Extending Lifetime of Embedded Systems by WebAssembly-based Functional Extensions Including Drivers

Abstract: Containerization has become a ubiquitous tool in software development. Due to its numerous benefits, including platform interoperability and secure execution of untrusted third-party code, this technology is a boon to industrial automation, promising to provide aid for their inherent challenges - except one, which is interaction with physical devices. Unfortunately, this presents a substantial barrier to widespread adoption. In response to this challenge, we present Wasm-IO, a framework designed to facilitate peripheral I/O operations within WebAssembly (Wasm) containers. We elucidate fundamental methodologies and various implementations that enable the development of arbitrary device drivers in Wasm. Thereby, we address the needs of the industrial automation sector, where a prolonged device lifetime combined with changing regulatory requirements and market pressure fundamentally contrasts vendors' responsibility concerns regarding post-deployment system modifications to incorporate new, isolated drivers. In this paper, we detail synchronous I/O and methods for embedding platform-independent peripheral configurations withinWasm binaries.We introduce an extended priority model that enables interrupt handling in Wasm while maintaining temporal isolation. Our evaluation shows that our proposed Wasm isolation can significantly reduce latency and overhead. The results of our driver case study corroborate this. We conclude by discussing overarching system designs that leverage Wasm-IO, including scheduling methodologies.