riscv: extable: consolidate definitions

This is a riscv port of commit 819771cc ("arm64: extable:
consolidate definitions").
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/include/asm/asm-extable.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_ASM_EXTABLE_H
+#define __ASM_ASM_EXTABLE_H
+
+#ifdef __ASSEMBLY__
+
+#define __ASM_EXTABLE_RAW(insn, fixup)		\
+	.pushsection	__ex_table, "a";	\
+	.balign		4;			\
+	.long		((insn) - .);		\
+	.long		((fixup) - .);		\
+	.popsection;
+
+	.macro		_asm_extable, insn, fixup
+	__ASM_EXTABLE_RAW(\insn, \fixup)
+	.endm
+
+#else /* __ASSEMBLY__ */
+
+#include <linux/stringify.h>
+
+#define __ASM_EXTABLE_RAW(insn, fixup)			\
+	".pushsection	__ex_table, \"a\"\n"		\
+	".balign	4\n"				\
+	".long		((" insn ") - .)\n"		\
+	".long		((" fixup ") - .)\n"		\
+	".popsection\n"
+
+#define _ASM_EXTABLE(insn, fixup) __ASM_EXTABLE_RAW(#insn, #fixup)
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_ASM_EXTABLE_H */

arch/riscv/include/asm/futex.h

@@ -11,6 +11,7 @@
 #include <linux/uaccess.h>
 #include <linux/errno.h>
 #include <asm/asm.h>
+#include <asm/asm-extable.h>
 
 /* We don't even really need the extable code, but for now keep it simple */
 #ifndef CONFIG_MMU

arch/riscv/include/asm/uaccess.h

@@ -8,14 +8,9 @@
 #ifndef _ASM_RISCV_UACCESS_H
 #define _ASM_RISCV_UACCESS_H
 
+#include <asm/asm-extable.h>
 #include <asm/pgtable.h>		/* for TASK_SIZE */
 
-#define _ASM_EXTABLE(from, to)						\
-	"	.pushsection	__ex_table, \"a\"\n"			\
-	"	.balign		4\n"					\
-	"	.long		(" #from " - .), (" #to " - .)\n"	\
-	"	.popsection\n"
-
 /*
  * User space memory access functions
  */

arch/riscv/lib/uaccess.S

 #include <linux/linkage.h>
 #include <asm-generic/export.h>
 #include <asm/asm.h>
+#include <asm/asm-extable.h>
 #include <asm/csr.h>
 
 	.macro fixup op reg addr lbl
 100:
 	\op \reg, \addr
-	.section __ex_table,"a"
-	.balign 4
-	.long (100b - .), (\lbl - .)
-	.previous
+	_asm_extable	100b, \lbl
 	.endm
 
 ENTRY(__asm_copy_to_user)