| 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 | } |