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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <asm/memory.h>
#define MMUHACK_MINOR 225
#define DEVICE_NAME "mmuhack"
#if __GNUC__ == 3
#include <linux/version.h>
static const char __module_kernel_version_gcc3[] __attribute__((__used__)) __attribute__((section(".modinfo"))) =
"kernel_version=" UTS_RELEASE;
#endif
static ssize_t mmuhack_open(struct inode *inode, struct file *filp)
{
unsigned int *pgtable;
unsigned int *cpt;
int i, j;
int ttb;
int ret = -EFAULT;
// get the pointer to the translation table base...
asm volatile(
"stmdb sp!, {r0}\n\t"
"mrc p15, 0, r0, c2, c0, 0\n\t"
"mov %0, r0\n\t"
"ldmia sp!, {r0}\n\t": "=r"(ttb)
);
pgtable = __va(ttb);
for (i = 0; i < 4096; i ++) if ( (pgtable[i] & 3) == 1 ) {
cpt = __va(pgtable[i] & 0xfffffc00);
for (j = 0; j < 256; j ++) {/*
if ( (cpt[j] & 0xfe00000f) == 0x02000002 ) {
// set C and B bits in upper 32MB memory area...
printk("Set C&B bits %08x\n",cpt[j]);
cpt[j] |= 0xFFC;
ret = 0;
}
*/
if (((cpt[j] & 0xff000000) == 0x02000000) && ((cpt[j] & 12)==0) )
{
//printk("Set C&B bits %08x\n",cpt[j]);
cpt[j] |= 0xFFC;
}
//if ((a>=0x31 && a<=0x36) && ((cpt[i] & 12)==0))
if (((cpt[j] & 0xff000000) == 0x03000000) && ((cpt[j] & 12)==0))
{
//printk("Set C&B bits %08x\n",cpt[j]);
//printf("SDL c and b bits not set, overwriting\n");
cpt[j] |= 0xFFC;
}
}
}
// drain the write buffer and flush the tlb caches...
asm volatile(
"stmdb sp!, {r0}\n\t"
"mov r0, #0\n\t"
"mcr 15, 0, r0, cr7, cr10, 4\n\t"
"mcr 15, 0, r0, cr8, cr7, 0\n\t"
"ldmia sp!, {r0}\n\t"
);
if (ret == 0)
printk("MMU hack applied.\n");
return 0;
}
static struct file_operations mmuhack_fops = {
owner: THIS_MODULE,
open: mmuhack_open,
};
static struct miscdevice mmuhack = {
MMUHACK_MINOR, DEVICE_NAME, &mmuhack_fops
};
static int __init mmuhack_init(void)
{
misc_register(&mmuhack);
/*
printk("MMSP2 MMU Hack module.\n");
*/
return 0;
}
static void __exit mmuhack_exit(void)
{
misc_deregister(&mmuhack);
/*
printk(KERN_ALERT "MMU Hack module removed.\n");
*/
}
module_init(mmuhack_init);
module_exit(mmuhack_exit);
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