From df2433d15ef6d2c33296b69c73ca7820f7ffad57 Mon Sep 17 00:00:00 2001 From: Taylor R Campbell Date: Fri, 11 Feb 2022 21:09:44 +0000 Subject: [PATCH 13/49] atomic_loadstore(9): Use membar_acquire/release. --- sys/sys/atomic.h | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/sys/sys/atomic.h b/sys/sys/atomic.h index 76b8ed841d65..8b9690dd4745 100644 --- a/sys/sys/atomic.h +++ b/sys/sys/atomic.h @@ -454,18 +454,12 @@ void kcsan_atomic_store(volatile void *, const void *, int); __END_ATOMIC_LOAD(__al_val); \ }) -/* - * We want {loads}-before-{loads,stores}. It is tempting to use - * membar_enter, but that provides {stores}-before-{loads,stores}, - * which may not help. So we must use membar_sync, which does the - * slightly stronger {loads,stores}-before-{loads,stores}. - */ #define atomic_load_acquire(p) \ ({ \ const volatile __typeof__(*(p)) *__al_ptr = (p); \ __ATOMIC_PTR_CHECK(__al_ptr); \ __BEGIN_ATOMIC_LOAD(__al_ptr, __al_val); \ - membar_sync(); \ + membar_acquire(); \ __END_ATOMIC_LOAD(__al_val); \ }) @@ -482,7 +476,7 @@ void kcsan_atomic_store(volatile void *, const void *, int); volatile __typeof__(*(p)) *__as_ptr = (p); \ __typeof__(*(p)) __as_val = (v); \ __ATOMIC_PTR_CHECK(__as_ptr); \ - membar_exit(); \ + membar_release(); \ __DO_ATOMIC_STORE(__as_ptr, __as_val); \ })