efi_loader: helper function to add EFI object to list

To avoid duplicate coding provide a helper function that
initializes an EFI object and adds it to the EFI object
list.

efi_exit() is the only place where we dereference a handle
to obtain a protocol interface. Add a comment to the function.

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

include/efi_loader.h

@@ -186,6 +186,8 @@ void efi_restore_gd(void);
 void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map);
 /* Call this to set the current device name */
 void efi_set_bootdev(const char *dev, const char *devnr, const char *path);
+/* Add a new object to the object list. */
+void efi_add_handle(struct efi_object *obj);
 /* Create handle */
 efi_status_t efi_create_handle(void **handle);
 /* Call this to validate a handle and find the EFI object for it */

lib/efi_loader/efi_boottime.c

@@ -321,6 +321,23 @@ static efi_status_t EFIAPI efi_free_pool_ext(void *buffer)
 	return EFI_EXIT(r);
 }
 
+/*
+ * Add a new object to the object list.
+ *
+ * The protocols list is initialized.
+ * The object handle is set.
+ *
+ * @obj	object to be added
+ */
+void efi_add_handle(struct efi_object *obj)
+{
+	if (!obj)
+		return;
+	INIT_LIST_HEAD(&obj->protocols);
+	obj->handle = obj;
+	list_add_tail(&obj->link, &efi_obj_list);
+}
+
 /*
  * Create handle.
  *
@@ -337,11 +354,8 @@ efi_status_t efi_create_handle(void **handle)
 			      (void **)&obj);
 	if (r != EFI_SUCCESS)
 		return r;
-	memset(obj, 0, sizeof(struct efi_object));
+	efi_add_handle(obj);
-	obj->handle = obj;
+	*handle = obj->handle;
-	INIT_LIST_HEAD(&obj->protocols);
-	list_add_tail(&obj->link, &efi_obj_list);
-	*handle = obj;
 	return r;
 }
 
@@ -1163,14 +1177,15 @@ void efi_setup_loaded_image(struct efi_loaded_image *info, struct efi_object *ob
 {
 	efi_status_t ret;
 
+	/* Add internal object to object list */
+	efi_add_handle(obj);
+	/* efi_exit() assumes that the handle points to the info */
 	obj->handle = info;
 
 	info->file_path = file_path;
 	if (device_path)
 		info->device_handle = efi_dp_find_obj(device_path, NULL);
 
-	INIT_LIST_HEAD(&obj->protocols);
-	list_add_tail(&obj->link, &efi_obj_list);
 	/*
 	 * When asking for the device path interface, return
 	 * bootefi_device_path
@@ -1379,6 +1394,17 @@ 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,

lib/efi_loader/efi_disk.c

@@ -224,13 +224,11 @@ static void efi_disk_add_dev(const char *name,
 		goto out_of_memory;
 
 	/* Hook up to the device list */
-	INIT_LIST_HEAD(&diskobj->parent.protocols);
+	efi_add_handle(&diskobj->parent);
-	list_add_tail(&diskobj->parent.link, &efi_obj_list);
 
 	/* Fill in object data */
 	diskobj->dp = efi_dp_from_part(desc, part);
 	diskobj->part = part;
-	diskobj->parent.handle = diskobj;
 	ret = efi_add_protocol(diskobj->parent.handle, &efi_block_io_guid,
 			       &diskobj->ops);
 	if (ret != EFI_SUCCESS)

lib/efi_loader/efi_gop.c

@@ -180,11 +180,9 @@ int efi_gop_register(void)
 	}
 
 	/* Hook up to the device list */
-	INIT_LIST_HEAD(&gopobj->parent.protocols);
+	efi_add_handle(&gopobj->parent);
-	list_add_tail(&gopobj->parent.link, &efi_obj_list);
 
 	/* Fill in object data */
-	gopobj->parent.handle = &gopobj->ops;
 	ret = efi_add_protocol(gopobj->parent.handle, &efi_gop_guid,
 			       &gopobj->ops);
 	if (ret != EFI_SUCCESS) {

lib/efi_loader/efi_net.c

@@ -296,11 +296,9 @@ int efi_net_register(void)
 		goto out_of_memory;
 
 	/* Hook net up to the device list */
-	INIT_LIST_HEAD(&netobj->parent.protocols);
+	efi_add_handle(&netobj->parent);
-	list_add_tail(&netobj->parent.link, &efi_obj_list);
 
 	/* Fill in object data */
-	netobj->parent.handle = &netobj->net;
 	r = efi_add_protocol(netobj->parent.handle, &efi_net_guid,
 			     &netobj->net);
 	if (r != EFI_SUCCESS)