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