kconfig: qconf: remove unused voidPix, menuInvPix
[linux-2.6-microblaze.git] / 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 #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
21 /*
22  * Permanent SPARSEMEM data:
23  *
24  * 1) mem_section       - memory sections, mem_map's for valid memory
25  */
26 #ifdef CONFIG_SPARSEMEM_EXTREME
27 struct mem_section **mem_section;
28 #else
29 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
30         ____cacheline_internodealigned_in_smp;
31 #endif
32 EXPORT_SYMBOL(mem_section);
33
34 #ifdef NODE_NOT_IN_PAGE_FLAGS
35 /*
36  * If we did not store the node number in the page then we have to
37  * do a lookup in the section_to_node_table in order to find which
38  * node the page belongs to.
39  */
40 #if MAX_NUMNODES <= 256
41 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
42 #else
43 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
44 #endif
45
46 int page_to_nid(const struct page *page)
47 {
48         return section_to_node_table[page_to_section(page)];
49 }
50 EXPORT_SYMBOL(page_to_nid);
51
52 static void set_section_nid(unsigned long section_nr, int nid)
53 {
54         section_to_node_table[section_nr] = nid;
55 }
56 #else /* !NODE_NOT_IN_PAGE_FLAGS */
57 static inline void set_section_nid(unsigned long section_nr, int nid)
58 {
59 }
60 #endif
61
62 #ifdef CONFIG_SPARSEMEM_EXTREME
63 static noinline struct mem_section __ref *sparse_index_alloc(int nid)
64 {
65         struct mem_section *section = NULL;
66         unsigned long array_size = SECTIONS_PER_ROOT *
67                                    sizeof(struct mem_section);
68
69         if (slab_is_available()) {
70                 section = kzalloc_node(array_size, GFP_KERNEL, nid);
71         } else {
72                 section = memblock_alloc_node(array_size, SMP_CACHE_BYTES,
73                                               nid);
74                 if (!section)
75                         panic("%s: Failed to allocate %lu bytes nid=%d\n",
76                               __func__, array_size, nid);
77         }
78
79         return section;
80 }
81
82 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
83 {
84         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
85         struct mem_section *section;
86
87         /*
88          * An existing section is possible in the sub-section hotplug
89          * case. First hot-add instantiates, follow-on hot-add reuses
90          * the existing section.
91          *
92          * The mem_hotplug_lock resolves the apparent race below.
93          */
94         if (mem_section[root])
95                 return 0;
96
97         section = sparse_index_alloc(nid);
98         if (!section)
99                 return -ENOMEM;
100
101         mem_section[root] = section;
102
103         return 0;
104 }
105 #else /* !SPARSEMEM_EXTREME */
106 static inline int sparse_index_init(unsigned long section_nr, int nid)
107 {
108         return 0;
109 }
110 #endif
111
112 #ifdef CONFIG_SPARSEMEM_EXTREME
113 unsigned long __section_nr(struct mem_section *ms)
114 {
115         unsigned long root_nr;
116         struct mem_section *root = NULL;
117
118         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
119                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
120                 if (!root)
121                         continue;
122
123                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
124                      break;
125         }
126
127         VM_BUG_ON(!root);
128
129         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
130 }
131 #else
132 unsigned long __section_nr(struct mem_section *ms)
133 {
134         return (unsigned long)(ms - mem_section[0]);
135 }
136 #endif
137
138 /*
139  * During early boot, before section_mem_map is used for an actual
140  * mem_map, we use section_mem_map to store the section's NUMA
141  * node.  This keeps us from having to use another data structure.  The
142  * node information is cleared just before we store the real mem_map.
143  */
144 static inline unsigned long sparse_encode_early_nid(int nid)
145 {
146         return (nid << SECTION_NID_SHIFT);
147 }
148
149 static inline int sparse_early_nid(struct mem_section *section)
150 {
151         return (section->section_mem_map >> SECTION_NID_SHIFT);
152 }
153
154 /* Validate the physical addressing limitations of the model */
155 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
156                                                 unsigned long *end_pfn)
157 {
158         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
159
160         /*
161          * Sanity checks - do not allow an architecture to pass
162          * in larger pfns than the maximum scope of sparsemem:
163          */
164         if (*start_pfn > max_sparsemem_pfn) {
165                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
166                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
167                         *start_pfn, *end_pfn, max_sparsemem_pfn);
168                 WARN_ON_ONCE(1);
169                 *start_pfn = max_sparsemem_pfn;
170                 *end_pfn = max_sparsemem_pfn;
171         } else if (*end_pfn > max_sparsemem_pfn) {
172                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
173                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
174                         *start_pfn, *end_pfn, max_sparsemem_pfn);
175                 WARN_ON_ONCE(1);
176                 *end_pfn = max_sparsemem_pfn;
177         }
178 }
179
180 /*
181  * There are a number of times that we loop over NR_MEM_SECTIONS,
182  * looking for section_present() on each.  But, when we have very
183  * large physical address spaces, NR_MEM_SECTIONS can also be
184  * very large which makes the loops quite long.
185  *
186  * Keeping track of this gives us an easy way to break out of
187  * those loops early.
188  */
189 unsigned long __highest_present_section_nr;
190 static void section_mark_present(struct mem_section *ms)
191 {
192         unsigned long section_nr = __section_nr(ms);
193
194         if (section_nr > __highest_present_section_nr)
195                 __highest_present_section_nr = section_nr;
196
197         ms->section_mem_map |= SECTION_MARKED_PRESENT;
198 }
199
200 #define for_each_present_section_nr(start, section_nr)          \
201         for (section_nr = next_present_section_nr(start-1);     \
202              ((section_nr != -1) &&                             \
203               (section_nr <= __highest_present_section_nr));    \
204              section_nr = next_present_section_nr(section_nr))
205
206 static inline unsigned long first_present_section_nr(void)
207 {
208         return next_present_section_nr(-1);
209 }
210
211 #ifdef CONFIG_SPARSEMEM_VMEMMAP
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 #else
247 void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages)
248 {
249 }
250 #endif
251
252 /* Record a memory area against a node. */
253 void __init memory_present(int nid, unsigned long start, unsigned long end)
254 {
255         unsigned long pfn;
256
257 #ifdef CONFIG_SPARSEMEM_EXTREME
258         if (unlikely(!mem_section)) {
259                 unsigned long size, align;
260
261                 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
262                 align = 1 << (INTERNODE_CACHE_SHIFT);
263                 mem_section = memblock_alloc(size, align);
264                 if (!mem_section)
265                         panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
266                               __func__, size, align);
267         }
268 #endif
269
270         start &= PAGE_SECTION_MASK;
271         mminit_validate_memmodel_limits(&start, &end);
272         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
273                 unsigned long section = pfn_to_section_nr(pfn);
274                 struct mem_section *ms;
275
276                 sparse_index_init(section, nid);
277                 set_section_nid(section, nid);
278
279                 ms = __nr_to_section(section);
280                 if (!ms->section_mem_map) {
281                         ms->section_mem_map = sparse_encode_early_nid(nid) |
282                                                         SECTION_IS_ONLINE;
283                         section_mark_present(ms);
284                 }
285         }
286 }
287
288 /*
289  * Mark all memblocks as present using memory_present(). This is a
290  * convenience function that is useful for a number of arches
291  * to mark all of the systems memory as present during initialization.
292  */
293 void __init memblocks_present(void)
294 {
295         struct memblock_region *reg;
296
297         for_each_memblock(memory, reg) {
298                 memory_present(memblock_get_region_node(reg),
299                                memblock_region_memory_base_pfn(reg),
300                                memblock_region_memory_end_pfn(reg));
301         }
302 }
303
304 /*
305  * Subtle, we encode the real pfn into the mem_map such that
306  * the identity pfn - section_mem_map will return the actual
307  * physical page frame number.
308  */
309 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
310 {
311         unsigned long coded_mem_map =
312                 (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
313         BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT));
314         BUG_ON(coded_mem_map & ~SECTION_MAP_MASK);
315         return coded_mem_map;
316 }
317
318 /*
319  * Decode mem_map from the coded memmap
320  */
321 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
322 {
323         /* mask off the extra low bits of information */
324         coded_mem_map &= SECTION_MAP_MASK;
325         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
326 }
327
328 static void __meminit sparse_init_one_section(struct mem_section *ms,
329                 unsigned long pnum, struct page *mem_map,
330                 struct mem_section_usage *usage, unsigned long flags)
331 {
332         ms->section_mem_map &= ~SECTION_MAP_MASK;
333         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum)
334                 | SECTION_HAS_MEM_MAP | flags;
335         ms->usage = usage;
336 }
337
338 static unsigned long usemap_size(void)
339 {
340         return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
341 }
342
343 size_t mem_section_usage_size(void)
344 {
345         return sizeof(struct mem_section_usage) + usemap_size();
346 }
347
348 #ifdef CONFIG_MEMORY_HOTREMOVE
349 static struct mem_section_usage * __init
350 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
351                                          unsigned long size)
352 {
353         struct mem_section_usage *usage;
354         unsigned long goal, limit;
355         int nid;
356         /*
357          * A page may contain usemaps for other sections preventing the
358          * page being freed and making a section unremovable while
359          * other sections referencing the usemap remain active. Similarly,
360          * a pgdat can prevent a section being removed. If section A
361          * contains a pgdat and section B contains the usemap, both
362          * sections become inter-dependent. This allocates usemaps
363          * from the same section as the pgdat where possible to avoid
364          * this problem.
365          */
366         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
367         limit = goal + (1UL << PA_SECTION_SHIFT);
368         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
369 again:
370         usage = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid);
371         if (!usage && limit) {
372                 limit = 0;
373                 goto again;
374         }
375         return usage;
376 }
377
378 static void __init check_usemap_section_nr(int nid,
379                 struct mem_section_usage *usage)
380 {
381         unsigned long usemap_snr, pgdat_snr;
382         static unsigned long old_usemap_snr;
383         static unsigned long old_pgdat_snr;
384         struct pglist_data *pgdat = NODE_DATA(nid);
385         int usemap_nid;
386
387         /* First call */
388         if (!old_usemap_snr) {
389                 old_usemap_snr = NR_MEM_SECTIONS;
390                 old_pgdat_snr = NR_MEM_SECTIONS;
391         }
392
393         usemap_snr = pfn_to_section_nr(__pa(usage) >> PAGE_SHIFT);
394         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
395         if (usemap_snr == pgdat_snr)
396                 return;
397
398         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
399                 /* skip redundant message */
400                 return;
401
402         old_usemap_snr = usemap_snr;
403         old_pgdat_snr = pgdat_snr;
404
405         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
406         if (usemap_nid != nid) {
407                 pr_info("node %d must be removed before remove section %ld\n",
408                         nid, usemap_snr);
409                 return;
410         }
411         /*
412          * There is a circular dependency.
413          * Some platforms allow un-removable section because they will just
414          * gather other removable sections for dynamic partitioning.
415          * Just notify un-removable section's number here.
416          */
417         pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
418                 usemap_snr, pgdat_snr, nid);
419 }
420 #else
421 static struct mem_section_usage * __init
422 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
423                                          unsigned long size)
424 {
425         return memblock_alloc_node(size, SMP_CACHE_BYTES, pgdat->node_id);
426 }
427
428 static void __init check_usemap_section_nr(int nid,
429                 struct mem_section_usage *usage)
430 {
431 }
432 #endif /* CONFIG_MEMORY_HOTREMOVE */
433
434 #ifdef CONFIG_SPARSEMEM_VMEMMAP
435 static unsigned long __init section_map_size(void)
436 {
437         return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE);
438 }
439
440 #else
441 static unsigned long __init section_map_size(void)
442 {
443         return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
444 }
445
446 struct page __init *__populate_section_memmap(unsigned long pfn,
447                 unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
448 {
449         unsigned long size = section_map_size();
450         struct page *map = sparse_buffer_alloc(size);
451         phys_addr_t addr = __pa(MAX_DMA_ADDRESS);
452
453         if (map)
454                 return map;
455
456         map = memblock_alloc_try_nid_raw(size, size, addr,
457                                           MEMBLOCK_ALLOC_ACCESSIBLE, nid);
458         if (!map)
459                 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%pa\n",
460                       __func__, size, PAGE_SIZE, nid, &addr);
461
462         return map;
463 }
464 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
465
466 static void *sparsemap_buf __meminitdata;
467 static void *sparsemap_buf_end __meminitdata;
468
469 static inline void __meminit sparse_buffer_free(unsigned long size)
470 {
471         WARN_ON(!sparsemap_buf || size == 0);
472         memblock_free_early(__pa(sparsemap_buf), size);
473 }
474
475 static void __init sparse_buffer_init(unsigned long size, int nid)
476 {
477         phys_addr_t addr = __pa(MAX_DMA_ADDRESS);
478         WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */
479         /*
480          * Pre-allocated buffer is mainly used by __populate_section_memmap
481          * and we want it to be properly aligned to the section size - this is
482          * especially the case for VMEMMAP which maps memmap to PMDs
483          */
484         sparsemap_buf = memblock_alloc_exact_nid_raw(size, section_map_size(),
485                                         addr, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
486         sparsemap_buf_end = sparsemap_buf + size;
487 }
488
489 static void __init sparse_buffer_fini(void)
490 {
491         unsigned long size = sparsemap_buf_end - sparsemap_buf;
492
493         if (sparsemap_buf && size > 0)
494                 sparse_buffer_free(size);
495         sparsemap_buf = NULL;
496 }
497
498 void * __meminit sparse_buffer_alloc(unsigned long size)
499 {
500         void *ptr = NULL;
501
502         if (sparsemap_buf) {
503                 ptr = (void *) roundup((unsigned long)sparsemap_buf, size);
504                 if (ptr + size > sparsemap_buf_end)
505                         ptr = NULL;
506                 else {
507                         /* Free redundant aligned space */
508                         if ((unsigned long)(ptr - sparsemap_buf) > 0)
509                                 sparse_buffer_free((unsigned long)(ptr - sparsemap_buf));
510                         sparsemap_buf = ptr + size;
511                 }
512         }
513         return ptr;
514 }
515
516 void __weak __meminit vmemmap_populate_print_last(void)
517 {
518 }
519
520 /*
521  * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end)
522  * And number of present sections in this node is map_count.
523  */
524 static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
525                                    unsigned long pnum_end,
526                                    unsigned long map_count)
527 {
528         struct mem_section_usage *usage;
529         unsigned long pnum;
530         struct page *map;
531
532         usage = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid),
533                         mem_section_usage_size() * map_count);
534         if (!usage) {
535                 pr_err("%s: node[%d] usemap allocation failed", __func__, nid);
536                 goto failed;
537         }
538         sparse_buffer_init(map_count * section_map_size(), nid);
539         for_each_present_section_nr(pnum_begin, pnum) {
540                 unsigned long pfn = section_nr_to_pfn(pnum);
541
542                 if (pnum >= pnum_end)
543                         break;
544
545                 map = __populate_section_memmap(pfn, PAGES_PER_SECTION,
546                                 nid, NULL);
547                 if (!map) {
548                         pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
549                                __func__, nid);
550                         pnum_begin = pnum;
551                         goto failed;
552                 }
553                 check_usemap_section_nr(nid, usage);
554                 sparse_init_one_section(__nr_to_section(pnum), pnum, map, usage,
555                                 SECTION_IS_EARLY);
556                 usage = (void *) usage + mem_section_usage_size();
557         }
558         sparse_buffer_fini();
559         return;
560 failed:
561         /* We failed to allocate, mark all the following pnums as not present */
562         for_each_present_section_nr(pnum_begin, pnum) {
563                 struct mem_section *ms;
564
565                 if (pnum >= pnum_end)
566                         break;
567                 ms = __nr_to_section(pnum);
568                 ms->section_mem_map = 0;
569         }
570 }
571
572 /*
573  * Allocate the accumulated non-linear sections, allocate a mem_map
574  * for each and record the physical to section mapping.
575  */
576 void __init sparse_init(void)
577 {
578         unsigned long pnum_begin = first_present_section_nr();
579         int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
580         unsigned long pnum_end, map_count = 1;
581
582         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
583         set_pageblock_order();
584
585         for_each_present_section_nr(pnum_begin + 1, pnum_end) {
586                 int nid = sparse_early_nid(__nr_to_section(pnum_end));
587
588                 if (nid == nid_begin) {
589                         map_count++;
590                         continue;
591                 }
592                 /* Init node with sections in range [pnum_begin, pnum_end) */
593                 sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
594                 nid_begin = nid;
595                 pnum_begin = pnum_end;
596                 map_count = 1;
597         }
598         /* cover the last node */
599         sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
600         vmemmap_populate_print_last();
601 }
602
603 #ifdef CONFIG_MEMORY_HOTPLUG
604
605 /* Mark all memory sections within the pfn range as online */
606 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
607 {
608         unsigned long pfn;
609
610         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
611                 unsigned long section_nr = pfn_to_section_nr(pfn);
612                 struct mem_section *ms;
613
614                 /* onlining code should never touch invalid ranges */
615                 if (WARN_ON(!valid_section_nr(section_nr)))
616                         continue;
617
618                 ms = __nr_to_section(section_nr);
619                 ms->section_mem_map |= SECTION_IS_ONLINE;
620         }
621 }
622
623 #ifdef CONFIG_MEMORY_HOTREMOVE
624 /* Mark all memory sections within the pfn range as offline */
625 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
626 {
627         unsigned long pfn;
628
629         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
630                 unsigned long section_nr = pfn_to_section_nr(pfn);
631                 struct mem_section *ms;
632
633                 /*
634                  * TODO this needs some double checking. Offlining code makes
635                  * sure to check pfn_valid but those checks might be just bogus
636                  */
637                 if (WARN_ON(!valid_section_nr(section_nr)))
638                         continue;
639
640                 ms = __nr_to_section(section_nr);
641                 ms->section_mem_map &= ~SECTION_IS_ONLINE;
642         }
643 }
644 #endif
645
646 #ifdef CONFIG_SPARSEMEM_VMEMMAP
647 static struct page * __meminit populate_section_memmap(unsigned long pfn,
648                 unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
649 {
650         return __populate_section_memmap(pfn, nr_pages, nid, altmap);
651 }
652
653 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
654                 struct vmem_altmap *altmap)
655 {
656         unsigned long start = (unsigned long) pfn_to_page(pfn);
657         unsigned long end = start + nr_pages * sizeof(struct page);
658
659         vmemmap_free(start, end, altmap);
660 }
661 static void free_map_bootmem(struct page *memmap)
662 {
663         unsigned long start = (unsigned long)memmap;
664         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
665
666         vmemmap_free(start, end, NULL);
667 }
668
669 static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
670 {
671         DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
672         DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
673         struct mem_section *ms = __pfn_to_section(pfn);
674         unsigned long *subsection_map = ms->usage
675                 ? &ms->usage->subsection_map[0] : NULL;
676
677         subsection_mask_set(map, pfn, nr_pages);
678         if (subsection_map)
679                 bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION);
680
681         if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
682                                 "section already deactivated (%#lx + %ld)\n",
683                                 pfn, nr_pages))
684                 return -EINVAL;
685
686         bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
687         return 0;
688 }
689
690 static bool is_subsection_map_empty(struct mem_section *ms)
691 {
692         return bitmap_empty(&ms->usage->subsection_map[0],
693                             SUBSECTIONS_PER_SECTION);
694 }
695
696 static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
697 {
698         struct mem_section *ms = __pfn_to_section(pfn);
699         DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
700         unsigned long *subsection_map;
701         int rc = 0;
702
703         subsection_mask_set(map, pfn, nr_pages);
704
705         subsection_map = &ms->usage->subsection_map[0];
706
707         if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
708                 rc = -EINVAL;
709         else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION))
710                 rc = -EEXIST;
711         else
712                 bitmap_or(subsection_map, map, subsection_map,
713                                 SUBSECTIONS_PER_SECTION);
714
715         return rc;
716 }
717 #else
718 struct page * __meminit populate_section_memmap(unsigned long pfn,
719                 unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
720 {
721         return kvmalloc_node(array_size(sizeof(struct page),
722                                         PAGES_PER_SECTION), GFP_KERNEL, nid);
723 }
724
725 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
726                 struct vmem_altmap *altmap)
727 {
728         kvfree(pfn_to_page(pfn));
729 }
730
731 static void free_map_bootmem(struct page *memmap)
732 {
733         unsigned long maps_section_nr, removing_section_nr, i;
734         unsigned long magic, nr_pages;
735         struct page *page = virt_to_page(memmap);
736
737         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
738                 >> PAGE_SHIFT;
739
740         for (i = 0; i < nr_pages; i++, page++) {
741                 magic = (unsigned long) page->freelist;
742
743                 BUG_ON(magic == NODE_INFO);
744
745                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
746                 removing_section_nr = page_private(page);
747
748                 /*
749                  * When this function is called, the removing section is
750                  * logical offlined state. This means all pages are isolated
751                  * from page allocator. If removing section's memmap is placed
752                  * on the same section, it must not be freed.
753                  * If it is freed, page allocator may allocate it which will
754                  * be removed physically soon.
755                  */
756                 if (maps_section_nr != removing_section_nr)
757                         put_page_bootmem(page);
758         }
759 }
760
761 static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
762 {
763         return 0;
764 }
765
766 static bool is_subsection_map_empty(struct mem_section *ms)
767 {
768         return true;
769 }
770
771 static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
772 {
773         return 0;
774 }
775 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
776
777 /*
778  * To deactivate a memory region, there are 3 cases to handle across
779  * two configurations (SPARSEMEM_VMEMMAP={y,n}):
780  *
781  * 1. deactivation of a partial hot-added section (only possible in
782  *    the SPARSEMEM_VMEMMAP=y case).
783  *      a) section was present at memory init.
784  *      b) section was hot-added post memory init.
785  * 2. deactivation of a complete hot-added section.
786  * 3. deactivation of a complete section from memory init.
787  *
788  * For 1, when subsection_map does not empty we will not be freeing the
789  * usage map, but still need to free the vmemmap range.
790  *
791  * For 2 and 3, the SPARSEMEM_VMEMMAP={y,n} cases are unified
792  */
793 static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
794                 struct vmem_altmap *altmap)
795 {
796         struct mem_section *ms = __pfn_to_section(pfn);
797         bool section_is_early = early_section(ms);
798         struct page *memmap = NULL;
799         bool empty;
800
801         if (clear_subsection_map(pfn, nr_pages))
802                 return;
803
804         empty = is_subsection_map_empty(ms);
805         if (empty) {
806                 unsigned long section_nr = pfn_to_section_nr(pfn);
807
808                 /*
809                  * When removing an early section, the usage map is kept (as the
810                  * usage maps of other sections fall into the same page). It
811                  * will be re-used when re-adding the section - which is then no
812                  * longer an early section. If the usage map is PageReserved, it
813                  * was allocated during boot.
814                  */
815                 if (!PageReserved(virt_to_page(ms->usage))) {
816                         kfree(ms->usage);
817                         ms->usage = NULL;
818                 }
819                 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
820                 /*
821                  * Mark the section invalid so that valid_section()
822                  * return false. This prevents code from dereferencing
823                  * ms->usage array.
824                  */
825                 ms->section_mem_map &= ~SECTION_HAS_MEM_MAP;
826         }
827
828         if (section_is_early && memmap)
829                 free_map_bootmem(memmap);
830         else
831                 depopulate_section_memmap(pfn, nr_pages, altmap);
832
833         if (empty)
834                 ms->section_mem_map = (unsigned long)NULL;
835 }
836
837 static struct page * __meminit section_activate(int nid, unsigned long pfn,
838                 unsigned long nr_pages, struct vmem_altmap *altmap)
839 {
840         struct mem_section *ms = __pfn_to_section(pfn);
841         struct mem_section_usage *usage = NULL;
842         struct page *memmap;
843         int rc = 0;
844
845         if (!ms->usage) {
846                 usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
847                 if (!usage)
848                         return ERR_PTR(-ENOMEM);
849                 ms->usage = usage;
850         }
851
852         rc = fill_subsection_map(pfn, nr_pages);
853         if (rc) {
854                 if (usage)
855                         ms->usage = NULL;
856                 kfree(usage);
857                 return ERR_PTR(rc);
858         }
859
860         /*
861          * The early init code does not consider partially populated
862          * initial sections, it simply assumes that memory will never be
863          * referenced.  If we hot-add memory into such a section then we
864          * do not need to populate the memmap and can simply reuse what
865          * is already there.
866          */
867         if (nr_pages < PAGES_PER_SECTION && early_section(ms))
868                 return pfn_to_page(pfn);
869
870         memmap = populate_section_memmap(pfn, nr_pages, nid, altmap);
871         if (!memmap) {
872                 section_deactivate(pfn, nr_pages, altmap);
873                 return ERR_PTR(-ENOMEM);
874         }
875
876         return memmap;
877 }
878
879 /**
880  * sparse_add_section - add a memory section, or populate an existing one
881  * @nid: The node to add section on
882  * @start_pfn: start pfn of the memory range
883  * @nr_pages: number of pfns to add in the section
884  * @altmap: device page map
885  *
886  * This is only intended for hotplug.
887  *
888  * Note that only VMEMMAP supports sub-section aligned hotplug,
889  * the proper alignment and size are gated by check_pfn_span().
890  *
891  *
892  * Return:
893  * * 0          - On success.
894  * * -EEXIST    - Section has been present.
895  * * -ENOMEM    - Out of memory.
896  */
897 int __meminit sparse_add_section(int nid, unsigned long start_pfn,
898                 unsigned long nr_pages, struct vmem_altmap *altmap)
899 {
900         unsigned long section_nr = pfn_to_section_nr(start_pfn);
901         struct mem_section *ms;
902         struct page *memmap;
903         int ret;
904
905         ret = sparse_index_init(section_nr, nid);
906         if (ret < 0)
907                 return ret;
908
909         memmap = section_activate(nid, start_pfn, nr_pages, altmap);
910         if (IS_ERR(memmap))
911                 return PTR_ERR(memmap);
912
913         /*
914          * Poison uninitialized struct pages in order to catch invalid flags
915          * combinations.
916          */
917         page_init_poison(memmap, sizeof(struct page) * nr_pages);
918
919         ms = __nr_to_section(section_nr);
920         set_section_nid(section_nr, nid);
921         section_mark_present(ms);
922
923         /* Align memmap to section boundary in the subsection case */
924         if (section_nr_to_pfn(section_nr) != start_pfn)
925                 memmap = pfn_to_page(section_nr_to_pfn(section_nr));
926         sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0);
927
928         return 0;
929 }
930
931 #ifdef CONFIG_MEMORY_FAILURE
932 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
933 {
934         int i;
935
936         /*
937          * A further optimization is to have per section refcounted
938          * num_poisoned_pages.  But that would need more space per memmap, so
939          * for now just do a quick global check to speed up this routine in the
940          * absence of bad pages.
941          */
942         if (atomic_long_read(&num_poisoned_pages) == 0)
943                 return;
944
945         for (i = 0; i < nr_pages; i++) {
946                 if (PageHWPoison(&memmap[i])) {
947                         num_poisoned_pages_dec();
948                         ClearPageHWPoison(&memmap[i]);
949                 }
950         }
951 }
952 #else
953 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
954 {
955 }
956 #endif
957
958 void sparse_remove_section(struct mem_section *ms, unsigned long pfn,
959                 unsigned long nr_pages, unsigned long map_offset,
960                 struct vmem_altmap *altmap)
961 {
962         clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset,
963                         nr_pages - map_offset);
964         section_deactivate(pfn, nr_pages, altmap);
965 }
966 #endif /* CONFIG_MEMORY_HOTPLUG */