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 #include <linux/swap.h> 15 #include <linux/swapops.h> 16 17 #include "internal.h" 18 #include <asm/dma.h> 19 #include <asm/pgalloc.h> 20 #include <asm/pgtable.h> 21 22 /* 23 * Permanent SPARSEMEM data: 24 * 25 * 1) mem_section - memory sections, mem_map's for valid memory 26 */ 27 #ifdef CONFIG_SPARSEMEM_EXTREME 28 struct mem_section **mem_section; 29 #else 30 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] 31 ____cacheline_internodealigned_in_smp; 32 #endif 33 EXPORT_SYMBOL(mem_section); 34 35 #ifdef NODE_NOT_IN_PAGE_FLAGS 36 /* 37 * If we did not store the node number in the page then we have to 38 * do a lookup in the section_to_node_table in order to find which 39 * node the page belongs to. 40 */ 41 #if MAX_NUMNODES <= 256 42 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; 43 #else 44 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; 45 #endif 46 47 int page_to_nid(const struct page *page) 48 { 49 return section_to_node_table[page_to_section(page)]; 50 } 51 EXPORT_SYMBOL(page_to_nid); 52 53 static void set_section_nid(unsigned long section_nr, int nid) 54 { 55 section_to_node_table[section_nr] = nid; 56 } 57 #else /* !NODE_NOT_IN_PAGE_FLAGS */ 58 static inline void set_section_nid(unsigned long section_nr, int nid) 59 { 60 } 61 #endif 62 63 #ifdef CONFIG_SPARSEMEM_EXTREME 64 static noinline struct mem_section __ref *sparse_index_alloc(int nid) 65 { 66 struct mem_section *section = NULL; 67 unsigned long array_size = SECTIONS_PER_ROOT * 68 sizeof(struct mem_section); 69 70 if (slab_is_available()) { 71 section = kzalloc_node(array_size, GFP_KERNEL, nid); 72 } else { 73 section = memblock_alloc_node(array_size, SMP_CACHE_BYTES, 74 nid); 75 if (!section) 76 panic("%s: Failed to allocate %lu bytes nid=%d\n", 77 __func__, array_size, nid); 78 } 79 80 return section; 81 } 82 83 static int __meminit sparse_index_init(unsigned long section_nr, int nid) 84 { 85 unsigned long root = SECTION_NR_TO_ROOT(section_nr); 86 struct mem_section *section; 87 88 /* 89 * An existing section is possible in the sub-section hotplug 90 * case. First hot-add instantiates, follow-on hot-add reuses 91 * the existing section. 92 * 93 * The mem_hotplug_lock resolves the apparent race below. 94 */ 95 if (mem_section[root]) 96 return 0; 97 98 section = sparse_index_alloc(nid); 99 if (!section) 100 return -ENOMEM; 101 102 mem_section[root] = section; 103 104 return 0; 105 } 106 #else /* !SPARSEMEM_EXTREME */ 107 static inline int sparse_index_init(unsigned long section_nr, int nid) 108 { 109 return 0; 110 } 111 #endif 112 113 #ifdef CONFIG_SPARSEMEM_EXTREME 114 unsigned long __section_nr(struct mem_section *ms) 115 { 116 unsigned long root_nr; 117 struct mem_section *root = NULL; 118 119 for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { 120 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); 121 if (!root) 122 continue; 123 124 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) 125 break; 126 } 127 128 VM_BUG_ON(!root); 129 130 return (root_nr * SECTIONS_PER_ROOT) + (ms - root); 131 } 132 #else 133 unsigned long __section_nr(struct mem_section *ms) 134 { 135 return (unsigned long)(ms - mem_section[0]); 136 } 137 #endif 138 139 /* 140 * During early boot, before section_mem_map is used for an actual 141 * mem_map, we use section_mem_map to store the section's NUMA 142 * node. This keeps us from having to use another data structure. The 143 * node information is cleared just before we store the real mem_map. 144 */ 145 static inline unsigned long sparse_encode_early_nid(int nid) 146 { 147 return (nid << SECTION_NID_SHIFT); 148 } 149 150 static inline int sparse_early_nid(struct mem_section *section) 151 { 152 return (section->section_mem_map >> SECTION_NID_SHIFT); 153 } 154 155 /* Validate the physical addressing limitations of the model */ 156 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn, 157 unsigned long *end_pfn) 158 { 159 unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT); 160 161 /* 162 * Sanity checks - do not allow an architecture to pass 163 * in larger pfns than the maximum scope of sparsemem: 164 */ 165 if (*start_pfn > max_sparsemem_pfn) { 166 mminit_dprintk(MMINIT_WARNING, "pfnvalidation", 167 "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n", 168 *start_pfn, *end_pfn, max_sparsemem_pfn); 169 WARN_ON_ONCE(1); 170 *start_pfn = max_sparsemem_pfn; 171 *end_pfn = max_sparsemem_pfn; 172 } else if (*end_pfn > max_sparsemem_pfn) { 173 mminit_dprintk(MMINIT_WARNING, "pfnvalidation", 174 "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n", 175 *start_pfn, *end_pfn, max_sparsemem_pfn); 176 WARN_ON_ONCE(1); 177 *end_pfn = max_sparsemem_pfn; 178 } 179 } 180 181 /* 182 * There are a number of times that we loop over NR_MEM_SECTIONS, 183 * looking for section_present() on each. But, when we have very 184 * large physical address spaces, NR_MEM_SECTIONS can also be 185 * very large which makes the loops quite long. 186 * 187 * Keeping track of this gives us an easy way to break out of 188 * those loops early. 189 */ 190 unsigned long __highest_present_section_nr; 191 static void section_mark_present(struct mem_section *ms) 192 { 193 unsigned long section_nr = __section_nr(ms); 194 195 if (section_nr > __highest_present_section_nr) 196 __highest_present_section_nr = section_nr; 197 198 ms->section_mem_map |= SECTION_MARKED_PRESENT; 199 } 200 201 #define for_each_present_section_nr(start, section_nr) \ 202 for (section_nr = next_present_section_nr(start-1); \ 203 ((section_nr != -1) && \ 204 (section_nr <= __highest_present_section_nr)); \ 205 section_nr = next_present_section_nr(section_nr)) 206 207 static inline unsigned long first_present_section_nr(void) 208 { 209 return next_present_section_nr(-1); 210 } 211 212 static void subsection_mask_set(unsigned long *map, unsigned long pfn, 213 unsigned long nr_pages) 214 { 215 int idx = subsection_map_index(pfn); 216 int end = subsection_map_index(pfn + nr_pages - 1); 217 218 bitmap_set(map, idx, end - idx + 1); 219 } 220 221 void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) 222 { 223 int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); 224 unsigned long nr, start_sec = pfn_to_section_nr(pfn); 225 226 if (!nr_pages) 227 return; 228 229 for (nr = start_sec; nr <= end_sec; nr++) { 230 struct mem_section *ms; 231 unsigned long pfns; 232 233 pfns = min(nr_pages, PAGES_PER_SECTION 234 - (pfn & ~PAGE_SECTION_MASK)); 235 ms = __nr_to_section(nr); 236 subsection_mask_set(ms->usage->subsection_map, pfn, pfns); 237 238 pr_debug("%s: sec: %lu pfns: %lu set(%d, %d)\n", __func__, nr, 239 pfns, subsection_map_index(pfn), 240 subsection_map_index(pfn + pfns - 1)); 241 242 pfn += pfns; 243 nr_pages -= pfns; 244 } 245 } 246 247 /* Record a memory area against a node. */ 248 void __init memory_present(int nid, unsigned long start, unsigned long end) 249 { 250 unsigned long pfn; 251 252 #ifdef CONFIG_SPARSEMEM_EXTREME 253 if (unlikely(!mem_section)) { 254 unsigned long size, align; 255 256 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS; 257 align = 1 << (INTERNODE_CACHE_SHIFT); 258 mem_section = memblock_alloc(size, align); 259 if (!mem_section) 260 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 261 __func__, size, align); 262 } 263 #endif 264 265 start &= PAGE_SECTION_MASK; 266 mminit_validate_memmodel_limits(&start, &end); 267 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { 268 unsigned long section = pfn_to_section_nr(pfn); 269 struct mem_section *ms; 270 271 sparse_index_init(section, nid); 272 set_section_nid(section, nid); 273 274 ms = __nr_to_section(section); 275 if (!ms->section_mem_map) { 276 ms->section_mem_map = sparse_encode_early_nid(nid) | 277 SECTION_IS_ONLINE; 278 section_mark_present(ms); 279 } 280 } 281 } 282 283 /* 284 * Mark all memblocks as present using memory_present(). This is a 285 * convienence function that is useful for a number of arches 286 * to mark all of the systems memory as present during initialization. 287 */ 288 void __init memblocks_present(void) 289 { 290 struct memblock_region *reg; 291 292 for_each_memblock(memory, reg) { 293 memory_present(memblock_get_region_node(reg), 294 memblock_region_memory_base_pfn(reg), 295 memblock_region_memory_end_pfn(reg)); 296 } 297 } 298 299 /* 300 * Subtle, we encode the real pfn into the mem_map such that 301 * the identity pfn - section_mem_map will return the actual 302 * physical page frame number. 303 */ 304 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) 305 { 306 unsigned long coded_mem_map = 307 (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); 308 BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT)); 309 BUG_ON(coded_mem_map & ~SECTION_MAP_MASK); 310 return coded_mem_map; 311 } 312 313 /* 314 * Decode mem_map from the coded memmap 315 */ 316 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) 317 { 318 /* mask off the extra low bits of information */ 319 coded_mem_map &= SECTION_MAP_MASK; 320 return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); 321 } 322 323 static void __meminit sparse_init_one_section(struct mem_section *ms, 324 unsigned long pnum, struct page *mem_map, 325 struct mem_section_usage *usage, unsigned long flags) 326 { 327 ms->section_mem_map &= ~SECTION_MAP_MASK; 328 ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) 329 | SECTION_HAS_MEM_MAP | flags; 330 ms->usage = usage; 331 } 332 333 static unsigned long usemap_size(void) 334 { 335 return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long); 336 } 337 338 size_t mem_section_usage_size(void) 339 { 340 return sizeof(struct mem_section_usage) + usemap_size(); 341 } 342 343 #ifdef CONFIG_MEMORY_HOTREMOVE 344 static struct mem_section_usage * __init 345 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, 346 unsigned long size) 347 { 348 struct mem_section_usage *usage; 349 unsigned long goal, limit; 350 int nid; 351 /* 352 * A page may contain usemaps for other sections preventing the 353 * page being freed and making a section unremovable while 354 * other sections referencing the usemap remain active. Similarly, 355 * a pgdat can prevent a section being removed. If section A 356 * contains a pgdat and section B contains the usemap, both 357 * sections become inter-dependent. This allocates usemaps 358 * from the same section as the pgdat where possible to avoid 359 * this problem. 360 */ 361 goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT); 362 limit = goal + (1UL << PA_SECTION_SHIFT); 363 nid = early_pfn_to_nid(goal >> PAGE_SHIFT); 364 again: 365 usage = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid); 366 if (!usage && limit) { 367 limit = 0; 368 goto again; 369 } 370 return usage; 371 } 372 373 static void __init check_usemap_section_nr(int nid, 374 struct mem_section_usage *usage) 375 { 376 unsigned long usemap_snr, pgdat_snr; 377 static unsigned long old_usemap_snr; 378 static unsigned long old_pgdat_snr; 379 struct pglist_data *pgdat = NODE_DATA(nid); 380 int usemap_nid; 381 382 /* First call */ 383 if (!old_usemap_snr) { 384 old_usemap_snr = NR_MEM_SECTIONS; 385 old_pgdat_snr = NR_MEM_SECTIONS; 386 } 387 388 usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT); 389 pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); 390 if (usemap_snr == pgdat_snr) 391 return; 392 393 if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr) 394 /* skip redundant message */ 395 return; 396 397 old_usemap_snr = usemap_snr; 398 old_pgdat_snr = pgdat_snr; 399 400 usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr)); 401 if (usemap_nid != nid) { 402 pr_info("node %d must be removed before remove section %ld\n", 403 nid, usemap_snr); 404 return; 405 } 406 /* 407 * There is a circular dependency. 408 * Some platforms allow un-removable section because they will just 409 * gather other removable sections for dynamic partitioning. 410 * Just notify un-removable section's number here. 411 */ 412 pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n", 413 usemap_snr, pgdat_snr, nid); 414 } 415 #else 416 static struct mem_section_usage * __init 417 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat, 418 unsigned long size) 419 { 420 return memblock_alloc_node(size, SMP_CACHE_BYTES, pgdat->node_id); 421 } 422 423 static void __init check_usemap_section_nr(int nid, 424 struct mem_section_usage *usage) 425 { 426 } 427 #endif /* CONFIG_MEMORY_HOTREMOVE */ 428 429 #ifdef CONFIG_SPARSEMEM_VMEMMAP 430 static unsigned long __init section_map_size(void) 431 { 432 return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE); 433 } 434 435 #else 436 static unsigned long __init section_map_size(void) 437 { 438 return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION); 439 } 440 441 struct page __init *__populate_section_memmap(unsigned long pfn, 442 unsigned long nr_pages, int nid, struct vmem_altmap *altmap) 443 { 444 unsigned long size = section_map_size(); 445 struct page *map = sparse_buffer_alloc(size); 446 phys_addr_t addr = __pa(MAX_DMA_ADDRESS); 447 448 if (map) 449 return map; 450 451 map = memblock_alloc_try_nid_raw(size, size, addr, 452 MEMBLOCK_ALLOC_ACCESSIBLE, nid); 453 if (!map) 454 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%pa\n", 455 __func__, size, PAGE_SIZE, nid, &addr); 456 457 return map; 458 } 459 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 460 461 static void *sparsemap_buf __meminitdata; 462 static void *sparsemap_buf_end __meminitdata; 463 464 static inline void __meminit sparse_buffer_free(unsigned long size) 465 { 466 WARN_ON(!sparsemap_buf || size == 0); 467 memblock_free_early(__pa(sparsemap_buf), size); 468 } 469 470 static void __init sparse_buffer_init(unsigned long size, int nid) 471 { 472 phys_addr_t addr = __pa(MAX_DMA_ADDRESS); 473 WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */ 474 /* 475 * Pre-allocated buffer is mainly used by __populate_section_memmap 476 * and we want it to be properly aligned to the section size - this is 477 * especially the case for VMEMMAP which maps memmap to PMDs 478 */ 479 sparsemap_buf = memblock_alloc_exact_nid_raw(size, section_map_size(), 480 addr, MEMBLOCK_ALLOC_ACCESSIBLE, nid); 481 sparsemap_buf_end = sparsemap_buf + size; 482 } 483 484 static void __init sparse_buffer_fini(void) 485 { 486 unsigned long size = sparsemap_buf_end - sparsemap_buf; 487 488 if (sparsemap_buf && size > 0) 489 sparse_buffer_free(size); 490 sparsemap_buf = NULL; 491 } 492 493 void * __meminit sparse_buffer_alloc(unsigned long size) 494 { 495 void *ptr = NULL; 496 497 if (sparsemap_buf) { 498 ptr = (void *) roundup((unsigned long)sparsemap_buf, size); 499 if (ptr + size > sparsemap_buf_end) 500 ptr = NULL; 501 else { 502 /* Free redundant aligned space */ 503 if ((unsigned long)(ptr - sparsemap_buf) > 0) 504 sparse_buffer_free((unsigned long)(ptr - sparsemap_buf)); 505 sparsemap_buf = ptr + size; 506 } 507 } 508 return ptr; 509 } 510 511 void __weak __meminit vmemmap_populate_print_last(void) 512 { 513 } 514 515 /* 516 * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end) 517 * And number of present sections in this node is map_count. 518 */ 519 static void __init sparse_init_nid(int nid, unsigned long pnum_begin, 520 unsigned long pnum_end, 521 unsigned long map_count) 522 { 523 struct mem_section_usage *usage; 524 unsigned long pnum; 525 struct page *map; 526 527 usage = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid), 528 mem_section_usage_size() * map_count); 529 if (!usage) { 530 pr_err("%s: node[%d] usemap allocation failed", __func__, nid); 531 goto failed; 532 } 533 sparse_buffer_init(map_count * section_map_size(), nid); 534 for_each_present_section_nr(pnum_begin, pnum) { 535 unsigned long pfn = section_nr_to_pfn(pnum); 536 537 if (pnum >= pnum_end) 538 break; 539 540 map = __populate_section_memmap(pfn, PAGES_PER_SECTION, 541 nid, NULL); 542 if (!map) { 543 pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.", 544 __func__, nid); 545 pnum_begin = pnum; 546 goto failed; 547 } 548 check_usemap_section_nr(nid, usage); 549 sparse_init_one_section(__nr_to_section(pnum), pnum, map, usage, 550 SECTION_IS_EARLY); 551 usage = (void *) usage + mem_section_usage_size(); 552 } 553 sparse_buffer_fini(); 554 return; 555 failed: 556 /* We failed to allocate, mark all the following pnums as not present */ 557 for_each_present_section_nr(pnum_begin, pnum) { 558 struct mem_section *ms; 559 560 if (pnum >= pnum_end) 561 break; 562 ms = __nr_to_section(pnum); 563 ms->section_mem_map = 0; 564 } 565 } 566 567 /* 568 * Allocate the accumulated non-linear sections, allocate a mem_map 569 * for each and record the physical to section mapping. 570 */ 571 void __init sparse_init(void) 572 { 573 unsigned long pnum_begin = first_present_section_nr(); 574 int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin)); 575 unsigned long pnum_end, map_count = 1; 576 577 /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */ 578 set_pageblock_order(); 579 580 for_each_present_section_nr(pnum_begin + 1, pnum_end) { 581 int nid = sparse_early_nid(__nr_to_section(pnum_end)); 582 583 if (nid == nid_begin) { 584 map_count++; 585 continue; 586 } 587 /* Init node with sections in range [pnum_begin, pnum_end) */ 588 sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count); 589 nid_begin = nid; 590 pnum_begin = pnum_end; 591 map_count = 1; 592 } 593 /* cover the last node */ 594 sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count); 595 vmemmap_populate_print_last(); 596 } 597 598 #ifdef CONFIG_MEMORY_HOTPLUG 599 600 /* Mark all memory sections within the pfn range as online */ 601 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn) 602 { 603 unsigned long pfn; 604 605 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 606 unsigned long section_nr = pfn_to_section_nr(pfn); 607 struct mem_section *ms; 608 609 /* onlining code should never touch invalid ranges */ 610 if (WARN_ON(!valid_section_nr(section_nr))) 611 continue; 612 613 ms = __nr_to_section(section_nr); 614 ms->section_mem_map |= SECTION_IS_ONLINE; 615 } 616 } 617 618 #ifdef CONFIG_MEMORY_HOTREMOVE 619 /* Mark all memory sections within the pfn range as offline */ 620 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn) 621 { 622 unsigned long pfn; 623 624 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 625 unsigned long section_nr = pfn_to_section_nr(pfn); 626 struct mem_section *ms; 627 628 /* 629 * TODO this needs some double checking. Offlining code makes 630 * sure to check pfn_valid but those checks might be just bogus 631 */ 632 if (WARN_ON(!valid_section_nr(section_nr))) 633 continue; 634 635 ms = __nr_to_section(section_nr); 636 ms->section_mem_map &= ~SECTION_IS_ONLINE; 637 } 638 } 639 #endif 640 641 #ifdef CONFIG_SPARSEMEM_VMEMMAP 642 static struct page * __meminit populate_section_memmap(unsigned long pfn, 643 unsigned long nr_pages, int nid, struct vmem_altmap *altmap) 644 { 645 return __populate_section_memmap(pfn, nr_pages, nid, altmap); 646 } 647 648 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, 649 struct vmem_altmap *altmap) 650 { 651 unsigned long start = (unsigned long) pfn_to_page(pfn); 652 unsigned long end = start + nr_pages * sizeof(struct page); 653 654 vmemmap_free(start, end, altmap); 655 } 656 static void free_map_bootmem(struct page *memmap) 657 { 658 unsigned long start = (unsigned long)memmap; 659 unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION); 660 661 vmemmap_free(start, end, NULL); 662 } 663 #else 664 struct page * __meminit populate_section_memmap(unsigned long pfn, 665 unsigned long nr_pages, int nid, struct vmem_altmap *altmap) 666 { 667 struct page *page, *ret; 668 unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION; 669 670 page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size)); 671 if (page) 672 goto got_map_page; 673 674 ret = vmalloc(memmap_size); 675 if (ret) 676 goto got_map_ptr; 677 678 return NULL; 679 got_map_page: 680 ret = (struct page *)pfn_to_kaddr(page_to_pfn(page)); 681 got_map_ptr: 682 683 return ret; 684 } 685 686 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, 687 struct vmem_altmap *altmap) 688 { 689 struct page *memmap = pfn_to_page(pfn); 690 691 if (is_vmalloc_addr(memmap)) 692 vfree(memmap); 693 else 694 free_pages((unsigned long)memmap, 695 get_order(sizeof(struct page) * PAGES_PER_SECTION)); 696 } 697 698 static void free_map_bootmem(struct page *memmap) 699 { 700 unsigned long maps_section_nr, removing_section_nr, i; 701 unsigned long magic, nr_pages; 702 struct page *page = virt_to_page(memmap); 703 704 nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page)) 705 >> PAGE_SHIFT; 706 707 for (i = 0; i < nr_pages; i++, page++) { 708 magic = (unsigned long) page->freelist; 709 710 BUG_ON(magic == NODE_INFO); 711 712 maps_section_nr = pfn_to_section_nr(page_to_pfn(page)); 713 removing_section_nr = page_private(page); 714 715 /* 716 * When this function is called, the removing section is 717 * logical offlined state. This means all pages are isolated 718 * from page allocator. If removing section's memmap is placed 719 * on the same section, it must not be freed. 720 * If it is freed, page allocator may allocate it which will 721 * be removed physically soon. 722 */ 723 if (maps_section_nr != removing_section_nr) 724 put_page_bootmem(page); 725 } 726 } 727 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 728 729 static void section_deactivate(unsigned long pfn, unsigned long nr_pages, 730 struct vmem_altmap *altmap) 731 { 732 DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; 733 DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; 734 struct mem_section *ms = __pfn_to_section(pfn); 735 bool section_is_early = early_section(ms); 736 struct page *memmap = NULL; 737 bool empty; 738 unsigned long *subsection_map = ms->usage 739 ? &ms->usage->subsection_map[0] : NULL; 740 741 subsection_mask_set(map, pfn, nr_pages); 742 if (subsection_map) 743 bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION); 744 745 if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), 746 "section already deactivated (%#lx + %ld)\n", 747 pfn, nr_pages)) 748 return; 749 750 /* 751 * There are 3 cases to handle across two configurations 752 * (SPARSEMEM_VMEMMAP={y,n}): 753 * 754 * 1/ deactivation of a partial hot-added section (only possible 755 * in the SPARSEMEM_VMEMMAP=y case). 756 * a/ section was present at memory init 757 * b/ section was hot-added post memory init 758 * 2/ deactivation of a complete hot-added section 759 * 3/ deactivation of a complete section from memory init 760 * 761 * For 1/, when subsection_map does not empty we will not be 762 * freeing the usage map, but still need to free the vmemmap 763 * range. 764 * 765 * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified 766 */ 767 bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); 768 empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION); 769 if (empty) { 770 unsigned long section_nr = pfn_to_section_nr(pfn); 771 772 /* 773 * When removing an early section, the usage map is kept (as the 774 * usage maps of other sections fall into the same page). It 775 * will be re-used when re-adding the section - which is then no 776 * longer an early section. If the usage map is PageReserved, it 777 * was allocated during boot. 778 */ 779 if (!PageReserved(virt_to_page(ms->usage))) { 780 kfree(ms->usage); 781 ms->usage = NULL; 782 } 783 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 784 /* 785 * Mark the section invalid so that valid_section() 786 * return false. This prevents code from dereferencing 787 * ms->usage array. 788 */ 789 ms->section_mem_map &= ~SECTION_HAS_MEM_MAP; 790 } 791 792 if (section_is_early && memmap) 793 free_map_bootmem(memmap); 794 else 795 depopulate_section_memmap(pfn, nr_pages, altmap); 796 797 if (empty) 798 ms->section_mem_map = (unsigned long)NULL; 799 } 800 801 static struct page * __meminit section_activate(int nid, unsigned long pfn, 802 unsigned long nr_pages, struct vmem_altmap *altmap) 803 { 804 DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; 805 struct mem_section *ms = __pfn_to_section(pfn); 806 struct mem_section_usage *usage = NULL; 807 unsigned long *subsection_map; 808 struct page *memmap; 809 int rc = 0; 810 811 subsection_mask_set(map, pfn, nr_pages); 812 813 if (!ms->usage) { 814 usage = kzalloc(mem_section_usage_size(), GFP_KERNEL); 815 if (!usage) 816 return ERR_PTR(-ENOMEM); 817 ms->usage = usage; 818 } 819 subsection_map = &ms->usage->subsection_map[0]; 820 821 if (bitmap_empty(map, SUBSECTIONS_PER_SECTION)) 822 rc = -EINVAL; 823 else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION)) 824 rc = -EEXIST; 825 else 826 bitmap_or(subsection_map, map, subsection_map, 827 SUBSECTIONS_PER_SECTION); 828 829 if (rc) { 830 if (usage) 831 ms->usage = NULL; 832 kfree(usage); 833 return ERR_PTR(rc); 834 } 835 836 /* 837 * The early init code does not consider partially populated 838 * initial sections, it simply assumes that memory will never be 839 * referenced. If we hot-add memory into such a section then we 840 * do not need to populate the memmap and can simply reuse what 841 * is already there. 842 */ 843 if (nr_pages < PAGES_PER_SECTION && early_section(ms)) 844 return pfn_to_page(pfn); 845 846 memmap = populate_section_memmap(pfn, nr_pages, nid, altmap); 847 if (!memmap) { 848 section_deactivate(pfn, nr_pages, altmap); 849 return ERR_PTR(-ENOMEM); 850 } 851 852 return memmap; 853 } 854 855 /** 856 * sparse_add_section - add a memory section, or populate an existing one 857 * @nid: The node to add section on 858 * @start_pfn: start pfn of the memory range 859 * @nr_pages: number of pfns to add in the section 860 * @altmap: device page map 861 * 862 * This is only intended for hotplug. 863 * 864 * Return: 865 * * 0 - On success. 866 * * -EEXIST - Section has been present. 867 * * -ENOMEM - Out of memory. 868 */ 869 int __meminit sparse_add_section(int nid, unsigned long start_pfn, 870 unsigned long nr_pages, struct vmem_altmap *altmap) 871 { 872 unsigned long section_nr = pfn_to_section_nr(start_pfn); 873 struct mem_section *ms; 874 struct page *memmap; 875 int ret; 876 877 ret = sparse_index_init(section_nr, nid); 878 if (ret < 0) 879 return ret; 880 881 memmap = section_activate(nid, start_pfn, nr_pages, altmap); 882 if (IS_ERR(memmap)) 883 return PTR_ERR(memmap); 884 885 /* 886 * Poison uninitialized struct pages in order to catch invalid flags 887 * combinations. 888 */ 889 page_init_poison(memmap, sizeof(struct page) * nr_pages); 890 891 ms = __nr_to_section(section_nr); 892 set_section_nid(section_nr, nid); 893 section_mark_present(ms); 894 895 /* Align memmap to section boundary in the subsection case */ 896 if (section_nr_to_pfn(section_nr) != start_pfn) 897 memmap = pfn_to_kaddr(section_nr_to_pfn(section_nr)); 898 sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0); 899 900 return 0; 901 } 902 903 #ifdef CONFIG_MEMORY_FAILURE 904 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) 905 { 906 int i; 907 908 /* 909 * A further optimization is to have per section refcounted 910 * num_poisoned_pages. But that would need more space per memmap, so 911 * for now just do a quick global check to speed up this routine in the 912 * absence of bad pages. 913 */ 914 if (atomic_long_read(&num_poisoned_pages) == 0) 915 return; 916 917 for (i = 0; i < nr_pages; i++) { 918 if (PageHWPoison(&memmap[i])) { 919 num_poisoned_pages_dec(); 920 ClearPageHWPoison(&memmap[i]); 921 } 922 } 923 } 924 #else 925 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) 926 { 927 } 928 #endif 929 930 void sparse_remove_section(struct mem_section *ms, unsigned long pfn, 931 unsigned long nr_pages, unsigned long map_offset, 932 struct vmem_altmap *altmap) 933 { 934 clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset, 935 nr_pages - map_offset); 936 section_deactivate(pfn, nr_pages, altmap); 937 } 938 #endif /* CONFIG_MEMORY_HOTPLUG */ 939