From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932600AbeCIUGu convert rfc822-to-8bit (ORCPT ); Fri, 9 Mar 2018 15:06:50 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48166 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932554AbeCIUGr (ORCPT ); Fri, 9 Mar 2018 15:06:47 -0500 Date: Fri, 9 Mar 2018 12:06:31 -0800 From: Ram Pai To: Michael Ellerman Cc: mingo@redhat.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de, fweimer@redhat.com, msuchanek@suse.com, Ulrich.Weigand@de.ibm.com Subject: Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0 Reply-To: Ram Pai References: <1520583161-11741-1-git-send-email-linuxram@us.ibm.com> <87lgf1v9di.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <87lgf1v9di.fsf@concordia.ellerman.id.au> User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 18030920-0016-0000-0000-0000052EF90E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030920-0017-0000-0000-0000286C1E50 Message-Id: <20180309200631.GS1060@ram.oc3035372033.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-09_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803090239 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 09, 2018 at 09:19:53PM +1100, Michael Ellerman wrote: > Ram Pai writes: > > > Once an address range is associated with an allocated pkey, it cannot be > > reverted back to key-0. There is no valid reason for the above behavior. On > > the contrary applications need the ability to do so. > > Please explain this in much more detail. Is it an ABI change? Not necessarily an ABI change. older binary applications will continue to work. It can be considered as a bug-fix. > > And why did we just notice this? Yes. this was noticed by an application vendor. > > > The patch relaxes the restriction. > > > > Tested on powerpc and x86_64. > > Thanks, but please split the patch, one for each arch. Will do. RP