[coreboot] SELF/ELF/LAR

Jordan Crouse jordan.crouse at amd.com
Wed Apr 16 19:53:34 CEST 2008

On 16/04/08 11:36 -0600, Myles Watson wrote:
> > I totaly agree - and SELF reflects that behavior without the additional
> > LAR segments.  I'm not even sure if Segher is promoting just tossing it
> > into the LAR without parsing, but I don't want to put words in his mouth.
> > 
> Here's my opinion based on the discussion so far:
> I like the idea of SELF except as a file format.  I think SELF should stay
> internal to LAR.  With the information in SELF we can create a valid ELF
> file at extraction time.  That way we only have one way to get a Payload
> into LAR (parsing an ELF) and one way out.  Coreboot code only needs to know
> about the SELF format, and we have many fewer code paths to test and
> maintain.

Yes, SELF was always intended to be internal to LAR.  To be completely
honest with you, I don't really see much value in extracting a LAR.  LAR
may have started as an archiver format, but it has long since lost 
nearly all those characteristics.  I realize why extraction may exist -
if I am handed an ambiguous blob from an unknown source, I may want to
be able to pull out the individual parts, but my only concern is being
able to do things correctly during boot.

So we'll make that rule for SELF - it will always been an internal format.
it will never exist outside of the LAR. If we extract the file, then we'll
construct an ELF from the internal format.

> My fear was that LAR was going to need to parse ELF and SELF, and so was
> Coreboot.  I think at least one of those pathways would bit rot quickly.

Yes - and that would also require us to have some SELF tools available in
the toolchain - not an interesting prospect for us.


Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.

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