arch/powerpc/lib/rheap.c

   1 /*
   2  * A Remote Heap.  Remote means that we don't touch the memory that the
   3  * heap points to. Normal heap implementations use the memory they manage
   4  * to place their list. We cannot do that because the memory we manage may
   5  * have special properties, for example it is uncachable or of different
   6  * endianess.
   7  *
   8  * Author: Pantelis Antoniou <panto@intracom.gr>
   9  *
  10  * 2004 (c) INTRACOM S.A. Greece. This file is licensed under
  11  * the terms of the GNU General Public License version 2. This program
  12  * is licensed "as is" without any warranty of any kind, whether express
  13  * or implied.
  14  */
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/mm.h>
  18 #include <linux/slab.h>
  19
  20 #include <asm/rheap.h>
  21
  22 /*
  23  * Fixup a list_head, needed when copying lists.  If the pointers fall
  24  * between s and e, apply the delta.  This assumes that
  25  * sizeof(struct list_head *) == sizeof(unsigned long *).
  26  */
  27 static inline void fixup(unsigned long s, unsigned long e, int d,
  28                          struct list_head *l)
  29 {
  30         unsigned long *pp;
  31
  32         pp = (unsigned long *)&l->next;
  33         if (*pp >= s && *pp < e)
  34                 *pp += d;
  35
  36         pp = (unsigned long *)&l->prev;
  37         if (*pp >= s && *pp < e)
  38                 *pp += d;
  39 }
  40
  41 /* Grow the allocated blocks */
  42 static int grow(rh_info_t * info, int max_blocks)
  43 {
  44         rh_block_t *block, *blk;
  45         int i, new_blocks;
  46         int delta;
  47         unsigned long blks, blke;
  48
  49         if (max_blocks <= info->max_blocks)
  50                 return -EINVAL;
  51
  52         new_blocks = max_blocks - info->max_blocks;
  53
  54         block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_KERNEL);
  55         if (block == NULL)
  56                 return -ENOMEM;
  57
  58         if (info->max_blocks > 0) {
  59
  60                 /* copy old block area */
  61                 memcpy(block, info->block,
  62                        sizeof(rh_block_t) * info->max_blocks);
  63
  64                 delta = (char *)block - (char *)info->block;
  65
  66                 /* and fixup list pointers */
  67                 blks = (unsigned long)info->block;
  68                 blke = (unsigned long)(info->block + info->max_blocks);
  69
  70                 for (i = 0, blk = block; i < info->max_blocks; i++, blk++)
  71                         fixup(blks, blke, delta, &blk->list);
  72
  73                 fixup(blks, blke, delta, &info->empty_list);
  74                 fixup(blks, blke, delta, &info->free_list);
  75                 fixup(blks, blke, delta, &info->taken_list);
  76
  77                 /* free the old allocated memory */
  78                 if ((info->flags & RHIF_STATIC_BLOCK) == 0)
  79                         kfree(info->block);
  80         }
  81
  82         info->block = block;
  83         info->empty_slots += new_blocks;
  84         info->max_blocks = max_blocks;
  85         info->flags &= ~RHIF_STATIC_BLOCK;
  86
  87         /* add all new blocks to the free list */
  88         for (i = 0, blk = block + info->max_blocks; i < new_blocks; i++, blk++)
  89                 list_add(&blk->list, &info->empty_list);
  90
  91         return 0;
  92 }
  93
  94 /*
  95  * Assure at least the required amount of empty slots.  If this function
  96  * causes a grow in the block area then all pointers kept to the block
  97  * area are invalid!
  98  */
  99 static int assure_empty(rh_info_t * info, int slots)
 100 {
 101         int max_blocks;
 102
 103         /* This function is not meant to be used to grow uncontrollably */
 104         if (slots >= 4)
 105                 return -EINVAL;
 106
 107         /* Enough space */
 108         if (info->empty_slots >= slots)
 109                 return 0;
 110
 111         /* Next 16 sized block */
 112         max_blocks = ((info->max_blocks + slots) + 15) & ~15;
 113
 114         return grow(info, max_blocks);
 115 }
 116
 117 static rh_block_t *get_slot(rh_info_t * info)
 118 {
 119         rh_block_t *blk;
 120
 121         /* If no more free slots, and failure to extend. */
 122         /* XXX: You should have called assure_empty before */
 123         if (info->empty_slots == 0) {
 124                 printk(KERN_ERR "rh: out of slots; crash is imminent.\n");
 125                 return NULL;
 126         }
 127
 128         /* Get empty slot to use */
 129         blk = list_entry(info->empty_list.next, rh_block_t, list);
 130         list_del_init(&blk->list);
 131         info->empty_slots--;
 132
 133         /* Initialize */
 134         blk->start = NULL;
 135         blk->size = 0;
 136         blk->owner = NULL;
 137
 138         return blk;
 139 }
 140
 141 static inline void release_slot(rh_info_t * info, rh_block_t * blk)
 142 {
 143         list_add(&blk->list, &info->empty_list);
 144         info->empty_slots++;
 145 }
 146
 147 static void attach_free_block(rh_info_t * info, rh_block_t * blkn)
 148 {
 149         rh_block_t *blk;
 150         rh_block_t *before;
 151         rh_block_t *after;
 152         rh_block_t *next;
 153         int size;
 154         unsigned long s, e, bs, be;
 155         struct list_head *l;
 156
 157         /* We assume that they are aligned properly */
 158         size = blkn->size;
 159         s = (unsigned long)blkn->start;
 160         e = s + size;
 161
 162         /* Find the blocks immediately before and after the given one
 163          * (if any) */
 164         before = NULL;
 165         after = NULL;
 166         next = NULL;
 167
 168         list_for_each(l, &info->free_list) {
 169                 blk = list_entry(l, rh_block_t, list);
 170
 171                 bs = (unsigned long)blk->start;
 172                 be = bs + blk->size;
 173
 174                 if (next == NULL && s >= bs)
 175                         next = blk;
 176
 177                 if (be == s)
 178                         before = blk;
 179
 180                 if (e == bs)
 181                         after = blk;
 182
 183                 /* If both are not null, break now */
 184                 if (before != NULL && after != NULL)
 185                         break;
 186         }
 187
 188         /* Now check if they are really adjacent */
 189         if (before != NULL && s != (unsigned long)before->start + before->size)
 190                 before = NULL;
 191
 192         if (after != NULL && e != (unsigned long)after->start)
 193                 after = NULL;
 194
 195         /* No coalescing; list insert and return */
 196         if (before == NULL && after == NULL) {
 197
 198                 if (next != NULL)
 199                         list_add(&blkn->list, &next->list);
 200                 else
 201                         list_add(&blkn->list, &info->free_list);
 202
 203                 return;
 204         }
 205
 206         /* We don't need it anymore */
 207         release_slot(info, blkn);
 208
 209         /* Grow the before block */
 210         if (before != NULL && after == NULL) {
 211                 before->size += size;
 212                 return;
 213         }
 214
 215         /* Grow the after block backwards */
 216         if (before == NULL && after != NULL) {
 217                 after->start = (int8_t *)after->start - size;
 218                 after->size += size;
 219                 return;
 220         }
 221
 222         /* Grow the before block, and release the after block */
 223         before->size += size + after->size;
 224         list_del(&after->list);
 225         release_slot(info, after);
 226 }
 227
 228 static void attach_taken_block(rh_info_t * info, rh_block_t * blkn)
 229 {
 230         rh_block_t *blk;
 231         struct list_head *l;
 232
 233         /* Find the block immediately before the given one (if any) */
 234         list_for_each(l, &info->taken_list) {
 235                 blk = list_entry(l, rh_block_t, list);
 236                 if (blk->start > blkn->start) {
 237                         list_add_tail(&blkn->list, &blk->list);
 238                         return;
 239                 }
 240         }
 241
 242         list_add_tail(&blkn->list, &info->taken_list);
 243 }
 244
 245 /*
 246  * Create a remote heap dynamically.  Note that no memory for the blocks
 247  * are allocated.  It will upon the first allocation
 248  */
 249 rh_info_t *rh_create(unsigned int alignment)
 250 {
 251         rh_info_t *info;
 252
 253         /* Alignment must be a power of two */
 254         if ((alignment & (alignment - 1)) != 0)
 255                 return ERR_PTR(-EINVAL);
 256
 257         info = kmalloc(sizeof(*info), GFP_KERNEL);
 258         if (info == NULL)
 259                 return ERR_PTR(-ENOMEM);
 260
 261         info->alignment = alignment;
 262
 263         /* Initially everything as empty */
 264         info->block = NULL;
 265         info->max_blocks = 0;
 266         info->empty_slots = 0;
 267         info->flags = 0;
 268
 269         INIT_LIST_HEAD(&info->empty_list);
 270         INIT_LIST_HEAD(&info->free_list);
 271         INIT_LIST_HEAD(&info->taken_list);
 272
 273         return info;
 274 }
 275
 276 /*
 277  * Destroy a dynamically created remote heap.  Deallocate only if the areas
 278  * are not static
 279  */
 280 void rh_destroy(rh_info_t * info)
 281 {
 282         if ((info->flags & RHIF_STATIC_BLOCK) == 0 && info->block != NULL)
 283                 kfree(info->block);
 284
 285         if ((info->flags & RHIF_STATIC_INFO) == 0)
 286                 kfree(info);
 287 }
 288
 289 /*
 290  * Initialize in place a remote heap info block.  This is needed to support
 291  * operation very early in the startup of the kernel, when it is not yet safe
 292  * to call kmalloc.
 293  */
 294 void rh_init(rh_info_t * info, unsigned int alignment, int max_blocks,
 295              rh_block_t * block)
 296 {
 297         int i;
 298         rh_block_t *blk;
 299
 300         /* Alignment must be a power of two */
 301         if ((alignment & (alignment - 1)) != 0)
 302                 return;
 303
 304         info->alignment = alignment;
 305
 306         /* Initially everything as empty */
 307         info->block = block;
 308         info->max_blocks = max_blocks;
 309         info->empty_slots = max_blocks;
 310         info->flags = RHIF_STATIC_INFO | RHIF_STATIC_BLOCK;
 311
 312         INIT_LIST_HEAD(&info->empty_list);
 313         INIT_LIST_HEAD(&info->free_list);
 314         INIT_LIST_HEAD(&info->taken_list);
 315
 316         /* Add all new blocks to the free list */
 317         for (i = 0, blk = block; i < max_blocks; i++, blk++)
 318                 list_add(&blk->list, &info->empty_list);
 319 }
 320
 321 /* Attach a free memory region, coalesces regions if adjuscent */
 322 int rh_attach_region(rh_info_t * info, void *start, int size)
 323 {
 324         rh_block_t *blk;
 325         unsigned long s, e, m;
 326         int r;
 327
 328         /* The region must be aligned */
 329         s = (unsigned long)start;
 330         e = s + size;
 331         m = info->alignment - 1;
 332
 333         /* Round start up */
 334         s = (s + m) & ~m;
 335
 336         /* Round end down */
 337         e = e & ~m;
 338
 339         /* Take final values */
 340         start = (void *)s;
 341         size = (int)(e - s);
 342
 343         /* Grow the blocks, if needed */
 344         r = assure_empty(info, 1);
 345         if (r < 0)
 346                 return r;
 347
 348         blk = get_slot(info);
 349         blk->start = start;
 350         blk->size = size;
 351         blk->owner = NULL;
 352
 353         attach_free_block(info, blk);
 354
 355         return 0;
 356 }
 357
 358 /* Detatch given address range, splits free block if needed. */
 359 void *rh_detach_region(rh_info_t * info, void *start, int size)
 360 {
 361         struct list_head *l;
 362         rh_block_t *blk, *newblk;
 363         unsigned long s, e, m, bs, be;
 364
 365         /* Validate size */
 366         if (size <= 0)
 367                 return ERR_PTR(-EINVAL);
 368
 369         /* The region must be aligned */
 370         s = (unsigned long)start;
 371         e = s + size;
 372         m = info->alignment - 1;
 373
 374         /* Round start up */
 375         s = (s + m) & ~m;
 376
 377         /* Round end down */
 378         e = e & ~m;
 379
 380         if (assure_empty(info, 1) < 0)
 381                 return ERR_PTR(-ENOMEM);
 382
 383         blk = NULL;
 384         list_for_each(l, &info->free_list) {
 385                 blk = list_entry(l, rh_block_t, list);
 386                 /* The range must lie entirely inside one free block */
 387                 bs = (unsigned long)blk->start;
 388                 be = (unsigned long)blk->start + blk->size;
 389                 if (s >= bs && e <= be)
 390                         break;
 391                 blk = NULL;
 392         }
 393
 394         if (blk == NULL)
 395                 return ERR_PTR(-ENOMEM);
 396
 397         /* Perfect fit */
 398         if (bs == s && be == e) {
 399                 /* Delete from free list, release slot */
 400                 list_del(&blk->list);
 401                 release_slot(info, blk);
 402                 return (void *)s;
 403         }
 404
 405         /* blk still in free list, with updated start and/or size */
 406         if (bs == s || be == e) {
 407                 if (bs == s)
 408                         blk->start = (int8_t *)blk->start + size;
 409                 blk->size -= size;
 410
 411         } else {
 412                 /* The front free fragment */
 413                 blk->size = s - bs;
 414
 415                 /* the back free fragment */
 416                 newblk = get_slot(info);
 417                 newblk->start = (void *)e;
 418                 newblk->size = be - e;
 419
 420                 list_add(&newblk->list, &blk->list);
 421         }
 422
 423         return (void *)s;
 424 }
 425
 426 void *rh_alloc(rh_info_t * info, int size, const char *owner)
 427 {
 428         struct list_head *l;
 429         rh_block_t *blk;
 430         rh_block_t *newblk;
 431         void *start;
 432
 433         /* Validate size */
 434         if (size <= 0)
 435                 return ERR_PTR(-EINVAL);
 436
 437         /* Align to configured alignment */
 438         size = (size + (info->alignment - 1)) & ~(info->alignment - 1);
 439
 440         if (assure_empty(info, 1) < 0)
 441                 return ERR_PTR(-ENOMEM);
 442
 443         blk = NULL;
 444         list_for_each(l, &info->free_list) {
 445                 blk = list_entry(l, rh_block_t, list);
 446                 if (size <= blk->size)
 447                         break;
 448                 blk = NULL;
 449         }
 450
 451         if (blk == NULL)
 452                 return ERR_PTR(-ENOMEM);
 453
 454         /* Just fits */
 455         if (blk->size == size) {
 456                 /* Move from free list to taken list */
 457                 list_del(&blk->list);
 458                 blk->owner = owner;
 459                 start = blk->start;
 460
 461                 attach_taken_block(info, blk);
 462
 463                 return start;
 464         }
 465
 466         newblk = get_slot(info);
 467         newblk->start = blk->start;
 468         newblk->size = size;
 469         newblk->owner = owner;
 470
 471         /* blk still in free list, with updated start, size */
 472         blk->start = (int8_t *)blk->start + size;
 473         blk->size -= size;
 474
 475         start = newblk->start;
 476
 477         attach_taken_block(info, newblk);
 478
 479         return start;
 480 }
 481
 482 /* allocate at precisely the given address */
 483 void *rh_alloc_fixed(rh_info_t * info, void *start, int size, const char *owner)
 484 {
 485         struct list_head *l;
 486         rh_block_t *blk, *newblk1, *newblk2;
 487         unsigned long s, e, m, bs, be;
 488
 489         /* Validate size */
 490         if (size <= 0)
 491                 return ERR_PTR(-EINVAL);
 492
 493         /* The region must be aligned */
 494         s = (unsigned long)start;
 495         e = s + size;
 496         m = info->alignment - 1;
 497
 498         /* Round start up */
 499         s = (s + m) & ~m;
 500
 501         /* Round end down */
 502         e = e & ~m;
 503
 504         if (assure_empty(info, 2) < 0)
 505                 return ERR_PTR(-ENOMEM);
 506
 507         blk = NULL;
 508         list_for_each(l, &info->free_list) {
 509                 blk = list_entry(l, rh_block_t, list);
 510                 /* The range must lie entirely inside one free block */
 511                 bs = (unsigned long)blk->start;
 512                 be = (unsigned long)blk->start + blk->size;
 513                 if (s >= bs && e <= be)
 514                         break;
 515         }
 516
 517         if (blk == NULL)
 518                 return ERR_PTR(-ENOMEM);
 519
 520         /* Perfect fit */
 521         if (bs == s && be == e) {
 522                 /* Move from free list to taken list */
 523                 list_del(&blk->list);
 524                 blk->owner = owner;
 525
 526                 start = blk->start;
 527                 attach_taken_block(info, blk);
 528
 529                 return start;
 530
 531         }
 532
 533         /* blk still in free list, with updated start and/or size */
 534         if (bs == s || be == e) {
 535                 if (bs == s)
 536                         blk->start = (int8_t *)blk->start + size;
 537                 blk->size -= size;
 538
 539         } else {
 540                 /* The front free fragment */
 541                 blk->size = s - bs;
 542
 543                 /* The back free fragment */
 544                 newblk2 = get_slot(info);
 545                 newblk2->start = (void *)e;
 546                 newblk2->size = be - e;
 547
 548                 list_add(&newblk2->list, &blk->list);
 549         }
 550
 551         newblk1 = get_slot(info);
 552         newblk1->start = (void *)s;
 553         newblk1->size = e - s;
 554         newblk1->owner = owner;
 555
 556         start = newblk1->start;
 557         attach_taken_block(info, newblk1);
 558
 559         return start;
 560 }
 561
 562 int rh_free(rh_info_t * info, void *start)
 563 {
 564         rh_block_t *blk, *blk2;
 565         struct list_head *l;
 566         int size;
 567
 568         /* Linear search for block */
 569         blk = NULL;
 570         list_for_each(l, &info->taken_list) {
 571                 blk2 = list_entry(l, rh_block_t, list);
 572                 if (start < blk2->start)
 573                         break;
 574                 blk = blk2;
 575         }
 576
 577         if (blk == NULL || start > (blk->start + blk->size))
 578                 return -EINVAL;
 579
 580         /* Remove from taken list */
 581         list_del(&blk->list);
 582
 583         /* Get size of freed block */
 584         size = blk->size;
 585         attach_free_block(info, blk);
 586
 587         return size;
 588 }
 589
 590 int rh_get_stats(rh_info_t * info, int what, int max_stats, rh_stats_t * stats)
 591 {
 592         rh_block_t *blk;
 593         struct list_head *l;
 594         struct list_head *h;
 595         int nr;
 596
 597         switch (what) {
 598
 599         case RHGS_FREE:
 600                 h = &info->free_list;
 601                 break;
 602
 603         case RHGS_TAKEN:
 604                 h = &info->taken_list;
 605                 break;
 606
 607         default:
 608                 return -EINVAL;
 609         }
 610
 611         /* Linear search for block */
 612         nr = 0;
 613         list_for_each(l, h) {
 614                 blk = list_entry(l, rh_block_t, list);
 615                 if (stats != NULL && nr < max_stats) {
 616                         stats->start = blk->start;
 617                         stats->size = blk->size;
 618                         stats->owner = blk->owner;
 619                         stats++;
 620                 }
 621                 nr++;
 622         }
 623
 624         return nr;
 625 }
 626
 627 int rh_set_owner(rh_info_t * info, void *start, const char *owner)
 628 {
 629         rh_block_t *blk, *blk2;
 630         struct list_head *l;
 631         int size;
 632
 633         /* Linear search for block */
 634         blk = NULL;
 635         list_for_each(l, &info->taken_list) {
 636                 blk2 = list_entry(l, rh_block_t, list);
 637                 if (start < blk2->start)
 638                         break;
 639                 blk = blk2;
 640         }
 641
 642         if (blk == NULL || start > (blk->start + blk->size))
 643                 return -EINVAL;
 644
 645         blk->owner = owner;
 646         size = blk->size;
 647
 648         return size;
 649 }
 650
 651 void rh_dump(rh_info_t * info)
 652 {
 653         static rh_stats_t st[32];       /* XXX maximum 32 blocks */
 654         int maxnr;
 655         int i, nr;
 656
 657         maxnr = sizeof(st) / sizeof(st[0]);
 658
 659         printk(KERN_INFO
 660                "info @0x%p (%d slots empty / %d max)\n",
 661                info, info->empty_slots, info->max_blocks);
 662
 663         printk(KERN_INFO "  Free:\n");
 664         nr = rh_get_stats(info, RHGS_FREE, maxnr, st);
 665         if (nr > maxnr)
 666                 nr = maxnr;
 667         for (i = 0; i < nr; i++)
 668                 printk(KERN_INFO
 669                        "    0x%p-0x%p (%u)\n",
 670                        st[i].start, (int8_t *) st[i].start + st[i].size,
 671                        st[i].size);
 672         printk(KERN_INFO "\n");
 673
 674         printk(KERN_INFO "  Taken:\n");
 675         nr = rh_get_stats(info, RHGS_TAKEN, maxnr, st);
 676         if (nr > maxnr)
 677                 nr = maxnr;
 678         for (i = 0; i < nr; i++)
 679                 printk(KERN_INFO
 680                        "    0x%p-0x%p (%u) %s\n",
 681                        st[i].start, (int8_t *) st[i].start + st[i].size,
 682                        st[i].size, st[i].owner != NULL ? st[i].owner : "");
 683         printk(KERN_INFO "\n");
 684 }
 685
 686 void rh_dump_blk(rh_info_t * info, rh_block_t * blk)
 687 {
 688         printk(KERN_INFO
 689                "blk @0x%p: 0x%p-0x%p (%u)\n",
 690                blk, blk->start, (int8_t *) blk->start + blk->size, blk->size);
 691 }