From 3312ab2087410fcc00d8ae17a68fa7563e0eec6e Mon Sep 17 00:00:00 2001
From: anjiahao <anjiahao@xiaomi.com>
Date: Mon, 25 Mar 2024 11:27:38 +0800
Subject: [PATCH] gdbstub:fix get thread rsp command crash

riscv-gdb/gdb/thread.c:1309: internal-error: void switch_to_thread(thread_info*): Assertion `thr != NULL' failed.

Signed-off-by: anjiahao <anjiahao@xiaomi.com>
---
 libs/libc/gdbstub/lib_gdbstub.c | 47 ++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git a/libs/libc/gdbstub/lib_gdbstub.c b/libs/libc/gdbstub/lib_gdbstub.c
index 433017f60c..4fd5c6a1a1 100644
--- a/libs/libc/gdbstub/lib_gdbstub.c
+++ b/libs/libc/gdbstub/lib_gdbstub.c
@@ -781,6 +781,39 @@ static int gdb_send_ok_packet(FAR struct gdb_state_s *state)
   return gdb_send_packet(state);
 }
 
+/****************************************************************************
+ * Name: gdb_send_signal_packet
+ *
+ * Description:
+ *   Send a signal packet (S AA).
+ *
+ * Input Parameters:
+ *   state   - The pointer to the GDB state structure.
+ *   signal  - The signal to send.
+ *
+ * Returned Value:
+ *   Zero on success.
+ *   Negative value on error.
+ *
+ ****************************************************************************/
+
+static int gdb_send_signal_packet(FAR struct gdb_state_s *state,
+                                  unsigned char signal)
+{
+  int ret;
+
+  state->pkt_buf[0] = 'S';
+  ret = gdb_bin2hex(&state->pkt_buf[1], sizeof(state->pkt_buf) - 1,
+                    &signal, 1);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  state->pkt_len = 1 + ret;
+  return gdb_send_packet(state);
+}
+
 /****************************************************************************
  * Name: gdb_send_error_packet
  *
@@ -1316,6 +1349,7 @@ static int gdb_is_thread_active(FAR struct gdb_state_s *state)
  *   Negative value on error.
  *
  * Note : Comand Format: Hg<id>
+ *                       Hc-<id>
  *        Rsponse Format: OK
  ****************************************************************************/
 
@@ -1325,12 +1359,19 @@ static int gdb_thread_context(FAR struct gdb_state_s *state)
   uintptr_t pid;
   int ret;
 
-  if (state->pkt_buf[1] != 'g')
+  if (state->pkt_buf[1] == 'g')
+    {
+      state->pkt_next += 2;
+    }
+  else if  (state->pkt_buf[1] == 'c')
+    {
+      state->pkt_next += 3;
+    }
+  else
     {
       return -EINVAL;
     }
 
-  state->pkt_next += 2;
   ret = gdb_expect_integer(state, &pid);
   if (ret < 0)
     {
@@ -1756,7 +1797,7 @@ int gdb_process(FAR struct gdb_state_s *state, int stopreason,
       switch (state->pkt_buf[0])
         {
           case '?': /* gdbserial status */
-            ret = gdb_send_stop(state, stopreason, stopaddr);
+            ret = gdb_send_signal_packet(state, 0x00);
             break;
           case 'g': /* Read registers */
             ret = gdb_read_registers(state);