Porting HelenOS to RISC-V
RISC-V is the most recent attempt (originally from UC Berkeley) to design a brand new instruction set architecture based on the reduced instruction set computing (RISC) principles. One of its goals is to be completely open and free (both as in free beer and as in free speech) for designers, users and manufacturers. HelenOS is an open source operating system designed and implemented from scratch based on the microkernel multiserver design principles. One of its goals is to provide excellent target platform portability and it currently supports 8 different hardware platforms.
Both projects are still in the process of maturing: While the unprivileged (user space) instruction set architecture of RISC-V has been declared stable in 2014, the privileged instruction set architecture is still in a stage of draft and is allowed to change in the future. Likewise, many major design features and building blocks of HelenOS are already in place, but no official commitment to ABI or API stability has been made yet.
This talk introduces both projects, presents the initial lessons learned from porting HelenOS to RISC-V and evaluates the portability of HelenOS on yet another porting effort.