From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755517AbZHORHa (ORCPT ); Sat, 15 Aug 2009 13:07:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755486AbZHORH3 (ORCPT ); Sat, 15 Aug 2009 13:07:29 -0400 Received: from hera.kernel.org ([140.211.167.34]:33707 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755480AbZHORH0 (ORCPT ); Sat, 15 Aug 2009 13:07:26 -0400 Date: Sat, 15 Aug 2009 17:06:52 GMT From: tip-bot for Borislav Petkov To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, kjwinchester@gmail.com, tglx@linutronix.de, mingo@elte.hu, borislav.petkov@amd.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, kjwinchester@gmail.com, tglx@linutronix.de, borislav.petkov@amd.com, mingo@elte.hu In-Reply-To: <1250251594-8348-2-git-send-email-borislav.petkov@amd.com> References: <1250251594-8348-2-git-send-email-borislav.petkov@amd.com> Subject: [tip:x86/urgent] x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit Message-ID: Git-Commit-ID: c74cb13b94118ec89e48849806356b67caa5ff86 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Sat, 15 Aug 2009 17:06:53 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: c74cb13b94118ec89e48849806356b67caa5ff86 Gitweb: http://git.kernel.org/tip/c74cb13b94118ec89e48849806356b67caa5ff86 Author: Borislav Petkov AuthorDate: Fri, 14 Aug 2009 14:06:34 +0200 Committer: Ingo Molnar CommitDate: Sat, 15 Aug 2009 18:43:59 +0200 x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit fbd8b1819e80ac5a176d085fdddc3a34d1499318 turns off the bit for /proc/cpuinfo. However, a proper/full fix would be to additionally turn off the bit in the CPUID output so that future callers get correct CPU features info. Do that by basically reversing what the BIOS wrongfully does at boot. Tested-by: Kevin Winchester Signed-off-by: Borislav Petkov Cc: kjwinchester@gmail.com Cc: mikpe@it.uu.se Cc: brgerst@gmail.com LKML-Reference: <1250251594-8348-2-git-send-email-borislav.petkov@amd.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/amd.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 63fddcd..0ee63dd 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -404,9 +404,19 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) /* * Some BIOSes incorrectly force this feature, but only K8 * revision D (model = 0x14) and later actually support it. + * (AMD Erratum #110, docId: 25759). */ - if (c->x86_model < 0x14) + if (c->x86_model < 0x14 && cpu_has(c, X86_FEATURE_LAHF_LM)) { + u64 val; + clear_cpu_cap(c, X86_FEATURE_LAHF_LM); + if (!rdmsrl_amd_safe(0xc001100d, &val)) { + val &= ~(1ULL << 32); + wrmsr_amd_safe(0xc001100d, (u32) val, + (u32)(val >> 32)); + } + } + } if (c->x86 == 0x10 || c->x86 == 0x11) set_cpu_cap(c, X86_FEATURE_REP_GOOD);