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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 CE4AFC54FCC for ; Tue, 21 Apr 2020 22:17:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1C7220735 for ; Tue, 21 Apr 2020 22:17:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726012AbgDUWRU (ORCPT ); Tue, 21 Apr 2020 18:17:20 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:20788 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725850AbgDUWRU (ORCPT ); Tue, 21 Apr 2020 18:17:20 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 03LM3FMo063167 for ; Tue, 21 Apr 2020 18:17:19 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 30gfec1edu-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 21 Apr 2020 18:17:19 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 21 Apr 2020 23:16:31 +0100 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp04.uk.ibm.com (192.168.101.134) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 21 Apr 2020 23:16:27 +0100 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 03LMHCXp2621870 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Apr 2020 22:17:12 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8BF304204C; Tue, 21 Apr 2020 22:17:12 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3E88A4203F; Tue, 21 Apr 2020 22:17:11 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.238.1]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 21 Apr 2020 22:17:11 +0000 (GMT) Subject: Re: [PATCH v2] tpm_tis: work around status register bug in STMicroelectronics TPM From: Mimi Zohar To: Benoit HOUYERE , Omar Sandoval , Paul Menzel Cc: Peter Huewe , Jarkko Sakkinen , Jason Gunthorpe , James Bottomley , "linux-integrity@vger.kernel.org" , "kernel-team@fb.com" Date: Tue, 21 Apr 2020 18:17:10 -0400 In-Reply-To: <3766ead79aa4415198bc5a8324f02f6e@SFHDAG3NODE3.st.com> References: <19d930ef-4090-3339-1088-c3579e8a080f@molgen.mpg.de> <20200416190249.GC701157@vader> <1587476664.5149.14.camel@linux.ibm.com> <3766ead79aa4415198bc5a8324f02f6e@SFHDAG3NODE3.st.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 20042122-0016-0000-0000-00000308D887 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20042122-0017-0000-0000-0000336CF183 Message-Id: <1587507430.5053.16.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.676 definitions=2020-04-21_09:2020-04-21,2020-04-21 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 priorityscore=1501 adultscore=0 lowpriorityscore=0 mlxlogscore=999 spamscore=0 phishscore=0 malwarescore=0 bulkscore=0 impostorscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004210159 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Tue, 2020-04-21 at 20:56 +0000, Benoit HOUYERE wrote: > Issue occurs on several legacy models and corrected on latest TPM > versions. Several corrections are possible. Omar's proposal is quite > simple, short and efficient. Penalty time is only condition check > but for all TPM_status access. > > Other possibility is to check status register validity (bit 5 is > always at 0) at the first reading and modify wait_for_stat function > (already inserted for I2C patch). Benoit, thank you for the explanation. It sounds like by "already inserted for I2C patch", you mean that this proposed solution is part of the i2c patch set.  If that is the case, to simplify backporting, the fix should be the first patch in the i2c patch set. Mimi