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