shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-07 19:30:30 +09:00
Code Issues Packages Projects Releases Wiki Activity

FROMLIST: arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN

Browse Source 
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>
This commit is contained in:
Catalin Marinas
2016-07-01 18:25:31 +01:00
committed by Sami Tolvanen
parent 4dbc88bd2b
commit 67cd3bda54
1 changed files with 8 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arm64/Kconfig
View File

@@ -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