fs/partitions/efi.c

   1 /************************************************************
   2  * EFI GUID Partition Table handling
   3  * Per Intel EFI Specification v1.02
   4  * http://developer.intel.com/technology/efi/efi.htm
   5  * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
   6  *   Copyright 2000,2001,2002,2004 Dell Inc.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *
  23  * TODO:
  24  *
  25  * Changelog:
  26  * Mon Nov 09 2004 Matt Domsch <Matt_Domsch@dell.com>
  27  * - test for valid PMBR and valid PGPT before ever reading
  28  *   AGPT, allow override with 'gpt' kernel command line option.
  29  * - check for first/last_usable_lba outside of size of disk
  30  *
  31  * Tue  Mar 26 2002 Matt Domsch <Matt_Domsch@dell.com>
  32  * - Ported to 2.5.7-pre1 and 2.5.7-dj2
  33  * - Applied patch to avoid fault in alternate header handling
  34  * - cleaned up find_valid_gpt
  35  * - On-disk structure and copy in memory is *always* LE now -
  36  *   swab fields as needed
  37  * - remove print_gpt_header()
  38  * - only use first max_p partition entries, to keep the kernel minor number
  39  *   and partition numbers tied.
  40  *
  41  * Mon  Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
  42  * - Removed __PRIPTR_PREFIX - not being used
  43  *
  44  * Mon  Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
  45  * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
  46  *
  47  * Thu Dec 6 2001 Matt Domsch <Matt_Domsch@dell.com>
  48  * - Added compare_gpts().
  49  * - moved le_efi_guid_to_cpus() back into this file.  GPT is the only
  50  *   thing that keeps EFI GUIDs on disk.
  51  * - Changed gpt structure names and members to be simpler and more Linux-like.
  52  *
  53  * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
  54  * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
  55  *
  56  * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
  57  * - Changed function comments to DocBook style per Andreas Dilger suggestion.
  58  *
  59  * Mon Oct 08 2001 Matt Domsch <Matt_Domsch@dell.com>
  60  * - Change read_lba() to use the page cache per Al Viro's work.
  61  * - print u64s properly on all architectures
  62  * - fixed debug_printk(), now Dprintk()
  63  *
  64  * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
  65  * - Style cleanups
  66  * - made most functions static
  67  * - Endianness addition
  68  * - remove test for second alternate header, as it's not per spec,
  69  *   and is unnecessary.  There's now a method to read/write the last
  70  *   sector of an odd-sized disk from user space.  No tools have ever
  71  *   been released which used this code, so it's effectively dead.
  72  * - Per Asit Mallick of Intel, added a test for a valid PMBR.
  73  * - Added kernel command line option 'gpt' to override valid PMBR test.
  74  *
  75  * Wed Jun  6 2001 Martin Wilck <Martin.Wilck@Fujitsu-Siemens.com>
  76  * - added devfs volume UUID support (/dev/volumes/uuids) for
  77  *   mounting file systems by the partition GUID.
  78  *
  79  * Tue Dec  5 2000 Matt Domsch <Matt_Domsch@dell.com>
  80  * - Moved crc32() to linux/lib, added efi_crc32().
  81  *
  82  * Thu Nov 30 2000 Matt Domsch <Matt_Domsch@dell.com>
  83  * - Replaced Intel's CRC32 function with an equivalent
  84  *   non-license-restricted version.
  85  *
  86  * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
  87  * - Fixed the last_lba() call to return the proper last block
  88  *
  89  * Thu Oct 12 2000 Matt Domsch <Matt_Domsch@dell.com>
  90  * - Thanks to Andries Brouwer for his debugging assistance.
  91  * - Code works, detects all the partitions.
  92  *
  93  ************************************************************/
  94 #include <linux/crc32.h>
  95 #include "check.h"
  96 #include "efi.h"
  97
  98 /* This allows a kernel command line option 'gpt' to override
  99  * the test for invalid PMBR.  Not __initdata because reloading
 100  * the partition tables happens after init too.
 101  */
 102 static int force_gpt;
 103 static int __init
 104 force_gpt_fn(char *str)
 105 {
 106         force_gpt = 1;
 107         return 1;
 108 }
 109 __setup("gpt", force_gpt_fn);
 110
 111
 112 /**
 113  * efi_crc32() - EFI version of crc32 function
 114  * @buf: buffer to calculate crc32 of
 115  * @len - length of buf
 116  *
 117  * Description: Returns EFI-style CRC32 value for @buf
 118  *
 119  * This function uses the little endian Ethernet polynomial
 120  * but seeds the function with ~0, and xor's with ~0 at the end.
 121  * Note, the EFI Specification, v1.02, has a reference to
 122  * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
 123  */
 124 static inline u32
 125 efi_crc32(const void *buf, unsigned long len)
 126 {
 127         return (crc32(~0L, buf, len) ^ ~0L);
 128 }
 129
 130 /**
 131  * last_lba(): return number of last logical block of device
 132  * @bdev: block device
 133  *
 134  * Description: Returns last LBA value on success, 0 on error.
 135  * This is stored (by sd and ide-geometry) in
 136  *  the part[0] entry for this disk, and is the number of
 137  *  physical sectors available on the disk.
 138  */
 139 static u64
 140 last_lba(struct block_device *bdev)
 141 {
 142         if (!bdev || !bdev->bd_inode)
 143                 return 0;
 144         return (bdev->bd_inode->i_size >> 9) - 1ULL;
 145 }
 146
 147 static inline int
 148 pmbr_part_valid(struct partition *part)
 149 {
 150         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
 151             le32_to_cpu(part->start_sect) == 1UL)
 152                 return 1;
 153         return 0;
 154 }
 155
 156 /**
 157  * is_pmbr_valid(): test Protective MBR for validity
 158  * @mbr: pointer to a legacy mbr structure
 159  *
 160  * Description: Returns 1 if PMBR is valid, 0 otherwise.
 161  * Validity depends on two things:
 162  *  1) MSDOS signature is in the last two bytes of the MBR
 163  *  2) One partition of type 0xEE is found
 164  */
 165 static int
 166 is_pmbr_valid(legacy_mbr *mbr)
 167 {
 168         int i;
 169         if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
 170                 return 0;
 171         for (i = 0; i < 4; i++)
 172                 if (pmbr_part_valid(&mbr->partition_record[i]))
 173                         return 1;
 174         return 0;
 175 }
 176
 177 /**
 178  * read_lba(): Read bytes from disk, starting at given LBA
 179  * @bdev
 180  * @lba
 181  * @buffer
 182  * @size_t
 183  *
 184  * Description:  Reads @count bytes from @bdev into @buffer.
 185  * Returns number of bytes read on success, 0 on error.
 186  */
 187 static size_t
 188 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
 189 {
 190         size_t totalreadcount = 0;
 191
 192         if (!bdev || !buffer || lba > last_lba(bdev))
 193                 return 0;
 194
 195         while (count) {
 196                 int copied = 512;
 197                 Sector sect;
 198                 unsigned char *data = read_dev_sector(bdev, lba++, &sect);
 199                 if (!data)
 200                         break;
 201                 if (copied > count)
 202                         copied = count;
 203                 memcpy(buffer, data, copied);
 204                 put_dev_sector(sect);
 205                 buffer += copied;
 206                 totalreadcount +=copied;
 207                 count -= copied;
 208         }
 209         return totalreadcount;
 210 }
 211
 212 /**
 213  * alloc_read_gpt_entries(): reads partition entries from disk
 214  * @bdev
 215  * @gpt - GPT header
 216  *
 217  * Description: Returns ptes on success,  NULL on error.
 218  * Allocates space for PTEs based on information found in @gpt.
 219  * Notes: remember to free pte when you're done!
 220  */
 221 static gpt_entry *
 222 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
 223 {
 224         size_t count;
 225         gpt_entry *pte;
 226         if (!bdev || !gpt)
 227                 return NULL;
 228
 229         count = le32_to_cpu(gpt->num_partition_entries) *
 230                 le32_to_cpu(gpt->sizeof_partition_entry);
 231         if (!count)
 232                 return NULL;
 233         pte = kzalloc(count, GFP_KERNEL);
 234         if (!pte)
 235                 return NULL;
 236
 237         if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
 238                      (u8 *) pte,
 239                      count) < count) {
 240                 kfree(pte);
 241                 pte=NULL;
 242                 return NULL;
 243         }
 244         return pte;
 245 }
 246
 247 /**
 248  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 249  * @bdev
 250  * @lba is the Logical Block Address of the partition table
 251  *
 252  * Description: returns GPT header on success, NULL on error.   Allocates
 253  * and fills a GPT header starting at @ from @bdev.
 254  * Note: remember to free gpt when finished with it.
 255  */
 256 static gpt_header *
 257 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
 258 {
 259         gpt_header *gpt;
 260         if (!bdev)
 261                 return NULL;
 262
 263         gpt = kzalloc(sizeof (gpt_header), GFP_KERNEL);
 264         if (!gpt)
 265                 return NULL;
 266
 267         if (read_lba(bdev, lba, (u8 *) gpt,
 268                      sizeof (gpt_header)) < sizeof (gpt_header)) {
 269                 kfree(gpt);
 270                 gpt=NULL;
 271                 return NULL;
 272         }
 273
 274         return gpt;
 275 }
 276
 277 /**
 278  * is_gpt_valid() - tests one GPT header and PTEs for validity
 279  * @bdev
 280  * @lba is the logical block address of the GPT header to test
 281  * @gpt is a GPT header ptr, filled on return.
 282  * @ptes is a PTEs ptr, filled on return.
 283  *
 284  * Description: returns 1 if valid,  0 on error.
 285  * If valid, returns pointers to newly allocated GPT header and PTEs.
 286  */
 287 static int
 288 is_gpt_valid(struct block_device *bdev, u64 lba,
 289              gpt_header **gpt, gpt_entry **ptes)
 290 {
 291         u32 crc, origcrc;
 292         u64 lastlba;
 293
 294         if (!bdev || !gpt || !ptes)
 295                 return 0;
 296         if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
 297                 return 0;
 298
 299         /* Check the GUID Partition Table signature */
 300         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 301                 pr_debug("GUID Partition Table Header signature is wrong:"
 302                          "%lld != %lld\n",
 303                          (unsigned long long)le64_to_cpu((*gpt)->signature),
 304                          (unsigned long long)GPT_HEADER_SIGNATURE);
 305                 goto fail;
 306         }
 307
 308         /* Check the GUID Partition Table CRC */
 309         origcrc = le32_to_cpu((*gpt)->header_crc32);
 310         (*gpt)->header_crc32 = 0;
 311         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 312
 313         if (crc != origcrc) {
 314                 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
 315                          crc, origcrc);
 316                 goto fail;
 317         }
 318         (*gpt)->header_crc32 = cpu_to_le32(origcrc);
 319
 320         /* Check that the my_lba entry points to the LBA that contains
 321          * the GUID Partition Table */
 322         if (le64_to_cpu((*gpt)->my_lba) != lba) {
 323                 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
 324                          (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 325                          (unsigned long long)lba);
 326                 goto fail;
 327         }
 328
 329         /* Check the first_usable_lba and last_usable_lba are
 330          * within the disk.
 331          */
 332         lastlba = last_lba(bdev);
 333         if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 334                 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 335                          (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
 336                          (unsigned long long)lastlba);
 337                 goto fail;
 338         }
 339         if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
 340                 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
 341                          (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
 342                          (unsigned long long)lastlba);
 343                 goto fail;
 344         }
 345
 346         if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
 347                 goto fail;
 348
 349         /* Check the GUID Partition Entry Array CRC */
 350         crc = efi_crc32((const unsigned char *) (*ptes),
 351                         le32_to_cpu((*gpt)->num_partition_entries) *
 352                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 353
 354         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 355                 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
 356                 goto fail_ptes;
 357         }
 358
 359         /* We're done, all's well */
 360         return 1;
 361
 362  fail_ptes:
 363         kfree(*ptes);
 364         *ptes = NULL;
 365  fail:
 366         kfree(*gpt);
 367         *gpt = NULL;
 368         return 0;
 369 }
 370
 371 /**
 372  * is_pte_valid() - tests one PTE for validity
 373  * @pte is the pte to check
 374  * @lastlba is last lba of the disk
 375  *
 376  * Description: returns 1 if valid,  0 on error.
 377  */
 378 static inline int
 379 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
 380 {
 381         if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
 382             le64_to_cpu(pte->starting_lba) > lastlba         ||
 383             le64_to_cpu(pte->ending_lba)   > lastlba)
 384                 return 0;
 385         return 1;
 386 }
 387
 388 /**
 389  * compare_gpts() - Search disk for valid GPT headers and PTEs
 390  * @pgpt is the primary GPT header
 391  * @agpt is the alternate GPT header
 392  * @lastlba is the last LBA number
 393  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 394  * and prints warnings on discrepancies.
 395  *
 396  */
 397 static void
 398 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 399 {
 400         int error_found = 0;
 401         if (!pgpt || !agpt)
 402                 return;
 403         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 404                 printk(KERN_WARNING
 405                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 406                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 407                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 408                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 409                 error_found++;
 410         }
 411         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 412                 printk(KERN_WARNING
 413                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 414                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 415                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 416                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 417                 error_found++;
 418         }
 419         if (le64_to_cpu(pgpt->first_usable_lba) !=
 420             le64_to_cpu(agpt->first_usable_lba)) {
 421                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 422                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 423                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 424                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 425                 error_found++;
 426         }
 427         if (le64_to_cpu(pgpt->last_usable_lba) !=
 428             le64_to_cpu(agpt->last_usable_lba)) {
 429                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 430                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 431                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 432                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 433                 error_found++;
 434         }
 435         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 436                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 437                 error_found++;
 438         }
 439         if (le32_to_cpu(pgpt->num_partition_entries) !=
 440             le32_to_cpu(agpt->num_partition_entries)) {
 441                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 442                        "0x%x != 0x%x\n",
 443                        le32_to_cpu(pgpt->num_partition_entries),
 444                        le32_to_cpu(agpt->num_partition_entries));
 445                 error_found++;
 446         }
 447         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 448             le32_to_cpu(agpt->sizeof_partition_entry)) {
 449                 printk(KERN_WARNING
 450                        "GPT:sizeof_partition_entry values don't match: "
 451                        "0x%x != 0x%x\n",
 452                        le32_to_cpu(pgpt->sizeof_partition_entry),
 453                        le32_to_cpu(agpt->sizeof_partition_entry));
 454                 error_found++;
 455         }
 456         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 457             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 458                 printk(KERN_WARNING
 459                        "GPT:partition_entry_array_crc32 values don't match: "
 460                        "0x%x != 0x%x\n",
 461                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 462                        le32_to_cpu(agpt->partition_entry_array_crc32));
 463                 error_found++;
 464         }
 465         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 466                 printk(KERN_WARNING
 467                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 468                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 469                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 470                         (unsigned long long)lastlba);
 471                 error_found++;
 472         }
 473
 474         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 475                 printk(KERN_WARNING
 476                        "GPT:Alternate GPT header not at the end of the disk.\n");
 477                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 478                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 479                         (unsigned long long)lastlba);
 480                 error_found++;
 481         }
 482
 483         if (error_found)
 484                 printk(KERN_WARNING
 485                        "GPT: Use GNU Parted to correct GPT errors.\n");
 486         return;
 487 }
 488
 489 /**
 490  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 491  * @bdev
 492  * @gpt is a GPT header ptr, filled on return.
 493  * @ptes is a PTEs ptr, filled on return.
 494  * Description: Returns 1 if valid, 0 on error.
 495  * If valid, returns pointers to newly allocated GPT header and PTEs.
 496  * Validity depends on PMBR being valid (or being overridden by the
 497  * 'gpt' kernel command line option) and finding either the Primary
 498  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
 499  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
 500  * is not checked unless the 'gpt' kernel command line option is passed.
 501  * This protects against devices which misreport their size, and forces
 502  * the user to decide to use the Alternate GPT.
 503  */
 504 static int
 505 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
 506 {
 507         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 508         gpt_header *pgpt = NULL, *agpt = NULL;
 509         gpt_entry *pptes = NULL, *aptes = NULL;
 510         legacy_mbr *legacymbr;
 511         u64 lastlba;
 512         if (!bdev || !gpt || !ptes)
 513                 return 0;
 514
 515         lastlba = last_lba(bdev);
 516         if (!force_gpt) {
 517                 /* This will be added to the EFI Spec. per Intel after v1.02. */
 518                 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
 519                 if (legacymbr) {
 520                         read_lba(bdev, 0, (u8 *) legacymbr,
 521                                  sizeof (*legacymbr));
 522                         good_pmbr = is_pmbr_valid(legacymbr);
 523                         kfree(legacymbr);
 524                 }
 525                 if (!good_pmbr)
 526                         goto fail;
 527         }
 528
 529         good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
 530                                  &pgpt, &pptes);
 531         if (good_pgpt)
 532                 good_agpt = is_gpt_valid(bdev,
 533                                          le64_to_cpu(pgpt->alternate_lba),
 534                                          &agpt, &aptes);
 535         if (!good_agpt && force_gpt)
 536                 good_agpt = is_gpt_valid(bdev, lastlba,
 537                                          &agpt, &aptes);
 538
 539         /* The obviously unsuccessful case */
 540         if (!good_pgpt && !good_agpt)
 541                 goto fail;
 542
 543         compare_gpts(pgpt, agpt, lastlba);
 544
 545         /* The good cases */
 546         if (good_pgpt) {
 547                 *gpt  = pgpt;
 548                 *ptes = pptes;
 549                 kfree(agpt);
 550                 kfree(aptes);
 551                 if (!good_agpt) {
 552                         printk(KERN_WARNING
 553                                "Alternate GPT is invalid, "
 554                                "using primary GPT.\n");
 555                 }
 556                 return 1;
 557         }
 558         else if (good_agpt) {
 559                 *gpt  = agpt;
 560                 *ptes = aptes;
 561                 kfree(pgpt);
 562                 kfree(pptes);
 563                 printk(KERN_WARNING
 564                        "Primary GPT is invalid, using alternate GPT.\n");
 565                 return 1;
 566         }
 567
 568  fail:
 569         kfree(pgpt);
 570         kfree(agpt);
 571         kfree(pptes);
 572         kfree(aptes);
 573         *gpt = NULL;
 574         *ptes = NULL;
 575         return 0;
 576 }
 577
 578 /**
 579  * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 580  * @state
 581  * @bdev
 582  *
 583  * Description: called from check.c, if the disk contains GPT
 584  * partitions, sets up partition entries in the kernel.
 585  *
 586  * If the first block on the disk is a legacy MBR,
 587  * it will get handled by msdos_partition().
 588  * If it's a Protective MBR, we'll handle it here.
 589  *
 590  * We do not create a Linux partition for GPT, but
 591  * only for the actual data partitions.
 592  * Returns:
 593  * -1 if unable to read the partition table
 594  *  0 if this isn't our partition table
 595  *  1 if successful
 596  *
 597  */
 598 int
 599 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 600 {
 601         gpt_header *gpt = NULL;
 602         gpt_entry *ptes = NULL;
 603         u32 i;
 604
 605         if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
 606                 kfree(gpt);
 607                 kfree(ptes);
 608                 return 0;
 609         }
 610
 611         pr_debug("GUID Partition Table is valid!  Yea!\n");
 612
 613         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 614                 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
 615                         continue;
 616
 617                 put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
 618                                  (le64_to_cpu(ptes[i].ending_lba) -
 619                                   le64_to_cpu(ptes[i].starting_lba) +
 620                                   1ULL));
 621
 622                 /* If this is a RAID volume, tell md */
 623                 if (!efi_guidcmp(ptes[i].partition_type_guid,
 624                                  PARTITION_LINUX_RAID_GUID))
 625                         state->parts[i+1].flags = 1;
 626         }
 627         kfree(ptes);
 628         kfree(gpt);
 629         printk("\n");
 630         return 1;
 631 }