Messages in this thread Patch in this message | | | Date | Mon, 3 Dec 2012 16:54:42 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] nommu: Enable the strict alignment (CR_A) bit only if ARCH < v6 |
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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
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