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1 | /* |
2 | * Virtual Memory Map support |
3 | * |
4 | * (C) 2007 sgi. Christoph Lameter. |
5 | * |
6 | * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn, |
7 | * virt_to_page, page_address() to be implemented as a base offset |
8 | * calculation without memory access. |
9 | * |
10 | * However, virtual mappings need a page table and TLBs. Many Linux |
11 | * architectures already map their physical space using 1-1 mappings |
12 | * via TLBs. For those arches the virtual memory map is essentially |
13 | * for free if we use the same page size as the 1-1 mappings. In that |
14 | * case the overhead consists of a few additional pages that are |
15 | * allocated to create a view of memory for vmemmap. |
16 | * |
17 | * The architecture is expected to provide a vmemmap_populate() function |
18 | * to instantiate the mapping. |
19 | */ |
20 | #include <linux/mm.h> |
21 | #include <linux/mmzone.h> |
22 | #include <linux/bootmem.h> |
23 | #include <linux/highmem.h> |
24 | #include <linux/module.h> |
25 | #include <linux/slab.h> |
26 | #include <linux/spinlock.h> |
27 | #include <linux/vmalloc.h> |
28 | #include <linux/sched.h> |
29 | #include <asm/dma.h> |
30 | #include <asm/pgalloc.h> |
31 | #include <asm/pgtable.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 * __init_refok __earlyonly_bootmem_alloc(int node, |
40 | unsigned long size, |
41 | unsigned long align, |
42 | unsigned long goal) |
43 | { |
44 | return __alloc_bootmem_node_high(NODE_DATA(node), size, align, goal); |
45 | } |
46 | |
47 | static void *vmemmap_buf; |
48 | static void *vmemmap_buf_end; |
49 | |
50 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) |
51 | { |
52 | /* If the main allocator is up use that, fallback to bootmem. */ |
53 | if (slab_is_available()) { |
54 | struct page *page; |
55 | |
56 | if (node_state(node, N_HIGH_MEMORY)) |
57 | page = alloc_pages_node(node, |
58 | GFP_KERNEL | __GFP_ZERO, get_order(size)); |
59 | else |
60 | page = alloc_pages(GFP_KERNEL | __GFP_ZERO, |
61 | get_order(size)); |
62 | if (page) |
63 | return page_address(page); |
64 | return NULL; |
65 | } else |
66 | return __earlyonly_bootmem_alloc(node, size, size, |
67 | __pa(MAX_DMA_ADDRESS)); |
68 | } |
69 | |
70 | /* need to make sure size is all the same during early stage */ |
71 | void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) |
72 | { |
73 | void *ptr; |
74 | |
75 | if (!vmemmap_buf) |
76 | return vmemmap_alloc_block(size, node); |
77 | |
78 | /* take the from buf */ |
79 | ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); |
80 | if (ptr + size > vmemmap_buf_end) |
81 | return vmemmap_alloc_block(size, node); |
82 | |
83 | vmemmap_buf = ptr + size; |
84 | |
85 | return ptr; |
86 | } |
87 | |
88 | void __meminit vmemmap_verify(pte_t *pte, int node, |
89 | unsigned long start, unsigned long end) |
90 | { |
91 | unsigned long pfn = pte_pfn(*pte); |
92 | int actual_node = early_pfn_to_nid(pfn); |
93 | |
94 | if (node_distance(actual_node, node) > LOCAL_DISTANCE) |
95 | printk(KERN_WARNING "[%lx-%lx] potential offnode " |
96 | "page_structs\n", start, end - 1); |
97 | } |
98 | |
99 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) |
100 | { |
101 | pte_t *pte = pte_offset_kernel(pmd, addr); |
102 | if (pte_none(*pte)) { |
103 | pte_t entry; |
104 | void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); |
105 | if (!p) |
106 | return NULL; |
107 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); |
108 | set_pte_at(&init_mm, addr, pte, entry); |
109 | } |
110 | return pte; |
111 | } |
112 | |
113 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) |
114 | { |
115 | pmd_t *pmd = pmd_offset(pud, addr); |
116 | if (pmd_none(*pmd)) { |
117 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
118 | if (!p) |
119 | return NULL; |
120 | pmd_populate_kernel(&init_mm, pmd, p); |
121 | } |
122 | return pmd; |
123 | } |
124 | |
125 | pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) |
126 | { |
127 | pud_t *pud = pud_offset(pgd, addr); |
128 | if (pud_none(*pud)) { |
129 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
130 | if (!p) |
131 | return NULL; |
132 | pud_populate(&init_mm, pud, p); |
133 | } |
134 | return pud; |
135 | } |
136 | |
137 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) |
138 | { |
139 | pgd_t *pgd = pgd_offset_k(addr); |
140 | if (pgd_none(*pgd)) { |
141 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
142 | if (!p) |
143 | return NULL; |
144 | pgd_populate(&init_mm, pgd, p); |
145 | } |
146 | return pgd; |
147 | } |
148 | |
149 | int __meminit vmemmap_populate_basepages(struct page *start_page, |
150 | unsigned long size, int node) |
151 | { |
152 | unsigned long addr = (unsigned long)start_page; |
153 | unsigned long end = (unsigned long)(start_page + size); |
154 | pgd_t *pgd; |
155 | pud_t *pud; |
156 | pmd_t *pmd; |
157 | pte_t *pte; |
158 | |
159 | for (; addr < end; addr += PAGE_SIZE) { |
160 | pgd = vmemmap_pgd_populate(addr, node); |
161 | if (!pgd) |
162 | return -ENOMEM; |
163 | pud = vmemmap_pud_populate(pgd, addr, node); |
164 | if (!pud) |
165 | return -ENOMEM; |
166 | pmd = vmemmap_pmd_populate(pud, addr, node); |
167 | if (!pmd) |
168 | return -ENOMEM; |
169 | pte = vmemmap_pte_populate(pmd, addr, node); |
170 | if (!pte) |
171 | return -ENOMEM; |
172 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); |
173 | } |
174 | |
175 | return 0; |
176 | } |
177 | |
178 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) |
179 | { |
180 | struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); |
181 | int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); |
182 | if (error) |
183 | return NULL; |
184 | |
185 | return map; |
186 | } |
187 | |
188 | void __init sparse_mem_maps_populate_node(struct page **map_map, |
189 | unsigned long pnum_begin, |
190 | unsigned long pnum_end, |
191 | unsigned long map_count, int nodeid) |
192 | { |
193 | unsigned long pnum; |
194 | unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; |
195 | void *vmemmap_buf_start; |
196 | |
197 | size = ALIGN(size, PMD_SIZE); |
198 | vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, |
199 | PMD_SIZE, __pa(MAX_DMA_ADDRESS)); |
200 | |
201 | if (vmemmap_buf_start) { |
202 | vmemmap_buf = vmemmap_buf_start; |
203 | vmemmap_buf_end = vmemmap_buf_start + size * map_count; |
204 | } |
205 | |
206 | for (pnum = pnum_begin; pnum < pnum_end; pnum++) { |
207 | struct mem_section *ms; |
208 | |
209 | if (!present_section_nr(pnum)) |
210 | continue; |
211 | |
212 | map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); |
213 | if (map_map[pnum]) |
214 | continue; |
215 | ms = __nr_to_section(pnum); |
216 | printk(KERN_ERR "%s: sparsemem memory map backing failed " |
217 | "some memory will not be available.\n", __func__); |
218 | ms->section_mem_map = 0; |
219 | } |
220 | |
221 | if (vmemmap_buf_start) { |
222 | /* need to free left buf */ |
223 | free_bootmem(__pa(vmemmap_buf), vmemmap_buf_end - vmemmap_buf); |
224 | vmemmap_buf = NULL; |
225 | vmemmap_buf_end = NULL; |
226 | } |
227 | } |
228 |
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