Commit 383499f8 authored by Dave Martin's avatar Dave Martin Committed by Catalin Marinas
Browse files

arm64: BTI: Add Kconfig entry for userspace BTI 



Now that the code for userspace BTI support is in the kernel add the
Kconfig entry so that it can be built and used.

[Split out of "arm64: Basic Branch Target Identification support"
    -- broonie]

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarDave Martin <Dave.Martin@arm.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 424037b7

arch/arm64/Kconfig

+22 −0
Original line number Diff line number Diff line
@@ -1522,6 +1522,28 @@ endmenu 


menu "ARMv8.5 architectural features"



config ARM64_BTI

	bool "Branch Target Identification support"

	default y

	help

	  Branch Target Identification (part of the ARMv8.5 Extensions)

	  provides a mechanism to limit the set of locations to which computed

	  branch instructions such as BR or BLR can jump.



	  To make use of BTI on CPUs that support it, say Y.



	  BTI is intended to provide complementary protection to other control

	  flow integrity protection mechanisms, such as the Pointer

	  authentication mechanism provided as part of the ARMv8.3 Extensions.

	  For this reason, it does not make sense to enable this option without

	  also enabling support for pointer authentication.  Thus, when

	  enabling this option you should also select ARM64_PTR_AUTH=y.



	  Userspace binaries must also be specifically compiled to make use of

	  this mechanism.  If you say N here or the hardware does not support

	  BTI, such binaries can still run, but you get no additional

	  enforcement of branch destinations.



config ARM64_E0PD

	bool "Enable support for E0PD"

	default y

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