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( 57 node, GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT, 58 get_order(size)); 59 else 60 page = alloc_pages( 61 GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT, 62 get_order(size)); 63 if (page) 64 return page_address(page); 65 return NULL; 66 } else 67 return __earlyonly_bootmem_alloc(node, size, size, 68 __pa(MAX_DMA_ADDRESS)); 69 } 70 71 /* need to make sure size is all the same during early stage */ 72 void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) 73 { 74 void *ptr; 75 76 if (!vmemmap_buf) 77 return vmemmap_alloc_block(size, node); 78 79 /* take the from buf */ 80 ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); 81 if (ptr + size > vmemmap_buf_end) 82 return vmemmap_alloc_block(size, node); 83 84 vmemmap_buf = ptr + size; 85 86 return ptr; 87 } 88 89 void __meminit vmemmap_verify(pte_t *pte, int node, 90 unsigned long start, unsigned long end) 91 { 92 unsigned long pfn = pte_pfn(*pte); 93 int actual_node = early_pfn_to_nid(pfn); 94 95 if (node_distance(actual_node, node) > LOCAL_DISTANCE) 96 printk(KERN_WARNING "[%lx-%lx] potential offnode " 97 "page_structs\n", start, end - 1); 98 } 99 100 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) 101 { 102 pte_t *pte = pte_offset_kernel(pmd, addr); 103 if (pte_none(*pte)) { 104 pte_t entry; 105 void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); 106 if (!p) 107 return NULL; 108 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); 109 set_pte_at(&init_mm, addr, pte, entry); 110 } 111 return pte; 112 } 113 114 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) 115 { 116 pmd_t *pmd = pmd_offset(pud, addr); 117 if (pmd_none(*pmd)) { 118 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 119 if (!p) 120 return NULL; 121 pmd_populate_kernel(&init_mm, pmd, p); 122 } 123 return pmd; 124 } 125 126 pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) 127 { 128 pud_t *pud = pud_offset(pgd, addr); 129 if (pud_none(*pud)) { 130 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 131 if (!p) 132 return NULL; 133 pud_populate(&init_mm, pud, p); 134 } 135 return pud; 136 } 137 138 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 139 { 140 pgd_t *pgd = pgd_offset_k(addr); 141 if (pgd_none(*pgd)) { 142 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 143 if (!p) 144 return NULL; 145 pgd_populate(&init_mm, pgd, p); 146 } 147 return pgd; 148 } 149 150 int __meminit vmemmap_populate_basepages(unsigned long start, 151 unsigned long end, int node) 152 { 153 unsigned long addr = start; 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 unsigned long start; 181 unsigned long end; 182 struct page *map; 183 184 map = pfn_to_page(pnum * PAGES_PER_SECTION); 185 start = (unsigned long)map; 186 end = (unsigned long)(map + PAGES_PER_SECTION); 187 188 if (vmemmap_populate(start, end, nid)) 189 return NULL; 190 191 return map; 192 } 193 194 void __init sparse_mem_maps_populate_node(struct page **map_map, 195 unsigned long pnum_begin, 196 unsigned long pnum_end, 197 unsigned long map_count, int nodeid) 198 { 199 unsigned long pnum; 200 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; 201 void *vmemmap_buf_start; 202 203 size = ALIGN(size, PMD_SIZE); 204 vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, 205 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 206 207 if (vmemmap_buf_start) { 208 vmemmap_buf = vmemmap_buf_start; 209 vmemmap_buf_end = vmemmap_buf_start + size * map_count; 210 } 211 212 for (pnum = pnum_begin; pnum < pnum_end; pnum++) { 213 struct mem_section *ms; 214 215 if (!present_section_nr(pnum)) 216 continue; 217 218 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); 219 if (map_map[pnum]) 220 continue; 221 ms = __nr_to_section(pnum); 222 printk(KERN_ERR "%s: sparsemem memory map backing failed " 223 "some memory will not be available.\n", __func__); 224 ms->section_mem_map = 0; 225 } 226 227 if (vmemmap_buf_start) { 228 /* need to free left buf */ 229 free_bootmem(__pa(vmemmap_buf), vmemmap_buf_end - vmemmap_buf); 230 vmemmap_buf = NULL; 231 vmemmap_buf_end = NULL; 232 } 233 } 234