We present a scalable set-valued safety-preserving hybrid controller for constrained continuous-time linear time-invariant (LTI) systems subject to additive disturbance/uncertainty. The approach relies on a conservative approximation of the discriminating kernel using a piecewise ellipsoidal algorithm with polynomial complexity. This precomputed approximation is used online to synthesize a permissive state-feedback control law that guarantees the satisfaction of all constraints despite potentially conflicting performance objectives. We show the results on a flight envelope protection problem for a quadrotor with actuation saturation and unknown wind disturbances.