mm/bootmem.c

   1 /*
   2  *  linux/mm/bootmem.c
   3  *
   4  *  Copyright (C) 1999 Ingo Molnar
   5  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
   6  *
   7  *  simple boot-time physical memory area allocator and
   8  *  free memory collector. It's used to deal with reserved
   9  *  system memory and memory holes as well.
  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 /*
  23  * Access to this subsystem has to be serialized externally. (this is
  24  * true for the boot process anyway)
  25  */
  26 unsigned long max_low_pfn;
  27 unsigned long min_low_pfn;
  28 unsigned long max_pfn;
  29
  30 static LIST_HEAD(bdata_list);
  31 #ifdef CONFIG_CRASH_DUMP
  32 /*
  33  * If we have booted due to a crash, max_pfn will be a very low value. We need
  34  * to know the amount of memory that the previous kernel used.
  35  */
  36 unsigned long saved_max_pfn;
  37 #endif
  38
  39 /* return the number of _pages_ that will be allocated for the boot bitmap */
  40 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
  41 {
  42         unsigned long mapsize;
  43
  44         mapsize = (pages+7)/8;
  45         mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
  46         mapsize >>= PAGE_SHIFT;
  47
  48         return mapsize;
  49 }
  50
  51 /*
  52  * link bdata in order
  53  */
  54 static void __init link_bootmem(bootmem_data_t *bdata)
  55 {
  56         bootmem_data_t *ent;
  57
  58         if (list_empty(&bdata_list)) {
  59                 list_add(&bdata->list, &bdata_list);
  60                 return;
  61         }
  62         /* insert in order */
  63         list_for_each_entry(ent, &bdata_list, list) {
  64                 if (bdata->node_boot_start < ent->node_boot_start) {
  65                         list_add_tail(&bdata->list, &ent->list);
  66                         return;
  67                 }
  68         }
  69         list_add_tail(&bdata->list, &bdata_list);
  70 }
  71
  72 /*
  73  * Given an initialised bdata, it returns the size of the boot bitmap
  74  */
  75 static unsigned long __init get_mapsize(bootmem_data_t *bdata)
  76 {
  77         unsigned long mapsize;
  78         unsigned long start = PFN_DOWN(bdata->node_boot_start);
  79         unsigned long end = bdata->node_low_pfn;
  80
  81         mapsize = ((end - start) + 7) / 8;
  82         return ALIGN(mapsize, sizeof(long));
  83 }
  84
  85 /*
  86  * Called once to set up the allocator itself.
  87  */
  88 static unsigned long __init init_bootmem_core(pg_data_t *pgdat,
  89         unsigned long mapstart, unsigned long start, unsigned long end)
  90 {
  91         bootmem_data_t *bdata = pgdat->bdata;
  92         unsigned long mapsize;
  93
  94         bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
  95         bdata->node_boot_start = PFN_PHYS(start);
  96         bdata->node_low_pfn = end;
  97         link_bootmem(bdata);
  98
  99         /*
 100          * Initially all pages are reserved - setup_arch() has to
 101          * register free RAM areas explicitly.
 102          */
 103         mapsize = get_mapsize(bdata);
 104         memset(bdata->node_bootmem_map, 0xff, mapsize);
 105
 106         return mapsize;
 107 }
 108
 109 /*
 110  * Marks a particular physical memory range as unallocatable. Usable RAM
 111  * might be used for boot-time allocations - or it might get added
 112  * to the free page pool later on.
 113  */
 114 static int __init can_reserve_bootmem_core(bootmem_data_t *bdata,
 115                         unsigned long addr, unsigned long size, int flags)
 116 {
 117         unsigned long sidx, eidx;
 118         unsigned long i;
 119
 120         BUG_ON(!size);
 121
 122         /* out of range, don't hold other */
 123         if (addr + size < bdata->node_boot_start ||
 124                 PFN_DOWN(addr) > bdata->node_low_pfn)
 125                 return 0;
 126
 127         /*
 128          * Round up to index to the range.
 129          */
 130         if (addr > bdata->node_boot_start)
 131                 sidx= PFN_DOWN(addr - bdata->node_boot_start);
 132         else
 133                 sidx = 0;
 134
 135         eidx = PFN_UP(addr + size - bdata->node_boot_start);
 136         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 137                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 138
 139         for (i = sidx; i < eidx; i++) {
 140                 if (test_bit(i, bdata->node_bootmem_map)) {
 141                         if (flags & BOOTMEM_EXCLUSIVE)
 142                                 return -EBUSY;
 143                 }
 144         }
 145
 146         return 0;
 147
 148 }
 149
 150 static void __init reserve_bootmem_core(bootmem_data_t *bdata,
 151                         unsigned long addr, unsigned long size, int flags)
 152 {
 153         unsigned long sidx, eidx;
 154         unsigned long i;
 155
 156         BUG_ON(!size);
 157
 158         /* out of range */
 159         if (addr + size < bdata->node_boot_start ||
 160                 PFN_DOWN(addr) > bdata->node_low_pfn)
 161                 return;
 162
 163         /*
 164          * Round up to index to the range.
 165          */
 166         if (addr > bdata->node_boot_start)
 167                 sidx= PFN_DOWN(addr - bdata->node_boot_start);
 168         else
 169                 sidx = 0;
 170
 171         eidx = PFN_UP(addr + size - bdata->node_boot_start);
 172         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 173                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 174
 175         for (i = sidx; i < eidx; i++) {
 176                 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
 177 #ifdef CONFIG_DEBUG_BOOTMEM
 178                         printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
 179 #endif
 180                 }
 181         }
 182 }
 183
 184 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
 185                                      unsigned long size)
 186 {
 187         unsigned long sidx, eidx;
 188         unsigned long i;
 189
 190         BUG_ON(!size);
 191
 192         /* out range */
 193         if (addr + size < bdata->node_boot_start ||
 194                 PFN_DOWN(addr) > bdata->node_low_pfn)
 195                 return;
 196         /*
 197          * round down end of usable mem, partially free pages are
 198          * considered reserved.
 199          */
 200
 201         if (addr >= bdata->node_boot_start && addr < bdata->last_success)
 202                 bdata->last_success = addr;
 203
 204         /*
 205          * Round up to index to the range.
 206          */
 207         if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
 208                 sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
 209         else
 210                 sidx = 0;
 211
 212         eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
 213         if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
 214                 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 215
 216         for (i = sidx; i < eidx; i++) {
 217                 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
 218                         BUG();
 219         }
 220 }
 221
 222 /*
 223  * We 'merge' subsequent allocations to save space. We might 'lose'
 224  * some fraction of a page if allocations cannot be satisfied due to
 225  * size constraints on boxes where there is physical RAM space
 226  * fragmentation - in these cases (mostly large memory boxes) this
 227  * is not a problem.
 228  *
 229  * On low memory boxes we get it right in 100% of the cases.
 230  *
 231  * alignment has to be a power of 2 value.
 232  *
 233  * NOTE:  This function is _not_ reentrant.
 234  */
 235 void * __init
 236 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
 237               unsigned long align, unsigned long goal, unsigned long limit)
 238 {
 239         unsigned long areasize, preferred;
 240         unsigned long i, start = 0, incr, eidx, end_pfn;
 241         void *ret;
 242         unsigned long node_boot_start;
 243         void *node_bootmem_map;
 244
 245         if (!size) {
 246                 printk("__alloc_bootmem_core(): zero-sized request\n");
 247                 BUG();
 248         }
 249         BUG_ON(align & (align-1));
 250
 251         /* on nodes without memory - bootmem_map is NULL */
 252         if (!bdata->node_bootmem_map)
 253                 return NULL;
 254
 255         /* bdata->node_boot_start is supposed to be (12+6)bits alignment on x86_64 ? */
 256         node_boot_start = bdata->node_boot_start;
 257         node_bootmem_map = bdata->node_bootmem_map;
 258         if (align) {
 259                 node_boot_start = ALIGN(bdata->node_boot_start, align);
 260                 if (node_boot_start > bdata->node_boot_start)
 261                         node_bootmem_map = (unsigned long *)bdata->node_bootmem_map +
 262                             PFN_DOWN(node_boot_start - bdata->node_boot_start)/BITS_PER_LONG;
 263         }
 264
 265         if (limit && node_boot_start >= limit)
 266                 return NULL;
 267
 268         end_pfn = bdata->node_low_pfn;
 269         limit = PFN_DOWN(limit);
 270         if (limit && end_pfn > limit)
 271                 end_pfn = limit;
 272
 273         eidx = end_pfn - PFN_DOWN(node_boot_start);
 274
 275         /*
 276          * We try to allocate bootmem pages above 'goal'
 277          * first, then we try to allocate lower pages.
 278          */
 279         preferred = 0;
 280         if (goal && PFN_DOWN(goal) < end_pfn) {
 281                 if (goal > node_boot_start)
 282                         preferred = goal - node_boot_start;
 283
 284                 if (bdata->last_success > node_boot_start &&
 285                         bdata->last_success - node_boot_start >= preferred)
 286                         if (!limit || (limit && limit > bdata->last_success))
 287                                 preferred = bdata->last_success - node_boot_start;
 288         }
 289
 290         preferred = PFN_DOWN(ALIGN(preferred, align));
 291         areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
 292         incr = align >> PAGE_SHIFT ? : 1;
 293
 294 restart_scan:
 295         for (i = preferred; i < eidx;) {
 296                 unsigned long j;
 297
 298                 i = find_next_zero_bit(node_bootmem_map, eidx, i);
 299                 i = ALIGN(i, incr);
 300                 if (i >= eidx)
 301                         break;
 302                 if (test_bit(i, node_bootmem_map)) {
 303                         i += incr;
 304                         continue;
 305                 }
 306                 for (j = i + 1; j < i + areasize; ++j) {
 307                         if (j >= eidx)
 308                                 goto fail_block;
 309                         if (test_bit(j, node_bootmem_map))
 310                                 goto fail_block;
 311                 }
 312                 start = i;
 313                 goto found;
 314         fail_block:
 315                 i = ALIGN(j, incr);
 316                 if (i == j)
 317                         i += incr;
 318         }
 319
 320         if (preferred > 0) {
 321                 preferred = 0;
 322                 goto restart_scan;
 323         }
 324         return NULL;
 325
 326 found:
 327         bdata->last_success = PFN_PHYS(start) + node_boot_start;
 328         BUG_ON(start >= eidx);
 329
 330         /*
 331          * Is the next page of the previous allocation-end the start
 332          * of this allocation's buffer? If yes then we can 'merge'
 333          * the previous partial page with this allocation.
 334          */
 335         if (align < PAGE_SIZE &&
 336             bdata->last_offset && bdata->last_pos+1 == start) {
 337                 unsigned long offset, remaining_size;
 338                 offset = ALIGN(bdata->last_offset, align);
 339                 BUG_ON(offset > PAGE_SIZE);
 340                 remaining_size = PAGE_SIZE - offset;
 341                 if (size < remaining_size) {
 342                         areasize = 0;
 343                         /* last_pos unchanged */
 344                         bdata->last_offset = offset + size;
 345                         ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
 346                                            offset + node_boot_start);
 347                 } else {
 348                         remaining_size = size - remaining_size;
 349                         areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
 350                         ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
 351                                            offset + node_boot_start);
 352                         bdata->last_pos = start + areasize - 1;
 353                         bdata->last_offset = remaining_size;
 354                 }
 355                 bdata->last_offset &= ~PAGE_MASK;
 356         } else {
 357                 bdata->last_pos = start + areasize - 1;
 358                 bdata->last_offset = size & ~PAGE_MASK;
 359                 ret = phys_to_virt(start * PAGE_SIZE + node_boot_start);
 360         }
 361
 362         /*
 363          * Reserve the area now:
 364          */
 365         for (i = start; i < start + areasize; i++)
 366                 if (unlikely(test_and_set_bit(i, node_bootmem_map)))
 367                         BUG();
 368         memset(ret, 0, size);
 369         return ret;
 370 }
 371
 372 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
 373 {
 374         struct page *page;
 375         unsigned long pfn;
 376         bootmem_data_t *bdata = pgdat->bdata;
 377         unsigned long i, count, total = 0;
 378         unsigned long idx;
 379         unsigned long *map;
 380         int gofast = 0;
 381
 382         BUG_ON(!bdata->node_bootmem_map);
 383
 384         count = 0;
 385         /* first extant page of the node */
 386         pfn = PFN_DOWN(bdata->node_boot_start);
 387         idx = bdata->node_low_pfn - pfn;
 388         map = bdata->node_bootmem_map;
 389         /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
 390         if (bdata->node_boot_start == 0 ||
 391             ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
 392                 gofast = 1;
 393         for (i = 0; i < idx; ) {
 394                 unsigned long v = ~map[i / BITS_PER_LONG];
 395
 396                 if (gofast && v == ~0UL) {
 397                         int order;
 398
 399                         page = pfn_to_page(pfn);
 400                         count += BITS_PER_LONG;
 401                         order = ffs(BITS_PER_LONG) - 1;
 402                         __free_pages_bootmem(page, order);
 403                         i += BITS_PER_LONG;
 404                         page += BITS_PER_LONG;
 405                 } else if (v) {
 406                         unsigned long m;
 407
 408                         page = pfn_to_page(pfn);
 409                         for (m = 1; m && i < idx; m<<=1, page++, i++) {
 410                                 if (v & m) {
 411                                         count++;
 412                                         __free_pages_bootmem(page, 0);
 413                                 }
 414                         }
 415                 } else {
 416                         i += BITS_PER_LONG;
 417                 }
 418                 pfn += BITS_PER_LONG;
 419         }
 420         total += count;
 421
 422         /*
 423          * Now free the allocator bitmap itself, it's not
 424          * needed anymore:
 425          */
 426         page = virt_to_page(bdata->node_bootmem_map);
 427         count = 0;
 428         idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
 429         for (i = 0; i < idx; i++, page++) {
 430                 __free_pages_bootmem(page, 0);
 431                 count++;
 432         }
 433         total += count;
 434         bdata->node_bootmem_map = NULL;
 435
 436         return total;
 437 }
 438
 439 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
 440                                 unsigned long startpfn, unsigned long endpfn)
 441 {
 442         return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
 443 }
 444
 445 void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 446                                  unsigned long size, int flags)
 447 {
 448         int ret;
 449
 450         ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 451         if (ret < 0)
 452                 return;
 453         reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 454 }
 455
 456 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 457                               unsigned long size)
 458 {
 459         free_bootmem_core(pgdat->bdata, physaddr, size);
 460 }
 461
 462 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
 463 {
 464         return free_all_bootmem_core(pgdat);
 465 }
 466
 467 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
 468 {
 469         max_low_pfn = pages;
 470         min_low_pfn = start;
 471         return init_bootmem_core(NODE_DATA(0), start, 0, pages);
 472 }
 473
 474 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 475 int __init reserve_bootmem(unsigned long addr, unsigned long size,
 476                             int flags)
 477 {
 478         bootmem_data_t *bdata;
 479         int ret;
 480
 481         list_for_each_entry(bdata, &bdata_list, list) {
 482                 ret = can_reserve_bootmem_core(bdata, addr, size, flags);
 483                 if (ret < 0)
 484                         return ret;
 485         }
 486         list_for_each_entry(bdata, &bdata_list, list)
 487                 reserve_bootmem_core(bdata, addr, size, flags);
 488
 489         return 0;
 490 }
 491 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
 492
 493 void __init free_bootmem(unsigned long addr, unsigned long size)
 494 {
 495         bootmem_data_t *bdata;
 496         list_for_each_entry(bdata, &bdata_list, list)
 497                 free_bootmem_core(bdata, addr, size);
 498 }
 499
 500 unsigned long __init free_all_bootmem(void)
 501 {
 502         return free_all_bootmem_core(NODE_DATA(0));
 503 }
 504
 505 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
 506                                       unsigned long goal)
 507 {
 508         bootmem_data_t *bdata;
 509         void *ptr;
 510
 511         list_for_each_entry(bdata, &bdata_list, list) {
 512                 ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
 513                 if (ptr)
 514                         return ptr;
 515         }
 516         return NULL;
 517 }
 518
 519 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
 520                               unsigned long goal)
 521 {
 522         void *mem = __alloc_bootmem_nopanic(size,align,goal);
 523
 524         if (mem)
 525                 return mem;
 526         /*
 527          * Whoops, we cannot satisfy the allocation request.
 528          */
 529         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 530         panic("Out of memory");
 531         return NULL;
 532 }
 533
 534
 535 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
 536                                    unsigned long align, unsigned long goal)
 537 {
 538         void *ptr;
 539
 540         ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 541         if (ptr)
 542                 return ptr;
 543
 544         return __alloc_bootmem(size, align, goal);
 545 }
 546
 547 #ifndef ARCH_LOW_ADDRESS_LIMIT
 548 #define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL
 549 #endif
 550
 551 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
 552                                   unsigned long goal)
 553 {
 554         bootmem_data_t *bdata;
 555         void *ptr;
 556
 557         list_for_each_entry(bdata, &bdata_list, list) {
 558                 ptr = __alloc_bootmem_core(bdata, size, align, goal,
 559                                                 ARCH_LOW_ADDRESS_LIMIT);
 560                 if (ptr)
 561                         return ptr;
 562         }
 563
 564         /*
 565          * Whoops, we cannot satisfy the allocation request.
 566          */
 567         printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
 568         panic("Out of low memory");
 569         return NULL;
 570 }
 571
 572 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
 573                                        unsigned long align, unsigned long goal)
 574 {
 575         return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
 576                                     ARCH_LOW_ADDRESS_LIMIT);
 577 }