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  *      __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_ */