1 #include <linux/mm.h> 2 #include <linux/highmem.h> 3 #include <linux/sched.h> 4 #include <linux/hugetlb.h> 5 6 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 7 struct mm_walk *walk) 8 { 9 pte_t *pte; 10 int err = 0; 11 12 pte = pte_offset_map(pmd, addr); 13 for (;;) { 14 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk); 15 if (err) 16 break; 17 addr += PAGE_SIZE; 18 if (addr == end) 19 break; 20 pte++; 21 } 22 23 pte_unmap(pte); 24 return err; 25 } 26 27 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, 28 struct mm_walk *walk) 29 { 30 pmd_t *pmd; 31 unsigned long next; 32 int err = 0; 33 34 pmd = pmd_offset(pud, addr); 35 do { 36 again: 37 next = pmd_addr_end(addr, end); 38 if (pmd_none(*pmd)) { 39 if (walk->pte_hole) 40 err = walk->pte_hole(addr, next, walk); 41 if (err) 42 break; 43 continue; 44 } 45 /* 46 * This implies that each ->pmd_entry() handler 47 * needs to know about pmd_trans_huge() pmds 48 */ 49 if (walk->pmd_entry) 50 err = walk->pmd_entry(pmd, addr, next, walk); 51 if (err) 52 break; 53 54 /* 55 * Check this here so we only break down trans_huge 56 * pages when we _need_ to 57 */ 58 if (!walk->pte_entry) 59 continue; 60 61 split_huge_page_pmd(walk->mm, pmd); 62 if (pmd_none_or_clear_bad(pmd)) 63 goto again; 64 err = walk_pte_range(pmd, addr, next, walk); 65 if (err) 66 break; 67 } while (pmd++, addr = next, addr != end); 68 69 return err; 70 } 71 72 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, 73 struct mm_walk *walk) 74 { 75 pud_t *pud; 76 unsigned long next; 77 int err = 0; 78 79 pud = pud_offset(pgd, addr); 80 do { 81 next = pud_addr_end(addr, end); 82 if (pud_none_or_clear_bad(pud)) { 83 if (walk->pte_hole) 84 err = walk->pte_hole(addr, next, walk); 85 if (err) 86 break; 87 continue; 88 } 89 if (walk->pud_entry) 90 err = walk->pud_entry(pud, addr, next, walk); 91 if (!err && (walk->pmd_entry || walk->pte_entry)) 92 err = walk_pmd_range(pud, addr, next, walk); 93 if (err) 94 break; 95 } while (pud++, addr = next, addr != end); 96 97 return err; 98 } 99 100 #ifdef CONFIG_HUGETLB_PAGE 101 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr, 102 unsigned long end) 103 { 104 unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h); 105 return boundary < end ? boundary : end; 106 } 107 108 static int walk_hugetlb_range(struct vm_area_struct *vma, 109 unsigned long addr, unsigned long end, 110 struct mm_walk *walk) 111 { 112 struct hstate *h = hstate_vma(vma); 113 unsigned long next; 114 unsigned long hmask = huge_page_mask(h); 115 pte_t *pte; 116 int err = 0; 117 118 do { 119 next = hugetlb_entry_end(h, addr, end); 120 pte = huge_pte_offset(walk->mm, addr & hmask); 121 if (pte && walk->hugetlb_entry) 122 err = walk->hugetlb_entry(pte, hmask, addr, next, walk); 123 if (err) 124 return err; 125 } while (addr = next, addr != end); 126 127 return 0; 128 } 129 #endif 130 131 /** 132 * walk_page_range - walk a memory map's page tables with a callback 133 * @mm: memory map to walk 134 * @addr: starting address 135 * @end: ending address 136 * @walk: set of callbacks to invoke for each level of the tree 137 * 138 * Recursively walk the page table for the memory area in a VMA, 139 * calling supplied callbacks. Callbacks are called in-order (first 140 * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, 141 * etc.). If lower-level callbacks are omitted, walking depth is reduced. 142 * 143 * Each callback receives an entry pointer and the start and end of the 144 * associated range, and a copy of the original mm_walk for access to 145 * the ->private or ->mm fields. 146 * 147 * No locks are taken, but the bottom level iterator will map PTE 148 * directories from highmem if necessary. 149 * 150 * If any callback returns a non-zero value, the walk is aborted and 151 * the return value is propagated back to the caller. Otherwise 0 is returned. 152 */ 153 int walk_page_range(unsigned long addr, unsigned long end, 154 struct mm_walk *walk) 155 { 156 pgd_t *pgd; 157 unsigned long next; 158 int err = 0; 159 160 if (addr >= end) 161 return err; 162 163 if (!walk->mm) 164 return -EINVAL; 165 166 pgd = pgd_offset(walk->mm, addr); 167 do { 168 struct vm_area_struct *uninitialized_var(vma); 169 170 next = pgd_addr_end(addr, end); 171 172 #ifdef CONFIG_HUGETLB_PAGE 173 /* 174 * handle hugetlb vma individually because pagetable walk for 175 * the hugetlb page is dependent on the architecture and 176 * we can't handled it in the same manner as non-huge pages. 177 */ 178 vma = find_vma(walk->mm, addr); 179 if (vma && is_vm_hugetlb_page(vma)) { 180 if (vma->vm_end < next) 181 next = vma->vm_end; 182 /* 183 * Hugepage is very tightly coupled with vma, so 184 * walk through hugetlb entries within a given vma. 185 */ 186 err = walk_hugetlb_range(vma, addr, next, walk); 187 if (err) 188 break; 189 pgd = pgd_offset(walk->mm, next); 190 continue; 191 } 192 #endif 193 if (pgd_none_or_clear_bad(pgd)) { 194 if (walk->pte_hole) 195 err = walk->pte_hole(addr, next, walk); 196 if (err) 197 break; 198 pgd++; 199 continue; 200 } 201 if (walk->pgd_entry) 202 err = walk->pgd_entry(pgd, addr, next, walk); 203 if (!err && 204 (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) 205 err = walk_pud_range(pgd, addr, next, walk); 206 if (err) 207 break; 208 pgd++; 209 } while (addr = next, addr != end); 210 211 return err; 212 } 213