ppc64: Only do an exception check if an 0x380 ends up in do_page_fault.

arch/ppc64/mm/fault.c

@@ -68,11 +68,19 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 
 #ifdef CONFIG_DEBUG_KERNEL
 	if (debugger_fault_handler && (regs->trap == 0x300 ||
-				regs->trap == 0x380)) {
+				       regs->trap == 0x380)) {
 		debugger_fault_handler(regs);
 		return;
 	}
+#endif
+
+	/* On an SLB miss we can only check for a valid exception entry */
+	if (regs->trap == 0x380) {
+		bad_page_fault(regs, address, SIGSEGV);
+		return;
+	}
 
+#ifdef CONFIG_DEBUG_KERNEL
 	if (error_code & 0x00400000) {
 		/* DABR match */
 		if (debugger_dabr_match(regs))