From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Thu, 11 Feb 2016 18:00:32 +0000 Subject: [PATCH v2] ARM: mm: mark section-aligned portion of rodata NX In-Reply-To: References: <20151207223534.GA13722@www.outflux.net> Message-ID: <20160211180032.GY10826@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jan 22, 2016 at 01:19:03PM -0800, Kees Cook wrote: > On Tue, Dec 8, 2015 at 10:38 AM, Kees Cook wrote: > > On Mon, Dec 7, 2015 at 11:47 PM, Ard Biesheuvel > > wrote: > >> On 7 December 2015 at 23:35, Kees Cook wrote: > >>> /* > >>> + * Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will > >>> + * be the first section-aligned location after __start_rodata. Otherwise, > >>> + * it will be equal to __start_rodata. > >>> + */ > >>> +__start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT); ... I'm afraid this causes build errors on two configurations: ./arch/arm/kernel/vmlinux.lds:701: undefined symbol `SECTION_SHIFT' referenced in expression which I think is down to the new __start_rodata_section_aligned line. Olof's builder errored out with this for both allnoconfig and lpc18xx_defconfig builds. Both probably due to CONFIG_MMU being unset, and hence no definition for SECTION_SHIFT. I think you need to make this conditional on CONFIG_MMU. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently@9.6Mbps down 400kbps up according to speedtest.net.