[V1] gdbstub: gdb support for suspended state

Commit Message

Steven Sistare Nov. 2, 2020, 4:32 p.m. UTC

Modify the gdb server so a continue command appears to resume execution
when in RUN_STATE_SUSPENDED.  Do not print the next gdb prompt, but do not
actually resume instruction fetch.  While in this "fake" running mode, a
ctrl-C returns the user to the gdb prompt.

Signed-off-by: Steve Sistare <[e-mail]>
---
 gdbstub.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Patch

diff --git a/gdbstub.c b/gdbstub.c
index f3a318c..2f0d9ff 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -461,7 +461,9 @@  static inline void gdb_continue(void)
 #else
     if (!runstate_needs_reset()) {
         trace_gdbstub_op_continue();
-        vm_start();
+        if (!runstate_check(RUN_STATE_SUSPENDED)) {
+            vm_start();
+        }
     }
 #endif
 }
@@ -490,7 +492,7 @@  static int gdb_continue_partial(char *newstates)
     int flag = 0;
 
     if (!runstate_needs_reset()) {
-        if (vm_prepare_start()) {
+        if (!runstate_check(RUN_STATE_SUSPENDED) && vm_prepare_start()) {
             return 0;
         }
 
@@ -2835,6 +2837,9 @@  static void gdb_read_byte(uint8_t ch)
         /* when the CPU is running, we cannot do anything except stop
            it when receiving a char */
         vm_stop(RUN_STATE_PAUSED);
+    } else if (runstate_check(RUN_STATE_SUSPENDED) && ch == 3) {
+        /* Received ctrl-c from gdb */
+        gdb_vm_state_change(0, 0, RUN_STATE_PAUSED);
     } else
 #endif
     {
@@ -3282,6 +3287,8 @@  static void gdb_sigterm_handler(int signal)
 {
     if (runstate_is_running()) {
         vm_stop(RUN_STATE_PAUSED);
+    } else if (runstate_check(RUN_STATE_SUSPENDED)) {
+        gdb_vm_state_change(0, 0, RUN_STATE_PAUSED);
     }
 }
 #endif