I am not sure why 096cecb95e disabled the stack protector and sanitizers
for all files, but this is not necessary.
Only the pre_init code needs to run without them, as that code runs
identity mapped.
We initialize the MMU by first setting up the page tables for the
kernel image and the initial kernel stack.
Then we jump to a identity mapped page which makes the newly created
kernel root page table active by setting `satp` and then jumps to
`init`.
