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 /** 184 * is_kernel_inittext - checks if the pointer address is located in the 185 * .init.text section 186 * 187 * @addr: address to check 188 * 189 * Returns: true if the address is located in .init.text, false otherwise. 190 */ 191 static inline bool is_kernel_inittext(unsigned long addr) 192 { 193 return addr >= (unsigned long)_sinittext && 194 addr < (unsigned long)_einittext; 195 } 196 197 /** 198 * __is_kernel_text - checks if the pointer address is located in the 199 * .text section 200 * 201 * @addr: address to check 202 * 203 * Returns: true if the address is located in .text, false otherwise. 204 * Note: an internal helper, only check the range of _stext to _etext. 205 */ 206 static inline bool __is_kernel_text(unsigned long addr) 207 { 208 return addr >= (unsigned long)_stext && 209 addr < (unsigned long)_etext; 210 } 211 212 /** 213 * __is_kernel - checks if the pointer address is located in the kernel range 214 * 215 * @addr: address to check 216 * 217 * Returns: true if the address is located in the kernel range, false otherwise. 218 * Note: an internal helper, check the range of _stext to _end, 219 * and range from __init_begin to __init_end, which can be outside 220 * of the _stext to _end range. 221 */ 222 static inline bool __is_kernel(unsigned long addr) 223 { 224 return ((addr >= (unsigned long)_stext && 225 addr < (unsigned long)_end) || 226 (addr >= (unsigned long)__init_begin && 227 addr < (unsigned long)__init_end)); 228 } 229 230 #endif /* _ASM_GENERIC_SECTIONS_H_ */ 231