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 /**
68  * memory_contains - checks if an object is contained within a memory region
69  * @begin: virtual address of the beginning of the memory region
70  * @end: virtual address of the end of the memory region
71  * @virt: virtual address of the memory object
72  * @size: size of the memory object
73  *
74  * Returns: true if the object specified by @virt and @size is entirely
75  * contained within the memory region defined by @begin and @end, false
76  * otherwise.
77  */
78 static inline bool memory_contains(void *begin, void *end, void *virt,
79 				   size_t size)
80 {
81 	return virt >= begin && virt + size <= end;
82 }
83 
84 /**
85  * memory_intersects - checks if the region occupied by an object intersects
86  *                     with another memory region
87  * @begin: virtual address of the beginning of the memory regien
88  * @end: virtual address of the end of the memory region
89  * @virt: virtual address of the memory object
90  * @size: size of the memory object
91  *
92  * Returns: true if an object's memory region, specified by @virt and @size,
93  * intersects with the region specified by @begin and @end, false otherwise.
94  */
95 static inline bool memory_intersects(void *begin, void *end, void *virt,
96 				     size_t size)
97 {
98 	void *vend = virt + size;
99 
100 	return (virt >= begin && virt < end) || (vend >= begin && vend < end);
101 }
102 
103 /**
104  * init_section_contains - checks if an object is contained within the init
105  *                         section
106  * @virt: virtual address of the memory object
107  * @size: size of the memory object
108  *
109  * Returns: true if the object specified by @virt and @size is entirely
110  * contained within the init section, false otherwise.
111  */
112 static inline bool init_section_contains(void *virt, size_t size)
113 {
114 	return memory_contains(__init_begin, __init_end, virt, size);
115 }
116 
117 /**
118  * init_section_intersects - checks if the region occupied by an object
119  *                           intersects with the init section
120  * @virt: virtual address of the memory object
121  * @size: size of the memory object
122  *
123  * Returns: true if an object's memory region, specified by @virt and @size,
124  * intersects with the init section, false otherwise.
125  */
126 static inline bool init_section_intersects(void *virt, size_t size)
127 {
128 	return memory_intersects(__init_begin, __init_end, virt, size);
129 }
130 
131 /**
132  * is_kernel_core_data - checks if the pointer address is located in the
133  *			 .data section
134  *
135  * @addr: address to check
136  *
137  * Returns: true if the address is located in .data, false otherwise.
138  * Note: On some archs it may return true for core RODATA, and false
139  *       for others. But will always be true for core RW data.
140  */
141 static inline bool is_kernel_core_data(unsigned long addr)
142 {
143 	return addr >= (unsigned long)_sdata &&
144 	       addr < (unsigned long)_edata;
145 }
146 
147 /**
148  * is_kernel_rodata - checks if the pointer address is located in the
149  *                    .rodata section
150  *
151  * @addr: address to check
152  *
153  * Returns: true if the address is located in .rodata, false otherwise.
154  */
155 static inline bool is_kernel_rodata(unsigned long addr)
156 {
157 	return addr >= (unsigned long)__start_rodata &&
158 	       addr < (unsigned long)__end_rodata;
159 }
160 
161 /**
162  * is_kernel_inittext - checks if the pointer address is located in the
163  *                      .init.text section
164  *
165  * @addr: address to check
166  *
167  * Returns: true if the address is located in .init.text, false otherwise.
168  */
169 static inline bool is_kernel_inittext(unsigned long addr)
170 {
171 	return addr >= (unsigned long)_sinittext &&
172 	       addr < (unsigned long)_einittext;
173 }
174 
175 /**
176  * __is_kernel_text - checks if the pointer address is located in the
177  *                    .text section
178  *
179  * @addr: address to check
180  *
181  * Returns: true if the address is located in .text, false otherwise.
182  * Note: an internal helper, only check the range of _stext to _etext.
183  */
184 static inline bool __is_kernel_text(unsigned long addr)
185 {
186 	return addr >= (unsigned long)_stext &&
187 	       addr < (unsigned long)_etext;
188 }
189 
190 /**
191  * __is_kernel - checks if the pointer address is located in the kernel range
192  *
193  * @addr: address to check
194  *
195  * Returns: true if the address is located in the kernel range, false otherwise.
196  * Note: an internal helper, only check the range of _stext to _end.
197  */
198 static inline bool __is_kernel(unsigned long addr)
199 {
200 	return addr >= (unsigned long)_stext &&
201 	       addr < (unsigned long)_end;
202 }
203 
204 #endif /* _ASM_GENERIC_SECTIONS_H_ */
205