From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f199.google.com (mail-qt0-f199.google.com [209.85.216.199]) by kanga.kvack.org (Postfix) with ESMTP id 78D506B0005 for ; Fri, 9 Mar 2018 15:09:45 -0500 (EST) Received: by mail-qt0-f199.google.com with SMTP id y9so7658922qti.3 for ; Fri, 09 Mar 2018 12:09:45 -0800 (PST) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id z33si1475691qtc.156.2018.03.09.12.09.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Mar 2018 12:09:44 -0800 (PST) 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 w29K7tCg052940 for ; Fri, 9 Mar 2018 15:09:43 -0500 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 2gkyv8akxj-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Fri, 09 Mar 2018 15:09:43 -0500 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 9 Mar 2018 20:09:32 -0000 Date: Fri, 9 Mar 2018 12:09:17 -0800 From: Ram Pai 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> Message-Id: <20180309200917.GT1060@ram.oc3035372033.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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