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(p4d_t *p4d, unsigned long addr, int node) 200 { 201 pud_t *pud = pud_offset(p4d, 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 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) 212 { 213 p4d_t *p4d = p4d_offset(pgd, addr); 214 if (p4d_none(*p4d)) { 215 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 216 if (!p) 217 return NULL; 218 p4d_populate(&init_mm, p4d, p); 219 } 220 return p4d; 221 } 222 223 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 224 { 225 pgd_t *pgd = pgd_offset_k(addr); 226 if (pgd_none(*pgd)) { 227 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 228 if (!p) 229 return NULL; 230 pgd_populate(&init_mm, pgd, p); 231 } 232 return pgd; 233 } 234 235 int __meminit vmemmap_populate_basepages(unsigned long start, 236 unsigned long end, int node) 237 { 238 unsigned long addr = start; 239 pgd_t *pgd; 240 p4d_t *p4d; 241 pud_t *pud; 242 pmd_t *pmd; 243 pte_t *pte; 244 245 for (; addr < end; addr += PAGE_SIZE) { 246 pgd = vmemmap_pgd_populate(addr, node); 247 if (!pgd) 248 return -ENOMEM; 249 p4d = vmemmap_p4d_populate(pgd, addr, node); 250 if (!p4d) 251 return -ENOMEM; 252 pud = vmemmap_pud_populate(p4d, addr, node); 253 if (!pud) 254 return -ENOMEM; 255 pmd = vmemmap_pmd_populate(pud, addr, node); 256 if (!pmd) 257 return -ENOMEM; 258 pte = vmemmap_pte_populate(pmd, addr, node); 259 if (!pte) 260 return -ENOMEM; 261 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 262 } 263 264 return 0; 265 } 266 267 struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) 268 { 269 unsigned long start; 270 unsigned long end; 271 struct page *map; 272 273 map = pfn_to_page(pnum * PAGES_PER_SECTION); 274 start = (unsigned long)map; 275 end = (unsigned long)(map + PAGES_PER_SECTION); 276 277 if (vmemmap_populate(start, end, nid)) 278 return NULL; 279 280 return map; 281 } 282 283 void __init sparse_mem_maps_populate_node(struct page **map_map, 284 unsigned long pnum_begin, 285 unsigned long pnum_end, 286 unsigned long map_count, int nodeid) 287 { 288 unsigned long pnum; 289 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; 290 void *vmemmap_buf_start; 291 292 size = ALIGN(size, PMD_SIZE); 293 vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, 294 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 295 296 if (vmemmap_buf_start) { 297 vmemmap_buf = vmemmap_buf_start; 298 vmemmap_buf_end = vmemmap_buf_start + size * map_count; 299 } 300 301 for (pnum = pnum_begin; pnum < pnum_end; pnum++) { 302 struct mem_section *ms; 303 304 if (!present_section_nr(pnum)) 305 continue; 306 307 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); 308 if (map_map[pnum]) 309 continue; 310 ms = __nr_to_section(pnum); 311 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", 312 __func__); 313 ms->section_mem_map = 0; 314 } 315 316 if (vmemmap_buf_start) { 317 /* need to free left buf */ 318 memblock_free_early(__pa(vmemmap_buf), 319 vmemmap_buf_end - vmemmap_buf); 320 vmemmap_buf = NULL; 321 vmemmap_buf_end = NULL; 322 } 323 } 324