Last modified: Sat Apr 9 03:11:32 2016 GMT.
This paper reports our experience applying XCAP---a recent theoretical verification framework---to certify a realistic x86 implementation of machine context management. XCAP supports expressive and modular logical specifications, but has only previously been applied on simple idealized machine and code. By applying the XCAP theory to an x86 machine model, building libraries of common proof tactics and lemmas, composing specifications for the context data structures and routines, and proving that the code behave accordingly, we achieved the first formal, modular, and mechanized verification of realistic x86 context management code. Our proofs are fully mechanized in the Coq proof assistant. Our certified library code runs on stock hardware and can be linked with other certified systems and application code. Our technique applies to other variants or extensions of context management (e.g., more complex context, different platforms), provides a solid basis for further verification of thread implementation and concurrent programs, and illustrates how to achieve formal, modular, and mechanized verification of realistic systems code.