s390/extable: add and use fixup_exception helper function

Add and use fixup_exception helper function in order to remove the
duplicated exception handler fixup code at several places.
Reviewed-by: NAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: NHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: NVasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/extable.h

@@ -49,17 +49,6 @@ ex_fixup_handler(const struct exception_table_entry *x)
 	return (ex_handler_t)((unsigned long)&x->handler + x->handler);
 }
 
-static inline bool ex_handle(const struct exception_table_entry *x,
-			     struct pt_regs *regs)
-{
-	ex_handler_t handler = ex_fixup_handler(x);
-
-	if (unlikely(handler))
-		return handler(x, regs);
-	regs->psw.addr = extable_fixup(x);
-	return true;
-}
-
 #define ARCH_HAS_RELATIVE_EXTABLE
 
 static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
@@ -78,4 +67,6 @@ static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
 }
 #define swap_ex_entry_fixup swap_ex_entry_fixup
 
+bool fixup_exception(struct pt_regs *regs);
+
 #endif

arch/s390/kernel/early.c

@@ -151,12 +151,8 @@ static __init void setup_topology(void)
 
 static void early_pgm_check_handler(struct pt_regs *regs)
 {
-	const struct exception_table_entry *fixup;
-
-	fixup = s390_search_extables(regs->psw.addr);
-	if (!fixup)
+	if (!fixup_exception(regs))
 		disabled_wait();
-	regs->psw.addr = extable_fixup(fixup);
 }
 
 static noinline __init void setup_lowcore_early(void)

arch/s390/kernel/kprobes.c

@@ -465,7 +465,6 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	struct kprobe *p = kprobe_running();
-	const struct exception_table_entry *entry;
 
 	switch(kcb->kprobe_status) {
 	case KPROBE_HIT_SS:
@@ -487,10 +486,8 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.
 		 */
-		entry = s390_search_extables(regs->psw.addr);
-		if (entry && ex_handle(entry, regs))
+		if (fixup_exception(regs))
 			return 1;
-
 		/*
 		 * fixup_exception() could not handle it,
 		 * Let do_page_fault() fix it.

arch/s390/kernel/traps.c

@@ -54,9 +54,7 @@ void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
 		force_sig_fault(si_signo, si_code, get_trap_ip(regs));
 		report_user_fault(regs, si_signo, 0);
         } else {
-                const struct exception_table_entry *fixup;
-		fixup = s390_search_extables(regs->psw.addr);
-		if (!fixup || !ex_handle(fixup, regs))
+		if (!fixup_exception(regs))
 			die(regs, str);
         }
 }
@@ -245,16 +243,12 @@ static void space_switch_exception(struct pt_regs *regs)
 
 static void monitor_event_exception(struct pt_regs *regs)
 {
-	const struct exception_table_entry *fixup;
-
 	if (user_mode(regs))
 		return;
 
 	switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) {
 	case BUG_TRAP_TYPE_NONE:
-		fixup = s390_search_extables(regs->psw.addr);
-		if (fixup)
-			ex_handle(fixup, regs);
+		fixup_exception(regs);
 		break;
 	case BUG_TRAP_TYPE_WARN:
 		break;

arch/s390/mm/extable.c

@@ -14,3 +14,18 @@ const struct exception_table_entry *s390_search_extables(unsigned long addr)
 	num = __stop_amode31_ex_table - __start_amode31_ex_table;
 	return search_extable(__start_amode31_ex_table, num, addr);
 }
+
+bool fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *ex;
+	ex_handler_t handler;
+
+	ex = s390_search_extables(instruction_pointer(regs));
+	if (!ex)
+		return false;
+	handler = ex_fixup_handler(ex);
+	if (unlikely(handler))
+		return handler(ex, regs);
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}

arch/s390/mm/fault.c

@@ -230,13 +230,8 @@ static noinline void do_sigsegv(struct pt_regs *regs, int si_code)
 
 static noinline void do_no_context(struct pt_regs *regs)
 {
-	const struct exception_table_entry *fixup;
-
-	/* Are we prepared to handle this kernel fault?  */
-	fixup = s390_search_extables(regs->psw.addr);
-	if (fixup && ex_handle(fixup, regs))
+	if (fixup_exception(regs))
 		return;
-
 	/*
 	 * Oops. The kernel tried to access some bad page. We'll have to
 	 * terminate things with extreme prejudice.