arch/ppc/lib/rheap.c

   1 /*
   2  * arch/ppc/syslib/rheap.c
   3  *
   4  * A Remote Heap.  Remote means that we don't touch the memory that the
   5  * heap points to. Normal heap implementations use the memory they manage
   6  * to place their list. We cannot do that because the memory we manage may
   7  * have special properties, for example it is uncachable or of different
   8  * endianess.
   9  *
  10  * Author: Pantelis Antoniou <panto@intracom.gr>
  11  *
  12  * 2004 (c) INTRACOM S.A. Greece. This file is licensed under
  13  * the terms of the GNU General Public License version 2. This program
  14  * is licensed "as is" without any warranty of any kind, whether express
  15  * or implied.
  16  */
  17 #include <linux/types.h>
  18 #include <linux/errno.h>
  19 #include <linux/mm.h>
  20 #include <linux/slab.h>
  21
  22 #include <asm/rheap.h>
  23
  24 /*
  25  * Fixup a list_head, needed when copying lists.  If the pointers fall
  26  * between s and e, apply the delta.  This assumes that
  27  * sizeof(struct list_head *) == sizeof(unsigned long *).
  28  */
  29 static inline void fixup(unsigned long s, unsigned long e, int d,
  30                          struct list_head *l)
  31 {
  32         unsigned long *pp;
  33
  34         pp = (unsigned long *)&l->next;
  35         if (*pp >= s && *pp < e)
  36                 *pp += d;
  37
  38         pp = (unsigned long *)&l->prev;
  39         if (*pp >= s && *pp < e)
  40                 *pp += d;
  41 }
  42
  43 /* Grow the allocated blocks */
  44 static int grow(rh_info_t * info, int max_blocks)
  45 {
  46         rh_block_t *block, *blk;
  47         int i, new_blocks;
  48         int delta;
  49         unsigned long blks, blke;
  50
  51         if (max_blocks <= info->max_blocks)
  52                 return -EINVAL;
  53
  54         new_blocks = max_blocks - info->max_blocks;
  55
  56         block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_KERNEL);
  57         if (block == NULL)
  58                 return -ENOMEM;
  59
  60         if (info->max_blocks > 0) {
  61
  62                 /* copy old block area */
  63                 memcpy(block, info->block,
  64                        sizeof(rh_block_t) * info->max_blocks);
  65
  66                 delta = (char *)block - (char *)info->block;
  67
  68                 /* and fixup list pointers */
  69                 blks = (unsigned long)info->block;
  70                 blke = (unsigned long)(info->block + info->max_blocks);
  71
  72                 for (i = 0, blk = block; i < info->max_blocks; i++, blk++)
  73                         fixup(blks, blke, delta, &blk->list);
  74
  75                 fixup(blks, blke, delta, &info->empty_list);
  76                 fixup(blks, blke, delta, &info->free_list);
  77                 fixup(blks, blke, delta, &info->taken_list);
  78
  79                 /* free the old allocated memory */
  80                 if ((info->flags & RHIF_STATIC_BLOCK) == 0)
  81                         kfree(info->block);
  82         }
  83
  84         info->block = block;
  85         info->empty_slots += new_blocks;
  86         info->max_blocks = max_blocks;
  87         info->flags &= ~RHIF_STATIC_BLOCK;
  88
  89         /* add all new blocks to the free list */
  90         for (i = 0, blk = block + info->max_blocks; i < new_blocks; i++, blk++)
  91                 list_add(&blk->list, &info->empty_list);
  92
  93         return 0;
  94 }
  95
  96 /*
  97  * Assure at least the required amount of empty slots.  If this function
  98  * causes a grow in the block area then all pointers kept to the block
  99  * area are invalid!
 100  */
 101 static int assure_empty(rh_info_t * info, int slots)
 102 {
 103         int max_blocks;
 104
 105         /* This function is not meant to be used to grow uncontrollably */
 106         if (slots >= 4)
 107                 return -EINVAL;
 108
 109         /* Enough space */
 110         if (info->empty_slots >= slots)
 111                 return 0;
 112
 113         /* Next 16 sized block */
 114         max_blocks = ((info->max_blocks + slots) + 15) & ~15;
 115
 116         return grow(info, max_blocks);
 117 }
 118
 119 static rh_block_t *get_slot(rh_info_t * info)
 120 {
 121         rh_block_t *blk;
 122
 123         /* If no more free slots, and failure to extend. */
 124         /* XXX: You should have called assure_empty before */
 125         if (info->empty_slots == 0) {
 126                 printk(KERN_ERR "rh: out of slots; crash is imminent.\n");
 127                 return NULL;
 128         }
 129
 130         /* Get empty slot to use */
 131         blk = list_entry(info->empty_list.next, rh_block_t, list);
 132         list_del_init(&blk->list);
 133         info->empty_slots--;
 134
 135         /* Initialize */
 136         blk->start = NULL;
 137         blk->size = 0;
 138         blk->owner = NULL;
 139
 140         return blk;
 141 }
 142
 143 static inline void release_slot(rh_info_t * info, rh_block_t * blk)
 144 {
 145         list_add(&blk->list, &info->empty_list);
 146         info->empty_slots++;
 147 }
 148
 149 static void attach_free_block(rh_info_t * info, rh_block_t * blkn)
 150 {
 151         rh_block_t *blk;
 152         rh_block_t *before;
 153         rh_block_t *after;
 154         rh_block_t *next;
 155         int size;
 156         unsigned long s, e, bs, be;
 157         struct list_head *l;
 158
 159         /* We assume that they are aligned properly */
 160         size = blkn->size;
 161         s = (unsigned long)blkn->start;
 162         e = s + size;
 163
 164         /* Find the blocks immediately before and after the given one
 165          * (if any) */
 166         before = NULL;
 167         after = NULL;
 168         next = NULL;
 169
 170         list_for_each(l, &info->free_list) {
 171                 blk = list_entry(l, rh_block_t, list);
 172
 173                 bs = (unsigned long)blk->start;
 174                 be = bs + blk->size;
 175
 176                 if (next == NULL && s >= bs)
 177                         next = blk;
 178
 179                 if (be == s)
 180                         before = blk;
 181
 182                 if (e == bs)
 183                         after = blk;
 184
 185                 /* If both are not null, break now */
 186                 if (before != NULL && after != NULL)
 187                         break;
 188         }
 189
 190         /* Now check if they are really adjacent */
 191         if (before != NULL && s != (unsigned long)before->start + before->size)
 192                 before = NULL;
 193
 194         if (after != NULL && e != (unsigned long)after->start)
 195                 after = NULL;
 196
 197         /* No coalescing; list insert and return */
 198         if (before == NULL && after == NULL) {
 199
 200                 if (next != NULL)
 201                         list_add(&blkn->list, &next->list);
 202                 else
 203                         list_add(&blkn->list, &info->free_list);
 204
 205                 return;
 206         }
 207
 208         /* We don't need it anymore */
 209         release_slot(info, blkn);
 210
 211         /* Grow the before block */
 212         if (before != NULL && after == NULL) {
 213                 before->size += size;
 214                 return;
 215         }
 216
 217         /* Grow the after block backwards */
 218         if (before == NULL && after != NULL) {
 219                 after->start = (int8_t *)after->start - size;
 220                 after->size += size;
 221                 return;
 222         }
 223
 224         /* Grow the before block, and release the after block */
 225         before->size += size + after->size;
 226         list_del(&after->list);
 227         release_slot(info, after);
 228 }
 229
 230 static void attach_taken_block(rh_info_t * info, rh_block_t * blkn)
 231 {
 232         rh_block_t *blk;
 233         struct list_head *l;
 234
 235         /* Find the block immediately before the given one (if any) */
 236         list_for_each(l, &info->taken_list) {
 237                 blk = list_entry(l, rh_block_t, list);
 238                 if (blk->start > blkn->start) {
 239                         list_add_tail(&blkn->list, &blk->list);
 240                         return;
 241                 }
 242         }
 243
 244         list_add_tail(&blkn->list, &info->taken_list);
 245 }
 246
 247 /*
 248  * Create a remote heap dynamically.  Note that no memory for the blocks
 249  * are allocated.  It will upon the first allocation
 250  */
 251 rh_info_t *rh_create(unsigned int alignment)
 252 {
 253         rh_info_t *info;
 254
 255         /* Alignment must be a power of two */
 256         if ((alignment & (alignment - 1)) != 0)
 257                 return ERR_PTR(-EINVAL);
 258
 259         info = kmalloc(sizeof(*info), GFP_KERNEL);
 260         if (info == NULL)
 261                 return ERR_PTR(-ENOMEM);
 262
 263         info->alignment = alignment;
 264
 265         /* Initially everything as empty */
 266         info->block = NULL;
 267         info->max_blocks = 0;
 268         info->empty_slots = 0;
 269         info->flags = 0;
 270
 271         INIT_LIST_HEAD(&info->empty_list);
 272         INIT_LIST_HEAD(&info->free_list);
 273         INIT_LIST_HEAD(&info->taken_list);
 274
 275         return info;
 276 }
 277
 278 /*
 279  * Destroy a dynamically created remote heap.  Deallocate only if the areas
 280  * are not static
 281  */
 282 void rh_destroy(rh_info_t * info)
 283 {
 284         if ((info->flags & RHIF_STATIC_BLOCK) == 0 && info->block != NULL)
 285                 kfree(info->block);
 286
 287         if ((info->flags & RHIF_STATIC_INFO) == 0)
 288                 kfree(info);
 289 }
 290
 291 /*
 292  * Initialize in place a remote heap info block.  This is needed to support
 293  * operation very early in the startup of the kernel, when it is not yet safe
 294  * to call kmalloc.
 295  */
 296 void rh_init(rh_info_t * info, unsigned int alignment, int max_blocks,
 297              rh_block_t * block)
 298 {
 299         int i;
 300         rh_block_t *blk;
 301
 302         /* Alignment must be a power of two */
 303         if ((alignment & (alignment - 1)) != 0)
 304                 return;
 305
 306         info->alignment = alignment;
 307
 308         /* Initially everything as empty */
 309         info->block = block;
 310         info->max_blocks = max_blocks;
 311         info->empty_slots = max_blocks;
 312         info->flags = RHIF_STATIC_INFO | RHIF_STATIC_BLOCK;
 313
 314         INIT_LIST_HEAD(&info->empty_list);
 315         INIT_LIST_HEAD(&info->free_list);
 316         INIT_LIST_HEAD(&info->taken_list);
 317
 318         /* Add all new blocks to the free list */
 319         for (i = 0, blk = block; i < max_blocks; i++, blk++)
 320                 list_add(&blk->list, &info->empty_list);
 321 }
 322
 323 /* Attach a free memory region, coalesces regions if adjuscent */
 324 int rh_attach_region(rh_info_t * info, void *start, int size)
 325 {
 326         rh_block_t *blk;
 327         unsigned long s, e, m;
 328         int r;
 329
 330         /* The region must be aligned */
 331         s = (unsigned long)start;
 332         e = s + size;
 333         m = info->alignment - 1;
 334
 335         /* Round start up */
 336         s = (s + m) & ~m;
 337
 338         /* Round end down */
 339         e = e & ~m;
 340
 341         /* Take final values */
 342         start = (void *)s;
 343         size = (int)(e - s);
 344
 345         /* Grow the blocks, if needed */
 346         r = assure_empty(info, 1);
 347         if (r < 0)
 348                 return r;
 349
 350         blk = get_slot(info);
 351         blk->start = start;
 352         blk->size = size;
 353         blk->owner = NULL;
 354
 355         attach_free_block(info, blk);
 356
 357         return 0;
 358 }
 359
 360 /* Detatch given address range, splits free block if needed. */
 361 void *rh_detach_region(rh_info_t * info, void *start, int size)
 362 {
 363         struct list_head *l;
 364         rh_block_t *blk, *newblk;
 365         unsigned long s, e, m, bs, be;
 366
 367         /* Validate size */
 368         if (size <= 0)
 369                 return ERR_PTR(-EINVAL);
 370
 371         /* The region must be aligned */
 372         s = (unsigned long)start;
 373         e = s + size;
 374         m = info->alignment - 1;
 375
 376         /* Round start up */
 377         s = (s + m) & ~m;
 378
 379         /* Round end down */
 380         e = e & ~m;
 381
 382         if (assure_empty(info, 1) < 0)
 383                 return ERR_PTR(-ENOMEM);
 384
 385         blk = NULL;
 386         list_for_each(l, &info->free_list) {
 387                 blk = list_entry(l, rh_block_t, list);
 388                 /* The range must lie entirely inside one free block */
 389                 bs = (unsigned long)blk->start;
 390                 be = (unsigned long)blk->start + blk->size;
 391                 if (s >= bs && e <= be)
 392                         break;
 393                 blk = NULL;
 394         }
 395
 396         if (blk == NULL)
 397                 return ERR_PTR(-ENOMEM);
 398
 399         /* Perfect fit */
 400         if (bs == s && be == e) {
 401                 /* Delete from free list, release slot */
 402                 list_del(&blk->list);
 403                 release_slot(info, blk);
 404                 return (void *)s;
 405         }
 406
 407         /* blk still in free list, with updated start and/or size */
 408         if (bs == s || be == e) {
 409                 if (bs == s)
 410                         blk->start = (int8_t *)blk->start + size;
 411                 blk->size -= size;
 412
 413         } else {
 414                 /* The front free fragment */
 415                 blk->size = s - bs;
 416
 417                 /* the back free fragment */
 418                 newblk = get_slot(info);
 419                 newblk->start = (void *)e;
 420                 newblk->size = be - e;
 421
 422                 list_add(&newblk->list, &blk->list);
 423         }
 424
 425         return (void *)s;
 426 }
 427
 428 void *rh_alloc(rh_info_t * info, int size, const char *owner)
 429 {
 430         struct list_head *l;
 431         rh_block_t *blk;
 432         rh_block_t *newblk;
 433         void *start;
 434
 435         /* Validate size */
 436         if (size <= 0)
 437                 return ERR_PTR(-EINVAL);
 438
 439         /* Align to configured alignment */
 440         size = (size + (info->alignment - 1)) & ~(info->alignment - 1);
 441
 442         if (assure_empty(info, 1) < 0)
 443                 return ERR_PTR(-ENOMEM);
 444
 445         blk = NULL;
 446         list_for_each(l, &info->free_list) {
 447                 blk = list_entry(l, rh_block_t, list);
 448                 if (size <= blk->size)
 449                         break;
 450                 blk = NULL;
 451         }
 452
 453         if (blk == NULL)
 454                 return ERR_PTR(-ENOMEM);
 455
 456         /* Just fits */
 457         if (blk->size == size) {
 458                 /* Move from free list to taken list */
 459                 list_del(&blk->list);
 460                 blk->owner = owner;
 461                 start = blk->start;
 462
 463                 attach_taken_block(info, blk);
 464
 465                 return start;
 466         }
 467
 468         newblk = get_slot(info);
 469         newblk->start = blk->start;
 470         newblk->size = size;
 471         newblk->owner = owner;
 472
 473         /* blk still in free list, with updated start, size */
 474         blk->start = (int8_t *)blk->start + size;
 475         blk->size -= size;
 476
 477         start = newblk->start;
 478
 479         attach_taken_block(info, newblk);
 480
 481         return start;
 482 }
 483
 484 /* allocate at precisely the given address */
 485 void *rh_alloc_fixed(rh_info_t * info, void *start, int size, const char *owner)
 486 {
 487         struct list_head *l;
 488         rh_block_t *blk, *newblk1, *newblk2;
 489         unsigned long s, e, m, bs, be;
 490
 491         /* Validate size */
 492         if (size <= 0)
 493                 return ERR_PTR(-EINVAL);
 494
 495         /* The region must be aligned */
 496         s = (unsigned long)start;
 497         e = s + size;
 498         m = info->alignment - 1;
 499
 500         /* Round start up */
 501         s = (s + m) & ~m;
 502
 503         /* Round end down */
 504         e = e & ~m;
 505
 506         if (assure_empty(info, 2) < 0)
 507                 return ERR_PTR(-ENOMEM);
 508
 509         blk = NULL;
 510         list_for_each(l, &info->free_list) {
 511                 blk = list_entry(l, rh_block_t, list);
 512                 /* The range must lie entirely inside one free block */
 513                 bs = (unsigned long)blk->start;
 514                 be = (unsigned long)blk->start + blk->size;
 515                 if (s >= bs && e <= be)
 516                         break;
 517         }
 518
 519         if (blk == NULL)
 520                 return ERR_PTR(-ENOMEM);
 521
 522         /* Perfect fit */
 523         if (bs == s && be == e) {
 524                 /* Move from free list to taken list */
 525                 list_del(&blk->list);
 526                 blk->owner = owner;
 527
 528                 start = blk->start;
 529                 attach_taken_block(info, blk);
 530
 531                 return start;
 532
 533         }
 534
 535         /* blk still in free list, with updated start and/or size */
 536         if (bs == s || be == e) {
 537                 if (bs == s)
 538                         blk->start = (int8_t *)blk->start + size;
 539                 blk->size -= size;
 540
 541         } else {
 542                 /* The front free fragment */
 543                 blk->size = s - bs;
 544
 545                 /* The back free fragment */
 546                 newblk2 = get_slot(info);
 547                 newblk2->start = (void *)e;
 548                 newblk2->size = be - e;
 549
 550                 list_add(&newblk2->list, &blk->list);
 551         }
 552
 553         newblk1 = get_slot(info);
 554         newblk1->start = (void *)s;
 555         newblk1->size = e - s;
 556         newblk1->owner = owner;
 557
 558         start = newblk1->start;
 559         attach_taken_block(info, newblk1);
 560
 561         return start;
 562 }
 563
 564 int rh_free(rh_info_t * info, void *start)
 565 {
 566         rh_block_t *blk, *blk2;
 567         struct list_head *l;
 568         int size;
 569
 570         /* Linear search for block */
 571         blk = NULL;
 572         list_for_each(l, &info->taken_list) {
 573                 blk2 = list_entry(l, rh_block_t, list);
 574                 if (start < blk2->start)
 575                         break;
 576                 blk = blk2;
 577         }
 578
 579         if (blk == NULL || start > (blk->start + blk->size))
 580                 return -EINVAL;
 581
 582         /* Remove from taken list */
 583         list_del(&blk->list);
 584
 585         /* Get size of freed block */
 586         size = blk->size;
 587         attach_free_block(info, blk);
 588
 589         return size;
 590 }
 591
 592 int rh_get_stats(rh_info_t * info, int what, int max_stats, rh_stats_t * stats)
 593 {
 594         rh_block_t *blk;
 595         struct list_head *l;
 596         struct list_head *h;
 597         int nr;
 598
 599         switch (what) {
 600
 601         case RHGS_FREE:
 602                 h = &info->free_list;
 603                 break;
 604
 605         case RHGS_TAKEN:
 606                 h = &info->taken_list;
 607                 break;
 608
 609         default:
 610                 return -EINVAL;
 611         }
 612
 613         /* Linear search for block */
 614         nr = 0;
 615         list_for_each(l, h) {
 616                 blk = list_entry(l, rh_block_t, list);
 617                 if (stats != NULL && nr < max_stats) {
 618                         stats->start = blk->start;
 619                         stats->size = blk->size;
 620                         stats->owner = blk->owner;
 621                         stats++;
 622                 }
 623                 nr++;
 624         }
 625
 626         return nr;
 627 }
 628
 629 int rh_set_owner(rh_info_t * info, void *start, const char *owner)
 630 {
 631         rh_block_t *blk, *blk2;
 632         struct list_head *l;
 633         int size;
 634
 635         /* Linear search for block */
 636         blk = NULL;
 637         list_for_each(l, &info->taken_list) {
 638                 blk2 = list_entry(l, rh_block_t, list);
 639                 if (start < blk2->start)
 640                         break;
 641                 blk = blk2;
 642         }
 643
 644         if (blk == NULL || start > (blk->start + blk->size))
 645                 return -EINVAL;
 646
 647         blk->owner = owner;
 648         size = blk->size;
 649
 650         return size;
 651 }
 652
 653 void rh_dump(rh_info_t * info)
 654 {
 655         static rh_stats_t st[32];       /* XXX maximum 32 blocks */
 656         int maxnr;
 657         int i, nr;
 658
 659         maxnr = sizeof(st) / sizeof(st[0]);
 660
 661         printk(KERN_INFO
 662                "info @0x%p (%d slots empty / %d max)\n",
 663                info, info->empty_slots, info->max_blocks);
 664
 665         printk(KERN_INFO "  Free:\n");
 666         nr = rh_get_stats(info, RHGS_FREE, maxnr, st);
 667         if (nr > maxnr)
 668                 nr = maxnr;
 669         for (i = 0; i < nr; i++)
 670                 printk(KERN_INFO
 671                        "    0x%p-0x%p (%u)\n",
 672                        st[i].start, (int8_t *) st[i].start + st[i].size,
 673                        st[i].size);
 674         printk(KERN_INFO "\n");
 675
 676         printk(KERN_INFO "  Taken:\n");
 677         nr = rh_get_stats(info, RHGS_TAKEN, maxnr, st);
 678         if (nr > maxnr)
 679                 nr = maxnr;
 680         for (i = 0; i < nr; i++)
 681                 printk(KERN_INFO
 682                        "    0x%p-0x%p (%u) %s\n",
 683                        st[i].start, (int8_t *) st[i].start + st[i].size,
 684                        st[i].size, st[i].owner != NULL ? st[i].owner : "");
 685         printk(KERN_INFO "\n");
 686 }
 687
 688 void rh_dump_blk(rh_info_t * info, rh_block_t * blk)
 689 {
 690         printk(KERN_INFO
 691                "blk @0x%p: 0x%p-0x%p (%u)\n",
 692                blk, blk->start, (int8_t *) blk->start + blk->size, blk->size);
 693 }