Multicore processors are currently the focus of new and future critical-system architectures. However, they introduce new problems in regards to safety and security requirements. Real-time control flow monitoring techniques were proposed as solutions to detect the most common types of program errors and security attacks. We propose a new way to use the latest debug and trace architectures to achieve full and isolated real-time control flow monitoring. We present an online trace decoder FPGA component as a solution in the search for scalable and portable monitoring architectures. Our FPGA accelerator achieves real-time CPU monitoring with only 8% of used resources in a Zynq-7000 FPGA.