Cortex M Hardfault Handler

hardfault.c

// A HardFault handler to make life easier when debugging
// See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0553a/Cihcfefj.html

// The smol version
void HardFault_Handler(void) {   
    SCB_Type* scb = SCB;
    (void*)scb;
    __asm("BKPT #0");
    while(1);
}

// The overly helpful version
void HardFault_Handler(void) {
    
    // Grab an instance of the SCB so we can `p/x *scb` from the debugger
    SCB_Type* scb = SCB;
    (void*)scb;

    // Identify hardfault type
    if (SCB->HFSR & SCB_HFSR_FORCED_Msk) {
        // Forced hardfault
        
        // Copy faults for easy debugging
        size_t mmu_fault   = (SCB->CFSR >> 0) & 0xFF;
        size_t bus_fault   = (SCB->CFSR >> 8) & 0xFF;
        size_t usage_fault = (SCB->CFSR >> 16) & 0xFFFF;
        
         // Check for memory manger faults
        if(SCB->CFSR & SCB_CFSR_MMARVALID_Msk)       __asm("BKPT #0");
        if(SCB->CFSR & SCB_CFSR_MLSPERR_Msk)         __asm("BKPT #0");
        if(SCB->CFSR & SCB_CFSR_MSTKERR_Msk)         __asm("BKPT #0");
        if(SCB->CFSR & SCB_CFSR_MUNSTKERR_Msk)       __asm("BKPT #0");
        if(SCB->CFSR & SCB_CFSR_DACCVIOL_Msk)        __asm("BKPT #0");
        if(SCB->CFSR & SCB_CFSR_IACCVIOL_Msk)        __asm("BKPT #0");

        // Check for bus faults
        if (SCB->CFSR & SCB_CFSR_BFARVALID_Msk)     __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_LSPERR_Msk)        __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_STKERR_Msk)        __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_UNSTKERR_Msk)      __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_IMPRECISERR_Msk)   __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_PRECISERR_Msk)     __asm("BKPT #0");
        if (SCB->CFSR & SCB_CFSR_IBUSERR_Msk)       __asm("BKPT #0");

        // Check for usage faults
        if (SCB->CFSR & SCB_CFSR_DIVBYZERO_Msk)     __asm("BKPT 0");
        if (SCB->CFSR & SCB_CFSR_UNALIGNED_Msk)     __asm("BKPT 0");
        if (SCB->CFSR & SCB_CFSR_NOCP_Msk)          __asm("BKPT 0");
        if (SCB->CFSR & SCB_CFSR_INVPC_Msk)         __asm("BKPT 0");
        if (SCB->CFSR & SCB_CFSR_INVSTATE_Msk)      __asm("BKPT 0");
        if (SCB->CFSR & SCB_CFSR_UNDEFINSTR_Msk)    __asm("BKPT 0");

        __asm("BKPT #0");

    } else if (SCB->HFSR & SCB_HFSR_VECTTBL_Msk) {
        // Vector table bus fault

        __asm("BKPT #0");
    }

    __asm("BKPT #0");
    while(1);
}