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