Subversion Repositories HelenOS

Rev

Rev 2089 | Rev 2141 | 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 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
 *
2132 jermar 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;
84
 
85
    if (!as_area_check_access(area, access))
86
        return AS_PF_FAULT;
87
 
2132 jermar 88
    ASSERT((addr >= entry->p_vaddr) &&
89
        (addr < entry->p_vaddr + entry->p_memsz));
1424 jermar 90
    i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 91
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 92
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
1426 jermar 93
 
94
    if (area->sh_info) {
95
        bool found = false;
96
 
97
        /*
98
         * The address space area is shared.
99
         */
100
 
101
        mutex_lock(&area->sh_info->lock);
1780 jermar 102
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
1426 jermar 103
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
104
        if (!frame) {
105
            int i;
106
 
107
            /*
108
             * Workaround for valid NULL address.
109
             */
110
 
111
            for (i = 0; i < leaf->keys; i++) {
2132 jermar 112
                if (leaf->key[i] ==
113
                    ALIGN_DOWN(addr, PAGE_SIZE)) {
1426 jermar 114
                    found = true;
115
                    break;
116
                }
117
            }
118
        }
119
        if (frame || found) {
1546 jermar 120
            frame_reference_add(ADDR2PFN(frame));
2132 jermar 121
            page_mapping_insert(AS, addr, frame,
122
                as_area_get_flags(area));
123
            if (!used_space_insert(area,
124
                ALIGN_DOWN(addr, PAGE_SIZE), 1))
1426 jermar 125
                panic("Could not insert used space.\n");
126
            mutex_unlock(&area->sh_info->lock);
127
            return AS_PF_OK;
128
        }
129
    }
1424 jermar 130
 
1426 jermar 131
    /*
2132 jermar 132
     * The area is either not shared or the pagemap does not contain the
133
     * mapping.
1426 jermar 134
     */
135
 
2132 jermar 136
    if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <
137
        entry->p_vaddr + entry->p_filesz) {
1424 jermar 138
        /*
139
         * Initialized portion of the segment. The memory is backed
140
         * directly by the content of the ELF image. Pages are
141
         * only copied if the segment is writable so that there
142
         * can be more instantions of the same memory ELF image
143
         * used at a time. Note that this could be later done
144
         * as COW.
145
         */
146
        if (entry->p_flags & PF_W) {
1780 jermar 147
            frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
2132 jermar 148
            memcpy((void *) PA2KA(frame),
149
                (void *) (base + i * FRAME_SIZE), FRAME_SIZE);
1426 jermar 150
 
151
            if (area->sh_info) {
1546 jermar 152
                frame_reference_add(ADDR2PFN(frame));
2132 jermar 153
                btree_insert(&area->sh_info->pagemap,
154
                    ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
155
                    (void *) frame, leaf);
1426 jermar 156
            }
157
 
1424 jermar 158
        } else {
159
            frame = KA2PA(base + i*FRAME_SIZE);
160
        }  
2132 jermar 161
    } else if (ALIGN_DOWN(addr, PAGE_SIZE) >=
162
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
1424 jermar 163
        /*
164
         * This is the uninitialized portion of the segment.
165
         * It is not physically present in the ELF image.
166
         * To resolve the situation, a frame must be allocated
167
         * and cleared.
168
         */
1780 jermar 169
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 170
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
1426 jermar 171
 
172
        if (area->sh_info) {
1546 jermar 173
            frame_reference_add(ADDR2PFN(frame));
2132 jermar 174
            btree_insert(&area->sh_info->pagemap,
175
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
176
                (void *) frame, leaf);
1426 jermar 177
        }
178
 
1424 jermar 179
    } else {
180
        size_t size;
181
        /*
182
         * The mixed case.
183
         * The lower part is backed by the ELF image and
184
         * the upper part is anonymous memory.
185
         */
186
        size = entry->p_filesz - (i<<PAGE_WIDTH);
1780 jermar 187
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 188
        memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
2132 jermar 189
        memcpy((void *) PA2KA(frame), (void *) (base + i * FRAME_SIZE),
190
            size);
1426 jermar 191
 
192
        if (area->sh_info) {
1546 jermar 193
            frame_reference_add(ADDR2PFN(frame));
2132 jermar 194
            btree_insert(&area->sh_info->pagemap,
195
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
196
                (void *) frame, leaf);
1426 jermar 197
        }
198
 
1424 jermar 199
    }
200
 
1426 jermar 201
    if (area->sh_info)
202
        mutex_unlock(&area->sh_info->lock);
203
 
1424 jermar 204
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1426 jermar 205
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
206
        panic("Could not insert used space.\n");
1424 jermar 207
 
208
    return AS_PF_OK;
209
}
210
 
211
/** Free a frame that is backed by the ELF backend.
212
 *
213
 * The address space area and page tables must be already locked.
214
 *
215
 * @param area Pointer to the address space area.
216
 * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
217
 * @param frame Frame to be released.
218
 *
219
 */
1780 jermar 220
void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
1424 jermar 221
{
1425 jermar 222
    elf_header_t *elf = area->backend_data.elf;
223
    elf_segment_header_t *entry = area->backend_data.segment;
1780 jermar 224
    uintptr_t base;
1424 jermar 225
    index_t i;
226
 
2132 jermar 227
    ASSERT((page >= entry->p_vaddr) &&
228
        (page < entry->p_vaddr + entry->p_memsz));
1424 jermar 229
    i = (page - entry->p_vaddr) >> PAGE_WIDTH;
1780 jermar 230
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
1424 jermar 231
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
232
 
2132 jermar 233
    if (page + PAGE_SIZE <
234
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
1424 jermar 235
        if (entry->p_flags & PF_W) {
236
            /*
2132 jermar 237
             * Free the frame with the copy of writable segment
238
             * data.
1424 jermar 239
             */
1760 palkovsky 240
            frame_free(frame);
2076 jermar 241
#ifdef CONFIG_VIRT_IDX_DCACHE
242
                dcache_flush_frame(page, frame);
243
#endif
1424 jermar 244
        }
245
    } else {
246
        /*
2132 jermar 247
         * The frame is either anonymous memory or the mixed case (i.e.
248
         * lower part is backed by the ELF image and the upper is
249
         * anonymous). In any case, a frame needs to be freed.
1424 jermar 250
         */
1760 palkovsky 251
        frame_free(frame);
2076 jermar 252
#ifdef CONFIG_VIRT_IDX_DCACHE
253
            dcache_flush_frame(page, frame);
254
#endif
1424 jermar 255
    }
256
}
1426 jermar 257
 
258
/** Share ELF image backed address space area.
259
 *
260
 * If the area is writable, then all mapped pages are duplicated in the pagemap.
261
 * Otherwise only portions of the area that are not backed by the ELF image
262
 * are put into the pagemap.
263
 *
264
 * The address space and address space area must be locked prior to the call.
265
 *
266
 * @param area Address space area.
267
 */
268
void elf_share(as_area_t *area)
269
{
270
    elf_segment_header_t *entry = area->backend_data.segment;
271
    link_t *cur;
272
    btree_node_t *leaf, *node;
1780 jermar 273
    uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
1426 jermar 274
 
275
    /*
276
     * Find the node in which to start linear search.
277
     */
278
    if (area->flags & AS_AREA_WRITE) {
2132 jermar 279
        node = list_get_instance(area->used_space.leaf_head.next,
280
            btree_node_t, leaf_link);
1426 jermar 281
    } else {
282
        (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
2132 jermar 283
        node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,
284
            leaf);
1426 jermar 285
        if (!node)
286
            node = leaf;
287
    }
288
 
289
    /*
290
     * Copy used anonymous portions of the area to sh_info's page map.
291
     */
292
    mutex_lock(&area->sh_info->lock);
2132 jermar 293
    for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;
294
        cur = cur->next) {
1426 jermar 295
        int i;
296
 
297
        node = list_get_instance(cur, btree_node_t, leaf_link);
298
 
299
        for (i = 0; i < node->keys; i++) {
1780 jermar 300
            uintptr_t base = node->key[i];
1426 jermar 301
            count_t count = (count_t) node->value[i];
302
            int j;
303
 
304
            /*
305
             * Skip read-only areas of used space that are backed
306
             * by the ELF image.
307
             */
308
            if (!(area->flags & AS_AREA_WRITE))
309
                if (base + count*PAGE_SIZE <= start_anon)
310
                    continue;
311
 
312
            for (j = 0; j < count; j++) {
313
                pte_t *pte;
314
 
315
                /*
2132 jermar 316
                 * Skip read-only pages that are backed by the
317
                 * ELF image.
1426 jermar 318
                 */
319
                if (!(area->flags & AS_AREA_WRITE))
2132 jermar 320
                    if (base + (j + 1) * PAGE_SIZE <=
321
                        start_anon)
1426 jermar 322
                        continue;
323
 
324
                page_table_lock(area->as, false);
2132 jermar 325
                pte = page_mapping_find(area->as,
326
                    base + j * PAGE_SIZE);
327
                ASSERT(pte && PTE_VALID(pte) &&
328
                    PTE_PRESENT(pte));
329
                btree_insert(&area->sh_info->pagemap,
330
                    (base + j * PAGE_SIZE) - area->base,
1426 jermar 331
                    (void *) PTE_GET_FRAME(pte), NULL);
332
                page_table_unlock(area->as, false);
2132 jermar 333
 
334
                pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
335
                frame_reference_add(pfn);
1426 jermar 336
            }
337
 
338
        }
339
    }
340
    mutex_unlock(&area->sh_info->lock);
341
}
1702 cejka 342
 
1757 jermar 343
/** @}
1702 cejka 344
 */
2132 jermar 345