From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave.martin@linaro.org (Dave Martin) Date: Wed, 27 Jul 2011 15:32:34 +0100 Subject: [PATCH v2] ARM: alignment: Prevent ignoring of faults with ARMv6 unaligned access model In-Reply-To: References: <1311689651-7372-1-git-send-email-dave.martin@linaro.org> <20110727094359.GA2171@arm.com> Message-ID: <20110727143233.GC2171@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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