iob-linux

This repository is a centralized resource containing essential tools for building a Linux Operating System tailored for the IOb-SoC-OpenCryptoLinux platform.

The Operating System comprises four key files: the OpenSBI binary file (fw_jump.bin), the device tree blob file (iob_soc.dtb), the Linux kernel Image file, and the compressed root file system file. Pre-built versions of these files are included in this repository under the software/OS_build directory. Additionally, a pre-built version of the Linux kernel for QEMU emulation is available under the same directory.

To recompile these files, utilize the provided Makefile commands detailed in the Makefile sections. For information on the necessary system requirements and development environment setup to compile all the essential files for running the Linux Operating System on IOb-SoC-OpenCryptoLinux, refer to the development environment section in this README.md.

Makefile Targets

build-OS

This is the main target that orchestrates the entire OS build process. It includes the following sub-targets:

• build-dts: Builds the IOb-SoC Device Tree.
• build-opensbi: Compiles the OpenSBI bootloader with IOb-SoC platform support.
• build-rootfs: Creates a minimal root filesystem using Busybox.
• build-linux-kernel: Builds the Linux kernel for the specified version.
• build-buildroot: Builds the root filesystem using Buildroot.

build-qemu

Compiles the QEMU target for testing the generated OS.

run-qemu

Runs QEMU to test the generated OS. This target assumes the QEMU target has been built successfully.

clean-OS

Cleans the entire OS build directory.

clean-opensbi

Cleans the OpenSBI build artifacts.

clean-rootfs

Cleans the Busybox root filesystem build artifacts.

clean-linux-kernel

Cleans the Linux kernel build artifacts.

clean-buildroot

Cleans the Buildroot build artifacts.

Makefile Variables

• LINUX_OS_DIR: Specifies the directory where the Linux OS is being built. The default value is the current working directory ($(CURDIR)).
• OS_SOFTWARE_DIR: Specifies the directory containing software-related files for the OS, such as configuration files and scripts.
• OS_BUILD_DIR: Specifies the directory where the final OS build artifacts will be placed.
• OS_SUBMODULES_DIR: Specifies the directory where external submodules (such as Linux kernel and Buildroot) are located.
• MACROS_FILE: Specifies the file containing macros for building the Device Tree and OpenSBI.
• LINUX_VERSION: Specifies the version of the Linux kernel to be used (default is 5.15.98).
• BUILDROOT_VERSION: Specifies the version of Buildroot to be used (default is buildroot-2022.02.10).

Before using this Makefile, ensure you have the necessary tools and dependencies installed. Customize these variables to match your project's directory structure and configurations.

Makefile Usage

1. Set the appropriate values for LINUX_OS_DIR, OS_SOFTWARE_DIR, OS_BUILD_DIR, and OS_SUBMODULES_DIR variables.
2. Run make build-OS to build the entire OS.
3. Optionally, run make build-qemu to build QEMU target.
4. Run make run-qemu to test the generated OS in QEMU.

Development Environment

Setting up the development environment is essential for building and testing your project. Whether you choose to work directly on your host machine, Nix environment, or within a Docker container, the following sections guide you through the necessary steps. Ensure that you have the required tools and dependencies installed to streamline the development process seamlessly.

Note: Instead of Docker, you may use the OpenSource solution Podman. Podman provides a lightweight, daemonless container engine that can be used as an alternative to Docker. The commands and workflows are similar, making it a viable choice for containerization in environments where Docker may not be the preferred option.

Without Docker nor Nix

• RISC-V Linux/GNU toolchain: Obtain from riscv-gnu-toolchain. After cloning the repository, navigate to the respective directory and configure with ./configure --prefix=/opt/riscv --enable-multilib. Build the Linux cross-compiler with make Linux.
• Linux Kernel development requirements: The required packages depend on the host OS. For Ubuntu or similar Debian-based distributions, refer to Kernel/BuildYourOwnKernel.
• dtc (device-tree-compiler): Install on Debian/Ubuntu with sudo apt-get install device-tree-compiler.
• Buildroot system requirements: Software dependencies are listed in the Buildroot manual.

With Nix

To start the Nix environment with included dependencies for building the Device Tree and OpenSBI, run:

• nix-shell

Note: nix-shell must be installed by the user.

Note: Currently, the Nix environment does not work for buildroot. Please disable the Nix environment before building with buildroot. Builroot also downloads most of it's dependencies automatically, so a Nix environment should not be required.

With Docker (Docker must be installed by the user)

To build the Docker image corresponding to this project's development environment:

• docker build --pull --rm -t iob_linux ".", or alternatively, you can pull the pre-built image: docker pull IObundle/iob-linux:latest

After a successful build, run a container in interactive mode:

• docker run -it iob_linux

If the user exits the container, they can restart it:

• docker restart <container_id>, where the <container_id> can be obtained from docker ps -a
• docker exec -it <container_id> bash to run an interactive shell

To copy files or folders to/from the container:

• docker cp CONTAINER:SRC_PATH DEST_PATH or docker cp SRC_PATH CONTAINER:DEST_PATH

For example, copying the output of make build-OS:

• docker cp a6a26dbec0cf:/iob_linux/software/OS_build/ software

Note: Docker must be installed by the user. If not already installed, please follow the instructions at https://docs.docker.com/engine/install/.

Acknowledgement

The OpenCryptoLinux project is funded through the NGI Assure Fund, a fund established by NLnet with financial support from the European Commission's Next Generation Internet programme, under the aegis of DG Communications Network, Content and Technology under grant agreement No 957073.