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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
38static 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
46static void *vmemmap_buf;
47static void *vmemmap_buf_end;
48
49void * __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 */
70void * __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
87void __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
98pte_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
112pmd_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
124pud_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
136pgd_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
148int __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
177struct 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
187void __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}