Installable ARMv8 cross-toolchain

[Marek Vasut]

Dear Wookey,

> After a fair amount of dicking about I have managed to build a
> cross-toolchain for arm64/aarch64 which installs on Ubuntu Quantal. It
> even builds packages, although it has at least one notable limitation,
> and I have no idea if it produces working code yet :-)
> 
> The main limitation is that the default library search paths have come
> out as the old dpkg-cross ones, not the new multiarch ones. If someone
> can tell me where to fix that it would be very helpful and I'll try
> and put an updated one in the repo.
> 
> In the meantime you can work round it effectively using
> /etc/dpkg/buildflags. (see wiki page below for details)
> 
> The cross-toolchain only supports C, C++ and fortran with no extras
> like libssp, libmudflap etc, because there is no architecture support
> for them yet.
> 
> I started a port page to keep track of things here:
> http://wiki.debian.org/Arm64Port
> 
> And if you want to set up a quantal chroot and see if you can build
> things, details are here:
> https://wiki.linaro.org/Platform/DevPlatform/CrossCompile/arm64bootstrap
> 
> The bottom line is that you can debootstrap (or sbuild-createchroot) a
> quantal chroot, add the bootstrap repo and do 'apt-get install
> crossbuild-essential-arm64' and get a working cross-build environment.
> 
> The repo is here:
> http://people.debian.org/~wookey/bootstrap.html
> 
> That should be useable for both dpkg-cross style bulding or
> multiarch-style bulding.
> 
> The repo also contains updated dpkg-cross, multiarch python, multiarch
> perl, updated dpkg with buildprofile/staging support, sbuild (although
> in fact I think stock sbuild should work OK), and dose-builddebcheck
> which can tell you what things are currently cross-buildable from
> available binaries and sources. Most of that is pretty new and not
> very well tested but 'it works for me'.
> 
> More arm64 packages will be along soon (dose3 currently indicates 40
> more buildabale packages), but there is plenty still to fix for a full
> debootstrap-able arm64 package set.
> 
> Anyone keen to help with bootstrapping the port is very welcome. There
> will be a session about it at UDS next week, and a more general one on
> distro bootrapping at the Armv8 minisummit a the co-located linaro
> connect. And I'll be giving a talk about this stuff at Linxconf-Europe
> in Barcelona the week after.
> 
> I think that's all for now. Enjoy, and tell me what breaks :-)

I need to catch up with you in there ;-) What do you use for a bootloader on 
these armv8 devices?

> Wookey

Best regards,
Marek Vasut