xref: /openbmc/u-boot/disk/part_efi.c (revision fc5ad477)
1 /*
2  * Copyright (C) 2008 RuggedCom, Inc.
3  * Richard Retanubun <RichardRetanubun@RuggedCom.com>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 /*
9  * NOTE:
10  *   when CONFIG_SYS_64BIT_LBA is not defined, lbaint_t is 32 bits; this
11  *   limits the maximum size of addressable storage to < 2 Terra Bytes
12  */
13 #include <asm/unaligned.h>
14 #include <common.h>
15 #include <command.h>
16 #include <ide.h>
17 #include <inttypes.h>
18 #include <malloc.h>
19 #include <memalign.h>
20 #include <part_efi.h>
21 #include <linux/ctype.h>
22 
23 DECLARE_GLOBAL_DATA_PTR;
24 
25 #ifdef HAVE_BLOCK_DEVICE
26 /**
27  * efi_crc32() - EFI version of crc32 function
28  * @buf: buffer to calculate crc32 of
29  * @len - length of buf
30  *
31  * Description: Returns EFI-style CRC32 value for @buf
32  */
33 static inline u32 efi_crc32(const void *buf, u32 len)
34 {
35 	return crc32(0, buf, len);
36 }
37 
38 /*
39  * Private function prototypes
40  */
41 
42 static int pmbr_part_valid(struct partition *part);
43 static int is_pmbr_valid(legacy_mbr * mbr);
44 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
45 				gpt_header *pgpt_head, gpt_entry **pgpt_pte);
46 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
47 				gpt_header * pgpt_head);
48 static int is_pte_valid(gpt_entry * pte);
49 
50 static char *print_efiname(gpt_entry *pte)
51 {
52 	static char name[PARTNAME_SZ + 1];
53 	int i;
54 	for (i = 0; i < PARTNAME_SZ; i++) {
55 		u8 c;
56 		c = pte->partition_name[i] & 0xff;
57 		c = (c && !isprint(c)) ? '.' : c;
58 		name[i] = c;
59 	}
60 	name[PARTNAME_SZ] = 0;
61 	return name;
62 }
63 
64 static efi_guid_t system_guid = PARTITION_SYSTEM_GUID;
65 
66 static inline int is_bootable(gpt_entry *p)
67 {
68 	return p->attributes.fields.legacy_bios_bootable ||
69 		!memcmp(&(p->partition_type_guid), &system_guid,
70 			sizeof(efi_guid_t));
71 }
72 
73 static int validate_gpt_header(gpt_header *gpt_h, lbaint_t lba,
74 		lbaint_t lastlba)
75 {
76 	uint32_t crc32_backup = 0;
77 	uint32_t calc_crc32;
78 
79 	/* Check the GPT header signature */
80 	if (le64_to_cpu(gpt_h->signature) != GPT_HEADER_SIGNATURE) {
81 		printf("%s signature is wrong: 0x%llX != 0x%llX\n",
82 		       "GUID Partition Table Header",
83 		       le64_to_cpu(gpt_h->signature),
84 		       GPT_HEADER_SIGNATURE);
85 		return -1;
86 	}
87 
88 	/* Check the GUID Partition Table CRC */
89 	memcpy(&crc32_backup, &gpt_h->header_crc32, sizeof(crc32_backup));
90 	memset(&gpt_h->header_crc32, 0, sizeof(gpt_h->header_crc32));
91 
92 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
93 		le32_to_cpu(gpt_h->header_size));
94 
95 	memcpy(&gpt_h->header_crc32, &crc32_backup, sizeof(crc32_backup));
96 
97 	if (calc_crc32 != le32_to_cpu(crc32_backup)) {
98 		printf("%s CRC is wrong: 0x%x != 0x%x\n",
99 		       "GUID Partition Table Header",
100 		       le32_to_cpu(crc32_backup), calc_crc32);
101 		return -1;
102 	}
103 
104 	/*
105 	 * Check that the my_lba entry points to the LBA that contains the GPT
106 	 */
107 	if (le64_to_cpu(gpt_h->my_lba) != lba) {
108 		printf("GPT: my_lba incorrect: %llX != " LBAF "\n",
109 		       le64_to_cpu(gpt_h->my_lba),
110 		       lba);
111 		return -1;
112 	}
113 
114 	/*
115 	 * Check that the first_usable_lba and that the last_usable_lba are
116 	 * within the disk.
117 	 */
118 	if (le64_to_cpu(gpt_h->first_usable_lba) > lastlba) {
119 		printf("GPT: first_usable_lba incorrect: %llX > " LBAF "\n",
120 		       le64_to_cpu(gpt_h->first_usable_lba), lastlba);
121 		return -1;
122 	}
123 	if (le64_to_cpu(gpt_h->last_usable_lba) > lastlba) {
124 		printf("GPT: last_usable_lba incorrect: %llX > " LBAF "\n",
125 		       le64_to_cpu(gpt_h->last_usable_lba), lastlba);
126 		return -1;
127 	}
128 
129 	debug("GPT: first_usable_lba: %llX last_usable_lba: %llX last lba: "
130 	      LBAF "\n", le64_to_cpu(gpt_h->first_usable_lba),
131 	      le64_to_cpu(gpt_h->last_usable_lba), lastlba);
132 
133 	return 0;
134 }
135 
136 static int validate_gpt_entries(gpt_header *gpt_h, gpt_entry *gpt_e)
137 {
138 	uint32_t calc_crc32;
139 
140 	/* Check the GUID Partition Table Entry Array CRC */
141 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
142 		le32_to_cpu(gpt_h->num_partition_entries) *
143 		le32_to_cpu(gpt_h->sizeof_partition_entry));
144 
145 	if (calc_crc32 != le32_to_cpu(gpt_h->partition_entry_array_crc32)) {
146 		printf("%s: 0x%x != 0x%x\n",
147 		       "GUID Partition Table Entry Array CRC is wrong",
148 		       le32_to_cpu(gpt_h->partition_entry_array_crc32),
149 		       calc_crc32);
150 		return -1;
151 	}
152 
153 	return 0;
154 }
155 
156 static void prepare_backup_gpt_header(gpt_header *gpt_h)
157 {
158 	uint32_t calc_crc32;
159 	uint64_t val;
160 
161 	/* recalculate the values for the Backup GPT Header */
162 	val = le64_to_cpu(gpt_h->my_lba);
163 	gpt_h->my_lba = gpt_h->alternate_lba;
164 	gpt_h->alternate_lba = cpu_to_le64(val);
165 	gpt_h->partition_entry_lba =
166 			cpu_to_le64(le64_to_cpu(gpt_h->last_usable_lba) + 1);
167 	gpt_h->header_crc32 = 0;
168 
169 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
170 			       le32_to_cpu(gpt_h->header_size));
171 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
172 }
173 
174 #ifdef CONFIG_EFI_PARTITION
175 /*
176  * Public Functions (include/part.h)
177  */
178 
179 void print_part_efi(block_dev_desc_t * dev_desc)
180 {
181 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
182 	gpt_entry *gpt_pte = NULL;
183 	int i = 0;
184 	char uuid[37];
185 	unsigned char *uuid_bin;
186 
187 	if (!dev_desc) {
188 		printf("%s: Invalid Argument(s)\n", __func__);
189 		return;
190 	}
191 	/* This function validates AND fills in the GPT header and PTE */
192 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
193 			 gpt_head, &gpt_pte) != 1) {
194 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
195 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
196 				 gpt_head, &gpt_pte) != 1) {
197 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
198 			       __func__);
199 			return;
200 		} else {
201 			printf("%s: ***        Using Backup GPT ***\n",
202 			       __func__);
203 		}
204 	}
205 
206 	debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
207 
208 	printf("Part\tStart LBA\tEnd LBA\t\tName\n");
209 	printf("\tAttributes\n");
210 	printf("\tType GUID\n");
211 	printf("\tPartition GUID\n");
212 
213 	for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
214 		/* Stop at the first non valid PTE */
215 		if (!is_pte_valid(&gpt_pte[i]))
216 			break;
217 
218 		printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
219 			le64_to_cpu(gpt_pte[i].starting_lba),
220 			le64_to_cpu(gpt_pte[i].ending_lba),
221 			print_efiname(&gpt_pte[i]));
222 		printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
223 		uuid_bin = (unsigned char *)gpt_pte[i].partition_type_guid.b;
224 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
225 		printf("\ttype:\t%s\n", uuid);
226 		uuid_bin = (unsigned char *)gpt_pte[i].unique_partition_guid.b;
227 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
228 		printf("\tguid:\t%s\n", uuid);
229 	}
230 
231 	/* Remember to free pte */
232 	free(gpt_pte);
233 	return;
234 }
235 
236 int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
237 				disk_partition_t * info)
238 {
239 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
240 	gpt_entry *gpt_pte = NULL;
241 
242 	/* "part" argument must be at least 1 */
243 	if (!dev_desc || !info || part < 1) {
244 		printf("%s: Invalid Argument(s)\n", __func__);
245 		return -1;
246 	}
247 
248 	/* This function validates AND fills in the GPT header and PTE */
249 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
250 			gpt_head, &gpt_pte) != 1) {
251 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
252 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
253 				 gpt_head, &gpt_pte) != 1) {
254 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
255 			       __func__);
256 			return -1;
257 		} else {
258 			printf("%s: ***        Using Backup GPT ***\n",
259 			       __func__);
260 		}
261 	}
262 
263 	if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
264 	    !is_pte_valid(&gpt_pte[part - 1])) {
265 		debug("%s: *** ERROR: Invalid partition number %d ***\n",
266 			__func__, part);
267 		free(gpt_pte);
268 		return -1;
269 	}
270 
271 	/* The 'lbaint_t' casting may limit the maximum disk size to 2 TB */
272 	info->start = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].starting_lba);
273 	/* The ending LBA is inclusive, to calculate size, add 1 to it */
274 	info->size = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1
275 		     - info->start;
276 	info->blksz = dev_desc->blksz;
277 
278 	sprintf((char *)info->name, "%s",
279 			print_efiname(&gpt_pte[part - 1]));
280 	sprintf((char *)info->type, "U-Boot");
281 	info->bootable = is_bootable(&gpt_pte[part - 1]);
282 #ifdef CONFIG_PARTITION_UUIDS
283 	uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid,
284 			UUID_STR_FORMAT_GUID);
285 #endif
286 
287 	debug("%s: start 0x" LBAF ", size 0x" LBAF ", name %s\n", __func__,
288 	      info->start, info->size, info->name);
289 
290 	/* Remember to free pte */
291 	free(gpt_pte);
292 	return 0;
293 }
294 
295 int get_partition_info_efi_by_name(block_dev_desc_t *dev_desc,
296 	const char *name, disk_partition_t *info)
297 {
298 	int ret;
299 	int i;
300 	for (i = 1; i < GPT_ENTRY_NUMBERS; i++) {
301 		ret = get_partition_info_efi(dev_desc, i, info);
302 		if (ret != 0) {
303 			/* no more entries in table */
304 			return -1;
305 		}
306 		if (strcmp(name, (const char *)info->name) == 0) {
307 			/* matched */
308 			return 0;
309 		}
310 	}
311 	return -2;
312 }
313 
314 int test_part_efi(block_dev_desc_t * dev_desc)
315 {
316 	ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);
317 
318 	/* Read legacy MBR from block 0 and validate it */
319 	if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)legacymbr) != 1)
320 		|| (is_pmbr_valid(legacymbr) != 1)) {
321 		return -1;
322 	}
323 	return 0;
324 }
325 
326 /**
327  * set_protective_mbr(): Set the EFI protective MBR
328  * @param dev_desc - block device descriptor
329  *
330  * @return - zero on success, otherwise error
331  */
332 static int set_protective_mbr(block_dev_desc_t *dev_desc)
333 {
334 	/* Setup the Protective MBR */
335 	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, p_mbr, 1);
336 	memset(p_mbr, 0, sizeof(*p_mbr));
337 
338 	if (p_mbr == NULL) {
339 		printf("%s: calloc failed!\n", __func__);
340 		return -1;
341 	}
342 	/* Append signature */
343 	p_mbr->signature = MSDOS_MBR_SIGNATURE;
344 	p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
345 	p_mbr->partition_record[0].start_sect = 1;
346 	p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba - 1;
347 
348 	/* Write MBR sector to the MMC device */
349 	if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
350 		printf("** Can't write to device %d **\n",
351 			dev_desc->dev);
352 		return -1;
353 	}
354 
355 	return 0;
356 }
357 
358 int write_gpt_table(block_dev_desc_t *dev_desc,
359 		gpt_header *gpt_h, gpt_entry *gpt_e)
360 {
361 	const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
362 					   * sizeof(gpt_entry)), dev_desc);
363 	u32 calc_crc32;
364 
365 	debug("max lba: %x\n", (u32) dev_desc->lba);
366 	/* Setup the Protective MBR */
367 	if (set_protective_mbr(dev_desc) < 0)
368 		goto err;
369 
370 	/* Generate CRC for the Primary GPT Header */
371 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
372 			      le32_to_cpu(gpt_h->num_partition_entries) *
373 			      le32_to_cpu(gpt_h->sizeof_partition_entry));
374 	gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
375 
376 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
377 			      le32_to_cpu(gpt_h->header_size));
378 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
379 
380 	/* Write the First GPT to the block right after the Legacy MBR */
381 	if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
382 		goto err;
383 
384 	if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_cnt, gpt_e)
385 	    != pte_blk_cnt)
386 		goto err;
387 
388 	prepare_backup_gpt_header(gpt_h);
389 
390 	if (dev_desc->block_write(dev_desc->dev,
391 				  (lbaint_t)le64_to_cpu(gpt_h->last_usable_lba)
392 				  + 1,
393 				  pte_blk_cnt, gpt_e) != pte_blk_cnt)
394 		goto err;
395 
396 	if (dev_desc->block_write(dev_desc->dev,
397 				  (lbaint_t)le64_to_cpu(gpt_h->my_lba), 1,
398 				  gpt_h) != 1)
399 		goto err;
400 
401 	debug("GPT successfully written to block device!\n");
402 	return 0;
403 
404  err:
405 	printf("** Can't write to device %d **\n", dev_desc->dev);
406 	return -1;
407 }
408 
409 int gpt_fill_pte(gpt_header *gpt_h, gpt_entry *gpt_e,
410 		disk_partition_t *partitions, int parts)
411 {
412 	lbaint_t offset = (lbaint_t)le64_to_cpu(gpt_h->first_usable_lba);
413 	lbaint_t start;
414 	lbaint_t last_usable_lba = (lbaint_t)
415 			le64_to_cpu(gpt_h->last_usable_lba);
416 	int i, k;
417 	size_t efiname_len, dosname_len;
418 #ifdef CONFIG_PARTITION_UUIDS
419 	char *str_uuid;
420 	unsigned char *bin_uuid;
421 #endif
422 
423 	for (i = 0; i < parts; i++) {
424 		/* partition starting lba */
425 		start = partitions[i].start;
426 		if (start && (start < offset)) {
427 			printf("Partition overlap\n");
428 			return -1;
429 		}
430 		if (start) {
431 			gpt_e[i].starting_lba = cpu_to_le64(start);
432 			offset = start + partitions[i].size;
433 		} else {
434 			gpt_e[i].starting_lba = cpu_to_le64(offset);
435 			offset += partitions[i].size;
436 		}
437 		if (offset >= last_usable_lba) {
438 			printf("Partitions layout exceds disk size\n");
439 			return -1;
440 		}
441 		/* partition ending lba */
442 		if ((i == parts - 1) && (partitions[i].size == 0))
443 			/* extend the last partition to maximuim */
444 			gpt_e[i].ending_lba = gpt_h->last_usable_lba;
445 		else
446 			gpt_e[i].ending_lba = cpu_to_le64(offset - 1);
447 
448 		/* partition type GUID */
449 		memcpy(gpt_e[i].partition_type_guid.b,
450 			&PARTITION_BASIC_DATA_GUID, 16);
451 
452 #ifdef CONFIG_PARTITION_UUIDS
453 		str_uuid = partitions[i].uuid;
454 		bin_uuid = gpt_e[i].unique_partition_guid.b;
455 
456 		if (uuid_str_to_bin(str_uuid, bin_uuid, UUID_STR_FORMAT_STD)) {
457 			printf("Partition no. %d: invalid guid: %s\n",
458 				i, str_uuid);
459 			return -1;
460 		}
461 #endif
462 
463 		/* partition attributes */
464 		memset(&gpt_e[i].attributes, 0,
465 		       sizeof(gpt_entry_attributes));
466 
467 		/* partition name */
468 		efiname_len = sizeof(gpt_e[i].partition_name)
469 			/ sizeof(efi_char16_t);
470 		dosname_len = sizeof(partitions[i].name);
471 
472 		memset(gpt_e[i].partition_name, 0,
473 		       sizeof(gpt_e[i].partition_name));
474 
475 		for (k = 0; k < min(dosname_len, efiname_len); k++)
476 			gpt_e[i].partition_name[k] =
477 				(efi_char16_t)(partitions[i].name[k]);
478 
479 		debug("%s: name: %s offset[%d]: 0x" LBAF
480 		      " size[%d]: 0x" LBAF "\n",
481 		      __func__, partitions[i].name, i,
482 		      offset, i, partitions[i].size);
483 	}
484 
485 	return 0;
486 }
487 
488 int gpt_fill_header(block_dev_desc_t *dev_desc, gpt_header *gpt_h,
489 		char *str_guid, int parts_count)
490 {
491 	gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
492 	gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
493 	gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
494 	gpt_h->my_lba = cpu_to_le64(1);
495 	gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
496 	gpt_h->first_usable_lba = cpu_to_le64(34);
497 	gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
498 	gpt_h->partition_entry_lba = cpu_to_le64(2);
499 	gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
500 	gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
501 	gpt_h->header_crc32 = 0;
502 	gpt_h->partition_entry_array_crc32 = 0;
503 
504 	if (uuid_str_to_bin(str_guid, gpt_h->disk_guid.b, UUID_STR_FORMAT_GUID))
505 		return -1;
506 
507 	return 0;
508 }
509 
510 int gpt_restore(block_dev_desc_t *dev_desc, char *str_disk_guid,
511 		disk_partition_t *partitions, int parts_count)
512 {
513 	int ret;
514 
515 	gpt_header *gpt_h = calloc(1, PAD_TO_BLOCKSIZE(sizeof(gpt_header),
516 						       dev_desc));
517 	gpt_entry *gpt_e;
518 
519 	if (gpt_h == NULL) {
520 		printf("%s: calloc failed!\n", __func__);
521 		return -1;
522 	}
523 
524 	gpt_e = calloc(1, PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS
525 					       * sizeof(gpt_entry),
526 					       dev_desc));
527 	if (gpt_e == NULL) {
528 		printf("%s: calloc failed!\n", __func__);
529 		free(gpt_h);
530 		return -1;
531 	}
532 
533 	/* Generate Primary GPT header (LBA1) */
534 	ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
535 	if (ret)
536 		goto err;
537 
538 	/* Generate partition entries */
539 	ret = gpt_fill_pte(gpt_h, gpt_e, partitions, parts_count);
540 	if (ret)
541 		goto err;
542 
543 	/* Write GPT partition table */
544 	ret = write_gpt_table(dev_desc, gpt_h, gpt_e);
545 
546 err:
547 	free(gpt_e);
548 	free(gpt_h);
549 	return ret;
550 }
551 
552 int is_valid_gpt_buf(block_dev_desc_t *dev_desc, void *buf)
553 {
554 	gpt_header *gpt_h;
555 	gpt_entry *gpt_e;
556 
557 	/* determine start of GPT Header in the buffer */
558 	gpt_h = buf + (GPT_PRIMARY_PARTITION_TABLE_LBA *
559 		       dev_desc->blksz);
560 	if (validate_gpt_header(gpt_h, GPT_PRIMARY_PARTITION_TABLE_LBA,
561 				dev_desc->lba))
562 		return -1;
563 
564 	/* determine start of GPT Entries in the buffer */
565 	gpt_e = buf + (le64_to_cpu(gpt_h->partition_entry_lba) *
566 		       dev_desc->blksz);
567 	if (validate_gpt_entries(gpt_h, gpt_e))
568 		return -1;
569 
570 	return 0;
571 }
572 
573 int write_mbr_and_gpt_partitions(block_dev_desc_t *dev_desc, void *buf)
574 {
575 	gpt_header *gpt_h;
576 	gpt_entry *gpt_e;
577 	int gpt_e_blk_cnt;
578 	lbaint_t lba;
579 	int cnt;
580 
581 	if (is_valid_gpt_buf(dev_desc, buf))
582 		return -1;
583 
584 	/* determine start of GPT Header in the buffer */
585 	gpt_h = buf + (GPT_PRIMARY_PARTITION_TABLE_LBA *
586 		       dev_desc->blksz);
587 
588 	/* determine start of GPT Entries in the buffer */
589 	gpt_e = buf + (le64_to_cpu(gpt_h->partition_entry_lba) *
590 		       dev_desc->blksz);
591 	gpt_e_blk_cnt = BLOCK_CNT((le32_to_cpu(gpt_h->num_partition_entries) *
592 				   le32_to_cpu(gpt_h->sizeof_partition_entry)),
593 				  dev_desc);
594 
595 	/* write MBR */
596 	lba = 0;	/* MBR is always at 0 */
597 	cnt = 1;	/* MBR (1 block) */
598 	if (dev_desc->block_write(dev_desc->dev, lba, cnt, buf) != cnt) {
599 		printf("%s: failed writing '%s' (%d blks at 0x" LBAF ")\n",
600 		       __func__, "MBR", cnt, lba);
601 		return 1;
602 	}
603 
604 	/* write Primary GPT */
605 	lba = GPT_PRIMARY_PARTITION_TABLE_LBA;
606 	cnt = 1;	/* GPT Header (1 block) */
607 	if (dev_desc->block_write(dev_desc->dev, lba, cnt, gpt_h) != cnt) {
608 		printf("%s: failed writing '%s' (%d blks at 0x" LBAF ")\n",
609 		       __func__, "Primary GPT Header", cnt, lba);
610 		return 1;
611 	}
612 
613 	lba = le64_to_cpu(gpt_h->partition_entry_lba);
614 	cnt = gpt_e_blk_cnt;
615 	if (dev_desc->block_write(dev_desc->dev, lba, cnt, gpt_e) != cnt) {
616 		printf("%s: failed writing '%s' (%d blks at 0x" LBAF ")\n",
617 		       __func__, "Primary GPT Entries", cnt, lba);
618 		return 1;
619 	}
620 
621 	prepare_backup_gpt_header(gpt_h);
622 
623 	/* write Backup GPT */
624 	lba = le64_to_cpu(gpt_h->partition_entry_lba);
625 	cnt = gpt_e_blk_cnt;
626 	if (dev_desc->block_write(dev_desc->dev, lba, cnt, gpt_e) != cnt) {
627 		printf("%s: failed writing '%s' (%d blks at 0x" LBAF ")\n",
628 		       __func__, "Backup GPT Entries", cnt, lba);
629 		return 1;
630 	}
631 
632 	lba = le64_to_cpu(gpt_h->my_lba);
633 	cnt = 1;	/* GPT Header (1 block) */
634 	if (dev_desc->block_write(dev_desc->dev, lba, cnt, gpt_h) != cnt) {
635 		printf("%s: failed writing '%s' (%d blks at 0x" LBAF ")\n",
636 		       __func__, "Backup GPT Header", cnt, lba);
637 		return 1;
638 	}
639 
640 	return 0;
641 }
642 #endif
643 
644 /*
645  * Private functions
646  */
647 /*
648  * pmbr_part_valid(): Check for EFI partition signature
649  *
650  * Returns: 1 if EFI GPT partition type is found.
651  */
652 static int pmbr_part_valid(struct partition *part)
653 {
654 	if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
655 		get_unaligned_le32(&part->start_sect) == 1UL) {
656 		return 1;
657 	}
658 
659 	return 0;
660 }
661 
662 /*
663  * is_pmbr_valid(): test Protective MBR for validity
664  *
665  * Returns: 1 if PMBR is valid, 0 otherwise.
666  * Validity depends on two things:
667  *  1) MSDOS signature is in the last two bytes of the MBR
668  *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
669  */
670 static int is_pmbr_valid(legacy_mbr * mbr)
671 {
672 	int i = 0;
673 
674 	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
675 		return 0;
676 
677 	for (i = 0; i < 4; i++) {
678 		if (pmbr_part_valid(&mbr->partition_record[i])) {
679 			return 1;
680 		}
681 	}
682 	return 0;
683 }
684 
685 /**
686  * is_gpt_valid() - tests one GPT header and PTEs for validity
687  *
688  * lba is the logical block address of the GPT header to test
689  * gpt is a GPT header ptr, filled on return.
690  * ptes is a PTEs ptr, filled on return.
691  *
692  * Description: returns 1 if valid,  0 on error.
693  * If valid, returns pointers to PTEs.
694  */
695 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
696 			gpt_header *pgpt_head, gpt_entry **pgpt_pte)
697 {
698 	if (!dev_desc || !pgpt_head) {
699 		printf("%s: Invalid Argument(s)\n", __func__);
700 		return 0;
701 	}
702 
703 	/* Read GPT Header from device */
704 	if (dev_desc->block_read(dev_desc->dev, (lbaint_t)lba, 1, pgpt_head)
705 			!= 1) {
706 		printf("*** ERROR: Can't read GPT header ***\n");
707 		return 0;
708 	}
709 
710 	if (validate_gpt_header(pgpt_head, (lbaint_t)lba, dev_desc->lba))
711 		return 0;
712 
713 	/* Read and allocate Partition Table Entries */
714 	*pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
715 	if (*pgpt_pte == NULL) {
716 		printf("GPT: Failed to allocate memory for PTE\n");
717 		return 0;
718 	}
719 
720 	if (validate_gpt_entries(pgpt_head, *pgpt_pte)) {
721 		free(*pgpt_pte);
722 		return 0;
723 	}
724 
725 	/* We're done, all's well */
726 	return 1;
727 }
728 
729 /**
730  * alloc_read_gpt_entries(): reads partition entries from disk
731  * @dev_desc
732  * @gpt - GPT header
733  *
734  * Description: Returns ptes on success,  NULL on error.
735  * Allocates space for PTEs based on information found in @gpt.
736  * Notes: remember to free pte when you're done!
737  */
738 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
739 					 gpt_header * pgpt_head)
740 {
741 	size_t count = 0, blk_cnt;
742 	gpt_entry *pte = NULL;
743 
744 	if (!dev_desc || !pgpt_head) {
745 		printf("%s: Invalid Argument(s)\n", __func__);
746 		return NULL;
747 	}
748 
749 	count = le32_to_cpu(pgpt_head->num_partition_entries) *
750 		le32_to_cpu(pgpt_head->sizeof_partition_entry);
751 
752 	debug("%s: count = %u * %u = %zu\n", __func__,
753 	      (u32) le32_to_cpu(pgpt_head->num_partition_entries),
754 	      (u32) le32_to_cpu(pgpt_head->sizeof_partition_entry), count);
755 
756 	/* Allocate memory for PTE, remember to FREE */
757 	if (count != 0) {
758 		pte = memalign(ARCH_DMA_MINALIGN,
759 			       PAD_TO_BLOCKSIZE(count, dev_desc));
760 	}
761 
762 	if (count == 0 || pte == NULL) {
763 		printf("%s: ERROR: Can't allocate 0x%zX "
764 		       "bytes for GPT Entries\n",
765 			__func__, count);
766 		return NULL;
767 	}
768 
769 	/* Read GPT Entries from device */
770 	blk_cnt = BLOCK_CNT(count, dev_desc);
771 	if (dev_desc->block_read (dev_desc->dev,
772 		(lbaint_t)le64_to_cpu(pgpt_head->partition_entry_lba),
773 		(lbaint_t) (blk_cnt), pte)
774 		!= blk_cnt) {
775 
776 		printf("*** ERROR: Can't read GPT Entries ***\n");
777 		free(pte);
778 		return NULL;
779 	}
780 	return pte;
781 }
782 
783 /**
784  * is_pte_valid(): validates a single Partition Table Entry
785  * @gpt_entry - Pointer to a single Partition Table Entry
786  *
787  * Description: returns 1 if valid,  0 on error.
788  */
789 static int is_pte_valid(gpt_entry * pte)
790 {
791 	efi_guid_t unused_guid;
792 
793 	if (!pte) {
794 		printf("%s: Invalid Argument(s)\n", __func__);
795 		return 0;
796 	}
797 
798 	/* Only one validation for now:
799 	 * The GUID Partition Type != Unused Entry (ALL-ZERO)
800 	 */
801 	memset(unused_guid.b, 0, sizeof(unused_guid.b));
802 
803 	if (memcmp(pte->partition_type_guid.b, unused_guid.b,
804 		sizeof(unused_guid.b)) == 0) {
805 
806 		debug("%s: Found an unused PTE GUID at 0x%08X\n", __func__,
807 		      (unsigned int)(uintptr_t)pte);
808 
809 		return 0;
810 	} else {
811 		return 1;
812 	}
813 }
814 #endif
815