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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright 2017, Michael Ellerman, IBM Corporation.
*/
#ifndef _LINUX_SET_MEMORY_H_
#define _LINUX_SET_MEMORY_H_
/**
* DOC: Kernel page table permissions
*
* The set_memory() and set_direct_map() APIs update permissions of existing
* kernel mappings.
*
* The set_memory() functions operate on a range of kernel virtual addresses,
* the set_direct_map() functions operate on the direct map.
*
* The updates are not atomic: when a call fails, an arbitrary prefix of the
* range may have been updated already and there is no automatic rollback.
* A caller must restore the required permissions before reusing or freeing
* the memory.
*
* When an architecture does not implement these APIs they succeed without
* doing anything, so a return value of 0 does not mean that the permissions
* were actually changed.
*
* Callers that depend on the permissions being applied must ensure that the
* architecture supports the required operation for the target addresses. The
* Kconfig symbols alone do not guarantee this.
*
* See Documentation/mm/kernel-page-tables.rst for the details and for the
* differences between the architecture implementations.
*/
#ifdef CONFIG_ARCH_HAS_SET_MEMORY
#include <asm/set_memory.h>
#else
/**
* set_memory_ro - make a kernel mapping read-only
* @addr: page aligned start of the kernel virtual address range
* @numpages: number of pages in the range
*
* Flushes the TLB for the range.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int __must_check set_memory_ro(unsigned long addr, int numpages) { return 0; }
/**
* set_memory_rw - make a kernel mapping writable
* @addr: page aligned start of the kernel virtual address range
* @numpages: number of pages in the range
*
* Flushes the TLB for the range.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int __must_check set_memory_rw(unsigned long addr, int numpages) { return 0; }
/**
* set_memory_x - make a kernel mapping executable
* @addr: page aligned start of the kernel virtual address range
* @numpages: number of pages in the range
*
* Flushes the TLB for the range.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int __must_check set_memory_x(unsigned long addr, int numpages) { return 0; }
/**
* set_memory_nx - make a kernel mapping non-executable
* @addr: page aligned start of the kernel virtual address range
* @numpages: number of pages in the range
*
* Flushes the TLB for the range.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int __must_check set_memory_nx(unsigned long addr, int numpages) { return 0; }
#endif
#ifndef set_memory_rox
/**
* set_memory_rox - make a kernel mapping read-only and executable
* @addr: page aligned start of the kernel virtual address range
* @numpages: number of pages in the range
*
* A failure may leave the range read-only but not executable.
*
* Flushes the TLB for the range.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int set_memory_rox(unsigned long addr, int numpages)
{
int ret = set_memory_ro(addr, numpages);
if (ret)
return ret;
return set_memory_x(addr, numpages);
}
#endif
#ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP
/**
* set_direct_map_invalid_noflush - remove pages from the direct map
* @page: first page to update
* @nr: number of pages to update
*
* Makes the direct mapping of @nr pages starting at @page not present.
* The caller is responsible for any required TLB flushing.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int set_direct_map_invalid_noflush(struct page *page,
unsigned int nr)
{
return 0;
}
/**
* set_direct_map_default_noflush - restore the direct map of pages
* @page: first page to update
* @nr: number of pages to update
*
* Restores the default kernel permissions of the direct mapping of @nr
* pages starting at @page.
* The caller is responsible for any required TLB flushing.
*
* Return: 0 on success, negative error code on failure.
*/
static inline int set_direct_map_default_noflush(struct page *page,
unsigned int nr)
{
return 0;
}
static inline bool kernel_page_present(struct page *page)
{
return true;
}
#else /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
/*
* Some architectures, e.g. ARM64 can disable direct map modifications at
* boot time. Let them overrive this query.
*/
#ifndef can_set_direct_map
/**
* can_set_direct_map - check if the direct map can be modified
*
* Available with CONFIG_ARCH_HAS_SET_DIRECT_MAP. Architectures may override
* this to report whether direct map updates are enabled at runtime.
* Even though the generic implementation returns true this does not guarantee
* that every address can be updated.
*
* See Documentation/mm/kernel-page-tables.rst for the details
*
* Return: true unless the architecture reports direct map updates disabled.
*/
static inline bool can_set_direct_map(void)
{
return true;
}
#define can_set_direct_map can_set_direct_map
#endif
#endif /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
#ifdef CONFIG_X86_64
int set_mce_nospec(unsigned long pfn);
int clear_mce_nospec(unsigned long pfn);
#else
static inline int set_mce_nospec(unsigned long pfn)
{
return 0;
}
static inline int clear_mce_nospec(unsigned long pfn)
{
return 0;
}
#endif
#ifndef CONFIG_ARCH_HAS_MEM_ENCRYPT
static inline int set_memory_encrypted(unsigned long addr, int numpages)
{
return 0;
}
static inline int set_memory_decrypted(unsigned long addr, int numpages)
{
return 0;
}
#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
#endif /* _LINUX_SET_MEMORY_H_ */
|
