Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933404Ab2HVXme (ORCPT ); Wed, 22 Aug 2012 19:42:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47526 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756566Ab2HVXma (ORCPT ); Wed, 22 Aug 2012 19:42:30 -0400 Date: Wed, 22 Aug 2012 16:42:17 -0700 From: tip-bot for Borislav Petkov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, hpa@linux.intel.com, borislav.petkov@amd.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@linux.intel.com, borislav.petkov@amd.com In-Reply-To: <1344361461-10076-8-git-send-email-bp@amd64.org> References: <1344361461-10076-8-git-send-email-bp@amd64.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/microcode] x86, microcode, AMD: Check before applying a patch Git-Commit-ID: 685ca6d797af9d41164dd64dd60145d4946fc152 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-4.2.6 (terminus.zytor.com [127.0.0.1]); Wed, 22 Aug 2012 16:42:22 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2129 Lines: 60 Commit-ID: 685ca6d797af9d41164dd64dd60145d4946fc152 Gitweb: http://git.kernel.org/tip/685ca6d797af9d41164dd64dd60145d4946fc152 Author: Borislav Petkov AuthorDate: Wed, 20 Jun 2012 16:17:51 +0200 Committer: H. Peter Anvin CommitDate: Wed, 22 Aug 2012 16:15:41 -0700 x86, microcode, AMD: Check before applying a patch Make sure we're actually applying a microcode patch to a core which really needs it. This brings only a very very very minor slowdown on F10: 0.032218828 sec vs 0.056010626 sec with this patch. And small speedup on F15: 0.487089449 sec vs 0.180551162 sec (from perf output). Also, fixup comments while at it. Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1344361461-10076-8-git-send-email-bp@amd64.org Signed-off-by: H. Peter Anvin --- arch/x86/kernel/microcode_amd.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c index 9421338..8fdf7d9 100644 --- a/arch/x86/kernel/microcode_amd.c +++ b/arch/x86/kernel/microcode_amd.c @@ -202,11 +202,18 @@ static int apply_microcode_amd(int cpu) if (mc_amd == NULL) return 0; - wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code); - /* get patch id after patching */ rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); - /* check current patch id and patch's id for match */ + /* need to apply patch? */ + if (rev >= mc_amd->hdr.patch_id) { + c->microcode = rev; + return 0; + } + + wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code); + + /* verify patch application was successful */ + rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); if (rev != mc_amd->hdr.patch_id) { pr_err("CPU%d: update failed for patch_level=0x%08x\n", cpu, mc_amd->hdr.patch_id); -- 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/