xref: /freebsd/sys/amd64/include/sf_buf.h (revision d4ae33f0721c1b170fe37d97e395228ffcfb3f80)
1 /*-
2  * Copyright (c) 2003, 2005 Alan L. Cox <alc@cs.rice.edu>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #ifndef _MACHINE_SF_BUF_H_
30 #define _MACHINE_SF_BUF_H_
31 
32 #include <vm/vm.h>
33 #include <vm/vm_param.h>
34 #include <vm/vm_page.h>
35 
36 /*
37  * On this machine, the only purpose for which sf_buf is used is to implement
38  * an opaque pointer required by the machine-independent parts of the kernel.
39  * That pointer references the vm_page that is "mapped" by the sf_buf.  The
40  * actual mapping is provided by the direct virtual-to-physical mapping.
41  */
42 struct sf_buf;
43 
44 static inline struct sf_buf *
45 sf_buf_alloc(struct vm_page *m, int pri)
46 {
47 
48 	return ((struct sf_buf *)m);
49 }
50 
51 static inline void
52 sf_buf_free(struct sf_buf *sf)
53 {
54 }
55 
56 static __inline vm_offset_t
57 sf_buf_kva(struct sf_buf *sf)
58 {
59 
60 	return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS((vm_page_t)sf)));
61 }
62 
63 static __inline vm_page_t
64 sf_buf_page(struct sf_buf *sf)
65 {
66 
67 	return ((vm_page_t)sf);
68 }
69 
70 #endif /* !_MACHINE_SF_BUF_H_ */
71