efi_loader: show UEFI revision in helloworld

Output the UEFI revision number in helloworld.

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

lib/efi_loader/helloworld.c

@@ -46,9 +46,27 @@ efi_status_t EFIAPI efi_main(efi_handle_t handle,
 	struct efi_loaded_image *loaded_image;
 	efi_status_t ret;
 	efi_uintn_t i;
+	u16 rev[] = L"0.0.0";
 
 	con_out->output_string(con_out, L"Hello, world!\n");
 
+	/* Print the revision number */
+	rev[0] = (systable->hdr.revision >> 16) + '0';
+	rev[4] = systable->hdr.revision & 0xffff;
+	for (; rev[4] >= 10;) {
+		rev[4] -= 10;
+		++rev[2];
+	}
+	/* Third digit is only to be shown if non-zero */
+	if (rev[4])
+		rev[4] += '0';
+	else
+		rev[3] = 0;
+
+	con_out->output_string(con_out, L"Running on UEFI ");
+	con_out->output_string(con_out, rev);
+	con_out->output_string(con_out, L"\n");
+
 	/* Get the loaded image protocol */
 	ret = boottime->handle_protocol(handle, &loaded_image_guid,
 					(void **)&loaded_image);