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703 jermar 1
/*
2
 * Copyright (C) 2001-2006 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
 
1248 jermar 29
/**
30
 * @file    as.c
31
 * @brief   Address space related functions.
32
 *
703 jermar 33
 * This file contains address space manipulation functions.
34
 * Roughly speaking, this is a higher-level client of
35
 * Virtual Address Translation (VAT) subsystem.
1248 jermar 36
 *
37
 * Functionality provided by this file allows one to
38
 * create address space and create, resize and share
39
 * address space areas.
40
 *
41
 * @see page.c
42
 *
703 jermar 43
 */
44
 
45
#include <mm/as.h>
756 jermar 46
#include <arch/mm/as.h>
703 jermar 47
#include <mm/page.h>
48
#include <mm/frame.h>
814 palkovsky 49
#include <mm/slab.h>
703 jermar 50
#include <mm/tlb.h>
51
#include <arch/mm/page.h>
52
#include <genarch/mm/page_pt.h>
1108 jermar 53
#include <genarch/mm/page_ht.h>
727 jermar 54
#include <mm/asid.h>
703 jermar 55
#include <arch/mm/asid.h>
56
#include <synch/spinlock.h>
1380 jermar 57
#include <synch/mutex.h>
788 jermar 58
#include <adt/list.h>
1147 jermar 59
#include <adt/btree.h>
1235 jermar 60
#include <proc/task.h>
1288 jermar 61
#include <proc/thread.h>
1235 jermar 62
#include <arch/asm.h>
703 jermar 63
#include <panic.h>
64
#include <debug.h>
1235 jermar 65
#include <print.h>
703 jermar 66
#include <memstr.h>
1070 jermar 67
#include <macros.h>
703 jermar 68
#include <arch.h>
1235 jermar 69
#include <errno.h>
70
#include <config.h>
1387 jermar 71
#include <align.h>
1235 jermar 72
#include <arch/types.h>
73
#include <typedefs.h>
1288 jermar 74
#include <syscall/copy.h>
75
#include <arch/interrupt.h>
703 jermar 76
 
1409 jermar 77
/** This structure contains information associated with the shared address space area. */
78
struct share_info {
79
    mutex_t lock;       /**< This lock must be acquired only when the as_area lock is held. */
80
    count_t refcount;   /**< This structure can be deallocated if refcount drops to 0. */
81
    btree_t pagemap;    /**< B+tree containing complete map of anonymous pages of the shared area. */
82
};
83
 
756 jermar 84
as_operations_t *as_operations = NULL;
703 jermar 85
 
1415 jermar 86
/** This lock protects inactive_as_with_asid_head list. It must be acquired before as_t mutex. */
87
SPINLOCK_INITIALIZE(inactive_as_with_asid_lock);
823 jermar 88
 
89
/**
90
 * This list contains address spaces that are not active on any
91
 * processor and that have valid ASID.
92
 */
93
LIST_INITIALIZE(inactive_as_with_asid_head);
94
 
757 jermar 95
/** Kernel address space. */
96
as_t *AS_KERNEL = NULL;
97
 
1235 jermar 98
static int area_flags_to_page_flags(int aflags);
977 jermar 99
static as_area_t *find_area_and_lock(as_t *as, __address va);
1048 jermar 100
static bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area);
1409 jermar 101
static void sh_info_remove_reference(share_info_t *sh_info);
703 jermar 102
 
756 jermar 103
/** Initialize address space subsystem. */
104
void as_init(void)
105
{
106
    as_arch_init();
789 palkovsky 107
    AS_KERNEL = as_create(FLAG_AS_KERNEL);
1383 decky 108
    if (!AS_KERNEL)
109
        panic("can't create kernel address space\n");
110
 
756 jermar 111
}
112
 
757 jermar 113
/** Create address space.
114
 *
115
 * @param flags Flags that influence way in wich the address space is created.
116
 */
756 jermar 117
as_t *as_create(int flags)
703 jermar 118
{
119
    as_t *as;
120
 
822 palkovsky 121
    as = (as_t *) malloc(sizeof(as_t), 0);
823 jermar 122
    link_initialize(&as->inactive_as_with_asid_link);
1380 jermar 123
    mutex_initialize(&as->lock);
1147 jermar 124
    btree_create(&as->as_area_btree);
822 palkovsky 125
 
126
    if (flags & FLAG_AS_KERNEL)
127
        as->asid = ASID_KERNEL;
128
    else
129
        as->asid = ASID_INVALID;
130
 
1415 jermar 131
    as->cpu_refcount = 0;
822 palkovsky 132
    as->page_table = page_table_create(flags);
703 jermar 133
 
134
    return as;
135
}
136
 
973 palkovsky 137
/** Free Adress space */
138
void as_free(as_t *as)
139
{
1415 jermar 140
    ASSERT(as->cpu_refcount == 0);
973 palkovsky 141
 
142
    /* TODO: free as_areas and other resources held by as */
143
    /* TODO: free page table */
144
    free(as);
145
}
146
 
703 jermar 147
/** Create address space area of common attributes.
148
 *
149
 * The created address space area is added to the target address space.
150
 *
151
 * @param as Target address space.
1239 jermar 152
 * @param flags Flags of the area memory.
1048 jermar 153
 * @param size Size of area.
703 jermar 154
 * @param base Base address of area.
1239 jermar 155
 * @param attrs Attributes of the area.
1409 jermar 156
 * @param backend Address space area backend. NULL if no backend is used.
157
 * @param backend_data NULL or a pointer to an array holding two void *.
703 jermar 158
 *
159
 * @return Address space area on success or NULL on failure.
160
 */
1409 jermar 161
as_area_t *as_area_create(as_t *as, int flags, size_t size, __address base, int attrs,
162
           mem_backend_t *backend, void **backend_data)
703 jermar 163
{
164
    ipl_t ipl;
165
    as_area_t *a;
166
 
167
    if (base % PAGE_SIZE)
1048 jermar 168
        return NULL;
169
 
1233 jermar 170
    if (!size)
171
        return NULL;
172
 
1048 jermar 173
    /* Writeable executable areas are not supported. */
174
    if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
175
        return NULL;
703 jermar 176
 
177
    ipl = interrupts_disable();
1380 jermar 178
    mutex_lock(&as->lock);
703 jermar 179
 
1048 jermar 180
    if (!check_area_conflicts(as, base, size, NULL)) {
1380 jermar 181
        mutex_unlock(&as->lock);
1048 jermar 182
        interrupts_restore(ipl);
183
        return NULL;
184
    }
703 jermar 185
 
822 palkovsky 186
    a = (as_area_t *) malloc(sizeof(as_area_t), 0);
703 jermar 187
 
1380 jermar 188
    mutex_initialize(&a->lock);
822 palkovsky 189
 
1026 jermar 190
    a->flags = flags;
1239 jermar 191
    a->attributes = attrs;
1048 jermar 192
    a->pages = SIZE2FRAMES(size);
822 palkovsky 193
    a->base = base;
1409 jermar 194
    a->sh_info = NULL;
195
    a->backend = backend;
196
    if (backend_data) {
197
        a->backend_data[0] = backend_data[0];
198
        a->backend_data[1] = backend_data[1];
199
    }
1387 jermar 200
    btree_create(&a->used_space);
822 palkovsky 201
 
1147 jermar 202
    btree_insert(&as->as_area_btree, base, (void *) a, NULL);
822 palkovsky 203
 
1380 jermar 204
    mutex_unlock(&as->lock);
703 jermar 205
    interrupts_restore(ipl);
704 jermar 206
 
703 jermar 207
    return a;
208
}
209
 
1235 jermar 210
/** Find address space area and change it.
211
 *
212
 * @param as Address space.
213
 * @param address Virtual address belonging to the area to be changed. Must be page-aligned.
214
 * @param size New size of the virtual memory block starting at address.
215
 * @param flags Flags influencing the remap operation. Currently unused.
216
 *
1306 jermar 217
 * @return Zero on success or a value from @ref errno.h otherwise.
1235 jermar 218
 */
1306 jermar 219
int as_area_resize(as_t *as, __address address, size_t size, int flags)
1235 jermar 220
{
1306 jermar 221
    as_area_t *area;
1235 jermar 222
    ipl_t ipl;
223
    size_t pages;
224
 
225
    ipl = interrupts_disable();
1380 jermar 226
    mutex_lock(&as->lock);
1235 jermar 227
 
228
    /*
229
     * Locate the area.
230
     */
231
    area = find_area_and_lock(as, address);
232
    if (!area) {
1380 jermar 233
        mutex_unlock(&as->lock);
1235 jermar 234
        interrupts_restore(ipl);
1306 jermar 235
        return ENOENT;
1235 jermar 236
    }
237
 
238
    if (area->flags & AS_AREA_DEVICE) {
239
        /*
240
         * Remapping of address space areas associated
241
         * with memory mapped devices is not supported.
242
         */
1380 jermar 243
        mutex_unlock(&area->lock);
244
        mutex_unlock(&as->lock);
1235 jermar 245
        interrupts_restore(ipl);
1306 jermar 246
        return ENOTSUP;
1235 jermar 247
    }
1409 jermar 248
    if (area->sh_info) {
249
        /*
250
         * Remapping of shared address space areas
251
         * is not supported.
252
         */
253
        mutex_unlock(&area->lock);
254
        mutex_unlock(&as->lock);
255
        interrupts_restore(ipl);
256
        return ENOTSUP;
257
    }
1235 jermar 258
 
259
    pages = SIZE2FRAMES((address - area->base) + size);
260
    if (!pages) {
261
        /*
262
         * Zero size address space areas are not allowed.
263
         */
1380 jermar 264
        mutex_unlock(&area->lock);
265
        mutex_unlock(&as->lock);
1235 jermar 266
        interrupts_restore(ipl);
1306 jermar 267
        return EPERM;
1235 jermar 268
    }
269
 
270
    if (pages < area->pages) {
1403 jermar 271
        bool cond;
272
        __address start_free = area->base + pages*PAGE_SIZE;
1235 jermar 273
 
274
        /*
275
         * Shrinking the area.
276
         * No need to check for overlaps.
277
         */
1403 jermar 278
 
279
        /*
280
         * Remove frames belonging to used space starting from
281
         * the highest addresses downwards until an overlap with
282
         * the resized address space area is found. Note that this
283
         * is also the right way to remove part of the used_space
284
         * B+tree leaf list.
285
         */    
286
        for (cond = true; cond;) {
287
            btree_node_t *node;
288
 
289
            ASSERT(!list_empty(&area->used_space.leaf_head));
290
            node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);
291
            if ((cond = (bool) node->keys)) {
292
                __address b = node->key[node->keys - 1];
293
                count_t c = (count_t) node->value[node->keys - 1];
294
                int i = 0;
1235 jermar 295
 
1403 jermar 296
                if (overlaps(b, c*PAGE_SIZE, area->base, pages*PAGE_SIZE)) {
297
 
298
                    if (b + c*PAGE_SIZE <= start_free) {
299
                        /*
300
                         * The whole interval fits completely
301
                         * in the resized address space area.
302
                         */
303
                        break;
304
                    }
305
 
306
                    /*
307
                     * Part of the interval corresponding to b and c
308
                     * overlaps with the resized address space area.
309
                     */
310
 
311
                    cond = false;   /* we are almost done */
312
                    i = (start_free - b) >> PAGE_WIDTH;
313
                    if (!used_space_remove(area, start_free, c - i))
314
                        panic("Could not remove used space.");
315
                } else {
316
                    /*
317
                     * The interval of used space can be completely removed.
318
                     */
319
                    if (!used_space_remove(area, b, c))
320
                        panic("Could not remove used space.\n");
321
                }
322
 
323
                for (; i < c; i++) {
324
                    pte_t *pte;
325
 
326
                    page_table_lock(as, false);
327
                    pte = page_mapping_find(as, b + i*PAGE_SIZE);
328
                    ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
1409 jermar 329
                    if (area->backend && area->backend->backend_frame_free) {
330
                        area->backend->backend_frame_free(area,
331
                            b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
332
                    }
1403 jermar 333
                    page_mapping_remove(as, b + i*PAGE_SIZE);
334
                    page_table_unlock(as, false);
335
                }
1235 jermar 336
            }
337
        }
338
        /*
339
         * Invalidate TLB's.
340
         */
341
        tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
342
        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
343
        tlb_shootdown_finalize();
344
    } else {
345
        /*
346
         * Growing the area.
347
         * Check for overlaps with other address space areas.
348
         */
349
        if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
1380 jermar 350
            mutex_unlock(&area->lock);
351
            mutex_unlock(&as->lock);       
1235 jermar 352
            interrupts_restore(ipl);
1306 jermar 353
            return EADDRNOTAVAIL;
1235 jermar 354
        }
355
    }
356
 
357
    area->pages = pages;
358
 
1380 jermar 359
    mutex_unlock(&area->lock);
360
    mutex_unlock(&as->lock);
1235 jermar 361
    interrupts_restore(ipl);
362
 
1306 jermar 363
    return 0;
1235 jermar 364
}
365
 
1306 jermar 366
/** Destroy address space area.
367
 *
368
 * @param as Address space.
369
 * @param address Address withing the area to be deleted.
370
 *
371
 * @return Zero on success or a value from @ref errno.h on failure.
372
 */
373
int as_area_destroy(as_t *as, __address address)
374
{
375
    as_area_t *area;
376
    __address base;
377
    ipl_t ipl;
1411 jermar 378
    bool cond;
1306 jermar 379
 
380
    ipl = interrupts_disable();
1380 jermar 381
    mutex_lock(&as->lock);
1306 jermar 382
 
383
    area = find_area_and_lock(as, address);
384
    if (!area) {
1380 jermar 385
        mutex_unlock(&as->lock);
1306 jermar 386
        interrupts_restore(ipl);
387
        return ENOENT;
388
    }
389
 
1403 jermar 390
    base = area->base;
391
 
1411 jermar 392
    /*
393
     * Visit only the pages mapped by used_space B+tree.
394
     * Note that we must be very careful when walking the tree
395
     * leaf list and removing used space as the leaf list changes
396
     * unpredictibly after each remove. The solution is to actually
397
     * not walk the tree at all, but to remove items from the head
398
     * of the leaf list until there are some keys left.
399
     */
400
    for (cond = true; cond;) {
401
        btree_node_t *node;
1403 jermar 402
 
1411 jermar 403
        ASSERT(!list_empty(&area->used_space.leaf_head));
404
        node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
405
        if ((cond = (bool) node->keys)) {
406
            __address b = node->key[0];
407
            count_t i;
408
            pte_t *pte;
1403 jermar 409
 
1411 jermar 410
            for (i = 0; i < (count_t) node->value[0]; i++) {
411
                page_table_lock(as, false);
412
                pte = page_mapping_find(as, b + i*PAGE_SIZE);
413
                ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
414
                if (area->backend && area->backend->backend_frame_free) {
415
                    area->backend->backend_frame_free(area,
416
                        b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
1403 jermar 417
                }
1411 jermar 418
                page_mapping_remove(as, b + i*PAGE_SIZE);
419
                page_table_unlock(as, false);
1306 jermar 420
            }
1411 jermar 421
            if (!used_space_remove(area, b, i))
422
                panic("Could not remove used space.\n");
1306 jermar 423
        }
424
    }
1403 jermar 425
    btree_destroy(&area->used_space);
426
 
1306 jermar 427
    /*
428
     * Invalidate TLB's.
429
     */
430
    tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
431
    tlb_invalidate_pages(AS->asid, area->base, area->pages);
432
    tlb_shootdown_finalize();
433
 
1309 jermar 434
    area->attributes |= AS_AREA_ATTR_PARTIAL;
1409 jermar 435
 
436
    if (area->sh_info)
437
        sh_info_remove_reference(area->sh_info);
438
 
1380 jermar 439
    mutex_unlock(&area->lock);
1306 jermar 440
 
441
    /*
442
     * Remove the empty area from address space.
443
     */
444
    btree_remove(&AS->as_area_btree, base, NULL);
445
 
1309 jermar 446
    free(area);
447
 
1380 jermar 448
    mutex_unlock(&AS->lock);
1306 jermar 449
    interrupts_restore(ipl);
450
    return 0;
451
}
452
 
1413 jermar 453
/** Share address space area with another or the same address space.
1235 jermar 454
 *
1413 jermar 455
 * Address space area of anonymous memory is shared with a new address
456
 * space area. If the source address space area has not been shared so
457
 * far, a new sh_info is created and the original mapping is duplicated
458
 * in its pagemap B+tree. The new address space are simply gets the
459
 * sh_info of the source area.
460
 *
1417 jermar 461
 * @param src_as Pointer to source address space.
1239 jermar 462
 * @param src_base Base address of the source address space area.
1417 jermar 463
 * @param acc_size Expected size of the source area.
464
 * @param dst_base Target base address.
465
 * @param dst_flags_mask Destination address space area flags mask.
1235 jermar 466
 *
1306 jermar 467
 * @return Zero on success or ENOENT if there is no such task or
1235 jermar 468
 *     if there is no such address space area,
469
 *     EPERM if there was a problem in accepting the area or
470
 *     ENOMEM if there was a problem in allocating destination
1413 jermar 471
 *     address space area. ENOTSUP is returned if an attempt
472
 *     to share non-anonymous address space area is detected.
1235 jermar 473
 */
1413 jermar 474
int as_area_share(as_t *src_as, __address src_base, size_t acc_size,
1417 jermar 475
          __address dst_base, int dst_flags_mask)
1235 jermar 476
{
477
    ipl_t ipl;
1239 jermar 478
    int src_flags;
479
    size_t src_size;
480
    as_area_t *src_area, *dst_area;
1413 jermar 481
    share_info_t *sh_info;
482
    link_t *cur;
1329 palkovsky 483
 
1235 jermar 484
    ipl = interrupts_disable();
1380 jermar 485
    mutex_lock(&src_as->lock);
1329 palkovsky 486
    src_area = find_area_and_lock(src_as, src_base);
1239 jermar 487
    if (!src_area) {
1238 jermar 488
        /*
489
         * Could not find the source address space area.
490
         */
1380 jermar 491
        mutex_unlock(&src_as->lock);
1238 jermar 492
        interrupts_restore(ipl);
493
        return ENOENT;
494
    }
1413 jermar 495
 
496
    if (!src_area->backend || src_area->backend != &anon_backend) {
497
        /*
498
         * As of now, only anonymous address space areas can be shared.
499
         */
500
        mutex_unlock(&src_area->lock);
501
        mutex_unlock(&src_as->lock);
502
        interrupts_restore(ipl);
503
        return ENOTSUP;
504
    }
505
 
1239 jermar 506
    src_size = src_area->pages * PAGE_SIZE;
507
    src_flags = src_area->flags;
1413 jermar 508
 
1329 palkovsky 509
    if (src_size != acc_size) {
1413 jermar 510
        mutex_unlock(&src_area->lock);
511
        mutex_unlock(&src_as->lock);
1235 jermar 512
        interrupts_restore(ipl);
513
        return EPERM;
514
    }
1413 jermar 515
 
1235 jermar 516
    /*
1413 jermar 517
     * Now we are committed to sharing the area.
518
     * First prepare the area for sharing.
519
     * Then it will be safe to unlock it.
520
     */
521
    sh_info = src_area->sh_info;
522
    if (!sh_info) {
523
        sh_info = (share_info_t *) malloc(sizeof(share_info_t), 0);
524
        mutex_initialize(&sh_info->lock);
525
        sh_info->refcount = 2;
526
        btree_create(&sh_info->pagemap);
527
        src_area->sh_info = sh_info;
528
    } else {
529
        mutex_lock(&sh_info->lock);
530
        sh_info->refcount++;
531
        mutex_unlock(&sh_info->lock);
532
    }
533
 
534
    /*
535
     * Copy used portions of the area to sh_info's page map.
536
     */
537
    mutex_lock(&sh_info->lock);
538
    for (cur = src_area->used_space.leaf_head.next; cur != &src_area->used_space.leaf_head; cur = cur->next) {
539
        btree_node_t *node;
540
        int i;
541
 
542
        node = list_get_instance(cur, btree_node_t, leaf_link);
543
        for (i = 0; i < node->keys; i++) {
544
            __address base = node->key[i];
545
            count_t count = (count_t) node->value[i];
546
            int j;
547
 
548
            for (j = 0; j < count; j++) {
549
                pte_t *pte;
550
 
551
                page_table_lock(src_as, false);
552
                pte = page_mapping_find(src_as, base + j*PAGE_SIZE);
553
                ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
554
                btree_insert(&sh_info->pagemap, (base + j*PAGE_SIZE) - src_area->base,
555
                    (void *) PTE_GET_FRAME(pte), NULL);
556
                page_table_unlock(src_as, false);
557
            }
558
 
559
        }
560
    }
561
    mutex_unlock(&sh_info->lock);
562
 
563
    mutex_unlock(&src_area->lock);
564
    mutex_unlock(&src_as->lock);
565
 
566
    /*
1239 jermar 567
     * Create copy of the source address space area.
568
     * The destination area is created with AS_AREA_ATTR_PARTIAL
569
     * attribute set which prevents race condition with
570
     * preliminary as_page_fault() calls.
1417 jermar 571
     * The flags of the source area are masked against dst_flags_mask
572
     * to support sharing in less privileged mode.
1235 jermar 573
     */
1417 jermar 574
    dst_area = as_area_create(AS, src_flags & dst_flags_mask, src_size, dst_base,
575
                  AS_AREA_ATTR_PARTIAL, &anon_backend, NULL);
1239 jermar 576
    if (!dst_area) {
1235 jermar 577
        /*
578
         * Destination address space area could not be created.
579
         */
1413 jermar 580
        sh_info_remove_reference(sh_info);
581
 
1235 jermar 582
        interrupts_restore(ipl);
583
        return ENOMEM;
584
    }
585
 
586
    /*
1239 jermar 587
     * Now the destination address space area has been
588
     * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
1413 jermar 589
     * attribute and set the sh_info.
1239 jermar 590
     */
1380 jermar 591
    mutex_lock(&dst_area->lock);
1239 jermar 592
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
1413 jermar 593
    dst_area->sh_info = sh_info;
1380 jermar 594
    mutex_unlock(&dst_area->lock);
1235 jermar 595
 
596
    interrupts_restore(ipl);
597
 
598
    return 0;
599
}
600
 
754 jermar 601
/** Initialize mapping for one page of address space.
703 jermar 602
 *
754 jermar 603
 * This functions maps 'page' to 'frame' according
604
 * to attributes of the address space area to
605
 * wich 'page' belongs.
703 jermar 606
 *
840 jermar 607
 * @param as Target address space.
754 jermar 608
 * @param page Virtual page within the area.
609
 * @param frame Physical frame to which page will be mapped.
703 jermar 610
 */
754 jermar 611
void as_set_mapping(as_t *as, __address page, __address frame)
703 jermar 612
{
977 jermar 613
    as_area_t *area;
703 jermar 614
    ipl_t ipl;
615
 
616
    ipl = interrupts_disable();
1044 jermar 617
    page_table_lock(as, true);
703 jermar 618
 
977 jermar 619
    area = find_area_and_lock(as, page);
754 jermar 620
    if (!area) {
1403 jermar 621
        panic("Page not part of any as_area.\n");
754 jermar 622
    }
623
 
1409 jermar 624
    ASSERT(!area->backend);
625
 
626
    page_mapping_insert(as, page, frame, as_area_get_flags(area));
1403 jermar 627
    if (!used_space_insert(area, page, 1))
628
        panic("Could not insert used space.\n");
754 jermar 629
 
1380 jermar 630
    mutex_unlock(&area->lock);
1044 jermar 631
    page_table_unlock(as, true);
703 jermar 632
    interrupts_restore(ipl);
633
}
634
 
1423 jermar 635
/** Check access mode for address space area.
636
 *
637
 * The address space area must be locked prior to this call.
638
 *
639
 * @param area Address space area.
640
 * @param access Access mode.
641
 *
642
 * @return False if access violates area's permissions, true otherwise.
643
 */
644
bool as_area_check_access(as_area_t *area, pf_access_t access)
645
{
646
    int flagmap[] = {
647
        [PF_ACCESS_READ] = AS_AREA_READ,
648
        [PF_ACCESS_WRITE] = AS_AREA_WRITE,
649
        [PF_ACCESS_EXEC] = AS_AREA_EXEC
650
    };
651
 
652
    if (!(area->flags & flagmap[access]))
653
        return false;
654
 
655
    return true;
656
}
657
 
703 jermar 658
/** Handle page fault within the current address space.
659
 *
1409 jermar 660
 * This is the high-level page fault handler. It decides
661
 * whether the page fault can be resolved by any backend
662
 * and if so, it invokes the backend to resolve the page
663
 * fault.
664
 *
703 jermar 665
 * Interrupts are assumed disabled.
666
 *
667
 * @param page Faulting page.
1411 jermar 668
 * @param access Access mode that caused the fault (i.e. read/write/exec).
1288 jermar 669
 * @param istate Pointer to interrupted state.
703 jermar 670
 *
1409 jermar 671
 * @return AS_PF_FAULT on page fault, AS_PF_OK on success or AS_PF_DEFER if the
672
 *     fault was caused by copy_to_uspace() or copy_from_uspace().
703 jermar 673
 */
1411 jermar 674
int as_page_fault(__address page, pf_access_t access, istate_t *istate)
703 jermar 675
{
1044 jermar 676
    pte_t *pte;
977 jermar 677
    as_area_t *area;
703 jermar 678
 
1380 jermar 679
    if (!THREAD)
1409 jermar 680
        return AS_PF_FAULT;
1380 jermar 681
 
703 jermar 682
    ASSERT(AS);
1044 jermar 683
 
1380 jermar 684
    mutex_lock(&AS->lock);
977 jermar 685
    area = find_area_and_lock(AS, page);   
703 jermar 686
    if (!area) {
687
        /*
688
         * No area contained mapping for 'page'.
689
         * Signal page fault to low-level handler.
690
         */
1380 jermar 691
        mutex_unlock(&AS->lock);
1288 jermar 692
        goto page_fault;
703 jermar 693
    }
694
 
1239 jermar 695
    if (area->attributes & AS_AREA_ATTR_PARTIAL) {
696
        /*
697
         * The address space area is not fully initialized.
698
         * Avoid possible race by returning error.
699
         */
1380 jermar 700
        mutex_unlock(&area->lock);
701
        mutex_unlock(&AS->lock);
1288 jermar 702
        goto page_fault;       
1239 jermar 703
    }
704
 
1409 jermar 705
    if (!area->backend || !area->backend->backend_page_fault) {
706
        /*
707
         * The address space area is not backed by any backend
708
         * or the backend cannot handle page faults.
709
         */
710
        mutex_unlock(&area->lock);
711
        mutex_unlock(&AS->lock);
712
        goto page_fault;       
713
    }
1179 jermar 714
 
1044 jermar 715
    page_table_lock(AS, false);
716
 
703 jermar 717
    /*
1044 jermar 718
     * To avoid race condition between two page faults
719
     * on the same address, we need to make sure
720
     * the mapping has not been already inserted.
721
     */
722
    if ((pte = page_mapping_find(AS, page))) {
723
        if (PTE_PRESENT(pte)) {
1423 jermar 724
            if (((access == PF_ACCESS_READ) && PTE_READABLE(pte)) ||
725
                (access == PF_ACCESS_WRITE && PTE_WRITABLE(pte)) ||
726
                (access == PF_ACCESS_EXEC && PTE_EXECUTABLE(pte))) {
727
                page_table_unlock(AS, false);
728
                mutex_unlock(&area->lock);
729
                mutex_unlock(&AS->lock);
730
                return AS_PF_OK;
731
            }
1044 jermar 732
        }
733
    }
1409 jermar 734
 
1044 jermar 735
    /*
1409 jermar 736
     * Resort to the backend page fault handler.
703 jermar 737
     */
1411 jermar 738
    if (area->backend->backend_page_fault(area, page, access) != AS_PF_OK) {
1409 jermar 739
        page_table_unlock(AS, false);
740
        mutex_unlock(&area->lock);
741
        mutex_unlock(&AS->lock);
742
        goto page_fault;
743
    }
703 jermar 744
 
1044 jermar 745
    page_table_unlock(AS, false);
1380 jermar 746
    mutex_unlock(&area->lock);
747
    mutex_unlock(&AS->lock);
1288 jermar 748
    return AS_PF_OK;
749
 
750
page_fault:
751
    if (THREAD->in_copy_from_uspace) {
752
        THREAD->in_copy_from_uspace = false;
753
        istate_set_retaddr(istate, (__address) &memcpy_from_uspace_failover_address);
754
    } else if (THREAD->in_copy_to_uspace) {
755
        THREAD->in_copy_to_uspace = false;
756
        istate_set_retaddr(istate, (__address) &memcpy_to_uspace_failover_address);
757
    } else {
758
        return AS_PF_FAULT;
759
    }
760
 
761
    return AS_PF_DEFER;
703 jermar 762
}
763
 
823 jermar 764
/** Switch address spaces.
703 jermar 765
 *
1380 jermar 766
 * Note that this function cannot sleep as it is essentially a part of
1415 jermar 767
 * scheduling. Sleeping here would lead to deadlock on wakeup.
1380 jermar 768
 *
823 jermar 769
 * @param old Old address space or NULL.
770
 * @param new New address space.
703 jermar 771
 */
823 jermar 772
void as_switch(as_t *old, as_t *new)
703 jermar 773
{
774
    ipl_t ipl;
823 jermar 775
    bool needs_asid = false;
703 jermar 776
 
777
    ipl = interrupts_disable();
1415 jermar 778
    spinlock_lock(&inactive_as_with_asid_lock);
703 jermar 779
 
780
    /*
823 jermar 781
     * First, take care of the old address space.
782
     */
783
    if (old) {
1380 jermar 784
        mutex_lock_active(&old->lock);
1415 jermar 785
        ASSERT(old->cpu_refcount);
786
        if((--old->cpu_refcount == 0) && (old != AS_KERNEL)) {
823 jermar 787
            /*
788
             * The old address space is no longer active on
789
             * any processor. It can be appended to the
790
             * list of inactive address spaces with assigned
791
             * ASID.
792
             */
793
             ASSERT(old->asid != ASID_INVALID);
794
             list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
795
        }
1380 jermar 796
        mutex_unlock(&old->lock);
823 jermar 797
    }
798
 
799
    /*
800
     * Second, prepare the new address space.
801
     */
1380 jermar 802
    mutex_lock_active(&new->lock);
1415 jermar 803
    if ((new->cpu_refcount++ == 0) && (new != AS_KERNEL)) {
823 jermar 804
        if (new->asid != ASID_INVALID)
805
            list_remove(&new->inactive_as_with_asid_link);
806
        else
807
            needs_asid = true;  /* defer call to asid_get() until new->lock is released */
808
    }
809
    SET_PTL0_ADDRESS(new->page_table);
1380 jermar 810
    mutex_unlock(&new->lock);
823 jermar 811
 
812
    if (needs_asid) {
813
        /*
814
         * Allocation of new ASID was deferred
815
         * until now in order to avoid deadlock.
816
         */
817
        asid_t asid;
818
 
819
        asid = asid_get();
1380 jermar 820
        mutex_lock_active(&new->lock);
823 jermar 821
        new->asid = asid;
1380 jermar 822
        mutex_unlock(&new->lock);
823 jermar 823
    }
1415 jermar 824
    spinlock_unlock(&inactive_as_with_asid_lock);
823 jermar 825
    interrupts_restore(ipl);
826
 
827
    /*
703 jermar 828
     * Perform architecture-specific steps.
727 jermar 829
     * (e.g. write ASID to hardware register etc.)
703 jermar 830
     */
823 jermar 831
    as_install_arch(new);
703 jermar 832
 
823 jermar 833
    AS = new;
703 jermar 834
}
754 jermar 835
 
1235 jermar 836
/** Convert address space area flags to page flags.
754 jermar 837
 *
1235 jermar 838
 * @param aflags Flags of some address space area.
754 jermar 839
 *
1235 jermar 840
 * @return Flags to be passed to page_mapping_insert().
754 jermar 841
 */
1235 jermar 842
int area_flags_to_page_flags(int aflags)
754 jermar 843
{
844
    int flags;
845
 
1178 jermar 846
    flags = PAGE_USER | PAGE_PRESENT;
754 jermar 847
 
1235 jermar 848
    if (aflags & AS_AREA_READ)
1026 jermar 849
        flags |= PAGE_READ;
850
 
1235 jermar 851
    if (aflags & AS_AREA_WRITE)
1026 jermar 852
        flags |= PAGE_WRITE;
853
 
1235 jermar 854
    if (aflags & AS_AREA_EXEC)
1026 jermar 855
        flags |= PAGE_EXEC;
856
 
1235 jermar 857
    if (!(aflags & AS_AREA_DEVICE))
1178 jermar 858
        flags |= PAGE_CACHEABLE;
859
 
754 jermar 860
    return flags;
861
}
756 jermar 862
 
1235 jermar 863
/** Compute flags for virtual address translation subsytem.
864
 *
865
 * The address space area must be locked.
866
 * Interrupts must be disabled.
867
 *
868
 * @param a Address space area.
869
 *
870
 * @return Flags to be used in page_mapping_insert().
871
 */
1409 jermar 872
int as_area_get_flags(as_area_t *a)
1235 jermar 873
{
874
    return area_flags_to_page_flags(a->flags);
875
}
876
 
756 jermar 877
/** Create page table.
878
 *
879
 * Depending on architecture, create either address space
880
 * private or global page table.
881
 *
882
 * @param flags Flags saying whether the page table is for kernel address space.
883
 *
884
 * @return First entry of the page table.
885
 */
886
pte_t *page_table_create(int flags)
887
{
888
        ASSERT(as_operations);
889
        ASSERT(as_operations->page_table_create);
890
 
891
        return as_operations->page_table_create(flags);
892
}
977 jermar 893
 
1044 jermar 894
/** Lock page table.
895
 *
896
 * This function should be called before any page_mapping_insert(),
897
 * page_mapping_remove() and page_mapping_find().
898
 *
899
 * Locking order is such that address space areas must be locked
900
 * prior to this call. Address space can be locked prior to this
901
 * call in which case the lock argument is false.
902
 *
903
 * @param as Address space.
1248 jermar 904
 * @param lock If false, do not attempt to lock as->lock.
1044 jermar 905
 */
906
void page_table_lock(as_t *as, bool lock)
907
{
908
    ASSERT(as_operations);
909
    ASSERT(as_operations->page_table_lock);
910
 
911
    as_operations->page_table_lock(as, lock);
912
}
913
 
914
/** Unlock page table.
915
 *
916
 * @param as Address space.
1248 jermar 917
 * @param unlock If false, do not attempt to unlock as->lock.
1044 jermar 918
 */
919
void page_table_unlock(as_t *as, bool unlock)
920
{
921
    ASSERT(as_operations);
922
    ASSERT(as_operations->page_table_unlock);
923
 
924
    as_operations->page_table_unlock(as, unlock);
925
}
926
 
977 jermar 927
 
928
/** Find address space area and lock it.
929
 *
930
 * The address space must be locked and interrupts must be disabled.
931
 *
932
 * @param as Address space.
933
 * @param va Virtual address.
934
 *
935
 * @return Locked address space area containing va on success or NULL on failure.
936
 */
937
as_area_t *find_area_and_lock(as_t *as, __address va)
938
{
939
    as_area_t *a;
1147 jermar 940
    btree_node_t *leaf, *lnode;
941
    int i;
977 jermar 942
 
1147 jermar 943
    a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf);
944
    if (a) {
945
        /* va is the base address of an address space area */
1380 jermar 946
        mutex_lock(&a->lock);
1147 jermar 947
        return a;
948
    }
949
 
950
    /*
1150 jermar 951
     * Search the leaf node and the righmost record of its left neighbour
1147 jermar 952
     * to find out whether this is a miss or va belongs to an address
953
     * space area found there.
954
     */
955
 
956
    /* First, search the leaf node itself. */
957
    for (i = 0; i < leaf->keys; i++) {
958
        a = (as_area_t *) leaf->value[i];
1380 jermar 959
        mutex_lock(&a->lock);
1147 jermar 960
        if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) {
961
            return a;
962
        }
1380 jermar 963
        mutex_unlock(&a->lock);
1147 jermar 964
    }
977 jermar 965
 
1147 jermar 966
    /*
1150 jermar 967
     * Second, locate the left neighbour and test its last record.
1148 jermar 968
     * Because of its position in the B+tree, it must have base < va.
1147 jermar 969
     */
1150 jermar 970
    if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 971
        a = (as_area_t *) lnode->value[lnode->keys - 1];
1380 jermar 972
        mutex_lock(&a->lock);
1147 jermar 973
        if (va < a->base + a->pages * PAGE_SIZE) {
1048 jermar 974
            return a;
1147 jermar 975
        }
1380 jermar 976
        mutex_unlock(&a->lock);
977 jermar 977
    }
978
 
979
    return NULL;
980
}
1048 jermar 981
 
982
/** Check area conflicts with other areas.
983
 *
984
 * The address space must be locked and interrupts must be disabled.
985
 *
986
 * @param as Address space.
987
 * @param va Starting virtual address of the area being tested.
988
 * @param size Size of the area being tested.
989
 * @param avoid_area Do not touch this area.
990
 *
991
 * @return True if there is no conflict, false otherwise.
992
 */
993
bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area)
994
{
995
    as_area_t *a;
1147 jermar 996
    btree_node_t *leaf, *node;
997
    int i;
1048 jermar 998
 
1070 jermar 999
    /*
1000
     * We don't want any area to have conflicts with NULL page.
1001
     */
1002
    if (overlaps(va, size, NULL, PAGE_SIZE))
1003
        return false;
1004
 
1147 jermar 1005
    /*
1006
     * The leaf node is found in O(log n), where n is proportional to
1007
     * the number of address space areas belonging to as.
1008
     * The check for conflicts is then attempted on the rightmost
1150 jermar 1009
     * record in the left neighbour, the leftmost record in the right
1010
     * neighbour and all records in the leaf node itself.
1147 jermar 1011
     */
1048 jermar 1012
 
1147 jermar 1013
    if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) {
1014
        if (a != avoid_area)
1015
            return false;
1016
    }
1017
 
1018
    /* First, check the two border cases. */
1150 jermar 1019
    if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 1020
        a = (as_area_t *) node->value[node->keys - 1];
1380 jermar 1021
        mutex_lock(&a->lock);
1147 jermar 1022
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 1023
            mutex_unlock(&a->lock);
1147 jermar 1024
            return false;
1025
        }
1380 jermar 1026
        mutex_unlock(&a->lock);
1147 jermar 1027
    }
1150 jermar 1028
    if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 1029
        a = (as_area_t *) node->value[0];
1380 jermar 1030
        mutex_lock(&a->lock);
1147 jermar 1031
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 1032
            mutex_unlock(&a->lock);
1147 jermar 1033
            return false;
1034
        }
1380 jermar 1035
        mutex_unlock(&a->lock);
1147 jermar 1036
    }
1037
 
1038
    /* Second, check the leaf node. */
1039
    for (i = 0; i < leaf->keys; i++) {
1040
        a = (as_area_t *) leaf->value[i];
1041
 
1048 jermar 1042
        if (a == avoid_area)
1043
            continue;
1147 jermar 1044
 
1380 jermar 1045
        mutex_lock(&a->lock);
1147 jermar 1046
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 1047
            mutex_unlock(&a->lock);
1147 jermar 1048
            return false;
1049
        }
1380 jermar 1050
        mutex_unlock(&a->lock);
1048 jermar 1051
    }
1052
 
1070 jermar 1053
    /*
1054
     * So far, the area does not conflict with other areas.
1055
     * Check if it doesn't conflict with kernel address space.
1056
     */  
1057
    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
1058
        return !overlaps(va, size,
1059
            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START);
1060
    }
1061
 
1048 jermar 1062
    return true;
1063
}
1235 jermar 1064
 
1380 jermar 1065
/** Return size of the address space area with given base.  */
1329 palkovsky 1066
size_t as_get_size(__address base)
1067
{
1068
    ipl_t ipl;
1069
    as_area_t *src_area;
1070
    size_t size;
1071
 
1072
    ipl = interrupts_disable();
1073
    src_area = find_area_and_lock(AS, base);
1074
    if (src_area){
1075
        size = src_area->pages * PAGE_SIZE;
1380 jermar 1076
        mutex_unlock(&src_area->lock);
1329 palkovsky 1077
    } else {
1078
        size = 0;
1079
    }
1080
    interrupts_restore(ipl);
1081
    return size;
1082
}
1083
 
1387 jermar 1084
/** Mark portion of address space area as used.
1085
 *
1086
 * The address space area must be already locked.
1087
 *
1088
 * @param a Address space area.
1089
 * @param page First page to be marked.
1090
 * @param count Number of page to be marked.
1091
 *
1092
 * @return 0 on failure and 1 on success.
1093
 */
1094
int used_space_insert(as_area_t *a, __address page, count_t count)
1095
{
1096
    btree_node_t *leaf, *node;
1097
    count_t pages;
1098
    int i;
1099
 
1100
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1101
    ASSERT(count);
1102
 
1103
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1104
    if (pages) {
1105
        /*
1106
         * We hit the beginning of some used space.
1107
         */
1108
        return 0;
1109
    }
1110
 
1111
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1112
    if (node) {
1113
        __address left_pg = node->key[node->keys - 1], right_pg = leaf->key[0];
1114
        count_t left_cnt = (count_t) node->value[node->keys - 1], right_cnt = (count_t) leaf->value[0];
1115
 
1116
        /*
1117
         * Examine the possibility that the interval fits
1118
         * somewhere between the rightmost interval of
1119
         * the left neigbour and the first interval of the leaf.
1120
         */
1121
 
1122
        if (page >= right_pg) {
1123
            /* Do nothing. */
1124
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1125
            /* The interval intersects with the left interval. */
1126
            return 0;
1127
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1128
            /* The interval intersects with the right interval. */
1129
            return 0;          
1130
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1131
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1132
            node->value[node->keys - 1] += count + right_cnt;
1387 jermar 1133
            btree_remove(&a->used_space, right_pg, leaf);
1134
            return 1;
1135
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1136
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1137
            node->value[node->keys - 1] += count;
1387 jermar 1138
            return 1;
1139
        } else if (page + count*PAGE_SIZE == right_pg) {
1140
            /*
1141
             * The interval can be addded by simply moving base of the right
1142
             * interval down and increasing its size accordingly.
1143
             */
1403 jermar 1144
            leaf->value[0] += count;
1387 jermar 1145
            leaf->key[0] = page;
1146
            return 1;
1147
        } else {
1148
            /*
1149
             * The interval is between both neigbouring intervals,
1150
             * but cannot be merged with any of them.
1151
             */
1152
            btree_insert(&a->used_space, page, (void *) count, leaf);
1153
            return 1;
1154
        }
1155
    } else if (page < leaf->key[0]) {
1156
        __address right_pg = leaf->key[0];
1157
        count_t right_cnt = (count_t) leaf->value[0];
1158
 
1159
        /*
1160
         * Investigate the border case in which the left neighbour does not
1161
         * exist but the interval fits from the left.
1162
         */
1163
 
1164
        if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1165
            /* The interval intersects with the right interval. */
1166
            return 0;
1167
        } else if (page + count*PAGE_SIZE == right_pg) {
1168
            /*
1169
             * The interval can be added by moving the base of the right interval down
1170
             * and increasing its size accordingly.
1171
             */
1172
            leaf->key[0] = page;
1403 jermar 1173
            leaf->value[0] += count;
1387 jermar 1174
            return 1;
1175
        } else {
1176
            /*
1177
             * The interval doesn't adjoin with the right interval.
1178
             * It must be added individually.
1179
             */
1180
            btree_insert(&a->used_space, page, (void *) count, leaf);
1181
            return 1;
1182
        }
1183
    }
1184
 
1185
    node = btree_leaf_node_right_neighbour(&a->used_space, leaf);
1186
    if (node) {
1187
        __address left_pg = leaf->key[leaf->keys - 1], right_pg = node->key[0];
1188
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1], right_cnt = (count_t) node->value[0];
1189
 
1190
        /*
1191
         * Examine the possibility that the interval fits
1192
         * somewhere between the leftmost interval of
1193
         * the right neigbour and the last interval of the leaf.
1194
         */
1195
 
1196
        if (page < left_pg) {
1197
            /* Do nothing. */
1198
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1199
            /* The interval intersects with the left interval. */
1200
            return 0;
1201
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1202
            /* The interval intersects with the right interval. */
1203
            return 0;          
1204
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1205
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1206
            leaf->value[leaf->keys - 1] += count + right_cnt;
1387 jermar 1207
            btree_remove(&a->used_space, right_pg, node);
1208
            return 1;
1209
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1210
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1211
            leaf->value[leaf->keys - 1] +=  count;
1387 jermar 1212
            return 1;
1213
        } else if (page + count*PAGE_SIZE == right_pg) {
1214
            /*
1215
             * The interval can be addded by simply moving base of the right
1216
             * interval down and increasing its size accordingly.
1217
             */
1403 jermar 1218
            node->value[0] += count;
1387 jermar 1219
            node->key[0] = page;
1220
            return 1;
1221
        } else {
1222
            /*
1223
             * The interval is between both neigbouring intervals,
1224
             * but cannot be merged with any of them.
1225
             */
1226
            btree_insert(&a->used_space, page, (void *) count, leaf);
1227
            return 1;
1228
        }
1229
    } else if (page >= leaf->key[leaf->keys - 1]) {
1230
        __address left_pg = leaf->key[leaf->keys - 1];
1231
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1232
 
1233
        /*
1234
         * Investigate the border case in which the right neighbour does not
1235
         * exist but the interval fits from the right.
1236
         */
1237
 
1238
        if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1403 jermar 1239
            /* The interval intersects with the left interval. */
1387 jermar 1240
            return 0;
1241
        } else if (left_pg + left_cnt*PAGE_SIZE == page) {
1242
            /* The interval can be added by growing the left interval. */
1403 jermar 1243
            leaf->value[leaf->keys - 1] += count;
1387 jermar 1244
            return 1;
1245
        } else {
1246
            /*
1247
             * The interval doesn't adjoin with the left interval.
1248
             * It must be added individually.
1249
             */
1250
            btree_insert(&a->used_space, page, (void *) count, leaf);
1251
            return 1;
1252
        }
1253
    }
1254
 
1255
    /*
1256
     * Note that if the algorithm made it thus far, the interval can fit only
1257
     * between two other intervals of the leaf. The two border cases were already
1258
     * resolved.
1259
     */
1260
    for (i = 1; i < leaf->keys; i++) {
1261
        if (page < leaf->key[i]) {
1262
            __address left_pg = leaf->key[i - 1], right_pg = leaf->key[i];
1263
            count_t left_cnt = (count_t) leaf->value[i - 1], right_cnt = (count_t) leaf->value[i];
1264
 
1265
            /*
1266
             * The interval fits between left_pg and right_pg.
1267
             */
1268
 
1269
            if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1270
                /* The interval intersects with the left interval. */
1271
                return 0;
1272
            } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1273
                /* The interval intersects with the right interval. */
1274
                return 0;          
1275
            } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1276
                /* The interval can be added by merging the two already present intervals. */
1403 jermar 1277
                leaf->value[i - 1] += count + right_cnt;
1387 jermar 1278
                btree_remove(&a->used_space, right_pg, leaf);
1279
                return 1;
1280
            } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1281
                /* The interval can be added by simply growing the left interval. */
1403 jermar 1282
                leaf->value[i - 1] += count;
1387 jermar 1283
                return 1;
1284
            } else if (page + count*PAGE_SIZE == right_pg) {
1285
                /*
1286
                     * The interval can be addded by simply moving base of the right
1287
                 * interval down and increasing its size accordingly.
1288
                 */
1403 jermar 1289
                leaf->value[i] += count;
1387 jermar 1290
                leaf->key[i] = page;
1291
                return 1;
1292
            } else {
1293
                /*
1294
                 * The interval is between both neigbouring intervals,
1295
                 * but cannot be merged with any of them.
1296
                 */
1297
                btree_insert(&a->used_space, page, (void *) count, leaf);
1298
                return 1;
1299
            }
1300
        }
1301
    }
1302
 
1303
    panic("Inconsistency detected while adding %d pages of used space at %P.\n", count, page);
1304
}
1305
 
1306
/** Mark portion of address space area as unused.
1307
 *
1308
 * The address space area must be already locked.
1309
 *
1310
 * @param a Address space area.
1311
 * @param page First page to be marked.
1312
 * @param count Number of page to be marked.
1313
 *
1314
 * @return 0 on failure and 1 on success.
1315
 */
1316
int used_space_remove(as_area_t *a, __address page, count_t count)
1317
{
1318
    btree_node_t *leaf, *node;
1319
    count_t pages;
1320
    int i;
1321
 
1322
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1323
    ASSERT(count);
1324
 
1325
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1326
    if (pages) {
1327
        /*
1328
         * We are lucky, page is the beginning of some interval.
1329
         */
1330
        if (count > pages) {
1331
            return 0;
1332
        } else if (count == pages) {
1333
            btree_remove(&a->used_space, page, leaf);
1403 jermar 1334
            return 1;
1387 jermar 1335
        } else {
1336
            /*
1337
             * Find the respective interval.
1338
             * Decrease its size and relocate its start address.
1339
             */
1340
            for (i = 0; i < leaf->keys; i++) {
1341
                if (leaf->key[i] == page) {
1342
                    leaf->key[i] += count*PAGE_SIZE;
1403 jermar 1343
                    leaf->value[i] -= count;
1387 jermar 1344
                    return 1;
1345
                }
1346
            }
1347
            goto error;
1348
        }
1349
    }
1350
 
1351
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1352
    if (node && page < leaf->key[0]) {
1353
        __address left_pg = node->key[node->keys - 1];
1354
        count_t left_cnt = (count_t) node->value[node->keys - 1];
1355
 
1356
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1357
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1358
                /*
1359
                 * The interval is contained in the rightmost interval
1360
                 * of the left neighbour and can be removed by
1361
                 * updating the size of the bigger interval.
1362
                 */
1403 jermar 1363
                node->value[node->keys - 1] -= count;
1387 jermar 1364
                return 1;
1365
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1366
                count_t new_cnt;
1387 jermar 1367
 
1368
                /*
1369
                 * The interval is contained in the rightmost interval
1370
                 * of the left neighbour but its removal requires
1371
                 * both updating the size of the original interval and
1372
                 * also inserting a new interval.
1373
                 */
1403 jermar 1374
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1375
                node->value[node->keys - 1] -= count + new_cnt;
1387 jermar 1376
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1377
                return 1;
1378
            }
1379
        }
1380
        return 0;
1381
    } else if (page < leaf->key[0]) {
1382
        return 0;
1383
    }
1384
 
1385
    if (page > leaf->key[leaf->keys - 1]) {
1386
        __address left_pg = leaf->key[leaf->keys - 1];
1387
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1388
 
1389
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1390
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1391
                /*
1392
                 * The interval is contained in the rightmost interval
1393
                 * of the leaf and can be removed by updating the size
1394
                 * of the bigger interval.
1395
                 */
1403 jermar 1396
                leaf->value[leaf->keys - 1] -= count;
1387 jermar 1397
                return 1;
1398
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1399
                count_t new_cnt;
1387 jermar 1400
 
1401
                /*
1402
                 * The interval is contained in the rightmost interval
1403
                 * of the leaf but its removal requires both updating
1404
                 * the size of the original interval and
1405
                 * also inserting a new interval.
1406
                 */
1403 jermar 1407
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1408
                leaf->value[leaf->keys - 1] -= count + new_cnt;
1387 jermar 1409
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1410
                return 1;
1411
            }
1412
        }
1413
        return 0;
1414
    }  
1415
 
1416
    /*
1417
     * The border cases have been already resolved.
1418
     * Now the interval can be only between intervals of the leaf.
1419
     */
1420
    for (i = 1; i < leaf->keys - 1; i++) {
1421
        if (page < leaf->key[i]) {
1422
            __address left_pg = leaf->key[i - 1];
1423
            count_t left_cnt = (count_t) leaf->value[i - 1];
1424
 
1425
            /*
1426
             * Now the interval is between intervals corresponding to (i - 1) and i.
1427
             */
1428
            if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1429
                if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1430
                    /*
1431
                    * The interval is contained in the interval (i - 1)
1432
                     * of the leaf and can be removed by updating the size
1433
                     * of the bigger interval.
1434
                     */
1403 jermar 1435
                    leaf->value[i - 1] -= count;
1387 jermar 1436
                    return 1;
1437
                } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1438
                    count_t new_cnt;
1387 jermar 1439
 
1440
                    /*
1441
                     * The interval is contained in the interval (i - 1)
1442
                     * of the leaf but its removal requires both updating
1443
                     * the size of the original interval and
1444
                     * also inserting a new interval.
1445
                     */
1403 jermar 1446
                    new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1447
                    leaf->value[i - 1] -= count + new_cnt;
1387 jermar 1448
                    btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1449
                    return 1;
1450
                }
1451
            }
1452
            return 0;
1453
        }
1454
    }
1455
 
1456
error:
1457
    panic("Inconsistency detected while removing %d pages of used space from %P.\n", count, page);
1458
}
1459
 
1409 jermar 1460
/** Remove reference to address space area share info.
1461
 *
1462
 * If the reference count drops to 0, the sh_info is deallocated.
1463
 *
1464
 * @param sh_info Pointer to address space area share info.
1465
 */
1466
void sh_info_remove_reference(share_info_t *sh_info)
1467
{
1468
    bool dealloc = false;
1469
 
1470
    mutex_lock(&sh_info->lock);
1471
    ASSERT(sh_info->refcount);
1472
    if (--sh_info->refcount == 0) {
1473
        dealloc = true;
1474
        bool cond;
1475
 
1476
        /*
1477
         * Now walk carefully the pagemap B+tree and free/remove
1478
         * reference from all frames found there.
1479
         */
1480
        for (cond = true; cond;) {
1481
            btree_node_t *node;
1482
 
1483
            ASSERT(!list_empty(&sh_info->pagemap.leaf_head));
1484
            node = list_get_instance(sh_info->pagemap.leaf_head.next, btree_node_t, leaf_link);
1485
            if ((cond = node->keys)) {
1486
                frame_free(ADDR2PFN((__address) node->value[0]));
1487
                btree_remove(&sh_info->pagemap, node->key[0], node);
1488
            }
1489
        }
1490
 
1491
    }
1492
    mutex_unlock(&sh_info->lock);
1493
 
1494
    if (dealloc) {
1495
        btree_destroy(&sh_info->pagemap);
1496
        free(sh_info);
1497
    }
1498
}
1499
 
1411 jermar 1500
static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);
1409 jermar 1501
static void anon_frame_free(as_area_t *area, __address page, __address frame);
1502
 
1235 jermar 1503
/*
1409 jermar 1504
 * Anonymous memory backend.
1505
 */
1506
mem_backend_t anon_backend = {
1507
    .backend_page_fault = anon_page_fault,
1508
    .backend_frame_free = anon_frame_free
1509
};
1510
 
1511
/** Service a page fault in the anonymous memory address space area.
1512
 *
1513
 * The address space area and page tables must be already locked.
1514
 *
1515
 * @param area Pointer to the address space area.
1516
 * @param addr Faulting virtual address.
1411 jermar 1517
 * @param access Access mode that caused the fault (i.e. read/write/exec).
1409 jermar 1518
 *
1519
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
1520
 */
1411 jermar 1521
int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)
1409 jermar 1522
{
1523
    __address frame;
1524
 
1423 jermar 1525
    if (!as_area_check_access(area, access))
1526
        return AS_PF_FAULT;
1527
 
1409 jermar 1528
    if (area->sh_info) {
1529
        btree_node_t *leaf;
1530
 
1531
        /*
1532
         * The area is shared, chances are that the mapping can be found
1533
         * in the pagemap of the address space area share info structure.
1534
         * In the case that the pagemap does not contain the respective
1535
         * mapping, a new frame is allocated and the mapping is created.
1536
         */
1537
        mutex_lock(&area->sh_info->lock);
1413 jermar 1538
        frame = (__address) btree_search(&area->sh_info->pagemap,
1539
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
1409 jermar 1540
        if (!frame) {
1541
            bool allocate = true;
1542
            int i;
1543
 
1544
            /*
1545
             * Zero can be returned as a valid frame address.
1546
             * Just a small workaround.
1547
             */
1548
            for (i = 0; i < leaf->keys; i++) {
1549
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
1550
                    allocate = false;
1551
                    break;
1552
                }
1553
            }
1554
            if (allocate) {
1555
                frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1556
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
1557
 
1558
                /*
1559
                 * Insert the address of the newly allocated frame to the pagemap.
1560
                 */
1413 jermar 1561
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);
1409 jermar 1562
            }
1563
        }
1564
        mutex_unlock(&area->sh_info->lock);
1565
    } else {
1566
 
1567
        /*
1568
         * In general, there can be several reasons that
1569
         * can have caused this fault.
1570
         *
1571
         * - non-existent mapping: the area is an anonymous
1572
         *   area (e.g. heap or stack) and so far has not been
1573
         *   allocated a frame for the faulting page
1574
         *
1575
         * - non-present mapping: another possibility,
1576
         *   currently not implemented, would be frame
1577
         *   reuse; when this becomes a possibility,
1578
         *   do not forget to distinguish between
1579
         *   the different causes
1580
         */
1581
        frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1582
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
1583
    }
1584
 
1585
    /*
1586
     * Map 'page' to 'frame'.
1587
     * Note that TLB shootdown is not attempted as only new information is being
1588
     * inserted into page tables.
1589
     */
1590
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1591
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
1592
        panic("Could not insert used space.\n");
1593
 
1594
    return AS_PF_OK;
1595
}
1596
 
1597
/** Free a frame that is backed by the anonymous memory backend.
1598
 *
1599
 * The address space area and page tables must be already locked.
1600
 *
1601
 * @param area Ignored.
1602
 * @param page Ignored.
1603
 * @param frame Frame to be released.
1604
 */
1605
void anon_frame_free(as_area_t *area, __address page, __address frame)
1606
{
1607
    frame_free(ADDR2PFN(frame));
1608
}
1609
 
1610
/*
1235 jermar 1611
 * Address space related syscalls.
1612
 */
1613
 
1614
/** Wrapper for as_area_create(). */
1615
__native sys_as_area_create(__address address, size_t size, int flags)
1616
{
1409 jermar 1617
    if (as_area_create(AS, flags, size, address, AS_AREA_ATTR_NONE, &anon_backend, NULL))
1235 jermar 1618
        return (__native) address;
1619
    else
1620
        return (__native) -1;
1621
}
1622
 
1623
/** Wrapper for as_area_resize. */
1624
__native sys_as_area_resize(__address address, size_t size, int flags)
1625
{
1306 jermar 1626
    return (__native) as_area_resize(AS, address, size, 0);
1235 jermar 1627
}
1628
 
1306 jermar 1629
/** Wrapper for as_area_destroy. */
1630
__native sys_as_area_destroy(__address address)
1631
{
1632
    return (__native) as_area_destroy(AS, address);
1633
}