commit ae95fad5af3793ae804b4390727e0f431e5514d7
author Steve Rae <srae@broadcom.com> Mon May 05 13:00:08 2014 -0700
committer Tom Rini <trini@ti.com> Mon May 12 15:20:05 2014 -0400
tree 65de51deeb3eef975b9f593f1cb9f36c1d3a1dbb
parent fa39ffe5d61bd7f34b2ff579f5f6bb8f92a6b9b1

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: Steve Rae <srae@broadcom.com>

disk/part_efi.c

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 @@
 	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 @@
 	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 @@
 	    != 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);