From 71621525c3bf9ed2a73446ba505ad5b980b6b8bb Mon Sep 17 00:00:00 2001 From: Alexey Brodkin Date: Wed, 21 Feb 2018 12:58:00 +0300 Subject: [PATCH] arc: Fine-tune implementation of memory barriers We improve on 2 things: 1. Only ARC HS family has "dmb" instructions so do compile-time check for automatically defined macro __ARCHS__. Previous check for ARCv2 ISA was not good enough because ARC EM family is v2 ISA as well but still "dmb" instaruction is not supported in EM family. 2. Still if there's no dedicated instruction for memory barrier let's at least insert compile-time barrier to make sure compiler deosn't reorder critical memory operations. Signed-off-by: Alexey Brodkin --- arch/arc/include/asm/io.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h index a12303b..060cdf6 100644 --- a/arch/arc/include/asm/io.h +++ b/arch/arc/include/asm/io.h @@ -10,7 +10,7 @@ #include #include -#ifdef CONFIG_ISA_ARCV2 +#ifdef __ARCHS__ /* * ARCv2 based HS38 cores are in-order issue, but still weakly ordered @@ -42,12 +42,12 @@ #define mb() asm volatile("sync\n" : : : "memory") #endif -#ifdef CONFIG_ISA_ARCV2 +#ifdef __ARCHS__ #define __iormb() rmb() #define __iowmb() wmb() #else -#define __iormb() do { } while (0) -#define __iowmb() do { } while (0) +#define __iormb() asm volatile("" : : : "memory") +#define __iowmb() asm volatile("" : : : "memory") #endif static inline void sync(void)