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 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_core_data - checks if the pointer address is located in the
146  *			 .data or .bss section
147  *
148  * @addr: address to check
149  *
150  * Returns: true if the address is located in .data or .bss, false otherwise.
151  * Note: On some archs it may return true for core RODATA, and false
152  *       for others. But will always be true for core RW data.
153  */
154 static inline bool is_kernel_core_data(unsigned long addr)
155 {
156 	if (addr >= (unsigned long)_sdata && addr < (unsigned long)_edata)
157 		return true;
158 
159 	if (addr >= (unsigned long)__bss_start &&
160 	    addr < (unsigned long)__bss_stop)
161 		return true;
162 
163 	return false;
164 }
165 
166 /**
167  * is_kernel_rodata - checks if the pointer address is located in the
168  *                    .rodata section
169  *
170  * @addr: address to check
171  *
172  * Returns: true if the address is located in .rodata, false otherwise.
173  */
174 static inline bool is_kernel_rodata(unsigned long addr)
175 {
176 	return addr >= (unsigned long)__start_rodata &&
177 	       addr < (unsigned long)__end_rodata;
178 }
179 
180 /**
181  * is_kernel_inittext - checks if the pointer address is located in the
182  *                      .init.text section
183  *
184  * @addr: address to check
185  *
186  * Returns: true if the address is located in .init.text, false otherwise.
187  */
188 static inline bool is_kernel_inittext(unsigned long addr)
189 {
190 	return addr >= (unsigned long)_sinittext &&
191 	       addr < (unsigned long)_einittext;
192 }
193 
194 /**
195  * __is_kernel_text - checks if the pointer address is located in the
196  *                    .text section
197  *
198  * @addr: address to check
199  *
200  * Returns: true if the address is located in .text, false otherwise.
201  * Note: an internal helper, only check the range of _stext to _etext.
202  */
203 static inline bool __is_kernel_text(unsigned long addr)
204 {
205 	return addr >= (unsigned long)_stext &&
206 	       addr < (unsigned long)_etext;
207 }
208 
209 /**
210  * __is_kernel - checks if the pointer address is located in the kernel range
211  *
212  * @addr: address to check
213  *
214  * Returns: true if the address is located in the kernel range, false otherwise.
215  * Note: an internal helper, check the range of _stext to _end,
216  *       and range from __init_begin to __init_end, which can be outside
217  *       of the _stext to _end range.
218  */
219 static inline bool __is_kernel(unsigned long addr)
220 {
221 	return ((addr >= (unsigned long)_stext &&
222 	         addr < (unsigned long)_end) ||
223 		(addr >= (unsigned long)__init_begin &&
224 		 addr < (unsigned long)__init_end));
225 }
226 
227 #endif /* _ASM_GENERIC_SECTIONS_H_ */
228