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1da177e4 LT |
1 | /************************************************************ |
2 | * EFI GUID Partition Table handling | |
7d13af32 KZ |
3 | * |
4 | * http://www.uefi.org/specs/ | |
5 | * http://www.intel.com/technology/efi/ | |
6 | * | |
1da177e4 LT |
7 | * efi.[ch] by Matt Domsch <Matt_Domsch@dell.com> |
8 | * Copyright 2000,2001,2002,2004 Dell Inc. | |
9 | * | |
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. | |
14 | * | |
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. | |
19 | * | |
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 | |
23 | * | |
24 | * | |
25 | * TODO: | |
26 | * | |
27 | * Changelog: | |
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 | |
32 | * | |
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. | |
42 | * | |
43 | * Mon Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com> | |
44 | * - Removed __PRIPTR_PREFIX - not being used | |
45 | * | |
46 | * Mon Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com> | |
47 | * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied | |
48 | * | |
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. | |
54 | * | |
55 | * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com> | |
56 | * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck | |
57 | * | |
58 | * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com> | |
59 | * - Changed function comments to DocBook style per Andreas Dilger suggestion. | |
60 | * | |
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() | |
65 | * | |
66 | * Mon Oct 01 2001 Matt Domsch <Matt_Domsch@dell.com> | |
67 | * - Style cleanups | |
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. | |
76 | * | |
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. | |
80 | * | |
81 | * Tue Dec 5 2000 Matt Domsch <Matt_Domsch@dell.com> | |
82 | * - Moved crc32() to linux/lib, added efi_crc32(). | |
83 | * | |
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. | |
87 | * | |
88 | * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com> | |
89 | * - Fixed the last_lba() call to return the proper last block | |
90 | * | |
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. | |
94 | * | |
95 | ************************************************************/ | |
1da177e4 | 96 | #include <linux/crc32.h> |
7d13af32 | 97 | #include <linux/math64.h> |
1da177e4 LT |
98 | #include "check.h" |
99 | #include "efi.h" | |
100 | ||
1da177e4 LT |
101 | /* This allows a kernel command line option 'gpt' to override |
102 | * the test for invalid PMBR. Not __initdata because reloading | |
103 | * the partition tables happens after init too. | |
104 | */ | |
105 | static int force_gpt; | |
106 | static int __init | |
107 | force_gpt_fn(char *str) | |
108 | { | |
109 | force_gpt = 1; | |
110 | return 1; | |
111 | } | |
112 | __setup("gpt", force_gpt_fn); | |
113 | ||
114 | ||
115 | /** | |
116 | * efi_crc32() - EFI version of crc32 function | |
117 | * @buf: buffer to calculate crc32 of | |
118 | * @len - length of buf | |
119 | * | |
120 | * Description: Returns EFI-style CRC32 value for @buf | |
121 | * | |
122 | * This function uses the little endian Ethernet polynomial | |
123 | * but seeds the function with ~0, and xor's with ~0 at the end. | |
124 | * Note, the EFI Specification, v1.02, has a reference to | |
125 | * Dr. Dobbs Journal, May 1994 (actually it's in May 1992). | |
126 | */ | |
127 | static inline u32 | |
128 | efi_crc32(const void *buf, unsigned long len) | |
129 | { | |
130 | return (crc32(~0L, buf, len) ^ ~0L); | |
131 | } | |
132 | ||
133 | /** | |
134 | * last_lba(): return number of last logical block of device | |
135 | * @bdev: block device | |
136 | * | |
137 | * Description: Returns last LBA value on success, 0 on error. | |
138 | * This is stored (by sd and ide-geometry) in | |
139 | * the part[0] entry for this disk, and is the number of | |
140 | * physical sectors available on the disk. | |
141 | */ | |
142 | static u64 | |
143 | last_lba(struct block_device *bdev) | |
144 | { | |
145 | if (!bdev || !bdev->bd_inode) | |
146 | return 0; | |
7d13af32 KZ |
147 | return div_u64(bdev->bd_inode->i_size, |
148 | bdev_logical_block_size(bdev)) - 1ULL; | |
1da177e4 LT |
149 | } |
150 | ||
151 | static inline int | |
4c64c30a | 152 | pmbr_part_valid(struct partition *part) |
1da177e4 LT |
153 | { |
154 | if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT && | |
155 | le32_to_cpu(part->start_sect) == 1UL) | |
156 | return 1; | |
157 | return 0; | |
158 | } | |
159 | ||
160 | /** | |
161 | * is_pmbr_valid(): test Protective MBR for validity | |
162 | * @mbr: pointer to a legacy mbr structure | |
1da177e4 LT |
163 | * |
164 | * Description: Returns 1 if PMBR is valid, 0 otherwise. | |
165 | * Validity depends on two things: | |
166 | * 1) MSDOS signature is in the last two bytes of the MBR | |
167 | * 2) One partition of type 0xEE is found | |
168 | */ | |
169 | static int | |
4c64c30a | 170 | is_pmbr_valid(legacy_mbr *mbr) |
1da177e4 LT |
171 | { |
172 | int i; | |
173 | if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE) | |
174 | return 0; | |
175 | for (i = 0; i < 4; i++) | |
4c64c30a | 176 | if (pmbr_part_valid(&mbr->partition_record[i])) |
1da177e4 LT |
177 | return 1; |
178 | return 0; | |
179 | } | |
180 | ||
181 | /** | |
182 | * read_lba(): Read bytes from disk, starting at given LBA | |
183 | * @bdev | |
184 | * @lba | |
185 | * @buffer | |
186 | * @size_t | |
187 | * | |
188 | * Description: Reads @count bytes from @bdev into @buffer. | |
189 | * Returns number of bytes read on success, 0 on error. | |
190 | */ | |
191 | static size_t | |
192 | read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count) | |
193 | { | |
194 | size_t totalreadcount = 0; | |
7d13af32 | 195 | sector_t n = lba * (bdev_logical_block_size(bdev) / 512); |
1da177e4 LT |
196 | |
197 | if (!bdev || !buffer || lba > last_lba(bdev)) | |
198 | return 0; | |
199 | ||
200 | while (count) { | |
201 | int copied = 512; | |
202 | Sector sect; | |
7d13af32 | 203 | unsigned char *data = read_dev_sector(bdev, n++, §); |
1da177e4 LT |
204 | if (!data) |
205 | break; | |
206 | if (copied > count) | |
207 | copied = count; | |
208 | memcpy(buffer, data, copied); | |
209 | put_dev_sector(sect); | |
210 | buffer += copied; | |
211 | totalreadcount +=copied; | |
212 | count -= copied; | |
213 | } | |
214 | return totalreadcount; | |
215 | } | |
216 | ||
217 | /** | |
218 | * alloc_read_gpt_entries(): reads partition entries from disk | |
219 | * @bdev | |
220 | * @gpt - GPT header | |
221 | * | |
222 | * Description: Returns ptes on success, NULL on error. | |
223 | * Allocates space for PTEs based on information found in @gpt. | |
224 | * Notes: remember to free pte when you're done! | |
225 | */ | |
226 | static gpt_entry * | |
227 | alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt) | |
228 | { | |
229 | size_t count; | |
230 | gpt_entry *pte; | |
231 | if (!bdev || !gpt) | |
232 | return NULL; | |
233 | ||
234 | count = le32_to_cpu(gpt->num_partition_entries) * | |
235 | le32_to_cpu(gpt->sizeof_partition_entry); | |
236 | if (!count) | |
237 | return NULL; | |
f8314dc6 | 238 | pte = kzalloc(count, GFP_KERNEL); |
1da177e4 LT |
239 | if (!pte) |
240 | return NULL; | |
1da177e4 LT |
241 | |
242 | if (read_lba(bdev, le64_to_cpu(gpt->partition_entry_lba), | |
243 | (u8 *) pte, | |
244 | count) < count) { | |
245 | kfree(pte); | |
246 | pte=NULL; | |
247 | return NULL; | |
248 | } | |
249 | return pte; | |
250 | } | |
251 | ||
252 | /** | |
253 | * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk | |
254 | * @bdev | |
255 | * @lba is the Logical Block Address of the partition table | |
256 | * | |
257 | * Description: returns GPT header on success, NULL on error. Allocates | |
258 | * and fills a GPT header starting at @ from @bdev. | |
259 | * Note: remember to free gpt when finished with it. | |
260 | */ | |
261 | static gpt_header * | |
262 | alloc_read_gpt_header(struct block_device *bdev, u64 lba) | |
263 | { | |
264 | gpt_header *gpt; | |
87038c2d KZ |
265 | unsigned ssz = bdev_logical_block_size(bdev); |
266 | ||
1da177e4 LT |
267 | if (!bdev) |
268 | return NULL; | |
269 | ||
87038c2d | 270 | gpt = kzalloc(ssz, GFP_KERNEL); |
1da177e4 LT |
271 | if (!gpt) |
272 | return NULL; | |
1da177e4 | 273 | |
87038c2d | 274 | if (read_lba(bdev, lba, (u8 *) gpt, ssz) < ssz) { |
1da177e4 LT |
275 | kfree(gpt); |
276 | gpt=NULL; | |
277 | return NULL; | |
278 | } | |
279 | ||
280 | return gpt; | |
281 | } | |
282 | ||
283 | /** | |
284 | * is_gpt_valid() - tests one GPT header and PTEs for validity | |
285 | * @bdev | |
286 | * @lba is the logical block address of the GPT header to test | |
287 | * @gpt is a GPT header ptr, filled on return. | |
288 | * @ptes is a PTEs ptr, filled on return. | |
289 | * | |
290 | * Description: returns 1 if valid, 0 on error. | |
291 | * If valid, returns pointers to newly allocated GPT header and PTEs. | |
292 | */ | |
293 | static int | |
294 | is_gpt_valid(struct block_device *bdev, u64 lba, | |
295 | gpt_header **gpt, gpt_entry **ptes) | |
296 | { | |
297 | u32 crc, origcrc; | |
298 | u64 lastlba; | |
299 | ||
300 | if (!bdev || !gpt || !ptes) | |
301 | return 0; | |
302 | if (!(*gpt = alloc_read_gpt_header(bdev, lba))) | |
303 | return 0; | |
304 | ||
305 | /* Check the GUID Partition Table signature */ | |
306 | if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) { | |
d9916962 TG |
307 | pr_debug("GUID Partition Table Header signature is wrong:" |
308 | "%lld != %lld\n", | |
309 | (unsigned long long)le64_to_cpu((*gpt)->signature), | |
310 | (unsigned long long)GPT_HEADER_SIGNATURE); | |
1da177e4 LT |
311 | goto fail; |
312 | } | |
313 | ||
314 | /* Check the GUID Partition Table CRC */ | |
315 | origcrc = le32_to_cpu((*gpt)->header_crc32); | |
316 | (*gpt)->header_crc32 = 0; | |
317 | crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size)); | |
318 | ||
319 | if (crc != origcrc) { | |
d9916962 TG |
320 | pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n", |
321 | crc, origcrc); | |
1da177e4 LT |
322 | goto fail; |
323 | } | |
324 | (*gpt)->header_crc32 = cpu_to_le32(origcrc); | |
325 | ||
326 | /* Check that the my_lba entry points to the LBA that contains | |
327 | * the GUID Partition Table */ | |
328 | if (le64_to_cpu((*gpt)->my_lba) != lba) { | |
d9916962 TG |
329 | pr_debug("GPT my_lba incorrect: %lld != %lld\n", |
330 | (unsigned long long)le64_to_cpu((*gpt)->my_lba), | |
331 | (unsigned long long)lba); | |
1da177e4 LT |
332 | goto fail; |
333 | } | |
334 | ||
335 | /* Check the first_usable_lba and last_usable_lba are | |
336 | * within the disk. | |
337 | */ | |
338 | lastlba = last_lba(bdev); | |
339 | if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) { | |
d9916962 TG |
340 | pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n", |
341 | (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba), | |
342 | (unsigned long long)lastlba); | |
1da177e4 LT |
343 | goto fail; |
344 | } | |
345 | if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) { | |
d9916962 TG |
346 | pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n", |
347 | (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba), | |
348 | (unsigned long long)lastlba); | |
1da177e4 LT |
349 | goto fail; |
350 | } | |
351 | ||
352 | if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt))) | |
353 | goto fail; | |
354 | ||
355 | /* Check the GUID Partition Entry Array CRC */ | |
356 | crc = efi_crc32((const unsigned char *) (*ptes), | |
357 | le32_to_cpu((*gpt)->num_partition_entries) * | |
358 | le32_to_cpu((*gpt)->sizeof_partition_entry)); | |
359 | ||
360 | if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) { | |
d9916962 | 361 | pr_debug("GUID Partitition Entry Array CRC check failed.\n"); |
1da177e4 LT |
362 | goto fail_ptes; |
363 | } | |
364 | ||
365 | /* We're done, all's well */ | |
366 | return 1; | |
367 | ||
368 | fail_ptes: | |
369 | kfree(*ptes); | |
370 | *ptes = NULL; | |
371 | fail: | |
372 | kfree(*gpt); | |
373 | *gpt = NULL; | |
374 | return 0; | |
375 | } | |
376 | ||
377 | /** | |
378 | * is_pte_valid() - tests one PTE for validity | |
379 | * @pte is the pte to check | |
380 | * @lastlba is last lba of the disk | |
381 | * | |
382 | * Description: returns 1 if valid, 0 on error. | |
383 | */ | |
384 | static inline int | |
385 | is_pte_valid(const gpt_entry *pte, const u64 lastlba) | |
386 | { | |
387 | if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) || | |
388 | le64_to_cpu(pte->starting_lba) > lastlba || | |
389 | le64_to_cpu(pte->ending_lba) > lastlba) | |
390 | return 0; | |
391 | return 1; | |
392 | } | |
393 | ||
394 | /** | |
395 | * compare_gpts() - Search disk for valid GPT headers and PTEs | |
396 | * @pgpt is the primary GPT header | |
397 | * @agpt is the alternate GPT header | |
398 | * @lastlba is the last LBA number | |
399 | * Description: Returns nothing. Sanity checks pgpt and agpt fields | |
400 | * and prints warnings on discrepancies. | |
401 | * | |
402 | */ | |
403 | static void | |
404 | compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba) | |
405 | { | |
406 | int error_found = 0; | |
407 | if (!pgpt || !agpt) | |
408 | return; | |
409 | if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) { | |
410 | printk(KERN_WARNING | |
411 | "GPT:Primary header LBA != Alt. header alternate_lba\n"); | |
412 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
413 | (unsigned long long)le64_to_cpu(pgpt->my_lba), | |
414 | (unsigned long long)le64_to_cpu(agpt->alternate_lba)); | |
415 | error_found++; | |
416 | } | |
417 | if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) { | |
418 | printk(KERN_WARNING | |
419 | "GPT:Primary header alternate_lba != Alt. header my_lba\n"); | |
420 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
421 | (unsigned long long)le64_to_cpu(pgpt->alternate_lba), | |
422 | (unsigned long long)le64_to_cpu(agpt->my_lba)); | |
423 | error_found++; | |
424 | } | |
425 | if (le64_to_cpu(pgpt->first_usable_lba) != | |
426 | le64_to_cpu(agpt->first_usable_lba)) { | |
427 | printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n"); | |
428 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
429 | (unsigned long long)le64_to_cpu(pgpt->first_usable_lba), | |
430 | (unsigned long long)le64_to_cpu(agpt->first_usable_lba)); | |
431 | error_found++; | |
432 | } | |
433 | if (le64_to_cpu(pgpt->last_usable_lba) != | |
434 | le64_to_cpu(agpt->last_usable_lba)) { | |
435 | printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n"); | |
436 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
437 | (unsigned long long)le64_to_cpu(pgpt->last_usable_lba), | |
438 | (unsigned long long)le64_to_cpu(agpt->last_usable_lba)); | |
439 | error_found++; | |
440 | } | |
441 | if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) { | |
442 | printk(KERN_WARNING "GPT:disk_guids don't match.\n"); | |
443 | error_found++; | |
444 | } | |
445 | if (le32_to_cpu(pgpt->num_partition_entries) != | |
446 | le32_to_cpu(agpt->num_partition_entries)) { | |
447 | printk(KERN_WARNING "GPT:num_partition_entries don't match: " | |
448 | "0x%x != 0x%x\n", | |
449 | le32_to_cpu(pgpt->num_partition_entries), | |
450 | le32_to_cpu(agpt->num_partition_entries)); | |
451 | error_found++; | |
452 | } | |
453 | if (le32_to_cpu(pgpt->sizeof_partition_entry) != | |
454 | le32_to_cpu(agpt->sizeof_partition_entry)) { | |
455 | printk(KERN_WARNING | |
456 | "GPT:sizeof_partition_entry values don't match: " | |
457 | "0x%x != 0x%x\n", | |
458 | le32_to_cpu(pgpt->sizeof_partition_entry), | |
459 | le32_to_cpu(agpt->sizeof_partition_entry)); | |
460 | error_found++; | |
461 | } | |
462 | if (le32_to_cpu(pgpt->partition_entry_array_crc32) != | |
463 | le32_to_cpu(agpt->partition_entry_array_crc32)) { | |
464 | printk(KERN_WARNING | |
465 | "GPT:partition_entry_array_crc32 values don't match: " | |
466 | "0x%x != 0x%x\n", | |
467 | le32_to_cpu(pgpt->partition_entry_array_crc32), | |
468 | le32_to_cpu(agpt->partition_entry_array_crc32)); | |
469 | error_found++; | |
470 | } | |
471 | if (le64_to_cpu(pgpt->alternate_lba) != lastlba) { | |
472 | printk(KERN_WARNING | |
473 | "GPT:Primary header thinks Alt. header is not at the end of the disk.\n"); | |
474 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
475 | (unsigned long long)le64_to_cpu(pgpt->alternate_lba), | |
476 | (unsigned long long)lastlba); | |
477 | error_found++; | |
478 | } | |
479 | ||
480 | if (le64_to_cpu(agpt->my_lba) != lastlba) { | |
481 | printk(KERN_WARNING | |
482 | "GPT:Alternate GPT header not at the end of the disk.\n"); | |
483 | printk(KERN_WARNING "GPT:%lld != %lld\n", | |
484 | (unsigned long long)le64_to_cpu(agpt->my_lba), | |
485 | (unsigned long long)lastlba); | |
486 | error_found++; | |
487 | } | |
488 | ||
489 | if (error_found) | |
490 | printk(KERN_WARNING | |
491 | "GPT: Use GNU Parted to correct GPT errors.\n"); | |
492 | return; | |
493 | } | |
494 | ||
495 | /** | |
496 | * find_valid_gpt() - Search disk for valid GPT headers and PTEs | |
497 | * @bdev | |
498 | * @gpt is a GPT header ptr, filled on return. | |
499 | * @ptes is a PTEs ptr, filled on return. | |
500 | * Description: Returns 1 if valid, 0 on error. | |
501 | * If valid, returns pointers to newly allocated GPT header and PTEs. | |
502 | * Validity depends on PMBR being valid (or being overridden by the | |
503 | * 'gpt' kernel command line option) and finding either the Primary | |
504 | * GPT header and PTEs valid, or the Alternate GPT header and PTEs | |
505 | * valid. If the Primary GPT header is not valid, the Alternate GPT header | |
506 | * is not checked unless the 'gpt' kernel command line option is passed. | |
507 | * This protects against devices which misreport their size, and forces | |
508 | * the user to decide to use the Alternate GPT. | |
509 | */ | |
510 | static int | |
511 | find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes) | |
512 | { | |
513 | int good_pgpt = 0, good_agpt = 0, good_pmbr = 0; | |
514 | gpt_header *pgpt = NULL, *agpt = NULL; | |
515 | gpt_entry *pptes = NULL, *aptes = NULL; | |
4c64c30a | 516 | legacy_mbr *legacymbr; |
1da177e4 LT |
517 | u64 lastlba; |
518 | if (!bdev || !gpt || !ptes) | |
519 | return 0; | |
520 | ||
521 | lastlba = last_lba(bdev); | |
522 | if (!force_gpt) { | |
523 | /* This will be added to the EFI Spec. per Intel after v1.02. */ | |
f8314dc6 | 524 | legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL); |
1da177e4 | 525 | if (legacymbr) { |
1da177e4 LT |
526 | read_lba(bdev, 0, (u8 *) legacymbr, |
527 | sizeof (*legacymbr)); | |
4c64c30a | 528 | good_pmbr = is_pmbr_valid(legacymbr); |
1da177e4 | 529 | kfree(legacymbr); |
1da177e4 LT |
530 | } |
531 | if (!good_pmbr) | |
532 | goto fail; | |
533 | } | |
534 | ||
535 | good_pgpt = is_gpt_valid(bdev, GPT_PRIMARY_PARTITION_TABLE_LBA, | |
536 | &pgpt, &pptes); | |
537 | if (good_pgpt) | |
538 | good_agpt = is_gpt_valid(bdev, | |
539 | le64_to_cpu(pgpt->alternate_lba), | |
540 | &agpt, &aptes); | |
541 | if (!good_agpt && force_gpt) | |
542 | good_agpt = is_gpt_valid(bdev, lastlba, | |
543 | &agpt, &aptes); | |
544 | ||
545 | /* The obviously unsuccessful case */ | |
546 | if (!good_pgpt && !good_agpt) | |
547 | goto fail; | |
548 | ||
549 | compare_gpts(pgpt, agpt, lastlba); | |
550 | ||
551 | /* The good cases */ | |
552 | if (good_pgpt) { | |
553 | *gpt = pgpt; | |
554 | *ptes = pptes; | |
555 | kfree(agpt); | |
556 | kfree(aptes); | |
557 | if (!good_agpt) { | |
558 | printk(KERN_WARNING | |
559 | "Alternate GPT is invalid, " | |
560 | "using primary GPT.\n"); | |
561 | } | |
562 | return 1; | |
563 | } | |
564 | else if (good_agpt) { | |
565 | *gpt = agpt; | |
566 | *ptes = aptes; | |
567 | kfree(pgpt); | |
568 | kfree(pptes); | |
569 | printk(KERN_WARNING | |
570 | "Primary GPT is invalid, using alternate GPT.\n"); | |
571 | return 1; | |
572 | } | |
573 | ||
574 | fail: | |
575 | kfree(pgpt); | |
576 | kfree(agpt); | |
577 | kfree(pptes); | |
578 | kfree(aptes); | |
579 | *gpt = NULL; | |
580 | *ptes = NULL; | |
581 | return 0; | |
582 | } | |
583 | ||
584 | /** | |
585 | * efi_partition(struct parsed_partitions *state, struct block_device *bdev) | |
586 | * @state | |
587 | * @bdev | |
588 | * | |
589 | * Description: called from check.c, if the disk contains GPT | |
590 | * partitions, sets up partition entries in the kernel. | |
591 | * | |
592 | * If the first block on the disk is a legacy MBR, | |
593 | * it will get handled by msdos_partition(). | |
594 | * If it's a Protective MBR, we'll handle it here. | |
595 | * | |
596 | * We do not create a Linux partition for GPT, but | |
597 | * only for the actual data partitions. | |
598 | * Returns: | |
599 | * -1 if unable to read the partition table | |
600 | * 0 if this isn't our partition table | |
601 | * 1 if successful | |
602 | * | |
603 | */ | |
604 | int | |
605 | efi_partition(struct parsed_partitions *state, struct block_device *bdev) | |
606 | { | |
607 | gpt_header *gpt = NULL; | |
608 | gpt_entry *ptes = NULL; | |
609 | u32 i; | |
7d13af32 | 610 | unsigned ssz = bdev_logical_block_size(bdev) / 512; |
1da177e4 LT |
611 | |
612 | if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) { | |
613 | kfree(gpt); | |
614 | kfree(ptes); | |
615 | return 0; | |
616 | } | |
617 | ||
d9916962 | 618 | pr_debug("GUID Partition Table is valid! Yea!\n"); |
1da177e4 LT |
619 | |
620 | for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) { | |
7d13af32 KZ |
621 | u64 start = le64_to_cpu(ptes[i].starting_lba); |
622 | u64 size = le64_to_cpu(ptes[i].ending_lba) - | |
623 | le64_to_cpu(ptes[i].starting_lba) + 1ULL; | |
624 | ||
1da177e4 LT |
625 | if (!is_pte_valid(&ptes[i], last_lba(bdev))) |
626 | continue; | |
627 | ||
7d13af32 | 628 | put_partition(state, i+1, start * ssz, size * ssz); |
1da177e4 LT |
629 | |
630 | /* If this is a RAID volume, tell md */ | |
631 | if (!efi_guidcmp(ptes[i].partition_type_guid, | |
632 | PARTITION_LINUX_RAID_GUID)) | |
633 | state->parts[i+1].flags = 1; | |
634 | } | |
635 | kfree(ptes); | |
636 | kfree(gpt); | |
637 | printk("\n"); | |
638 | return 1; | |
639 | } |