From 7bd99b403405d329b9b72f6bae6a07c10bfa1b95 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 21 May 2018 19:14:22 +0100 Subject: [PATCH] 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: Mark Rutland Acked-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 4d98774cf3c7..3aed13626fd7 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1051,6 +1051,7 @@ config ARM64_PAN config ARM64_LSE_ATOMICS bool "Atomic instructions" + default y help As part of the Large System Extensions, ARMv8.1 introduces new 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 atomic routines. This incurs a small overhead on CPUs that do 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 bool "Enable support for Virtualization Host Extensions (VHE)" -- 2.45.2