Subversion Repositories HelenOS

Rev

Rev 2089 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1424 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2006 Jakub Jermar
1424 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
 
1757 jermar 29
/** @addtogroup genericmm
1702 cejka 30
 * @{
31
 */
32
 
1424 jermar 33
/**
1702 cejka 34
 * @file
1424 jermar 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
 
2076 jermar 53
#ifdef CONFIG_VIRT_IDX_DCACHE
54
#include <arch/mm/cache.h>
55
#endif
56
 
1780 jermar 57
static int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
58
static void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
1424 jermar 59
static void anon_share(as_area_t *area);
60
 
61
mem_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. serviced).
76
 */
1780 jermar 77
int anon_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
1424 jermar 78
{
1780 jermar 79
    uintptr_t frame;
1424 jermar 80
 
81
    if (!as_area_check_access(area, access))
82
        return AS_PF_FAULT;
83
 
84
    if (area->sh_info) {
85
        btree_node_t *leaf;
86
 
87
        /*
88
         * The area is shared, chances are that the mapping can be found
89
         * in the pagemap of the address space area share info structure.
90
         * In the case that the pagemap does not contain the respective
91
         * mapping, a new frame is allocated and the mapping is created.
92
         */
93
        mutex_lock(&area->sh_info->lock);
1780 jermar 94
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
1424 jermar 95
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
96
        if (!frame) {
97
            bool allocate = true;
98
            int i;
99
 
100
            /*
101
             * Zero can be returned as a valid frame address.
102
             * Just a small workaround.
103
             */
104
            for (i = 0; i < leaf->keys; i++) {
105
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
106
                    allocate = false;
107
                    break;
108
                }
109
            }
110
            if (allocate) {
1780 jermar 111
                frame = (uintptr_t) frame_alloc(ONE_FRAME, 0);
1424 jermar 112
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
113
 
114
                /*
115
                 * Insert the address of the newly allocated frame to the pagemap.
116
                 */
117
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);
118
            }
119
        }
1545 jermar 120
        frame_reference_add(ADDR2PFN(frame));
1424 jermar 121
        mutex_unlock(&area->sh_info->lock);
122
    } else {
123
 
124
        /*
125
         * In general, there can be several reasons that
126
         * can have caused this fault.
127
         *
128
         * - non-existent mapping: the area is an anonymous
129
         *   area (e.g. heap or stack) and so far has not been
130
         *   allocated a frame for the faulting page
131
         *
132
         * - non-present mapping: another possibility,
133
         *   currently not implemented, would be frame
134
         *   reuse; when this becomes a possibility,
135
         *   do not forget to distinguish between
136
         *   the different causes
137
         */
1954 jermar 138
        frame = (uintptr_t) frame_alloc(ONE_FRAME, 0);
1424 jermar 139
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
140
    }
141
 
142
    /*
143
     * Map 'page' to 'frame'.
144
     * Note that TLB shootdown is not attempted as only new information is being
145
     * inserted into page tables.
146
     */
147
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
148
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
149
        panic("Could not insert used space.\n");
150
 
151
    return AS_PF_OK;
152
}
153
 
154
/** Free a frame that is backed by the anonymous memory backend.
155
 *
156
 * The address space area and page tables must be already locked.
157
 *
158
 * @param area Ignored.
2076 jermar 159
 * @param page Virtual address of the page corresponding to the frame.
1424 jermar 160
 * @param frame Frame to be released.
161
 */
1780 jermar 162
void anon_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
1424 jermar 163
{
1760 palkovsky 164
    frame_free(frame);
2076 jermar 165
#ifdef CONFIG_VIRT_IDX_DCACHE
166
    dcache_flush_frame(page, frame);
167
#endif
1424 jermar 168
}
169
 
170
/** Share the anonymous address space area.
171
 *
172
 * Sharing of anonymous area is done by duplicating its entire mapping
173
 * to the pagemap. Page faults will primarily search for frames there.
174
 *
1426 jermar 175
 * The address space and address space area must be already locked.
1424 jermar 176
 *
177
 * @param area Address space area to be shared.
178
 */
179
void anon_share(as_area_t *area)
180
{
181
    link_t *cur;
182
 
183
    /*
184
     * Copy used portions of the area to sh_info's page map.
185
     */
186
    mutex_lock(&area->sh_info->lock);
187
    for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {
188
        btree_node_t *node;
189
        int i;
190
 
191
        node = list_get_instance(cur, btree_node_t, leaf_link);
192
        for (i = 0; i < node->keys; i++) {
1780 jermar 193
            uintptr_t base = node->key[i];
1424 jermar 194
            count_t count = (count_t) node->value[i];
195
            int j;
196
 
197
            for (j = 0; j < count; j++) {
198
                pte_t *pte;
199
 
200
                page_table_lock(area->as, false);
201
                pte = page_mapping_find(area->as, base + j*PAGE_SIZE);
202
                ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
203
                btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,
204
                    (void *) PTE_GET_FRAME(pte), NULL);
205
                page_table_unlock(area->as, false);
1545 jermar 206
                frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte)));
1424 jermar 207
            }
208
 
209
        }
210
    }
211
    mutex_unlock(&area->sh_info->lock);
212
}
1702 cejka 213
 
1757 jermar 214
/** @}
1702 cejka 215
 */