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1 | /* | |
2 | * Virtual Memory Map support | |
3 | * | |
4 | * (C) 2007 sgi. Christoph Lameter <clameter@sgi.com>. | |
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/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(NODE_DATA(node), size, align, goal); | |
44 | } | |
45 | ||
46 | ||
47 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) | |
48 | { | |
49 | /* If the main allocator is up use that, fallback to bootmem. */ | |
50 | if (slab_is_available()) { | |
51 | struct page *page = alloc_pages_node(node, | |
52 | GFP_KERNEL | __GFP_ZERO, get_order(size)); | |
53 | if (page) | |
54 | return page_address(page); | |
55 | return NULL; | |
56 | } else | |
57 | return __earlyonly_bootmem_alloc(node, size, size, | |
58 | __pa(MAX_DMA_ADDRESS)); | |
59 | } | |
60 | ||
61 | void __meminit vmemmap_verify(pte_t *pte, int node, | |
62 | unsigned long start, unsigned long end) | |
63 | { | |
64 | unsigned long pfn = pte_pfn(*pte); | |
65 | int actual_node = early_pfn_to_nid(pfn); | |
66 | ||
67 | if (actual_node != node) | |
68 | printk(KERN_WARNING "[%lx-%lx] potential offnode " | |
69 | "page_structs\n", start, end - 1); | |
70 | } | |
71 | ||
72 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) | |
73 | { | |
74 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
75 | if (pte_none(*pte)) { | |
76 | pte_t entry; | |
77 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
78 | if (!p) | |
79 | return NULL; | |
80 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); | |
81 | set_pte_at(&init_mm, addr, pte, entry); | |
82 | } | |
83 | return pte; | |
84 | } | |
85 | ||
86 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) | |
87 | { | |
88 | pmd_t *pmd = pmd_offset(pud, addr); | |
89 | if (pmd_none(*pmd)) { | |
90 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
91 | if (!p) | |
92 | return NULL; | |
93 | pmd_populate_kernel(&init_mm, pmd, p); | |
94 | } | |
95 | return pmd; | |
96 | } | |
97 | ||
98 | pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) | |
99 | { | |
100 | pud_t *pud = pud_offset(pgd, addr); | |
101 | if (pud_none(*pud)) { | |
102 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
103 | if (!p) | |
104 | return NULL; | |
105 | pud_populate(&init_mm, pud, p); | |
106 | } | |
107 | return pud; | |
108 | } | |
109 | ||
110 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) | |
111 | { | |
112 | pgd_t *pgd = pgd_offset_k(addr); | |
113 | if (pgd_none(*pgd)) { | |
114 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
115 | if (!p) | |
116 | return NULL; | |
117 | pgd_populate(&init_mm, pgd, p); | |
118 | } | |
119 | return pgd; | |
120 | } | |
121 | ||
122 | int __meminit vmemmap_populate_basepages(struct page *start_page, | |
123 | unsigned long size, int node) | |
124 | { | |
125 | unsigned long addr = (unsigned long)start_page; | |
126 | unsigned long end = (unsigned long)(start_page + size); | |
127 | pgd_t *pgd; | |
128 | pud_t *pud; | |
129 | pmd_t *pmd; | |
130 | pte_t *pte; | |
131 | ||
132 | for (; addr < end; addr += PAGE_SIZE) { | |
133 | pgd = vmemmap_pgd_populate(addr, node); | |
134 | if (!pgd) | |
135 | return -ENOMEM; | |
136 | pud = vmemmap_pud_populate(pgd, addr, node); | |
137 | if (!pud) | |
138 | return -ENOMEM; | |
139 | pmd = vmemmap_pmd_populate(pud, addr, node); | |
140 | if (!pmd) | |
141 | return -ENOMEM; | |
142 | pte = vmemmap_pte_populate(pmd, addr, node); | |
143 | if (!pte) | |
144 | return -ENOMEM; | |
145 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); | |
146 | } | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) | |
152 | { | |
153 | struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); | |
154 | int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); | |
155 | if (error) | |
156 | return NULL; | |
157 | ||
158 | return map; | |
159 | } |