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-rw-r--r--arch/arm64/Kconfig21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fa51ff0470c1..3d9cab156740 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -756,6 +756,27 @@ config ARM64_LSE_ATOMICS
endmenu
+config ARM64_UAO
+ bool "Enable support for User Access Override (UAO)"
+ default y
+ help
+ User Access Override (UAO; part of the ARMv8.2 Extensions)
+ causes the 'unprivileged' variant of the load/store instructions to
+ be overriden to be privileged.
+
+ This option changes get_user() and friends to use the 'unprivileged'
+ variant of the load/store instructions. This ensures that user-space
+ really did have access to the supplied memory. When addr_limit is
+ set to kernel memory the UAO bit will be set, allowing privileged
+ access to kernel memory.
+
+ Choosing this option will cause copy_to_user() et al to use user-space
+ memory permissions.
+
+ The feature is detected at runtime, the kernel will use the
+ regular load/store instructions if the cpu does not implement the
+ feature.
+
endmenu
menu "Boot options"