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/crc32.h>
100 #define Dprintk(x...) printk(KERN_DEBUG x)
102 #define Dprintk(x...)
105 /* This allows a kernel command line option 'gpt' to override
106 * the test for invalid PMBR. Not __initdata because reloading
107 * the partition tables happens after init too.
109 static int force_gpt;
111 force_gpt_fn(char *str)
116 __setup("gpt", force_gpt_fn);
120 * efi_crc32() - EFI version of crc32 function
121 * @buf: buffer to calculate crc32 of
122 * @len - length of buf
124 * Description: Returns EFI-style CRC32 value for @buf
126 * This function uses the little endian Ethernet polynomial
127 * but seeds the function with ~0, and xor's with ~0 at the end.
128 * Note, the EFI Specification, v1.02, has a reference to
129 * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
132 efi_crc32(const void *buf, unsigned long len)
134 return (crc32(~0L, buf, len) ^ ~0L);
138 * last_lba(): return number of last logical block of device
139 * @bdev: block device
141 * Description: Returns last LBA value on success, 0 on error.
142 * This is stored (by sd and ide-geometry) in
143 * the part[0] entry for this disk, and is the number of
144 * physical sectors available on the disk.
147 last_lba(struct block_device *bdev)
149 if (!bdev || !bdev->bd_inode)
151 return (bdev->bd_inode->i_size >> 9) - 1ULL;
155 pmbr_part_valid(struct partition *part, u64 lastlba)
157 if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
158 le32_to_cpu(part->start_sect) == 1UL)
164 * is_pmbr_valid(): test Protective MBR for validity
165 * @mbr: pointer to a legacy mbr structure
166 * @lastlba: last_lba for the whole device
168 * Description: Returns 1 if PMBR is valid, 0 otherwise.
169 * Validity depends on two things:
170 * 1) MSDOS signature is in the last two bytes of the MBR
171 * 2) One partition of type 0xEE is found
174 is_pmbr_valid(legacy_mbr *mbr, u64 lastlba)
177 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
179 for (i = 0; i < 4; i++)
180 if (pmbr_part_valid(&mbr->partition_record[i], lastlba))
186 * read_lba(): Read bytes from disk, starting at given LBA
192 * Description: Reads @count bytes from @bdev into @buffer.
193 * Returns number of bytes read on success, 0 on error.
196 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
198 size_t totalreadcount = 0;
200 if (!bdev || !buffer || lba > last_lba(bdev))
206 unsigned char *data = read_dev_sector(bdev, lba++, §);
211 memcpy(buffer, data, copied);
212 put_dev_sector(sect);
214 totalreadcount +=copied;
217 return totalreadcount;
221 * alloc_read_gpt_entries(): reads partition entries from disk
225 * Description: Returns ptes on success, NULL on error.
226 * Allocates space for PTEs based on information found in @gpt.
227 * Notes: remember to free pte when you're done!
230 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
237 count = le32_to_cpu(gpt->num_partition_entries) *
238 le32_to_cpu(gpt->sizeof_partition_entry);
241 pte = kmalloc(count, GFP_KERNEL);
244 memset(pte, 0, count);
246 if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
257 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
259 * @lba is the Logical Block Address of the partition table
261 * Description: returns GPT header on success, NULL on error. Allocates
262 * and fills a GPT header starting at @ from @bdev.
263 * Note: remember to free gpt when finished with it.
266 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
272 gpt = kmalloc(sizeof (gpt_header), GFP_KERNEL);
275 memset(gpt, 0, sizeof (gpt_header));
277 if (read_lba(bdev, lba, (u8 *) gpt,
278 sizeof (gpt_header)) < sizeof (gpt_header)) {
288 * is_gpt_valid() - tests one GPT header and PTEs for validity
290 * @lba is the logical block address of the GPT header to test
291 * @gpt is a GPT header ptr, filled on return.
292 * @ptes is a PTEs ptr, filled on return.
294 * Description: returns 1 if valid, 0 on error.
295 * If valid, returns pointers to newly allocated GPT header and PTEs.
298 is_gpt_valid(struct block_device *bdev, u64 lba,
299 gpt_header **gpt, gpt_entry **ptes)
304 if (!bdev || !gpt || !ptes)
306 if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
309 /* Check the GUID Partition Table signature */
310 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
311 Dprintk("GUID Partition Table Header signature is wrong:"
313 (unsigned long long)le64_to_cpu((*gpt)->signature),
314 (unsigned long long)GPT_HEADER_SIGNATURE);
318 /* Check the GUID Partition Table CRC */
319 origcrc = le32_to_cpu((*gpt)->header_crc32);
320 (*gpt)->header_crc32 = 0;
321 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
323 if (crc != origcrc) {
325 ("GUID Partition Table Header CRC is wrong: %x != %x\n",
329 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
331 /* Check that the my_lba entry points to the LBA that contains
332 * the GUID Partition Table */
333 if (le64_to_cpu((*gpt)->my_lba) != lba) {
334 Dprintk("GPT my_lba incorrect: %lld != %lld\n",
335 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
336 (unsigned long long)lba);
340 /* Check the first_usable_lba and last_usable_lba are
343 lastlba = last_lba(bdev);
344 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
345 Dprintk("GPT: first_usable_lba incorrect: %lld > %lld\n",
346 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
347 (unsigned long long)lastlba);
350 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
351 Dprintk("GPT: last_usable_lba incorrect: %lld > %lld\n",
352 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
353 (unsigned long long)lastlba);
357 if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
360 /* Check the GUID Partition Entry Array CRC */
361 crc = efi_crc32((const unsigned char *) (*ptes),
362 le32_to_cpu((*gpt)->num_partition_entries) *
363 le32_to_cpu((*gpt)->sizeof_partition_entry));
365 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
366 Dprintk("GUID Partitition Entry Array CRC check failed.\n");
370 /* We're done, all's well */
383 * is_pte_valid() - tests one PTE for validity
384 * @pte is the pte to check
385 * @lastlba is last lba of the disk
387 * Description: returns 1 if valid, 0 on error.
390 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
392 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
393 le64_to_cpu(pte->starting_lba) > lastlba ||
394 le64_to_cpu(pte->ending_lba) > lastlba)
400 * compare_gpts() - Search disk for valid GPT headers and PTEs
401 * @pgpt is the primary GPT header
402 * @agpt is the alternate GPT header
403 * @lastlba is the last LBA number
404 * Description: Returns nothing. Sanity checks pgpt and agpt fields
405 * and prints warnings on discrepancies.
409 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
414 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
416 "GPT:Primary header LBA != Alt. header alternate_lba\n");
417 printk(KERN_WARNING "GPT:%lld != %lld\n",
418 (unsigned long long)le64_to_cpu(pgpt->my_lba),
419 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
422 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
424 "GPT:Primary header alternate_lba != Alt. header my_lba\n");
425 printk(KERN_WARNING "GPT:%lld != %lld\n",
426 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
427 (unsigned long long)le64_to_cpu(agpt->my_lba));
430 if (le64_to_cpu(pgpt->first_usable_lba) !=
431 le64_to_cpu(agpt->first_usable_lba)) {
432 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
433 printk(KERN_WARNING "GPT:%lld != %lld\n",
434 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
435 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
438 if (le64_to_cpu(pgpt->last_usable_lba) !=
439 le64_to_cpu(agpt->last_usable_lba)) {
440 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
441 printk(KERN_WARNING "GPT:%lld != %lld\n",
442 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
443 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
446 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
447 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
450 if (le32_to_cpu(pgpt->num_partition_entries) !=
451 le32_to_cpu(agpt->num_partition_entries)) {
452 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
454 le32_to_cpu(pgpt->num_partition_entries),
455 le32_to_cpu(agpt->num_partition_entries));
458 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
459 le32_to_cpu(agpt->sizeof_partition_entry)) {
461 "GPT:sizeof_partition_entry values don't match: "
463 le32_to_cpu(pgpt->sizeof_partition_entry),
464 le32_to_cpu(agpt->sizeof_partition_entry));
467 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
468 le32_to_cpu(agpt->partition_entry_array_crc32)) {
470 "GPT:partition_entry_array_crc32 values don't match: "
472 le32_to_cpu(pgpt->partition_entry_array_crc32),
473 le32_to_cpu(agpt->partition_entry_array_crc32));
476 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
478 "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
479 printk(KERN_WARNING "GPT:%lld != %lld\n",
480 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
481 (unsigned long long)lastlba);
485 if (le64_to_cpu(agpt->my_lba) != lastlba) {
487 "GPT:Alternate GPT header not at the end of the disk.\n");
488 printk(KERN_WARNING "GPT:%lld != %lld\n",
489 (unsigned long long)le64_to_cpu(agpt->my_lba),
490 (unsigned long long)lastlba);
496 "GPT: Use GNU Parted to correct GPT errors.\n");
501 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
503 * @gpt is a GPT header ptr, filled on return.
504 * @ptes is a PTEs ptr, filled on return.
505 * Description: Returns 1 if valid, 0 on error.
506 * If valid, returns pointers to newly allocated GPT header and PTEs.
507 * Validity depends on PMBR being valid (or being overridden by the
508 * 'gpt' kernel command line option) and finding either the Primary
509 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
510 * valid. If the Primary GPT header is not valid, the Alternate GPT header
511 * is not checked unless the 'gpt' kernel command line option is passed.
512 * This protects against devices which misreport their size, and forces
513 * the user to decide to use the Alternate GPT.
516 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
518 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
519 gpt_header *pgpt = NULL, *agpt = NULL;
520 gpt_entry *pptes = NULL, *aptes = NULL;
521 legacy_mbr *legacymbr = NULL;
523 if (!bdev || !gpt || !ptes)
526 lastlba = last_lba(bdev);
528 /* This will be added to the EFI Spec. per Intel after v1.02. */
529 legacymbr = kmalloc(sizeof (*legacymbr), GFP_KERNEL);
531 memset(legacymbr, 0, sizeof (*legacymbr));
532 read_lba(bdev, 0, (u8 *) legacymbr,
533 sizeof (*legacymbr));
534 good_pmbr = is_pmbr_valid(legacymbr, lastlba);
542 good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
545 good_agpt = is_gpt_valid(bdev,
546 le64_to_cpu(pgpt->alternate_lba),
548 if (!good_agpt && force_gpt)
549 good_agpt = is_gpt_valid(bdev, lastlba,
552 /* The obviously unsuccessful case */
553 if (!good_pgpt && !good_agpt)
556 compare_gpts(pgpt, agpt, lastlba);
566 "Alternate GPT is invalid, "
567 "using primary GPT.\n");
571 else if (good_agpt) {
577 "Primary GPT is invalid, using alternate GPT.\n");
592 * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
596 * Description: called from check.c, if the disk contains GPT
597 * partitions, sets up partition entries in the kernel.
599 * If the first block on the disk is a legacy MBR,
600 * it will get handled by msdos_partition().
601 * If it's a Protective MBR, we'll handle it here.
603 * We do not create a Linux partition for GPT, but
604 * only for the actual data partitions.
606 * -1 if unable to read the partition table
607 * 0 if this isn't our partition table
612 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
614 gpt_header *gpt = NULL;
615 gpt_entry *ptes = NULL;
618 if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
624 Dprintk("GUID Partition Table is valid! Yea!\n");
626 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
627 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
630 put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
631 (le64_to_cpu(ptes[i].ending_lba) -
632 le64_to_cpu(ptes[i].starting_lba) +
635 /* If this is a RAID volume, tell md */
636 if (!efi_guidcmp(ptes[i].partition_type_guid,
637 PARTITION_LINUX_RAID_GUID))
638 state->parts[i+1].flags = 1;