Failure of companion computer

i am working on drone project.The flight controller selected is Pixhawk. I have some question regarding companion computer :
Suppose pixhawk get its commands from companion computer on drone. After start of a mission, companion computer get fails,does pixhawk continues on the given mission or not ?
If not what does the pixhawk do in this case does it hover or lands immediately ?

It would depend on failsafe configuration. Do you also have a ground control station connected?

How to define failsafe configuration. Can you plz explain what can we done in both cases i.e in presence and absence of ground control station