kdump: Modify kdump script to start the firmware assisted dump.

During service kdump start, if firmware assisted dump is not enabled then
fallback to starting of existing kexec based kdump.  If firmware assisted
is enabled but not running, then start firmware assisted dump by echo'ing
1 to '/sys/kernel/fadump_registered' file.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

kdumpctl

@@ -662,6 +662,29 @@ check_dump_feasibility()
 	return $?
 }
 
+start_fadump()
+{
+	echo 1 > $FADUMP_REGISTER_SYS_NODE
+	if ! check_current_fadump_status; then
+		echo "fadump: failed to register"
+		return 1
+	fi
+
+	echo "fadump: registered successfully"
+	return 0
+}
+
+start_dump()
+{
+	if [ $DEFAULT_DUMP_MODE == "fadump" ]; then
+		start_fadump
+	else
+		load_kdump
+	fi
+
+	return $?
+}
+
 start()
 {
 	check_config
@@ -703,7 +726,8 @@ start()
 		echo "Starting kdump: [FAILED]"
 		return 1
 	fi
-	load_kdump
+
+	start_dump
 	if [ $? != 0 ]; then
 		echo "Starting kdump: [FAILED]"
 		return 1