> the issue is that that 1/2/3G of kernel space is in a total of 4G of
> address space, and given the size of the kernel and the alignment
> requirements, things are a bit limited
the exact same limits apply to amd64 kernels as well.
> on amd64 you have much more address space to work with, so that 2G of
> kernel space can be moved to far more locations
you're wrong, the kernel image cannot be at arbitrary addresses, it *must* be in the top 2GB of the 64 bit virtual address space. i suggest you study the amd64 ABI and in particular -mcmodel=kernel.