Index: sys/arm/linux/linux_support.s
===================================================================
--- /dev/null
+++ sys/arm/linux/linux_support.s
@@ -0,0 +1,115 @@
+/*-
+ * Copyright (c) 2016 Gregory Soutade
+ * Copyright (c) 2006,2007 Konstantin Belousov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include "linux_assym.h"		/* system definitions */
+#include <machine/asmacros.h>		/* miscellaneous asm macros */
+#define EFAULT 1
+
+#include "assym.s"
+
+.vm_maxuser_address: .word VM_MAXUSER_ADDRESS-4
+
+#if __ARM_ARCH >= 6
+#define GET_PCB(tmp) \
+	mrc	p15, 0, tmp, c13, c0, 4 ; \
+	add	tmp, tmp, #(TD_PCB)
+#else
+	.Lcurpcb:
+	.word	 _C_LABEL(__pcpu) + PC_CURPCB
+#define GET_PCB(tmp) \
+	ldr	tmp, .Lcurpcb
+#endif
+
+
+futex_fault:
+	GET_PCB(r3)
+	ldr	r3, [r3]
+	mov	r4, #0
+	str	r4, [r3, #PCB_ONFAULT]
+	pop	{r3, r4, r5, r6}
+	mov	r0, #-EFAULT
+	mov	pc, lr
+/*
+	r0 : int oparg
+	r1 : uint32_t *uaddr
+	r2 : int *oldval
+*/
+#define FUTEX_HEAD(err_fun)\
+	push	{r3, r4, r5, r6};\
+	adr	r4, .vm_maxuser_address ;\
+	ldr	r4, [r4]		;\
+	cmp	r1, r4 ;\
+	popgt	{r3, r4, r5, r6};\
+	movgt	r0, #-EFAULT;\
+	movgt	pc, lr;\
+	GET_PCB(r3) ;\
+	ldr	r3, [r3] ;\
+	adr	r5, err_fun ;\
+	str	r5, [r3, #PCB_ONFAULT];\
+1:;\
+	ldrex	r4, [r1]
+
+#define FUTEX_TAIL()\
+	strex	r5, r6, [r1];\
+	cmp	r5, #0;\
+	bne	1b;\
+	str	r4, [r2] ;\
+	mov	r5, #0 ;\
+	str	r5, [r3, #PCB_ONFAULT] ;\
+	pop	{r3, r4, r5, r6};\
+	mov	r0, #0;\
+	mov	pc, lr
+
+ENTRY(futex_xchgl)
+	FUTEX_HEAD(futex_fault)
+	mov	r6, r0
+	FUTEX_TAIL()
+
+ENTRY(futex_addl)
+	FUTEX_HEAD(futex_fault)
+	add	r6, r0, r4
+	FUTEX_TAIL()
+
+ENTRY(futex_orl)
+	FUTEX_HEAD(futex_fault)
+	orr	r6, r0, r4
+	FUTEX_TAIL()
+
+ENTRY(futex_andl)
+	FUTEX_HEAD(futex_fault)
+	and	r6, r0, r4
+	FUTEX_TAIL()
+
+ENTRY(futex_xorl)
+	FUTEX_HEAD(futex_fault)
+	eor	r6, r0, r4
+	FUTEX_TAIL()