runtime/arch/mips/fault_handler_mips.cc [58:120]:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  if (overflow_addr == fault_addr) {
    *out_method = reinterpret_cast<ArtMethod*>(sc->sc_regs[4]);  // A0 register
  } else {
    // The method is at the top of the stack.
    *out_method = *reinterpret_cast<ArtMethod**>(*out_sp);
  }

  // Work out the return PC.  This will be the address of the instruction
  // following the faulting ldr/str instruction.

  VLOG(signals) << "pc: " << std::hex
      << static_cast<void*>(reinterpret_cast<uint8_t*>(sc->sc_pc));

  *out_return_pc = sc->sc_pc + 4;
}

bool NullPointerHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info ATTRIBUTE_UNUSED,
                                void* context) {
  // The code that looks for the catch location needs to know the value of the
  // PC at the point of call.  For Null checks we insert a GC map that is immediately after
  // the load/store instruction that might cause the fault.

  struct ucontext *uc = reinterpret_cast<struct ucontext*>(context);
  struct sigcontext *sc = reinterpret_cast<struct sigcontext*>(&uc->uc_mcontext);

  sc->sc_regs[31] = sc->sc_pc + 4;      // RA needs to point to gc map location
  sc->sc_pc = reinterpret_cast<uintptr_t>(art_quick_throw_null_pointer_exception);
  sc->sc_regs[25] = sc->sc_pc;          // make sure T9 points to the function
  VLOG(signals) << "Generating null pointer exception";
  return true;
}

bool SuspensionHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info ATTRIBUTE_UNUSED,
                               void* context ATTRIBUTE_UNUSED) {
  return false;
}

// Stack overflow fault handler.
//
// This checks that the fault address is equal to the current stack pointer
// minus the overflow region size (16K typically). The instruction that
// generates this signal is:
//
// lw zero, -16384(sp)
//
// It will fault if sp is inside the protected region on the stack.
//
// If we determine this is a stack overflow we need to move the stack pointer
// to the overflow region below the protected region.

bool StackOverflowHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info, void* context) {
  struct ucontext* uc = reinterpret_cast<struct ucontext*>(context);
  struct sigcontext *sc = reinterpret_cast<struct sigcontext*>(&uc->uc_mcontext);
  VLOG(signals) << "stack overflow handler with sp at " << std::hex << &uc;
  VLOG(signals) << "sigcontext: " << std::hex << sc;

  uintptr_t sp = sc->sc_regs[29];  // SP register
  VLOG(signals) << "sp: " << std::hex << sp;

  uintptr_t fault_addr = reinterpret_cast<uintptr_t>(info->si_addr);  // BVA addr
  VLOG(signals) << "fault_addr: " << std::hex << fault_addr;
  VLOG(signals) << "checking for stack overflow, sp: " << std::hex << sp <<
    ", fault_addr: " << fault_addr;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -



runtime/arch/mips64/fault_handler_mips64.cc [58:120]:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  if (overflow_addr == fault_addr) {
    *out_method = reinterpret_cast<ArtMethod*>(sc->sc_regs[4]);  // A0 register
  } else {
    // The method is at the top of the stack.
    *out_method = *reinterpret_cast<ArtMethod**>(*out_sp);
  }

  // Work out the return PC.  This will be the address of the instruction
  // following the faulting ldr/str instruction.

  VLOG(signals) << "pc: " << std::hex
      << static_cast<void*>(reinterpret_cast<uint8_t*>(sc->sc_pc));

  *out_return_pc = sc->sc_pc + 4;
}

bool NullPointerHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info ATTRIBUTE_UNUSED,
                                void* context) {
  // The code that looks for the catch location needs to know the value of the
  // PC at the point of call.  For Null checks we insert a GC map that is immediately after
  // the load/store instruction that might cause the fault.

  struct ucontext *uc = reinterpret_cast<struct ucontext*>(context);
  struct sigcontext *sc = reinterpret_cast<struct sigcontext*>(&uc->uc_mcontext);

  sc->sc_regs[31] = sc->sc_pc + 4;      // RA needs to point to gc map location
  sc->sc_pc = reinterpret_cast<uintptr_t>(art_quick_throw_null_pointer_exception);
  sc->sc_regs[25] = sc->sc_pc;          // make sure T9 points to the function
  VLOG(signals) << "Generating null pointer exception";
  return true;
}

bool SuspensionHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info ATTRIBUTE_UNUSED,
                               void* context ATTRIBUTE_UNUSED) {
  return false;
}

// Stack overflow fault handler.
//
// This checks that the fault address is equal to the current stack pointer
// minus the overflow region size (16K typically). The instruction that
// generates this signal is:
//
// lw zero, -16384(sp)
//
// It will fault if sp is inside the protected region on the stack.
//
// If we determine this is a stack overflow we need to move the stack pointer
// to the overflow region below the protected region.

bool StackOverflowHandler::Action(int sig ATTRIBUTE_UNUSED, siginfo_t* info, void* context) {
  struct ucontext* uc = reinterpret_cast<struct ucontext*>(context);
  struct sigcontext *sc = reinterpret_cast<struct sigcontext*>(&uc->uc_mcontext);
  VLOG(signals) << "stack overflow handler with sp at " << std::hex << &uc;
  VLOG(signals) << "sigcontext: " << std::hex << sc;

  uintptr_t sp = sc->sc_regs[29];  // SP register
  VLOG(signals) << "sp: " << std::hex << sp;

  uintptr_t fault_addr = reinterpret_cast<uintptr_t>(info->si_addr);  // BVA addr
  VLOG(signals) << "fault_addr: " << std::hex << fault_addr;
  VLOG(signals) << "checking for stack overflow, sp: " << std::hex << sp <<
    ", fault_addr: " << fault_addr;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -