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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/bootmem.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 | #include <asm/dma.h> | |
31 | #include <asm/pgalloc.h> | |
32 | #include <asm/pgtable.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_virt_alloc_try_nid_raw(size, align, goal, | |
46 | BOOTMEM_ALLOC_ACCESSIBLE, node); | |
47 | } | |
48 | ||
49 | static void *vmemmap_buf; | |
50 | static void *vmemmap_buf_end; | |
51 | ||
52 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) | |
53 | { | |
54 | /* If the main allocator is up use that, fallback to bootmem. */ | |
55 | if (slab_is_available()) { | |
56 | gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; | |
57 | int order = get_order(size); | |
58 | static bool warned; | |
59 | struct page *page; | |
60 | ||
61 | page = alloc_pages_node(node, gfp_mask, order); | |
62 | if (page) | |
63 | return page_address(page); | |
64 | ||
65 | if (!warned) { | |
66 | warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, | |
67 | "vmemmap alloc failure: order:%u", order); | |
68 | warned = true; | |
69 | } | |
70 | return NULL; | |
71 | } else | |
72 | return __earlyonly_bootmem_alloc(node, size, size, | |
73 | __pa(MAX_DMA_ADDRESS)); | |
74 | } | |
75 | ||
76 | /* need to make sure size is all the same during early stage */ | |
77 | static void * __meminit alloc_block_buf(unsigned long size, int node) | |
78 | { | |
79 | void *ptr; | |
80 | ||
81 | if (!vmemmap_buf) | |
82 | return vmemmap_alloc_block(size, node); | |
83 | ||
84 | /* take the from buf */ | |
85 | ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); | |
86 | if (ptr + size > vmemmap_buf_end) | |
87 | return vmemmap_alloc_block(size, node); | |
88 | ||
89 | vmemmap_buf = ptr + size; | |
90 | ||
91 | return ptr; | |
92 | } | |
93 | ||
94 | static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) | |
95 | { | |
96 | return altmap->base_pfn + altmap->reserve + altmap->alloc | |
97 | + altmap->align; | |
98 | } | |
99 | ||
100 | static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) | |
101 | { | |
102 | unsigned long allocated = altmap->alloc + altmap->align; | |
103 | ||
104 | if (altmap->free > allocated) | |
105 | return altmap->free - allocated; | |
106 | return 0; | |
107 | } | |
108 | ||
109 | /** | |
110 | * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation | |
111 | * @altmap - reserved page pool for the allocation | |
112 | * @nr_pfns - size (in pages) of the allocation | |
113 | * | |
114 | * Allocations are aligned to the size of the request | |
115 | */ | |
116 | static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap, | |
117 | unsigned long nr_pfns) | |
118 | { | |
119 | unsigned long pfn = vmem_altmap_next_pfn(altmap); | |
120 | unsigned long nr_align; | |
121 | ||
122 | nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); | |
123 | nr_align = ALIGN(pfn, nr_align) - pfn; | |
124 | ||
125 | if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) | |
126 | return ULONG_MAX; | |
127 | altmap->alloc += nr_pfns; | |
128 | altmap->align += nr_align; | |
129 | return pfn + nr_align; | |
130 | } | |
131 | ||
132 | static void * __meminit altmap_alloc_block_buf(unsigned long size, | |
133 | struct vmem_altmap *altmap) | |
134 | { | |
135 | unsigned long pfn, nr_pfns; | |
136 | void *ptr; | |
137 | ||
138 | if (size & ~PAGE_MASK) { | |
139 | pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", | |
140 | __func__, size); | |
141 | return NULL; | |
142 | } | |
143 | ||
144 | nr_pfns = size >> PAGE_SHIFT; | |
145 | pfn = vmem_altmap_alloc(altmap, nr_pfns); | |
146 | if (pfn < ULONG_MAX) | |
147 | ptr = __va(__pfn_to_phys(pfn)); | |
148 | else | |
149 | ptr = NULL; | |
150 | pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", | |
151 | __func__, pfn, altmap->alloc, altmap->align, nr_pfns); | |
152 | ||
153 | return ptr; | |
154 | } | |
155 | ||
156 | /* need to make sure size is all the same during early stage */ | |
157 | void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node, | |
158 | struct vmem_altmap *altmap) | |
159 | { | |
160 | if (altmap) | |
161 | return altmap_alloc_block_buf(size, altmap); | |
162 | return alloc_block_buf(size, node); | |
163 | } | |
164 | ||
165 | void __meminit vmemmap_verify(pte_t *pte, int node, | |
166 | unsigned long start, unsigned long end) | |
167 | { | |
168 | unsigned long pfn = pte_pfn(*pte); | |
169 | int actual_node = early_pfn_to_nid(pfn); | |
170 | ||
171 | if (node_distance(actual_node, node) > LOCAL_DISTANCE) | |
172 | pr_warn("[%lx-%lx] potential offnode page_structs\n", | |
173 | start, end - 1); | |
174 | } | |
175 | ||
176 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) | |
177 | { | |
178 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
179 | if (pte_none(*pte)) { | |
180 | pte_t entry; | |
181 | void *p = alloc_block_buf(PAGE_SIZE, node); | |
182 | if (!p) | |
183 | return NULL; | |
184 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); | |
185 | set_pte_at(&init_mm, addr, pte, entry); | |
186 | } | |
187 | return pte; | |
188 | } | |
189 | ||
190 | static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) | |
191 | { | |
192 | void *p = vmemmap_alloc_block(size, node); | |
193 | ||
194 | if (!p) | |
195 | return NULL; | |
196 | memset(p, 0, size); | |
197 | ||
198 | return p; | |
199 | } | |
200 | ||
201 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) | |
202 | { | |
203 | pmd_t *pmd = pmd_offset(pud, addr); | |
204 | if (pmd_none(*pmd)) { | |
205 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
206 | if (!p) | |
207 | return NULL; | |
208 | pmd_populate_kernel(&init_mm, pmd, p); | |
209 | } | |
210 | return pmd; | |
211 | } | |
212 | ||
213 | pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) | |
214 | { | |
215 | pud_t *pud = pud_offset(p4d, addr); | |
216 | if (pud_none(*pud)) { | |
217 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
218 | if (!p) | |
219 | return NULL; | |
220 | pud_populate(&init_mm, pud, p); | |
221 | } | |
222 | return pud; | |
223 | } | |
224 | ||
225 | p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) | |
226 | { | |
227 | p4d_t *p4d = p4d_offset(pgd, addr); | |
228 | if (p4d_none(*p4d)) { | |
229 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
230 | if (!p) | |
231 | return NULL; | |
232 | p4d_populate(&init_mm, p4d, p); | |
233 | } | |
234 | return p4d; | |
235 | } | |
236 | ||
237 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) | |
238 | { | |
239 | pgd_t *pgd = pgd_offset_k(addr); | |
240 | if (pgd_none(*pgd)) { | |
241 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
242 | if (!p) | |
243 | return NULL; | |
244 | pgd_populate(&init_mm, pgd, p); | |
245 | } | |
246 | return pgd; | |
247 | } | |
248 | ||
249 | int __meminit vmemmap_populate_basepages(unsigned long start, | |
250 | unsigned long end, int node) | |
251 | { | |
252 | unsigned long addr = start; | |
253 | pgd_t *pgd; | |
254 | p4d_t *p4d; | |
255 | pud_t *pud; | |
256 | pmd_t *pmd; | |
257 | pte_t *pte; | |
258 | ||
259 | for (; addr < end; addr += PAGE_SIZE) { | |
260 | pgd = vmemmap_pgd_populate(addr, node); | |
261 | if (!pgd) | |
262 | return -ENOMEM; | |
263 | p4d = vmemmap_p4d_populate(pgd, addr, node); | |
264 | if (!p4d) | |
265 | return -ENOMEM; | |
266 | pud = vmemmap_pud_populate(p4d, addr, node); | |
267 | if (!pud) | |
268 | return -ENOMEM; | |
269 | pmd = vmemmap_pmd_populate(pud, addr, node); | |
270 | if (!pmd) | |
271 | return -ENOMEM; | |
272 | pte = vmemmap_pte_populate(pmd, addr, node); | |
273 | if (!pte) | |
274 | return -ENOMEM; | |
275 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); | |
276 | } | |
277 | ||
278 | return 0; | |
279 | } | |
280 | ||
281 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) | |
282 | { | |
283 | unsigned long start; | |
284 | unsigned long end; | |
285 | struct page *map; | |
286 | ||
287 | map = pfn_to_page(pnum * PAGES_PER_SECTION); | |
288 | start = (unsigned long)map; | |
289 | end = (unsigned long)(map + PAGES_PER_SECTION); | |
290 | ||
291 | if (vmemmap_populate(start, end, nid)) | |
292 | return NULL; | |
293 | ||
294 | return map; | |
295 | } | |
296 | ||
297 | void __init sparse_mem_maps_populate_node(struct page **map_map, | |
298 | unsigned long pnum_begin, | |
299 | unsigned long pnum_end, | |
300 | unsigned long map_count, int nodeid) | |
301 | { | |
302 | unsigned long pnum; | |
303 | unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; | |
304 | void *vmemmap_buf_start; | |
305 | ||
306 | size = ALIGN(size, PMD_SIZE); | |
307 | vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, | |
308 | PMD_SIZE, __pa(MAX_DMA_ADDRESS)); | |
309 | ||
310 | if (vmemmap_buf_start) { | |
311 | vmemmap_buf = vmemmap_buf_start; | |
312 | vmemmap_buf_end = vmemmap_buf_start + size * map_count; | |
313 | } | |
314 | ||
315 | for (pnum = pnum_begin; pnum < pnum_end; pnum++) { | |
316 | struct mem_section *ms; | |
317 | ||
318 | if (!present_section_nr(pnum)) | |
319 | continue; | |
320 | ||
321 | map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); | |
322 | if (map_map[pnum]) | |
323 | continue; | |
324 | ms = __nr_to_section(pnum); | |
325 | pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", | |
326 | __func__); | |
327 | ms->section_mem_map = 0; | |
328 | } | |
329 | ||
330 | if (vmemmap_buf_start) { | |
331 | /* need to free left buf */ | |
332 | memblock_free_early(__pa(vmemmap_buf), | |
333 | vmemmap_buf_end - vmemmap_buf); | |
334 | vmemmap_buf = NULL; | |
335 | vmemmap_buf_end = NULL; | |
336 | } | |
337 | } |