RTMux is a lightweight open source para-virtualization layer, using resource-multiplexing techniques to provide a highly deterministic real-time environment for Linux/ARM. Typically, less than 500 lines modication against Linux kernel are required to allow additional RTOS executives on the same ARM core concurrently with real-time performance guarantees.
- Build RTMux-friendly RTOS
- RT-Thread Lite is the only RTOS supporting RTMux.
- SCons is required to build RT-Thread Lite.
- Fetch the source
git clone https://github.com/rtmux/rt-thread-lite.git rt-thread && cd rt-thread
- Configure and Build for the machines. Take Realview for ARM Cortex-A8 for example:
cd bsp/realview-a8 && scons
- Copy the generated file
rtthread.binto the path/tmp/rtos.bin
- Modifying Linux kernel is vital, and get the kernel source in advance. The version that RTMux supports is v3.8.13
- Apply the patches under directory patches/ against Linux source
patch -p1 < patches/0001-RTMux-implement-dual-kernel-approach-in-minimal-chan.patchpatch -p1 < patches/0002-RTMux-support-Realview-Platform-Baseboard-for-Cortex.patchpatch -p1 < patches/0003-RTMux-support-AM33x-based-platforms.patchpatch -p1 < patches/0004-arm-gic-correct-the-cpu-map-on-gic_raise_softirq-for.patch
- Enable
ARM_VMMin kernel configurations.make menuconfig ARCH=arm- At present, both Realview for ARM Cortex-A8 and Beaglebone Black (based on TI AM33x) are supported.
- Build the kernel image
make ARCH=arm CROSS_COMPILE=arm-none-eabi- zImage
- Build the virtual machime monitor module for Linux
make -C <kernel-source-path> M=$PWD ARCH=arm CROSS_COMPILE=arm-none-eabi-
- Repack the root filesystem and ensure the following changes:
- Copy the generated rtvmm.ko
- Put the RTMux-friendly RTOS image (that is,
/tmp/rtos.bin) under the path/vmm/rtos.bin.
- Insert vmm kernel module when you are about to launch the RTOS
insmod rtvmm.ko
- Linux domain would continue executing, and the real-time domain starts as expected.