Re: [PATCH] x86/mm/pti: Move user W+X check into pti_finalize()

From: Joerg Roedel
Date: Thu Aug 09 2018 - 07:26:42 EST


Hi Kees,

On Wed, Aug 08, 2018 at 01:33:01PM -0700, Kees Cook wrote:
> I'm slightly nervous about complicating this and splitting up the
> check. I have a mild preference that all the checks get moved later,
> so that all architectures have the checks happening at the same time
> during boot. Splitting this up could give us some weird differences
> between architectures, etc.

As fas as I can see the checks are implemented on x86, arm, and arm64. I
agree that it would be better to run the checks at a unified place
across architectures and can send a patch-set for set once the dust
around the 32-bit PTI implementation for x86 has settled.

But currently the call-places are architecture specific and with that in
mind the split-up on x86 is the right thing to do. I'll change that back
when I implement your idea above.

Regards,

Joerg