gdbstub: Pass CPU context to command handler

Allow passing the current CPU context to command handlers via user_ctx
when the handler requires it.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Message-Id: <20240628050850.536447-9-gustavo.romero@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240705084047.857176-38-alex.bennee@linaro.org>

gdbstub/gdbstub.c

@@ -938,6 +938,7 @@ static bool process_string_cmd(const char *data,
 
     for (i = 0; i < num_cmds; i++) {
         const GdbCmdParseEntry *cmd = &cmds[i];
+        void *user_ctx = NULL;
         g_assert(cmd->handler && cmd->cmd);
 
         if ((cmd->cmd_startswith && !startswith(data, cmd->cmd)) ||
@@ -952,8 +953,12 @@ static bool process_string_cmd(const char *data,
             }
         }
 
+        if (cmd->need_cpu_context) {
+            user_ctx = (void *)gdbserver_state.g_cpu;
+        }
+
         gdbserver_state.allow_stop_reply = cmd->allow_stop_reply;
-        cmd->handler(params, NULL);
+        cmd->handler(params, user_ctx);
         return true;
     }
 

include/gdbstub/commands.h

@@ -54,6 +54,8 @@ typedef union GdbCmdVariant {
  * "stop reply" packet. The list of commands that accept such response is
  * defined at the GDB Remote Serial Protocol documentation. See:
  * https://sourceware.org/gdb/onlinedocs/gdb/Stop-Reply-Packets.html#Stop-Reply-Packets.
+ *
+ * @need_cpu_context: Pass current CPU context to command handler via user_ctx.
  */
 typedef struct GdbCmdParseEntry {
     GdbCmdHandler handler;
@@ -61,6 +63,7 @@ typedef struct GdbCmdParseEntry {
     bool cmd_startswith;
     const char *schema;
     bool allow_stop_reply;
+    bool need_cpu_context;
 } GdbCmdParseEntry;
 
 /**