We map kernel pages into all addresses spages, so they can be marked as
global.  This allows hardware to avoid flushing the kernel mappings when
moving between address spaces.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[Palmer: commit text]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>