MARSS-RISCV Disk Images

This repository contains 32-bit and 64-bit RISC-V Linux disk images and bootloaders to be used with MARSS-RISCV.

Prerequisites

• To be able to clone the repository correctly, git-lfs must be installed on the system. See https://github.com/git-lfs/git-lfs/wiki/Installation for distro-specific installation instructions.

• Although the disk images are generic, the kernel + bootloader is meant to be used wit MARSS-RISCV and temu. See https://bellard.org/temu/ for more details.

• The disk images need to be decompressed using xz which is part of the xz utils package. See https://tukaani.org/xz/ for more details.

• To be able to grow the free space on the disk image, e2fsprogs is required. Most Linux distros have this installed by default. See http://e2fsprogs.sourceforge.net/ for more details.

How to use?

Each directory represents a specific configuration and contains a userland disk image, bootloader, kernel and riscvemu config file. The disk images are compressed with xz for storage efficiency. The file PACKAGES lists the packages present in the image.

Follow the instructions below after cloning the repository to get started:

• cd into the target directory

  $ cd riscv32-unknown-linux-gnu
  

• Decompress the image using xz

  $ xz -d -k -T 0 riscv32.img.xz
  

• Run MARSS-RISCV using the provided config file

  $ marss-riscv riscvemu.cfg
  

Note that the file system on the disk image has almost no space. To grow the file system follow the steps below:

• Grow the image file to the desired size (1GB in this example):

  $ truncate --size 1G riscv32.img
  

• Attach the disk image to a loopback device

  # losetup /dev/loop0 riscv32.img
  

• Run fsck before growing the file system

  # e2fsck -f /dev/loop0
  

• Grow the file system to its maximum size

  # resize2fs /dev/loop0
  

• Run fsck post resize

  # e2fsck -f /dev/loop0
  

• Detach the loopback device

  # losetup -d /dev/loop0
  

MARSS-RISCV does not propagate file changes to the disk image by default and discards them upon shutdown. For persistency, pass -rw to marss-riscv on the command line.

Available Configurations

riscv32-unknown-linux-gnu

A 32 bit Gentoo linux image cross-compiled using crossdev. Has a complete toolchain. Everything is compiled with the following flags:

CFLAGS="-O2 -pipe -fomit-frame-pointer -g -march=rv32g -mabi=ilp32d"
CXXLAGS="-O2 -pipe -fomit-frame-pointer -g"

Currently, gdb isn't functioning properly.