+/**
+ * efi_start_image() - call the entry point of an image
+ * @image_handle: handle of the image
+ * @exit_data_size: size of the buffer
+ * @exit_data: buffer to receive the exit data of the called image
+ *
+ * This function implements the StartImage service.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification for
+ * details.
+ *
+ * Return: status code
+ */
+efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
+ efi_uintn_t *exit_data_size,
+ u16 **exit_data)
+{
+ struct efi_loaded_image_obj *image_obj =
+ (struct efi_loaded_image_obj *)image_handle;
+ efi_status_t ret;
+ void *info;
+ efi_handle_t parent_image = current_image;
+
+ EFI_ENTRY("%p, %p, %p", image_handle, exit_data_size, exit_data);
+
+ /* Check parameters */
+ ret = EFI_CALL(efi_open_protocol(image_handle, &efi_guid_loaded_image,
+ &info, NULL, NULL,
+ EFI_OPEN_PROTOCOL_GET_PROTOCOL));
+ if (ret != EFI_SUCCESS)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ efi_is_direct_boot = false;
+
+ image_obj->exit_data_size = exit_data_size;
+ image_obj->exit_data = exit_data;
+
+ /* call the image! */
+ if (setjmp(&image_obj->exit_jmp)) {
+ /*
+ * We called the entry point of the child image with EFI_CALL
+ * in the lines below. The child image called the Exit() boot
+ * service efi_exit() which executed the long jump that brought
+ * us to the current line. This implies that the second half
+ * of the EFI_CALL macro has not been executed.
+ */
+#ifdef CONFIG_ARM
+ /*
+ * efi_exit() called efi_restore_gd(). We have to undo this
+ * otherwise __efi_entry_check() will put the wrong value into
+ * app_gd.
+ */
+ gd = app_gd;
+#endif
+ /*
+ * To get ready to call EFI_EXIT below we have to execute the
+ * missed out steps of EFI_CALL.
+ */
+ assert(__efi_entry_check());
+ debug("%sEFI: %lu returned by started image\n",
+ __efi_nesting_dec(),
+ (unsigned long)((uintptr_t)image_obj->exit_status &
+ ~EFI_ERROR_MASK));
+ current_image = parent_image;
+ return EFI_EXIT(image_obj->exit_status);
+ }
+
+ current_image = image_handle;
+ EFI_PRINT("Jumping into 0x%p\n", image_obj->entry);
+ ret = EFI_CALL(image_obj->entry(image_handle, &systab));
+
+ /*
+ * Usually UEFI applications call Exit() instead of returning.
+ * But because the world doesn't consist of ponies and unicorns,
+ * we're happy to emulate that behavior on behalf of a payload
+ * that forgot.
+ */
+ return EFI_CALL(systab.boottime->exit(image_handle, ret, 0, NULL));
+}
+
+/**
+ * efi_update_exit_data() - fill exit data parameters of StartImage()
+ *
+ * @image_obj image handle
+ * @exit_data_size size of the exit data buffer
+ * @exit_data buffer with data returned by UEFI payload
+ * Return: status code
+ */
+static efi_status_t efi_update_exit_data(struct efi_loaded_image_obj *image_obj,
+ efi_uintn_t exit_data_size,
+ u16 *exit_data)
+{
+ efi_status_t ret;
+
+ /*
+ * If exit_data is not provided to StartImage(), exit_data_size must be
+ * ignored.
+ */
+ if (!image_obj->exit_data)
+ return EFI_SUCCESS;
+ if (image_obj->exit_data_size)
+ *image_obj->exit_data_size = exit_data_size;
+ if (exit_data_size && exit_data) {
+ ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA,
+ exit_data_size,
+ (void **)image_obj->exit_data);
+ if (ret != EFI_SUCCESS)
+ return ret;
+ memcpy(*image_obj->exit_data, exit_data, exit_data_size);
+ } else {
+ image_obj->exit_data = NULL;
+ }
+ return EFI_SUCCESS;
+}
+
+/**
+ * efi_exit() - leave an EFI application or driver
+ * @image_handle: handle of the application or driver that is exiting
+ * @exit_status: status code
+ * @exit_data_size: size of the buffer in bytes
+ * @exit_data: buffer with data describing an error
+ *
+ * This function implements the Exit service.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification for
+ * details.
+ *
+ * Return: status code
+ */
+static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
+ efi_status_t exit_status,
+ efi_uintn_t exit_data_size,
+ u16 *exit_data)
+{
+ /*
+ * TODO: We should call the unload procedure of the loaded
+ * image protocol.
+ */
+ efi_status_t ret;
+ void *info;
+ struct efi_loaded_image_obj *image_obj =
+ (struct efi_loaded_image_obj *)image_handle;
+
+ EFI_ENTRY("%p, %ld, %zu, %p", image_handle, exit_status,
+ exit_data_size, exit_data);
+
+ /* Check parameters */
+ if (image_handle != current_image)
+ goto out;
+ ret = EFI_CALL(efi_open_protocol(image_handle, &efi_guid_loaded_image,
+ &info, NULL, NULL,
+ EFI_OPEN_PROTOCOL_GET_PROTOCOL));
+ if (ret != EFI_SUCCESS)
+ goto out;
+
+ /* Exit data is only foreseen in case of failure. */
+ if (exit_status != EFI_SUCCESS) {
+ ret = efi_update_exit_data(image_obj, exit_data_size,
+ exit_data);
+ /* Exiting has priority. Don't return error to caller. */
+ if (ret != EFI_SUCCESS)
+ EFI_PRINT("%s: out of memory\n", __func__);
+ }
+
+ /* Make sure entry/exit counts for EFI world cross-overs match */
+ EFI_EXIT(exit_status);
+
+ /*
+ * But longjmp out with the U-Boot gd, not the application's, as
+ * the other end is a setjmp call inside EFI context.
+ */
+ efi_restore_gd();
+
+ image_obj->exit_status = exit_status;
+ longjmp(&image_obj->exit_jmp, 1);
+
+ panic("EFI application exited");
+out:
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+}
+