[PATCH 4.14 024/195] [Variant 3/Meltdown] arm64: mm: Temporarily disable ARM64_SW_TTBR0_PAN

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 12:51:50 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@xxxxxxx>


Commit 376133b7edc2 upstream.

We're about to rework the way ASIDs are allocated, switch_mm is
implemented and low-level kernel entry/exit is handled, so keep the
ARM64_SW_TTBR0_PAN code out of the way whilst we do the heavy lifting.

It will be re-enabled in a subsequent patch.

Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Laura Abbott <labbott@xxxxxxxxxx>
Tested-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 1 +
1 file changed, 1 insertion(+)

--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -882,6 +882,7 @@ endif

config ARM64_SW_TTBR0_PAN
bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
+ depends on BROKEN # Temporary while switch_mm is reworked
help
Enabling this option prevents the kernel from accessing
user-space memory directly by pointing TTBR0_EL1 to a reserved