From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben.dooks@codethink.co.uk (Ben Dooks) Date: Wed, 13 Feb 2013 11:27:56 +0000 Subject: [PATCH 10/17] ARM: update atag-to-fdt code to be endian agnostic In-Reply-To: References: <1360365467-25056-1-git-send-email-ben.dooks@codethink.co.uk> <1360365467-25056-11-git-send-email-ben.dooks@codethink.co.uk> <20130209120525.GD17833@n2100.arm.linux.org.uk> <51194381.9030505@codethink.co.uk> Message-ID: <511B78BC.7000708@codethink.co.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 12/02/13 21:53, Nicolas Pitre wrote: > On Mon, 11 Feb 2013, Ben Dooks wrote: > >> On 09/02/13 12:05, Russell King - ARM Linux wrote: >>> On Fri, Feb 08, 2013 at 11:17:40PM +0000, Ben Dooks wrote: >>>> - if (atag->hdr.tag != ATAG_CORE || >>>> - (atag->hdr.size != tag_size(tag_core)&& >>>> - atag->hdr.size != 2)) >>>> + if (atag->hdr.tag != atag32_to_cpu(ATAG_CORE) || >>>> + (atag->hdr.size != atag32_to_cpu(tag_size(tag_core))&& >>>> + atag->hdr.size != atag32_to_cpu(2))) >>> >>> This is wrong. You're saying that "ATAG_CORE" is in LE32 format. It >>> isn't. It's in CPU endian format. If you want to do this kind of thing, >>> you also need to define cpu_to_atag32() macros as well, otherwise this >>> will cause sparse warnings. >>> >>>> - initrd_start = atag->u.initrd.start; >>>> - initrd_size = atag->u.initrd.size; >>>> + initrd_start = atag32_to_cpu(atag->u.initrd.start); >>>> + initrd_size = atag32_to_cpu(____atag->u.initrd.size); >>> >>> Where did those four underscores come from? Has this been built? >> >> I probably missed building this one. I've been mostly testing with DT >> based systems. > > Is this BE8 mode available on old systems? Or, will those BE8 > capable old systems have BE userland compiled for them? BE8 is for ARMv6 and ARMv7 form of big endian. ARMv5 is BE32. > Where I want to get to is: do we need to support BE8 mode for ATAG based > systems at all, given that most if not all the modern ones should be DT > based now? Making the ATAG code BE8 aware is looking to be quite > invasive for potentially no users at all. The change is only useful when using a BE8 compiled kernel with a boot loader environment that is LE. Even if the ATAGs do not need fixing up, then we have a issue with uboot checking the zImage magic. I have pushed the ATAGs issues to a new series as it is not necessary for the current work we are doing with highbank primarily. -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius