1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  *  arch/arm/include/asm/pgalloc.h
4  *
5  *  Copyright (C) 2000-2001 Russell King
6  */
7 #ifndef _ASMARM_PGALLOC_H
8 #define _ASMARM_PGALLOC_H
9 
10 #include <linux/pagemap.h>
11 
12 #include <asm/domain.h>
13 #include <asm/pgtable-hwdef.h>
14 #include <asm/processor.h>
15 #include <asm/cacheflush.h>
16 #include <asm/tlbflush.h>
17 
18 #ifdef CONFIG_MMU
19 
20 #define _PAGE_USER_TABLE	(PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_USER))
21 #define _PAGE_KERNEL_TABLE	(PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_KERNEL))
22 
23 #ifdef CONFIG_ARM_LPAE
24 #define PGD_SIZE		(PTRS_PER_PGD * sizeof(pgd_t))
25 
pud_populate(struct mm_struct * mm,pud_t * pud,pmd_t * pmd)26 static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
27 {
28 	set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
29 }
30 
31 #else	/* !CONFIG_ARM_LPAE */
32 #define PGD_SIZE		(PAGE_SIZE << 2)
33 
34 /*
35  * Since we have only two-level page tables, these are trivial
36  */
37 #define pmd_alloc_one(mm,addr)		({ BUG(); ((pmd_t *)2); })
38 #define pmd_free(mm, pmd)		do { } while (0)
39 #ifdef CONFIG_KASAN
40 /* The KASan core unconditionally calls pud_populate() on all architectures */
41 #define pud_populate(mm,pmd,pte)	do { } while (0)
42 #else
43 #define pud_populate(mm,pmd,pte)	BUG()
44 #endif
45 #endif	/* CONFIG_ARM_LPAE */
46 
47 extern pgd_t *pgd_alloc(struct mm_struct *mm);
48 extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
49 
clean_pte_table(pte_t * pte)50 static inline void clean_pte_table(pte_t *pte)
51 {
52 	clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
53 }
54 
55 /*
56  * Allocate one PTE table.
57  *
58  * This actually allocates two hardware PTE tables, but we wrap this up
59  * into one table thus:
60  *
61  *  +------------+
62  *  | Linux pt 0 |
63  *  +------------+
64  *  | Linux pt 1 |
65  *  +------------+
66  *  |  h/w pt 0  |
67  *  +------------+
68  *  |  h/w pt 1  |
69  *  +------------+
70  */
71 
72 #define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
73 #define __HAVE_ARCH_PTE_ALLOC_ONE
74 #define __HAVE_ARCH_PGD_FREE
75 #include <asm-generic/pgalloc.h>
76 
77 static inline pte_t *
pte_alloc_one_kernel(struct mm_struct * mm)78 pte_alloc_one_kernel(struct mm_struct *mm)
79 {
80 	pte_t *pte = __pte_alloc_one_kernel(mm);
81 
82 	if (pte)
83 		clean_pte_table(pte);
84 
85 	return pte;
86 }
87 
88 #ifdef CONFIG_HIGHPTE
89 #define PGTABLE_HIGHMEM __GFP_HIGHMEM
90 #else
91 #define PGTABLE_HIGHMEM 0
92 #endif
93 
94 static inline pgtable_t
pte_alloc_one(struct mm_struct * mm)95 pte_alloc_one(struct mm_struct *mm)
96 {
97 	struct page *pte;
98 
99 	pte = __pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM);
100 	if (!pte)
101 		return NULL;
102 	if (!PageHighMem(pte))
103 		clean_pte_table(page_address(pte));
104 	return pte;
105 }
106 
__pmd_populate(pmd_t * pmdp,phys_addr_t pte,pmdval_t prot)107 static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
108 				  pmdval_t prot)
109 {
110 	pmdval_t pmdval = (pte + PTE_HWTABLE_OFF) | prot;
111 	pmdp[0] = __pmd(pmdval);
112 #ifndef CONFIG_ARM_LPAE
113 	pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
114 #endif
115 	flush_pmd_entry(pmdp);
116 }
117 
118 /*
119  * Populate the pmdp entry with a pointer to the pte.  This pmd is part
120  * of the mm address space.
121  *
122  * Ensure that we always set both PMD entries.
123  */
124 static inline void
pmd_populate_kernel(struct mm_struct * mm,pmd_t * pmdp,pte_t * ptep)125 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
126 {
127 	/*
128 	 * The pmd must be loaded with the physical address of the PTE table
129 	 */
130 	__pmd_populate(pmdp, __pa(ptep), _PAGE_KERNEL_TABLE);
131 }
132 
133 static inline void
pmd_populate(struct mm_struct * mm,pmd_t * pmdp,pgtable_t ptep)134 pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
135 {
136 	extern pmdval_t user_pmd_table;
137 	pmdval_t prot;
138 
139 	if (__LINUX_ARM_ARCH__ >= 6 && !IS_ENABLED(CONFIG_ARM_LPAE))
140 		prot = user_pmd_table;
141 	else
142 		prot = _PAGE_USER_TABLE;
143 
144 	__pmd_populate(pmdp, page_to_phys(ptep), prot);
145 }
146 
147 #endif /* CONFIG_MMU */
148 
149 #endif
150