//-------------------------------------------------------------------
//	gpd.c
//
//	This module creates a pseudo-file named 'gpd' in the /proc
//	directory which provides a way for application programs to 
//	access to the current task's Global Page Directory, though 
//	in raw binary format unsuitable for displaying with 'cat'.
//
//	NOTE: Written and tested with Linux kernel version 2.4.20.
//
//	programmer: ALLAN CRUSE
//	written on: 20 FEB 2003
//-------------------------------------------------------------------

#define	__KERNEL__
#define	  MODULE  

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

#define	SUCCESS	0

static char modname[] = "gpd";
static char buffer[ 4096 ];

static int my_proc_read( char *buf, char **start, off_t off,
			int count, int *eof, void *data )
{
	unsigned long	reg_cr3;
	void		*gpd;

	asm(" movl %%cr3, %%eax ; movl %%eax, %0 " : "=m" (reg_cr3) );
       	gpd = phys_to_virt( reg_cr3 );	
	memcpy( buffer, gpd, 4096 );
	*start = buffer;
	*eof = 1;
	return	4096;
}


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");