Index: arch/hppa/hppa/sys_machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/hppa/hppa/sys_machdep.c,v
retrieving revision 1.3
diff -u -p -r1.3 sys_machdep.c
--- arch/hppa/hppa/sys_machdep.c	2 Jun 2003 23:27:46 -0000	1.3
+++ arch/hppa/hppa/sys_machdep.c	26 Jun 2015 06:57:55 -0000
@@ -56,3 +56,68 @@ sys_sysarch(p, v, retval)
 	}
 	return (error);
 }
+
+#include <sys/rwlock.h>
+#include <sys/signalvar.h>
+
+struct rwlock sys_cas_lock = RWLOCK_INITIALIZER("cas");
+
+int
+sys_cas_uint(struct proc *p, void *v, register_t *retval)
+{
+	struct sys_cas_uint_args /* {
+		syscallarg(u_int *) p;
+		syscallarg(u_int) e;
+		syscallarg(u_int) n;
+	} */ *uap = v;
+	u_int *uip = SCARG(uap, p);
+	u_int n, o = 0;
+	int error;
+
+	rw_enter_write(&sys_cas_lock);
+	error = copyin(uip, &o, sizeof(*uip));
+	if (error == 0 && o == SCARG(uap, e)) {
+		n = SCARG(uap, n);
+		error = copyout(&n, uip, sizeof(*uip));
+	}
+	rw_exit_write(&sys_cas_lock);
+
+	if (error) {
+		KERNEL_LOCK();
+		psignal(p, SIGSEGV);
+		KERNEL_UNLOCK();
+	}
+
+	*retval = o;
+	return (error);
+}
+
+int
+sys_cas_ulong(struct proc *p, void *v, register_t *retval)
+{
+	struct sys_cas_ulong_args /* {
+		syscallarg(u_int *) p;
+		syscallarg(u_int) e;
+		syscallarg(u_int) n;
+	} */ *uap = v;
+	u_long *uip = SCARG(uap, p);
+	u_long n, o = 0;
+	int error;
+
+	rw_enter_write(&sys_cas_lock);
+	error = copyin(uip, &o, sizeof(*uip));
+	if (error == 0 && o == SCARG(uap, e)) {
+		n = SCARG(uap, n);
+		error = copyout(&n, uip, sizeof(*uip));
+	}
+	rw_exit_write(&sys_cas_lock);
+
+	if (error) {
+		KERNEL_LOCK();
+		psignal(p, SIGSEGV);
+		KERNEL_UNLOCK();
+	}
+
+	*retval = o;
+	return (error);
+}
Index: arch/hppa/include/param.h
===================================================================
RCS file: /cvs/src/sys/arch/hppa/include/param.h,v
retrieving revision 1.45
diff -u -p -r1.45 param.h
--- arch/hppa/include/param.h	26 Mar 2013 05:04:10 -0000	1.45
+++ arch/hppa/include/param.h	26 Jun 2015 06:57:55 -0000
@@ -68,4 +68,6 @@
 #define	MACHINE_STACK_GROWS_UP	1		/* stack grows to higher addresses */
 #define	__SWAP_BROKEN
 
+#define SYS_CAS
+
 #endif /* _MACHINE_PARAM_H_ */
Index: kern/syscalls.master
===================================================================
RCS file: /cvs/src/sys/kern/syscalls.master,v
retrieving revision 1.153
diff -u -p -r1.153 syscalls.master
--- kern/syscalls.master	6 May 2015 11:20:07 -0000	1.153
+++ kern/syscalls.master	26 Jun 2015 06:58:06 -0000
@@ -303,8 +303,13 @@
 163	OBSOL		osetdomainname
 164	UNIMPL		ouname
 165	STD		{ int sys_sysarch(int op, void *parms); }
+#ifdef SYS_CAS
+166	STD NOLOCK	{ u_int sys_cas_uint(u_int *p, u_int e, u_int n); }
+167	STD NOLOCK	{ u_long sys_cas_ulong(u_long *p, u_long e, u_long n); }
+#else
 166	UNIMPL
 167	UNIMPL
+#endif
 168	UNIMPL
 169	OBSOL		semsys10
 170	OBSOL		msgsys10