+++ Wookey [2014-01-29 16:36 +0000]:
Someone asked if this worked, and I thought 'that's trivial to test with multiarch' so I did. On Saucy (where there is no multiarch version skew issue between binary versions of packages) the dpkg --add-architecutre armhf apt-get update apt-get install links:armhf part works very nicely. Everything installs as required.
However binaries don't run - they just get killed.
Turns out that our arm64 kernel config has: vm.mmap_min_addr=65536 but armhf binaries tend to get mmapped at 0x8000 (32K).
This has been fixed in the default kernel configs now.
part2: Once this is fixed
some binaries work (hello, bzip2) but fancier things still don't (links, wget). They segfault after loading libs. I'm still investigating that, but it looks like we have at least two issues..
So after rather a lot of faffing round related issues I got to the bottom of this problem which turned out to be 'kernel too old'. The Linaro Foundation 3.8 kernels I was using doesn't work in this regard. Changing to last month's release (and munging the kernel command line with the very cool kcmt utility works fine).
So, I've now uploaded A saucy armhf/arm64 configured multiarch image and tarball to: http://people.debian.org/~wookey/bootstrap/rootfs/
2G disk image: (as 92MB file) http://people.debian.org/~wookey/bootstrap/rootfs/saucy-arm64-multiarch.img.... Corresponding kernel: http://people.debian.org/~wookey/bootstrap/rootfs/linux-system-foundation.ax... tarball of same rootfs: http://people.debian.org/~wookey/bootstrap/rootfs/saucy-multiarch.tar.gz
All linked on https://wiki.debian.org/Arm64Port#Pre-built_Rootfses
Wookey