Possible regression in kexec on ARM ARMv6 and ARMv7 cores

[Simon Horman]

On Thu, Oct 20, 2011 at 05:08:24PM +0900, Simon Horman wrote:
> On Thu, Oct 20, 2011 at 08:01:06AM +0100, Will Deacon wrote:
> > On Thu, Oct 20, 2011 at 05:24:45AM +0100, Simon Horman wrote:
> > > Hi Will, Hi All,
> > 
> > Hi Simon,
> 
> Hi Will,
> 
> > > it appears that "ARM: proc: add definition of cpu_reset for
> > >  ARMv6 and ARMv7 cores" (f4daf06fc23b99df5ca5b3e892428b91e148cc52),
> > > which was introduced for 3.1-rc1, causes a regression and that
> > > kexec no longer works on ARM. The board that I am testing
> > > on is a Renesas Mackerel which has an SH7372 (ARMv7) processor.
> > 
> > Wow, I'm surprised the old code worked at all on an ARMv7 CPU! It's certainly
> > highly unlikely to work by the letter of the architecture, so I guess the
> > planets aligned in just the right way for your particular implementation.
> > 
> > Please can you try my kexec/mmu-off patches? They should add the bits and
> > pieces you need for kexec to work reliably on a UP system. I plan to finish
> > these off next week in Prague so hopefully they'll hit mainline in the near
> > future.
> > 
> > https://github.com/wdeacon/linux-wd/commits/kexec/mmu-off
> 
> Thanks, I will try your patches and let you know how I go.

I have tested the kexec/mmu-off branch of your tree on the UP board
I mentioned above and kexec works :)

> You mention UP in particular, which I will test.
> Do you have any thoughts on SMP?