1/*-
2 * Copyright (c) 2000 Peter Wemm
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
27__FBSDID("$FreeBSD$");
28
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/conf.h>
32#include <sys/kernel.h>
33#include <sys/lock.h>
34#include <sys/proc.h>
35#include <sys/mutex.h>
36#include <sys/mman.h>
37#include <sys/sysctl.h>
38
39#include <vm/vm.h>
40#include <vm/vm_object.h>
41#include <vm/vm_page.h>
42#include <vm/vm_pager.h>
43
44/* list of phys pager objects */
45static struct pagerlst phys_pager_object_list;
46/* protect access to phys_pager_object_list */
47static struct mtx phys_pager_mtx;
48
49static void
50phys_pager_init(void)
51{
52
53	TAILQ_INIT(&phys_pager_object_list);
54	mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
55}
56
57/*
58 * MPSAFE
59 */
60static vm_object_t
61phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
62    vm_ooffset_t foff, struct ucred *cred)
63{
64	vm_object_t object, object1;
65	vm_pindex_t pindex;
66
67	/*
68	 * Offset should be page aligned.
69	 */
70	if (foff & PAGE_MASK)
71		return (NULL);
72
73	pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
74
75	if (handle != NULL) {
76		mtx_lock(&phys_pager_mtx);
77		/*
78		 * Look up pager, creating as necessary.
79		 */
80		object1 = NULL;
81		object = vm_pager_object_lookup(&phys_pager_object_list, handle);
82		if (object == NULL) {
83			/*
84			 * Allocate object and associate it with the pager.
85			 */
86			mtx_unlock(&phys_pager_mtx);
87			object1 = vm_object_allocate(OBJT_PHYS, pindex);
88			mtx_lock(&phys_pager_mtx);
89			object = vm_pager_object_lookup(&phys_pager_object_list,
90			    handle);
91			if (object != NULL) {
92				/*
93				 * We raced with other thread while
94				 * allocating object.
95				 */
96				if (pindex > object->size)
97					object->size = pindex;
98			} else {
99				object = object1;
100				object1 = NULL;
101				object->handle = handle;
102				TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
103				    pager_object_list);
104			}
105		} else {
106			if (pindex > object->size)
107				object->size = pindex;
108		}
109		mtx_unlock(&phys_pager_mtx);
110		vm_object_deallocate(object1);
111	} else {
112		object = vm_object_allocate(OBJT_PHYS, pindex);
113	}
114
115	return (object);
116}
117
118/*
119 * MPSAFE
120 */
121static void
122phys_pager_dealloc(vm_object_t object)
123{
124
125	if (object->handle != NULL) {
126		VM_OBJECT_UNLOCK(object);
127		mtx_lock(&phys_pager_mtx);
128		TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
129		mtx_unlock(&phys_pager_mtx);
130		VM_OBJECT_LOCK(object);
131	}
132}
133
134/*
135 * Fill as many pages as vm_fault has allocated for us.
136 */
137static int
138phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
139{
140	int i;
141
142	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
143	for (i = 0; i < count; i++) {
144		if (m[i]->valid == 0) {
145			if ((m[i]->flags & PG_ZERO) == 0)
146				pmap_zero_page(m[i]);
147			m[i]->valid = VM_PAGE_BITS_ALL;
148		}
149		KASSERT(m[i]->valid == VM_PAGE_BITS_ALL,
150		    ("phys_pager_getpages: partially valid page %p", m[i]));
151		KASSERT(m[i]->dirty == 0,
152		    ("phys_pager_getpages: dirty page %p", m[i]));
153		/* The requested page must remain busy, the others not. */
154		if (i == reqpage)
155			vm_page_flash(m[i]);
156		else
157			vm_page_wakeup(m[i]);
158	}
159	return (VM_PAGER_OK);
160}
161
162static void
163phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
164		    int *rtvals)
165{
166
167	panic("phys_pager_putpage called");
168}
169
170/*
171 * Implement a pretty aggressive clustered getpages strategy.  Hint that
172 * everything in an entire 4MB window should be prefaulted at once.
173 *
174 * XXX 4MB (1024 slots per page table page) is convenient for x86,
175 * but may not be for other arches.
176 */
177#ifndef PHYSCLUSTER
178#define PHYSCLUSTER 1024
179#endif
180static boolean_t
181phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
182		   int *after)
183{
184	vm_pindex_t base, end;
185
186	base = pindex & (~(PHYSCLUSTER - 1));
187	end = base + (PHYSCLUSTER - 1);
188	if (before != NULL)
189		*before = pindex - base;
190	if (after != NULL)
191		*after = end - pindex;
192	return (TRUE);
193}
194
195struct pagerops physpagerops = {
196	.pgo_init =	phys_pager_init,
197	.pgo_alloc =	phys_pager_alloc,
198	.pgo_dealloc = 	phys_pager_dealloc,
199	.pgo_getpages =	phys_pager_getpages,
200	.pgo_putpages =	phys_pager_putpages,
201	.pgo_haspage =	phys_pager_haspage,
202};
203