From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B05F31A0617 for ; Fri, 19 Feb 2016 10:52:39 +1100 (AEDT) Date: Fri, 19 Feb 2016 10:15:46 +1100 From: Paul Mackerras To: "Aneesh Kumar K.V" Cc: benh@kernel.crashing.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Subject: Re: [PATCH V3 01/30] mm: Make vm_get_page_prot arch specific. Message-ID: <20160218231546.GC2765@fergus.ozlabs.ibm.com> References: <1455814254-10226-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1455814254-10226-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1455814254-10226-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.