On Wed, Apr 01, 2020 at 04:04:04PM +0900, AKASHI Takahiro wrote:
[...]
Yes, we may add further stores later on.
Why not now? How will you generalize it?
Ilias wants to use the RPMB area of eMMC devices.
I think that he plans to use RPMB as secure storage for Standalone MM.
Sorry for my really delayed replies, but I was over my head with EDK2 and RPMB indeed :) So my implementation is orthogonal to this patchset and I do have some code that write UEFI variables on an RPMB via OP-TEE.
As an EFI system partition exists on any UEFI compatible device I think implementing this first is a valid approach.
I don't deny your approach here, but I expect that more generic framework for back storage be implemented and FAT driver be on top of that.
Akashi has a point here. On the other hand can't we just make the store a callback in the future? So for example is FAT_FS support is not included, we write the data into raw flash sectors or a file. That being said EDK2 uses Fvb and Fault Tolerant Writes to write the actual UEFI variables. So you end up needing 3 partitions for the actual storage. The question here is should we implement something similar to u-boot EFI code since this is only supposed to serve as a 'fallback'? If the board has OP-TEE then that will be responsible for writing the variables (and it will use whatever EDK2 uses).
I'll have a closer look to the patchset and try to give some feedback.
Regards /Ilias
-Takahiro Akashi
Best regards
Heinrich
-Takahiro Akashi
-Takahiro Akashi
Best regards
Heinrich
>> >> In addition, why do you treat FAT specifically here? >> I remember that you insisted that other file system should be >> allowed on U-Boot when I posted some patch. > > An EFI system partition is always FAT formatted. So if we want to safe > U-Boot variables to the EFI system partition we require FAT.
As system partition is required to be in FAT, file system used on other partitions must also be in FAT since, as I said before, UEFI specification clearly defines its file system format based on FAT. See section 13.3.
So,
>> I remember that you insisted that other file system should be >> allowed on U-Boot when I posted some patch.
You reverted your statement above here. That is my point.
-Takahiro Akashi
> Best regards > > Heinrich > >> >> -Takahiro Akashi >> >> >>> imply USB_KEYBOARD_FN_KEYS >>> imply VIDEO_ANSI >>> help >>> -- >>> 2.25.1