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 */ 106static int force_gpt; 107static int __init 108force_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 */ 128static inline u32 129efi_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 */ 143static 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 151static inline int 152pmbr_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 */ 169static int 170is_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 */ 191static 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++, §); 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 */ 227static 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 */ 263static 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 */ 292static 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 */ 382static inline int 383is_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 */ 401static void 402compare_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 */ 508static 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 */ 601int 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 strlcat(state->pp_buf, "\n", PAGE_SIZE); 634 return 1; 635} 636