From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Wed, 17 Oct 2012 10:57:57 +0100
Subject: [RFC PATCH v2] prevent top pte being overwritten before flushing
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To: linux-arm-kernel@lists.infradead.org
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On Wed, Oct 17, 2012 at 10:54:53AM +0100, Jason Lin wrote:
> 2012/10/17 Will Deacon <will.deacon@arm.com>:
> > On Wed, Oct 17, 2012 at 09:42:19AM +0100, Andrew Yan-Pai Chen wrote:
> >> On Mon, Oct 15, 2012 at 1:42 AM, Andrew Yan-Pai Chen
> >>
> >> Any ideas?
> >
> > I wonder if we could use different ptes for each CPU (by hacking
> > pte_offset_kernel) and then get away with just disabling preemption in both
> > cases?
> >
> > Will
> 
> Single core processor will also cause this issue in flush_pfn_alias().
> So it should use different ptes for each task.
> Will it be so complicated?

You can just disable preemption in that case -- it's the spin_lock that I'd
like to avoid.

Will