From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben.dooks@codethink.co.uk (Ben Dooks) Date: Mon, 15 Jul 2013 09:03:28 +0100 Subject: v3.10 - big endian core support In-Reply-To: <20130714215325.GB7382@mudshark.cambridge.arm.com> References: <20130712134726.0a909165@skate> <51DFEF75.8080600@codethink.co.uk> <20130714215325.GB7382@mudshark.cambridge.arm.com> Message-ID: <51E3ACD0.8040209@codethink.co.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 14/07/13 22:53, Will Deacon wrote: > On Fri, Jul 12, 2013 at 12:58:45PM +0100, Ben Dooks wrote: >> On 12/07/13 12:47, Thomas Petazzoni wrote: >>> Dear Vijay Kilari, >>> >>> On Fri, 12 Jul 2013 17:09:12 +0530, Vijay Kilari wrote: >>> >>>>> Ben Dooks has a separate branch on top of this base branch for >>>>> big-endian support, that adds atags compat code to convert the ATAGs >>>>> data from LE to BE. See the baserock/311/be/atags branch in >>>>> git://git.baserock.org/delta/linux. Or >>>>> http://git.baserock.org/cgi-bin/cgit.cgi/delta/linux.git/log/?h=baserock/311/be/atags. >>>> >>>> ARM VE TC2 board, enabling CONFIG_THUMB2_KERNEL failed to boot in BE mode >>>> It hangs at very early stage of boot >>> >>> Yeah, the Thumb2 code is not supported by Ben Dooks patches, it's part >>> of the TODO-list. I think Ben said he would probably not have much time >>> to work on this. I might be able to spare some time on this, so just >>> let me know if I should start working on this. If I remember correctly, >>> it's mainly the fixup_pv_table code that needed some Thumb2/BE love. >>> >>> Will, is getting Thumb2 working a requirement to get the BE support >>> merged, or can we for now make the BE option depends on !THUMB2_KERNEL ? >> >> I would like to sort out getting this code merged as it seems to have >> been tested by several people now outside Codethink. >> >> I could try doing the THUMB2 support, but I do not have a lot of >> experience with building THUMB2 kernels. > > I think we should try and get Thumb-2 supported before merging this as there > isn't any real reason why the instruction set should cause endianness > issues. We're also only almost at -rc1, so there's still time to fix this > properly for 3.12 instead of adding a fake Kconfig dependency. > > As for building a Thumb-2 kernel; just enable the option in menuconfig and > you're done. The compiler should "do the right thing". I can build it, I just don't have the time and hardware to give it a test at the moment. However it seems that changing to using 'rev16' instead of 'rev'. I will make the necessary changes and get this ready to go. -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius