part: Allow setting the partition-table type

[thirdparty/u-boot.git] / disk / part_efi.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2008 RuggedCom, Inc.
 * Richard Retanubun <RichardRetanubun@RuggedCom.com>
 */

/*
 * NOTE:
 *   when CONFIG_SYS_64BIT_LBA is not defined, lbaint_t is 32 bits; this
 *   limits the maximum size of addressable storage to < 2 tebibytes
 */
#include <common.h>
#include <blk.h>
#include <log.h>
#include <part.h>
#include <uuid.h>
#include <asm/cache.h>
#include <asm/global_data.h>
#include <asm/unaligned.h>
#include <command.h>
#include <fdtdec.h>
#include <ide.h>
#include <malloc.h>
#include <memalign.h>
#include <part_efi.h>
#include <dm/ofnode.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <u-boot/crc.h>

/* GUID for basic data partitons */
#if CONFIG_IS_ENABLED(EFI_PARTITION)
static const efi_guid_t partition_basic_data_guid = PARTITION_BASIC_DATA_GUID;
#endif

/**
 * efi_crc32() - EFI version of crc32 function
 * @buf: buffer to calculate crc32 of
 * @len - length of buf
 *
 * Description: Returns EFI-style CRC32 value for @buf
 */
static inline u32 efi_crc32(const void *buf, u32 len)
{
        return crc32(0, buf, len);
}

/*
 * Private function prototypes
 */

static int pmbr_part_valid(struct partition *part);
static int is_pmbr_valid(legacy_mbr * mbr);
static int is_gpt_valid(struct blk_desc *dev_desc, u64 lba,
                                gpt_header *pgpt_head, gpt_entry **pgpt_pte);
static gpt_entry *alloc_read_gpt_entries(struct blk_desc *dev_desc,
                                         gpt_header *pgpt_head);
static int is_pte_valid(gpt_entry * pte);
static int find_valid_gpt(struct blk_desc *dev_desc, gpt_header *gpt_head,
                          gpt_entry **pgpt_pte);

static char *print_efiname(gpt_entry *pte)
{
        static char name[PARTNAME_SZ + 1];
        int i;
        for (i = 0; i < PARTNAME_SZ; i++) {
                u8 c;
                c = pte->partition_name[i] & 0xff;
                c = (c && !isprint(c)) ? '.' : c;
                name[i] = c;
        }
        name[PARTNAME_SZ] = 0;
        return name;
}

static const efi_guid_t system_guid = PARTITION_SYSTEM_GUID;

static int get_bootable(gpt_entry *p)
{
        int ret = 0;

        if (!memcmp(&p->partition_type_guid, &system_guid, sizeof(efi_guid_t)))
                ret |=  PART_EFI_SYSTEM_PARTITION;
        if (p->attributes.fields.legacy_bios_bootable)
                ret |=  PART_BOOTABLE;
        return ret;
}

static int validate_gpt_header(gpt_header *gpt_h, lbaint_t lba,
                lbaint_t lastlba)
{
        uint32_t crc32_backup = 0;
        uint32_t calc_crc32;

        /* Check the GPT header signature */
        if (le64_to_cpu(gpt_h->signature) != GPT_HEADER_SIGNATURE_UBOOT) {
                log_debug("%s signature is wrong: %#llX != %#llX\n",
                          "GUID Partition Table Header",
                          le64_to_cpu(gpt_h->signature),
                          GPT_HEADER_SIGNATURE_UBOOT);
                return -1;
        }

        /* Check the GUID Partition Table CRC */
        memcpy(&crc32_backup, &gpt_h->header_crc32, sizeof(crc32_backup));
        memset(&gpt_h->header_crc32, 0, sizeof(gpt_h->header_crc32));

        calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
                le32_to_cpu(gpt_h->header_size));

        memcpy(&gpt_h->header_crc32, &crc32_backup, sizeof(crc32_backup));

        if (calc_crc32 != le32_to_cpu(crc32_backup)) {
                log_debug("%s: CRC is wrong: %#x != %#x\n",
                          "GUID Partition Table Header",
                          le32_to_cpu(crc32_backup), calc_crc32);
                return -1;
        }

        /*
         * Check that the my_lba entry points to the LBA that contains the GPT
         */
        if (le64_to_cpu(gpt_h->my_lba) != lba) {
                log_debug("GPT: my_lba incorrect: %llX != " LBAF "\n",
                          le64_to_cpu(gpt_h->my_lba), lba);
                return -1;
        }

        /*
         * Check that the first_usable_lba and that the last_usable_lba are
         * within the disk.
         */
        if (le64_to_cpu(gpt_h->first_usable_lba) > lastlba) {
                log_debug("GPT: first_usable_lba incorrect: %llX > " LBAF "\n",
                          le64_to_cpu(gpt_h->first_usable_lba), lastlba);
                return -1;
        }
        if (le64_to_cpu(gpt_h->last_usable_lba) > lastlba) {
                log_debug("GPT: last_usable_lba incorrect: %llX > " LBAF "\n",
                          le64_to_cpu(gpt_h->last_usable_lba), lastlba);
                return -1;
        }

        debug("GPT: first_usable_lba: %llX last_usable_lba: %llX last lba: "
              LBAF "\n", le64_to_cpu(gpt_h->first_usable_lba),
              le64_to_cpu(gpt_h->last_usable_lba), lastlba);

        return 0;
}

static int validate_gpt_entries(gpt_header *gpt_h, gpt_entry *gpt_e)
{
        uint32_t calc_crc32;

        /* Check the GUID Partition Table Entry Array CRC */
        calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
                le32_to_cpu(gpt_h->num_partition_entries) *
                le32_to_cpu(gpt_h->sizeof_partition_entry));

        if (calc_crc32 != le32_to_cpu(gpt_h->partition_entry_array_crc32)) {
                log_debug("%s: %#x != %#x\n",
                          "GUID Partition Table Entry Array CRC is wrong",
                          le32_to_cpu(gpt_h->partition_entry_array_crc32),
                          calc_crc32);
                return -1;
        }

        return 0;
}

static void prepare_backup_gpt_header(gpt_header *gpt_h)
{
        uint32_t calc_crc32;
        uint64_t val;

        /* recalculate the values for the Backup GPT Header */
        val = le64_to_cpu(gpt_h->my_lba);
        gpt_h->my_lba = gpt_h->alternate_lba;
        gpt_h->alternate_lba = cpu_to_le64(val);
        gpt_h->partition_entry_lba =
                        cpu_to_le64(le64_to_cpu(gpt_h->last_usable_lba) + 1);
        gpt_h->header_crc32 = 0;

        calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
                               le32_to_cpu(gpt_h->header_size));
        gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
}

#if CONFIG_IS_ENABLED(EFI_PARTITION)
/*
 * Public Functions (include/part.h)
 */

/*
 * UUID is displayed as 32 hexadecimal digits, in 5 groups,
 * separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters
 */
int get_disk_guid(struct blk_desc * dev_desc, char *guid)
{
        ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
        gpt_entry *gpt_pte = NULL;
        unsigned char *guid_bin;

        /* This function validates AND fills in the GPT header and PTE */
        if (find_valid_gpt(dev_desc, gpt_head, &gpt_pte) != 1)
                return -EINVAL;

        guid_bin = gpt_head->disk_guid.b;
        uuid_bin_to_str(guid_bin, guid, UUID_STR_FORMAT_GUID);

        /* Remember to free pte */
        free(gpt_pte);
        return 0;
}

void part_print_efi(struct blk_desc *dev_desc)
{
        ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
        gpt_entry *gpt_pte = NULL;
        int i = 0;
        unsigned char *uuid;

        /* This function validates AND fills in the GPT header and PTE */
        if (find_valid_gpt(dev_desc, gpt_head, &gpt_pte) != 1)
                return;

        debug("%s: gpt-entry at %p\n", __func__, gpt_pte);

        printf("Part\tStart LBA\tEnd LBA\t\tName\n");
        printf("\tAttributes\n");
        printf("\tType GUID\n");
        printf("\tPartition GUID\n");

        for (i = 0; i < le32_to_cpu(gpt_head->num_partition_entries); i++) {
                /* Skip invalid PTE */
                if (!is_pte_valid(&gpt_pte[i]))
                        continue;

                printf("%3d\t0x%08llx\t0x%08llx\t\"%s\"\n", (i + 1),
                        le64_to_cpu(gpt_pte[i].starting_lba),
                        le64_to_cpu(gpt_pte[i].ending_lba),
                        print_efiname(&gpt_pte[i]));
                printf("\tattrs:\t0x%016llx\n", gpt_pte[i].attributes.raw);
                uuid = (unsigned char *)gpt_pte[i].partition_type_guid.b;
                if (IS_ENABLED(CONFIG_PARTITION_TYPE_GUID))
                        printf("\ttype:\t%pUl\n\t\t(%pUs)\n", uuid, uuid);
                else
                        printf("\ttype:\t%pUl\n", uuid);
                uuid = (unsigned char *)gpt_pte[i].unique_partition_guid.b;
                printf("\tguid:\t%pUl\n", uuid);
        }

        /* Remember to free pte */
        free(gpt_pte);
        return;
}

int part_get_info_efi(struct blk_desc *dev_desc, int part,
                      struct disk_partition *info)
{
        ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1, dev_desc->blksz);
        gpt_entry *gpt_pte = NULL;

        /* "part" argument must be at least 1 */
        if (part < 1) {
                log_debug("Invalid Argument(s)\n");
                return -EINVAL;
        }

        /* This function validates AND fills in the GPT header and PTE */
        if (find_valid_gpt(dev_desc, gpt_head, &gpt_pte) != 1)
                return -EINVAL;

        if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
            !is_pte_valid(&gpt_pte[part - 1])) {
                log_debug("Invalid partition number %d\n", part);
                free(gpt_pte);
                return -EPERM;
        }

        /* The 'lbaint_t' casting may limit the maximum disk size to 2 TB */
        info->start = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].starting_lba);
        /* The ending LBA is inclusive, to calculate size, add 1 to it */
        info->size = (lbaint_t)le64_to_cpu(gpt_pte[part - 1].ending_lba) + 1
                     - info->start;
        info->blksz = dev_desc->blksz;

        snprintf((char *)info->name, sizeof(info->name), "%s",
                 print_efiname(&gpt_pte[part - 1]));
        strcpy((char *)info->type, "U-Boot");
        info->bootable = get_bootable(&gpt_pte[part - 1]);
#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
        uuid_bin_to_str(gpt_pte[part - 1].unique_partition_guid.b, info->uuid,
                        UUID_STR_FORMAT_GUID);
#endif
#ifdef CONFIG_PARTITION_TYPE_GUID
        uuid_bin_to_str(gpt_pte[part - 1].partition_type_guid.b,
                        info->type_guid, UUID_STR_FORMAT_GUID);
#endif

        log_debug("start 0x" LBAF ", size 0x" LBAF ", name %s\n", info->start,
                  info->size, info->name);

        /* Remember to free pte */
        free(gpt_pte);
        return 0;
}

static int part_test_efi(struct blk_desc *dev_desc)
{
        ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, legacymbr, 1, dev_desc->blksz);

        /* Read legacy MBR from block 0 and validate it */
        if ((blk_dread(dev_desc, 0, 1, (ulong *)legacymbr) != 1)
                || (is_pmbr_valid(legacymbr) != 1)) {
                return -1;
        }
        return 0;
}

/**
 * set_protective_mbr(): Set the EFI protective MBR
 * @param dev_desc - block device descriptor
 *
 * Return: - zero on success, otherwise error
 */
static int set_protective_mbr(struct blk_desc *dev_desc)
{
        /* Setup the Protective MBR */
        ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, p_mbr, 1, dev_desc->blksz);
        if (p_mbr == NULL) {
                log_debug("calloc failed!\n");
                return -ENOMEM;
        }

        /* Read MBR to backup boot code if it exists */
        if (blk_dread(dev_desc, 0, 1, p_mbr) != 1) {
                log_debug("** Can't read from device %d **\n",
                          dev_desc->devnum);
                return -EIO;
        }

        /* Clear all data in MBR except of backed up boot code */
        memset((char *)p_mbr + MSDOS_MBR_BOOT_CODE_SIZE, 0, sizeof(*p_mbr) -
                        MSDOS_MBR_BOOT_CODE_SIZE);

        /* Append signature */
        p_mbr->signature = MSDOS_MBR_SIGNATURE;
        p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
        p_mbr->partition_record[0].start_sect = 1;
        p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba - 1;

        /* Write MBR sector to the MMC device */
        if (blk_dwrite(dev_desc, 0, 1, p_mbr) != 1) {
                log_debug("** Can't write to device %d **\n", dev_desc->devnum);
                return -EIO;
        }

        return 0;
}

int write_gpt_table(struct blk_desc *dev_desc,
                gpt_header *gpt_h, gpt_entry *gpt_e)
{
        const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
                                           * sizeof(gpt_entry)), dev_desc);
        u32 calc_crc32;

        debug("max lba: %x\n", (u32) dev_desc->lba);
        /* Setup the Protective MBR */
        if (set_protective_mbr(dev_desc) < 0)
                goto err;

        /* Generate CRC for the Primary GPT Header */
        calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
                              le32_to_cpu(gpt_h->num_partition_entries) *
                              le32_to_cpu(gpt_h->sizeof_partition_entry));
        gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);

        calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
                              le32_to_cpu(gpt_h->header_size));
        gpt_h->header_crc32 = cpu_to_le32(calc_crc32);

        /* Write the First GPT to the block right after the Legacy MBR */
        if (blk_dwrite(dev_desc, 1, 1, gpt_h) != 1)
                goto err;

        if (blk_dwrite(dev_desc, le64_to_cpu(gpt_h->partition_entry_lba),
                       pte_blk_cnt, gpt_e) != pte_blk_cnt)
                goto err;

        prepare_backup_gpt_header(gpt_h);

        if (blk_dwrite(dev_desc, (lbaint_t)le64_to_cpu(gpt_h->last_usable_lba)
                       + 1, pte_blk_cnt, gpt_e) != pte_blk_cnt)
                goto err;

        if (blk_dwrite(dev_desc, (lbaint_t)le64_to_cpu(gpt_h->my_lba), 1,
                       gpt_h) != 1)
                goto err;

        debug("GPT successfully written to block device!\n");
        return 0;

 err:
        log_debug("** Can't write to device %d **\n", dev_desc->devnum);
        return -EIO;
}

int gpt_fill_pte(struct blk_desc *dev_desc,
                 gpt_header *gpt_h, gpt_entry *gpt_e,
                 struct disk_partition *partitions, int parts)
{
        lbaint_t offset = (lbaint_t)le64_to_cpu(gpt_h->first_usable_lba);
        lbaint_t last_usable_lba = (lbaint_t)
                        le64_to_cpu(gpt_h->last_usable_lba);
        int i, k;
        size_t efiname_len, dosname_len;
#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
        char *str_uuid;
        unsigned char *bin_uuid;
#endif
#ifdef CONFIG_PARTITION_TYPE_GUID
        char *str_type_guid;
        unsigned char *bin_type_guid;
#endif
        size_t hdr_start = gpt_h->my_lba;
        size_t hdr_end = hdr_start + 1;

        size_t pte_start = gpt_h->partition_entry_lba;
        size_t pte_end = pte_start +
                gpt_h->num_partition_entries * gpt_h->sizeof_partition_entry /
                dev_desc->blksz;

        for (i = 0; i < parts; i++) {
                /* partition starting lba */
                lbaint_t start = partitions[i].start;
                lbaint_t size = partitions[i].size;

                if (start) {
                        offset = start + size;
                } else {
                        start = offset;
                        offset += size;
                }

                /*
                 * If our partition overlaps with either the GPT
                 * header, or the partition entry, reject it.
                 */
                if (((start < hdr_end && hdr_start < (start + size)) ||
                     (start < pte_end && pte_start < (start + size)))) {
                        log_debug("Partition overlap\n");
                        return -ENOSPC;
                }

                gpt_e[i].starting_lba = cpu_to_le64(start);

                if (offset > (last_usable_lba + 1)) {
                        log_debug("Partitions layout exceeds disk size\n");
                        return -E2BIG;
                }
                /* partition ending lba */
                if ((i == parts - 1) && (size == 0))
                        /* extend the last partition to maximuim */
                        gpt_e[i].ending_lba = gpt_h->last_usable_lba;
                else
                        gpt_e[i].ending_lba = cpu_to_le64(offset - 1);

#ifdef CONFIG_PARTITION_TYPE_GUID
                str_type_guid = partitions[i].type_guid;
                bin_type_guid = gpt_e[i].partition_type_guid.b;
                if (strlen(str_type_guid)) {
                        if (uuid_str_to_bin(str_type_guid, bin_type_guid,
                                            UUID_STR_FORMAT_GUID)) {
                                log_debug("Partition no. %d: invalid type guid: %s\n",
                                          i, str_type_guid);
                                return -EINVAL;
                        }
                } else {
                        /* default partition type GUID */
                        memcpy(bin_type_guid,
                               &partition_basic_data_guid, 16);
                }
#else
                /* partition type GUID */
                memcpy(gpt_e[i].partition_type_guid.b,
                        &partition_basic_data_guid, 16);
#endif

#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
                str_uuid = partitions[i].uuid;
                bin_uuid = gpt_e[i].unique_partition_guid.b;

                if (uuid_str_to_bin(str_uuid, bin_uuid, UUID_STR_FORMAT_GUID)) {
                        log_debug("Partition no. %d: invalid guid: %s\n",
                                  i, str_uuid);
                        return -EINVAL;
                }
#endif

                /* partition attributes */
                memset(&gpt_e[i].attributes, 0,
                       sizeof(gpt_entry_attributes));

                if (partitions[i].bootable & PART_BOOTABLE)
                        gpt_e[i].attributes.fields.legacy_bios_bootable = 1;

                /* partition name */
                efiname_len = sizeof(gpt_e[i].partition_name)
                        / sizeof(efi_char16_t);
                dosname_len = sizeof(partitions[i].name);

                memset(gpt_e[i].partition_name, 0,
                       sizeof(gpt_e[i].partition_name));

                for (k = 0; k < min(dosname_len, efiname_len); k++)
                        gpt_e[i].partition_name[k] =
                                (efi_char16_t)(partitions[i].name[k]);

                debug("%s: name: %s offset[%d]: 0x" LBAF
                      " size[%d]: 0x" LBAF "\n",
                      __func__, partitions[i].name, i,
                      offset, i, size);
        }

        return 0;
}

static uint32_t partition_entries_offset(struct blk_desc *dev_desc)
{
        uint32_t offset_blks = 2;
        uint32_t __maybe_unused offset_bytes;
        int __maybe_unused config_offset;

#if defined(CONFIG_EFI_PARTITION_ENTRIES_OFF)
        /*
         * Some architectures require their SPL loader at a fixed
         * address within the first 16KB of the disk.  To avoid an
         * overlap with the partition entries of the EFI partition
         * table, the first safe offset (in bytes, from the start of
         * the disk) for the entries can be set in
         * CONFIG_EFI_PARTITION_ENTRIES_OFF.
         */
        offset_bytes =
                PAD_TO_BLOCKSIZE(CONFIG_EFI_PARTITION_ENTRIES_OFF, dev_desc);
        offset_blks = offset_bytes / dev_desc->blksz;
#endif

#if defined(CONFIG_OF_CONTROL)
        /*
         * Allow the offset of the first partition entires (in bytes
         * from the start of the device) to be specified as a property
         * of the device tree '/config' node.
         */
        config_offset = ofnode_conf_read_int(
                "u-boot,efi-partition-entries-offset", -EINVAL);
        if (config_offset != -EINVAL) {
                offset_bytes = PAD_TO_BLOCKSIZE(config_offset, dev_desc);
                offset_blks = offset_bytes / dev_desc->blksz;
        }
#endif

        debug("efi: partition entries offset (in blocks): %d\n", offset_blks);

        /*
         * The earliest LBA this can be at is LBA#2 (i.e. right behind
         * the (protective) MBR and the GPT header.
         */
        if (offset_blks < 2)
                offset_blks = 2;

        return offset_blks;
}

int gpt_fill_header(struct blk_desc *dev_desc, gpt_header *gpt_h,
                char *str_guid, int parts_count)
{
        gpt_h->signature = cpu_to_le64(GPT_HEADER_SIGNATURE_UBOOT);
        gpt_h->revision = cpu_to_le32(GPT_HEADER_REVISION_V1);
        gpt_h->header_size = cpu_to_le32(sizeof(gpt_header));
        gpt_h->my_lba = cpu_to_le64(1);
        gpt_h->alternate_lba = cpu_to_le64(dev_desc->lba - 1);
        gpt_h->last_usable_lba = cpu_to_le64(dev_desc->lba - 34);
        gpt_h->partition_entry_lba =
                cpu_to_le64(partition_entries_offset(dev_desc));
        gpt_h->first_usable_lba =
                cpu_to_le64(le64_to_cpu(gpt_h->partition_entry_lba) + 32);
        gpt_h->num_partition_entries = cpu_to_le32(GPT_ENTRY_NUMBERS);
        gpt_h->sizeof_partition_entry = cpu_to_le32(sizeof(gpt_entry));
        gpt_h->header_crc32 = 0;
        gpt_h->partition_entry_array_crc32 = 0;

        if (uuid_str_to_bin(str_guid, gpt_h->disk_guid.b, UUID_STR_FORMAT_GUID))
                return -1;

        return 0;
}

int gpt_restore(struct blk_desc *dev_desc, char *str_disk_guid,
                struct disk_partition *partitions, int parts_count)
{
        gpt_header *gpt_h;
        gpt_entry *gpt_e;
        int ret, size;

        size = PAD_TO_BLOCKSIZE(sizeof(gpt_header), dev_desc);
        gpt_h = malloc_cache_aligned(size);
        if (gpt_h == NULL) {
                log_debug("calloc failed!\n");
                return -ENOMEM;
        }
        memset(gpt_h, 0, size);

        size = PAD_TO_BLOCKSIZE(GPT_ENTRY_NUMBERS * sizeof(gpt_entry),
                                dev_desc);
        gpt_e = malloc_cache_aligned(size);
        if (gpt_e == NULL) {
                log_debug("calloc failed!\n");
                free(gpt_h);
                return -ENOMEM;
        }
        memset(gpt_e, 0, size);

        /* Generate Primary GPT header (LBA1) */
        ret = gpt_fill_header(dev_desc, gpt_h, str_disk_guid, parts_count);
        if (ret)
                goto err;

        /* Generate partition entries */
        ret = gpt_fill_pte(dev_desc, gpt_h, gpt_e, partitions, parts_count);
        if (ret)
                goto err;

        /* Write GPT partition table */
        ret = write_gpt_table(dev_desc, gpt_h, gpt_e);

err:
        free(gpt_e);
        free(gpt_h);
        return ret;
}

/**
 * gpt_convert_efi_name_to_char() - convert u16 string to char string
 *
 * TODO: this conversion only supports ANSI characters
 *
 * @s:  target buffer
 * @es: u16 string to be converted
 * @n:  size of target buffer
 */
static void gpt_convert_efi_name_to_char(char *s, void *es, int n)
{
        char *ess = es;
        int i, j;

        memset(s, '\0', n);

        for (i = 0, j = 0; j < n; i += 2, j++) {
                s[j] = ess[i];
                if (!ess[i])
                        return;
        }
}

int gpt_verify_headers(struct blk_desc *dev_desc, gpt_header *gpt_head,
                       gpt_entry **gpt_pte)
{
        /*
         * This function validates AND
         * fills in the GPT header and PTE
         */
        if (is_gpt_valid(dev_desc,
                         GPT_PRIMARY_PARTITION_TABLE_LBA,
                         gpt_head, gpt_pte) != 1) {
                log_debug("Invalid GPT\n");
                return -1;
        }

        /* Free pte before allocating again */
        free(*gpt_pte);

        /*
         * Check that the alternate_lba entry points to the last LBA
         */
        if (le64_to_cpu(gpt_head->alternate_lba) != (dev_desc->lba - 1)) {
                log_debug("Misplaced Backup GPT\n");
                return -1;
        }

        if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
                         gpt_head, gpt_pte) != 1) {
                log_debug("Invalid Backup GPT\n");
                return -1;
        }

        return 0;
}

static void restore_primary_gpt_header(gpt_header *gpt_h, struct blk_desc *dev_desc)
{
        u32 calc_crc32;
        u64 val;

        /* recalculate the values for the Primary GPT Header */
        val = le64_to_cpu(gpt_h->my_lba);
        gpt_h->my_lba = gpt_h->alternate_lba;
        gpt_h->alternate_lba = cpu_to_le64(val);
        gpt_h->partition_entry_lba = cpu_to_le64(partition_entries_offset(dev_desc));

        gpt_h->header_crc32 = 0;

        calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
                               le32_to_cpu(gpt_h->header_size));
        gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
}

static int write_one_gpt_table(struct blk_desc *dev_desc,
                               gpt_header *gpt_h, gpt_entry *gpt_e)
{
        const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
                                           * sizeof(gpt_entry)), dev_desc);
        lbaint_t start;
        int ret = 0;

        start = le64_to_cpu(gpt_h->my_lba);
        if (blk_dwrite(dev_desc, start, 1, gpt_h) != 1) {
                ret = -1;
                goto out;
        }

        start = le64_to_cpu(gpt_h->partition_entry_lba);
        if (blk_dwrite(dev_desc, start, pte_blk_cnt, gpt_e) != pte_blk_cnt) {
                ret = -1;
                goto out;
        }

 out:
        return ret;
}

int gpt_repair_headers(struct blk_desc *dev_desc)
{
        ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_h1, 1, dev_desc->blksz);
        ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_h2, 1, dev_desc->blksz);
        gpt_entry *gpt_e1 = NULL, *gpt_e2 = NULL;
        int is_gpt1_valid, is_gpt2_valid;
        int ret = -1;

        is_gpt1_valid = is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
                                     gpt_h1, &gpt_e1);
        is_gpt2_valid = is_gpt_valid(dev_desc, dev_desc->lba - 1,
                                     gpt_h2, &gpt_e2);

        if (is_gpt1_valid && is_gpt2_valid) {
                ret = 0;
                goto out;
        }

        if (is_gpt1_valid && !is_gpt2_valid) {
                prepare_backup_gpt_header(gpt_h1);
                ret = write_one_gpt_table(dev_desc, gpt_h1, gpt_e1);
                goto out;
        }

        if (!is_gpt1_valid && is_gpt2_valid) {
                restore_primary_gpt_header(gpt_h2, dev_desc);
                ret = write_one_gpt_table(dev_desc, gpt_h2, gpt_e2);
                goto out;
        }

        if (!is_gpt1_valid && !is_gpt2_valid) {
                ret = -1;
                goto out;
        }

 out:
        if (is_gpt1_valid)
                free(gpt_e1);
        if (is_gpt2_valid)
                free(gpt_e2);

        return ret;
}

int gpt_verify_partitions(struct blk_desc *dev_desc,
                          struct disk_partition *partitions, int parts,
                          gpt_header *gpt_head, gpt_entry **gpt_pte)
{
        char efi_str[PARTNAME_SZ + 1];
        u64 gpt_part_size;
        gpt_entry *gpt_e;
        int ret, i;

        ret = gpt_verify_headers(dev_desc, gpt_head, gpt_pte);
        if (ret)
                return ret;

        gpt_e = *gpt_pte;

        for (i = 0; i < parts; i++) {
                if (i == gpt_head->num_partition_entries) {
                        pr_err("More partitions than allowed!\n");
                        return -1;
                }

                /* Check if GPT and ENV partition names match */
                gpt_convert_efi_name_to_char(efi_str, gpt_e[i].partition_name,
                                             PARTNAME_SZ + 1);

                debug("%s: part: %2d name - GPT: %16s, ENV: %16s ",
                      __func__, i, efi_str, partitions[i].name);

                if (strncmp(efi_str, (char *)partitions[i].name,
                            sizeof(partitions->name))) {
                        pr_err("Partition name: %s does not match %s!\n",
                              efi_str, (char *)partitions[i].name);
                        return -1;
                }

                /* Check if GPT and ENV sizes match */
                gpt_part_size = le64_to_cpu(gpt_e[i].ending_lba) -
                        le64_to_cpu(gpt_e[i].starting_lba) + 1;
                debug("size(LBA) - GPT: %8llu, ENV: %8llu ",
                      (unsigned long long)gpt_part_size,
                      (unsigned long long)partitions[i].size);

                if (le64_to_cpu(gpt_part_size) != partitions[i].size) {
                        /* We do not check the extend partition size */
                        if ((i == parts - 1) && (partitions[i].size == 0))
                                continue;

                        pr_err("Partition %s size: %llu does not match %llu!\n",
                              efi_str, (unsigned long long)gpt_part_size,
                              (unsigned long long)partitions[i].size);
                        return -1;
                }

                /*
                 * Start address is optional - check only if provided
                 * in '$partition' variable
                 */
                if (!partitions[i].start) {
                        debug("\n");
                        continue;
                }

                /* Check if GPT and ENV start LBAs match */
                debug("start LBA - GPT: %8llu, ENV: %8llu\n",
                      le64_to_cpu(gpt_e[i].starting_lba),
                      (unsigned long long)partitions[i].start);

                if (le64_to_cpu(gpt_e[i].starting_lba) != partitions[i].start) {
                        pr_err("Partition %s start: %llu does not match %llu!\n",
                              efi_str, le64_to_cpu(gpt_e[i].starting_lba),
                              (unsigned long long)partitions[i].start);
                        return -1;
                }
        }

        return 0;
}

int is_valid_gpt_buf(struct blk_desc *dev_desc, void *buf)
{
        gpt_header *gpt_h;
        gpt_entry *gpt_e;

        /* determine start of GPT Header in the buffer */
        gpt_h = buf + (GPT_PRIMARY_PARTITION_TABLE_LBA *
                       dev_desc->blksz);
        if (validate_gpt_header(gpt_h, GPT_PRIMARY_PARTITION_TABLE_LBA,
                                dev_desc->lba))
                return -1;

        /* determine start of GPT Entries in the buffer */
        gpt_e = buf + (le64_to_cpu(gpt_h->partition_entry_lba) *
                       dev_desc->blksz);
        if (validate_gpt_entries(gpt_h, gpt_e))
                return -1;

        return 0;
}

int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
{
        gpt_header *gpt_h;
        gpt_entry *gpt_e;
        int gpt_e_blk_cnt;
        lbaint_t lba;
        int cnt;

        if (is_valid_gpt_buf(dev_desc, buf))
                return -1;

        /* determine start of GPT Header in the buffer */
        gpt_h = buf + (GPT_PRIMARY_PARTITION_TABLE_LBA *
                       dev_desc->blksz);

        /* determine start of GPT Entries in the buffer */
        gpt_e = buf + (le64_to_cpu(gpt_h->partition_entry_lba) *
                       dev_desc->blksz);
        gpt_e_blk_cnt = BLOCK_CNT((le32_to_cpu(gpt_h->num_partition_entries) *
                                   le32_to_cpu(gpt_h->sizeof_partition_entry)),
                                  dev_desc);

        /* write MBR */
        lba = 0;        /* MBR is always at 0 */
        cnt = 1;        /* MBR (1 block) */
        if (blk_dwrite(dev_desc, lba, cnt, buf) != cnt) {
                log_debug("failed writing '%s' (%d blks at 0x" LBAF ")\n",
                          "MBR", cnt, lba);
                return 1;
        }

        /* write Primary GPT */
        lba = GPT_PRIMARY_PARTITION_TABLE_LBA;
        cnt = 1;        /* GPT Header (1 block) */
        if (blk_dwrite(dev_desc, lba, cnt, gpt_h) != cnt) {
                log_debug("failed writing '%s' (%d blks at 0x" LBAF ")\n",
                          "Primary GPT Header", cnt, lba);
                return 1;
        }

        lba = le64_to_cpu(gpt_h->partition_entry_lba);
        cnt = gpt_e_blk_cnt;
        if (blk_dwrite(dev_desc, lba, cnt, gpt_e) != cnt) {
                log_debug("failed writing '%s' (%d blks at 0x" LBAF ")\n",
                          "Primary GPT Entries", cnt, lba);
                return 1;
        }

        prepare_backup_gpt_header(gpt_h);

        /* write Backup GPT */
        lba = le64_to_cpu(gpt_h->partition_entry_lba);
        cnt = gpt_e_blk_cnt;
        if (blk_dwrite(dev_desc, lba, cnt, gpt_e) != cnt) {
                log_debug("failed writing '%s' (%d blks at 0x" LBAF ")\n",
                          "Backup GPT Entries", cnt, lba);
                return 1;
        }

        lba = le64_to_cpu(gpt_h->my_lba);
        cnt = 1;        /* GPT Header (1 block) */
        if (blk_dwrite(dev_desc, lba, cnt, gpt_h) != cnt) {
                log_debug("failed writing '%s' (%d blks at 0x" LBAF ")\n",
                          "Backup GPT Header", cnt, lba);
                return 1;
        }

        /* Update the partition table entries*/
        part_init(dev_desc);

        return 0;
}
#endif

/*
 * Private functions
 */
/*
 * pmbr_part_valid(): Check for EFI partition signature
 *
 * Returns: 1 if EFI GPT partition type is found.
 */
static int pmbr_part_valid(struct partition *part)
{
        if (part->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT &&
                get_unaligned_le32(&part->start_sect) == 1UL) {
                return 1;
        }

        return 0;
}

/*
 * is_pmbr_valid(): test Protective MBR for validity
 *
 * Returns: 1 if PMBR is valid, 0 otherwise.
 * Validity depends on two things:
 *  1) MSDOS signature is in the last two bytes of the MBR
 *  2) One partition of type 0xEE is found, checked by pmbr_part_valid()
 */
static int is_pmbr_valid(legacy_mbr * mbr)
{
        int i = 0;

        if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
                return 0;

        for (i = 0; i < 4; i++) {
                if (pmbr_part_valid(&mbr->partition_record[i])) {
                        return 1;
                }
        }
        return 0;
}

/**
 * is_gpt_valid() - tests one GPT header and PTEs for validity
 *
 * lba is the logical block address of the GPT header to test
 * gpt is a GPT header ptr, filled on return.
 * ptes is a PTEs ptr, filled on return.
 *
 * Description: returns 1 if valid,  0 on error, 2 if ignored header
 * If valid, returns pointers to PTEs.
 */
static int is_gpt_valid(struct blk_desc *dev_desc, u64 lba,
                        gpt_header *pgpt_head, gpt_entry **pgpt_pte)
{
        /* Confirm valid arguments prior to allocation. */
        if (!dev_desc || !pgpt_head) {
                log_debug("Invalid Argument(s)\n");
                return 0;
        }

        ALLOC_CACHE_ALIGN_BUFFER_PAD(legacy_mbr, mbr, 1, dev_desc->blksz);

        /* Read MBR Header from device */
        if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1) {
                log_debug("Can't read MBR header\n");
                return 0;
        }

        /* Read GPT Header from device */
        if (blk_dread(dev_desc, (lbaint_t)lba, 1, pgpt_head) != 1) {
                log_debug("Can't read GPT header\n");
                return 0;
        }

        /* Invalid but nothing to yell about. */
        if (le64_to_cpu(pgpt_head->signature) == GPT_HEADER_CHROMEOS_IGNORE) {
                log_debug("ChromeOS 'IGNOREME' GPT header found and ignored\n");
                return 2;
        }

        if (validate_gpt_header(pgpt_head, (lbaint_t)lba, dev_desc->lba))
                return 0;

        if (dev_desc->sig_type == SIG_TYPE_NONE) {
                efi_guid_t empty = {};
                if (memcmp(&pgpt_head->disk_guid, &empty, sizeof(empty))) {
                        dev_desc->sig_type = SIG_TYPE_GUID;
                        memcpy(&dev_desc->guid_sig, &pgpt_head->disk_guid,
                              sizeof(empty));
                } else if (mbr->unique_mbr_signature != 0) {
                        dev_desc->sig_type = SIG_TYPE_MBR;
                        dev_desc->mbr_sig = mbr->unique_mbr_signature;
                }
        }

        /* Read and allocate Partition Table Entries */
        *pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
        if (!*pgpt_pte)
                return 0;

        if (validate_gpt_entries(pgpt_head, *pgpt_pte)) {
                free(*pgpt_pte);
                return 0;
        }

        /* We're done, all's well */
        return 1;
}

/**
 * find_valid_gpt() - finds a valid GPT header and PTEs
 *
 * gpt is a GPT header ptr, filled on return.
 * ptes is a PTEs ptr, filled on return.
 *
 * Description: returns 1 if found a valid gpt,  0 on error.
 * If valid, returns pointers to PTEs.
 */
static int find_valid_gpt(struct blk_desc *dev_desc, gpt_header *gpt_head,
                          gpt_entry **pgpt_pte)
{
        int r;

        r = is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA, gpt_head,
                         pgpt_pte);

        if (r != 1) {
                if (r != 2)
                        log_debug("Invalid GPT\n");

                if (is_gpt_valid(dev_desc, (dev_desc->lba - 1), gpt_head,
                                 pgpt_pte) != 1) {
                        log_debug("Invalid Backup GPT\n");
                        return 0;
                }
                if (r != 2)
                        log_debug("        Using Backup GPT\n");
        }
        return 1;
}

/**
 * alloc_read_gpt_entries(): reads partition entries from disk
 * @dev_desc
 * @gpt - GPT header
 *
 * Description: Returns ptes on success,  NULL on error.
 * Allocates space for PTEs based on information found in @gpt.
 * Notes: remember to free pte when you're done!
 */
static gpt_entry *alloc_read_gpt_entries(struct blk_desc *dev_desc,
                                         gpt_header *pgpt_head)
{
        size_t count = 0, blk_cnt;
        lbaint_t blk;
        gpt_entry *pte = NULL;

        if (!dev_desc || !pgpt_head) {
                log_debug("Invalid Argument(s)\n");
                return NULL;
        }

        count = le32_to_cpu(pgpt_head->num_partition_entries) *
                le32_to_cpu(pgpt_head->sizeof_partition_entry);

        log_debug("count = %u * %u = %lu\n",
                  (u32)le32_to_cpu(pgpt_head->num_partition_entries),
                  (u32)le32_to_cpu(pgpt_head->sizeof_partition_entry),
                  (ulong)count);

        /* Allocate memory for PTE, remember to FREE */
        if (count != 0) {
                pte = memalign(ARCH_DMA_MINALIGN,
                               PAD_TO_BLOCKSIZE(count, dev_desc));
        }

        if (count == 0 || pte == NULL) {
                log_debug("ERROR: Can't allocate %#lX bytes for GPT Entries\n",
                          (ulong)count);
                return NULL;
        }

        /* Read GPT Entries from device */
        blk = le64_to_cpu(pgpt_head->partition_entry_lba);
        blk_cnt = BLOCK_CNT(count, dev_desc);
        if (blk_dread(dev_desc, blk, (lbaint_t)blk_cnt, pte) != blk_cnt) {
                log_debug("Can't read GPT Entries\n");
                free(pte);
                return NULL;
        }
        return pte;
}

/**
 * is_pte_valid(): validates a single Partition Table Entry
 * @gpt_entry - Pointer to a single Partition Table Entry
 *
 * Description: returns 1 if valid,  0 on error.
 */
static int is_pte_valid(gpt_entry * pte)
{
        efi_guid_t unused_guid;

        if (!pte) {
                log_debug("Invalid Argument(s)\n");
                return 0;
        }

        /* Only one validation for now:
         * The GUID Partition Type != Unused Entry (ALL-ZERO)
         */
        memset(unused_guid.b, 0, sizeof(unused_guid.b));

        if (memcmp(pte->partition_type_guid.b, unused_guid.b,
                sizeof(unused_guid.b)) == 0) {

                log_debug("Found an unused PTE GUID at 0x%08X\n",
                          (unsigned int)(uintptr_t)pte);

                return 0;
        } else {
                return 1;
        }
}

/*
 * Add an 'a_' prefix so it comes before 'dos' in the linker list. We need to
 * check EFI first, since a DOS partition is often used as a 'protective MBR'
 * with EFI.
 */
U_BOOT_PART_TYPE(a_efi) = {
        .name           = "EFI",
        .part_type      = PART_TYPE_EFI,
        .max_entries    = GPT_ENTRY_NUMBERS,
        .get_info       = part_get_info_ptr(part_get_info_efi),
        .print          = part_print_ptr(part_print_efi),
        .test           = part_test_efi,
};