xref: /rk3399_rockchip-uboot/disk/part_efi.c (revision e04350d2991ed628587e94b5b6d89c24f439e172)
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 <malloc.h>
18 #include <part_efi.h>
19 #include <linux/ctype.h>
20 
21 DECLARE_GLOBAL_DATA_PTR;
22 
23 #ifdef HAVE_BLOCK_DEVICE
24 /**
25  * efi_crc32() - EFI version of crc32 function
26  * @buf: buffer to calculate crc32 of
27  * @len - length of buf
28  *
29  * Description: Returns EFI-style CRC32 value for @buf
30  */
31 static inline u32 efi_crc32(const void *buf, u32 len)
32 {
33 	return crc32(0, buf, len);
34 }
35 
36 /*
37  * Private function prototypes
38  */
39 
40 static int pmbr_part_valid(struct partition *part);
41 static int is_pmbr_valid(legacy_mbr * mbr);
42 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
43 				gpt_header *pgpt_head, gpt_entry **pgpt_pte);
44 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
45 				gpt_header * pgpt_head);
46 static int is_pte_valid(gpt_entry * pte);
47 
48 static char *print_efiname(gpt_entry *pte)
49 {
50 	static char name[PARTNAME_SZ + 1];
51 	int i;
52 	for (i = 0; i < PARTNAME_SZ; i++) {
53 		u8 c;
54 		c = pte->partition_name[i] & 0xff;
55 		c = (c && !isprint(c)) ? '.' : c;
56 		name[i] = c;
57 	}
58 	name[PARTNAME_SZ] = 0;
59 	return name;
60 }
61 
62 static efi_guid_t system_guid = PARTITION_SYSTEM_GUID;
63 
64 static inline int is_bootable(gpt_entry *p)
65 {
66 	return p->attributes.fields.legacy_bios_bootable ||
67 		!memcmp(&(p->partition_type_guid), &system_guid,
68 			sizeof(efi_guid_t));
69 }
70 
71 #ifdef CONFIG_EFI_PARTITION
72 /*
73  * Public Functions (include/part.h)
74  */
75 
76 void print_part_efi(block_dev_desc_t * dev_desc)
77 {
78 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
79 	gpt_entry *gpt_pte = NULL;
80 	int i = 0;
81 	char uuid[37];
82 	unsigned char *uuid_bin;
83 
84 	if (!dev_desc) {
85 		printf("%s: Invalid Argument(s)\n", __func__);
86 		return;
87 	}
88 	/* This function validates AND fills in the GPT header and PTE */
89 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
90 			 gpt_head, &gpt_pte) != 1) {
91 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
92 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
93 				 gpt_head, &gpt_pte) != 1) {
94 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
95 			       __func__);
96 			return;
97 		} else {
98 			printf("%s: ***        Using Backup GPT ***\n",
99 			       __func__);
100 		}
101 	}
102 
103 	debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
104 
105 	printf("Part\tStart LBA\tEnd LBA\t\tName\n");
106 	printf("\tAttributes\n");
107 	printf("\tType GUID\n");
108 	printf("\tPartition GUID\n");
109 
110 	for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
111 		/* Stop at the first non valid PTE */
112 		if (!is_pte_valid(&gpt_pte[i]))
113 			break;
114 
115 		printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
116 			le64_to_cpu(gpt_pte[i].starting_lba),
117 			le64_to_cpu(gpt_pte[i].ending_lba),
118 			print_efiname(&gpt_pte[i]));
119 		printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
120 		uuid_bin = (unsigned char *)gpt_pte[i].partition_type_guid.b;
121 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
122 		printf("\ttype:\t%s\n", uuid);
123 		uuid_bin = (unsigned char *)gpt_pte[i].unique_partition_guid.b;
124 		uuid_bin_to_str(uuid_bin, uuid, UUID_STR_FORMAT_GUID);
125 		printf("\tguid:\t%s\n", uuid);
126 	}
127 
128 	/* Remember to free pte */
129 	free(gpt_pte);
130 	return;
131 }
132 
133 int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
134 				disk_partition_t * info)
135 {
136 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
137 	gpt_entry *gpt_pte = NULL;
138 
139 	/* "part" argument must be at least 1 */
140 	if (!dev_desc || !info || part < 1) {
141 		printf("%s: Invalid Argument(s)\n", __func__);
142 		return -1;
143 	}
144 
145 	/* This function validates AND fills in the GPT header and PTE */
146 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
147 			gpt_head, &gpt_pte) != 1) {
148 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
149 		if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
150 				 gpt_head, &gpt_pte) != 1) {
151 			printf("%s: *** ERROR: Invalid Backup GPT ***\n",
152 			       __func__);
153 			return -1;
154 		} else {
155 			printf("%s: ***        Using Backup GPT ***\n",
156 			       __func__);
157 		}
158 	}
159 
160 	if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
161 	    !is_pte_valid(&gpt_pte[part - 1])) {
162 		debug("%s: *** ERROR: Invalid partition number %d ***\n",
163 			__func__, part);
164 		free(gpt_pte);
165 		return -1;
166 	}
167 
168 	/* The 'lbaint_t' casting may limit the maximum disk size to 2 TB */
169 	info->start = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].starting_lba);
170 	/* The ending LBA is inclusive, to calculate size, add 1 to it */
171 	info->size = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1
172 		     - info->start;
173 	info->blksz = dev_desc->blksz;
174 
175 	sprintf((char *)info->name, "%s",
176 			print_efiname(&gpt_pte[part - 1]));
177 	sprintf((char *)info->type, "U-Boot");
178 	info->bootable = is_bootable(&gpt_pte[part - 1]);
179 #ifdef CONFIG_PARTITION_UUIDS
180 	uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid,
181 			UUID_STR_FORMAT_GUID);
182 #endif
183 
184 	debug("%s: start 0x" LBAF ", size 0x" LBAF ", name %s", __func__,
185 	      info->start, info->size, info->name);
186 
187 	/* Remember to free pte */
188 	free(gpt_pte);
189 	return 0;
190 }
191 
192 int test_part_efi(block_dev_desc_t * dev_desc)
193 {
194 	ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);
195 
196 	/* Read legacy MBR from block 0 and validate it */
197 	if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)legacymbr) != 1)
198 		|| (is_pmbr_valid(legacymbr) != 1)) {
199 		return -1;
200 	}
201 	return 0;
202 }
203 
204 /**
205  * set_protective_mbr(): Set the EFI protective MBR
206  * @param dev_desc - block device descriptor
207  *
208  * @return - zero on success, otherwise error
209  */
210 static int set_protective_mbr(block_dev_desc_t *dev_desc)
211 {
212 	/* Setup the Protective MBR */
213 	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, p_mbr, 1);
214 	memset(p_mbr, 0, sizeof(*p_mbr));
215 
216 	if (p_mbr == NULL) {
217 		printf("%s: calloc failed!\n", __func__);
218 		return -1;
219 	}
220 	/* Append signature */
221 	p_mbr->signature = MSDOS_MBR_SIGNATURE;
222 	p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
223 	p_mbr->partition_record[0].start_sect = 1;
224 	p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
225 
226 	/* Write MBR sector to the MMC device */
227 	if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
228 		printf("** Can't write to device %d **\n",
229 			dev_desc->dev);
230 		return -1;
231 	}
232 
233 	return 0;
234 }
235 
236 int write_gpt_table(block_dev_desc_t *dev_desc,
237 		gpt_header *gpt_h, gpt_entry *gpt_e)
238 {
239 	const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
240 					   * sizeof(gpt_entry)), dev_desc);
241 	u32 calc_crc32;
242 	u64 val;
243 
244 	debug("max lba: %x\n", (u32) dev_desc->lba);
245 	/* Setup the Protective MBR */
246 	if (set_protective_mbr(dev_desc) < 0)
247 		goto err;
248 
249 	/* Generate CRC for the Primary GPT Header */
250 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
251 			      le32_to_cpu(gpt_h->num_partition_entries) *
252 			      le32_to_cpu(gpt_h->sizeof_partition_entry));
253 	gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
254 
255 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
256 			      le32_to_cpu(gpt_h->header_size));
257 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
258 
259 	/* Write the First GPT to the block right after the Legacy MBR */
260 	if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
261 		goto err;
262 
263 	if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_cnt, gpt_e)
264 	    != pte_blk_cnt)
265 		goto err;
266 
267 	/* recalculate the values for the Backup GPT Header */
268 	val = le64_to_cpu(gpt_h->my_lba);
269 	gpt_h->my_lba = gpt_h->alternate_lba;
270 	gpt_h->alternate_lba = cpu_to_le64(val);
271 	gpt_h->header_crc32 = 0;
272 
273 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
274 			      le32_to_cpu(gpt_h->header_size));
275 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
276 
277 	if (dev_desc->block_write(dev_desc->dev,
278 				  (lbaint_t)le64_to_cpu(gpt_h->last_usable_lba)
279 				  + 1,
280 				  pte_blk_cnt, gpt_e) != pte_blk_cnt)
281 		goto err;
282 
283 	if (dev_desc->block_write(dev_desc->dev,
284 				  (lbaint_t)le64_to_cpu(gpt_h->my_lba), 1,
285 				  gpt_h) != 1)
286 		goto err;
287 
288 	debug("GPT successfully written to block device!\n");
289 	return 0;
290 
291  err:
292 	printf("** Can't write to device %d **\n", dev_desc->dev);
293 	return -1;
294 }
295 
296 int gpt_fill_pte(gpt_header *gpt_h, gpt_entry *gpt_e,
297 		disk_partition_t *partitions, int parts)
298 {
299 	lbaint_t offset = (lbaint_t)le64_to_cpu(gpt_h->first_usable_lba);
300 	lbaint_t start;
301 	lbaint_t last_usable_lba = (lbaint_t)
302 			le64_to_cpu(gpt_h->last_usable_lba);
303 	int i, k;
304 	size_t efiname_len, dosname_len;
305 #ifdef CONFIG_PARTITION_UUIDS
306 	char *str_uuid;
307 	unsigned char *bin_uuid;
308 #endif
309 
310 	for (i = 0; i < parts; i++) {
311 		/* partition starting lba */
312 		start = partitions[i].start;
313 		if (start && (start < offset)) {
314 			printf("Partition overlap\n");
315 			return -1;
316 		}
317 		if (start) {
318 			gpt_e[i].starting_lba = cpu_to_le64(start);
319 			offset = start + partitions[i].size;
320 		} else {
321 			gpt_e[i].starting_lba = cpu_to_le64(offset);
322 			offset += partitions[i].size;
323 		}
324 		if (offset >= last_usable_lba) {
325 			printf("Partitions layout exceds disk size\n");
326 			return -1;
327 		}
328 		/* partition ending lba */
329 		if ((i == parts - 1) && (partitions[i].size == 0))
330 			/* extend the last partition to maximuim */
331 			gpt_e[i].ending_lba = gpt_h->last_usable_lba;
332 		else
333 			gpt_e[i].ending_lba = cpu_to_le64(offset - 1);
334 
335 		/* partition type GUID */
336 		memcpy(gpt_e[i].partition_type_guid.b,
337 			&PARTITION_BASIC_DATA_GUID, 16);
338 
339 #ifdef CONFIG_PARTITION_UUIDS
340 		str_uuid = partitions[i].uuid;
341 		bin_uuid = gpt_e[i].unique_partition_guid.b;
342 
343 		if (uuid_str_to_bin(str_uuid, bin_uuid, UUID_STR_FORMAT_STD)) {
344 			printf("Partition no. %d: invalid guid: %s\n",
345 				i, str_uuid);
346 			return -1;
347 		}
348 #endif
349 
350 		/* partition attributes */
351 		memset(&gpt_e[i].attributes, 0,
352 		       sizeof(gpt_entry_attributes));
353 
354 		/* partition name */
355 		efiname_len = sizeof(gpt_e[i].partition_name)
356 			/ sizeof(efi_char16_t);
357 		dosname_len = sizeof(partitions[i].name);
358 
359 		memset(gpt_e[i].partition_name, 0,
360 		       sizeof(gpt_e[i].partition_name));
361 
362 		for (k = 0; k < min(dosname_len, efiname_len); k++)
363 			gpt_e[i].partition_name[k] =
364 				(efi_char16_t)(partitions[i].name[k]);
365 
366 		debug("%s: name: %s offset[%d]: 0x" LBAF
367 		      " size[%d]: 0x" LBAF "\n",
368 		      __func__, partitions[i].name, i,
369 		      offset, i, partitions[i].size);
370 	}
371 
372 	return 0;
373 }
374 
375 int gpt_fill_header(block_dev_desc_t *dev_desc, gpt_header *gpt_h,
376 		char *str_guid, int parts_count)
377 {
378 	gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
379 	gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
380 	gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
381 	gpt_h->my_lba = cpu_to_le64(1);
382 	gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
383 	gpt_h->first_usable_lba = cpu_to_le64(34);
384 	gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
385 	gpt_h->partition_entry_lba = cpu_to_le64(2);
386 	gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
387 	gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
388 	gpt_h->header_crc32 = 0;
389 	gpt_h->partition_entry_array_crc32 = 0;
390 
391 	if (uuid_str_to_bin(str_guid, gpt_h->disk_guid.b, UUID_STR_FORMAT_GUID))
392 		return -1;
393 
394 	return 0;
395 }
396 
397 int gpt_restore(block_dev_desc_t *dev_desc, char *str_disk_guid,
398 		disk_partition_t *partitions, int parts_count)
399 {
400 	int ret;
401 
402 	gpt_header *gpt_h = calloc(1, PAD_TO_BLOCKSIZE(sizeof(gpt_header),
403 						       dev_desc));
404 	gpt_entry *gpt_e;
405 
406 	if (gpt_h == NULL) {
407 		printf("%s: calloc failed!\n", __func__);
408 		return -1;
409 	}
410 
411 	gpt_e = calloc(1, PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS
412 					       * sizeof(gpt_entry),
413 					       dev_desc));
414 	if (gpt_e == NULL) {
415 		printf("%s: calloc failed!\n", __func__);
416 		free(gpt_h);
417 		return -1;
418 	}
419 
420 	/* Generate Primary GPT header (LBA1) */
421 	ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
422 	if (ret)
423 		goto err;
424 
425 	/* Generate partition entries */
426 	ret = gpt_fill_pte(gpt_h, gpt_e, partitions, parts_count);
427 	if (ret)
428 		goto err;
429 
430 	/* Write GPT partition table */
431 	ret = write_gpt_table(dev_desc, gpt_h, gpt_e);
432 
433 err:
434 	free(gpt_e);
435 	free(gpt_h);
436 	return ret;
437 }
438 #endif
439 
440 /*
441  * Private functions
442  */
443 /*
444  * pmbr_part_valid(): Check for EFI partition signature
445  *
446  * Returns: 1 if EFI GPT partition type is found.
447  */
448 static int pmbr_part_valid(struct partition *part)
449 {
450 	if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
451 		get_unaligned_le32(&part->start_sect) == 1UL) {
452 		return 1;
453 	}
454 
455 	return 0;
456 }
457 
458 /*
459  * is_pmbr_valid(): test Protective MBR for validity
460  *
461  * Returns: 1 if PMBR is valid, 0 otherwise.
462  * Validity depends on two things:
463  *  1) MSDOS signature is in the last two bytes of the MBR
464  *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
465  */
466 static int is_pmbr_valid(legacy_mbr * mbr)
467 {
468 	int i = 0;
469 
470 	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
471 		return 0;
472 
473 	for (i = 0; i < 4; i++) {
474 		if (pmbr_part_valid(&mbr->partition_record[i])) {
475 			return 1;
476 		}
477 	}
478 	return 0;
479 }
480 
481 /**
482  * is_gpt_valid() - tests one GPT header and PTEs for validity
483  *
484  * lba is the logical block address of the GPT header to test
485  * gpt is a GPT header ptr, filled on return.
486  * ptes is a PTEs ptr, filled on return.
487  *
488  * Description: returns 1 if valid,  0 on error.
489  * If valid, returns pointers to PTEs.
490  */
491 static int is_gpt_valid(block_dev_desc_t *dev_desc, u64 lba,
492 			gpt_header *pgpt_head, gpt_entry **pgpt_pte)
493 {
494 	u32 crc32_backup = 0;
495 	u32 calc_crc32;
496 	u64 lastlba;
497 
498 	if (!dev_desc || !pgpt_head) {
499 		printf("%s: Invalid Argument(s)\n", __func__);
500 		return 0;
501 	}
502 
503 	/* Read GPT Header from device */
504 	if (dev_desc->block_read(dev_desc->dev, (lbaint_t)lba, 1, pgpt_head)
505 			!= 1) {
506 		printf("*** ERROR: Can't read GPT header ***\n");
507 		return 0;
508 	}
509 
510 	/* Check the GPT header signature */
511 	if (le64_to_cpu(pgpt_head->signature) != GPT_HEADER_SIGNATURE) {
512 		printf("GUID Partition Table Header signature is wrong:"
513 			"0x%llX != 0x%llX\n",
514 			le64_to_cpu(pgpt_head->signature),
515 			GPT_HEADER_SIGNATURE);
516 		return 0;
517 	}
518 
519 	/* Check the GUID Partition Table CRC */
520 	memcpy(&crc32_backup, &pgpt_head->header_crc32, sizeof(crc32_backup));
521 	memset(&pgpt_head->header_crc32, 0, sizeof(pgpt_head->header_crc32));
522 
523 	calc_crc32 = efi_crc32((const unsigned char *)pgpt_head,
524 		le32_to_cpu(pgpt_head->header_size));
525 
526 	memcpy(&pgpt_head->header_crc32, &crc32_backup, sizeof(crc32_backup));
527 
528 	if (calc_crc32 != le32_to_cpu(crc32_backup)) {
529 		printf("GUID Partition Table Header CRC is wrong:"
530 			"0x%x != 0x%x\n",
531 		       le32_to_cpu(crc32_backup), calc_crc32);
532 		return 0;
533 	}
534 
535 	/* Check that the my_lba entry points to the LBA that contains the GPT */
536 	if (le64_to_cpu(pgpt_head->my_lba) != lba) {
537 		printf("GPT: my_lba incorrect: %llX != %llX\n",
538 			le64_to_cpu(pgpt_head->my_lba),
539 			lba);
540 		return 0;
541 	}
542 
543 	/* Check the first_usable_lba and last_usable_lba are within the disk. */
544 	lastlba = (u64)dev_desc->lba;
545 	if (le64_to_cpu(pgpt_head->first_usable_lba) > lastlba) {
546 		printf("GPT: first_usable_lba incorrect: %llX > %llX\n",
547 			le64_to_cpu(pgpt_head->first_usable_lba), lastlba);
548 		return 0;
549 	}
550 	if (le64_to_cpu(pgpt_head->last_usable_lba) > lastlba) {
551 		printf("GPT: last_usable_lba incorrect: %llX > %llX\n",
552 			le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
553 		return 0;
554 	}
555 
556 	debug("GPT: first_usable_lba: %llX last_usable_lba %llX last lba %llX\n",
557 		le64_to_cpu(pgpt_head->first_usable_lba),
558 		le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
559 
560 	/* Read and allocate Partition Table Entries */
561 	*pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
562 	if (*pgpt_pte == NULL) {
563 		printf("GPT: Failed to allocate memory for PTE\n");
564 		return 0;
565 	}
566 
567 	/* Check the GUID Partition Table Entry Array CRC */
568 	calc_crc32 = efi_crc32((const unsigned char *)*pgpt_pte,
569 		le32_to_cpu(pgpt_head->num_partition_entries) *
570 		le32_to_cpu(pgpt_head->sizeof_partition_entry));
571 
572 	if (calc_crc32 != le32_to_cpu(pgpt_head->partition_entry_array_crc32)) {
573 		printf("GUID Partition Table Entry Array CRC is wrong:"
574 			"0x%x != 0x%x\n",
575 			le32_to_cpu(pgpt_head->partition_entry_array_crc32),
576 			calc_crc32);
577 
578 		free(*pgpt_pte);
579 		return 0;
580 	}
581 
582 	/* We're done, all's well */
583 	return 1;
584 }
585 
586 /**
587  * alloc_read_gpt_entries(): reads partition entries from disk
588  * @dev_desc
589  * @gpt - GPT header
590  *
591  * Description: Returns ptes on success,  NULL on error.
592  * Allocates space for PTEs based on information found in @gpt.
593  * Notes: remember to free pte when you're done!
594  */
595 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
596 					 gpt_header * pgpt_head)
597 {
598 	size_t count = 0, blk_cnt;
599 	gpt_entry *pte = NULL;
600 
601 	if (!dev_desc || !pgpt_head) {
602 		printf("%s: Invalid Argument(s)\n", __func__);
603 		return NULL;
604 	}
605 
606 	count = le32_to_cpu(pgpt_head->num_partition_entries) *
607 		le32_to_cpu(pgpt_head->sizeof_partition_entry);
608 
609 	debug("%s: count = %u * %u = %zu\n", __func__,
610 	      (u32) le32_to_cpu(pgpt_head->num_partition_entries),
611 	      (u32) le32_to_cpu(pgpt_head->sizeof_partition_entry), count);
612 
613 	/* Allocate memory for PTE, remember to FREE */
614 	if (count != 0) {
615 		pte = memalign(ARCH_DMA_MINALIGN,
616 			       PAD_TO_BLOCKSIZE(count, dev_desc));
617 	}
618 
619 	if (count == 0 || pte == NULL) {
620 		printf("%s: ERROR: Can't allocate 0x%zX "
621 		       "bytes for GPT Entries\n",
622 			__func__, count);
623 		return NULL;
624 	}
625 
626 	/* Read GPT Entries from device */
627 	blk_cnt = BLOCK_CNT(count, dev_desc);
628 	if (dev_desc->block_read (dev_desc->dev,
629 		(lbaint_t)le64_to_cpu(pgpt_head->partition_entry_lba),
630 		(lbaint_t) (blk_cnt), pte)
631 		!= blk_cnt) {
632 
633 		printf("*** ERROR: Can't read GPT Entries ***\n");
634 		free(pte);
635 		return NULL;
636 	}
637 	return pte;
638 }
639 
640 /**
641  * is_pte_valid(): validates a single Partition Table Entry
642  * @gpt_entry - Pointer to a single Partition Table Entry
643  *
644  * Description: returns 1 if valid,  0 on error.
645  */
646 static int is_pte_valid(gpt_entry * pte)
647 {
648 	efi_guid_t unused_guid;
649 
650 	if (!pte) {
651 		printf("%s: Invalid Argument(s)\n", __func__);
652 		return 0;
653 	}
654 
655 	/* Only one validation for now:
656 	 * The GUID Partition Type != Unused Entry (ALL-ZERO)
657 	 */
658 	memset(unused_guid.b, 0, sizeof(unused_guid.b));
659 
660 	if (memcmp(pte->partition_type_guid.b, unused_guid.b,
661 		sizeof(unused_guid.b)) == 0) {
662 
663 		debug("%s: Found an unused PTE GUID at 0x%08X\n", __func__,
664 		      (unsigned int)(uintptr_t)pte);
665 
666 		return 0;
667 	} else {
668 		return 1;
669 	}
670 }
671 #endif
672