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From:   WANG Xuerui <kernel@xen0n.name>
To:     Huacai Chen <chenhuacai@kernel.org>
Cc:     WANG Rui <wangrui@loongson.cn>, Xi Ruoyao <xry111@xry111.site>,
        loongarch@lists.linux.dev, linux-kbuild@vger.kernel.org,
        llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
        WANG Xuerui <git@xen0n.name>
Subject: [PATCH 4/9] LoongArch: Make {read,write}_fcsr compatible with LLVM/Clang
Date:   Fri, 23 Jun 2023 21:43:46 +0800
Message-Id: <20230623134351.1898379-5-kernel@xen0n.name>
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From: WANG Xuerui <git@xen0n.name>

LLVM/Clang does not see FCSRs as GPRs, so make use of compiler
built-ins instead for better maintainability with less code.

The existing version cannot be wholly removed though, because the
built-ins, while available on GCC too, is predicated TARGET_HARD_FLOAT,
which means soft-float code cannot make use of them.

Signed-off-by: WANG Xuerui <git@xen0n.name>
---
 arch/loongarch/include/asm/loongarch.h | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index ac83e60c60d1..eedc313b5241 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -1445,12 +1445,6 @@ __BUILD_CSR_OP(tlbidx)
 #define EXCCODE_INT_START	64
 #define EXCCODE_INT_END		(EXCCODE_INT_START + EXCCODE_INT_NUM - 1)
 
-/* FPU register names */
-#define LOONGARCH_FCSR0	$r0
-#define LOONGARCH_FCSR1	$r1
-#define LOONGARCH_FCSR2	$r2
-#define LOONGARCH_FCSR3	$r3
-
 /* FPU Status Register Values */
 #define FPU_CSR_RSVD	0xe0e0fce0
 
@@ -1487,6 +1481,18 @@ __BUILD_CSR_OP(tlbidx)
 #define FPU_CSR_RU	0x200	/* towards +Infinity */
 #define FPU_CSR_RD	0x300	/* towards -Infinity */
 
+#ifdef CONFIG_CC_IS_CLANG
+#define LOONGARCH_FCSR0	0
+#define LOONGARCH_FCSR1	1
+#define LOONGARCH_FCSR2	2
+#define LOONGARCH_FCSR3	3
+#define read_fcsr(source)	__movfcsr2gr(source)
+#define write_fcsr(dest, val)	__movgr2fcsr(dest, val)
+#else /* CONFIG_CC_IS_CLANG */
+#define LOONGARCH_FCSR0	$r0
+#define LOONGARCH_FCSR1	$r1
+#define LOONGARCH_FCSR2	$r2
+#define LOONGARCH_FCSR3	$r3
 #define read_fcsr(source)	\
 ({	\
 	unsigned int __res;	\
@@ -1503,5 +1509,6 @@ do {	\
 	"	movgr2fcsr	"__stringify(dest)", %0	\n"	\
 	: : "r" (val));	\
 } while (0)
+#endif /* CONFIG_CC_IS_CLANG */
 
 #endif /* _ASM_LOONGARCH_H */
-- 
2.40.0