source: mainline/kernel/generic/src/mm/backend_anon.c@ e32e092

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since e32e092 was e32e092, checked in by Jiri Svoboda <jirik.svoboda@…>, 17 years ago

Declare arguments for memstr.h operations as pointers instead of uintptr_t.
  • Property mode set to 100644
File size: 6.6 KB
Line 
1/*
2 * Copyright (c) 2006 Jakub Jermar
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 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup genericmm
30 * @{
31 */
32
33/**
34 * @file
35 * @brief Backend for anonymous memory address space areas.
36 *
37 */
38
39#include <mm/as.h>
40#include <mm/page.h>
41#include <genarch/mm/page_pt.h>
42#include <genarch/mm/page_ht.h>
43#include <mm/frame.h>
44#include <mm/slab.h>
45#include <synch/mutex.h>
46#include <adt/list.h>
47#include <adt/btree.h>
48#include <errno.h>
49#include <arch/types.h>
50#include <align.h>
51#include <arch.h>
52
53#ifdef CONFIG_VIRT_IDX_DCACHE
54#include <arch/mm/cache.h>
55#endif
56
57static int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
58static void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
59static void anon_share(as_area_t *area);
60
61mem_backend_t anon_backend = {
62 .page_fault = anon_page_fault,
63 .frame_free = anon_frame_free,
64 .share = anon_share
65};
66
67/** Service a page fault in the anonymous memory address space area.
68 *
69 * The address space area and page tables must be already locked.
70 *
71 * @param area Pointer to the address space area.
72 * @param addr Faulting virtual address.
73 * @param access Access mode that caused the fault (i.e. read/write/exec).
74 *
75 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.
76 * serviced).
77 */
78int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
79{
80 uintptr_t frame;
81 bool dirty = false;
82
83 if (!as_area_check_access(area, access))
84 return AS_PF_FAULT;
85
86 if (area->sh_info) {
87 btree_node_t *leaf;
88
89 /*
90 * The area is shared, chances are that the mapping can be found
91 * in the pagemap of the address space area share info
92 * structure.
93 * In the case that the pagemap does not contain the respective
94 * mapping, a new frame is allocated and the mapping is created.
95 */
96 mutex_lock(&area->sh_info->lock);
97 frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
98 ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
99 if (!frame) {
100 bool allocate = true;
101 unsigned int i;
102
103 /*
104 * Zero can be returned as a valid frame address.
105 * Just a small workaround.
106 */
107 for (i = 0; i < leaf->keys; i++) {
108 if (leaf->key[i] ==
109 ALIGN_DOWN(addr, PAGE_SIZE)) {
110 allocate = false;
111 break;
112 }
113 }
114 if (allocate) {
115 frame = (uintptr_t) frame_alloc(ONE_FRAME, 0);
116 memsetb((void *) PA2KA(frame), FRAME_SIZE, 0);
117 dirty = true;
118
119 /*
120 * Insert the address of the newly allocated
121 * frame to the pagemap.
122 */
123 btree_insert(&area->sh_info->pagemap,
124 ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
125 (void *) frame, leaf);
126 }
127 }
128 frame_reference_add(ADDR2PFN(frame));
129 mutex_unlock(&area->sh_info->lock);
130 } else {
131
132 /*
133 * In general, there can be several reasons that
134 * can have caused this fault.
135 *
136 * - non-existent mapping: the area is an anonymous
137 * area (e.g. heap or stack) and so far has not been
138 * allocated a frame for the faulting page
139 *
140 * - non-present mapping: another possibility,
141 * currently not implemented, would be frame
142 * reuse; when this becomes a possibility,
143 * do not forget to distinguish between
144 * the different causes
145 */
146 frame = (uintptr_t) frame_alloc(ONE_FRAME, 0);
147 memsetb((void *) PA2KA(frame), FRAME_SIZE, 0);
148 dirty = true;
149 }
150
151 /*
152 * Map 'page' to 'frame'.
153 * Note that TLB shootdown is not attempted as only new information is
154 * being inserted into page tables.
155 */
156 page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
157 if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
158 panic("Could not insert used space.\n");
159
160 return AS_PF_OK;
161}
162
163/** Free a frame that is backed by the anonymous memory backend.
164 *
165 * The address space area and page tables must be already locked.
166 *
167 * @param area Ignored.
168 * @param page Virtual address of the page corresponding to the frame.
169 * @param frame Frame to be released.
170 */
171void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
172{
173 frame_free(frame);
174}
175
176/** Share the anonymous address space area.
177 *
178 * Sharing of anonymous area is done by duplicating its entire mapping
179 * to the pagemap. Page faults will primarily search for frames there.
180 *
181 * The address space and address space area must be already locked.
182 *
183 * @param area Address space area to be shared.
184 */
185void anon_share(as_area_t *area)
186{
187 link_t *cur;
188
189 /*
190 * Copy used portions of the area to sh_info's page map.
191 */
192 mutex_lock(&area->sh_info->lock);
193 for (cur = area->used_space.leaf_head.next;
194 cur != &area->used_space.leaf_head; cur = cur->next) {
195 btree_node_t *node;
196 unsigned int i;
197
198 node = list_get_instance(cur, btree_node_t, leaf_link);
199 for (i = 0; i < node->keys; i++) {
200 uintptr_t base = node->key[i];
201 count_t count = (count_t) node->value[i];
202 unsigned int j;
203
204 for (j = 0; j < count; j++) {
205 pte_t *pte;
206
207 page_table_lock(area->as, false);
208 pte = page_mapping_find(area->as,
209 base + j * PAGE_SIZE);
210 ASSERT(pte && PTE_VALID(pte) &&
211 PTE_PRESENT(pte));
212 btree_insert(&area->sh_info->pagemap,
213 (base + j * PAGE_SIZE) - area->base,
214 (void *) PTE_GET_FRAME(pte), NULL);
215 page_table_unlock(area->as, false);
216
217 pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
218 frame_reference_add(pfn);
219 }
220
221 }
222 }
223 mutex_unlock(&area->sh_info->lock);
224}
225
226/** @}
227 */
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