Execution of Livemigration through Yardstick
[kvmfornfv.git] / kernel / mm / pgtable-generic.c
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
214         /* collapse entails shooting down ptes not pmd */
215         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
216         return pmd;
217 }
218 #endif
219 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */