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 33 /* 34 * Allocate a block of memory to be used to back the virtual memory map 35 * or to back the page tables that are used to create the mapping. 36 * Uses the main allocators if they are available, else bootmem. 37 */ 38 39 static void * __ref __earlyonly_bootmem_alloc(int node, 40 unsigned long size, 41 unsigned long align, 42 unsigned long goal) 43 { 44 return memblock_alloc_try_nid_raw(size, align, goal, 45 MEMBLOCK_ALLOC_ACCESSIBLE, node); 46 } 47 48 void * __meminit vmemmap_alloc_block(unsigned long size, int node) 49 { 50 /* If the main allocator is up use that, fallback to bootmem. */ 51 if (slab_is_available()) { 52 gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; 53 int order = get_order(size); 54 static bool warned; 55 struct page *page; 56 57 page = alloc_pages_node(node, gfp_mask, order); 58 if (page) 59 return page_address(page); 60 61 if (!warned) { 62 warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, 63 "vmemmap alloc failure: order:%u", order); 64 warned = true; 65 } 66 return NULL; 67 } else 68 return __earlyonly_bootmem_alloc(node, size, size, 69 __pa(MAX_DMA_ADDRESS)); 70 } 71 72 static void * __meminit altmap_alloc_block_buf(unsigned long size, 73 struct vmem_altmap *altmap); 74 75 /* need to make sure size is all the same during early stage */ 76 void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node, 77 struct vmem_altmap *altmap) 78 { 79 void *ptr; 80 81 if (altmap) 82 return altmap_alloc_block_buf(size, altmap); 83 84 ptr = sparse_buffer_alloc(size); 85 if (!ptr) 86 ptr = vmemmap_alloc_block(size, node); 87 return ptr; 88 } 89 90 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) 91 { 92 return altmap->base_pfn + altmap->reserve + altmap->alloc 93 + altmap->align; 94 } 95 96 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) 97 { 98 unsigned long allocated = altmap->alloc + altmap->align; 99 100 if (altmap->free > allocated) 101 return altmap->free - allocated; 102 return 0; 103 } 104 105 static 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 struct vmem_altmap *altmap) 145 { 146 pte_t *pte = pte_offset_kernel(pmd, addr); 147 if (pte_none(*pte)) { 148 pte_t entry; 149 void *p; 150 151 p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap); 152 if (!p) 153 return NULL; 154 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); 155 set_pte_at(&init_mm, addr, pte, entry); 156 } 157 return pte; 158 } 159 160 static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) 161 { 162 void *p = vmemmap_alloc_block(size, node); 163 164 if (!p) 165 return NULL; 166 memset(p, 0, size); 167 168 return p; 169 } 170 171 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) 172 { 173 pmd_t *pmd = pmd_offset(pud, addr); 174 if (pmd_none(*pmd)) { 175 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 176 if (!p) 177 return NULL; 178 pmd_populate_kernel(&init_mm, pmd, p); 179 } 180 return pmd; 181 } 182 183 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) 184 { 185 pud_t *pud = pud_offset(p4d, addr); 186 if (pud_none(*pud)) { 187 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 188 if (!p) 189 return NULL; 190 pud_populate(&init_mm, pud, p); 191 } 192 return pud; 193 } 194 195 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) 196 { 197 p4d_t *p4d = p4d_offset(pgd, addr); 198 if (p4d_none(*p4d)) { 199 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 200 if (!p) 201 return NULL; 202 p4d_populate(&init_mm, p4d, p); 203 } 204 return p4d; 205 } 206 207 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) 208 { 209 pgd_t *pgd = pgd_offset_k(addr); 210 if (pgd_none(*pgd)) { 211 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); 212 if (!p) 213 return NULL; 214 pgd_populate(&init_mm, pgd, p); 215 } 216 return pgd; 217 } 218 219 int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end, 220 int node, struct vmem_altmap *altmap) 221 { 222 unsigned long addr = start; 223 pgd_t *pgd; 224 p4d_t *p4d; 225 pud_t *pud; 226 pmd_t *pmd; 227 pte_t *pte; 228 229 for (; addr < end; addr += PAGE_SIZE) { 230 pgd = vmemmap_pgd_populate(addr, node); 231 if (!pgd) 232 return -ENOMEM; 233 p4d = vmemmap_p4d_populate(pgd, addr, node); 234 if (!p4d) 235 return -ENOMEM; 236 pud = vmemmap_pud_populate(p4d, addr, node); 237 if (!pud) 238 return -ENOMEM; 239 pmd = vmemmap_pmd_populate(pud, addr, node); 240 if (!pmd) 241 return -ENOMEM; 242 pte = vmemmap_pte_populate(pmd, addr, node, altmap); 243 if (!pte) 244 return -ENOMEM; 245 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 246 } 247 248 return 0; 249 } 250 251 struct page * __meminit __populate_section_memmap(unsigned long pfn, 252 unsigned long nr_pages, int nid, struct vmem_altmap *altmap) 253 { 254 unsigned long start = (unsigned long) pfn_to_page(pfn); 255 unsigned long end = start + nr_pages * sizeof(struct page); 256 257 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) || 258 !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) 259 return NULL; 260 261 if (vmemmap_populate(start, end, nid, altmap)) 262 return NULL; 263 264 return pfn_to_page(pfn); 265 } 266