Simple Memory Protection for Embedded Operating System Kernels

This work describes the design and implementation of memory protection in the Roadrunner operating system. The design is portable between various CPUs that provide page-level protection using Memory-Management Unit (MMU) hardware. The approach overlays protection domains on regions of physical memory that are in use by application processes and the operating system kernel. An analysis of code size shows that this design and implementation can be executed with an order of magnitude less code than that of implementations providing separate address spaces.