From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759424AbXHQF2U (ORCPT ); Fri, 17 Aug 2007 01:28:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754468AbXHQF2L (ORCPT ); Fri, 17 Aug 2007 01:28:11 -0400 Received: from mga02.intel.com ([134.134.136.20]:19273 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753710AbXHQF2K (ORCPT ); Fri, 17 Aug 2007 01:28:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.19,273,1183359600"; d="scan'208";a="280187389" Subject: [BUGFIX] x86_64: NX bit handling in change_page_attr From: "Huang, Ying" To: Andi Kleen Cc: linux-kernel@vger.kernel.org Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Fri, 17 Aug 2007 13:28:38 +0800 Message-Id: <1187328518.28497.6.camel@caritas-dev.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.10.2 X-OriginalArrivalTime: 17 Aug 2007 05:28:07.0341 (UTC) FILETIME=[6470D5D0:01C7E08F] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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; }