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
)
189 int i
, part
= 0, ret
= 0; /* invalid by default */
191 if (!mbr
|| le16_to_cpu(mbr
->signature
) != MSDOS_MBR_SIGNATURE
)
194 for (i
= 0; i
< 4; i
++) {
195 ret
= pmbr_part_valid(&mbr
->partition_record
[i
]);
196 if (ret
== GPT_MBR_PROTECTIVE
) {
199 * Ok, we at least know that there's a protective MBR,
200 * now check if there are other partition types for
207 if (ret
!= GPT_MBR_PROTECTIVE
)
210 for (i
= 0; i
< 4; i
++)
211 if ((mbr
->partition_record
[i
].os_type
!=
212 EFI_PMBR_OSTYPE_EFI_GPT
) &&
213 (mbr
->partition_record
[i
].os_type
!= 0x00))
214 ret
= GPT_MBR_HYBRID
;
217 * Protective MBRs take up the lesser of the whole disk
218 * or 2 TiB (32bit LBA), ignoring the rest of the disk.
220 * Hybrid MBRs do not necessarily comply with this.
222 if (ret
== GPT_MBR_PROTECTIVE
) {
223 if (le32_to_cpu(mbr
->partition_record
[part
].size_in_lba
) !=
224 min((uint32_t) total_sectors
- 1, 0xFFFFFFFF))
232 * read_lba(): Read bytes from disk, starting at given LBA
238 * Description: Reads @count bytes from @state->bdev into @buffer.
239 * Returns number of bytes read on success, 0 on error.
241 static size_t read_lba(struct parsed_partitions
*state
,
242 u64 lba
, u8
*buffer
, size_t count
)
244 size_t totalreadcount
= 0;
245 struct block_device
*bdev
= state
->bdev
;
246 sector_t n
= lba
* (bdev_logical_block_size(bdev
) / 512);
248 if (!buffer
|| lba
> last_lba(bdev
))
254 unsigned char *data
= read_part_sector(state
, n
++, §
);
259 memcpy(buffer
, data
, copied
);
260 put_dev_sector(sect
);
262 totalreadcount
+=copied
;
265 return totalreadcount
;
269 * alloc_read_gpt_entries(): reads partition entries from disk
273 * Description: Returns ptes on success, NULL on error.
274 * Allocates space for PTEs based on information found in @gpt.
275 * Notes: remember to free pte when you're done!
277 static gpt_entry
*alloc_read_gpt_entries(struct parsed_partitions
*state
,
286 count
= le32_to_cpu(gpt
->num_partition_entries
) *
287 le32_to_cpu(gpt
->sizeof_partition_entry
);
290 pte
= kmalloc(count
, GFP_KERNEL
);
294 if (read_lba(state
, le64_to_cpu(gpt
->partition_entry_lba
),
295 (u8
*) pte
, count
) < count
) {
304 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
306 * @lba is the Logical Block Address of the partition table
308 * Description: returns GPT header on success, NULL on error. Allocates
309 * and fills a GPT header starting at @ from @state->bdev.
310 * Note: remember to free gpt when finished with it.
312 static gpt_header
*alloc_read_gpt_header(struct parsed_partitions
*state
,
316 unsigned ssz
= bdev_logical_block_size(state
->bdev
);
318 gpt
= kmalloc(ssz
, GFP_KERNEL
);
322 if (read_lba(state
, lba
, (u8
*) gpt
, ssz
) < ssz
) {
332 * is_gpt_valid() - tests one GPT header and PTEs for validity
334 * @lba is the logical block address of the GPT header to test
335 * @gpt is a GPT header ptr, filled on return.
336 * @ptes is a PTEs ptr, filled on return.
338 * Description: returns 1 if valid, 0 on error.
339 * If valid, returns pointers to newly allocated GPT header and PTEs.
341 static int is_gpt_valid(struct parsed_partitions
*state
, u64 lba
,
342 gpt_header
**gpt
, gpt_entry
**ptes
)
349 if (!(*gpt
= alloc_read_gpt_header(state
, lba
)))
352 /* Check the GUID Partition Table signature */
353 if (le64_to_cpu((*gpt
)->signature
) != GPT_HEADER_SIGNATURE
) {
354 pr_debug("GUID Partition Table Header signature is wrong:"
356 (unsigned long long)le64_to_cpu((*gpt
)->signature
),
357 (unsigned long long)GPT_HEADER_SIGNATURE
);
361 /* Check the GUID Partition Table header size is too big */
362 if (le32_to_cpu((*gpt
)->header_size
) >
363 bdev_logical_block_size(state
->bdev
)) {
364 pr_debug("GUID Partition Table Header size is too large: %u > %u\n",
365 le32_to_cpu((*gpt
)->header_size
),
366 bdev_logical_block_size(state
->bdev
));
370 /* Check the GUID Partition Table header size is too small */
371 if (le32_to_cpu((*gpt
)->header_size
) < sizeof(gpt_header
)) {
372 pr_debug("GUID Partition Table Header size is too small: %u < %zu\n",
373 le32_to_cpu((*gpt
)->header_size
),
378 /* Check the GUID Partition Table CRC */
379 origcrc
= le32_to_cpu((*gpt
)->header_crc32
);
380 (*gpt
)->header_crc32
= 0;
381 crc
= efi_crc32((const unsigned char *) (*gpt
), le32_to_cpu((*gpt
)->header_size
));
383 if (crc
!= origcrc
) {
384 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
388 (*gpt
)->header_crc32
= cpu_to_le32(origcrc
);
390 /* Check that the my_lba entry points to the LBA that contains
391 * the GUID Partition Table */
392 if (le64_to_cpu((*gpt
)->my_lba
) != lba
) {
393 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
394 (unsigned long long)le64_to_cpu((*gpt
)->my_lba
),
395 (unsigned long long)lba
);
399 /* Check the first_usable_lba and last_usable_lba are
402 lastlba
= last_lba(state
->bdev
);
403 if (le64_to_cpu((*gpt
)->first_usable_lba
) > lastlba
) {
404 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
405 (unsigned long long)le64_to_cpu((*gpt
)->first_usable_lba
),
406 (unsigned long long)lastlba
);
409 if (le64_to_cpu((*gpt
)->last_usable_lba
) > lastlba
) {
410 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
411 (unsigned long long)le64_to_cpu((*gpt
)->last_usable_lba
),
412 (unsigned long long)lastlba
);
415 if (le64_to_cpu((*gpt
)->last_usable_lba
) < le64_to_cpu((*gpt
)->first_usable_lba
)) {
416 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
417 (unsigned long long)le64_to_cpu((*gpt
)->last_usable_lba
),
418 (unsigned long long)le64_to_cpu((*gpt
)->first_usable_lba
));
421 /* Check that sizeof_partition_entry has the correct value */
422 if (le32_to_cpu((*gpt
)->sizeof_partition_entry
) != sizeof(gpt_entry
)) {
423 pr_debug("GUID Partitition Entry Size check failed.\n");
427 if (!(*ptes
= alloc_read_gpt_entries(state
, *gpt
)))
430 /* Check the GUID Partition Entry Array CRC */
431 crc
= efi_crc32((const unsigned char *) (*ptes
),
432 le32_to_cpu((*gpt
)->num_partition_entries
) *
433 le32_to_cpu((*gpt
)->sizeof_partition_entry
));
435 if (crc
!= le32_to_cpu((*gpt
)->partition_entry_array_crc32
)) {
436 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
440 /* We're done, all's well */
453 * is_pte_valid() - tests one PTE for validity
454 * @pte is the pte to check
455 * @lastlba is last lba of the disk
457 * Description: returns 1 if valid, 0 on error.
460 is_pte_valid(const gpt_entry
*pte
, const u64 lastlba
)
462 if ((!efi_guidcmp(pte
->partition_type_guid
, NULL_GUID
)) ||
463 le64_to_cpu(pte
->starting_lba
) > lastlba
||
464 le64_to_cpu(pte
->ending_lba
) > lastlba
)
470 * compare_gpts() - Search disk for valid GPT headers and PTEs
471 * @pgpt is the primary GPT header
472 * @agpt is the alternate GPT header
473 * @lastlba is the last LBA number
474 * Description: Returns nothing. Sanity checks pgpt and agpt fields
475 * and prints warnings on discrepancies.
479 compare_gpts(gpt_header
*pgpt
, gpt_header
*agpt
, u64 lastlba
)
484 if (le64_to_cpu(pgpt
->my_lba
) != le64_to_cpu(agpt
->alternate_lba
)) {
485 pr_warn("GPT:Primary header LBA != Alt. header alternate_lba\n");
486 pr_warn("GPT:%lld != %lld\n",
487 (unsigned long long)le64_to_cpu(pgpt
->my_lba
),
488 (unsigned long long)le64_to_cpu(agpt
->alternate_lba
));
491 if (le64_to_cpu(pgpt
->alternate_lba
) != le64_to_cpu(agpt
->my_lba
)) {
492 pr_warn("GPT:Primary header alternate_lba != Alt. header my_lba\n");
493 pr_warn("GPT:%lld != %lld\n",
494 (unsigned long long)le64_to_cpu(pgpt
->alternate_lba
),
495 (unsigned long long)le64_to_cpu(agpt
->my_lba
));
498 if (le64_to_cpu(pgpt
->first_usable_lba
) !=
499 le64_to_cpu(agpt
->first_usable_lba
)) {
500 pr_warn("GPT:first_usable_lbas don't match.\n");
501 pr_warn("GPT:%lld != %lld\n",
502 (unsigned long long)le64_to_cpu(pgpt
->first_usable_lba
),
503 (unsigned long long)le64_to_cpu(agpt
->first_usable_lba
));
506 if (le64_to_cpu(pgpt
->last_usable_lba
) !=
507 le64_to_cpu(agpt
->last_usable_lba
)) {
508 pr_warn("GPT:last_usable_lbas don't match.\n");
509 pr_warn("GPT:%lld != %lld\n",
510 (unsigned long long)le64_to_cpu(pgpt
->last_usable_lba
),
511 (unsigned long long)le64_to_cpu(agpt
->last_usable_lba
));
514 if (efi_guidcmp(pgpt
->disk_guid
, agpt
->disk_guid
)) {
515 pr_warn("GPT:disk_guids don't match.\n");
518 if (le32_to_cpu(pgpt
->num_partition_entries
) !=
519 le32_to_cpu(agpt
->num_partition_entries
)) {
520 pr_warn("GPT:num_partition_entries don't match: "
522 le32_to_cpu(pgpt
->num_partition_entries
),
523 le32_to_cpu(agpt
->num_partition_entries
));
526 if (le32_to_cpu(pgpt
->sizeof_partition_entry
) !=
527 le32_to_cpu(agpt
->sizeof_partition_entry
)) {
528 pr_warn("GPT:sizeof_partition_entry values don't match: "
530 le32_to_cpu(pgpt
->sizeof_partition_entry
),
531 le32_to_cpu(agpt
->sizeof_partition_entry
));
534 if (le32_to_cpu(pgpt
->partition_entry_array_crc32
) !=
535 le32_to_cpu(agpt
->partition_entry_array_crc32
)) {
536 pr_warn("GPT:partition_entry_array_crc32 values don't match: "
538 le32_to_cpu(pgpt
->partition_entry_array_crc32
),
539 le32_to_cpu(agpt
->partition_entry_array_crc32
));
542 if (le64_to_cpu(pgpt
->alternate_lba
) != lastlba
) {
543 pr_warn("GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
544 pr_warn("GPT:%lld != %lld\n",
545 (unsigned long long)le64_to_cpu(pgpt
->alternate_lba
),
546 (unsigned long long)lastlba
);
550 if (le64_to_cpu(agpt
->my_lba
) != lastlba
) {
551 pr_warn("GPT:Alternate GPT header not at the end of the disk.\n");
552 pr_warn("GPT:%lld != %lld\n",
553 (unsigned long long)le64_to_cpu(agpt
->my_lba
),
554 (unsigned long long)lastlba
);
559 pr_warn("GPT: Use GNU Parted to correct GPT errors.\n");
564 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
566 * @gpt is a GPT header ptr, filled on return.
567 * @ptes is a PTEs ptr, filled on return.
568 * Description: Returns 1 if valid, 0 on error.
569 * If valid, returns pointers to newly allocated GPT header and PTEs.
570 * Validity depends on PMBR being valid (or being overridden by the
571 * 'gpt' kernel command line option) and finding either the Primary
572 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
573 * valid. If the Primary GPT header is not valid, the Alternate GPT header
574 * is not checked unless the 'gpt' kernel command line option is passed.
575 * This protects against devices which misreport their size, and forces
576 * the user to decide to use the Alternate GPT.
578 static int find_valid_gpt(struct parsed_partitions
*state
, gpt_header
**gpt
,
581 int good_pgpt
= 0, good_agpt
= 0, good_pmbr
= 0;
582 gpt_header
*pgpt
= NULL
, *agpt
= NULL
;
583 gpt_entry
*pptes
= NULL
, *aptes
= NULL
;
584 legacy_mbr
*legacymbr
;
585 sector_t total_sectors
= i_size_read(state
->bdev
->bd_inode
) >> 9;
591 lastlba
= last_lba(state
->bdev
);
593 /* This will be added to the EFI Spec. per Intel after v1.02. */
594 legacymbr
= kzalloc(sizeof(*legacymbr
), GFP_KERNEL
);
598 read_lba(state
, 0, (u8
*)legacymbr
, sizeof(*legacymbr
));
599 good_pmbr
= is_pmbr_valid(legacymbr
, total_sectors
);
605 pr_debug("Device has a %s MBR\n",
606 good_pmbr
== GPT_MBR_PROTECTIVE
?
607 "protective" : "hybrid");
610 good_pgpt
= is_gpt_valid(state
, GPT_PRIMARY_PARTITION_TABLE_LBA
,
613 good_agpt
= is_gpt_valid(state
,
614 le64_to_cpu(pgpt
->alternate_lba
),
616 if (!good_agpt
&& force_gpt
)
617 good_agpt
= is_gpt_valid(state
, lastlba
, &agpt
, &aptes
);
619 /* The obviously unsuccessful case */
620 if (!good_pgpt
&& !good_agpt
)
623 compare_gpts(pgpt
, agpt
, lastlba
);
632 pr_warn("Alternate GPT is invalid, using primary GPT.\n");
635 else if (good_agpt
) {
640 pr_warn("Primary GPT is invalid, using alternate GPT.\n");
655 * efi_partition(struct parsed_partitions *state)
658 * Description: called from check.c, if the disk contains GPT
659 * partitions, sets up partition entries in the kernel.
661 * If the first block on the disk is a legacy MBR,
662 * it will get handled by msdos_partition().
663 * If it's a Protective MBR, we'll handle it here.
665 * We do not create a Linux partition for GPT, but
666 * only for the actual data partitions.
668 * -1 if unable to read the partition table
669 * 0 if this isn't our partition table
673 int efi_partition(struct parsed_partitions
*state
)
675 gpt_header
*gpt
= NULL
;
676 gpt_entry
*ptes
= NULL
;
678 unsigned ssz
= bdev_logical_block_size(state
->bdev
) / 512;
680 if (!find_valid_gpt(state
, &gpt
, &ptes
) || !gpt
|| !ptes
) {
686 pr_debug("GUID Partition Table is valid! Yea!\n");
688 for (i
= 0; i
< le32_to_cpu(gpt
->num_partition_entries
) && i
< state
->limit
-1; i
++) {
689 struct partition_meta_info
*info
;
690 unsigned label_count
= 0;
692 u64 start
= le64_to_cpu(ptes
[i
].starting_lba
);
693 u64 size
= le64_to_cpu(ptes
[i
].ending_lba
) -
694 le64_to_cpu(ptes
[i
].starting_lba
) + 1ULL;
696 if (!is_pte_valid(&ptes
[i
], last_lba(state
->bdev
)))
699 put_partition(state
, i
+1, start
* ssz
, size
* ssz
);
701 /* If this is a RAID volume, tell md */
702 if (!efi_guidcmp(ptes
[i
].partition_type_guid
, PARTITION_LINUX_RAID_GUID
))
703 state
->parts
[i
+ 1].flags
= ADDPART_FLAG_RAID
;
705 info
= &state
->parts
[i
+ 1].info
;
706 efi_guid_unparse(&ptes
[i
].unique_partition_guid
, info
->uuid
);
708 /* Naively convert UTF16-LE to 7 bits. */
709 label_max
= min(sizeof(info
->volname
) - 1,
710 sizeof(ptes
[i
].partition_name
));
711 info
->volname
[label_max
] = 0;
712 while (label_count
< label_max
) {
713 u8 c
= ptes
[i
].partition_name
[label_count
] & 0xff;
714 if (c
&& !isprint(c
))
716 info
->volname
[label_count
] = c
;
719 state
->parts
[i
+ 1].has_info
= true;
723 strlcat(state
->pp_buf
, "\n", PAGE_SIZE
);