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Date: Sat, 18 Mar 2023 05:00:58 -0300
From: Leonardo Bras <leobras@...hat.com>
To: Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Leonardo Bras <leobras@...hat.com>, Guo Ren <guoren@...nel.org>
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 4/6] riscv/cmpxchg: Deduplicate xchg() asm functions
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@...hat.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..13dc608229ef0 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
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