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/*
* Copyright (c) 1995-1994 The University of Utah and
* the Computer Systems Laboratory at the University of Utah (CSL).
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software is hereby
* granted provided that (1) source code retains these copyright, permission,
* and disclaimer notices, and (2) redistributions including binaries
* reproduce the notices in supporting documentation, and (3) all advertising
* materials mentioning features or use of this software display the following
* acknowledgement: ``This product includes software developed by the
* Computer Systems Laboratory at the University of Utah.''
*
* THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
* IS" CONDITION. THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
* ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* CSL requests users of this software to return to csl-dist@cs.utah.edu any
* improvements that they make and grant CSL redistribution rights.
*
* Author: Bryan Ford, University of Utah CSL
*/
#include <mach/machine/code16.h>
#include <mach/machine/vm_types.h>
#include "i16_dos.h"
#include "config.h"
/* These aren't static because vcpi and dpmi code need to grab DOS memory
before we've switched to protected mode and memory has been collected. */
vm_offset_t dos_mem_phys_free_mem;
vm_size_t dos_mem_phys_free_size;
CODE32
void dos_mem_collect(void)
{
if (dos_mem_phys_free_mem)
{
phys_mem_add(dos_mem_phys_free_mem, dos_mem_phys_free_size);
dos_mem_phys_free_mem = 0;
}
}
CODE16
void i16_dos_mem_check()
{
unsigned short paras = 0xf000;
int dos_mem_seg;
/* Allocate as big a chunk of memory as we can find. */
do
{
if (paras == 0)
return;
dos_mem_seg = i16_dos_alloc(¶s);
}
while (dos_mem_seg < 0);
dos_mem_phys_free_mem = dos_mem_seg << 4;
dos_mem_phys_free_size = paras << 4;
#ifdef ENABLE_CODE_CHECK
i16_code_copy();
#endif
}
#ifdef ENABLE_CODE_CHECK
/* Big humongo kludge to help in finding random code-trashing bugs.
We copy the entire text segment upon initialization,
and then check it later as necessary. */
#include <mach/machine/proc_reg.h>
#include "vm_param.h"
extern char etext[], i16_entry_2[];
static int code_copy_seg;
static int i16_code_copy()
{
int text_size = (int)etext & ~0xf;
int i;
if (dos_mem_phys_free_size < text_size)
return;
code_copy_seg = dos_mem_phys_free_mem >> 4;
dos_mem_phys_free_mem += text_size;
dos_mem_phys_free_size -= text_size;
set_fs(code_copy_seg);
for (i = 0; i < text_size; i += 4)
asm volatile("
movl (%%ebx),%%eax
movl %%eax,%%fs:(%%ebx)
" : : "b" (i) : "eax");
}
void i16_code_check(int dummy)
{
int text_size = (int)etext & ~0xf;
int i, old, new;
int found = 0;
if (!code_copy_seg)
return;
set_fs(code_copy_seg);
for (i = (int)i16_entry_2; i < text_size; i += 4)
{
asm volatile("
movl (%%ebx),%%eax
movl %%fs:(%%ebx),%%ecx
" : "=a" (new), "=c" (old) : "b" (i));
if (old != new)
{
found = 1;
i16_writehexw(i);
i16_putchar(' ');
i16_writehexl(old);
i16_putchar(' ');
i16_writehexl(new);
i16_putchar('\r');
i16_putchar('\n');
}
}
if (found)
{
code_copy_seg = 0;
i16_writehexl((&dummy)[-1]);
i16_die(" DOS extender code trashed!");
}
}
CODE32
void code_check(int dummy)
{
int text_size = (int)etext & ~0xf;
unsigned char *new = 0, *old = (void*)phystokv(code_copy_seg*16);
int found = 0;
int i;
if (!code_copy_seg)
return;
for (i = (int)i16_entry_2; (i < text_size) && (found < 10); i++)
{
/* In several places we have to self-modify an int instruction,
or the segment value in an absolute long jmp instruction,
so ignore any changes preceded by those opcodes. */
if ((new[i] != old[i])
&& (old[i-1] != 0xcd)
&& (old[i-6] != 0xea))
{
if (!found)
{
found = 1;
about_to_die(1);
}
printf("%08x addr %04x was %02x now %02x\n",
(&dummy)[-1], i, old[i], new[i]);
}
}
if (found)
{
code_copy_seg = 0;
die("%08x DOS extender code trashed!", (&dummy)[-1]);
}
}
CODE16
#endif ENABLE_CODE_CHECK
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