From patchwork Mon Sep 21 10:37:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Borislav Petkov X-Patchwork-Id: 11789241 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 670E41731 for ; Mon, 21 Sep 2020 10:37:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49353218AC for ; Mon, 21 Sep 2020 10:37:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="T9CXOlxo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726483AbgIUKhy (ORCPT ); Mon, 21 Sep 2020 06:37:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726436AbgIUKhv (ORCPT ); Mon, 21 Sep 2020 06:37:51 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 315C7C061755; Mon, 21 Sep 2020 03:37:51 -0700 (PDT) Received: from zn.tnic (p200300ec2f07e300a1766583a478f392.dip0.t-ipconnect.de [IPv6:2003:ec:2f07:e300:a176:6583:a478:f392]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id D80851EC03C9; Mon, 21 Sep 2020 12:37:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1600684667; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=in/bybOnAIhAdt8FQ8tWtig4T4/V4JAt7w3WooCITpM=; b=T9CXOlxoQCHIOVk3J5RboDd29f68vxB/C2aSm2tOFNyC5MonwkiSZ0E4BWcGMgIUTpaop7 QnG30Ps/uMuZ/e+7qsWAbMS0UD3lNJQgAoEU9YNjR2Wlk5JdKJ9PFH9ihrj0lhM0Wr6QUi OHqh4RDlxnPsDC1FYlUrAD7doxbHcjc= Date: Mon, 21 Sep 2020 12:37:41 +0200 From: Borislav Petkov To: Sven Joachim Cc: Peter Zijlstra , rjw@rjwysocki.net, x86@kernel.org, tony.luck@intel.com, lenb@kernel.org, daniel.lezcano@linaro.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, ulf.hansson@linaro.org, paulmck@kernel.org, tglx@linutronix.de, naresh.kamboju@linaro.org, Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu@vger.kernel.org Subject: [PATCH] rcu/tree: Export rcu_idle_{enter,exit} to module Message-ID: <20200921103741.GC5901@zn.tnic> References: <20200915103157.345404192@infradead.org> <20200915103806.479637218@infradead.org> <87wo0npk72.fsf@turtle.gmx.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87wo0npk72.fsf@turtle.gmx.de> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Lemme add whatever get_maintainer spits, to Cc. On Mon, Sep 21, 2020 at 11:12:33AM +0200, Sven Joachim wrote: > On 2020-09-15 12:32 +0200, Peter Zijlstra wrote: > > > The C3 BusMaster idle code takes lock in a number of places, some deep > > inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have > > the driver take over RCU-idle duty and avoid flipping RCU state back > > and forth a lot. > > > > ( by marking 'C3 && bm_check' as RCU_IDLE, we _must_ call enter_bm() for > > that combination, otherwise we'll loose RCU-idle, this requires > > shuffling some code around ) > > > > Signed-off-by: Peter Zijlstra (Intel) > > I got modpost errors in 5.9-rc6 after this patch: > > ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! > ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! > > Reverting commit 1fecfdbb7acc made them go away. Notably my > configuration had CONFIG_ACPI_PROCESSOR=m, changing that > to CONFIG_ACPI_PROCESSOR=y let the build succeed as well. I guess this. Running randconfigs on it for a while, to see what else breaks. Reviewed-by: Paul E. McKenney --- From: Borislav Petkov Date: Mon, 21 Sep 2020 12:31:36 +0200 Fix this link error: ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light of ARM needing those soon too, they should simply be exported. Fixes: 1fecfdbb7acc ("ACPI: processor: Take over RCU-idle for C3-BM idle") Reported-by: Sven Joachim Suggested-by: Peter Zijlstra Signed-off-by: Borislav Petkov --- kernel/rcu/tree.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8ce77d9ac716..f78ee759af9c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -673,6 +673,7 @@ void rcu_idle_enter(void) lockdep_assert_irqs_disabled(); rcu_eqs_enter(false); } +EXPORT_SYMBOL_GPL(rcu_idle_enter); #ifdef CONFIG_NO_HZ_FULL /** @@ -886,6 +887,7 @@ void rcu_idle_exit(void) rcu_eqs_exit(false); local_irq_restore(flags); } +EXPORT_SYMBOL_GPL(rcu_idle_exit); #ifdef CONFIG_NO_HZ_FULL /**