From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764045AbXILDXx (ORCPT ); Tue, 11 Sep 2007 23:23:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758014AbXILDXp (ORCPT ); Tue, 11 Sep 2007 23:23:45 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:47456 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757543AbXILDXo (ORCPT ); Tue, 11 Sep 2007 23:23:44 -0400 Date: Tue, 11 Sep 2007 20:23:32 -0700 From: Andrew Morton To: "Huang, Ying" Cc: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [BUGFIX] x86_64: NX bit handling in change_page_attr Message-Id: <20070911202332.c539f1fe.akpm@linux-foundation.org> In-Reply-To: <1187328518.28497.6.camel@caritas-dev.intel.com> References: <1187328518.28497.6.camel@caritas-dev.intel.com> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 17 Aug 2007 13:28:38 +0800 "Huang, Ying" wrote: > This patch fixes a bug of change_page_attr/change_page_attr_addr on > Intel x86_64 CPU. After changing page attribute to be executable with > these functions, the page remains un-executable on Intel x86_64 > CPU. Because on Intel x86_64 CPU, only if the "NX" bits of all four > level page tables are cleared, the corresponding page is executable > (refer to section 4.13.2 of Intel 64 and IA-32 Architectures Software > Developer's Manual). So, the bug is fixed through clearing the "NX" > bit of PMD when splitting the huge PMD. > > Signed-off-by: Huang Ying > > --- > > Index: linux-2.6.23-rc2-mm2/arch/x86_64/mm/pageattr.c > =================================================================== > --- linux-2.6.23-rc2-mm2.orig/arch/x86_64/mm/pageattr.c 2007-08-17 12:50:25.000000000 +0800 > +++ linux-2.6.23-rc2-mm2/arch/x86_64/mm/pageattr.c 2007-08-17 12:50:48.000000000 +0800 > @@ -147,6 +147,7 @@ > split = split_large_page(address, prot, ref_prot2); > if (!split) > return -ENOMEM; > + pgprot_val(ref_prot2) &= ~_PAGE_NX; > set_pte(kpte, mk_pte(split, ref_prot2)); > kpte_page = split; > } What happened with this? Still valid?