Re: [PATCH] nommu: Enable the strict alignment (CR_A) bit only ifARCH < v6

[Armando Visconti]

On 12/03/2012 06:46 PM, Will Deacon wrote:
> On Mon, Dec 03, 2012 at 05:25:53PM +0000, Russell King - ARM Linux wrote:
> > On Mon, Dec 03, 2012 at 05:44:11PM +0100, Armando Visconti wrote:
> > > On 11/29/2012 12:04 PM, Armando VISCONTI wrote:
> > > > This patch keeps disabled the strict alignment CP15 bit for
> > > > all armv6 and armv7 processor without the mmu. This behaviour
> > > > is now same as in the mmu case.
> > > >
> > > > Signed-off-by: Armando Visconti<armando.visconti@xxxxxx>
> > > > ---
> > > >    arch/arm/kernel/head-nommu.S |    2 +-
> > > >    1 files changed, 1 insertions(+), 1 deletions(-)
> > > >
> > > > diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
> > > > index 278cfc1..2c228a0 100644
> > > > --- a/arch/arm/kernel/head-nommu.S
> > > > +++ b/arch/arm/kernel/head-nommu.S
> > > > @@ -68,7 +68,7 @@ __after_proc_init:
> > > >    	 * CP15 system control register value returned in r0 from
> > > >    	 * the CPU init function.
> > > >    	 */
> > > > -#ifdef CONFIG_ALIGNMENT_TRAP
> > > > +#if defined(CONFIG_ALIGNMENT_TRAP)&&   __LINUX_ARM_ARCH__<   6
> > > >    	orr	r0, r0, #CR_A
> > > >    #else
> > > >    	bic	r0, r0, #CR_A
> > >
> > > Any feedback on this simple patch?
> >
> > Well, it brings the nommu version into line with the mmu version, so
> > it's sensible.  Please put it in the patch system, thanks.

Done!

> In which case, I'll definitely dust-off the patches to prevent unaligned
> accesses to strongly-ordered memory because that results in good ol'
> UNPREDICTABLE behaviour.

Yes, we definetely need them.

Thx,
Arm


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