Commit ea7caffe authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Vineet Gupta
Browse files

ARC: atomics: Implement arch_atomic64_cmpxchg using _relaxed 



The core atomic code has a number of macros where it elaborates
architecture primitives into more functions. ARC uses
arch_atomic64_cmpxchg() as it's architecture primitive which disable alot
of the additional functions.

Instead provide arch_cmpxchg64_relaxed() as the primitive and rely on the
core macros to create arch_cmpxchg64().

The macros will also provide other functions, for instance,
try_cmpxchg64_release(), giving a more complete implementation.

Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/Z0747n5bSep4_1VX@J2N7QTR9R3


Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarVineet Gupta <vgupta@kernel.org>
parent 19272b37

arch/arc/include/asm/atomic64-arcv2.h

+5 −10
Original line number Diff line number Diff line
@@ -137,12 +137,9 @@ ATOMIC64_OPS(xor, xor, xor) 
#undef ATOMIC64_OP_RETURN

#undef ATOMIC64_OP



static inline s64

arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)

static inline u64 __arch_cmpxchg64_relaxed(volatile void *ptr, u64 old, u64 new)

{

	s64 prev;



	smp_mb();

	u64 prev;



	__asm__ __volatile__(

	"1:	llockd  %0, [%1]	\n"
@@ -152,14 +149,12 @@ arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new) 
	"	bnz     1b		\n"

	"2:				\n"

	: "=&r"(prev)

	: "r"(ptr), "ir"(expected), "r"(new)

	: "cc");	/* memory clobber comes from smp_mb() */



	smp_mb();

	: "r"(ptr), "ir"(old), "r"(new)

	: "memory", "cc");



	return prev;

}

#define arch_atomic64_cmpxchg arch_atomic64_cmpxchg

#define arch_cmpxchg64_relaxed __arch_cmpxchg64_relaxed



static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)

{