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_ro_after_init, __end_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  *      __irqentry_text_start, __irqentry_text_end
  31  *      __softirqentry_text_start, __softirqentry_text_end
  32  */
  33 extern char _text[], _stext[], _etext[];
  34 extern char _data[], _sdata[], _edata[];
  35 extern char __bss_start[], __bss_stop[];
  36 extern char __init_begin[], __init_end[];
  37 extern char _sinittext[], _einittext[];
  38 extern char __start_ro_after_init[], __end_ro_after_init[];
  39 extern char _end[];
  40 extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
  41 extern char __kprobes_text_start[], __kprobes_text_end[];
  42 extern char __entry_text_start[], __entry_text_end[];
  43 extern char __start_rodata[], __end_rodata[];
  44 extern char __irqentry_text_start[], __irqentry_text_end[];
  45 extern char __softirqentry_text_start[], __softirqentry_text_end[];
  46
  47 /* Start and end of .ctors section - used for constructor calls. */
  48 extern char __ctors_start[], __ctors_end[];
  49
  50 extern __visible const void __nosave_begin, __nosave_end;
  51
  52 /* function descriptor handling (if any).  Override
  53  * in asm/sections.h */
  54 #ifndef dereference_function_descriptor
  55 #define dereference_function_descriptor(p) (p)
  56 #endif
  57
  58 /* random extra sections (if any).  Override
  59  * in asm/sections.h */
  60 #ifndef arch_is_kernel_text
  61 static inline int arch_is_kernel_text(unsigned long addr)
  62 {
  63         return 0;
  64 }
  65 #endif
  66
  67 #ifndef arch_is_kernel_data
  68 static inline int arch_is_kernel_data(unsigned long addr)
  69 {
  70         return 0;
  71 }
  72 #endif
  73
  74 /**
  75  * memory_contains - checks if an object is contained within a memory region
  76  * @begin: virtual address of the beginning of the memory region
  77  * @end: virtual address of the end of the memory region
  78  * @virt: virtual address of the memory object
  79  * @size: size of the memory object
  80  *
  81  * Returns: true if the object specified by @virt and @size is entirely
  82  * contained within the memory region defined by @begin and @end, false
  83  * otherwise.
  84  */
  85 static inline bool memory_contains(void *begin, void *end, void *virt,
  86                                    size_t size)
  87 {
  88         return virt >= begin && virt + size <= end;
  89 }
  90
  91 /**
  92  * memory_intersects - checks if the region occupied by an object intersects
  93  *                     with another memory region
  94  * @begin: virtual address of the beginning of the memory regien
  95  * @end: virtual address of the end of the memory region
  96  * @virt: virtual address of the memory object
  97  * @size: size of the memory object
  98  *
  99  * Returns: true if an object's memory region, specified by @virt and @size,
 100  * intersects with the region specified by @begin and @end, false otherwise.
 101  */
 102 static inline bool memory_intersects(void *begin, void *end, void *virt,
 103                                      size_t size)
 104 {
 105         void *vend = virt + size;
 106
 107         return (virt >= begin && virt < end) || (vend >= begin && vend < end);
 108 }
 109
 110 /**
 111  * init_section_contains - checks if an object is contained within the init
 112  *                         section
 113  * @virt: virtual address of the memory object
 114  * @size: size of the memory object
 115  *
 116  * Returns: true if the object specified by @virt and @size is entirely
 117  * contained within the init section, false otherwise.
 118  */
 119 static inline bool init_section_contains(void *virt, size_t size)
 120 {
 121         return memory_contains(__init_begin, __init_end, virt, size);
 122 }
 123
 124 /**
 125  * init_section_intersects - checks if the region occupied by an object
 126  *                           intersects with the init section
 127  * @virt: virtual address of the memory object
 128  * @size: size of the memory object
 129  *
 130  * Returns: true if an object's memory region, specified by @virt and @size,
 131  * intersects with the init section, false otherwise.
 132  */
 133 static inline bool init_section_intersects(void *virt, size_t size)
 134 {
 135         return memory_intersects(__init_begin, __init_end, virt, size);
 136 }
 137
 138 #endif /* _ASM_GENERIC_SECTIONS_H_ */