[PATCH 0/2] efi_loader: detect EFI system partition

[PATCH 0/2] efi_loader: detect EFI system partition

[Heinrich Schuchardt]

For the implementation of capsule updates we need to know where the EFI
system partition is located.

With the patches the first available EFI system partition is determined
both for MBR and GPT partition tables.

Heinrich Schuchardt (2):
  part: detect EFI system partition
  efi_loader: identify EFI system partition

 disk/part_dos.c           | 10 ++++++++--
 disk/part_efi.c           | 12 ++++++++----
 include/efi_loader.h      |  7 +++++++
 include/part.h            | 11 ++++++++++-
 lib/efi_loader/efi_disk.c | 20 ++++++++++++++++++++
 5 files changed, 53 insertions(+), 7 deletions(-)

--
2.20.1

[PATCH 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@gmx.de>
---
 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..a63d1d0cda 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			1
+#define PART_EFI_SYSTEM_PARTITION	2
+
 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
--
2.20.1

[PATCH 2/2] efi_loader: identify EFI system partition

[Heinrich Schuchardt]

For capsule updates we need to identify the EFI system partition.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 include/efi_loader.h      |  7 +++++++
 lib/efi_loader/efi_disk.c | 20 ++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 37c3f15da1..536ef84cb5 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -45,6 +45,13 @@ static inline void *guidcpy(void *dst, const void *src)
 /* Root node */
 extern efi_handle_t efi_root;

+/* EFI system partition */
+extern struct efi_system_partition {
+	enum if_type if_type;
+	int devnum;
+	u8 part;
+} efi_system_partition;
+
 int __efi_entry_check(void);
 int __efi_exit_check(void);
 const char *__efi_nesting(void);
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index fc0682bc48..2f752a5e99 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -13,6 +13,8 @@
 #include <part.h>
 #include <malloc.h>

+struct efi_system_partition efi_system_partition;
+
 const efi_guid_t efi_block_io_guid = EFI_BLOCK_IO_PROTOCOL_GUID;

 /**
@@ -372,6 +374,24 @@ static efi_status_t efi_disk_add_dev(
 	diskobj->ops.media = &diskobj->media;
 	if (disk)
 		*disk = diskobj;
+
+	/* Store first EFI system partition */
+	if (part && !efi_system_partition.if_type) {
+		int r;
+		disk_partition_t info;
+
+		r = part_get_info(desc, part, &info);
+		if (r)
+			return EFI_DEVICE_ERROR;
+		if (info.bootable & PART_EFI_SYSTEM_PARTITION) {
+			efi_system_partition.if_type = desc->if_type;
+			efi_system_partition.devnum = desc->devnum;
+			efi_system_partition.part = part;
+			EFI_PRINT("EFI system partition: %s %d:%d\n",
+				  blk_get_if_type_name(desc->if_type),
+				  desc->devnum, part);
+		}
+	}
 	return EFI_SUCCESS;
 }

--
2.20.1

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

[Punit Agrawal]

Hi Heinrich,

Heinrich Schuchardt <xypron.glpk@gmx.de> writes:

> 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@gmx.de>
> ---
>  disk/part_dos.c | 10 ++++++++--
>  disk/part_efi.c | 12 ++++++++----
>  include/part.h  | 11 ++++++++++-
>  3 files changed, 26 insertions(+), 7 deletions(-)
>

[...]

> diff --git a/include/part.h b/include/part.h
> index 0b5cf3d5e8..a63d1d0cda 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			1
> +#define PART_EFI_SYSTEM_PARTITION	2

As these defines are used as flags, it be better to use the BIT() macro
to make it explicit that these are bit positions rather than sequential
values.

Thanks,
Punit


> +
>  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
> --
> 2.20.1