Our current project includes FreeRTOS, and I added –useframepointer to Keil uVision’s ARMGCC compiler option. But after loading firmware into STM32F104 chip, then runs it, it crashed. Without –useframepointer, everything is OK. The hard fault handler shows that faultStackAddress is 0x40FFFFDC, which points to a reserved area. Does anyone has any idea of this error? Thanks a lot. ~~~~ __asm void HardFaultHandler(void) { TST lr, #4 ITE EQ MRSEQ r0, MSP MRSNE r0, PSP B __cpp(HardFaultHandler) } void HardFaultHandler(uint32t *faultStackAddress) { } ~~~~ I stepped into each line of code, and the crash happened in below function in FreeRTOS’s port.c after I called vTaskDelete(NULL); ~~~~ void vPortYieldFromISR( void ) { /* Set a PendSV to request a context switch. */ portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT; } ~~~~ But seems like this is not the root cause, because when I deleted vTaskDelete(NULL), crash still happened.

I’m afraid without reading the compiler documentation, or inspecting the changes to the generated assembler code, I don’t know why this would be. The code assumes the compiler generates ARM EABI compliant code, maybe using the frame pointer changes that? Why do you need that compiler option?

We’d like to unwind ARM Cortex M3 stack when crash happened, so we need to save FP(Frame Pointer) to the stack. That’s why we add –useframepointer to Keil uVision’s ARMGCC compiler option.

I found that if I comment out the xTimerCreateTimerTask() in vTaskStartScheduler() function, the crash does not happen. Any thoughts? Thanks.

My test code for your reference: ~~~~

include “FreeRTOSConfig.h”

include “FreeRTOS.h”

include “task.h”

include <stm32f10x.h>

void crashTask(void *param) {

unsigned int i = 0;
/* halt the hardware. */
while(1)
{
     i += 1;
}
vTaskDelete(NULL);

} void testCrashTask() { xTaskCreate(crashTask, (const signed char *)”crashTask”, configMINIMAL_STACK_SIZE, NULL, 1, NULL);
} void HardFaultHandler(unsigned int *faultStackAddress); /* The fault handler implementation calls a function called HardFaultHandler(). */

if defined(__CC_ARM)

__asm void HardFaultHandler(void) { TST lr, #4 ITE EQ MRSEQ r0, MSP MRSNE r0, PSP B __cpp(HardFault_Handler) }

else

void HardFault_Handler(void) { __asm(“TST lr, #4”); __asm(“ITE EQ”); __asm(“MRSEQ r0, MSP”); __asm(“MRSNE r0, PSP”); __asm(“B Hard_Fault_Handler”); }

endif

void HardFaultHandler(unsigned int *faultStackAddress) { int i = 0; while(1) { i += 1; } } void nvicInit(void) {

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
#ifdef  VECT_TAB_RAM                            
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);     
#else
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);  
#endif

} int main() { nvicInit();

testCrashTask();
vTaskStartScheduler();

} /* For now, the stack depth of IDLE has 88 left. if want add func to here, you should increase it. / void vApplicationIdleHook(void) { / ATTENTION: all funcs called within here, must not be blocked */ //workerProbe(); } void debugSendTraceInfo(unsigned int taskNbr) { } ~~~~

The timer task is a standard task, written in C, so there is nothing special about it that I am aware of. It does however give a big clue as to where you could focus your debugging. See how far you get through the function – it is actually quite small.

Seems like SP is corrupted. Another odd thing is that if I debug it and step into the TimerTask’s portYIELDWITHINAPI() function call, then resume the application. It does not crash. So my guess is that this might due to certain time sequence. But I could not find the root cause of it. Any thoughts? Thanks.