mmap: remove the IA64-specific vma expansion implementation
[linux-2.6-microblaze.git] / mm / sparse-vmemmap.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Virtual Memory Map support
4  *
5  * (C) 2007 sgi. Christoph Lameter.
6  *
7  * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
8  * virt_to_page, page_address() to be implemented as a base offset
9  * calculation without memory access.
10  *
11  * However, virtual mappings need a page table and TLBs. Many Linux
12  * architectures already map their physical space using 1-1 mappings
13  * via TLBs. For those arches the virtual memory map is essentially
14  * for free if we use the same page size as the 1-1 mappings. In that
15  * case the overhead consists of a few additional pages that are
16  * allocated to create a view of memory for vmemmap.
17  *
18  * The architecture is expected to provide a vmemmap_populate() function
19  * to instantiate the mapping.
20  */
21 #include <linux/mm.h>
22 #include <linux/mmzone.h>
23 #include <linux/memblock.h>
24 #include <linux/memremap.h>
25 #include <linux/highmem.h>
26 #include <linux/slab.h>
27 #include <linux/spinlock.h>
28 #include <linux/vmalloc.h>
29 #include <linux/sched.h>
30
31 #include <asm/dma.h>
32 #include <asm/pgalloc.h>
33
34 /*
35  * Allocate a block of memory to be used to back the virtual memory map
36  * or to back the page tables that are used to create the mapping.
37  * Uses the main allocators if they are available, else bootmem.
38  */
39
40 static void * __ref __earlyonly_bootmem_alloc(int node,
41                                 unsigned long size,
42                                 unsigned long align,
43                                 unsigned long goal)
44 {
45         return memblock_alloc_try_nid_raw(size, align, goal,
46                                                MEMBLOCK_ALLOC_ACCESSIBLE, node);
47 }
48
49 void * __meminit vmemmap_alloc_block(unsigned long size, int node)
50 {
51         /* If the main allocator is up use that, fallback to bootmem. */
52         if (slab_is_available()) {
53                 gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
54                 int order = get_order(size);
55                 static bool warned;
56                 struct page *page;
57
58                 page = alloc_pages_node(node, gfp_mask, order);
59                 if (page)
60                         return page_address(page);
61
62                 if (!warned) {
63                         warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,
64                                    "vmemmap alloc failure: order:%u", order);
65                         warned = true;
66                 }
67                 return NULL;
68         } else
69                 return __earlyonly_bootmem_alloc(node, size, size,
70                                 __pa(MAX_DMA_ADDRESS));
71 }
72
73 static void * __meminit altmap_alloc_block_buf(unsigned long size,
74                                                struct vmem_altmap *altmap);
75
76 /* need to make sure size is all the same during early stage */
77 void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node,
78                                          struct vmem_altmap *altmap)
79 {
80         void *ptr;
81
82         if (altmap)
83                 return altmap_alloc_block_buf(size, altmap);
84
85         ptr = sparse_buffer_alloc(size);
86         if (!ptr)
87                 ptr = vmemmap_alloc_block(size, node);
88         return ptr;
89 }
90
91 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
92 {
93         return altmap->base_pfn + altmap->reserve + altmap->alloc
94                 + altmap->align;
95 }
96
97 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
98 {
99         unsigned long allocated = altmap->alloc + altmap->align;
100
101         if (altmap->free > allocated)
102                 return altmap->free - allocated;
103         return 0;
104 }
105
106 static void * __meminit altmap_alloc_block_buf(unsigned long size,
107                                                struct vmem_altmap *altmap)
108 {
109         unsigned long pfn, nr_pfns, nr_align;
110
111         if (size & ~PAGE_MASK) {
112                 pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
113                                 __func__, size);
114                 return NULL;
115         }
116
117         pfn = vmem_altmap_next_pfn(altmap);
118         nr_pfns = size >> PAGE_SHIFT;
119         nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
120         nr_align = ALIGN(pfn, nr_align) - pfn;
121         if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
122                 return NULL;
123
124         altmap->alloc += nr_pfns;
125         altmap->align += nr_align;
126         pfn += nr_align;
127
128         pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
129                         __func__, pfn, altmap->alloc, altmap->align, nr_pfns);
130         return __va(__pfn_to_phys(pfn));
131 }
132
133 void __meminit vmemmap_verify(pte_t *pte, int node,
134                                 unsigned long start, unsigned long end)
135 {
136         unsigned long pfn = pte_pfn(ptep_get(pte));
137         int actual_node = early_pfn_to_nid(pfn);
138
139         if (node_distance(actual_node, node) > LOCAL_DISTANCE)
140                 pr_warn_once("[%lx-%lx] potential offnode page_structs\n",
141                         start, end - 1);
142 }
143
144 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
145                                        struct vmem_altmap *altmap,
146                                        struct page *reuse)
147 {
148         pte_t *pte = pte_offset_kernel(pmd, addr);
149         if (pte_none(ptep_get(pte))) {
150                 pte_t entry;
151                 void *p;
152
153                 if (!reuse) {
154                         p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap);
155                         if (!p)
156                                 return NULL;
157                 } else {
158                         /*
159                          * When a PTE/PMD entry is freed from the init_mm
160                          * there's a free_pages() call to this page allocated
161                          * above. Thus this get_page() is paired with the
162                          * put_page_testzero() on the freeing path.
163                          * This can only called by certain ZONE_DEVICE path,
164                          * and through vmemmap_populate_compound_pages() when
165                          * slab is available.
166                          */
167                         get_page(reuse);
168                         p = page_to_virt(reuse);
169                 }
170                 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
171                 set_pte_at(&init_mm, addr, pte, entry);
172         }
173         return pte;
174 }
175
176 static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
177 {
178         void *p = vmemmap_alloc_block(size, node);
179
180         if (!p)
181                 return NULL;
182         memset(p, 0, size);
183
184         return p;
185 }
186
187 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
188 {
189         pmd_t *pmd = pmd_offset(pud, addr);
190         if (pmd_none(*pmd)) {
191                 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
192                 if (!p)
193                         return NULL;
194                 pmd_populate_kernel(&init_mm, pmd, p);
195         }
196         return pmd;
197 }
198
199 void __weak __meminit pmd_init(void *addr)
200 {
201 }
202
203 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
204 {
205         pud_t *pud = pud_offset(p4d, addr);
206         if (pud_none(*pud)) {
207                 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
208                 if (!p)
209                         return NULL;
210                 pmd_init(p);
211                 pud_populate(&init_mm, pud, p);
212         }
213         return pud;
214 }
215
216 void __weak __meminit pud_init(void *addr)
217 {
218 }
219
220 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
221 {
222         p4d_t *p4d = p4d_offset(pgd, addr);
223         if (p4d_none(*p4d)) {
224                 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
225                 if (!p)
226                         return NULL;
227                 pud_init(p);
228                 p4d_populate(&init_mm, p4d, p);
229         }
230         return p4d;
231 }
232
233 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
234 {
235         pgd_t *pgd = pgd_offset_k(addr);
236         if (pgd_none(*pgd)) {
237                 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
238                 if (!p)
239                         return NULL;
240                 pgd_populate(&init_mm, pgd, p);
241         }
242         return pgd;
243 }
244
245 static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node,
246                                               struct vmem_altmap *altmap,
247                                               struct page *reuse)
248 {
249         pgd_t *pgd;
250         p4d_t *p4d;
251         pud_t *pud;
252         pmd_t *pmd;
253         pte_t *pte;
254
255         pgd = vmemmap_pgd_populate(addr, node);
256         if (!pgd)
257                 return NULL;
258         p4d = vmemmap_p4d_populate(pgd, addr, node);
259         if (!p4d)
260                 return NULL;
261         pud = vmemmap_pud_populate(p4d, addr, node);
262         if (!pud)
263                 return NULL;
264         pmd = vmemmap_pmd_populate(pud, addr, node);
265         if (!pmd)
266                 return NULL;
267         pte = vmemmap_pte_populate(pmd, addr, node, altmap, reuse);
268         if (!pte)
269                 return NULL;
270         vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
271
272         return pte;
273 }
274
275 static int __meminit vmemmap_populate_range(unsigned long start,
276                                             unsigned long end, int node,
277                                             struct vmem_altmap *altmap,
278                                             struct page *reuse)
279 {
280         unsigned long addr = start;
281         pte_t *pte;
282
283         for (; addr < end; addr += PAGE_SIZE) {
284                 pte = vmemmap_populate_address(addr, node, altmap, reuse);
285                 if (!pte)
286                         return -ENOMEM;
287         }
288
289         return 0;
290 }
291
292 int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
293                                          int node, struct vmem_altmap *altmap)
294 {
295         return vmemmap_populate_range(start, end, node, altmap, NULL);
296 }
297
298 void __weak __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
299                                       unsigned long addr, unsigned long next)
300 {
301 }
302
303 int __weak __meminit vmemmap_check_pmd(pmd_t *pmd, int node,
304                                        unsigned long addr, unsigned long next)
305 {
306         return 0;
307 }
308
309 int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end,
310                                          int node, struct vmem_altmap *altmap)
311 {
312         unsigned long addr;
313         unsigned long next;
314         pgd_t *pgd;
315         p4d_t *p4d;
316         pud_t *pud;
317         pmd_t *pmd;
318
319         for (addr = start; addr < end; addr = next) {
320                 next = pmd_addr_end(addr, end);
321
322                 pgd = vmemmap_pgd_populate(addr, node);
323                 if (!pgd)
324                         return -ENOMEM;
325
326                 p4d = vmemmap_p4d_populate(pgd, addr, node);
327                 if (!p4d)
328                         return -ENOMEM;
329
330                 pud = vmemmap_pud_populate(p4d, addr, node);
331                 if (!pud)
332                         return -ENOMEM;
333
334                 pmd = pmd_offset(pud, addr);
335                 if (pmd_none(READ_ONCE(*pmd))) {
336                         void *p;
337
338                         p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
339                         if (p) {
340                                 vmemmap_set_pmd(pmd, p, node, addr, next);
341                                 continue;
342                         } else if (altmap) {
343                                 /*
344                                  * No fallback: In any case we care about, the
345                                  * altmap should be reasonably sized and aligned
346                                  * such that vmemmap_alloc_block_buf() will always
347                                  * succeed. For consistency with the PTE case,
348                                  * return an error here as failure could indicate
349                                  * a configuration issue with the size of the altmap.
350                                  */
351                                 return -ENOMEM;
352                         }
353                 } else if (vmemmap_check_pmd(pmd, node, addr, next))
354                         continue;
355                 if (vmemmap_populate_basepages(addr, next, node, altmap))
356                         return -ENOMEM;
357         }
358         return 0;
359 }
360
361 #ifndef vmemmap_populate_compound_pages
362 /*
363  * For compound pages bigger than section size (e.g. x86 1G compound
364  * pages with 2M subsection size) fill the rest of sections as tail
365  * pages.
366  *
367  * Note that memremap_pages() resets @nr_range value and will increment
368  * it after each range successful onlining. Thus the value or @nr_range
369  * at section memmap populate corresponds to the in-progress range
370  * being onlined here.
371  */
372 static bool __meminit reuse_compound_section(unsigned long start_pfn,
373                                              struct dev_pagemap *pgmap)
374 {
375         unsigned long nr_pages = pgmap_vmemmap_nr(pgmap);
376         unsigned long offset = start_pfn -
377                 PHYS_PFN(pgmap->ranges[pgmap->nr_range].start);
378
379         return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION;
380 }
381
382 static pte_t * __meminit compound_section_tail_page(unsigned long addr)
383 {
384         pte_t *pte;
385
386         addr -= PAGE_SIZE;
387
388         /*
389          * Assuming sections are populated sequentially, the previous section's
390          * page data can be reused.
391          */
392         pte = pte_offset_kernel(pmd_off_k(addr), addr);
393         if (!pte)
394                 return NULL;
395
396         return pte;
397 }
398
399 static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn,
400                                                      unsigned long start,
401                                                      unsigned long end, int node,
402                                                      struct dev_pagemap *pgmap)
403 {
404         unsigned long size, addr;
405         pte_t *pte;
406         int rc;
407
408         if (reuse_compound_section(start_pfn, pgmap)) {
409                 pte = compound_section_tail_page(start);
410                 if (!pte)
411                         return -ENOMEM;
412
413                 /*
414                  * Reuse the page that was populated in the prior iteration
415                  * with just tail struct pages.
416                  */
417                 return vmemmap_populate_range(start, end, node, NULL,
418                                               pte_page(ptep_get(pte)));
419         }
420
421         size = min(end - start, pgmap_vmemmap_nr(pgmap) * sizeof(struct page));
422         for (addr = start; addr < end; addr += size) {
423                 unsigned long next, last = addr + size;
424
425                 /* Populate the head page vmemmap page */
426                 pte = vmemmap_populate_address(addr, node, NULL, NULL);
427                 if (!pte)
428                         return -ENOMEM;
429
430                 /* Populate the tail pages vmemmap page */
431                 next = addr + PAGE_SIZE;
432                 pte = vmemmap_populate_address(next, node, NULL, NULL);
433                 if (!pte)
434                         return -ENOMEM;
435
436                 /*
437                  * Reuse the previous page for the rest of tail pages
438                  * See layout diagram in Documentation/mm/vmemmap_dedup.rst
439                  */
440                 next += PAGE_SIZE;
441                 rc = vmemmap_populate_range(next, last, node, NULL,
442                                             pte_page(ptep_get(pte)));
443                 if (rc)
444                         return -ENOMEM;
445         }
446
447         return 0;
448 }
449
450 #endif
451
452 struct page * __meminit __populate_section_memmap(unsigned long pfn,
453                 unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
454                 struct dev_pagemap *pgmap)
455 {
456         unsigned long start = (unsigned long) pfn_to_page(pfn);
457         unsigned long end = start + nr_pages * sizeof(struct page);
458         int r;
459
460         if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) ||
461                 !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION)))
462                 return NULL;
463
464         if (vmemmap_can_optimize(altmap, pgmap))
465                 r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap);
466         else
467                 r = vmemmap_populate(start, end, nid, altmap);
468
469         if (r < 0)
470                 return NULL;
471
472         return pfn_to_page(pfn);
473 }