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 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
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.
43 * Mon Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
44 * - Removed __PRIPTR_PREFIX - not being used
46 * Mon Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
47 * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
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.
55 * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
56 * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
58 * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
59 * - Changed function comments to DocBook style per Andreas Dilger suggestion.
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()
66 * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
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.
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.
81 * Tue Dec 5 2000 Matt Domsch <Matt_Domsch@dell.com>
82 * - Moved crc32() to linux/lib, added efi_crc32().
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.
88 * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
89 * - Fixed the last_lba() call to return the proper last block
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.
95 ************************************************************/
96 #include <linux/crc32.h>
97 #include <linux/ctype.h>
98 #include <linux/math64.h>
99 #include <linux/slab.h>
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.
107 static int force_gpt;
109 force_gpt_fn(char *str)
114 __setup("gpt", force_gpt_fn);
118 * efi_crc32() - EFI version of crc32 function
119 * @buf: buffer to calculate crc32 of
120 * @len - length of buf
122 * Description: Returns EFI-style CRC32 value for @buf
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).
130 efi_crc32(const void *buf, unsigned long len)
132 return (crc32(~0L, buf, len) ^ ~0L);
136 * last_lba(): return number of last logical block of device
137 * @bdev: block device
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.
144 static u64 last_lba(struct block_device *bdev)
146 if (!bdev || !bdev->bd_inode)
148 return div_u64(bdev->bd_inode->i_size,
149 bdev_logical_block_size(bdev)) - 1ULL;
152 static inline int pmbr_part_valid(gpt_mbr_record *part)
154 if (part->os_type != EFI_PMBR_OSTYPE_EFI_GPT)
157 /* set to 0x00000001 (i.e., the LBA of the GPT Partition Header) */
158 if (le32_to_cpu(part->starting_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA)
161 return GPT_MBR_PROTECTIVE;
167 * is_pmbr_valid(): test Protective MBR for validity
168 * @mbr: pointer to a legacy mbr structure
170 * Description: Checks for a valid protective or hybrid
171 * master boot record (MBR). The validity of a pMBR depends
172 * on all of the following properties:
173 * 1) MSDOS signature is in the last two bytes of the MBR
174 * 2) One partition of type 0xEE is found
176 * In addition, a hybrid MBR will have up to three additional
177 * primary partitions, which point to the same space that's
178 * marked out by up to three GPT partitions.
180 * Returns 0 upon invalid MBR, or GPT_MBR_PROTECTIVE or
181 * GPT_MBR_HYBRID depending on the device layout.
183 static int is_pmbr_valid(legacy_mbr *mbr)
185 int i, ret = 0; /* invalid by default */
187 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
190 for (i = 0; i < 4; i++) {
191 ret = pmbr_part_valid(&mbr->partition_record[i]);
192 if (ret == GPT_MBR_PROTECTIVE) {
194 * Ok, we at least know that there's a protective MBR,
195 * now check if there are other partition types for
202 if (ret != GPT_MBR_PROTECTIVE)
205 for (i = 0; i < 4; i++)
206 if ((mbr->partition_record[i].os_type !=
207 EFI_PMBR_OSTYPE_EFI_GPT) &&
208 (mbr->partition_record[i].os_type != 0x00))
209 ret = GPT_MBR_HYBRID;
215 * read_lba(): Read bytes from disk, starting at given LBA
221 * Description: Reads @count bytes from @state->bdev into @buffer.
222 * Returns number of bytes read on success, 0 on error.
224 static size_t read_lba(struct parsed_partitions *state,
225 u64 lba, u8 *buffer, size_t count)
227 size_t totalreadcount = 0;
228 struct block_device *bdev = state->bdev;
229 sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
231 if (!buffer || lba > last_lba(bdev))
237 unsigned char *data = read_part_sector(state, n++, §);
242 memcpy(buffer, data, copied);
243 put_dev_sector(sect);
245 totalreadcount +=copied;
248 return totalreadcount;
252 * alloc_read_gpt_entries(): reads partition entries from disk
256 * Description: Returns ptes on success, NULL on error.
257 * Allocates space for PTEs based on information found in @gpt.
258 * Notes: remember to free pte when you're done!
260 static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
269 count = le32_to_cpu(gpt->num_partition_entries) *
270 le32_to_cpu(gpt->sizeof_partition_entry);
273 pte = kmalloc(count, GFP_KERNEL);
277 if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
288 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
290 * @lba is the Logical Block Address of the partition table
292 * Description: returns GPT header on success, NULL on error. Allocates
293 * and fills a GPT header starting at @ from @state->bdev.
294 * Note: remember to free gpt when finished with it.
296 static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
300 unsigned ssz = bdev_logical_block_size(state->bdev);
302 gpt = kmalloc(ssz, GFP_KERNEL);
306 if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {
316 * is_gpt_valid() - tests one GPT header and PTEs for validity
318 * @lba is the logical block address of the GPT header to test
319 * @gpt is a GPT header ptr, filled on return.
320 * @ptes is a PTEs ptr, filled on return.
322 * Description: returns 1 if valid, 0 on error.
323 * If valid, returns pointers to newly allocated GPT header and PTEs.
325 static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
326 gpt_header **gpt, gpt_entry **ptes)
333 if (!(*gpt = alloc_read_gpt_header(state, lba)))
336 /* Check the GUID Partition Table signature */
337 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
338 pr_debug("GUID Partition Table Header signature is wrong:"
340 (unsigned long long)le64_to_cpu((*gpt)->signature),
341 (unsigned long long)GPT_HEADER_SIGNATURE);
345 /* Check the GUID Partition Table header size is too big */
346 if (le32_to_cpu((*gpt)->header_size) >
347 bdev_logical_block_size(state->bdev)) {
348 pr_debug("GUID Partition Table Header size is too large: %u > %u\n",
349 le32_to_cpu((*gpt)->header_size),
350 bdev_logical_block_size(state->bdev));
354 /* Check the GUID Partition Table header size is too small */
355 if (le32_to_cpu((*gpt)->header_size) < sizeof(gpt_header)) {
356 pr_debug("GUID Partition Table Header size is too small: %u < %zu\n",
357 le32_to_cpu((*gpt)->header_size),
362 /* Check the GUID Partition Table CRC */
363 origcrc = le32_to_cpu((*gpt)->header_crc32);
364 (*gpt)->header_crc32 = 0;
365 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
367 if (crc != origcrc) {
368 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
372 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
374 /* Check that the my_lba entry points to the LBA that contains
375 * the GUID Partition Table */
376 if (le64_to_cpu((*gpt)->my_lba) != lba) {
377 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
378 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
379 (unsigned long long)lba);
383 /* Check the first_usable_lba and last_usable_lba are
386 lastlba = last_lba(state->bdev);
387 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
388 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
389 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
390 (unsigned long long)lastlba);
393 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
394 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
395 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
396 (unsigned long long)lastlba);
400 /* Check that sizeof_partition_entry has the correct value */
401 if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {
402 pr_debug("GUID Partitition Entry Size check failed.\n");
406 if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
409 /* Check the GUID Partition Entry Array CRC */
410 crc = efi_crc32((const unsigned char *) (*ptes),
411 le32_to_cpu((*gpt)->num_partition_entries) *
412 le32_to_cpu((*gpt)->sizeof_partition_entry));
414 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
415 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
419 /* We're done, all's well */
432 * is_pte_valid() - tests one PTE for validity
433 * @pte is the pte to check
434 * @lastlba is last lba of the disk
436 * Description: returns 1 if valid, 0 on error.
439 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
441 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
442 le64_to_cpu(pte->starting_lba) > lastlba ||
443 le64_to_cpu(pte->ending_lba) > lastlba)
449 * compare_gpts() - Search disk for valid GPT headers and PTEs
450 * @pgpt is the primary GPT header
451 * @agpt is the alternate GPT header
452 * @lastlba is the last LBA number
453 * Description: Returns nothing. Sanity checks pgpt and agpt fields
454 * and prints warnings on discrepancies.
458 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
463 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
465 "GPT:Primary header LBA != Alt. header alternate_lba\n");
466 printk(KERN_WARNING "GPT:%lld != %lld\n",
467 (unsigned long long)le64_to_cpu(pgpt->my_lba),
468 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
471 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
473 "GPT:Primary header alternate_lba != Alt. header my_lba\n");
474 printk(KERN_WARNING "GPT:%lld != %lld\n",
475 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
476 (unsigned long long)le64_to_cpu(agpt->my_lba));
479 if (le64_to_cpu(pgpt->first_usable_lba) !=
480 le64_to_cpu(agpt->first_usable_lba)) {
481 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
482 printk(KERN_WARNING "GPT:%lld != %lld\n",
483 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
484 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
487 if (le64_to_cpu(pgpt->last_usable_lba) !=
488 le64_to_cpu(agpt->last_usable_lba)) {
489 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
490 printk(KERN_WARNING "GPT:%lld != %lld\n",
491 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
492 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
495 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
496 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
499 if (le32_to_cpu(pgpt->num_partition_entries) !=
500 le32_to_cpu(agpt->num_partition_entries)) {
501 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
503 le32_to_cpu(pgpt->num_partition_entries),
504 le32_to_cpu(agpt->num_partition_entries));
507 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
508 le32_to_cpu(agpt->sizeof_partition_entry)) {
510 "GPT:sizeof_partition_entry values don't match: "
512 le32_to_cpu(pgpt->sizeof_partition_entry),
513 le32_to_cpu(agpt->sizeof_partition_entry));
516 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
517 le32_to_cpu(agpt->partition_entry_array_crc32)) {
519 "GPT:partition_entry_array_crc32 values don't match: "
521 le32_to_cpu(pgpt->partition_entry_array_crc32),
522 le32_to_cpu(agpt->partition_entry_array_crc32));
525 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
527 "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
528 printk(KERN_WARNING "GPT:%lld != %lld\n",
529 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
530 (unsigned long long)lastlba);
534 if (le64_to_cpu(agpt->my_lba) != lastlba) {
536 "GPT:Alternate GPT header not at the end of the disk.\n");
537 printk(KERN_WARNING "GPT:%lld != %lld\n",
538 (unsigned long long)le64_to_cpu(agpt->my_lba),
539 (unsigned long long)lastlba);
545 "GPT: Use GNU Parted to correct GPT errors.\n");
550 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
552 * @gpt is a GPT header ptr, filled on return.
553 * @ptes is a PTEs ptr, filled on return.
554 * Description: Returns 1 if valid, 0 on error.
555 * If valid, returns pointers to newly allocated GPT header and PTEs.
556 * Validity depends on PMBR being valid (or being overridden by the
557 * 'gpt' kernel command line option) and finding either the Primary
558 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
559 * valid. If the Primary GPT header is not valid, the Alternate GPT header
560 * is not checked unless the 'gpt' kernel command line option is passed.
561 * This protects against devices which misreport their size, and forces
562 * the user to decide to use the Alternate GPT.
564 static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
567 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
568 gpt_header *pgpt = NULL, *agpt = NULL;
569 gpt_entry *pptes = NULL, *aptes = NULL;
570 legacy_mbr *legacymbr;
576 lastlba = last_lba(state->bdev);
578 /* This will be added to the EFI Spec. per Intel after v1.02. */
579 legacymbr = kzalloc(sizeof(*legacymbr), GFP_KERNEL);
583 read_lba(state, 0, (u8 *)legacymbr, sizeof(*legacymbr));
584 good_pmbr = is_pmbr_valid(legacymbr);
590 pr_debug("Device has a %s MBR\n",
591 good_pmbr == GPT_MBR_PROTECTIVE ?
592 "protective" : "hybrid");
595 good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
598 good_agpt = is_gpt_valid(state,
599 le64_to_cpu(pgpt->alternate_lba),
601 if (!good_agpt && force_gpt)
602 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
604 /* The obviously unsuccessful case */
605 if (!good_pgpt && !good_agpt)
608 compare_gpts(pgpt, agpt, lastlba);
618 "Alternate GPT is invalid, "
619 "using primary GPT.\n");
623 else if (good_agpt) {
629 "Primary GPT is invalid, using alternate GPT.\n");
644 * efi_partition(struct parsed_partitions *state)
647 * Description: called from check.c, if the disk contains GPT
648 * partitions, sets up partition entries in the kernel.
650 * If the first block on the disk is a legacy MBR,
651 * it will get handled by msdos_partition().
652 * If it's a Protective MBR, we'll handle it here.
654 * We do not create a Linux partition for GPT, but
655 * only for the actual data partitions.
657 * -1 if unable to read the partition table
658 * 0 if this isn't our partition table
662 int efi_partition(struct parsed_partitions *state)
664 gpt_header *gpt = NULL;
665 gpt_entry *ptes = NULL;
667 unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
669 if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
675 pr_debug("GUID Partition Table is valid! Yea!\n");
677 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
678 struct partition_meta_info *info;
679 unsigned label_count = 0;
681 u64 start = le64_to_cpu(ptes[i].starting_lba);
682 u64 size = le64_to_cpu(ptes[i].ending_lba) -
683 le64_to_cpu(ptes[i].starting_lba) + 1ULL;
685 if (!is_pte_valid(&ptes[i], last_lba(state->bdev)))
688 put_partition(state, i+1, start * ssz, size * ssz);
690 /* If this is a RAID volume, tell md */
691 if (!efi_guidcmp(ptes[i].partition_type_guid,
692 PARTITION_LINUX_RAID_GUID))
693 state->parts[i + 1].flags = ADDPART_FLAG_RAID;
695 info = &state->parts[i + 1].info;
696 efi_guid_unparse(&ptes[i].unique_partition_guid, info->uuid);
698 /* Naively convert UTF16-LE to 7 bits. */
699 label_max = min(sizeof(info->volname) - 1,
700 sizeof(ptes[i].partition_name));
701 info->volname[label_max] = 0;
702 while (label_count < label_max) {
703 u8 c = ptes[i].partition_name[label_count] & 0xff;
704 if (c && !isprint(c))
706 info->volname[label_count] = c;
709 state->parts[i + 1].has_info = true;
713 strlcat(state->pp_buf, "\n", PAGE_SIZE);