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From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: alignment: Prevent ignoring of faults with ARMv6 unaligned access model
Date: Wed, 27 Jul 2011 15:32:34 +0100	[thread overview]
Message-ID: <20110727143233.GC2171@arm.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1107271009580.12766@xanadu.home>

On Wed, Jul 27, 2011 at 10:10:46AM -0400, Nicolas Pitre wrote:
> On Wed, 27 Jul 2011, Dave Martin wrote:
> 
> > On Tue, Jul 26, 2011 at 05:28:57PM -0400, Nicolas Pitre wrote:
> > > Why not clearing the U bit as well as the A bit to preserve consistency 
> > > with the pre ARMv6 behavior?
> > 
> > The old unaligned access behaviour is deprecated in ARMv6 (I believe)
> > and is not supported at all in ARMv7 -- i.e., you can't turn the U bit
> > off.  So this would be an additional special behaviour for ARMv6 only.
> > 
> > I'm not sure that introducing yet another behaviour is useful here;
> > anyone with legacy userspace software relying on the old unaligned
> > access model presumably fixed it years ago.
> > 
> > Really, the patch was just intended resolve the inconsistency where
> > the policy the kernel enforces for the alignment fixup mode on bootup
> > is not enforced at run-time.
> 
> OK, that makes sense then.

Can I take that as an Ack?

Cheers
---Dave

  reply	other threads:[~2011-07-27 14:32 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-26 14:14 [PATCH v2] ARM: alignment: Prevent ignoring of faults with ARMv6 unaligned access model Dave Martin
2011-07-26 21:28 ` Nicolas Pitre
2011-07-26 21:35   ` Russell King - ARM Linux
2011-07-26 21:51     ` Nicolas Pitre
2011-07-27  9:44   ` Dave Martin
2011-07-27 14:10     ` Nicolas Pitre
2011-07-27 14:32       ` Dave Martin [this message]
2011-07-27 15:27         ` Nicolas Pitre

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