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Subject[PATCH] riscv/barrier: Define __smp_{store_release,load_acquire}
Date
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 <parri.andrea@gmail.com>
---
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 5510366d169ae..d4628e4b3a5ea 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
--
2.7.4
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