There is important information there: https://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html - and you will find some worked examples here https://github.com/FreeRTOS/FreeRTOS/blob/V10.2.1-convergence/FreeRTOS/Demo/CORTEX_A9_Zynq_ZC702/RTOSDemo/src/Full_Demo/IntQueueTimer.c