[PATCH v3 2/2] efi_loader: identify EFI system partition

[Heinrich Schuchardt]

On 4/23/20 2:19 AM, AKASHI Takahiro wrote:
> Heinrich,
>
> On Wed, Apr 22, 2020 at 07:51:33PM +0200, Heinrich Schuchardt wrote:
>> In subsequent patches UEFI variables shalled be stored on the EFI system
>> partition. Hence we need to identify the EFI system partition.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>> v3:
>> 	adjust commit message
>
>
> I said 'no' along with my counter proposals[1], and you haven't
> replied yet.
>
> [1] https://lists.denx.de/pipermail/u-boot/2020-April/406678.html

For some scenarios it may make sense to be able to specify a boot device
containing variables via a Kconfig option. This patch does not stop us
for implementing this.

If you take a Linux distribution that can either be installed on eMMC or
on an SD-card of the same board, autodetection of the EFI system
partition may be a more a better choice than providing multiple U-Boot
builds.

Both approaches have there merits and both could be enabled via Kconfig.

Best regards

Heinrich

>
> -Takahiro Akashi
>
>> 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 0ba9a1f702..b7bccf50b3 100644
>> --- a/include/efi_loader.h
>> +++ b/include/efi_loader.h
>> @@ -47,6 +47,13 @@ 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 fd8fe17567..fd3df80b0b 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;
>>
>>  /**
>> @@ -418,6 +420,24 @@ 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;
>>  }
>>
>> --
>> 2.26.1
>>