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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/slab.h> |
25 | #include <linux/spinlock.h> |
26 | #include <linux/vmalloc.h> |
27 | #include <linux/sched.h> |
28 | #include <asm/dma.h> |
29 | #include <asm/pgalloc.h> |
30 | #include <asm/pgtable.h> |
31 | |
32 | /* |
33 | * Allocate a block of memory to be used to back the virtual memory map |
34 | * or to back the page tables that are used to create the mapping. |
35 | * Uses the main allocators if they are available, else bootmem. |
36 | */ |
37 | |
38 | static void * __init_refok __earlyonly_bootmem_alloc(int node, |
39 | unsigned long size, |
40 | unsigned long align, |
41 | unsigned long goal) |
42 | { |
43 | return __alloc_bootmem_node_high(NODE_DATA(node), size, align, goal); |
44 | } |
45 | |
46 | static void *vmemmap_buf; |
47 | static void *vmemmap_buf_end; |
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 | struct page *page; |
54 | |
55 | if (node_state(node, N_HIGH_MEMORY)) |
56 | page = alloc_pages_node(node, |
57 | GFP_KERNEL | __GFP_ZERO, get_order(size)); |
58 | else |
59 | page = alloc_pages(GFP_KERNEL | __GFP_ZERO, |
60 | get_order(size)); |
61 | if (page) |
62 | return page_address(page); |
63 | return NULL; |
64 | } else |
65 | return __earlyonly_bootmem_alloc(node, size, size, |
66 | __pa(MAX_DMA_ADDRESS)); |
67 | } |
68 | |
69 | /* need to make sure size is all the same during early stage */ |
70 | void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) |
71 | { |
72 | void *ptr; |
73 | |
74 | if (!vmemmap_buf) |
75 | return vmemmap_alloc_block(size, node); |
76 | |
77 | /* take the from buf */ |
78 | ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); |
79 | if (ptr + size > vmemmap_buf_end) |
80 | return vmemmap_alloc_block(size, node); |
81 | |
82 | vmemmap_buf = ptr + size; |
83 | |
84 | return ptr; |
85 | } |
86 | |
87 | void __meminit vmemmap_verify(pte_t *pte, int node, |
88 | unsigned long start, unsigned long end) |
89 | { |
90 | unsigned long pfn = pte_pfn(*pte); |
91 | int actual_node = early_pfn_to_nid(pfn); |
92 | |
93 | if (node_distance(actual_node, node) > LOCAL_DISTANCE) |
94 | printk(KERN_WARNING "[%lx-%lx] potential offnode " |
95 | "page_structs\n", start, end - 1); |
96 | } |
97 | |
98 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) |
99 | { |
100 | pte_t *pte = pte_offset_kernel(pmd, addr); |
101 | if (pte_none(*pte)) { |
102 | pte_t entry; |
103 | void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); |
104 | if (!p) |
105 | return NULL; |
106 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); |
107 | set_pte_at(&init_mm, addr, pte, entry); |
108 | } |
109 | return pte; |
110 | } |
111 | |
112 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) |
113 | { |
114 | pmd_t *pmd = pmd_offset(pud, addr); |
115 | if (pmd_none(*pmd)) { |
116 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
117 | if (!p) |
118 | return NULL; |
119 | pmd_populate_kernel(&init_mm, pmd, p); |
120 | } |
121 | return pmd; |
122 | } |
123 | |
124 | pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) |
125 | { |
126 | pud_t *pud = pud_offset(pgd, addr); |
127 | if (pud_none(*pud)) { |
128 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
129 | if (!p) |
130 | return NULL; |
131 | pud_populate(&init_mm, pud, p); |
132 | } |
133 | return pud; |
134 | } |
135 | |
136 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) |
137 | { |
138 | pgd_t *pgd = pgd_offset_k(addr); |
139 | if (pgd_none(*pgd)) { |
140 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); |
141 | if (!p) |
142 | return NULL; |
143 | pgd_populate(&init_mm, pgd, p); |
144 | } |
145 | return pgd; |
146 | } |
147 | |
148 | int __meminit vmemmap_populate_basepages(struct page *start_page, |
149 | unsigned long size, int node) |
150 | { |
151 | unsigned long addr = (unsigned long)start_page; |
152 | unsigned long end = (unsigned long)(start_page + size); |
153 | pgd_t *pgd; |
154 | pud_t *pud; |
155 | pmd_t *pmd; |
156 | pte_t *pte; |
157 | |
158 | for (; addr < end; addr += PAGE_SIZE) { |
159 | pgd = vmemmap_pgd_populate(addr, node); |
160 | if (!pgd) |
161 | return -ENOMEM; |
162 | pud = vmemmap_pud_populate(pgd, addr, node); |
163 | if (!pud) |
164 | return -ENOMEM; |
165 | pmd = vmemmap_pmd_populate(pud, addr, node); |
166 | if (!pmd) |
167 | return -ENOMEM; |
168 | pte = vmemmap_pte_populate(pmd, addr, node); |
169 | if (!pte) |
170 | return -ENOMEM; |
171 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); |
172 | } |
173 | |
174 | return 0; |
175 | } |
176 | |
177 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) |
178 | { |
179 | struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); |
180 | int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); |
181 | if (error) |
182 | return NULL; |
183 | |
184 | return map; |
185 | } |
186 | |
187 | void __init sparse_mem_maps_populate_node(struct page **map_map, |
188 | unsigned long pnum_begin, |
189 | unsigned long pnum_end, |
190 | unsigned long map_count, int nodeid) |
191 | { |
192 | unsigned long pnum; |
193 | unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; |
194 | void *vmemmap_buf_start; |
195 | |
196 | size = ALIGN(size, PMD_SIZE); |
197 | vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, |
198 | PMD_SIZE, __pa(MAX_DMA_ADDRESS)); |
199 | |
200 | if (vmemmap_buf_start) { |
201 | vmemmap_buf = vmemmap_buf_start; |
202 | vmemmap_buf_end = vmemmap_buf_start + size * map_count; |
203 | } |
204 | |
205 | for (pnum = pnum_begin; pnum < pnum_end; pnum++) { |
206 | struct mem_section *ms; |
207 | |
208 | if (!present_section_nr(pnum)) |
209 | continue; |
210 | |
211 | map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); |
212 | if (map_map[pnum]) |
213 | continue; |
214 | ms = __nr_to_section(pnum); |
215 | printk(KERN_ERR "%s: sparsemem memory map backing failed " |
216 | "some memory will not be available.\n", __func__); |
217 | ms->section_mem_map = 0; |
218 | } |
219 | |
220 | if (vmemmap_buf_start) { |
221 | /* need to free left buf */ |
222 | free_bootmem(__pa(vmemmap_buf), vmemmap_buf_end - vmemmap_buf); |
223 | vmemmap_buf = NULL; |
224 | vmemmap_buf_end = NULL; |
225 | } |
226 | } |
227 |
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