[PATCH V3 01/30] mm: Make vm_get_page_prot arch specific.

[Paul Mackerras]

On Thu, Feb 18, 2016 at 10:20:25PM +0530, 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.

This seems like unnecessary churn to me.  Let's just make hash use the
same values as radix for things like _PAGE_RW, _PAGE_EXEC etc., and
then we don't need any of this.

Paul.