#include<stdio.h>
#include <sys/mman.h>
#include <syscall.h>
#include <errno.h>

int main()
{
	int fd,i;
	unsigned char * mem1, *mem2;
	const int size = 2 * 1024 * 1024;
	unsigned long addrphys = 254 * 1024 * 1024;
	
	mlockall(MCL_CURRENT| MCL_FUTURE);
	
	if ((fd = open("/dev/mem", 02) ) < 0) 
	{
		printf("can't open /dev/mem \n");
		exit (-1);
	}
	
	mem1 = (unsigned char *) mmap((void *)0,size ,PROT_READ | PROT_WRITE,MAP_SHARED , fd, addrphys);
	if (mem1)
		memset(mem1,0, size-1);
	printf("%d",(int) mem1);
	 if (mem1)
	{
		for (i=0; i < (size-1); i++)
		{
			printf("%x ", *(mem1 +i));
		}
		printf("\n\r");
	}
	
	munmap((void *)mem1,size );
	close(fd);
}