sf_buf.h revision 190681 
1/*-
2 * Copyright (c) 2003 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: head/sys/powerpc/include/sf_buf.h 190681 2009-04-04 00:22:44Z nwhitehorn $
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#include <machine/md_var.h>
36#include <sys/queue.h>
37
38struct vm_page;
39
40struct sf_buf {
41	LIST_ENTRY(sf_buf) list_entry;	/* list of buffers */
42	TAILQ_ENTRY(sf_buf) free_entry;	/* list of buffers */
43	struct		vm_page *m;	/* currently mapped page */
44	vm_offset_t	kva;		/* va of mapping */
45	int		ref_count;	/* usage of this mapping */
46};
47
48/*
49 * On 32-bit OEA, the only purpose for which sf_buf is used is to implement
50 * an opaque pointer required by the machine-independent parts of the kernel.
51 * That pointer references the vm_page that is "mapped" by the sf_buf.  The
52 * actual mapping is provided by the direct virtual-to-physical mapping.
53 *
54 * On OEA64 and Book-E, we need to do something a little more complicated. Use
55 * the runtime-detected hw_direct_map to pick between the two cases. Our
56 * friends in vm_machdep.c will do the same to ensure nothing gets confused.
57 */
58
59static __inline vm_offset_t
60sf_buf_kva(struct sf_buf *sf)
61{
62	if (hw_direct_map)
63		return (VM_PAGE_TO_PHYS((vm_page_t)sf));
64
65	return (sf->kva);
66}
67
68static __inline struct vm_page *
69sf_buf_page(struct sf_buf *sf)
70{
71	if (hw_direct_map)
72		return ((vm_page_t)sf);
73
74	return (sf->m);
75}
76
77#endif /* !_MACHINE_SF_BUF_H_ */
78