. map kernel in non-user
. don't map in first pages of kernel code and data
if possible
these first pages could actually be freed but as the
kernel isn't allowed to touch them either we can't reuse
them until VM has totally taken over page table management
and kernel doesn't rely on identity mapping any more.
their own fully fledged virtual address space and freeing
their pre-allocated heap+stack area (necessary to let memory
driver map in arbitrary areas of memory for /dev/mem without
sys_vm_map)
- small optimization preallocating memory on exec
- finished VR_DIRECT physical mapping code
