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 #include <linux/kmemleak.h>
  16
  17 #include <asm/bug.h>
  18 #include <asm/io.h>
  19 #include <asm/processor.h>
  20
  21 #include "internal.h"
  22
  23 unsigned long max_low_pfn;
  24 unsigned long min_low_pfn;
  25 unsigned long max_pfn;
  26
  27 #ifdef CONFIG_CRASH_DUMP
  28 /*
  29  * If we have booted due to a crash, max_pfn will be a very low value. We need
  30  * to know the amount of memory that the previous kernel used.
  31  */
  32 unsigned long saved_max_pfn;
  33 #endif
  34
  35 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
  36
  37 static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
  38
  39 static int bootmem_debug;
  40
  41 static int __init bootmem_debug_setup(char *buf)
  42 {
  43         bootmem_debug = 1;
  44         return 0;
  45 }
  46 early_param("bootmem_debug", bootmem_debug_setup);
  47
  48 #define bdebug(fmt, args...) ({                         \
  49         if (unlikely(bootmem_debug))                    \
  50                 printk(KERN_INFO                        \
  51                         "bootmem::%s " fmt,             \
  52                         __func__, ## args);             \
  53 })
  54
  55 static unsigned long __init bootmap_bytes(unsigned long pages)
  56 {
  57         unsigned long bytes = (pages + 7) / 8;
  58
  59         return ALIGN(bytes, sizeof(long));
  60 }
  61
  62 /**
  63  * bootmem_bootmap_pages - calculate bitmap size in pages
  64  * @pages: number of pages the bitmap has to represent
  65  */
  66 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
  67 {
  68         unsigned long bytes = bootmap_bytes(pages);
  69
  70         return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
  71 }
  72
  73 /*
  74  * link bdata in order
  75  */
  76 static void __init link_bootmem(bootmem_data_t *bdata)
  77 {
  78         struct list_head *iter;
  79
  80         list_for_each(iter, &bdata_list) {
  81                 bootmem_data_t *ent;
  82
  83                 ent = list_entry(iter, bootmem_data_t, list);
  84                 if (bdata->node_min_pfn < ent->node_min_pfn)
  85                         break;
  86         }
  87         list_add_tail(&bdata->list, iter);
  88 }
  89
  90 /*
  91  * Called once to set up the allocator itself.
  92  */
  93 static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
  94         unsigned long mapstart, unsigned long start, unsigned long end)
  95 {
  96         unsigned long mapsize;
  97
  98         mminit_validate_memmodel_limits(&start, &end);
  99         bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
 100         bdata->node_min_pfn = start;
 101         bdata->node_low_pfn = end;
 102         link_bootmem(bdata);
 103
 104         /*
 105          * Initially all pages are reserved - setup_arch() has to
 106          * register free RAM areas explicitly.
 107          */
 108         mapsize = bootmap_bytes(end - start);
 109         memset(bdata->node_bootmem_map, 0xff, mapsize);
 110
 111         bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
 112                 bdata - bootmem_node_data, start, mapstart, end, mapsize);
 113
 114         return mapsize;
 115 }
 116
 117 /**
 118  * init_bootmem_node - register a node as boot memory
 119  * @pgdat: node to register
 120  * @freepfn: pfn where the bitmap for this node is to be placed
 121  * @startpfn: first pfn on the node
 122  * @endpfn: first pfn after the node
 123  *
 124  * Returns the number of bytes needed to hold the bitmap for this node.
 125  */
 126 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
 127                                 unsigned long startpfn, unsigned long endpfn)
 128 {
 129         return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
 130 }
 131
 132 /**
 133  * init_bootmem - register boot memory
 134  * @start: pfn where the bitmap is to be placed
 135  * @pages: number of available physical pages
 136  *
 137  * Returns the number of bytes needed to hold the bitmap.
 138  */
 139 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
 140 {
 141         max_low_pfn = pages;
 142         min_low_pfn = start;
 143         return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
 144 }
 145
 146 /*
 147  * free_bootmem_late - free bootmem pages directly to page allocator
 148  * @addr: starting address of the range
 149  * @size: size of the range in bytes
 150  *
 151  * This is only useful when the bootmem allocator has already been torn
 152  * down, but we are still initializing the system.  Pages are given directly
 153  * to the page allocator, no bootmem metadata is updated because it is gone.
 154  */
 155 void __init free_bootmem_late(unsigned long addr, unsigned long size)
 156 {
 157         unsigned long cursor, end;
 158
 159         kmemleak_free_part(__va(addr), size);
 160
 161         cursor = PFN_UP(addr);
 162         end = PFN_DOWN(addr + size);
 163
 164         for (; cursor < end; cursor++) {
 165                 __free_pages_bootmem(pfn_to_page(cursor), 0);
 166                 totalram_pages++;
 167         }
 168 }
 169
 170 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 171 {
 172         int aligned;
 173         struct page *page;
 174         unsigned long start, end, pages, count = 0;
 175
 176         if (!bdata->node_bootmem_map)
 177                 return 0;
 178
 179         start = bdata->node_min_pfn;
 180         end = bdata->node_low_pfn;
 181
 182         /*
 183          * If the start is aligned to the machines wordsize, we might
 184          * be able to free pages in bulks of that order.
 185          */
 186         aligned = !(start & (BITS_PER_LONG - 1));
 187
 188         bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
 189                 bdata - bootmem_node_data, start, end, aligned);
 190
 191         while (start < end) {
 192                 unsigned long *map, idx, vec;
 193
 194                 map = bdata->node_bootmem_map;
 195                 idx = start - bdata->node_min_pfn;
 196                 vec = ~map[idx / BITS_PER_LONG];
 197
 198                 if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
 199                         int order = ilog2(BITS_PER_LONG);
 200
 201                         __free_pages_bootmem(pfn_to_page(start), order);
 202                         count += BITS_PER_LONG;
 203                 } else {
 204                         unsigned long off = 0;
 205
 206                         while (vec && off < BITS_PER_LONG) {
 207                                 if (vec & 1) {
 208                                         page = pfn_to_page(start + off);
 209                                         __free_pages_bootmem(page, 0);
 210                                         count++;
 211                                 }
 212                                 vec >>= 1;
 213                                 off++;
 214                         }
 215                 }
 216                 start += BITS_PER_LONG;
 217         }
 218
 219         page = virt_to_page(bdata->node_bootmem_map);
 220         pages = bdata->node_low_pfn - bdata->node_min_pfn;
 221         pages = bootmem_bootmap_pages(pages);
 222         count += pages;
 223         while (pages--)
 224                 __free_pages_bootmem(page++, 0);
 225
 226         bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
 227
 228         return count;
 229 }
 230
 231 /**
 232  * free_all_bootmem_node - release a node's free pages to the buddy allocator
 233  * @pgdat: node to be released
 234  *
 235  * Returns the number of pages actually released.
 236  */
 237 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
 238 {
 239         register_page_bootmem_info_node(pgdat);
 240         return free_all_bootmem_core(pgdat->bdata);
 241 }
 242
 243 /**
 244  * free_all_bootmem - release free pages to the buddy allocator
 245  *
 246  * Returns the number of pages actually released.
 247  */
 248 unsigned long __init free_all_bootmem(void)
 249 {
 250         return free_all_bootmem_core(NODE_DATA(0)->bdata);
 251 }
 252
 253 static void __init __free(bootmem_data_t *bdata,
 254                         unsigned long sidx, unsigned long eidx)
 255 {
 256         unsigned long idx;
 257
 258         bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
 259                 sidx + bdata->node_min_pfn,
 260                 eidx + bdata->node_min_pfn);
 261
 262         if (bdata->hint_idx > sidx)
 263                 bdata->hint_idx = sidx;
 264
 265         for (idx = sidx; idx < eidx; idx++)
 266                 if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
 267                         BUG();
 268 }
 269
 270 static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
 271                         unsigned long eidx, int flags)
 272 {
 273         unsigned long idx;
 274         int exclusive = flags & BOOTMEM_EXCLUSIVE;
 275
 276         bdebug("nid=%td start=%lx end=%lx flags=%x\n",
 277                 bdata - bootmem_node_data,
 278                 sidx + bdata->node_min_pfn,
 279                 eidx + bdata->node_min_pfn,
 280                 flags);
 281
 282         for (idx = sidx; idx < eidx; idx++)
 283                 if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
 284                         if (exclusive) {
 285                                 __free(bdata, sidx, idx);
 286                                 return -EBUSY;
 287                         }
 288                         bdebug("silent double reserve of PFN %lx\n",
 289                                 idx + bdata->node_min_pfn);
 290                 }
 291         return 0;
 292 }
 293
 294 static int __init mark_bootmem_node(bootmem_data_t *bdata,
 295                                 unsigned long start, unsigned long end,
 296                                 int reserve, int flags)
 297 {
 298         unsigned long sidx, eidx;
 299
 300         bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
 301                 bdata - bootmem_node_data, start, end, reserve, flags);
 302
 303         BUG_ON(start < bdata->node_min_pfn);
 304         BUG_ON(end > bdata->node_low_pfn);
 305
 306         sidx = start - bdata->node_min_pfn;
 307         eidx = end - bdata->node_min_pfn;
 308
 309         if (reserve)
 310                 return __reserve(bdata, sidx, eidx, flags);
 311         else
 312                 __free(bdata, sidx, eidx);
 313         return 0;
 314 }
 315
 316 static int __init mark_bootmem(unsigned long start, unsigned long end,
 317                                 int reserve, int flags)
 318 {
 319         unsigned long pos;
 320         bootmem_data_t *bdata;
 321
 322         pos = start;
 323         list_for_each_entry(bdata, &bdata_list, list) {
 324                 int err;
 325                 unsigned long max;
 326
 327                 if (pos < bdata->node_min_pfn ||
 328                     pos >= bdata->node_low_pfn) {
 329                         BUG_ON(pos != start);
 330                         continue;
 331                 }
 332
 333                 max = min(bdata->node_low_pfn, end);
 334
 335                 err = mark_bootmem_node(bdata, pos, max, reserve, flags);
 336                 if (reserve && err) {
 337                         mark_bootmem(start, pos, 0, 0);
 338                         return err;
 339                 }
 340
 341                 if (max == end)
 342                         return 0;
 343                 pos = bdata->node_low_pfn;
 344         }
 345         BUG();
 346 }
 347
 348 /**
 349  * free_bootmem_node - mark a page range as usable
 350  * @pgdat: node the range resides on
 351  * @physaddr: starting address of the range
 352  * @size: size of the range in bytes
 353  *
 354  * Partial pages will be considered reserved and left as they are.
 355  *
 356  * The range must reside completely on the specified node.
 357  */
 358 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 359                               unsigned long size)
 360 {
 361         unsigned long start, end;
 362
 363         kmemleak_free_part(__va(physaddr), size);
 364
 365         start = PFN_UP(physaddr);
 366         end = PFN_DOWN(physaddr + size);
 367
 368         mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
 369 }
 370
 371 /**
 372  * free_bootmem - mark a page range as usable
 373  * @addr: starting address of the range
 374  * @size: size of the range in bytes
 375  *
 376  * Partial pages will be considered reserved and left as they are.
 377  *
 378  * The range must be contiguous but may span node boundaries.
 379  */
 380 void __init free_bootmem(unsigned long addr, unsigned long size)
 381 {
 382         unsigned long start, end;
 383
 384         kmemleak_free_part(__va(addr), size);
 385
 386         start = PFN_UP(addr);
 387         end = PFN_DOWN(addr + size);
 388
 389         mark_bootmem(start, end, 0, 0);
 390 }
 391
 392 /**
 393  * reserve_bootmem_node - mark a page range as reserved
 394  * @pgdat: node the range resides on
 395  * @physaddr: starting address of the range
 396  * @size: size of the range in bytes
 397  * @flags: reservation flags (see linux/bootmem.h)
 398  *
 399  * Partial pages will be reserved.
 400  *
 401  * The range must reside completely on the specified node.
 402  */
 403 int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 404                                  unsigned long size, int flags)
 405 {
 406         unsigned long start, end;
 407
 408         start = PFN_DOWN(physaddr);
 409         end = PFN_UP(physaddr + size);
 410
 411         return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
 412 }
 413
 414 /**
 415  * reserve_bootmem - mark a page range as usable
 416  * @addr: starting address of the range
 417  * @size: size of the range in bytes
 418  * @flags: reservation flags (see linux/bootmem.h)
 419  *
 420  * Partial pages will be reserved.
 421  *
 422  * The range must be contiguous but may span node boundaries.
 423  */
 424 int __init reserve_bootmem(unsigned long addr, unsigned long size,
 425                             int flags)
 426 {
 427         unsigned long start, end;
 428
 429         start = PFN_DOWN(addr);
 430         end = PFN_UP(addr + size);
 431
 432         return mark_bootmem(start, end, 1, flags);
 433 }
 434
 435 static unsigned long __init align_idx(struct bootmem_data *bdata,
 436                                       unsigned long idx, unsigned long step)
 437 {
 438         unsigned long base = bdata->node_min_pfn;
 439
 440         /*
 441          * Align the index with respect to the node start so that the
 442          * combination of both satisfies the requested alignment.
 443          */
 444
 445         return ALIGN(base + idx, step) - base;
 446 }
 447
 448 static unsigned long __init align_off(struct bootmem_data *bdata,
 449                                       unsigned long off, unsigned long align)
 450 {
 451         unsigned long base = PFN_PHYS(bdata->node_min_pfn);
 452
 453         /* Same as align_idx for byte offsets */
 454
 455         return ALIGN(base + off, align) - base;
 456 }
 457
 458 static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
 459                                         unsigned long size, unsigned long align,
 460                                         unsigned long goal, unsigned long limit)
 461 {
 462         unsigned long fallback = 0;
 463         unsigned long min, max, start, sidx, midx, step;
 464
 465         bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
 466                 bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
 467                 align, goal, limit);
 468
 469         BUG_ON(!size);
 470         BUG_ON(align & (align - 1));
 471         BUG_ON(limit && goal + size > limit);
 472
 473         if (!bdata->node_bootmem_map)
 474                 return NULL;
 475
 476         min = bdata->node_min_pfn;
 477         max = bdata->node_low_pfn;
 478
 479         goal >>= PAGE_SHIFT;
 480         limit >>= PAGE_SHIFT;
 481
 482         if (limit && max > limit)
 483                 max = limit;
 484         if (max <= min)
 485                 return NULL;
 486
 487         step = max(align >> PAGE_SHIFT, 1UL);
 488
 489         if (goal && min < goal && goal < max)
 490                 start = ALIGN(goal, step);
 491         else
 492                 start = ALIGN(min, step);
 493
 494         sidx = start - bdata->node_min_pfn;
 495         midx = max - bdata->node_min_pfn;
 496
 497         if (bdata->hint_idx > sidx) {
 498                 /*
 499                  * Handle the valid case of sidx being zero and still
 500                  * catch the fallback below.
 501                  */
 502                 fallback = sidx + 1;
 503                 sidx = align_idx(bdata, bdata->hint_idx, step);
 504         }
 505
 506         while (1) {
 507                 int merge;
 508                 void *region;
 509                 unsigned long eidx, i, start_off, end_off;
 510 find_block:
 511                 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
 512                 sidx = align_idx(bdata, sidx, step);
 513                 eidx = sidx + PFN_UP(size);
 514
 515                 if (sidx >= midx || eidx > midx)
 516                         break;
 517
 518                 for (i = sidx; i < eidx; i++)
 519                         if (test_bit(i, bdata->node_bootmem_map)) {
 520                                 sidx = align_idx(bdata, i, step);
 521                                 if (sidx == i)
 522                                         sidx += step;
 523                                 goto find_block;
 524                         }
 525
 526                 if (bdata->last_end_off & (PAGE_SIZE - 1) &&
 527                                 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
 528                         start_off = align_off(bdata, bdata->last_end_off, align);
 529                 else
 530                         start_off = PFN_PHYS(sidx);
 531
 532                 merge = PFN_DOWN(start_off) < sidx;
 533                 end_off = start_off + size;
 534
 535                 bdata->last_end_off = end_off;
 536                 bdata->hint_idx = PFN_UP(end_off);
 537
 538                 /*
 539                  * Reserve the area now:
 540                  */
 541                 if (__reserve(bdata, PFN_DOWN(start_off) + merge,
 542                                 PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
 543                         BUG();
 544
 545                 region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
 546                                 start_off);
 547                 memset(region, 0, size);
 548                 /*
 549                  * The min_count is set to 0 so that bootmem allocated blocks
 550                  * are never reported as leaks.
 551                  */
 552                 kmemleak_alloc(region, size, 0, 0);
 553                 return region;
 554         }
 555
 556         if (fallback) {
 557                 sidx = align_idx(bdata, fallback - 1, step);
 558                 fallback = 0;
 559                 goto find_block;
 560         }
 561
 562         return NULL;
 563 }
 564
 565 static void * __init alloc_arch_preferred_bootmem(bootmem_data_t *bdata,
 566                                         unsigned long size, unsigned long align,
 567                                         unsigned long goal, unsigned long limit)
 568 {
 569         if (WARN_ON_ONCE(slab_is_available()))
 570                 return kzalloc(size, GFP_NOWAIT);
 571
 572 #ifdef CONFIG_HAVE_ARCH_BOOTMEM
 573         {
 574                 bootmem_data_t *p_bdata;
 575
 576                 p_bdata = bootmem_arch_preferred_node(bdata, size, align,
 577                                                         goal, limit);
 578                 if (p_bdata)
 579                         return alloc_bootmem_core(p_bdata, size, align,
 580                                                         goal, limit);
 581         }
 582 #endif
 583         return NULL;
 584 }
 585
 586 static void * __init ___alloc_bootmem_nopanic(unsigned long size,
 587                                         unsigned long align,
 588                                         unsigned long goal,
 589                                         unsigned long limit)
 590 {
 591         bootmem_data_t *bdata;
 592         void *region;
 593
 594 restart:
 595         region = alloc_arch_preferred_bootmem(NULL, size, align, goal, limit);
 596         if (region)
 597                 return region;
 598
 599         list_for_each_entry(bdata, &bdata_list, list) {
 600                 if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
 601                         continue;
 602                 if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
 603                         break;
 604
 605                 region = alloc_bootmem_core(bdata, size, align, goal, limit);
 606                 if (region)
 607                         return region;
 608         }
 609
 610         if (goal) {
 611                 goal = 0;
 612                 goto restart;
 613         }
 614
 615         return NULL;
 616 }
 617
 618 /**
 619  * __alloc_bootmem_nopanic - allocate boot memory without panicking
 620  * @size: size of the request in bytes
 621  * @align: alignment of the region
 622  * @goal: preferred starting address of the region
 623  *
 624  * The goal is dropped if it can not be satisfied and the allocation will
 625  * fall back to memory below @goal.
 626  *
 627  * Allocation may happen on any node in the system.
 628  *
 629  * Returns NULL on failure.
 630  */
 631 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
 632                                         unsigned long goal)
 633 {
 634         return ___alloc_bootmem_nopanic(size, align, goal, 0);
 635 }
 636
 637 static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
 638                                         unsigned long goal, unsigned long limit)
 639 {
 640         void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
 641
 642         if (mem)
 643                 return mem;
 644         /*
 645          * Whoops, we cannot satisfy the allocation request.
 646          */
 647         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 648         panic("Out of memory");
 649         return NULL;
 650 }
 651
 652 /**
 653  * __alloc_bootmem - allocate boot memory
 654  * @size: size of the request in bytes
 655  * @align: alignment of the region
 656  * @goal: preferred starting address of the region
 657  *
 658  * The goal is dropped if it can not be satisfied and the allocation will
 659  * fall back to memory below @goal.
 660  *
 661  * Allocation may happen on any node in the system.
 662  *
 663  * The function panics if the request can not be satisfied.
 664  */
 665 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
 666                               unsigned long goal)
 667 {
 668         return ___alloc_bootmem(size, align, goal, 0);
 669 }
 670
 671 static void * __init ___alloc_bootmem_node(bootmem_data_t *bdata,
 672                                 unsigned long size, unsigned long align,
 673                                 unsigned long goal, unsigned long limit)
 674 {
 675         void *ptr;
 676
 677         ptr = alloc_arch_preferred_bootmem(bdata, size, align, goal, limit);
 678         if (ptr)
 679                 return ptr;
 680
 681         ptr = alloc_bootmem_core(bdata, size, align, goal, limit);
 682         if (ptr)
 683                 return ptr;
 684
 685         return ___alloc_bootmem(size, align, goal, limit);
 686 }
 687
 688 /**
 689  * __alloc_bootmem_node - allocate boot memory from a specific node
 690  * @pgdat: node to allocate from
 691  * @size: size of the request in bytes
 692  * @align: alignment of the region
 693  * @goal: preferred starting address of the region
 694  *
 695  * The goal is dropped if it can not be satisfied and the allocation will
 696  * fall back to memory below @goal.
 697  *
 698  * Allocation may fall back to any node in the system if the specified node
 699  * can not hold the requested memory.
 700  *
 701  * The function panics if the request can not be satisfied.
 702  */
 703 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
 704                                    unsigned long align, unsigned long goal)
 705 {
 706         if (WARN_ON_ONCE(slab_is_available()))
 707                 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
 708
 709         return ___alloc_bootmem_node(pgdat->bdata, size, align, goal, 0);
 710 }
 711
 712 #ifdef CONFIG_SPARSEMEM
 713 /**
 714  * alloc_bootmem_section - allocate boot memory from a specific section
 715  * @size: size of the request in bytes
 716  * @section_nr: sparse map section to allocate from
 717  *
 718  * Return NULL on failure.
 719  */
 720 void * __init alloc_bootmem_section(unsigned long size,
 721                                     unsigned long section_nr)
 722 {
 723         bootmem_data_t *bdata;
 724         unsigned long pfn, goal, limit;
 725
 726         pfn = section_nr_to_pfn(section_nr);
 727         goal = pfn << PAGE_SHIFT;
 728         limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT;
 729         bdata = &bootmem_node_data[early_pfn_to_nid(pfn)];
 730
 731         return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit);
 732 }
 733 #endif
 734
 735 void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
 736                                    unsigned long align, unsigned long goal)
 737 {
 738         void *ptr;
 739
 740         if (WARN_ON_ONCE(slab_is_available()))
 741                 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
 742
 743         ptr = alloc_arch_preferred_bootmem(pgdat->bdata, size, align, goal, 0);
 744         if (ptr)
 745                 return ptr;
 746
 747         ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 748         if (ptr)
 749                 return ptr;
 750
 751         return __alloc_bootmem_nopanic(size, align, goal);
 752 }
 753
 754 #ifndef ARCH_LOW_ADDRESS_LIMIT
 755 #define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL
 756 #endif
 757
 758 /**
 759  * __alloc_bootmem_low - allocate low boot memory
 760  * @size: size of the request in bytes
 761  * @align: alignment of the region
 762  * @goal: preferred starting address of the region
 763  *
 764  * The goal is dropped if it can not be satisfied and the allocation will
 765  * fall back to memory below @goal.
 766  *
 767  * Allocation may happen on any node in the system.
 768  *
 769  * The function panics if the request can not be satisfied.
 770  */
 771 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
 772                                   unsigned long goal)
 773 {
 774         return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
 775 }
 776
 777 /**
 778  * __alloc_bootmem_low_node - allocate low boot memory from a specific node
 779  * @pgdat: node to allocate from
 780  * @size: size of the request in bytes
 781  * @align: alignment of the region
 782  * @goal: preferred starting address of the region
 783  *
 784  * The goal is dropped if it can not be satisfied and the allocation will
 785  * fall back to memory below @goal.
 786  *
 787  * Allocation may fall back to any node in the system if the specified node
 788  * can not hold the requested memory.
 789  *
 790  * The function panics if the request can not be satisfied.
 791  */
 792 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
 793                                        unsigned long align, unsigned long goal)
 794 {
 795         if (WARN_ON_ONCE(slab_is_available()))
 796                 return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
 797
 798         return ___alloc_bootmem_node(pgdat->bdata, size, align,
 799                                 goal, ARCH_LOW_ADDRESS_LIMIT);
 800 }