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/memblock.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_alloc_node(array_size, SMP_CACHE_BYTES,
  72                                               nid);
  73
  74         return section;
  75 }
  76
  77 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
  78 {
  79         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
  80         struct mem_section *section;
  81
  82         if (mem_section[root])
  83                 return -EEXIST;
  84
  85         section = sparse_index_alloc(nid);
  86         if (!section)
  87                 return -ENOMEM;
  88
  89         mem_section[root] = section;
  90
  91         return 0;
  92 }
  93 #else /* !SPARSEMEM_EXTREME */
  94 static inline int sparse_index_init(unsigned long section_nr, int nid)
  95 {
  96         return 0;
  97 }
  98 #endif
  99
 100 #ifdef CONFIG_SPARSEMEM_EXTREME
 101 int __section_nr(struct mem_section* ms)
 102 {
 103         unsigned long root_nr;
 104         struct mem_section *root = NULL;
 105
 106         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
 107                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 108                 if (!root)
 109                         continue;
 110
 111                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
 112                      break;
 113         }
 114
 115         VM_BUG_ON(!root);
 116
 117         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 118 }
 119 #else
 120 int __section_nr(struct mem_section* ms)
 121 {
 122         return (int)(ms - mem_section[0]);
 123 }
 124 #endif
 125
 126 /*
 127  * During early boot, before section_mem_map is used for an actual
 128  * mem_map, we use section_mem_map to store the section's NUMA
 129  * node.  This keeps us from having to use another data structure.  The
 130  * node information is cleared just before we store the real mem_map.
 131  */
 132 static inline unsigned long sparse_encode_early_nid(int nid)
 133 {
 134         return (nid << SECTION_NID_SHIFT);
 135 }
 136
 137 static inline int sparse_early_nid(struct mem_section *section)
 138 {
 139         return (section->section_mem_map >> SECTION_NID_SHIFT);
 140 }
 141
 142 /* Validate the physical addressing limitations of the model */
 143 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
 144                                                 unsigned long *end_pfn)
 145 {
 146         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
 147
 148         /*
 149          * Sanity checks - do not allow an architecture to pass
 150          * in larger pfns than the maximum scope of sparsemem:
 151          */
 152         if (*start_pfn > max_sparsemem_pfn) {
 153                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 154                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 155                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 156                 WARN_ON_ONCE(1);
 157                 *start_pfn = max_sparsemem_pfn;
 158                 *end_pfn = max_sparsemem_pfn;
 159         } else if (*end_pfn > max_sparsemem_pfn) {
 160                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 161                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 162                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 163                 WARN_ON_ONCE(1);
 164                 *end_pfn = max_sparsemem_pfn;
 165         }
 166 }
 167
 168 /*
 169  * There are a number of times that we loop over NR_MEM_SECTIONS,
 170  * looking for section_present() on each.  But, when we have very
 171  * large physical address spaces, NR_MEM_SECTIONS can also be
 172  * very large which makes the loops quite long.
 173  *
 174  * Keeping track of this gives us an easy way to break out of
 175  * those loops early.
 176  */
 177 int __highest_present_section_nr;
 178 static void section_mark_present(struct mem_section *ms)
 179 {
 180         int section_nr = __section_nr(ms);
 181
 182         if (section_nr > __highest_present_section_nr)
 183                 __highest_present_section_nr = section_nr;
 184
 185         ms->section_mem_map |= SECTION_MARKED_PRESENT;
 186 }
 187
 188 static inline int next_present_section_nr(int section_nr)
 189 {
 190         do {
 191                 section_nr++;
 192                 if (present_section_nr(section_nr))
 193                         return section_nr;
 194         } while ((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 <= __highest_present_section_nr));    \
 202              section_nr = next_present_section_nr(section_nr))
 203
 204 static inline unsigned long first_present_section_nr(void)
 205 {
 206         return next_present_section_nr(-1);
 207 }
 208
 209 /* Record a memory area against a node. */
 210 void __init memory_present(int nid, unsigned long start, unsigned long end)
 211 {
 212         unsigned long pfn;
 213
 214 #ifdef CONFIG_SPARSEMEM_EXTREME
 215         if (unlikely(!mem_section)) {
 216                 unsigned long size, align;
 217
 218                 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
 219                 align = 1 << (INTERNODE_CACHE_SHIFT);
 220                 mem_section = memblock_alloc(size, align);
 221         }
 222 #endif
 223
 224         start &= PAGE_SECTION_MASK;
 225         mminit_validate_memmodel_limits(&start, &end);
 226         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
 227                 unsigned long section = pfn_to_section_nr(pfn);
 228                 struct mem_section *ms;
 229
 230                 sparse_index_init(section, nid);
 231                 set_section_nid(section, nid);
 232
 233                 ms = __nr_to_section(section);
 234                 if (!ms->section_mem_map) {
 235                         ms->section_mem_map = sparse_encode_early_nid(nid) |
 236                                                         SECTION_IS_ONLINE;
 237                         section_mark_present(ms);
 238                 }
 239         }
 240 }
 241
 242 /*
 243  * Mark all memblocks as present using memory_present(). This is a
 244  * convienence function that is useful for a number of arches
 245  * to mark all of the systems memory as present during initialization.
 246  */
 247 void __init memblocks_present(void)
 248 {
 249         struct memblock_region *reg;
 250
 251         for_each_memblock(memory, reg) {
 252                 memory_present(memblock_get_region_node(reg),
 253                                memblock_region_memory_base_pfn(reg),
 254                                memblock_region_memory_end_pfn(reg));
 255         }
 256 }
 257
 258 /*
 259  * Subtle, we encode the real pfn into the mem_map such that
 260  * the identity pfn - section_mem_map will return the actual
 261  * physical page frame number.
 262  */
 263 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
 264 {
 265         unsigned long coded_mem_map =
 266                 (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
 267         BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT));
 268         BUG_ON(coded_mem_map & ~SECTION_MAP_MASK);
 269         return coded_mem_map;
 270 }
 271
 272 /*
 273  * Decode mem_map from the coded memmap
 274  */
 275 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
 276 {
 277         /* mask off the extra low bits of information */
 278         coded_mem_map &= SECTION_MAP_MASK;
 279         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 280 }
 281
 282 static void __meminit sparse_init_one_section(struct mem_section *ms,
 283                 unsigned long pnum, struct page *mem_map,
 284                 unsigned long *pageblock_bitmap)
 285 {
 286         ms->section_mem_map &= ~SECTION_MAP_MASK;
 287         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 288                                                         SECTION_HAS_MEM_MAP;
 289         ms->pageblock_flags = pageblock_bitmap;
 290 }
 291
 292 unsigned long usemap_size(void)
 293 {
 294         return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
 295 }
 296
 297 #ifdef CONFIG_MEMORY_HOTPLUG
 298 static unsigned long *__kmalloc_section_usemap(void)
 299 {
 300         return kmalloc(usemap_size(), GFP_KERNEL);
 301 }
 302 #endif /* CONFIG_MEMORY_HOTPLUG */
 303
 304 #ifdef CONFIG_MEMORY_HOTREMOVE
 305 static unsigned long * __init
 306 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 307                                          unsigned long size)
 308 {
 309         unsigned long goal, limit;
 310         unsigned long *p;
 311         int nid;
 312         /*
 313          * A page may contain usemaps for other sections preventing the
 314          * page being freed and making a section unremovable while
 315          * other sections referencing the usemap remain active. Similarly,
 316          * a pgdat can prevent a section being removed. If section A
 317          * contains a pgdat and section B contains the usemap, both
 318          * sections become inter-dependent. This allocates usemaps
 319          * from the same section as the pgdat where possible to avoid
 320          * this problem.
 321          */
 322         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
 323         limit = goal + (1UL << PA_SECTION_SHIFT);
 324         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 325 again:
 326         p = memblock_alloc_try_nid_nopanic(size,
 327                                                 SMP_CACHE_BYTES, goal, limit,
 328                                                 nid);
 329         if (!p && limit) {
 330                 limit = 0;
 331                 goto again;
 332         }
 333         return p;
 334 }
 335
 336 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 337 {
 338         unsigned long usemap_snr, pgdat_snr;
 339         static unsigned long old_usemap_snr;
 340         static unsigned long old_pgdat_snr;
 341         struct pglist_data *pgdat = NODE_DATA(nid);
 342         int usemap_nid;
 343
 344         /* First call */
 345         if (!old_usemap_snr) {
 346                 old_usemap_snr = NR_MEM_SECTIONS;
 347                 old_pgdat_snr = NR_MEM_SECTIONS;
 348         }
 349
 350         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
 351         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 352         if (usemap_snr == pgdat_snr)
 353                 return;
 354
 355         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
 356                 /* skip redundant message */
 357                 return;
 358
 359         old_usemap_snr = usemap_snr;
 360         old_pgdat_snr = pgdat_snr;
 361
 362         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
 363         if (usemap_nid != nid) {
 364                 pr_info("node %d must be removed before remove section %ld\n",
 365                         nid, usemap_snr);
 366                 return;
 367         }
 368         /*
 369          * There is a circular dependency.
 370          * Some platforms allow un-removable section because they will just
 371          * gather other removable sections for dynamic partitioning.
 372          * Just notify un-removable section's number here.
 373          */
 374         pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
 375                 usemap_snr, pgdat_snr, nid);
 376 }
 377 #else
 378 static unsigned long * __init
 379 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 380                                          unsigned long size)
 381 {
 382         return memblock_alloc_node_nopanic(size, pgdat->node_id);
 383 }
 384
 385 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 386 {
 387 }
 388 #endif /* CONFIG_MEMORY_HOTREMOVE */
 389
 390 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 391 static unsigned long __init section_map_size(void)
 392 {
 393         return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE);
 394 }
 395
 396 #else
 397 static unsigned long __init section_map_size(void)
 398 {
 399         return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 400 }
 401
 402 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
 403                 struct vmem_altmap *altmap)
 404 {
 405         unsigned long size = section_map_size();
 406         struct page *map = sparse_buffer_alloc(size);
 407
 408         if (map)
 409                 return map;
 410
 411         map = memblock_alloc_try_nid(size,
 412                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 413                                           MEMBLOCK_ALLOC_ACCESSIBLE, nid);
 414         return map;
 415 }
 416 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 417
 418 static void *sparsemap_buf __meminitdata;
 419 static void *sparsemap_buf_end __meminitdata;
 420
 421 static void __init sparse_buffer_init(unsigned long size, int nid)
 422 {
 423         WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */
 424         sparsemap_buf =
 425                 memblock_alloc_try_nid_raw(size, PAGE_SIZE,
 426                                                 __pa(MAX_DMA_ADDRESS),
 427                                                 MEMBLOCK_ALLOC_ACCESSIBLE, nid);
 428         sparsemap_buf_end = sparsemap_buf + size;
 429 }
 430
 431 static void __init sparse_buffer_fini(void)
 432 {
 433         unsigned long size = sparsemap_buf_end - sparsemap_buf;
 434
 435         if (sparsemap_buf && size > 0)
 436                 memblock_free_early(__pa(sparsemap_buf), size);
 437         sparsemap_buf = NULL;
 438 }
 439
 440 void * __meminit sparse_buffer_alloc(unsigned long size)
 441 {
 442         void *ptr = NULL;
 443
 444         if (sparsemap_buf) {
 445                 ptr = PTR_ALIGN(sparsemap_buf, size);
 446                 if (ptr + size > sparsemap_buf_end)
 447                         ptr = NULL;
 448                 else
 449                         sparsemap_buf = ptr + size;
 450         }
 451         return ptr;
 452 }
 453
 454 void __weak __meminit vmemmap_populate_print_last(void)
 455 {
 456 }
 457
 458 /*
 459  * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end)
 460  * And number of present sections in this node is map_count.
 461  */
 462 static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 463                                    unsigned long pnum_end,
 464                                    unsigned long map_count)
 465 {
 466         unsigned long pnum, usemap_longs, *usemap;
 467         struct page *map;
 468
 469         usemap_longs = BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS);
 470         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid),
 471                                                           usemap_size() *
 472                                                           map_count);
 473         if (!usemap) {
 474                 pr_err("%s: node[%d] usemap allocation failed", __func__, nid);
 475                 goto failed;
 476         }
 477         sparse_buffer_init(map_count * section_map_size(), nid);
 478         for_each_present_section_nr(pnum_begin, pnum) {
 479                 if (pnum >= pnum_end)
 480                         break;
 481
 482                 map = sparse_mem_map_populate(pnum, nid, NULL);
 483                 if (!map) {
 484                         pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
 485                                __func__, nid);
 486                         pnum_begin = pnum;
 487                         goto failed;
 488                 }
 489                 check_usemap_section_nr(nid, usemap);
 490                 sparse_init_one_section(__nr_to_section(pnum), pnum, map, usemap);
 491                 usemap += usemap_longs;
 492         }
 493         sparse_buffer_fini();
 494         return;
 495 failed:
 496         /* We failed to allocate, mark all the following pnums as not present */
 497         for_each_present_section_nr(pnum_begin, pnum) {
 498                 struct mem_section *ms;
 499
 500                 if (pnum >= pnum_end)
 501                         break;
 502                 ms = __nr_to_section(pnum);
 503                 ms->section_mem_map = 0;
 504         }
 505 }
 506
 507 /*
 508  * Allocate the accumulated non-linear sections, allocate a mem_map
 509  * for each and record the physical to section mapping.
 510  */
 511 void __init sparse_init(void)
 512 {
 513         unsigned long pnum_begin = first_present_section_nr();
 514         int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
 515         unsigned long pnum_end, map_count = 1;
 516
 517         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 518         set_pageblock_order();
 519
 520         for_each_present_section_nr(pnum_begin + 1, pnum_end) {
 521                 int nid = sparse_early_nid(__nr_to_section(pnum_end));
 522
 523                 if (nid == nid_begin) {
 524                         map_count++;
 525                         continue;
 526                 }
 527                 /* Init node with sections in range [pnum_begin, pnum_end) */
 528                 sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
 529                 nid_begin = nid;
 530                 pnum_begin = pnum_end;
 531                 map_count = 1;
 532         }
 533         /* cover the last node */
 534         sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
 535         vmemmap_populate_print_last();
 536 }
 537
 538 #ifdef CONFIG_MEMORY_HOTPLUG
 539
 540 /* Mark all memory sections within the pfn range as online */
 541 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 542 {
 543         unsigned long pfn;
 544
 545         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 546                 unsigned long section_nr = pfn_to_section_nr(pfn);
 547                 struct mem_section *ms;
 548
 549                 /* onlining code should never touch invalid ranges */
 550                 if (WARN_ON(!valid_section_nr(section_nr)))
 551                         continue;
 552
 553                 ms = __nr_to_section(section_nr);
 554                 ms->section_mem_map |= SECTION_IS_ONLINE;
 555         }
 556 }
 557
 558 #ifdef CONFIG_MEMORY_HOTREMOVE
 559 /* Mark all memory sections within the pfn range as online */
 560 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 561 {
 562         unsigned long pfn;
 563
 564         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 565                 unsigned long section_nr = pfn_to_section_nr(pfn);
 566                 struct mem_section *ms;
 567
 568                 /*
 569                  * TODO this needs some double checking. Offlining code makes
 570                  * sure to check pfn_valid but those checks might be just bogus
 571                  */
 572                 if (WARN_ON(!valid_section_nr(section_nr)))
 573                         continue;
 574
 575                 ms = __nr_to_section(section_nr);
 576                 ms->section_mem_map &= ~SECTION_IS_ONLINE;
 577         }
 578 }
 579 #endif
 580
 581 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 582 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 583                 struct vmem_altmap *altmap)
 584 {
 585         /* This will make the necessary allocations eventually. */
 586         return sparse_mem_map_populate(pnum, nid, altmap);
 587 }
 588 static void __kfree_section_memmap(struct page *memmap,
 589                 struct vmem_altmap *altmap)
 590 {
 591         unsigned long start = (unsigned long)memmap;
 592         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 593
 594         vmemmap_free(start, end, altmap);
 595 }
 596 #ifdef CONFIG_MEMORY_HOTREMOVE
 597 static void free_map_bootmem(struct page *memmap)
 598 {
 599         unsigned long start = (unsigned long)memmap;
 600         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 601
 602         vmemmap_free(start, end, NULL);
 603 }
 604 #endif /* CONFIG_MEMORY_HOTREMOVE */
 605 #else
 606 static struct page *__kmalloc_section_memmap(void)
 607 {
 608         struct page *page, *ret;
 609         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 610
 611         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 612         if (page)
 613                 goto got_map_page;
 614
 615         ret = vmalloc(memmap_size);
 616         if (ret)
 617                 goto got_map_ptr;
 618
 619         return NULL;
 620 got_map_page:
 621         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 622 got_map_ptr:
 623
 624         return ret;
 625 }
 626
 627 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 628                 struct vmem_altmap *altmap)
 629 {
 630         return __kmalloc_section_memmap();
 631 }
 632
 633 static void __kfree_section_memmap(struct page *memmap,
 634                 struct vmem_altmap *altmap)
 635 {
 636         if (is_vmalloc_addr(memmap))
 637                 vfree(memmap);
 638         else
 639                 free_pages((unsigned long)memmap,
 640                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
 641 }
 642
 643 #ifdef CONFIG_MEMORY_HOTREMOVE
 644 static void free_map_bootmem(struct page *memmap)
 645 {
 646         unsigned long maps_section_nr, removing_section_nr, i;
 647         unsigned long magic, nr_pages;
 648         struct page *page = virt_to_page(memmap);
 649
 650         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 651                 >> PAGE_SHIFT;
 652
 653         for (i = 0; i < nr_pages; i++, page++) {
 654                 magic = (unsigned long) page->freelist;
 655
 656                 BUG_ON(magic == NODE_INFO);
 657
 658                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 659                 removing_section_nr = page_private(page);
 660
 661                 /*
 662                  * When this function is called, the removing section is
 663                  * logical offlined state. This means all pages are isolated
 664                  * from page allocator. If removing section's memmap is placed
 665                  * on the same section, it must not be freed.
 666                  * If it is freed, page allocator may allocate it which will
 667                  * be removed physically soon.
 668                  */
 669                 if (maps_section_nr != removing_section_nr)
 670                         put_page_bootmem(page);
 671         }
 672 }
 673 #endif /* CONFIG_MEMORY_HOTREMOVE */
 674 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 675
 676 /*
 677  * returns the number of sections whose mem_maps were properly
 678  * set.  If this is <=0, then that means that the passed-in
 679  * map was not consumed and must be freed.
 680  */
 681 int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
 682                                      struct vmem_altmap *altmap)
 683 {
 684         unsigned long section_nr = pfn_to_section_nr(start_pfn);
 685         struct mem_section *ms;
 686         struct page *memmap;
 687         unsigned long *usemap;
 688         int ret;
 689
 690         /*
 691          * no locking for this, because it does its own
 692          * plus, it does a kmalloc
 693          */
 694         ret = sparse_index_init(section_nr, nid);
 695         if (ret < 0 && ret != -EEXIST)
 696                 return ret;
 697         ret = 0;
 698         memmap = kmalloc_section_memmap(section_nr, nid, altmap);
 699         if (!memmap)
 700                 return -ENOMEM;
 701         usemap = __kmalloc_section_usemap();
 702         if (!usemap) {
 703                 __kfree_section_memmap(memmap, altmap);
 704                 return -ENOMEM;
 705         }
 706
 707         ms = __pfn_to_section(start_pfn);
 708         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 709                 ret = -EEXIST;
 710                 goto out;
 711         }
 712
 713         /*
 714          * Poison uninitialized struct pages in order to catch invalid flags
 715          * combinations.
 716          */
 717         page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION);
 718
 719         section_mark_present(ms);
 720         sparse_init_one_section(ms, section_nr, memmap, usemap);
 721
 722 out:
 723         if (ret < 0) {
 724                 kfree(usemap);
 725                 __kfree_section_memmap(memmap, altmap);
 726         }
 727         return ret;
 728 }
 729
 730 #ifdef CONFIG_MEMORY_HOTREMOVE
 731 #ifdef CONFIG_MEMORY_FAILURE
 732 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 733 {
 734         int i;
 735
 736         if (!memmap)
 737                 return;
 738
 739         /*
 740          * A further optimization is to have per section refcounted
 741          * num_poisoned_pages.  But that would need more space per memmap, so
 742          * for now just do a quick global check to speed up this routine in the
 743          * absence of bad pages.
 744          */
 745         if (atomic_long_read(&num_poisoned_pages) == 0)
 746                 return;
 747
 748         for (i = 0; i < nr_pages; i++) {
 749                 if (PageHWPoison(&memmap[i])) {
 750                         atomic_long_sub(1, &num_poisoned_pages);
 751                         ClearPageHWPoison(&memmap[i]);
 752                 }
 753         }
 754 }
 755 #else
 756 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 757 {
 758 }
 759 #endif
 760
 761 static void free_section_usemap(struct page *memmap, unsigned long *usemap,
 762                 struct vmem_altmap *altmap)
 763 {
 764         struct page *usemap_page;
 765
 766         if (!usemap)
 767                 return;
 768
 769         usemap_page = virt_to_page(usemap);
 770         /*
 771          * Check to see if allocation came from hot-plug-add
 772          */
 773         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 774                 kfree(usemap);
 775                 if (memmap)
 776                         __kfree_section_memmap(memmap, altmap);
 777                 return;
 778         }
 779
 780         /*
 781          * The usemap came from bootmem. This is packed with other usemaps
 782          * on the section which has pgdat at boot time. Just keep it as is now.
 783          */
 784
 785         if (memmap)
 786                 free_map_bootmem(memmap);
 787 }
 788
 789 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 790                 unsigned long map_offset, struct vmem_altmap *altmap)
 791 {
 792         struct page *memmap = NULL;
 793         unsigned long *usemap = NULL;
 794
 795         if (ms->section_mem_map) {
 796                 usemap = ms->pageblock_flags;
 797                 memmap = sparse_decode_mem_map(ms->section_mem_map,
 798                                                 __section_nr(ms));
 799                 ms->section_mem_map = 0;
 800                 ms->pageblock_flags = NULL;
 801         }
 802
 803         clear_hwpoisoned_pages(memmap + map_offset,
 804                         PAGES_PER_SECTION - map_offset);
 805         free_section_usemap(memmap, usemap, altmap);
 806 }
 807 #endif /* CONFIG_MEMORY_HOTREMOVE */
 808 #endif /* CONFIG_MEMORY_HOTPLUG */