efi_loader: create stub for CreateEventEx

Currently we set the function pointer for the CreateEventEx boot service
to NULL. When called this would lead to an immediate failure.

A function stub is provided which handles the case that the boot service
is called without an event group and returns EFI_UNSUPPORTED otherwise.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

include/efi_api.h

@@ -166,7 +166,14 @@ struct efi_boot_services {
 	void (EFIAPI *copy_mem)(void *destination, const void *source,
 			size_t length);
 	void (EFIAPI *set_mem)(void *buffer, size_t size, uint8_t value);
-	void *create_event_ex;
+	efi_status_t (EFIAPI *create_event_ex)(
+				uint32_t type, efi_uintn_t notify_tpl,
+				void (EFIAPI *notify_function) (
+					struct efi_event *event,
+					void *context),
+				void *notify_context,
+				efi_guid_t *event_group,
+				struct efi_event **event);
 };
 
 /* Types and defines for EFI ResetSystem */

lib/efi_loader/efi_boottime.c

@@ -525,6 +525,38 @@ efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl,
 	return EFI_OUT_OF_RESOURCES;
 }
 
+/*
+ * Create an event in a group.
+ *
+ * This function implements the CreateEventEx service.
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ * TODO: Support event groups
+ *
+ * @type		type of the event to create
+ * @notify_tpl		task priority level of the event
+ * @notify_function	notification function of the event
+ * @notify_context	pointer passed to the notification function
+ * @event		created event
+ * @event_group		event group
+ * @return		status code
+ */
+efi_status_t EFIAPI efi_create_event_ex(uint32_t type, efi_uintn_t notify_tpl,
+					void (EFIAPI *notify_function) (
+							struct efi_event *event,
+							void *context),
+					void *notify_context,
+					efi_guid_t *event_group,
+					struct efi_event **event)
+{
+	EFI_ENTRY("%d, 0x%zx, %p, %p, %pUl", type, notify_tpl, notify_function,
+		  notify_context, event_group);
+	if (event_group)
+		return EFI_EXIT(EFI_UNSUPPORTED);
+	return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
+					 notify_context, event));
+}
+
 /*
  * Create an event.
  *
@@ -2851,6 +2883,7 @@ static const struct efi_boot_services efi_boot_services = {
 	.calculate_crc32 = efi_calculate_crc32,
 	.copy_mem = efi_copy_mem,
 	.set_mem = efi_set_mem,
+	.create_event_ex = efi_create_event_ex,
 };