mm/bootmem.c

   1 /*
   2  *  bootmem - A boot-time physical memory allocator and configurator
   3  *
   4  *  Copyright (C) 1999 Ingo Molnar
   5  *                1999 Kanoj Sarcar, SGI
   6  *                2008 Johannes Weiner
   7  *
   8  * Access to this subsystem has to be serialized externally (which is true
   9  * for the boot process anyway).
  10  */
  11 #include <linux/init.h>
  12 #include <linux/pfn.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/module.h>
  15
  16 #include <asm/bug.h>
  17 #include <asm/io.h>
  18 #include <asm/processor.h>
  19
  20 #include "internal.h"
  21
  22 unsigned long max_low_pfn;
  23 unsigned long min_low_pfn;
  24 unsigned long max_pfn;
  25
  26 #ifdef CONFIG_CRASH_DUMP
  27 /*
  28  * If we have booted due to a crash, max_pfn will be a very low value. We need
  29  * to know the amount of memory that the previous kernel used.
  30  */
  31 unsigned long saved_max_pfn;
  32 #endif
  33
  34 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
  35
  36 static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
  37
  38 static int bootmem_debug;
  39
  40 static int __init bootmem_debug_setup(char *buf)
  41 {
  42         bootmem_debug = 1;
  43         return 0;
  44 }
  45 early_param("bootmem_debug", bootmem_debug_setup);
  46
  47 #define bdebug(fmt, args...) ({                         \
  48         if (unlikely(bootmem_debug))                    \
  49                 printk(KERN_INFO                        \
  50                         "bootmem::%s " fmt,             \
  51                         __FUNCTION__, ## args);         \
  52 })
  53
  54 static unsigned long __init bootmap_bytes(unsigned long pages)
  55 {
  56         unsigned long bytes = (pages + 7) / 8;
  57
  58         return ALIGN(bytes, sizeof(long));
  59 }
  60
  61 /**
  62  * bootmem_bootmap_pages - calculate bitmap size in pages
  63  * @pages: number of pages the bitmap has to represent
  64  */
  65 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
  66 {
  67         unsigned long bytes = bootmap_bytes(pages);
  68
  69         return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
  70 }
  71
  72 /*
  73  * link bdata in order
  74  */
  75 static void __init link_bootmem(bootmem_data_t *bdata)
  76 {
  77         struct list_head *iter;
  78
  79         list_for_each(iter, &bdata_list) {
  80                 bootmem_data_t *ent;
  81
  82                 ent = list_entry(iter, bootmem_data_t, list);
  83                 if (bdata->node_boot_start < ent->node_boot_start)
  84                         break;
  85         }
  86         list_add_tail(&bdata->list, iter);
  87 }
  88
  89 /*
  90  * Called once to set up the allocator itself.
  91  */
  92 static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
  93         unsigned long mapstart, unsigned long start, unsigned long end)
  94 {
  95         unsigned long mapsize;
  96
  97         mminit_validate_memmodel_limits(&start, &end);
  98         bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
  99         bdata->node_boot_start = PFN_PHYS(start);
 100         bdata->node_low_pfn = end;
 101         link_bootmem(bdata);
 102
 103         /*
 104          * Initially all pages are reserved - setup_arch() has to
 105          * register free RAM areas explicitly.
 106          */
 107         mapsize = bootmap_bytes(end - start);
 108         memset(bdata->node_bootmem_map, 0xff, mapsize);
 109
 110         bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
 111                 bdata - bootmem_node_data, start, mapstart, end, mapsize);
 112
 113         return mapsize;
 114 }
 115
 116 /**
 117  * init_bootmem_node - register a node as boot memory
 118  * @pgdat: node to register
 119  * @freepfn: pfn where the bitmap for this node is to be placed
 120  * @startpfn: first pfn on the node
 121  * @endpfn: first pfn after the node
 122  *
 123  * Returns the number of bytes needed to hold the bitmap for this node.
 124  */
 125 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
 126                                 unsigned long startpfn, unsigned long endpfn)
 127 {
 128         return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
 129 }
 130
 131 /**
 132  * init_bootmem - register boot memory
 133  * @start: pfn where the bitmap is to be placed
 134  * @pages: number of available physical pages
 135  *
 136  * Returns the number of bytes needed to hold the bitmap.
 137  */
 138 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
 139 {
 140         max_low_pfn = pages;
 141         min_low_pfn = start;
 142         return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
 143 }
 144
 145 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 146 {
 147         int aligned;
 148         struct page *page;
 149         unsigned long start, end, pages, count = 0;
 150
 151         if (!bdata->node_bootmem_map)
 152                 return 0;
 153
 154         start = PFN_DOWN(bdata->node_boot_start);
 155         end = bdata->node_low_pfn;
 156
 157         /*
 158          * If the start is aligned to the machines wordsize, we might
 159          * be able to free pages in bulks of that order.
 160          */
 161         aligned = !(start & (BITS_PER_LONG - 1));
 162
 163         bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
 164                 bdata - bootmem_node_data, start, end, aligned);
 165
 166         while (start < end) {
 167                 unsigned long *map, idx, vec;
 168
 169                 map = bdata->node_bootmem_map;
 170                 idx = start - PFN_DOWN(bdata->node_boot_start);
 171                 vec = ~map[idx / BITS_PER_LONG];
 172
 173                 if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
 174                         int order = ilog2(BITS_PER_LONG);
 175
 176                         __free_pages_bootmem(pfn_to_page(start), order);
 177                         count += BITS_PER_LONG;
 178                 } else {
 179                         unsigned long off = 0;
 180
 181                         while (vec && off < BITS_PER_LONG) {
 182                                 if (vec & 1) {
 183                                         page = pfn_to_page(start + off);
 184                                         __free_pages_bootmem(page, 0);
 185                                         count++;
 186                                 }
 187                                 vec >>= 1;
 188                                 off++;
 189                         }
 190                 }
 191                 start += BITS_PER_LONG;
 192         }
 193
 194         page = virt_to_page(bdata->node_bootmem_map);
 195         pages = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 196         pages = bootmem_bootmap_pages(pages);
 197         count += pages;
 198         while (pages--)
 199                 __free_pages_bootmem(page++, 0);
 200
 201         bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
 202
 203         return count;
 204 }
 205
 206 /**
 207  * free_all_bootmem_node - release a node's free pages to the buddy allocator
 208  * @pgdat: node to be released
 209  *
 210  * Returns the number of pages actually released.
 211  */
 212 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
 213 {
 214         register_page_bootmem_info_node(pgdat);
 215         return free_all_bootmem_core(pgdat->bdata);
 216 }
 217
 218 /**
 219  * free_all_bootmem - release free pages to the buddy allocator
 220  *
 221  * Returns the number of pages actually released.
 222  */
 223 unsigned long __init free_all_bootmem(void)
 224 {
 225         return free_all_bootmem_core(NODE_DATA(0)->bdata);
 226 }
 227
 228 static void __init __free(bootmem_data_t *bdata,
 229                         unsigned long sidx, unsigned long eidx)
 230 {
 231         unsigned long idx;
 232
 233         bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
 234                 sidx + PFN_DOWN(bdata->node_boot_start),
 235                 eidx + PFN_DOWN(bdata->node_boot_start));
 236
 237         for (idx = sidx; idx < eidx; idx++)
 238                 if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
 239                         BUG();
 240 }
 241
 242 static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
 243                         unsigned long eidx, int flags)
 244 {
 245         unsigned long idx;
 246         int exclusive = flags & BOOTMEM_EXCLUSIVE;
 247
 248         bdebug("nid=%td start=%lx end=%lx flags=%x\n",
 249                 bdata - bootmem_node_data,
 250                 sidx + PFN_DOWN(bdata->node_boot_start),
 251                 eidx + PFN_DOWN(bdata->node_boot_start),
 252                 flags);
 253
 254         for (idx = sidx; idx < eidx; idx++)
 255                 if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
 256                         if (exclusive) {
 257                                 __free(bdata, sidx, idx);
 258                                 return -EBUSY;
 259                         }
 260                         bdebug("silent double reserve of PFN %lx\n",
 261                                 idx + PFN_DOWN(bdata->node_boot_start));
 262                 }
 263         return 0;
 264 }
 265
 266 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
 267                                      unsigned long size)
 268 {
 269         unsigned long sidx, eidx;
 270         unsigned long i;
 271
 272         BUG_ON(!size);
 273
 274         /* out range */
 275         if (addr + size < bdata->node_boot_start ||
 276                 PFN_DOWN(addr) > bdata->node_low_pfn)
 277                 return;
 278         /*
 279          * round down end of usable mem, partially free pages are
 280          * considered reserved.
 281          */
 282
 283         if (addr >= bdata->node_boot_start &&
 284                         PFN_DOWN(addr - bdata->node_boot_start) < bdata->hint_idx)
 285                 bdata->hint_idx = PFN_DOWN(addr - bdata->node_boot_start);
 286
 287         /*
 288          * Round up to index to the range.
 289          */
 290         if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
 291                 sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
 292         else
 293                 sidx = 0;
 294
 295         eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
 296         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 297                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 298
 299         __free(bdata, sidx, eidx);
 300 }
 301
 302 /**
 303  * free_bootmem_node - mark a page range as usable
 304  * @pgdat: node the range resides on
 305  * @physaddr: starting address of the range
 306  * @size: size of the range in bytes
 307  *
 308  * Partial pages will be considered reserved and left as they are.
 309  *
 310  * Only physical pages that actually reside on @pgdat are marked.
 311  */
 312 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 313                               unsigned long size)
 314 {
 315         free_bootmem_core(pgdat->bdata, physaddr, size);
 316 }
 317
 318 /**
 319  * free_bootmem - mark a page range as usable
 320  * @addr: starting address of the range
 321  * @size: size of the range in bytes
 322  *
 323  * Partial pages will be considered reserved and left as they are.
 324  *
 325  * All physical pages within the range are marked, no matter what
 326  * node they reside on.
 327  */
 328 void __init free_bootmem(unsigned long addr, unsigned long size)
 329 {
 330         bootmem_data_t *bdata;
 331         list_for_each_entry(bdata, &bdata_list, list)
 332                 free_bootmem_core(bdata, addr, size);
 333 }
 334
 335 /*
 336  * Marks a particular physical memory range as unallocatable. Usable RAM
 337  * might be used for boot-time allocations - or it might get added
 338  * to the free page pool later on.
 339  */
 340 static int __init can_reserve_bootmem_core(bootmem_data_t *bdata,
 341                         unsigned long addr, unsigned long size, int flags)
 342 {
 343         unsigned long sidx, eidx;
 344         unsigned long i;
 345
 346         BUG_ON(!size);
 347
 348         /* out of range, don't hold other */
 349         if (addr + size < bdata->node_boot_start ||
 350                 PFN_DOWN(addr) > bdata->node_low_pfn)
 351                 return 0;
 352
 353         /*
 354          * Round up to index to the range.
 355          */
 356         if (addr > bdata->node_boot_start)
 357                 sidx= PFN_DOWN(addr - bdata->node_boot_start);
 358         else
 359                 sidx = 0;
 360
 361         eidx = PFN_UP(addr + size - bdata->node_boot_start);
 362         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 363                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 364
 365         for (i = sidx; i < eidx; i++) {
 366                 if (test_bit(i, bdata->node_bootmem_map)) {
 367                         if (flags & BOOTMEM_EXCLUSIVE)
 368                                 return -EBUSY;
 369                 }
 370         }
 371
 372         return 0;
 373
 374 }
 375
 376 static void __init reserve_bootmem_core(bootmem_data_t *bdata,
 377                         unsigned long addr, unsigned long size, int flags)
 378 {
 379         unsigned long sidx, eidx;
 380         unsigned long i;
 381
 382         BUG_ON(!size);
 383
 384         /* out of range */
 385         if (addr + size < bdata->node_boot_start ||
 386                 PFN_DOWN(addr) > bdata->node_low_pfn)
 387                 return;
 388
 389         /*
 390          * Round up to index to the range.
 391          */
 392         if (addr > bdata->node_boot_start)
 393                 sidx= PFN_DOWN(addr - bdata->node_boot_start);
 394         else
 395                 sidx = 0;
 396
 397         eidx = PFN_UP(addr + size - bdata->node_boot_start);
 398         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 399                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 400
 401         return __reserve(bdata, sidx, eidx, flags);
 402 }
 403
 404 /**
 405  * reserve_bootmem_node - mark a page range as reserved
 406  * @pgdat: node the range resides on
 407  * @physaddr: starting address of the range
 408  * @size: size of the range in bytes
 409  * @flags: reservation flags (see linux/bootmem.h)
 410  *
 411  * Partial pages will be reserved.
 412  *
 413  * Only physical pages that actually reside on @pgdat are marked.
 414  */
 415 int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 416                                  unsigned long size, int flags)
 417 {
 418         int ret;
 419
 420         ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 421         if (ret < 0)
 422                 return -ENOMEM;
 423         reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 424         return 0;
 425 }
 426
 427 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 428 /**
 429  * reserve_bootmem - mark a page range as usable
 430  * @addr: starting address of the range
 431  * @size: size of the range in bytes
 432  * @flags: reservation flags (see linux/bootmem.h)
 433  *
 434  * Partial pages will be reserved.
 435  *
 436  * All physical pages within the range are marked, no matter what
 437  * node they reside on.
 438  */
 439 int __init reserve_bootmem(unsigned long addr, unsigned long size,
 440                             int flags)
 441 {
 442         bootmem_data_t *bdata;
 443         int ret;
 444
 445         list_for_each_entry(bdata, &bdata_list, list) {
 446                 ret = can_reserve_bootmem_core(bdata, addr, size, flags);
 447                 if (ret < 0)
 448                         return ret;
 449         }
 450         list_for_each_entry(bdata, &bdata_list, list)
 451                 reserve_bootmem_core(bdata, addr, size, flags);
 452
 453         return 0;
 454 }
 455 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
 456
 457 static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
 458                                 unsigned long size, unsigned long align,
 459                                 unsigned long goal, unsigned long limit)
 460 {
 461         unsigned long min, max, start, sidx, midx, step;
 462
 463         BUG_ON(!size);
 464         BUG_ON(align & (align - 1));
 465         BUG_ON(limit && goal + size > limit);
 466
 467         if (!bdata->node_bootmem_map)
 468                 return NULL;
 469
 470         bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
 471                 bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
 472                 align, goal, limit);
 473
 474         min = PFN_DOWN(bdata->node_boot_start);
 475         max = bdata->node_low_pfn;
 476
 477         goal >>= PAGE_SHIFT;
 478         limit >>= PAGE_SHIFT;
 479
 480         if (limit && max > limit)
 481                 max = limit;
 482         if (max <= min)
 483                 return NULL;
 484
 485         step = max(align >> PAGE_SHIFT, 1UL);
 486
 487         if (goal && min < goal && goal < max)
 488                 start = ALIGN(goal, step);
 489         else
 490                 start = ALIGN(min, step);
 491
 492         sidx = start - PFN_DOWN(bdata->node_boot_start);
 493         midx = max - PFN_DOWN(bdata->node_boot_start);
 494
 495         if (bdata->hint_idx > sidx) {
 496                 /* Make sure we retry on failure */
 497                 goal = 1;
 498                 sidx = ALIGN(bdata->hint_idx, step);
 499         }
 500
 501         while (1) {
 502                 int merge;
 503                 void *region;
 504                 unsigned long eidx, i, start_off, end_off;
 505 find_block:
 506                 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
 507                 sidx = ALIGN(sidx, step);
 508                 eidx = sidx + PFN_UP(size);
 509
 510                 if (sidx >= midx || eidx > midx)
 511                         break;
 512
 513                 for (i = sidx; i < eidx; i++)
 514                         if (test_bit(i, bdata->node_bootmem_map)) {
 515                                 sidx = ALIGN(i, step);
 516                                 if (sidx == i)
 517                                         sidx += step;
 518                                 goto find_block;
 519                         }
 520
 521                 if (bdata->last_end_off &&
 522                                 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
 523                         start_off = ALIGN(bdata->last_end_off, align);
 524                 else
 525                         start_off = PFN_PHYS(sidx);
 526
 527                 merge = PFN_DOWN(start_off) < sidx;
 528                 end_off = start_off + size;
 529
 530                 bdata->last_end_off = end_off;
 531                 bdata->hint_idx = PFN_UP(end_off);
 532
 533                 /*
 534                  * Reserve the area now:
 535                  */
 536                 if (__reserve(bdata, PFN_DOWN(start_off) + merge,
 537                                 PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
 538                         BUG();
 539
 540                 region = phys_to_virt(bdata->node_boot_start + start_off);
 541                 memset(region, 0, size);
 542                 return region;
 543         }
 544
 545         if (goal) {
 546                 goal = 0;
 547                 sidx = 0;
 548                 goto find_block;
 549         }
 550
 551         return NULL;
 552 }
 553
 554 /**
 555  * __alloc_bootmem_nopanic - allocate boot memory without panicking
 556  * @size: size of the request in bytes
 557  * @align: alignment of the region
 558  * @goal: preferred starting address of the region
 559  *
 560  * The goal is dropped if it can not be satisfied and the allocation will
 561  * fall back to memory below @goal.
 562  *
 563  * Allocation may happen on any node in the system.
 564  *
 565  * Returns NULL on failure.
 566  */
 567 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
 568                                       unsigned long goal)
 569 {
 570         bootmem_data_t *bdata;
 571         void *ptr;
 572
 573         list_for_each_entry(bdata, &bdata_list, list) {
 574                 ptr = alloc_bootmem_core(bdata, size, align, goal, 0);
 575                 if (ptr)
 576                         return ptr;
 577         }
 578         return NULL;
 579 }
 580
 581 /**
 582  * __alloc_bootmem - allocate boot memory
 583  * @size: size of the request in bytes
 584  * @align: alignment of the region
 585  * @goal: preferred starting address of the region
 586  *
 587  * The goal is dropped if it can not be satisfied and the allocation will
 588  * fall back to memory below @goal.
 589  *
 590  * Allocation may happen on any node in the system.
 591  *
 592  * The function panics if the request can not be satisfied.
 593  */
 594 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
 595                               unsigned long goal)
 596 {
 597         void *mem = __alloc_bootmem_nopanic(size,align,goal);
 598
 599         if (mem)
 600                 return mem;
 601         /*
 602          * Whoops, we cannot satisfy the allocation request.
 603          */
 604         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 605         panic("Out of memory");
 606         return NULL;
 607 }
 608
 609 /**
 610  * __alloc_bootmem_node - allocate boot memory from a specific node
 611  * @pgdat: node to allocate from
 612  * @size: size of the request in bytes
 613  * @align: alignment of the region
 614  * @goal: preferred starting address of the region
 615  *
 616  * The goal is dropped if it can not be satisfied and the allocation will
 617  * fall back to memory below @goal.
 618  *
 619  * Allocation may fall back to any node in the system if the specified node
 620  * can not hold the requested memory.
 621  *
 622  * The function panics if the request can not be satisfied.
 623  */
 624 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
 625                                    unsigned long align, unsigned long goal)
 626 {
 627         void *ptr;
 628
 629         ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 630         if (ptr)
 631                 return ptr;
 632
 633         return __alloc_bootmem(size, align, goal);
 634 }
 635
 636 #ifdef CONFIG_SPARSEMEM
 637 /**
 638  * alloc_bootmem_section - allocate boot memory from a specific section
 639  * @size: size of the request in bytes
 640  * @section_nr: sparse map section to allocate from
 641  *
 642  * Return NULL on failure.
 643  */
 644 void * __init alloc_bootmem_section(unsigned long size,
 645                                     unsigned long section_nr)
 646 {
 647         void *ptr;
 648         unsigned long limit, goal, start_nr, end_nr, pfn;
 649         struct pglist_data *pgdat;
 650
 651         pfn = section_nr_to_pfn(section_nr);
 652         goal = PFN_PHYS(pfn);
 653         limit = PFN_PHYS(section_nr_to_pfn(section_nr + 1)) - 1;
 654         pgdat = NODE_DATA(early_pfn_to_nid(pfn));
 655         ptr = alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
 656                                 limit);
 657
 658         if (!ptr)
 659                 return NULL;
 660
 661         start_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr)));
 662         end_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr) + size));
 663         if (start_nr != section_nr || end_nr != section_nr) {
 664                 printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
 665                        section_nr);
 666                 free_bootmem_core(pgdat->bdata, __pa(ptr), size);
 667                 ptr = NULL;
 668         }
 669
 670         return ptr;
 671 }
 672 #endif
 673
 674 void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
 675                                    unsigned long align, unsigned long goal)
 676 {
 677         void *ptr;
 678
 679         ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 680         if (ptr)
 681                 return ptr;
 682
 683         return __alloc_bootmem_nopanic(size, align, goal);
 684 }
 685
 686 #ifndef ARCH_LOW_ADDRESS_LIMIT
 687 #define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL
 688 #endif
 689
 690 /**
 691  * __alloc_bootmem_low - allocate low boot memory
 692  * @size: size of the request in bytes
 693  * @align: alignment of the region
 694  * @goal: preferred starting address of the region
 695  *
 696  * The goal is dropped if it can not be satisfied and the allocation will
 697  * fall back to memory below @goal.
 698  *
 699  * Allocation may happen on any node in the system.
 700  *
 701  * The function panics if the request can not be satisfied.
 702  */
 703 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
 704                                   unsigned long goal)
 705 {
 706         bootmem_data_t *bdata;
 707         void *ptr;
 708
 709         list_for_each_entry(bdata, &bdata_list, list) {
 710                 ptr = alloc_bootmem_core(bdata, size, align, goal,
 711                                         ARCH_LOW_ADDRESS_LIMIT);
 712                 if (ptr)
 713                         return ptr;
 714         }
 715
 716         /*
 717          * Whoops, we cannot satisfy the allocation request.
 718          */
 719         printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
 720         panic("Out of low memory");
 721         return NULL;
 722 }
 723
 724 /**
 725  * __alloc_bootmem_low_node - allocate low boot memory from a specific node
 726  * @pgdat: node to allocate from
 727  * @size: size of the request in bytes
 728  * @align: alignment of the region
 729  * @goal: preferred starting address of the region
 730  *
 731  * The goal is dropped if it can not be satisfied and the allocation will
 732  * fall back to memory below @goal.
 733  *
 734  * Allocation may fall back to any node in the system if the specified node
 735  * can not hold the requested memory.
 736  *
 737  * The function panics if the request can not be satisfied.
 738  */
 739 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
 740                                        unsigned long align, unsigned long goal)
 741 {
 742         return alloc_bootmem_core(pgdat->bdata, size, align, goal,
 743                                 ARCH_LOW_ADDRESS_LIMIT);
 744 }