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(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 */ 70 void * __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 87 void __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 98 pte_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 } 111 112 pmd_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 } 123 124 pud_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 } 135 136 pgd_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 } 147 148 int __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 } 176 177 struct 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 } 186 187 void __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 } 227