On 02/18/2016 08:50 AM, Aneesh Kumar K.V wrote:

With next generation power processor, we are having a new mmu model
[1] that require us to maintain a different linux page table format.

Inorder to support both current and future ppc64 systems with a single
kernel we need to make sure kernel can select between different page
table format at runtime. With the new MMU (radix MMU) added, we will
have to dynamically switch between different protection map. Hence
override vm_get_page_prot instead of using arch_vm_get_page_prot. We
also drop arch_vm_get_page_prot since only powerpc used it.

Hi Aneesh,

I've got some patches I'm hoping to get in to 4.6 that start using
arch_vm_get_page_prot() on x86:

http://git.kernel.org/cgit/linux/kernel/git/daveh/x86-pkeys.git/commit/?h=pkeys-v024&id=aa1e61398fb598869981cfe48275cff832945669

So I'd prefer that it stay in place. :)