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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  mm/pgtable-generic.c
4  *
5  *  Generic pgtable methods declared in linux/pgtable.h
6  *
7  *  Copyright (C) 2010  Linus Torvalds
8  */
9 
10 #include <linux/pagemap.h>
11 #include <linux/hugetlb.h>
12 #include <linux/pgtable.h>
13 #include <asm/tlb.h>
14 
15 /*
16  * If a p?d_bad entry is found while walking page tables, report
17  * the error, before resetting entry to p?d_none.  Usually (but
18  * very seldom) called out from the p?d_none_or_clear_bad macros.
19  */
20 
pgd_clear_bad(pgd_t * pgd)21 void pgd_clear_bad(pgd_t *pgd)
22 {
23 	pgd_ERROR(*pgd);
24 	pgd_clear(pgd);
25 }
26 
27 #ifndef __PAGETABLE_P4D_FOLDED
p4d_clear_bad(p4d_t * p4d)28 void p4d_clear_bad(p4d_t *p4d)
29 {
30 	p4d_ERROR(*p4d);
31 	p4d_clear(p4d);
32 }
33 #endif
34 
35 #ifndef __PAGETABLE_PUD_FOLDED
pud_clear_bad(pud_t * pud)36 void pud_clear_bad(pud_t *pud)
37 {
38 	pud_ERROR(*pud);
39 	pud_clear(pud);
40 }
41 #endif
42 
43 /*
44  * Note that the pmd variant below can't be stub'ed out just as for p4d/pud
45  * above. pmd folding is special and typically pmd_* macros refer to upper
46  * level even when folded
47  */
pmd_clear_bad(pmd_t * pmd)48 void pmd_clear_bad(pmd_t *pmd)
49 {
50 	pmd_ERROR(*pmd);
51 	pmd_clear(pmd);
52 }
53 
54 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
55 /*
56  * Only sets the access flags (dirty, accessed), as well as write
57  * permission. Furthermore, we know it always gets set to a "more
58  * permissive" setting, which allows most architectures to optimize
59  * this. We return whether the PTE actually changed, which in turn
60  * instructs the caller to do things like update__mmu_cache.  This
61  * used to be done in the caller, but sparc needs minor faults to
62  * force that call on sun4c so we changed this macro slightly
63  */
ptep_set_access_flags(struct vm_area_struct * vma,unsigned long address,pte_t * ptep,pte_t entry,int dirty)64 int ptep_set_access_flags(struct vm_area_struct *vma,
65 			  unsigned long address, pte_t *ptep,
66 			  pte_t entry, int dirty)
67 {
68 	int changed = !pte_same(*ptep, entry);
69 	if (changed) {
70 		set_pte_at(vma->vm_mm, address, ptep, entry);
71 		flush_tlb_fix_spurious_fault(vma, address);
72 	}
73 	return changed;
74 }
75 #endif
76 
77 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
ptep_clear_flush_young(struct vm_area_struct * vma,unsigned long address,pte_t * ptep)78 int ptep_clear_flush_young(struct vm_area_struct *vma,
79 			   unsigned long address, pte_t *ptep)
80 {
81 	int young;
82 	young = ptep_test_and_clear_young(vma, address, ptep);
83 	if (young)
84 		flush_tlb_page(vma, address);
85 	return young;
86 }
87 #endif
88 
89 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
ptep_clear_flush(struct vm_area_struct * vma,unsigned long address,pte_t * ptep)90 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
91 		       pte_t *ptep)
92 {
93 	struct mm_struct *mm = (vma)->vm_mm;
94 	pte_t pte;
95 	pte = ptep_get_and_clear(mm, address, ptep);
96 	if (pte_accessible(mm, pte))
97 		flush_tlb_page(vma, address);
98 	return pte;
99 }
100 #endif
101 
102 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
103 
104 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
pmdp_set_access_flags(struct vm_area_struct * vma,unsigned long address,pmd_t * pmdp,pmd_t entry,int dirty)105 int pmdp_set_access_flags(struct vm_area_struct *vma,
106 			  unsigned long address, pmd_t *pmdp,
107 			  pmd_t entry, int dirty)
108 {
109 	int changed = !pmd_same(*pmdp, entry);
110 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
111 	if (changed) {
112 		set_pmd_at(vma->vm_mm, address, pmdp, entry);
113 		flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
114 	}
115 	return changed;
116 }
117 #endif
118 
119 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
pmdp_clear_flush_young(struct vm_area_struct * vma,unsigned long address,pmd_t * pmdp)120 int pmdp_clear_flush_young(struct vm_area_struct *vma,
121 			   unsigned long address, pmd_t *pmdp)
122 {
123 	int young;
124 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
125 	young = pmdp_test_and_clear_young(vma, address, pmdp);
126 	if (young)
127 		flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
128 	return young;
129 }
130 #endif
131 
132 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
pmdp_huge_clear_flush(struct vm_area_struct * vma,unsigned long address,pmd_t * pmdp)133 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
134 			    pmd_t *pmdp)
135 {
136 	pmd_t pmd;
137 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
138 	VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
139 			   !pmd_devmap(*pmdp));
140 	pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
141 	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
142 	return pmd;
143 }
144 
145 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
pudp_huge_clear_flush(struct vm_area_struct * vma,unsigned long address,pud_t * pudp)146 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
147 			    pud_t *pudp)
148 {
149 	pud_t pud;
150 
151 	VM_BUG_ON(address & ~HPAGE_PUD_MASK);
152 	VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
153 	pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
154 	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
155 	return pud;
156 }
157 #endif
158 #endif
159 
160 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
pgtable_trans_huge_deposit(struct mm_struct * mm,pmd_t * pmdp,pgtable_t pgtable)161 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
162 				pgtable_t pgtable)
163 {
164 	assert_spin_locked(pmd_lockptr(mm, pmdp));
165 
166 	/* FIFO */
167 	if (!pmd_huge_pte(mm, pmdp))
168 		INIT_LIST_HEAD(&pgtable->lru);
169 	else
170 		list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
171 	pmd_huge_pte(mm, pmdp) = pgtable;
172 }
173 #endif
174 
175 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
176 /* no "address" argument so destroys page coloring of some arch */
pgtable_trans_huge_withdraw(struct mm_struct * mm,pmd_t * pmdp)177 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
178 {
179 	pgtable_t pgtable;
180 
181 	assert_spin_locked(pmd_lockptr(mm, pmdp));
182 
183 	/* FIFO */
184 	pgtable = pmd_huge_pte(mm, pmdp);
185 	pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
186 							  struct page, lru);
187 	if (pmd_huge_pte(mm, pmdp))
188 		list_del(&pgtable->lru);
189 	return pgtable;
190 }
191 #endif
192 
193 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
pmdp_invalidate(struct vm_area_struct * vma,unsigned long address,pmd_t * pmdp)194 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
195 		     pmd_t *pmdp)
196 {
197 	pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
198 	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
199 	return old;
200 }
201 #endif
202 
203 #ifndef pmdp_collapse_flush
pmdp_collapse_flush(struct vm_area_struct * vma,unsigned long address,pmd_t * pmdp)204 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
205 			  pmd_t *pmdp)
206 {
207 	/*
208 	 * pmd and hugepage pte format are same. So we could
209 	 * use the same function.
210 	 */
211 	pmd_t pmd;
212 
213 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
214 	VM_BUG_ON(pmd_trans_huge(*pmdp));
215 	pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
216 
217 	/* collapse entails shooting down ptes not pmd */
218 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
219 	return pmd;
220 }
221 #endif
222 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
223