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 /* How and when do we show kallsyms values? */
  69 extern bool kallsyms_show_value(const struct cred *cred);
  70
  71 #ifdef CONFIG_KALLSYMS
  72 unsigned long kallsyms_sym_address(int idx);
  73 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
  74                             void *data);
  75 int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
  76                                   const char *name, void *data);
  77
  78 /* Lookup the address for a symbol. Returns 0 if not found. */
  79 unsigned long kallsyms_lookup_name(const char *name);
  80
  81 extern int kallsyms_lookup_size_offset(unsigned long addr,
  82                                   unsigned long *symbolsize,
  83                                   unsigned long *offset);
  84
  85 /* Lookup an address.  modname is set to NULL if it's in the kernel. */
  86 const char *kallsyms_lookup(unsigned long addr,
  87                             unsigned long *symbolsize,
  88                             unsigned long *offset,
  89                             char **modname, char *namebuf);
  90
  91 /* Look up a kernel symbol and return it in a text buffer. */
  92 extern int sprint_symbol(char *buffer, unsigned long address);
  93 extern int sprint_symbol_build_id(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 extern int sprint_backtrace_build_id(char *buffer, unsigned long address);
  97
  98 int lookup_symbol_name(unsigned long addr, char *symname);
  99
 100 #else /* !CONFIG_KALLSYMS */
 101
 102 static inline unsigned long kallsyms_lookup_name(const char *name)
 103 {
 104         return 0;
 105 }
 106
 107 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 108                                               unsigned long *symbolsize,
 109                                               unsigned long *offset)
 110 {
 111         return 0;
 112 }
 113
 114 static inline const char *kallsyms_lookup(unsigned long addr,
 115                                           unsigned long *symbolsize,
 116                                           unsigned long *offset,
 117                                           char **modname, char *namebuf)
 118 {
 119         return NULL;
 120 }
 121
 122 static inline int sprint_symbol(char *buffer, unsigned long addr)
 123 {
 124         *buffer = '\0';
 125         return 0;
 126 }
 127
 128 static inline int sprint_symbol_build_id(char *buffer, unsigned long address)
 129 {
 130         *buffer = '\0';
 131         return 0;
 132 }
 133
 134 static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 135 {
 136         *buffer = '\0';
 137         return 0;
 138 }
 139
 140 static inline int sprint_backtrace(char *buffer, unsigned long addr)
 141 {
 142         *buffer = '\0';
 143         return 0;
 144 }
 145
 146 static inline int sprint_backtrace_build_id(char *buffer, unsigned long addr)
 147 {
 148         *buffer = '\0';
 149         return 0;
 150 }
 151
 152 static inline int lookup_symbol_name(unsigned long addr, char *symname)
 153 {
 154         return -ERANGE;
 155 }
 156
 157 static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
 158                                           void *data)
 159 {
 160         return -EOPNOTSUPP;
 161 }
 162
 163 static inline int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
 164                                                 const char *name, void *data)
 165 {
 166         return -EOPNOTSUPP;
 167 }
 168 #endif /*CONFIG_KALLSYMS*/
 169
 170 static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 171 {
 172         printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 173 }
 174
 175 #endif /*_LINUX_KALLSYMS_H*/