From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753156AbbEKIRN (ORCPT ); Mon, 11 May 2015 04:17:13 -0400 Received: from mail.skyhub.de ([78.46.96.112]:55971 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752540AbbEKIQB (ORCPT ); Mon, 11 May 2015 04:16:01 -0400 From: Borislav Petkov To: Ingo Molnar Cc: LKML Subject: [PATCH 1/5] x86/mm: Do not flush last cacheline twice in clflush_cache_range() Date: Mon, 11 May 2015 10:15:49 +0200 Message-Id: <1431332153-18566-5-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.3.5 In-Reply-To: <1431332153-18566-1-git-send-email-bp@alien8.de> References: <1431332153-18566-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ross Zwisler The current algorithm used in clflush_cache_range() can cause the last cache line of the buffer to be flushed twice. Fix that algorithm so that each cache line will only be flushed once. Signed-off-by: Ross Zwisler Reported-by: H. Peter Anvin Cc: Thomas Gleixner Cc: Ingo Molnar Cc: x86-ml Link: http://lkml.kernel.org/r/1430259192-18802-1-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Borislav Petkov --- arch/x86/mm/pageattr.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 89af288ec674..338e507f95b8 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -129,16 +129,15 @@ within(unsigned long addr, unsigned long start, unsigned long end) */ void clflush_cache_range(void *vaddr, unsigned int size) { - void *vend = vaddr + size - 1; + unsigned long clflush_mask = boot_cpu_data.x86_clflush_size - 1; + char *vend = (char *)vaddr + size; + char *p; mb(); - for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size) - clflushopt(vaddr); - /* - * Flush any possible final partial cacheline: - */ - clflushopt(vend); + for (p = (char *)((unsigned long)vaddr & ~clflush_mask); + p < vend; p += boot_cpu_data.x86_clflush_size) + clflushopt(p); mb(); } -- 2.3.5