Add list_config generation

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/programs/test/query_config.h b/programs/test/query_config.h
index 0fad886..290100f 100644
--- a/programs/test/query_config.h
+++ b/programs/test/query_config.h
@@ -35,4 +35,12 @@
  */
 int query_config( const char *config );
 
+/** List all enabled configuration symbols
+ *
+ * \note            This function is defined in `programs/test/query_config.c`
+ *                  which is automatically generated by
+ *                  `scripts/generate_query_config.pl`.
+ */
+void list_config( void );
+
 #endif /* MBEDTLS_PROGRAMS_TEST_QUERY_CONFIG_H */
diff --git a/scripts/data_files/query_config.fmt b/scripts/data_files/query_config.fmt
index ffa816e..e0e14cb 100644
--- a/scripts/data_files/query_config.fmt
+++ b/scripts/data_files/query_config.fmt
@@ -99,6 +99,10 @@
 #define MACRO_NAME_TO_STR(macro)                                        \
     mbedtls_printf( "%s", strlen( #macro "" ) > 0 ? #macro "\n" : "" )
 
+#define NAME_TO_STR(macro)  #macro
+#define OUTPUT_MACRO_NAME_VALUE(macro) mbedtls_printf( #macro "%s\n",   \
+    strlen( NAME_TO_STR(macro) "") > 0 ? "=" NAME_TO_STR(macro) : "" )
+
 #if defined(_MSC_VER)
 /*
  * Visual Studio throws the warning 4003 because many Mbed TLS feature macros
@@ -118,6 +122,10 @@
     return( 1 );
 }
 
+void list_config( void )
+{
+    LIST_CONFIG
+}
 #if defined(_MSC_VER)
 #pragma warning(pop)
 #endif /* _MSC_VER */
diff --git a/scripts/generate_query_config.pl b/scripts/generate_query_config.pl
index 7855c7c..b2ce8fc 100755
--- a/scripts/generate_query_config.pl
+++ b/scripts/generate_query_config.pl
@@ -68,6 +68,7 @@
 # This variable will contain the string to replace in the CHECK_CONFIG of the
 # format file
 my $config_check = "";
+my $list_config = "";
 
 while (my $line = <CONFIG_FILE>) {
     if ($line =~ /^(\/\/)?\s*#\s*define\s+(MBEDTLS_\w+).*/) {
@@ -84,6 +85,11 @@
         $config_check .= "    }\n";
         $config_check .= "#endif /* $name */\n";
         $config_check .= "\n";
+
+        $list_config .= "#if defined($name)\n";
+        $list_config .= "    OUTPUT_MACRO_NAME_VALUE($name);\n";
+        $list_config .= "#endif /* $name */\n";
+        $list_config .= "\n";
     }
 }
 
@@ -95,6 +101,7 @@
 
 # Replace the body of the query_config() function with the code we just wrote
 $query_config_format =~ s/CHECK_CONFIG/$config_check/g;
+$query_config_format =~ s/LIST_CONFIG/$list_config/g;
 
 # Rewrite the query_config.c file
 open(QUERY_CONFIG_FILE, ">$query_config_file") or die "Opening destination file '$query_config_file': $!";