mm/sparse.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sparse memory mappings.
   4  */
   5 #include <linux/mm.h>
   6 #include <linux/slab.h>
   7 #include <linux/mmzone.h>
   8 #include <linux/bootmem.h>
   9 #include <linux/compiler.h>
  10 #include <linux/highmem.h>
  11 #include <linux/export.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/vmalloc.h>
  14
  15 #include "internal.h"
  16 #include <asm/dma.h>
  17 #include <asm/pgalloc.h>
  18 #include <asm/pgtable.h>
  19
  20 /*
  21  * Permanent SPARSEMEM data:
  22  *
  23  * 1) mem_section       - memory sections, mem_map's for valid memory
  24  */
  25 #ifdef CONFIG_SPARSEMEM_EXTREME
  26 struct mem_section **mem_section;
  27 #else
  28 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
  29         ____cacheline_internodealigned_in_smp;
  30 #endif
  31 EXPORT_SYMBOL(mem_section);
  32
  33 #ifdef NODE_NOT_IN_PAGE_FLAGS
  34 /*
  35  * If we did not store the node number in the page then we have to
  36  * do a lookup in the section_to_node_table in order to find which
  37  * node the page belongs to.
  38  */
  39 #if MAX_NUMNODES <= 256
  40 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  41 #else
  42 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  43 #endif
  44
  45 int page_to_nid(const struct page *page)
  46 {
  47         return section_to_node_table[page_to_section(page)];
  48 }
  49 EXPORT_SYMBOL(page_to_nid);
  50
  51 static void set_section_nid(unsigned long section_nr, int nid)
  52 {
  53         section_to_node_table[section_nr] = nid;
  54 }
  55 #else /* !NODE_NOT_IN_PAGE_FLAGS */
  56 static inline void set_section_nid(unsigned long section_nr, int nid)
  57 {
  58 }
  59 #endif
  60
  61 #ifdef CONFIG_SPARSEMEM_EXTREME
  62 static noinline struct mem_section __ref *sparse_index_alloc(int nid)
  63 {
  64         struct mem_section *section = NULL;
  65         unsigned long array_size = SECTIONS_PER_ROOT *
  66                                    sizeof(struct mem_section);
  67
  68         if (slab_is_available())
  69                 section = kzalloc_node(array_size, GFP_KERNEL, nid);
  70         else
  71                 section = memblock_virt_alloc_node(array_size, nid);
  72
  73         return section;
  74 }
  75
  76 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
  77 {
  78         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
  79         struct mem_section *section;
  80
  81         if (mem_section[root])
  82                 return -EEXIST;
  83
  84         section = sparse_index_alloc(nid);
  85         if (!section)
  86                 return -ENOMEM;
  87
  88         mem_section[root] = section;
  89
  90         return 0;
  91 }
  92 #else /* !SPARSEMEM_EXTREME */
  93 static inline int sparse_index_init(unsigned long section_nr, int nid)
  94 {
  95         return 0;
  96 }
  97 #endif
  98
  99 #ifdef CONFIG_SPARSEMEM_EXTREME
 100 int __section_nr(struct mem_section* ms)
 101 {
 102         unsigned long root_nr;
 103         struct mem_section *root = NULL;
 104
 105         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
 106                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 107                 if (!root)
 108                         continue;
 109
 110                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
 111                      break;
 112         }
 113
 114         VM_BUG_ON(!root);
 115
 116         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 117 }
 118 #else
 119 int __section_nr(struct mem_section* ms)
 120 {
 121         return (int)(ms - mem_section[0]);
 122 }
 123 #endif
 124
 125 /*
 126  * During early boot, before section_mem_map is used for an actual
 127  * mem_map, we use section_mem_map to store the section's NUMA
 128  * node.  This keeps us from having to use another data structure.  The
 129  * node information is cleared just before we store the real mem_map.
 130  */
 131 static inline unsigned long sparse_encode_early_nid(int nid)
 132 {
 133         return (nid << SECTION_NID_SHIFT);
 134 }
 135
 136 static inline int sparse_early_nid(struct mem_section *section)
 137 {
 138         return (section->section_mem_map >> SECTION_NID_SHIFT);
 139 }
 140
 141 /* Validate the physical addressing limitations of the model */
 142 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
 143                                                 unsigned long *end_pfn)
 144 {
 145         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
 146
 147         /*
 148          * Sanity checks - do not allow an architecture to pass
 149          * in larger pfns than the maximum scope of sparsemem:
 150          */
 151         if (*start_pfn > max_sparsemem_pfn) {
 152                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 153                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 154                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 155                 WARN_ON_ONCE(1);
 156                 *start_pfn = max_sparsemem_pfn;
 157                 *end_pfn = max_sparsemem_pfn;
 158         } else if (*end_pfn > max_sparsemem_pfn) {
 159                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 160                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 161                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 162                 WARN_ON_ONCE(1);
 163                 *end_pfn = max_sparsemem_pfn;
 164         }
 165 }
 166
 167 /*
 168  * There are a number of times that we loop over NR_MEM_SECTIONS,
 169  * looking for section_present() on each.  But, when we have very
 170  * large physical address spaces, NR_MEM_SECTIONS can also be
 171  * very large which makes the loops quite long.
 172  *
 173  * Keeping track of this gives us an easy way to break out of
 174  * those loops early.
 175  */
 176 int __highest_present_section_nr;
 177 static void section_mark_present(struct mem_section *ms)
 178 {
 179         int section_nr = __section_nr(ms);
 180
 181         if (section_nr > __highest_present_section_nr)
 182                 __highest_present_section_nr = section_nr;
 183
 184         ms->section_mem_map |= SECTION_MARKED_PRESENT;
 185 }
 186
 187 static inline int next_present_section_nr(int section_nr)
 188 {
 189         do {
 190                 section_nr++;
 191                 if (present_section_nr(section_nr))
 192                         return section_nr;
 193         } while ((section_nr < NR_MEM_SECTIONS) &&
 194                  (section_nr <= __highest_present_section_nr));
 195
 196         return -1;
 197 }
 198 #define for_each_present_section_nr(start, section_nr)          \
 199         for (section_nr = next_present_section_nr(start-1);     \
 200              ((section_nr >= 0) &&                              \
 201               (section_nr < NR_MEM_SECTIONS) &&                 \
 202               (section_nr <= __highest_present_section_nr));    \
 203              section_nr = next_present_section_nr(section_nr))
 204
 205 /* Record a memory area against a node. */
 206 void __init memory_present(int nid, unsigned long start, unsigned long end)
 207 {
 208         unsigned long pfn;
 209
 210 #ifdef CONFIG_SPARSEMEM_EXTREME
 211         if (unlikely(!mem_section)) {
 212                 unsigned long size, align;
 213
 214                 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
 215                 align = 1 << (INTERNODE_CACHE_SHIFT);
 216                 mem_section = memblock_virt_alloc(size, align);
 217         }
 218 #endif
 219
 220         start &= PAGE_SECTION_MASK;
 221         mminit_validate_memmodel_limits(&start, &end);
 222         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
 223                 unsigned long section = pfn_to_section_nr(pfn);
 224                 struct mem_section *ms;
 225
 226                 sparse_index_init(section, nid);
 227                 set_section_nid(section, nid);
 228
 229                 ms = __nr_to_section(section);
 230                 if (!ms->section_mem_map) {
 231                         ms->section_mem_map = sparse_encode_early_nid(nid) |
 232                                                         SECTION_IS_ONLINE;
 233                         section_mark_present(ms);
 234                 }
 235         }
 236 }
 237
 238 /*
 239  * Only used by the i386 NUMA architecures, but relatively
 240  * generic code.
 241  */
 242 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
 243                                                      unsigned long end_pfn)
 244 {
 245         unsigned long pfn;
 246         unsigned long nr_pages = 0;
 247
 248         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
 249         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 250                 if (nid != early_pfn_to_nid(pfn))
 251                         continue;
 252
 253                 if (pfn_present(pfn))
 254                         nr_pages += PAGES_PER_SECTION;
 255         }
 256
 257         return nr_pages * sizeof(struct page);
 258 }
 259
 260 /*
 261  * Subtle, we encode the real pfn into the mem_map such that
 262  * the identity pfn - section_mem_map will return the actual
 263  * physical page frame number.
 264  */
 265 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
 266 {
 267         return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
 268 }
 269
 270 /*
 271  * Decode mem_map from the coded memmap
 272  */
 273 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
 274 {
 275         /* mask off the extra low bits of information */
 276         coded_mem_map &= SECTION_MAP_MASK;
 277         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 278 }
 279
 280 static int __meminit sparse_init_one_section(struct mem_section *ms,
 281                 unsigned long pnum, struct page *mem_map,
 282                 unsigned long *pageblock_bitmap)
 283 {
 284         if (!present_section(ms))
 285                 return -EINVAL;
 286
 287         ms->section_mem_map &= ~SECTION_MAP_MASK;
 288         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 289                                                         SECTION_HAS_MEM_MAP;
 290         ms->pageblock_flags = pageblock_bitmap;
 291
 292         return 1;
 293 }
 294
 295 unsigned long usemap_size(void)
 296 {
 297         return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
 298 }
 299
 300 #ifdef CONFIG_MEMORY_HOTPLUG
 301 static unsigned long *__kmalloc_section_usemap(void)
 302 {
 303         return kmalloc(usemap_size(), GFP_KERNEL);
 304 }
 305 #endif /* CONFIG_MEMORY_HOTPLUG */
 306
 307 #ifdef CONFIG_MEMORY_HOTREMOVE
 308 static unsigned long * __init
 309 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 310                                          unsigned long size)
 311 {
 312         unsigned long goal, limit;
 313         unsigned long *p;
 314         int nid;
 315         /*
 316          * A page may contain usemaps for other sections preventing the
 317          * page being freed and making a section unremovable while
 318          * other sections referencing the usemap remain active. Similarly,
 319          * a pgdat can prevent a section being removed. If section A
 320          * contains a pgdat and section B contains the usemap, both
 321          * sections become inter-dependent. This allocates usemaps
 322          * from the same section as the pgdat where possible to avoid
 323          * this problem.
 324          */
 325         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
 326         limit = goal + (1UL << PA_SECTION_SHIFT);
 327         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 328 again:
 329         p = memblock_virt_alloc_try_nid_nopanic(size,
 330                                                 SMP_CACHE_BYTES, goal, limit,
 331                                                 nid);
 332         if (!p && limit) {
 333                 limit = 0;
 334                 goto again;
 335         }
 336         return p;
 337 }
 338
 339 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 340 {
 341         unsigned long usemap_snr, pgdat_snr;
 342         static unsigned long old_usemap_snr;
 343         static unsigned long old_pgdat_snr;
 344         struct pglist_data *pgdat = NODE_DATA(nid);
 345         int usemap_nid;
 346
 347         /* First call */
 348         if (!old_usemap_snr) {
 349                 old_usemap_snr = NR_MEM_SECTIONS;
 350                 old_pgdat_snr = NR_MEM_SECTIONS;
 351         }
 352
 353         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
 354         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 355         if (usemap_snr == pgdat_snr)
 356                 return;
 357
 358         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
 359                 /* skip redundant message */
 360                 return;
 361
 362         old_usemap_snr = usemap_snr;
 363         old_pgdat_snr = pgdat_snr;
 364
 365         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
 366         if (usemap_nid != nid) {
 367                 pr_info("node %d must be removed before remove section %ld\n",
 368                         nid, usemap_snr);
 369                 return;
 370         }
 371         /*
 372          * There is a circular dependency.
 373          * Some platforms allow un-removable section because they will just
 374          * gather other removable sections for dynamic partitioning.
 375          * Just notify un-removable section's number here.
 376          */
 377         pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
 378                 usemap_snr, pgdat_snr, nid);
 379 }
 380 #else
 381 static unsigned long * __init
 382 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 383                                          unsigned long size)
 384 {
 385         return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 386 }
 387
 388 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 389 {
 390 }
 391 #endif /* CONFIG_MEMORY_HOTREMOVE */
 392
 393 static void __init sparse_early_usemaps_alloc_node(void *data,
 394                                  unsigned long pnum_begin,
 395                                  unsigned long pnum_end,
 396                                  unsigned long usemap_count, int nodeid)
 397 {
 398         void *usemap;
 399         unsigned long pnum;
 400         unsigned long **usemap_map = (unsigned long **)data;
 401         int size = usemap_size();
 402
 403         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
 404                                                           size * usemap_count);
 405         if (!usemap) {
 406                 pr_warn("%s: allocation failed\n", __func__);
 407                 return;
 408         }
 409
 410         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 411                 if (!present_section_nr(pnum))
 412                         continue;
 413                 usemap_map[pnum] = usemap;
 414                 usemap += size;
 415                 check_usemap_section_nr(nodeid, usemap_map[pnum]);
 416         }
 417 }
 418
 419 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 420 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
 421                 struct vmem_altmap *altmap)
 422 {
 423         struct page *map;
 424         unsigned long size;
 425
 426         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
 427         if (map)
 428                 return map;
 429
 430         size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 431         map = memblock_virt_alloc_try_nid(size,
 432                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 433                                           BOOTMEM_ALLOC_ACCESSIBLE, nid);
 434         return map;
 435 }
 436 void __init sparse_mem_maps_populate_node(struct page **map_map,
 437                                           unsigned long pnum_begin,
 438                                           unsigned long pnum_end,
 439                                           unsigned long map_count, int nodeid)
 440 {
 441         void *map;
 442         unsigned long pnum;
 443         unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
 444
 445         map = alloc_remap(nodeid, size * map_count);
 446         if (map) {
 447                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 448                         if (!present_section_nr(pnum))
 449                                 continue;
 450                         map_map[pnum] = map;
 451                         map += size;
 452                 }
 453                 return;
 454         }
 455
 456         size = PAGE_ALIGN(size);
 457         map = memblock_virt_alloc_try_nid_raw(size * map_count,
 458                                               PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 459                                               BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
 460         if (map) {
 461                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 462                         if (!present_section_nr(pnum))
 463                                 continue;
 464                         map_map[pnum] = map;
 465                         map += size;
 466                 }
 467                 return;
 468         }
 469
 470         /* fallback */
 471         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 472                 struct mem_section *ms;
 473
 474                 if (!present_section_nr(pnum))
 475                         continue;
 476                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid, NULL);
 477                 if (map_map[pnum])
 478                         continue;
 479                 ms = __nr_to_section(pnum);
 480                 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
 481                        __func__);
 482                 ms->section_mem_map = 0;
 483         }
 484 }
 485 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 486
 487 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 488 static void __init sparse_early_mem_maps_alloc_node(void *data,
 489                                  unsigned long pnum_begin,
 490                                  unsigned long pnum_end,
 491                                  unsigned long map_count, int nodeid)
 492 {
 493         struct page **map_map = (struct page **)data;
 494         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
 495                                          map_count, nodeid);
 496 }
 497 #else
 498 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 499 {
 500         struct page *map;
 501         struct mem_section *ms = __nr_to_section(pnum);
 502         int nid = sparse_early_nid(ms);
 503
 504         map = sparse_mem_map_populate(pnum, nid, NULL);
 505         if (map)
 506                 return map;
 507
 508         pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
 509                __func__);
 510         ms->section_mem_map = 0;
 511         return NULL;
 512 }
 513 #endif
 514
 515 void __weak __meminit vmemmap_populate_print_last(void)
 516 {
 517 }
 518
 519 /**
 520  *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
 521  *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
 522  */
 523 static void __init alloc_usemap_and_memmap(void (*alloc_func)
 524                                         (void *, unsigned long, unsigned long,
 525                                         unsigned long, int), void *data)
 526 {
 527         unsigned long pnum;
 528         unsigned long map_count;
 529         int nodeid_begin = 0;
 530         unsigned long pnum_begin = 0;
 531
 532         for_each_present_section_nr(0, pnum) {
 533                 struct mem_section *ms;
 534
 535                 ms = __nr_to_section(pnum);
 536                 nodeid_begin = sparse_early_nid(ms);
 537                 pnum_begin = pnum;
 538                 break;
 539         }
 540         map_count = 1;
 541         for_each_present_section_nr(pnum_begin + 1, pnum) {
 542                 struct mem_section *ms;
 543                 int nodeid;
 544
 545                 ms = __nr_to_section(pnum);
 546                 nodeid = sparse_early_nid(ms);
 547                 if (nodeid == nodeid_begin) {
 548                         map_count++;
 549                         continue;
 550                 }
 551                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
 552                 alloc_func(data, pnum_begin, pnum,
 553                                                 map_count, nodeid_begin);
 554                 /* new start, update count etc*/
 555                 nodeid_begin = nodeid;
 556                 pnum_begin = pnum;
 557                 map_count = 1;
 558         }
 559         /* ok, last chunk */
 560         alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
 561                                                 map_count, nodeid_begin);
 562 }
 563
 564 /*
 565  * Allocate the accumulated non-linear sections, allocate a mem_map
 566  * for each and record the physical to section mapping.
 567  */
 568 void __init sparse_init(void)
 569 {
 570         unsigned long pnum;
 571         struct page *map;
 572         unsigned long *usemap;
 573         unsigned long **usemap_map;
 574         int size;
 575 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 576         int size2;
 577         struct page **map_map;
 578 #endif
 579
 580         /* see include/linux/mmzone.h 'struct mem_section' definition */
 581         BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
 582
 583         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 584         set_pageblock_order();
 585
 586         /*
 587          * map is using big page (aka 2M in x86 64 bit)
 588          * usemap is less one page (aka 24 bytes)
 589          * so alloc 2M (with 2M align) and 24 bytes in turn will
 590          * make next 2M slip to one more 2M later.
 591          * then in big system, the memory will have a lot of holes...
 592          * here try to allocate 2M pages continuously.
 593          *
 594          * powerpc need to call sparse_init_one_section right after each
 595          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
 596          */
 597         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
 598         usemap_map = memblock_virt_alloc(size, 0);
 599         if (!usemap_map)
 600                 panic("can not allocate usemap_map\n");
 601         alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
 602                                                         (void *)usemap_map);
 603
 604 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 605         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
 606         map_map = memblock_virt_alloc(size2, 0);
 607         if (!map_map)
 608                 panic("can not allocate map_map\n");
 609         alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
 610                                                         (void *)map_map);
 611 #endif
 612
 613         for_each_present_section_nr(0, pnum) {
 614                 usemap = usemap_map[pnum];
 615                 if (!usemap)
 616                         continue;
 617
 618 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 619                 map = map_map[pnum];
 620 #else
 621                 map = sparse_early_mem_map_alloc(pnum);
 622 #endif
 623                 if (!map)
 624                         continue;
 625
 626                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
 627                                                                 usemap);
 628         }
 629
 630         vmemmap_populate_print_last();
 631
 632 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 633         memblock_free_early(__pa(map_map), size2);
 634 #endif
 635         memblock_free_early(__pa(usemap_map), size);
 636 }
 637
 638 #ifdef CONFIG_MEMORY_HOTPLUG
 639
 640 /* Mark all memory sections within the pfn range as online */
 641 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 642 {
 643         unsigned long pfn;
 644
 645         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 646                 unsigned long section_nr = pfn_to_section_nr(pfn);
 647                 struct mem_section *ms;
 648
 649                 /* onlining code should never touch invalid ranges */
 650                 if (WARN_ON(!valid_section_nr(section_nr)))
 651                         continue;
 652
 653                 ms = __nr_to_section(section_nr);
 654                 ms->section_mem_map |= SECTION_IS_ONLINE;
 655         }
 656 }
 657
 658 #ifdef CONFIG_MEMORY_HOTREMOVE
 659 /* Mark all memory sections within the pfn range as online */
 660 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 661 {
 662         unsigned long pfn;
 663
 664         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 665                 unsigned long section_nr = pfn_to_section_nr(start_pfn);
 666                 struct mem_section *ms;
 667
 668                 /*
 669                  * TODO this needs some double checking. Offlining code makes
 670                  * sure to check pfn_valid but those checks might be just bogus
 671                  */
 672                 if (WARN_ON(!valid_section_nr(section_nr)))
 673                         continue;
 674
 675                 ms = __nr_to_section(section_nr);
 676                 ms->section_mem_map &= ~SECTION_IS_ONLINE;
 677         }
 678 }
 679 #endif
 680
 681 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 682 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 683                 struct vmem_altmap *altmap)
 684 {
 685         /* This will make the necessary allocations eventually. */
 686         return sparse_mem_map_populate(pnum, nid, altmap);
 687 }
 688 static void __kfree_section_memmap(struct page *memmap,
 689                 struct vmem_altmap *altmap)
 690 {
 691         unsigned long start = (unsigned long)memmap;
 692         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 693
 694         vmemmap_free(start, end, altmap);
 695 }
 696 #ifdef CONFIG_MEMORY_HOTREMOVE
 697 static void free_map_bootmem(struct page *memmap)
 698 {
 699         unsigned long start = (unsigned long)memmap;
 700         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 701
 702         vmemmap_free(start, end, NULL);
 703 }
 704 #endif /* CONFIG_MEMORY_HOTREMOVE */
 705 #else
 706 static struct page *__kmalloc_section_memmap(void)
 707 {
 708         struct page *page, *ret;
 709         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 710
 711         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 712         if (page)
 713                 goto got_map_page;
 714
 715         ret = vmalloc(memmap_size);
 716         if (ret)
 717                 goto got_map_ptr;
 718
 719         return NULL;
 720 got_map_page:
 721         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 722 got_map_ptr:
 723
 724         return ret;
 725 }
 726
 727 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 728                 struct vmem_altmap *altmap)
 729 {
 730         return __kmalloc_section_memmap();
 731 }
 732
 733 static void __kfree_section_memmap(struct page *memmap,
 734                 struct vmem_altmap *altmap)
 735 {
 736         if (is_vmalloc_addr(memmap))
 737                 vfree(memmap);
 738         else
 739                 free_pages((unsigned long)memmap,
 740                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
 741 }
 742
 743 #ifdef CONFIG_MEMORY_HOTREMOVE
 744 static void free_map_bootmem(struct page *memmap)
 745 {
 746         unsigned long maps_section_nr, removing_section_nr, i;
 747         unsigned long magic, nr_pages;
 748         struct page *page = virt_to_page(memmap);
 749
 750         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 751                 >> PAGE_SHIFT;
 752
 753         for (i = 0; i < nr_pages; i++, page++) {
 754                 magic = (unsigned long) page->freelist;
 755
 756                 BUG_ON(magic == NODE_INFO);
 757
 758                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 759                 removing_section_nr = page_private(page);
 760
 761                 /*
 762                  * When this function is called, the removing section is
 763                  * logical offlined state. This means all pages are isolated
 764                  * from page allocator. If removing section's memmap is placed
 765                  * on the same section, it must not be freed.
 766                  * If it is freed, page allocator may allocate it which will
 767                  * be removed physically soon.
 768                  */
 769                 if (maps_section_nr != removing_section_nr)
 770                         put_page_bootmem(page);
 771         }
 772 }
 773 #endif /* CONFIG_MEMORY_HOTREMOVE */
 774 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 775
 776 /*
 777  * returns the number of sections whose mem_maps were properly
 778  * set.  If this is <=0, then that means that the passed-in
 779  * map was not consumed and must be freed.
 780  */
 781 int __meminit sparse_add_one_section(struct pglist_data *pgdat,
 782                 unsigned long start_pfn, struct vmem_altmap *altmap)
 783 {
 784         unsigned long section_nr = pfn_to_section_nr(start_pfn);
 785         struct mem_section *ms;
 786         struct page *memmap;
 787         unsigned long *usemap;
 788         unsigned long flags;
 789         int ret;
 790
 791         /*
 792          * no locking for this, because it does its own
 793          * plus, it does a kmalloc
 794          */
 795         ret = sparse_index_init(section_nr, pgdat->node_id);
 796         if (ret < 0 && ret != -EEXIST)
 797                 return ret;
 798         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, altmap);
 799         if (!memmap)
 800                 return -ENOMEM;
 801         usemap = __kmalloc_section_usemap();
 802         if (!usemap) {
 803                 __kfree_section_memmap(memmap, altmap);
 804                 return -ENOMEM;
 805         }
 806
 807         pgdat_resize_lock(pgdat, &flags);
 808
 809         ms = __pfn_to_section(start_pfn);
 810         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 811                 ret = -EEXIST;
 812                 goto out;
 813         }
 814
 815         memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
 816
 817         section_mark_present(ms);
 818
 819         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
 820
 821 out:
 822         pgdat_resize_unlock(pgdat, &flags);
 823         if (ret <= 0) {
 824                 kfree(usemap);
 825                 __kfree_section_memmap(memmap, altmap);
 826         }
 827         return ret;
 828 }
 829
 830 #ifdef CONFIG_MEMORY_HOTREMOVE
 831 #ifdef CONFIG_MEMORY_FAILURE
 832 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 833 {
 834         int i;
 835
 836         if (!memmap)
 837                 return;
 838
 839         for (i = 0; i < nr_pages; i++) {
 840                 if (PageHWPoison(&memmap[i])) {
 841                         atomic_long_sub(1, &num_poisoned_pages);
 842                         ClearPageHWPoison(&memmap[i]);
 843                 }
 844         }
 845 }
 846 #else
 847 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 848 {
 849 }
 850 #endif
 851
 852 static void free_section_usemap(struct page *memmap, unsigned long *usemap,
 853                 struct vmem_altmap *altmap)
 854 {
 855         struct page *usemap_page;
 856
 857         if (!usemap)
 858                 return;
 859
 860         usemap_page = virt_to_page(usemap);
 861         /*
 862          * Check to see if allocation came from hot-plug-add
 863          */
 864         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 865                 kfree(usemap);
 866                 if (memmap)
 867                         __kfree_section_memmap(memmap, altmap);
 868                 return;
 869         }
 870
 871         /*
 872          * The usemap came from bootmem. This is packed with other usemaps
 873          * on the section which has pgdat at boot time. Just keep it as is now.
 874          */
 875
 876         if (memmap)
 877                 free_map_bootmem(memmap);
 878 }
 879
 880 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 881                 unsigned long map_offset, struct vmem_altmap *altmap)
 882 {
 883         struct page *memmap = NULL;
 884         unsigned long *usemap = NULL, flags;
 885         struct pglist_data *pgdat = zone->zone_pgdat;
 886
 887         pgdat_resize_lock(pgdat, &flags);
 888         if (ms->section_mem_map) {
 889                 usemap = ms->pageblock_flags;
 890                 memmap = sparse_decode_mem_map(ms->section_mem_map,
 891                                                 __section_nr(ms));
 892                 ms->section_mem_map = 0;
 893                 ms->pageblock_flags = NULL;
 894         }
 895         pgdat_resize_unlock(pgdat, &flags);
 896
 897         clear_hwpoisoned_pages(memmap + map_offset,
 898                         PAGES_PER_SECTION - map_offset);
 899         free_section_usemap(memmap, usemap, altmap);
 900 }
 901 #endif /* CONFIG_MEMORY_HOTREMOVE */
 902 #endif /* CONFIG_MEMORY_HOTPLUG */