mm/memblock.c

   1 /*
   2  * Procedures for maintaining information about logical memory blocks.
   3  *
   4  * Peter Bergner, IBM Corp.     June 2001.
   5  * Copyright (C) 2001 Peter Bergner.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/bitops.h>
  17 #include <linux/poison.h>
  18 #include <linux/memblock.h>
  19
  20 struct memblock memblock;
  21
  22 static int memblock_debug, memblock_can_resize;
  23 static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS + 1];
  24 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS + 1];
  25
  26 #define MEMBLOCK_ERROR  (~(phys_addr_t)0)
  27
  28 /* inline so we don't get a warning when pr_debug is compiled out */
  29 static inline const char *memblock_type_name(struct memblock_type *type)
  30 {
  31         if (type == &memblock.memory)
  32                 return "memory";
  33         else if (type == &memblock.reserved)
  34                 return "reserved";
  35         else
  36                 return "unknown";
  37 }
  38
  39 /*
  40  * Address comparison utilities
  41  */
  42
  43 static phys_addr_t memblock_align_down(phys_addr_t addr, phys_addr_t size)
  44 {
  45         return addr & ~(size - 1);
  46 }
  47
  48 static phys_addr_t memblock_align_up(phys_addr_t addr, phys_addr_t size)
  49 {
  50         return (addr + (size - 1)) & ~(size - 1);
  51 }
  52
  53 static unsigned long memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
  54                                        phys_addr_t base2, phys_addr_t size2)
  55 {
  56         return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
  57 }
  58
  59 static long memblock_addrs_adjacent(phys_addr_t base1, phys_addr_t size1,
  60                                phys_addr_t base2, phys_addr_t size2)
  61 {
  62         if (base2 == base1 + size1)
  63                 return 1;
  64         else if (base1 == base2 + size2)
  65                 return -1;
  66
  67         return 0;
  68 }
  69
  70 static long memblock_regions_adjacent(struct memblock_type *type,
  71                                  unsigned long r1, unsigned long r2)
  72 {
  73         phys_addr_t base1 = type->regions[r1].base;
  74         phys_addr_t size1 = type->regions[r1].size;
  75         phys_addr_t base2 = type->regions[r2].base;
  76         phys_addr_t size2 = type->regions[r2].size;
  77
  78         return memblock_addrs_adjacent(base1, size1, base2, size2);
  79 }
  80
  81 long memblock_overlaps_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
  82 {
  83         unsigned long i;
  84
  85         for (i = 0; i < type->cnt; i++) {
  86                 phys_addr_t rgnbase = type->regions[i].base;
  87                 phys_addr_t rgnsize = type->regions[i].size;
  88                 if (memblock_addrs_overlap(base, size, rgnbase, rgnsize))
  89                         break;
  90         }
  91
  92         return (i < type->cnt) ? i : -1;
  93 }
  94
  95 /*
  96  * Find, allocate, deallocate or reserve unreserved regions. All allocations
  97  * are top-down.
  98  */
  99
 100 static phys_addr_t __init memblock_find_region(phys_addr_t start, phys_addr_t end,
 101                                           phys_addr_t size, phys_addr_t align)
 102 {
 103         phys_addr_t base, res_base;
 104         long j;
 105
 106         base = memblock_align_down((end - size), align);
 107         while (start <= base) {
 108                 j = memblock_overlaps_region(&memblock.reserved, base, size);
 109                 if (j < 0)
 110                         return base;
 111                 res_base = memblock.reserved.regions[j].base;
 112                 if (res_base < size)
 113                         break;
 114                 base = memblock_align_down(res_base - size, align);
 115         }
 116
 117         return MEMBLOCK_ERROR;
 118 }
 119
 120 static phys_addr_t __init memblock_find_base(phys_addr_t size, phys_addr_t align,
 121                                         phys_addr_t start, phys_addr_t end)
 122 {
 123         long i;
 124
 125         BUG_ON(0 == size);
 126
 127         size = memblock_align_up(size, align);
 128
 129         /* Pump up max_addr */
 130         if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
 131                 end = memblock.current_limit;
 132
 133         /* We do a top-down search, this tends to limit memory
 134          * fragmentation by keeping early boot allocs near the
 135          * top of memory
 136          */
 137         for (i = memblock.memory.cnt - 1; i >= 0; i--) {
 138                 phys_addr_t memblockbase = memblock.memory.regions[i].base;
 139                 phys_addr_t memblocksize = memblock.memory.regions[i].size;
 140                 phys_addr_t bottom, top, found;
 141
 142                 if (memblocksize < size)
 143                         continue;
 144                 if ((memblockbase + memblocksize) <= start)
 145                         break;
 146                 bottom = max(memblockbase, start);
 147                 top = min(memblockbase + memblocksize, end);
 148                 if (bottom >= top)
 149                         continue;
 150                 found = memblock_find_region(bottom, top, size, align);
 151                 if (found != MEMBLOCK_ERROR)
 152                         return found;
 153         }
 154         return MEMBLOCK_ERROR;
 155 }
 156
 157 static void memblock_remove_region(struct memblock_type *type, unsigned long r)
 158 {
 159         unsigned long i;
 160
 161         for (i = r; i < type->cnt - 1; i++) {
 162                 type->regions[i].base = type->regions[i + 1].base;
 163                 type->regions[i].size = type->regions[i + 1].size;
 164         }
 165         type->cnt--;
 166 }
 167
 168 /* Assumption: base addr of region 1 < base addr of region 2 */
 169 static void memblock_coalesce_regions(struct memblock_type *type,
 170                 unsigned long r1, unsigned long r2)
 171 {
 172         type->regions[r1].size += type->regions[r2].size;
 173         memblock_remove_region(type, r2);
 174 }
 175
 176 /* Defined below but needed now */
 177 static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size);
 178
 179 static int memblock_double_array(struct memblock_type *type)
 180 {
 181         struct memblock_region *new_array, *old_array;
 182         phys_addr_t old_size, new_size, addr;
 183         int use_slab = slab_is_available();
 184
 185         /* We don't allow resizing until we know about the reserved regions
 186          * of memory that aren't suitable for allocation
 187          */
 188         if (!memblock_can_resize)
 189                 return -1;
 190
 191         pr_debug("memblock: %s array full, doubling...", memblock_type_name(type));
 192
 193         /* Calculate new doubled size */
 194         old_size = type->max * sizeof(struct memblock_region);
 195         new_size = old_size << 1;
 196
 197         /* Try to find some space for it.
 198          *
 199          * WARNING: We assume that either slab_is_available() and we use it or
 200          * we use MEMBLOCK for allocations. That means that this is unsafe to use
 201          * when bootmem is currently active (unless bootmem itself is implemented
 202          * on top of MEMBLOCK which isn't the case yet)
 203          *
 204          * This should however not be an issue for now, as we currently only
 205          * call into MEMBLOCK while it's still active, or much later when slab is
 206          * active for memory hotplug operations
 207          */
 208         if (use_slab) {
 209                 new_array = kmalloc(new_size, GFP_KERNEL);
 210                 addr = new_array == NULL ? MEMBLOCK_ERROR : __pa(new_array);
 211         } else
 212                 addr = memblock_find_base(new_size, sizeof(phys_addr_t), 0, MEMBLOCK_ALLOC_ACCESSIBLE);
 213         if (addr == MEMBLOCK_ERROR) {
 214                 pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
 215                        memblock_type_name(type), type->max, type->max * 2);
 216                 return -1;
 217         }
 218         new_array = __va(addr);
 219
 220         /* Found space, we now need to move the array over before
 221          * we add the reserved region since it may be our reserved
 222          * array itself that is full.
 223          */
 224         memcpy(new_array, type->regions, old_size);
 225         memset(new_array + type->max, 0, old_size);
 226         old_array = type->regions;
 227         type->regions = new_array;
 228         type->max <<= 1;
 229
 230         /* If we use SLAB that's it, we are done */
 231         if (use_slab)
 232                 return 0;
 233
 234         /* Add the new reserved region now. Should not fail ! */
 235         BUG_ON(memblock_add_region(&memblock.reserved, addr, new_size) < 0);
 236
 237         /* If the array wasn't our static init one, then free it. We only do
 238          * that before SLAB is available as later on, we don't know whether
 239          * to use kfree or free_bootmem_pages(). Shouldn't be a big deal
 240          * anyways
 241          */
 242         if (old_array != memblock_memory_init_regions &&
 243             old_array != memblock_reserved_init_regions)
 244                 memblock_free(__pa(old_array), old_size);
 245
 246         return 0;
 247 }
 248
 249 extern int __weak memblock_memory_can_coalesce(phys_addr_t addr1, phys_addr_t size1,
 250                                           phys_addr_t addr2, phys_addr_t size2)
 251 {
 252         return 1;
 253 }
 254
 255 static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
 256 {
 257         unsigned long coalesced = 0;
 258         long adjacent, i;
 259
 260         if ((type->cnt == 1) && (type->regions[0].size == 0)) {
 261                 type->regions[0].base = base;
 262                 type->regions[0].size = size;
 263                 return 0;
 264         }
 265
 266         /* First try and coalesce this MEMBLOCK with another. */
 267         for (i = 0; i < type->cnt; i++) {
 268                 phys_addr_t rgnbase = type->regions[i].base;
 269                 phys_addr_t rgnsize = type->regions[i].size;
 270
 271                 if ((rgnbase == base) && (rgnsize == size))
 272                         /* Already have this region, so we're done */
 273                         return 0;
 274
 275                 adjacent = memblock_addrs_adjacent(base, size, rgnbase, rgnsize);
 276                 /* Check if arch allows coalescing */
 277                 if (adjacent != 0 && type == &memblock.memory &&
 278                     !memblock_memory_can_coalesce(base, size, rgnbase, rgnsize))
 279                         break;
 280                 if (adjacent > 0) {
 281                         type->regions[i].base -= size;
 282                         type->regions[i].size += size;
 283                         coalesced++;
 284                         break;
 285                 } else if (adjacent < 0) {
 286                         type->regions[i].size += size;
 287                         coalesced++;
 288                         break;
 289                 }
 290         }
 291
 292         /* If we plugged a hole, we may want to also coalesce with the
 293          * next region
 294          */
 295         if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1) &&
 296             ((type != &memblock.memory || memblock_memory_can_coalesce(type->regions[i].base,
 297                                                              type->regions[i].size,
 298                                                              type->regions[i+1].base,
 299                                                              type->regions[i+1].size)))) {
 300                 memblock_coalesce_regions(type, i, i+1);
 301                 coalesced++;
 302         }
 303
 304         if (coalesced)
 305                 return coalesced;
 306
 307         /* If we are out of space, we fail. It's too late to resize the array
 308          * but then this shouldn't have happened in the first place.
 309          */
 310         if (WARN_ON(type->cnt >= type->max))
 311                 return -1;
 312
 313         /* Couldn't coalesce the MEMBLOCK, so add it to the sorted table. */
 314         for (i = type->cnt - 1; i >= 0; i--) {
 315                 if (base < type->regions[i].base) {
 316                         type->regions[i+1].base = type->regions[i].base;
 317                         type->regions[i+1].size = type->regions[i].size;
 318                 } else {
 319                         type->regions[i+1].base = base;
 320                         type->regions[i+1].size = size;
 321                         break;
 322                 }
 323         }
 324
 325         if (base < type->regions[0].base) {
 326                 type->regions[0].base = base;
 327                 type->regions[0].size = size;
 328         }
 329         type->cnt++;
 330
 331         /* The array is full ? Try to resize it. If that fails, we undo
 332          * our allocation and return an error
 333          */
 334         if (type->cnt == type->max && memblock_double_array(type)) {
 335                 type->cnt--;
 336                 return -1;
 337         }
 338
 339         return 0;
 340 }
 341
 342 long memblock_add(phys_addr_t base, phys_addr_t size)
 343 {
 344         return memblock_add_region(&memblock.memory, base, size);
 345
 346 }
 347
 348 static long __memblock_remove(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
 349 {
 350         phys_addr_t rgnbegin, rgnend;
 351         phys_addr_t end = base + size;
 352         int i;
 353
 354         rgnbegin = rgnend = 0; /* supress gcc warnings */
 355
 356         /* Find the region where (base, size) belongs to */
 357         for (i=0; i < type->cnt; i++) {
 358                 rgnbegin = type->regions[i].base;
 359                 rgnend = rgnbegin + type->regions[i].size;
 360
 361                 if ((rgnbegin <= base) && (end <= rgnend))
 362                         break;
 363         }
 364
 365         /* Didn't find the region */
 366         if (i == type->cnt)
 367                 return -1;
 368
 369         /* Check to see if we are removing entire region */
 370         if ((rgnbegin == base) && (rgnend == end)) {
 371                 memblock_remove_region(type, i);
 372                 return 0;
 373         }
 374
 375         /* Check to see if region is matching at the front */
 376         if (rgnbegin == base) {
 377                 type->regions[i].base = end;
 378                 type->regions[i].size -= size;
 379                 return 0;
 380         }
 381
 382         /* Check to see if the region is matching at the end */
 383         if (rgnend == end) {
 384                 type->regions[i].size -= size;
 385                 return 0;
 386         }
 387
 388         /*
 389          * We need to split the entry -  adjust the current one to the
 390          * beginging of the hole and add the region after hole.
 391          */
 392         type->regions[i].size = base - type->regions[i].base;
 393         return memblock_add_region(type, end, rgnend - end);
 394 }
 395
 396 long memblock_remove(phys_addr_t base, phys_addr_t size)
 397 {
 398         return __memblock_remove(&memblock.memory, base, size);
 399 }
 400
 401 long __init memblock_free(phys_addr_t base, phys_addr_t size)
 402 {
 403         return __memblock_remove(&memblock.reserved, base, size);
 404 }
 405
 406 long __init memblock_reserve(phys_addr_t base, phys_addr_t size)
 407 {
 408         struct memblock_type *_rgn = &memblock.reserved;
 409
 410         BUG_ON(0 == size);
 411
 412         return memblock_add_region(_rgn, base, size);
 413 }
 414
 415 phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
 416 {
 417         phys_addr_t found;
 418
 419         /* We align the size to limit fragmentation. Without this, a lot of
 420          * small allocs quickly eat up the whole reserve array on sparc
 421          */
 422         size = memblock_align_up(size, align);
 423
 424         found = memblock_find_base(size, align, 0, max_addr);
 425         if (found != MEMBLOCK_ERROR &&
 426             memblock_add_region(&memblock.reserved, found, size) >= 0)
 427                 return found;
 428
 429         return 0;
 430 }
 431
 432 phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
 433 {
 434         phys_addr_t alloc;
 435
 436         alloc = __memblock_alloc_base(size, align, max_addr);
 437
 438         if (alloc == 0)
 439                 panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
 440                       (unsigned long long) size, (unsigned long long) max_addr);
 441
 442         return alloc;
 443 }
 444
 445 phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align)
 446 {
 447         return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
 448 }
 449
 450
 451 /*
 452  * Additional node-local allocators. Search for node memory is bottom up
 453  * and walks memblock regions within that node bottom-up as well, but allocation
 454  * within an memblock region is top-down.
 455  */
 456
 457 phys_addr_t __weak __init memblock_nid_range(phys_addr_t start, phys_addr_t end, int *nid)
 458 {
 459         *nid = 0;
 460
 461         return end;
 462 }
 463
 464 static phys_addr_t __init memblock_alloc_nid_region(struct memblock_region *mp,
 465                                                phys_addr_t size,
 466                                                phys_addr_t align, int nid)
 467 {
 468         phys_addr_t start, end;
 469
 470         start = mp->base;
 471         end = start + mp->size;
 472
 473         start = memblock_align_up(start, align);
 474         while (start < end) {
 475                 phys_addr_t this_end;
 476                 int this_nid;
 477
 478                 this_end = memblock_nid_range(start, end, &this_nid);
 479                 if (this_nid == nid) {
 480                         phys_addr_t ret = memblock_find_region(start, this_end, size, align);
 481                         if (ret != MEMBLOCK_ERROR &&
 482                             memblock_add_region(&memblock.reserved, ret, size) >= 0)
 483                                 return ret;
 484                 }
 485                 start = this_end;
 486         }
 487
 488         return MEMBLOCK_ERROR;
 489 }
 490
 491 phys_addr_t __init memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int nid)
 492 {
 493         struct memblock_type *mem = &memblock.memory;
 494         int i;
 495
 496         BUG_ON(0 == size);
 497
 498         /* We align the size to limit fragmentation. Without this, a lot of
 499          * small allocs quickly eat up the whole reserve array on sparc
 500          */
 501         size = memblock_align_up(size, align);
 502
 503         /* We do a bottom-up search for a region with the right
 504          * nid since that's easier considering how memblock_nid_range()
 505          * works
 506          */
 507         for (i = 0; i < mem->cnt; i++) {
 508                 phys_addr_t ret = memblock_alloc_nid_region(&mem->regions[i],
 509                                                size, align, nid);
 510                 if (ret != MEMBLOCK_ERROR)
 511                         return ret;
 512         }
 513
 514         return memblock_alloc(size, align);
 515 }
 516
 517 /* You must call memblock_analyze() before this. */
 518 phys_addr_t __init memblock_phys_mem_size(void)
 519 {
 520         return memblock.memory_size;
 521 }
 522
 523 phys_addr_t memblock_end_of_DRAM(void)
 524 {
 525         int idx = memblock.memory.cnt - 1;
 526
 527         return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
 528 }
 529
 530 /* You must call memblock_analyze() after this. */
 531 void __init memblock_enforce_memory_limit(phys_addr_t memory_limit)
 532 {
 533         unsigned long i;
 534         phys_addr_t limit;
 535         struct memblock_region *p;
 536
 537         if (!memory_limit)
 538                 return;
 539
 540         /* Truncate the memblock regions to satisfy the memory limit. */
 541         limit = memory_limit;
 542         for (i = 0; i < memblock.memory.cnt; i++) {
 543                 if (limit > memblock.memory.regions[i].size) {
 544                         limit -= memblock.memory.regions[i].size;
 545                         continue;
 546                 }
 547
 548                 memblock.memory.regions[i].size = limit;
 549                 memblock.memory.cnt = i + 1;
 550                 break;
 551         }
 552
 553         memory_limit = memblock_end_of_DRAM();
 554
 555         /* And truncate any reserves above the limit also. */
 556         for (i = 0; i < memblock.reserved.cnt; i++) {
 557                 p = &memblock.reserved.regions[i];
 558
 559                 if (p->base > memory_limit)
 560                         p->size = 0;
 561                 else if ((p->base + p->size) > memory_limit)
 562                         p->size = memory_limit - p->base;
 563
 564                 if (p->size == 0) {
 565                         memblock_remove_region(&memblock.reserved, i);
 566                         i--;
 567                 }
 568         }
 569 }
 570
 571 static int memblock_search(struct memblock_type *type, phys_addr_t addr)
 572 {
 573         unsigned int left = 0, right = type->cnt;
 574
 575         do {
 576                 unsigned int mid = (right + left) / 2;
 577
 578                 if (addr < type->regions[mid].base)
 579                         right = mid;
 580                 else if (addr >= (type->regions[mid].base +
 581                                   type->regions[mid].size))
 582                         left = mid + 1;
 583                 else
 584                         return mid;
 585         } while (left < right);
 586         return -1;
 587 }
 588
 589 int __init memblock_is_reserved(phys_addr_t addr)
 590 {
 591         return memblock_search(&memblock.reserved, addr) != -1;
 592 }
 593
 594 int memblock_is_memory(phys_addr_t addr)
 595 {
 596         return memblock_search(&memblock.memory, addr) != -1;
 597 }
 598
 599 int memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
 600 {
 601         int idx = memblock_search(&memblock.reserved, base);
 602
 603         if (idx == -1)
 604                 return 0;
 605         return memblock.reserved.regions[idx].base <= base &&
 606                 (memblock.reserved.regions[idx].base +
 607                  memblock.reserved.regions[idx].size) >= (base + size);
 608 }
 609
 610 int memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
 611 {
 612         return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
 613 }
 614
 615
 616 void __init memblock_set_current_limit(phys_addr_t limit)
 617 {
 618         memblock.current_limit = limit;
 619 }
 620
 621 static void memblock_dump(struct memblock_type *region, char *name)
 622 {
 623         unsigned long long base, size;
 624         int i;
 625
 626         pr_info(" %s.cnt  = 0x%lx\n", name, region->cnt);
 627
 628         for (i = 0; i < region->cnt; i++) {
 629                 base = region->regions[i].base;
 630                 size = region->regions[i].size;
 631
 632                 pr_info(" %s[0x%x]\t0x%016llx - 0x%016llx, 0x%llx bytes\n",
 633                     name, i, base, base + size - 1, size);
 634         }
 635 }
 636
 637 void memblock_dump_all(void)
 638 {
 639         if (!memblock_debug)
 640                 return;
 641
 642         pr_info("MEMBLOCK configuration:\n");
 643         pr_info(" memory size = 0x%llx\n", (unsigned long long)memblock.memory_size);
 644
 645         memblock_dump(&memblock.memory, "memory");
 646         memblock_dump(&memblock.reserved, "reserved");
 647 }
 648
 649 void __init memblock_analyze(void)
 650 {
 651         int i;
 652
 653         /* Check marker in the unused last array entry */
 654         WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
 655                 != (phys_addr_t)RED_INACTIVE);
 656         WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
 657                 != (phys_addr_t)RED_INACTIVE);
 658
 659         memblock.memory_size = 0;
 660
 661         for (i = 0; i < memblock.memory.cnt; i++)
 662                 memblock.memory_size += memblock.memory.regions[i].size;
 663
 664         /* We allow resizing from there */
 665         memblock_can_resize = 1;
 666 }
 667
 668 void __init memblock_init(void)
 669 {
 670         /* Hookup the initial arrays */
 671         memblock.memory.regions = memblock_memory_init_regions;
 672         memblock.memory.max             = INIT_MEMBLOCK_REGIONS;
 673         memblock.reserved.regions       = memblock_reserved_init_regions;
 674         memblock.reserved.max   = INIT_MEMBLOCK_REGIONS;
 675
 676         /* Write a marker in the unused last array entry */
 677         memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
 678         memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
 679
 680         /* Create a dummy zero size MEMBLOCK which will get coalesced away later.
 681          * This simplifies the memblock_add() code below...
 682          */
 683         memblock.memory.regions[0].base = 0;
 684         memblock.memory.regions[0].size = 0;
 685         memblock.memory.cnt = 1;
 686
 687         /* Ditto. */
 688         memblock.reserved.regions[0].base = 0;
 689         memblock.reserved.regions[0].size = 0;
 690         memblock.reserved.cnt = 1;
 691
 692         memblock.current_limit = MEMBLOCK_ALLOC_ANYWHERE;
 693 }
 694
 695 static int __init early_memblock(char *p)
 696 {
 697         if (p && strstr(p, "debug"))
 698                 memblock_debug = 1;
 699         return 0;
 700 }
 701 early_param("memblock", early_memblock);
 702