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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_SANE_1 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 32C4DC433DB for ; Wed, 20 Jan 2021 04:06:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB6D02312B for ; Wed, 20 Jan 2021 04:06:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731587AbhATEGJ (ORCPT ); Tue, 19 Jan 2021 23:06:09 -0500 Received: from out30-54.freemail.mail.aliyun.com ([115.124.30.54]:53985 "EHLO out30-54.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731536AbhATEFK (ORCPT ); Tue, 19 Jan 2021 23:05:10 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0UMIdHZ._1611115429; Received: from 30.25.183.227(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0UMIdHZ._1611115429) by smtp.aliyun-inc.com(127.0.0.1); Wed, 20 Jan 2021 12:03:50 +0800 Subject: Re: [PATCH] tpm/tpm_tis: Fix variable reset during IRQ probing To: Jarkko Sakkinen Cc: Peter Huewe , Jason Gunthorpe , linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, Jia Zhang References: <20210113120021.59045-1-tianjia.zhang@linux.alibaba.com> <44c35c27-0cd4-e451-1b9c-d6fe48e58e51@linux.alibaba.com> From: Tianjia Zhang Message-ID: <60b7bb82-c762-cf67-6b73-7ecb2a0f1085@linux.alibaba.com> Date: Wed, 20 Jan 2021 12:03:49 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/15/21 5:23 PM, Jarkko Sakkinen wrote: > On Thu, Jan 14, 2021 at 12:12:16PM +0800, Tianjia Zhang wrote: >> >> >> On 1/14/21 10:51 AM, Jarkko Sakkinen wrote: >>> On Wed, Jan 13, 2021 at 08:00:21PM +0800, Tianjia Zhang wrote: >>>> In tpm_tis_core_init(), tpm2_probe() will be called first, this >>>> function will eventually call tpm_tis_send(), and then >>>> tpm_tis_probe_irq_single() will detect whether the interrupt is >>>> normal, mainly the installation interrupted, set `priv->irq_tested` >>>> to false. The logic will eventually be executed to tpm_tis_send() >>>> to trigger an interrupt. >>>> >>>> There is currently such a scenario, which will cause the IRQ probe >>>> code to never be executed, so that the TPM device is in polling >>>> mode: after setting irq_tested to false, an interrupt occurs >>>> between entering the ttpm_tis_send() function, and the interrupt >>>> will be first set irq_tested to true will cause the IRQ probe code >>>> to never be executed. >>> >>> Can you describe the scenario more detail? >>> >> >> The problematic scenario we encountered is like this. The following figure >> shows the execution flow of tpm_tis_core_init(). An interrupt occurred >> before the IRQ probe. This interrupt was caused by tpm2_probe(), but it was >> triggered before the IRQ probe was executed, and the interrupt handler would >> set irq_tested to true, so the IRQ probe code can never execute, that is, >> the code marked 2 in the figure will never happen. > > TPM_INT_ENABLE is cleared on reset [*]. > > [*] Section 5.9.1 > https://trustedcomputinggroup.org/resource/pc-client-work-group-pc-client-specific-tpm-interface-specification-tis/ > > /Jarkko > Hi, I got it, this seems to be a firmware issue. Thanks for your reply. Best regards, Tianjia