From 8d235b174af5d0af35ff206c15041fc2b02a0993 Mon Sep 17 00:00:00 2001 From: Andrea Parri Date: Tue, 27 Feb 2018 03:24:11 +0100 Subject: [PATCH] riscv/barrier: Define __smp_{store_release,load_acquire} Introduce __smp_{store_release,load_acquire}, and rely on the generic definitions for smp_{store_release,load_acquire}. This avoids the use of full ("rw,rw") fences on SMP. Signed-off-by: Andrea Parri Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/barrier.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/riscv/include/asm/barrier.h b/arch/riscv/include/asm/barrier.h index 5510366d169a..d4628e4b3a5e 100644 --- a/arch/riscv/include/asm/barrier.h +++ b/arch/riscv/include/asm/barrier.h @@ -38,6 +38,21 @@ #define __smp_rmb() RISCV_FENCE(r,r) #define __smp_wmb() RISCV_FENCE(w,w) +#define __smp_store_release(p, v) \ +do { \ + compiletime_assert_atomic_type(*p); \ + RISCV_FENCE(rw,w); \ + WRITE_ONCE(*p, v); \ +} while (0) + +#define __smp_load_acquire(p) \ +({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + compiletime_assert_atomic_type(*p); \ + RISCV_FENCE(r,rw); \ + ___p1; \ +}) + /* * This is a very specific barrier: it's currently only used in two places in * the kernel, both in the scheduler. See include/linux/spinlock.h for the two -- 2.30.2