include/linux/kallsyms.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Rewritten and vastly simplified by Rusty Russell for in-kernel
   3  * module loader:
   4  *   Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
   5  */
   6 #ifndef _LINUX_KALLSYMS_H
   7 #define _LINUX_KALLSYMS_H
   8
   9 #include <linux/errno.h>
  10 #include <linux/kernel.h>
  11 #include <linux/stddef.h>
  12 #include <linux/mm.h>
  13 #include <linux/module.h>
  14
  15 #include <asm/sections.h>
  16
  17 #define KSYM_NAME_LEN 128
  18 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
  19                          2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
  20
  21 struct module;
  22
  23 static inline int is_kernel_inittext(unsigned long addr)
  24 {
  25         if (addr >= (unsigned long)_sinittext
  26             && addr <= (unsigned long)_einittext)
  27                 return 1;
  28         return 0;
  29 }
  30
  31 static inline int is_kernel_text(unsigned long addr)
  32 {
  33         if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
  34             arch_is_kernel_text(addr))
  35                 return 1;
  36         return in_gate_area_no_mm(addr);
  37 }
  38
  39 static inline int is_kernel(unsigned long addr)
  40 {
  41         if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
  42                 return 1;
  43         return in_gate_area_no_mm(addr);
  44 }
  45
  46 static inline int is_ksym_addr(unsigned long addr)
  47 {
  48         if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
  49                 return is_kernel(addr);
  50
  51         return is_kernel_text(addr) || is_kernel_inittext(addr);
  52 }
  53
  54 static inline void *dereference_symbol_descriptor(void *ptr)
  55 {
  56 #ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
  57         struct module *mod;
  58
  59         ptr = dereference_kernel_function_descriptor(ptr);
  60         if (is_ksym_addr((unsigned long)ptr))
  61                 return ptr;
  62
  63         preempt_disable();
  64         mod = __module_address((unsigned long)ptr);
  65         preempt_enable();
  66
  67         if (mod)
  68                 ptr = dereference_module_function_descriptor(mod, ptr);
  69 #endif
  70         return ptr;
  71 }
  72
  73 #ifdef CONFIG_KALLSYMS
  74 /* Lookup the address for a symbol. Returns 0 if not found. */
  75 unsigned long kallsyms_lookup_name(const char *name);
  76
  77 /* Call a function on each kallsyms symbol in the core kernel */
  78 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
  79                                       unsigned long),
  80                             void *data);
  81
  82 extern int kallsyms_lookup_size_offset(unsigned long addr,
  83                                   unsigned long *symbolsize,
  84                                   unsigned long *offset);
  85
  86 /* Lookup an address.  modname is set to NULL if it's in the kernel. */
  87 const char *kallsyms_lookup(unsigned long addr,
  88                             unsigned long *symbolsize,
  89                             unsigned long *offset,
  90                             char **modname, char *namebuf);
  91
  92 /* Look up a kernel symbol and return it in a text buffer. */
  93 extern int sprint_symbol(char *buffer, unsigned long address);
  94 extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
  95 extern int sprint_backtrace(char *buffer, unsigned long address);
  96
  97 int lookup_symbol_name(unsigned long addr, char *symname);
  98 int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
  99
 100 /* How and when do we show kallsyms values? */
 101 extern int kallsyms_show_value(void);
 102
 103 #else /* !CONFIG_KALLSYMS */
 104
 105 static inline unsigned long kallsyms_lookup_name(const char *name)
 106 {
 107         return 0;
 108 }
 109
 110 static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 111                                                     struct module *,
 112                                                     unsigned long),
 113                                           void *data)
 114 {
 115         return 0;
 116 }
 117
 118 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 119                                               unsigned long *symbolsize,
 120                                               unsigned long *offset)
 121 {
 122         return 0;
 123 }
 124
 125 static inline const char *kallsyms_lookup(unsigned long addr,
 126                                           unsigned long *symbolsize,
 127                                           unsigned long *offset,
 128                                           char **modname, char *namebuf)
 129 {
 130         return NULL;
 131 }
 132
 133 static inline int sprint_symbol(char *buffer, unsigned long addr)
 134 {
 135         *buffer = '\0';
 136         return 0;
 137 }
 138
 139 static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 140 {
 141         *buffer = '\0';
 142         return 0;
 143 }
 144
 145 static inline int sprint_backtrace(char *buffer, unsigned long addr)
 146 {
 147         *buffer = '\0';
 148         return 0;
 149 }
 150
 151 static inline int lookup_symbol_name(unsigned long addr, char *symname)
 152 {
 153         return -ERANGE;
 154 }
 155
 156 static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
 157 {
 158         return -ERANGE;
 159 }
 160
 161 static inline int kallsyms_show_value(void)
 162 {
 163         return false;
 164 }
 165
 166 #endif /*CONFIG_KALLSYMS*/
 167
 168 static inline void print_ip_sym(unsigned long ip)
 169 {
 170         printk("[<%px>] %pS\n", (void *) ip, (void *) ip);
 171 }
 172
 173 #endif /*_LINUX_KALLSYMS_H*/