From:   Leonardo Bras <leobras@redhat.com>
To:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Leonardo Bras <leobras@redhat.com>, Guo Ren <guoren@kernel.org>
Cc:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH v2 4/6] riscv/cmpxchg: Deduplicate xchg() asm functions
Date:   Tue, 21 Mar 2023 03:34:30 -0300
Message-Id: <20230321063430.2218795-5-leobras@redhat.com>
In-Reply-To: <20230321063430.2218795-1-leobras@redhat.com>
References: <20230321063430.2218795-1-leobras@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In this header every xchg define (_relaxed, _acquire, _release, vanilla)
contain it's own asm file, both for 4-byte variables an 8-byte variables,
on a total of 8 versions of mostly the same asm.

This is usually bad, as it means any change may be done in up to 8
different places.

Unify those versions by creating a new define with enough parameters to
generate any version of the previous 8.

(This did not cause any change in generated asm)

Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 arch/riscv/include/asm/cmpxchg.h | 63 ++++++++++----------------------
 1 file changed, 19 insertions(+), 44 deletions(-)

diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index e49a2edc6f36c..715bf61e72c82 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -11,6 +11,17 @@
 #include <asm/barrier.h>
 #include <asm/fence.h>
 
+#define ___xchg(sfx, prepend, append)					\
+({									\
+	__asm__ __volatile__ (						\
+		prepend							\
+		"	amoswap" sfx " %0, %2, %1\n"			\
+		append							\
+		: "=r" (__ret), "+A" (*__ptr)				\
+		: "r" (__new)						\
+		: "memory");						\
+})
+
 #define __xchg_relaxed(ptr, new, size)					\
 ({									\
 	__typeof__(ptr) __ptr = (ptr);					\
@@ -18,18 +29,10 @@
 	__typeof__(*(ptr)) __ret;					\
 	switch (size) {							\
 	case 4:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.w %0, %2, %1\n"			\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".w", "", "");					\
 		break;							\
 	case 8:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.d %0, %2, %1\n"			\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".d", "", "");					\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
@@ -51,20 +54,10 @@
 	__typeof__(*(ptr)) __ret;					\
 	switch (size) {							\
 	case 4:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.w %0, %2, %1\n"			\
-			RISCV_ACQUIRE_BARRIER				\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".w", "", RISCV_ACQUIRE_BARRIER);		\
 		break;							\
 	case 8:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.d %0, %2, %1\n"			\
-			RISCV_ACQUIRE_BARRIER				\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".d", "", RISCV_ACQUIRE_BARRIER);		\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
@@ -86,20 +79,10 @@
 	__typeof__(*(ptr)) __ret;					\
 	switch (size) {							\
 	case 4:								\
-		__asm__ __volatile__ (					\
-			RISCV_RELEASE_BARRIER				\
-			"	amoswap.w %0, %2, %1\n"			\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".w", RISCV_RELEASE_BARRIER, "");		\
 		break;							\
 	case 8:								\
-		__asm__ __volatile__ (					\
-			RISCV_RELEASE_BARRIER				\
-			"	amoswap.d %0, %2, %1\n"			\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".d", RISCV_RELEASE_BARRIER, "");		\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
@@ -121,18 +104,10 @@
 	__typeof__(*(ptr)) __ret;					\
 	switch (size) {							\
 	case 4:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.w.aqrl %0, %2, %1\n"		\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".w.aqrl", "", "");				\
 		break;							\
 	case 8:								\
-		__asm__ __volatile__ (					\
-			"	amoswap.d.aqrl %0, %2, %1\n"		\
-			: "=r" (__ret), "+A" (*__ptr)			\
-			: "r" (__new)					\
-			: "memory");					\
+		___xchg(".d.aqrl", "", "");				\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
-- 
2.40.0