1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Virtual Memory Map support 4 * 5 * (C) 2007 sgi. Christoph Lameter. 6 * 7 * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn, 8 * virt_to_page, page_address() to be implemented as a base offset 9 * calculation without memory access. 10 * 11 * However, virtual mappings need a page table and TLBs. Many Linux 12 * architectures already map their physical space using 1-1 mappings 13 * via TLBs. For those arches the virtual memory map is essentially 14 * for free if we use the same page size as the 1-1 mappings. In that 15 * case the overhead consists of a few additional pages that are 16 * allocated to create a view of memory for vmemmap. 17 * 18 * The architecture is expected to provide a vmemmap_populate() function 19 * to instantiate the mapping. 20 */ 21 #include <linux/mm.h> 22 #include <linux/mmzone.h> 23 #include <linux/bootmem.h> 24 #include <linux/memremap.h> 25 #include <linux/highmem.h> 26 #include <linux/slab.h> 27 #include <linux/spinlock.h> 28 #include <linux/vmalloc.h> 29 #include <linux/sched.h> 30 #include <asm/dma.h> 31 #include <asm/pgalloc.h> 32 #include <asm/pgtable.h> 33 34 /* 35 * Allocate a block of memory to be used to back the virtual memory map 36 * or to back the page tables that are used to create the mapping. 37 * Uses the main allocators if they are available, else bootmem. 38 */ 39 40 static void * __ref __earlyonly_bootmem_alloc(int node, 41 unsigned long size, 42 unsigned long align, 43 unsigned long goal) 44 { 45 return memblock_virt_alloc_try_nid_raw(size, align, goal, 46 BOOTMEM_ALLOC_ACCESSIBLE, node); 47 } 48 49 static void *vmemmap_buf; 50 static void *vmemmap_buf_end; 51 52 void * __meminit vmemmap_alloc_block(unsigned long size, int node) 53 { 54 /* If the main allocator is up use that, fallback to bootmem. */ 55 if (slab_is_available()) { 56 struct page *page; 57 58 page = alloc_pages_node(node, GFP_KERNEL | __GFP_RETRY_MAYFAIL, 59 get_order(size)); 60 if (page) 61 return page_address(page); 62 return NULL; 63 } else 64 return __earlyonly_bootmem_alloc(node, size, size, 65 __pa(MAX_DMA_ADDRESS)); 66 } 67 68 /* need to make sure size is all the same during early stage */ 69 static void * __meminit alloc_block_buf(unsigned long size, int node) 70 { 71 void *ptr; 72 73 if (!vmemmap_buf) 74 return vmemmap_alloc_block(size, node); 75 76 /* take the from buf */ 77 ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); 78 if (ptr + size > vmemmap_buf_end) 79 return vmemmap_alloc_block(size, node); 80 81 vmemmap_buf = ptr + size; 82 83 return ptr; 84 } 85 86 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) 87 { 88 return altmap->base_pfn + altmap->reserve + altmap->alloc 89 + altmap->align; 90 } 91 92 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) 93 { 94 unsigned long allocated = altmap->alloc + altmap->align; 95 96 if (altmap->free > allocated) 97 return altmap->free - allocated; 98 return 0; 99 } 100 101 /** 102 * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation 103 * @altmap - reserved page pool for the allocation 104 * @nr_pfns - size (in pages) of the allocation 105 * 106 * Allocations are aligned to the size of the request 107 */ 108 static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap, 109 unsigned long nr_pfns) 110 { 111 unsigned long pfn = vmem_altmap_next_pfn(altmap); 112 unsigned long nr_align; 113 114 nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); 115 nr_align = ALIGN(pfn, nr_align) - pfn; 116 117 if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) 118 return ULONG_MAX; 119 altmap->alloc += nr_pfns; 120 altmap->align += nr_align; 121 return pfn + nr_align; 122 } 123 124 static void * __meminit altmap_alloc_block_buf(unsigned long size, 125 struct vmem_altmap *altmap) 126 { 127 unsigned long pfn, nr_pfns; 128 void *ptr; 129 130 if (size & ~PAGE_MASK) { 131 pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", 132 __func__, size); 133 return NULL; 134 } 135 136 nr_pfns = size >> PAGE_SHIFT; 137 pfn = vmem_altmap_alloc(altmap, nr_pfns); 138 if (pfn < ULONG_MAX) 139 ptr = __va(__pfn_to_phys(pfn)); 140 else 141 ptr = NULL; 142 pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", 143 __func__, pfn, altmap->alloc, altmap->align, nr_pfns); 144 145 return ptr; 146 } 147 148 /* need to make sure size is all the same during early stage */ 149 void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node, 150 struct vmem_altmap *altmap) 151 { 152 if (altmap) 153 return altmap_alloc_block_buf(size, altmap); 154 return alloc_block_buf(size, node); 155 } 156 157 void __meminit vmemmap_verify(pte_t *pte, int node, 158 unsigned long start, unsigned long end) 159 { 160 unsigned long pfn = pte_pfn(*pte); 161 int actual_node = early_pfn_to_nid(pfn); 162 163 if (node_distance(actual_node, node) > LOCAL_DISTANCE) 164 pr_warn("[%lx-%lx] potential offnode page_structs\n", 165 start, end - 1); 166 } 167 168 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) 169 { 170 pte_t *pte = pte_offset_kernel(pmd, addr); 171 if (pte_none(*pte)) { 172 pte_t entry; 173 void *p = alloc_block_buf(PAGE_SIZE, node); 174 if (!p) 175 return NULL; 176 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); 177 set_pte_at(&init_mm, addr, pte, entry); 178 } 179 return pte; 180 } 181 182 static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) 183 { 184 void *p = vmemmap_alloc_block(size, node); 185 186 if (!p) 187 return NULL; 188 memset(p, 0, size); 189 190 return p; 191 } 192 193 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) 194 { 195 pmd_t *pmd = pmd_offset(pud, addr); 196 if (pmd_none(*pmd)) { 197 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 198 if (!p) 199 return NULL; 200 pmd_populate_kernel(&init_mm, pmd, p); 201 } 202 return pmd; 203 } 204 205 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) 206 { 207 pud_t *pud = pud_offset(p4d, addr); 208 if (pud_none(*pud)) { 209 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 210 if (!p) 211 return NULL; 212 pud_populate(&init_mm, pud, p); 213 } 214 return pud; 215 } 216 217 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) 218 { 219 p4d_t *p4d = p4d_offset(pgd, addr); 220 if (p4d_none(*p4d)) { 221 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 222 if (!p) 223 return NULL; 224 p4d_populate(&init_mm, p4d, p); 225 } 226 return p4d; 227 } 228 229 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 230 { 231 pgd_t *pgd = pgd_offset_k(addr); 232 if (pgd_none(*pgd)) { 233 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 234 if (!p) 235 return NULL; 236 pgd_populate(&init_mm, pgd, p); 237 } 238 return pgd; 239 } 240 241 int __meminit vmemmap_populate_basepages(unsigned long start, 242 unsigned long end, int node) 243 { 244 unsigned long addr = start; 245 pgd_t *pgd; 246 p4d_t *p4d; 247 pud_t *pud; 248 pmd_t *pmd; 249 pte_t *pte; 250 251 for (; addr < end; addr += PAGE_SIZE) { 252 pgd = vmemmap_pgd_populate(addr, node); 253 if (!pgd) 254 return -ENOMEM; 255 p4d = vmemmap_p4d_populate(pgd, addr, node); 256 if (!p4d) 257 return -ENOMEM; 258 pud = vmemmap_pud_populate(p4d, addr, node); 259 if (!pud) 260 return -ENOMEM; 261 pmd = vmemmap_pmd_populate(pud, addr, node); 262 if (!pmd) 263 return -ENOMEM; 264 pte = vmemmap_pte_populate(pmd, addr, node); 265 if (!pte) 266 return -ENOMEM; 267 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 268 } 269 270 return 0; 271 } 272 273 struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) 274 { 275 unsigned long start; 276 unsigned long end; 277 struct page *map; 278 279 map = pfn_to_page(pnum * PAGES_PER_SECTION); 280 start = (unsigned long)map; 281 end = (unsigned long)(map + PAGES_PER_SECTION); 282 283 if (vmemmap_populate(start, end, nid)) 284 return NULL; 285 286 return map; 287 } 288 289 void __init sparse_mem_maps_populate_node(struct page **map_map, 290 unsigned long pnum_begin, 291 unsigned long pnum_end, 292 unsigned long map_count, int nodeid) 293 { 294 unsigned long pnum; 295 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; 296 void *vmemmap_buf_start; 297 298 size = ALIGN(size, PMD_SIZE); 299 vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, 300 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 301 302 if (vmemmap_buf_start) { 303 vmemmap_buf = vmemmap_buf_start; 304 vmemmap_buf_end = vmemmap_buf_start + size * map_count; 305 } 306 307 for (pnum = pnum_begin; pnum < pnum_end; pnum++) { 308 struct mem_section *ms; 309 310 if (!present_section_nr(pnum)) 311 continue; 312 313 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); 314 if (map_map[pnum]) 315 continue; 316 ms = __nr_to_section(pnum); 317 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", 318 __func__); 319 ms->section_mem_map = 0; 320 } 321 322 if (vmemmap_buf_start) { 323 /* need to free left buf */ 324 memblock_free_early(__pa(vmemmap_buf), 325 vmemmap_buf_end - vmemmap_buf); 326 vmemmap_buf = NULL; 327 vmemmap_buf_end = NULL; 328 } 329 } 330