diff -r bd207697f0c7 xen/arch/x86/boot/mkelf32.c
--- a/xen/arch/x86/boot/mkelf32.c	Wed Oct 18 13:43:35 2006 +0100
+++ b/xen/arch/x86/boot/mkelf32.c	Tue Oct 17 16:39:13 2006 +0200
@@ -90,9 +90,15 @@ static Elf32_Shdr out_shdr[] = {
     }
 };
 
+#ifndef swap16
 #define swap16(_v) ((((u16)(_v)>>8)&0xff)|(((u16)(_v)&0xff)<<8))
+#endif
+#ifndef swap32
 #define swap32(_v) (((u32)swap16((u16)(_v))<<16)|(u32)swap16((u32)((_v)>>16)))
+#endif
+#ifndef swap64
 #define swap64(_v) (((u64)swap32((u32)(_v))<<32)|(u64)swap32((u32)((_v)>>32)))
+#endif
 
 static int big_endian;
 
diff -r bd207697f0c7 xen/arch/x86/setup.c
--- a/xen/arch/x86/setup.c	Wed Oct 18 13:43:35 2006 +0100
+++ b/xen/arch/x86/setup.c	Tue Oct 17 16:39:13 2006 +0200
@@ -16,6 +16,7 @@
 #include <xen/percpu.h>
 #include <xen/hypercall.h>
 #include <xen/keyhandler.h>
+#include <xen/guard.h>
 #include <public/version.h>
 #include <asm/bitops.h>
 #include <asm/smp.h>
@@ -625,6 +626,8 @@ void __init __start_xen(multiboot_info_t
                         cmdline) != 0)
         panic("Could not set up DOM0 guest OS\n");
 
+    init_guard();
+
     /* Scrub RAM that is still free and so may go to an unprivileged domain. */
     scrub_heap_pages();
 
diff -r bd207697f0c7 xen/common/Makefile
--- a/xen/common/Makefile	Wed Oct 18 13:43:35 2006 +0100
+++ b/xen/common/Makefile	Tue Oct 17 16:39:13 2006 +0200
@@ -5,6 +5,7 @@ obj-y += elf.o
 obj-y += elf.o
 obj-y += event_channel.o
 obj-y += grant_table.o
+obj-y += guard.o
 obj-y += kernel.o
 obj-y += keyhandler.o
 obj-y += lib.o
diff -r bd207697f0c7 xen/common/guard.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/common/guard.c	Tue Oct 17 16:39:13 2006 +0200
@@ -0,0 +1,34 @@
+
+#include <xen/lib.h>
+
+long __guard[8];
+
+void __stack_smash_handler(char [], int __attribute__((unused)));
+
+void
+__stack_smash_handler(char func[], int damaged)
+{
+        panic("smashed stack in %s", func);
+}
+
+
+void init_guard(void)
+{
+	volatile long newguard[8];
+	int i;
+
+	/* XXX newguard is intended to get filled with random values.
+	 * But there's nothing to use, so this is just something
+	 * out of my head :) */
+	newguard[0] = 103958;
+	newguard[1] = 3505;
+	newguard[2] = 75601;
+	newguard[3] = 35703;
+	newguard[4] = 94;
+	newguard[5] = 721;
+	newguard[6] = 3094;
+	newguard[7] = 217;
+
+	for (i = sizeof(__guard) / sizeof(__guard[0]) - 1; i; i--)
+		__guard[i] = newguard[i];
+}
diff -r bd207697f0c7 xen/include/xen/guard.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/include/xen/guard.h	Tue Oct 17 16:39:13 2006 +0200
@@ -0,0 +1,3 @@
+
+
+void init_guard(void);
+