Dear Community,
I am developing firmware for STM32l476VGT using Gnu Make Builder and "Ac6 STM32 MCU GCC" Toolchain. I encounter a memory related run time error during the startup (before main) of my controller. The error occurs during the execution of the LoopFillZeroBss section:
LoopFillZerobss: ldr r3, = _ebss cmp r2, r3 bcc FillZerobss /* Call the clock system intitialization function.*/ bl SystemInit /* Call static constructors */ bl __libc_init_array /* Call the application's entry point.*/ bl main LoopForever: b LoopForever .size Reset_Handler, .-Reset_Handler /** * @brief This is the code that gets called when the processor receives an * unexpected interrupt. This simply enters an infinite loop, preserving * the system state for examination by a debugger. * * @param None * @retval : None */ .section .text.Default_Handler,"ax",%progbits Default_Handler: Infinite_Loop: b Infinite_Loop .size Default_Handler, .-Default_Handler
After the execution of bl __libc_init_array I end up in the Infinite_Loop of the Default_Handler. It is worth noting, that this error can be influenced by the amount memory which is statically allocated. In my source code file there is an array
static uint8_t array[SIZE] = {0};
If SIZE is smaller than threshold1, I can enter main() without any problems. If SIZE is between threshold1 and threshold2 (with threshold1 < threshold2) then the behaviour is as described above. If SIZE exceeds threshold2, a linker error (section '.bss' will not fit in region 'RAM') is generated (as expected).
I have the following questions:
1. What exactly happens, when 'bl __libc_init_array' is executed?
2. How could the fail of this command possibly related to the memory usage?
Any thoughts or helpful sources on this topic would be greatly appreciated as well.
Kind regards
Oliver
I've seen this happen several times on various projects. The most common solution I have found is to go into your linker file and increase your stack size (I start with doubling just to make sure). For example, on the STM32 within STM32CubeIDE, you would look in the .ld file and locate the _Min_Stack_Size = 0x400;
/* Entry Point */ENTRY(Reset_Handler)/* Highest address of the user mode stack */_estack = 0x20028000; /* end of RAM *//* Generate a link error if heap and stack don't fit into RAM */_Min_Heap_Size = 0x200; /* required amount of heap */_Min_Stack_Size = 0x800; /* required amount of stack */