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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/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 | #include <asm/dma.h> | |
31 | #include <asm/pgalloc.h> | |
32 | ||
33 | /* | |
34 | * Allocate a block of memory to be used to back the virtual memory map | |
35 | * or to back the page tables that are used to create the mapping. | |
36 | * Uses the main allocators if they are available, else bootmem. | |
37 | */ | |
38 | ||
39 | static void * __ref __earlyonly_bootmem_alloc(int node, | |
40 | unsigned long size, | |
41 | unsigned long align, | |
42 | unsigned long goal) | |
43 | { | |
44 | return memblock_alloc_try_nid_raw(size, align, goal, | |
45 | MEMBLOCK_ALLOC_ACCESSIBLE, node); | |
46 | } | |
47 | ||
48 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) | |
49 | { | |
50 | /* If the main allocator is up use that, fallback to bootmem. */ | |
51 | if (slab_is_available()) { | |
52 | gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; | |
53 | int order = get_order(size); | |
54 | static bool warned; | |
55 | struct page *page; | |
56 | ||
57 | page = alloc_pages_node(node, gfp_mask, order); | |
58 | if (page) | |
59 | return page_address(page); | |
60 | ||
61 | if (!warned) { | |
62 | warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, | |
63 | "vmemmap alloc failure: order:%u", order); | |
64 | warned = true; | |
65 | } | |
66 | return NULL; | |
67 | } else | |
68 | return __earlyonly_bootmem_alloc(node, size, size, | |
69 | __pa(MAX_DMA_ADDRESS)); | |
70 | } | |
71 | ||
72 | static void * __meminit altmap_alloc_block_buf(unsigned long size, | |
73 | struct vmem_altmap *altmap); | |
74 | ||
75 | /* need to make sure size is all the same during early stage */ | |
76 | void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node, | |
77 | struct vmem_altmap *altmap) | |
78 | { | |
79 | void *ptr; | |
80 | ||
81 | if (altmap) | |
82 | return altmap_alloc_block_buf(size, altmap); | |
83 | ||
84 | ptr = sparse_buffer_alloc(size); | |
85 | if (!ptr) | |
86 | ptr = vmemmap_alloc_block(size, node); | |
87 | return ptr; | |
88 | } | |
89 | ||
90 | static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) | |
91 | { | |
92 | return altmap->base_pfn + altmap->reserve + altmap->alloc | |
93 | + altmap->align; | |
94 | } | |
95 | ||
96 | static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) | |
97 | { | |
98 | unsigned long allocated = altmap->alloc + altmap->align; | |
99 | ||
100 | if (altmap->free > allocated) | |
101 | return altmap->free - allocated; | |
102 | return 0; | |
103 | } | |
104 | ||
105 | static void * __meminit altmap_alloc_block_buf(unsigned long size, | |
106 | struct vmem_altmap *altmap) | |
107 | { | |
108 | unsigned long pfn, nr_pfns, nr_align; | |
109 | ||
110 | if (size & ~PAGE_MASK) { | |
111 | pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", | |
112 | __func__, size); | |
113 | return NULL; | |
114 | } | |
115 | ||
116 | pfn = vmem_altmap_next_pfn(altmap); | |
117 | nr_pfns = size >> PAGE_SHIFT; | |
118 | nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); | |
119 | nr_align = ALIGN(pfn, nr_align) - pfn; | |
120 | if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) | |
121 | return NULL; | |
122 | ||
123 | altmap->alloc += nr_pfns; | |
124 | altmap->align += nr_align; | |
125 | pfn += nr_align; | |
126 | ||
127 | pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", | |
128 | __func__, pfn, altmap->alloc, altmap->align, nr_pfns); | |
129 | return __va(__pfn_to_phys(pfn)); | |
130 | } | |
131 | ||
132 | void __meminit vmemmap_verify(pte_t *pte, int node, | |
133 | unsigned long start, unsigned long end) | |
134 | { | |
135 | unsigned long pfn = pte_pfn(*pte); | |
136 | int actual_node = early_pfn_to_nid(pfn); | |
137 | ||
138 | if (node_distance(actual_node, node) > LOCAL_DISTANCE) | |
139 | pr_warn("[%lx-%lx] potential offnode page_structs\n", | |
140 | start, end - 1); | |
141 | } | |
142 | ||
143 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node, | |
144 | struct vmem_altmap *altmap) | |
145 | { | |
146 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
147 | if (pte_none(*pte)) { | |
148 | pte_t entry; | |
149 | void *p; | |
150 | ||
151 | p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap); | |
152 | if (!p) | |
153 | return NULL; | |
154 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); | |
155 | set_pte_at(&init_mm, addr, pte, entry); | |
156 | } | |
157 | return pte; | |
158 | } | |
159 | ||
160 | static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) | |
161 | { | |
162 | void *p = vmemmap_alloc_block(size, node); | |
163 | ||
164 | if (!p) | |
165 | return NULL; | |
166 | memset(p, 0, size); | |
167 | ||
168 | return p; | |
169 | } | |
170 | ||
171 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) | |
172 | { | |
173 | pmd_t *pmd = pmd_offset(pud, addr); | |
174 | if (pmd_none(*pmd)) { | |
175 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
176 | if (!p) | |
177 | return NULL; | |
178 | pmd_populate_kernel(&init_mm, pmd, p); | |
179 | } | |
180 | return pmd; | |
181 | } | |
182 | ||
183 | pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) | |
184 | { | |
185 | pud_t *pud = pud_offset(p4d, addr); | |
186 | if (pud_none(*pud)) { | |
187 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
188 | if (!p) | |
189 | return NULL; | |
190 | pud_populate(&init_mm, pud, p); | |
191 | } | |
192 | return pud; | |
193 | } | |
194 | ||
195 | p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) | |
196 | { | |
197 | p4d_t *p4d = p4d_offset(pgd, addr); | |
198 | if (p4d_none(*p4d)) { | |
199 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
200 | if (!p) | |
201 | return NULL; | |
202 | p4d_populate(&init_mm, p4d, p); | |
203 | } | |
204 | return p4d; | |
205 | } | |
206 | ||
207 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) | |
208 | { | |
209 | pgd_t *pgd = pgd_offset_k(addr); | |
210 | if (pgd_none(*pgd)) { | |
211 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); | |
212 | if (!p) | |
213 | return NULL; | |
214 | pgd_populate(&init_mm, pgd, p); | |
215 | } | |
216 | return pgd; | |
217 | } | |
218 | ||
219 | int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end, | |
220 | int node, struct vmem_altmap *altmap) | |
221 | { | |
222 | unsigned long addr = start; | |
223 | pgd_t *pgd; | |
224 | p4d_t *p4d; | |
225 | pud_t *pud; | |
226 | pmd_t *pmd; | |
227 | pte_t *pte; | |
228 | ||
229 | for (; addr < end; addr += PAGE_SIZE) { | |
230 | pgd = vmemmap_pgd_populate(addr, node); | |
231 | if (!pgd) | |
232 | return -ENOMEM; | |
233 | p4d = vmemmap_p4d_populate(pgd, addr, node); | |
234 | if (!p4d) | |
235 | return -ENOMEM; | |
236 | pud = vmemmap_pud_populate(p4d, addr, node); | |
237 | if (!pud) | |
238 | return -ENOMEM; | |
239 | pmd = vmemmap_pmd_populate(pud, addr, node); | |
240 | if (!pmd) | |
241 | return -ENOMEM; | |
242 | pte = vmemmap_pte_populate(pmd, addr, node, altmap); | |
243 | if (!pte) | |
244 | return -ENOMEM; | |
245 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); | |
246 | } | |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
251 | struct page * __meminit __populate_section_memmap(unsigned long pfn, | |
252 | unsigned long nr_pages, int nid, struct vmem_altmap *altmap) | |
253 | { | |
254 | unsigned long start = (unsigned long) pfn_to_page(pfn); | |
255 | unsigned long end = start + nr_pages * sizeof(struct page); | |
256 | ||
257 | if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) || | |
258 | !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) | |
259 | return NULL; | |
260 | ||
261 | if (vmemmap_populate(start, end, nid, altmap)) | |
262 | return NULL; | |
263 | ||
264 | return pfn_to_page(pfn); | |
265 | } |