v4.19.13 snapshot.
diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c
new file mode 100644
index 0000000..9f34049
--- /dev/null
+++ b/arch/powerpc/lib/vmx-helper.c
@@ -0,0 +1,78 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2011
+ *
+ * Authors: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
+ * Anton Blanchard <anton@au.ibm.com>
+ */
+#include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <asm/switch_to.h>
+#include <asm/asm-prototypes.h>
+
+int enter_vmx_usercopy(void)
+{
+ if (in_interrupt())
+ return 0;
+
+ preempt_disable();
+ /*
+ * We need to disable page faults as they can call schedule and
+ * thus make us lose the VMX context. So on page faults, we just
+ * fail which will cause a fallback to the normal non-vmx copy.
+ */
+ pagefault_disable();
+
+ enable_kernel_altivec();
+
+ return 1;
+}
+
+/*
+ * This function must return 0 because we tail call optimise when calling
+ * from __copy_tofrom_user_power7 which returns 0 on success.
+ */
+int exit_vmx_usercopy(void)
+{
+ disable_kernel_altivec();
+ pagefault_enable();
+ preempt_enable();
+ return 0;
+}
+
+int enter_vmx_ops(void)
+{
+ if (in_interrupt())
+ return 0;
+
+ preempt_disable();
+
+ enable_kernel_altivec();
+
+ return 1;
+}
+
+/*
+ * All calls to this function will be optimised into tail calls. We are
+ * passed a pointer to the destination which we return as required by a
+ * memcpy implementation.
+ */
+void *exit_vmx_ops(void *dest)
+{
+ disable_kernel_altivec();
+ preempt_enable();
+ return dest;
+}