From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031128AbbD1WNa (ORCPT ); Tue, 28 Apr 2015 18:13:30 -0400 Received: from mga01.intel.com ([192.55.52.88]:50186 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030444AbbD1WN1 (ORCPT ); Tue, 28 Apr 2015 18:13:27 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,666,1422950400"; d="scan'208";a="486889719" From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , x86@kernel.org, Borislav Petkov Subject: [PATCH] x86: improve algorithm in clflush_cache_range Date: Tue, 28 Apr 2015 16:13:12 -0600 Message-Id: <1430259192-18802-1-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 1.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: H. Peter Anvin Cc: Thomas Gleixner Cc: Ingo Molnar Cc: x86@kernel.org Cc: 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(); } -- 1.9.3