Generating correct initial page tables from formal hardware descriptions

Abstract

Modern hardware platforms are increasingly complex and heterogeneous. System software uses a hodgepodge of different mechanisms and representations to express the memory topology of the target platform. Considerable maintenance effort is required to keep them in sync while often sharing is impossible due to hard-coded values. Incorrect platformspecific values in the hardware initialization sequence can lead to security critical and hard-to-find bugs because of misconfigured translation hardware, inaccessible devices, or the use of bad pointers.We present a better way for system software to express and initialize memory hardware. We adopt an existing, powerful hardware description language, and efficiently compile it to generate correct initial page tables and memory maps for OS kernels and firmware from a single system description. We evaluate our system on multiple architectures and platforms, and demonstrate that we can use the generated data structures to successfully initialize translation hardware, devices, memory maps, and allocators enabling easy support of new hardware platforms.