include/asm-generic/sections.h

   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  */
  34 extern char _text[], _stext[], _etext[];
  35 extern char _data[], _sdata[], _edata[];
  36 extern char __bss_start[], __bss_stop[];
  37 extern char __init_begin[], __init_end[];
  38 extern char _sinittext[], _einittext[];
  39 extern char __start_ro_after_init[], __end_ro_after_init[];
  40 extern char _end[];
  41 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
  42 extern char __kprobes_text_start[], __kprobes_text_end[];
  43 extern char __entry_text_start[], __entry_text_end[];
  44 extern char __start_rodata[], __end_rodata[];
  45 extern char __irqentry_text_start[], __irqentry_text_end[];
  46 extern char __softirqentry_text_start[], __softirqentry_text_end[];
  47 extern char __start_once[], __end_once[];
  48
  49 /* Start and end of .ctors section - used for constructor calls. */
  50 extern char __ctors_start[], __ctors_end[];
  51
  52 extern __visible const void __nosave_begin, __nosave_end;
  53
  54 /* function descriptor handling (if any).  Override
  55  * in asm/sections.h */
  56 #ifndef dereference_function_descriptor
  57 #define dereference_function_descriptor(p) (p)
  58 #endif
  59
  60 /* random extra sections (if any).  Override
  61  * in asm/sections.h */
  62 #ifndef arch_is_kernel_text
  63 static inline int arch_is_kernel_text(unsigned long addr)
  64 {
  65         return 0;
  66 }
  67 #endif
  68
  69 #ifndef arch_is_kernel_data
  70 static inline int arch_is_kernel_data(unsigned long addr)
  71 {
  72         return 0;
  73 }
  74 #endif
  75
  76 /**
  77  * memory_contains - checks if an object is contained within a memory region
  78  * @begin: virtual address of the beginning of the memory region
  79  * @end: virtual address of the end of the memory region
  80  * @virt: virtual address of the memory object
  81  * @size: size of the memory object
  82  *
  83  * Returns: true if the object specified by @virt and @size is entirely
  84  * contained within the memory region defined by @begin and @end, false
  85  * otherwise.
  86  */
  87 static inline bool memory_contains(void *begin, void *end, void *virt,
  88                                    size_t size)
  89 {
  90         return virt >= begin && virt + size <= end;
  91 }
  92
  93 /**
  94  * memory_intersects - checks if the region occupied by an object intersects
  95  *                     with another memory region
  96  * @begin: virtual address of the beginning of the memory regien
  97  * @end: virtual address of the end of the memory region
  98  * @virt: virtual address of the memory object
  99  * @size: size of the memory object
 100  *
 101  * Returns: true if an object's memory region, specified by @virt and @size,
 102  * intersects with the region specified by @begin and @end, false otherwise.
 103  */
 104 static inline bool memory_intersects(void *begin, void *end, void *virt,
 105                                      size_t size)
 106 {
 107         void *vend = virt + size;
 108
 109         return (virt >= begin && virt < end) || (vend >= begin && vend < end);
 110 }
 111
 112 /**
 113  * init_section_contains - checks if an object is contained within the init
 114  *                         section
 115  * @virt: virtual address of the memory object
 116  * @size: size of the memory object
 117  *
 118  * Returns: true if the object specified by @virt and @size is entirely
 119  * contained within the init section, false otherwise.
 120  */
 121 static inline bool init_section_contains(void *virt, size_t size)
 122 {
 123         return memory_contains(__init_begin, __init_end, virt, size);
 124 }
 125
 126 /**
 127  * init_section_intersects - checks if the region occupied by an object
 128  *                           intersects with the init section
 129  * @virt: virtual address of the memory object
 130  * @size: size of the memory object
 131  *
 132  * Returns: true if an object's memory region, specified by @virt and @size,
 133  * intersects with the init section, false otherwise.
 134  */
 135 static inline bool init_section_intersects(void *virt, size_t size)
 136 {
 137         return memory_intersects(__init_begin, __init_end, virt, size);
 138 }
 139
 140 #endif /* _ASM_GENERIC_SECTIONS_H_ */