efi_loader: allow return value in EFI_CALL

Macro EFI_CALL was introduced to call an UEFI function.
Unfortunately it does not support return values.
Most UEFI functions have a return value.

So let's rename EFI_CALL to EFI_CALL_VOID and introduce a
new EFI_CALL macro that supports return values.

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

include/efi_loader.h

@@ -42,9 +42,22 @@ const char *__efi_nesting_dec(void);
 	})
 
 /*
- * Callback into UEFI world from u-boot:
+ * Call non-void UEFI function from u-boot and retrieve return value:
  */
-#define EFI_CALL(exp) do { \
+#define EFI_CALL(exp) ({ \
+	debug("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
+	assert(__efi_exit_check()); \
+	typeof(exp) _r = exp; \
+	assert(__efi_entry_check()); \
+	debug("%sEFI: %lu returned by %s\n", __efi_nesting_dec(), \
+	      (unsigned long)((uintptr_t)_r & ~EFI_ERROR_MASK), #exp); \
+	_r; \
+})
+
+/*
+ * Call void UEFI function from u-boot:
+ */
+#define EFI_CALL_VOID(exp) do { \
 	debug("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
 	assert(__efi_exit_check()); \
 	exp; \

lib/efi_loader/efi_boottime.c

@@ -163,7 +163,8 @@ void efi_signal_event(struct efi_event *event)
 		return;
 	event->signaled = 1;
 	if (event->type & EVT_NOTIFY_SIGNAL) {
-		EFI_CALL(event->notify_function(event, event->notify_context));
+		EFI_CALL_VOID(event->notify_function(event,
+						     event->notify_context));
 	}
 }