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Commit e898eb27 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/atomic, arch/metag: 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>
Acked-by: default avatarJames Hogan <james.hogan@imgtec.com>
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
Cc: linux-metag@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e39d88ea

arch/metag/include/asm/atomic.h

+2 −0
Original line number Diff line number Diff line
@@ -17,6 +17,8 @@ 
#include <asm/atomic_lnkget.h>

#endif



#define atomic_fetch_or atomic_fetch_or



#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)



#define atomic_dec_return(v) atomic_sub_return(1, (v))

arch/metag/include/asm/atomic_lnkget.h

+32 −4
Original line number Diff line number Diff line
@@ -69,16 +69,44 @@ 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)			\

{									\

	int result, temp;						\

									\

	smp_mb();							\

									\

	asm volatile (							\

		"1:	LNKGETD %1, [%2]\n"				\

		"	" #op "	%0, %1, %3\n"				\

		"	LNKSETD [%2], %0\n"				\

		"	DEFR	%0, TXSTAT\n"				\

		"	ANDT	%0, %0, #HI(0x3f000000)\n"		\

		"	CMPT	%0, #HI(0x02000000)\n"			\

		"	BNZ 1b\n"					\

		: "=&d" (temp), "=&d" (result)				\

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

		: "cc");						\

									\

	smp_mb();							\

									\

	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)



ATOMIC_OPS(and)

ATOMIC_OPS(or)

ATOMIC_OPS(xor)



#undef ATOMIC_OPS

#undef ATOMIC_FETCH_OP

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP

arch/metag/include/asm/atomic_lock1.h

+29 −4
Original line number Diff line number Diff line
@@ -64,15 +64,40 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ 
	return result;							\

}



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

#define ATOMIC_FETCH_OP(op, c_op)					\

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

{									\

	unsigned long result;						\

	unsigned long flags;						\

									\

	__global_lock1(flags);						\

	result = v->counter;						\

	fence();							\

	v->counter c_op i;						\

	__global_unlock1(flags);					\

									\

	return result;							\

}



#define ATOMIC_OPS(op, c_op)						\

	ATOMIC_OP(op, c_op)						\

	ATOMIC_OP_RETURN(op, c_op)					\

	ATOMIC_FETCH_OP(op, c_op)



ATOMIC_OPS(add, +=)

ATOMIC_OPS(sub, -=)

ATOMIC_OP(and, &=)

ATOMIC_OP(or, |=)

ATOMIC_OP(xor, ^=)



#undef ATOMIC_OPS

#define ATOMIC_OPS(op, c_op)						\

	ATOMIC_OP(op, c_op)						\

	ATOMIC_FETCH_OP(op, c_op)



ATOMIC_OPS(and, &=)

ATOMIC_OPS(or, |=)

ATOMIC_OPS(xor, ^=)



#undef ATOMIC_OPS

#undef ATOMIC_FETCH_OP

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP