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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 16A41C43381 for ; Thu, 28 Mar 2019 12:40:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D92722173C for ; Thu, 28 Mar 2019 12:40:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727930AbfC1MkH (ORCPT ); Thu, 28 Mar 2019 08:40:07 -0400 Received: from terminus.zytor.com ([198.137.202.136]:57161 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727123AbfC1MkD (ORCPT ); Thu, 28 Mar 2019 08:40:03 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x2SCdIvB3318890 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 28 Mar 2019 05:39:18 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x2SCdIqB3318887; Thu, 28 Mar 2019 05:39:18 -0700 Date: Thu, 28 Mar 2019 05:39:18 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Thomas Gleixner Message-ID: Cc: michael.h.kelley@microsoft.com, jkosina@suse.cz, linux-kernel@vger.kernel.org, luto@kernel.org, riel@surriel.com, kys@microsoft.com, mingo@kernel.org, mojha@codeaurora.org, Tianyu.Lan@microsoft.com, peterz@infradead.org, hpa@zytor.com, jpoimboe@redhat.com, tglx@linutronix.de, torvalds@linux-foundation.org, bp@alien8.de, konrad.wilk@oracle.com, gregkh@linuxfoundation.org Reply-To: mingo@kernel.org, mojha@codeaurora.org, michael.h.kelley@microsoft.com, linux-kernel@vger.kernel.org, jkosina@suse.cz, luto@kernel.org, riel@surriel.com, kys@microsoft.com, konrad.wilk@oracle.com, gregkh@linuxfoundation.org, peterz@infradead.org, Tianyu.Lan@microsoft.com, torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, jpoimboe@redhat.com, bp@alien8.de In-Reply-To: <20190326163811.598166056@linutronix.de> References: <20190326163811.598166056@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/urgent] x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y Git-Commit-ID: bebd024e4815b1a170fcd21ead9c2222b23ce9e6 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bebd024e4815b1a170fcd21ead9c2222b23ce9e6 Gitweb: https://git.kernel.org/tip/bebd024e4815b1a170fcd21ead9c2222b23ce9e6 Author: Thomas Gleixner AuthorDate: Tue, 26 Mar 2019 17:36:06 +0100 Committer: Thomas Gleixner CommitDate: Thu, 28 Mar 2019 13:34:58 +0100 x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y The SMT disable 'nosmt' command line argument is not working properly when CONFIG_HOTPLUG_CPU is disabled. The teardown of the sibling CPUs which are required to be brought up due to the MCE issues, cannot work. The CPUs are then kept in a half dead state. As the 'nosmt' functionality has become popular due to the speculative hardware vulnerabilities, the half torn down state is not a proper solution to the problem. Enforce CONFIG_HOTPLUG_CPU=y when SMP is enabled so the full operation is possible. Reported-by: Tianyu Lan Signed-off-by: Thomas Gleixner Acked-by: Greg Kroah-Hartman Cc: Konrad Wilk Cc: Josh Poimboeuf Cc: Mukesh Ojha Cc: Peter Zijlstra Cc: Jiri Kosina Cc: Rik van Riel Cc: Andy Lutomirski Cc: Micheal Kelley Cc: "K. Y. Srinivasan" Cc: Linus Torvalds Cc: Borislav Petkov Cc: K. Y. Srinivasan Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190326163811.598166056@linutronix.de --- arch/x86/Kconfig | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c1f9b3cf437c..5ad92419be19 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2217,14 +2217,8 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING If unsure, leave at the default value. config HOTPLUG_CPU - bool "Support for hot-pluggable CPUs" + def_bool y depends on SMP - ---help--- - Say Y here to allow turning CPUs off and on. CPUs can be - controlled through /sys/devices/system/cpu. - ( Note: power management support will enable this option - automatically on SMP systems. ) - Say N if you want to disable CPU hotplug. config BOOTPARAM_HOTPLUG_CPU0 bool "Set default setting of cpu0_hotpluggable"