Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/kvm/e500.c b/arch/powerpc/kvm/e500.c
index afd3c25..00649ca 100644
--- a/arch/powerpc/kvm/e500.c
+++ b/arch/powerpc/kvm/e500.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2008-2011 Freescale Semiconductor, Inc. All rights reserved.
  *
@@ -6,10 +7,6 @@
  * Description:
  * This file is derived from arch/powerpc/kvm/44x.c,
  * by Hollis Blanchard <hollisb@us.ibm.com>.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2, as
- * published by the Free Software Foundation.
  */
 
 #include <linux/kvm_host.h>
@@ -443,6 +440,9 @@
 	struct kvm_vcpu *vcpu;
 	int err;
 
+	BUILD_BUG_ON_MSG(offsetof(struct kvmppc_vcpu_e500, vcpu) != 0,
+		"struct kvm_vcpu must be at offset 0 for arch usercopy region");
+
 	vcpu_e500 = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
 	if (!vcpu_e500) {
 		err = -ENOMEM;