diff --git a/lib/libthr/arch/amd64/include/pthread_md.h b/lib/libthr/arch/amd64/include/pthread_md.h
index f43578a8241a..995f35cb569c 100644
--- a/lib/libthr/arch/amd64/include/pthread_md.h
+++ b/lib/libthr/arch/amd64/include/pthread_md.h
@@ -1,55 +1,55 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause
  *
  * Copyright (C) 2003 David Xu <davidxu@freebsd.org>
  * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
  * 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. Neither the name of the author 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 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.
  */
 
 /*
  * Machine-dependent thread prototypes/definitions.
  */
 #ifndef _PTHREAD_MD_H_
 #define	_PTHREAD_MD_H_
 
 #include <stddef.h>
 #include <sys/types.h>
 #include <machine/tls.h>
 
 #define	CPU_SPINWAIT		__asm __volatile("pause")
 
 /* For use in _Static_assert to check structs will fit in a page */
 #define	THR_PAGE_SIZE_MIN	PAGE_SIZE
 
 static __inline struct pthread *
 _get_curthread(void)
 {
 	struct pthread *thr;
 
-	__asm __volatile("movq %%fs:%1, %0" : "=r" (thr)
-	    : "m" (*(volatile u_long *)offsetof(struct tcb, tcb_thread)));
+	__asm __volatile("movq %%fs:%c1, %0" : "=r" (thr)
+	    : "i" (offsetof(struct tcb, tcb_thread)));
 	return (thr);
 }
 
 #endif