From fd363bd417ddb6103564c69cfcbd92d9a7877431 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 24 Aug 2016 18:02:08 +0100 Subject: [PATCH] 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: # 4.6+ Acked-by: Ard Biesheuvel Acked-by: Will Deacon Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/kernel/head.S | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index b77f58355da1..3e7b050e99dc 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -757,6 +757,9 @@ ENTRY(__enable_mmu) isb bl __create_page_tables // recreate kernel mapping + tlbi vmalle1 // Remove any stale TLB entries + dsb nsh + msr sctlr_el1, x19 // re-enable the MMU isb ic iallu // flush instructions fetched -- 2.30.2