[PATCH v2 2/2] efi_loader: identify EFI system partition

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

Heinrich,

On Sun, Apr 05, 2020 at 11:28:18AM +0200, Heinrich Schuchardt wrote:
> For capsule updates we need to identify the EFI system partition.

Right, but

> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ---
> v2:
> 	no change
> ---
>  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 3f2792892f..4a45033476 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 */

I don't think that the policy, first comes first serves as system
partition, is a right decision as
- the order of device probe on U-Boot is indeterministic, and
- there can be several partitions that hold a system partition bit.
  You may have OS installed on eMMC, but also may have bootable DVD
  on the system.

-Takahiro Akashi

> +	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;
>  }
> 
> --
> 2.25.1
>