From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57205 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965747AbcIVRoe (ORCPT ); Thu, 22 Sep 2016 13:44:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Emanuel Czirai , Borislav Petkov , Yaowu Xu , Thomas Gleixner Subject: [PATCH 4.7 062/184] x86/AMD: Apply erratum 665 on machines without a BIOS fix Date: Thu, 22 Sep 2016 19:39:56 +0200 Message-Id: <20160922174051.364930078@linuxfoundation.org> In-Reply-To: <20160922174048.653794923@linuxfoundation.org> References: <20160922174048.653794923@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Emanuel Czirai commit d1992996753132e2dafe955cccb2fb0714d3cfc4 upstream. AMD F12h machines have an erratum which can cause DIV/IDIV to behave unpredictably. The workaround is to set MSRC001_1029[31] but sometimes there is no BIOS update containing that workaround so let's do it ourselves unconditionally. It is simple enough. [ Borislav: Wrote commit message. ] Signed-off-by: Emanuel Czirai Signed-off-by: Borislav Petkov Cc: Yaowu Xu Link: http://lkml.kernel.org/r/20160902053550.18097-1-bp@alien8.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -669,6 +669,17 @@ static void init_amd_gh(struct cpuinfo_x set_cpu_bug(c, X86_BUG_AMD_TLB_MMATCH); } +#define MSR_AMD64_DE_CFG 0xC0011029 + +static void init_amd_ln(struct cpuinfo_x86 *c) +{ + /* + * Apply erratum 665 fix unconditionally so machines without a BIOS + * fix work. + */ + msr_set_bit(MSR_AMD64_DE_CFG, 31); +} + static void init_amd_bd(struct cpuinfo_x86 *c) { u64 value; @@ -726,6 +737,7 @@ static void init_amd(struct cpuinfo_x86 case 6: init_amd_k7(c); break; case 0xf: init_amd_k8(c); break; case 0x10: init_amd_gh(c); break; + case 0x12: init_amd_ln(c); break; case 0x15: init_amd_bd(c); break; }