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  * [__init_begin, __init_end]: contains .init.* sections, but .init.text.*
  18  *                   may be out of this range on some architectures.
  19  * [_sinittext, _einittext]: contains .init.text.* sections
  20  * [__bss_start, __bss_stop]: contains BSS sections
  21  *
  22  * Following global variables are optional and may be unavailable on some
  23  * architectures and/or kernel configurations.
  24  *      _text, _data
  25  *      __kprobes_text_start, __kprobes_text_end
  26  *      __entry_text_start, __entry_text_end
  27  *      __ctors_start, __ctors_end
  28  */
  29 extern char _text[], _stext[], _etext[];
  30 extern char _data[], _sdata[], _edata[];
  31 extern char __bss_start[], __bss_stop[];
  32 extern char __init_begin[], __init_end[];
  33 extern char _sinittext[], _einittext[];
  34 extern char _end[];
  35 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
  36 extern char __kprobes_text_start[], __kprobes_text_end[];
  37 extern char __entry_text_start[], __entry_text_end[];
  38 extern char __start_rodata[], __end_rodata[];
  39
  40 /* Start and end of .ctors section - used for constructor calls. */
  41 extern char __ctors_start[], __ctors_end[];
  42
  43 extern __visible const void __nosave_begin, __nosave_end;
  44
  45 /* function descriptor handling (if any).  Override
  46  * in asm/sections.h */
  47 #ifndef dereference_function_descriptor
  48 #define dereference_function_descriptor(p) (p)
  49 #endif
  50
  51 /* random extra sections (if any).  Override
  52  * in asm/sections.h */
  53 #ifndef arch_is_kernel_text
  54 static inline int arch_is_kernel_text(unsigned long addr)
  55 {
  56         return 0;
  57 }
  58 #endif
  59
  60 #ifndef arch_is_kernel_data
  61 static inline int arch_is_kernel_data(unsigned long addr)
  62 {
  63         return 0;
  64 }
  65 #endif
  66
  67 /**
  68  * memory_contains - checks if an object is contained within a memory region
  69  * @begin: virtual address of the beginning of the memory region
  70  * @end: virtual address of the end of the memory region
  71  * @virt: virtual address of the memory object
  72  * @size: size of the memory object
  73  *
  74  * Returns: true if the object specified by @virt and @size is entirely
  75  * contained within the memory region defined by @begin and @end, false
  76  * otherwise.
  77  */
  78 static inline bool memory_contains(void *begin, void *end, void *virt,
  79                                    size_t size)
  80 {
  81         return virt >= begin && virt + size <= end;
  82 }
  83
  84 /**
  85  * memory_intersects - checks if the region occupied by an object intersects
  86  *                     with another memory region
  87  * @begin: virtual address of the beginning of the memory regien
  88  * @end: virtual address of the end of the memory region
  89  * @virt: virtual address of the memory object
  90  * @size: size of the memory object
  91  *
  92  * Returns: true if an object's memory region, specified by @virt and @size,
  93  * intersects with the region specified by @begin and @end, false otherwise.
  94  */
  95 static inline bool memory_intersects(void *begin, void *end, void *virt,
  96                                      size_t size)
  97 {
  98         void *vend = virt + size;
  99
 100         return (virt >= begin && virt < end) || (vend >= begin && vend < end);
 101 }
 102
 103 /**
 104  * init_section_contains - checks if an object is contained within the init
 105  *                         section
 106  * @virt: virtual address of the memory object
 107  * @size: size of the memory object
 108  *
 109  * Returns: true if the object specified by @virt and @size is entirely
 110  * contained within the init section, false otherwise.
 111  */
 112 static inline bool init_section_contains(void *virt, size_t size)
 113 {
 114         return memory_contains(__init_begin, __init_end, virt, size);
 115 }
 116
 117 /**
 118  * init_section_intersects - checks if the region occupied by an object
 119  *                           intersects with the init section
 120  * @virt: virtual address of the memory object
 121  * @size: size of the memory object
 122  *
 123  * Returns: true if an object's memory region, specified by @virt and @size,
 124  * intersects with the init section, false otherwise.
 125  */
 126 static inline bool init_section_intersects(void *virt, size_t size)
 127 {
 128         return memory_intersects(__init_begin, __init_end, virt, size);
 129 }
 130
 131 #endif /* _ASM_GENERIC_SECTIONS_H_ */