From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752156AbaBMPyp (ORCPT ); Thu, 13 Feb 2014 10:54:45 -0500 Received: from terminus.zytor.com ([198.137.202.10]:40289 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752014AbaBMPyl (ORCPT ); Thu, 13 Feb 2014 10:54:41 -0500 Date: Thu, 13 Feb 2014 07:54:28 -0800 From: "tip-bot for H. Peter Anvin" Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, fengguang.wu@intel.com, hpa@linux.intel.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@linux.intel.com, fengguang.wu@intel.com In-Reply-To: <20140213124550.GA30497@localhost> References: <20140213124550.GA30497@localhost> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86, smap: Don' t enable SMAP if CONFIG_X86_SMAP is disabled Git-Commit-ID: 03bbd596ac04fef47ce93a730b8f086d797c3021 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 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Thu, 13 Feb 2014 07:54:34 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 03bbd596ac04fef47ce93a730b8f086d797c3021 Gitweb: http://git.kernel.org/tip/03bbd596ac04fef47ce93a730b8f086d797c3021 Author: H. Peter Anvin AuthorDate: Thu, 13 Feb 2014 07:34:30 -0800 Committer: H. Peter Anvin CommitDate: Thu, 13 Feb 2014 07:50:25 -0800 x86, smap: Don't enable SMAP if CONFIG_X86_SMAP is disabled If SMAP support is not compiled into the kernel, don't enable SMAP in CR4 -- in fact, we should clear it, because the kernel doesn't contain the proper STAC/CLAC instructions for SMAP support. Found by Fengguang Wu's test system. Reported-by: Fengguang Wu Link: http://lkml.kernel.org/r/20140213124550.GA30497@localhost Signed-off-by: H. Peter Anvin Cc: # v3.7+ --- arch/x86/kernel/cpu/common.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 24b6fd1..8e28bf2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -284,8 +284,13 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c) raw_local_save_flags(eflags); BUG_ON(eflags & X86_EFLAGS_AC); - if (cpu_has(c, X86_FEATURE_SMAP)) + if (cpu_has(c, X86_FEATURE_SMAP)) { +#ifdef CONFIG_X86_SMAP set_in_cr4(X86_CR4_SMAP); +#else + clear_in_cr4(X86_CR4_SMAP); +#endif + } } /*