| 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/memblock.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_alloc_try_nid_raw(size, align, goal, |
| 46 | MEMBLOCK_ALLOC_ACCESSIBLE, node); |
| 47 | } |
| 48 | |
| 49 | void * __meminit vmemmap_alloc_block(unsigned long size, int node) |
| 50 | { |
| 51 | /* If the main allocator is up use that, fallback to bootmem. */ |
| 52 | if (slab_is_available()) { |
| 53 | gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; |
| 54 | int order = get_order(size); |
| 55 | static bool warned; |
| 56 | struct page *page; |
| 57 | |
| 58 | page = alloc_pages_node(node, gfp_mask, order); |
| 59 | if (page) |
| 60 | return page_address(page); |
| 61 | |
| 62 | if (!warned) { |
| 63 | warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, |
| 64 | "vmemmap alloc failure: order:%u", order); |
| 65 | warned = true; |
| 66 | } |
| 67 | return NULL; |
| 68 | } else |
| 69 | return __earlyonly_bootmem_alloc(node, size, size, |
| 70 | __pa(MAX_DMA_ADDRESS)); |
| 71 | } |
| 72 | |
| 73 | /* need to make sure size is all the same during early stage */ |
| 74 | void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) |
| 75 | { |
| 76 | void *ptr = sparse_buffer_alloc(size); |
| 77 | |
| 78 | if (!ptr) |
| 79 | ptr = vmemmap_alloc_block(size, node); |
| 80 | return ptr; |
| 81 | } |
| 82 | |
| 83 | static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) |
| 84 | { |
| 85 | return altmap->base_pfn + altmap->reserve + altmap->alloc |
| 86 | + altmap->align; |
| 87 | } |
| 88 | |
| 89 | static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) |
| 90 | { |
| 91 | unsigned long allocated = altmap->alloc + altmap->align; |
| 92 | |
| 93 | if (altmap->free > allocated) |
| 94 | return altmap->free - allocated; |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * altmap_alloc_block_buf - allocate pages from the device page map |
| 100 | * @altmap: device page map |
| 101 | * @size: size (in bytes) of the allocation |
| 102 | * |
| 103 | * Allocations are aligned to the size of the request. |
| 104 | */ |
| 105 | void * __meminit altmap_alloc_block_buf(unsigned long size, |
| 106 | struct vmem_altmap *altmap) |
| 107 | { |
| 108 | unsigned long pfn, nr_pfns, nr_align; |
| 109 | |
| 110 | if (size & ~PAGE_MASK) { |
| 111 | pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", |
| 112 | __func__, size); |
| 113 | return NULL; |
| 114 | } |
| 115 | |
| 116 | pfn = vmem_altmap_next_pfn(altmap); |
| 117 | nr_pfns = size >> PAGE_SHIFT; |
| 118 | nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); |
| 119 | nr_align = ALIGN(pfn, nr_align) - pfn; |
| 120 | if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) |
| 121 | return NULL; |
| 122 | |
| 123 | altmap->alloc += nr_pfns; |
| 124 | altmap->align += nr_align; |
| 125 | pfn += nr_align; |
| 126 | |
| 127 | pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", |
| 128 | __func__, pfn, altmap->alloc, altmap->align, nr_pfns); |
| 129 | return __va(__pfn_to_phys(pfn)); |
| 130 | } |
| 131 | |
| 132 | void __meminit vmemmap_verify(pte_t *pte, int node, |
| 133 | unsigned long start, unsigned long end) |
| 134 | { |
| 135 | unsigned long pfn = pte_pfn(*pte); |
| 136 | int actual_node = early_pfn_to_nid(pfn); |
| 137 | |
| 138 | if (node_distance(actual_node, node) > LOCAL_DISTANCE) |
| 139 | pr_warn("[%lx-%lx] potential offnode page_structs\n", |
| 140 | start, end - 1); |
| 141 | } |
| 142 | |
| 143 | pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) |
| 144 | { |
| 145 | pte_t *pte = pte_offset_kernel(pmd, addr); |
| 146 | if (pte_none(*pte)) { |
| 147 | pte_t entry; |
| 148 | void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); |
| 149 | if (!p) |
| 150 | return NULL; |
| 151 | entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); |
| 152 | set_pte_at(&init_mm, addr, pte, entry); |
| 153 | } |
| 154 | return pte; |
| 155 | } |
| 156 | |
| 157 | static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) |
| 158 | { |
| 159 | void *p = vmemmap_alloc_block(size, node); |
| 160 | |
| 161 | if (!p) |
| 162 | return NULL; |
| 163 | memset(p, 0, size); |
| 164 | |
| 165 | return p; |
| 166 | } |
| 167 | |
| 168 | pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) |
| 169 | { |
| 170 | pmd_t *pmd = pmd_offset(pud, addr); |
| 171 | if (pmd_none(*pmd)) { |
| 172 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
| 173 | if (!p) |
| 174 | return NULL; |
| 175 | pmd_populate_kernel(&init_mm, pmd, p); |
| 176 | } |
| 177 | return pmd; |
| 178 | } |
| 179 | |
| 180 | pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) |
| 181 | { |
| 182 | pud_t *pud = pud_offset(p4d, addr); |
| 183 | if (pud_none(*pud)) { |
| 184 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
| 185 | if (!p) |
| 186 | return NULL; |
| 187 | pud_populate(&init_mm, pud, p); |
| 188 | } |
| 189 | return pud; |
| 190 | } |
| 191 | |
| 192 | p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) |
| 193 | { |
| 194 | p4d_t *p4d = p4d_offset(pgd, addr); |
| 195 | if (p4d_none(*p4d)) { |
| 196 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
| 197 | if (!p) |
| 198 | return NULL; |
| 199 | p4d_populate(&init_mm, p4d, p); |
| 200 | } |
| 201 | return p4d; |
| 202 | } |
| 203 | |
| 204 | pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) |
| 205 | { |
| 206 | pgd_t *pgd = pgd_offset_k(addr); |
| 207 | if (pgd_none(*pgd)) { |
| 208 | void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
| 209 | if (!p) |
| 210 | return NULL; |
| 211 | pgd_populate(&init_mm, pgd, p); |
| 212 | } |
| 213 | return pgd; |
| 214 | } |
| 215 | |
| 216 | int __meminit vmemmap_populate_basepages(unsigned long start, |
| 217 | unsigned long end, int node) |
| 218 | { |
| 219 | unsigned long addr = start; |
| 220 | pgd_t *pgd; |
| 221 | p4d_t *p4d; |
| 222 | pud_t *pud; |
| 223 | pmd_t *pmd; |
| 224 | pte_t *pte; |
| 225 | |
| 226 | for (; addr < end; addr += PAGE_SIZE) { |
| 227 | pgd = vmemmap_pgd_populate(addr, node); |
| 228 | if (!pgd) |
| 229 | return -ENOMEM; |
| 230 | p4d = vmemmap_p4d_populate(pgd, addr, node); |
| 231 | if (!p4d) |
| 232 | return -ENOMEM; |
| 233 | pud = vmemmap_pud_populate(p4d, addr, node); |
| 234 | if (!pud) |
| 235 | return -ENOMEM; |
| 236 | pmd = vmemmap_pmd_populate(pud, addr, node); |
| 237 | if (!pmd) |
| 238 | return -ENOMEM; |
| 239 | pte = vmemmap_pte_populate(pmd, addr, node); |
| 240 | if (!pte) |
| 241 | return -ENOMEM; |
| 242 | vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); |
| 243 | } |
| 244 | |
| 245 | return 0; |
| 246 | } |
| 247 | |
| 248 | struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid, |
| 249 | struct vmem_altmap *altmap) |
| 250 | { |
| 251 | unsigned long start; |
| 252 | unsigned long end; |
| 253 | struct page *map; |
| 254 | |
| 255 | map = pfn_to_page(pnum * PAGES_PER_SECTION); |
| 256 | start = (unsigned long)map; |
| 257 | end = (unsigned long)(map + PAGES_PER_SECTION); |
| 258 | |
| 259 | if (vmemmap_populate(start, end, nid, altmap)) |
| 260 | return NULL; |
| 261 | |
| 262 | return map; |
| 263 | } |