Frozen Code Compression Technique as an On-demand Code Loading to Reduce the Footprint of Linux Kernel for Embedded Systems

The frozen code compression technique divides the unexecuted kernel code into single-entry partitions that are stored in compressed form, and replaced by stubs in the code. When control flow enters a stub, a special routine is invoked that allocates space and expands the corresponding code fragment, after which the stub is overwritten with a direct jump to the decompressed code. Once decompressed, code is never evicted from memory. The proposed technique will be useful in particular for streamlining a general-purpose OS kernel for use on an embedded system, removing as much of the aforementioned overhead as possible. We use Linux as a case study, but the approach is applicable to other operating systems as well.