Move address space virtual address range allocation to userspace
There's currently a lot of code in the kernel dealing solely with managing user address space virtual address allocation. A more minimal kernel would only store the grants and their ranges, which would (1) allow userspace to implement guard pages, (2) remove the need for mmap_min
, and (3) simplify mmap and similar operations, so that they always behave as MAP_FIXED_NOREPLACE
.