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 #else 64 #define dereference_function_descriptor(p) ((void *)(p)) 65 #define dereference_kernel_function_descriptor(p) ((void *)(p)) 66 #endif 67 68 static inline bool have_function_descriptors(void) 69 { 70 return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS); 71 } 72 73 /** 74 * memory_contains - checks if an object is contained within a memory region 75 * @begin: virtual address of the beginning of the memory region 76 * @end: virtual address of the end of the memory region 77 * @virt: virtual address of the memory object 78 * @size: size of the memory object 79 * 80 * Returns: true if the object specified by @virt and @size is entirely 81 * contained within the memory region defined by @begin and @end, false 82 * otherwise. 83 */ 84 static inline bool memory_contains(void *begin, void *end, void *virt, 85 size_t size) 86 { 87 return virt >= begin && virt + size <= end; 88 } 89 90 /** 91 * memory_intersects - checks if the region occupied by an object intersects 92 * with another memory region 93 * @begin: virtual address of the beginning of the memory regien 94 * @end: virtual address of the end of the memory region 95 * @virt: virtual address of the memory object 96 * @size: size of the memory object 97 * 98 * Returns: true if an object's memory region, specified by @virt and @size, 99 * intersects with the region specified by @begin and @end, false otherwise. 100 */ 101 static inline bool memory_intersects(void *begin, void *end, void *virt, 102 size_t size) 103 { 104 void *vend = virt + size; 105 106 return (virt >= begin && virt < end) || (vend >= begin && vend < end); 107 } 108 109 /** 110 * init_section_contains - checks if an object is contained within the init 111 * section 112 * @virt: virtual address of the memory object 113 * @size: size of the memory object 114 * 115 * Returns: true if the object specified by @virt and @size is entirely 116 * contained within the init section, false otherwise. 117 */ 118 static inline bool init_section_contains(void *virt, size_t size) 119 { 120 return memory_contains(__init_begin, __init_end, virt, size); 121 } 122 123 /** 124 * init_section_intersects - checks if the region occupied by an object 125 * intersects with the init section 126 * @virt: virtual address of the memory object 127 * @size: size of the memory object 128 * 129 * Returns: true if an object's memory region, specified by @virt and @size, 130 * intersects with the init section, false otherwise. 131 */ 132 static inline bool init_section_intersects(void *virt, size_t size) 133 { 134 return memory_intersects(__init_begin, __init_end, virt, size); 135 } 136 137 /** 138 * is_kernel_core_data - checks if the pointer address is located in the 139 * .data or .bss section 140 * 141 * @addr: address to check 142 * 143 * Returns: true if the address is located in .data or .bss, false otherwise. 144 * Note: On some archs it may return true for core RODATA, and false 145 * for others. But will always be true for core RW data. 146 */ 147 static inline bool is_kernel_core_data(unsigned long addr) 148 { 149 if (addr >= (unsigned long)_sdata && addr < (unsigned long)_edata) 150 return true; 151 152 if (addr >= (unsigned long)__bss_start && 153 addr < (unsigned long)__bss_stop) 154 return true; 155 156 return false; 157 } 158 159 /** 160 * is_kernel_rodata - checks if the pointer address is located in the 161 * .rodata section 162 * 163 * @addr: address to check 164 * 165 * Returns: true if the address is located in .rodata, false otherwise. 166 */ 167 static inline bool is_kernel_rodata(unsigned long addr) 168 { 169 return addr >= (unsigned long)__start_rodata && 170 addr < (unsigned long)__end_rodata; 171 } 172 173 /** 174 * is_kernel_inittext - checks if the pointer address is located in the 175 * .init.text section 176 * 177 * @addr: address to check 178 * 179 * Returns: true if the address is located in .init.text, false otherwise. 180 */ 181 static inline bool is_kernel_inittext(unsigned long addr) 182 { 183 return addr >= (unsigned long)_sinittext && 184 addr < (unsigned long)_einittext; 185 } 186 187 /** 188 * __is_kernel_text - checks if the pointer address is located in the 189 * .text section 190 * 191 * @addr: address to check 192 * 193 * Returns: true if the address is located in .text, false otherwise. 194 * Note: an internal helper, only check the range of _stext to _etext. 195 */ 196 static inline bool __is_kernel_text(unsigned long addr) 197 { 198 return addr >= (unsigned long)_stext && 199 addr < (unsigned long)_etext; 200 } 201 202 /** 203 * __is_kernel - checks if the pointer address is located in the kernel range 204 * 205 * @addr: address to check 206 * 207 * Returns: true if the address is located in the kernel range, false otherwise. 208 * Note: an internal helper, check the range of _stext to _end, 209 * and range from __init_begin to __init_end, which can be outside 210 * of the _stext to _end range. 211 */ 212 static inline bool __is_kernel(unsigned long addr) 213 { 214 return ((addr >= (unsigned long)_stext && 215 addr < (unsigned long)_end) || 216 (addr >= (unsigned long)__init_begin && 217 addr < (unsigned long)__init_end)); 218 } 219 220 #endif /* _ASM_GENERIC_SECTIONS_H_ */ 221