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/buildid.h>
  11 #include <linux/kernel.h>
  12 #include <linux/stddef.h>
  13 #include <linux/mm.h>
  14 #include <linux/module.h>
  15
  16 #include <asm/sections.h>
  17
  18 #define KSYM_NAME_LEN 512
  19 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
  20                         (KSYM_NAME_LEN - 1) + \
  21                         2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
  22                         (BUILD_ID_SIZE_MAX * 2) + 1)
  23
  24 struct cred;
  25 struct module;
  26
  27 static inline int is_kernel_text(unsigned long addr)
  28 {
  29         if (__is_kernel_text(addr))
  30                 return 1;
  31         return in_gate_area_no_mm(addr);
  32 }
  33
  34 static inline int is_kernel(unsigned long addr)
  35 {
  36         if (__is_kernel(addr))
  37                 return 1;
  38         return in_gate_area_no_mm(addr);
  39 }
  40
  41 static inline int is_ksym_addr(unsigned long addr)
  42 {
  43         if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
  44                 return is_kernel(addr);
  45
  46         return is_kernel_text(addr) || is_kernel_inittext(addr);
  47 }
  48
  49 static inline void *dereference_symbol_descriptor(void *ptr)
  50 {
  51 #ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
  52         struct module *mod;
  53
  54         ptr = dereference_kernel_function_descriptor(ptr);
  55         if (is_ksym_addr((unsigned long)ptr))
  56                 return ptr;
  57
  58         preempt_disable();
  59         mod = __module_address((unsigned long)ptr);
  60         preempt_enable();
  61
  62         if (mod)
  63                 ptr = dereference_module_function_descriptor(mod, ptr);
  64 #endif
  65         return ptr;
  66 }
  67
  68 #ifdef CONFIG_KALLSYMS
  69 unsigned long kallsyms_sym_address(int idx);
  70 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
  71                                       unsigned long),
  72                             void *data);
  73 int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
  74                                   const char *name, void *data);
  75
  76 /* Lookup the address for a symbol. Returns 0 if not found. */
  77 unsigned long kallsyms_lookup_name(const char *name);
  78
  79 extern int kallsyms_lookup_size_offset(unsigned long addr,
  80                                   unsigned long *symbolsize,
  81                                   unsigned long *offset);
  82
  83 /* Lookup an address.  modname is set to NULL if it's in the kernel. */
  84 const char *kallsyms_lookup(unsigned long addr,
  85                             unsigned long *symbolsize,
  86                             unsigned long *offset,
  87                             char **modname, char *namebuf);
  88
  89 /* Look up a kernel symbol and return it in a text buffer. */
  90 extern int sprint_symbol(char *buffer, unsigned long address);
  91 extern int sprint_symbol_build_id(char *buffer, unsigned long address);
  92 extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
  93 extern int sprint_backtrace(char *buffer, unsigned long address);
  94 extern int sprint_backtrace_build_id(char *buffer, unsigned long address);
  95
  96 int lookup_symbol_name(unsigned long addr, char *symname);
  97 int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
  98
  99 /* How and when do we show kallsyms values? */
 100 extern bool kallsyms_show_value(const struct cred *cred);
 101
 102 #else /* !CONFIG_KALLSYMS */
 103
 104 static inline unsigned long kallsyms_lookup_name(const char *name)
 105 {
 106         return 0;
 107 }
 108
 109 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 110                                               unsigned long *symbolsize,
 111                                               unsigned long *offset)
 112 {
 113         return 0;
 114 }
 115
 116 static inline const char *kallsyms_lookup(unsigned long addr,
 117                                           unsigned long *symbolsize,
 118                                           unsigned long *offset,
 119                                           char **modname, char *namebuf)
 120 {
 121         return NULL;
 122 }
 123
 124 static inline int sprint_symbol(char *buffer, unsigned long addr)
 125 {
 126         *buffer = '\0';
 127         return 0;
 128 }
 129
 130 static inline int sprint_symbol_build_id(char *buffer, unsigned long address)
 131 {
 132         *buffer = '\0';
 133         return 0;
 134 }
 135
 136 static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 137 {
 138         *buffer = '\0';
 139         return 0;
 140 }
 141
 142 static inline int sprint_backtrace(char *buffer, unsigned long addr)
 143 {
 144         *buffer = '\0';
 145         return 0;
 146 }
 147
 148 static inline int sprint_backtrace_build_id(char *buffer, unsigned long addr)
 149 {
 150         *buffer = '\0';
 151         return 0;
 152 }
 153
 154 static inline int lookup_symbol_name(unsigned long addr, char *symname)
 155 {
 156         return -ERANGE;
 157 }
 158
 159 static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
 160 {
 161         return -ERANGE;
 162 }
 163
 164 static inline bool kallsyms_show_value(const struct cred *cred)
 165 {
 166         return false;
 167 }
 168
 169 static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 170                                           unsigned long), void *data)
 171 {
 172         return -EOPNOTSUPP;
 173 }
 174
 175 static inline int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
 176                                                 const char *name, void *data)
 177 {
 178         return -EOPNOTSUPP;
 179 }
 180 #endif /*CONFIG_KALLSYMS*/
 181
 182 static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 183 {
 184         printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 185 }
 186
 187 #endif /*_LINUX_KALLSYMS_H*/