lkml.org 
[lkml]   [2012]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] nommu: Enable the strict alignment (CR_A) bit only if ARCH < v6
On Mon, Dec 03, 2012 at 04:44:11PM +0000, 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@st.com>
> > ---
> > 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?

Although this is correct, you still need some extra patches to avoid
unaligned accesses to strongly-ordered memory (given that we don't
currently have mainline support for the MPU). Take a look at my nommu/fixes
branch:

https://git.kernel.org/?p=linux/kernel/git/will/linux.git;a=shortlog;h=refs/heads/nommu/fixes

I'm happy to post some of that if it's useful to you.

Will

\
 
 \ /
  Last update: 2012-12-03 18:41    [W:0.122 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site