[POWERPC] Separate out legacy machine check exception parsers

Move out the old-style exception parsers to a separate function, and
don't call it on platforms that have a platform-specific handler.

It would make sense to move out the generic versions into their platforms
instead, but that can be done gradually down the road.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/traps.c

@@ -324,38 +324,10 @@ static inline int check_io_access(struct pt_regs *regs)
 #define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
 #endif
 
-void machine_check_exception(struct pt_regs *regs)
+static int generic_machine_check_exception(struct pt_regs *regs)
 {
-	int recover = 0;
 	unsigned long reason = get_mc_reason(regs);
 
-	/* See if any machine dependent calls */
-	if (ppc_md.machine_check_exception)
-		recover = ppc_md.machine_check_exception(regs);
-
-	if (recover)
-		return;
-
-	if (user_mode(regs)) {
-		regs->msr |= MSR_RI;
-		_exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
-		return;
-	}
-
-#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
-	/* the qspan pci read routines can cause machine checks -- Cort */
-	bad_page_fault(regs, regs->dar, SIGBUS);
-	return;
-#endif
-
-	if (debugger_fault_handler(regs)) {
-		regs->msr |= MSR_RI;
-		return;
-	}
-
-	if (check_io_access(regs))
-		return;
-
 #if defined(CONFIG_4xx) && !defined(CONFIG_440A)
 	if (reason & ESR_IMCP) {
 		printk("Instruction");
@@ -471,6 +443,42 @@ void machine_check_exception(struct pt_regs *regs)
 	}
 #endif /* CONFIG_4xx */
 
+	return 0;
+}
+
+void machine_check_exception(struct pt_regs *regs)
+{
+	int recover = 0;
+
+	/* See if any machine dependent calls */
+	if (ppc_md.machine_check_exception)
+		recover = ppc_md.machine_check_exception(regs);
+	else
+		recover = generic_machine_check_exception(regs);
+
+	if (recover)
+		return;
+
+	if (user_mode(regs)) {
+		regs->msr |= MSR_RI;
+		_exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
+		return;
+	}
+
+#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
+	/* the qspan pci read routines can cause machine checks -- Cort */
+	bad_page_fault(regs, regs->dar, SIGBUS);
+	return;
+#endif
+
+	if (debugger_fault_handler(regs)) {
+		regs->msr |= MSR_RI;
+		return;
+	}
+
+	if (check_io_access(regs))
+		return;
+
 	if (debugger_fault_handler(regs))
 		return;
 	die("Machine check", regs, SIGBUS);