Re: [PATCH v3 3/9] gdbstub: Add support for target-specific stubs

[Gustavo Romero]

Hi Alex,

On 6/21/24 5:11 AM, Alex Bennée wrote:
Gustavo Romero <gustavo.rom...@linaro.org> writes:
Currently, it's not possible to have stubs specific to a given target,
even though there are GDB features which are target-specific, like, for
instance, memory tagging.

This commit introduces gdb_extend_qsupported_features,
gdb_extend_query_table, and gdb_extend_set_table functions as interfaces
to extend the qSupported string, the query handler table, and the set
handler table, allowing target-specific stub implementations.

Signed-off-by: Gustavo Romero <gustavo.rom...@linaro.org>
---
  gdbstub/gdbstub.c          | 59 ++++++++++++++++++++++++++++++++++----
  include/gdbstub/commands.h | 22 ++++++++++++++
  2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 9ff2f4177d..e69cc5131e 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -1609,6 +1609,12 @@ static void handle_query_thread_extra(GArray *params, 
void *user_ctx)
      gdb_put_strbuf();
  }
  
+static char *extended_qsupported_features;
+void gdb_extend_qsupported_features(char *qsupported_features)
+{

   /*
    * We don't support different sets of CPU gdb features on different
    * CPUs yet so assert things are the same.
    */

    g_assert(!extended_qsupported_features ||
    g_strcmp0(extended_qsupported_features, qsupported_features) == 0)

Done in v4. Thanks.


Cheers,
Gustavo

 
+    extended_qsupported_features = qsupported_features;
+}
+
  static void handle_query_supported(GArray *params, void *user_ctx)
  {
      CPUClass *cc;
@@ -1648,6 +1654,11 @@ static void handle_query_supported(GArray *params, void 
*user_ctx)
      }
  
      g_string_append(gdbserver_state.str_buf, ";vContSupported+;multiprocess+");
+
+    if (extended_qsupported_features) {
+        g_string_append(gdbserver_state.str_buf, extended_qsupported_features);
+    }
+
      gdb_put_strbuf();
  }
  
@@ -1729,6 +1740,14 @@ static const GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
      },
  };
  
+static GdbCmdParseEntry *extended_query_table;
+static int extended_query_table_size;
+void gdb_extend_query_table(GdbCmdParseEntry *table, int size)
+{
+    extended_query_table = table;
+    extended_query_table_size = size;

Similar assert here.

+}
+
  static const GdbCmdParseEntry gdb_gen_query_table[] = {
      {
          .handler = handle_query_curr_tid,
@@ -1821,6 +1840,14 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = {
  #endif
  };
  
+static GdbCmdParseEntry *extended_set_table;
+static int extended_set_table_size;
+void gdb_extend_set_table(GdbCmdParseEntry *table, int size)
+{

ditto

+    extended_set_table = table;
+    extended_set_table_size = size;
+}
+
  static const GdbCmdParseEntry gdb_gen_set_table[] = {
      /* Order is important if has same prefix */
      {
@@ -1859,11 +1886,21 @@ static void handle_gen_query(GArray *params, void 
*user_ctx)
          return;
      }
  
-    if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
-                            gdb_gen_query_table,
-                            ARRAY_SIZE(gdb_gen_query_table))) {
-        gdb_put_packet("");
+    if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
+                           gdb_gen_query_table,
+                           ARRAY_SIZE(gdb_gen_query_table))) {
+        return;
+    }
+
+    if (extended_query_table &&
+        process_string_cmd(gdb_get_cmd_param(params, 0)->data,
+                           extended_query_table,
+                           extended_query_table_size)) {
+        return;
      }
+
+    /* Can't handle query, return Empty response. */
+    gdb_put_packet("");
  }
  
  static void handle_gen_set(GArray *params, void *user_ctx)
@@ -1878,11 +1915,21 @@ static void handle_gen_set(GArray *params, void 
*user_ctx)
          return;
      }
  
-    if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
+    if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
                             gdb_gen_set_table,
                             ARRAY_SIZE(gdb_gen_set_table))) {
-        gdb_put_packet("");
+        return;
      }
+
+    if (extended_set_table &&
+        process_string_cmd(gdb_get_cmd_param(params, 0)->data,
+                           extended_set_table,
+                           extended_set_table_size)) {
+        return;
+    }
+
+    /* Can't handle set, return Empty response. */
+    gdb_put_packet("");
  }
  
  static void handle_target_halt(GArray *params, void *user_ctx)
diff --git a/include/gdbstub/commands.h b/include/gdbstub/commands.h
index dd45c38472..2204c3ddbe 100644
--- a/include/gdbstub/commands.h
+++ b/include/gdbstub/commands.h
@@ -71,4 +71,26 @@ typedef struct GdbCmdParseEntry {
   */
  int gdb_put_packet(const char *buf);
  
+/**
+ * gdb_extend_query_table() - Extend query table.
+ * @table: The table with the additional query packet handlers.
+ * @size: The number of handlers to be added.
+ */
+void gdb_extend_query_table(GdbCmdParseEntry *table, int size);
+
+/**
+ * gdb_extend_set_table() - Extend set table.
+ * @table: The table with the additional set packet handlers.
+ * @size: The number of handlers to be added.
+ */
+void gdb_extend_set_table(GdbCmdParseEntry *table, int size);
+
+/**
+ * gdb_extend_qsupported_features() - Extend the qSupported features string.
+ * @qsupported_features: The additional qSupported feature(s) string. The 
string
+ * should start with a semicolon and, if there are more than one feature, the
+ * features should be separate by a semiocolon.
+ */
+void gdb_extend_qsupported_features(char *qsupported_features);
+
  #endif /* GDBSTUB_COMMANDS_H */

Otherwise:

Reviewed-by: Alex Bennée <alex.ben...@linaro.org>