AVR Freaks

int main(void)
{
	UART_Init0();
	uint8_t a ;
	uint8_t *p;
	p = &PORTB;

    
    while (1) 
    {
    }
}

I want to access the address of GPIO peripheral Registers, for that, I have written these lines of code. 

But on building the solution it shows error:       invalid conversion from 'volatile uint8_t* {aka volatile unsigned char*}' to 'uint8_t* {aka unsigned char*}' [-fpermissive]   

I am not able to make out what wrong am I doing, as PORTB corresponds to _SFR_IO8(0x05). 

the main thing which I want to do is to access the peripheral GPIO register by address instead of its naming Convention