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8f6aac41 CL |
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 | * | |
29c71111 AW |
17 | * The architecture is expected to provide a vmemmap_populate() function |
18 | * to instantiate the mapping. | |
8f6aac41 CL |
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 <asm/dma.h> | |
28 | #include <asm/pgalloc.h> | |
29 | #include <asm/pgtable.h> | |
30 | ||
31 | /* | |
32 | * Allocate a block of memory to be used to back the virtual memory map | |
33 | * or to back the page tables that are used to create the mapping. | |
34 | * Uses the main allocators if they are available, else bootmem. | |
35 | */ | |
36 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) | |
37 | { | |
38 | /* If the main allocator is up use that, fallback to bootmem. */ | |
39 | if (slab_is_available()) { | |
40 | struct page *page = alloc_pages_node(node, | |
41 | GFP_KERNEL | __GFP_ZERO, get_order(size)); | |
42 | if (page) | |
43 | return page_address(page); | |
44 | return NULL; | |
45 | } else | |
46 | return __alloc_bootmem_node(NODE_DATA(node), size, size, | |
47 | __pa(MAX_DMA_ADDRESS)); | |
48 | } | |
49 | ||
8f6aac41 CL |
50 | void __meminit vmemmap_verify(pte_t *pte, int node, |
51 | unsigned long start, unsigned long end) | |
52 | { | |
53 | unsigned long pfn = pte_pfn(*pte); | |
54 | int actual_node = early_pfn_to_nid(pfn); | |
55 | ||
56 | if (actual_node != node) | |
57 | printk(KERN_WARNING "[%lx-%lx] potential offnode " | |
58 | "page_structs\n", start, end - 1); | |
59 | } | |
60 | ||
29c71111 | 61 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) |
8f6aac41 | 62 | { |
29c71111 AW |
63 | pte_t *pte = pte_offset_kernel(pmd, addr); |
64 | if (pte_none(*pte)) { | |
65 | pte_t entry; | |
66 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
67 | if (!p) | |
68 | return 0; | |
69 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); | |
70 | set_pte_at(&init_mm, addr, pte, entry); | |
71 | } | |
72 | return pte; | |
8f6aac41 CL |
73 | } |
74 | ||
29c71111 | 75 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) |
8f6aac41 | 76 | { |
29c71111 AW |
77 | pmd_t *pmd = pmd_offset(pud, addr); |
78 | if (pmd_none(*pmd)) { | |
79 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
80 | if (!p) | |
81 | return 0; | |
82 | pmd_populate_kernel(&init_mm, pmd, p); | |
8f6aac41 | 83 | } |
29c71111 | 84 | return pmd; |
8f6aac41 | 85 | } |
8f6aac41 | 86 | |
29c71111 | 87 | pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) |
8f6aac41 | 88 | { |
29c71111 AW |
89 | pud_t *pud = pud_offset(pgd, addr); |
90 | if (pud_none(*pud)) { | |
91 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
92 | if (!p) | |
93 | return 0; | |
94 | pud_populate(&init_mm, pud, p); | |
95 | } | |
96 | return pud; | |
97 | } | |
8f6aac41 | 98 | |
29c71111 AW |
99 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) |
100 | { | |
101 | pgd_t *pgd = pgd_offset_k(addr); | |
102 | if (pgd_none(*pgd)) { | |
103 | void *p = vmemmap_alloc_block(PAGE_SIZE, node); | |
104 | if (!p) | |
105 | return 0; | |
106 | pgd_populate(&init_mm, pgd, p); | |
8f6aac41 | 107 | } |
29c71111 | 108 | return pgd; |
8f6aac41 CL |
109 | } |
110 | ||
29c71111 AW |
111 | int __meminit vmemmap_populate_basepages(struct page *start_page, |
112 | unsigned long size, int node) | |
8f6aac41 | 113 | { |
8f6aac41 | 114 | unsigned long addr = (unsigned long)start_page; |
29c71111 AW |
115 | unsigned long end = (unsigned long)(start_page + size); |
116 | pgd_t *pgd; | |
117 | pud_t *pud; | |
118 | pmd_t *pmd; | |
119 | pte_t *pte; | |
8f6aac41 | 120 | |
29c71111 AW |
121 | for (; addr < end; addr += PAGE_SIZE) { |
122 | pgd = vmemmap_pgd_populate(addr, node); | |
123 | if (!pgd) | |
124 | return -ENOMEM; | |
125 | pud = vmemmap_pud_populate(pgd, addr, node); | |
126 | if (!pud) | |
127 | return -ENOMEM; | |
128 | pmd = vmemmap_pmd_populate(pud, addr, node); | |
129 | if (!pmd) | |
130 | return -ENOMEM; | |
131 | pte = vmemmap_pte_populate(pmd, addr, node); | |
132 | if (!pte) | |
133 | return -ENOMEM; | |
134 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); | |
8f6aac41 | 135 | } |
29c71111 AW |
136 | |
137 | return 0; | |
8f6aac41 | 138 | } |
8f6aac41 | 139 | |
98f3cfc1 | 140 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) |
8f6aac41 CL |
141 | { |
142 | struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); | |
143 | int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); | |
144 | if (error) | |
145 | return NULL; | |
146 | ||
147 | return map; | |
148 | } |