CONFIG_ETRAX_GPIO is not available for thedefaultarchitecture x86.
Result is shown for architecture cris

GPIO support

modulename: gpio.ko

configname: CONFIG_ETRAX_GPIO

Linux Kernel Configuration
└─>GPIO support
In linux kernel since version 2.6.12  
Enables the ETRAX general port device (major 120, minors 0 and 1).
You can use this driver to access the general port bits. It supports
these ioctl's:
#include <linux/etraxgpio.h>
fd = open("/dev/gpioa", O_RDWR); // or /dev/gpiob
ioctl(fd, _IO(ETRAXGPIO_IOCTYPE, IO_SETBITS), bits_to_set);
ioctl(fd, _IO(ETRAXGPIO_IOCTYPE, IO_CLRBITS), bits_to_clear);
val = ioctl(fd, _IO(ETRAXGPIO_IOCTYPE, IO_READBITS), NULL);
Remember that you need to setup the port directions appropriately in
the General configuration.

source code: