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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
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 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
 *
2292 hudecek 74
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.
75
 *     serviced).
1424 jermar 76
 */
1780 jermar 77
int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
1424 jermar 78
{
1425 jermar 79
    elf_header_t *elf = area->backend_data.elf;
80
    elf_segment_header_t *entry = area->backend_data.segment;
1426 jermar 81
    btree_node_t *leaf;
1780 jermar 82
    uintptr_t base, frame;
1424 jermar 83
    index_t i;
2292 hudecek 84
    bool dirty = false;
1424 jermar 85
 
86
    if (!as_area_check_access(area, access))
87
        return AS_PF_FAULT;
88
 
2292 hudecek 89
    ASSERT((addr >= entry->p_vaddr) &&
90
        (addr < entry->p_vaddr + entry->p_memsz));
1424 jermar 91
    i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 92
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 93
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
1426 jermar 94
 
95
    if (area->sh_info) {
96
        bool found = false;
97
 
98
        /*
99
         * The address space area is shared.
100
         */
101
 
102
        mutex_lock(&area->sh_info->lock);
1780 jermar 103
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
1426 jermar 104
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
105
        if (!frame) {
106
            int i;
107
 
108
            /*
109
             * Workaround for valid NULL address.
110
             */
111
 
112
            for (i = 0; i < leaf->keys; i++) {
2292 hudecek 113
                if (leaf->key[i] ==
114
                    ALIGN_DOWN(addr, PAGE_SIZE)) {
1426 jermar 115
                    found = true;
116
                    break;
117
                }
118
            }
119
        }
120
        if (frame || found) {
1546 jermar 121
            frame_reference_add(ADDR2PFN(frame));
2292 hudecek 122
            page_mapping_insert(AS, addr, frame,
123
                as_area_get_flags(area));
124
            if (!used_space_insert(area,
125
                ALIGN_DOWN(addr, PAGE_SIZE), 1))
1426 jermar 126
                panic("Could not insert used space.\n");
127
            mutex_unlock(&area->sh_info->lock);
128
            return AS_PF_OK;
129
        }
130
    }
1424 jermar 131
 
1426 jermar 132
    /*
2292 hudecek 133
     * The area is either not shared or the pagemap does not contain the
134
     * mapping.
1426 jermar 135
     */
136
 
2292 hudecek 137
    if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <
138
        entry->p_vaddr + entry->p_filesz) {
1424 jermar 139
        /*
140
         * Initialized portion of the segment. The memory is backed
141
         * directly by the content of the ELF image. Pages are
142
         * only copied if the segment is writable so that there
143
         * can be more instantions of the same memory ELF image
144
         * used at a time. Note that this could be later done
145
         * as COW.
146
         */
147
        if (entry->p_flags & PF_W) {
1780 jermar 148
            frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
2292 hudecek 149
            memcpy((void *) PA2KA(frame),
150
                (void *) (base + i * FRAME_SIZE), FRAME_SIZE);
151
            dirty = true;
152
 
1426 jermar 153
            if (area->sh_info) {
1546 jermar 154
                frame_reference_add(ADDR2PFN(frame));
2292 hudecek 155
                btree_insert(&area->sh_info->pagemap,
156
                    ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
157
                    (void *) frame, leaf);
1426 jermar 158
            }
159
 
1424 jermar 160
        } else {
161
            frame = KA2PA(base + i*FRAME_SIZE);
162
        }  
2292 hudecek 163
    } else if (ALIGN_DOWN(addr, PAGE_SIZE) >=
164
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
1424 jermar 165
        /*
166
         * This is the uninitialized portion of the segment.
167
         * It is not physically present in the ELF image.
168
         * To resolve the situation, a frame must be allocated
169
         * and cleared.
170
         */
1780 jermar 171
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 172
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
2292 hudecek 173
        dirty = true;
1426 jermar 174
 
175
        if (area->sh_info) {
1546 jermar 176
            frame_reference_add(ADDR2PFN(frame));
2292 hudecek 177
            btree_insert(&area->sh_info->pagemap,
178
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
179
                (void *) frame, leaf);
1426 jermar 180
        }
181
 
1424 jermar 182
    } else {
183
        size_t size;
184
        /*
185
         * The mixed case.
186
         * The lower part is backed by the ELF image and
187
         * the upper part is anonymous memory.
188
         */
189
        size = entry->p_filesz - (i<<PAGE_WIDTH);
1780 jermar 190
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 191
        memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
2292 hudecek 192
        memcpy((void *) PA2KA(frame), (void *) (base + i * FRAME_SIZE),
193
            size);
194
        dirty = true;
1426 jermar 195
 
196
        if (area->sh_info) {
1546 jermar 197
            frame_reference_add(ADDR2PFN(frame));
2292 hudecek 198
            btree_insert(&area->sh_info->pagemap,
199
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
200
                (void *) frame, leaf);
1426 jermar 201
        }
202
 
1424 jermar 203
    }
204
 
1426 jermar 205
    if (area->sh_info)
206
        mutex_unlock(&area->sh_info->lock);
207
 
1424 jermar 208
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1426 jermar 209
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
210
        panic("Could not insert used space.\n");
1424 jermar 211
 
212
    return AS_PF_OK;
213
}
214
 
215
/** Free a frame that is backed by the ELF backend.
216
 *
217
 * The address space area and page tables must be already locked.
218
 *
219
 * @param area Pointer to the address space area.
220
 * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
221
 * @param frame Frame to be released.
222
 *
223
 */
1780 jermar 224
void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
1424 jermar 225
{
1425 jermar 226
    elf_header_t *elf = area->backend_data.elf;
227
    elf_segment_header_t *entry = area->backend_data.segment;
1780 jermar 228
    uintptr_t base;
1424 jermar 229
    index_t i;
230
 
2292 hudecek 231
    ASSERT((page >= entry->p_vaddr) &&
232
        (page < entry->p_vaddr + entry->p_memsz));
1424 jermar 233
    i = (page - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 234
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 235
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
236
 
2292 hudecek 237
    if (page + PAGE_SIZE <
238
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
1424 jermar 239
        if (entry->p_flags & PF_W) {
240
            /*
2292 hudecek 241
             * Free the frame with the copy of writable segment
242
             * data.
1424 jermar 243
             */
1760 palkovsky 244
            frame_free(frame);
1424 jermar 245
        }
246
    } else {
247
        /*
2292 hudecek 248
         * The frame is either anonymous memory or the mixed case (i.e.
249
         * lower part is backed by the ELF image and the upper is
250
         * anonymous). In any case, a frame needs to be freed.
251
         */
252
        frame_free(frame);
1424 jermar 253
    }
254
}
1426 jermar 255
 
256
/** Share ELF image backed address space area.
257
 *
258
 * If the area is writable, then all mapped pages are duplicated in the pagemap.
259
 * Otherwise only portions of the area that are not backed by the ELF image
260
 * are put into the pagemap.
261
 *
262
 * The address space and address space area must be locked prior to the call.
263
 *
264
 * @param area Address space area.
265
 */
266
void elf_share(as_area_t *area)
267
{
268
    elf_segment_header_t *entry = area->backend_data.segment;
269
    link_t *cur;
270
    btree_node_t *leaf, *node;
1780 jermar 271
    uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
1426 jermar 272
 
273
    /*
274
     * Find the node in which to start linear search.
275
     */
276
    if (area->flags & AS_AREA_WRITE) {
2292 hudecek 277
        node = list_get_instance(area->used_space.leaf_head.next,
278
            btree_node_t, leaf_link);
1426 jermar 279
    } else {
280
        (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
2292 hudecek 281
        node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,
282
            leaf);
1426 jermar 283
        if (!node)
284
            node = leaf;
285
    }
286
 
287
    /*
288
     * Copy used anonymous portions of the area to sh_info's page map.
289
     */
290
    mutex_lock(&area->sh_info->lock);
2292 hudecek 291
    for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;
292
        cur = cur->next) {
1426 jermar 293
        int i;
294
 
295
        node = list_get_instance(cur, btree_node_t, leaf_link);
296
 
297
        for (i = 0; i < node->keys; i++) {
1780 jermar 298
            uintptr_t base = node->key[i];
1426 jermar 299
            count_t count = (count_t) node->value[i];
300
            int j;
301
 
302
            /*
303
             * Skip read-only areas of used space that are backed
304
             * by the ELF image.
305
             */
306
            if (!(area->flags & AS_AREA_WRITE))
307
                if (base + count*PAGE_SIZE <= start_anon)
308
                    continue;
309
 
310
            for (j = 0; j < count; j++) {
311
                pte_t *pte;
312
 
313
                /*
2292 hudecek 314
                 * Skip read-only pages that are backed by the
315
                 * ELF image.
1426 jermar 316
                 */
317
                if (!(area->flags & AS_AREA_WRITE))
2292 hudecek 318
                    if (base + (j + 1) * PAGE_SIZE <=
319
                        start_anon)
1426 jermar 320
                        continue;
321
 
322
                page_table_lock(area->as, false);
2292 hudecek 323
                pte = page_mapping_find(area->as,
324
                    base + j * PAGE_SIZE);
325
                ASSERT(pte && PTE_VALID(pte) &&
326
                    PTE_PRESENT(pte));
327
                btree_insert(&area->sh_info->pagemap,
328
                    (base + j * PAGE_SIZE) - area->base,
1426 jermar 329
                    (void *) PTE_GET_FRAME(pte), NULL);
330
                page_table_unlock(area->as, false);
2292 hudecek 331
 
332
                pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
333
                frame_reference_add(pfn);
1426 jermar 334
            }
335
 
336
        }
337
    }
338
    mutex_unlock(&area->sh_info->lock);
339
}
1702 cejka 340
 
1757 jermar 341
/** @}
1702 cejka 342
 */