From mboxrd@z Thu Jan 1 00:00:00 1970 From: js@sig21.net (Johannes Stezenbach) Date: Thu, 25 Oct 2012 16:16:45 +0200 Subject: [PATCH] ARM: decompressor: clear SCTLR.A bit for v7 cores In-Reply-To: <50893389.2090002@gmail.com> References: <1349959402-24164-1-git-send-email-robherring2@gmail.com> <20121025093411.GA32662@sig21.net> <50893389.2090002@gmail.com> Message-ID: <20121025141645.GA16962@sig21.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Oct 25, 2012 at 07:41:45AM -0500, Rob Herring wrote: > On 10/25/2012 04:34 AM, Johannes Stezenbach wrote: > > On Thu, Oct 11, 2012 at 07:43:22AM -0500, Rob Herring wrote: > > > >> While v6 can support unaligned accesses, it is optional and current > >> compilers won't emit unaligned accesses. So we don't clear the A bit for > >> v6. > > > > not true according to the gcc changes page > > What are you going to believe: documentation or what the compiler > emitted? At least for ubuntu/linaro 4.6.3 which has the unaligned access > support backported and 4.7.2, unaligned accesses are emitted for v7 > only. I guess default here means it is the default unless you change the > default in your build of gcc. Since ARMv6 can handle unaligned access in the same way as ARMv7 it seems a clear bug in gcc which might hopefully get fixed. Thus in this case I think it is reasonable to follow the gcc documentation, otherwise the code would break for ARMv6 when gcc gets fixed. Johannes