From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zydgt6C2yzDr2X for ; Sat, 10 Mar 2018 07:06:50 +1100 (AEDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w29K4OK6043907 for ; Fri, 9 Mar 2018 15:06:48 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 2gkyv8ah7g-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Fri, 09 Mar 2018 15:06:47 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 9 Mar 2018 20:06:45 -0000 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 In-Reply-To: <87lgf1v9di.fsf@concordia.ellerman.id.au> Message-Id: <20180309200631.GS1060@ram.oc3035372033.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Mar 09, 2018 at 09:19:53PM +1100, Michael Ellerman wrote: > Ram Pai writes: >=20 > > 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= =2E On > > the contrary applications need the ability to do so. >=20 > 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. >=20 > And why did we just notice this? Yes. this was noticed by an application vendor. >=20 > > The patch relaxes the restriction. > > > > Tested on powerpc and x86_64. >=20 > Thanks, but please split the patch, one for each arch. Will do. RP