Index: head/sys/arm64/include/asm.h
===================================================================
--- head/sys/arm64/include/asm.h	(revision 316625)
+++ head/sys/arm64/include/asm.h	(revision 316626)
@@ -1,71 +1,74 @@
 /*-
  * Copyright (c) 2014 Andrew Turner
  * 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.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
  *
  * $FreeBSD$
  */
 
 #ifndef _MACHINE_ASM_H_
 #define	_MACHINE_ASM_H_
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
 #define	__FBSDID(s)     .ident s
 #else
 #define	__FBSDID(s)     /* nothing */
 #endif
 
 #define	_C_LABEL(x)	x
 
 #define	ENTRY(sym)						\
 	.text; .globl sym; .align 2; .type sym,#function; sym:
 #define	EENTRY(sym)						\
 	.globl	sym; sym:
 #define	END(sym) .size sym, . - sym
 #define	EEND(sym)
 
 #define	WEAK_REFERENCE(sym, alias)				\
 	.weak alias;						\
 	.set alias,sym
 
 #define	UINT64_C(x)	(x)
 
 #if defined(PIC)
 #define	PIC_SYM(x,y)	x ## @ ## y
 #else
 #define	PIC_SYM(x,y)	x
 #endif
 
+/* Alias for link register x30 */
+#define	lr		x30
+
 /*
  * Sets the trap fault handler. The exception handler will return to the
  * address in the handler register on a data abort or the xzr register to
  * clear the handler. The tmp parameter should be a register able to hold
  * the temporary data.
  */
 #define	SET_FAULT_HANDLER(handler, tmp)					\
 	ldr	tmp, [x18, #PC_CURTHREAD];	/* Load curthread */	\
 	ldr	tmp, [tmp, #TD_PCB];		/* Load the pcb */	\
 	str	handler, [tmp, #PCB_ONFAULT]	/* Set the handler */
 
 #endif /* _MACHINE_ASM_H_ */