Re: Change of TEXT_OFFSET for multi_v7_defconfig

[Jason Gunthorpe <jgunthorpe@obsidianresearch.com>]

On Tue, Apr 22, 2014 at 10:44:14AM +0100, Daniel Thompson wrote:
> On 17/04/14 21:35, Jason Gunthorpe wrote:
> >>> The above is useful for loading the raw uncompressed Image without 
> >>> carrying the full ELF baggage.
> >>
> >> What exactly is the full ELF baggage? Aren't there existing mechanisms to omit
> >> debugging symbols, for example, if size is of concern?
> > 
> > FWIW, it is a small non-intrusive change to produce ELFs with the
> > proper LMA, if it is useful for specialized tooling, here is the 3.14
> > version of the patch I created (I see it needs a bit of cleanup..)
> > You must also force PATCH_PHYS_VIRT off.
> > 
> > The ELF also has the correct entry point address, so ELF tooling can
> > just jump into it, after setting the proper register values according
> > to the boot protocol.
> 
> That might be a useful approach for single platform kernels but I don't
> think such an approach can work for multi-arch kernels since, because
> the RAM can be located anywhere in the address map, the physical load
> address is platform dependant.

Right, I think everyone realizes that.

What this patch does is make kernels that are built with
PLAT_PHYS_OFFSET set and CONFIG_ARM_PATCH_PHYS_VIRT disabled produce
an ELF that reflects the build configuration.

Based on comments from others in the thread this is looking useful for
a variety of cases.

I'm not sure who would need to ack this patch? I can clean it up of course.

Thanks,
Jason