Recent developments in the field of reconfigurable SoC devices (FPGAs)will enable the development of embedded systems where software tasks, running on a CPU, can coexist with hardware tasks. We devised a real-time computing architecture that can integrate hardware and software executions in a transparent manner, and can support real-time QoS adaptation by means of partial reconfiguration of modern FPGA devices. Tasks are allowed to migrate seamlessly from CPU to FPGA and vice versa to support dynamic QoS adaptation and cope with dynamic workloads. In this paper, we discuss the design and implementation of an on-chip infrastructure, OS extensions and task design methodology that enable hardware-software transparency in the presence of relocation. The overall architecture is suitable to schedule real-time workloads and we derive bounds on relocation overhead. Finally, we show the applicability of our design methodology on a concrete task design case.