Porting and Generalizing Dynamic Privilege in Linux - Devconf.US pretalx

Dynamic Privilege is the ability for an authorized process to acquire and relinquish hardware privilege (supervisor privilege) on the fly. Recent work in our research group introduced the notion of Dynamic Privilege, and the attendant kernel mechanisms to introduce it to the Linux kernel. This permits the exploration of several interesting optimizations and novel approaches to system specialization - for example, shortcutting long code paths by calling internal kernel routines. The initial implementation was developed in x86_64. In this talk, we will present our work in porting the core primitives for Dynamic Privilege to ARM64 and discuss the details of this approach. Through a comparison of the ARM64 and x86 implementations, we will seek to differentiate the functional goal of Dynamic Privilege from the underlying architectural mechanisms. In doing so, we will summarize what we have learned through the process of generalizing its implementation beyond a single architecture. Finally, we will discuss how our experiences introducing the mechanism to ARM64 inform a natural path towards a RISC-V implementation which we will briefly introduce.