Next-generation safety-critical systems, such as autonomous vehicles, are increasingly complex systems integrating high-performance computing devices, diverse software stacks, machine learning algorithms and software applications of different safety criticality. Industry and academia are showing growing interest in using Linux as a general-purpose operating system in these safety-critical systems due to its widespread adoption in embedded systems and critical domains (e.g., telecommunications, banking) and widespread support of computing devices, software stacks and machine learning software. However, meeting the requirements of safety standards, such as systematic error reduction techniques, random fault tolerance, and temporal and spatial independence, becomes a challenge. This is especially the case when integrating software applications of different safety criticality (mixed criticality). This literature survey examines works that propose, analyze and extend Linux for the development of safety-critical systems. We also identify the main challenges these works focus on. Finally, we also present an overview of the main industry efforts.

Modern transportation and industrial domain safety-critical applications, such as autonomous vehicles and collaborative robots, exhibit a combination of escalating software complexity and the need to integrate diverse software stacks and machine learning algorithms, consequently demanding complex high-performance hardware. Linux’s extensive platform support and library ecosystem make it a valuable general-purpose operating system for developing complex software systems. However, because the Linux kernel has not been designed to comply with safety standards, it has a high execution path variability and does not provide execution time guarantees. In this context, several research initiatives have studied the usage of Linux for developing complex safety-related systems, focusing on topics that include its development process, isolation architectures, or test coverage estimation. Nonetheless, execution-time analysis and providing temporal guarantees is still a challenge. This work extends the novel statistical analysis of Linux system call execution paths with the analysis of execution-time variability and proposes a method for estimating the worst-case execution time, forming a sound approach for an in-depth analysis of the Linux kernel execution paths and execution times for safety-related systems. The proposed method is applied to a representative use case that implements an Autonomous Emergency Brake application in an NVIDIA Jetson Nano board connected to the CARLA autonomous driving simulator.

The goal of the H2020 SELENE project is the development of a flexible computing platform for autonomous applications that includes built-in hardware support for safety. The SELENE computing platform is an open-source RISC-V heterogeneous multicore system-on-chip (SoC) that includes 6 NOEL-V RISC-V cores and artificial intelligence accelerators. In this paper, we describe the approach followed in the SELENE project to accelerate neural network inference processes. Our intermediate results show that both the FPGA and ASIC accel-erators provide real-time inference performance for the analyzed network models at a reasonable implementation cost.

Existing HW/SW platforms for safety-critical systems suffer from limited performance and/or from lack of flexibility due to building on specific proprietary components. This jeopardizes their wide deployment across domains. While some research has been done to overcome these limitations, they have had limited success owing to missing flexibility and extensibility. Flexibility and extensibility are the cornerstones of industry adoption: industries dealing in capital goods need technologies on which they can rely on during decades (e.g. avionics, space, automotive). SELENE aims at covering this gap by proposing a new family of safety-critical computing platforms, which builds upon open source components such as the RISC-V instruction set architecture, GNU/Linux, and the Jailhouse hypervisor. SELENE will develop an advanced computing platform that is able to: (1) adapt the system to the specific requirements of different application domains, to changing environmental conditions, and to internal conditions of the system itself; (2) allow the integration of applications of different criticalities and performance demands in the same platform, guaranteeing functional and temporal isolation properties; (3) achieve flexible diverse redundancy by exploiting the inherent redundant capabilities of the multicore; and (4) efficiently execute compute-intensive applications by means of specific accelerators.