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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _ASM_PGALLOC_H |
3 | #define _ASM_PGALLOC_H | |
4 | ||
5 | #include <linux/gfp.h> | |
6 | #include <linux/mm.h> | |
7 | #include <linux/threads.h> | |
8 | #include <asm/processor.h> | |
9 | #include <asm/fixmap.h> | |
10 | ||
11 | #include <asm/cache.h> | |
12 | ||
13 | /* Allocate the top level pgd (page directory) | |
14 | * | |
15 | * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we | |
16 | * allocate the first pmd adjacent to the pgd. This means that we can | |
17 | * subtract a constant offset to get to it. The pmd and pgd sizes are | |
513e7ecd | 18 | * arranged so that a single pmd covers 4GB (giving a full 64-bit |
1da177e4 LT |
19 | * process access to 8TB) so our lookups are effectively L2 for the |
20 | * first 4GB of the kernel (i.e. for all ILP32 processes and all the | |
21 | * kernel for machines with under 4GB of memory) */ | |
22 | static inline pgd_t *pgd_alloc(struct mm_struct *mm) | |
23 | { | |
24 | pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, | |
25 | PGD_ALLOC_ORDER); | |
26 | pgd_t *actual_pgd = pgd; | |
27 | ||
28 | if (likely(pgd != NULL)) { | |
29 | memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER); | |
c19edb69 | 30 | #if CONFIG_PGTABLE_LEVELS == 3 |
1da177e4 LT |
31 | actual_pgd += PTRS_PER_PGD; |
32 | /* Populate first pmd with allocated memory. We mark it | |
33 | * with PxD_FLAG_ATTACHED as a signal to the system that this | |
34 | * pmd entry may not be cleared. */ | |
35 | __pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT | | |
36 | PxD_FLAG_VALID | | |
37 | PxD_FLAG_ATTACHED) | |
38 | + (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT)); | |
2b3f3445 | 39 | /* The first pmd entry also is marked with PxD_FLAG_ATTACHED as |
1da177e4 LT |
40 | * a signal that this pmd may not be freed */ |
41 | __pgd_val_set(*pgd, PxD_FLAG_ATTACHED); | |
42 | #endif | |
43 | } | |
44 | return actual_pgd; | |
45 | } | |
46 | ||
5e541973 | 47 | static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) |
1da177e4 | 48 | { |
c19edb69 | 49 | #if CONFIG_PGTABLE_LEVELS == 3 |
1da177e4 LT |
50 | pgd -= PTRS_PER_PGD; |
51 | #endif | |
52 | free_pages((unsigned long)pgd, PGD_ALLOC_ORDER); | |
53 | } | |
54 | ||
f24ffde4 | 55 | #if CONFIG_PGTABLE_LEVELS == 3 |
1da177e4 LT |
56 | |
57 | /* Three Level Page Table Support for pmd's */ | |
58 | ||
59 | static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd) | |
60 | { | |
61 | __pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) + | |
62 | (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT)); | |
63 | } | |
64 | ||
65 | static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address) | |
66 | { | |
aade311a | 67 | pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL, PMD_ORDER); |
1da177e4 LT |
68 | if (pmd) |
69 | memset(pmd, 0, PAGE_SIZE<<PMD_ORDER); | |
70 | return pmd; | |
71 | } | |
72 | ||
5e541973 | 73 | static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd) |
1da177e4 | 74 | { |
4c4ac9a4 | 75 | if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) { |
0e0da48d MP |
76 | /* |
77 | * This is the permanent pmd attached to the pgd; | |
78 | * cannot free it. | |
79 | * Increment the counter to compensate for the decrement | |
80 | * done by generic mm code. | |
81 | */ | |
82 | mm_inc_nr_pmds(mm); | |
1da177e4 | 83 | return; |
4c4ac9a4 | 84 | } |
1da177e4 LT |
85 | free_pages((unsigned long)pmd, PMD_ORDER); |
86 | } | |
87 | ||
88 | #else | |
89 | ||
90 | /* Two Level Page Table Support for pmd's */ | |
91 | ||
92 | /* | |
93 | * allocating and freeing a pmd is trivial: the 1-entry pmd is | |
94 | * inside the pgd, so has no extra memory associated with it. | |
95 | */ | |
96 | ||
97 | #define pmd_alloc_one(mm, addr) ({ BUG(); ((pmd_t *)2); }) | |
5e541973 | 98 | #define pmd_free(mm, x) do { } while (0) |
1da177e4 LT |
99 | #define pgd_populate(mm, pmd, pte) BUG() |
100 | ||
101 | #endif | |
102 | ||
103 | static inline void | |
104 | pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte) | |
105 | { | |
c19edb69 | 106 | #if CONFIG_PGTABLE_LEVELS == 3 |
1da177e4 LT |
107 | /* preserve the gateway marker if this is the beginning of |
108 | * the permanent pmd */ | |
109 | if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED) | |
110 | __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | | |
111 | PxD_FLAG_VALID | | |
112 | PxD_FLAG_ATTACHED) | |
113 | + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); | |
114 | else | |
115 | #endif | |
116 | __pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) | |
117 | + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)); | |
118 | } | |
119 | ||
120 | #define pmd_populate(mm, pmd, pte_page) \ | |
121 | pmd_populate_kernel(mm, pmd, page_address(pte_page)) | |
2f569afd | 122 | #define pmd_pgtable(pmd) pmd_page(pmd) |
1da177e4 | 123 | |
2f569afd | 124 | static inline pgtable_t |
1da177e4 LT |
125 | pte_alloc_one(struct mm_struct *mm, unsigned long address) |
126 | { | |
32d6bd90 | 127 | struct page *page = alloc_page(GFP_KERNEL|__GFP_ZERO); |
bc16640d KS |
128 | if (!page) |
129 | return NULL; | |
130 | if (!pgtable_page_ctor(page)) { | |
131 | __free_page(page); | |
132 | return NULL; | |
133 | } | |
1da177e4 LT |
134 | return page; |
135 | } | |
136 | ||
137 | static inline pte_t * | |
138 | pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr) | |
139 | { | |
32d6bd90 | 140 | pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO); |
1da177e4 LT |
141 | return pte; |
142 | } | |
143 | ||
5e541973 | 144 | static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) |
1da177e4 LT |
145 | { |
146 | free_page((unsigned long)pte); | |
147 | } | |
148 | ||
9aa150b8 | 149 | static inline void pte_free(struct mm_struct *mm, struct page *pte) |
2f569afd MS |
150 | { |
151 | pgtable_page_dtor(pte); | |
9aa150b8 | 152 | pte_free_kernel(mm, page_address(pte)); |
2f569afd | 153 | } |
1da177e4 | 154 | |
1da177e4 LT |
155 | #define check_pgt_cache() do { } while (0) |
156 | ||
157 | #endif |