Fix small race in 44x tlbie function

[Josh Boyer]

On Wed, 8 Aug 2007 10:20:45 -0500
Kumar Gala <galak at kernel.crashing.org> wrote:

> 
> On Aug 6, 2007, at 11:20 PM, David Gibson wrote:
> 
> > The 440 family of processors don't have a tlbie instruction.  So, we
> > implement TLB invalidates by explicitly searching the TLB with tlbsx.,
> > then clobbering the relevant entry, if any.  Unfortunately the PID for
> > the search needs to be stored in the MMUCR register, which is also
> > used by the TLB miss handler.  Interrupts were enabled in _tlbie(), so
> > an interrupt between loading the MMUCR and the tlbsx could cause
> > incorrect search results, and thus a failure to invalide TLB entries
> > which needed to be invalidated.
> >
> > This patch fixes the problem in both arch/ppc and arch/powerpc by
> > inhibiting interrupts (even critical and debug interrupts) across the
> > relevant instructions.
> >
> > Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
> > ---
> > Paul, this one's a bugfix, which I think should go into 2.6.23.
> 
> Did you actually see this happen?

Yes.

josh