Page faults occurring on RO pages with the CopyOnWrite flag set will be
handled by the page handler as follows:
- allocate new frame
- establish temporary mapping for new frame
- copy original page to new frame
- update entry for the page where the fault occurred:
- set physical frame address to the allocated frame
- clear CoW flag and set Present, RW flags
- return from the fault handler to resume execution at the instruction
that caused the fault
Any other page faults will still cause a kernel panic
This allows us to remove the allocFn argument from the vmm functions
which causes the compiler's escape analysis to sometimes incorectly flag
it as escaping to the heap.
