[PATCH v2 1/2] part: detect EFI system partition

[Heinrich Schuchardt]

Up to now for MBR and GPT partitions the info field 'bootable' was set to 1
if either the partition was an EFI system partition or the bootable flag
was set.

Turn info field 'bootable' into a bit mask with separate bits for bootable
and EFI system partition.

This will allow us to identify the EFI system partition in the UEFI
sub-system.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
v2:
	used BIT() macro to define bit mask
---
 disk/part_dos.c | 10 ++++++++--
 disk/part_efi.c | 12 ++++++++----
 include/part.h  | 11 ++++++++++-
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 83ff40d310..0ec7f1628e 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -45,9 +45,15 @@ static inline int is_extended(int part_type)
 	    part_type == 0x85);
 }

-static inline int is_bootable(dos_partition_t *p)
+static int is_bootable(dos_partition_t *p)
 {
-	return (p->sys_ind == 0xef) || (p->boot_ind == 0x80);
+	int ret = 0;
+
+	if (p->sys_ind == 0xef)
+		ret |= PART_EFI_SYSTEM_PARTITION;
+	if (p->boot_ind == 0x80)
+		ret |= PART_BOOTABLE;
+	return ret;
 }

 static void print_one_part(dos_partition_t *p, lbaint_t ext_part_sector,
diff --git a/disk/part_efi.c b/disk/part_efi.c
index b2e157d9c1..19f1f43f4e 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -71,11 +71,15 @@ static char *print_efiname(gpt_entry *pte)

 static const efi_guid_t system_guid = PARTITION_SYSTEM_GUID;

-static inline int is_bootable(gpt_entry *p)
+static int is_bootable(gpt_entry *p)
 {
-	return p->attributes.fields.legacy_bios_bootable ||
-		!memcmp(&(p->partition_type_guid), &system_guid,
-			sizeof(efi_guid_t));
+	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,
diff --git a/include/part.h b/include/part.h
index 0b5cf3d5e8..f3442ef85d 100644
--- a/include/part.h
+++ b/include/part.h
@@ -51,13 +51,22 @@ struct block_drvr {
 #define PART_TYPE_LEN 32
 #define MAX_SEARCH_PARTITIONS 64

+#define PART_BOOTABLE			BIT(0)
+#define PART_EFI_SYSTEM_PARTITION	BIT(1)
+
 typedef struct disk_partition {
 	lbaint_t	start;	/* # of first block in partition	*/
 	lbaint_t	size;	/* number of blocks in partition	*/
 	ulong	blksz;		/* block size in bytes			*/
 	uchar	name[PART_NAME_LEN];	/* partition name			*/
 	uchar	type[PART_TYPE_LEN];	/* string type description		*/
-	int	bootable;	/* Active/Bootable flag is set		*/
+	/*
+	 * The bootable is a bitmask with the following fields:
+	 *
+	 * PART_BOOTABLE		the MBR bootable flag is set
+	 * PART_EFI_SYSTEM_PARTITION	the partition is an EFI system partition
+	 */
+	int	bootable;
 #if CONFIG_IS_ENABLED(PARTITION_UUIDS)
 	char	uuid[UUID_STR_LEN + 1];	/* filesystem UUID as string, if exists	*/
 #endif
--
2.25.1