Hi ARM, Hi ARM, hardfault_handler()

Hi ARM,

while developing code i am facing following issue.
Processor - ARM cortex M3.
Controller - lpc1778
we are developing code for UART3 ,
CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART3, ENABLE);
LPC_UART3->LCR = 0x83; /* 8 bit, 1 stop bit, no parity, enable DLAB */
LPC_UART3->DLL = divisor & 0xFF;
LPC_UART3->DLM = (divisor >> 8) & 0xFF;
LPC_UART3->FDR = (mulval << 4) | divval;
LPC_UART3->LCR &= ~0x80; /* Disable DLAB */
PINSEL_ConfigPin(0,0,2);//UART3 TX
PINSEL_ConfigPin(0,1,2);//UART3 RX
LPC_IOCON->P0_0 = (LPC_IOCON->P0_0 & ~0x7) | 0x02;
LPC_IOCON->P0_1 = (LPC_IOCON->P0_1 & ~0x7) | 0x02;
LPC_UART3->FCR = 1;
LPC_UART3->TER = 0x80;
if(interrupt)
{
LPC_UART3->FCR = 0x49; //Set FIFO Trigger to 4 characters and Enable DMA
LPC_UART3->IER = 0x01; //Enable Interrupts
/* preemption = 1, sub-priority = 1 */
NVIC_SetPriority(UART3_IRQn, ((0x01<<3)|0x01));
NVIC_EnableIRQ(UART3_IRQn);

and after this configuration i am calling a function i mention below

void BSP_UART3_Write_Char (U8 ch)
{
while ((LPC_UART3->LSR & 0x20) == 0);
LPC_UART3->THR = ch;
}

if i call this function , my code will hung up at hardfault_handler()
please help me how to solve this issue, and why i am getting this issue