Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932314AbbFQAlU (ORCPT ); Tue, 16 Jun 2015 20:41:20 -0400 Received: from mail.kernel.org ([198.145.29.136]:54230 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756115AbbFQAhB (ORCPT ); Tue, 16 Jun 2015 20:37:01 -0400 From: Andy Lutomirski To: x86@kernel.org Cc: Borislav Petkov , Peter Zijlstra , John Stultz , linux-kernel@vger.kernel.org, Len Brown , Huang Rui , Denys Vlasenko , kvm@vger.kernel.org, Ralf Baechle , Andy Lutomirski Subject: [PATCH v3 07/18] x86/cpu/amd: Use the full 64-bit TSC to detect the 2.6.2 bug Date: Tue, 16 Jun 2015 17:35:55 -0700 Message-Id: X-Mailer: git-send-email 2.4.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1261 Lines: 43 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 --- 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 5bd3a99dc20b..c5ceec532799 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -107,7 +107,7 @@ 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 - "); @@ -118,10 +118,10 @@ 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) -- 2.4.2 -- 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/