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/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/slab.h>
  20
  21 #include <asm/rheap.h>
  22
  23 /*
  24  * Fixup a list_head, needed when copying lists.  If the pointers fall
  25  * between s and e, apply the delta.  This assumes that
  26  * sizeof(struct list_head *) == sizeof(unsigned long *).
  27  */
  28 static inline void fixup(unsigned long s, unsigned long e, int d,
  29                          struct list_head *l)
  30 {
  31         unsigned long *pp;
  32
  33         pp = (unsigned long *)&l->next;
  34         if (*pp >= s && *pp < e)
  35                 *pp += d;
  36
  37         pp = (unsigned long *)&l->prev;
  38         if (*pp >= s && *pp < e)
  39                 *pp += d;
  40 }
  41
  42 /* Grow the allocated blocks */
  43 static int grow(rh_info_t * info, int max_blocks)
  44 {
  45         rh_block_t *block, *blk;
  46         int i, new_blocks;
  47         int delta;
  48         unsigned long blks, blke;
  49
  50         if (max_blocks <= info->max_blocks)
  51                 return -EINVAL;
  52
  53         new_blocks = max_blocks - info->max_blocks;
  54
  55         block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_KERNEL);
  56         if (block == NULL)
  57                 return -ENOMEM;
  58
  59         if (info->max_blocks > 0) {
  60
  61                 /* copy old block area */
  62                 memcpy(block, info->block,
  63                        sizeof(rh_block_t) * info->max_blocks);
  64
  65                 delta = (char *)block - (char *)info->block;
  66
  67                 /* and fixup list pointers */
  68                 blks = (unsigned long)info->block;
  69                 blke = (unsigned long)(info->block + info->max_blocks);
  70
  71                 for (i = 0, blk = block; i < info->max_blocks; i++, blk++)
  72                         fixup(blks, blke, delta, &blk->list);
  73
  74                 fixup(blks, blke, delta, &info->empty_list);
  75                 fixup(blks, blke, delta, &info->free_list);
  76                 fixup(blks, blke, delta, &info->taken_list);
  77
  78                 /* free the old allocated memory */
  79                 if ((info->flags & RHIF_STATIC_BLOCK) == 0)
  80                         kfree(info->block);
  81         }
  82
  83         info->block = block;
  84         info->empty_slots += new_blocks;
  85         info->max_blocks = max_blocks;
  86         info->flags &= ~RHIF_STATIC_BLOCK;
  87
  88         /* add all new blocks to the free list */
  89         blk = block + info->max_blocks - new_blocks;
  90         for (i = 0; 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 = 0;
 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 = 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 = 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 && s != (before->start + before->size))
 192                 before = NULL;
 193
 194         if (after && e != 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 -= 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, unsigned long 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 = 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         if (IS_ERR_VALUE(e) || (e < s))
 342                 return -ERANGE;
 343
 344         /* Take final values */
 345         start = s;
 346         size = e - s;
 347
 348         /* Grow the blocks, if needed */
 349         r = assure_empty(info, 1);
 350         if (r < 0)
 351                 return r;
 352
 353         blk = get_slot(info);
 354         blk->start = start;
 355         blk->size = size;
 356         blk->owner = NULL;
 357
 358         attach_free_block(info, blk);
 359
 360         return 0;
 361 }
 362
 363 /* Detatch given address range, splits free block if needed. */
 364 unsigned long rh_detach_region(rh_info_t * info, unsigned long start, int size)
 365 {
 366         struct list_head *l;
 367         rh_block_t *blk, *newblk;
 368         unsigned long s, e, m, bs, be;
 369
 370         /* Validate size */
 371         if (size <= 0)
 372                 return (unsigned long) -EINVAL;
 373
 374         /* The region must be aligned */
 375         s = start;
 376         e = s + size;
 377         m = info->alignment - 1;
 378
 379         /* Round start up */
 380         s = (s + m) & ~m;
 381
 382         /* Round end down */
 383         e = e & ~m;
 384
 385         if (assure_empty(info, 1) < 0)
 386                 return (unsigned long) -ENOMEM;
 387
 388         blk = NULL;
 389         list_for_each(l, &info->free_list) {
 390                 blk = list_entry(l, rh_block_t, list);
 391                 /* The range must lie entirely inside one free block */
 392                 bs = blk->start;
 393                 be = blk->start + blk->size;
 394                 if (s >= bs && e <= be)
 395                         break;
 396                 blk = NULL;
 397         }
 398
 399         if (blk == NULL)
 400                 return (unsigned long) -ENOMEM;
 401
 402         /* Perfect fit */
 403         if (bs == s && be == e) {
 404                 /* Delete from free list, release slot */
 405                 list_del(&blk->list);
 406                 release_slot(info, blk);
 407                 return s;
 408         }
 409
 410         /* blk still in free list, with updated start and/or size */
 411         if (bs == s || be == e) {
 412                 if (bs == s)
 413                         blk->start += size;
 414                 blk->size -= size;
 415
 416         } else {
 417                 /* The front free fragment */
 418                 blk->size = s - bs;
 419
 420                 /* the back free fragment */
 421                 newblk = get_slot(info);
 422                 newblk->start = e;
 423                 newblk->size = be - e;
 424
 425                 list_add(&newblk->list, &blk->list);
 426         }
 427
 428         return s;
 429 }
 430
 431 /* Allocate a block of memory at the specified alignment.  The value returned
 432  * is an offset into the buffer initialized by rh_init(), or a negative number
 433  * if there is an error.
 434  */
 435 unsigned long rh_alloc_align(rh_info_t * info, int size, int alignment, const char *owner)
 436 {
 437         struct list_head *l;
 438         rh_block_t *blk;
 439         rh_block_t *newblk;
 440         unsigned long start;
 441
 442         /* Validate size, and alignment must be power of two */
 443         if (size <= 0 || (alignment & (alignment - 1)) != 0)
 444                 return (unsigned long) -EINVAL;
 445
 446         /* given alignment larger that default rheap alignment */
 447         if (alignment > info->alignment)
 448                 size += alignment - 1;
 449
 450         /* Align to configured alignment */
 451         size = (size + (info->alignment - 1)) & ~(info->alignment - 1);
 452
 453         if (assure_empty(info, 1) < 0)
 454                 return (unsigned long) -ENOMEM;
 455
 456         blk = NULL;
 457         list_for_each(l, &info->free_list) {
 458                 blk = list_entry(l, rh_block_t, list);
 459                 if (size <= blk->size)
 460                         break;
 461                 blk = NULL;
 462         }
 463
 464         if (blk == NULL)
 465                 return (unsigned long) -ENOMEM;
 466
 467         /* Just fits */
 468         if (blk->size == size) {
 469                 /* Move from free list to taken list */
 470                 list_del(&blk->list);
 471                 newblk = blk;
 472         } else {
 473                 newblk = get_slot(info);
 474                 newblk->start = blk->start;
 475                 newblk->size = size;
 476
 477                 /* blk still in free list, with updated start, size */
 478                 blk->start += size;
 479                 blk->size -= size;
 480         }
 481
 482         newblk->owner = owner;
 483         start = newblk->start;
 484         attach_taken_block(info, newblk);
 485
 486         /* for larger alignment return fixed up pointer  */
 487         /* this is no problem with the deallocator since */
 488         /* we scan for pointers that lie in the blocks   */
 489         if (alignment > info->alignment)
 490                 start = (start + alignment - 1) & ~(alignment - 1);
 491
 492         return start;
 493 }
 494
 495 /* Allocate a block of memory at the default alignment.  The value returned is
 496  * an offset into the buffer initialized by rh_init(), or a negative number if
 497  * there is an error.
 498  */
 499 unsigned long rh_alloc(rh_info_t * info, int size, const char *owner)
 500 {
 501         return rh_alloc_align(info, size, info->alignment, owner);
 502 }
 503
 504 /* Allocate a block of memory at the given offset, rounded up to the default
 505  * alignment.  The value returned is an offset into the buffer initialized by
 506  * rh_init(), or a negative number if there is an error.
 507  */
 508 unsigned long rh_alloc_fixed(rh_info_t * info, unsigned long start, int size, const char *owner)
 509 {
 510         struct list_head *l;
 511         rh_block_t *blk, *newblk1, *newblk2;
 512         unsigned long s, e, m, bs = 0, be = 0;
 513
 514         /* Validate size */
 515         if (size <= 0)
 516                 return (unsigned long) -EINVAL;
 517
 518         /* The region must be aligned */
 519         s = start;
 520         e = s + size;
 521         m = info->alignment - 1;
 522
 523         /* Round start up */
 524         s = (s + m) & ~m;
 525
 526         /* Round end down */
 527         e = e & ~m;
 528
 529         if (assure_empty(info, 2) < 0)
 530                 return (unsigned long) -ENOMEM;
 531
 532         blk = NULL;
 533         list_for_each(l, &info->free_list) {
 534                 blk = list_entry(l, rh_block_t, list);
 535                 /* The range must lie entirely inside one free block */
 536                 bs = blk->start;
 537                 be = blk->start + blk->size;
 538                 if (s >= bs && e <= be)
 539                         break;
 540         }
 541
 542         if (blk == NULL)
 543                 return (unsigned long) -ENOMEM;
 544
 545         /* Perfect fit */
 546         if (bs == s && be == e) {
 547                 /* Move from free list to taken list */
 548                 list_del(&blk->list);
 549                 blk->owner = owner;
 550
 551                 start = blk->start;
 552                 attach_taken_block(info, blk);
 553
 554                 return start;
 555
 556         }
 557
 558         /* blk still in free list, with updated start and/or size */
 559         if (bs == s || be == e) {
 560                 if (bs == s)
 561                         blk->start += size;
 562                 blk->size -= size;
 563
 564         } else {
 565                 /* The front free fragment */
 566                 blk->size = s - bs;
 567
 568                 /* The back free fragment */
 569                 newblk2 = get_slot(info);
 570                 newblk2->start = e;
 571                 newblk2->size = be - e;
 572
 573                 list_add(&newblk2->list, &blk->list);
 574         }
 575
 576         newblk1 = get_slot(info);
 577         newblk1->start = s;
 578         newblk1->size = e - s;
 579         newblk1->owner = owner;
 580
 581         start = newblk1->start;
 582         attach_taken_block(info, newblk1);
 583
 584         return start;
 585 }
 586
 587 /* Deallocate the memory previously allocated by one of the rh_alloc functions.
 588  * The return value is the size of the deallocated block, or a negative number
 589  * if there is an error.
 590  */
 591 int rh_free(rh_info_t * info, unsigned long start)
 592 {
 593         rh_block_t *blk, *blk2;
 594         struct list_head *l;
 595         int size;
 596
 597         /* Linear search for block */
 598         blk = NULL;
 599         list_for_each(l, &info->taken_list) {
 600                 blk2 = list_entry(l, rh_block_t, list);
 601                 if (start < blk2->start)
 602                         break;
 603                 blk = blk2;
 604         }
 605
 606         if (blk == NULL || start > (blk->start + blk->size))
 607                 return -EINVAL;
 608
 609         /* Remove from taken list */
 610         list_del(&blk->list);
 611
 612         /* Get size of freed block */
 613         size = blk->size;
 614         attach_free_block(info, blk);
 615
 616         return size;
 617 }
 618
 619 int rh_get_stats(rh_info_t * info, int what, int max_stats, rh_stats_t * stats)
 620 {
 621         rh_block_t *blk;
 622         struct list_head *l;
 623         struct list_head *h;
 624         int nr;
 625
 626         switch (what) {
 627
 628         case RHGS_FREE:
 629                 h = &info->free_list;
 630                 break;
 631
 632         case RHGS_TAKEN:
 633                 h = &info->taken_list;
 634                 break;
 635
 636         default:
 637                 return -EINVAL;
 638         }
 639
 640         /* Linear search for block */
 641         nr = 0;
 642         list_for_each(l, h) {
 643                 blk = list_entry(l, rh_block_t, list);
 644                 if (stats != NULL && nr < max_stats) {
 645                         stats->start = blk->start;
 646                         stats->size = blk->size;
 647                         stats->owner = blk->owner;
 648                         stats++;
 649                 }
 650                 nr++;
 651         }
 652
 653         return nr;
 654 }
 655
 656 int rh_set_owner(rh_info_t * info, unsigned long start, const char *owner)
 657 {
 658         rh_block_t *blk, *blk2;
 659         struct list_head *l;
 660         int size;
 661
 662         /* Linear search for block */
 663         blk = NULL;
 664         list_for_each(l, &info->taken_list) {
 665                 blk2 = list_entry(l, rh_block_t, list);
 666                 if (start < blk2->start)
 667                         break;
 668                 blk = blk2;
 669         }
 670
 671         if (blk == NULL || start > (blk->start + blk->size))
 672                 return -EINVAL;
 673
 674         blk->owner = owner;
 675         size = blk->size;
 676
 677         return size;
 678 }
 679
 680 void rh_dump(rh_info_t * info)
 681 {
 682         static rh_stats_t st[32];       /* XXX maximum 32 blocks */
 683         int maxnr;
 684         int i, nr;
 685
 686         maxnr = ARRAY_SIZE(st);
 687
 688         printk(KERN_INFO
 689                "info @0x%p (%d slots empty / %d max)\n",
 690                info, info->empty_slots, info->max_blocks);
 691
 692         printk(KERN_INFO "  Free:\n");
 693         nr = rh_get_stats(info, RHGS_FREE, maxnr, st);
 694         if (nr > maxnr)
 695                 nr = maxnr;
 696         for (i = 0; i < nr; i++)
 697                 printk(KERN_INFO
 698                        "    0x%lx-0x%lx (%u)\n",
 699                        st[i].start, st[i].start + st[i].size,
 700                        st[i].size);
 701         printk(KERN_INFO "\n");
 702
 703         printk(KERN_INFO "  Taken:\n");
 704         nr = rh_get_stats(info, RHGS_TAKEN, maxnr, st);
 705         if (nr > maxnr)
 706                 nr = maxnr;
 707         for (i = 0; i < nr; i++)
 708                 printk(KERN_INFO
 709                        "    0x%lx-0x%lx (%u) %s\n",
 710                        st[i].start, st[i].start + st[i].size,
 711                        st[i].size, st[i].owner != NULL ? st[i].owner : "");
 712         printk(KERN_INFO "\n");
 713 }
 714
 715 void rh_dump_blk(rh_info_t * info, rh_block_t * blk)
 716 {
 717         printk(KERN_INFO
 718                "blk @0x%p: 0x%lx-0x%lx (%u)\n",
 719                blk, blk->start, blk->start + blk->size, blk->size);
 720 }