From ed7072c40aa37f180c86c20062d0cc6c8dd2d2e7 Mon Sep 17 00:00:00 2001
From: Patrick Wildt <patrick@cvs.openbsd.org>
Date: Sat, 22 Oct 2016 17:48:42 +0000
Subject: If an Access Flag fault happens while we were running the kernel and
 it happened on a kernel page, we need to consult the kernel pmap instead of
 the current proc's pmap.  Fixes panic when using tmpfs.

ok kettenis@
---
 sys/arch/arm/arm/fault.c     | 5 +----
 sys/arch/arm/arm/pmap7.c     | 5 ++++-
 sys/arch/arm/include/frame.h | 5 ++++-
 3 files changed, 9 insertions(+), 6 deletions(-)

(limited to 'sys/arch/arm')

diff --git a/sys/arch/arm/arm/fault.c b/sys/arch/arm/arm/fault.c
index a9322acf938..788469b6ffa 100644
--- a/sys/arch/arm/arm/fault.c
+++ b/sys/arch/arm/arm/fault.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fault.c,v 1.24 2016/10/08 05:49:08 guenther Exp $	*/
+/*	$OpenBSD: fault.c,v 1.25 2016/10/22 17:48:41 patrick Exp $	*/
 /*	$NetBSD: fault.c,v 1.46 2004/01/21 15:39:21 skrll Exp $	*/
 
 /*
@@ -188,9 +188,6 @@ static const struct data_abort data_aborts[] = {
 #endif
 };
 
-/* Determine if a fault came from user mode */
-#define	TRAP_USERMODE(tf)	((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
-
 /* Determine if 'ftyp' is a permission fault */
 #define	IS_PERMISSION_FAULT(ftyp)				\
 	(((1 << (ftyp)) &					\
diff --git a/sys/arch/arm/arm/pmap7.c b/sys/arch/arm/arm/pmap7.c
index b7e0b6fa7f2..f99ee582e00 100644
--- a/sys/arch/arm/arm/pmap7.c
+++ b/sys/arch/arm/arm/pmap7.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap7.c,v 1.54 2016/10/19 08:28:19 guenther Exp $	*/
+/*	$OpenBSD: pmap7.c,v 1.55 2016/10/22 17:48:41 patrick Exp $	*/
 /*	$NetBSD: pmap.c,v 1.147 2004/01/18 13:03:50 scw Exp $	*/
 
 /*
@@ -1697,6 +1697,9 @@ dab_access(trapframe_t *tf, u_int fsr, u_int far, struct proc *p)
 	paddr_t pa;
 	u_int l1idx;
 
+	if (!TRAP_USERMODE(tf) && far >= VM_MIN_KERNEL_ADDRESS)
+		pm = pmap_kernel();
+
 	l1idx = L1_IDX(va);
 
 	/*
diff --git a/sys/arch/arm/include/frame.h b/sys/arch/arm/include/frame.h
index 8aaaec07712..dd68dcc5d99 100644
--- a/sys/arch/arm/include/frame.h
+++ b/sys/arch/arm/include/frame.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: frame.h,v 1.10 2016/04/25 08:00:43 patrick Exp $	*/
+/*	$OpenBSD: frame.h,v 1.11 2016/10/22 17:48:41 patrick Exp $	*/
 /*	$NetBSD: frame.h,v 1.9 2003/12/01 08:48:33 scw Exp $	*/
 
 /*
@@ -83,6 +83,9 @@ typedef struct trapframe {
 #define tf_r14 tf_usr_lr
 #define tf_r15 tf_pc
 
+/* Determine if a fault came from user mode */
+#define	TRAP_USERMODE(tf)	((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
+
 /*
  * Signal frame.  Pushed onto user stack before calling sigcode.
  */
-- 
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