src/arch/i386/core/nulltrap.c

   1 #include <stdint.h>
   2 #include <stdio.h>
   3
   4 __attribute__ (( noreturn, section ( ".text.null_trap" ) ))
   5 void null_function_trap ( void ) {
   6         void *stack;
   7
   8         /* 128 bytes of NOPs; the idea of this is that if something
   9          * dereferences a NULL pointer and overwrites us, we at least
  10          * have some chance of still getting to execute the printf()
  11          * statement.
  12          */
  13         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  14         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  15         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  16         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  17         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  18         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  19         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  20         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  21         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  22         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  23         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  24         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  25         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  26         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  27         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  28         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  29         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  30         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  31         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  32         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  33         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  34         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  35         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  36         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  37         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  38         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  39         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  40         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  41         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  42         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  43         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  44         __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
  45
  46         __asm__ __volatile__ ( "movl %%esp, %0" : "=r" ( stack ) );
  47         printf ( "NULL method called from %p (stack %p)\n",
  48                  __builtin_return_address ( 0 ), stack );
  49         DBG_HD ( stack, 256 );
  50         while ( 1 ) {}
  51 }