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 #ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
  63 void *dereference_function_descriptor(void *ptr);
  64 void *dereference_kernel_function_descriptor(void *ptr);
  65 #else
  66 #define dereference_function_descriptor(p) ((void *)(p))
  67 #define dereference_kernel_function_descriptor(p) ((void *)(p))
  68
  69 /* An address is simply the address of the function. */
  70 typedef struct {
  71         unsigned long addr;
  72 } func_desc_t;
  73 #endif
  74
  75 static inline bool have_function_descriptors(void)
  76 {
  77         return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS);
  78 }
  79
  80 /**
  81  * memory_contains - checks if an object is contained within a memory region
  82  * @begin: virtual address of the beginning of the memory region
  83  * @end: virtual address of the end of the memory region
  84  * @virt: virtual address of the memory object
  85  * @size: size of the memory object
  86  *
  87  * Returns: true if the object specified by @virt and @size is entirely
  88  * contained within the memory region defined by @begin and @end, false
  89  * otherwise.
  90  */
  91 static inline bool memory_contains(void *begin, void *end, void *virt,
  92                                    size_t size)
  93 {
  94         return virt >= begin && virt + size <= end;
  95 }
  96
  97 /**
  98  * memory_intersects - checks if the region occupied by an object intersects
  99  *                     with another memory region
 100  * @begin: virtual address of the beginning of the memory region
 101  * @end: virtual address of the end of the memory region
 102  * @virt: virtual address of the memory object
 103  * @size: size of the memory object
 104  *
 105  * Returns: true if an object's memory region, specified by @virt and @size,
 106  * intersects with the region specified by @begin and @end, false otherwise.
 107  */
 108 static inline bool memory_intersects(void *begin, void *end, void *virt,
 109                                      size_t size)
 110 {
 111         void *vend = virt + size;
 112
 113         if (virt < end && vend > begin)
 114                 return true;
 115
 116         return false;
 117 }
 118
 119 /**
 120  * init_section_contains - checks if an object is contained within the init
 121  *                         section
 122  * @virt: virtual address of the memory object
 123  * @size: size of the memory object
 124  *
 125  * Returns: true if the object specified by @virt and @size is entirely
 126  * contained within the init section, false otherwise.
 127  */
 128 static inline bool init_section_contains(void *virt, size_t size)
 129 {
 130         return memory_contains(__init_begin, __init_end, virt, size);
 131 }
 132
 133 /**
 134  * init_section_intersects - checks if the region occupied by an object
 135  *                           intersects with the init section
 136  * @virt: virtual address of the memory object
 137  * @size: size of the memory object
 138  *
 139  * Returns: true if an object's memory region, specified by @virt and @size,
 140  * intersects with the init section, false otherwise.
 141  */
 142 static inline bool init_section_intersects(void *virt, size_t size)
 143 {
 144         return memory_intersects(__init_begin, __init_end, virt, size);
 145 }
 146
 147 /**
 148  * is_kernel_core_data - checks if the pointer address is located in the
 149  *                       .data or .bss section
 150  *
 151  * @addr: address to check
 152  *
 153  * Returns: true if the address is located in .data or .bss, false otherwise.
 154  * Note: On some archs it may return true for core RODATA, and false
 155  *       for others. But will always be true for core RW data.
 156  */
 157 static inline bool is_kernel_core_data(unsigned long addr)
 158 {
 159         if (addr >= (unsigned long)_sdata && addr < (unsigned long)_edata)
 160                 return true;
 161
 162         if (addr >= (unsigned long)__bss_start &&
 163             addr < (unsigned long)__bss_stop)
 164                 return true;
 165
 166         return false;
 167 }
 168
 169 /**
 170  * is_kernel_rodata - checks if the pointer address is located in the
 171  *                    .rodata section
 172  *
 173  * @addr: address to check
 174  *
 175  * Returns: true if the address is located in .rodata, false otherwise.
 176  */
 177 static inline bool is_kernel_rodata(unsigned long addr)
 178 {
 179         return addr >= (unsigned long)__start_rodata &&
 180                addr < (unsigned long)__end_rodata;
 181 }
 182
 183 static inline bool is_kernel_ro_after_init(unsigned long addr)
 184 {
 185         return addr >= (unsigned long)__start_ro_after_init &&
 186                addr < (unsigned long)__end_ro_after_init;
 187 }
 188 /**
 189  * is_kernel_inittext - checks if the pointer address is located in the
 190  *                      .init.text section
 191  *
 192  * @addr: address to check
 193  *
 194  * Returns: true if the address is located in .init.text, false otherwise.
 195  */
 196 static inline bool is_kernel_inittext(unsigned long addr)
 197 {
 198         return addr >= (unsigned long)_sinittext &&
 199                addr < (unsigned long)_einittext;
 200 }
 201
 202 /**
 203  * __is_kernel_text - checks if the pointer address is located in the
 204  *                    .text section
 205  *
 206  * @addr: address to check
 207  *
 208  * Returns: true if the address is located in .text, false otherwise.
 209  * Note: an internal helper, only check the range of _stext to _etext.
 210  */
 211 static inline bool __is_kernel_text(unsigned long addr)
 212 {
 213         return addr >= (unsigned long)_stext &&
 214                addr < (unsigned long)_etext;
 215 }
 216
 217 /**
 218  * __is_kernel - checks if the pointer address is located in the kernel range
 219  *
 220  * @addr: address to check
 221  *
 222  * Returns: true if the address is located in the kernel range, false otherwise.
 223  * Note: an internal helper, check the range of _stext to _end,
 224  *       and range from __init_begin to __init_end, which can be outside
 225  *       of the _stext to _end range.
 226  */
 227 static inline bool __is_kernel(unsigned long addr)
 228 {
 229         return ((addr >= (unsigned long)_stext &&
 230                  addr < (unsigned long)_end) ||
 231                 (addr >= (unsigned long)__init_begin &&
 232                  addr < (unsigned long)__init_end));
 233 }
 234
 235 #endif /* _ASM_GENERIC_SECTIONS_H_ */