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 #ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
63 void *dereference_function_descriptor(void *ptr);
64 void *dereference_kernel_function_descriptor(void *ptr);
65 #else
66 #define dereference_function_descriptor(p) ((void *)(p))
67 #define dereference_kernel_function_descriptor(p) ((void *)(p))
68
69 /* An address is simply the address of the function. */
70 typedef struct {
71 unsigned long addr;
72 } func_desc_t;
73 #endif
74
75 static inline bool have_function_descriptors(void)
76 {
77 return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS);
78 }
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 region
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 if (virt < end && vend > begin)
114 return true;
115
116 return false;
117 }
118
119 /**
120 * init_section_contains - checks if an object is contained within the init
121 * section
122 * @virt: virtual address of the memory object
123 * @size: size of the memory object
124 *
125 * Returns: true if the object specified by @virt and @size is entirely
126 * contained within the init section, false otherwise.
127 */
128 static inline bool init_section_contains(void *virt, size_t size)
129 {
130 return memory_contains(__init_begin, __init_end, virt, size);
131 }
132
133 /**
134 * init_section_intersects - checks if the region occupied by an object
135 * intersects with the init section
136 * @virt: virtual address of the memory object
137 * @size: size of the memory object
138 *
139 * Returns: true if an object's memory region, specified by @virt and @size,
140 * intersects with the init section, false otherwise.
141 */
142 static inline bool init_section_intersects(void *virt, size_t size)
143 {
144 return memory_intersects(__init_begin, __init_end, virt, size);
145 }
146
147 /**
148 * is_kernel_core_data - checks if the pointer address is located in the
149 * .data or .bss section
150 *
151 * @addr: address to check
152 *
153 * Returns: true if the address is located in .data or .bss, false otherwise.
154 * Note: On some archs it may return true for core RODATA, and false
155 * for others. But will always be true for core RW data.
156 */
157 static inline bool is_kernel_core_data(unsigned long addr)
158 {
159 if (addr >= (unsigned long)_sdata && addr < (unsigned long)_edata)
160 return true;
161
162 if (addr >= (unsigned long)__bss_start &&
163 addr < (unsigned long)__bss_stop)
164 return true;
165
166 return false;
167 }
168
169 /**
170 * is_kernel_rodata - checks if the pointer address is located in the
171 * .rodata section
172 *
173 * @addr: address to check
174 *
175 * Returns: true if the address is located in .rodata, false otherwise.
176 */
177 static inline bool is_kernel_rodata(unsigned long addr)
178 {
179 return addr >= (unsigned long)__start_rodata &&
180 addr < (unsigned long)__end_rodata;
181 }
182
183 static inline bool is_kernel_ro_after_init(unsigned long addr)
184 {
185 return addr >= (unsigned long)__start_ro_after_init &&
186 addr < (unsigned long)__end_ro_after_init;
187 }
188 /**
189 * is_kernel_inittext - checks if the pointer address is located in the
190 * .init.text section
191 *
192 * @addr: address to check
193 *
194 * Returns: true if the address is located in .init.text, false otherwise.
195 */
196 static inline bool is_kernel_inittext(unsigned long addr)
197 {
198 return addr >= (unsigned long)_sinittext &&
199 addr < (unsigned long)_einittext;
200 }
201
202 /**
203 * __is_kernel_text - checks if the pointer address is located in the
204 * .text section
205 *
206 * @addr: address to check
207 *
208 * Returns: true if the address is located in .text, false otherwise.
209 * Note: an internal helper, only check the range of _stext to _etext.
210 */
211 static inline bool __is_kernel_text(unsigned long addr)
212 {
213 return addr >= (unsigned long)_stext &&
214 addr < (unsigned long)_etext;
215 }
216
217 /**
218 * __is_kernel - checks if the pointer address is located in the kernel range
219 *
220 * @addr: address to check
221 *
222 * Returns: true if the address is located in the kernel range, false otherwise.
223 * Note: an internal helper, check the range of _stext to _end,
224 * and range from __init_begin to __init_end, which can be outside
225 * of the _stext to _end range.
226 */
227 static inline bool __is_kernel(unsigned long addr)
228 {
229 return ((addr >= (unsigned long)_stext &&
230 addr < (unsigned long)_end) ||
231 (addr >= (unsigned long)__init_begin &&
232 addr < (unsigned long)__init_end));
233 }
234
235 #endif /* _ASM_GENERIC_SECTIONS_H_ */
236
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