Subject: Re: Introduce support for little endian PowerPC

From: Benjamin Herrenschmidt <[email-masked]>
Date: Sat, 02 Oct 2010 08:28:02 +1000

On Fri, 2010-10-01 at 17:03 -0500, Olof Johansson wrote:
> > Maybe. Most of it doesn't seem to be that bit-rottable.
> > 
> > The changes to the asm stuff in misc_32.S for example are functions we
> > never ever touch once written (libgcc replacements) so I don't see them
> > rotting more with LE support than they did with BE :-)
> 
> Does KVM/qemu support running LE guest on BE host? That'd help keeping
> the bitrot lower. :) 

Not yet I suppose :-) But then, I'm not sure it would make a big
difference, if you have a 440 board in the first place, you can boot
either LE or BE, no need for a special FW or anything.

What we've done is basically keep the zImage wrapper BE (for now at
least), and have it trampoline to LE when executing the actual kernel
(using a cuImage, of course a device-tree enabled u-Boot would probably
need something akin to a proper ePAPR zImage to do that but that's
reasonably easy to do nowadays).

Cheers,
Ben.