Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756256AbaFRVfO (ORCPT ); Wed, 18 Jun 2014 17:35:14 -0400 Received: from mail-qc0-f179.google.com ([209.85.216.179]:56425 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756004AbaFRVfL (ORCPT ); Wed, 18 Jun 2014 17:35:11 -0400 Date: Wed, 18 Jun 2014 17:35:08 -0400 (EDT) From: Nicolas Pitre To: Kevin Hilman cc: Stephen Boyd , Taras Kondratiuk , Thomas Petazzoni , Russell King , Jason Cooper , Victor Kamensky , LKML , Ben Dooks , Olof Johansson , Linaro Networking , linux-arm-kernel Subject: Re: [PATCH] ARM: zImage: ensure header in LE format for BE8 kernels In-Reply-To: Message-ID: References: <1397147232-28516-1-git-send-email-taras.kondratiuk@linaro.org> <53A1D701.8060404@codeaurora.org> <53A1D8FE.6030404@codeaurora.org> User-Agent: Alpine 2.11 (LFD 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 18 Jun 2014, Kevin Hilman wrote: > On Wed, Jun 18, 2014 at 11:22 AM, Stephen Boyd wrote: > > On 06/18/14 11:21, Kevin Hilman wrote: > >> On Wed, Jun 18, 2014 at 11:14 AM, Stephen Boyd wrote: > >>> On 06/18/14 10:55, Kevin Hilman wrote: > >>>> All of that to say, with this patch applied, I need a new (and > >>>> reliable) way to determine the endianness of a kernel just by looking > >>>> at the zImage. Recommendations welcome. > >>> Assuming that you have the .config configured to be built into the > >>> kernel you could use extract-ikconfig > >>> > >>> $ ./scripts/extract-ikconfig zImage | grep CONFIG_CPU_ENDIAN_BE8 > >> Unfortunately, I can't rely on having that built in since I want the > >> boot tools to be as generic as possible. > >> > >> > > > > Yeah ok. Perhaps you can look for the 'setend be' instruction right > > after the magic values instead. > > Yeah, that works, as long as I can always assume that instruction will > be at the same offset (currently at 0x30). Well... then you also have to test for the Thumb2 variant. And that forces this instruction to always be there. If we're to "officialize" this, I'd much prefer we add another magic value like this: diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index c95feab6ce..413fd94b53 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -128,6 +128,7 @@ start: .word _magic_sig @ Magic numbers to help the loader .word _magic_start @ absolute load/run zImage address .word _magic_end @ zImage end address + .word 0x04030201 @ endianness flag THUMB( .thumb ) 1: > > Kevin > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/