Introduction

This repo can be used to build a 2.6.31.x Linux kernel for the MIPS Malta board usable with QEMU. It's forked from the firmadyne repo but it does not include the firmadyne module, though many of the other customizations are still included (ssh, other services). No filesystem image is provided.

Changing Kernel Versions

The kernel version to be build can be updated by modifying the Makefile at the root of the repo at changing these lines at the top of the file:

# version - 2.6.31.6
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 31
EXTRAVERSION = .6

Usage

Docker Build

The build can be run using the included Docker container:

sudo docker build -t ubuntu-1604-builder -f ubuntu_16.04-gcc-mips-linux-gnu.Dockerfile
sudo docker run -it --rm -v $PWD:/home/builder/images ubuntu-1604-builder

cd images/
mkdir -p build/mipseb
cp config.mipseb build/mipseb/.config
make ARCH=mips CROSS_COMPILE=mips-linux-gnu- O=./build/mipseb -j8

Since MIPS systems can be either big-endian or little-endian, the kernel can be compiled for both endianness.

Little-Endian (MIPSEL) Build

Create the kernel build output directory:

mkdir -p build/mipsel

Copy the configuration file into the build directory:

cp config.mipsel build/mipsel/.config

Assuming that the appropriate cross-compiler is installed in /opt/cross/mipsel-linux-musl, execute:

make ARCH=mips CROSS_COMPILE=/opt/cross/mipsel-linux-musl/bin/mipsel-linux-musl- O=./build/mipsel -j8

Alternative command for Ubuntu/Debian systems with the gcc-mipsel-linux-gnu metapackage installed:

make ARCH=mips CROSS_COMPILE=mipsel-linux-gnu- O=./build/mipsel -j8

The output kernel image will be generated at the following location:

build/mipsel/vmlinux

Big-Endian (MIPSEB) Build

Create the kernel build output directory:

mkdir -p build/mipseb

Copy the configuration file into the build directory:

cp config.mipseb build/mipseb/.config

Assuming that the appropriate cross-compiler is installed in /opt/cross/mipseb-linux-musl, execute:

make ARCH=mips CROSS_COMPILE=/opt/cross/mipseb-linux-musl/bin/mipseb-linux-musl- O=./build/mipseb -j8

Alternative command for Ubuntu/Debian systems with the gcc-mips-linux-gnu metapackage installed:

make ARCH=mips CROSS_COMPILE=mips-linux-gnu- O=./build/mipseb -j8

The output kernel image will be generated at the following location:

build/mipseb/vmlinux

Notes

This instrumented MIPS kernel is built for the ARCH_MALTA MIPS Malta target with a 24kf processor. As a result, hardware support on this emulated target is limited to peripherals that are both available on the emulated target and supported by QEMU. Since an emulated PCI bus is available and supported, this allows additional ethernet devices (e.g. rtl8139, smc91c111, pcnet32, etc.) to be attached to the virtualized system. Emulated hard drives can be attached using the IDE block device interface.

As future work, it may be useful to switch to VirtIO on MIPS, since support has been recently merged into the Linux kernel. However, this would require a kernel upgrade. Additionally, it may be useful to add support for MIPS64 systems, although these do not appear to be prevalent. Nevertheless, at the time, we performed our published experiments over our dataset using this kernel for MIPS systems.