[PATCH] powerpc: perf: Handle events that raise an exception without overflowing

[Benjamin Herrenschmidt]

On Wed, 2011-03-16 at 13:50 +0100, Ingo Molnar wrote:
> * Anton Blanchard <anton at samba.org> wrote:
> 
> > 
> > Events on POWER7 can roll back if a speculative event doesn't
> > eventually complete. Unfortunately in some rare cases they will
> > raise a performance monitor exception. We need to catch this to
> > ensure we reset the PMC. In all cases the PMC will be 256 or less
> > cycles from overflow.
> > 
> > Signed-off-by: Anton Blanchard <anton at samba.org>
> > Cc: stable at kernel.org
> > ---
> > 
> > I would prefer not to add the PVR check, but I think we want to limit
> > this workaround to POWER7. Would a cpu feature be preferable?
> 
> There was no objection from the PowerPC folks so i'll send this fix Linuswards, ok?

Ah yes.

Ack.

Cheers,
Ben.