diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
--- a/lib/libc/include/libc_private.h
+++ b/lib/libc/include/libc_private.h
@@ -344,7 +344,7 @@
 int		__sys_close(int);
 int		__sys_close_range(unsigned, unsigned, int);
 int		__sys_connect(int, const struct sockaddr *, __socklen_t);
-int		__sys_fcntl(int, int, ...);
+int		__sys_fcntl(int, int, __intptr_t);
 int		__sys_fdatasync(int);
 int		__sys_fstat(int fd, struct stat *);
 int		__sys_fstatfs(int fd, struct statfs *);
diff --git a/lib/libthr/thread/thr_syscalls.c b/lib/libthr/thread/thr_syscalls.c
--- a/lib/libthr/thread/thr_syscalls.c
+++ b/lib/libthr/thread/thr_syscalls.c
@@ -198,10 +198,10 @@
 	va_start(ap, cmd);
 	if (cmd == F_OSETLKW || cmd == F_SETLKW) {
 		_thr_cancel_enter(curthread);
-		ret = __sys_fcntl(fd, cmd, va_arg(ap, void *));
+		ret = __sys_fcntl(fd, cmd, (intptr_t)va_arg(ap, void *));
 		_thr_cancel_leave(curthread, ret == -1);
 	} else {
-		ret = __sys_fcntl(fd, cmd, va_arg(ap, void *));
+		ret = __sys_fcntl(fd, cmd, (intptr_t)va_arg(ap, void *));
 	}
 	va_end(ap);
 
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -3942,7 +3942,7 @@
 int
 freebsd32_fcntl(struct thread *td, struct freebsd32_fcntl_args *uap)
 {
-	long tmp;
+	intptr_t tmp;
 
 	switch (uap->cmd) {
 	/*
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -414,7 +414,7 @@
 }
 
 int
-kern_fcntl_freebsd(struct thread *td, int fd, int cmd, long arg)
+kern_fcntl_freebsd(struct thread *td, int fd, int cmd, intptr_t arg)
 {
 	struct flock fl;
 	struct __oflock ofl;
@@ -430,7 +430,7 @@
 		/*
 		 * Convert old flock structure to new.
 		 */
-		error = copyin((void *)(intptr_t)arg, &ofl, sizeof(ofl));
+		error = copyin((void *)arg, &ofl, sizeof(ofl));
 		fl.l_start = ofl.l_start;
 		fl.l_len = ofl.l_len;
 		fl.l_pid = ofl.l_pid;
@@ -455,7 +455,7 @@
 	case F_SETLK:
 	case F_SETLKW:
 	case F_SETLK_REMOTE:
-		error = copyin((void *)(intptr_t)arg, &fl, sizeof(fl));
+		error = copyin((void *)arg, &fl, sizeof(fl));
 		arg1 = (intptr_t)&fl;
 		break;
 	default:
@@ -473,9 +473,9 @@
 		ofl.l_pid = fl.l_pid;
 		ofl.l_type = fl.l_type;
 		ofl.l_whence = fl.l_whence;
-		error = copyout(&ofl, (void *)(intptr_t)arg, sizeof(ofl));
+		error = copyout(&ofl, (void *)arg, sizeof(ofl));
 	} else if (cmd == F_GETLK) {
-		error = copyout(&fl, (void *)(intptr_t)arg, sizeof(fl));
+		error = copyout(&fl, (void *)arg, sizeof(fl));
 	}
 	return (error);
 }
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -616,7 +616,7 @@
 		int fcntl(
 		    int fd,
 		    int cmd,
-		    long arg
+		    intptr_t arg
 		);
 	}
 ; XXX should be { int fcntl(int fd, int cmd, ...); }