[coreboot] SELF/ELF/LAR

Patrick Georgi patrick at georgi-clan.de
Wed Apr 16 18:16:16 CEST 2008

Am Mittwoch, den 16.04.2008, 10:02 -0600 schrieb Myles Watson:
> I like the current ability to compress payload segments based on the
> best
> compression for that segment.  It seems like we lose that if we put ELF
> files (or a simple alternative) into the LAR without parsing them.
The only reason for that so far was a replacement for the BSS section,
which exists in ELF.

How about teaching LAR to have chunks, like:
  LAR header (file is 40000 bytes compressed, 160000 uncomp., 3 chunks)
  chunk header 1 (200 bytes, compression type 1)
   data (eg. ELF headers)
  chunk header 2 (39000 bytes, compression type 2)
   more data (most sections in ELF)
  chunk header 3 (800 bytes, compression type 3)
   some more data

chunk headers could be written only if there's more than one chunk,
making this backward compatible.

It would be the duty of lar (the tool) to make sense of an ELF file to
define a sensible chunk layout for it.

With our hypothetical manifest file for LAR file handling, that could
even be saved (and created by third party tools, for other formats), but
the important property of this is that extracting and readding the file
doesn't kill important data (eg. load and entry points), while there's
still a 1:1 relation between payload and files in lar, but more


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