  ARM TrustZone is the de-facto hardware TEE implementation on mobile devices
like smartphones. As a vendor-centric TEE, TrustZone greatly overlooks the
strong protection demands and requirements from the App developers. Several
security solutions have been proposed to enable the TEE-assisted isolation in
the Normal World of ARM, attempting to balance the security and usability.
However, they are still not full-fledged in serving Apps' needs. In this paper,
we introduce LEAP, which is a lightweight App developer Centric TEE solution in
the Normal World. LEAP offers the auto DevOps tool to help developers to
prepare the codes running on it, enables isolated codes to execute in parallel
and access peripheral (e.g. mobile GPUs) with ease, and dynamically manage
system resources upon Apps' requests. We implement the LEAP prototype on the
off-the-shelf ARM platform without any hardware change. We perform the
comprehensive analyses and experiments to demonstrate that LEAP is efficient in
design, comprehensive in support, and convenient in adoption.
