johnsonjh/duma

/*
 * KDUMA - Kernel Mode Red-Zone memory allocator.
 * Copyright (C) 2006 Michael Eddington <meddington@gmail.com>
 * Copyright (C) 2006 Eric Rachner <eric@rachner.us>
 * Copyright (C) 2002-2005 Hayati Ayguen <h_ayguen@web.de>, Procitec GmbH
 * Copyright (C) 1987-1999 Bruce Perens <bruce@perens.com>
 * License: GNU GPL (GNU General Public License, see COPYING-GPL)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/* $Id$ */

#ifndef DUMA_PAGING_H
#define DUMA_PAGING_H

#include "log.h"

/*
 * Lots of systems are missing the definition of PROT_NONE.
 */
#ifndef  PROT_NONE
#define  PROT_NONE  0
#endif

#ifndef size_t
#define size_t unsigned long
#endif

static caddr_t  startAddr = (caddr_t) 0;

/* Function: mprotectFailed
 *
 * Report that VirtualProtect or mprotect failed and abort
 * program execution.
 */
static void mprotectFailed(void)
{
    DUMA_Abort("mprotect() failed: %s", stringErrorReport());
}


/* Function: Page_Create
 *
 * Create memory.  Allocates actual memory. Uses
 * VirtualAlloc on windows and mmap on unix.
 *
 * flags - Passed along from kmalloc (GFP_ATOMIC and the like)
 *
 * See Also:
 *    <Page_Delete>
 */
static void *
Page_Create(size_t size, int exitonfail, int printerror, int flags)
{
    caddr_t    allocation;

    unsigned long numPages = size/DUMA_PAGE_SIZE;
    if( size % DUMA_AGE_SIZE )
        numPages++;

    unsigned long order = ilog2(numPages);

    allocation = __get_free_pages(flags, order);

    if ( allocation == 0 )
    {
        if ( exitonfail )
            DUMA_Abort("__get_fre_pages(%d, %d) failed: %s", flags, order, stringErrorReport());
        else if ( printerror )
            DUMA_Print("\nDUMA warning: __get_fre_pages(%d, %d) failed: %s", flags, order, stringErrorReport());
    }

    return (void *)allocation;
}


/* Function: Page_AllowAccess
 *
 * Allow memory access to allocated memory.
 *
 * See Also:
 *    <Page_DenyAccess>
 */
void Page_AllowAccess(void * address, size_t size)
{
    if ( mprotect((caddr_t)address, size, PROT_READ|PROT_WRITE) < 0 )
        mprotectFailed();
#endif
}


/* Function: Page_DenyAccess
 *
 * Deny access to allocated memory region.
 *
 * See Also:
 *    <Page_AllowAccess>
 */
static void Page_DenyAccess(void * address, size_t size)
{
    if ( mprotect((caddr_t)address, size, PROT_NONE) < 0 )
        mprotectFailed();
}

extern struct _DUMA_Slot;


/* Function: Page_Delete
 *
 * Free's DUMA allocated memory.  This is the real deal, make sure
 * the page is no longer in our slot list first!
 *
 * See Also:
 *    <Page_Create>
 */
static void Page_Delete(void * address, size_t size)
{

    unsigned long numPages = size/DUMA_PAGE_SIZE;
    if( size % DUMA_AGE_SIZE )
        numPages++;

    unsigned long order = ilog2(numPages);
    __free_pages(address, size);

}


/* Function: Page_Size
 *
 * Retrieve page size.
 */
static size_t
Page_Size(void)
{
    return getpagesize();
}


#endif /* DUMA_PAGING_H */