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.
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.
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.
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
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
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.
41 * Mon Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
42 * - Removed __PRIPTR_PREFIX - not being used
44 * Mon Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
45 * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
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.
53 * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
54 * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
56 * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
57 * - Changed function comments to DocBook style per Andreas Dilger suggestion.
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()
64 * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com>
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.
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.
79 * Tue Dec 5 2000 Matt Domsch <Matt_Domsch@dell.com>
80 * - Moved crc32() to linux/lib, added efi_crc32().
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.
86 * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
87 * - Fixed the last_lba() call to return the proper last block
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.
93 ************************************************************/
94 #include <linux/config.h>
95 #include <linux/crc32.h>
101 #define Dprintk(x...) printk(KERN_DEBUG x)
103 #define Dprintk(x...)
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.
148 last_lba(struct block_device *bdev)
150 if (!bdev || !bdev->bd_inode)
152 return (bdev->bd_inode->i_size >> 9) - 1ULL;
156 pmbr_part_valid(struct partition *part, u64 lastlba)
158 if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
159 le32_to_cpu(part->start_sect) == 1UL)
165 * is_pmbr_valid(): test Protective MBR for validity
166 * @mbr: pointer to a legacy mbr structure
167 * @lastlba: last_lba for the whole device
169 * Description: Returns 1 if PMBR is valid, 0 otherwise.
170 * Validity depends on two things:
171 * 1) MSDOS signature is in the last two bytes of the MBR
172 * 2) One partition of type 0xEE is found
175 is_pmbr_valid(legacy_mbr *mbr, u64 lastlba)
178 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
180 for (i = 0; i < 4; i++)
181 if (pmbr_part_valid(&mbr->partition_record[i], lastlba))
187 * read_lba(): Read bytes from disk, starting at given LBA
193 * Description: Reads @count bytes from @bdev into @buffer.
194 * Returns number of bytes read on success, 0 on error.
197 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
199 size_t totalreadcount = 0;
201 if (!bdev || !buffer || lba > last_lba(bdev))
207 unsigned char *data = read_dev_sector(bdev, lba++, §);
212 memcpy(buffer, data, copied);
213 put_dev_sector(sect);
215 totalreadcount +=copied;
218 return totalreadcount;
222 * alloc_read_gpt_entries(): reads partition entries from disk
226 * Description: Returns ptes on success, NULL on error.
227 * Allocates space for PTEs based on information found in @gpt.
228 * Notes: remember to free pte when you're done!
231 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
238 count = le32_to_cpu(gpt->num_partition_entries) *
239 le32_to_cpu(gpt->sizeof_partition_entry);
242 pte = kmalloc(count, GFP_KERNEL);
245 memset(pte, 0, count);
247 if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
258 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
260 * @lba is the Logical Block Address of the partition table
262 * Description: returns GPT header on success, NULL on error. Allocates
263 * and fills a GPT header starting at @ from @bdev.
264 * Note: remember to free gpt when finished with it.
267 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
273 gpt = kmalloc(sizeof (gpt_header), GFP_KERNEL);
276 memset(gpt, 0, sizeof (gpt_header));
278 if (read_lba(bdev, lba, (u8 *) gpt,
279 sizeof (gpt_header)) < sizeof (gpt_header)) {
289 * is_gpt_valid() - tests one GPT header and PTEs for validity
291 * @lba is the logical block address of the GPT header to test
292 * @gpt is a GPT header ptr, filled on return.
293 * @ptes is a PTEs ptr, filled on return.
295 * Description: returns 1 if valid, 0 on error.
296 * If valid, returns pointers to newly allocated GPT header and PTEs.
299 is_gpt_valid(struct block_device *bdev, u64 lba,
300 gpt_header **gpt, gpt_entry **ptes)
305 if (!bdev || !gpt || !ptes)
307 if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
310 /* Check the GUID Partition Table signature */
311 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
312 Dprintk("GUID Partition Table Header signature is wrong:"
314 (unsigned long long)le64_to_cpu((*gpt)->signature),
315 (unsigned long long)GPT_HEADER_SIGNATURE);
319 /* Check the GUID Partition Table CRC */
320 origcrc = le32_to_cpu((*gpt)->header_crc32);
321 (*gpt)->header_crc32 = 0;
322 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
324 if (crc != origcrc) {
326 ("GUID Partition Table Header CRC is wrong: %x != %x\n",
330 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
332 /* Check that the my_lba entry points to the LBA that contains
333 * the GUID Partition Table */
334 if (le64_to_cpu((*gpt)->my_lba) != lba) {
335 Dprintk("GPT my_lba incorrect: %lld != %lld\n",
336 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
337 (unsigned long long)lba);
341 /* Check the first_usable_lba and last_usable_lba are
344 lastlba = last_lba(bdev);
345 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
346 Dprintk("GPT: first_usable_lba incorrect: %lld > %lld\n",
347 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
348 (unsigned long long)lastlba);
351 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
352 Dprintk("GPT: last_usable_lba incorrect: %lld > %lld\n",
353 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
354 (unsigned long long)lastlba);
358 if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
361 /* Check the GUID Partition Entry Array CRC */
362 crc = efi_crc32((const unsigned char *) (*ptes),
363 le32_to_cpu((*gpt)->num_partition_entries) *
364 le32_to_cpu((*gpt)->sizeof_partition_entry));
366 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
367 Dprintk("GUID Partitition Entry Array CRC check failed.\n");
371 /* We're done, all's well */
384 * is_pte_valid() - tests one PTE for validity
385 * @pte is the pte to check
386 * @lastlba is last lba of the disk
388 * Description: returns 1 if valid, 0 on error.
391 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
393 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
394 le64_to_cpu(pte->starting_lba) > lastlba ||
395 le64_to_cpu(pte->ending_lba) > lastlba)
401 * compare_gpts() - Search disk for valid GPT headers and PTEs
402 * @pgpt is the primary GPT header
403 * @agpt is the alternate GPT header
404 * @lastlba is the last LBA number
405 * Description: Returns nothing. Sanity checks pgpt and agpt fields
406 * and prints warnings on discrepancies.
410 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
415 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
417 "GPT:Primary header LBA != Alt. header alternate_lba\n");
418 printk(KERN_WARNING "GPT:%lld != %lld\n",
419 (unsigned long long)le64_to_cpu(pgpt->my_lba),
420 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
423 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
425 "GPT:Primary header alternate_lba != Alt. header my_lba\n");
426 printk(KERN_WARNING "GPT:%lld != %lld\n",
427 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
428 (unsigned long long)le64_to_cpu(agpt->my_lba));
431 if (le64_to_cpu(pgpt->first_usable_lba) !=
432 le64_to_cpu(agpt->first_usable_lba)) {
433 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
434 printk(KERN_WARNING "GPT:%lld != %lld\n",
435 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
436 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
439 if (le64_to_cpu(pgpt->last_usable_lba) !=
440 le64_to_cpu(agpt->last_usable_lba)) {
441 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
442 printk(KERN_WARNING "GPT:%lld != %lld\n",
443 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
444 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
447 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
448 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
451 if (le32_to_cpu(pgpt->num_partition_entries) !=
452 le32_to_cpu(agpt->num_partition_entries)) {
453 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
455 le32_to_cpu(pgpt->num_partition_entries),
456 le32_to_cpu(agpt->num_partition_entries));
459 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
460 le32_to_cpu(agpt->sizeof_partition_entry)) {
462 "GPT:sizeof_partition_entry values don't match: "
464 le32_to_cpu(pgpt->sizeof_partition_entry),
465 le32_to_cpu(agpt->sizeof_partition_entry));
468 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
469 le32_to_cpu(agpt->partition_entry_array_crc32)) {
471 "GPT:partition_entry_array_crc32 values don't match: "
473 le32_to_cpu(pgpt->partition_entry_array_crc32),
474 le32_to_cpu(agpt->partition_entry_array_crc32));
477 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
479 "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
480 printk(KERN_WARNING "GPT:%lld != %lld\n",
481 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
482 (unsigned long long)lastlba);
486 if (le64_to_cpu(agpt->my_lba) != lastlba) {
488 "GPT:Alternate GPT header not at the end of the disk.\n");
489 printk(KERN_WARNING "GPT:%lld != %lld\n",
490 (unsigned long long)le64_to_cpu(agpt->my_lba),
491 (unsigned long long)lastlba);
497 "GPT: Use GNU Parted to correct GPT errors.\n");
502 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
504 * @gpt is a GPT header ptr, filled on return.
505 * @ptes is a PTEs ptr, filled on return.
506 * Description: Returns 1 if valid, 0 on error.
507 * If valid, returns pointers to newly allocated GPT header and PTEs.
508 * Validity depends on PMBR being valid (or being overridden by the
509 * 'gpt' kernel command line option) and finding either the Primary
510 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
511 * valid. If the Primary GPT header is not valid, the Alternate GPT header
512 * is not checked unless the 'gpt' kernel command line option is passed.
513 * This protects against devices which misreport their size, and forces
514 * the user to decide to use the Alternate GPT.
517 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
519 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
520 gpt_header *pgpt = NULL, *agpt = NULL;
521 gpt_entry *pptes = NULL, *aptes = NULL;
522 legacy_mbr *legacymbr = NULL;
524 if (!bdev || !gpt || !ptes)
527 lastlba = last_lba(bdev);
529 /* This will be added to the EFI Spec. per Intel after v1.02. */
530 legacymbr = kmalloc(sizeof (*legacymbr), GFP_KERNEL);
532 memset(legacymbr, 0, sizeof (*legacymbr));
533 read_lba(bdev, 0, (u8 *) legacymbr,
534 sizeof (*legacymbr));
535 good_pmbr = is_pmbr_valid(legacymbr, lastlba);
543 good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
546 good_agpt = is_gpt_valid(bdev,
547 le64_to_cpu(pgpt->alternate_lba),
549 if (!good_agpt && force_gpt)
550 good_agpt = is_gpt_valid(bdev, lastlba,
553 /* The obviously unsuccessful case */
554 if (!good_pgpt && !good_agpt)
557 compare_gpts(pgpt, agpt, lastlba);
567 "Alternate GPT is invalid, "
568 "using primary GPT.\n");
572 else if (good_agpt) {
578 "Primary GPT is invalid, using alternate GPT.\n");
593 * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
597 * Description: called from check.c, if the disk contains GPT
598 * partitions, sets up partition entries in the kernel.
600 * If the first block on the disk is a legacy MBR,
601 * it will get handled by msdos_partition().
602 * If it's a Protective MBR, we'll handle it here.
604 * We do not create a Linux partition for GPT, but
605 * only for the actual data partitions.
607 * -1 if unable to read the partition table
608 * 0 if this isn't our partition table
613 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
615 gpt_header *gpt = NULL;
616 gpt_entry *ptes = NULL;
619 if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
625 Dprintk("GUID Partition Table is valid! Yea!\n");
627 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
628 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
631 put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
632 (le64_to_cpu(ptes[i].ending_lba) -
633 le64_to_cpu(ptes[i].starting_lba) +
636 /* If this is a RAID volume, tell md */
637 if (!efi_guidcmp(ptes[i].partition_type_guid,
638 PARTITION_LINUX_RAID_GUID))
639 state->parts[i+1].flags = 1;