//-------------------------------------------------------------------
//	mem64.c
//
//	This module creates a pseudo-file (named '/proc/mem64') that
//	shows a map of virtual memory use (based on 'level4' table). 
//
//	programmer: ALLAN CRUSE
//	written on: 22 JUN 2008
//	revised on: 23 APR 2009 -- for Linux kernel version 2.6.26.6
//-------------------------------------------------------------------

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

char modname[] = "mem64";
struct new_utsname  *uts;
unsigned long 	     cr3;

char title[] = "Linux memory-map for 64-bit kernel";

int 
my_info( char *buf, char **start, off_t off, int count, int *eof, void *data )
{
	unsigned long	*level4;
	int		i, len = 0;

	asm(" mov %%cr3, %%rax \n mov %%rax, cr3 " ::: "ax" );
	level4 = phys_to_virt( cr3 );
	
	len += sprintf( buf+len, "\n %54s \n", title );
	len += sprintf( buf+len, "\n\t\t CR3=%08lX ", cr3 );
	len += sprintf( buf+len, "---> Level_4=%p \n", level4 );
	for (i = 0; i < 512; i++)
		{
		int	prot = level4[i] & 0x7;
		prot = ( prot == 0 ) ? '-' : prot + '0';
		if ( (i % 64)==0 ) len += sprintf( buf+len, "\n  %03X ", i*8 );
		len += sprintf( buf+len, "%c", prot );
		}
	len += sprintf( buf+len, "\n" );

	len += sprintf( buf+len, "\n  Legend:" );
	len += sprintf( buf+len, " '7'=user-accessble   " );
	len += sprintf( buf+len, " '3'=supervisor-only   " );
	len += sprintf( buf+len, " '-'=not-present   " );
	len += sprintf( buf+len, "\n" );
	
	len += sprintf( buf+len, "\n      " );
	len += sprintf( buf+len, "Linux kernel-version %s ", uts->release );
	len += sprintf( buf+len, "on station \'%s\' \n", uts->nodename );
	len += sprintf( buf+len, "\n" );

	return	len;
}


static int __init mem64_init( void )
{
	printk( "<1>\nInstalling \'%s\' module\n", modname );

	uts = utsname();

	create_proc_read_entry( modname, 0, NULL, my_info, NULL );
	return	0;  //SUCCESS
}


static void __exit mem64_exit(void )
{
	remove_proc_entry( modname, NULL );

	printk( "<1>Removing \'%s\' module\n", modname );
}

module_init( mem64_init );
module_exit( mem64_exit );
MODULE_LICENSE("GPL");