On Mon, Mar 05, 2018 at 01:58:32PM -0800, Linus Torvalds wrote: > On Mon, Mar 5, 2018 at 1:35 PM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > > I could probably add some debug instrumentation to check for that in my > > future testing, as there is no NX protection in the user address-range > > for the kernel-cr3. > > Does not NX work with PAE? > > Oh, it looks like the NX bit is marked as "RSVD (must be 0)" in the > PDPDT. Oh well. I had a version of these patches running which implemented NX on the PDE level by allocating 8k PMD pages. But that ended up needing 5 order-1 allocations for each page-table, which I got to fail pretty easily after some time. So I abandoned this approach for now. Maybe it can be implemented with order-0 allocations for PMD pages, the open problem is how to link the user and kernel PMD page-pairs together then. Regards, Joerg -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
