1 /* 2 * sparse memory mappings. 3 */ 4 #include <linux/config.h> 5 #include <linux/mm.h> 6 #include <linux/mmzone.h> 7 #include <linux/bootmem.h> 8 #include <linux/highmem.h> 9 #include <linux/module.h> 10 #include <linux/spinlock.h> 11 #include <linux/vmalloc.h> 12 #include <asm/dma.h> 13 14 /* 15 * Permanent SPARSEMEM data: 16 * 17 * 1) mem_section - memory sections, mem_map's for valid memory 18 */ 19 #ifdef CONFIG_SPARSEMEM_EXTREME 20 struct mem_section *mem_section[NR_SECTION_ROOTS] 21 ____cacheline_internodealigned_in_smp; 22 #else 23 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] 24 ____cacheline_internodealigned_in_smp; 25 #endif 26 EXPORT_SYMBOL(mem_section); 27 28 #ifdef CONFIG_SPARSEMEM_EXTREME 29 static struct mem_section *sparse_index_alloc(int nid) 30 { 31 struct mem_section *section = NULL; 32 unsigned long array_size = SECTIONS_PER_ROOT * 33 sizeof(struct mem_section); 34 35 if (slab_is_available()) 36 section = kmalloc_node(array_size, GFP_KERNEL, nid); 37 else 38 section = alloc_bootmem_node(NODE_DATA(nid), array_size); 39 40 if (section) 41 memset(section, 0, array_size); 42 43 return section; 44 } 45 46 static int sparse_index_init(unsigned long section_nr, int nid) 47 { 48 static DEFINE_SPINLOCK(index_init_lock); 49 unsigned long root = SECTION_NR_TO_ROOT(section_nr); 50 struct mem_section *section; 51 int ret = 0; 52 53 if (mem_section[root]) 54 return -EEXIST; 55 56 section = sparse_index_alloc(nid); 57 /* 58 * This lock keeps two different sections from 59 * reallocating for the same index 60 */ 61 spin_lock(&index_init_lock); 62 63 if (mem_section[root]) { 64 ret = -EEXIST; 65 goto out; 66 } 67 68 mem_section[root] = section; 69 out: 70 spin_unlock(&index_init_lock); 71 return ret; 72 } 73 #else /* !SPARSEMEM_EXTREME */ 74 static inline int sparse_index_init(unsigned long section_nr, int nid) 75 { 76 return 0; 77 } 78 #endif 79 80 /* 81 * Although written for the SPARSEMEM_EXTREME case, this happens 82 * to also work for the flat array case becase 83 * NR_SECTION_ROOTS==NR_MEM_SECTIONS. 84 */ 85 int __section_nr(struct mem_section* ms) 86 { 87 unsigned long root_nr; 88 struct mem_section* root; 89 90 for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { 91 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); 92 if (!root) 93 continue; 94 95 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) 96 break; 97 } 98 99 return (root_nr * SECTIONS_PER_ROOT) + (ms - root); 100 } 101 102 /* 103 * During early boot, before section_mem_map is used for an actual 104 * mem_map, we use section_mem_map to store the section's NUMA 105 * node. This keeps us from having to use another data structure. The 106 * node information is cleared just before we store the real mem_map. 107 */ 108 static inline unsigned long sparse_encode_early_nid(int nid) 109 { 110 return (nid << SECTION_NID_SHIFT); 111 } 112 113 static inline int sparse_early_nid(struct mem_section *section) 114 { 115 return (section->section_mem_map >> SECTION_NID_SHIFT); 116 } 117 118 /* Record a memory area against a node. */ 119 void memory_present(int nid, unsigned long start, unsigned long end) 120 { 121 unsigned long pfn; 122 123 start &= PAGE_SECTION_MASK; 124 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { 125 unsigned long section = pfn_to_section_nr(pfn); 126 struct mem_section *ms; 127 128 sparse_index_init(section, nid); 129 130 ms = __nr_to_section(section); 131 if (!ms->section_mem_map) 132 ms->section_mem_map = sparse_encode_early_nid(nid) | 133 SECTION_MARKED_PRESENT; 134 } 135 } 136 137 /* 138 * Only used by the i386 NUMA architecures, but relatively 139 * generic code. 140 */ 141 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn, 142 unsigned long end_pfn) 143 { 144 unsigned long pfn; 145 unsigned long nr_pages = 0; 146 147 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 148 if (nid != early_pfn_to_nid(pfn)) 149 continue; 150 151 if (pfn_valid(pfn)) 152 nr_pages += PAGES_PER_SECTION; 153 } 154 155 return nr_pages * sizeof(struct page); 156 } 157 158 /* 159 * Subtle, we encode the real pfn into the mem_map such that 160 * the identity pfn - section_mem_map will return the actual 161 * physical page frame number. 162 */ 163 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) 164 { 165 return (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); 166 } 167 168 /* 169 * We need this if we ever free the mem_maps. While not implemented yet, 170 * this function is included for parity with its sibling. 171 */ 172 static __attribute((unused)) 173 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) 174 { 175 return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); 176 } 177 178 static int sparse_init_one_section(struct mem_section *ms, 179 unsigned long pnum, struct page *mem_map) 180 { 181 if (!valid_section(ms)) 182 return -EINVAL; 183 184 ms->section_mem_map &= ~SECTION_MAP_MASK; 185 ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum); 186 187 return 1; 188 } 189 190 static struct page *sparse_early_mem_map_alloc(unsigned long pnum) 191 { 192 struct page *map; 193 struct mem_section *ms = __nr_to_section(pnum); 194 int nid = sparse_early_nid(ms); 195 196 map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); 197 if (map) 198 return map; 199 200 map = alloc_bootmem_node(NODE_DATA(nid), 201 sizeof(struct page) * PAGES_PER_SECTION); 202 if (map) 203 return map; 204 205 printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__); 206 ms->section_mem_map = 0; 207 return NULL; 208 } 209 210 static struct page *__kmalloc_section_memmap(unsigned long nr_pages) 211 { 212 struct page *page, *ret; 213 unsigned long memmap_size = sizeof(struct page) * nr_pages; 214 215 page = alloc_pages(GFP_KERNEL, get_order(memmap_size)); 216 if (page) 217 goto got_map_page; 218 219 ret = vmalloc(memmap_size); 220 if (ret) 221 goto got_map_ptr; 222 223 return NULL; 224 got_map_page: 225 ret = (struct page *)pfn_to_kaddr(page_to_pfn(page)); 226 got_map_ptr: 227 memset(ret, 0, memmap_size); 228 229 return ret; 230 } 231 232 static int vaddr_in_vmalloc_area(void *addr) 233 { 234 if (addr >= (void *)VMALLOC_START && 235 addr < (void *)VMALLOC_END) 236 return 1; 237 return 0; 238 } 239 240 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages) 241 { 242 if (vaddr_in_vmalloc_area(memmap)) 243 vfree(memmap); 244 else 245 free_pages((unsigned long)memmap, 246 get_order(sizeof(struct page) * nr_pages)); 247 } 248 249 /* 250 * Allocate the accumulated non-linear sections, allocate a mem_map 251 * for each and record the physical to section mapping. 252 */ 253 void sparse_init(void) 254 { 255 unsigned long pnum; 256 struct page *map; 257 258 for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { 259 if (!valid_section_nr(pnum)) 260 continue; 261 262 map = sparse_early_mem_map_alloc(pnum); 263 if (!map) 264 continue; 265 sparse_init_one_section(__nr_to_section(pnum), pnum, map); 266 } 267 } 268 269 /* 270 * returns the number of sections whose mem_maps were properly 271 * set. If this is <=0, then that means that the passed-in 272 * map was not consumed and must be freed. 273 */ 274 int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, 275 int nr_pages) 276 { 277 unsigned long section_nr = pfn_to_section_nr(start_pfn); 278 struct pglist_data *pgdat = zone->zone_pgdat; 279 struct mem_section *ms; 280 struct page *memmap; 281 unsigned long flags; 282 int ret; 283 284 /* 285 * no locking for this, because it does its own 286 * plus, it does a kmalloc 287 */ 288 sparse_index_init(section_nr, pgdat->node_id); 289 memmap = __kmalloc_section_memmap(nr_pages); 290 291 pgdat_resize_lock(pgdat, &flags); 292 293 ms = __pfn_to_section(start_pfn); 294 if (ms->section_mem_map & SECTION_MARKED_PRESENT) { 295 ret = -EEXIST; 296 goto out; 297 } 298 ms->section_mem_map |= SECTION_MARKED_PRESENT; 299 300 ret = sparse_init_one_section(ms, section_nr, memmap); 301 302 out: 303 pgdat_resize_unlock(pgdat, &flags); 304 if (ret <= 0) 305 __kfree_section_memmap(memmap, nr_pages); 306 return ret; 307 } 308