[PATCH 1/2] powerpc: Add a proper syscall for switching endianness

[Michael Ellerman]

On Mon, 2015-03-16 at 11:07 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2015-03-16 at 09:59 +1100, Tony Breeds wrote:
> > On Fri, Mar 13, 2015 at 05:38:46PM +1100, Michael Ellerman wrote:
> > 
> > > According to Paul there are no working implementations of LE on 32-bit cpus, so
> > > the syscall doesn't really make sense there.
> > 
> > Ummm that doesn't sound right.  I don't think there is an LE linux userspace
> > but I'm pretty sure we had 32-bit working on 44x.  Check where Ian did the
> > initial LE patchset.
> 
> Yes but that's done by using a per-page endian flag, not a global MSR
> bit, so we never supported a syscall to switch there and never will.

Yeah sorry, I should have said "implementations of MSR_LE on 32-bit cpus".

We can always add a 32-bit version in future if we need to, but we can't remove
it once it's there, so for now we won't do it on 32-bit.

cheers