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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
 
1380 jermar 86
/** Address space lock. It protects inactive_as_with_asid_head. Must be acquired before as_t mutex. */
823 jermar 87
SPINLOCK_INITIALIZE(as_lock);
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
 
823 jermar 131
    as->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
{
140
    ASSERT(as->refcount == 0);
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
 
1329 palkovsky 453
/** Steal address space area from another task.
1235 jermar 454
 *
1329 palkovsky 455
 * Address space area is stolen from another task
456
 * Moreover, any existing mapping
1235 jermar 457
 * is copied as well, providing thus a mechanism
458
 * for sharing group of pages. The source address
459
 * space area and any associated mapping is preserved.
460
 *
1329 palkovsky 461
 * @param src_task Pointer of source task
1239 jermar 462
 * @param src_base Base address of the source address space area.
1329 palkovsky 463
 * @param acc_size Expected size of the source area
464
 * @param dst_base Target base address
1235 jermar 465
 *
1306 jermar 466
 * @return Zero on success or ENOENT if there is no such task or
1235 jermar 467
 *     if there is no such address space area,
468
 *     EPERM if there was a problem in accepting the area or
469
 *     ENOMEM if there was a problem in allocating destination
470
 *     address space area.
471
 */
1329 palkovsky 472
int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,
473
          __address dst_base)
1235 jermar 474
{
475
    ipl_t ipl;
476
    count_t i;
1329 palkovsky 477
    as_t *src_as;      
1239 jermar 478
    int src_flags;
479
    size_t src_size;
480
    as_area_t *src_area, *dst_area;
1329 palkovsky 481
 
1235 jermar 482
    ipl = interrupts_disable();
1329 palkovsky 483
    spinlock_lock(&src_task->lock);
484
    src_as = src_task->as;
1235 jermar 485
 
1380 jermar 486
    mutex_lock(&src_as->lock);
1329 palkovsky 487
    src_area = find_area_and_lock(src_as, src_base);
1239 jermar 488
    if (!src_area) {
1238 jermar 489
        /*
490
         * Could not find the source address space area.
491
         */
1329 palkovsky 492
        spinlock_unlock(&src_task->lock);
1380 jermar 493
        mutex_unlock(&src_as->lock);
1238 jermar 494
        interrupts_restore(ipl);
495
        return ENOENT;
496
    }
1239 jermar 497
    src_size = src_area->pages * PAGE_SIZE;
498
    src_flags = src_area->flags;
1380 jermar 499
    mutex_unlock(&src_area->lock);
500
    mutex_unlock(&src_as->lock);
1235 jermar 501
 
1329 palkovsky 502
    if (src_size != acc_size) {
503
        spinlock_unlock(&src_task->lock);
1235 jermar 504
        interrupts_restore(ipl);
505
        return EPERM;
506
    }
507
    /*
1239 jermar 508
     * Create copy of the source address space area.
509
     * The destination area is created with AS_AREA_ATTR_PARTIAL
510
     * attribute set which prevents race condition with
511
     * preliminary as_page_fault() calls.
1235 jermar 512
     */
1409 jermar 513
    dst_area = as_area_create(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL, &anon_backend, NULL);
1239 jermar 514
    if (!dst_area) {
1235 jermar 515
        /*
516
         * Destination address space area could not be created.
517
         */
1329 palkovsky 518
        spinlock_unlock(&src_task->lock);
1235 jermar 519
        interrupts_restore(ipl);
520
        return ENOMEM;
521
    }
522
 
1329 palkovsky 523
    spinlock_unlock(&src_task->lock);
1235 jermar 524
 
525
    /*
526
     * Avoid deadlock by first locking the address space with lower address.
527
     */
1329 palkovsky 528
    if (AS < src_as) {
1380 jermar 529
        mutex_lock(&AS->lock);
530
        mutex_lock(&src_as->lock);
1235 jermar 531
    } else {
1380 jermar 532
        mutex_lock(&AS->lock);
533
        mutex_lock(&src_as->lock);
1235 jermar 534
    }
535
 
1239 jermar 536
    for (i = 0; i < SIZE2FRAMES(src_size); i++) {
1235 jermar 537
        pte_t *pte;
538
        __address frame;
539
 
1329 palkovsky 540
        page_table_lock(src_as, false);
541
        pte = page_mapping_find(src_as, src_base + i*PAGE_SIZE);
1235 jermar 542
        if (pte && PTE_VALID(pte)) {
543
            ASSERT(PTE_PRESENT(pte));
544
            frame = PTE_GET_FRAME(pte);
1239 jermar 545
            if (!(src_flags & AS_AREA_DEVICE))
1236 jermar 546
                frame_reference_add(ADDR2PFN(frame));
1329 palkovsky 547
            page_table_unlock(src_as, false);
1235 jermar 548
        } else {
1329 palkovsky 549
            page_table_unlock(src_as, false);
1235 jermar 550
            continue;
551
        }
552
 
1329 palkovsky 553
        page_table_lock(AS, false);
554
        page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
555
        page_table_unlock(AS, false);
1235 jermar 556
    }
1239 jermar 557
 
558
    /*
559
     * Now the destination address space area has been
560
     * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
561
     * attribute.
562
     */
1380 jermar 563
    mutex_lock(&dst_area->lock);
1239 jermar 564
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
1380 jermar 565
    mutex_unlock(&dst_area->lock);
1235 jermar 566
 
1380 jermar 567
    mutex_unlock(&AS->lock);
568
    mutex_unlock(&src_as->lock);
1235 jermar 569
    interrupts_restore(ipl);
570
 
571
    return 0;
572
}
573
 
754 jermar 574
/** Initialize mapping for one page of address space.
703 jermar 575
 *
754 jermar 576
 * This functions maps 'page' to 'frame' according
577
 * to attributes of the address space area to
578
 * wich 'page' belongs.
703 jermar 579
 *
840 jermar 580
 * @param as Target address space.
754 jermar 581
 * @param page Virtual page within the area.
582
 * @param frame Physical frame to which page will be mapped.
703 jermar 583
 */
754 jermar 584
void as_set_mapping(as_t *as, __address page, __address frame)
703 jermar 585
{
977 jermar 586
    as_area_t *area;
703 jermar 587
    ipl_t ipl;
588
 
589
    ipl = interrupts_disable();
1044 jermar 590
    page_table_lock(as, true);
703 jermar 591
 
977 jermar 592
    area = find_area_and_lock(as, page);
754 jermar 593
    if (!area) {
1403 jermar 594
        panic("Page not part of any as_area.\n");
754 jermar 595
    }
596
 
1409 jermar 597
    ASSERT(!area->backend);
598
 
599
    page_mapping_insert(as, page, frame, as_area_get_flags(area));
1403 jermar 600
    if (!used_space_insert(area, page, 1))
601
        panic("Could not insert used space.\n");
754 jermar 602
 
1380 jermar 603
    mutex_unlock(&area->lock);
1044 jermar 604
    page_table_unlock(as, true);
703 jermar 605
    interrupts_restore(ipl);
606
}
607
 
608
/** Handle page fault within the current address space.
609
 *
1409 jermar 610
 * This is the high-level page fault handler. It decides
611
 * whether the page fault can be resolved by any backend
612
 * and if so, it invokes the backend to resolve the page
613
 * fault.
614
 *
703 jermar 615
 * Interrupts are assumed disabled.
616
 *
617
 * @param page Faulting page.
1411 jermar 618
 * @param access Access mode that caused the fault (i.e. read/write/exec).
1288 jermar 619
 * @param istate Pointer to interrupted state.
703 jermar 620
 *
1409 jermar 621
 * @return AS_PF_FAULT on page fault, AS_PF_OK on success or AS_PF_DEFER if the
622
 *     fault was caused by copy_to_uspace() or copy_from_uspace().
703 jermar 623
 */
1411 jermar 624
int as_page_fault(__address page, pf_access_t access, istate_t *istate)
703 jermar 625
{
1044 jermar 626
    pte_t *pte;
977 jermar 627
    as_area_t *area;
703 jermar 628
 
1380 jermar 629
    if (!THREAD)
1409 jermar 630
        return AS_PF_FAULT;
1380 jermar 631
 
703 jermar 632
    ASSERT(AS);
1044 jermar 633
 
1380 jermar 634
    mutex_lock(&AS->lock);
977 jermar 635
    area = find_area_and_lock(AS, page);   
703 jermar 636
    if (!area) {
637
        /*
638
         * No area contained mapping for 'page'.
639
         * Signal page fault to low-level handler.
640
         */
1380 jermar 641
        mutex_unlock(&AS->lock);
1288 jermar 642
        goto page_fault;
703 jermar 643
    }
644
 
1239 jermar 645
    if (area->attributes & AS_AREA_ATTR_PARTIAL) {
646
        /*
647
         * The address space area is not fully initialized.
648
         * Avoid possible race by returning error.
649
         */
1380 jermar 650
        mutex_unlock(&area->lock);
651
        mutex_unlock(&AS->lock);
1288 jermar 652
        goto page_fault;       
1239 jermar 653
    }
654
 
1409 jermar 655
    if (!area->backend || !area->backend->backend_page_fault) {
656
        /*
657
         * The address space area is not backed by any backend
658
         * or the backend cannot handle page faults.
659
         */
660
        mutex_unlock(&area->lock);
661
        mutex_unlock(&AS->lock);
662
        goto page_fault;       
663
    }
1179 jermar 664
 
1044 jermar 665
    page_table_lock(AS, false);
666
 
703 jermar 667
    /*
1044 jermar 668
     * To avoid race condition between two page faults
669
     * on the same address, we need to make sure
670
     * the mapping has not been already inserted.
671
     */
672
    if ((pte = page_mapping_find(AS, page))) {
673
        if (PTE_PRESENT(pte)) {
674
            page_table_unlock(AS, false);
1380 jermar 675
            mutex_unlock(&area->lock);
676
            mutex_unlock(&AS->lock);
1409 jermar 677
            return AS_PF_OK;
1044 jermar 678
        }
679
    }
1409 jermar 680
 
1044 jermar 681
    /*
1409 jermar 682
     * Resort to the backend page fault handler.
703 jermar 683
     */
1411 jermar 684
    if (area->backend->backend_page_fault(area, page, access) != AS_PF_OK) {
1409 jermar 685
        page_table_unlock(AS, false);
686
        mutex_unlock(&area->lock);
687
        mutex_unlock(&AS->lock);
688
        goto page_fault;
689
    }
703 jermar 690
 
1044 jermar 691
    page_table_unlock(AS, false);
1380 jermar 692
    mutex_unlock(&area->lock);
693
    mutex_unlock(&AS->lock);
1288 jermar 694
    return AS_PF_OK;
695
 
696
page_fault:
697
    if (THREAD->in_copy_from_uspace) {
698
        THREAD->in_copy_from_uspace = false;
699
        istate_set_retaddr(istate, (__address) &memcpy_from_uspace_failover_address);
700
    } else if (THREAD->in_copy_to_uspace) {
701
        THREAD->in_copy_to_uspace = false;
702
        istate_set_retaddr(istate, (__address) &memcpy_to_uspace_failover_address);
703
    } else {
704
        return AS_PF_FAULT;
705
    }
706
 
707
    return AS_PF_DEFER;
703 jermar 708
}
709
 
823 jermar 710
/** Switch address spaces.
703 jermar 711
 *
1380 jermar 712
 * Note that this function cannot sleep as it is essentially a part of
713
 * the scheduling. Sleeping here would lead to deadlock on wakeup.
714
 *
823 jermar 715
 * @param old Old address space or NULL.
716
 * @param new New address space.
703 jermar 717
 */
823 jermar 718
void as_switch(as_t *old, as_t *new)
703 jermar 719
{
720
    ipl_t ipl;
823 jermar 721
    bool needs_asid = false;
703 jermar 722
 
723
    ipl = interrupts_disable();
823 jermar 724
    spinlock_lock(&as_lock);
703 jermar 725
 
726
    /*
823 jermar 727
     * First, take care of the old address space.
728
     */
729
    if (old) {
1380 jermar 730
        mutex_lock_active(&old->lock);
823 jermar 731
        ASSERT(old->refcount);
732
        if((--old->refcount == 0) && (old != AS_KERNEL)) {
733
            /*
734
             * The old address space is no longer active on
735
             * any processor. It can be appended to the
736
             * list of inactive address spaces with assigned
737
             * ASID.
738
             */
739
             ASSERT(old->asid != ASID_INVALID);
740
             list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
741
        }
1380 jermar 742
        mutex_unlock(&old->lock);
823 jermar 743
    }
744
 
745
    /*
746
     * Second, prepare the new address space.
747
     */
1380 jermar 748
    mutex_lock_active(&new->lock);
823 jermar 749
    if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
750
        if (new->asid != ASID_INVALID)
751
            list_remove(&new->inactive_as_with_asid_link);
752
        else
753
            needs_asid = true;  /* defer call to asid_get() until new->lock is released */
754
    }
755
    SET_PTL0_ADDRESS(new->page_table);
1380 jermar 756
    mutex_unlock(&new->lock);
823 jermar 757
 
758
    if (needs_asid) {
759
        /*
760
         * Allocation of new ASID was deferred
761
         * until now in order to avoid deadlock.
762
         */
763
        asid_t asid;
764
 
765
        asid = asid_get();
1380 jermar 766
        mutex_lock_active(&new->lock);
823 jermar 767
        new->asid = asid;
1380 jermar 768
        mutex_unlock(&new->lock);
823 jermar 769
    }
770
    spinlock_unlock(&as_lock);
771
    interrupts_restore(ipl);
772
 
773
    /*
703 jermar 774
     * Perform architecture-specific steps.
727 jermar 775
     * (e.g. write ASID to hardware register etc.)
703 jermar 776
     */
823 jermar 777
    as_install_arch(new);
703 jermar 778
 
823 jermar 779
    AS = new;
703 jermar 780
}
754 jermar 781
 
1235 jermar 782
/** Convert address space area flags to page flags.
754 jermar 783
 *
1235 jermar 784
 * @param aflags Flags of some address space area.
754 jermar 785
 *
1235 jermar 786
 * @return Flags to be passed to page_mapping_insert().
754 jermar 787
 */
1235 jermar 788
int area_flags_to_page_flags(int aflags)
754 jermar 789
{
790
    int flags;
791
 
1178 jermar 792
    flags = PAGE_USER | PAGE_PRESENT;
754 jermar 793
 
1235 jermar 794
    if (aflags & AS_AREA_READ)
1026 jermar 795
        flags |= PAGE_READ;
796
 
1235 jermar 797
    if (aflags & AS_AREA_WRITE)
1026 jermar 798
        flags |= PAGE_WRITE;
799
 
1235 jermar 800
    if (aflags & AS_AREA_EXEC)
1026 jermar 801
        flags |= PAGE_EXEC;
802
 
1235 jermar 803
    if (!(aflags & AS_AREA_DEVICE))
1178 jermar 804
        flags |= PAGE_CACHEABLE;
805
 
754 jermar 806
    return flags;
807
}
756 jermar 808
 
1235 jermar 809
/** Compute flags for virtual address translation subsytem.
810
 *
811
 * The address space area must be locked.
812
 * Interrupts must be disabled.
813
 *
814
 * @param a Address space area.
815
 *
816
 * @return Flags to be used in page_mapping_insert().
817
 */
1409 jermar 818
int as_area_get_flags(as_area_t *a)
1235 jermar 819
{
820
    return area_flags_to_page_flags(a->flags);
821
}
822
 
756 jermar 823
/** Create page table.
824
 *
825
 * Depending on architecture, create either address space
826
 * private or global page table.
827
 *
828
 * @param flags Flags saying whether the page table is for kernel address space.
829
 *
830
 * @return First entry of the page table.
831
 */
832
pte_t *page_table_create(int flags)
833
{
834
        ASSERT(as_operations);
835
        ASSERT(as_operations->page_table_create);
836
 
837
        return as_operations->page_table_create(flags);
838
}
977 jermar 839
 
1044 jermar 840
/** Lock page table.
841
 *
842
 * This function should be called before any page_mapping_insert(),
843
 * page_mapping_remove() and page_mapping_find().
844
 *
845
 * Locking order is such that address space areas must be locked
846
 * prior to this call. Address space can be locked prior to this
847
 * call in which case the lock argument is false.
848
 *
849
 * @param as Address space.
1248 jermar 850
 * @param lock If false, do not attempt to lock as->lock.
1044 jermar 851
 */
852
void page_table_lock(as_t *as, bool lock)
853
{
854
    ASSERT(as_operations);
855
    ASSERT(as_operations->page_table_lock);
856
 
857
    as_operations->page_table_lock(as, lock);
858
}
859
 
860
/** Unlock page table.
861
 *
862
 * @param as Address space.
1248 jermar 863
 * @param unlock If false, do not attempt to unlock as->lock.
1044 jermar 864
 */
865
void page_table_unlock(as_t *as, bool unlock)
866
{
867
    ASSERT(as_operations);
868
    ASSERT(as_operations->page_table_unlock);
869
 
870
    as_operations->page_table_unlock(as, unlock);
871
}
872
 
977 jermar 873
 
874
/** Find address space area and lock it.
875
 *
876
 * The address space must be locked and interrupts must be disabled.
877
 *
878
 * @param as Address space.
879
 * @param va Virtual address.
880
 *
881
 * @return Locked address space area containing va on success or NULL on failure.
882
 */
883
as_area_t *find_area_and_lock(as_t *as, __address va)
884
{
885
    as_area_t *a;
1147 jermar 886
    btree_node_t *leaf, *lnode;
887
    int i;
977 jermar 888
 
1147 jermar 889
    a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf);
890
    if (a) {
891
        /* va is the base address of an address space area */
1380 jermar 892
        mutex_lock(&a->lock);
1147 jermar 893
        return a;
894
    }
895
 
896
    /*
1150 jermar 897
     * Search the leaf node and the righmost record of its left neighbour
1147 jermar 898
     * to find out whether this is a miss or va belongs to an address
899
     * space area found there.
900
     */
901
 
902
    /* First, search the leaf node itself. */
903
    for (i = 0; i < leaf->keys; i++) {
904
        a = (as_area_t *) leaf->value[i];
1380 jermar 905
        mutex_lock(&a->lock);
1147 jermar 906
        if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) {
907
            return a;
908
        }
1380 jermar 909
        mutex_unlock(&a->lock);
1147 jermar 910
    }
977 jermar 911
 
1147 jermar 912
    /*
1150 jermar 913
     * Second, locate the left neighbour and test its last record.
1148 jermar 914
     * Because of its position in the B+tree, it must have base < va.
1147 jermar 915
     */
1150 jermar 916
    if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 917
        a = (as_area_t *) lnode->value[lnode->keys - 1];
1380 jermar 918
        mutex_lock(&a->lock);
1147 jermar 919
        if (va < a->base + a->pages * PAGE_SIZE) {
1048 jermar 920
            return a;
1147 jermar 921
        }
1380 jermar 922
        mutex_unlock(&a->lock);
977 jermar 923
    }
924
 
925
    return NULL;
926
}
1048 jermar 927
 
928
/** Check area conflicts with other areas.
929
 *
930
 * The address space must be locked and interrupts must be disabled.
931
 *
932
 * @param as Address space.
933
 * @param va Starting virtual address of the area being tested.
934
 * @param size Size of the area being tested.
935
 * @param avoid_area Do not touch this area.
936
 *
937
 * @return True if there is no conflict, false otherwise.
938
 */
939
bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area)
940
{
941
    as_area_t *a;
1147 jermar 942
    btree_node_t *leaf, *node;
943
    int i;
1048 jermar 944
 
1070 jermar 945
    /*
946
     * We don't want any area to have conflicts with NULL page.
947
     */
948
    if (overlaps(va, size, NULL, PAGE_SIZE))
949
        return false;
950
 
1147 jermar 951
    /*
952
     * The leaf node is found in O(log n), where n is proportional to
953
     * the number of address space areas belonging to as.
954
     * The check for conflicts is then attempted on the rightmost
1150 jermar 955
     * record in the left neighbour, the leftmost record in the right
956
     * neighbour and all records in the leaf node itself.
1147 jermar 957
     */
1048 jermar 958
 
1147 jermar 959
    if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) {
960
        if (a != avoid_area)
961
            return false;
962
    }
963
 
964
    /* First, check the two border cases. */
1150 jermar 965
    if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 966
        a = (as_area_t *) node->value[node->keys - 1];
1380 jermar 967
        mutex_lock(&a->lock);
1147 jermar 968
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 969
            mutex_unlock(&a->lock);
1147 jermar 970
            return false;
971
        }
1380 jermar 972
        mutex_unlock(&a->lock);
1147 jermar 973
    }
1150 jermar 974
    if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 975
        a = (as_area_t *) node->value[0];
1380 jermar 976
        mutex_lock(&a->lock);
1147 jermar 977
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 978
            mutex_unlock(&a->lock);
1147 jermar 979
            return false;
980
        }
1380 jermar 981
        mutex_unlock(&a->lock);
1147 jermar 982
    }
983
 
984
    /* Second, check the leaf node. */
985
    for (i = 0; i < leaf->keys; i++) {
986
        a = (as_area_t *) leaf->value[i];
987
 
1048 jermar 988
        if (a == avoid_area)
989
            continue;
1147 jermar 990
 
1380 jermar 991
        mutex_lock(&a->lock);
1147 jermar 992
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 993
            mutex_unlock(&a->lock);
1147 jermar 994
            return false;
995
        }
1380 jermar 996
        mutex_unlock(&a->lock);
1048 jermar 997
    }
998
 
1070 jermar 999
    /*
1000
     * So far, the area does not conflict with other areas.
1001
     * Check if it doesn't conflict with kernel address space.
1002
     */  
1003
    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
1004
        return !overlaps(va, size,
1005
            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START);
1006
    }
1007
 
1048 jermar 1008
    return true;
1009
}
1235 jermar 1010
 
1380 jermar 1011
/** Return size of the address space area with given base.  */
1329 palkovsky 1012
size_t as_get_size(__address base)
1013
{
1014
    ipl_t ipl;
1015
    as_area_t *src_area;
1016
    size_t size;
1017
 
1018
    ipl = interrupts_disable();
1019
    src_area = find_area_and_lock(AS, base);
1020
    if (src_area){
1021
        size = src_area->pages * PAGE_SIZE;
1380 jermar 1022
        mutex_unlock(&src_area->lock);
1329 palkovsky 1023
    } else {
1024
        size = 0;
1025
    }
1026
    interrupts_restore(ipl);
1027
    return size;
1028
}
1029
 
1387 jermar 1030
/** Mark portion of address space area as used.
1031
 *
1032
 * The address space area must be already locked.
1033
 *
1034
 * @param a Address space area.
1035
 * @param page First page to be marked.
1036
 * @param count Number of page to be marked.
1037
 *
1038
 * @return 0 on failure and 1 on success.
1039
 */
1040
int used_space_insert(as_area_t *a, __address page, count_t count)
1041
{
1042
    btree_node_t *leaf, *node;
1043
    count_t pages;
1044
    int i;
1045
 
1046
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1047
    ASSERT(count);
1048
 
1049
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1050
    if (pages) {
1051
        /*
1052
         * We hit the beginning of some used space.
1053
         */
1054
        return 0;
1055
    }
1056
 
1057
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1058
    if (node) {
1059
        __address left_pg = node->key[node->keys - 1], right_pg = leaf->key[0];
1060
        count_t left_cnt = (count_t) node->value[node->keys - 1], right_cnt = (count_t) leaf->value[0];
1061
 
1062
        /*
1063
         * Examine the possibility that the interval fits
1064
         * somewhere between the rightmost interval of
1065
         * the left neigbour and the first interval of the leaf.
1066
         */
1067
 
1068
        if (page >= right_pg) {
1069
            /* Do nothing. */
1070
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1071
            /* The interval intersects with the left interval. */
1072
            return 0;
1073
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1074
            /* The interval intersects with the right interval. */
1075
            return 0;          
1076
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1077
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1078
            node->value[node->keys - 1] += count + right_cnt;
1387 jermar 1079
            btree_remove(&a->used_space, right_pg, leaf);
1080
            return 1;
1081
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1082
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1083
            node->value[node->keys - 1] += count;
1387 jermar 1084
            return 1;
1085
        } else if (page + count*PAGE_SIZE == right_pg) {
1086
            /*
1087
             * The interval can be addded by simply moving base of the right
1088
             * interval down and increasing its size accordingly.
1089
             */
1403 jermar 1090
            leaf->value[0] += count;
1387 jermar 1091
            leaf->key[0] = page;
1092
            return 1;
1093
        } else {
1094
            /*
1095
             * The interval is between both neigbouring intervals,
1096
             * but cannot be merged with any of them.
1097
             */
1098
            btree_insert(&a->used_space, page, (void *) count, leaf);
1099
            return 1;
1100
        }
1101
    } else if (page < leaf->key[0]) {
1102
        __address right_pg = leaf->key[0];
1103
        count_t right_cnt = (count_t) leaf->value[0];
1104
 
1105
        /*
1106
         * Investigate the border case in which the left neighbour does not
1107
         * exist but the interval fits from the left.
1108
         */
1109
 
1110
        if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1111
            /* The interval intersects with the right interval. */
1112
            return 0;
1113
        } else if (page + count*PAGE_SIZE == right_pg) {
1114
            /*
1115
             * The interval can be added by moving the base of the right interval down
1116
             * and increasing its size accordingly.
1117
             */
1118
            leaf->key[0] = page;
1403 jermar 1119
            leaf->value[0] += count;
1387 jermar 1120
            return 1;
1121
        } else {
1122
            /*
1123
             * The interval doesn't adjoin with the right interval.
1124
             * It must be added individually.
1125
             */
1126
            btree_insert(&a->used_space, page, (void *) count, leaf);
1127
            return 1;
1128
        }
1129
    }
1130
 
1131
    node = btree_leaf_node_right_neighbour(&a->used_space, leaf);
1132
    if (node) {
1133
        __address left_pg = leaf->key[leaf->keys - 1], right_pg = node->key[0];
1134
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1], right_cnt = (count_t) node->value[0];
1135
 
1136
        /*
1137
         * Examine the possibility that the interval fits
1138
         * somewhere between the leftmost interval of
1139
         * the right neigbour and the last interval of the leaf.
1140
         */
1141
 
1142
        if (page < left_pg) {
1143
            /* Do nothing. */
1144
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1145
            /* The interval intersects with the left interval. */
1146
            return 0;
1147
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1148
            /* The interval intersects with the right interval. */
1149
            return 0;          
1150
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1151
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1152
            leaf->value[leaf->keys - 1] += count + right_cnt;
1387 jermar 1153
            btree_remove(&a->used_space, right_pg, node);
1154
            return 1;
1155
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1156
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1157
            leaf->value[leaf->keys - 1] +=  count;
1387 jermar 1158
            return 1;
1159
        } else if (page + count*PAGE_SIZE == right_pg) {
1160
            /*
1161
             * The interval can be addded by simply moving base of the right
1162
             * interval down and increasing its size accordingly.
1163
             */
1403 jermar 1164
            node->value[0] += count;
1387 jermar 1165
            node->key[0] = page;
1166
            return 1;
1167
        } else {
1168
            /*
1169
             * The interval is between both neigbouring intervals,
1170
             * but cannot be merged with any of them.
1171
             */
1172
            btree_insert(&a->used_space, page, (void *) count, leaf);
1173
            return 1;
1174
        }
1175
    } else if (page >= leaf->key[leaf->keys - 1]) {
1176
        __address left_pg = leaf->key[leaf->keys - 1];
1177
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1178
 
1179
        /*
1180
         * Investigate the border case in which the right neighbour does not
1181
         * exist but the interval fits from the right.
1182
         */
1183
 
1184
        if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1403 jermar 1185
            /* The interval intersects with the left interval. */
1387 jermar 1186
            return 0;
1187
        } else if (left_pg + left_cnt*PAGE_SIZE == page) {
1188
            /* The interval can be added by growing the left interval. */
1403 jermar 1189
            leaf->value[leaf->keys - 1] += count;
1387 jermar 1190
            return 1;
1191
        } else {
1192
            /*
1193
             * The interval doesn't adjoin with the left interval.
1194
             * It must be added individually.
1195
             */
1196
            btree_insert(&a->used_space, page, (void *) count, leaf);
1197
            return 1;
1198
        }
1199
    }
1200
 
1201
    /*
1202
     * Note that if the algorithm made it thus far, the interval can fit only
1203
     * between two other intervals of the leaf. The two border cases were already
1204
     * resolved.
1205
     */
1206
    for (i = 1; i < leaf->keys; i++) {
1207
        if (page < leaf->key[i]) {
1208
            __address left_pg = leaf->key[i - 1], right_pg = leaf->key[i];
1209
            count_t left_cnt = (count_t) leaf->value[i - 1], right_cnt = (count_t) leaf->value[i];
1210
 
1211
            /*
1212
             * The interval fits between left_pg and right_pg.
1213
             */
1214
 
1215
            if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1216
                /* The interval intersects with the left interval. */
1217
                return 0;
1218
            } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1219
                /* The interval intersects with the right interval. */
1220
                return 0;          
1221
            } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1222
                /* The interval can be added by merging the two already present intervals. */
1403 jermar 1223
                leaf->value[i - 1] += count + right_cnt;
1387 jermar 1224
                btree_remove(&a->used_space, right_pg, leaf);
1225
                return 1;
1226
            } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1227
                /* The interval can be added by simply growing the left interval. */
1403 jermar 1228
                leaf->value[i - 1] += count;
1387 jermar 1229
                return 1;
1230
            } else if (page + count*PAGE_SIZE == right_pg) {
1231
                /*
1232
                     * The interval can be addded by simply moving base of the right
1233
                 * interval down and increasing its size accordingly.
1234
                 */
1403 jermar 1235
                leaf->value[i] += count;
1387 jermar 1236
                leaf->key[i] = page;
1237
                return 1;
1238
            } else {
1239
                /*
1240
                 * The interval is between both neigbouring intervals,
1241
                 * but cannot be merged with any of them.
1242
                 */
1243
                btree_insert(&a->used_space, page, (void *) count, leaf);
1244
                return 1;
1245
            }
1246
        }
1247
    }
1248
 
1249
    panic("Inconsistency detected while adding %d pages of used space at %P.\n", count, page);
1250
}
1251
 
1252
/** Mark portion of address space area as unused.
1253
 *
1254
 * The address space area must be already locked.
1255
 *
1256
 * @param a Address space area.
1257
 * @param page First page to be marked.
1258
 * @param count Number of page to be marked.
1259
 *
1260
 * @return 0 on failure and 1 on success.
1261
 */
1262
int used_space_remove(as_area_t *a, __address page, count_t count)
1263
{
1264
    btree_node_t *leaf, *node;
1265
    count_t pages;
1266
    int i;
1267
 
1268
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1269
    ASSERT(count);
1270
 
1271
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1272
    if (pages) {
1273
        /*
1274
         * We are lucky, page is the beginning of some interval.
1275
         */
1276
        if (count > pages) {
1277
            return 0;
1278
        } else if (count == pages) {
1279
            btree_remove(&a->used_space, page, leaf);
1403 jermar 1280
            return 1;
1387 jermar 1281
        } else {
1282
            /*
1283
             * Find the respective interval.
1284
             * Decrease its size and relocate its start address.
1285
             */
1286
            for (i = 0; i < leaf->keys; i++) {
1287
                if (leaf->key[i] == page) {
1288
                    leaf->key[i] += count*PAGE_SIZE;
1403 jermar 1289
                    leaf->value[i] -= count;
1387 jermar 1290
                    return 1;
1291
                }
1292
            }
1293
            goto error;
1294
        }
1295
    }
1296
 
1297
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1298
    if (node && page < leaf->key[0]) {
1299
        __address left_pg = node->key[node->keys - 1];
1300
        count_t left_cnt = (count_t) node->value[node->keys - 1];
1301
 
1302
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1303
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1304
                /*
1305
                 * The interval is contained in the rightmost interval
1306
                 * of the left neighbour and can be removed by
1307
                 * updating the size of the bigger interval.
1308
                 */
1403 jermar 1309
                node->value[node->keys - 1] -= count;
1387 jermar 1310
                return 1;
1311
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1312
                count_t new_cnt;
1387 jermar 1313
 
1314
                /*
1315
                 * The interval is contained in the rightmost interval
1316
                 * of the left neighbour but its removal requires
1317
                 * both updating the size of the original interval and
1318
                 * also inserting a new interval.
1319
                 */
1403 jermar 1320
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1321
                node->value[node->keys - 1] -= count + new_cnt;
1387 jermar 1322
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1323
                return 1;
1324
            }
1325
        }
1326
        return 0;
1327
    } else if (page < leaf->key[0]) {
1328
        return 0;
1329
    }
1330
 
1331
    if (page > leaf->key[leaf->keys - 1]) {
1332
        __address left_pg = leaf->key[leaf->keys - 1];
1333
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1334
 
1335
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1336
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1337
                /*
1338
                 * The interval is contained in the rightmost interval
1339
                 * of the leaf and can be removed by updating the size
1340
                 * of the bigger interval.
1341
                 */
1403 jermar 1342
                leaf->value[leaf->keys - 1] -= count;
1387 jermar 1343
                return 1;
1344
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1345
                count_t new_cnt;
1387 jermar 1346
 
1347
                /*
1348
                 * The interval is contained in the rightmost interval
1349
                 * of the leaf but its removal requires both updating
1350
                 * the size of the original interval and
1351
                 * also inserting a new interval.
1352
                 */
1403 jermar 1353
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1354
                leaf->value[leaf->keys - 1] -= count + new_cnt;
1387 jermar 1355
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1356
                return 1;
1357
            }
1358
        }
1359
        return 0;
1360
    }  
1361
 
1362
    /*
1363
     * The border cases have been already resolved.
1364
     * Now the interval can be only between intervals of the leaf.
1365
     */
1366
    for (i = 1; i < leaf->keys - 1; i++) {
1367
        if (page < leaf->key[i]) {
1368
            __address left_pg = leaf->key[i - 1];
1369
            count_t left_cnt = (count_t) leaf->value[i - 1];
1370
 
1371
            /*
1372
             * Now the interval is between intervals corresponding to (i - 1) and i.
1373
             */
1374
            if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1375
                if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1376
                    /*
1377
                    * The interval is contained in the interval (i - 1)
1378
                     * of the leaf and can be removed by updating the size
1379
                     * of the bigger interval.
1380
                     */
1403 jermar 1381
                    leaf->value[i - 1] -= count;
1387 jermar 1382
                    return 1;
1383
                } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1384
                    count_t new_cnt;
1387 jermar 1385
 
1386
                    /*
1387
                     * The interval is contained in the interval (i - 1)
1388
                     * of the leaf but its removal requires both updating
1389
                     * the size of the original interval and
1390
                     * also inserting a new interval.
1391
                     */
1403 jermar 1392
                    new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1393
                    leaf->value[i - 1] -= count + new_cnt;
1387 jermar 1394
                    btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1395
                    return 1;
1396
                }
1397
            }
1398
            return 0;
1399
        }
1400
    }
1401
 
1402
error:
1403
    panic("Inconsistency detected while removing %d pages of used space from %P.\n", count, page);
1404
}
1405
 
1409 jermar 1406
/** Remove reference to address space area share info.
1407
 *
1408
 * If the reference count drops to 0, the sh_info is deallocated.
1409
 *
1410
 * @param sh_info Pointer to address space area share info.
1411
 */
1412
void sh_info_remove_reference(share_info_t *sh_info)
1413
{
1414
    bool dealloc = false;
1415
 
1416
    mutex_lock(&sh_info->lock);
1417
    ASSERT(sh_info->refcount);
1418
    if (--sh_info->refcount == 0) {
1419
        dealloc = true;
1420
        bool cond;
1421
 
1422
        /*
1423
         * Now walk carefully the pagemap B+tree and free/remove
1424
         * reference from all frames found there.
1425
         */
1426
        for (cond = true; cond;) {
1427
            btree_node_t *node;
1428
 
1429
            ASSERT(!list_empty(&sh_info->pagemap.leaf_head));
1430
            node = list_get_instance(sh_info->pagemap.leaf_head.next, btree_node_t, leaf_link);
1431
            if ((cond = node->keys)) {
1432
                frame_free(ADDR2PFN((__address) node->value[0]));
1433
                btree_remove(&sh_info->pagemap, node->key[0], node);
1434
            }
1435
        }
1436
 
1437
    }
1438
    mutex_unlock(&sh_info->lock);
1439
 
1440
    if (dealloc) {
1441
        btree_destroy(&sh_info->pagemap);
1442
        free(sh_info);
1443
    }
1444
}
1445
 
1411 jermar 1446
static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);
1409 jermar 1447
static void anon_frame_free(as_area_t *area, __address page, __address frame);
1448
 
1235 jermar 1449
/*
1409 jermar 1450
 * Anonymous memory backend.
1451
 */
1452
mem_backend_t anon_backend = {
1453
    .backend_page_fault = anon_page_fault,
1454
    .backend_frame_free = anon_frame_free
1455
};
1456
 
1457
/** Service a page fault in the anonymous memory address space area.
1458
 *
1459
 * The address space area and page tables must be already locked.
1460
 *
1461
 * @param area Pointer to the address space area.
1462
 * @param addr Faulting virtual address.
1411 jermar 1463
 * @param access Access mode that caused the fault (i.e. read/write/exec).
1409 jermar 1464
 *
1465
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
1466
 */
1411 jermar 1467
int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)
1409 jermar 1468
{
1469
    __address frame;
1470
 
1471
    if (area->sh_info) {
1472
        btree_node_t *leaf;
1473
 
1474
        /*
1475
         * The area is shared, chances are that the mapping can be found
1476
         * in the pagemap of the address space area share info structure.
1477
         * In the case that the pagemap does not contain the respective
1478
         * mapping, a new frame is allocated and the mapping is created.
1479
         */
1480
        mutex_lock(&area->sh_info->lock);
1481
        frame = (__address) btree_search(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), &leaf);
1482
        if (!frame) {
1483
            bool allocate = true;
1484
            int i;
1485
 
1486
            /*
1487
             * Zero can be returned as a valid frame address.
1488
             * Just a small workaround.
1489
             */
1490
            for (i = 0; i < leaf->keys; i++) {
1491
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
1492
                    allocate = false;
1493
                    break;
1494
                }
1495
            }
1496
            if (allocate) {
1497
                frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1498
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
1499
 
1500
                /*
1501
                 * Insert the address of the newly allocated frame to the pagemap.
1502
                 */
1503
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), (void *) frame, leaf);
1504
            }
1505
        }
1506
        mutex_unlock(&area->sh_info->lock);
1507
    } else {
1508
 
1509
        /*
1510
         * In general, there can be several reasons that
1511
         * can have caused this fault.
1512
         *
1513
         * - non-existent mapping: the area is an anonymous
1514
         *   area (e.g. heap or stack) and so far has not been
1515
         *   allocated a frame for the faulting page
1516
         *
1517
         * - non-present mapping: another possibility,
1518
         *   currently not implemented, would be frame
1519
         *   reuse; when this becomes a possibility,
1520
         *   do not forget to distinguish between
1521
         *   the different causes
1522
         */
1523
        frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1524
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
1525
    }
1526
 
1527
    /*
1528
     * Map 'page' to 'frame'.
1529
     * Note that TLB shootdown is not attempted as only new information is being
1530
     * inserted into page tables.
1531
     */
1532
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1533
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
1534
        panic("Could not insert used space.\n");
1535
 
1536
    return AS_PF_OK;
1537
}
1538
 
1539
/** Free a frame that is backed by the anonymous memory backend.
1540
 *
1541
 * The address space area and page tables must be already locked.
1542
 *
1543
 * @param area Ignored.
1544
 * @param page Ignored.
1545
 * @param frame Frame to be released.
1546
 */
1547
void anon_frame_free(as_area_t *area, __address page, __address frame)
1548
{
1549
    frame_free(ADDR2PFN(frame));
1550
}
1551
 
1552
/*
1235 jermar 1553
 * Address space related syscalls.
1554
 */
1555
 
1556
/** Wrapper for as_area_create(). */
1557
__native sys_as_area_create(__address address, size_t size, int flags)
1558
{
1409 jermar 1559
    if (as_area_create(AS, flags, size, address, AS_AREA_ATTR_NONE, &anon_backend, NULL))
1235 jermar 1560
        return (__native) address;
1561
    else
1562
        return (__native) -1;
1563
}
1564
 
1565
/** Wrapper for as_area_resize. */
1566
__native sys_as_area_resize(__address address, size_t size, int flags)
1567
{
1306 jermar 1568
    return (__native) as_area_resize(AS, address, size, 0);
1235 jermar 1569
}
1570
 
1306 jermar 1571
/** Wrapper for as_area_destroy. */
1572
__native sys_as_area_destroy(__address address)
1573
{
1574
    return (__native) as_area_destroy(AS, address);
1575
}