OFFIS is developing an open source on-chip co-processor for RISC-V processors to enable high-speed, high-resolution monitoring of timing and behavioral properties on a larger scale than is currently possible. The co-processor allows monitoring of complex application-level processors with full cycle accuracy.
In the design flow of safety-critical applications, the specification of strict timing properties and behavioral guarantees is crucial. One well-known specification method is Contract-Based Design using assume-guarantee contracts. A system model containing such contracts provides a perfect basis for deriving run-time monitor specifications automatically. These specifications are then executed by our newly designed co-processor to achieve continuous monitoring of safety-relevant properties even in large-scale and dynamically evolving applications.
The mentioned contracts supervise various safety requirements covering functional and non-functional properties such as timing, temperature ranges or software parameters. This allows monitoring that a specific controller maintains a parameter within a defined range over a specified time frame, such as running closed-loop motor control parallel to the execution of a specific resource-heavy task, or that a complex AI algorithm always completes its execution within a specified period.
Our contract-based runtime monitoring approach consists of three interacting components:
At its core, the Time Contract Co-Processor (TCCP) connects to two other components, the TCCP-Compiler and the observer interfaces.
The TCCP executes contract-based specifications in hardware, it observes various event sources via an observer interface. The observers are minimalistic adapters to source data, like a RISC-V trace port to observe computational progress or a memory content observer. The TCCP monitors events according to its programmable configuration derived from contract specifications. These specifications are processed by the TCCP compiler, which generates a configuration program for the TCCP. The coprocessor is specifically designed to allow high monitoring capacity and cycle-accurate temporal resolution. Furthermore, enabling updateable contracts via the compiler provides a substantial increase in flexibility over existing statically configured hardware-monitoring approaches.
About OFFIS
OFFIS, an affiliated institute of the Carl von Ossietzky Universität Oldenburg, has been transforming scientific expertise in computer science into innovations since its founding in 1991. These innovations are further developed into marketable products by industrial partners.
The OFFIS production division focuses on the digital transformation of traditional production systems and processes, aiming to achieve various goals. These include improving the efficiency of individual processes or production steps in assembly lines, enabling better cooperation between different machines, enhancing availability through predictive maintenance, and improving quality through error detection during manufacturing.
