diff options
Diffstat (limited to 'i386/dos/i16/i16_dos_mem.c')
| -rw-r--r-- | i386/dos/i16/i16_dos_mem.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/i386/dos/i16/i16_dos_mem.c b/i386/dos/i16/i16_dos_mem.c new file mode 100644 index 0000000..e78398d --- /dev/null +++ b/i386/dos/i16/i16_dos_mem.c @@ -0,0 +1,182 @@ +/* + * 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 |