1 /************************************************************
2 * EFI GUID Partition Table handling
4 * http://www.uefi.org/specs/
5 * http://www.intel.com/technology/efi/
7 * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
8 * Copyright 2000,2001,2002,2004 Dell Inc.
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.
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.
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
28 * Mon August 5th, 2013 Davidlohr Bueso <davidlohr@hp.com>
29 * - detect hybrid MBRs, tighter pMBR checking & cleanups.
31 * Mon Nov 09 2004 Matt Domsch <Matt_Domsch@dell.com>
32 * - test for valid PMBR and valid PGPT before ever reading
33 * AGPT, allow override with 'gpt' kernel command line option.
34 * - check for first/last_usable_lba outside of size of disk
36 * Tue Mar 26 2002 Matt Domsch <Matt_Domsch@dell.com>
37 * - Ported to 2.5.7-pre1 and 2.5.7-dj2
38 * - Applied patch to avoid fault in alternate header handling
39 * - cleaned up find_valid_gpt
40 * - On-disk structure and copy in memory is *always* LE now -
41 * swab fields as needed
42 * - remove print_gpt_header()
43 * - only use first max_p partition entries, to keep the kernel minor number
44 * and partition numbers tied.
46 * Mon Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
47 * - Removed __PRIPTR_PREFIX - not being used
49 * Mon Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
50 * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
52 * Thu Dec 6 2001 Matt Domsch <Matt_Domsch@dell.com>
53 * - Added compare_gpts().
54 * - moved le_efi_guid_to_cpus() back into this file. GPT is the only
55 * thing that keeps EFI GUIDs on disk.
56 * - Changed gpt structure names and members to be simpler and more Linux-like.
58 * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
59 * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
61 * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
62 * - Changed function comments to DocBook style per Andreas Dilger suggestion.
64 * Mon Oct 08 2001 Matt Domsch <Matt_Domsch@dell.com>
65 * - Change read_lba() to use the page cache per Al Viro's work.
66 * - print u64s properly on all architectures
67 * - fixed debug_printk(), now Dprintk()
69 * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
71 * - made most functions static
72 * - Endianness addition
73 * - remove test for second alternate header, as it's not per spec,
74 * and is unnecessary. There's now a method to read/write the last
75 * sector of an odd-sized disk from user space. No tools have ever
76 * been released which used this code, so it's effectively dead.
77 * - Per Asit Mallick of Intel, added a test for a valid PMBR.
78 * - Added kernel command line option 'gpt' to override valid PMBR test.
80 * Wed Jun 6 2001 Martin Wilck <Martin.Wilck@Fujitsu-Siemens.com>
81 * - added devfs volume UUID support (/dev/volumes/uuids) for
82 * mounting file systems by the partition GUID.
84 * Tue Dec 5 2000 Matt Domsch <Matt_Domsch@dell.com>
85 * - Moved crc32() to linux/lib, added efi_crc32().
87 * Thu Nov 30 2000 Matt Domsch <Matt_Domsch@dell.com>
88 * - Replaced Intel's CRC32 function with an equivalent
89 * non-license-restricted version.
91 * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
92 * - Fixed the last_lba() call to return the proper last block
94 * Thu Oct 12 2000 Matt Domsch <Matt_Domsch@dell.com>
95 * - Thanks to Andries Brouwer for his debugging assistance.
96 * - Code works, detects all the partitions.
98 ************************************************************/
99 #include <linux/crc32.h>
100 #include <linux/ctype.h>
101 #include <linux/math64.h>
102 #include <linux/slab.h>
106 /* This allows a kernel command line option 'gpt' to override
107 * the test for invalid PMBR. Not __initdata because reloading
108 * the partition tables happens after init too.
110 static int force_gpt;
112 force_gpt_fn(char *str)
117 __setup("gpt", force_gpt_fn);
121 * efi_crc32() - EFI version of crc32 function
122 * @buf: buffer to calculate crc32 of
123 * @len - length of buf
125 * Description: Returns EFI-style CRC32 value for @buf
127 * This function uses the little endian Ethernet polynomial
128 * but seeds the function with ~0, and xor's with ~0 at the end.
129 * Note, the EFI Specification, v1.02, has a reference to
130 * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
133 efi_crc32(const void *buf, unsigned long len)
135 return (crc32(~0L, buf, len) ^ ~0L);
139 * last_lba(): return number of last logical block of device
140 * @bdev: block device
142 * Description: Returns last LBA value on success, 0 on error.
143 * This is stored (by sd and ide-geometry) in
144 * the part[0] entry for this disk, and is the number of
145 * physical sectors available on the disk.
147 static u64 last_lba(struct block_device *bdev)
149 if (!bdev || !bdev->bd_inode)
151 return div_u64(bdev->bd_inode->i_size,
152 bdev_logical_block_size(bdev)) - 1ULL;
155 static inline int pmbr_part_valid(gpt_mbr_record *part)
157 if (part->os_type != EFI_PMBR_OSTYPE_EFI_GPT)
160 /* set to 0x00000001 (i.e., the LBA of the GPT Partition Header) */
161 if (le32_to_cpu(part->starting_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA)
164 return GPT_MBR_PROTECTIVE;
170 * is_pmbr_valid(): test Protective MBR for validity
171 * @mbr: pointer to a legacy mbr structure
172 * @total_sectors: amount of sectors in the device
174 * Description: Checks for a valid protective or hybrid
175 * master boot record (MBR). The validity of a pMBR depends
176 * on all of the following properties:
177 * 1) MSDOS signature is in the last two bytes of the MBR
178 * 2) One partition of type 0xEE is found
180 * In addition, a hybrid MBR will have up to three additional
181 * primary partitions, which point to the same space that's
182 * marked out by up to three GPT partitions.
184 * Returns 0 upon invalid MBR, or GPT_MBR_PROTECTIVE or
185 * GPT_MBR_HYBRID depending on the device layout.
187 static int is_pmbr_valid(legacy_mbr *mbr, sector_t total_sectors)
190 int i, part = 0, ret = 0; /* invalid by default */
192 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
195 for (i = 0; i < 4; i++) {
196 ret = pmbr_part_valid(&mbr->partition_record[i]);
197 if (ret == GPT_MBR_PROTECTIVE) {
200 * Ok, we at least know that there's a protective MBR,
201 * now check if there are other partition types for
208 if (ret != GPT_MBR_PROTECTIVE)
211 for (i = 0; i < 4; i++)
212 if ((mbr->partition_record[i].os_type !=
213 EFI_PMBR_OSTYPE_EFI_GPT) &&
214 (mbr->partition_record[i].os_type != 0x00))
215 ret = GPT_MBR_HYBRID;
218 * Protective MBRs take up the lesser of the whole disk
219 * or 2 TiB (32bit LBA), ignoring the rest of the disk.
220 * Some partitioning programs, nonetheless, choose to set
221 * the size to the maximum 32-bit limitation, disregarding
224 * Hybrid MBRs do not necessarily comply with this.
226 * Consider a bad value here to be a warning to support dd'ing
227 * an image from a smaller disk to a larger disk.
229 if (ret == GPT_MBR_PROTECTIVE) {
230 sz = le32_to_cpu(mbr->partition_record[part].size_in_lba);
231 if (sz != (uint32_t) total_sectors - 1 && sz != 0xFFFFFFFF)
232 pr_debug("GPT: mbr size in lba (%u) different than whole disk (%u).\n",
234 total_sectors - 1, 0xFFFFFFFF));
241 * read_lba(): Read bytes from disk, starting at given LBA
247 * Description: Reads @count bytes from @state->bdev into @buffer.
248 * Returns number of bytes read on success, 0 on error.
250 static size_t read_lba(struct parsed_partitions *state,
251 u64 lba, u8 *buffer, size_t count)
253 size_t totalreadcount = 0;
254 struct block_device *bdev = state->bdev;
255 sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
257 if (!buffer || lba > last_lba(bdev))
263 unsigned char *data = read_part_sector(state, n++, §);
268 memcpy(buffer, data, copied);
269 put_dev_sector(sect);
271 totalreadcount +=copied;
274 return totalreadcount;
278 * alloc_read_gpt_entries(): reads partition entries from disk
282 * Description: Returns ptes on success, NULL on error.
283 * Allocates space for PTEs based on information found in @gpt.
284 * Notes: remember to free pte when you're done!
286 static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
295 count = le32_to_cpu(gpt->num_partition_entries) *
296 le32_to_cpu(gpt->sizeof_partition_entry);
299 pte = kmalloc(count, GFP_KERNEL);
303 if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
304 (u8 *) pte, count) < count) {
313 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
315 * @lba is the Logical Block Address of the partition table
317 * Description: returns GPT header on success, NULL on error. Allocates
318 * and fills a GPT header starting at @ from @state->bdev.
319 * Note: remember to free gpt when finished with it.
321 static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
325 unsigned ssz = bdev_logical_block_size(state->bdev);
327 gpt = kmalloc(ssz, GFP_KERNEL);
331 if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {
341 * is_gpt_valid() - tests one GPT header and PTEs for validity
343 * @lba is the logical block address of the GPT header to test
344 * @gpt is a GPT header ptr, filled on return.
345 * @ptes is a PTEs ptr, filled on return.
347 * Description: returns 1 if valid, 0 on error.
348 * If valid, returns pointers to newly allocated GPT header and PTEs.
350 static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
351 gpt_header **gpt, gpt_entry **ptes)
358 if (!(*gpt = alloc_read_gpt_header(state, lba)))
361 /* Check the GUID Partition Table signature */
362 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
363 pr_debug("GUID Partition Table Header signature is wrong:"
365 (unsigned long long)le64_to_cpu((*gpt)->signature),
366 (unsigned long long)GPT_HEADER_SIGNATURE);
370 /* Check the GUID Partition Table header size is too big */
371 if (le32_to_cpu((*gpt)->header_size) >
372 bdev_logical_block_size(state->bdev)) {
373 pr_debug("GUID Partition Table Header size is too large: %u > %u\n",
374 le32_to_cpu((*gpt)->header_size),
375 bdev_logical_block_size(state->bdev));
379 /* Check the GUID Partition Table header size is too small */
380 if (le32_to_cpu((*gpt)->header_size) < sizeof(gpt_header)) {
381 pr_debug("GUID Partition Table Header size is too small: %u < %zu\n",
382 le32_to_cpu((*gpt)->header_size),
387 /* Check the GUID Partition Table CRC */
388 origcrc = le32_to_cpu((*gpt)->header_crc32);
389 (*gpt)->header_crc32 = 0;
390 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
392 if (crc != origcrc) {
393 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
397 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
399 /* Check that the my_lba entry points to the LBA that contains
400 * the GUID Partition Table */
401 if (le64_to_cpu((*gpt)->my_lba) != lba) {
402 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
403 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
404 (unsigned long long)lba);
408 /* Check the first_usable_lba and last_usable_lba are
411 lastlba = last_lba(state->bdev);
412 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
413 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
414 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
415 (unsigned long long)lastlba);
418 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
419 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
420 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
421 (unsigned long long)lastlba);
424 if (le64_to_cpu((*gpt)->last_usable_lba) < le64_to_cpu((*gpt)->first_usable_lba)) {
425 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
426 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
427 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba));
430 /* Check that sizeof_partition_entry has the correct value */
431 if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {
432 pr_debug("GUID Partitition Entry Size check failed.\n");
436 if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
439 /* Check the GUID Partition Entry Array CRC */
440 crc = efi_crc32((const unsigned char *) (*ptes),
441 le32_to_cpu((*gpt)->num_partition_entries) *
442 le32_to_cpu((*gpt)->sizeof_partition_entry));
444 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
445 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
449 /* We're done, all's well */
462 * is_pte_valid() - tests one PTE for validity
463 * @pte is the pte to check
464 * @lastlba is last lba of the disk
466 * Description: returns 1 if valid, 0 on error.
469 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
471 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
472 le64_to_cpu(pte->starting_lba) > lastlba ||
473 le64_to_cpu(pte->ending_lba) > lastlba)
479 * compare_gpts() - Search disk for valid GPT headers and PTEs
480 * @pgpt is the primary GPT header
481 * @agpt is the alternate GPT header
482 * @lastlba is the last LBA number
483 * Description: Returns nothing. Sanity checks pgpt and agpt fields
484 * and prints warnings on discrepancies.
488 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
493 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
494 pr_warn("GPT:Primary header LBA != Alt. header alternate_lba\n");
495 pr_warn("GPT:%lld != %lld\n",
496 (unsigned long long)le64_to_cpu(pgpt->my_lba),
497 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
500 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
501 pr_warn("GPT:Primary header alternate_lba != Alt. header my_lba\n");
502 pr_warn("GPT:%lld != %lld\n",
503 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
504 (unsigned long long)le64_to_cpu(agpt->my_lba));
507 if (le64_to_cpu(pgpt->first_usable_lba) !=
508 le64_to_cpu(agpt->first_usable_lba)) {
509 pr_warn("GPT:first_usable_lbas don't match.\n");
510 pr_warn("GPT:%lld != %lld\n",
511 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
512 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
515 if (le64_to_cpu(pgpt->last_usable_lba) !=
516 le64_to_cpu(agpt->last_usable_lba)) {
517 pr_warn("GPT:last_usable_lbas don't match.\n");
518 pr_warn("GPT:%lld != %lld\n",
519 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
520 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
523 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
524 pr_warn("GPT:disk_guids don't match.\n");
527 if (le32_to_cpu(pgpt->num_partition_entries) !=
528 le32_to_cpu(agpt->num_partition_entries)) {
529 pr_warn("GPT:num_partition_entries don't match: "
531 le32_to_cpu(pgpt->num_partition_entries),
532 le32_to_cpu(agpt->num_partition_entries));
535 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
536 le32_to_cpu(agpt->sizeof_partition_entry)) {
537 pr_warn("GPT:sizeof_partition_entry values don't match: "
539 le32_to_cpu(pgpt->sizeof_partition_entry),
540 le32_to_cpu(agpt->sizeof_partition_entry));
543 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
544 le32_to_cpu(agpt->partition_entry_array_crc32)) {
545 pr_warn("GPT:partition_entry_array_crc32 values don't match: "
547 le32_to_cpu(pgpt->partition_entry_array_crc32),
548 le32_to_cpu(agpt->partition_entry_array_crc32));
551 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
552 pr_warn("GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
553 pr_warn("GPT:%lld != %lld\n",
554 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
555 (unsigned long long)lastlba);
559 if (le64_to_cpu(agpt->my_lba) != lastlba) {
560 pr_warn("GPT:Alternate GPT header not at the end of the disk.\n");
561 pr_warn("GPT:%lld != %lld\n",
562 (unsigned long long)le64_to_cpu(agpt->my_lba),
563 (unsigned long long)lastlba);
568 pr_warn("GPT: Use GNU Parted to correct GPT errors.\n");
573 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
575 * @gpt is a GPT header ptr, filled on return.
576 * @ptes is a PTEs ptr, filled on return.
577 * Description: Returns 1 if valid, 0 on error.
578 * If valid, returns pointers to newly allocated GPT header and PTEs.
579 * Validity depends on PMBR being valid (or being overridden by the
580 * 'gpt' kernel command line option) and finding either the Primary
581 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
582 * valid. If the Primary GPT header is not valid, the Alternate GPT header
583 * is not checked unless the 'gpt' kernel command line option is passed.
584 * This protects against devices which misreport their size, and forces
585 * the user to decide to use the Alternate GPT.
587 static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
590 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
591 gpt_header *pgpt = NULL, *agpt = NULL;
592 gpt_entry *pptes = NULL, *aptes = NULL;
593 legacy_mbr *legacymbr;
594 sector_t total_sectors = i_size_read(state->bdev->bd_inode) >> 9;
600 lastlba = last_lba(state->bdev);
602 /* This will be added to the EFI Spec. per Intel after v1.02. */
603 legacymbr = kzalloc(sizeof(*legacymbr), GFP_KERNEL);
607 read_lba(state, 0, (u8 *)legacymbr, sizeof(*legacymbr));
608 good_pmbr = is_pmbr_valid(legacymbr, total_sectors);
614 pr_debug("Device has a %s MBR\n",
615 good_pmbr == GPT_MBR_PROTECTIVE ?
616 "protective" : "hybrid");
619 good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
622 good_agpt = is_gpt_valid(state,
623 le64_to_cpu(pgpt->alternate_lba),
625 if (!good_agpt && force_gpt)
626 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
628 /* The obviously unsuccessful case */
629 if (!good_pgpt && !good_agpt)
632 compare_gpts(pgpt, agpt, lastlba);
641 pr_warn("Alternate GPT is invalid, using primary GPT.\n");
644 else if (good_agpt) {
649 pr_warn("Primary GPT is invalid, using alternate GPT.\n");
664 * efi_partition(struct parsed_partitions *state)
667 * Description: called from check.c, if the disk contains GPT
668 * partitions, sets up partition entries in the kernel.
670 * If the first block on the disk is a legacy MBR,
671 * it will get handled by msdos_partition().
672 * If it's a Protective MBR, we'll handle it here.
674 * We do not create a Linux partition for GPT, but
675 * only for the actual data partitions.
677 * -1 if unable to read the partition table
678 * 0 if this isn't our partition table
682 int efi_partition(struct parsed_partitions *state)
684 gpt_header *gpt = NULL;
685 gpt_entry *ptes = NULL;
687 unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
689 if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
695 pr_debug("GUID Partition Table is valid! Yea!\n");
697 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
698 struct partition_meta_info *info;
699 unsigned label_count = 0;
701 u64 start = le64_to_cpu(ptes[i].starting_lba);
702 u64 size = le64_to_cpu(ptes[i].ending_lba) -
703 le64_to_cpu(ptes[i].starting_lba) + 1ULL;
705 if (!is_pte_valid(&ptes[i], last_lba(state->bdev)))
708 put_partition(state, i+1, start * ssz, size * ssz);
710 /* If this is a RAID volume, tell md */
711 if (!efi_guidcmp(ptes[i].partition_type_guid, PARTITION_LINUX_RAID_GUID))
712 state->parts[i + 1].flags = ADDPART_FLAG_RAID;
714 info = &state->parts[i + 1].info;
715 efi_guid_unparse(&ptes[i].unique_partition_guid, info->uuid);
717 /* Naively convert UTF16-LE to 7 bits. */
718 label_max = min(sizeof(info->volname) - 1,
719 sizeof(ptes[i].partition_name));
720 info->volname[label_max] = 0;
721 while (label_count < label_max) {
722 u8 c = ptes[i].partition_name[label_count] & 0xff;
723 if (c && !isprint(c))
725 info->volname[label_count] = c;
728 state->parts[i + 1].has_info = true;
732 strlcat(state->pp_buf, "\n", PAGE_SIZE);