Linux 2.6.28.1
[linux/fpc-iii.git] / fs / partitions / efi.c
blob038a6022152fd15d84fb48b70fab816b971a8f7e
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
23 * TODO:
25 * Changelog:
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>
65 * - Style cleanups
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>
95 #include "check.h"
96 #include "efi.h"
98 /* This allows a kernel command line option 'gpt' to override
99 * the test for invalid PMBR. Not __initdata because reloading
100 * the partition tables happens after init too.
102 static int force_gpt;
103 static int __init
104 force_gpt_fn(char *str)
106 force_gpt = 1;
107 return 1;
109 __setup("gpt", force_gpt_fn);
113 * efi_crc32() - EFI version of crc32 function
114 * @buf: buffer to calculate crc32 of
115 * @len - length of buf
117 * Description: Returns EFI-style CRC32 value for @buf
119 * This function uses the little endian Ethernet polynomial
120 * but seeds the function with ~0, and xor's with ~0 at the end.
121 * Note, the EFI Specification, v1.02, has a reference to
122 * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
124 static inline u32
125 efi_crc32(const void *buf, unsigned long len)
127 return (crc32(~0L, buf, len) ^ ~0L);
131 * last_lba(): return number of last logical block of device
132 * @bdev: block device
134 * Description: Returns last LBA value on success, 0 on error.
135 * This is stored (by sd and ide-geometry) in
136 * the part[0] entry for this disk, and is the number of
137 * physical sectors available on the disk.
139 static u64
140 last_lba(struct block_device *bdev)
142 if (!bdev || !bdev->bd_inode)
143 return 0;
144 return (bdev->bd_inode->i_size >> 9) - 1ULL;
147 static inline int
148 pmbr_part_valid(struct partition *part)
150 if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
151 le32_to_cpu(part->start_sect) == 1UL)
152 return 1;
153 return 0;
157 * is_pmbr_valid(): test Protective MBR for validity
158 * @mbr: pointer to a legacy mbr structure
160 * Description: Returns 1 if PMBR is valid, 0 otherwise.
161 * Validity depends on two things:
162 * 1) MSDOS signature is in the last two bytes of the MBR
163 * 2) One partition of type 0xEE is found
165 static int
166 is_pmbr_valid(legacy_mbr *mbr)
168 int i;
169 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
170 return 0;
171 for (i = 0; i < 4; i++)
172 if (pmbr_part_valid(&mbr->partition_record[i]))
173 return 1;
174 return 0;
178 * read_lba(): Read bytes from disk, starting at given LBA
179 * @bdev
180 * @lba
181 * @buffer
182 * @size_t
184 * Description: Reads @count bytes from @bdev into @buffer.
185 * Returns number of bytes read on success, 0 on error.
187 static size_t
188 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
190 size_t totalreadcount = 0;
192 if (!bdev || !buffer || lba > last_lba(bdev))
193 return 0;
195 while (count) {
196 int copied = 512;
197 Sector sect;
198 unsigned char *data = read_dev_sector(bdev, lba++, &sect);
199 if (!data)
200 break;
201 if (copied > count)
202 copied = count;
203 memcpy(buffer, data, copied);
204 put_dev_sector(sect);
205 buffer += copied;
206 totalreadcount +=copied;
207 count -= copied;
209 return totalreadcount;
213 * alloc_read_gpt_entries(): reads partition entries from disk
214 * @bdev
215 * @gpt - GPT header
217 * Description: Returns ptes on success, NULL on error.
218 * Allocates space for PTEs based on information found in @gpt.
219 * Notes: remember to free pte when you're done!
221 static gpt_entry *
222 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
224 size_t count;
225 gpt_entry *pte;
226 if (!bdev || !gpt)
227 return NULL;
229 count = le32_to_cpu(gpt->num_partition_entries) *
230 le32_to_cpu(gpt->sizeof_partition_entry);
231 if (!count)
232 return NULL;
233 pte = kzalloc(count, GFP_KERNEL);
234 if (!pte)
235 return NULL;
237 if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba),
238 (u8 *) pte,
239 count) < count) {
240 kfree(pte);
241 pte=NULL;
242 return NULL;
244 return pte;
248 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
249 * @bdev
250 * @lba is the Logical Block Address of the partition table
252 * Description: returns GPT header on success, NULL on error. Allocates
253 * and fills a GPT header starting at @ from @bdev.
254 * Note: remember to free gpt when finished with it.
256 static gpt_header *
257 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
259 gpt_header *gpt;
260 if (!bdev)
261 return NULL;
263 gpt = kzalloc(sizeof (gpt_header), GFP_KERNEL);
264 if (!gpt)
265 return NULL;
267 if (read_lba(bdev, lba, (u8 *) gpt,
268 sizeof (gpt_header)) < sizeof (gpt_header)) {
269 kfree(gpt);
270 gpt=NULL;
271 return NULL;
274 return gpt;
278 * is_gpt_valid() - tests one GPT header and PTEs for validity
279 * @bdev
280 * @lba is the logical block address of the GPT header to test
281 * @gpt is a GPT header ptr, filled on return.
282 * @ptes is a PTEs ptr, filled on return.
284 * Description: returns 1 if valid, 0 on error.
285 * If valid, returns pointers to newly allocated GPT header and PTEs.
287 static int
288 is_gpt_valid(struct block_device *bdev, u64 lba,
289 gpt_header **gpt, gpt_entry **ptes)
291 u32 crc, origcrc;
292 u64 lastlba;
294 if (!bdev || !gpt || !ptes)
295 return 0;
296 if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
297 return 0;
299 /* Check the GUID Partition Table signature */
300 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
301 pr_debug("GUID Partition Table Header signature is wrong:"
302 "%lld != %lld\n",
303 (unsigned long long)le64_to_cpu((*gpt)->signature),
304 (unsigned long long)GPT_HEADER_SIGNATURE);
305 goto fail;
308 /* Check the GUID Partition Table CRC */
309 origcrc = le32_to_cpu((*gpt)->header_crc32);
310 (*gpt)->header_crc32 = 0;
311 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
313 if (crc != origcrc) {
314 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
315 crc, origcrc);
316 goto fail;
318 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
320 /* Check that the my_lba entry points to the LBA that contains
321 * the GUID Partition Table */
322 if (le64_to_cpu((*gpt)->my_lba) != lba) {
323 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
324 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
325 (unsigned long long)lba);
326 goto fail;
329 /* Check the first_usable_lba and last_usable_lba are
330 * within the disk.
332 lastlba = last_lba(bdev);
333 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
334 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
335 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
336 (unsigned long long)lastlba);
337 goto fail;
339 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
340 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
341 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
342 (unsigned long long)lastlba);
343 goto fail;
346 if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
347 goto fail;
349 /* Check the GUID Partition Entry Array CRC */
350 crc = efi_crc32((const unsigned char *) (*ptes),
351 le32_to_cpu((*gpt)->num_partition_entries) *
352 le32_to_cpu((*gpt)->sizeof_partition_entry));
354 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
355 pr_debug("GUID Partitition Entry Array CRC check failed.\n");
356 goto fail_ptes;
359 /* We're done, all's well */
360 return 1;
362 fail_ptes:
363 kfree(*ptes);
364 *ptes = NULL;
365 fail:
366 kfree(*gpt);
367 *gpt = NULL;
368 return 0;
372 * is_pte_valid() - tests one PTE for validity
373 * @pte is the pte to check
374 * @lastlba is last lba of the disk
376 * Description: returns 1 if valid, 0 on error.
378 static inline int
379 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
381 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
382 le64_to_cpu(pte->starting_lba) > lastlba ||
383 le64_to_cpu(pte->ending_lba) > lastlba)
384 return 0;
385 return 1;
389 * compare_gpts() - Search disk for valid GPT headers and PTEs
390 * @pgpt is the primary GPT header
391 * @agpt is the alternate GPT header
392 * @lastlba is the last LBA number
393 * Description: Returns nothing. Sanity checks pgpt and agpt fields
394 * and prints warnings on discrepancies.
397 static void
398 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
400 int error_found = 0;
401 if (!pgpt || !agpt)
402 return;
403 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
404 printk(KERN_WARNING
405 "GPT:Primary header LBA != Alt. header alternate_lba\n");
406 printk(KERN_WARNING "GPT:%lld != %lld\n",
407 (unsigned long long)le64_to_cpu(pgpt->my_lba),
408 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
409 error_found++;
411 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
412 printk(KERN_WARNING
413 "GPT:Primary header alternate_lba != Alt. header my_lba\n");
414 printk(KERN_WARNING "GPT:%lld != %lld\n",
415 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
416 (unsigned long long)le64_to_cpu(agpt->my_lba));
417 error_found++;
419 if (le64_to_cpu(pgpt->first_usable_lba) !=
420 le64_to_cpu(agpt->first_usable_lba)) {
421 printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
422 printk(KERN_WARNING "GPT:%lld != %lld\n",
423 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
424 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
425 error_found++;
427 if (le64_to_cpu(pgpt->last_usable_lba) !=
428 le64_to_cpu(agpt->last_usable_lba)) {
429 printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
430 printk(KERN_WARNING "GPT:%lld != %lld\n",
431 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
432 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
433 error_found++;
435 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
436 printk(KERN_WARNING "GPT:disk_guids don't match.\n");
437 error_found++;
439 if (le32_to_cpu(pgpt->num_partition_entries) !=
440 le32_to_cpu(agpt->num_partition_entries)) {
441 printk(KERN_WARNING "GPT:num_partition_entries don't match: "
442 "0x%x != 0x%x\n",
443 le32_to_cpu(pgpt->num_partition_entries),
444 le32_to_cpu(agpt->num_partition_entries));
445 error_found++;
447 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
448 le32_to_cpu(agpt->sizeof_partition_entry)) {
449 printk(KERN_WARNING
450 "GPT:sizeof_partition_entry values don't match: "
451 "0x%x != 0x%x\n",
452 le32_to_cpu(pgpt->sizeof_partition_entry),
453 le32_to_cpu(agpt->sizeof_partition_entry));
454 error_found++;
456 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
457 le32_to_cpu(agpt->partition_entry_array_crc32)) {
458 printk(KERN_WARNING
459 "GPT:partition_entry_array_crc32 values don't match: "
460 "0x%x != 0x%x\n",
461 le32_to_cpu(pgpt->partition_entry_array_crc32),
462 le32_to_cpu(agpt->partition_entry_array_crc32));
463 error_found++;
465 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
466 printk(KERN_WARNING
467 "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
468 printk(KERN_WARNING "GPT:%lld != %lld\n",
469 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
470 (unsigned long long)lastlba);
471 error_found++;
474 if (le64_to_cpu(agpt->my_lba) != lastlba) {
475 printk(KERN_WARNING
476 "GPT:Alternate GPT header not at the end of the disk.\n");
477 printk(KERN_WARNING "GPT:%lld != %lld\n",
478 (unsigned long long)le64_to_cpu(agpt->my_lba),
479 (unsigned long long)lastlba);
480 error_found++;
483 if (error_found)
484 printk(KERN_WARNING
485 "GPT: Use GNU Parted to correct GPT errors.\n");
486 return;
490 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
491 * @bdev
492 * @gpt is a GPT header ptr, filled on return.
493 * @ptes is a PTEs ptr, filled on return.
494 * Description: Returns 1 if valid, 0 on error.
495 * If valid, returns pointers to newly allocated GPT header and PTEs.
496 * Validity depends on PMBR being valid (or being overridden by the
497 * 'gpt' kernel command line option) and finding either the Primary
498 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
499 * valid. If the Primary GPT header is not valid, the Alternate GPT header
500 * is not checked unless the 'gpt' kernel command line option is passed.
501 * This protects against devices which misreport their size, and forces
502 * the user to decide to use the Alternate GPT.
504 static int
505 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
507 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
508 gpt_header *pgpt = NULL, *agpt = NULL;
509 gpt_entry *pptes = NULL, *aptes = NULL;
510 legacy_mbr *legacymbr;
511 u64 lastlba;
512 if (!bdev || !gpt || !ptes)
513 return 0;
515 lastlba = last_lba(bdev);
516 if (!force_gpt) {
517 /* This will be added to the EFI Spec. per Intel after v1.02. */
518 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
519 if (legacymbr) {
520 read_lba(bdev, 0, (u8 *) legacymbr,
521 sizeof (*legacymbr));
522 good_pmbr = is_pmbr_valid(legacymbr);
523 kfree(legacymbr);
525 if (!good_pmbr)
526 goto fail;
529 good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA,
530 &pgpt, &pptes);
531 if (good_pgpt)
532 good_agpt = is_gpt_valid(bdev,
533 le64_to_cpu(pgpt->alternate_lba),
534 &agpt, &aptes);
535 if (!good_agpt && force_gpt)
536 good_agpt = is_gpt_valid(bdev, lastlba,
537 &agpt, &aptes);
539 /* The obviously unsuccessful case */
540 if (!good_pgpt && !good_agpt)
541 goto fail;
543 compare_gpts(pgpt, agpt, lastlba);
545 /* The good cases */
546 if (good_pgpt) {
547 *gpt = pgpt;
548 *ptes = pptes;
549 kfree(agpt);
550 kfree(aptes);
551 if (!good_agpt) {
552 printk(KERN_WARNING
553 "Alternate GPT is invalid, "
554 "using primary GPT.\n");
556 return 1;
558 else if (good_agpt) {
559 *gpt = agpt;
560 *ptes = aptes;
561 kfree(pgpt);
562 kfree(pptes);
563 printk(KERN_WARNING
564 "Primary GPT is invalid, using alternate GPT.\n");
565 return 1;
568 fail:
569 kfree(pgpt);
570 kfree(agpt);
571 kfree(pptes);
572 kfree(aptes);
573 *gpt = NULL;
574 *ptes = NULL;
575 return 0;
579 * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
580 * @state
581 * @bdev
583 * Description: called from check.c, if the disk contains GPT
584 * partitions, sets up partition entries in the kernel.
586 * If the first block on the disk is a legacy MBR,
587 * it will get handled by msdos_partition().
588 * If it's a Protective MBR, we'll handle it here.
590 * We do not create a Linux partition for GPT, but
591 * only for the actual data partitions.
592 * Returns:
593 * -1 if unable to read the partition table
594 * 0 if this isn't our partition table
595 * 1 if successful
599 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
601 gpt_header *gpt = NULL;
602 gpt_entry *ptes = NULL;
603 u32 i;
605 if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
606 kfree(gpt);
607 kfree(ptes);
608 return 0;
611 pr_debug("GUID Partition Table is valid! Yea!\n");
613 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
614 if (!is_pte_valid(&ptes[i], last_lba(bdev)))
615 continue;
617 put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
618 (le64_to_cpu(ptes[i].ending_lba) -
619 le64_to_cpu(ptes[i].starting_lba) +
620 1ULL));
622 /* If this is a RAID volume, tell md */
623 if (!efi_guidcmp(ptes[i].partition_type_guid,
624 PARTITION_LINUX_RAID_GUID))
625 state->parts[i+1].flags = 1;
627 kfree(ptes);
628 kfree(gpt);
629 printk("\n");
630 return 1;