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/memremap.h> 24 #include <linux/highmem.h> 25 #include <linux/slab.h> 26 #include <linux/spinlock.h> 27 #include <linux/vmalloc.h> 28 #include <linux/sched.h> 29 #include <asm/dma.h> 30 #include <asm/pgalloc.h> 31 #include <asm/pgtable.h> 32 33 /* 34 * Allocate a block of memory to be used to back the virtual memory map 35 * or to back the page tables that are used to create the mapping. 36 * Uses the main allocators if they are available, else bootmem. 37 */ 38 39 static void * __ref __earlyonly_bootmem_alloc(int node, 40 unsigned long size, 41 unsigned long align, 42 unsigned long goal) 43 { 44 return memblock_virt_alloc_try_nid(size, align, goal, 45 BOOTMEM_ALLOC_ACCESSIBLE, node); 46 } 47 48 static void *vmemmap_buf; 49 static void *vmemmap_buf_end; 50 51 void * __meminit vmemmap_alloc_block(unsigned long size, int node) 52 { 53 /* If the main allocator is up use that, fallback to bootmem. */ 54 if (slab_is_available()) { 55 struct page *page; 56 57 if (node_state(node, N_HIGH_MEMORY)) 58 page = alloc_pages_node( 59 node, GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT, 60 get_order(size)); 61 else 62 page = alloc_pages( 63 GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT, 64 get_order(size)); 65 if (page) 66 return page_address(page); 67 return NULL; 68 } else 69 return __earlyonly_bootmem_alloc(node, size, size, 70 __pa(MAX_DMA_ADDRESS)); 71 } 72 73 /* need to make sure size is all the same during early stage */ 74 static void * __meminit alloc_block_buf(unsigned long size, int node) 75 { 76 void *ptr; 77 78 if (!vmemmap_buf) 79 return vmemmap_alloc_block(size, node); 80 81 /* take the from buf */ 82 ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); 83 if (ptr + size > vmemmap_buf_end) 84 return vmemmap_alloc_block(size, node); 85 86 vmemmap_buf = ptr + size; 87 88 return ptr; 89 } 90 91 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) 92 { 93 return altmap->base_pfn + altmap->reserve + altmap->alloc 94 + altmap->align; 95 } 96 97 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) 98 { 99 unsigned long allocated = altmap->alloc + altmap->align; 100 101 if (altmap->free > allocated) 102 return altmap->free - allocated; 103 return 0; 104 } 105 106 /** 107 * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation 108 * @altmap - reserved page pool for the allocation 109 * @nr_pfns - size (in pages) of the allocation 110 * 111 * Allocations are aligned to the size of the request 112 */ 113 static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap, 114 unsigned long nr_pfns) 115 { 116 unsigned long pfn = vmem_altmap_next_pfn(altmap); 117 unsigned long nr_align; 118 119 nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); 120 nr_align = ALIGN(pfn, nr_align) - pfn; 121 122 if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) 123 return ULONG_MAX; 124 altmap->alloc += nr_pfns; 125 altmap->align += nr_align; 126 return pfn + nr_align; 127 } 128 129 static void * __meminit altmap_alloc_block_buf(unsigned long size, 130 struct vmem_altmap *altmap) 131 { 132 unsigned long pfn, nr_pfns; 133 void *ptr; 134 135 if (size & ~PAGE_MASK) { 136 pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", 137 __func__, size); 138 return NULL; 139 } 140 141 nr_pfns = size >> PAGE_SHIFT; 142 pfn = vmem_altmap_alloc(altmap, nr_pfns); 143 if (pfn < ULONG_MAX) 144 ptr = __va(__pfn_to_phys(pfn)); 145 else 146 ptr = NULL; 147 pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", 148 __func__, pfn, altmap->alloc, altmap->align, nr_pfns); 149 150 return ptr; 151 } 152 153 /* need to make sure size is all the same during early stage */ 154 void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node, 155 struct vmem_altmap *altmap) 156 { 157 if (altmap) 158 return altmap_alloc_block_buf(size, altmap); 159 return alloc_block_buf(size, node); 160 } 161 162 void __meminit vmemmap_verify(pte_t *pte, int node, 163 unsigned long start, unsigned long end) 164 { 165 unsigned long pfn = pte_pfn(*pte); 166 int actual_node = early_pfn_to_nid(pfn); 167 168 if (node_distance(actual_node, node) > LOCAL_DISTANCE) 169 pr_warn("[%lx-%lx] potential offnode page_structs\n", 170 start, end - 1); 171 } 172 173 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) 174 { 175 pte_t *pte = pte_offset_kernel(pmd, addr); 176 if (pte_none(*pte)) { 177 pte_t entry; 178 void *p = alloc_block_buf(PAGE_SIZE, node); 179 if (!p) 180 return NULL; 181 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); 182 set_pte_at(&init_mm, addr, pte, entry); 183 } 184 return pte; 185 } 186 187 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) 188 { 189 pmd_t *pmd = pmd_offset(pud, addr); 190 if (pmd_none(*pmd)) { 191 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 192 if (!p) 193 return NULL; 194 pmd_populate_kernel(&init_mm, pmd, p); 195 } 196 return pmd; 197 } 198 199 pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) 200 { 201 pud_t *pud = pud_offset(pgd, addr); 202 if (pud_none(*pud)) { 203 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 204 if (!p) 205 return NULL; 206 pud_populate(&init_mm, pud, p); 207 } 208 return pud; 209 } 210 211 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 212 { 213 pgd_t *pgd = pgd_offset_k(addr); 214 if (pgd_none(*pgd)) { 215 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 216 if (!p) 217 return NULL; 218 pgd_populate(&init_mm, pgd, p); 219 } 220 return pgd; 221 } 222 223 int __meminit vmemmap_populate_basepages(unsigned long start, 224 unsigned long end, int node) 225 { 226 unsigned long addr = start; 227 pgd_t *pgd; 228 pud_t *pud; 229 pmd_t *pmd; 230 pte_t *pte; 231 232 for (; addr < end; addr += PAGE_SIZE) { 233 pgd = vmemmap_pgd_populate(addr, node); 234 if (!pgd) 235 return -ENOMEM; 236 pud = vmemmap_pud_populate(pgd, addr, node); 237 if (!pud) 238 return -ENOMEM; 239 pmd = vmemmap_pmd_populate(pud, addr, node); 240 if (!pmd) 241 return -ENOMEM; 242 pte = vmemmap_pte_populate(pmd, addr, node); 243 if (!pte) 244 return -ENOMEM; 245 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 246 } 247 248 return 0; 249 } 250 251 struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) 252 { 253 unsigned long start; 254 unsigned long end; 255 struct page *map; 256 257 map = pfn_to_page(pnum * PAGES_PER_SECTION); 258 start = (unsigned long)map; 259 end = (unsigned long)(map + PAGES_PER_SECTION); 260 261 if (vmemmap_populate(start, end, nid)) 262 return NULL; 263 264 return map; 265 } 266 267 void __init sparse_mem_maps_populate_node(struct page **map_map, 268 unsigned long pnum_begin, 269 unsigned long pnum_end, 270 unsigned long map_count, int nodeid) 271 { 272 unsigned long pnum; 273 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; 274 void *vmemmap_buf_start; 275 276 size = ALIGN(size, PMD_SIZE); 277 vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, 278 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 279 280 if (vmemmap_buf_start) { 281 vmemmap_buf = vmemmap_buf_start; 282 vmemmap_buf_end = vmemmap_buf_start + size * map_count; 283 } 284 285 for (pnum = pnum_begin; pnum < pnum_end; pnum++) { 286 struct mem_section *ms; 287 288 if (!present_section_nr(pnum)) 289 continue; 290 291 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); 292 if (map_map[pnum]) 293 continue; 294 ms = __nr_to_section(pnum); 295 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", 296 __func__); 297 ms->section_mem_map = 0; 298 } 299 300 if (vmemmap_buf_start) { 301 /* need to free left buf */ 302 memblock_free_early(__pa(vmemmap_buf), 303 vmemmap_buf_end - vmemmap_buf); 304 vmemmap_buf = NULL; 305 vmemmap_buf_end = NULL; 306 } 307 } 308