s390/bug: Introduce and use monitor code macro

The first operand address of the monitor call (mc) instruction is the
monitor code. Currently the monitor code is ignored, but this will
change. Therefore add and use MONCODE_BUG instead of a hardcoded zero.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/include/asm/bug.h

@@ -3,7 +3,11 @@
 #define _ASM_S390_BUG_H
 
 #include <linux/compiler.h>
+#include <linux/const.h>
 
+#define	MONCODE_BUG	_AC(0, U)
+
+#ifndef __ASSEMBLER__
 #if defined(CONFIG_BUG) && defined(CONFIG_CC_HAS_ASM_IMMEDIATE_STRINGS)
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
@@ -24,7 +28,7 @@
 #define __BUG_ASM(cond_str, flags)					\
 do {									\
 	asm_inline volatile("\n"					\
-		"0:	mc	0,0\n"					\
+		"0:	mc	%[monc](%%r0),0\n"			\
 		"	.section __bug_table,\"aw\"\n"			\
 		"1:	.long	0b - .	# bug_entry::bug_addr\n"	\
 		__BUG_ENTRY_VERBOSE("%[frmt]", "%[file]", "%[line]")	\
@@ -32,7 +36,8 @@ do {									\
 		"	.org	1b+%[size]\n"				\
 		"	.previous"					\
 		:							\
-		: [frmt] "i" (WARN_CONDITION_STR(cond_str)),		\
+		: [monc] "i" (MONCODE_BUG),				\
+		  [frmt] "i" (WARN_CONDITION_STR(cond_str)),		\
 		  [file] "i" (__FILE__),				\
 		  [line] "i" (__LINE__),				\
 		  [flgs] "i" (flags),					\
@@ -54,6 +59,7 @@ do {									\
 #define HAVE_ARCH_BUG_FORMAT
 
 #endif /* CONFIG_BUG && CONFIG_CC_HAS_ASM_IMMEDIATE_STRINGS */
+#endif /* __ASSEMBLER__ */
 
 #include <asm-generic/bug.h>
 

arch/s390/kernel/traps.c

@@ -258,11 +258,12 @@ static void __init test_monitor_call(void)
 	if (!IS_ENABLED(CONFIG_BUG))
 		return;
 	asm_inline volatile(
-		"	mc	0,0\n"
+		"	mc	%[monc](%%r0),0\n"
 		"0:	lhi	%[val],0\n"
 		"1:\n"
 		EX_TABLE(0b, 1b)
-		: [val] "+d" (val));
+		: [val] "+d" (val)
+		: [monc] "i" (MONCODE_BUG));
 	if (!val)
 		panic("Monitor call doesn't work!\n");
 }