[PATCH v3 03/10] arm64, kfence: enable KFENCE for ARM64

[Alexander Potapenko]

Will,

> Given that the pool is relatively small (i.e. when compared with our virtual
> address space), dedicating an area of virtual space sounds like it makes
> the most sense here. How early do you need it to be available?

How do we assign struct pages to a fixed virtual space area (I'm
currently experimenting with 0xffff7f0000000000-0xffff7f0000200000)?
Looks like filling page table entries (similarly to what's being done
in arch/arm64/mm/kasan_init.c) is not enough.
I thought maybe vmemmap_populate() would do the job, but it didn't
(virt_to_pfn() still returns invalid PFNs).