the-tree/mm/pgtable-generic.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  *  mm/pgtable-generic.c
0004  *
0005  *  Generic pgtable methods declared in linux/pgtable.h
0006  *
0007  *  Copyright (C) 2010  Linus Torvalds
0008  */
0009
0010 #include <linux/pagemap.h>
0011 #include <linux/hugetlb.h>
0012 #include <linux/pgtable.h>
0013 #include <linux/mm_inline.h>
0014 #include <asm/tlb.h>
0015
0016 /*
0017  * If a p?d_bad entry is found while walking page tables, report
0018  * the error, before resetting entry to p?d_none.  Usually (but
0019  * very seldom) called out from the p?d_none_or_clear_bad macros.
0020  */
0021
0022 void pgd_clear_bad(pgd_t *pgd)
0023 {
0024     pgd_ERROR(*pgd);
0025     pgd_clear(pgd);
0026 }
0027
0028 #ifndef __PAGETABLE_P4D_FOLDED
0029 void p4d_clear_bad(p4d_t *p4d)
0030 {
0031     p4d_ERROR(*p4d);
0032     p4d_clear(p4d);
0033 }
0034 #endif
0035
0036 #ifndef __PAGETABLE_PUD_FOLDED
0037 void pud_clear_bad(pud_t *pud)
0038 {
0039     pud_ERROR(*pud);
0040     pud_clear(pud);
0041 }
0042 #endif
0043
0044 /*
0045  * Note that the pmd variant below can't be stub'ed out just as for p4d/pud
0046  * above. pmd folding is special and typically pmd_* macros refer to upper
0047  * level even when folded
0048  */
0049 void pmd_clear_bad(pmd_t *pmd)
0050 {
0051     pmd_ERROR(*pmd);
0052     pmd_clear(pmd);
0053 }
0054
0055 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
0056 /*
0057  * Only sets the access flags (dirty, accessed), as well as write
0058  * permission. Furthermore, we know it always gets set to a "more
0059  * permissive" setting, which allows most architectures to optimize
0060  * this. We return whether the PTE actually changed, which in turn
0061  * instructs the caller to do things like update__mmu_cache.  This
0062  * used to be done in the caller, but sparc needs minor faults to
0063  * force that call on sun4c so we changed this macro slightly
0064  */
0065 int ptep_set_access_flags(struct vm_area_struct *vma,
0066               unsigned long address, pte_t *ptep,
0067               pte_t entry, int dirty)
0068 {
0069     int changed = !pte_same(*ptep, entry);
0070     if (changed) {
0071         set_pte_at(vma->vm_mm, address, ptep, entry);
0072         flush_tlb_fix_spurious_fault(vma, address);
0073     }
0074     return changed;
0075 }
0076 #endif
0077
0078 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
0079 int ptep_clear_flush_young(struct vm_area_struct *vma,
0080                unsigned long address, pte_t *ptep)
0081 {
0082     int young;
0083     young = ptep_test_and_clear_young(vma, address, ptep);
0084     if (young)
0085         flush_tlb_page(vma, address);
0086     return young;
0087 }
0088 #endif
0089
0090 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
0091 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
0092                pte_t *ptep)
0093 {
0094     struct mm_struct *mm = (vma)->vm_mm;
0095     pte_t pte;
0096     pte = ptep_get_and_clear(mm, address, ptep);
0097     if (pte_accessible(mm, pte))
0098         flush_tlb_page(vma, address);
0099     return pte;
0100 }
0101 #endif
0102
0103 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
0104
0105 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
0106 int pmdp_set_access_flags(struct vm_area_struct *vma,
0107               unsigned long address, pmd_t *pmdp,
0108               pmd_t entry, int dirty)
0109 {
0110     int changed = !pmd_same(*pmdp, entry);
0111     VM_BUG_ON(address & ~HPAGE_PMD_MASK);
0112     if (changed) {
0113         set_pmd_at(vma->vm_mm, address, pmdp, entry);
0114         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
0115     }
0116     return changed;
0117 }
0118 #endif
0119
0120 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
0121 int pmdp_clear_flush_young(struct vm_area_struct *vma,
0122                unsigned long address, pmd_t *pmdp)
0123 {
0124     int young;
0125     VM_BUG_ON(address & ~HPAGE_PMD_MASK);
0126     young = pmdp_test_and_clear_young(vma, address, pmdp);
0127     if (young)
0128         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
0129     return young;
0130 }
0131 #endif
0132
0133 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
0134 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
0135                 pmd_t *pmdp)
0136 {
0137     pmd_t pmd;
0138     VM_BUG_ON(address & ~HPAGE_PMD_MASK);
0139     VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
0140                !pmd_devmap(*pmdp));
0141     pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
0142     flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
0143     return pmd;
0144 }
0145
0146 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
0147 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
0148                 pud_t *pudp)
0149 {
0150     pud_t pud;
0151
0152     VM_BUG_ON(address & ~HPAGE_PUD_MASK);
0153     VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
0154     pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
0155     flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
0156     return pud;
0157 }
0158 #endif
0159 #endif
0160
0161 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
0162 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
0163                 pgtable_t pgtable)
0164 {
0165     assert_spin_locked(pmd_lockptr(mm, pmdp));
0166
0167     /* FIFO */
0168     if (!pmd_huge_pte(mm, pmdp))
0169         INIT_LIST_HEAD(&pgtable->lru);
0170     else
0171         list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
0172     pmd_huge_pte(mm, pmdp) = pgtable;
0173 }
0174 #endif
0175
0176 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
0177 /* no "address" argument so destroys page coloring of some arch */
0178 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
0179 {
0180     pgtable_t pgtable;
0181
0182     assert_spin_locked(pmd_lockptr(mm, pmdp));
0183
0184     /* FIFO */
0185     pgtable = pmd_huge_pte(mm, pmdp);
0186     pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
0187                               struct page, lru);
0188     if (pmd_huge_pte(mm, pmdp))
0189         list_del(&pgtable->lru);
0190     return pgtable;
0191 }
0192 #endif
0193
0194 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
0195 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
0196              pmd_t *pmdp)
0197 {
0198     pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
0199     flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
0200     return old;
0201 }
0202 #endif
0203
0204 #ifndef __HAVE_ARCH_PMDP_INVALIDATE_AD
0205 pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
0206              pmd_t *pmdp)
0207 {
0208     return pmdp_invalidate(vma, address, pmdp);
0209 }
0210 #endif
0211
0212 #ifndef pmdp_collapse_flush
0213 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
0214               pmd_t *pmdp)
0215 {
0216     /*
0217      * pmd and hugepage pte format are same. So we could
0218      * use the same function.
0219      */
0220     pmd_t pmd;
0221
0222     VM_BUG_ON(address & ~HPAGE_PMD_MASK);
0223     VM_BUG_ON(pmd_trans_huge(*pmdp));
0224     pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
0225
0226     /* collapse entails shooting down ptes not pmd */
0227     flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
0228     return pmd;
0229 }
0230 #endif
0231 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */