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Unverified Commit 8d235b17 authored by Andrea Parri's avatar Andrea Parri Committed by Palmer Dabbelt
Browse files

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: default avatarAndrea Parri <parri.andrea@gmail.com>
Signed-off-by: default avatarPalmer Dabbelt <palmer@sifive.com>
parent 0adb3285

arch/riscv/include/asm/barrier.h

+15 −0
Original line number Diff line number Diff line
@@ -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