arm64: avoid TLB conflict with CONFIG_RANDOMIZE_BASE

When CONFIG_RANDOMIZE_BASE is selected, we modify the page tables to remap the
kernel at a newly-chosen VA range. We do this with the MMU disabled, but do not
invalidate TLBs prior to re-enabling the MMU with the new tables. Thus the old
mappings entries may still live in TLBs, and we risk violating
Break-Before-Make requirements, leading to TLB conflicts and/or other issues.

We invalidate TLBs when we uninsall the idmap in early setup code, but prior to
this we are subject to issues relating to the Break-Before-Make violation.

Avoid these issues by invalidating the TLBs before the new mappings can be
used by the hardware.

Fixes: f80fb3a3d508 ("arm64: add support for kernel ASLR")
Cc: <[email protected]> # 4.6+
Acked-by: Ard Biesheuvel <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>

0 files changed, 0 insertions, 0 deletions