1 #include <linux/mm.h> 2 #include <linux/highmem.h> 3 #include <linux/sched.h> 4 5 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 6 const struct mm_walk *walk, void *private) 7 { 8 pte_t *pte; 9 int err = 0; 10 11 pte = pte_offset_map(pmd, addr); 12 do { 13 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, private); 14 if (err) 15 break; 16 } while (pte++, addr += PAGE_SIZE, addr != end); 17 18 pte_unmap(pte); 19 return err; 20 } 21 22 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, 23 const struct mm_walk *walk, void *private) 24 { 25 pmd_t *pmd; 26 unsigned long next; 27 int err = 0; 28 29 pmd = pmd_offset(pud, addr); 30 do { 31 next = pmd_addr_end(addr, end); 32 if (pmd_none_or_clear_bad(pmd)) { 33 if (walk->pte_hole) 34 err = walk->pte_hole(addr, next, private); 35 if (err) 36 break; 37 continue; 38 } 39 if (walk->pmd_entry) 40 err = walk->pmd_entry(pmd, addr, next, private); 41 if (!err && walk->pte_entry) 42 err = walk_pte_range(pmd, addr, next, walk, private); 43 if (err) 44 break; 45 } while (pmd++, addr = next, addr != end); 46 47 return err; 48 } 49 50 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, 51 const struct mm_walk *walk, void *private) 52 { 53 pud_t *pud; 54 unsigned long next; 55 int err = 0; 56 57 pud = pud_offset(pgd, addr); 58 do { 59 next = pud_addr_end(addr, end); 60 if (pud_none_or_clear_bad(pud)) { 61 if (walk->pte_hole) 62 err = walk->pte_hole(addr, next, private); 63 if (err) 64 break; 65 continue; 66 } 67 if (walk->pud_entry) 68 err = walk->pud_entry(pud, addr, next, private); 69 if (!err && (walk->pmd_entry || walk->pte_entry)) 70 err = walk_pmd_range(pud, addr, next, walk, private); 71 if (err) 72 break; 73 } while (pud++, addr = next, addr != end); 74 75 return err; 76 } 77 78 /** 79 * walk_page_range - walk a memory map's page tables with a callback 80 * @mm: memory map to walk 81 * @addr: starting address 82 * @end: ending address 83 * @walk: set of callbacks to invoke for each level of the tree 84 * @private: private data passed to the callback function 85 * 86 * Recursively walk the page table for the memory area in a VMA, 87 * calling supplied callbacks. Callbacks are called in-order (first 88 * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, 89 * etc.). If lower-level callbacks are omitted, walking depth is reduced. 90 * 91 * Each callback receives an entry pointer, the start and end of the 92 * associated range, and a caller-supplied private data pointer. 93 * 94 * No locks are taken, but the bottom level iterator will map PTE 95 * directories from highmem if necessary. 96 * 97 * If any callback returns a non-zero value, the walk is aborted and 98 * the return value is propagated back to the caller. Otherwise 0 is returned. 99 */ 100 int walk_page_range(const struct mm_struct *mm, 101 unsigned long addr, unsigned long end, 102 const struct mm_walk *walk, void *private) 103 { 104 pgd_t *pgd; 105 unsigned long next; 106 int err = 0; 107 108 if (addr >= end) 109 return err; 110 111 pgd = pgd_offset(mm, addr); 112 do { 113 next = pgd_addr_end(addr, end); 114 if (pgd_none_or_clear_bad(pgd)) { 115 if (walk->pte_hole) 116 err = walk->pte_hole(addr, next, private); 117 if (err) 118 break; 119 continue; 120 } 121 if (walk->pgd_entry) 122 err = walk->pgd_entry(pgd, addr, next, private); 123 if (!err && 124 (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) 125 err = walk_pud_range(pgd, addr, next, walk, private); 126 if (err) 127 break; 128 } while (pgd++, addr = next, addr != end); 129 130 return err; 131 } 132