mirror of
https://github.com/scummvm/scummvm.git
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125 lines
3.1 KiB
C
125 lines
3.1 KiB
C
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <asm/memory.h>
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#define MMUHACK_MINOR 225
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#define DEVICE_NAME "mmuhack"
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#if __GNUC__ == 3
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#include <linux/version.h>
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static const char __module_kernel_version_gcc3[] __attribute__((__used__)) __attribute__((section(".modinfo"))) =
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"kernel_version=" UTS_RELEASE;
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#endif
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static ssize_t mmuhack_open(struct inode *inode, struct file *filp)
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{
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unsigned int *pgtable;
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unsigned int *cpt;
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int i, j;
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int ttb;
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int ret = -EFAULT;
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// get the pointer to the translation table base...
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asm volatile(
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"stmdb sp!, {r0}\n\t"
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"mrc p15, 0, r0, c2, c0, 0\n\t"
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"mov %0, r0\n\t"
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"ldmia sp!, {r0}\n\t": "=r"(ttb)
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);
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pgtable = __va(ttb);
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for (i = 0; i < 4096; i ++) if ( (pgtable[i] & 3) == 1 ) {
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cpt = __va(pgtable[i] & 0xfffffc00);
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for (j = 0; j < 256; j ++) {/*
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if ( (cpt[j] & 0xfe00000f) == 0x02000002 ) {
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// set C and B bits in upper 32MB memory area...
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printk("Set C&B bits %08x\n",cpt[j]);
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cpt[j] |= 0xFFC;
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ret = 0;
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}
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*/
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if (((cpt[j] & 0xff000000) == 0x02000000) && ((cpt[j] & 12)==0) )
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{
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//printk("Set C&B bits %08x\n",cpt[j]);
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cpt[j] |= 0xFFC;
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}
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//if ((a>=0x31 && a<=0x36) && ((cpt[i] & 12)==0))
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if (((cpt[j] & 0xff000000) == 0x03000000) && ((cpt[j] & 12)==0))
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{
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//printk("Set C&B bits %08x\n",cpt[j]);
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//printf("SDL c and b bits not set, overwriting\n");
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cpt[j] |= 0xFFC;
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}
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}
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}
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// drain the write buffer and flush the tlb caches...
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asm volatile(
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"stmdb sp!, {r0}\n\t"
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"mov r0, #0\n\t"
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"mcr 15, 0, r0, cr7, cr10, 4\n\t"
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"mcr 15, 0, r0, cr8, cr7, 0\n\t"
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"ldmia sp!, {r0}\n\t"
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);
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if (ret == 0)
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printk("MMU hack applied.\n");
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return 0;
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}
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static struct file_operations mmuhack_fops = {
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owner: THIS_MODULE,
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open: mmuhack_open,
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};
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static struct miscdevice mmuhack = {
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MMUHACK_MINOR, DEVICE_NAME, &mmuhack_fops
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};
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static int __init mmuhack_init(void)
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{
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misc_register(&mmuhack);
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/*
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printk("MMSP2 MMU Hack module.\n");
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*/
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return 0;
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}
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static void __exit mmuhack_exit(void)
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{
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misc_deregister(&mmuhack);
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/*
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printk(KERN_ALERT "MMU Hack module removed.\n");
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*/
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}
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module_init(mmuhack_init);
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module_exit(mmuhack_exit);
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