Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752991AbdG2W7V (ORCPT ); Sat, 29 Jul 2017 18:59:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39941 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751754AbdG2W7T (ORCPT ); Sat, 29 Jul 2017 18:59:19 -0400 Date: Sat, 29 Jul 2017 15:59:04 -0700 From: Ram Pai To: Thiago Jung Bauermann Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, arnd@arndb.de, corbet@lwn.net, mhocko@kernel.org, dave.hansen@intel.com, mingo@redhat.com, paulus@samba.org, aneesh.kumar@linux.vnet.ibm.com, akpm@linux-foundation.org, khandual@linux.vnet.ibm.com Subject: Re: [RFC v6 17/62] powerpc: implementation for arch_set_user_pkey_access() Reply-To: Ram Pai References: <1500177424-13695-1-git-send-email-linuxram@us.ibm.com> <1500177424-13695-18-git-send-email-linuxram@us.ibm.com> <87d18m3r07.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87d18m3r07.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 17072922-0052-0000-0000-0000024780C6 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007449; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000214; SDB=6.00894787; UDB=6.00447447; IPR=6.00674954; BA=6.00005499; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016445; XFM=3.00000015; UTC=2017-07-29 22:59:17 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17072922-0053-0000-0000-0000517EDF00 Message-Id: <20170729225904.GF5664@ram.oc3035372033.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-29_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1706020000 definitions=main-1707290386 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1416 Lines: 38 On Thu, Jul 27, 2017 at 11:15:36AM -0300, Thiago Jung Bauermann wrote: > > Ram Pai writes: > > @@ -113,10 +117,14 @@ static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, > > return 0; > > } > > > > +extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, > > + unsigned long init_val); > > static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, > > unsigned long init_val) > > { > > - return 0; > > + if (!pkey_inited) > > + return -1; > > + return __arch_set_user_pkey_access(tsk, pkey, init_val); > > } > > If non-zero, the return value of this function will be passed to > userspace by the pkey_alloc syscall. Shouldn't it be returning an errno > macro such as -EPERM? Yes. it should be -EINVAL. fixed it. > > Also, why are there both arch_set_user_pkey_access and > __arch_set_user_pkey_access? Is it a speed optimization so that the > early return is inlined into the caller? Ditto for execute_only_pkey > and __arch_override_mprotect_pkey. arch_set_user_pkey_access() is the interface expected by the architecture independent code. The __arch_set_user_pkey_access() is an powerpc internal function that implements the bulk of the work. It can be called by any of the pkeys internal code only. This gives me the flexibility to change implementation without having to worry about changing the interface. RP