This is a note to let you know that I've just added the patch titled
arm64: avoid TLB conflict with CONFIG_RANDOMIZE_BASE
to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-avoid-tlb-conflict-with-config_randomize_base.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fd363bd417ddb6103564c69cfcbd92d9a7877431 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@xxxxxxx>
Date: Wed, 24 Aug 2016 18:02:08 +0100
Subject: arm64: avoid TLB conflict with CONFIG_RANDOMIZE_BASE
From: Mark Rutland <mark.rutland@xxxxxxx>
commit fd363bd417ddb6103564c69cfcbd92d9a7877431 upstream.
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")
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/head.S | 3 +++
1 file changed, 3 insertions(+)
--- 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
Patches currently in stable-queue which might be from mark.rutland@xxxxxxx are
queue-4.7/arm64-kernel-avoid-literal-load-of-virtual-address-with-mmu-off.patch
queue-4.7/arm64-avoid-tlb-conflict-with-config_randomize_base.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html