l4/pkg/plr/server/src/fault_handlers/debugger.cc

   1 /*
   2  * debugger.cc --
   3  *
   4  *     Implementation of a tiny debugger without any GDB features.
   5  *
   6  *     Currently this debugger allows to configure an address in the Romain ini file,
   7  *     (simplegdb:singlestep). It will then place a breakpoint (0xCC) on this address
   8  *     and once this BP is hit, start single-stepping from this point on.
   9  *
  10  * (c) 2011-2013 Björn Döbel <doebel@os.inf.tu-dresden.de>,
  11  *     economic rights: Technische Universität Dresden (Germany)
  12  * This file is part of TUD:OS and distributed under the terms of the
  13  * GNU General Public License 2.
  14  * Please see the COPYING-GPL-2 file for details.
  15  */
  16
  17 #include "../log"
  18 #include "../app_loading"
  19 #include "../emulation"
  20 #include "../configuration"
  21
  22 #include "debugging.h"
  23 #include "observers.h"
  24
  25 Romain::SimpleDebugObserver::SimpleDebugObserver()
  26         : _int1_seen(0)
  27 {
  28         _bp = new Breakpoint(determine_address());
  29 }
  30
  31 /*****************************************************************
  32  *                      Debugging stuff                          *
  33  *****************************************************************/
  34 void Romain::SimpleDebugObserver::startup_notify(Romain::App_instance *i,
  35                                                  Romain::App_thread *,
  36                                                  Romain::Thread_group *,
  37                                                  Romain::App_model *am)
  38 {
  39         if (_bp->address() != ~0UL) {
  40                 _bp->activate(i, am);
  41                 DEBUG() << "Activated breakpoint in instance " << i->id()
  42                                 << " @ address " << std::hex << _bp->address();
  43                 enter_kdebug();
  44         }
  45 }
  46
  47
  48 void Romain::SimpleDebugObserver::status() const { }
  49
  50 Romain::Observer::ObserverReturnVal
  51 Romain::SimpleDebugObserver::notify(Romain::App_instance *i,
  52                                     Romain::App_thread *t,
  53                                     Romain::Thread_group *,
  54                                     Romain::App_model *am)
  55 {
  56         switch(t->vcpu()->r()->trapno) {
  57                 case 1:
  58                         Romain::InstructionPrinter(am->rm()->remote_to_local(t->vcpu()->r()->ip, 0),
  59                                                    t->vcpu()->r()->ip);
  60                         ++_int1_seen;
  61                         t->vcpu()->print_state();
  62                         INFO() << "INT1 seen: " << _int1_seen;
  63                         enter_kdebug("single step exception");
  64                         break;
  65                 case 3:
  66                         DEBUG() << "INT3 @ " << std::hex << t->vcpu()->r()->ip
  67                                     << " addr = " << _bp->address();
  68                         if (_bp->was_hit(t)) {
  69                                 DEBUG() << "refs: " << _bp->refs();
  70                                 t->vcpu()->r()->ip -= 1; // revert int3
  71                                 t->vcpu()->r()->flags |= TrapFlag;
  72                                 _bp->deactivate(i, am);
  73                                 if (_bp->refs() == 0)
  74                                         delete _bp;
  75                         }
  76                         break;
  77                 default:
  78                         break;
  79         }
  80
  81         return Romain::Observer::Continue;
  82 }