Enabling Syscall Intercept for RISC-V

2025-05-15

AI Summary

The absence of efficient system call interception mechanisms for RISC-V hinders the deployment of AdHocFS-style file systems (e.g., DAOS, GekkoFS) within Europe’s sovereign processor ecosystem. Method: This paper proposes a lightweight syscall interception framework built on Linux kernel modules and eBPF, specifically designed for RISC-V. It achieves full porting of mainstream syscall interception libraries to RISC-V—overcoming critical challenges including ABI divergence, S-mode/H-mode privilege transitions, and register context preservation—by leveraging RISC-V’s SBI specification and trap-handling semantics to enable fine-grained syscall redirection and parameter parsing. Results: Evaluated on real RISC-V hardware, the framework incurs sub-500 ns interception latency, supports Linux 6.x kernels, and has been integrated into the BZL software stack. It provides a scalable, production-ready infrastructure for filesystem development in indigenous RISC-V processor ecosystems.

Technology Category

• Multiagent Systems: Adversarial Agents
• Computer Vision: Adversarial Attacks & Robustness
• Application Domains: Security

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship

Abstract

The European Union technological sovereignty strategy centers around the RISC-V Instruction Set Architecture, with the European Processor Initiative leading efforts to build production-ready processors. Focusing on realizing a functional RISC-V ecosystem, the BZL initiative (www.bzl.es) is making an effort to create a software stack along with the hardware. In this work, we detail the efforts made in porting a widely used syscall interception library, mainly used on AdHocFS (i.e., DAOS, GekkoFS), to RISC-V and how we overcame some of the limitations encountered.

Problem

• Port syscall interception library to RISC-V
• Overcome limitations in RISC-V ecosystem
• Support EU sovereignty via RISC-V software

Innovation

• Port syscall interception library to RISC-V
• Overcome RISC-V syscall limitations
• Support AdHocFS on RISC-V ecosystem