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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 memmory 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 | } |