diff --git a/arch/x86/include/asm/smm.h b/arch/x86/include/asm/smm.h
new file mode 100644
index 0000000..1e539fd
--- /dev/null
+++ b/arch/x86/include/asm/smm.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SMM definitions (U-Boot does not support SMM itself)
+ *
+ * Copyright (C) 2008-2009 coresystems GmbH
+ * Copyright 2019 Google LLC
+ *
+ * Modified from coreboot smm.h
+ */
+
+#ifndef _ASM_SMM_H
+#define _ASM_SMM_H
+
+#define APM_CNT			0xb2
+#define APM_CNT_CST_CONTROL	0x85
+#define APM_CNT_PST_CONTROL	0x80
+#define APM_CNT_ACPI_DISABLE	0x1e
+#define APM_CNT_ACPI_ENABLE	0xe1
+#define APM_CNT_MBI_UPDATE	0xeb
+#define APM_CNT_GNVS_UPDATE	0xea
+#define APM_CNT_FINALIZE	0xcb
+#define APM_CNT_LEGACY		0xcc
+#define APM_CNT_SMMSTORE	0xed
+#define APM_CNT_ELOG_GSMI	0xef
+#define APM_STS			0xb3
+
+#endif /* _ASM_SMM_H */