Re: [RFC PATCH 0/1] Add driver for bootstage stash

Hi Federico,

On Friday, 23 May 2025 at 09:34:09 Federico Giovanardi <[email protected]> wrote:
> Hello,
> 
> The note about the data format also was my initial thought, by just 
> copying a C structure we might have issues as soon one party changes it, 
> and they might not be perfectly aligned.
> 

Definitely - before a proper implementation, a formal specification with
a versioning should probably be defined.

> To avoid inventing yet-another-data-format I've used msgpack in the past 
> for that (the format 
> https://github.com/msgpack/msgpack/blob/master/spec.md, not the library  
> ); because the specs are so simple they can be implemented in a few 
> lines, and it's something with a reference. But I don't have a lot of 
> experience in upstreaming stuff on the kernel, so I don't know if it 
> might cause someone to don't be happy. Anyway, I can contribute the 
> implementation if needed.
> 

I'd avoid a serialization technology here, as it would be another
(somewhat costly) step before booting, while re-using the memory area
that the bootloader itself uses as stash is basically free.


Regards,
Francesco