From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753535AbaHKNay (ORCPT ); Mon, 11 Aug 2014 09:30:54 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:65375 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbaHKNax (ORCPT ); Mon, 11 Aug 2014 09:30:53 -0400 Date: Mon, 11 Aug 2014 14:30:55 +0100 From: Will Deacon To: Kees Cook Cc: "linux-kernel@vger.kernel.org" , Liu hua , "msalter@redhat.com" , Rabin Vincent , Nikolay Borisov , Nicolas Pitre , Leif Lindholm , Tomasz Figa , Rob Herring , Doug Anderson , Jason Wessel , Laura Abbott , Catalin Marinas , Russell King - ARM Linux , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 8/8] ARM: mm: allow text and rodata sections to be read-only Message-ID: <20140811133055.GA15853@arm.com> References: <1407423713-4160-1-git-send-email-keescook@chromium.org> <1407423713-4160-9-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1407423713-4160-9-git-send-email-keescook@chromium.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 07, 2014 at 04:01:53PM +0100, Kees Cook wrote: > This introduces CONFIG_DEBUG_RODATA, making kernel text and rodata > read-only. Additionally, this splits rodata from text so that rodata can > also be NX, which may lead to wasted memory when aligning to SECTION_SIZE. > The read-only areas are made writable during ftrace updates and kexec. [...] > diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c > index 1ac184f2bdd8..4423a565ef6f 100644 > --- a/arch/arm/kernel/machine_kexec.c > +++ b/arch/arm/kernel/machine_kexec.c > @@ -164,11 +164,11 @@ void machine_kexec(struct kimage *image) > reboot_code_buffer = page_address(image->control_code_page); > > /* Prepare parameters for reboot_code_buffer*/ > + set_kernel_text_rw(); > kexec_start_address = image->start; > kexec_indirection_page = page_list; > kexec_mach_type = machine_arch_type; > - kexec_boot_atags = dt_mem ?: image->start > - - KEXEC_ARM_ZIMAGE_OFFSET > + kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET > + KEXEC_ARM_ATAGS_OFFSET; Minor nit: but this patch and the kexec patch earlier in the series seem to move this line around in different ways without actually changing the code. I guess you just got a screwy rebase? Will From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 11 Aug 2014 14:30:55 +0100 Subject: [PATCH 8/8] ARM: mm: allow text and rodata sections to be read-only In-Reply-To: <1407423713-4160-9-git-send-email-keescook@chromium.org> References: <1407423713-4160-1-git-send-email-keescook@chromium.org> <1407423713-4160-9-git-send-email-keescook@chromium.org> Message-ID: <20140811133055.GA15853@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Aug 07, 2014 at 04:01:53PM +0100, Kees Cook wrote: > This introduces CONFIG_DEBUG_RODATA, making kernel text and rodata > read-only. Additionally, this splits rodata from text so that rodata can > also be NX, which may lead to wasted memory when aligning to SECTION_SIZE. > The read-only areas are made writable during ftrace updates and kexec. [...] > diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c > index 1ac184f2bdd8..4423a565ef6f 100644 > --- a/arch/arm/kernel/machine_kexec.c > +++ b/arch/arm/kernel/machine_kexec.c > @@ -164,11 +164,11 @@ void machine_kexec(struct kimage *image) > reboot_code_buffer = page_address(image->control_code_page); > > /* Prepare parameters for reboot_code_buffer*/ > + set_kernel_text_rw(); > kexec_start_address = image->start; > kexec_indirection_page = page_list; > kexec_mach_type = machine_arch_type; > - kexec_boot_atags = dt_mem ?: image->start > - - KEXEC_ARM_ZIMAGE_OFFSET > + kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET > + KEXEC_ARM_ATAGS_OFFSET; Minor nit: but this patch and the kexec patch earlier in the series seem to move this line around in different ways without actually changing the code. I guess you just got a screwy rebase? Will