include/asm-generic/sections.h

   1 #ifndef _ASM_GENERIC_SECTIONS_H_
   2 #define _ASM_GENERIC_SECTIONS_H_
   3
   4 /* References to section boundaries */
   5
   6 #include <linux/compiler.h>
   7 #include <linux/types.h>
   8
   9 /*
  10  * Usage guidelines:
  11  * _text, _data: architecture specific, don't use them in arch-independent code
  12  * [_stext, _etext]: contains .text.* sections, may also contain .rodata.*
  13  *                   and/or .init.* sections
  14  * [_sdata, _edata]: contains .data.* sections, may also contain .rodata.*
  15  *                   and/or .init.* sections.
  16  * [__start_rodata, __end_rodata]: contains .rodata.* sections
  17  * [__start_data_ro_after_init, __end_data_ro_after_init]:
  18  *                   contains data.ro_after_init section
  19  * [__init_begin, __init_end]: contains .init.* sections, but .init.text.*
  20  *                   may be out of this range on some architectures.
  21  * [_sinittext, _einittext]: contains .init.text.* sections
  22  * [__bss_start, __bss_stop]: contains BSS sections
  23  *
  24  * Following global variables are optional and may be unavailable on some
  25  * architectures and/or kernel configurations.
  26  *      _text, _data
  27  *      __kprobes_text_start, __kprobes_text_end
  28  *      __entry_text_start, __entry_text_end
  29  *      __ctors_start, __ctors_end
  30  */
  31 extern char _text[], _stext[], _etext[];
  32 extern char _data[], _sdata[], _edata[];
  33 extern char __bss_start[], __bss_stop[];
  34 extern char __init_begin[], __init_end[];
  35 extern char _sinittext[], _einittext[];
  36 extern char __start_data_ro_after_init[], __end_data_ro_after_init[];
  37 extern char _end[];
  38 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
  39 extern char __kprobes_text_start[], __kprobes_text_end[];
  40 extern char __entry_text_start[], __entry_text_end[];
  41 extern char __start_rodata[], __end_rodata[];
  42
  43 /* Start and end of .ctors section - used for constructor calls. */
  44 extern char __ctors_start[], __ctors_end[];
  45
  46 extern __visible const void __nosave_begin, __nosave_end;
  47
  48 /* function descriptor handling (if any).  Override
  49  * in asm/sections.h */
  50 #ifndef dereference_function_descriptor
  51 #define dereference_function_descriptor(p) (p)
  52 #endif
  53
  54 /* random extra sections (if any).  Override
  55  * in asm/sections.h */
  56 #ifndef arch_is_kernel_text
  57 static inline int arch_is_kernel_text(unsigned long addr)
  58 {
  59         return 0;
  60 }
  61 #endif
  62
  63 #ifndef arch_is_kernel_data
  64 static inline int arch_is_kernel_data(unsigned long addr)
  65 {
  66         return 0;
  67 }
  68 #endif
  69
  70 /**
  71  * memory_contains - checks if an object is contained within a memory region
  72  * @begin: virtual address of the beginning of the memory region
  73  * @end: virtual address of the end of the memory region
  74  * @virt: virtual address of the memory object
  75  * @size: size of the memory object
  76  *
  77  * Returns: true if the object specified by @virt and @size is entirely
  78  * contained within the memory region defined by @begin and @end, false
  79  * otherwise.
  80  */
  81 static inline bool memory_contains(void *begin, void *end, void *virt,
  82                                    size_t size)
  83 {
  84         return virt >= begin && virt + size <= end;
  85 }
  86
  87 /**
  88  * memory_intersects - checks if the region occupied by an object intersects
  89  *                     with another memory region
  90  * @begin: virtual address of the beginning of the memory regien
  91  * @end: virtual address of the end of the memory region
  92  * @virt: virtual address of the memory object
  93  * @size: size of the memory object
  94  *
  95  * Returns: true if an object's memory region, specified by @virt and @size,
  96  * intersects with the region specified by @begin and @end, false otherwise.
  97  */
  98 static inline bool memory_intersects(void *begin, void *end, void *virt,
  99                                      size_t size)
 100 {
 101         void *vend = virt + size;
 102
 103         return (virt >= begin && virt < end) || (vend >= begin && vend < end);
 104 }
 105
 106 /**
 107  * init_section_contains - checks if an object is contained within the init
 108  *                         section
 109  * @virt: virtual address of the memory object
 110  * @size: size of the memory object
 111  *
 112  * Returns: true if the object specified by @virt and @size is entirely
 113  * contained within the init section, false otherwise.
 114  */
 115 static inline bool init_section_contains(void *virt, size_t size)
 116 {
 117         return memory_contains(__init_begin, __init_end, virt, size);
 118 }
 119
 120 /**
 121  * init_section_intersects - checks if the region occupied by an object
 122  *                           intersects with the init section
 123  * @virt: virtual address of the memory object
 124  * @size: size of the memory object
 125  *
 126  * Returns: true if an object's memory region, specified by @virt and @size,
 127  * intersects with the init section, false otherwise.
 128  */
 129 static inline bool init_section_intersects(void *virt, size_t size)
 130 {
 131         return memory_intersects(__init_begin, __init_end, virt, size);
 132 }
 133
 134 #endif /* _ASM_GENERIC_SECTIONS_H_ */