xref: /linux/block/partitions/efi.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /************************************************************
2  * EFI GUID Partition Table handling
3  *
4  * http://www.uefi.org/specs/
5  * http://www.intel.com/technology/efi/
6  *
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  ************************************************************/
96 #include <linux/crc32.h>
97 #include <linux/ctype.h>
98 #include <linux/math64.h>
99 #include <linux/slab.h>
100 #include "check.h"
101 #include "efi.h"
102 
103 /* This allows a kernel command line option 'gpt' to override
104  * the test for invalid PMBR.  Not __initdata because reloading
105  * the partition tables happens after init too.
106  */
107 static int force_gpt;
108 static int __init
109 force_gpt_fn(char *str)
110 {
111 	force_gpt = 1;
112 	return 1;
113 }
114 __setup("gpt", force_gpt_fn);
115 
116 
117 /**
118  * efi_crc32() - EFI version of crc32 function
119  * @buf: buffer to calculate crc32 of
120  * @len - length of buf
121  *
122  * Description: Returns EFI-style CRC32 value for @buf
123  *
124  * This function uses the little endian Ethernet polynomial
125  * but seeds the function with ~0, and xor's with ~0 at the end.
126  * Note, the EFI Specification, v1.02, has a reference to
127  * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
128  */
129 static inline u32
130 efi_crc32(const void *buf, unsigned long len)
131 {
132 	return (crc32(~0L, buf, len) ^ ~0L);
133 }
134 
135 /**
136  * last_lba(): return number of last logical block of device
137  * @bdev: block device
138  *
139  * Description: Returns last LBA value on success, 0 on error.
140  * This is stored (by sd and ide-geometry) in
141  *  the part[0] entry for this disk, and is the number of
142  *  physical sectors available on the disk.
143  */
144 static u64 last_lba(struct block_device *bdev)
145 {
146 	if (!bdev || !bdev->bd_inode)
147 		return 0;
148 	return div_u64(bdev->bd_inode->i_size,
149 		       bdev_logical_block_size(bdev)) - 1ULL;
150 }
151 
152 static inline int
153 pmbr_part_valid(struct partition *part)
154 {
155         if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
156             le32_to_cpu(part->start_sect) == 1UL)
157                 return 1;
158         return 0;
159 }
160 
161 /**
162  * is_pmbr_valid(): test Protective MBR for validity
163  * @mbr: pointer to a legacy mbr structure
164  *
165  * Description: Returns 1 if PMBR is valid, 0 otherwise.
166  * Validity depends on two things:
167  *  1) MSDOS signature is in the last two bytes of the MBR
168  *  2) One partition of type 0xEE is found
169  */
170 static int
171 is_pmbr_valid(legacy_mbr *mbr)
172 {
173 	int i;
174 	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
175                 return 0;
176 	for (i = 0; i < 4; i++)
177 		if (pmbr_part_valid(&mbr->partition_record[i]))
178                         return 1;
179 	return 0;
180 }
181 
182 /**
183  * read_lba(): Read bytes from disk, starting at given LBA
184  * @state
185  * @lba
186  * @buffer
187  * @size_t
188  *
189  * Description: Reads @count bytes from @state->bdev into @buffer.
190  * Returns number of bytes read on success, 0 on error.
191  */
192 static size_t read_lba(struct parsed_partitions *state,
193 		       u64 lba, u8 *buffer, size_t count)
194 {
195 	size_t totalreadcount = 0;
196 	struct block_device *bdev = state->bdev;
197 	sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
198 
199 	if (!buffer || lba > last_lba(bdev))
200                 return 0;
201 
202 	while (count) {
203 		int copied = 512;
204 		Sector sect;
205 		unsigned char *data = read_part_sector(state, n++, &sect);
206 		if (!data)
207 			break;
208 		if (copied > count)
209 			copied = count;
210 		memcpy(buffer, data, copied);
211 		put_dev_sector(sect);
212 		buffer += copied;
213 		totalreadcount +=copied;
214 		count -= copied;
215 	}
216 	return totalreadcount;
217 }
218 
219 /**
220  * alloc_read_gpt_entries(): reads partition entries from disk
221  * @state
222  * @gpt - GPT header
223  *
224  * Description: Returns ptes on success,  NULL on error.
225  * Allocates space for PTEs based on information found in @gpt.
226  * Notes: remember to free pte when you're done!
227  */
228 static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
229 					 gpt_header *gpt)
230 {
231 	size_t count;
232 	gpt_entry *pte;
233 
234 	if (!gpt)
235 		return NULL;
236 
237 	count = le32_to_cpu(gpt->num_partition_entries) *
238                 le32_to_cpu(gpt->sizeof_partition_entry);
239 	if (!count)
240 		return NULL;
241 	pte = kzalloc(count, GFP_KERNEL);
242 	if (!pte)
243 		return NULL;
244 
245 	if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
246                      (u8 *) pte,
247 		     count) < count) {
248 		kfree(pte);
249                 pte=NULL;
250 		return NULL;
251 	}
252 	return pte;
253 }
254 
255 /**
256  * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
257  * @state
258  * @lba is the Logical Block Address of the partition table
259  *
260  * Description: returns GPT header on success, NULL on error.   Allocates
261  * and fills a GPT header starting at @ from @state->bdev.
262  * Note: remember to free gpt when finished with it.
263  */
264 static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
265 					 u64 lba)
266 {
267 	gpt_header *gpt;
268 	unsigned ssz = bdev_logical_block_size(state->bdev);
269 
270 	gpt = kzalloc(ssz, GFP_KERNEL);
271 	if (!gpt)
272 		return NULL;
273 
274 	if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {
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  * @state
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 is_gpt_valid(struct parsed_partitions *state, u64 lba,
294 			gpt_header **gpt, gpt_entry **ptes)
295 {
296 	u32 crc, origcrc;
297 	u64 lastlba;
298 
299 	if (!ptes)
300 		return 0;
301 	if (!(*gpt = alloc_read_gpt_header(state, lba)))
302 		return 0;
303 
304 	/* Check the GUID Partition Table signature */
305 	if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
306 		pr_debug("GUID Partition Table Header signature is wrong:"
307 			 "%lld != %lld\n",
308 			 (unsigned long long)le64_to_cpu((*gpt)->signature),
309 			 (unsigned long long)GPT_HEADER_SIGNATURE);
310 		goto fail;
311 	}
312 
313 	/* Check the GUID Partition Table header size */
314 	if (le32_to_cpu((*gpt)->header_size) >
315 			bdev_logical_block_size(state->bdev)) {
316 		pr_debug("GUID Partition Table Header size is wrong: %u > %u\n",
317 			le32_to_cpu((*gpt)->header_size),
318 			bdev_logical_block_size(state->bdev));
319 		goto fail;
320 	}
321 
322 	/* Check the GUID Partition Table CRC */
323 	origcrc = le32_to_cpu((*gpt)->header_crc32);
324 	(*gpt)->header_crc32 = 0;
325 	crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
326 
327 	if (crc != origcrc) {
328 		pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
329 			 crc, origcrc);
330 		goto fail;
331 	}
332 	(*gpt)->header_crc32 = cpu_to_le32(origcrc);
333 
334 	/* Check that the my_lba entry points to the LBA that contains
335 	 * the GUID Partition Table */
336 	if (le64_to_cpu((*gpt)->my_lba) != lba) {
337 		pr_debug("GPT my_lba incorrect: %lld != %lld\n",
338 			 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
339 			 (unsigned long long)lba);
340 		goto fail;
341 	}
342 
343 	/* Check the first_usable_lba and last_usable_lba are
344 	 * within the disk.
345 	 */
346 	lastlba = last_lba(state->bdev);
347 	if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
348 		pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
349 			 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
350 			 (unsigned long long)lastlba);
351 		goto fail;
352 	}
353 	if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
354 		pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
355 			 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
356 			 (unsigned long long)lastlba);
357 		goto fail;
358 	}
359 
360 	/* Check that sizeof_partition_entry has the correct value */
361 	if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {
362 		pr_debug("GUID Partitition Entry Size check failed.\n");
363 		goto fail;
364 	}
365 
366 	if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
367 		goto fail;
368 
369 	/* Check the GUID Partition Entry Array CRC */
370 	crc = efi_crc32((const unsigned char *) (*ptes),
371 			le32_to_cpu((*gpt)->num_partition_entries) *
372 			le32_to_cpu((*gpt)->sizeof_partition_entry));
373 
374 	if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
375 		pr_debug("GUID Partitition Entry Array CRC check failed.\n");
376 		goto fail_ptes;
377 	}
378 
379 	/* We're done, all's well */
380 	return 1;
381 
382  fail_ptes:
383 	kfree(*ptes);
384 	*ptes = NULL;
385  fail:
386 	kfree(*gpt);
387 	*gpt = NULL;
388 	return 0;
389 }
390 
391 /**
392  * is_pte_valid() - tests one PTE for validity
393  * @pte is the pte to check
394  * @lastlba is last lba of the disk
395  *
396  * Description: returns 1 if valid,  0 on error.
397  */
398 static inline int
399 is_pte_valid(const gpt_entry *pte, const u64 lastlba)
400 {
401 	if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
402 	    le64_to_cpu(pte->starting_lba) > lastlba         ||
403 	    le64_to_cpu(pte->ending_lba)   > lastlba)
404 		return 0;
405 	return 1;
406 }
407 
408 /**
409  * compare_gpts() - Search disk for valid GPT headers and PTEs
410  * @pgpt is the primary GPT header
411  * @agpt is the alternate GPT header
412  * @lastlba is the last LBA number
413  * Description: Returns nothing.  Sanity checks pgpt and agpt fields
414  * and prints warnings on discrepancies.
415  *
416  */
417 static void
418 compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
419 {
420 	int error_found = 0;
421 	if (!pgpt || !agpt)
422 		return;
423 	if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
424 		printk(KERN_WARNING
425 		       "GPT:Primary header LBA != Alt. header alternate_lba\n");
426 		printk(KERN_WARNING "GPT:%lld != %lld\n",
427 		       (unsigned long long)le64_to_cpu(pgpt->my_lba),
428                        (unsigned long long)le64_to_cpu(agpt->alternate_lba));
429 		error_found++;
430 	}
431 	if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
432 		printk(KERN_WARNING
433 		       "GPT:Primary header alternate_lba != Alt. header my_lba\n");
434 		printk(KERN_WARNING "GPT:%lld != %lld\n",
435 		       (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
436                        (unsigned long long)le64_to_cpu(agpt->my_lba));
437 		error_found++;
438 	}
439 	if (le64_to_cpu(pgpt->first_usable_lba) !=
440             le64_to_cpu(agpt->first_usable_lba)) {
441 		printk(KERN_WARNING "GPT:first_usable_lbas don't match.\n");
442 		printk(KERN_WARNING "GPT:%lld != %lld\n",
443 		       (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
444                        (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
445 		error_found++;
446 	}
447 	if (le64_to_cpu(pgpt->last_usable_lba) !=
448             le64_to_cpu(agpt->last_usable_lba)) {
449 		printk(KERN_WARNING "GPT:last_usable_lbas don't match.\n");
450 		printk(KERN_WARNING "GPT:%lld != %lld\n",
451 		       (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
452                        (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
453 		error_found++;
454 	}
455 	if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
456 		printk(KERN_WARNING "GPT:disk_guids don't match.\n");
457 		error_found++;
458 	}
459 	if (le32_to_cpu(pgpt->num_partition_entries) !=
460             le32_to_cpu(agpt->num_partition_entries)) {
461 		printk(KERN_WARNING "GPT:num_partition_entries don't match: "
462 		       "0x%x != 0x%x\n",
463 		       le32_to_cpu(pgpt->num_partition_entries),
464 		       le32_to_cpu(agpt->num_partition_entries));
465 		error_found++;
466 	}
467 	if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
468             le32_to_cpu(agpt->sizeof_partition_entry)) {
469 		printk(KERN_WARNING
470 		       "GPT:sizeof_partition_entry values don't match: "
471 		       "0x%x != 0x%x\n",
472                        le32_to_cpu(pgpt->sizeof_partition_entry),
473 		       le32_to_cpu(agpt->sizeof_partition_entry));
474 		error_found++;
475 	}
476 	if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
477             le32_to_cpu(agpt->partition_entry_array_crc32)) {
478 		printk(KERN_WARNING
479 		       "GPT:partition_entry_array_crc32 values don't match: "
480 		       "0x%x != 0x%x\n",
481                        le32_to_cpu(pgpt->partition_entry_array_crc32),
482 		       le32_to_cpu(agpt->partition_entry_array_crc32));
483 		error_found++;
484 	}
485 	if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
486 		printk(KERN_WARNING
487 		       "GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
488 		printk(KERN_WARNING "GPT:%lld != %lld\n",
489 			(unsigned long long)le64_to_cpu(pgpt->alternate_lba),
490 			(unsigned long long)lastlba);
491 		error_found++;
492 	}
493 
494 	if (le64_to_cpu(agpt->my_lba) != lastlba) {
495 		printk(KERN_WARNING
496 		       "GPT:Alternate GPT header not at the end of the disk.\n");
497 		printk(KERN_WARNING "GPT:%lld != %lld\n",
498 			(unsigned long long)le64_to_cpu(agpt->my_lba),
499 			(unsigned long long)lastlba);
500 		error_found++;
501 	}
502 
503 	if (error_found)
504 		printk(KERN_WARNING
505 		       "GPT: Use GNU Parted to correct GPT errors.\n");
506 	return;
507 }
508 
509 /**
510  * find_valid_gpt() - Search disk for valid GPT headers and PTEs
511  * @state
512  * @gpt is a GPT header ptr, filled on return.
513  * @ptes is a PTEs ptr, filled on return.
514  * Description: Returns 1 if valid, 0 on error.
515  * If valid, returns pointers to newly allocated GPT header and PTEs.
516  * Validity depends on PMBR being valid (or being overridden by the
517  * 'gpt' kernel command line option) and finding either the Primary
518  * GPT header and PTEs valid, or the Alternate GPT header and PTEs
519  * valid.  If the Primary GPT header is not valid, the Alternate GPT header
520  * is not checked unless the 'gpt' kernel command line option is passed.
521  * This protects against devices which misreport their size, and forces
522  * the user to decide to use the Alternate GPT.
523  */
524 static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
525 			  gpt_entry **ptes)
526 {
527 	int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
528 	gpt_header *pgpt = NULL, *agpt = NULL;
529 	gpt_entry *pptes = NULL, *aptes = NULL;
530 	legacy_mbr *legacymbr;
531 	u64 lastlba;
532 
533 	if (!ptes)
534 		return 0;
535 
536 	lastlba = last_lba(state->bdev);
537         if (!force_gpt) {
538                 /* This will be added to the EFI Spec. per Intel after v1.02. */
539                 legacymbr = kzalloc(sizeof (*legacymbr), GFP_KERNEL);
540                 if (legacymbr) {
541                         read_lba(state, 0, (u8 *) legacymbr,
542 				 sizeof (*legacymbr));
543                         good_pmbr = is_pmbr_valid(legacymbr);
544                         kfree(legacymbr);
545                 }
546                 if (!good_pmbr)
547                         goto fail;
548         }
549 
550 	good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
551 				 &pgpt, &pptes);
552         if (good_pgpt)
553 		good_agpt = is_gpt_valid(state,
554 					 le64_to_cpu(pgpt->alternate_lba),
555 					 &agpt, &aptes);
556         if (!good_agpt && force_gpt)
557                 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
558 
559         /* The obviously unsuccessful case */
560         if (!good_pgpt && !good_agpt)
561                 goto fail;
562 
563         compare_gpts(pgpt, agpt, lastlba);
564 
565         /* The good cases */
566         if (good_pgpt) {
567                 *gpt  = pgpt;
568                 *ptes = pptes;
569                 kfree(agpt);
570                 kfree(aptes);
571                 if (!good_agpt) {
572                         printk(KERN_WARNING
573 			       "Alternate GPT is invalid, "
574                                "using primary GPT.\n");
575                 }
576                 return 1;
577         }
578         else if (good_agpt) {
579                 *gpt  = agpt;
580                 *ptes = aptes;
581                 kfree(pgpt);
582                 kfree(pptes);
583                 printk(KERN_WARNING
584                        "Primary GPT is invalid, using alternate GPT.\n");
585                 return 1;
586         }
587 
588  fail:
589         kfree(pgpt);
590         kfree(agpt);
591         kfree(pptes);
592         kfree(aptes);
593         *gpt = NULL;
594         *ptes = NULL;
595         return 0;
596 }
597 
598 /**
599  * efi_partition(struct parsed_partitions *state)
600  * @state
601  *
602  * Description: called from check.c, if the disk contains GPT
603  * partitions, sets up partition entries in the kernel.
604  *
605  * If the first block on the disk is a legacy MBR,
606  * it will get handled by msdos_partition().
607  * If it's a Protective MBR, we'll handle it here.
608  *
609  * We do not create a Linux partition for GPT, but
610  * only for the actual data partitions.
611  * Returns:
612  * -1 if unable to read the partition table
613  *  0 if this isn't our partition table
614  *  1 if successful
615  *
616  */
617 int efi_partition(struct parsed_partitions *state)
618 {
619 	gpt_header *gpt = NULL;
620 	gpt_entry *ptes = NULL;
621 	u32 i;
622 	unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
623 
624 	if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
625 		kfree(gpt);
626 		kfree(ptes);
627 		return 0;
628 	}
629 
630 	pr_debug("GUID Partition Table is valid!  Yea!\n");
631 
632 	for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
633 		struct partition_meta_info *info;
634 		unsigned label_count = 0;
635 		unsigned label_max;
636 		u64 start = le64_to_cpu(ptes[i].starting_lba);
637 		u64 size = le64_to_cpu(ptes[i].ending_lba) -
638 			   le64_to_cpu(ptes[i].starting_lba) + 1ULL;
639 
640 		if (!is_pte_valid(&ptes[i], last_lba(state->bdev)))
641 			continue;
642 
643 		put_partition(state, i+1, start * ssz, size * ssz);
644 
645 		/* If this is a RAID volume, tell md */
646 		if (!efi_guidcmp(ptes[i].partition_type_guid,
647 				 PARTITION_LINUX_RAID_GUID))
648 			state->parts[i + 1].flags = ADDPART_FLAG_RAID;
649 
650 		info = &state->parts[i + 1].info;
651 		efi_guid_unparse(&ptes[i].unique_partition_guid, info->uuid);
652 
653 		/* Naively convert UTF16-LE to 7 bits. */
654 		label_max = min(sizeof(info->volname) - 1,
655 				sizeof(ptes[i].partition_name));
656 		info->volname[label_max] = 0;
657 		while (label_count < label_max) {
658 			u8 c = ptes[i].partition_name[label_count] & 0xff;
659 			if (c && !isprint(c))
660 				c = '!';
661 			info->volname[label_count] = c;
662 			label_count++;
663 		}
664 		state->parts[i + 1].has_info = true;
665 	}
666 	kfree(ptes);
667 	kfree(gpt);
668 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
669 	return 1;
670 }
671