Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755711AbaBTXwb (ORCPT ); Thu, 20 Feb 2014 18:52:31 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:45766 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755608AbaBTXwT (ORCPT ); Thu, 20 Feb 2014 18:52:19 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fengguang Wu , "H. Peter Anvin" Subject: [PATCH 3.12 43/82] x86, smap: Dont enable SMAP if CONFIG_X86_SMAP is disabled Date: Thu, 20 Feb 2014 15:52:26 -0800 Message-Id: <20140220235020.762281188@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140220235019.483734207@linuxfoundation.org> References: <20140220235019.483734207@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: "H. Peter Anvin" commit 03bbd596ac04fef47ce93a730b8f086d797c3021 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/common.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -284,8 +284,13 @@ static __always_inline void setup_smap(s 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 + } } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/