From 2be491b1dc8deae73befd10d137d485c1a41d7f1 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 16 Oct 2020 18:19:03 +0100 Subject: [PATCH] aarch64/arm: Add compiler barrier to barrier instructions When issuing barrier instructions like DSB or DMB, we must make sure that the compiler does not undermine out efforts to fence off instructions. Currently the compiler is free to move the barrier instruction around, in respect to former or later memory access statements, which is not what we want. Add a compiler barrier to the inline assembly statement in our DEFINE_SYSOP_TYPE_FUNC macro, to make sure memory accesses are not reordered by the compiler. This is in line with Linux' definition: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/include/asm/barrier.h Since those instructions share a definition, apart from DSB and DMB this now also covers some TLBI instructions. Having a compiler barrier there also is useful, although we probably have stronger barriers in place already. Change-Id: If6fe97b13a562643a643efc507cb4aad29daa5b6 Reported-by: Alexandru Elisei Signed-off-by: Andre Przywara --- include/arch/aarch32/arch_helpers.h | 2 +- include/arch/aarch64/arch_helpers.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/include/arch/aarch32/arch_helpers.h b/include/arch/aarch32/arch_helpers.h index 94cf7ea9d..82efb188a 100644 --- a/include/arch/aarch32/arch_helpers.h +++ b/include/arch/aarch32/arch_helpers.h @@ -166,7 +166,7 @@ static inline void _op(void) \ #define DEFINE_SYSOP_TYPE_FUNC(_op, _type) \ static inline void _op ## _type(void) \ { \ - __asm__ (#_op " " #_type); \ + __asm__ (#_op " " #_type : : : "memory"); \ } /* Define function for system instruction with register parameter */ diff --git a/include/arch/aarch64/arch_helpers.h b/include/arch/aarch64/arch_helpers.h index 1f2f4a923..5d1bc948c 100644 --- a/include/arch/aarch64/arch_helpers.h +++ b/include/arch/aarch64/arch_helpers.h @@ -80,7 +80,7 @@ static inline void _op(uint64_t v) \ #define DEFINE_SYSOP_TYPE_FUNC(_op, _type) \ static inline void _op ## _type(void) \ { \ - __asm__ (#_op " " #_type); \ + __asm__ (#_op " " #_type : : : "memory"); \ } /* Define function for system instruction with register parameter */