From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Sun, 14 Jul 2013 22:53:25 +0100 Subject: v3.10 - big endian core support In-Reply-To: <51DFEF75.8080600@codethink.co.uk> References: <20130712134726.0a909165@skate> <51DFEF75.8080600@codethink.co.uk> Message-ID: <20130714215325.GB7382@mudshark.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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". Will