//-------------------------------------------------------------------
//	cr3.c
//
//	This module creates a pseudo-file named 'cr3' in the '/proc'
//	directory which allows an application to obtain the physical 
//	address of its page-directory.  Using this information, with 
//	our 'ram.c' device-driver installed, it becomes possible for 
//	this application to locate, and to read in, its page-tables.
//
//	NOTE: Developed and tested with Linux kernel version 2.4.20.
//
//	programmer: ALLAN CRUSE
//	written on: 24 APR 2003
//	revised on: 27 OCT 2004 -- for Linux kernel version 2.4.26
//-------------------------------------------------------------------

#include <linux/module.h>	// for init_module() 
#include <linux/proc_fs.h>	// for create_proc_read_entry() 

#define	SUCCESS	0

static char modname[] = "cr3";

static int my_proc_read( char *buf, char **start, off_t off,
					int count, int *eof, void *data )
{
	int	cr3, len;
       
	asm(" movl %%cr3, %%eax \n movl %%eax, %0 " : "=m" (cr3) );
	len = sprintf( buf, "cr3=%08X\n", cr3 );
	*eof = 1;
	return	len;
}


void cleanup_module( void )
{
	remove_proc_entry( modname, NULL );
	printk( "<1>Removing \'%s\' module\n", modname );
}


int init_module( void )
{
	printk( "<1>\nInstalling \'%s\' module\n", modname );
	create_proc_read_entry( modname, 0, NULL, my_proc_read, NULL );
	return	SUCCESS;
}

MODULE_LICENSE("GPL");