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