From 69b3f4f99de389a87f62062cede1d217f2ead481 Mon Sep 17 00:00:00 2001
From: andrew <andrew@FreeBSD.org>
Date: Mon, 22 Aug 2016 18:19:46 +0000
Subject: [PATCH] Ensure map is valid, even before userland exists and the
 fault address register points to an address in the userland range.

Obtained from:	ABT Systems Ltd
MFC after:	1 week
Sponsored by:	the FreeBSD Foundation
---
 sys/arm64/arm64/trap.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
index d9367dfcf742..a126d04582d6 100644
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -184,10 +184,13 @@ data_abort(struct trapframe *frame, uint64_t esr, uint64_t far, int lower)
 		map = &p->p_vmspace->vm_map;
 	else {
 		/* The top bit tells us which range to use */
-		if ((far >> 63) == 1)
+		if ((far >> 63) == 1) {
 			map = kernel_map;
-		else
+		} else {
 			map = &p->p_vmspace->vm_map;
+			if (map == NULL)
+				map = kernel_map;
+		}
 	}
 
 	if (pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)