libdebugger: ARM fixes for Cortex-A8 and ARM mode.

- Fix destorying the target and thread parts.
- Fix the ARM backend to support Cortex-A8 and ARM mode code.
- Use the DBGDSCR interrupt mask when single stepping.
- Use the DBGDSCR method of entry to debug mode to filter the
  execptions.
- Add support for BSPs to control the ARM backend.

cpukit/Makefile.am

@@ -1882,6 +1882,7 @@ project_lib_LIBRARIES += libdebugger.a
 
 libdebugger_a_SOURCES =
 libdebugger_a_SOURCES += libdebugger/rtems-debugger-block.c
+libdebugger_a_SOURCES += libdebugger/rtems-debugger-bsp.c
 libdebugger_a_SOURCES += libdebugger/rtems-debugger-cmd.c
 libdebugger_a_SOURCES += libdebugger/rtems-debugger-remote.c
 libdebugger_a_SOURCES += libdebugger/rtems-debugger-remote-tcp.c

cpukit/include/rtems/debugger/rtems-debugger-bsp.h

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2019 Chris Johns <chrisj@rtems.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Debugger BSP support.
+ */
+
+#ifndef _RTEMS_DEBUGGER_BSP_h
+#define _RTEMS_DEBUGGER_BSP_h
+
+#include <rtems/rtems-debugger.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * ARM
+ */
+
+/**
+ * Debug registers
+ *
+ * Return the debugger registers for you BSP if the SoC requires memory mapped
+ * registers and the DBGDRAR and DBGDSAR are not support or return 0. This
+ * function is provided in the ARM backend and declared weak.
+ */
+void* rtems_debugger_arm_debug_registers(void);
+
+/**
+ * Configure the debug interface.
+ *
+ * Some ARM devices need special configurations to enable the debugging
+ * hardware. The device are often locked down for securty reasons and
+ * the debug hardware in the ARM needs to be enabled (asserting DBGEN).
+ */
+bool rtems_debugger_arm_debug_configure(void);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif

cpukit/libdebugger/rtems-debugger-bsp.c

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2019 Chris Johns <chrisj@rtems.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/debugger/rtems-debugger-bsp.h>
+
+void* rtems_debugger_arm_debug_registers(void) __attribute__ ((weak));
+bool rtems_debugger_arm_debug_configure(void) __attribute__ ((weak));
+
+void*
+rtems_debugger_arm_debug_registers(void)
+{
+  return NULL;
+}
+
+bool
+rtems_debugger_arm_debug_configure(void)
+{
+  return true;
+}

cpukit/libdebugger/rtems-debugger-server.c

@@ -1704,13 +1704,13 @@ rtems_debugger_session(void)
 
   r = rtems_debugger_target_create();
   if (r < 0) {
-    rtems_debugger_thread_destroy();
     rtems_debugger_unlock();
     return r;
   }
 
   r = rtems_debugger_thread_create();
   if (r < 0) {
+    rtems_debugger_target_destroy();
     rtems_debugger_unlock();
     return r;
   }
@@ -1725,8 +1725,8 @@ rtems_debugger_session(void)
                                  0,
                                  &rtems_debugger->events_task);
   if (r < 0) {
-    rtems_debugger_target_destroy();
     rtems_debugger_thread_destroy();
+    rtems_debugger_target_destroy();
     rtems_debugger_unlock();
     return r;
   }

cpukit/libdebugger/rtems-debugger-threads.c

@@ -362,6 +362,7 @@ rtems_debugger_thread_system_resume(bool detaching)
         rtems_debugger_thread* thread = &current[i];
         rtems_status_code      sc;
         int                    rr;
+        bool                   has_exception;
         /*
          * Check if resuming, which can be continuing, a step, or stepping a
          * range.
@@ -380,11 +381,13 @@ rtems_debugger_thread_system_resume(bool detaching)
                 r = rr;
             }
           }
+          has_exception =
+            rtems_debugger_thread_flag(thread,
+                                       RTEMS_DEBUGGER_THREAD_FLAG_EXCEPTION);
           if (rtems_debugger_verbose())
-            rtems_debugger_printf("rtems-db: sys:    : resume: 0x%08" PRIx32 "\n",
-                                  thread->id);
-          if (rtems_debugger_thread_flag(thread,
-                                         RTEMS_DEBUGGER_THREAD_FLAG_EXCEPTION)) {
+            rtems_debugger_printf("rtems-db: sys:    : resume: 0x%08" PRIx32 " %c\n",
+                                  thread->id, has_exception ? 'E' : ' ');
+          if (has_exception) {
               rtems_debugger_target_exception_thread_resume(thread);
           } else {
               sc = rtems_task_resume(thread->id);