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Commit 7bd99b40 authored by Will Deacon's avatar Will Deacon Committed by Catalin Marinas
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arm64: Kconfig: Enable LSE atomics by default 



Now that we're seeing CPUs shipping with LSE atomics, default them to
'on' in Kconfig. CPUs without the instructions will continue to use
LDXR/STXR-based sequences, but they will be placed out-of-line by the
compiler.

Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 159fd7b8

arch/arm64/Kconfig

+3 −1
Original line number Original line Diff line number Diff line
@@ -1051,6 +1051,7 @@ config ARM64_PAN 




config ARM64_LSE_ATOMICS

config ARM64_LSE_ATOMICS

	bool "Atomic instructions"

	bool "Atomic instructions"

	default y

	help

	help

	  As part of the Large System Extensions, ARMv8.1 introduces new

	  As part of the Large System Extensions, ARMv8.1 introduces new

	  atomic instructions that are designed specifically to scale in

	  atomic instructions that are designed specifically to scale in
@@ -1059,7 +1060,8 @@ config ARM64_LSE_ATOMICS 
	  Say Y here to make use of these instructions for the in-kernel

	  Say Y here to make use of these instructions for the in-kernel

	  atomic routines. This incurs a small overhead on CPUs that do

	  atomic routines. This incurs a small overhead on CPUs that do

	  not support these instructions and requires the kernel to be

	  not support these instructions and requires the kernel to be

	  built with binutils >= 2.25.

	  built with binutils >= 2.25 in order for the new instructions

	  to be used.





config ARM64_VHE

config ARM64_VHE

	bool "Enable support for Virtualization Host Extensions (VHE)"

	bool "Enable support for Virtualization Host Extensions (VHE)"