On Fri, Dec 4, 2015 at 3:38 PM, Dave Hansen [off-list ref] wrote:

On 12/04/2015 03:31 PM, Andy Lutomirski wrote:

quoted

On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen [off-list ref] wrote:

quoted

Memory Protection Keys for User pages is a CPU feature which will
first appear on Skylake Servers, but will also be supported on
future non-server parts.  It provides a mechanism for enforcing
page-based protections, but without requiring modification of the
page tables when an application changes protection domains.  See
the Documentation/ patch for more details.

What, if anything, happened to the signal handling parts?

Patches 12 and 13 contain most of it:

        x86, pkeys: fill in pkey field in siginfo
        signals, pkeys: notify userspace about protection key faults

I decided to just not try to preserve the pkey_get/set() semantics
across entering and returning from signals, fwiw.

Hmm.  I'll see if I can find some time this weekend to play with that
bit.  Maybe I can test by faking it and tweaking MPX instead of PKRU.

--Andy