Sauce: https://github.com/mit-pdos/xv6-riscv
> xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix Version 6 (v6). xv6 loosely follows the structure and style of v6, but is implemented for a modern RISC-V multiprocessor using ANSI C.
Book from a previous year: https://pdos.csail.mit.edu/6.828/2024/xv6/book-riscv-rev4.pd... (PDF)