diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2016-07-01 18:25:31 +0100 |
|---|---|---|
| committer | Sami Tolvanen <samitolvanen@google.com> | 2016-09-29 10:52:56 -0700 |
| commit | 67cd3bda54dadba4f8892105adf9c2f3982bfa0a (patch) | |
| tree | b03a714f5d6f60f95b49e6bbe5276ccaa4d01b9b /arch/arm64 | |
| parent | 4dbc88bd2b6a74fd33483ee2593dcf2bd858eabe (diff) | |
FROMLIST: arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN
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>
Change-Id: Id00a8ad4169d6eb6176c468d953436eb4ae887ae
(cherry picked from commit 6a2d7bad43474c48b68394d455b84a16b7d7dc3f)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/Kconfig | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index bf24d67a1ff1..488fed2d5e5e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -706,6 +706,14 @@ config SETEND_EMULATION If unsure, say Y endif +config ARM64_SW_TTBR0_PAN + bool "Emulate Priviledged 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 |