Initial source

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 00000000..e78398db
--- /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(&paras);
+	}
+	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