1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_GENERIC_PGALLOC_H
3 #define __ASM_GENERIC_PGALLOC_H
4 
5 #ifdef CONFIG_MMU
6 
7 #define GFP_PGTABLE_KERNEL	(GFP_KERNEL | __GFP_ZERO)
8 #define GFP_PGTABLE_USER	(GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
9 
10 /**
11  * __pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
12  * @mm: the mm_struct of the current context
13  *
14  * This function is intended for architectures that need
15  * anything beyond simple page allocation.
16  *
17  * Return: pointer to the allocated memory or %NULL on error
18  */
__pte_alloc_one_kernel(struct mm_struct * mm)19 static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm)
20 {
21 	return (pte_t *)__get_free_page(GFP_PGTABLE_KERNEL);
22 }
23 
24 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
25 /**
26  * pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
27  * @mm: the mm_struct of the current context
28  *
29  * Return: pointer to the allocated memory or %NULL on error
30  */
pte_alloc_one_kernel(struct mm_struct * mm)31 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
32 {
33 	return __pte_alloc_one_kernel(mm);
34 }
35 #endif
36 
37 /**
38  * pte_free_kernel - free PTE-level kernel page table page
39  * @mm: the mm_struct of the current context
40  * @pte: pointer to the memory containing the page table
41  */
pte_free_kernel(struct mm_struct * mm,pte_t * pte)42 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
43 {
44 	free_page((unsigned long)pte);
45 }
46 
47 /**
48  * __pte_alloc_one - allocate a page for PTE-level user page table
49  * @mm: the mm_struct of the current context
50  * @gfp: GFP flags to use for the allocation
51  *
52  * Allocates a page and runs the pgtable_pte_page_ctor().
53  *
54  * This function is intended for architectures that need
55  * anything beyond simple page allocation or must have custom GFP flags.
56  *
57  * Return: `struct page` initialized as page table or %NULL on error
58  */
__pte_alloc_one(struct mm_struct * mm,gfp_t gfp)59 static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp)
60 {
61 	struct page *pte;
62 
63 	pte = alloc_page(gfp);
64 	if (!pte)
65 		return NULL;
66 	if (!pgtable_pte_page_ctor(pte)) {
67 		__free_page(pte);
68 		return NULL;
69 	}
70 
71 	return pte;
72 }
73 
74 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE
75 /**
76  * pte_alloc_one - allocate a page for PTE-level user page table
77  * @mm: the mm_struct of the current context
78  *
79  * Allocates a page and runs the pgtable_pte_page_ctor().
80  *
81  * Return: `struct page` initialized as page table or %NULL on error
82  */
pte_alloc_one(struct mm_struct * mm)83 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
84 {
85 	return __pte_alloc_one(mm, GFP_PGTABLE_USER);
86 }
87 #endif
88 
89 /*
90  * Should really implement gc for free page table pages. This could be
91  * done with a reference count in struct page.
92  */
93 
94 /**
95  * pte_free - free PTE-level user page table page
96  * @mm: the mm_struct of the current context
97  * @pte_page: the `struct page` representing the page table
98  */
pte_free(struct mm_struct * mm,struct page * pte_page)99 static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
100 {
101 	pgtable_pte_page_dtor(pte_page);
102 	__free_page(pte_page);
103 }
104 
105 
106 #if CONFIG_PGTABLE_LEVELS > 2
107 
108 #ifndef __HAVE_ARCH_PMD_ALLOC_ONE
109 /**
110  * pmd_alloc_one - allocate a page for PMD-level page table
111  * @mm: the mm_struct of the current context
112  *
113  * Allocates a page and runs the pgtable_pmd_page_ctor().
114  * Allocations use %GFP_PGTABLE_USER in user context and
115  * %GFP_PGTABLE_KERNEL in kernel context.
116  *
117  * Return: pointer to the allocated memory or %NULL on error
118  */
pmd_alloc_one(struct mm_struct * mm,unsigned long addr)119 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
120 {
121 	struct page *page;
122 	gfp_t gfp = GFP_PGTABLE_USER;
123 
124 	if (mm == &init_mm)
125 		gfp = GFP_PGTABLE_KERNEL;
126 	page = alloc_pages(gfp, 0);
127 	if (!page)
128 		return NULL;
129 	if (!pgtable_pmd_page_ctor(page)) {
130 		__free_pages(page, 0);
131 		return NULL;
132 	}
133 	return (pmd_t *)page_address(page);
134 }
135 #endif
136 
137 #ifndef __HAVE_ARCH_PMD_FREE
pmd_free(struct mm_struct * mm,pmd_t * pmd)138 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
139 {
140 	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
141 	pgtable_pmd_page_dtor(virt_to_page(pmd));
142 	free_page((unsigned long)pmd);
143 }
144 #endif
145 
146 #endif /* CONFIG_PGTABLE_LEVELS > 2 */
147 
148 #if CONFIG_PGTABLE_LEVELS > 3
149 
150 #ifndef __HAVE_ARCH_PUD_ALLOC_ONE
151 /**
152  * pud_alloc_one - allocate a page for PUD-level page table
153  * @mm: the mm_struct of the current context
154  *
155  * Allocates a page using %GFP_PGTABLE_USER for user context and
156  * %GFP_PGTABLE_KERNEL for kernel context.
157  *
158  * Return: pointer to the allocated memory or %NULL on error
159  */
pud_alloc_one(struct mm_struct * mm,unsigned long addr)160 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
161 {
162 	gfp_t gfp = GFP_PGTABLE_USER;
163 
164 	if (mm == &init_mm)
165 		gfp = GFP_PGTABLE_KERNEL;
166 	return (pud_t *)get_zeroed_page(gfp);
167 }
168 #endif
169 
pud_free(struct mm_struct * mm,pud_t * pud)170 static inline void pud_free(struct mm_struct *mm, pud_t *pud)
171 {
172 	BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
173 	free_page((unsigned long)pud);
174 }
175 
176 #endif /* CONFIG_PGTABLE_LEVELS > 3 */
177 
178 #ifndef __HAVE_ARCH_PGD_FREE
pgd_free(struct mm_struct * mm,pgd_t * pgd)179 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
180 {
181 	free_page((unsigned long)pgd);
182 }
183 #endif
184 
185 #endif /* CONFIG_MMU */
186 
187 #endif /* __ASM_GENERIC_PGALLOC_H */
188