disk/part_efi.c

   1 /*
   2  * Copyright (C) 2008 RuggedCom, Inc.
   3  * Richard Retanubun <RichardRetanubun@RuggedCom.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Problems with CONFIG_SYS_64BIT_LBA:
  10  *
  11  * struct disk_partition.start in include/part.h is sized as ulong.
  12  * When CONFIG_SYS_64BIT_LBA is activated, lbaint_t changes from ulong to uint64_t.
  13  * For now, it is cast back to ulong at assignment.
  14  *
  15  * This limits the maximum size of addressable storage to < 2 Terra Bytes
  16  */
  17 #include <asm/unaligned.h>
  18 #include <common.h>
  19 #include <command.h>
  20 #include <ide.h>
  21 #include <malloc.h>
  22 #include <part_efi.h>
  23 #include <linux/ctype.h>
  24
  25 DECLARE_GLOBAL_DATA_PTR;
  26
  27 #ifdef HAVE_BLOCK_DEVICE
  28 /**
  29  * efi_crc32() - EFI version of crc32 function
  30  * @buf: buffer to calculate crc32 of
  31  * @len - length of buf
  32  *
  33  * Description: Returns EFI-style CRC32 value for @buf
  34  */
  35 static inline u32 efi_crc32(const void *buf, u32 len)
  36 {
  37         return crc32(0, buf, len);
  38 }
  39
  40 /*
  41  * Private function prototypes
  42  */
  43
  44 static int pmbr_part_valid(struct partition *part);
  45 static int is_pmbr_valid(legacy_mbr * mbr);
  46 static int is_gpt_valid(block_dev_desc_t * dev_desc, unsigned long long lba,
  47                                 gpt_header * pgpt_head, gpt_entry ** pgpt_pte);
  48 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
  49                                 gpt_header * pgpt_head);
  50 static int is_pte_valid(gpt_entry * pte);
  51
  52 static char *print_efiname(gpt_entry *pte)
  53 {
  54         static char name[PARTNAME_SZ + 1];
  55         int i;
  56         for (i = 0; i < PARTNAME_SZ; i++) {
  57                 u8 c;
  58                 c = pte->partition_name[i] & 0xff;
  59                 c = (c && !isprint(c)) ? '.' : c;
  60                 name[i] = c;
  61         }
  62         name[PARTNAME_SZ] = 0;
  63         return name;
  64 }
  65
  66 static efi_guid_t system_guid = PARTITION_SYSTEM_GUID;
  67
  68 static inline int is_bootable(gpt_entry *p)
  69 {
  70         return p->attributes.fields.legacy_bios_bootable ||
  71                 !memcmp(&(p->partition_type_guid), &system_guid,
  72                         sizeof(efi_guid_t));
  73 }
  74
  75 #ifdef CONFIG_EFI_PARTITION
  76 /*
  77  * Public Functions (include/part.h)
  78  */
  79
  80 void print_part_efi(block_dev_desc_t * dev_desc)
  81 {
  82         ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
  83         gpt_entry *gpt_pte = NULL;
  84         int i = 0;
  85         char uuid[37];
  86         unsigned char *uuid_bin;
  87
  88         if (!dev_desc) {
  89                 printf("%s: Invalid Argument(s)\n", __func__);
  90                 return;
  91         }
  92         /* This function validates AND fills in the GPT header and PTE */
  93         if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
  94                          gpt_head, &gpt_pte) != 1) {
  95                 printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
  96                 return;
  97         }
  98
  99         debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
 100
 101         printf("Part\tStart LBA\tEnd LBA\t\tName\n");
 102         printf("\tAttributes\n");
 103         printf("\tType UUID\n");
 104         printf("\tPartition UUID\n");
 105
 106         for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
 107                 /* Stop at the first non valid PTE */
 108                 if (!is_pte_valid(&gpt_pte[i]))
 109                         break;
 110
 111                 printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
 112                         le64_to_cpu(gpt_pte[i].starting_lba),
 113                         le64_to_cpu(gpt_pte[i].ending_lba),
 114                         print_efiname(&gpt_pte[i]));
 115                 printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
 116                 uuid_bin = (unsigned char *)gpt_pte[i].partition_type_guid.b;
 117                 uuid_bin_to_str(uuid_bin, uuid);
 118                 printf("\ttype:\t%s\n", uuid);
 119                 uuid_bin = (unsigned char *)gpt_pte[i].unique_partition_guid.b;
 120                 uuid_bin_to_str(uuid_bin, uuid);
 121                 printf("\tuuid:\t%s\n", uuid);
 122         }
 123
 124         /* Remember to free pte */
 125         free(gpt_pte);
 126         return;
 127 }
 128
 129 int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
 130                                 disk_partition_t * info)
 131 {
 132         ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
 133         gpt_entry *gpt_pte = NULL;
 134
 135         /* "part" argument must be at least 1 */
 136         if (!dev_desc || !info || part < 1) {
 137                 printf("%s: Invalid Argument(s)\n", __func__);
 138                 return -1;
 139         }
 140
 141         /* This function validates AND fills in the GPT header and PTE */
 142         if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
 143                         gpt_head, &gpt_pte) != 1) {
 144                 printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
 145                 return -1;
 146         }
 147
 148         if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
 149             !is_pte_valid(&gpt_pte[part - 1])) {
 150                 debug("%s: *** ERROR: Invalid partition number %d ***\n",
 151                         __func__, part);
 152                 free(gpt_pte);
 153                 return -1;
 154         }
 155
 156         /* The ulong casting limits the maximum disk size to 2 TB */
 157         info->start = (u64)le64_to_cpu(gpt_pte[part - 1].starting_lba);
 158         /* The ending LBA is inclusive, to calculate size, add 1 to it */
 159         info->size = ((u64)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1)
 160                      - info->start;
 161         info->blksz = dev_desc->blksz;
 162
 163         sprintf((char *)info->name, "%s",
 164                         print_efiname(&gpt_pte[part - 1]));
 165         sprintf((char *)info->type, "U-Boot");
 166         info->bootable = is_bootable(&gpt_pte[part - 1]);
 167 #ifdef CONFIG_PARTITION_UUIDS
 168         uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid);
 169 #endif
 170
 171         debug("%s: start 0x" LBAF ", size 0x" LBAF ", name %s", __func__,
 172               info->start, info->size, info->name);
 173
 174         /* Remember to free pte */
 175         free(gpt_pte);
 176         return 0;
 177 }
 178
 179 int test_part_efi(block_dev_desc_t * dev_desc)
 180 {
 181         ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);
 182
 183         /* Read legacy MBR from block 0 and validate it */
 184         if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)legacymbr) != 1)
 185                 || (is_pmbr_valid(legacymbr) != 1)) {
 186                 return -1;
 187         }
 188         return 0;
 189 }
 190
 191 /**
 192  * set_protective_mbr(): Set the EFI protective MBR
 193  * @param dev_desc - block device descriptor
 194  *
 195  * @return - zero on success, otherwise error
 196  */
 197 static int set_protective_mbr(block_dev_desc_t *dev_desc)
 198 {
 199         /* Setup the Protective MBR */
 200         ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, p_mbr, 1);
 201         memset(p_mbr, 0, sizeof(*p_mbr));
 202
 203         if (p_mbr == NULL) {
 204                 printf("%s: calloc failed!\n", __func__);
 205                 return -1;
 206         }
 207         /* Append signature */
 208         p_mbr->signature = MSDOS_MBR_SIGNATURE;
 209         p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
 210         p_mbr->partition_record[0].start_sect = 1;
 211         p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
 212
 213         /* Write MBR sector to the MMC device */
 214         if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
 215                 printf("** Can't write to device %d **\n",
 216                         dev_desc->dev);
 217                 return -1;
 218         }
 219
 220         return 0;
 221 }
 222
 223 int write_gpt_table(block_dev_desc_t *dev_desc,
 224                 gpt_header *gpt_h, gpt_entry *gpt_e)
 225 {
 226         const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
 227                                            * sizeof(gpt_entry)), dev_desc);
 228         u32 calc_crc32;
 229         u64 val;
 230
 231         debug("max lba: %x\n", (u32) dev_desc->lba);
 232         /* Setup the Protective MBR */
 233         if (set_protective_mbr(dev_desc) < 0)
 234                 goto err;
 235
 236         /* Generate CRC for the Primary GPT Header */
 237         calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
 238                               le32_to_cpu(gpt_h->num_partition_entries) *
 239                               le32_to_cpu(gpt_h->sizeof_partition_entry));
 240         gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
 241
 242         calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
 243                               le32_to_cpu(gpt_h->header_size));
 244         gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
 245
 246         /* Write the First GPT to the block right after the Legacy MBR */
 247         if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
 248                 goto err;
 249
 250         if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_cnt, gpt_e)
 251             != pte_blk_cnt)
 252                 goto err;
 253
 254         /* recalculate the values for the Second GPT Header */
 255         val = le64_to_cpu(gpt_h->my_lba);
 256         gpt_h->my_lba = gpt_h->alternate_lba;
 257         gpt_h->alternate_lba = cpu_to_le64(val);
 258         gpt_h->header_crc32 = 0;
 259
 260         calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
 261                               le32_to_cpu(gpt_h->header_size));
 262         gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
 263
 264         if (dev_desc->block_write(dev_desc->dev,
 265                                   le32_to_cpu(gpt_h->last_usable_lba + 1),
 266                                   pte_blk_cnt, gpt_e) != pte_blk_cnt)
 267                 goto err;
 268
 269         if (dev_desc->block_write(dev_desc->dev,
 270                                   le32_to_cpu(gpt_h->my_lba), 1, gpt_h) != 1)
 271                 goto err;
 272
 273         debug("GPT successfully written to block device!\n");
 274         return 0;
 275
 276  err:
 277         printf("** Can't write to device %d **\n", dev_desc->dev);
 278         return -1;
 279 }
 280
 281 int gpt_fill_pte(gpt_header *gpt_h, gpt_entry *gpt_e,
 282                 disk_partition_t *partitions, int parts)
 283 {
 284         u32 offset = (u32)le32_to_cpu(gpt_h->first_usable_lba);
 285         ulong start;
 286         int i, k;
 287         size_t efiname_len, dosname_len;
 288 #ifdef CONFIG_PARTITION_UUIDS
 289         char *str_uuid;
 290         unsigned char *bin_uuid;
 291 #endif
 292
 293         for (i = 0; i < parts; i++) {
 294                 /* partition starting lba */
 295                 start = partitions[i].start;
 296                 if (start && (start < offset)) {
 297                         printf("Partition overlap\n");
 298                         return -1;
 299                 }
 300                 if (start) {
 301                         gpt_e[i].starting_lba = cpu_to_le64(start);
 302                         offset = start + partitions[i].size;
 303                 } else {
 304                         gpt_e[i].starting_lba = cpu_to_le64(offset);
 305                         offset += partitions[i].size;
 306                 }
 307                 if (offset >= gpt_h->last_usable_lba) {
 308                         printf("Partitions layout exceds disk size\n");
 309                         return -1;
 310                 }
 311                 /* partition ending lba */
 312                 if ((i == parts - 1) && (partitions[i].size == 0))
 313                         /* extend the last partition to maximuim */
 314                         gpt_e[i].ending_lba = gpt_h->last_usable_lba;
 315                 else
 316                         gpt_e[i].ending_lba = cpu_to_le64(offset - 1);
 317
 318                 /* partition type GUID */
 319                 memcpy(gpt_e[i].partition_type_guid.b,
 320                         &PARTITION_BASIC_DATA_GUID, 16);
 321
 322 #ifdef CONFIG_PARTITION_UUIDS
 323                 str_uuid = partitions[i].uuid;
 324                 bin_uuid = gpt_e[i].unique_partition_guid.b;
 325
 326                 if (uuid_str_to_bin(str_uuid, bin_uuid)) {
 327                         printf("Partition no. %d: invalid guid: %s\n",
 328                                 i, str_uuid);
 329                         return -1;
 330                 }
 331 #endif
 332
 333                 /* partition attributes */
 334                 memset(&gpt_e[i].attributes, 0,
 335                        sizeof(gpt_entry_attributes));
 336
 337                 /* partition name */
 338                 efiname_len = sizeof(gpt_e[i].partition_name)
 339                         / sizeof(efi_char16_t);
 340                 dosname_len = sizeof(partitions[i].name);
 341
 342                 memset(gpt_e[i].partition_name, 0,
 343                        sizeof(gpt_e[i].partition_name));
 344
 345                 for (k = 0; k < min(dosname_len, efiname_len); k++)
 346                         gpt_e[i].partition_name[k] =
 347                                 (efi_char16_t)(partitions[i].name[k]);
 348
 349                 debug("%s: name: %s offset[%d]: 0x%x size[%d]: 0x" LBAF "\n",
 350                       __func__, partitions[i].name, i,
 351                       offset, i, partitions[i].size);
 352         }
 353
 354         return 0;
 355 }
 356
 357 int gpt_fill_header(block_dev_desc_t *dev_desc, gpt_header *gpt_h,
 358                 char *str_guid, int parts_count)
 359 {
 360         gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
 361         gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
 362         gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
 363         gpt_h->my_lba = cpu_to_le64(1);
 364         gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
 365         gpt_h->first_usable_lba = cpu_to_le64(34);
 366         gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
 367         gpt_h->partition_entry_lba = cpu_to_le64(2);
 368         gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
 369         gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
 370         gpt_h->header_crc32 = 0;
 371         gpt_h->partition_entry_array_crc32 = 0;
 372
 373         if (uuid_str_to_bin(str_guid, gpt_h->disk_guid.b))
 374                 return -1;
 375
 376         return 0;
 377 }
 378
 379 int gpt_restore(block_dev_desc_t *dev_desc, char *str_disk_guid,
 380                 disk_partition_t *partitions, int parts_count)
 381 {
 382         int ret;
 383
 384         gpt_header *gpt_h = calloc(1, PAD_TO_BLOCKSIZE(sizeof(gpt_header),
 385                                                        dev_desc));
 386         gpt_entry *gpt_e;
 387
 388         if (gpt_h == NULL) {
 389                 printf("%s: calloc failed!\n", __func__);
 390                 return -1;
 391         }
 392
 393         gpt_e = calloc(1, PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS
 394                                                * sizeof(gpt_entry),
 395                                                dev_desc));
 396         if (gpt_e == NULL) {
 397                 printf("%s: calloc failed!\n", __func__);
 398                 free(gpt_h);
 399                 return -1;
 400         }
 401
 402         /* Generate Primary GPT header (LBA1) */
 403         ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
 404         if (ret)
 405                 goto err;
 406
 407         /* Generate partition entries */
 408         ret = gpt_fill_pte(gpt_h, gpt_e, partitions, parts_count);
 409         if (ret)
 410                 goto err;
 411
 412         /* Write GPT partition table */
 413         ret = write_gpt_table(dev_desc, gpt_h, gpt_e);
 414
 415 err:
 416         free(gpt_e);
 417         free(gpt_h);
 418         return ret;
 419 }
 420 #endif
 421
 422 /*
 423  * Private functions
 424  */
 425 /*
 426  * pmbr_part_valid(): Check for EFI partition signature
 427  *
 428  * Returns: 1 if EFI GPT partition type is found.
 429  */
 430 static int pmbr_part_valid(struct partition *part)
 431 {
 432         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
 433                 get_unaligned_le32(&part->start_sect) == 1UL) {
 434                 return 1;
 435         }
 436
 437         return 0;
 438 }
 439
 440 /*
 441  * is_pmbr_valid(): test Protective MBR for validity
 442  *
 443  * Returns: 1 if PMBR is valid, 0 otherwise.
 444  * Validity depends on two things:
 445  *  1) MSDOS signature is in the last two bytes of the MBR
 446  *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
 447  */
 448 static int is_pmbr_valid(legacy_mbr * mbr)
 449 {
 450         int i = 0;
 451
 452         if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
 453                 return 0;
 454
 455         for (i = 0; i < 4; i++) {
 456                 if (pmbr_part_valid(&mbr->partition_record[i])) {
 457                         return 1;
 458                 }
 459         }
 460         return 0;
 461 }
 462
 463 /**
 464  * is_gpt_valid() - tests one GPT header and PTEs for validity
 465  *
 466  * lba is the logical block address of the GPT header to test
 467  * gpt is a GPT header ptr, filled on return.
 468  * ptes is a PTEs ptr, filled on return.
 469  *
 470  * Description: returns 1 if valid,  0 on error.
 471  * If valid, returns pointers to PTEs.
 472  */
 473 static int is_gpt_valid(block_dev_desc_t * dev_desc, unsigned long long lba,
 474                         gpt_header * pgpt_head, gpt_entry ** pgpt_pte)
 475 {
 476         u32 crc32_backup = 0;
 477         u32 calc_crc32;
 478         unsigned long long lastlba;
 479
 480         if (!dev_desc || !pgpt_head) {
 481                 printf("%s: Invalid Argument(s)\n", __func__);
 482                 return 0;
 483         }
 484
 485         /* Read GPT Header from device */
 486         if (dev_desc->block_read(dev_desc->dev, lba, 1, pgpt_head) != 1) {
 487                 printf("*** ERROR: Can't read GPT header ***\n");
 488                 return 0;
 489         }
 490
 491         /* Check the GPT header signature */
 492         if (le64_to_cpu(pgpt_head->signature) != GPT_HEADER_SIGNATURE) {
 493                 printf("GUID Partition Table Header signature is wrong:"
 494                         "0x%llX != 0x%llX\n",
 495                         le64_to_cpu(pgpt_head->signature),
 496                         GPT_HEADER_SIGNATURE);
 497                 return 0;
 498         }
 499
 500         /* Check the GUID Partition Table CRC */
 501         memcpy(&crc32_backup, &pgpt_head->header_crc32, sizeof(crc32_backup));
 502         memset(&pgpt_head->header_crc32, 0, sizeof(pgpt_head->header_crc32));
 503
 504         calc_crc32 = efi_crc32((const unsigned char *)pgpt_head,
 505                 le32_to_cpu(pgpt_head->header_size));
 506
 507         memcpy(&pgpt_head->header_crc32, &crc32_backup, sizeof(crc32_backup));
 508
 509         if (calc_crc32 != le32_to_cpu(crc32_backup)) {
 510                 printf("GUID Partition Table Header CRC is wrong:"
 511                         "0x%x != 0x%x\n",
 512                        le32_to_cpu(crc32_backup), calc_crc32);
 513                 return 0;
 514         }
 515
 516         /* Check that the my_lba entry points to the LBA that contains the GPT */
 517         if (le64_to_cpu(pgpt_head->my_lba) != lba) {
 518                 printf("GPT: my_lba incorrect: %llX != %llX\n",
 519                         le64_to_cpu(pgpt_head->my_lba),
 520                         lba);
 521                 return 0;
 522         }
 523
 524         /* Check the first_usable_lba and last_usable_lba are within the disk. */
 525         lastlba = (unsigned long long)dev_desc->lba;
 526         if (le64_to_cpu(pgpt_head->first_usable_lba) > lastlba) {
 527                 printf("GPT: first_usable_lba incorrect: %llX > %llX\n",
 528                         le64_to_cpu(pgpt_head->first_usable_lba), lastlba);
 529                 return 0;
 530         }
 531         if (le64_to_cpu(pgpt_head->last_usable_lba) > lastlba) {
 532                 printf("GPT: last_usable_lba incorrect: %llX > %llX\n",
 533                         (u64) le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
 534                 return 0;
 535         }
 536
 537         debug("GPT: first_usable_lba: %llX last_usable_lba %llX last lba %llX\n",
 538                 le64_to_cpu(pgpt_head->first_usable_lba),
 539                 le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
 540
 541         /* Read and allocate Partition Table Entries */
 542         *pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
 543         if (*pgpt_pte == NULL) {
 544                 printf("GPT: Failed to allocate memory for PTE\n");
 545                 return 0;
 546         }
 547
 548         /* Check the GUID Partition Table Entry Array CRC */
 549         calc_crc32 = efi_crc32((const unsigned char *)*pgpt_pte,
 550                 le32_to_cpu(pgpt_head->num_partition_entries) *
 551                 le32_to_cpu(pgpt_head->sizeof_partition_entry));
 552
 553         if (calc_crc32 != le32_to_cpu(pgpt_head->partition_entry_array_crc32)) {
 554                 printf("GUID Partition Table Entry Array CRC is wrong:"
 555                         "0x%x != 0x%x\n",
 556                         le32_to_cpu(pgpt_head->partition_entry_array_crc32),
 557                         calc_crc32);
 558
 559                 free(*pgpt_pte);
 560                 return 0;
 561         }
 562
 563         /* We're done, all's well */
 564         return 1;
 565 }
 566
 567 /**
 568  * alloc_read_gpt_entries(): reads partition entries from disk
 569  * @dev_desc
 570  * @gpt - GPT header
 571  *
 572  * Description: Returns ptes on success,  NULL on error.
 573  * Allocates space for PTEs based on information found in @gpt.
 574  * Notes: remember to free pte when you're done!
 575  */
 576 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
 577                                          gpt_header * pgpt_head)
 578 {
 579         size_t count = 0, blk_cnt;
 580         gpt_entry *pte = NULL;
 581
 582         if (!dev_desc || !pgpt_head) {
 583                 printf("%s: Invalid Argument(s)\n", __func__);
 584                 return NULL;
 585         }
 586
 587         count = le32_to_cpu(pgpt_head->num_partition_entries) *
 588                 le32_to_cpu(pgpt_head->sizeof_partition_entry);
 589
 590         debug("%s: count = %u * %u = %zu\n", __func__,
 591               (u32) le32_to_cpu(pgpt_head->num_partition_entries),
 592               (u32) le32_to_cpu(pgpt_head->sizeof_partition_entry), count);
 593
 594         /* Allocate memory for PTE, remember to FREE */
 595         if (count != 0) {
 596                 pte = memalign(ARCH_DMA_MINALIGN,
 597                                PAD_TO_BLOCKSIZE(count, dev_desc));
 598         }
 599
 600         if (count == 0 || pte == NULL) {
 601                 printf("%s: ERROR: Can't allocate 0x%zX "
 602                        "bytes for GPT Entries\n",
 603                         __func__, count);
 604                 return NULL;
 605         }
 606
 607         /* Read GPT Entries from device */
 608         blk_cnt = BLOCK_CNT(count, dev_desc);
 609         if (dev_desc->block_read (dev_desc->dev,
 610                 le64_to_cpu(pgpt_head->partition_entry_lba),
 611                 (lbaint_t) (blk_cnt), pte)
 612                 != blk_cnt) {
 613
 614                 printf("*** ERROR: Can't read GPT Entries ***\n");
 615                 free(pte);
 616                 return NULL;
 617         }
 618         return pte;
 619 }
 620
 621 /**
 622  * is_pte_valid(): validates a single Partition Table Entry
 623  * @gpt_entry - Pointer to a single Partition Table Entry
 624  *
 625  * Description: returns 1 if valid,  0 on error.
 626  */
 627 static int is_pte_valid(gpt_entry * pte)
 628 {
 629         efi_guid_t unused_guid;
 630
 631         if (!pte) {
 632                 printf("%s: Invalid Argument(s)\n", __func__);
 633                 return 0;
 634         }
 635
 636         /* Only one validation for now:
 637          * The GUID Partition Type != Unused Entry (ALL-ZERO)
 638          */
 639         memset(unused_guid.b, 0, sizeof(unused_guid.b));
 640
 641         if (memcmp(pte->partition_type_guid.b, unused_guid.b,
 642                 sizeof(unused_guid.b)) == 0) {
 643
 644                 debug("%s: Found an unused PTE GUID at 0x%08X\n", __func__,
 645                       (unsigned int)(uintptr_t)pte);
 646
 647                 return 0;
 648         } else {
 649                 return 1;
 650         }
 651 }
 652 #endif