Porting User Mode Linux to Ultrasparc Architecture

This paper describes the effort of porting User Mode Linux (UML) to Ultrasparc architecture. UML, which is a port of Linux to itself, acts as a great tool for kernel development and debugging, provides virtual networking, virtual hosting, acts as a secure sandbox or jail and provides a complete authentic Linux environment for other operating systems. But UML was developed for and currently runs only on Intel x86 architecture. The PPC port was started but ended up being stale. There is an ongoing effort of porting it to Windows OS on top of cygwin.[1]

Porting often shows weaknesses in the original code thus making parent code stronger. porting UML to Ultrasparc or Sparc64 architecture would definitely help it to get ported to other architectures and provide Sparc Linux kernel developers, a better development environment to work with. Given a better development environment, in turn will help make Sparc Linux port much stronger.

UML includes some details of the underlying architecture like register names, storage of system call numbers, arguments and return values in register set, organization of process address space, etc. A potential problem for UML not being supported on all architectures is the ability of ptrace to change system call numbers and thus the ability to virtualize system call numbers. Filling in most of the architecture-specific details currently makes it to compile and "almost" run on Ultrasparc.