mmu in arm: how to map kernel code (bare metal)

Question

In the link script, the starting address is 0xffffffff00000000. I can then load my own bare metal kernel (for aarch64) in an arbitrary (physical) address and use relative addressing. So when I turn on MMU, how do I know memory won't be written at where kernel is loaded? I mean, if I loaded kernel at 0x01000000, and map physical memory from 0xffffffff00000000 to 0xffffffffffffffff, it seems to me I will still be running into problems if I combine relative with absolute addressing. And it seems like the only solution is to ensure the kernel is loaded always at the same physical address, and then to map that to 0xffffffff00000000... But somehow this beats the purpose of an MMU. Am I correct in my thinking?

Answer 1

Actually the realization that ADR instruction on Aarch64 returns physical address helped me achieve what I wanted. I hope I am right in my thinking, though:

ADR x0, label  # here we get physical address of label to x0
LDR x0, =label # here we get start address from linker + label address to x0

So I don't really need to know the physical address (at which the kernel was loaded) at compile time to set a boundary around kernel to set MMU up properly.