1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2003, 2005 Alan L. Cox <alc@cs.rice.edu>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #ifndef _MACHINE_SF_BUF_H_
30 #define _MACHINE_SF_BUF_H_
31
32 #ifdef __amd64__
33 /*
34 * On this machine, the only purpose for which sf_buf is used is to implement
35 * an opaque pointer required by the machine-independent parts of the kernel.
36 * That pointer references the vm_page that is "mapped" by the sf_buf. The
37 * actual mapping is provided by the direct virtual-to-physical mapping.
38 */
39 static inline vm_offset_t
sf_buf_kva(struct sf_buf * sf)40 sf_buf_kva(struct sf_buf *sf)
41 {
42
43 return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS((vm_page_t)sf)));
44 }
45
46 static inline vm_page_t
sf_buf_page(struct sf_buf * sf)47 sf_buf_page(struct sf_buf *sf)
48 {
49
50 return ((vm_page_t)sf);
51 }
52 #endif /* __amd64__ */
53 #endif /* !_MACHINE_SF_BUF_H_ */
54