Subject: Re: [PATCH][for 2.6.28] powerpc/fsl-booke: Fix problem with _tlbil_va being interrupted

From: Benjamin Herrenschmidt <[email-masked]>
Date: Sun, 14 Dec 2008 13:46:02 +1100

On Sat, 2008-12-13 at 17:33 -0600, Kumar Gala wrote:
> An example calling sequence which we did see:
> 
> copy_user_highpage -> kmap_atomic -> flush_tlb_page -> _tlbil_va
> 
> We got interrupted after setting up the MAS registers before the
> tlbwe and the interrupt handler that caused the interrupt also did
> a kmap_atomic (ide code) and thus on returning from the interrupt
> the MAS registers no longer contained the proper values.
> 
> Since we dont save/restore MAS registers for normal interrupts we
> need to disable interrupts in _tlbil_va to ensure atomicity.
> 
> Signed-off-by: Kumar Gala <[email-masked]>

Acked-by: Benjamin Herrenschmidt <[email-masked]>
---

Paul, this is a 2.6.28 regression, it should probably go to Linus in
case he hasn't released yet :-)

Cheers,
Ben.