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 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 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 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 */ 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 */ 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 */ 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 */ 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 */ 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