xref: /openbmc/u-boot/disk/part_efi.c (revision 69fdf900)
1 /*
2  * Copyright (C) 2008 RuggedCom, Inc.
3  * Richard Retanubun <RichardRetanubun@RuggedCom.com>
4  *
5  * See file CREDITS for list of people who contributed to this
6  * project.
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (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,
21  * MA 02111-1307 USA
22  */
23 
24 /*
25  * Problems with CONFIG_SYS_64BIT_LBA:
26  *
27  * struct disk_partition.start in include/part.h is sized as ulong.
28  * When CONFIG_SYS_64BIT_LBA is activated, lbaint_t changes from ulong to uint64_t.
29  * For now, it is cast back to ulong at assignment.
30  *
31  * This limits the maximum size of addressable storage to < 2 Terra Bytes
32  */
33 #include <asm/unaligned.h>
34 #include <common.h>
35 #include <command.h>
36 #include <ide.h>
37 #include <malloc.h>
38 #include <part_efi.h>
39 #include <linux/ctype.h>
40 
41 DECLARE_GLOBAL_DATA_PTR;
42 
43 #ifdef HAVE_BLOCK_DEVICE
44 /**
45  * efi_crc32() - EFI version of crc32 function
46  * @buf: buffer to calculate crc32 of
47  * @len - length of buf
48  *
49  * Description: Returns EFI-style CRC32 value for @buf
50  */
51 static inline u32 efi_crc32(const void *buf, u32 len)
52 {
53 	return crc32(0, buf, len);
54 }
55 
56 /*
57  * Private function prototypes
58  */
59 
60 static int pmbr_part_valid(struct partition *part);
61 static int is_pmbr_valid(legacy_mbr * mbr);
62 static int is_gpt_valid(block_dev_desc_t * dev_desc, unsigned long long lba,
63 				gpt_header * pgpt_head, gpt_entry ** pgpt_pte);
64 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
65 				gpt_header * pgpt_head);
66 static int is_pte_valid(gpt_entry * pte);
67 
68 static char *print_efiname(gpt_entry *pte)
69 {
70 	static char name[PARTNAME_SZ + 1];
71 	int i;
72 	for (i = 0; i < PARTNAME_SZ; i++) {
73 		u8 c;
74 		c = pte->partition_name[i] & 0xff;
75 		c = (c && !isprint(c)) ? '.' : c;
76 		name[i] = c;
77 	}
78 	name[PARTNAME_SZ] = 0;
79 	return name;
80 }
81 
82 static void uuid_string(unsigned char *uuid, char *str)
83 {
84 	static const u8 le[16] = {3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11,
85 				  12, 13, 14, 15};
86 	int i;
87 
88 	for (i = 0; i < 16; i++) {
89 		sprintf(str, "%02x", uuid[le[i]]);
90 		str += 2;
91 		switch (i) {
92 		case 3:
93 		case 5:
94 		case 7:
95 		case 9:
96 			*str++ = '-';
97 			break;
98 		}
99 	}
100 }
101 
102 static efi_guid_t system_guid = PARTITION_SYSTEM_GUID;
103 
104 static inline int is_bootable(gpt_entry *p)
105 {
106 	return p->attributes.fields.legacy_bios_bootable ||
107 		!memcmp(&(p->partition_type_guid), &system_guid,
108 			sizeof(efi_guid_t));
109 }
110 
111 #ifdef CONFIG_EFI_PARTITION
112 /*
113  * Public Functions (include/part.h)
114  */
115 
116 void print_part_efi(block_dev_desc_t * dev_desc)
117 {
118 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
119 	gpt_entry *gpt_pte = NULL;
120 	int i = 0;
121 	char uuid[37];
122 
123 	if (!dev_desc) {
124 		printf("%s: Invalid Argument(s)\n", __func__);
125 		return;
126 	}
127 	/* This function validates AND fills in the GPT header and PTE */
128 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
129 			 gpt_head, &gpt_pte) != 1) {
130 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
131 		return;
132 	}
133 
134 	debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
135 
136 	printf("Part\tStart LBA\tEnd LBA\t\tName\n");
137 	printf("\tAttributes\n");
138 	printf("\tType UUID\n");
139 	printf("\tPartition UUID\n");
140 
141 	for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
142 		/* Stop at the first non valid PTE */
143 		if (!is_pte_valid(&gpt_pte[i]))
144 			break;
145 
146 		printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
147 			le64_to_cpu(gpt_pte[i].starting_lba),
148 			le64_to_cpu(gpt_pte[i].ending_lba),
149 			print_efiname(&gpt_pte[i]));
150 		printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
151 		uuid_string(gpt_pte[i].partition_type_guid.b, uuid);
152 		printf("\ttype:\t%s\n", uuid);
153 		uuid_string(gpt_pte[i].unique_partition_guid.b, uuid);
154 		printf("\tuuid:\t%s\n", uuid);
155 	}
156 
157 	/* Remember to free pte */
158 	free(gpt_pte);
159 	return;
160 }
161 
162 int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
163 				disk_partition_t * info)
164 {
165 	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
166 	gpt_entry *gpt_pte = NULL;
167 
168 	/* "part" argument must be at least 1 */
169 	if (!dev_desc || !info || part < 1) {
170 		printf("%s: Invalid Argument(s)\n", __func__);
171 		return -1;
172 	}
173 
174 	/* This function validates AND fills in the GPT header and PTE */
175 	if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
176 			gpt_head, &gpt_pte) != 1) {
177 		printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
178 		return -1;
179 	}
180 
181 	if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
182 	    !is_pte_valid(&gpt_pte[part - 1])) {
183 		printf("%s: *** ERROR: Invalid partition number %d ***\n",
184 			__func__, part);
185 		return -1;
186 	}
187 
188 	/* The ulong casting limits the maximum disk size to 2 TB */
189 	info->start = (u64)le64_to_cpu(gpt_pte[part - 1].starting_lba);
190 	/* The ending LBA is inclusive, to calculate size, add 1 to it */
191 	info->size = ((u64)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1)
192 		     - info->start;
193 	info->blksz = dev_desc->blksz;
194 
195 	sprintf((char *)info->name, "%s",
196 			print_efiname(&gpt_pte[part - 1]));
197 	sprintf((char *)info->type, "U-Boot");
198 	info->bootable = is_bootable(&gpt_pte[part - 1]);
199 #ifdef CONFIG_PARTITION_UUIDS
200 	uuid_string(gpt_pte[part - 1].unique_partition_guid.b, info->uuid);
201 #endif
202 
203 	debug("%s: start 0x%lX, size 0x%lX, name %s", __func__,
204 		info->start, info->size, info->name);
205 
206 	/* Remember to free pte */
207 	free(gpt_pte);
208 	return 0;
209 }
210 
211 int test_part_efi(block_dev_desc_t * dev_desc)
212 {
213 	ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);
214 
215 	/* Read legacy MBR from block 0 and validate it */
216 	if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)legacymbr) != 1)
217 		|| (is_pmbr_valid(legacymbr) != 1)) {
218 		return -1;
219 	}
220 	return 0;
221 }
222 
223 /**
224  * set_protective_mbr(): Set the EFI protective MBR
225  * @param dev_desc - block device descriptor
226  *
227  * @return - zero on success, otherwise error
228  */
229 static int set_protective_mbr(block_dev_desc_t *dev_desc)
230 {
231 	legacy_mbr *p_mbr;
232 
233 	/* Setup the Protective MBR */
234 	p_mbr = calloc(1, sizeof(p_mbr));
235 	if (p_mbr == NULL) {
236 		printf("%s: calloc failed!\n", __func__);
237 		return -1;
238 	}
239 	/* Append signature */
240 	p_mbr->signature = MSDOS_MBR_SIGNATURE;
241 	p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
242 	p_mbr->partition_record[0].start_sect = 1;
243 	p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
244 
245 	/* Write MBR sector to the MMC device */
246 	if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
247 		printf("** Can't write to device %d **\n",
248 			dev_desc->dev);
249 		free(p_mbr);
250 		return -1;
251 	}
252 
253 	free(p_mbr);
254 	return 0;
255 }
256 
257 /**
258  * string_uuid(); Convert UUID stored as string to bytes
259  *
260  * @param uuid - UUID represented as string
261  * @param dst - GUID buffer
262  *
263  * @return return 0 on successful conversion
264  */
265 static int string_uuid(char *uuid, u8 *dst)
266 {
267 	efi_guid_t guid;
268 	u16 b, c, d;
269 	u64 e;
270 	u32 a;
271 	u8 *p;
272 	u8 i;
273 
274 	const u8 uuid_str_len = 36;
275 
276 	/* The UUID is written in text: */
277 	/* 1        9    14   19   24 */
278 	/* xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx */
279 
280 	debug("%s: uuid: %s\n", __func__, uuid);
281 
282 	if (strlen(uuid) != uuid_str_len)
283 		return -1;
284 
285 	for (i = 0; i < uuid_str_len; i++) {
286 		if ((i == 8) || (i == 13) || (i == 18) || (i == 23)) {
287 			if (uuid[i] != '-')
288 				return -1;
289 		} else {
290 			if (!isxdigit(uuid[i]))
291 				return -1;
292 		}
293 	}
294 
295 	a = (u32)simple_strtoul(uuid, NULL, 16);
296 	b = (u16)simple_strtoul(uuid + 9, NULL, 16);
297 	c = (u16)simple_strtoul(uuid + 14, NULL, 16);
298 	d = (u16)simple_strtoul(uuid + 19, NULL, 16);
299 	e = (u64)simple_strtoull(uuid + 24, NULL, 16);
300 
301 	p = (u8 *) &e;
302 	guid = EFI_GUID(a, b, c, d >> 8, d & 0xFF,
303 			*(p + 5), *(p + 4), *(p + 3),
304 			*(p + 2), *(p + 1) , *p);
305 
306 	memcpy(dst, guid.b, sizeof(efi_guid_t));
307 
308 	return 0;
309 }
310 
311 int write_gpt_table(block_dev_desc_t *dev_desc,
312 		gpt_header *gpt_h, gpt_entry *gpt_e)
313 {
314 	const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
315 					   * sizeof(gpt_entry)), dev_desc);
316 	u32 calc_crc32;
317 	u64 val;
318 
319 	debug("max lba: %x\n", (u32) dev_desc->lba);
320 	/* Setup the Protective MBR */
321 	if (set_protective_mbr(dev_desc) < 0)
322 		goto err;
323 
324 	/* Generate CRC for the Primary GPT Header */
325 	calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
326 			      le32_to_cpu(gpt_h->num_partition_entries) *
327 			      le32_to_cpu(gpt_h->sizeof_partition_entry));
328 	gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
329 
330 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
331 			      le32_to_cpu(gpt_h->header_size));
332 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
333 
334 	/* Write the First GPT to the block right after the Legacy MBR */
335 	if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
336 		goto err;
337 
338 	if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_cnt, gpt_e)
339 	    != pte_blk_cnt)
340 		goto err;
341 
342 	/* recalculate the values for the Second GPT Header */
343 	val = le64_to_cpu(gpt_h->my_lba);
344 	gpt_h->my_lba = gpt_h->alternate_lba;
345 	gpt_h->alternate_lba = cpu_to_le64(val);
346 	gpt_h->header_crc32 = 0;
347 
348 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
349 			      le32_to_cpu(gpt_h->header_size));
350 	gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
351 
352 	if (dev_desc->block_write(dev_desc->dev,
353 				  le32_to_cpu(gpt_h->last_usable_lba + 1),
354 				  pte_blk_cnt, gpt_e) != pte_blk_cnt)
355 		goto err;
356 
357 	if (dev_desc->block_write(dev_desc->dev,
358 				  le32_to_cpu(gpt_h->my_lba), 1, gpt_h) != 1)
359 		goto err;
360 
361 	debug("GPT successfully written to block device!\n");
362 	return 0;
363 
364  err:
365 	printf("** Can't write to device %d **\n", dev_desc->dev);
366 	return -1;
367 }
368 
369 int gpt_fill_pte(gpt_header *gpt_h, gpt_entry *gpt_e,
370 		disk_partition_t *partitions, int parts)
371 {
372 	u32 offset = (u32)le32_to_cpu(gpt_h->first_usable_lba);
373 	ulong start;
374 	int i, k;
375 	size_t efiname_len, dosname_len;
376 #ifdef CONFIG_PARTITION_UUIDS
377 	char *str_uuid;
378 #endif
379 
380 	for (i = 0; i < parts; i++) {
381 		/* partition starting lba */
382 		start = partitions[i].start;
383 		if (start && (start < offset)) {
384 			printf("Partition overlap\n");
385 			return -1;
386 		}
387 		if (start) {
388 			gpt_e[i].starting_lba = cpu_to_le64(start);
389 			offset = start + partitions[i].size;
390 		} else {
391 			gpt_e[i].starting_lba = cpu_to_le64(offset);
392 			offset += partitions[i].size;
393 		}
394 		if (offset >= gpt_h->last_usable_lba) {
395 			printf("Partitions layout exceds disk size\n");
396 			return -1;
397 		}
398 		/* partition ending lba */
399 		if ((i == parts - 1) && (partitions[i].size == 0))
400 			/* extend the last partition to maximuim */
401 			gpt_e[i].ending_lba = gpt_h->last_usable_lba;
402 		else
403 			gpt_e[i].ending_lba = cpu_to_le64(offset - 1);
404 
405 		/* partition type GUID */
406 		memcpy(gpt_e[i].partition_type_guid.b,
407 			&PARTITION_BASIC_DATA_GUID, 16);
408 
409 #ifdef CONFIG_PARTITION_UUIDS
410 		str_uuid = partitions[i].uuid;
411 		if (string_uuid(str_uuid, gpt_e[i].unique_partition_guid.b)) {
412 			printf("Partition no. %d: invalid guid: %s\n",
413 				i, str_uuid);
414 			return -1;
415 		}
416 #endif
417 
418 		/* partition attributes */
419 		memset(&gpt_e[i].attributes, 0,
420 		       sizeof(gpt_entry_attributes));
421 
422 		/* partition name */
423 		efiname_len = sizeof(gpt_e[i].partition_name)
424 			/ sizeof(efi_char16_t);
425 		dosname_len = sizeof(partitions[i].name);
426 
427 		memset(gpt_e[i].partition_name, 0,
428 		       sizeof(gpt_e[i].partition_name));
429 
430 		for (k = 0; k < min(dosname_len, efiname_len); k++)
431 			gpt_e[i].partition_name[k] =
432 				(efi_char16_t)(partitions[i].name[k]);
433 
434 		debug("%s: name: %s offset[%d]: 0x%x size[%d]: 0x%lx\n",
435 		      __func__, partitions[i].name, i,
436 		      offset, i, partitions[i].size);
437 	}
438 
439 	return 0;
440 }
441 
442 int gpt_fill_header(block_dev_desc_t *dev_desc, gpt_header *gpt_h,
443 		char *str_guid, int parts_count)
444 {
445 	gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
446 	gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
447 	gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
448 	gpt_h->my_lba = cpu_to_le64(1);
449 	gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
450 	gpt_h->first_usable_lba = cpu_to_le64(34);
451 	gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
452 	gpt_h->partition_entry_lba = cpu_to_le64(2);
453 	gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
454 	gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
455 	gpt_h->header_crc32 = 0;
456 	gpt_h->partition_entry_array_crc32 = 0;
457 
458 	if (string_uuid(str_guid, gpt_h->disk_guid.b))
459 		return -1;
460 
461 	return 0;
462 }
463 
464 int gpt_restore(block_dev_desc_t *dev_desc, char *str_disk_guid,
465 		disk_partition_t *partitions, int parts_count)
466 {
467 	int ret;
468 
469 	gpt_header *gpt_h = calloc(1, PAD_TO_BLOCKSIZE(sizeof(gpt_header),
470 						       dev_desc));
471 	gpt_entry *gpt_e;
472 
473 	if (gpt_h == NULL) {
474 		printf("%s: calloc failed!\n", __func__);
475 		return -1;
476 	}
477 
478 	gpt_e = calloc(1, PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS
479 					       * sizeof(gpt_entry),
480 					       dev_desc));
481 	if (gpt_e == NULL) {
482 		printf("%s: calloc failed!\n", __func__);
483 		free(gpt_h);
484 		return -1;
485 	}
486 
487 	/* Generate Primary GPT header (LBA1) */
488 	ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
489 	if (ret)
490 		goto err;
491 
492 	/* Generate partition entries */
493 	ret = gpt_fill_pte(gpt_h, gpt_e, partitions, parts_count);
494 	if (ret)
495 		goto err;
496 
497 	/* Write GPT partition table */
498 	ret = write_gpt_table(dev_desc, gpt_h, gpt_e);
499 
500 err:
501 	free(gpt_e);
502 	free(gpt_h);
503 	return ret;
504 }
505 #endif
506 
507 /*
508  * Private functions
509  */
510 /*
511  * pmbr_part_valid(): Check for EFI partition signature
512  *
513  * Returns: 1 if EFI GPT partition type is found.
514  */
515 static int pmbr_part_valid(struct partition *part)
516 {
517 	if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
518 		get_unaligned_le32(&part->start_sect) == 1UL) {
519 		return 1;
520 	}
521 
522 	return 0;
523 }
524 
525 /*
526  * is_pmbr_valid(): test Protective MBR for validity
527  *
528  * Returns: 1 if PMBR is valid, 0 otherwise.
529  * Validity depends on two things:
530  *  1) MSDOS signature is in the last two bytes of the MBR
531  *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
532  */
533 static int is_pmbr_valid(legacy_mbr * mbr)
534 {
535 	int i = 0;
536 
537 	if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
538 		return 0;
539 
540 	for (i = 0; i < 4; i++) {
541 		if (pmbr_part_valid(&mbr->partition_record[i])) {
542 			return 1;
543 		}
544 	}
545 	return 0;
546 }
547 
548 /**
549  * is_gpt_valid() - tests one GPT header and PTEs for validity
550  *
551  * lba is the logical block address of the GPT header to test
552  * gpt is a GPT header ptr, filled on return.
553  * ptes is a PTEs ptr, filled on return.
554  *
555  * Description: returns 1 if valid,  0 on error.
556  * If valid, returns pointers to PTEs.
557  */
558 static int is_gpt_valid(block_dev_desc_t * dev_desc, unsigned long long lba,
559 			gpt_header * pgpt_head, gpt_entry ** pgpt_pte)
560 {
561 	u32 crc32_backup = 0;
562 	u32 calc_crc32;
563 	unsigned long long lastlba;
564 
565 	if (!dev_desc || !pgpt_head) {
566 		printf("%s: Invalid Argument(s)\n", __func__);
567 		return 0;
568 	}
569 
570 	/* Read GPT Header from device */
571 	if (dev_desc->block_read(dev_desc->dev, lba, 1, pgpt_head) != 1) {
572 		printf("*** ERROR: Can't read GPT header ***\n");
573 		return 0;
574 	}
575 
576 	/* Check the GPT header signature */
577 	if (le64_to_cpu(pgpt_head->signature) != GPT_HEADER_SIGNATURE) {
578 		printf("GUID Partition Table Header signature is wrong:"
579 			"0x%llX != 0x%llX\n",
580 			le64_to_cpu(pgpt_head->signature),
581 			GPT_HEADER_SIGNATURE);
582 		return 0;
583 	}
584 
585 	/* Check the GUID Partition Table CRC */
586 	memcpy(&crc32_backup, &pgpt_head->header_crc32, sizeof(crc32_backup));
587 	memset(&pgpt_head->header_crc32, 0, sizeof(pgpt_head->header_crc32));
588 
589 	calc_crc32 = efi_crc32((const unsigned char *)pgpt_head,
590 		le32_to_cpu(pgpt_head->header_size));
591 
592 	memcpy(&pgpt_head->header_crc32, &crc32_backup, sizeof(crc32_backup));
593 
594 	if (calc_crc32 != le32_to_cpu(crc32_backup)) {
595 		printf("GUID Partition Table Header CRC is wrong:"
596 			"0x%x != 0x%x\n",
597 		       le32_to_cpu(crc32_backup), calc_crc32);
598 		return 0;
599 	}
600 
601 	/* Check that the my_lba entry points to the LBA that contains the GPT */
602 	if (le64_to_cpu(pgpt_head->my_lba) != lba) {
603 		printf("GPT: my_lba incorrect: %llX != %llX\n",
604 			le64_to_cpu(pgpt_head->my_lba),
605 			lba);
606 		return 0;
607 	}
608 
609 	/* Check the first_usable_lba and last_usable_lba are within the disk. */
610 	lastlba = (unsigned long long)dev_desc->lba;
611 	if (le64_to_cpu(pgpt_head->first_usable_lba) > lastlba) {
612 		printf("GPT: first_usable_lba incorrect: %llX > %llX\n",
613 			le64_to_cpu(pgpt_head->first_usable_lba), lastlba);
614 		return 0;
615 	}
616 	if (le64_to_cpu(pgpt_head->last_usable_lba) > lastlba) {
617 		printf("GPT: last_usable_lba incorrect: %llX > %llX\n",
618 			(u64) le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
619 		return 0;
620 	}
621 
622 	debug("GPT: first_usable_lba: %llX last_usable_lba %llX last lba %llX\n",
623 		le64_to_cpu(pgpt_head->first_usable_lba),
624 		le64_to_cpu(pgpt_head->last_usable_lba), lastlba);
625 
626 	/* Read and allocate Partition Table Entries */
627 	*pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
628 	if (*pgpt_pte == NULL) {
629 		printf("GPT: Failed to allocate memory for PTE\n");
630 		return 0;
631 	}
632 
633 	/* Check the GUID Partition Table Entry Array CRC */
634 	calc_crc32 = efi_crc32((const unsigned char *)*pgpt_pte,
635 		le32_to_cpu(pgpt_head->num_partition_entries) *
636 		le32_to_cpu(pgpt_head->sizeof_partition_entry));
637 
638 	if (calc_crc32 != le32_to_cpu(pgpt_head->partition_entry_array_crc32)) {
639 		printf("GUID Partition Table Entry Array CRC is wrong:"
640 			"0x%x != 0x%x\n",
641 			le32_to_cpu(pgpt_head->partition_entry_array_crc32),
642 			calc_crc32);
643 
644 		free(*pgpt_pte);
645 		return 0;
646 	}
647 
648 	/* We're done, all's well */
649 	return 1;
650 }
651 
652 /**
653  * alloc_read_gpt_entries(): reads partition entries from disk
654  * @dev_desc
655  * @gpt - GPT header
656  *
657  * Description: Returns ptes on success,  NULL on error.
658  * Allocates space for PTEs based on information found in @gpt.
659  * Notes: remember to free pte when you're done!
660  */
661 static gpt_entry *alloc_read_gpt_entries(block_dev_desc_t * dev_desc,
662 					 gpt_header * pgpt_head)
663 {
664 	size_t count = 0, blk_cnt;
665 	gpt_entry *pte = NULL;
666 
667 	if (!dev_desc || !pgpt_head) {
668 		printf("%s: Invalid Argument(s)\n", __func__);
669 		return NULL;
670 	}
671 
672 	count = le32_to_cpu(pgpt_head->num_partition_entries) *
673 		le32_to_cpu(pgpt_head->sizeof_partition_entry);
674 
675 	debug("%s: count = %u * %u = %zu\n", __func__,
676 	      (u32) le32_to_cpu(pgpt_head->num_partition_entries),
677 	      (u32) le32_to_cpu(pgpt_head->sizeof_partition_entry), count);
678 
679 	/* Allocate memory for PTE, remember to FREE */
680 	if (count != 0) {
681 		pte = memalign(ARCH_DMA_MINALIGN,
682 			       PAD_TO_BLOCKSIZE(count, dev_desc));
683 	}
684 
685 	if (count == 0 || pte == NULL) {
686 		printf("%s: ERROR: Can't allocate 0x%zX "
687 		       "bytes for GPT Entries\n",
688 			__func__, count);
689 		return NULL;
690 	}
691 
692 	/* Read GPT Entries from device */
693 	blk_cnt = BLOCK_CNT(count, dev_desc);
694 	if (dev_desc->block_read (dev_desc->dev,
695 		le64_to_cpu(pgpt_head->partition_entry_lba),
696 		(lbaint_t) (blk_cnt), pte)
697 		!= blk_cnt) {
698 
699 		printf("*** ERROR: Can't read GPT Entries ***\n");
700 		free(pte);
701 		return NULL;
702 	}
703 	return pte;
704 }
705 
706 /**
707  * is_pte_valid(): validates a single Partition Table Entry
708  * @gpt_entry - Pointer to a single Partition Table Entry
709  *
710  * Description: returns 1 if valid,  0 on error.
711  */
712 static int is_pte_valid(gpt_entry * pte)
713 {
714 	efi_guid_t unused_guid;
715 
716 	if (!pte) {
717 		printf("%s: Invalid Argument(s)\n", __func__);
718 		return 0;
719 	}
720 
721 	/* Only one validation for now:
722 	 * The GUID Partition Type != Unused Entry (ALL-ZERO)
723 	 */
724 	memset(unused_guid.b, 0, sizeof(unused_guid.b));
725 
726 	if (memcmp(pte->partition_type_guid.b, unused_guid.b,
727 		sizeof(unused_guid.b)) == 0) {
728 
729 		debug("%s: Found an unused PTE GUID at 0x%08X\n", __func__,
730 		      (unsigned int)(uintptr_t)pte);
731 
732 		return 0;
733 	} else {
734 		return 1;
735 	}
736 }
737 #endif
738