From 598865c5f32d6e11e99f2aac07348e5fd17cdc03 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 31 Jan 2018 15:55:24 +0000 Subject: [PATCH] arm64: barrier: Implement smp_cond_load_relaxed We can provide an implementation of smp_cond_load_relaxed using READ_ONCE and __cmpwait_relaxed. Signed-off-by: Will Deacon --- arch/arm64/include/asm/barrier.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index f11518a..822a919 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -128,6 +128,19 @@ do { \ __u.__val; \ }) +#define smp_cond_load_relaxed(ptr, cond_expr) \ +({ \ + typeof(ptr) __PTR = (ptr); \ + typeof(*ptr) VAL; \ + for (;;) { \ + VAL = READ_ONCE(*__PTR); \ + if (cond_expr) \ + break; \ + __cmpwait_relaxed(__PTR, VAL); \ + } \ + VAL; \ +}) + #define smp_cond_load_acquire(ptr, cond_expr) \ ({ \ typeof(ptr) __PTR = (ptr); \ -- 2.7.4