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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 D96BEC433DF for ; Mon, 27 Jul 2020 16:05:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD8E32075A for ; Mon, 27 Jul 2020 16:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730041AbgG0QF0 (ORCPT ); Mon, 27 Jul 2020 12:05:26 -0400 Received: from foss.arm.com ([217.140.110.172]:47214 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726662AbgG0QF0 (ORCPT ); Mon, 27 Jul 2020 12:05:26 -0400 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 6F1CCD6E; Mon, 27 Jul 2020 09:05:25 -0700 (PDT) Received: from bogus (unknown [10.37.12.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 851B23F718; Mon, 27 Jul 2020 09:05:22 -0700 (PDT) Date: Mon, 27 Jul 2020 17:05:15 +0100 From: Sudeep Holla To: Sumit Gupta Cc: Kefeng Wang , Catalin Marinas , Will Deacon , Mikko Perttunen , Viresh Kumar , Hulk Robot , "linux-kernel@vger.kernel.org List" , linux-arm-kernel@lists.infradead.org, Bibek Basu , Sudeep Holla Subject: Re: [PATCH -next] arm64: Export __cpu_logical_map Message-ID: <20200727160515.GA8003@bogus> References: <20200724030433.22287-1-wangkefeng.wang@huawei.com> <82f750c4-d423-1ed8-a158-e75153745e07@huawei.com> <20200724131059.GB6521@bogus> <00cf6e67-16ed-872d-2c16-0ceea6b6f514@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00cf6e67-16ed-872d-2c16-0ceea6b6f514@nvidia.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 26, 2020 at 05:16:27PM +0530, Sumit Gupta wrote: > > > > ERROR: modpost: "__cpu_logical_map" [drivers/cpufreq/tegra194-cpufreq.ko] undefined! > > > > > > > > ARM64 tegra194-cpufreq driver use cpu_logical_map, export > > > > __cpu_logical_map to fix build issue. > > > > > > > > I wonder why like other instances in the drivers, the mpidr is not get > > directly from the cpu. The cpufreq_driver->init call happens when the cpu > > is being brought online and is executed on the required cpu IIUC. > > > Yes, this occurs during hotplug case. > But in the case of system boot, 'cpufreq_driver->init' is called later > during cpufreq platform driver's probe. The value of CPU in 'policy->cpu' > can be different from the current CPU. That's why read_cpuid_mpidr() can't > be used. > Fair enough, why not do cross call like in set_target ? Since it is one-off in init, I don't see any issue when you are doing it runtime for set_target. > > read_cpuid_mpidr() is inline and avoids having to export the logical_cpu_map. > > Though we may not add physical hotplug anytime soon, less dependency > > on this cpu_logical_map is better given that we can resolve this without > > the need to access the map. > > To be honest, we have tried to remove all the dependency on cluster id in generic code as it is not well defined. This one is tegra specific driver so should be fine. But I am still bit nervous to export cpu_logical_map as we have no clue what that would mean for physical hotplug. -- Regards, Sudeep