1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_PGALLOC_H
#define _ASM_PGALLOC_H
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/threads.h>
#include <asm/processor.h>
#include <asm/fixmap.h>
#include <asm/cache.h>
/* Allocate the top level pgd (page directory)
*
* Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
* allocate the first pmd adjacent to the pgd. This means that we can
* subtract a constant offset to get to it. The pmd and pgd sizes are
* arranged so that a single pmd covers 4GB (giving a full 64-bit
* process access to 8TB) so our lookups are effectively L2 for the
* first 4GB of the kernel (i.e. for all ILP32 processes and all the
* kernel for machines with under 4GB of memory) */
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
PGD_ALLOC_ORDER);
pgd_t *actual_pgd = pgd;
if (likely(pgd != NULL)) {
memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
#if CONFIG_PGTABLE_LEVELS == 3
actual_pgd += PTRS_PER_PGD;
/* Populate first pmd with allocated memory. We mark it
* with PxD_FLAG_ATTACHED as a signal to the system that this
* pmd entry may not be cleared. */
__pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT |
PxD_FLAG_VALID |
PxD_FLAG_ATTACHED)
+ (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT));
/* The first pmd entry also is marked with PxD_FLAG_ATTACHED as
* a signal that this pmd may not be freed */
__pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
#endif
}
spin_lock_init(pgd_spinlock(actual_pgd));
return actual_pgd;
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
#if CONFIG_PGTABLE_LEVELS == 3
pgd -= PTRS_PER_PGD;
#endif
free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
}
#if CONFIG_PGTABLE_LEVELS == 3
/* Three Level Page Table Support for pmd's */
static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
{
__pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
(__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
}
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
{
pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL, PMD_ORDER);
if (pmd)
memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
return pmd;
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) {
/*
* This is the permanent pmd attached to the pgd;
* cannot free it.
* Increment the counter to compensate for the decrement
* done by generic mm code.
*/
mm_inc_nr_pmds(mm);
return;
}
free_pages((unsigned long)pmd, PMD_ORDER);
}
#else
/* Two Level Page Table Support for pmd's */
/*
* allocating and freeing a pmd is trivial: the 1-entry pmd is
* inside the pgd, so has no extra memory associated with it.
*/
#define pmd_alloc_one(mm, addr) ({ BUG(); ((pmd_t *)2); })
#define pmd_free(mm, x) do { } while (0)
#define pgd_populate(mm, pmd, pte) BUG()
#endif
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
{
#if CONFIG_PGTABLE_LEVELS == 3
/* preserve the gateway marker if this is the beginning of
* the permanent pmd */
if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
__pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
PxD_FLAG_VALID |
PxD_FLAG_ATTACHED)
+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
else
#endif
__pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID)
+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
}
#define pmd_populate(mm, pmd, pte_page) \
pmd_populate_kernel(mm, pmd, page_address(pte_page))
#define pmd_pgtable(pmd) pmd_page(pmd)
static inline pgtable_t
pte_alloc_one(struct mm_struct *mm)
{
struct page *page = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (!page)
return NULL;
if (!pgtable_page_ctor(page)) {
__free_page(page);
return NULL;
}
return page;
}
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
return pte;
}
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
free_page((unsigned long)pte);
}
static inline void pte_free(struct mm_struct *mm, struct page *pte)
{
pgtable_page_dtor(pte);
pte_free_kernel(mm, page_address(pte));
}
#define check_pgt_cache() do { } while (0)
#endif
|
