[PATCH v2 06/27] locking/atomic: arm: add preprocessor symbols

Mark Rutland
2023-06-05T07:02:20Z

Some atomics can be implemented in several different ways, e.g.
FULL/ACQUIRE/RELEASE ordered atomics can be implemented in terms of
RELAXED atomics, and ACQUIRE/RELEASE/RELAXED can be implemented in terms
of FULL ordered atomics. Other atomics are optional, and don't exist in
some configurations (e.g. not all architectures implement the 128-bit
cmpxchg ops).

Subsequent patches will require that architectures define a preprocessor
symbol for any atomic (or ordering variant) which is optional. This will
make the fallback ifdeffery more robust, and simplify future changes.

Add the required definitions to arch/arm.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
---
arch/arm/include/asm/atomic.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index 9458d47ff209c..f0e3b01afa746 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -197,6 +197,16 @@ static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
return val; \
}

+#define arch_atomic_add_return arch_atomic_add_return
+#define arch_atomic_sub_return arch_atomic_sub_return
+#define arch_atomic_fetch_add arch_atomic_fetch_add
+#define arch_atomic_fetch_sub arch_atomic_fetch_sub
+
+#define arch_atomic_fetch_and arch_atomic_fetch_and
+#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
+#define arch_atomic_fetch_or arch_atomic_fetch_or
+#define arch_atomic_fetch_xor arch_atomic_fetch_xor
+
static inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
{
int ret;
@@ -212,8 +222,6 @@ static inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
}
#define arch_atomic_cmpxchg arch_atomic_cmpxchg

-#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
-
#endif /* __LINUX_ARM_ARCH__ */

#define ATOMIC_OPS(op, c_op, asm_op) \
--
2.30.2