Added null trap code for debugging. (Must be included by adding

--nulltrap to the make target at the moment.)

src/arch/i386/core/nulltrap.c

@@ -0,0 +1,48 @@
+#include <stdint.h>
+#include <vsprintf.h>
+
+__attribute__ (( noreturn, section ( ".text.null_trap" ) ))
+void null_function_trap ( void ) {
+
+	/* 128 bytes of NOPs; the idea of this is that if something
+	 * dereferences a NULL pointer and overwrites us, we at least
+	 * have some chance of still getting to execute the printf()
+	 * statement.
+	 */
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+	__asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
+
+	printf ( "NULL method called from %p\n", 
+		 __builtin_return_address ( 0 ) );
+	while ( 1 ) {}
+}

src/arch/i386/scripts/i386.lds

@@ -117,6 +117,7 @@ SECTIONS {
 
     .text : AT ( _textdata_load_offset + __text ) {
 	__text = .;
+	*(.text.null_trap)
 	*(.text)
 	*(.text.*)
     } = 0x9090