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(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, 59 GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL, 60 get_order(size)); 61 if (page) 62 return page_address(page); 63 return NULL; 64 } else 65 return __earlyonly_bootmem_alloc(node, size, size, 66 __pa(MAX_DMA_ADDRESS)); 67 } 68 69 /* need to make sure size is all the same during early stage */ 70 static void * __meminit alloc_block_buf(unsigned long size, int node) 71 { 72 void *ptr; 73 74 if (!vmemmap_buf) 75 return vmemmap_alloc_block(size, node); 76 77 /* take the from buf */ 78 ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); 79 if (ptr + size > vmemmap_buf_end) 80 return vmemmap_alloc_block(size, node); 81 82 vmemmap_buf = ptr + size; 83 84 return ptr; 85 } 86 87 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) 88 { 89 return altmap->base_pfn + altmap->reserve + altmap->alloc 90 + altmap->align; 91 } 92 93 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) 94 { 95 unsigned long allocated = altmap->alloc + altmap->align; 96 97 if (altmap->free > allocated) 98 return altmap->free - allocated; 99 return 0; 100 } 101 102 /** 103 * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation 104 * @altmap - reserved page pool for the allocation 105 * @nr_pfns - size (in pages) of the allocation 106 * 107 * Allocations are aligned to the size of the request 108 */ 109 static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap, 110 unsigned long nr_pfns) 111 { 112 unsigned long pfn = vmem_altmap_next_pfn(altmap); 113 unsigned long nr_align; 114 115 nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); 116 nr_align = ALIGN(pfn, nr_align) - pfn; 117 118 if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) 119 return ULONG_MAX; 120 altmap->alloc += nr_pfns; 121 altmap->align += nr_align; 122 return pfn + nr_align; 123 } 124 125 static void * __meminit altmap_alloc_block_buf(unsigned long size, 126 struct vmem_altmap *altmap) 127 { 128 unsigned long pfn, nr_pfns; 129 void *ptr; 130 131 if (size & ~PAGE_MASK) { 132 pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", 133 __func__, size); 134 return NULL; 135 } 136 137 nr_pfns = size >> PAGE_SHIFT; 138 pfn = vmem_altmap_alloc(altmap, nr_pfns); 139 if (pfn < ULONG_MAX) 140 ptr = __va(__pfn_to_phys(pfn)); 141 else 142 ptr = NULL; 143 pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", 144 __func__, pfn, altmap->alloc, altmap->align, nr_pfns); 145 146 return ptr; 147 } 148 149 /* need to make sure size is all the same during early stage */ 150 void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node, 151 struct vmem_altmap *altmap) 152 { 153 if (altmap) 154 return altmap_alloc_block_buf(size, altmap); 155 return alloc_block_buf(size, node); 156 } 157 158 void __meminit vmemmap_verify(pte_t *pte, int node, 159 unsigned long start, unsigned long end) 160 { 161 unsigned long pfn = pte_pfn(*pte); 162 int actual_node = early_pfn_to_nid(pfn); 163 164 if (node_distance(actual_node, node) > LOCAL_DISTANCE) 165 pr_warn("[%lx-%lx] potential offnode page_structs\n", 166 start, end - 1); 167 } 168 169 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) 170 { 171 pte_t *pte = pte_offset_kernel(pmd, addr); 172 if (pte_none(*pte)) { 173 pte_t entry; 174 void *p = alloc_block_buf(PAGE_SIZE, node); 175 if (!p) 176 return NULL; 177 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); 178 set_pte_at(&init_mm, addr, pte, entry); 179 } 180 return pte; 181 } 182 183 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) 184 { 185 pmd_t *pmd = pmd_offset(pud, addr); 186 if (pmd_none(*pmd)) { 187 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 188 if (!p) 189 return NULL; 190 pmd_populate_kernel(&init_mm, pmd, p); 191 } 192 return pmd; 193 } 194 195 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) 196 { 197 pud_t *pud = pud_offset(p4d, addr); 198 if (pud_none(*pud)) { 199 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 200 if (!p) 201 return NULL; 202 pud_populate(&init_mm, pud, p); 203 } 204 return pud; 205 } 206 207 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) 208 { 209 p4d_t *p4d = p4d_offset(pgd, addr); 210 if (p4d_none(*p4d)) { 211 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 212 if (!p) 213 return NULL; 214 p4d_populate(&init_mm, p4d, p); 215 } 216 return p4d; 217 } 218 219 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 220 { 221 pgd_t *pgd = pgd_offset_k(addr); 222 if (pgd_none(*pgd)) { 223 void *p = vmemmap_alloc_block(PAGE_SIZE, node); 224 if (!p) 225 return NULL; 226 pgd_populate(&init_mm, pgd, p); 227 } 228 return pgd; 229 } 230 231 int __meminit vmemmap_populate_basepages(unsigned long start, 232 unsigned long end, int node) 233 { 234 unsigned long addr = start; 235 pgd_t *pgd; 236 p4d_t *p4d; 237 pud_t *pud; 238 pmd_t *pmd; 239 pte_t *pte; 240 241 for (; addr < end; addr += PAGE_SIZE) { 242 pgd = vmemmap_pgd_populate(addr, node); 243 if (!pgd) 244 return -ENOMEM; 245 p4d = vmemmap_p4d_populate(pgd, addr, node); 246 if (!p4d) 247 return -ENOMEM; 248 pud = vmemmap_pud_populate(p4d, addr, node); 249 if (!pud) 250 return -ENOMEM; 251 pmd = vmemmap_pmd_populate(pud, addr, node); 252 if (!pmd) 253 return -ENOMEM; 254 pte = vmemmap_pte_populate(pmd, addr, node); 255 if (!pte) 256 return -ENOMEM; 257 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 258 } 259 260 return 0; 261 } 262 263 struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid) 264 { 265 unsigned long start; 266 unsigned long end; 267 struct page *map; 268 269 map = pfn_to_page(pnum * PAGES_PER_SECTION); 270 start = (unsigned long)map; 271 end = (unsigned long)(map + PAGES_PER_SECTION); 272 273 if (vmemmap_populate(start, end, nid)) 274 return NULL; 275 276 return map; 277 } 278 279 void __init sparse_mem_maps_populate_node(struct page **map_map, 280 unsigned long pnum_begin, 281 unsigned long pnum_end, 282 unsigned long map_count, int nodeid) 283 { 284 unsigned long pnum; 285 unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; 286 void *vmemmap_buf_start; 287 288 size = ALIGN(size, PMD_SIZE); 289 vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, 290 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 291 292 if (vmemmap_buf_start) { 293 vmemmap_buf = vmemmap_buf_start; 294 vmemmap_buf_end = vmemmap_buf_start + size * map_count; 295 } 296 297 for (pnum = pnum_begin; pnum < pnum_end; pnum++) { 298 struct mem_section *ms; 299 300 if (!present_section_nr(pnum)) 301 continue; 302 303 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid); 304 if (map_map[pnum]) 305 continue; 306 ms = __nr_to_section(pnum); 307 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", 308 __func__); 309 ms->section_mem_map = 0; 310 } 311 312 if (vmemmap_buf_start) { 313 /* need to free left buf */ 314 memblock_free_early(__pa(vmemmap_buf), 315 vmemmap_buf_end - vmemmap_buf); 316 vmemmap_buf = NULL; 317 vmemmap_buf_end = NULL; 318 } 319 } 320