From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756670AbZKBSzx (ORCPT ); Mon, 2 Nov 2009 13:55:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932107AbZKBSzw (ORCPT ); Mon, 2 Nov 2009 13:55:52 -0500 Received: from hera.kernel.org ([140.211.167.34]:43992 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756618AbZKBSzv (ORCPT ); Mon, 2 Nov 2009 13:55:51 -0500 Date: Mon, 2 Nov 2009 18:55:06 GMT From: tip-bot for Suresh Siddha Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, rostedt@goodmis.org, suresh.b.siddha@intel.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, suresh.b.siddha@intel.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091029024821.164525222@sbs-t61.sc.intel.com> References: <20091029024821.164525222@sbs-t61.sc.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86_64, cpa: Use only text section in set_kernel_text_rw/ro Message-ID: Git-Commit-ID: e7d23dde9b7ebb575e2bcee2abefc9ec1e4adde9 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e7d23dde9b7ebb575e2bcee2abefc9ec1e4adde9 Gitweb: http://git.kernel.org/tip/e7d23dde9b7ebb575e2bcee2abefc9ec1e4adde9 Author: Suresh Siddha AuthorDate: Wed, 28 Oct 2009 18:46:58 -0800 Committer: Ingo Molnar CommitDate: Mon, 2 Nov 2009 17:17:24 +0100 x86_64, cpa: Use only text section in set_kernel_text_rw/ro set_kernel_text_rw()/set_kernel_text_ro() are marking pages starting from _text to __start_rodata as RW or RO. With CONFIG_DEBUG_RODATA, there might be free pages (associated with padding the sections to 2MB large page boundary) between text and rodata sections that are given back to page allocator. So we should use only use the start (__text) and end (__stop___ex_table) of the text section in set_kernel_text_rw()/set_kernel_text_ro(). Signed-off-by: Suresh Siddha Acked-by: Steven Rostedt Tested-by: Steven Rostedt LKML-Reference: <20091029024821.164525222@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 4b507c0..5198b9b 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -700,7 +700,7 @@ int kernel_set_to_readonly; void set_kernel_text_rw(void) { unsigned long start = PFN_ALIGN(_text); - unsigned long end = PFN_ALIGN(__start_rodata); + unsigned long end = PFN_ALIGN(__stop___ex_table); if (!kernel_set_to_readonly) return; @@ -708,13 +708,18 @@ void set_kernel_text_rw(void) pr_debug("Set kernel text: %lx - %lx for read write\n", start, end); + /* + * Make the kernel identity mapping for text RW. Kernel text + * mapping will always be RO. Refer to the comment in + * static_protections() in pageattr.c + */ set_memory_rw(start, (end - start) >> PAGE_SHIFT); } void set_kernel_text_ro(void) { unsigned long start = PFN_ALIGN(_text); - unsigned long end = PFN_ALIGN(__start_rodata); + unsigned long end = PFN_ALIGN(__stop___ex_table); if (!kernel_set_to_readonly) return; @@ -722,6 +727,9 @@ void set_kernel_text_ro(void) pr_debug("Set kernel text: %lx - %lx for read only\n", start, end); + /* + * Set the kernel identity mapping for text RO. + */ set_memory_ro(start, (end - start) >> PAGE_SHIFT); }