up on

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up on someone or something

Fig. knowledgeable about someone or something. Ask Tom about the author of this book. He's up on stuff like that.
See also: on, up
References in classic literature ?
Dad's put this duckin' act up on him two trips runnin'.
The dory surged up on the crest of a wave, and just when it seemed impossible that she could avoid smashing against the schooner's side, slid over the ridge, and was swallowed up in the damp dusk.
It's the second time they've sent me up on a trumped-up charge--I've had hard luck and can't pay them what they want.
The youngest child, a girl of six, was asleep, sitting curled up on the floor with her head on the sofa.
Commons' figures yesterday revealed average household energy bills were PS260 a year up on 2010.
A breakdown at some ungodly hour that finds you holed up on the side of the road or highway strips away that freedom leaving you frantically dialing numbers, trying in vain to get through to a tow company.