Do you cross-compile from aarch64 or to aarch64?

I tend to treat the desire to cross-compile as a rather strong indicator that the architecture is just not viable for general-purpose computing. Either because it's impossible to get actual hardware at all, or the hardware doesn't have decent specs. In both cases, it's going to be difficult find a business justification for building for this architecture (again for general-purpose computing).

Obviously, architecture bringup is an exception, but we are way past that for aarch64.