1 /* 2 * mm/pgtable-generic.c 3 * 4 * Generic pgtable methods declared in asm-generic/pgtable.h 5 * 6 * Copyright (C) 2010 Linus Torvalds 7 */ 8 9 #include <linux/pagemap.h> 10 #include <asm/tlb.h> 11 #include <asm-generic/pgtable.h> 12 13 /* 14 * If a p?d_bad entry is found while walking page tables, report 15 * the error, before resetting entry to p?d_none. Usually (but 16 * very seldom) called out from the p?d_none_or_clear_bad macros. 17 */ 18 19 void pgd_clear_bad(pgd_t *pgd) 20 { 21 pgd_ERROR(*pgd); 22 pgd_clear(pgd); 23 } 24 25 void pud_clear_bad(pud_t *pud) 26 { 27 pud_ERROR(*pud); 28 pud_clear(pud); 29 } 30 31 void pmd_clear_bad(pmd_t *pmd) 32 { 33 pmd_ERROR(*pmd); 34 pmd_clear(pmd); 35 } 36 37 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS 38 /* 39 * Only sets the access flags (dirty, accessed), as well as write 40 * permission. Furthermore, we know it always gets set to a "more 41 * permissive" setting, which allows most architectures to optimize 42 * this. We return whether the PTE actually changed, which in turn 43 * instructs the caller to do things like update__mmu_cache. This 44 * used to be done in the caller, but sparc needs minor faults to 45 * force that call on sun4c so we changed this macro slightly 46 */ 47 int ptep_set_access_flags(struct vm_area_struct *vma, 48 unsigned long address, pte_t *ptep, 49 pte_t entry, int dirty) 50 { 51 int changed = !pte_same(*ptep, entry); 52 if (changed) { 53 set_pte_at(vma->vm_mm, address, ptep, entry); 54 flush_tlb_fix_spurious_fault(vma, address); 55 } 56 return changed; 57 } 58 #endif 59 60 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH 61 int ptep_clear_flush_young(struct vm_area_struct *vma, 62 unsigned long address, pte_t *ptep) 63 { 64 int young; 65 young = ptep_test_and_clear_young(vma, address, ptep); 66 if (young) 67 flush_tlb_page(vma, address); 68 return young; 69 } 70 #endif 71 72 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH 73 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, 74 pte_t *ptep) 75 { 76 struct mm_struct *mm = (vma)->vm_mm; 77 pte_t pte; 78 pte = ptep_get_and_clear(mm, address, ptep); 79 if (pte_accessible(mm, pte)) 80 flush_tlb_page(vma, address); 81 return pte; 82 } 83 #endif 84 85 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 86 87 #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE 88 89 /* 90 * ARCHes with special requirements for evicting THP backing TLB entries can 91 * implement this. Otherwise also, it can help optimize normal TLB flush in 92 * THP regime. stock flush_tlb_range() typically has optimization to nuke the 93 * entire TLB TLB if flush span is greater than a threshhold, which will 94 * likely be true for a single huge page. Thus a single thp flush will 95 * invalidate the entire TLB which is not desitable. 96 * e.g. see arch/arc: flush_pmd_tlb_range 97 */ 98 #define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) 99 #endif 100 101 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS 102 int pmdp_set_access_flags(struct vm_area_struct *vma, 103 unsigned long address, pmd_t *pmdp, 104 pmd_t entry, int dirty) 105 { 106 int changed = !pmd_same(*pmdp, entry); 107 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 108 if (changed) { 109 set_pmd_at(vma->vm_mm, address, pmdp, entry); 110 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 111 } 112 return changed; 113 } 114 #endif 115 116 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH 117 int pmdp_clear_flush_young(struct vm_area_struct *vma, 118 unsigned long address, pmd_t *pmdp) 119 { 120 int young; 121 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 122 young = pmdp_test_and_clear_young(vma, address, pmdp); 123 if (young) 124 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 125 return young; 126 } 127 #endif 128 129 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH 130 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address, 131 pmd_t *pmdp) 132 { 133 pmd_t pmd; 134 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 135 VM_BUG_ON(!pmd_trans_huge(*pmdp)); 136 pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp); 137 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 138 return pmd; 139 } 140 #endif 141 142 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH 143 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, 144 pmd_t *pmdp) 145 { 146 pmd_t pmd = pmd_mksplitting(*pmdp); 147 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 148 set_pmd_at(vma->vm_mm, address, pmdp, pmd); 149 /* tlb flush only to serialize against gup-fast */ 150 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 151 } 152 #endif 153 154 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT 155 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 156 pgtable_t pgtable) 157 { 158 assert_spin_locked(pmd_lockptr(mm, pmdp)); 159 160 /* FIFO */ 161 if (!pmd_huge_pte(mm, pmdp)) 162 INIT_LIST_HEAD(&pgtable->lru); 163 else 164 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru); 165 pmd_huge_pte(mm, pmdp) = pgtable; 166 } 167 #endif 168 169 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW 170 /* no "address" argument so destroys page coloring of some arch */ 171 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 172 { 173 pgtable_t pgtable; 174 175 assert_spin_locked(pmd_lockptr(mm, pmdp)); 176 177 /* FIFO */ 178 pgtable = pmd_huge_pte(mm, pmdp); 179 if (list_empty(&pgtable->lru)) 180 pmd_huge_pte(mm, pmdp) = NULL; 181 else { 182 pmd_huge_pte(mm, pmdp) = list_entry(pgtable->lru.next, 183 struct page, lru); 184 list_del(&pgtable->lru); 185 } 186 return pgtable; 187 } 188 #endif 189 190 #ifndef __HAVE_ARCH_PMDP_INVALIDATE 191 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 192 pmd_t *pmdp) 193 { 194 pmd_t entry = *pmdp; 195 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry)); 196 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 197 } 198 #endif 199 200 #ifndef pmdp_collapse_flush 201 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address, 202 pmd_t *pmdp) 203 { 204 /* 205 * pmd and hugepage pte format are same. So we could 206 * use the same function. 207 */ 208 pmd_t pmd; 209 210 VM_BUG_ON(address & ~HPAGE_PMD_MASK); 211 VM_BUG_ON(pmd_trans_huge(*pmdp)); 212 pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp); 213 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 214 return pmd; 215 } 216 #endif 217 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 218