Commit fd363bd4 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas

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: f80fb3a3 ("arm64: add support for kernel ASLR")
Cc: <stable@vger.kernel.org> # 4.6+
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent fa8410b3
...@@ -757,6 +757,9 @@ ENTRY(__enable_mmu) ...@@ -757,6 +757,9 @@ ENTRY(__enable_mmu)
isb isb
bl __create_page_tables // recreate kernel mapping bl __create_page_tables // recreate kernel mapping
tlbi vmalle1 // Remove any stale TLB entries
dsb nsh
msr sctlr_el1, x19 // re-enable the MMU msr sctlr_el1, x19 // re-enable the MMU
isb isb
ic iallu // flush instructions fetched ic iallu // flush instructions fetched
......
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