                         chunksize = size;
 399
 400                                 status = efi_file_read(fh, files[j].handle,
 401                                                        &chunksize,
 402                                                        (void *)addr);
 403                                 if (status != EFI_SUCCESS) {
 404                                         efi_printk(sys_table_arg, "Failed to read file\n");
 405                                         goto free_file_total;
 406                                 }
 407                                 addr += chunksize;
 408                                 size -= chunksize;
 409                         }
 410
 411                         efi_file_close(fh, files[j].handle);
 412                 }
 413
 414         }
 415
 416         efi_early->call(efi_early->free_pool, files);
 417
 418         *load_addr = file_addr;
 419         *load_size = file_size_total;
 420
 421         return status;
 422
 423 free_file_total:
 424         efi_free(sys_table_arg, file_size_total, file_addr);
 425
 426 close_handles:
 427         for (k = j; k < i; k++)
 428                 efi_file_close(fh, files[k].handle);
 429 free_files:
 430         efi_early->call(efi_early->free_pool, files);
 431 fail:
 432         *load_addr = 0;
 433         *load_size = 0;
 434
 435         return status;
 436 }
 437 /*
 438  * Relocate a kernel image, either compressed or uncompressed.
 439  * In the ARM64 case, all kernel images are currently
 440  * uncompressed, and as such when we relocate it we need to
 441  * allocate additional space for the BSS segment. Any low
 442  * memory that this function should avoid needs to be
 443  * unavailable in the EFI memory map, as if the preferred
 444  * address is not available the lowest available address will
 445  * be used.
 446  */
 447 static efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 448                                         unsigned long *image_addr,
 449                                         unsigned long image_size,
 450                                         unsigned long alloc_size,
 451                                         unsigned long preferred_addr,
 452                                         unsigned long alignment)
 453 {
 454         unsigned long cur_image_addr;
 455         unsigned long new_addr = 0;
 456         efi_status_t status;
 457         unsigned long nr_pages;
 458         efi_physical_addr_t efi_addr = preferred_addr;
 459
 460         if (!image_addr || !image_size || !alloc_size)
 461                 return EFI_INVALID_PARAMETER;
 462         if (alloc_size < image_size)
 463                 return EFI_INVALID_PARAMETER;
 464
 465         cur_image_addr = *image_addr;
 466
 467         /*
 468          * The EFI firmware loader could have placed the kernel image
 469          * anywhere in memory, but the kernel has restrictions on the
 470          * max physical address it can run at.  Some architectures
 471          * also have a prefered address, so first try to relocate
 472          * to the preferred address.  If that fails, allocate as low
 473          * as possible while respecting the required alignment.
 474          */
 475         nr_pages = round_up(alloc_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 476         status = efi_early->call(efi_early->allocate_pages,
 477                                  EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 478                                  nr_pages, &efi_addr);
 479         new_addr = efi_addr;
 480         /*
 481          * If preferred address allocation failed allocate as low as
 482          * possible.
 483          */
 484         if (status != EFI_SUCCESS) {
 485                 status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
 486                                        &new_addr);
 487         }
 488         if (status != EFI_SUCCESS) {
 489                 efi_printk(sys_table_arg, "ERROR: Failed to allocate usable memory for kernel.\n");
 490                 return status;
 491         }
 492
 493         /*
 494          * We know source/dest won't overlap since both memory ranges
 495          * have been allocated by UEFI, so we can safely use memcpy.
 496          */
 497         memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
 498
 499         /* Return the new address of the relocated image. */
 500         *image_addr = new_addr;
 501
 502         return status;
 503 }
 504
 505 /*
 506  * Convert the unicode UEFI command line to ASCII to pass to kernel.
 507  * Size of memory allocated return in *cmd_line_len.
 508  * Returns NULL on error.
 509  */
 510 static char *efi_convert_cmdline_to_ascii(efi_system_table_t *sys_table_arg,
 511                                       efi_loaded_image_t *image,
 512                                       int *cmd_line_len)
 513 {
 514         u16 *s2;
 515         u8 *s1 = NULL;
 516         unsigned long cmdline_addr = 0;
 517         int load_options_size = image->load_options_size / 2; /* ASCII */
 518         void *options = image->load_options;
 519         int options_size = 0;
 520         efi_status_t status;
 521         int i;
 522         u16 zero = 0;
 523
 524         if (options) {
 525                 s2 = options;
 526                 while (*s2 && *s2 != '\n' && options_size < load_options_size) {
 527                         s2++;
 528                         options_size++;
 529                 }
 530         }
 531
 532         if (options_size == 0) {
 533                 /* No command line options, so return empty string*/
 534                 options_size = 1;
 535                 options = &zero;
 536         }
 537
 538         options_size++;  /* NUL termination */
 539 #ifdef CONFIG_ARM
 540         /*
 541          * For ARM, allocate at a high address to avoid reserved
 542          * regions at low addresses that we don't know the specfics of
 543          * at the time we are processing the command line.
 544          */
 545         status = efi_high_alloc(sys_table_arg, options_size, 0,
 546                             &cmdline_addr, 0xfffff000);
 547 #else
 548         status = efi_low_alloc(sys_table_arg, options_size, 0,
 549                             &cmdline_addr);
 550 #endif
 551         if (status != EFI_SUCCESS)
 552                 return NULL;
 553
 554         s1 = (u8 *)cmdline_addr;
 555         s2 = (u16 *)options;
 556
 557         for (i = 0; i < options_size - 1; i++)
 558                 *s1++ = *s2++;
 559
 560         *s1 = '\0';
 561
 562         *cmd_line_len = options_size;
 563         return (char *)cmdline_addr;
 564 }