Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f6493705 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/atomic, arch/m32r: Implement atomic_fetch_{add,sub,and,or,xor}() 



Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.

This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent cc102507

arch/m32r/include/asm/atomic.h

+34 −4
Original line number Diff line number Diff line
@@ -89,16 +89,46 @@ static __inline__ int atomic_##op##_return(int i, atomic_t *v) \ 
	return result;							\

}



#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)

#define ATOMIC_FETCH_OP(op)						\

static __inline__ int atomic_fetch_##op(int i, atomic_t *v)		\

{									\

	unsigned long flags;						\

	int result, val;						\

									\

	local_irq_save(flags);						\

	__asm__ __volatile__ (						\

		"# atomic_fetch_" #op "		\n\t"			\

		DCACHE_CLEAR("%0", "r4", "%2")				\

		M32R_LOCK" %1, @%2;		\n\t"			\

		"mv %0, %1			\n\t" 			\

		#op " %1, %3;			\n\t"			\

		M32R_UNLOCK" %1, @%2;		\n\t"			\

		: "=&r" (result), "=&r" (val)				\

		: "r" (&v->counter), "r" (i)				\

		: "memory"						\

		__ATOMIC_CLOBBER					\

	);								\

	local_irq_restore(flags);					\

									\

	return result;							\

}



#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)



ATOMIC_OPS(add)

ATOMIC_OPS(sub)



ATOMIC_OP(and)

ATOMIC_OP(or)

ATOMIC_OP(xor)

#undef ATOMIC_OPS

#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)



#define atomic_fetch_or atomic_fetch_or



ATOMIC_OPS(and)

ATOMIC_OPS(or)

ATOMIC_OPS(xor)



#undef ATOMIC_OPS

#undef ATOMIC_FETCH_OP

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP