diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
index 18cafe3ebddc..3b6f45a2edc8 100644
--- a/include/acpi/actbl2.h
+++ b/include/acpi/actbl2.h
@@ -763,6 +763,20 @@ struct acpi_madt_multiproc_wakeup {
 	u64 base_address;
 };
 
+#define ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE	2032
+#define ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE	2048
+
+struct acpi_madt_multiproc_wakeup_mailbox {
+	u16 command;
+	u16 reserved;		/* reserved - must be zero */
+	u32 apic_id;
+	u64 wakeup_vector;
+	u8 reserved_os[ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE];	/* reserved for OS use */
+	u8 reserved_firmware[ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE];	/* reserved for firmware use */
+};
+
+#define ACPI_MP_WAKE_COMMAND_WAKEUP    1
+
 /*
  * Common flags fields for MADT subtables
  */