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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 71229C2BC61 for ; Tue, 30 Oct 2018 19:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41B8C2080A for ; Tue, 30 Oct 2018 19:23:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41B8C2080A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.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 S1728234AbeJaERv (ORCPT ); Wed, 31 Oct 2018 00:17:51 -0400 Received: from mga11.intel.com ([192.55.52.93]:23900 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727346AbeJaERe (ORCPT ); Wed, 31 Oct 2018 00:17:34 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Oct 2018 12:22:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,445,1534834800"; d="scan'208";a="103876806" Received: from skl-02.jf.intel.com ([10.54.74.62]) by fmsmga001.fm.intel.com with ESMTP; 30 Oct 2018 12:22:48 -0700 From: Tim Chen To: Jiri Kosina , Thomas Gleixner Cc: Tim Chen , Tom Lendacky , Ingo Molnar , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , linux-kernel@vger.kernel.org, x86@kernel.org Subject: [Patch v4 16/18] x86/speculation: Enable STIBP to protect security sensitive tasks Date: Tue, 30 Oct 2018 11:49:23 -0700 Message-Id: <26ec186930a8fb33033743997bd56e5ce44050ec.1540923609.git.tim.c.chen@linux.intel.com> X-Mailer: git-send-email 2.9.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Enable STIBP defense on high security tasks. For normal tasks, STIBP is unused so they are not impacted by overhead from STIBP in lite protection mode. Signed-off-by: Tim Chen --- arch/x86/kernel/cpu/bugs.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 54f4675..b402b96 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -14,6 +14,8 @@ #include #include #include +#include +#include #include #include @@ -770,6 +772,37 @@ static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl) return 0; } +static void set_task_stibp(struct task_struct *tsk, bool stibp_on) +{ + bool update = false; + + if (!static_branch_unlikely(&spectre_v2_app_lite)) + return; + + if (stibp_on) + update = !test_and_set_tsk_thread_flag(tsk, TIF_STIBP); + else + update = test_and_clear_tsk_thread_flag(tsk, TIF_STIBP); + + if (!update) + return; + + if (tsk == current) + speculation_ctrl_update_current(); +} + +void arch_set_security(struct task_struct *tsk, unsigned int value) +{ + if (value > SECURITY_HIGH) + return; + + /* Update STIBP defenses */ + if (value == SECURITY_HIGH) + set_task_stibp(tsk, true); + else + set_task_stibp(tsk, false); +} + int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which, unsigned long ctrl) { -- 2.9.4