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 /* Start and end of instrumentation protected text section */
57 extern char __noinstr_text_start[], __noinstr_text_end[];
58
59 extern __visible const void __nosave_begin, __nosave_end;
60
61 /* Function descriptor handling (if any). Override in asm/sections.h */
62 #ifndef dereference_function_descriptor
63 #define dereference_function_descriptor(p) ((void *)(p))
64 #define dereference_kernel_function_descriptor(p) ((void *)(p))
65 #endif
66
67 /* random extra sections (if any). Override
68 * in asm/sections.h */
69 #ifndef arch_is_kernel_text
arch_is_kernel_text(unsigned long addr)70 static inline int arch_is_kernel_text(unsigned long addr)
71 {
72 return 0;
73 }
74 #endif
75
76 #ifndef arch_is_kernel_data
arch_is_kernel_data(unsigned long addr)77 static inline int arch_is_kernel_data(unsigned long addr)
78 {
79 return 0;
80 }
81 #endif
82
83 /*
84 * Check if an address is part of freed initmem. This is needed on architectures
85 * with virt == phys kernel mapping, for code that wants to check if an address
86 * is part of a static object within [_stext, _end]. After initmem is freed,
87 * memory can be allocated from it, and such allocations would then have
88 * addresses within the range [_stext, _end].
89 */
90 #ifndef arch_is_kernel_initmem_freed
arch_is_kernel_initmem_freed(unsigned long addr)91 static inline int arch_is_kernel_initmem_freed(unsigned long addr)
92 {
93 return 0;
94 }
95 #endif
96
97 /**
98 * memory_contains - checks if an object is contained within a memory region
99 * @begin: virtual address of the beginning of the memory region
100 * @end: virtual address of the end of the memory region
101 * @virt: virtual address of the memory object
102 * @size: size of the memory object
103 *
104 * Returns: true if the object specified by @virt and @size is entirely
105 * contained within the memory region defined by @begin and @end, false
106 * otherwise.
107 */
memory_contains(void * begin,void * end,void * virt,size_t size)108 static inline bool memory_contains(void *begin, void *end, void *virt,
109 size_t size)
110 {
111 return virt >= begin && virt + size <= end;
112 }
113
114 /**
115 * memory_intersects - checks if the region occupied by an object intersects
116 * with another memory region
117 * @begin: virtual address of the beginning of the memory regien
118 * @end: virtual address of the end of the memory region
119 * @virt: virtual address of the memory object
120 * @size: size of the memory object
121 *
122 * Returns: true if an object's memory region, specified by @virt and @size,
123 * intersects with the region specified by @begin and @end, false otherwise.
124 */
memory_intersects(void * begin,void * end,void * virt,size_t size)125 static inline bool memory_intersects(void *begin, void *end, void *virt,
126 size_t size)
127 {
128 void *vend = virt + size;
129
130 return (virt >= begin && virt < end) || (vend >= begin && vend < end);
131 }
132
133 /**
134 * init_section_contains - checks if an object is contained within the init
135 * section
136 * @virt: virtual address of the memory object
137 * @size: size of the memory object
138 *
139 * Returns: true if the object specified by @virt and @size is entirely
140 * contained within the init section, false otherwise.
141 */
init_section_contains(void * virt,size_t size)142 static inline bool init_section_contains(void *virt, size_t size)
143 {
144 return memory_contains(__init_begin, __init_end, virt, size);
145 }
146
147 /**
148 * init_section_intersects - checks if the region occupied by an object
149 * intersects with the init section
150 * @virt: virtual address of the memory object
151 * @size: size of the memory object
152 *
153 * Returns: true if an object's memory region, specified by @virt and @size,
154 * intersects with the init section, false otherwise.
155 */
init_section_intersects(void * virt,size_t size)156 static inline bool init_section_intersects(void *virt, size_t size)
157 {
158 return memory_intersects(__init_begin, __init_end, virt, size);
159 }
160
161 /**
162 * is_kernel_rodata - checks if the pointer address is located in the
163 * .rodata section
164 *
165 * @addr: address to check
166 *
167 * Returns: true if the address is located in .rodata, false otherwise.
168 */
is_kernel_rodata(unsigned long addr)169 static inline bool is_kernel_rodata(unsigned long addr)
170 {
171 return addr >= (unsigned long)__start_rodata &&
172 addr < (unsigned long)__end_rodata;
173 }
174
175 #endif /* _ASM_GENERIC_SECTIONS_H_ */
176
