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