address space on the amd64 architecture. The amd64 architecture
requires kernel code and global variables to reside in the highest 2GB
of the 64-bit virtual address space. Thus, KERNBASE cannot change.
However, KERNBASE is sometimes used as the start of the kernel virtual
address space. Henceforth, VM_MIN_KERNEL_ADDRESS should be used
instead. Since KERNBASE and VM_MIN_KERNEL_ADDRESS are still the same
address, there should be no visible effect from this change (yet).
That said, kris@ has tested crash dumps under the full patch that
increases the kernel virtual address space on amd64 to 6GB.
Tested by: kris@
948c5cc27e