1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_EXECMEM_ALLOC_H
3 #define _LINUX_EXECMEM_ALLOC_H
4
5 #include <linux/types.h>
6 #include <linux/moduleloader.h>
7 #include <linux/cleanup.h>
8
9 #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
10 !defined(CONFIG_KASAN_VMALLOC)
11 #include <linux/kasan.h>
12 #define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
13 #else
14 #define MODULE_ALIGN PAGE_SIZE
15 #endif
16
17 /**
18 * enum execmem_type - types of executable memory ranges
19 *
20 * There are several subsystems that allocate executable memory.
21 * Architectures define different restrictions on placement,
22 * permissions, alignment and other parameters for memory that can be used
23 * by these subsystems.
24 * Types in this enum identify subsystems that allocate executable memory
25 * and let architectures define parameters for ranges suitable for
26 * allocations by each subsystem.
27 *
28 * @EXECMEM_DEFAULT: default parameters that would be used for types that
29 * are not explicitly defined.
30 * @EXECMEM_MODULE_TEXT: parameters for module text sections
31 * @EXECMEM_KPROBES: parameters for kprobes
32 * @EXECMEM_FTRACE: parameters for ftrace
33 * @EXECMEM_BPF: parameters for BPF
34 * @EXECMEM_MODULE_DATA: parameters for module data sections
35 * @EXECMEM_TYPE_MAX:
36 */
37 enum execmem_type {
38 EXECMEM_DEFAULT,
39 EXECMEM_MODULE_TEXT = EXECMEM_DEFAULT,
40 EXECMEM_KPROBES,
41 EXECMEM_FTRACE,
42 EXECMEM_BPF,
43 EXECMEM_MODULE_DATA,
44 EXECMEM_TYPE_MAX,
45 };
46
47 /**
48 * enum execmem_range_flags - options for executable memory allocations
49 * @EXECMEM_KASAN_SHADOW: allocate kasan shadow
50 */
51 enum execmem_range_flags {
52 EXECMEM_KASAN_SHADOW = (1 << 0),
53 };
54
55 /**
56 * struct execmem_range - definition of an address space suitable for code and
57 * related data allocations
58 * @start: address space start
59 * @end: address space end (inclusive)
60 * @fallback_start: start of the secondary address space range for fallback
61 * allocations on architectures that require it
62 * @fallback_end: start of the secondary address space (inclusive)
63 * @pgprot: permissions for memory in this address space
64 * @alignment: alignment required for text allocations
65 * @flags: options for memory allocations for this range
66 */
67 struct execmem_range {
68 unsigned long start;
69 unsigned long end;
70 unsigned long fallback_start;
71 unsigned long fallback_end;
72 pgprot_t pgprot;
73 unsigned int alignment;
74 enum execmem_range_flags flags;
75 };
76
77 /**
78 * struct execmem_info - architecture parameters for code allocations
79 * @ranges: array of parameter sets defining architecture specific
80 * parameters for executable memory allocations. The ranges that are not
81 * explicitly initialized by an architecture use parameters defined for
82 * @EXECMEM_DEFAULT.
83 */
84 struct execmem_info {
85 struct execmem_range ranges[EXECMEM_TYPE_MAX];
86 };
87
88 /**
89 * execmem_arch_setup - define parameters for allocations of executable memory
90 *
91 * A hook for architectures to define parameters for allocations of
92 * executable memory. These parameters should be filled into the
93 * @execmem_info structure.
94 *
95 * For architectures that do not implement this method a default set of
96 * parameters will be used
97 *
98 * Return: a structure defining architecture parameters and restrictions
99 * for allocations of executable memory
100 */
101 struct execmem_info *execmem_arch_setup(void);
102
103 /**
104 * execmem_alloc - allocate executable memory
105 * @type: type of the allocation
106 * @size: how many bytes of memory are required
107 *
108 * Allocates memory that will contain executable code, either generated or
109 * loaded from kernel modules.
110 *
111 * Allocates memory that will contain data coupled with executable code,
112 * like data sections in kernel modules.
113 *
114 * The memory will have protections defined by architecture for executable
115 * region of the @type.
116 *
117 * Return: a pointer to the allocated memory or %NULL
118 */
119 void *execmem_alloc(enum execmem_type type, size_t size);
120
121 /**
122 * execmem_free - free executable memory
123 * @ptr: pointer to the memory that should be freed
124 */
125 void execmem_free(void *ptr);
126
127 DEFINE_FREE(execmem, void *, if (_T) execmem_free(_T));
128
129 #ifdef CONFIG_MMU
130 /**
131 * execmem_vmap - create virtual mapping for EXECMEM_MODULE_DATA memory
132 * @size: size of the virtual mapping in bytes
133 *
134 * Maps virtually contiguous area in the range suitable for EXECMEM_MODULE_DATA.
135 *
136 * Return: the area descriptor on success or %NULL on failure.
137 */
138 struct vm_struct *execmem_vmap(size_t size);
139 #endif
140
141 #if defined(CONFIG_EXECMEM) && !defined(CONFIG_ARCH_WANTS_EXECMEM_LATE)
142 void execmem_init(void);
143 #else
execmem_init(void)144 static inline void execmem_init(void) {}
145 #endif
146
147 #endif /* _LINUX_EXECMEM_ALLOC_H */
148