From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB8F2C282DD for ; Tue, 23 Apr 2019 16:47:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BCB321841 for ; Tue, 23 Apr 2019 16:47:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729399AbfDWQrA (ORCPT ); Tue, 23 Apr 2019 12:47:00 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44168 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728758AbfDWQq7 (ORCPT ); Tue, 23 Apr 2019 12:46:59 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3NGjRMU145403 for ; Tue, 23 Apr 2019 12:46:58 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2s25y01h37-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 23 Apr 2019 12:46:58 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 23 Apr 2019 17:46:53 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3NGkqRU59899956 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 23 Apr 2019 16:46:52 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB2204203F; Tue, 23 Apr 2019 16:46:52 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 296C142041; Tue, 23 Apr 2019 16:46:52 +0000 (GMT) Received: from [9.145.7.116] (unknown [9.145.7.116]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 23 Apr 2019 16:46:52 +0000 (GMT) Subject: Re: [PATCH] powerpc/mm: Comment arch_unmap() From: Laurent Dufour To: mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Thomas Gleixner References: <20190423151712.79391-1-ldufour@linux.ibm.com> Date: Tue, 23 Apr 2019 18:46:51 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190423151712.79391-1-ldufour@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19042316-0008-0000-0000-000002DCEFC5 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19042316-0009-0000-0000-000022494193 Message-Id: <5d1cf986-d51b-3c47-8f6c-ae5ba205f59b@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-23_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904230114 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 23/04/2019 à 17:17, Laurent Dufour a écrit : > During a different patch review, the check in arch_munmap() was found > spucious due the lake of explanation. > > Adding a comment to clarify the test. > > Suggested-by: Thomas Gleixner > Cc: Michael Ellerman > Signed-off-by: Laurent Dufour > --- > arch/powerpc/include/asm/mmu_context.h | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h > index 6ee8195a2ffb..638f481b3c9f 100644 > --- a/arch/powerpc/include/asm/mmu_context.h > +++ b/arch/powerpc/include/asm/mmu_context.h > @@ -240,6 +240,17 @@ static inline void arch_unmap(struct mm_struct *mm, > struct vm_area_struct *vma, > unsigned long start, unsigned long end) > { > + /* > + * There are 2 assumptions here: > + * 1. the VDSO is one page size (guaranteed by vdso_data_store) Indeed this is not true, only the descriptor is one page size. This makes that test not handling all the cases, especially if a upper part of the VDSO is unmap (start > mm->context.vdso_base). I'll sent a new fix asap. > + * 2. 'start' and 'end' are page aligned (guaranteed by the caller) > + * The test is wrote in a way to handle unmap operation surrounding the > + * VDSO area like: > + * | VDSO | > + * ^ start ^ end > + * The test also covers the munmap() operation done to the exact VDSO's > + * boundaries. > + */ > if (start <= mm->context.vdso_base && mm->context.vdso_base < end) > mm->context.vdso_base = 0; > } >