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