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