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 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 58F2DC43441 for ; Wed, 28 Nov 2018 14:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FA542081B for ; Wed, 28 Nov 2018 14:35:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1FA542081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728775AbeK2Bgw (ORCPT ); Wed, 28 Nov 2018 20:36:52 -0500 Received: from terminus.zytor.com ([198.137.202.136]:44007 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728102AbeK2Bgv (ORCPT ); Wed, 28 Nov 2018 20:36:51 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wASEYEGr2324116 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 28 Nov 2018 06:34:14 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wASEYEwl2324113; Wed, 28 Nov 2018 06:34:14 -0800 Date: Wed, 28 Nov 2018 06:34:14 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Thomas Gleixner Message-ID: Cc: jkosina@suse.cz, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, longman9394@gmail.com, dwmw@amazon.co.uk, luto@kernel.org, ak@linux.intel.com, gregkh@linuxfoundation.org, thomas.lendacky@amd.com, david.c.stewart@intel.com, torvalds@linux-foundation.org, dave.hansen@intel.com, arjan@linux.intel.com, jpoimboe@redhat.com, mingo@kernel.org, peterz@infradead.org, asit.k.mallick@intel.com, keescook@chromium.org, casey.schaufler@intel.com, tim.c.chen@linux.intel.com, aarcange@redhat.com, jcm@redhat.com Reply-To: casey.schaufler@intel.com, keescook@chromium.org, aarcange@redhat.com, jcm@redhat.com, tim.c.chen@linux.intel.com, dave.hansen@intel.com, asit.k.mallick@intel.com, peterz@infradead.org, mingo@kernel.org, arjan@linux.intel.com, jpoimboe@redhat.com, luto@kernel.org, dwmw@amazon.co.uk, longman9394@gmail.com, torvalds@linux-foundation.org, david.c.stewart@intel.com, gregkh@linuxfoundation.org, thomas.lendacky@amd.com, ak@linux.intel.com, jkosina@suse.cz, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de In-Reply-To: <20181125185005.759457117@linutronix.de> References: <20181125185005.759457117@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/speculation: Prepare arch_smt_update() for PRCTL mode Git-Commit-ID: 6893a959d7fdebbab5f5aa112c277d5a44435ba1 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: 6893a959d7fdebbab5f5aa112c277d5a44435ba1 Gitweb: https://git.kernel.org/tip/6893a959d7fdebbab5f5aa112c277d5a44435ba1 Author: Thomas Gleixner AuthorDate: Sun, 25 Nov 2018 19:33:52 +0100 Committer: Thomas Gleixner CommitDate: Wed, 28 Nov 2018 11:57:13 +0100 x86/speculation: Prepare arch_smt_update() for PRCTL mode The upcoming fine grained per task STIBP control needs to be updated on CPU hotplug as well. Split out the code which controls the strict mode so the prctl control code can be added later. Mark the SMP function call argument __unused while at it. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jiri Kosina Cc: Tom Lendacky Cc: Josh Poimboeuf Cc: Andrea Arcangeli Cc: David Woodhouse Cc: Tim Chen Cc: Andi Kleen Cc: Dave Hansen Cc: Casey Schaufler Cc: Asit Mallick Cc: Arjan van de Ven Cc: Jon Masters Cc: Waiman Long Cc: Greg KH Cc: Dave Stewart Cc: Kees Cook Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185005.759457117@linutronix.de --- arch/x86/kernel/cpu/bugs.c | 46 +++++++++++++++++++++++++--------------------- 1 file changed, 25 insertions(+), 21 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 29f40a92f5a8..9cab538e10f1 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -530,40 +530,44 @@ specv2_set_mode: arch_smt_update(); } -static bool stibp_needed(void) +static void update_stibp_msr(void * __unused) { - /* Enhanced IBRS makes using STIBP unnecessary. */ - if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) - return false; - - /* Check for strict user mitigation mode */ - return spectre_v2_user == SPECTRE_V2_USER_STRICT; + wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); } -static void update_stibp_msr(void *info) +/* Update x86_spec_ctrl_base in case SMT state changed. */ +static void update_stibp_strict(void) { - wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); + u64 mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; + + if (sched_smt_active()) + mask |= SPEC_CTRL_STIBP; + + if (mask == x86_spec_ctrl_base) + return; + + pr_info("Update user space SMT mitigation: STIBP %s\n", + mask & SPEC_CTRL_STIBP ? "always-on" : "off"); + x86_spec_ctrl_base = mask; + on_each_cpu(update_stibp_msr, NULL, 1); } void arch_smt_update(void) { - u64 mask; - - if (!stibp_needed()) + /* Enhanced IBRS implies STIBP. No update required. */ + if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) return; mutex_lock(&spec_ctrl_mutex); - mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; - if (sched_smt_active()) - mask |= SPEC_CTRL_STIBP; - - if (mask != x86_spec_ctrl_base) { - pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n", - mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling"); - x86_spec_ctrl_base = mask; - on_each_cpu(update_stibp_msr, NULL, 1); + switch (spectre_v2_user) { + case SPECTRE_V2_USER_NONE: + break; + case SPECTRE_V2_USER_STRICT: + update_stibp_strict(); + break; } + mutex_unlock(&spec_ctrl_mutex); }