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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
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 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
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 * - 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.
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 *
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
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * 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 address space areas backed by an ELF image.
36
 */
37
 
2000 decky 38
#include <lib/elf.h>
1424 jermar 39
#include <debug.h>
40
#include <arch/types.h>
41
#include <mm/as.h>
42
#include <mm/frame.h>
43
#include <mm/slab.h>
1426 jermar 44
#include <mm/page.h>
45
#include <genarch/mm/page_pt.h>
46
#include <genarch/mm/page_ht.h>
1424 jermar 47
#include <align.h>
48
#include <memstr.h>
49
#include <macros.h>
50
#include <arch.h>
51
 
2076 jermar 52
#ifdef CONFIG_VIRT_IDX_DCACHE
53
#include <arch/mm/cache.h>
54
#endif
55
 
1780 jermar 56
static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
57
static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
1426 jermar 58
static void elf_share(as_area_t *area);
1424 jermar 59
 
60
mem_backend_t elf_backend = {
61
    .page_fault = elf_page_fault,
62
    .frame_free = elf_frame_free,
1426 jermar 63
    .share = elf_share
1424 jermar 64
};
65
 
66
/** Service a page fault in the ELF backend address space area.
67
 *
68
 * The address space area and page tables must be already locked.
69
 *
70
 * @param area Pointer to the address space area.
71
 * @param addr Faulting virtual address.
72
 * @param access Access mode that caused the fault (i.e. read/write/exec).
73
 *
74
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
75
 */
1780 jermar 76
int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
1424 jermar 77
{
1425 jermar 78
    elf_header_t *elf = area->backend_data.elf;
79
    elf_segment_header_t *entry = area->backend_data.segment;
1426 jermar 80
    btree_node_t *leaf;
1780 jermar 81
    uintptr_t base, frame;
1424 jermar 82
    index_t i;
83
 
84
    if (!as_area_check_access(area, access))
85
        return AS_PF_FAULT;
86
 
87
    ASSERT((addr >= entry->p_vaddr) && (addr < entry->p_vaddr + entry->p_memsz));
88
    i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 89
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 90
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
1426 jermar 91
 
92
    if (area->sh_info) {
93
        bool found = false;
94
 
95
        /*
96
         * The address space area is shared.
97
         */
98
 
99
        mutex_lock(&area->sh_info->lock);
1780 jermar 100
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
1426 jermar 101
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
102
        if (!frame) {
103
            int i;
104
 
105
            /*
106
             * Workaround for valid NULL address.
107
             */
108
 
109
            for (i = 0; i < leaf->keys; i++) {
110
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
111
                    found = true;
112
                    break;
113
                }
114
            }
115
        }
116
        if (frame || found) {
1546 jermar 117
            frame_reference_add(ADDR2PFN(frame));
1426 jermar 118
            page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
119
            if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
120
                panic("Could not insert used space.\n");
121
            mutex_unlock(&area->sh_info->lock);
122
            return AS_PF_OK;
123
        }
124
    }
1424 jermar 125
 
1426 jermar 126
    /*
127
     * The area is either not shared or the pagemap does not contain the mapping.
128
     */
129
 
1424 jermar 130
    if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE < entry->p_vaddr + entry->p_filesz) {
131
        /*
132
         * Initialized portion of the segment. The memory is backed
133
         * directly by the content of the ELF image. Pages are
134
         * only copied if the segment is writable so that there
135
         * can be more instantions of the same memory ELF image
136
         * used at a time. Note that this could be later done
137
         * as COW.
138
         */
139
        if (entry->p_flags & PF_W) {
1780 jermar 140
            frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 141
            memcpy((void *) PA2KA(frame), (void *) (base + i*FRAME_SIZE), FRAME_SIZE);
1426 jermar 142
 
143
            if (area->sh_info) {
1546 jermar 144
                frame_reference_add(ADDR2PFN(frame));
1426 jermar 145
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
146
                    (void *) frame, leaf);
147
            }
148
 
1424 jermar 149
        } else {
150
            frame = KA2PA(base + i*FRAME_SIZE);
151
        }  
152
    } else if (ALIGN_DOWN(addr, PAGE_SIZE) >= ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
153
        /*
154
         * This is the uninitialized portion of the segment.
155
         * It is not physically present in the ELF image.
156
         * To resolve the situation, a frame must be allocated
157
         * and cleared.
158
         */
1780 jermar 159
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 160
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
1426 jermar 161
 
162
        if (area->sh_info) {
1546 jermar 163
            frame_reference_add(ADDR2PFN(frame));
1426 jermar 164
            btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
165
                (void *) frame, leaf);
166
        }
167
 
1424 jermar 168
    } else {
169
        size_t size;
170
        /*
171
         * The mixed case.
172
         * The lower part is backed by the ELF image and
173
         * the upper part is anonymous memory.
174
         */
175
        size = entry->p_filesz - (i<<PAGE_WIDTH);
1780 jermar 176
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 177
        memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
178
        memcpy((void *) PA2KA(frame), (void *) (base + i*FRAME_SIZE), size);
1426 jermar 179
 
180
        if (area->sh_info) {
1546 jermar 181
            frame_reference_add(ADDR2PFN(frame));
1426 jermar 182
            btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
183
                (void *) frame, leaf);
184
        }
185
 
1424 jermar 186
    }
187
 
1426 jermar 188
    if (area->sh_info)
189
        mutex_unlock(&area->sh_info->lock);
190
 
1424 jermar 191
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1426 jermar 192
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
193
        panic("Could not insert used space.\n");
1424 jermar 194
 
195
    return AS_PF_OK;
196
}
197
 
198
/** Free a frame that is backed by the ELF backend.
199
 *
200
 * The address space area and page tables must be already locked.
201
 *
202
 * @param area Pointer to the address space area.
203
 * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
204
 * @param frame Frame to be released.
205
 *
206
 */
1780 jermar 207
void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
1424 jermar 208
{
1425 jermar 209
    elf_header_t *elf = area->backend_data.elf;
210
    elf_segment_header_t *entry = area->backend_data.segment;
1780 jermar 211
    uintptr_t base;
1424 jermar 212
    index_t i;
213
 
214
    ASSERT((page >= entry->p_vaddr) && (page < entry->p_vaddr + entry->p_memsz));
215
    i = (page - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 216
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 217
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
218
 
219
    if (page + PAGE_SIZE < ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
220
        if (entry->p_flags & PF_W) {
221
            /*
222
             * Free the frame with the copy of writable segment data.
223
             */
1760 palkovsky 224
            frame_free(frame);
2076 jermar 225
#ifdef CONFIG_VIRT_IDX_DCACHE
226
                dcache_flush_frame(page, frame);
227
#endif
1424 jermar 228
        }
229
    } else {
230
        /*
231
         * The frame is either anonymous memory or the mixed case (i.e. lower
232
         * part is backed by the ELF image and the upper is anonymous).
233
         * In any case, a frame needs to be freed.
234
         */
1760 palkovsky 235
        frame_free(frame);
2076 jermar 236
#ifdef CONFIG_VIRT_IDX_DCACHE
237
            dcache_flush_frame(page, frame);
238
#endif
1424 jermar 239
    }
240
}
1426 jermar 241
 
242
/** Share ELF image backed address space area.
243
 *
244
 * If the area is writable, then all mapped pages are duplicated in the pagemap.
245
 * Otherwise only portions of the area that are not backed by the ELF image
246
 * are put into the pagemap.
247
 *
248
 * The address space and address space area must be locked prior to the call.
249
 *
250
 * @param area Address space area.
251
 */
252
void elf_share(as_area_t *area)
253
{
254
    elf_segment_header_t *entry = area->backend_data.segment;
255
    link_t *cur;
256
    btree_node_t *leaf, *node;
1780 jermar 257
    uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
1426 jermar 258
 
259
    /*
260
     * Find the node in which to start linear search.
261
     */
262
    if (area->flags & AS_AREA_WRITE) {
263
        node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
264
    } else {
265
        (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
266
        node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap, leaf);
267
        if (!node)
268
            node = leaf;
269
    }
270
 
271
    /*
272
     * Copy used anonymous portions of the area to sh_info's page map.
273
     */
274
    mutex_lock(&area->sh_info->lock);
275
    for (cur = &node->leaf_link; cur != &area->used_space.leaf_head; cur = cur->next) {
276
        int i;
277
 
278
        node = list_get_instance(cur, btree_node_t, leaf_link);
279
 
280
        for (i = 0; i < node->keys; i++) {
1780 jermar 281
            uintptr_t base = node->key[i];
1426 jermar 282
            count_t count = (count_t) node->value[i];
283
            int j;
284
 
285
            /*
286
             * Skip read-only areas of used space that are backed
287
             * by the ELF image.
288
             */
289
            if (!(area->flags & AS_AREA_WRITE))
290
                if (base + count*PAGE_SIZE <= start_anon)
291
                    continue;
292
 
293
            for (j = 0; j < count; j++) {
294
                pte_t *pte;
295
 
296
                /*
297
                 * Skip read-only pages that are backed by the ELF image.
298
                 */
299
                if (!(area->flags & AS_AREA_WRITE))
300
                    if (base + (j + 1)*PAGE_SIZE <= start_anon)
301
                        continue;
302
 
303
                page_table_lock(area->as, false);
304
                pte = page_mapping_find(area->as, base + j*PAGE_SIZE);
305
                ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
306
                btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,
307
                    (void *) PTE_GET_FRAME(pte), NULL);
308
                page_table_unlock(area->as, false);
1546 jermar 309
                frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte)));
1426 jermar 310
            }
311
 
312
        }
313
    }
314
    mutex_unlock(&area->sh_info->lock);
315
}
1702 cejka 316
 
1757 jermar 317
/** @}
1702 cejka 318
 */