[seL4] Userland components in Ring 1/2 (where kernel is in ring 0) to provide protection from less trusted components

Hey all,

I was wondering if it makes sense for someone building a system on seL4 to run certain drivers or other critical components in a more privileged environment, but still outside the kernel. Does using a different CPU mode in this context make sense? My hunch is that the case is no, because x86 has those extra rings, but ARM only has two modes, Supervisor/System and User mode, which would make it hard to provide any mechanism for the kernel to manage privileged components, because of the differences between platforms.