From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752484AbbFYQpV (ORCPT ); Thu, 25 Jun 2015 12:45:21 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38418 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752030AbbFYQob (ORCPT ); Thu, 25 Jun 2015 12:44:31 -0400 From: Borislav Petkov To: Ingo Molnar Cc: LKML Subject: [PATCH 06/19] x86/tsc: Use the full 64-bit TSC in delay_tsc() Date: Thu, 25 Jun 2015 18:44:00 +0200 Message-Id: <1435250653-30182-7-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 As a very minor optimization, delay_tsc() was only using the low 32 bits of the TSC. It's a delay function, so just use the whole thing. 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/bd1a277c71321b67c4794970cb5ace05efe21ab6.1434501121.git.luto@kernel.org Signed-off-by: Borislav Petkov --- arch/x86/lib/delay.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c index 9a52ad0c0758..35115f3786a9 100644 --- a/arch/x86/lib/delay.c +++ b/arch/x86/lib/delay.c @@ -49,16 +49,16 @@ static void delay_loop(unsigned long loops) /* TSC based delay: */ static void delay_tsc(unsigned long __loops) { - u32 bclock, now, loops = __loops; + u64 bclock, now, loops = __loops; int cpu; preempt_disable(); cpu = smp_processor_id(); rdtsc_barrier(); - rdtscl(bclock); + bclock = native_read_tsc(); for (;;) { rdtsc_barrier(); - rdtscl(now); + now = native_read_tsc(); if ((now - bclock) >= loops) break; @@ -80,7 +80,7 @@ static void delay_tsc(unsigned long __loops) loops -= (now - bclock); cpu = smp_processor_id(); rdtsc_barrier(); - rdtscl(bclock); + bclock = native_read_tsc(); } } preempt_enable(); -- 2.3.5