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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.
7  *
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.
12  *
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.
17  *
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
21  *
22  *
23  * TODO:
24  *
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
30  *
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.
40  *
41  * Mon  Feb 04 2002 Matt Domsch <Matt_Domsch@dell.com>
42  * - Removed __PRIPTR_PREFIX - not being used
43  *
44  * Mon  Jan 14 2002 Matt Domsch <Matt_Domsch@dell.com>
45  * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
46  *
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.
52  *
53  * Wed Oct 17 2001 Matt Domsch <Matt_Domsch@dell.com>
54  * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
55  *
56  * Wed Oct 10 2001 Matt Domsch <Matt_Domsch@dell.com>
57  * - Changed function comments to DocBook style per Andreas Dilger suggestion.
58  *
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()
63  *
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.
74  *
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.
78  *
79  * Tue Dec  5 2000 Matt Domsch <Matt_Domsch@dell.com>
80  * - Moved crc32() to linux/lib, added efi_crc32().
81  *
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.
85  *
86  * Wed Oct 25 2000 Matt Domsch <Matt_Domsch@dell.com>
87  * - Fixed the last_lba() call to return the proper last block
88  *
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.
92  *
93  ************************************************************/
94 #include <linux/crc32.h>
95 #include "check.h"
96 #include "efi.h"
97 
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.
101  */
102 static int force_gpt;
103 static int __init
force_gpt_fn(char * str)104 force_gpt_fn(char *str)
105 {
106 	force_gpt = 1;
107 	return 1;
108 }
109 __setup("gpt", force_gpt_fn);
110 
111 
112 /**
113  * efi_crc32() - EFI version of crc32 function
114  * @buf: buffer to calculate crc32 of
115  * @len - length of buf
116  *
117  * Description: Returns EFI-style CRC32 value for @buf
118  *
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).
123  */
124 static inline u32
efi_crc32(const void * buf,unsigned long len)125 efi_crc32(const void *buf, unsigned long len)
126 {
127 	return (crc32(~0L, buf, len) ^ ~0L);
128 }
129 
130 /**
131  * last_lba(): return number of last logical block of device
132  * @bdev: block device
133  *
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.
138  */
139 static u64
last_lba(struct block_device * bdev)140 last_lba(struct block_device *bdev)
141 {
142 	if (!bdev || !bdev->bd_inode)
143 		return 0;
144 	return (bdev->bd_inode->i_size >> 9) - 1ULL;
145 }
146 
147 static inline int
pmbr_part_valid(struct partition * part)148 pmbr_part_valid(struct partition *part)
149 {
150         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
151             le32_to_cpu(part->start_sect) == 1UL)
152                 return 1;
153         return 0;
154 }
155 
156 /**
157  * is_pmbr_valid(): test Protective MBR for validity
158  * @mbr: pointer to a legacy mbr structure
159  *
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
164  */
165 static int
is_pmbr_valid(legacy_mbr * mbr)166 is_pmbr_valid(legacy_mbr *mbr)
167 {
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;
175 }
176 
177 /**
178  * read_lba(): Read bytes from disk, starting at given LBA
179  * @bdev
180  * @lba
181  * @buffer
182  * @size_t
183  *
184  * Description:  Reads @count bytes from @bdev into @buffer.
185  * Returns number of bytes read on success, 0 on error.
186  */
187 static size_t
read_lba(struct block_device * bdev,u64 lba,u8 * buffer,size_t count)188 read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
189 {
190 	size_t totalreadcount = 0;
191 
192 	if (!bdev || !buffer || lba > last_lba(bdev))
193                 return 0;
194 
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;
208 	}
209 	return totalreadcount;
210 }
211 
212 /**
213  * alloc_read_gpt_entries(): reads partition entries from disk
214  * @bdev
215  * @gpt - GPT header
216  *
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!
220  */
221 static gpt_entry *
alloc_read_gpt_entries(struct block_device * bdev,gpt_header * gpt)222 alloc_read_gpt_entries(struct block_device *bdev, gpt_header *gpt)
223 {
224 	size_t count;
225 	gpt_entry *pte;
226 	if (!bdev || !gpt)
227 		return NULL;
228 
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;
236 
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;
243 	}
244 	return pte;
245 }
246 
247 /**
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
251  *
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.
255  */
256 static gpt_header *
alloc_read_gpt_header(struct block_device * bdev,u64 lba)257 alloc_read_gpt_header(struct block_device *bdev, u64 lba)
258 {
259 	gpt_header *gpt;
260 	if (!bdev)
261 		return NULL;
262 
263 	gpt = kzalloc(sizeof (gpt_header), GFP_KERNEL);
264 	if (!gpt)
265 		return NULL;
266 
267 	if (read_lba(bdev, lba, (u8 *) gpt,
268 		     sizeof (gpt_header)) < sizeof (gpt_header)) {
269 		kfree(gpt);
270                 gpt=NULL;
271 		return NULL;
272 	}
273 
274 	return gpt;
275 }
276 
277 /**
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.
283  *
284  * Description: returns 1 if valid,  0 on error.
285  * If valid, returns pointers to newly allocated GPT header and PTEs.
286  */
287 static int
is_gpt_valid(struct block_device * bdev,u64 lba,gpt_header ** gpt,gpt_entry ** ptes)288 is_gpt_valid(struct block_device *bdev, u64 lba,
289 	     gpt_header **gpt, gpt_entry **ptes)
290 {
291 	u32 crc, origcrc;
292 	u64 lastlba;
293 
294 	if (!bdev || !gpt || !ptes)
295 		return 0;
296 	if (!(*gpt = alloc_read_gpt_header(bdev, lba)))
297 		return 0;
298 
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;
306 	}
307 
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));
312 
313 	if (crc != origcrc) {
314 		pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
315 			 crc, origcrc);
316 		goto fail;
317 	}
318 	(*gpt)->header_crc32 = cpu_to_le32(origcrc);
319 
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;
327 	}
328 
329 	/* Check the first_usable_lba and last_usable_lba are
330 	 * within the disk.
331 	 */
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;
338 	}
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;
344 	}
345 
346 	if (!(*ptes = alloc_read_gpt_entries(bdev, *gpt)))
347 		goto fail;
348 
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));
353 
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;
357 	}
358 
359 	/* We're done, all's well */
360 	return 1;
361 
362  fail_ptes:
363 	kfree(*ptes);
364 	*ptes = NULL;
365  fail:
366 	kfree(*gpt);
367 	*gpt = NULL;
368 	return 0;
369 }
370 
371 /**
372  * is_pte_valid() - tests one PTE for validity
373  * @pte is the pte to check
374  * @lastlba is last lba of the disk
375  *
376  * Description: returns 1 if valid,  0 on error.
377  */
378 static inline int
is_pte_valid(const gpt_entry * pte,const u64 lastlba)379 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
380 {
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;
386 }
387 
388 /**
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.
395  *
396  */
397 static void
compare_gpts(gpt_header * pgpt,gpt_header * agpt,u64 lastlba)398 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
399 {
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++;
410 	}
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++;
418 	}
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++;
426 	}
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++;
434 	}
435 	if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
436 		printk(KERN_WARNING "GPT:disk_guids don't match.\n");
437 		error_found++;
438 	}
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++;
446 	}
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++;
455 	}
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++;
464 	}
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++;
472 	}
473 
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++;
481 	}
482 
483 	if (error_found)
484 		printk(KERN_WARNING
485 		       "GPT: Use GNU Parted to correct GPT errors.\n");
486 	return;
487 }
488 
489 /**
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.
503  */
504 static int
find_valid_gpt(struct block_device * bdev,gpt_header ** gpt,gpt_entry ** ptes)505 find_valid_gpt(struct block_device *bdev, gpt_header **gpt, gpt_entry **ptes)
506 {
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;
514 
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);
524                 }
525                 if (!good_pmbr)
526                         goto fail;
527         }
528 
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);
538 
539         /* The obviously unsuccessful case */
540         if (!good_pgpt && !good_agpt)
541                 goto fail;
542 
543         compare_gpts(pgpt, agpt, lastlba);
544 
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");
555                 }
556                 return 1;
557         }
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;
566         }
567 
568  fail:
569         kfree(pgpt);
570         kfree(agpt);
571         kfree(pptes);
572         kfree(aptes);
573         *gpt = NULL;
574         *ptes = NULL;
575         return 0;
576 }
577 
578 /**
579  * efi_partition(struct parsed_partitions *state, struct block_device *bdev)
580  * @state
581  * @bdev
582  *
583  * Description: called from check.c, if the disk contains GPT
584  * partitions, sets up partition entries in the kernel.
585  *
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.
589  *
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
596  *
597  */
598 int
efi_partition(struct parsed_partitions * state,struct block_device * bdev)599 efi_partition(struct parsed_partitions *state, struct block_device *bdev)
600 {
601 	gpt_header *gpt = NULL;
602 	gpt_entry *ptes = NULL;
603 	u32 i;
604 
605 	if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
606 		kfree(gpt);
607 		kfree(ptes);
608 		return 0;
609 	}
610 
611 	pr_debug("GUID Partition Table is valid!  Yea!\n");
612 
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;
616 
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));
621 
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;
626 	}
627 	kfree(ptes);
628 	kfree(gpt);
629 	printk("\n");
630 	return 1;
631 }
632