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: Steve Rae <s...@broadcom.com>
---
Changes in v3:
- renamed: "Secondary GPT" to "Backup GPT"
Changes in v2:
- changed wording: "Alternate" to "Secondary"
disk/part_efi.c | 22 +++++++++++++++++++---
doc/README.gpt | 14 +++++++-------
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/disk/part_efi.c b/disk/part_efi.c
index 216a292..c74b7b9 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -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);
diff --git a/doc/README.gpt b/doc/README.gpt
index f822894..ec0156d 100644
--- a/doc/README.gpt
+++ b/doc/README.gpt
@@ -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:
--
1.8.5
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