rem: int flags = disable_interrupts();
add: cpu_status state = disable_interrupts();
context: dbg_putch(char c){	char ret;	int flags = disable_interrupts();	acquire_spinlock(&dbg_spinlock);	if (serial_debug_on)		ret = arch_dbg_con_putch(c);	else		ret = c;	release_spinlock(&dbg_spinlock);	restore_interrupts(flags);	return ret;}