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 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  * Tue  Mar 26 2002 Matt Domsch <Matt_Domsch@dell.com>
  27  * - Ported to 2.5.7-pre1 and 2.5.7-dj2
  28  * - Applied patch to avoid fault in alternate header handling
  29  * - cleaned up find_valid_gpt
  30  * - On-disk structure and copy in memory is *always* LE now -
  31  *   swab fields as needed
  32  * - remove print_gpt_header()
  33  * - only use first max_p partition entries, to keep the kernel minor number
  34  *   and partition numbers tied.
  35  *
  36  * Mon  Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
  37  * - Removed __PRIPTR_PREFIX - not being used
  38  *
  39  * Mon  Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
  40  * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
  41  *
  42  * Thu Dec 6 2001 Matt Domsch <Matt_Domsch@dell.com>
  43  * - Added compare_gpts().
  44  * - moved le_efi_guid_to_cpus() back into this file.  GPT is the only
  45  *   thing that keeps EFI GUIDs on disk.
  46  * - Changed gpt structure names and members to be simpler and more Linux-like.
  47  *
  48  * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
  49  * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
  50  *
  51  * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
  52  * - Changed function comments to DocBook style per Andreas Dilger suggestion.
  53  *
  54  * Mon Oct 08 2001 Matt Domsch <Matt_Domsch@dell.com>
  55  * - Change read_lba() to use the page cache per Al Viro's work.
  56  * - print u64s properly on all architectures
  57  * - fixed debug_printk(), now Dprintk()
  58  *
  59  * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
  60  * - Style cleanups
  61  * - made most functions static
  62  * - Endianness addition
  63  * - remove test for second alternate header, as it's not per spec,
  64  *   and is unnecessary.  There's now a method to read/write the last
  65  *   sector of an odd-sized disk from user space.  No tools have ever
  66  *   been released which used this code, so it's effectively dead.
  67  * - Per Asit Mallick of Intel, added a test for a valid PMBR.
  68  * - Added kernel command line option 'gpt' to override valid PMBR test.
  69  *
  70  * Wed Jun  6 2001 Martin Wilck <Martin.Wilck@Fujitsu-Siemens.com>
  71  * - added devfs volume UUID support (/dev/volumes/uuids) for
  72  *   mounting file systems by the partition GUID.
  73  *
  74  * Tue Dec  5 2000 Matt Domsch <Matt_Domsch@dell.com>
  75  * - Moved crc32() to linux/lib, added efi_crc32().
  76  *
  77  * Thu Nov 30 2000 Matt Domsch <Matt_Domsch@dell.com>
  78  * - Replaced Intel's CRC32 function with an equivalent
  79  *   non-license-restricted version.
  80  *
  81  * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
  82  * - Fixed the last_lba() call to return the proper last block
  83  *
  84  * Thu Oct 12 2000 Matt Domsch <Matt_Domsch@dell.com>
  85  * - Thanks to Andries Brouwer for his debugging assistance.
  86  * - Code works, detects all the partitions.
  87  *
  88  ************************************************************/
  89 #include <linux/config.h>
  90 #include <linux/crc32.h>
  91 #include "check.h"
  92 #include "efi.h"
  93
  94 #undef EFI_DEBUG
  95 #ifdef EFI_DEBUG
  96 #define Dprintk(x...) printk(KERN_DEBUG x)
  97 #else
  98 #define Dprintk(x...)
  99 #endif
 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  * is_pmbr_valid(): test Protective MBR for validity
 135  * @mbr: pointer to a legacy mbr structure
 136  *
 137  * Description: Returns 1 if PMBR is valid, 0 otherwise.
 138  * Validity depends on two things:
 139  *  1) MSDOS signature is in the last two bytes of the MBR
 140  *  2) One partition of type 0xEE is found
 141  */
 142 static int
 143 is_pmbr_valid(legacy_mbr *mbr)
 144 {
 145         int i, found = 0, signature = 0;
 146         if (!mbr)
 147                 return 0;
 148         signature = (le16_to_cpu(mbr->signature) == MSDOS_MBR_SIGNATURE);
 149         for (i = 0; signature && i < 4; i++) {
 150                 if (mbr->partition_record[i].sys_ind ==
 151                     EFI_PMBR_OSTYPE_EFI_GPT) {
 152                         found = 1;
 153                         break;
 154                 }
 155         }
 156         return (signature && found);
 157 }
 158
 159 /**
 160  * last_lba(): return number of last logical block of device
 161  * @bdev: block device
 162  *
 163  * Description: Returns last LBA value on success, 0 on error.
 164  * This is stored (by sd and ide-geometry) in
 165  *  the part[0] entry for this disk, and is the number of
 166  *  physical sectors available on the disk.
 167  */
 168 static u64
 169 last_lba(struct block_device *bdev)
 170 {
 171         return (bdev->bd_inode->i_size >> 9) - 1;
 172 }
 173
 174 /**
 175  * read_lba(): Read bytes from disk, starting at given LBA
 176  * @bdev
 177  * @lba
 178  * @buffer
 179  * @size_t
 180  *
 181  * Description:  Reads @count bytes from @bdev into @buffer.
 182  * Returns number of bytes read on success, 0 on error.
 183  */
 184 static size_t
 185 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
 186 {
 187         size_t totalreadcount = 0;
 188
 189         if (!bdev || !buffer)
 190                 return 0;
 191
 192         while (count) {
 193                 int copied = 512;
 194                 Sector sect;
 195                 unsigned char *data = read_dev_sector(bdev, lba++, &sect);
 196                 if (!data)
 197                         break;
 198                 if (copied > count)
 199                         copied = count;
 200                 memcpy(buffer, data, copied);
 201                 put_dev_sector(sect);
 202                 buffer += copied;
 203                 totalreadcount +=copied;
 204                 count -= copied;
 205         }
 206         return totalreadcount;
 207 }
 208
 209
 210 /**
 211  * alloc_read_gpt_entries(): reads partition entries from disk
 212  * @bdev
 213  * @gpt - GPT header
 214  *
 215  * Description: Returns ptes on success,  NULL on error.
 216  * Allocates space for PTEs based on information found in @gpt.
 217  * Notes: remember to free pte when you're done!
 218  */
 219 static gpt_entry *
 220 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
 221 {
 222         size_t count;
 223         gpt_entry *pte;
 224         if (!bdev || !gpt)
 225                 return NULL;
 226
 227         count = le32_to_cpu(gpt->num_partition_entries) *
 228                 le32_to_cpu(gpt->sizeof_partition_entry);
 229         if (!count)
 230                 return NULL;
 231         pte = kmalloc(count, GFP_KERNEL);
 232         if (!pte)
 233                 return NULL;
 234         memset(pte, 0, count);
 235
 236         if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
 237                      (u8 *) pte,
 238                      count) < count) {
 239                 kfree(pte);
 240                 pte=NULL;
 241                 return NULL;
 242         }
 243         return pte;
 244 }
 245
 246 /**
 247  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 248  * @bdev
 249  * @lba is the Logical Block Address of the partition table
 250  *
 251  * Description: returns GPT header on success, NULL on error.   Allocates
 252  * and fills a GPT header starting at @ from @bdev.
 253  * Note: remember to free gpt when finished with it.
 254  */
 255 static gpt_header *
 256 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
 257 {
 258         gpt_header *gpt;
 259         if (!bdev)
 260                 return NULL;
 261
 262         gpt = kmalloc(sizeof (gpt_header), GFP_KERNEL);
 263         if (!gpt)
 264                 return NULL;
 265         memset(gpt, 0, sizeof (gpt_header));
 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
 293         if (!bdev || !gpt || !ptes)
 294                 return 0;
 295         if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
 296                 return 0;
 297
 298         /* Check the GUID Partition Table signature */
 299         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 300                 Dprintk("GUID Partition Table Header signature is wrong:"
 301                         "%lld != %lld\n",
 302                         (unsigned long long)le64_to_cpu((*gpt)->signature),
 303                         (unsigned long long)GPT_HEADER_SIGNATURE);
 304                 kfree(*gpt);
 305                 *gpt = NULL;
 306                 return 0;
 307         }
 308
 309         /* Check the GUID Partition Table CRC */
 310         origcrc = le32_to_cpu((*gpt)->header_crc32);
 311         (*gpt)->header_crc32 = 0;
 312         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 313
 314         if (crc != origcrc) {
 315                 Dprintk
 316                     ("GUID Partition Table Header CRC is wrong: %x != %x\n",
 317                      crc, origcrc);
 318                 kfree(*gpt);
 319                 *gpt = NULL;
 320                 return 0;
 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                 Dprintk("GPT my_lba incorrect: %lld != %lld\n",
 328                         (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 329                         (unsigned long long)lba);
 330                 kfree(*gpt);
 331                 *gpt = NULL;
 332                 return 0;
 333         }
 334
 335         if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt))) {
 336                 kfree(*gpt);
 337                 *gpt = NULL;
 338                 return 0;
 339         }
 340
 341         /* Check the GUID Partition Entry Array CRC */
 342         crc = efi_crc32((const unsigned char *) (*ptes),
 343                         le32_to_cpu((*gpt)->num_partition_entries) *
 344                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 345
 346         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 347                 Dprintk("GUID Partitition Entry Array CRC check failed.\n");
 348                 kfree(*gpt);
 349                 *gpt = NULL;
 350                 kfree(*ptes);
 351                 *ptes = NULL;
 352                 return 0;
 353         }
 354
 355         /* We're done, all's well */
 356         return 1;
 357 }
 358
 359 /**
 360  * compare_gpts() - Search disk for valid GPT headers and PTEs
 361  * @pgpt is the primary GPT header
 362  * @agpt is the alternate GPT header
 363  * @lastlba is the last LBA number
 364  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 365  * and prints warnings on discrepancies.
 366  *
 367  */
 368 static void
 369 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 370 {
 371         int error_found = 0;
 372         if (!pgpt || !agpt)
 373                 return;
 374         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 375                 printk(KERN_WARNING
 376                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 377                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 378                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 379                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 380                 error_found++;
 381         }
 382         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 383                 printk(KERN_WARNING
 384                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 385                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 386                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 387                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 388                 error_found++;
 389         }
 390         if (le64_to_cpu(pgpt->first_usable_lba) !=
 391             le64_to_cpu(agpt->first_usable_lba)) {
 392                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 393                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 394                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 395                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 396                 error_found++;
 397         }
 398         if (le64_to_cpu(pgpt->last_usable_lba) !=
 399             le64_to_cpu(agpt->last_usable_lba)) {
 400                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 401                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 402                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 403                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 404                 error_found++;
 405         }
 406         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 407                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 408                 error_found++;
 409         }
 410         if (le32_to_cpu(pgpt->num_partition_entries) !=
 411             le32_to_cpu(agpt->num_partition_entries)) {
 412                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 413                        "0x%x != 0x%x\n",
 414                        le32_to_cpu(pgpt->num_partition_entries),
 415                        le32_to_cpu(agpt->num_partition_entries));
 416                 error_found++;
 417         }
 418         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 419             le32_to_cpu(agpt->sizeof_partition_entry)) {
 420                 printk(KERN_WARNING
 421                        "GPT:sizeof_partition_entry values don't match: "
 422                        "0x%x != 0x%x\n",
 423                        le32_to_cpu(pgpt->sizeof_partition_entry),
 424                        le32_to_cpu(agpt->sizeof_partition_entry));
 425                 error_found++;
 426         }
 427         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 428             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 429                 printk(KERN_WARNING
 430                        "GPT:partition_entry_array_crc32 values don't match: "
 431                        "0x%x != 0x%x\n",
 432                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 433                        le32_to_cpu(agpt->partition_entry_array_crc32));
 434                 error_found++;
 435         }
 436         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 437                 printk(KERN_WARNING
 438                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 439                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 440                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 441                         (unsigned long long)lastlba);
 442                 error_found++;
 443         }
 444
 445         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 446                 printk(KERN_WARNING
 447                        "GPT:Alternate GPT header not at the end of the disk.\n");
 448                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 449                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 450                         (unsigned long long)lastlba);
 451                 error_found++;
 452         }
 453
 454         if (error_found)
 455                 printk(KERN_WARNING
 456                        "GPT: Use GNU Parted to correct GPT errors.\n");
 457         return;
 458 }
 459
 460 /**
 461  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 462  * @bdev
 463  * @gpt is a GPT header ptr, filled on return.
 464  * @ptes is a PTEs ptr, filled on return.
 465  * Description: Returns 1 if valid, 0 on error.
 466  * If valid, returns pointers to newly allocated GPT header and PTEs.
 467  * Validity depends on finding either the Primary GPT header and PTEs valid,
 468  * or the Alternate GPT header and PTEs valid, and the PMBR valid.
 469  */
 470 static int
 471 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
 472 {
 473         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 474         gpt_header *pgpt = NULL, *agpt = NULL;
 475         gpt_entry *pptes = NULL, *aptes = NULL;
 476         legacy_mbr *legacymbr = NULL;
 477         u64 lastlba;
 478         if (!bdev || !gpt || !ptes)
 479                 return 0;
 480
 481         lastlba = last_lba(bdev);
 482         good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
 483                                  &pgpt, &pptes);
 484         if (good_pgpt) {
 485                 good_agpt = is_gpt_valid(bdev,
 486                                          le64_to_cpu(pgpt->alternate_lba),
 487                                          &agpt, &aptes);
 488                 if (!good_agpt) {
 489                         good_agpt = is_gpt_valid(bdev, lastlba,
 490                                                  &agpt, &aptes);
 491                 }
 492         }
 493         else {
 494                 good_agpt = is_gpt_valid(bdev, lastlba,
 495                                          &agpt, &aptes);
 496         }
 497
 498         /* The obviously unsuccessful case */
 499         if (!good_pgpt && !good_agpt) {
 500                 goto fail;
 501         }
 502
 503         /* This will be added to the EFI Spec. per Intel after v1.02. */
 504         legacymbr = kmalloc(sizeof (*legacymbr), GFP_KERNEL);
 505         if (legacymbr) {
 506                 memset(legacymbr, 0, sizeof (*legacymbr));
 507                 read_lba(bdev, 0, (u8 *) legacymbr,
 508                          sizeof (*legacymbr));
 509                 good_pmbr = is_pmbr_valid(legacymbr);
 510                 kfree(legacymbr);
 511                 legacymbr=NULL;
 512         }
 513
 514         /* Failure due to bad PMBR */
 515         if ((good_pgpt || good_agpt) && !good_pmbr && !force_gpt) {
 516                 printk(KERN_WARNING
 517                        "  Warning: Disk has a valid GPT signature "
 518                        "but invalid PMBR.\n");
 519                 printk(KERN_WARNING
 520                        "  Assuming this disk is *not* a GPT disk anymore.\n");
 521                 printk(KERN_WARNING
 522                        "  Use gpt kernel option to override.  "
 523                        "Use GNU Parted to correct disk.\n");
 524                 goto fail;
 525         }
 526
 527         /* Would fail due to bad PMBR, but force GPT anyhow */
 528         if ((good_pgpt || good_agpt) && !good_pmbr && force_gpt) {
 529                 printk(KERN_WARNING
 530                        "  Warning: Disk has a valid GPT signature but "
 531                        "invalid PMBR.\n");
 532                 printk(KERN_WARNING
 533                        "  Use GNU Parted to correct disk.\n");
 534                 printk(KERN_WARNING
 535                        "  gpt option taken, disk treated as GPT.\n");
 536         }
 537
 538         compare_gpts(pgpt, agpt, lastlba);
 539
 540         /* The good cases */
 541         if (good_pgpt && (good_pmbr || force_gpt)) {
 542                 *gpt  = pgpt;
 543                 *ptes = pptes;
 544                 if (agpt)  { kfree(agpt);   agpt = NULL; }
 545                 if (aptes) { kfree(aptes); aptes = NULL; }
 546                 if (!good_agpt) {
 547                         printk(KERN_WARNING
 548                                "Alternate GPT is invalid, "
 549                                "using primary GPT.\n");
 550                 }
 551                 return 1;
 552         }
 553         else if (good_agpt && (good_pmbr || force_gpt)) {
 554                 *gpt  = agpt;
 555                 *ptes = aptes;
 556                 if (pgpt)  { kfree(pgpt);   pgpt = NULL; }
 557                 if (pptes) { kfree(pptes); pptes = NULL; }
 558                 printk(KERN_WARNING
 559                        "Primary GPT is invalid, using alternate GPT.\n");
 560                 return 1;
 561         }
 562
 563  fail:
 564         if (pgpt)  { kfree(pgpt);   pgpt=NULL; }
 565         if (agpt)  { kfree(agpt);   agpt=NULL; }
 566         if (pptes) { kfree(pptes); pptes=NULL; }
 567         if (aptes) { kfree(aptes); aptes=NULL; }
 568         *gpt = NULL;
 569         *ptes = NULL;
 570         return 0;
 571 }
 572
 573 /**
 574  * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 575  * @state
 576  * @bdev
 577  *
 578  * Description: called from check.c, if the disk contains GPT
 579  * partitions, sets up partition entries in the kernel.
 580  *
 581  * If the first block on the disk is a legacy MBR,
 582  * it will get handled by msdos_partition().
 583  * If it's a Protective MBR, we'll handle it here.
 584  *
 585  * We do not create a Linux partition for GPT, but
 586  * only for the actual data partitions.
 587  * Returns:
 588  * -1 if unable to read the partition table
 589  *  0 if this isn't our partition table
 590  *  1 if successful
 591  *
 592  */
 593 int
 594 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
 595 {
 596         gpt_header *gpt = NULL;
 597         gpt_entry *ptes = NULL;
 598         u32 i;
 599
 600         if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
 601                 kfree(gpt);
 602                 kfree(ptes);
 603                 return 0;
 604         }
 605
 606         Dprintk("GUID Partition Table is valid!  Yea!\n");
 607
 608         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 609                 if (!efi_guidcmp(ptes[i].partition_type_guid, NULL_GUID))
 610                         continue;
 611
 612                 put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
 613                                  (le64_to_cpu(ptes[i].ending_lba) -
 614                                   le64_to_cpu(ptes[i].starting_lba) +
 615                                   1));
 616
 617                 /* If there's this is a RAID volume, tell md */
 618                 if (!efi_guidcmp(ptes[i].partition_type_guid,
 619                                  PARTITION_LINUX_RAID_GUID))
 620                         state->parts[i+1].flags = 1;
 621         }
 622         kfree(ptes);
 623         kfree(gpt);
 624         printk("\n");
 625         return 1;
 626 }
 627
 628 /*
 629  * Overrides for Emacs so that we follow Linus's tabbing style.
 630  * Emacs will notice this stuff at the end of the file and automatically
 631  * adjust the settings for this buffer only.  This must remain at the end
 632  * of the file.
 633  * ---------------------------------------------------------------------------
 634  * Local variables:
 635  * c-indent-level: 4
 636  * c-brace-imaginary-offset: 0
 637  * c-brace-offset: -4
 638  * c-argdecl-indent: 4
 639  * c-label-offset: -4
 640  * c-continued-statement-offset: 4
 641  * c-continued-brace-offset: 0
 642  * indent-tabs-mode: nil
 643  * tab-width: 8
 644  * End:
 645  */