s390/kernel: unify EX_TABLE* implementations

Replace three implementations with one using using __stringify_in_c
macro conveniently "borrowed" from powerpc and microblaze.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/include/asm/asm-const.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_ASM_CONST_H
+#define _ASM_S390_ASM_CONST_H
+
+#ifdef __ASSEMBLY__
+#  define stringify_in_c(...)	__VA_ARGS__
+#else
+/* This version of stringify will deal with commas... */
+#  define __stringify_in_c(...)	#__VA_ARGS__
+#  define stringify_in_c(...)	__stringify_in_c(__VA_ARGS__) " "
+#endif
+#endif /* _ASM_S390_ASM_CONST_H */

arch/s390/include/asm/linkage.h

@@ -2,38 +2,26 @@
 #ifndef __ASM_LINKAGE_H
 #define __ASM_LINKAGE_H
 
+#include <asm/asm-const.h>
 #include <linux/stringify.h>
 
 #define __ALIGN .align 4, 0x07
 #define __ALIGN_STR __stringify(__ALIGN)
 
-#ifndef __ASSEMBLY__
-
 /*
  * Helper macro for exception table entries
  */
-#define EX_TABLE(_fault, _target)	\
-	".section __ex_table,\"a\"\n"	\
-	".align	4\n"			\
-	".long	(" #_fault ") - .\n"	\
-	".long	(" #_target ") - .\n"	\
-	".previous\n"
 
-#else /* __ASSEMBLY__ */
+#define __EX_TABLE(_section, _fault, _target)				\
+	stringify_in_c(.section	_section,"a";)				\
+	stringify_in_c(.align	4;)					\
+	stringify_in_c(.long	(_fault) - .;)				\
+	stringify_in_c(.long	(_target) - .;)				\
+	stringify_in_c(.previous)
 
 #define EX_TABLE(_fault, _target)					\
-	.section __ex_table,"a"	;	\
-	.align	4 ;			\
-	.long	(_fault) - . ;		\
-	.long	(_target) - . ;		\
-	.previous
-
+	__EX_TABLE(__ex_table, _fault, _target)
 #define EX_TABLE_DMA(_fault, _target)					\
-	.section .dma.ex_table, "a" ;	\
-	.align	4 ;			\
-	.long	(_fault) - . ;		\
-	.long	(_target) - . ;		\
-	.previous
+	__EX_TABLE(.dma.ex_table, _fault, _target)
 
-#endif /* __ASSEMBLY__ */
 #endif