From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751386AbcIBFfu (ORCPT ); Fri, 2 Sep 2016 01:35:50 -0400 Received: from mail.skyhub.de ([78.46.96.112]:53643 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750873AbcIBFfs (ORCPT ); Fri, 2 Sep 2016 01:35:48 -0400 From: Borislav Petkov To: X86 ML Cc: LKML , Emanuel Czirai , Yaowu Xu Subject: [PATCH] x86/AMD: Apply erratum 665 on machines without a BIOS fix Date: Fri, 2 Sep 2016 07:35:50 +0200 Message-Id: <20160902053550.18097-1-bp@alien8.de> X-Mailer: git-send-email 2.8.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Emanuel Czirai 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 in that case. It is simple enough. Signed-off-by: Emanuel Czirai Cc: Yaowu Xu [ Write commit message. ] Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/amd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index f5c69d8974e1..eaf938e9df88 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -669,6 +669,14 @@ static void init_amd_gh(struct cpuinfo_x86 *c) set_cpu_bug(c, X86_BUG_AMD_TLB_MMATCH); } +static void init_amd_ln(struct cpuinfo_x86 *c) +{ +#define MSR_AMD64_DE_CFG 0xC0011029 + + /* Apply erratum 665 fix to machines without a BIOS fix. */ + msr_set_bit(MSR_AMD64_DE_CFG, 31); +} + static void init_amd_bd(struct cpuinfo_x86 *c) { u64 value; @@ -726,6 +734,7 @@ static void init_amd(struct cpuinfo_x86 *c) 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; } -- 2.8.4