| Message ID | 1477675636-3957-9-git-send-email-catalin.marinas@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 969ef880d234..6b9a8446fc43 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -790,6 +790,14 @@ config SETEND_EMULATION If unsure, say Y endif +config ARM64_SW_TTBR0_PAN + bool "Emulate Privileged Access Never using TTBR0_EL1 switching" + help + Enabling this option prevents the kernel from accessing + user-space memory directly by pointing TTBR0_EL1 to a reserved + zeroed area and reserved ASID. The user access routines + restore the valid TTBR0_EL1 temporarily. + menu "ARMv8.1 architectural features" config ARM64_HW_AFDBM
This patch adds the Kconfig option to enable support for TTBR0 PAN emulation. The option is default off because of a slight performance hit when enabled, caused by the additional TTBR0_EL1 switching during user access operations or exception entry/exit code. Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+)