Commit ae95fad5 authored by Steve Rae's avatar Steve Rae Committed by Tom Rini

disk: part_efi: add support for the Backup GPT

Check the Backup GPT table if the Primary GPT table is invalid.
Renamed "Secondary GPT" to "Backup GPT" as per:
  UEFI Specification (Version 2.3.1, Errata A)
Signed-off-by: default avatarSteve Rae <srae@broadcom.com>
parent fa39ffe5
......@@ -93,7 +93,15 @@ void print_part_efi(block_dev_desc_t * dev_desc)
if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
return;
if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid Backup GPT ***\n",
__func__);
return;
} else {
printf("%s: *** Using Backup GPT ***\n",
__func__);
}
}
debug("%s: gpt-entry at %p\n", __func__, gpt_pte);
......@@ -142,7 +150,15 @@ int get_partition_info_efi(block_dev_desc_t * dev_desc, int part,
if (is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid GPT ***\n", __func__);
return -1;
if (is_gpt_valid(dev_desc, (dev_desc->lba - 1),
gpt_head, &gpt_pte) != 1) {
printf("%s: *** ERROR: Invalid Backup GPT ***\n",
__func__);
return -1;
} else {
printf("%s: *** Using Backup GPT ***\n",
__func__);
}
}
if (part > le32_to_cpu(gpt_head->num_partition_entries) ||
......@@ -252,7 +268,7 @@ int write_gpt_table(block_dev_desc_t *dev_desc,
!= pte_blk_cnt)
goto err;
/* recalculate the values for the Second GPT Header */
/* 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);
......
......@@ -66,14 +66,14 @@ GPT brief explanation:
|Partition n |
| |
----------------------------------------------------------
LBA -34 |Entry 1|Entry 2| Entry 3| Entry 4| Secondary
-------------------------------------------------- (bkp)
LBA -33 |Entries 5 - 128 | GPT
LBA -34 |Entry 1|Entry 2| Entry 3| Entry 4| Backup
-------------------------------------------------- GPT
LBA -33 |Entries 5 - 128 |
| |
| |
LBA -2 | |
--------------------------------------------------
LBA -1 |Secondary GPT Header |
LBA -1 |Backup GPT Header |
----------------------------------------------------------
For a legacy reasons, GPT's LBA 0 sector has a MBR structure. It is called
......@@ -86,7 +86,7 @@ It is possible to define 128 linearly placed partition entries.
"LBA -1" means the last addressable block (in the mmc subsystem:
"dev_desc->lba - 1")
Primary/Secondary GPT header:
Primary/Backup GPT header:
----------------------------
Offset Size Description
......@@ -115,7 +115,7 @@ IMPORTANT:
GPT headers and partition entries are protected by CRC32 (the POSIX CRC32).
Primary GPT header and Secondary GPT header have swapped values of "Current LBA"
Primary GPT header and Backup GPT header have swapped values of "Current LBA"
and "Backup LBA" and therefore different CRC32 check-sum.
CRC32 for GPT headers (field "CRC of header") are calculated up till
......@@ -125,7 +125,7 @@ CRC32 for partition entries (field "CRC32 of partition array") is calculated for
the whole array entry ( Number_of_partition_entries *
sizeof(partition_entry_size (usually 128)))
Observe, how Secondary GPT is placed in the memory. It is NOT a mirror reflect
Observe, how Backup GPT is placed in the memory. It is NOT a mirror reflect
of the Primary.
Partition Entry Format:
......
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