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 "check.h"
  99 #include "efi.h"
 100
 101 /* This allows a kernel command line option 'gpt' to override
 102  * the test for invalid PMBR.  Not __initdata because reloading
 103  * the partition tables happens after init too.
 104  */
 105 static int force_gpt;
 106 static int __init
 107 force_gpt_fn(char *str)
 108 {
 109         force_gpt = 1;
 110         return 1;
 111 }
 112 __setup("gpt", force_gpt_fn);
 113
 114
 115 /**
 116  * efi_crc32() - EFI version of crc32 function
 117  * @buf: buffer to calculate crc32 of
 118  * @len - length of buf
 119  *
 120  * Description: Returns EFI-style CRC32 value for @buf
 121  *
 122  * This function uses the little endian Ethernet polynomial
 123  * but seeds the function with ~0, and xor's with ~0 at the end.
 124  * Note, the EFI Specification, v1.02, has a reference to
 125  * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
 126  */
 127 static inline u32
 128 efi_crc32(const void *buf, unsigned long len)
 129 {
 130         return (crc32(~0L, buf, len) ^ ~0L);
 131 }
 132
 133 /**
 134  * last_lba(): return number of last logical block of device
 135  * @bdev: block device
 136  *
 137  * Description: Returns last LBA value on success, 0 on error.
 138  * This is stored (by sd and ide-geometry) in
 139  *  the part[0] entry for this disk, and is the number of
 140  *  physical sectors available on the disk.
 141  */
 142 static u64
 143 last_lba(struct block_device *bdev)
 144 {
 145         if (!bdev || !bdev->bd_inode)
 146                 return 0;
 147         return div_u64(bdev->bd_inode->i_size,
 148                        bdev_logical_block_size(bdev)) - 1ULL;
 149 }
 150
 151 static inline int
 152 pmbr_part_valid(struct partition *part)
 153 {
 154         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
 155             le32_to_cpu(part->start_sect) == 1UL)
 156                 return 1;
 157         return 0;
 158 }
 159
 160 /**
 161  * is_pmbr_valid(): test Protective MBR for validity
 162  * @mbr: pointer to a legacy mbr structure
 163  *
 164  * Description: Returns 1 if PMBR is valid, 0 otherwise.
 165  * Validity depends on two things:
 166  *  1) MSDOS signature is in the last two bytes of the MBR
 167  *  2) One partition of type 0xEE is found
 168  */
 169 static int
 170 is_pmbr_valid(legacy_mbr *mbr)
 171 {
 172         int i;
 173         if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
 174                 return 0;
 175         for (i = 0; i < 4; i++)
 176                 if (pmbr_part_valid(&mbr->partition_record[i]))
 177                         return 1;
 178         return 0;
 179 }
 180
 181 /**
 182  * read_lba(): Read bytes from disk, starting at given LBA
 183  * @bdev
 184  * @lba
 185  * @buffer
 186  * @size_t
 187  *
 188  * Description:  Reads @count bytes from @bdev into @buffer.
 189  * Returns number of bytes read on success, 0 on error.
 190  */
 191 static size_t
 192 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
 193 {
 194         size_t totalreadcount = 0;
 195         sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
 196
 197         if (!bdev || !buffer || lba > last_lba(bdev))
 198                 return 0;
 199
 200         while (count) {
 201                 int copied = 512;
 202                 Sector sect;
 203                 unsigned char *data = read_dev_sector(bdev, n++, &sect);
 204                 if (!data)
 205                         break;
 206                 if (copied > count)
 207                         copied = count;
 208                 memcpy(buffer, data, copied);
 209                 put_dev_sector(sect);
 210                 buffer += copied;
 211                 totalreadcount +=copied;
 212                 count -= copied;
 213         }
 214         return totalreadcount;
 215 }
 216
 217 /**
 218  * alloc_read_gpt_entries(): reads partition entries from disk
 219  * @bdev
 220  * @gpt - GPT header
 221  *
 222  * Description: Returns ptes on success,  NULL on error.
 223  * Allocates space for PTEs based on information found in @gpt.
 224  * Notes: remember to free pte when you're done!
 225  */
 226 static gpt_entry *
 227 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
 228 {
 229         size_t count;
 230         gpt_entry *pte;
 231         if (!bdev || !gpt)
 232                 return NULL;
 233
 234         count = le32_to_cpu(gpt->num_partition_entries) *
 235                 le32_to_cpu(gpt->sizeof_partition_entry);
 236         if (!count)
 237                 return NULL;
 238         pte = kzalloc(count, GFP_KERNEL);
 239         if (!pte)
 240                 return NULL;
 241
 242         if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
 243                      (u8 *) pte,
 244                      count) < count) {
 245                 kfree(pte);
 246                 pte=NULL;
 247                 return NULL;
 248         }
 249         return pte;
 250 }
 251
 252 /**
 253  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 254  * @bdev
 255  * @lba is the Logical Block Address of the partition table
 256  *
 257  * Description: returns GPT header on success, NULL on error.   Allocates
 258  * and fills a GPT header starting at @ from @bdev.
 259  * Note: remember to free gpt when finished with it.
 260  */
 261 static gpt_header *
 262 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
 263 {
 264         gpt_header *gpt;
 265         unsigned ssz = bdev_logical_block_size(bdev);
 266
 267         if (!bdev)
 268                 return NULL;
 269
 270         gpt = kzalloc(ssz, GFP_KERNEL);
 271         if (!gpt)
 272                 return NULL;
 273
 274         if (read_lba(bdev, lba, (u8 *) gpt, ssz) < ssz) {
 275                 kfree(gpt);
 276                 gpt=NULL;
 277                 return NULL;
 278         }
 279
 280         return gpt;
 281 }
 282
 283 /**
 284  * is_gpt_valid() - tests one GPT header and PTEs for validity
 285  * @bdev
 286  * @lba is the logical block address of the GPT header to test
 287  * @gpt is a GPT header ptr, filled on return.
 288  * @ptes is a PTEs ptr, filled on return.
 289  *
 290  * Description: returns 1 if valid,  0 on error.
 291  * If valid, returns pointers to newly allocated GPT header and PTEs.
 292  */
 293 static int
 294 is_gpt_valid(struct block_device *bdev, u64 lba,
 295              gpt_header **gpt, gpt_entry **ptes)
 296 {
 297         u32 crc, origcrc;
 298         u64 lastlba;
 299
 300         if (!bdev || !gpt || !ptes)
 301                 return 0;
 302         if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
 303                 return 0;
 304
 305         /* Check the GUID Partition Table signature */
 306         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 307                 pr_debug("GUID Partition Table Header signature is wrong:"
 308                          "%lld != %lld\n",
 309                          (unsigned long long)le64_to_cpu((*gpt)->signature),
 310                          (unsigned long long)GPT_HEADER_SIGNATURE);
 311                 goto fail;
 312         }
 313
 314         /* Check the GUID Partition Table CRC */
 315         origcrc = le32_to_cpu((*gpt)->header_crc32);
 316         (*gpt)->header_crc32 = 0;
 317         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 318
 319         if (crc != origcrc) {
 320                 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
 321                          crc, origcrc);
 322                 goto fail;
 323         }
 324         (*gpt)->header_crc32 = cpu_to_le32(origcrc);
 325
 326         /* Check that the my_lba entry points to the LBA that contains
 327          * the GUID Partition Table */
 328         if (le64_to_cpu((*gpt)->my_lba) != lba) {
 329                 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
 330                          (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 331                          (unsigned long long)lba);
 332                 goto fail;
 333         }
 334
 335         /* Check the first_usable_lba and last_usable_lba are
 336          * within the disk.
 337          */
 338         lastlba = last_lba(bdev);
 339         if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 340                 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 341                          (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
 342                          (unsigned long long)lastlba);
 343                 goto fail;
 344         }
 345         if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
 346                 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
 347                          (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
 348                          (unsigned long long)lastlba);
 349                 goto fail;
 350         }
 351
 352         if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
 353                 goto fail;
 354
 355         /* Check the GUID Partition Entry Array CRC */
 356         crc = efi_crc32((const unsigned char *) (*ptes),
 357                         le32_to_cpu((*gpt)->num_partition_entries) *
 358                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 359
 360         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 361                 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
 362                 goto fail_ptes;
 363         }
 364
 365         /* We're done, all's well */
 366         return 1;
 367
 368  fail_ptes:
 369         kfree(*ptes);
 370         *ptes = NULL;
 371  fail:
 372         kfree(*gpt);
 373         *gpt = NULL;
 374         return 0;
 375 }
 376
 377 /**
 378  * is_pte_valid() - tests one PTE for validity
 379  * @pte is the pte to check
 380  * @lastlba is last lba of the disk
 381  *
 382  * Description: returns 1 if valid,  0 on error.
 383  */
 384 static inline int
 385 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
 386 {
 387         if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
 388             le64_to_cpu(pte->starting_lba) > lastlba         ||
 389             le64_to_cpu(pte->ending_lba)   > lastlba)
 390                 return 0;
 391         return 1;
 392 }
 393
 394 /**
 395  * compare_gpts() - Search disk for valid GPT headers and PTEs
 396  * @pgpt is the primary GPT header
 397  * @agpt is the alternate GPT header
 398  * @lastlba is the last LBA number
 399  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 400  * and prints warnings on discrepancies.
 401  *
 402  */
 403 static void
 404 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 405 {
 406         int error_found = 0;
 407         if (!pgpt || !agpt)
 408                 return;
 409         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 410                 printk(KERN_WARNING
 411                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 412                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 413                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 414                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 415                 error_found++;
 416         }
 417         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 418                 printk(KERN_WARNING
 419                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 420                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 421                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 422                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 423                 error_found++;
 424         }
 425         if (le64_to_cpu(pgpt->first_usable_lba) !=
 426             le64_to_cpu(agpt->first_usable_lba)) {
 427                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 428                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 429                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 430                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 431                 error_found++;
 432         }
 433         if (le64_to_cpu(pgpt->last_usable_lba) !=
 434             le64_to_cpu(agpt->last_usable_lba)) {
 435                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 436                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 437                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 438                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 439                 error_found++;
 440         }
 441         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 442                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 443                 error_found++;
 444         }
 445         if (le32_to_cpu(pgpt->num_partition_entries) !=
 446             le32_to_cpu(agpt->num_partition_entries)) {
 447                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 448                        "0x%x != 0x%x\n",
 449                        le32_to_cpu(pgpt->num_partition_entries),
 450                        le32_to_cpu(agpt->num_partition_entries));
 451                 error_found++;
 452         }
 453         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 454             le32_to_cpu(agpt->sizeof_partition_entry)) {
 455                 printk(KERN_WARNING
 456                        "GPT:sizeof_partition_entry values don't match: "
 457                        "0x%x != 0x%x\n",
 458                        le32_to_cpu(pgpt->sizeof_partition_entry),
 459                        le32_to_cpu(agpt->sizeof_partition_entry));
 460                 error_found++;
 461         }
 462         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 463             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 464                 printk(KERN_WARNING
 465                        "GPT:partition_entry_array_crc32 values don't match: "
 466                        "0x%x != 0x%x\n",
 467                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 468                        le32_to_cpu(agpt->partition_entry_array_crc32));
 469                 error_found++;
 470         }
 471         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 472                 printk(KERN_WARNING
 473                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 474                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 475                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 476                         (unsigned long long)lastlba);
 477                 error_found++;
 478         }
 479
 480         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 481                 printk(KERN_WARNING
 482                        "GPT:Alternate GPT header not at the end of the disk.\n");
 483                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 484                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 485                         (unsigned long long)lastlba);
 486                 error_found++;
 487         }
 488
 489         if (error_found)
 490                 printk(KERN_WARNING
 491                        "GPT: Use GNU Parted to correct GPT errors.\n");
 492         return;
 493 }
 494
 495 /**
 496  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 497  * @bdev
 498  * @gpt is a GPT header ptr, filled on return.
 499  * @ptes is a PTEs ptr, filled on return.
 500  * Description: Returns 1 if valid, 0 on error.
 501  * If valid, returns pointers to newly allocated GPT header and PTEs.
 502  * Validity depends on PMBR being valid (or being overridden by the
 503  * 'gpt' kernel command line option) and finding either the Primary
 504  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
 505  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
 506  * is not checked unless the 'gpt' kernel command line option is passed.
 507  * This protects against devices which misreport their size, and forces
 508  * the user to decide to use the Alternate GPT.
 509  */
 510 static int
 511 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
 512 {
 513         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 514         gpt_header *pgpt = NULL, *agpt = NULL;
 515         gpt_entry *pptes = NULL, *aptes = NULL;
 516         legacy_mbr *legacymbr;
 517         u64 lastlba;
 518         if (!bdev || !gpt || !ptes)
 519                 return 0;
 520
 521         lastlba = last_lba(bdev);
 522         if (!force_gpt) {
 523                 /* This will be added to the EFI Spec. per Intel after v1.02. */
 524                 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
 525                 if (legacymbr) {
 526                         read_lba(bdev, 0, (u8 *) legacymbr,
 527                                  sizeof (*legacymbr));
 528                         good_pmbr = is_pmbr_valid(legacymbr);
 529                         kfree(legacymbr);
 530                 }
 531                 if (!good_pmbr)
 532                         goto fail;
 533         }
 534
 535         good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
 536                                  &pgpt, &pptes);
 537         if (good_pgpt)
 538                 good_agpt = is_gpt_valid(bdev,
 539                                          le64_to_cpu(pgpt->alternate_lba),
 540                                          &agpt, &aptes);
 541         if (!good_agpt && force_gpt)
 542                 good_agpt = is_gpt_valid(bdev, lastlba,
 543                                          &agpt, &aptes);
 544
 545         /* The obviously unsuccessful case */
 546         if (!good_pgpt && !good_agpt)
 547                 goto fail;
 548
 549         compare_gpts(pgpt, agpt, lastlba);
 550
 551         /* The good cases */
 552         if (good_pgpt) {
 553                 *gpt  = pgpt;
 554                 *ptes = pptes;
 555                 kfree(agpt);
 556                 kfree(aptes);
 557                 if (!good_agpt) {
 558                         printk(KERN_WARNING
 559                                "Alternate GPT is invalid, "
 560                                "using primary GPT.\n");
 561                 }
 562                 return 1;
 563         }
 564         else if (good_agpt) {
 565                 *gpt  = agpt;
 566                 *ptes = aptes;
 567                 kfree(pgpt);
 568                 kfree(pptes);
 569                 printk(KERN_WARNING
 570                        "Primary GPT is invalid, using alternate GPT.\n");
 571                 return 1;
 572         }
 573
 574  fail:
 575         kfree(pgpt);
 576         kfree(agpt);
 577         kfree(pptes);
 578         kfree(aptes);
 579         *gpt = NULL;
 580         *ptes = NULL;
 581         return 0;
 582 }
 583
 584 /**
 585  * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 586  * @state
 587  * @bdev
 588  *
 589  * Description: called from check.c, if the disk contains GPT
 590  * partitions, sets up partition entries in the kernel.
 591  *
 592  * If the first block on the disk is a legacy MBR,
 593  * it will get handled by msdos_partition().
 594  * If it's a Protective MBR, we'll handle it here.
 595  *
 596  * We do not create a Linux partition for GPT, but
 597  * only for the actual data partitions.
 598  * Returns:
 599  * -1 if unable to read the partition table
 600  *  0 if this isn't our partition table
 601  *  1 if successful
 602  *
 603  */
 604 int
 605 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 606 {
 607         gpt_header *gpt = NULL;
 608         gpt_entry *ptes = NULL;
 609         u32 i;
 610         unsigned ssz = bdev_logical_block_size(bdev) / 512;
 611
 612         if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
 613                 kfree(gpt);
 614                 kfree(ptes);
 615                 return 0;
 616         }
 617
 618         pr_debug("GUID Partition Table is valid!  Yea!\n");
 619
 620         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 621                 u64 start = le64_to_cpu(ptes[i].starting_lba);
 622                 u64 size = le64_to_cpu(ptes[i].ending_lba) -
 623                            le64_to_cpu(ptes[i].starting_lba) + 1ULL;
 624
 625                 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
 626                         continue;
 627
 628                 put_partition(state, i+1, start * ssz, size * ssz);
 629
 630                 /* If this is a RAID volume, tell md */
 631                 if (!efi_guidcmp(ptes[i].partition_type_guid,
 632                                  PARTITION_LINUX_RAID_GUID))
 633                         state->parts[i+1].flags = 1;
 634         }
 635         kfree(ptes);
 636         kfree(gpt);
 637         printk("\n");
 638         return 1;
 639 }