efi_loader: output load options in helloworld

We need to test if we pass a valid image handle when loading
and EFI application. This cannot be done in efi_selftest as
it is not loaded as an image.

So let's enhance helloworld a bit.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

lib/efi_loader/helloworld.c

@@ -5,19 +5,52 @@
  * Written by Simon Glass <sjg@chromium.org>
  *
  * SPDX-License-Identifier:     GPL-2.0+
+ *
+ * This program demonstrates calling a boottime service.
+ * It writes a greeting and the load options to the console.
  */
 
 #include <common.h>
 #include <efi_api.h>
 
+/*
+ * Entry point of the EFI application.
+ *
+ * @handle	handle of the loaded image
+ * @systable	system table
+ * @return	status code
+ */
 efi_status_t EFIAPI efi_main(efi_handle_t handle,
 			     struct efi_system_table *systable)
 {
 	struct efi_simple_text_output_protocol *con_out = systable->con_out;
 	struct efi_boot_services *boottime = systable->boottime;
+	struct efi_loaded_image *loaded_image;
+	const efi_guid_t loaded_image_guid = LOADED_IMAGE_GUID;
+	efi_status_t ret;
 
 	con_out->output_string(con_out, L"Hello, world!\n");
-	boottime->exit(handle, 0, 0, NULL);
 
-	return EFI_SUCCESS;
+	/* Get the loaded image protocol */
+	ret = boottime->handle_protocol(handle, &loaded_image_guid,
+					(void **)&loaded_image);
+	if (ret != EFI_SUCCESS) {
+		con_out->output_string(con_out,
+				       L"Cannot open loaded image protocol\n");
+		goto out;
+	}
+	/* Output the load options */
+	con_out->output_string(con_out, L"Load options: ");
+	if (loaded_image->load_options_size && loaded_image->load_options)
+		con_out->output_string(con_out,
+				       (u16 *)loaded_image->load_options);
+	else
+		con_out->output_string(con_out, L"<none>");
+	con_out->output_string(con_out, L"\n");
+
+out:
+	boottime->exit(handle, ret, 0, NULL);
+
+	/* We should never arrive here */
+	return ret;
 }