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/ctype.h>
  98 #include <linux/math64.h>
  99 #include <linux/slab.h>
 100 #include "check.h"
 101 #include "efi.h"
 102
 103 /* This allows a kernel command line option 'gpt' to override
 104  * the test for invalid PMBR.  Not __initdata because reloading
 105  * the partition tables happens after init too.
 106  */
 107 static int force_gpt;
 108 static int __init
 109 force_gpt_fn(char *str)
 110 {
 111         force_gpt = 1;
 112         return 1;
 113 }
 114 __setup("gpt", force_gpt_fn);
 115
 116
 117 /**
 118  * efi_crc32() - EFI version of crc32 function
 119  * @buf: buffer to calculate crc32 of
 120  * @len - length of buf
 121  *
 122  * Description: Returns EFI-style CRC32 value for @buf
 123  *
 124  * This function uses the little endian Ethernet polynomial
 125  * but seeds the function with ~0, and xor's with ~0 at the end.
 126  * Note, the EFI Specification, v1.02, has a reference to
 127  * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
 128  */
 129 static inline u32
 130 efi_crc32(const void *buf, unsigned long len)
 131 {
 132         return (crc32(~0L, buf, len) ^ ~0L);
 133 }
 134
 135 /**
 136  * last_lba(): return number of last logical block of device
 137  * @bdev: block device
 138  *
 139  * Description: Returns last LBA value on success, 0 on error.
 140  * This is stored (by sd and ide-geometry) in
 141  *  the part[0] entry for this disk, and is the number of
 142  *  physical sectors available on the disk.
 143  */
 144 static u64 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  * @state
 185  * @lba
 186  * @buffer
 187  * @size_t
 188  *
 189  * Description: Reads @count bytes from @state->bdev into @buffer.
 190  * Returns number of bytes read on success, 0 on error.
 191  */
 192 static size_t read_lba(struct parsed_partitions *state,
 193                        u64 lba, u8 *buffer, size_t count)
 194 {
 195         size_t totalreadcount = 0;
 196         struct block_device *bdev = state->bdev;
 197         sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
 198
 199         if (!buffer || lba > last_lba(bdev))
 200                 return 0;
 201
 202         while (count) {
 203                 int copied = 512;
 204                 Sector sect;
 205                 unsigned char *data = read_part_sector(state, n++, &sect);
 206                 if (!data)
 207                         break;
 208                 if (copied > count)
 209                         copied = count;
 210                 memcpy(buffer, data, copied);
 211                 put_dev_sector(sect);
 212                 buffer += copied;
 213                 totalreadcount +=copied;
 214                 count -= copied;
 215         }
 216         return totalreadcount;
 217 }
 218
 219 /**
 220  * alloc_read_gpt_entries(): reads partition entries from disk
 221  * @state
 222  * @gpt - GPT header
 223  *
 224  * Description: Returns ptes on success,  NULL on error.
 225  * Allocates space for PTEs based on information found in @gpt.
 226  * Notes: remember to free pte when you're done!
 227  */
 228 static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
 229                                          gpt_header *gpt)
 230 {
 231         size_t count;
 232         gpt_entry *pte;
 233
 234         if (!gpt)
 235                 return NULL;
 236
 237         count = le32_to_cpu(gpt->num_partition_entries) *
 238                 le32_to_cpu(gpt->sizeof_partition_entry);
 239         if (!count)
 240                 return NULL;
 241         pte = kzalloc(count, GFP_KERNEL);
 242         if (!pte)
 243                 return NULL;
 244
 245         if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
 246                      (u8 *) pte,
 247                      count) < count) {
 248                 kfree(pte);
 249                 pte=NULL;
 250                 return NULL;
 251         }
 252         return pte;
 253 }
 254
 255 /**
 256  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
 257  * @state
 258  * @lba is the Logical Block Address of the partition table
 259  *
 260  * Description: returns GPT header on success, NULL on error.   Allocates
 261  * and fills a GPT header starting at @ from @state->bdev.
 262  * Note: remember to free gpt when finished with it.
 263  */
 264 static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
 265                                          u64 lba)
 266 {
 267         gpt_header *gpt;
 268         unsigned ssz = bdev_logical_block_size(state->bdev);
 269
 270         gpt = kzalloc(ssz, GFP_KERNEL);
 271         if (!gpt)
 272                 return NULL;
 273
 274         if (read_lba(state, 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  * @state
 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 is_gpt_valid(struct parsed_partitions *state, u64 lba,
 294                         gpt_header **gpt, gpt_entry **ptes)
 295 {
 296         u32 crc, origcrc;
 297         u64 lastlba;
 298
 299         if (!ptes)
 300                 return 0;
 301         if (!(*gpt = alloc_read_gpt_header(state, lba)))
 302                 return 0;
 303
 304         /* Check the GUID Partition Table signature */
 305         if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
 306                 pr_debug("GUID Partition Table Header signature is wrong:"
 307                          "%lld != %lld\n",
 308                          (unsigned long long)le64_to_cpu((*gpt)->signature),
 309                          (unsigned long long)GPT_HEADER_SIGNATURE);
 310                 goto fail;
 311         }
 312
 313         /* Check the GUID Partition Table CRC */
 314         origcrc = le32_to_cpu((*gpt)->header_crc32);
 315         (*gpt)->header_crc32 = 0;
 316         crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
 317
 318         if (crc != origcrc) {
 319                 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
 320                          crc, origcrc);
 321                 goto fail;
 322         }
 323         (*gpt)->header_crc32 = cpu_to_le32(origcrc);
 324
 325         /* Check that the my_lba entry points to the LBA that contains
 326          * the GUID Partition Table */
 327         if (le64_to_cpu((*gpt)->my_lba) != lba) {
 328                 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
 329                          (unsigned long long)le64_to_cpu((*gpt)->my_lba),
 330                          (unsigned long long)lba);
 331                 goto fail;
 332         }
 333
 334         /* Check the first_usable_lba and last_usable_lba are
 335          * within the disk.
 336          */
 337         lastlba = last_lba(state->bdev);
 338         if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
 339                 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
 340                          (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
 341                          (unsigned long long)lastlba);
 342                 goto fail;
 343         }
 344         if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
 345                 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
 346                          (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
 347                          (unsigned long long)lastlba);
 348                 goto fail;
 349         }
 350
 351         if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
 352                 goto fail;
 353
 354         /* Check the GUID Partition Entry Array CRC */
 355         crc = efi_crc32((const unsigned char *) (*ptes),
 356                         le32_to_cpu((*gpt)->num_partition_entries) *
 357                         le32_to_cpu((*gpt)->sizeof_partition_entry));
 358
 359         if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
 360                 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
 361                 goto fail_ptes;
 362         }
 363
 364         /* We're done, all's well */
 365         return 1;
 366
 367  fail_ptes:
 368         kfree(*ptes);
 369         *ptes = NULL;
 370  fail:
 371         kfree(*gpt);
 372         *gpt = NULL;
 373         return 0;
 374 }
 375
 376 /**
 377  * is_pte_valid() - tests one PTE for validity
 378  * @pte is the pte to check
 379  * @lastlba is last lba of the disk
 380  *
 381  * Description: returns 1 if valid,  0 on error.
 382  */
 383 static inline int
 384 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
 385 {
 386         if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
 387             le64_to_cpu(pte->starting_lba) > lastlba         ||
 388             le64_to_cpu(pte->ending_lba)   > lastlba)
 389                 return 0;
 390         return 1;
 391 }
 392
 393 /**
 394  * compare_gpts() - Search disk for valid GPT headers and PTEs
 395  * @pgpt is the primary GPT header
 396  * @agpt is the alternate GPT header
 397  * @lastlba is the last LBA number
 398  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
 399  * and prints warnings on discrepancies.
 400  *
 401  */
 402 static void
 403 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
 404 {
 405         int error_found = 0;
 406         if (!pgpt || !agpt)
 407                 return;
 408         if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
 409                 printk(KERN_WARNING
 410                        "GPT:Primary header LBA != Alt. header alternate_lba\n");
 411                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 412                        (unsigned long long)le64_to_cpu(pgpt->my_lba),
 413                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
 414                 error_found++;
 415         }
 416         if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
 417                 printk(KERN_WARNING
 418                        "GPT:Primary header alternate_lba != Alt. header my_lba\n");
 419                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 420                        (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 421                        (unsigned long long)le64_to_cpu(agpt->my_lba));
 422                 error_found++;
 423         }
 424         if (le64_to_cpu(pgpt->first_usable_lba) !=
 425             le64_to_cpu(agpt->first_usable_lba)) {
 426                 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
 427                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 428                        (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
 429                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
 430                 error_found++;
 431         }
 432         if (le64_to_cpu(pgpt->last_usable_lba) !=
 433             le64_to_cpu(agpt->last_usable_lba)) {
 434                 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
 435                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 436                        (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
 437                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
 438                 error_found++;
 439         }
 440         if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
 441                 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
 442                 error_found++;
 443         }
 444         if (le32_to_cpu(pgpt->num_partition_entries) !=
 445             le32_to_cpu(agpt->num_partition_entries)) {
 446                 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
 447                        "0x%x != 0x%x\n",
 448                        le32_to_cpu(pgpt->num_partition_entries),
 449                        le32_to_cpu(agpt->num_partition_entries));
 450                 error_found++;
 451         }
 452         if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
 453             le32_to_cpu(agpt->sizeof_partition_entry)) {
 454                 printk(KERN_WARNING
 455                        "GPT:sizeof_partition_entry values don't match: "
 456                        "0x%x != 0x%x\n",
 457                        le32_to_cpu(pgpt->sizeof_partition_entry),
 458                        le32_to_cpu(agpt->sizeof_partition_entry));
 459                 error_found++;
 460         }
 461         if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
 462             le32_to_cpu(agpt->partition_entry_array_crc32)) {
 463                 printk(KERN_WARNING
 464                        "GPT:partition_entry_array_crc32 values don't match: "
 465                        "0x%x != 0x%x\n",
 466                        le32_to_cpu(pgpt->partition_entry_array_crc32),
 467                        le32_to_cpu(agpt->partition_entry_array_crc32));
 468                 error_found++;
 469         }
 470         if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
 471                 printk(KERN_WARNING
 472                        "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
 473                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 474                         (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
 475                         (unsigned long long)lastlba);
 476                 error_found++;
 477         }
 478
 479         if (le64_to_cpu(agpt->my_lba) != lastlba) {
 480                 printk(KERN_WARNING
 481                        "GPT:Alternate GPT header not at the end of the disk.\n");
 482                 printk(KERN_WARNING "GPT:%lld != %lld\n",
 483                         (unsigned long long)le64_to_cpu(agpt->my_lba),
 484                         (unsigned long long)lastlba);
 485                 error_found++;
 486         }
 487
 488         if (error_found)
 489                 printk(KERN_WARNING
 490                        "GPT: Use GNU Parted to correct GPT errors.\n");
 491         return;
 492 }
 493
 494 /**
 495  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
 496  * @state
 497  * @gpt is a GPT header ptr, filled on return.
 498  * @ptes is a PTEs ptr, filled on return.
 499  * Description: Returns 1 if valid, 0 on error.
 500  * If valid, returns pointers to newly allocated GPT header and PTEs.
 501  * Validity depends on PMBR being valid (or being overridden by the
 502  * 'gpt' kernel command line option) and finding either the Primary
 503  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
 504  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
 505  * is not checked unless the 'gpt' kernel command line option is passed.
 506  * This protects against devices which misreport their size, and forces
 507  * the user to decide to use the Alternate GPT.
 508  */
 509 static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
 510                           gpt_entry **ptes)
 511 {
 512         int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
 513         gpt_header *pgpt = NULL, *agpt = NULL;
 514         gpt_entry *pptes = NULL, *aptes = NULL;
 515         legacy_mbr *legacymbr;
 516         u64 lastlba;
 517
 518         if (!ptes)
 519                 return 0;
 520
 521         lastlba = last_lba(state->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(state, 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(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
 536                                  &pgpt, &pptes);
 537         if (good_pgpt)
 538                 good_agpt = is_gpt_valid(state,
 539                                          le64_to_cpu(pgpt->alternate_lba),
 540                                          &agpt, &aptes);
 541         if (!good_agpt && force_gpt)
 542                 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
 543
 544         /* The obviously unsuccessful case */
 545         if (!good_pgpt && !good_agpt)
 546                 goto fail;
 547
 548         compare_gpts(pgpt, agpt, lastlba);
 549
 550         /* The good cases */
 551         if (good_pgpt) {
 552                 *gpt  = pgpt;
 553                 *ptes = pptes;
 554                 kfree(agpt);
 555                 kfree(aptes);
 556                 if (!good_agpt) {
 557                         printk(KERN_WARNING
 558                                "Alternate GPT is invalid, "
 559                                "using primary GPT.\n");
 560                 }
 561                 return 1;
 562         }
 563         else if (good_agpt) {
 564                 *gpt  = agpt;
 565                 *ptes = aptes;
 566                 kfree(pgpt);
 567                 kfree(pptes);
 568                 printk(KERN_WARNING
 569                        "Primary GPT is invalid, using alternate GPT.\n");
 570                 return 1;
 571         }
 572
 573  fail:
 574         kfree(pgpt);
 575         kfree(agpt);
 576         kfree(pptes);
 577         kfree(aptes);
 578         *gpt = NULL;
 579         *ptes = NULL;
 580         return 0;
 581 }
 582
 583 /**
 584  * efi_partition(struct parsed_partitions *state)
 585  * @state
 586  *
 587  * Description: called from check.c, if the disk contains GPT
 588  * partitions, sets up partition entries in the kernel.
 589  *
 590  * If the first block on the disk is a legacy MBR,
 591  * it will get handled by msdos_partition().
 592  * If it's a Protective MBR, we'll handle it here.
 593  *
 594  * We do not create a Linux partition for GPT, but
 595  * only for the actual data partitions.
 596  * Returns:
 597  * -1 if unable to read the partition table
 598  *  0 if this isn't our partition table
 599  *  1 if successful
 600  *
 601  */
 602 int efi_partition(struct parsed_partitions *state)
 603 {
 604         gpt_header *gpt = NULL;
 605         gpt_entry *ptes = NULL;
 606         u32 i;
 607         unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
 608         u8 unparsed_guid[37];
 609
 610         if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
 611                 kfree(gpt);
 612                 kfree(ptes);
 613                 return 0;
 614         }
 615
 616         pr_debug("GUID Partition Table is valid!  Yea!\n");
 617
 618         for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
 619                 struct partition_meta_info *info;
 620                 unsigned label_count = 0;
 621                 unsigned label_max;
 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(state->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 = ADDPART_FLAG_RAID;
 635
 636                 info = &state->parts[i + 1].info;
 637                 /* Instead of doing a manual swap to big endian, reuse the
 638                  * common ASCII hex format as the interim.
 639                  */
 640                 efi_guid_unparse(&ptes[i].unique_partition_guid, unparsed_guid);
 641                 part_pack_uuid(unparsed_guid, info->uuid);
 642
 643                 /* Naively convert UTF16-LE to 7 bits. */
 644                 label_max = min(sizeof(info->volname) - 1,
 645                                 sizeof(ptes[i].partition_name));
 646                 info->volname[label_max] = 0;
 647                 while (label_count < label_max) {
 648                         u8 c = ptes[i].partition_name[label_count] & 0xff;
 649                         if (c && !isprint(c))
 650                                 c = '!';
 651                         info->volname[label_count] = c;
 652                         label_count++;
 653                 }
 654                 state->parts[i + 1].has_info = true;
 655         }
 656         kfree(ptes);
 657         kfree(gpt);
 658         strlcat(state->pp_buf, "\n", PAGE_SIZE);
 659         return 1;
 660 }