From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752824AbdHOFCb convert rfc822-to-8bit (ORCPT ); Tue, 15 Aug 2017 01:02:31 -0400 Received: from ozlabs.org ([103.22.144.67]:58787 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751712AbdHOFCN (ORCPT ); Tue, 15 Aug 2017 01:02:13 -0400 From: Michael Ellerman To: Khalid Aziz , akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, davem@davemloft.net, dave.hansen@linux.intel.com Cc: bsingharora@gmail.com, dja@axtens.net, tglx@linutronix.de, mgorman@suse.de, aarcange@redhat.com, kirill.shutemov@linux.intel.com, heiko.carstens@de.ibm.com, ak@linux.intel.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, sparclinux@vger.kernel.org, Khalid Aziz Subject: Re: [PATCH v7 7/9] mm: Add address parameter to arch_validate_prot() In-Reply-To: <2e97b439-dd71-8997-4824-15f2b1f53787@oracle.com> References: <43c120f0cbbebd1398997b9521013ced664e5053.1502219353.git.khalid.aziz@oracle.com> <87tw1flftz.fsf@concordia.ellerman.id.au> <2e97b439-dd71-8997-4824-15f2b1f53787@oracle.com> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Tue, 15 Aug 2017 15:02:08 +1000 Message-ID: <877ey5v2y7.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Khalid Aziz writes: > On 08/10/2017 07:20 AM, Michael Ellerman wrote: >> Khalid Aziz writes: >> >>> A protection flag may not be valid across entire address space and >>> hence arch_validate_prot() might need the address a protection bit is >>> being set on to ensure it is a valid protection flag. For example, sparc >>> processors support memory corruption detection (as part of ADI feature) >>> flag on memory addresses mapped on to physical RAM but not on PFN mapped >>> pages or addresses mapped on to devices. This patch adds address to the >>> parameters being passed to arch_validate_prot() so protection bits can >>> be validated in the relevant context. >>> >>> Signed-off-by: Khalid Aziz >>> Cc: Khalid Aziz >>> --- >>> v7: >>> - new patch >>> >>> arch/powerpc/include/asm/mman.h | 2 +- >>> arch/powerpc/kernel/syscalls.c | 2 +- >>> include/linux/mman.h | 2 +- >>> mm/mprotect.c | 2 +- >>> 4 files changed, 4 insertions(+), 4 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h >>> index 30922f699341..bc74074304a2 100644 >>> --- a/arch/powerpc/include/asm/mman.h >>> +++ b/arch/powerpc/include/asm/mman.h >>> @@ -40,7 +40,7 @@ static inline bool arch_validate_prot(unsigned long prot) >>> return false; >>> return true; >>> } >>> -#define arch_validate_prot(prot) arch_validate_prot(prot) >>> +#define arch_validate_prot(prot, addr) arch_validate_prot(prot) >> >> This can be simpler, as just: >> >> #define arch_validate_prot arch_validate_prot >> > > Hi Michael, > > Thanks for reviewing! > > My patch expands parameter list for arch_validate_prot() from one to two > parameters. Existing powerpc version of arch_validate_prot() is written > with one parameter. If I use the above #define, compilation fails with: > > mm/mprotect.c: In function ‘do_mprotect_pkey’: > mm/mprotect.c:399: error: too many arguments to function > ‘arch_validate_prot’ > > Another way to solve it would be to add the new addr parameter to > powerpc version of arch_validate_prot() but I chose the less disruptive > solution of tackling it through #define and expanded the existing > #define to include the new parameter. Make sense? Yes, it makes sense. But it's a bit gross. At first glance it looks like our arch_validate_prot() has an incorrect signature. I'd prefer you just updated it to have the correct signature, I think you'll have to change one more line in do_mmap2(). So it's not very intrusive. cheers