1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_GENERIC_SECTIONS_H_
3 #define _ASM_GENERIC_SECTIONS_H_
4
5 /* References to section boundaries */
6
7 #include <linux/compiler.h>
8 #include <linux/types.h>
9
10 /*
11 * Usage guidelines:
12 * _text, _data: architecture specific, don't use them in arch-independent code
13 * [_stext, _etext]: contains .text.* sections, may also contain .rodata.*
14 * and/or .init.* sections
15 * [_sdata, _edata]: contains .data.* sections, may also contain .rodata.*
16 * and/or .init.* sections.
17 * [__start_rodata, __end_rodata]: contains .rodata.* sections
18 * [__start_ro_after_init, __end_ro_after_init]:
19 * contains .data..ro_after_init section
20 * [__init_begin, __init_end]: contains .init.* sections, but .init.text.*
21 * may be out of this range on some architectures.
22 * [_sinittext, _einittext]: contains .init.text.* sections
23 * [__bss_start, __bss_stop]: contains BSS sections
24 *
25 * Following global variables are optional and may be unavailable on some
26 * architectures and/or kernel configurations.
27 * _text, _data
28 * __kprobes_text_start, __kprobes_text_end
29 * __entry_text_start, __entry_text_end
30 * __ctors_start, __ctors_end
31 * __irqentry_text_start, __irqentry_text_end
32 * __softirqentry_text_start, __softirqentry_text_end
33 * __start_opd, __end_opd
34 */
35 extern char _text[], _stext[], _etext[];
36 extern char _data[], _sdata[], _edata[];
37 extern char __bss_start[], __bss_stop[];
38 extern char __init_begin[], __init_end[];
39 extern char _sinittext[], _einittext[];
40 extern char __start_ro_after_init[], __end_ro_after_init[];
41 extern char _end[];
42 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
43 extern char __kprobes_text_start[], __kprobes_text_end[];
44 extern char __entry_text_start[], __entry_text_end[];
45 extern char __start_rodata[], __end_rodata[];
46 extern char __irqentry_text_start[], __irqentry_text_end[];
47 extern char __softirqentry_text_start[], __softirqentry_text_end[];
48 extern char __start_once[], __end_once[];
49
50 /* Start and end of .ctors section - used for constructor calls. */
51 extern char __ctors_start[], __ctors_end[];
52
53 /* Start and end of .opd section - used for function descriptors. */
54 extern char __start_opd[], __end_opd[];
55
56 extern __visible const void __nosave_begin, __nosave_end;
57
58 /* Function descriptor handling (if any). Override in asm/sections.h */
59 #ifndef dereference_function_descriptor
60 #define dereference_function_descriptor(p) (p)
61 #define dereference_kernel_function_descriptor(p) (p)
62 #endif
63
64 /* random extra sections (if any). Override
65 * in asm/sections.h */
66 #ifndef arch_is_kernel_text
67 static inline int arch_is_kernel_text(unsigned long addr)
68 {
69 return 0;
70 }
71 #endif
72
73 #ifndef arch_is_kernel_data
74 static inline int arch_is_kernel_data(unsigned long addr)
75 {
76 return 0;
77 }
78 #endif
79
80 /*
81 * Check if an address is part of freed initmem. This is needed on architectures
82 * with virt == phys kernel mapping, for code that wants to check if an address
83 * is part of a static object within [_stext, _end]. After initmem is freed,
84 * memory can be allocated from it, and such allocations would then have
85 * addresses within the range [_stext, _end].
86 */
87 #ifndef arch_is_kernel_initmem_freed
88 static inline int arch_is_kernel_initmem_freed(unsigned long addr)
89 {
90 return 0;
91 }
92 #endif
93
94 /**
95 * memory_contains - checks if an object is contained within a memory region
96 * @begin: virtual address of the beginning of the memory region
97 * @end: virtual address of the end of the memory region
98 * @virt: virtual address of the memory object
99 * @size: size of the memory object
100 *
101 * Returns: true if the object specified by @virt and @size is entirely
102 * contained within the memory region defined by @begin and @end, false
103 * otherwise.
104 */
105 static inline bool memory_contains(void *begin, void *end, void *virt,
106 size_t size)
107 {
108 return virt >= begin && virt + size <= end;
109 }
110
111 /**
112 * memory_intersects - checks if the region occupied by an object intersects
113 * with another memory region
114 * @begin: virtual address of the beginning of the memory regien
115 * @end: virtual address of the end of the memory region
116 * @virt: virtual address of the memory object
117 * @size: size of the memory object
118 *
119 * Returns: true if an object's memory region, specified by @virt and @size,
120 * intersects with the region specified by @begin and @end, false otherwise.
121 */
122 static inline bool memory_intersects(void *begin, void *end, void *virt,
123 size_t size)
124 {
125 void *vend = virt + size;
126
127 return (virt >= begin && virt < end) || (vend >= begin && vend < end);
128 }
129
130 /**
131 * init_section_contains - checks if an object is contained within the init
132 * section
133 * @virt: virtual address of the memory object
134 * @size: size of the memory object
135 *
136 * Returns: true if the object specified by @virt and @size is entirely
137 * contained within the init section, false otherwise.
138 */
139 static inline bool init_section_contains(void *virt, size_t size)
140 {
141 return memory_contains(__init_begin, __init_end, virt, size);
142 }
143
144 /**
145 * init_section_intersects - checks if the region occupied by an object
146 * intersects with the init section
147 * @virt: virtual address of the memory object
148 * @size: size of the memory object
149 *
150 * Returns: true if an object's memory region, specified by @virt and @size,
151 * intersects with the init section, false otherwise.
152 */
153 static inline bool init_section_intersects(void *virt, size_t size)
154 {
155 return memory_intersects(__init_begin, __init_end, virt, size);
156 }
157
158 /**
159 * is_kernel_rodata - checks if the pointer address is located in the
160 * .rodata section
161 *
162 * @addr: address to check
163 *
164 * Returns: true if the address is located in .rodata, false otherwise.
165 */
166 static inline bool is_kernel_rodata(unsigned long addr)
167 {
168 return addr >= (unsigned long)__start_rodata &&
169 addr < (unsigned long)__end_rodata;
170 }
171
172 #endif /* _ASM_GENERIC_SECTIONS_H_ */