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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
19void pgd_clear_bad(pgd_t *pgd)
20{
21 pgd_ERROR(*pgd);
22 pgd_clear(pgd);
23}
24
25void pud_clear_bad(pud_t *pud)
26{
27 pud_ERROR(*pud);
28 pud_clear(pud);
29}
30
31void 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 */
47int 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
61int 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
73pte_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
102int 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
117int 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
130pmd_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
143void 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
155void 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 */
171pgtable_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
191void 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
201pmd_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 */