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 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  * @state
 184  * @lba
 185  * @buffer
 186  * @size_t
 187  *
 188  * Description: Reads @count bytes from @state->bdev into @buffer.
 189  * Returns number of bytes read on success, 0 on error.
 190  */
 191 static size_t read_lba(struct parsed_partitions *state,
 192                        u64 lba, u8 *buffer, size_t count)
 193 {
 194         size_t totalreadcount = 0;
 195         struct block_device *bdev = state->bdev;
 196         sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
 197
 198         if (!buffer || lba > last_lba(bdev))
 199                 return 0;
 200
 201         while (count) {
 202                 int copied = 512;
 203                 Sector sect;
 204                 unsigned char *data = read_part_sector(state, 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  * @state
 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 *alloc_read_gpt_entries(struct parsed_partitions *state,
 228                                          gpt_header *gpt)
 229 {
 230         size_t count;
 231         gpt_entry *pte;
 232
 233         if (!gpt)
 234                 return NULL;
 235
 236         count = le32_to_cpu(gpt->num_partition_entries) *
 237                 le32_to_cpu(gpt->sizeof_partition_entry);
 238         if (!count)
 239                 return NULL;
 240         pte = kzalloc(count, GFP_KERNEL);
 241         if (!pte)
 242                 return NULL;
 243
 244         if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
 245                      (u8 *) pte,
 246                      count) < count) {
 247                 kfree(pte);
 248                 pte=NULL;
 249                 return NULL;
 250         }
 251         return pte;
 252 }
 253
 254 /**
 255  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 256  * @state
 257  * @lba is the Logical Block Address of the partition table
 258  *
 259  * Description: returns GPT header on success, NULL on error.   Allocates
 260  * and fills a GPT header starting at @ from @state->bdev.
 261  * Note: remember to free gpt when finished with it.
 262  */
 263 static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
 264                                          u64 lba)
 265 {
 266         gpt_header *gpt;
 267         unsigned ssz = bdev_logical_block_size(state->bdev);
 268
 269         gpt = kzalloc(ssz, GFP_KERNEL);
 270         if (!gpt)
 271                 return NULL;
 272
 273         if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {
 274                 kfree(gpt);
 275                 gpt=NULL;
 276                 return NULL;
 277         }
 278
 279         return gpt;
 280 }
 281
 282 /**
 283  * is_gpt_valid() - tests one GPT header and PTEs for validity
 284  * @state
 285  * @lba is the logical block address of the GPT header to test
 286  * @gpt is a GPT header ptr, filled on return.
 287  * @ptes is a PTEs ptr, filled on return.
 288  *
 289  * Description: returns 1 if valid,  0 on error.
 290  * If valid, returns pointers to newly allocated GPT header and PTEs.
 291  */
 292 static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
 293                         gpt_header **gpt, gpt_entry **ptes)
 294 {
 295         u32 crc, origcrc;
 296         u64 lastlba;
 297
 298         if (!ptes)
 299                 return 0;
 300         if (!(*gpt = alloc_read_gpt_header(state, lba)))
 301                 return 0;
 302
 303         /* Check the GUID Partition Table signature */
 304         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 305                 pr_debug("GUID Partition Table Header signature is wrong:"
 306                          "%lld != %lld\n",
 307                          (unsigned long long)le64_to_cpu((*gpt)->signature),
 308                          (unsigned long long)GPT_HEADER_SIGNATURE);
 309                 goto fail;
 310         }
 311
 312         /* Check the GUID Partition Table CRC */
 313         origcrc = le32_to_cpu((*gpt)->header_crc32);
 314         (*gpt)->header_crc32 = 0;
 315         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 316
 317         if (crc != origcrc) {
 318                 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
 319                          crc, origcrc);
 320                 goto fail;
 321         }
 322         (*gpt)->header_crc32 = cpu_to_le32(origcrc);
 323
 324         /* Check that the my_lba entry points to the LBA that contains
 325          * the GUID Partition Table */
 326         if (le64_to_cpu((*gpt)->my_lba) != lba) {
 327                 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
 328                          (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 329                          (unsigned long long)lba);
 330                 goto fail;
 331         }
 332
 333         /* Check the first_usable_lba and last_usable_lba are
 334          * within the disk.
 335          */
 336         lastlba = last_lba(state->bdev);
 337         if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 338                 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 339                          (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
 340                          (unsigned long long)lastlba);
 341                 goto fail;
 342         }
 343         if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
 344                 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
 345                          (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
 346                          (unsigned long long)lastlba);
 347                 goto fail;
 348         }
 349
 350         if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
 351                 goto fail;
 352
 353         /* Check the GUID Partition Entry Array CRC */
 354         crc = efi_crc32((const unsigned char *) (*ptes),
 355                         le32_to_cpu((*gpt)->num_partition_entries) *
 356                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 357
 358         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 359                 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
 360                 goto fail_ptes;
 361         }
 362
 363         /* We're done, all's well */
 364         return 1;
 365
 366  fail_ptes:
 367         kfree(*ptes);
 368         *ptes = NULL;
 369  fail:
 370         kfree(*gpt);
 371         *gpt = NULL;
 372         return 0;
 373 }
 374
 375 /**
 376  * is_pte_valid() - tests one PTE for validity
 377  * @pte is the pte to check
 378  * @lastlba is last lba of the disk
 379  *
 380  * Description: returns 1 if valid,  0 on error.
 381  */
 382 static inline int
 383 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
 384 {
 385         if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
 386             le64_to_cpu(pte->starting_lba) > lastlba         ||
 387             le64_to_cpu(pte->ending_lba)   > lastlba)
 388                 return 0;
 389         return 1;
 390 }
 391
 392 /**
 393  * compare_gpts() - Search disk for valid GPT headers and PTEs
 394  * @pgpt is the primary GPT header
 395  * @agpt is the alternate GPT header
 396  * @lastlba is the last LBA number
 397  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 398  * and prints warnings on discrepancies.
 399  *
 400  */
 401 static void
 402 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 403 {
 404         int error_found = 0;
 405         if (!pgpt || !agpt)
 406                 return;
 407         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 408                 printk(KERN_WARNING
 409                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 410                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 411                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 412                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 413                 error_found++;
 414         }
 415         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 416                 printk(KERN_WARNING
 417                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 418                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 419                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 420                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 421                 error_found++;
 422         }
 423         if (le64_to_cpu(pgpt->first_usable_lba) !=
 424             le64_to_cpu(agpt->first_usable_lba)) {
 425                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 426                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 427                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 428                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 429                 error_found++;
 430         }
 431         if (le64_to_cpu(pgpt->last_usable_lba) !=
 432             le64_to_cpu(agpt->last_usable_lba)) {
 433                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 434                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 435                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 436                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 437                 error_found++;
 438         }
 439         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 440                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 441                 error_found++;
 442         }
 443         if (le32_to_cpu(pgpt->num_partition_entries) !=
 444             le32_to_cpu(agpt->num_partition_entries)) {
 445                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 446                        "0x%x != 0x%x\n",
 447                        le32_to_cpu(pgpt->num_partition_entries),
 448                        le32_to_cpu(agpt->num_partition_entries));
 449                 error_found++;
 450         }
 451         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 452             le32_to_cpu(agpt->sizeof_partition_entry)) {
 453                 printk(KERN_WARNING
 454                        "GPT:sizeof_partition_entry values don't match: "
 455                        "0x%x != 0x%x\n",
 456                        le32_to_cpu(pgpt->sizeof_partition_entry),
 457                        le32_to_cpu(agpt->sizeof_partition_entry));
 458                 error_found++;
 459         }
 460         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 461             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 462                 printk(KERN_WARNING
 463                        "GPT:partition_entry_array_crc32 values don't match: "
 464                        "0x%x != 0x%x\n",
 465                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 466                        le32_to_cpu(agpt->partition_entry_array_crc32));
 467                 error_found++;
 468         }
 469         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 470                 printk(KERN_WARNING
 471                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 472                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 473                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 474                         (unsigned long long)lastlba);
 475                 error_found++;
 476         }
 477
 478         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 479                 printk(KERN_WARNING
 480                        "GPT:Alternate GPT header not at the end of the disk.\n");
 481                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 482                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 483                         (unsigned long long)lastlba);
 484                 error_found++;
 485         }
 486
 487         if (error_found)
 488                 printk(KERN_WARNING
 489                        "GPT: Use GNU Parted to correct GPT errors.\n");
 490         return;
 491 }
 492
 493 /**
 494  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 495  * @state
 496  * @gpt is a GPT header ptr, filled on return.
 497  * @ptes is a PTEs ptr, filled on return.
 498  * Description: Returns 1 if valid, 0 on error.
 499  * If valid, returns pointers to newly allocated GPT header and PTEs.
 500  * Validity depends on PMBR being valid (or being overridden by the
 501  * 'gpt' kernel command line option) and finding either the Primary
 502  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
 503  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
 504  * is not checked unless the 'gpt' kernel command line option is passed.
 505  * This protects against devices which misreport their size, and forces
 506  * the user to decide to use the Alternate GPT.
 507  */
 508 static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
 509                           gpt_entry **ptes)
 510 {
 511         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 512         gpt_header *pgpt = NULL, *agpt = NULL;
 513         gpt_entry *pptes = NULL, *aptes = NULL;
 514         legacy_mbr *legacymbr;
 515         u64 lastlba;
 516
 517         if (!ptes)
 518                 return 0;
 519
 520         lastlba = last_lba(state->bdev);
 521         if (!force_gpt) {
 522                 /* This will be added to the EFI Spec. per Intel after v1.02. */
 523                 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
 524                 if (legacymbr) {
 525                         read_lba(state, 0, (u8 *) legacymbr,
 526                                  sizeof (*legacymbr));
 527                         good_pmbr = is_pmbr_valid(legacymbr);
 528                         kfree(legacymbr);
 529                 }
 530                 if (!good_pmbr)
 531                         goto fail;
 532         }
 533
 534         good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
 535                                  &pgpt, &pptes);
 536         if (good_pgpt)
 537                 good_agpt = is_gpt_valid(state,
 538                                          le64_to_cpu(pgpt->alternate_lba),
 539                                          &agpt, &aptes);
 540         if (!good_agpt && force_gpt)
 541                 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
 542
 543         /* The obviously unsuccessful case */
 544         if (!good_pgpt && !good_agpt)
 545                 goto fail;
 546
 547         compare_gpts(pgpt, agpt, lastlba);
 548
 549         /* The good cases */
 550         if (good_pgpt) {
 551                 *gpt  = pgpt;
 552                 *ptes = pptes;
 553                 kfree(agpt);
 554                 kfree(aptes);
 555                 if (!good_agpt) {
 556                         printk(KERN_WARNING
 557                                "Alternate GPT is invalid, "
 558                                "using primary GPT.\n");
 559                 }
 560                 return 1;
 561         }
 562         else if (good_agpt) {
 563                 *gpt  = agpt;
 564                 *ptes = aptes;
 565                 kfree(pgpt);
 566                 kfree(pptes);
 567                 printk(KERN_WARNING
 568                        "Primary GPT is invalid, using alternate GPT.\n");
 569                 return 1;
 570         }
 571
 572  fail:
 573         kfree(pgpt);
 574         kfree(agpt);
 575         kfree(pptes);
 576         kfree(aptes);
 577         *gpt = NULL;
 578         *ptes = NULL;
 579         return 0;
 580 }
 581
 582 /**
 583  * efi_partition(struct parsed_partitions *state)
 584  * @state
 585  *
 586  * Description: called from check.c, if the disk contains GPT
 587  * partitions, sets up partition entries in the kernel.
 588  *
 589  * If the first block on the disk is a legacy MBR,
 590  * it will get handled by msdos_partition().
 591  * If it's a Protective MBR, we'll handle it here.
 592  *
 593  * We do not create a Linux partition for GPT, but
 594  * only for the actual data partitions.
 595  * Returns:
 596  * -1 if unable to read the partition table
 597  *  0 if this isn't our partition table
 598  *  1 if successful
 599  *
 600  */
 601 int efi_partition(struct parsed_partitions *state)
 602 {
 603         gpt_header *gpt = NULL;
 604         gpt_entry *ptes = NULL;
 605         u32 i;
 606         unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
 607
 608         if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
 609                 kfree(gpt);
 610                 kfree(ptes);
 611                 return 0;
 612         }
 613
 614         pr_debug("GUID Partition Table is valid!  Yea!\n");
 615
 616         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 617                 u64 start = le64_to_cpu(ptes[i].starting_lba);
 618                 u64 size = le64_to_cpu(ptes[i].ending_lba) -
 619                            le64_to_cpu(ptes[i].starting_lba) + 1ULL;
 620
 621                 if (!is_pte_valid(&ptes[i], last_lba(state->bdev)))
 622                         continue;
 623
 624                 put_partition(state, i+1, start * ssz, size * ssz);
 625
 626                 /* If this is a RAID volume, tell md */
 627                 if (!efi_guidcmp(ptes[i].partition_type_guid,
 628                                  PARTITION_LINUX_RAID_GUID))
 629                         state->parts[i + 1].flags = ADDPART_FLAG_RAID;
 630         }
 631         kfree(ptes);
 632         kfree(gpt);
 633         printk("\n");
 634         return 1;
 635 }