fs/partitions/efi.c

   1 /************************************************************
   2  * EFI GUID Partition Table handling
   3  *
   4  * http://www.uefi.org/specs/
   5  * http://www.intel.com/technology/efi/
   6  *
   7  * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
   8  *   Copyright 2000,2001,2002,2004 Dell Inc.
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  *
  25  * TODO:
  26  *
  27  * Changelog:
  28  * Mon Nov 09 2004 Matt Domsch <Matt_Domsch@dell.com>
  29  * - test for valid PMBR and valid PGPT before ever reading
  30  *   AGPT, allow override with 'gpt' kernel command line option.
  31  * - check for first/last_usable_lba outside of size of disk
  32  *
  33  * Tue  Mar 26 2002 Matt Domsch <Matt_Domsch@dell.com>
  34  * - Ported to 2.5.7-pre1 and 2.5.7-dj2
  35  * - Applied patch to avoid fault in alternate header handling
  36  * - cleaned up find_valid_gpt
  37  * - On-disk structure and copy in memory is *always* LE now -
  38  *   swab fields as needed
  39  * - remove print_gpt_header()
  40  * - only use first max_p partition entries, to keep the kernel minor number
  41  *   and partition numbers tied.
  42  *
  43  * Mon  Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
  44  * - Removed __PRIPTR_PREFIX - not being used
  45  *
  46  * Mon  Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
  47  * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
  48  *
  49  * Thu Dec 6 2001 Matt Domsch <Matt_Domsch@dell.com>
  50  * - Added compare_gpts().
  51  * - moved le_efi_guid_to_cpus() back into this file.  GPT is the only
  52  *   thing that keeps EFI GUIDs on disk.
  53  * - Changed gpt structure names and members to be simpler and more Linux-like.
  54  *
  55  * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
  56  * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
  57  *
  58  * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
  59  * - Changed function comments to DocBook style per Andreas Dilger suggestion.
  60  *
  61  * Mon Oct 08 2001 Matt Domsch <Matt_Domsch@dell.com>
  62  * - Change read_lba() to use the page cache per Al Viro's work.
  63  * - print u64s properly on all architectures
  64  * - fixed debug_printk(), now Dprintk()
  65  *
  66  * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
  67  * - Style cleanups
  68  * - made most functions static
  69  * - Endianness addition
  70  * - remove test for second alternate header, as it's not per spec,
  71  *   and is unnecessary.  There's now a method to read/write the last
  72  *   sector of an odd-sized disk from user space.  No tools have ever
  73  *   been released which used this code, so it's effectively dead.
  74  * - Per Asit Mallick of Intel, added a test for a valid PMBR.
  75  * - Added kernel command line option 'gpt' to override valid PMBR test.
  76  *
  77  * Wed Jun  6 2001 Martin Wilck <Martin.Wilck@Fujitsu-Siemens.com>
  78  * - added devfs volume UUID support (/dev/volumes/uuids) for
  79  *   mounting file systems by the partition GUID.
  80  *
  81  * Tue Dec  5 2000 Matt Domsch <Matt_Domsch@dell.com>
  82  * - Moved crc32() to linux/lib, added efi_crc32().
  83  *
  84  * Thu Nov 30 2000 Matt Domsch <Matt_Domsch@dell.com>
  85  * - Replaced Intel's CRC32 function with an equivalent
  86  *   non-license-restricted version.
  87  *
  88  * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
  89  * - Fixed the last_lba() call to return the proper last block
  90  *
  91  * Thu Oct 12 2000 Matt Domsch <Matt_Domsch@dell.com>
  92  * - Thanks to Andries Brouwer for his debugging assistance.
  93  * - Code works, detects all the partitions.
  94  *
  95  ************************************************************/
  96 #include <linux/crc32.h>
  97 #include <linux/math64.h>
  98 #include <linux/slab.h>
  99 #include "check.h"
 100 #include "efi.h"
 101
 102 /* This allows a kernel command line option 'gpt' to override
 103  * the test for invalid PMBR.  Not __initdata because reloading
 104  * the partition tables happens after init too.
 105  */
 106 static int force_gpt;
 107 static int __init
 108 force_gpt_fn(char *str)
 109 {
 110         force_gpt = 1;
 111         return 1;
 112 }
 113 __setup("gpt", force_gpt_fn);
 114
 115
 116 /**
 117  * efi_crc32() - EFI version of crc32 function
 118  * @buf: buffer to calculate crc32 of
 119  * @len - length of buf
 120  *
 121  * Description: Returns EFI-style CRC32 value for @buf
 122  *
 123  * This function uses the little endian Ethernet polynomial
 124  * but seeds the function with ~0, and xor's with ~0 at the end.
 125  * Note, the EFI Specification, v1.02, has a reference to
 126  * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
 127  */
 128 static inline u32
 129 efi_crc32(const void *buf, unsigned long len)
 130 {
 131         return (crc32(~0L, buf, len) ^ ~0L);
 132 }
 133
 134 /**
 135  * last_lba(): return number of last logical block of device
 136  * @bdev: block device
 137  *
 138  * Description: Returns last LBA value on success, 0 on error.
 139  * This is stored (by sd and ide-geometry) in
 140  *  the part[0] entry for this disk, and is the number of
 141  *  physical sectors available on the disk.
 142  */
 143 static u64
 144 last_lba(struct block_device *bdev)
 145 {
 146         if (!bdev || !bdev->bd_inode)
 147                 return 0;
 148         return div_u64(bdev->bd_inode->i_size,
 149                        bdev_logical_block_size(bdev)) - 1ULL;
 150 }
 151
 152 static inline int
 153 pmbr_part_valid(struct partition *part)
 154 {
 155         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
 156             le32_to_cpu(part->start_sect) == 1UL)
 157                 return 1;
 158         return 0;
 159 }
 160
 161 /**
 162  * is_pmbr_valid(): test Protective MBR for validity
 163  * @mbr: pointer to a legacy mbr structure
 164  *
 165  * Description: Returns 1 if PMBR is valid, 0 otherwise.
 166  * Validity depends on two things:
 167  *  1) MSDOS signature is in the last two bytes of the MBR
 168  *  2) One partition of type 0xEE is found
 169  */
 170 static int
 171 is_pmbr_valid(legacy_mbr *mbr)
 172 {
 173         int i;
 174         if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
 175                 return 0;
 176         for (i = 0; i < 4; i++)
 177                 if (pmbr_part_valid(&mbr->partition_record[i]))
 178                         return 1;
 179         return 0;
 180 }
 181
 182 /**
 183  * read_lba(): Read bytes from disk, starting at given LBA
 184  * @bdev
 185  * @lba
 186  * @buffer
 187  * @size_t
 188  *
 189  * Description:  Reads @count bytes from @bdev into @buffer.
 190  * Returns number of bytes read on success, 0 on error.
 191  */
 192 static size_t
 193 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
 194 {
 195         size_t totalreadcount = 0;
 196         sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
 197
 198         if (!bdev || !buffer || lba > last_lba(bdev))
 199                 return 0;
 200
 201         while (count) {
 202                 int copied = 512;
 203                 Sector sect;
 204                 unsigned char *data = read_dev_sector(bdev, n++, &sect);
 205                 if (!data)
 206                         break;
 207                 if (copied > count)
 208                         copied = count;
 209                 memcpy(buffer, data, copied);
 210                 put_dev_sector(sect);
 211                 buffer += copied;
 212                 totalreadcount +=copied;
 213                 count -= copied;
 214         }
 215         return totalreadcount;
 216 }
 217
 218 /**
 219  * alloc_read_gpt_entries(): reads partition entries from disk
 220  * @bdev
 221  * @gpt - GPT header
 222  *
 223  * Description: Returns ptes on success,  NULL on error.
 224  * Allocates space for PTEs based on information found in @gpt.
 225  * Notes: remember to free pte when you're done!
 226  */
 227 static gpt_entry *
 228 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
 229 {
 230         size_t count;
 231         gpt_entry *pte;
 232         if (!bdev || !gpt)
 233                 return NULL;
 234
 235         count = le32_to_cpu(gpt->num_partition_entries) *
 236                 le32_to_cpu(gpt->sizeof_partition_entry);
 237         if (!count)
 238                 return NULL;
 239         pte = kzalloc(count, GFP_KERNEL);
 240         if (!pte)
 241                 return NULL;
 242
 243         if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
 244                      (u8 *) pte,
 245                      count) < count) {
 246                 kfree(pte);
 247                 pte=NULL;
 248                 return NULL;
 249         }
 250         return pte;
 251 }
 252
 253 /**
 254  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 255  * @bdev
 256  * @lba is the Logical Block Address of the partition table
 257  *
 258  * Description: returns GPT header on success, NULL on error.   Allocates
 259  * and fills a GPT header starting at @ from @bdev.
 260  * Note: remember to free gpt when finished with it.
 261  */
 262 static gpt_header *
 263 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
 264 {
 265         gpt_header *gpt;
 266         unsigned ssz = bdev_logical_block_size(bdev);
 267
 268         if (!bdev)
 269                 return NULL;
 270
 271         gpt = kzalloc(ssz, GFP_KERNEL);
 272         if (!gpt)
 273                 return NULL;
 274
 275         if (read_lba(bdev, lba, (u8 *) gpt, ssz) < ssz) {
 276                 kfree(gpt);
 277                 gpt=NULL;
 278                 return NULL;
 279         }
 280
 281         return gpt;
 282 }
 283
 284 /**
 285  * is_gpt_valid() - tests one GPT header and PTEs for validity
 286  * @bdev
 287  * @lba is the logical block address of the GPT header to test
 288  * @gpt is a GPT header ptr, filled on return.
 289  * @ptes is a PTEs ptr, filled on return.
 290  *
 291  * Description: returns 1 if valid,  0 on error.
 292  * If valid, returns pointers to newly allocated GPT header and PTEs.
 293  */
 294 static int
 295 is_gpt_valid(struct block_device *bdev, u64 lba,
 296              gpt_header **gpt, gpt_entry **ptes)
 297 {
 298         u32 crc, origcrc;
 299         u64 lastlba;
 300
 301         if (!bdev || !gpt || !ptes)
 302                 return 0;
 303         if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
 304                 return 0;
 305
 306         /* Check the GUID Partition Table signature */
 307         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 308                 pr_debug("GUID Partition Table Header signature is wrong:"
 309                          "%lld != %lld\n",
 310                          (unsigned long long)le64_to_cpu((*gpt)->signature),
 311                          (unsigned long long)GPT_HEADER_SIGNATURE);
 312                 goto fail;
 313         }
 314
 315         /* Check the GUID Partition Table CRC */
 316         origcrc = le32_to_cpu((*gpt)->header_crc32);
 317         (*gpt)->header_crc32 = 0;
 318         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 319
 320         if (crc != origcrc) {
 321                 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
 322                          crc, origcrc);
 323                 goto fail;
 324         }
 325         (*gpt)->header_crc32 = cpu_to_le32(origcrc);
 326
 327         /* Check that the my_lba entry points to the LBA that contains
 328          * the GUID Partition Table */
 329         if (le64_to_cpu((*gpt)->my_lba) != lba) {
 330                 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
 331                          (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 332                          (unsigned long long)lba);
 333                 goto fail;
 334         }
 335
 336         /* Check the first_usable_lba and last_usable_lba are
 337          * within the disk.
 338          */
 339         lastlba = last_lba(bdev);
 340         if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 341                 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 342                          (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
 343                          (unsigned long long)lastlba);
 344                 goto fail;
 345         }
 346         if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
 347                 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
 348                          (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
 349                          (unsigned long long)lastlba);
 350                 goto fail;
 351         }
 352
 353         if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
 354                 goto fail;
 355
 356         /* Check the GUID Partition Entry Array CRC */
 357         crc = efi_crc32((const unsigned char *) (*ptes),
 358                         le32_to_cpu((*gpt)->num_partition_entries) *
 359                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 360
 361         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 362                 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
 363                 goto fail_ptes;
 364         }
 365
 366         /* We're done, all's well */
 367         return 1;
 368
 369  fail_ptes:
 370         kfree(*ptes);
 371         *ptes = NULL;
 372  fail:
 373         kfree(*gpt);
 374         *gpt = NULL;
 375         return 0;
 376 }
 377
 378 /**
 379  * is_pte_valid() - tests one PTE for validity
 380  * @pte is the pte to check
 381  * @lastlba is last lba of the disk
 382  *
 383  * Description: returns 1 if valid,  0 on error.
 384  */
 385 static inline int
 386 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
 387 {
 388         if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
 389             le64_to_cpu(pte->starting_lba) > lastlba         ||
 390             le64_to_cpu(pte->ending_lba)   > lastlba)
 391                 return 0;
 392         return 1;
 393 }
 394
 395 /**
 396  * compare_gpts() - Search disk for valid GPT headers and PTEs
 397  * @pgpt is the primary GPT header
 398  * @agpt is the alternate GPT header
 399  * @lastlba is the last LBA number
 400  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 401  * and prints warnings on discrepancies.
 402  *
 403  */
 404 static void
 405 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 406 {
 407         int error_found = 0;
 408         if (!pgpt || !agpt)
 409                 return;
 410         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 411                 printk(KERN_WARNING
 412                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 413                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 414                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 415                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 416                 error_found++;
 417         }
 418         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 419                 printk(KERN_WARNING
 420                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 421                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 422                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 423                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 424                 error_found++;
 425         }
 426         if (le64_to_cpu(pgpt->first_usable_lba) !=
 427             le64_to_cpu(agpt->first_usable_lba)) {
 428                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 429                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 430                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 431                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 432                 error_found++;
 433         }
 434         if (le64_to_cpu(pgpt->last_usable_lba) !=
 435             le64_to_cpu(agpt->last_usable_lba)) {
 436                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 437                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 438                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 439                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 440                 error_found++;
 441         }
 442         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 443                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 444                 error_found++;
 445         }
 446         if (le32_to_cpu(pgpt->num_partition_entries) !=
 447             le32_to_cpu(agpt->num_partition_entries)) {
 448                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 449                        "0x%x != 0x%x\n",
 450                        le32_to_cpu(pgpt->num_partition_entries),
 451                        le32_to_cpu(agpt->num_partition_entries));
 452                 error_found++;
 453         }
 454         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 455             le32_to_cpu(agpt->sizeof_partition_entry)) {
 456                 printk(KERN_WARNING
 457                        "GPT:sizeof_partition_entry values don't match: "
 458                        "0x%x != 0x%x\n",
 459                        le32_to_cpu(pgpt->sizeof_partition_entry),
 460                        le32_to_cpu(agpt->sizeof_partition_entry));
 461                 error_found++;
 462         }
 463         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 464             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 465                 printk(KERN_WARNING
 466                        "GPT:partition_entry_array_crc32 values don't match: "
 467                        "0x%x != 0x%x\n",
 468                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 469                        le32_to_cpu(agpt->partition_entry_array_crc32));
 470                 error_found++;
 471         }
 472         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 473                 printk(KERN_WARNING
 474                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 475                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 476                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 477                         (unsigned long long)lastlba);
 478                 error_found++;
 479         }
 480
 481         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 482                 printk(KERN_WARNING
 483                        "GPT:Alternate GPT header not at the end of the disk.\n");
 484                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 485                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 486                         (unsigned long long)lastlba);
 487                 error_found++;
 488         }
 489
 490         if (error_found)
 491                 printk(KERN_WARNING
 492                        "GPT: Use GNU Parted to correct GPT errors.\n");
 493         return;
 494 }
 495
 496 /**
 497  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 498  * @bdev
 499  * @gpt is a GPT header ptr, filled on return.
 500  * @ptes is a PTEs ptr, filled on return.
 501  * Description: Returns 1 if valid, 0 on error.
 502  * If valid, returns pointers to newly allocated GPT header and PTEs.
 503  * Validity depends on PMBR being valid (or being overridden by the
 504  * 'gpt' kernel command line option) and finding either the Primary
 505  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
 506  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
 507  * is not checked unless the 'gpt' kernel command line option is passed.
 508  * This protects against devices which misreport their size, and forces
 509  * the user to decide to use the Alternate GPT.
 510  */
 511 static int
 512 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
 513 {
 514         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 515         gpt_header *pgpt = NULL, *agpt = NULL;
 516         gpt_entry *pptes = NULL, *aptes = NULL;
 517         legacy_mbr *legacymbr;
 518         u64 lastlba;
 519         if (!bdev || !gpt || !ptes)
 520                 return 0;
 521
 522         lastlba = last_lba(bdev);
 523         if (!force_gpt) {
 524                 /* This will be added to the EFI Spec. per Intel after v1.02. */
 525                 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
 526                 if (legacymbr) {
 527                         read_lba(bdev, 0, (u8 *) legacymbr,
 528                                  sizeof (*legacymbr));
 529                         good_pmbr = is_pmbr_valid(legacymbr);
 530                         kfree(legacymbr);
 531                 }
 532                 if (!good_pmbr)
 533                         goto fail;
 534         }
 535
 536         good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
 537                                  &pgpt, &pptes);
 538         if (good_pgpt)
 539                 good_agpt = is_gpt_valid(bdev,
 540                                          le64_to_cpu(pgpt->alternate_lba),
 541                                          &agpt, &aptes);
 542         if (!good_agpt && force_gpt)
 543                 good_agpt = is_gpt_valid(bdev, lastlba,
 544                                          &agpt, &aptes);
 545
 546         /* The obviously unsuccessful case */
 547         if (!good_pgpt && !good_agpt)
 548                 goto fail;
 549
 550         compare_gpts(pgpt, agpt, lastlba);
 551
 552         /* The good cases */
 553         if (good_pgpt) {
 554                 *gpt  = pgpt;
 555                 *ptes = pptes;
 556                 kfree(agpt);
 557                 kfree(aptes);
 558                 if (!good_agpt) {
 559                         printk(KERN_WARNING
 560                                "Alternate GPT is invalid, "
 561                                "using primary GPT.\n");
 562                 }
 563                 return 1;
 564         }
 565         else if (good_agpt) {
 566                 *gpt  = agpt;
 567                 *ptes = aptes;
 568                 kfree(pgpt);
 569                 kfree(pptes);
 570                 printk(KERN_WARNING
 571                        "Primary GPT is invalid, using alternate GPT.\n");
 572                 return 1;
 573         }
 574
 575  fail:
 576         kfree(pgpt);
 577         kfree(agpt);
 578         kfree(pptes);
 579         kfree(aptes);
 580         *gpt = NULL;
 581         *ptes = NULL;
 582         return 0;
 583 }
 584
 585 /**
 586  * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 587  * @state
 588  * @bdev
 589  *
 590  * Description: called from check.c, if the disk contains GPT
 591  * partitions, sets up partition entries in the kernel.
 592  *
 593  * If the first block on the disk is a legacy MBR,
 594  * it will get handled by msdos_partition().
 595  * If it's a Protective MBR, we'll handle it here.
 596  *
 597  * We do not create a Linux partition for GPT, but
 598  * only for the actual data partitions.
 599  * Returns:
 600  * -1 if unable to read the partition table
 601  *  0 if this isn't our partition table
 602  *  1 if successful
 603  *
 604  */
 605 int
 606 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 607 {
 608         gpt_header *gpt = NULL;
 609         gpt_entry *ptes = NULL;
 610         u32 i;
 611         unsigned ssz = bdev_logical_block_size(bdev) / 512;
 612
 613         if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
 614                 kfree(gpt);
 615                 kfree(ptes);
 616                 return 0;
 617         }
 618
 619         pr_debug("GUID Partition Table is valid!  Yea!\n");
 620
 621         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 622                 u64 start = le64_to_cpu(ptes[i].starting_lba);
 623                 u64 size = le64_to_cpu(ptes[i].ending_lba) -
 624                            le64_to_cpu(ptes[i].starting_lba) + 1ULL;
 625
 626                 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
 627                         continue;
 628
 629                 put_partition(state, i+1, start * ssz, size * ssz);
 630
 631                 /* If this is a RAID volume, tell md */
 632                 if (!efi_guidcmp(ptes[i].partition_type_guid,
 633                                  PARTITION_LINUX_RAID_GUID))
 634                         state->parts[i+1].flags = 1;
 635         }
 636         kfree(ptes);
 637         kfree(gpt);
 638         printk("\n");
 639         return 1;
 640 }