[PATCH 2/2] arm: Add ARM ERRATA 782773 workaround

[Catalin Marinas]

On 13 September 2012 02:00, Simon Horman <horms at verge.net.au> wrote:
> On Wed, Sep 12, 2012 at 10:59:35AM -0700, Stephen Boyd wrote:
>> On 09/12/12 00:14, Simon Horman wrote:
>> > @@ -1423,6 +1423,15 @@ config ARM_ERRATA_775420
>> >           deadlock. This workaround puts DSB before executing ISB at the
>> >           beginning of the abort exception handler.
>> >
>> > +config ARM_ERRATA_782773
>> > +   bool "ARM errata: Updating a translation entry might cause an unexpected translation fault"
>> > +   depends on CPU_V7
>> > +   help
>> > +     This option enables the workaround for the 782773 Cortex-A9 (all r0,
>> > +     ,r2 and r3 revisions) erratum. It might cause MMU exception in case
>>
>> Seems to be an extra comma here.
>
> Thanks, here is an updated version.
>
> From: Kouei Abe <kouei.abe.cp at rms.renesas.com>
>
> arm: Add ARM ERRATA 782773 workaround
>
> Signed-off-by: Kouei Abe <kouei.abe.cp at rms.renesas.com>
> Signed-off-by: Simon Horman <horms at verge.net.au>

I would add some text to the commit log as well, even though it
matches the Kconfig entry.

Have you hit this in practice? In general the kernel shouldn't access
kernel virtual address corresponding to a page table that is being
changed. For user address space it is possible but the kernel can
handle use translation faults, even though they may be spurious.

-- 
Catalin