How can I chroot into a filesystem with a different architechture?

Question

I'm trying to chroot into a Arch Linux ARM filesystem from x86_64.

I've seen that it's possible to do using static qemu by copying the binary into the chroot system:

cp /usr/bin/qemu-arm   archarm-chroot/usr/bin    

But depite this I always get the following error:

chroot: failed to run command ‘/bin/bash’: Exec format error

I know this means that the architechtures differ. Am I doing something wrong?

Answer 1

You cannot chroot into different architecture. By chrooting, you are executing the binaries (from the chroot) on your architecture. Executing ARM binaries on x86 (and x86_64 in that matter) would lead to "Exec format error".

If you want to run binaries from different architecture you will need an Emulation, Qemu is a good candidate for this, but you will need to learn how to use it. This would involve creating RootFS and compiling a kernel for ARM, you will need a toolchain for compiling ARM binaries (and kernel) perhaps. One thing is for sure: Forget the chroot method, you cannot run binaries compiled for ARM on x86 (x86_64).

Edit: After the small talk with @UrichDangel, I realized, it should be possible to enter the chroot environment with qemu-user programs (qemu-arm in this case). Chroot should be executing qemu-arm compiled for your host architecture, then the qemu-arm can execute your /bin/sh (compiled for arm)