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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 8A048C10F14 for ; Thu, 3 Oct 2019 16:16:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4919121783 for ; Thu, 3 Oct 2019 16:16:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119383; bh=E+8DDLBbjMszKWIYzvh2j4yfRBKcj4KQ5wwXpznjhCo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=iClC7AdZyvmYLvkmGezHSyHd5j3LtsuK931gQgCoYmF57FAnyl6kz95us1zqbPXIj 7pw+TtWjNFrnFTKZCTrazuMYeTXphj+OdEgqQ75sGQsv08dn7suBG70Izul9FU3m3m SeRUyrSVsJCJqT5NRUqFzFQAsgpNIGH5YR9qQ4Y4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388972AbfJCQQW (ORCPT ); Thu, 3 Oct 2019 12:16:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:41130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732434AbfJCQQQ (ORCPT ); Thu, 3 Oct 2019 12:16:16 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5F802133F; Thu, 3 Oct 2019 16:16:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119376; bh=E+8DDLBbjMszKWIYzvh2j4yfRBKcj4KQ5wwXpznjhCo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uQdfMJr0wCK7i5qVaJu8q6Dj5MRrC3Rs5GftIgfdYWkL6bs7I140J9gzrU85kYMme IGIufBi3aldGZAYalOh2pJAYAgOA/X/Tof8sykgWQGBlpwR9d2pt64lVxpbNJqxKil w74OXrj3YwoS1iubOusfkuhtfpdswKscEN6XKklI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 4.19 043/211] x86/apic: Soft disable APIC before initializing it Date: Thu, 3 Oct 2019 17:51:49 +0200 Message-Id: <20191003154457.710618197@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154447.010950442@linuxfoundation.org> References: <20191003154447.010950442@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner [ Upstream commit 2640da4cccf5cc613bf26f0998b9e340f4b5f69c ] If the APIC was already enabled on entry of setup_local_APIC() then disabling it soft via the SPIV register makes a lot of sense. That masks all LVT entries and brings it into a well defined state. Otherwise previously enabled LVTs which are not touched in the setup function stay unmasked and might surprise the just booting kernel. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20190722105219.068290579@linutronix.de Signed-off-by: Sasha Levin --- arch/x86/kernel/apic/apic.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 9bfbe1fa0339c..dfdd1caf0d55d 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1538,6 +1538,14 @@ static void setup_local_APIC(void) return; } + /* + * If this comes from kexec/kcrash the APIC might be enabled in + * SPIV. Soft disable it before doing further initialization. + */ + value = apic_read(APIC_SPIV); + value &= ~APIC_SPIV_APIC_ENABLED; + apic_write(APIC_SPIV, value); + #ifdef CONFIG_X86_32 /* Pound the ESR really hard over the head with a big hammer - mbligh */ if (lapic_is_integrated() && apic->disable_esr) { -- 2.20.1