[U-Boot] [PATCH v2 02/21] part: extract MBR signature from partitions

Rob Clark
2017-09-10T11:21:21Z

From: Peter Jones <pjones@redhat.com>

EFI client programs need the signature information from the partition
table to determine the disk a partition is on, so we need to fill that
in here.

Signed-off-by: Peter Jones <pjones@redhat.com>
[separated from efi_loader part, and fixed build-errors for non-
CONFIG_EFI_PARTITION case]
Signed-off-by: Rob Clark <robdclark@gmail.com>
---
disk/part_dos.c | 12 +++++++++---
disk/part_efi.c | 20 ++++++++++++++++++++
include/blk.h | 15 +++++++++++++++
3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 7ede15ec26..850a538e83 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -89,14 +89,20 @@ static int test_block_type(unsigned char *buffer)

static int part_test_dos(struct blk_desc *dev_desc)
{
- ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
+ ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, dev_desc->blksz);

- if (blk_dread(dev_desc, 0, 1, (ulong *)buffer) != 1)
+ if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1)
return -1;

- if (test_block_type(buffer) != DOS_MBR)
+ if (test_block_type((unsigned char *)mbr) != DOS_MBR)
return -1;

+ if (dev_desc->sig_type == SIG_TYPE_NONE &&
+ mbr->unique_mbr_signature != 0) {
+ dev_desc->sig_type = SIG_TYPE_MBR;
+ dev_desc->mbr_sig = mbr->unique_mbr_signature;
+ }
+
return 0;
}

diff --git a/disk/part_efi.c b/disk/part_efi.c
index 2973d52f6a..208bb14ee8 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -923,11 +923,19 @@ 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)
{
+ ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, dev_desc->blksz);
+
if (!dev_desc || !pgpt_head) {
printf("%s: Invalid Argument(s)\n", __func__);
return 0;
}

+ /* Read MBR Header from device */
+ if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1) {
+ printf("*** ERROR: 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) {
printf("*** ERROR: Can't read GPT header ***\n");
@@ -937,6 +945,18 @@ static int is_gpt_valid(struct blk_desc *dev_desc, u64 lba,
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 == NULL) {
diff --git a/include/blk.h b/include/blk.h
index a106f9ca0e..3c59fdb3d4 100644
--- a/include/blk.h
+++ b/include/blk.h
@@ -8,6 +8,8 @@
#ifndef BLK_H
#define BLK_H

+#include <efi.h>
+
#ifdef CONFIG_SYS_64BIT_LBA
typedef uint64_t lbaint_t;
#define LBAFlength "ll"
@@ -36,6 +38,14 @@ enum if_type {
IF_TYPE_COUNT, /* Number of interface types */
};

+enum sig_type {
+ SIG_TYPE_NONE,
+ SIG_TYPE_MBR,
+ SIG_TYPE_GUID,
+
+ SIG_TYPE_COUNT /* Number of signature types */
+};
+
/*
* With driver model (CONFIG_BLK) this is uclass platform data, accessible
* with dev_get_uclass_platdata(dev)
@@ -63,6 +73,11 @@ struct blk_desc {
char vendor[40+1]; /* IDE model, SCSI Vendor */
char product[20+1]; /* IDE Serial no, SCSI product */
char revision[8+1]; /* firmware revision */
+ enum sig_type sig_type; /* Partition table signature type */
+ union {
+ uint32_t mbr_sig; /* MBR integer signature */
+ efi_guid_t guid_sig; /* GPT GUID Signature */
+ };
#if CONFIG_IS_ENABLED(BLK)
/*
* For now we have a few functions which take struct blk_desc as a
--
2.13.5