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/module.h> 9 #include <linux/spinlock.h> 10 #include <asm/dma.h> 11 12 /* 13 * Permanent SPARSEMEM data: 14 * 15 * 1) mem_section - memory sections, mem_map's for valid memory 16 */ 17 #ifdef CONFIG_SPARSEMEM_EXTREME 18 struct mem_section *mem_section[NR_SECTION_ROOTS] 19 ____cacheline_maxaligned_in_smp; 20 #else 21 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] 22 ____cacheline_maxaligned_in_smp; 23 #endif 24 EXPORT_SYMBOL(mem_section); 25 26 #ifdef CONFIG_SPARSEMEM_EXTREME 27 static struct mem_section *sparse_index_alloc(int nid) 28 { 29 struct mem_section *section = NULL; 30 unsigned long array_size = SECTIONS_PER_ROOT * 31 sizeof(struct mem_section); 32 33 section = alloc_bootmem_node(NODE_DATA(nid), array_size); 34 35 if (section) 36 memset(section, 0, array_size); 37 38 return section; 39 } 40 41 static int sparse_index_init(unsigned long section_nr, int nid) 42 { 43 static spinlock_t index_init_lock = SPIN_LOCK_UNLOCKED; 44 unsigned long root = SECTION_NR_TO_ROOT(section_nr); 45 struct mem_section *section; 46 int ret = 0; 47 48 if (mem_section[root]) 49 return -EEXIST; 50 51 section = sparse_index_alloc(nid); 52 /* 53 * This lock keeps two different sections from 54 * reallocating for the same index 55 */ 56 spin_lock(&index_init_lock); 57 58 if (mem_section[root]) { 59 ret = -EEXIST; 60 goto out; 61 } 62 63 mem_section[root] = section; 64 out: 65 spin_unlock(&index_init_lock); 66 return ret; 67 } 68 #else /* !SPARSEMEM_EXTREME */ 69 static inline int sparse_index_init(unsigned long section_nr, int nid) 70 { 71 return 0; 72 } 73 #endif 74 75 /* Record a memory area against a node. */ 76 void memory_present(int nid, unsigned long start, unsigned long end) 77 { 78 unsigned long pfn; 79 80 start &= PAGE_SECTION_MASK; 81 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { 82 unsigned long section = pfn_to_section_nr(pfn); 83 struct mem_section *ms; 84 85 sparse_index_init(section, nid); 86 87 ms = __nr_to_section(section); 88 if (!ms->section_mem_map) 89 ms->section_mem_map = SECTION_MARKED_PRESENT; 90 } 91 } 92 93 /* 94 * Only used by the i386 NUMA architecures, but relatively 95 * generic code. 96 */ 97 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn, 98 unsigned long end_pfn) 99 { 100 unsigned long pfn; 101 unsigned long nr_pages = 0; 102 103 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 104 if (nid != early_pfn_to_nid(pfn)) 105 continue; 106 107 if (pfn_valid(pfn)) 108 nr_pages += PAGES_PER_SECTION; 109 } 110 111 return nr_pages * sizeof(struct page); 112 } 113 114 /* 115 * Subtle, we encode the real pfn into the mem_map such that 116 * the identity pfn - section_mem_map will return the actual 117 * physical page frame number. 118 */ 119 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) 120 { 121 return (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); 122 } 123 124 /* 125 * We need this if we ever free the mem_maps. While not implemented yet, 126 * this function is included for parity with its sibling. 127 */ 128 static __attribute((unused)) 129 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) 130 { 131 return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); 132 } 133 134 static int sparse_init_one_section(struct mem_section *ms, 135 unsigned long pnum, struct page *mem_map) 136 { 137 if (!valid_section(ms)) 138 return -EINVAL; 139 140 ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum); 141 142 return 1; 143 } 144 145 static struct page *sparse_early_mem_map_alloc(unsigned long pnum) 146 { 147 struct page *map; 148 int nid = early_pfn_to_nid(section_nr_to_pfn(pnum)); 149 struct mem_section *ms = __nr_to_section(pnum); 150 151 map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); 152 if (map) 153 return map; 154 155 map = alloc_bootmem_node(NODE_DATA(nid), 156 sizeof(struct page) * PAGES_PER_SECTION); 157 if (map) 158 return map; 159 160 printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__); 161 ms->section_mem_map = 0; 162 return NULL; 163 } 164 165 /* 166 * Allocate the accumulated non-linear sections, allocate a mem_map 167 * for each and record the physical to section mapping. 168 */ 169 void sparse_init(void) 170 { 171 unsigned long pnum; 172 struct page *map; 173 174 for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { 175 if (!valid_section_nr(pnum)) 176 continue; 177 178 map = sparse_early_mem_map_alloc(pnum); 179 if (!map) 180 continue; 181 sparse_init_one_section(__nr_to_section(pnum), pnum, map); 182 } 183 } 184 185 /* 186 * returns the number of sections whose mem_maps were properly 187 * set. If this is <=0, then that means that the passed-in 188 * map was not consumed and must be freed. 189 */ 190 int sparse_add_one_section(unsigned long start_pfn, int nr_pages, struct page *map) 191 { 192 struct mem_section *ms = __pfn_to_section(start_pfn); 193 194 if (ms->section_mem_map & SECTION_MARKED_PRESENT) 195 return -EEXIST; 196 197 ms->section_mem_map |= SECTION_MARKED_PRESENT; 198 199 return sparse_init_one_section(ms, pfn_to_section_nr(start_pfn), map); 200 } 201