[PATCH 1/4] ARM: mm: use pteval_t to represent page protection values

[will.deacon@arm.com (Will Deacon)]

Hi Nicolas,

On Thu, Sep 20, 2012 at 07:28:14PM +0100, Nicolas Pitre wrote:
> On Thu, 20 Sep 2012, Will Deacon wrote:
> 
> > When updating the page protection map after calculating the user_pgprot
> > value, the base protection map is temporarily stored in an unsigned long
> > type, causing truncation of the protection bits when LPAE is enabled.
> > This effectively means that calls to mprotect() will corrupt the upper
> > page attributes, clearing the XN bit unconditionally.
> > 
> > This patch uses pteval_t to store the intermediate protection values,
> > preserving the upper bits for 64-bit descriptors.
> > 
> > Signed-off-by: Will Deacon <will.deacon@arm.com>
> 
> Acked-by: Nicolas Pitre <nico@linaro.org>

Thanks.

> Maybe CC to stable?

Of course.

> Are you sure there are no other occurences of this elsewhere?  
> Unfortunately, STRICT_MM_TYPECHECKS can't help here.

I grepped for lines containing `pgprot' and `long' and didn't find any
other problematic code. Everything else seems to use the pgprot_t types
consistently.

Will