Abstract: FreeRTOS, as an open source lightweight multi-task real-time operating system, is widely used in all kinds of embedded instruments and equipments. But FreeRTOS does not support the dynamic loading of the software module, which limits its flexibility and scalability. Based on the detailed analysis of symbol relocation principle in the ELF file, dynamic loading and unloading function of the software module is realized by modifying the memory layout for FreeRTOS task, and adding the ELF file loader in the kernel. The test results on the STM32 platform show that the software module can be dynamically loaded into the memory and successfully scheduled by the kernel, while the OS is running.
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Key words: FreeRTOS, ELF file, dynamic software module, symbol relocation