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  * memory_contains - checks if an object is contained within a memory region
82  * @begin: virtual address of the beginning of the memory region
83  * @end: virtual address of the end of the memory region
84  * @virt: virtual address of the memory object
85  * @size: size of the memory object
86  *
87  * Returns: true if the object specified by @virt and @size is entirely
88  * contained within the memory region defined by @begin and @end, false
89  * otherwise.
90  */
91 static inline bool memory_contains(void *begin, void *end, void *virt,
92 				   size_t size)
93 {
94 	return virt >= begin && virt + size <= end;
95 }
96 
97 /**
98  * memory_intersects - checks if the region occupied by an object intersects
99  *                     with another memory region
100  * @begin: virtual address of the beginning of the memory regien
101  * @end: virtual address of the end of the memory region
102  * @virt: virtual address of the memory object
103  * @size: size of the memory object
104  *
105  * Returns: true if an object's memory region, specified by @virt and @size,
106  * intersects with the region specified by @begin and @end, false otherwise.
107  */
108 static inline bool memory_intersects(void *begin, void *end, void *virt,
109 				     size_t size)
110 {
111 	void *vend = virt + size;
112 
113 	return (virt >= begin && virt < end) || (vend >= begin && vend < end);
114 }
115 
116 /**
117  * init_section_contains - checks if an object is contained within the init
118  *                         section
119  * @virt: virtual address of the memory object
120  * @size: size of the memory object
121  *
122  * Returns: true if the object specified by @virt and @size is entirely
123  * contained within the init section, false otherwise.
124  */
125 static inline bool init_section_contains(void *virt, size_t size)
126 {
127 	return memory_contains(__init_begin, __init_end, virt, size);
128 }
129 
130 /**
131  * init_section_intersects - checks if the region occupied by an object
132  *                           intersects with the init section
133  * @virt: virtual address of the memory object
134  * @size: size of the memory object
135  *
136  * Returns: true if an object's memory region, specified by @virt and @size,
137  * intersects with the init section, false otherwise.
138  */
139 static inline bool init_section_intersects(void *virt, size_t size)
140 {
141 	return memory_intersects(__init_begin, __init_end, virt, size);
142 }
143 
144 /**
145  * is_kernel_rodata - checks if the pointer address is located in the
146  *                    .rodata section
147  *
148  * @addr: address to check
149  *
150  * Returns: true if the address is located in .rodata, false otherwise.
151  */
152 static inline bool is_kernel_rodata(unsigned long addr)
153 {
154 	return addr >= (unsigned long)__start_rodata &&
155 	       addr < (unsigned long)__end_rodata;
156 }
157 
158 #endif /* _ASM_GENERIC_SECTIONS_H_ */
159