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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;
378
 
379
    ipl = interrupts_disable();
1380 jermar 380
    mutex_lock(&as->lock);
1306 jermar 381
 
382
    area = find_area_and_lock(as, address);
383
    if (!area) {
1380 jermar 384
        mutex_unlock(&as->lock);
1306 jermar 385
        interrupts_restore(ipl);
386
        return ENOENT;
387
    }
388
 
1403 jermar 389
    base = area->base;
390
    if (!(area->flags & AS_AREA_DEVICE)) {
391
        bool cond; 
392
 
1306 jermar 393
        /*
394
         * Releasing physical memory.
395
         * Areas mapping memory-mapped devices are treated differently than
396
         * areas backing frame_alloc()'ed memory.
397
         */
1403 jermar 398
 
399
        /*
400
         * Visit only the pages mapped by used_space B+tree.
401
         * Note that we must be very careful when walking the tree
402
         * leaf list and removing used space as the leaf list changes
403
         * unpredictibly after each remove. The solution is to actually
404
         * not walk the tree at all, but to remove items from the head
405
         * of the leaf list until there are some keys left.
406
         */
407
        for (cond = true; cond;) {
408
            btree_node_t *node;
409
 
410
            ASSERT(!list_empty(&area->used_space.leaf_head));
411
            node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
412
            if ((cond = (bool) node->keys)) {
413
                __address b = node->key[0];
414
                count_t i;
415
                pte_t *pte;
416
 
417
                for (i = 0; i < (count_t) node->value[0]; i++) {
418
                    page_table_lock(as, false);
419
                    pte = page_mapping_find(as, b + i*PAGE_SIZE);
420
                    ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
1409 jermar 421
                    if (area->backend && area->backend->backend_frame_free) {
422
                        area->backend->backend_frame_free(area,
423
                            b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
424
                    }
1403 jermar 425
                    page_mapping_remove(as, b + i*PAGE_SIZE);
426
                    page_table_unlock(as, false);
427
                }
428
                if (!used_space_remove(area, b, i))
429
                    panic("Could not remove used space.\n");
1306 jermar 430
            }
431
        }
432
    }
1403 jermar 433
    btree_destroy(&area->used_space);
434
 
1306 jermar 435
    /*
436
     * Invalidate TLB's.
437
     */
438
    tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
439
    tlb_invalidate_pages(AS->asid, area->base, area->pages);
440
    tlb_shootdown_finalize();
441
 
1309 jermar 442
    area->attributes |= AS_AREA_ATTR_PARTIAL;
1409 jermar 443
 
444
    if (area->sh_info)
445
        sh_info_remove_reference(area->sh_info);
446
 
1380 jermar 447
    mutex_unlock(&area->lock);
1306 jermar 448
 
449
    /*
450
     * Remove the empty area from address space.
451
     */
452
    btree_remove(&AS->as_area_btree, base, NULL);
453
 
1309 jermar 454
    free(area);
455
 
1380 jermar 456
    mutex_unlock(&AS->lock);
1306 jermar 457
    interrupts_restore(ipl);
458
    return 0;
459
}
460
 
1329 palkovsky 461
/** Steal address space area from another task.
1235 jermar 462
 *
1329 palkovsky 463
 * Address space area is stolen from another task
464
 * Moreover, any existing mapping
1235 jermar 465
 * is copied as well, providing thus a mechanism
466
 * for sharing group of pages. The source address
467
 * space area and any associated mapping is preserved.
468
 *
1329 palkovsky 469
 * @param src_task Pointer of source task
1239 jermar 470
 * @param src_base Base address of the source address space area.
1329 palkovsky 471
 * @param acc_size Expected size of the source area
472
 * @param dst_base Target base address
1235 jermar 473
 *
1306 jermar 474
 * @return Zero on success or ENOENT if there is no such task or
1235 jermar 475
 *     if there is no such address space area,
476
 *     EPERM if there was a problem in accepting the area or
477
 *     ENOMEM if there was a problem in allocating destination
478
 *     address space area.
479
 */
1329 palkovsky 480
int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,
481
          __address dst_base)
1235 jermar 482
{
483
    ipl_t ipl;
484
    count_t i;
1329 palkovsky 485
    as_t *src_as;      
1239 jermar 486
    int src_flags;
487
    size_t src_size;
488
    as_area_t *src_area, *dst_area;
1329 palkovsky 489
 
1235 jermar 490
    ipl = interrupts_disable();
1329 palkovsky 491
    spinlock_lock(&src_task->lock);
492
    src_as = src_task->as;
1235 jermar 493
 
1380 jermar 494
    mutex_lock(&src_as->lock);
1329 palkovsky 495
    src_area = find_area_and_lock(src_as, src_base);
1239 jermar 496
    if (!src_area) {
1238 jermar 497
        /*
498
         * Could not find the source address space area.
499
         */
1329 palkovsky 500
        spinlock_unlock(&src_task->lock);
1380 jermar 501
        mutex_unlock(&src_as->lock);
1238 jermar 502
        interrupts_restore(ipl);
503
        return ENOENT;
504
    }
1239 jermar 505
    src_size = src_area->pages * PAGE_SIZE;
506
    src_flags = src_area->flags;
1380 jermar 507
    mutex_unlock(&src_area->lock);
508
    mutex_unlock(&src_as->lock);
1235 jermar 509
 
1329 palkovsky 510
    if (src_size != acc_size) {
511
        spinlock_unlock(&src_task->lock);
1235 jermar 512
        interrupts_restore(ipl);
513
        return EPERM;
514
    }
515
    /*
1239 jermar 516
     * Create copy of the source address space area.
517
     * The destination area is created with AS_AREA_ATTR_PARTIAL
518
     * attribute set which prevents race condition with
519
     * preliminary as_page_fault() calls.
1235 jermar 520
     */
1409 jermar 521
    dst_area = as_area_create(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL, &anon_backend, NULL);
1239 jermar 522
    if (!dst_area) {
1235 jermar 523
        /*
524
         * Destination address space area could not be created.
525
         */
1329 palkovsky 526
        spinlock_unlock(&src_task->lock);
1235 jermar 527
        interrupts_restore(ipl);
528
        return ENOMEM;
529
    }
530
 
1329 palkovsky 531
    spinlock_unlock(&src_task->lock);
1235 jermar 532
 
533
    /*
534
     * Avoid deadlock by first locking the address space with lower address.
535
     */
1329 palkovsky 536
    if (AS < src_as) {
1380 jermar 537
        mutex_lock(&AS->lock);
538
        mutex_lock(&src_as->lock);
1235 jermar 539
    } else {
1380 jermar 540
        mutex_lock(&AS->lock);
541
        mutex_lock(&src_as->lock);
1235 jermar 542
    }
543
 
1239 jermar 544
    for (i = 0; i < SIZE2FRAMES(src_size); i++) {
1235 jermar 545
        pte_t *pte;
546
        __address frame;
547
 
1329 palkovsky 548
        page_table_lock(src_as, false);
549
        pte = page_mapping_find(src_as, src_base + i*PAGE_SIZE);
1235 jermar 550
        if (pte && PTE_VALID(pte)) {
551
            ASSERT(PTE_PRESENT(pte));
552
            frame = PTE_GET_FRAME(pte);
1239 jermar 553
            if (!(src_flags & AS_AREA_DEVICE))
1236 jermar 554
                frame_reference_add(ADDR2PFN(frame));
1329 palkovsky 555
            page_table_unlock(src_as, false);
1235 jermar 556
        } else {
1329 palkovsky 557
            page_table_unlock(src_as, false);
1235 jermar 558
            continue;
559
        }
560
 
1329 palkovsky 561
        page_table_lock(AS, false);
562
        page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
563
        page_table_unlock(AS, false);
1235 jermar 564
    }
1239 jermar 565
 
566
    /*
567
     * Now the destination address space area has been
568
     * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
569
     * attribute.
570
     */
1380 jermar 571
    mutex_lock(&dst_area->lock);
1239 jermar 572
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
1380 jermar 573
    mutex_unlock(&dst_area->lock);
1235 jermar 574
 
1380 jermar 575
    mutex_unlock(&AS->lock);
576
    mutex_unlock(&src_as->lock);
1235 jermar 577
    interrupts_restore(ipl);
578
 
579
    return 0;
580
}
581
 
754 jermar 582
/** Initialize mapping for one page of address space.
703 jermar 583
 *
754 jermar 584
 * This functions maps 'page' to 'frame' according
585
 * to attributes of the address space area to
586
 * wich 'page' belongs.
703 jermar 587
 *
840 jermar 588
 * @param as Target address space.
754 jermar 589
 * @param page Virtual page within the area.
590
 * @param frame Physical frame to which page will be mapped.
703 jermar 591
 */
754 jermar 592
void as_set_mapping(as_t *as, __address page, __address frame)
703 jermar 593
{
977 jermar 594
    as_area_t *area;
703 jermar 595
    ipl_t ipl;
596
 
597
    ipl = interrupts_disable();
1044 jermar 598
    page_table_lock(as, true);
703 jermar 599
 
977 jermar 600
    area = find_area_and_lock(as, page);
754 jermar 601
    if (!area) {
1403 jermar 602
        panic("Page not part of any as_area.\n");
754 jermar 603
    }
604
 
1409 jermar 605
    ASSERT(!area->backend);
606
 
607
    page_mapping_insert(as, page, frame, as_area_get_flags(area));
1403 jermar 608
    if (!used_space_insert(area, page, 1))
609
        panic("Could not insert used space.\n");
754 jermar 610
 
1380 jermar 611
    mutex_unlock(&area->lock);
1044 jermar 612
    page_table_unlock(as, true);
703 jermar 613
    interrupts_restore(ipl);
614
}
615
 
616
/** Handle page fault within the current address space.
617
 *
1409 jermar 618
 * This is the high-level page fault handler. It decides
619
 * whether the page fault can be resolved by any backend
620
 * and if so, it invokes the backend to resolve the page
621
 * fault.
622
 *
703 jermar 623
 * Interrupts are assumed disabled.
624
 *
625
 * @param page Faulting page.
1288 jermar 626
 * @param istate Pointer to interrupted state.
703 jermar 627
 *
1409 jermar 628
 * @return AS_PF_FAULT on page fault, AS_PF_OK on success or AS_PF_DEFER if the
629
 *     fault was caused by copy_to_uspace() or copy_from_uspace().
703 jermar 630
 */
1288 jermar 631
int as_page_fault(__address page, istate_t *istate)
703 jermar 632
{
1044 jermar 633
    pte_t *pte;
977 jermar 634
    as_area_t *area;
703 jermar 635
 
1380 jermar 636
    if (!THREAD)
1409 jermar 637
        return AS_PF_FAULT;
1380 jermar 638
 
703 jermar 639
    ASSERT(AS);
1044 jermar 640
 
1380 jermar 641
    mutex_lock(&AS->lock);
977 jermar 642
    area = find_area_and_lock(AS, page);   
703 jermar 643
    if (!area) {
644
        /*
645
         * No area contained mapping for 'page'.
646
         * Signal page fault to low-level handler.
647
         */
1380 jermar 648
        mutex_unlock(&AS->lock);
1288 jermar 649
        goto page_fault;
703 jermar 650
    }
651
 
1239 jermar 652
    if (area->attributes & AS_AREA_ATTR_PARTIAL) {
653
        /*
654
         * The address space area is not fully initialized.
655
         * Avoid possible race by returning error.
656
         */
1380 jermar 657
        mutex_unlock(&area->lock);
658
        mutex_unlock(&AS->lock);
1288 jermar 659
        goto page_fault;       
1239 jermar 660
    }
661
 
1409 jermar 662
    if (!area->backend || !area->backend->backend_page_fault) {
663
        /*
664
         * The address space area is not backed by any backend
665
         * or the backend cannot handle page faults.
666
         */
667
        mutex_unlock(&area->lock);
668
        mutex_unlock(&AS->lock);
669
        goto page_fault;       
670
    }
1179 jermar 671
 
1044 jermar 672
    page_table_lock(AS, false);
673
 
703 jermar 674
    /*
1044 jermar 675
     * To avoid race condition between two page faults
676
     * on the same address, we need to make sure
677
     * the mapping has not been already inserted.
678
     */
679
    if ((pte = page_mapping_find(AS, page))) {
680
        if (PTE_PRESENT(pte)) {
681
            page_table_unlock(AS, false);
1380 jermar 682
            mutex_unlock(&area->lock);
683
            mutex_unlock(&AS->lock);
1409 jermar 684
            return AS_PF_OK;
1044 jermar 685
        }
686
    }
1409 jermar 687
 
1044 jermar 688
    /*
1409 jermar 689
     * Resort to the backend page fault handler.
703 jermar 690
     */
1409 jermar 691
    if (area->backend->backend_page_fault(area, page) != AS_PF_OK) {
692
        page_table_unlock(AS, false);
693
        mutex_unlock(&area->lock);
694
        mutex_unlock(&AS->lock);
695
        goto page_fault;
696
    }
703 jermar 697
 
1044 jermar 698
    page_table_unlock(AS, false);
1380 jermar 699
    mutex_unlock(&area->lock);
700
    mutex_unlock(&AS->lock);
1288 jermar 701
    return AS_PF_OK;
702
 
703
page_fault:
704
    if (THREAD->in_copy_from_uspace) {
705
        THREAD->in_copy_from_uspace = false;
706
        istate_set_retaddr(istate, (__address) &memcpy_from_uspace_failover_address);
707
    } else if (THREAD->in_copy_to_uspace) {
708
        THREAD->in_copy_to_uspace = false;
709
        istate_set_retaddr(istate, (__address) &memcpy_to_uspace_failover_address);
710
    } else {
711
        return AS_PF_FAULT;
712
    }
713
 
714
    return AS_PF_DEFER;
703 jermar 715
}
716
 
823 jermar 717
/** Switch address spaces.
703 jermar 718
 *
1380 jermar 719
 * Note that this function cannot sleep as it is essentially a part of
720
 * the scheduling. Sleeping here would lead to deadlock on wakeup.
721
 *
823 jermar 722
 * @param old Old address space or NULL.
723
 * @param new New address space.
703 jermar 724
 */
823 jermar 725
void as_switch(as_t *old, as_t *new)
703 jermar 726
{
727
    ipl_t ipl;
823 jermar 728
    bool needs_asid = false;
703 jermar 729
 
730
    ipl = interrupts_disable();
823 jermar 731
    spinlock_lock(&as_lock);
703 jermar 732
 
733
    /*
823 jermar 734
     * First, take care of the old address space.
735
     */
736
    if (old) {
1380 jermar 737
        mutex_lock_active(&old->lock);
823 jermar 738
        ASSERT(old->refcount);
739
        if((--old->refcount == 0) && (old != AS_KERNEL)) {
740
            /*
741
             * The old address space is no longer active on
742
             * any processor. It can be appended to the
743
             * list of inactive address spaces with assigned
744
             * ASID.
745
             */
746
             ASSERT(old->asid != ASID_INVALID);
747
             list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
748
        }
1380 jermar 749
        mutex_unlock(&old->lock);
823 jermar 750
    }
751
 
752
    /*
753
     * Second, prepare the new address space.
754
     */
1380 jermar 755
    mutex_lock_active(&new->lock);
823 jermar 756
    if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
757
        if (new->asid != ASID_INVALID)
758
            list_remove(&new->inactive_as_with_asid_link);
759
        else
760
            needs_asid = true;  /* defer call to asid_get() until new->lock is released */
761
    }
762
    SET_PTL0_ADDRESS(new->page_table);
1380 jermar 763
    mutex_unlock(&new->lock);
823 jermar 764
 
765
    if (needs_asid) {
766
        /*
767
         * Allocation of new ASID was deferred
768
         * until now in order to avoid deadlock.
769
         */
770
        asid_t asid;
771
 
772
        asid = asid_get();
1380 jermar 773
        mutex_lock_active(&new->lock);
823 jermar 774
        new->asid = asid;
1380 jermar 775
        mutex_unlock(&new->lock);
823 jermar 776
    }
777
    spinlock_unlock(&as_lock);
778
    interrupts_restore(ipl);
779
 
780
    /*
703 jermar 781
     * Perform architecture-specific steps.
727 jermar 782
     * (e.g. write ASID to hardware register etc.)
703 jermar 783
     */
823 jermar 784
    as_install_arch(new);
703 jermar 785
 
823 jermar 786
    AS = new;
703 jermar 787
}
754 jermar 788
 
1235 jermar 789
/** Convert address space area flags to page flags.
754 jermar 790
 *
1235 jermar 791
 * @param aflags Flags of some address space area.
754 jermar 792
 *
1235 jermar 793
 * @return Flags to be passed to page_mapping_insert().
754 jermar 794
 */
1235 jermar 795
int area_flags_to_page_flags(int aflags)
754 jermar 796
{
797
    int flags;
798
 
1178 jermar 799
    flags = PAGE_USER | PAGE_PRESENT;
754 jermar 800
 
1235 jermar 801
    if (aflags & AS_AREA_READ)
1026 jermar 802
        flags |= PAGE_READ;
803
 
1235 jermar 804
    if (aflags & AS_AREA_WRITE)
1026 jermar 805
        flags |= PAGE_WRITE;
806
 
1235 jermar 807
    if (aflags & AS_AREA_EXEC)
1026 jermar 808
        flags |= PAGE_EXEC;
809
 
1235 jermar 810
    if (!(aflags & AS_AREA_DEVICE))
1178 jermar 811
        flags |= PAGE_CACHEABLE;
812
 
754 jermar 813
    return flags;
814
}
756 jermar 815
 
1235 jermar 816
/** Compute flags for virtual address translation subsytem.
817
 *
818
 * The address space area must be locked.
819
 * Interrupts must be disabled.
820
 *
821
 * @param a Address space area.
822
 *
823
 * @return Flags to be used in page_mapping_insert().
824
 */
1409 jermar 825
int as_area_get_flags(as_area_t *a)
1235 jermar 826
{
827
    return area_flags_to_page_flags(a->flags);
828
}
829
 
756 jermar 830
/** Create page table.
831
 *
832
 * Depending on architecture, create either address space
833
 * private or global page table.
834
 *
835
 * @param flags Flags saying whether the page table is for kernel address space.
836
 *
837
 * @return First entry of the page table.
838
 */
839
pte_t *page_table_create(int flags)
840
{
841
        ASSERT(as_operations);
842
        ASSERT(as_operations->page_table_create);
843
 
844
        return as_operations->page_table_create(flags);
845
}
977 jermar 846
 
1044 jermar 847
/** Lock page table.
848
 *
849
 * This function should be called before any page_mapping_insert(),
850
 * page_mapping_remove() and page_mapping_find().
851
 *
852
 * Locking order is such that address space areas must be locked
853
 * prior to this call. Address space can be locked prior to this
854
 * call in which case the lock argument is false.
855
 *
856
 * @param as Address space.
1248 jermar 857
 * @param lock If false, do not attempt to lock as->lock.
1044 jermar 858
 */
859
void page_table_lock(as_t *as, bool lock)
860
{
861
    ASSERT(as_operations);
862
    ASSERT(as_operations->page_table_lock);
863
 
864
    as_operations->page_table_lock(as, lock);
865
}
866
 
867
/** Unlock page table.
868
 *
869
 * @param as Address space.
1248 jermar 870
 * @param unlock If false, do not attempt to unlock as->lock.
1044 jermar 871
 */
872
void page_table_unlock(as_t *as, bool unlock)
873
{
874
    ASSERT(as_operations);
875
    ASSERT(as_operations->page_table_unlock);
876
 
877
    as_operations->page_table_unlock(as, unlock);
878
}
879
 
977 jermar 880
 
881
/** Find address space area and lock it.
882
 *
883
 * The address space must be locked and interrupts must be disabled.
884
 *
885
 * @param as Address space.
886
 * @param va Virtual address.
887
 *
888
 * @return Locked address space area containing va on success or NULL on failure.
889
 */
890
as_area_t *find_area_and_lock(as_t *as, __address va)
891
{
892
    as_area_t *a;
1147 jermar 893
    btree_node_t *leaf, *lnode;
894
    int i;
977 jermar 895
 
1147 jermar 896
    a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf);
897
    if (a) {
898
        /* va is the base address of an address space area */
1380 jermar 899
        mutex_lock(&a->lock);
1147 jermar 900
        return a;
901
    }
902
 
903
    /*
1150 jermar 904
     * Search the leaf node and the righmost record of its left neighbour
1147 jermar 905
     * to find out whether this is a miss or va belongs to an address
906
     * space area found there.
907
     */
908
 
909
    /* First, search the leaf node itself. */
910
    for (i = 0; i < leaf->keys; i++) {
911
        a = (as_area_t *) leaf->value[i];
1380 jermar 912
        mutex_lock(&a->lock);
1147 jermar 913
        if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) {
914
            return a;
915
        }
1380 jermar 916
        mutex_unlock(&a->lock);
1147 jermar 917
    }
977 jermar 918
 
1147 jermar 919
    /*
1150 jermar 920
     * Second, locate the left neighbour and test its last record.
1148 jermar 921
     * Because of its position in the B+tree, it must have base < va.
1147 jermar 922
     */
1150 jermar 923
    if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 924
        a = (as_area_t *) lnode->value[lnode->keys - 1];
1380 jermar 925
        mutex_lock(&a->lock);
1147 jermar 926
        if (va < a->base + a->pages * PAGE_SIZE) {
1048 jermar 927
            return a;
1147 jermar 928
        }
1380 jermar 929
        mutex_unlock(&a->lock);
977 jermar 930
    }
931
 
932
    return NULL;
933
}
1048 jermar 934
 
935
/** Check area conflicts with other areas.
936
 *
937
 * The address space must be locked and interrupts must be disabled.
938
 *
939
 * @param as Address space.
940
 * @param va Starting virtual address of the area being tested.
941
 * @param size Size of the area being tested.
942
 * @param avoid_area Do not touch this area.
943
 *
944
 * @return True if there is no conflict, false otherwise.
945
 */
946
bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area)
947
{
948
    as_area_t *a;
1147 jermar 949
    btree_node_t *leaf, *node;
950
    int i;
1048 jermar 951
 
1070 jermar 952
    /*
953
     * We don't want any area to have conflicts with NULL page.
954
     */
955
    if (overlaps(va, size, NULL, PAGE_SIZE))
956
        return false;
957
 
1147 jermar 958
    /*
959
     * The leaf node is found in O(log n), where n is proportional to
960
     * the number of address space areas belonging to as.
961
     * The check for conflicts is then attempted on the rightmost
1150 jermar 962
     * record in the left neighbour, the leftmost record in the right
963
     * neighbour and all records in the leaf node itself.
1147 jermar 964
     */
1048 jermar 965
 
1147 jermar 966
    if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) {
967
        if (a != avoid_area)
968
            return false;
969
    }
970
 
971
    /* First, check the two border cases. */
1150 jermar 972
    if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 973
        a = (as_area_t *) node->value[node->keys - 1];
1380 jermar 974
        mutex_lock(&a->lock);
1147 jermar 975
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 976
            mutex_unlock(&a->lock);
1147 jermar 977
            return false;
978
        }
1380 jermar 979
        mutex_unlock(&a->lock);
1147 jermar 980
    }
1150 jermar 981
    if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) {
1147 jermar 982
        a = (as_area_t *) node->value[0];
1380 jermar 983
        mutex_lock(&a->lock);
1147 jermar 984
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 985
            mutex_unlock(&a->lock);
1147 jermar 986
            return false;
987
        }
1380 jermar 988
        mutex_unlock(&a->lock);
1147 jermar 989
    }
990
 
991
    /* Second, check the leaf node. */
992
    for (i = 0; i < leaf->keys; i++) {
993
        a = (as_area_t *) leaf->value[i];
994
 
1048 jermar 995
        if (a == avoid_area)
996
            continue;
1147 jermar 997
 
1380 jermar 998
        mutex_lock(&a->lock);
1147 jermar 999
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
1380 jermar 1000
            mutex_unlock(&a->lock);
1147 jermar 1001
            return false;
1002
        }
1380 jermar 1003
        mutex_unlock(&a->lock);
1048 jermar 1004
    }
1005
 
1070 jermar 1006
    /*
1007
     * So far, the area does not conflict with other areas.
1008
     * Check if it doesn't conflict with kernel address space.
1009
     */  
1010
    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
1011
        return !overlaps(va, size,
1012
            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START);
1013
    }
1014
 
1048 jermar 1015
    return true;
1016
}
1235 jermar 1017
 
1380 jermar 1018
/** Return size of the address space area with given base.  */
1329 palkovsky 1019
size_t as_get_size(__address base)
1020
{
1021
    ipl_t ipl;
1022
    as_area_t *src_area;
1023
    size_t size;
1024
 
1025
    ipl = interrupts_disable();
1026
    src_area = find_area_and_lock(AS, base);
1027
    if (src_area){
1028
        size = src_area->pages * PAGE_SIZE;
1380 jermar 1029
        mutex_unlock(&src_area->lock);
1329 palkovsky 1030
    } else {
1031
        size = 0;
1032
    }
1033
    interrupts_restore(ipl);
1034
    return size;
1035
}
1036
 
1387 jermar 1037
/** Mark portion of address space area as used.
1038
 *
1039
 * The address space area must be already locked.
1040
 *
1041
 * @param a Address space area.
1042
 * @param page First page to be marked.
1043
 * @param count Number of page to be marked.
1044
 *
1045
 * @return 0 on failure and 1 on success.
1046
 */
1047
int used_space_insert(as_area_t *a, __address page, count_t count)
1048
{
1049
    btree_node_t *leaf, *node;
1050
    count_t pages;
1051
    int i;
1052
 
1053
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1054
    ASSERT(count);
1055
 
1056
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1057
    if (pages) {
1058
        /*
1059
         * We hit the beginning of some used space.
1060
         */
1061
        return 0;
1062
    }
1063
 
1064
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1065
    if (node) {
1066
        __address left_pg = node->key[node->keys - 1], right_pg = leaf->key[0];
1067
        count_t left_cnt = (count_t) node->value[node->keys - 1], right_cnt = (count_t) leaf->value[0];
1068
 
1069
        /*
1070
         * Examine the possibility that the interval fits
1071
         * somewhere between the rightmost interval of
1072
         * the left neigbour and the first interval of the leaf.
1073
         */
1074
 
1075
        if (page >= right_pg) {
1076
            /* Do nothing. */
1077
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1078
            /* The interval intersects with the left interval. */
1079
            return 0;
1080
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1081
            /* The interval intersects with the right interval. */
1082
            return 0;          
1083
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1084
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1085
            node->value[node->keys - 1] += count + right_cnt;
1387 jermar 1086
            btree_remove(&a->used_space, right_pg, leaf);
1087
            return 1;
1088
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1089
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1090
            node->value[node->keys - 1] += count;
1387 jermar 1091
            return 1;
1092
        } else if (page + count*PAGE_SIZE == right_pg) {
1093
            /*
1094
             * The interval can be addded by simply moving base of the right
1095
             * interval down and increasing its size accordingly.
1096
             */
1403 jermar 1097
            leaf->value[0] += count;
1387 jermar 1098
            leaf->key[0] = page;
1099
            return 1;
1100
        } else {
1101
            /*
1102
             * The interval is between both neigbouring intervals,
1103
             * but cannot be merged with any of them.
1104
             */
1105
            btree_insert(&a->used_space, page, (void *) count, leaf);
1106
            return 1;
1107
        }
1108
    } else if (page < leaf->key[0]) {
1109
        __address right_pg = leaf->key[0];
1110
        count_t right_cnt = (count_t) leaf->value[0];
1111
 
1112
        /*
1113
         * Investigate the border case in which the left neighbour does not
1114
         * exist but the interval fits from the left.
1115
         */
1116
 
1117
        if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1118
            /* The interval intersects with the right interval. */
1119
            return 0;
1120
        } else if (page + count*PAGE_SIZE == right_pg) {
1121
            /*
1122
             * The interval can be added by moving the base of the right interval down
1123
             * and increasing its size accordingly.
1124
             */
1125
            leaf->key[0] = page;
1403 jermar 1126
            leaf->value[0] += count;
1387 jermar 1127
            return 1;
1128
        } else {
1129
            /*
1130
             * The interval doesn't adjoin with the right interval.
1131
             * It must be added individually.
1132
             */
1133
            btree_insert(&a->used_space, page, (void *) count, leaf);
1134
            return 1;
1135
        }
1136
    }
1137
 
1138
    node = btree_leaf_node_right_neighbour(&a->used_space, leaf);
1139
    if (node) {
1140
        __address left_pg = leaf->key[leaf->keys - 1], right_pg = node->key[0];
1141
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1], right_cnt = (count_t) node->value[0];
1142
 
1143
        /*
1144
         * Examine the possibility that the interval fits
1145
         * somewhere between the leftmost interval of
1146
         * the right neigbour and the last interval of the leaf.
1147
         */
1148
 
1149
        if (page < left_pg) {
1150
            /* Do nothing. */
1151
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1152
            /* The interval intersects with the left interval. */
1153
            return 0;
1154
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1155
            /* The interval intersects with the right interval. */
1156
            return 0;          
1157
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1158
            /* The interval can be added by merging the two already present intervals. */
1403 jermar 1159
            leaf->value[leaf->keys - 1] += count + right_cnt;
1387 jermar 1160
            btree_remove(&a->used_space, right_pg, node);
1161
            return 1;
1162
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1163
            /* The interval can be added by simply growing the left interval. */
1403 jermar 1164
            leaf->value[leaf->keys - 1] +=  count;
1387 jermar 1165
            return 1;
1166
        } else if (page + count*PAGE_SIZE == right_pg) {
1167
            /*
1168
             * The interval can be addded by simply moving base of the right
1169
             * interval down and increasing its size accordingly.
1170
             */
1403 jermar 1171
            node->value[0] += count;
1387 jermar 1172
            node->key[0] = page;
1173
            return 1;
1174
        } else {
1175
            /*
1176
             * The interval is between both neigbouring intervals,
1177
             * but cannot be merged with any of them.
1178
             */
1179
            btree_insert(&a->used_space, page, (void *) count, leaf);
1180
            return 1;
1181
        }
1182
    } else if (page >= leaf->key[leaf->keys - 1]) {
1183
        __address left_pg = leaf->key[leaf->keys - 1];
1184
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1185
 
1186
        /*
1187
         * Investigate the border case in which the right neighbour does not
1188
         * exist but the interval fits from the right.
1189
         */
1190
 
1191
        if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1403 jermar 1192
            /* The interval intersects with the left interval. */
1387 jermar 1193
            return 0;
1194
        } else if (left_pg + left_cnt*PAGE_SIZE == page) {
1195
            /* The interval can be added by growing the left interval. */
1403 jermar 1196
            leaf->value[leaf->keys - 1] += count;
1387 jermar 1197
            return 1;
1198
        } else {
1199
            /*
1200
             * The interval doesn't adjoin with the left interval.
1201
             * It must be added individually.
1202
             */
1203
            btree_insert(&a->used_space, page, (void *) count, leaf);
1204
            return 1;
1205
        }
1206
    }
1207
 
1208
    /*
1209
     * Note that if the algorithm made it thus far, the interval can fit only
1210
     * between two other intervals of the leaf. The two border cases were already
1211
     * resolved.
1212
     */
1213
    for (i = 1; i < leaf->keys; i++) {
1214
        if (page < leaf->key[i]) {
1215
            __address left_pg = leaf->key[i - 1], right_pg = leaf->key[i];
1216
            count_t left_cnt = (count_t) leaf->value[i - 1], right_cnt = (count_t) leaf->value[i];
1217
 
1218
            /*
1219
             * The interval fits between left_pg and right_pg.
1220
             */
1221
 
1222
            if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
1223
                /* The interval intersects with the left interval. */
1224
                return 0;
1225
            } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
1226
                /* The interval intersects with the right interval. */
1227
                return 0;          
1228
            } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
1229
                /* The interval can be added by merging the two already present intervals. */
1403 jermar 1230
                leaf->value[i - 1] += count + right_cnt;
1387 jermar 1231
                btree_remove(&a->used_space, right_pg, leaf);
1232
                return 1;
1233
            } else if (page == left_pg + left_cnt*PAGE_SIZE) {
1234
                /* The interval can be added by simply growing the left interval. */
1403 jermar 1235
                leaf->value[i - 1] += count;
1387 jermar 1236
                return 1;
1237
            } else if (page + count*PAGE_SIZE == right_pg) {
1238
                /*
1239
                     * The interval can be addded by simply moving base of the right
1240
                 * interval down and increasing its size accordingly.
1241
                 */
1403 jermar 1242
                leaf->value[i] += count;
1387 jermar 1243
                leaf->key[i] = page;
1244
                return 1;
1245
            } else {
1246
                /*
1247
                 * The interval is between both neigbouring intervals,
1248
                 * but cannot be merged with any of them.
1249
                 */
1250
                btree_insert(&a->used_space, page, (void *) count, leaf);
1251
                return 1;
1252
            }
1253
        }
1254
    }
1255
 
1256
    panic("Inconsistency detected while adding %d pages of used space at %P.\n", count, page);
1257
}
1258
 
1259
/** Mark portion of address space area as unused.
1260
 *
1261
 * The address space area must be already locked.
1262
 *
1263
 * @param a Address space area.
1264
 * @param page First page to be marked.
1265
 * @param count Number of page to be marked.
1266
 *
1267
 * @return 0 on failure and 1 on success.
1268
 */
1269
int used_space_remove(as_area_t *a, __address page, count_t count)
1270
{
1271
    btree_node_t *leaf, *node;
1272
    count_t pages;
1273
    int i;
1274
 
1275
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
1276
    ASSERT(count);
1277
 
1278
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
1279
    if (pages) {
1280
        /*
1281
         * We are lucky, page is the beginning of some interval.
1282
         */
1283
        if (count > pages) {
1284
            return 0;
1285
        } else if (count == pages) {
1286
            btree_remove(&a->used_space, page, leaf);
1403 jermar 1287
            return 1;
1387 jermar 1288
        } else {
1289
            /*
1290
             * Find the respective interval.
1291
             * Decrease its size and relocate its start address.
1292
             */
1293
            for (i = 0; i < leaf->keys; i++) {
1294
                if (leaf->key[i] == page) {
1295
                    leaf->key[i] += count*PAGE_SIZE;
1403 jermar 1296
                    leaf->value[i] -= count;
1387 jermar 1297
                    return 1;
1298
                }
1299
            }
1300
            goto error;
1301
        }
1302
    }
1303
 
1304
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
1305
    if (node && page < leaf->key[0]) {
1306
        __address left_pg = node->key[node->keys - 1];
1307
        count_t left_cnt = (count_t) node->value[node->keys - 1];
1308
 
1309
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1310
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1311
                /*
1312
                 * The interval is contained in the rightmost interval
1313
                 * of the left neighbour and can be removed by
1314
                 * updating the size of the bigger interval.
1315
                 */
1403 jermar 1316
                node->value[node->keys - 1] -= count;
1387 jermar 1317
                return 1;
1318
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1319
                count_t new_cnt;
1387 jermar 1320
 
1321
                /*
1322
                 * The interval is contained in the rightmost interval
1323
                 * of the left neighbour but its removal requires
1324
                 * both updating the size of the original interval and
1325
                 * also inserting a new interval.
1326
                 */
1403 jermar 1327
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1328
                node->value[node->keys - 1] -= count + new_cnt;
1387 jermar 1329
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1330
                return 1;
1331
            }
1332
        }
1333
        return 0;
1334
    } else if (page < leaf->key[0]) {
1335
        return 0;
1336
    }
1337
 
1338
    if (page > leaf->key[leaf->keys - 1]) {
1339
        __address left_pg = leaf->key[leaf->keys - 1];
1340
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
1341
 
1342
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1343
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1344
                /*
1345
                 * The interval is contained in the rightmost interval
1346
                 * of the leaf and can be removed by updating the size
1347
                 * of the bigger interval.
1348
                 */
1403 jermar 1349
                leaf->value[leaf->keys - 1] -= count;
1387 jermar 1350
                return 1;
1351
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1352
                count_t new_cnt;
1387 jermar 1353
 
1354
                /*
1355
                 * The interval is contained in the rightmost interval
1356
                 * of the leaf but its removal requires both updating
1357
                 * the size of the original interval and
1358
                 * also inserting a new interval.
1359
                 */
1403 jermar 1360
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1361
                leaf->value[leaf->keys - 1] -= count + new_cnt;
1387 jermar 1362
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1363
                return 1;
1364
            }
1365
        }
1366
        return 0;
1367
    }  
1368
 
1369
    /*
1370
     * The border cases have been already resolved.
1371
     * Now the interval can be only between intervals of the leaf.
1372
     */
1373
    for (i = 1; i < leaf->keys - 1; i++) {
1374
        if (page < leaf->key[i]) {
1375
            __address left_pg = leaf->key[i - 1];
1376
            count_t left_cnt = (count_t) leaf->value[i - 1];
1377
 
1378
            /*
1379
             * Now the interval is between intervals corresponding to (i - 1) and i.
1380
             */
1381
            if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
1382
                if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
1383
                    /*
1384
                    * The interval is contained in the interval (i - 1)
1385
                     * of the leaf and can be removed by updating the size
1386
                     * of the bigger interval.
1387
                     */
1403 jermar 1388
                    leaf->value[i - 1] -= count;
1387 jermar 1389
                    return 1;
1390
                } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
1403 jermar 1391
                    count_t new_cnt;
1387 jermar 1392
 
1393
                    /*
1394
                     * The interval is contained in the interval (i - 1)
1395
                     * of the leaf but its removal requires both updating
1396
                     * the size of the original interval and
1397
                     * also inserting a new interval.
1398
                     */
1403 jermar 1399
                    new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
1400
                    leaf->value[i - 1] -= count + new_cnt;
1387 jermar 1401
                    btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
1402
                    return 1;
1403
                }
1404
            }
1405
            return 0;
1406
        }
1407
    }
1408
 
1409
error:
1410
    panic("Inconsistency detected while removing %d pages of used space from %P.\n", count, page);
1411
}
1412
 
1409 jermar 1413
/** Remove reference to address space area share info.
1414
 *
1415
 * If the reference count drops to 0, the sh_info is deallocated.
1416
 *
1417
 * @param sh_info Pointer to address space area share info.
1418
 */
1419
void sh_info_remove_reference(share_info_t *sh_info)
1420
{
1421
    bool dealloc = false;
1422
 
1423
    mutex_lock(&sh_info->lock);
1424
    ASSERT(sh_info->refcount);
1425
    if (--sh_info->refcount == 0) {
1426
        dealloc = true;
1427
        bool cond;
1428
 
1429
        /*
1430
         * Now walk carefully the pagemap B+tree and free/remove
1431
         * reference from all frames found there.
1432
         */
1433
        for (cond = true; cond;) {
1434
            btree_node_t *node;
1435
 
1436
            ASSERT(!list_empty(&sh_info->pagemap.leaf_head));
1437
            node = list_get_instance(sh_info->pagemap.leaf_head.next, btree_node_t, leaf_link);
1438
            if ((cond = node->keys)) {
1439
                frame_free(ADDR2PFN((__address) node->value[0]));
1440
                btree_remove(&sh_info->pagemap, node->key[0], node);
1441
            }
1442
        }
1443
 
1444
    }
1445
    mutex_unlock(&sh_info->lock);
1446
 
1447
    if (dealloc) {
1448
        btree_destroy(&sh_info->pagemap);
1449
        free(sh_info);
1450
    }
1451
}
1452
 
1453
static int anon_page_fault(as_area_t *area, __address addr);
1454
static void anon_frame_free(as_area_t *area, __address page, __address frame);
1455
 
1235 jermar 1456
/*
1409 jermar 1457
 * Anonymous memory backend.
1458
 */
1459
mem_backend_t anon_backend = {
1460
    .backend_page_fault = anon_page_fault,
1461
    .backend_frame_free = anon_frame_free
1462
};
1463
 
1464
/** Service a page fault in the anonymous memory address space area.
1465
 *
1466
 * The address space area and page tables must be already locked.
1467
 *
1468
 * @param area Pointer to the address space area.
1469
 * @param addr Faulting virtual address.
1470
 *
1471
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
1472
 */
1473
int anon_page_fault(as_area_t *area, __address addr)
1474
{
1475
    __address frame;
1476
 
1477
    if (area->sh_info) {
1478
        btree_node_t *leaf;
1479
 
1480
        /*
1481
         * The area is shared, chances are that the mapping can be found
1482
         * in the pagemap of the address space area share info structure.
1483
         * In the case that the pagemap does not contain the respective
1484
         * mapping, a new frame is allocated and the mapping is created.
1485
         */
1486
        mutex_lock(&area->sh_info->lock);
1487
        frame = (__address) btree_search(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), &leaf);
1488
        if (!frame) {
1489
            bool allocate = true;
1490
            int i;
1491
 
1492
            /*
1493
             * Zero can be returned as a valid frame address.
1494
             * Just a small workaround.
1495
             */
1496
            for (i = 0; i < leaf->keys; i++) {
1497
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
1498
                    allocate = false;
1499
                    break;
1500
                }
1501
            }
1502
            if (allocate) {
1503
                frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1504
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
1505
 
1506
                /*
1507
                 * Insert the address of the newly allocated frame to the pagemap.
1508
                 */
1509
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), (void *) frame, leaf);
1510
            }
1511
        }
1512
        mutex_unlock(&area->sh_info->lock);
1513
    } else {
1514
 
1515
        /*
1516
         * In general, there can be several reasons that
1517
         * can have caused this fault.
1518
         *
1519
         * - non-existent mapping: the area is an anonymous
1520
         *   area (e.g. heap or stack) and so far has not been
1521
         *   allocated a frame for the faulting page
1522
         *
1523
         * - non-present mapping: another possibility,
1524
         *   currently not implemented, would be frame
1525
         *   reuse; when this becomes a possibility,
1526
         *   do not forget to distinguish between
1527
         *   the different causes
1528
         */
1529
        frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
1530
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
1531
    }
1532
 
1533
    /*
1534
     * Map 'page' to 'frame'.
1535
     * Note that TLB shootdown is not attempted as only new information is being
1536
     * inserted into page tables.
1537
     */
1538
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
1539
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
1540
        panic("Could not insert used space.\n");
1541
 
1542
    return AS_PF_OK;
1543
}
1544
 
1545
/** Free a frame that is backed by the anonymous memory backend.
1546
 *
1547
 * The address space area and page tables must be already locked.
1548
 *
1549
 * @param area Ignored.
1550
 * @param page Ignored.
1551
 * @param frame Frame to be released.
1552
 */
1553
void anon_frame_free(as_area_t *area, __address page, __address frame)
1554
{
1555
    frame_free(ADDR2PFN(frame));
1556
}
1557
 
1558
/*
1235 jermar 1559
 * Address space related syscalls.
1560
 */
1561
 
1562
/** Wrapper for as_area_create(). */
1563
__native sys_as_area_create(__address address, size_t size, int flags)
1564
{
1409 jermar 1565
    if (as_area_create(AS, flags, size, address, AS_AREA_ATTR_NONE, &anon_backend, NULL))
1235 jermar 1566
        return (__native) address;
1567
    else
1568
        return (__native) -1;
1569
}
1570
 
1571
/** Wrapper for as_area_resize. */
1572
__native sys_as_area_resize(__address address, size_t size, int flags)
1573
{
1306 jermar 1574
    return (__native) as_area_resize(AS, address, size, 0);
1235 jermar 1575
}
1576
 
1306 jermar 1577
/** Wrapper for as_area_destroy. */
1578
__native sys_as_area_destroy(__address address)
1579
{
1580
    return (__native) as_area_destroy(AS, address);
1581
}