From 6afdaf109c34acd9cbc85ef687e3e4e991e5fd89 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 5 Feb 2018 15:34:16 +0000 Subject: [PATCH] arm64: barrier: Add CSDB macros to control data-value prediction Commit 669474e772b9 upstream. For CPUs capable of data value prediction, CSDB waits for any outstanding predictions to architecturally resolve before allowing speculative execution to continue. Provide macros to expose it to the arch code. Reviewed-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/assembler.h | 7 +++++++ arch/arm64/include/asm/barrier.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index c8ec722..20f5845 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -96,6 +96,13 @@ .endm /* + * Value prediction barrier + */ + .macro csdb + hint #20 + .endm + +/* * NOP sequence */ .macro nops, num diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 0fe7e43..c68fdc5 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -31,6 +31,8 @@ #define dmb(opt) asm volatile("dmb " #opt : : : "memory") #define dsb(opt) asm volatile("dsb " #opt : : : "memory") +#define csdb() asm volatile("hint #20" : : : "memory") + #define mb() dsb(sy) #define rmb() dsb(ld) #define wmb() dsb(st) -- 2.7.4