[U-Boot] [PATCH 1/1] efi_loader: always call Exit after an image returns.

[Heinrich Schuchardt]

If an application or driver started via StartImage returns without
calling Exit, StartImage has to call Exit. This is mandated by the
UEFI spec and we do the same in efi_do_enter().

The patch looks bigger than it is. To avoid a forward declaration function
efi_exit() was moved up. Only one (void*) was replaced by (void *).
The only real change is in efi_start_image().

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
Without this patch on Ubuntu 16.04 a crash could be observed in
efi_selftest_startimage_return.c. With the patch it is gone.
But this could be coincidence.
---
 lib/efi_loader/efi_boottime.c | 99 ++++++++++++++++++++++---------------------
 1 file changed, 51 insertions(+), 48 deletions(-)

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 0ac5b44..62a24bf 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1519,6 +1519,54 @@ failure:
 }
 
 /*
+ * Leave an EFI application or driver.
+ *
+ * This function implements the Exit service.
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @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
+ * @return		status code
+ */
+static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
+			efi_status_t exit_status, unsigned long exit_data_size,
+			int16_t *exit_data)
+{
+	/*
+	 * We require that the handle points to the original loaded
+	 * image protocol interface.
+	 *
+	 * For getting the longjmp address this is safer than locating
+	 * the protocol because the protocol may have been reinstalled
+	 * pointing to another memory location.
+	 *
+	 * TODO: We should call the unload procedure of the loaded
+	 *	 image protocol.
+	 */
+	struct efi_loaded_image *loaded_image_info = (void *)image_handle;
+
+	EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
+		  exit_data_size, exit_data);
+
+	/* 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();
+
+	loaded_image_info->exit_status = exit_status;
+	longjmp(&loaded_image_info->exit_jmp, 1);
+
+	panic("EFI application exited");
+}
+
+/*
  * Call the entry point of an image.
  *
  * This function implements the StartImage service.
@@ -1575,59 +1623,14 @@ static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
 
 	ret = EFI_CALL(entry(image_handle, &systab));
 
+	/* Clean up the image */
+	ret = EFI_CALL(efi_exit(image_handle, ret, 0, NULL));
+
 	/* Should usually never get here */
 	return EFI_EXIT(ret);
 }
 
 /*
- * Leave an EFI application or driver.
- *
- * This function implements the Exit service.
- * See the Unified Extensible Firmware Interface (UEFI) specification
- * for details.
- *
- * @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
- * @return		status code
- */
-static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
-			efi_status_t exit_status, unsigned long exit_data_size,
-			int16_t *exit_data)
-{
-	/*
-	 * We require that the handle points to the original loaded
-	 * image protocol interface.
-	 *
-	 * For getting the longjmp address this is safer than locating
-	 * the protocol because the protocol may have been reinstalled
-	 * pointing to another memory location.
-	 *
-	 * TODO: We should call the unload procedure of the loaded
-	 *	 image protocol.
-	 */
-	struct efi_loaded_image *loaded_image_info = (void*)image_handle;
-
-	EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
-		  exit_data_size, exit_data);
-
-	/* 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();
-
-	loaded_image_info->exit_status = exit_status;
-	longjmp(&loaded_image_info->exit_jmp, 1);
-
-	panic("EFI application exited");
-}
-
-/*
  * Unload an EFI image.
  *
  * This function implements the UnloadImage service.
-- 
2.7.4