From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752608AbbFYQpi (ORCPT ); Thu, 25 Jun 2015 12:45:38 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38416 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751987AbbFYQoa (ORCPT ); Thu, 25 Jun 2015 12:44:30 -0400 From: Borislav Petkov To: Ingo Molnar Cc: LKML Subject: [PATCH 07/19] x86/cpu/amd: Use the full 64-bit TSC to detect the 2.6.2 bug Date: Thu, 25 Jun 2015 18:44:01 +0200 Message-Id: <1435250653-30182-8-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.3.5 In-Reply-To: <1435250653-30182-1-git-send-email-bp@alien8.de> References: <1435250653-30182-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Lutomirski This code is timing 100k indirect calls, so the added overhead of counting the number of cycles elapsed as a 64-bit number should be insignificant. Drop the optimization of using a 32-bit count. Signed-off-by: Andy Lutomirski Cc: Denys Vlasenko Cc: Huang Rui Cc: John Stultz Cc: Len Brown Cc: Peter Zijlstra Cc: Ralf Baechle Cc: kvm ML Cc: x86-ml Link: http://lkml.kernel.org/r/d58f339a9c0dd8352b50d2f7a216f67ec2844f20.1434501121.git.luto@kernel.org Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/amd.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index dd3a4baffe50..a69710db6112 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -114,7 +114,7 @@ static void init_amd_k6(struct cpuinfo_x86 *c) const int K6_BUG_LOOP = 1000000; int n; void (*f_vide)(void); - unsigned long d, d2; + u64 d, d2; printk(KERN_INFO "AMD K6 stepping B detected - "); @@ -125,10 +125,10 @@ static void init_amd_k6(struct cpuinfo_x86 *c) n = K6_BUG_LOOP; f_vide = vide; - rdtscl(d); + d = native_read_tsc(); while (n--) f_vide(); - rdtscl(d2); + d2 = native_read_tsc(); d = d2-d; if (d > 20*K6_BUG_LOOP) -- 2.3.5