[U-Boot-Users] Changing u-boot relocation scheme

Kenneth Johansson kenneth at southpole.se
Thu Jul 24 15:17:38 CEST 2008


On Thu, 2008-07-24 at 15:01 +0200, Wolfgang Denk wrote:
> In message <f608b67d0807232345r482792b6lbc9bd6804f48e597 at mail.gmail.com> you wrote:
> > Quite frankly, GOT is also clumsy and even ugly IMHO - it requires a
> > lot of special treatment, explicit data definitions and linker
> > scripts, and does not work for arbitrary data as we saw above.
> 
> It is standard, documented by the ABI, and works fine if done
> correctly. We just don't do it correctly yet.
> 
> Best regards,
> 
> Wolfgang Denk
> 

Well the type of runtime relocation that we do in u-boot is not really
specified in any documentation. What is in the abi is assuming a dynamic
linker and a proper elf file.

Gcc can be nice and create a fixup table for us if we ask for it but
that is not something that exist in any abi document I ever read. That
also explains why when this reloaction code was initially done we ended
up with the extra fixup code that tries to catch a few pointer that the
GOT table is not containing, nobody know the fixup table even existed
and it sure as hell is not mentioned in the documentation you have to
read the gcc code to understand what the -mrelocatable option really do.






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