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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 06A71C43215 for ; Wed, 27 Nov 2019 11:48:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA02020722 for ; Wed, 27 Nov 2019 11:48:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726556AbfK0LsK (ORCPT ); Wed, 27 Nov 2019 06:48:10 -0500 Received: from foss.arm.com ([217.140.110.172]:46656 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726204AbfK0LsK (ORCPT ); Wed, 27 Nov 2019 06:48:10 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A34AB30E; Wed, 27 Nov 2019 03:48:09 -0800 (PST) Received: from dell3630.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 05CFC3F6C4; Wed, 27 Nov 2019 03:48:07 -0800 (PST) From: Dietmar Eggemann To: Viresh Kumar , Sudeep Holla , "Rafael J . Wysocki" Cc: Liviu Dudau , Lorenzo Pieralisi , Morten Rasmussen , Lukasz Luba , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] cpufreq: vexpress-spc: Fix wrong alternation of policy->related_cpus during CPU hp Date: Wed, 27 Nov 2019 12:48:01 +0100 Message-Id: <20191127114801.23837-1-dietmar.eggemann@arm.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit ca74b316df96 ("arm: Use common cpu_topology structure and functions.") the core cpumask has to be modified during cpu hotplug operations. ("arm: Fix topology setup in case of CPU hotplug for CONFIG_SCHED_MC") [1] fixed that but revealed another issue on TC2, i.e in its cpufreq driver. During CPU hp stress operations on multiple CPUs, policy->related_cpus can be altered. This is wrong since this cpumask should contain the online and offline CPUs. The WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus)) in cpufreq_online() triggers in this case. The core cpumask can't be used to set the policy->cpus in ve_spc_cpufreq_init() anymore in case it is called via cpuhp_cpufreq_online()->cpufreq_online()->cpufreq_driver->init(). An empty online() callback can be used to avoid that the init() driver function is called during CPU hotplug in so that policy->related_cpus will not be changed. Implementing an online() also requires an offline() callback. Tested on TC2 with CPU hp stress test (CPU hp from multiple CPUs at the same time). [1] https://lore.kernel.org/r/20191127103353.12417-1-dietmar.eggemann@arm.com Signed-off-by: Dietmar Eggemann --- drivers/cpufreq/vexpress-spc-cpufreq.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/cpufreq/vexpress-spc-cpufreq.c b/drivers/cpufreq/vexpress-spc-cpufreq.c index 506e3f2bf53a..857dcb535e97 100644 --- a/drivers/cpufreq/vexpress-spc-cpufreq.c +++ b/drivers/cpufreq/vexpress-spc-cpufreq.c @@ -492,6 +492,16 @@ static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy) cdev[cur_cluster] = of_cpufreq_cooling_register(policy); } +static int ve_spc_cpufreq_online(struct cpufreq_policy *policy) +{ + return 0; +} + +static int ve_spc_cpufreq_offline(struct cpufreq_policy *policy) +{ + return 0; +} + static struct cpufreq_driver ve_spc_cpufreq_driver = { .name = "vexpress-spc", .flags = CPUFREQ_STICKY | @@ -503,6 +513,8 @@ static struct cpufreq_driver ve_spc_cpufreq_driver = { .init = ve_spc_cpufreq_init, .exit = ve_spc_cpufreq_exit, .ready = ve_spc_cpufreq_ready, + .online = ve_spc_cpufreq_online, + .offline = ve_spc_cpufreq_offline, .attr = cpufreq_generic_attr, }; -- 2.17.1