From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751390AbeCIUJg (ORCPT ); Fri, 9 Mar 2018 15:09:36 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44048 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751192AbeCIUJe (ORCPT ); Fri, 9 Mar 2018 15:09:34 -0500 Date: Fri, 9 Mar 2018 12:09:17 -0800 From: Ram Pai To: Ingo Molnar Cc: mpe@ellerman.id.au, 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> <20180309084332.hk6xt6obghoqokbc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180309084332.hk6xt6obghoqokbc@gmail.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 18030920-0040-0000-0000-0000043CFA2C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030920-0041-0000-0000-000020E01F83 Message-Id: <20180309200917.GT1060@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 09:43:32AM +0100, Ingo Molnar wrote: > > * Ram Pai wrote: > > > 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. > > > > The patch relaxes the restriction. > > > > Tested on powerpc and x86_64. > > > > cc: Dave Hansen > > cc: Michael Ellermen > > cc: Ingo Molnar > > Signed-off-by: Ram Pai > > --- > > arch/powerpc/include/asm/pkeys.h | 19 ++++++++++++++----- > > arch/x86/include/asm/pkeys.h | 5 +++-- > > 2 files changed, 17 insertions(+), 7 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h > > index 0409c80..3e8abe4 100644 > > --- a/arch/powerpc/include/asm/pkeys.h > > +++ b/arch/powerpc/include/asm/pkeys.h > > @@ -101,10 +101,18 @@ static inline u16 pte_to_pkey_bits(u64 pteflags) > > > > static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) > > { > > - /* A reserved key is never considered as 'explicitly allocated' */ > > - return ((pkey < arch_max_pkey()) && > > - !__mm_pkey_is_reserved(pkey) && > > - __mm_pkey_is_allocated(mm, pkey)); > > + /* pkey 0 is allocated by default. */ > > + if (!pkey) > > + return true; > > + > > + if (pkey < 0 || pkey >= arch_max_pkey()) > > + return false; > > + > > + /* reserved keys are never allocated. */ > > + if (__mm_pkey_is_reserved(pkey)) > > + return false; > > Please capitalize in comments consistently, i.e.: ok. > > /* Reserved keys are never allocated: */ > > > + > > + return(__mm_pkey_is_allocated(mm, pkey)); > > 'return' is not a function. right. will fix. Thanks, RP