xref: /rk3399_rockchip-uboot/disk/part_efi.c (revision e1f6b0a02d3bf45737fcb2addf4125cebe0cbcf9)
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 <part_efi.h>
20 #include <linux/ctype.h>
21 
22 DECLARE_GLOBAL_DATA_PTR;
23 
24 #ifdef HAVE_BLOCK_DEVICE
25 /**
26  * efi_crc32() - EFI version of crc32 function
27  * @buf: buffer to calculate crc32 of
28  * @len - length of buf
29  *
30  * Description: Returns EFI-style CRC32 value for @buf
31  */
32 static inline u32 efi_crc32(const void *buf, u32 len)
33 {
34 	return crc32(0, buf, len);
35 }
36 
37 /*
38  * Private function prototypes
39  */
40 
41 static int pmbr_part_valid(struct partition *part);
42 static int is_pmbr_valid(legacy_mbr * mbr);
43 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
44 				gpt_header *pgpt_head, gpt_entry **pgpt_pte);
45 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
46 				gpt_header * pgpt_head);
47 static int is_pte_valid(gpt_entry * pte);
48 
49 static char *print_efiname(gpt_entry *pte)
50 {
51 	static char name[PARTNAME_SZ + 1];
52 	int i;
53 	for (i = 0; i < PARTNAME_SZ; i++) {
54 		u8 c;
55 		c = pte->partition_name[i] & 0xff;
56 		c = (c && !isprint(c)) ? '.' : c;
57 		name[i] = c;
58 	}
59 	name[PARTNAME_SZ] = 0;
60 	return name;
61 }
62 
63 static efi_guid_t system_guid = PARTITION_SYSTEM_GUID;
64 
65 static inline int is_bootable(gpt_entry *p)
66 {
67 	return p->attributes.fields.legacy_bios_bootable ||
68 		!memcmp(&(p->partition_type_guid), &system_guid,
69 			sizeof(efi_guid_t));
70 }
71 
72 static int validate_gpt_header(gpt_header *gpt_h, lbaint_t lba,
73 		lbaint_t lastlba)
74 {
75 	uint32_t crc32_backup = 0;
76 	uint32_t calc_crc32;
77 
78 	/* Check the GPT header signature */
79 	if (le64_to_cpu(gpt_h->signature) != GPT_HEADER_SIGNATURE) {
80 		printf("%s signature is wrong: 0x%llX != 0x%llX\n",
81 		       "GUID Partition Table Header",
82 		       le64_to_cpu(gpt_h->signature),
83 		       GPT_HEADER_SIGNATURE);
84 		return -1;
85 	}
86 
87 	/* Check the GUID Partition Table CRC */
88 	memcpy(&crc32_backup, &gpt_h->header_crc32, sizeof(crc32_backup));
89 	memset(&gpt_h->header_crc32, 0, sizeof(gpt_h->header_crc32));
90 
91 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
92 		le32_to_cpu(gpt_h->header_size));
93 
94 	memcpy(&gpt_h->header_crc32, &crc32_backup, sizeof(crc32_backup));
95 
96 	if (calc_crc32 != le32_to_cpu(crc32_backup)) {
97 		printf("%s CRC is wrong: 0x%x != 0x%x\n",
98 		       "GUID Partition Table Header",
99 		       le32_to_cpu(crc32_backup), calc_crc32);
100 		return -1;
101 	}
102 
103 	/*
104 	 * Check that the my_lba entry points to the LBA that contains the GPT
105 	 */
106 	if (le64_to_cpu(gpt_h->my_lba) != lba) {
107 		printf("GPT: my_lba incorrect: %llX != " LBAF "\n",
108 		       le64_to_cpu(gpt_h->my_lba),
109 		       lba);
110 		return -1;
111 	}
112 
113 	/*
114 	 * Check that the first_usable_lba and that the last_usable_lba are
115 	 * within the disk.
116 	 */
117 	if (le64_to_cpu(gpt_h->first_usable_lba) > lastlba) {
118 		printf("GPT: first_usable_lba incorrect: %llX > " LBAF "\n",
119 		       le64_to_cpu(gpt_h->first_usable_lba), lastlba);
120 		return -1;
121 	}
122 	if (le64_to_cpu(gpt_h->last_usable_lba) > lastlba) {
123 		printf("GPT: last_usable_lba incorrect: %llX > " LBAF "\n",
124 		       le64_to_cpu(gpt_h->last_usable_lba), lastlba);
125 		return -1;
126 	}
127 
128 	debug("GPT: first_usable_lba: %llX last_usable_lba: %llX last lba: "
129 	      LBAF "\n", le64_to_cpu(gpt_h->first_usable_lba),
130 	      le64_to_cpu(gpt_h->last_usable_lba), lastlba);
131 
132 	return 0;
133 }
134 
135 static int validate_gpt_entries(gpt_header *gpt_h, gpt_entry *gpt_e)
136 {
137 	uint32_t calc_crc32;
138 
139 	/* Check the GUID Partition Table Entry Array CRC */
140 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
141 		le32_to_cpu(gpt_h->num_partition_entries) *
142 		le32_to_cpu(gpt_h->sizeof_partition_entry));
143 
144 	if (calc_crc32 != le32_to_cpu(gpt_h->partition_entry_array_crc32)) {
145 		printf("%s: 0x%x != 0x%x\n",
146 		       "GUID Partition Table Entry Array CRC is wrong",
147 		       le32_to_cpu(gpt_h->partition_entry_array_crc32),
148 		       calc_crc32);
149 		return -1;
150 	}
151 
152 	return 0;
153 }
154 
155 static void prepare_backup_gpt_header(gpt_header *gpt_h)
156 {
157 	uint32_t calc_crc32;
158 	uint64_t val;
159 
160 	/* recalculate the values for the Backup GPT Header */
161 	val = le64_to_cpu(gpt_h->my_lba);
162 	gpt_h->my_lba = gpt_h->alternate_lba;
163 	gpt_h->alternate_lba = cpu_to_le64(val);
164 	gpt_h->header_crc32 = 0;
165 
166 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
167 			       le32_to_cpu(gpt_h->header_size));
168 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
169 }
170 
171 #ifdef CONFIG_EFI_PARTITION
172 /*
173  * Public Functions (include/part.h)
174  */
175 
176 void print_part_efi(block_dev_desc_t * dev_desc)
177 {
178 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
179 	gpt_entry *gpt_pte = NULL;
180 	int i = 0;
181 	char uuid[37];
182 	unsigned char *uuid_bin;
183 
184 	if (!dev_desc) {
185 		printf("%s: Invalid Argument(s)\n", __func__);
186 		return;
187 	}
188 	/* This function validates AND fills in the GPT header and PTE */
189 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
190 			 gpt_head, &gpt_pte) != 1) {
191 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
192 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
193 				 gpt_head, &gpt_pte) != 1) {
194 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
195 			       __func__);
196 			return;
197 		} else {
198 			printf("%s: ***        Using Backup GPT ***\n",
199 			       __func__);
200 		}
201 	}
202 
203 	debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
204 
205 	printf("Part\tStart LBA\tEnd LBA\t\tName\n");
206 	printf("\tAttributes\n");
207 	printf("\tType GUID\n");
208 	printf("\tPartition GUID\n");
209 
210 	for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
211 		/* Stop at the first non valid PTE */
212 		if (!is_pte_valid(&gpt_pte[i]))
213 			break;
214 
215 		printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
216 			le64_to_cpu(gpt_pte[i].starting_lba),
217 			le64_to_cpu(gpt_pte[i].ending_lba),
218 			print_efiname(&gpt_pte[i]));
219 		printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
220 		uuid_bin = (unsigned char *)gpt_pte[i].partition_type_guid.b;
221 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
222 		printf("\ttype:\t%s\n", uuid);
223 		uuid_bin = (unsigned char *)gpt_pte[i].unique_partition_guid.b;
224 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
225 		printf("\tguid:\t%s\n", uuid);
226 	}
227 
228 	/* Remember to free pte */
229 	free(gpt_pte);
230 	return;
231 }
232 
233 int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
234 				disk_partition_t * info)
235 {
236 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
237 	gpt_entry *gpt_pte = NULL;
238 
239 	/* "part" argument must be at least 1 */
240 	if (!dev_desc || !info || part < 1) {
241 		printf("%s: Invalid Argument(s)\n", __func__);
242 		return -1;
243 	}
244 
245 	/* This function validates AND fills in the GPT header and PTE */
246 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
247 			gpt_head, &gpt_pte) != 1) {
248 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
249 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
250 				 gpt_head, &gpt_pte) != 1) {
251 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
252 			       __func__);
253 			return -1;
254 		} else {
255 			printf("%s: ***        Using Backup GPT ***\n",
256 			       __func__);
257 		}
258 	}
259 
260 	if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
261 	    !is_pte_valid(&gpt_pte[part - 1])) {
262 		debug("%s: *** ERROR: Invalid partition number %d ***\n",
263 			__func__, part);
264 		free(gpt_pte);
265 		return -1;
266 	}
267 
268 	/* The 'lbaint_t' casting may limit the maximum disk size to 2 TB */
269 	info->start = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].starting_lba);
270 	/* The ending LBA is inclusive, to calculate size, add 1 to it */
271 	info->size = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1
272 		     - info->start;
273 	info->blksz = dev_desc->blksz;
274 
275 	sprintf((char *)info->name, "%s",
276 			print_efiname(&gpt_pte[part - 1]));
277 	sprintf((char *)info->type, "U-Boot");
278 	info->bootable = is_bootable(&gpt_pte[part - 1]);
279 #ifdef CONFIG_PARTITION_UUIDS
280 	uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid,
281 			UUID_STR_FORMAT_GUID);
282 #endif
283 
284 	debug("%s: start 0x" LBAF ", size 0x" LBAF ", name %s\n", __func__,
285 	      info->start, info->size, info->name);
286 
287 	/* Remember to free pte */
288 	free(gpt_pte);
289 	return 0;
290 }
291 
292 int get_partition_info_efi_by_name(block_dev_desc_t *dev_desc,
293 	const char *name, disk_partition_t *info)
294 {
295 	int ret;
296 	int i;
297 	for (i = 1; i < GPT_ENTRY_NUMBERS; i++) {
298 		ret = get_partition_info_efi(dev_desc, i, info);
299 		if (ret != 0) {
300 			/* no more entries in table */
301 			return -1;
302 		}
303 		if (strcmp(name, (const char *)info->name) == 0) {
304 			/* matched */
305 			return 0;
306 		}
307 	}
308 	return -2;
309 }
310 
311 int test_part_efi(block_dev_desc_t * dev_desc)
312 {
313 	ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);
314 
315 	/* Read legacy MBR from block 0 and validate it */
316 	if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)legacymbr) != 1)
317 		|| (is_pmbr_valid(legacymbr) != 1)) {
318 		return -1;
319 	}
320 	return 0;
321 }
322 
323 /**
324  * set_protective_mbr(): Set the EFI protective MBR
325  * @param dev_desc - block device descriptor
326  *
327  * @return - zero on success, otherwise error
328  */
329 static int set_protective_mbr(block_dev_desc_t *dev_desc)
330 {
331 	/* Setup the Protective MBR */
332 	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, p_mbr, 1);
333 	memset(p_mbr, 0, sizeof(*p_mbr));
334 
335 	if (p_mbr == NULL) {
336 		printf("%s: calloc failed!\n", __func__);
337 		return -1;
338 	}
339 	/* Append signature */
340 	p_mbr->signature = MSDOS_MBR_SIGNATURE;
341 	p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
342 	p_mbr->partition_record[0].start_sect = 1;
343 	p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
344 
345 	/* Write MBR sector to the MMC device */
346 	if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
347 		printf("** Can't write to device %d **\n",
348 			dev_desc->dev);
349 		return -1;
350 	}
351 
352 	return 0;
353 }
354 
355 int write_gpt_table(block_dev_desc_t *dev_desc,
356 		gpt_header *gpt_h, gpt_entry *gpt_e)
357 {
358 	const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
359 					   * sizeof(gpt_entry)), dev_desc);
360 	u32 calc_crc32;
361 
362 	debug("max lba: %x\n", (u32) dev_desc->lba);
363 	/* Setup the Protective MBR */
364 	if (set_protective_mbr(dev_desc) < 0)
365 		goto err;
366 
367 	/* Generate CRC for the Primary GPT Header */
368 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
369 			      le32_to_cpu(gpt_h->num_partition_entries) *
370 			      le32_to_cpu(gpt_h->sizeof_partition_entry));
371 	gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
372 
373 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
374 			      le32_to_cpu(gpt_h->header_size));
375 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
376 
377 	/* Write the First GPT to the block right after the Legacy MBR */
378 	if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
379 		goto err;
380 
381 	if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_cnt, gpt_e)
382 	    != pte_blk_cnt)
383 		goto err;
384 
385 	prepare_backup_gpt_header(gpt_h);
386 
387 	if (dev_desc->block_write(dev_desc->dev,
388 				  (lbaint_t)le64_to_cpu(gpt_h->last_usable_lba)
389 				  + 1,
390 				  pte_blk_cnt, gpt_e) != pte_blk_cnt)
391 		goto err;
392 
393 	if (dev_desc->block_write(dev_desc->dev,
394 				  (lbaint_t)le64_to_cpu(gpt_h->my_lba), 1,
395 				  gpt_h) != 1)
396 		goto err;
397 
398 	debug("GPT successfully written to block device!\n");
399 	return 0;
400 
401  err:
402 	printf("** Can't write to device %d **\n", dev_desc->dev);
403 	return -1;
404 }
405 
406 int gpt_fill_pte(gpt_header *gpt_h, gpt_entry *gpt_e,
407 		disk_partition_t *partitions, int parts)
408 {
409 	lbaint_t offset = (lbaint_t)le64_to_cpu(gpt_h->first_usable_lba);
410 	lbaint_t start;
411 	lbaint_t last_usable_lba = (lbaint_t)
412 			le64_to_cpu(gpt_h->last_usable_lba);
413 	int i, k;
414 	size_t efiname_len, dosname_len;
415 #ifdef CONFIG_PARTITION_UUIDS
416 	char *str_uuid;
417 	unsigned char *bin_uuid;
418 #endif
419 
420 	for (i = 0; i < parts; i++) {
421 		/* partition starting lba */
422 		start = partitions[i].start;
423 		if (start && (start < offset)) {
424 			printf("Partition overlap\n");
425 			return -1;
426 		}
427 		if (start) {
428 			gpt_e[i].starting_lba = cpu_to_le64(start);
429 			offset = start + partitions[i].size;
430 		} else {
431 			gpt_e[i].starting_lba = cpu_to_le64(offset);
432 			offset += partitions[i].size;
433 		}
434 		if (offset >= last_usable_lba) {
435 			printf("Partitions layout exceds disk size\n");
436 			return -1;
437 		}
438 		/* partition ending lba */
439 		if ((i == parts - 1) && (partitions[i].size == 0))
440 			/* extend the last partition to maximuim */
441 			gpt_e[i].ending_lba = gpt_h->last_usable_lba;
442 		else
443 			gpt_e[i].ending_lba = cpu_to_le64(offset - 1);
444 
445 		/* partition type GUID */
446 		memcpy(gpt_e[i].partition_type_guid.b,
447 			&PARTITION_BASIC_DATA_GUID, 16);
448 
449 #ifdef CONFIG_PARTITION_UUIDS
450 		str_uuid = partitions[i].uuid;
451 		bin_uuid = gpt_e[i].unique_partition_guid.b;
452 
453 		if (uuid_str_to_bin(str_uuid, bin_uuid, UUID_STR_FORMAT_STD)) {
454 			printf("Partition no. %d: invalid guid: %s\n",
455 				i, str_uuid);
456 			return -1;
457 		}
458 #endif
459 
460 		/* partition attributes */
461 		memset(&gpt_e[i].attributes, 0,
462 		       sizeof(gpt_entry_attributes));
463 
464 		/* partition name */
465 		efiname_len = sizeof(gpt_e[i].partition_name)
466 			/ sizeof(efi_char16_t);
467 		dosname_len = sizeof(partitions[i].name);
468 
469 		memset(gpt_e[i].partition_name, 0,
470 		       sizeof(gpt_e[i].partition_name));
471 
472 		for (k = 0; k < min(dosname_len, efiname_len); k++)
473 			gpt_e[i].partition_name[k] =
474 				(efi_char16_t)(partitions[i].name[k]);
475 
476 		debug("%s: name: %s offset[%d]: 0x" LBAF
477 		      " size[%d]: 0x" LBAF "\n",
478 		      __func__, partitions[i].name, i,
479 		      offset, i, partitions[i].size);
480 	}
481 
482 	return 0;
483 }
484 
485 int gpt_fill_header(block_dev_desc_t *dev_desc, gpt_header *gpt_h,
486 		char *str_guid, int parts_count)
487 {
488 	gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
489 	gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
490 	gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
491 	gpt_h->my_lba = cpu_to_le64(1);
492 	gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
493 	gpt_h->first_usable_lba = cpu_to_le64(34);
494 	gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
495 	gpt_h->partition_entry_lba = cpu_to_le64(2);
496 	gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
497 	gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
498 	gpt_h->header_crc32 = 0;
499 	gpt_h->partition_entry_array_crc32 = 0;
500 
501 	if (uuid_str_to_bin(str_guid, gpt_h->disk_guid.b, UUID_STR_FORMAT_GUID))
502 		return -1;
503 
504 	return 0;
505 }
506 
507 int gpt_restore(block_dev_desc_t *dev_desc, char *str_disk_guid,
508 		disk_partition_t *partitions, int parts_count)
509 {
510 	int ret;
511 
512 	gpt_header *gpt_h = calloc(1, PAD_TO_BLOCKSIZE(sizeof(gpt_header),
513 						       dev_desc));
514 	gpt_entry *gpt_e;
515 
516 	if (gpt_h == NULL) {
517 		printf("%s: calloc failed!\n", __func__);
518 		return -1;
519 	}
520 
521 	gpt_e = calloc(1, PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS
522 					       * sizeof(gpt_entry),
523 					       dev_desc));
524 	if (gpt_e == NULL) {
525 		printf("%s: calloc failed!\n", __func__);
526 		free(gpt_h);
527 		return -1;
528 	}
529 
530 	/* Generate Primary GPT header (LBA1) */
531 	ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
532 	if (ret)
533 		goto err;
534 
535 	/* Generate partition entries */
536 	ret = gpt_fill_pte(gpt_h, gpt_e, partitions, parts_count);
537 	if (ret)
538 		goto err;
539 
540 	/* Write GPT partition table */
541 	ret = write_gpt_table(dev_desc, gpt_h, gpt_e);
542 
543 err:
544 	free(gpt_e);
545 	free(gpt_h);
546 	return ret;
547 }
548 #endif
549 
550 /*
551  * Private functions
552  */
553 /*
554  * pmbr_part_valid(): Check for EFI partition signature
555  *
556  * Returns: 1 if EFI GPT partition type is found.
557  */
558 static int pmbr_part_valid(struct partition *part)
559 {
560 	if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
561 		get_unaligned_le32(&part->start_sect) == 1UL) {
562 		return 1;
563 	}
564 
565 	return 0;
566 }
567 
568 /*
569  * is_pmbr_valid(): test Protective MBR for validity
570  *
571  * Returns: 1 if PMBR is valid, 0 otherwise.
572  * Validity depends on two things:
573  *  1) MSDOS signature is in the last two bytes of the MBR
574  *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
575  */
576 static int is_pmbr_valid(legacy_mbr * mbr)
577 {
578 	int i = 0;
579 
580 	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
581 		return 0;
582 
583 	for (i = 0; i < 4; i++) {
584 		if (pmbr_part_valid(&mbr->partition_record[i])) {
585 			return 1;
586 		}
587 	}
588 	return 0;
589 }
590 
591 /**
592  * is_gpt_valid() - tests one GPT header and PTEs for validity
593  *
594  * lba is the logical block address of the GPT header to test
595  * gpt is a GPT header ptr, filled on return.
596  * ptes is a PTEs ptr, filled on return.
597  *
598  * Description: returns 1 if valid,  0 on error.
599  * If valid, returns pointers to PTEs.
600  */
601 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
602 			gpt_header *pgpt_head, gpt_entry **pgpt_pte)
603 {
604 	if (!dev_desc || !pgpt_head) {
605 		printf("%s: Invalid Argument(s)\n", __func__);
606 		return 0;
607 	}
608 
609 	/* Read GPT Header from device */
610 	if (dev_desc->block_read(dev_desc->dev, (lbaint_t)lba, 1, pgpt_head)
611 			!= 1) {
612 		printf("*** ERROR: Can't read GPT header ***\n");
613 		return 0;
614 	}
615 
616 	if (validate_gpt_header(pgpt_head, (lbaint_t)lba, dev_desc->lba))
617 		return 0;
618 
619 	/* Read and allocate Partition Table Entries */
620 	*pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
621 	if (*pgpt_pte == NULL) {
622 		printf("GPT: Failed to allocate memory for PTE\n");
623 		return 0;
624 	}
625 
626 	if (validate_gpt_entries(pgpt_head, *pgpt_pte)) {
627 		free(*pgpt_pte);
628 		return 0;
629 	}
630 
631 	/* We're done, all's well */
632 	return 1;
633 }
634 
635 /**
636  * alloc_read_gpt_entries(): reads partition entries from disk
637  * @dev_desc
638  * @gpt - GPT header
639  *
640  * Description: Returns ptes on success,  NULL on error.
641  * Allocates space for PTEs based on information found in @gpt.
642  * Notes: remember to free pte when you're done!
643  */
644 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
645 					 gpt_header * pgpt_head)
646 {
647 	size_t count = 0, blk_cnt;
648 	gpt_entry *pte = NULL;
649 
650 	if (!dev_desc || !pgpt_head) {
651 		printf("%s: Invalid Argument(s)\n", __func__);
652 		return NULL;
653 	}
654 
655 	count = le32_to_cpu(pgpt_head->num_partition_entries) *
656 		le32_to_cpu(pgpt_head->sizeof_partition_entry);
657 
658 	debug("%s: count = %u * %u = %zu\n", __func__,
659 	      (u32) le32_to_cpu(pgpt_head->num_partition_entries),
660 	      (u32) le32_to_cpu(pgpt_head->sizeof_partition_entry), count);
661 
662 	/* Allocate memory for PTE, remember to FREE */
663 	if (count != 0) {
664 		pte = memalign(ARCH_DMA_MINALIGN,
665 			       PAD_TO_BLOCKSIZE(count, dev_desc));
666 	}
667 
668 	if (count == 0 || pte == NULL) {
669 		printf("%s: ERROR: Can't allocate 0x%zX "
670 		       "bytes for GPT Entries\n",
671 			__func__, count);
672 		return NULL;
673 	}
674 
675 	/* Read GPT Entries from device */
676 	blk_cnt = BLOCK_CNT(count, dev_desc);
677 	if (dev_desc->block_read (dev_desc->dev,
678 		(lbaint_t)le64_to_cpu(pgpt_head->partition_entry_lba),
679 		(lbaint_t) (blk_cnt), pte)
680 		!= blk_cnt) {
681 
682 		printf("*** ERROR: Can't read GPT Entries ***\n");
683 		free(pte);
684 		return NULL;
685 	}
686 	return pte;
687 }
688 
689 /**
690  * is_pte_valid(): validates a single Partition Table Entry
691  * @gpt_entry - Pointer to a single Partition Table Entry
692  *
693  * Description: returns 1 if valid,  0 on error.
694  */
695 static int is_pte_valid(gpt_entry * pte)
696 {
697 	efi_guid_t unused_guid;
698 
699 	if (!pte) {
700 		printf("%s: Invalid Argument(s)\n", __func__);
701 		return 0;
702 	}
703 
704 	/* Only one validation for now:
705 	 * The GUID Partition Type != Unused Entry (ALL-ZERO)
706 	 */
707 	memset(unused_guid.b, 0, sizeof(unused_guid.b));
708 
709 	if (memcmp(pte->partition_type_guid.b, unused_guid.b,
710 		sizeof(unused_guid.b)) == 0) {
711 
712 		debug("%s: Found an unused PTE GUID at 0x%08X\n", __func__,
713 		      (unsigned int)(uintptr_t)pte);
714 
715 		return 0;
716 	} else {
717 		return 1;
718 	}
719 }
720 #endif
721