[coreboot] SELF/ELF/LAR

Myles Watson mylesgw at gmail.com
Wed Apr 16 19:59:44 CEST 2008

> -----Original Message-----
> From: Jordan Crouse [mailto:jordan.crouse at amd.com]
> Sent: Wednesday, April 16, 2008 11:54 AM
> To: Myles Watson
> Cc: coreboot at coreboot.org
> Subject: Re: SELF/ELF/LAR
> 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.

I think another interesting case is when something broke and you want to
isolate it.  It would be interesting to pull just the payload from a working
ROM to try in a broken one or vice versa.

> 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.

All right! At least two people agree on something!

Thanks for your patience in explaining and iterating with me.


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