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  */
34 extern char _text[], _stext[], _etext[];
35 extern char _data[], _sdata[], _edata[];
36 extern char __bss_start[], __bss_stop[];
37 extern char __init_begin[], __init_end[];
38 extern char _sinittext[], _einittext[];
39 extern char __start_ro_after_init[], __end_ro_after_init[];
40 extern char _end[];
41 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
42 extern char __kprobes_text_start[], __kprobes_text_end[];
43 extern char __entry_text_start[], __entry_text_end[];
44 extern char __start_rodata[], __end_rodata[];
45 extern char __irqentry_text_start[], __irqentry_text_end[];
46 extern char __softirqentry_text_start[], __softirqentry_text_end[];
47 extern char __start_once[], __end_once[];
48 
49 /* Start and end of .ctors section - used for constructor calls. */
50 extern char __ctors_start[], __ctors_end[];
51 
52 extern __visible const void __nosave_begin, __nosave_end;
53 
54 /* function descriptor handling (if any).  Override
55  * in asm/sections.h */
56 #ifndef dereference_function_descriptor
57 #define dereference_function_descriptor(p) (p)
58 #endif
59 
60 /* random extra sections (if any).  Override
61  * in asm/sections.h */
62 #ifndef arch_is_kernel_text
63 static inline int arch_is_kernel_text(unsigned long addr)
64 {
65 	return 0;
66 }
67 #endif
68 
69 #ifndef arch_is_kernel_data
70 static inline int arch_is_kernel_data(unsigned long addr)
71 {
72 	return 0;
73 }
74 #endif
75 
76 /**
77  * memory_contains - checks if an object is contained within a memory region
78  * @begin: virtual address of the beginning of the memory region
79  * @end: virtual address of the end of the memory region
80  * @virt: virtual address of the memory object
81  * @size: size of the memory object
82  *
83  * Returns: true if the object specified by @virt and @size is entirely
84  * contained within the memory region defined by @begin and @end, false
85  * otherwise.
86  */
87 static inline bool memory_contains(void *begin, void *end, void *virt,
88 				   size_t size)
89 {
90 	return virt >= begin && virt + size <= end;
91 }
92 
93 /**
94  * memory_intersects - checks if the region occupied by an object intersects
95  *                     with another memory region
96  * @begin: virtual address of the beginning of the memory regien
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 an object's memory region, specified by @virt and @size,
102  * intersects with the region specified by @begin and @end, false otherwise.
103  */
104 static inline bool memory_intersects(void *begin, void *end, void *virt,
105 				     size_t size)
106 {
107 	void *vend = virt + size;
108 
109 	return (virt >= begin && virt < end) || (vend >= begin && vend < end);
110 }
111 
112 /**
113  * init_section_contains - checks if an object is contained within the init
114  *                         section
115  * @virt: virtual address of the memory object
116  * @size: size of the memory object
117  *
118  * Returns: true if the object specified by @virt and @size is entirely
119  * contained within the init section, false otherwise.
120  */
121 static inline bool init_section_contains(void *virt, size_t size)
122 {
123 	return memory_contains(__init_begin, __init_end, virt, size);
124 }
125 
126 /**
127  * init_section_intersects - checks if the region occupied by an object
128  *                           intersects with the init section
129  * @virt: virtual address of the memory object
130  * @size: size of the memory object
131  *
132  * Returns: true if an object's memory region, specified by @virt and @size,
133  * intersects with the init section, false otherwise.
134  */
135 static inline bool init_section_intersects(void *virt, size_t size)
136 {
137 	return memory_intersects(__init_begin, __init_end, virt, size);
138 }
139 
140 #endif /* _ASM_GENERIC_SECTIONS_H_ */
141