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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 4F4F0C433DF for ; Mon, 3 Aug 2020 18:44:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FE5320738 for ; Mon, 3 Aug 2020 18:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728783AbgHCSop (ORCPT ); Mon, 3 Aug 2020 14:44:45 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60358 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728515AbgHCSoo (ORCPT ); Mon, 3 Aug 2020 14:44:44 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 073Ib0ZV174990; Mon, 3 Aug 2020 14:44:34 -0400 Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 32pqdhh08t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 03 Aug 2020 14:44:34 -0400 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 073IZZvK021220; Mon, 3 Aug 2020 18:44:32 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma04ams.nl.ibm.com with ESMTP id 32n0182fgb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 03 Aug 2020 18:44:32 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 073IiU6Q28901674 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 3 Aug 2020 18:44:30 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED73E11C050; Mon, 3 Aug 2020 18:44:29 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A5C0C11C04C; Mon, 3 Aug 2020 18:44:29 +0000 (GMT) Received: from osiris (unknown [9.171.25.113]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 3 Aug 2020 18:44:29 +0000 (GMT) Date: Mon, 3 Aug 2020 20:44:28 +0200 From: Heiko Carstens To: Thomas Gleixner Cc: Sven Schnelle , Vincenzo Frascino , linux-kernel@vger.kernel.org, Peter Zijlstra , linux-s390@vger.kernel.org Subject: Re: [PATCH 2/2] s390: convert to GENERIC_VDSO Message-ID: <20200803184428.GA3973@osiris> References: <20200803055645.79042-1-svens@linux.ibm.com> <20200803055645.79042-3-svens@linux.ibm.com> <87ft93ncaa.fsf@nanos.tec.linutronix.de> <87a6zbn29n.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a6zbn29n.fsf@nanos.tec.linutronix.de> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-03_15:2020-08-03,2020-08-03 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 mlxscore=0 bulkscore=0 impostorscore=0 mlxlogscore=772 priorityscore=1501 clxscore=1011 suspectscore=1 phishscore=0 spamscore=0 lowpriorityscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008030130 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 03, 2020 at 06:05:24PM +0200, Thomas Gleixner wrote: > +/** > + * vdso_update_begin - Start of a VDSO update section > + * > + * Allows architecture code to safely update the architecture specific VDSO > + * data. > + */ > +void vdso_update_begin(void) > +{ > + struct vdso_data *vdata = __arch_get_k_vdso_data(); > + > + raw_spin_lock(&timekeeper_lock); > + vdso_write_begin(vdata); > +} I would assume that this only works if vdso_update_begin() is called with irqs disabled, otherwise it could deadlock, no? Maybe something like: void vdso_update_begin(unsigned long *flags) { struct vdso_data *vdata = __arch_get_k_vdso_data(); raw_spin_lock_irqsave(&timekeeper_lock, *flags); vdso_write_begin(vdata); } void vdso_update_end(unsigned long *flags) { struct vdso_data *vdata = __arch_get_k_vdso_data(); vdso_write_end(vdata); __arch_sync_vdso_data(vdata); raw_spin_unlock_irqrestore(&timekeeper_lock, *flags); } ? Just wondering.