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/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 128
  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
  24struct cred;
  25struct module;
  26
  27static 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
  34static 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
  41static 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
  49static 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
  69int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
  70                                      unsigned long),
  71                            void *data);
  72
  73/* Lookup the address for a symbol. Returns 0 if not found. */
  74unsigned long kallsyms_lookup_name(const char *name);
  75
  76extern int kallsyms_lookup_size_offset(unsigned long addr,
  77                                  unsigned long *symbolsize,
  78                                  unsigned long *offset);
  79
  80/* Lookup an address.  modname is set to NULL if it's in the kernel. */
  81const char *kallsyms_lookup(unsigned long addr,
  82                            unsigned long *symbolsize,
  83                            unsigned long *offset,
  84                            char **modname, char *namebuf);
  85
  86/* Look up a kernel symbol and return it in a text buffer. */
  87extern int sprint_symbol(char *buffer, unsigned long address);
  88extern int sprint_symbol_build_id(char *buffer, unsigned long address);
  89extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
  90extern int sprint_backtrace(char *buffer, unsigned long address);
  91extern int sprint_backtrace_build_id(char *buffer, unsigned long address);
  92
  93int lookup_symbol_name(unsigned long addr, char *symname);
  94int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
  95
  96/* How and when do we show kallsyms values? */
  97extern bool kallsyms_show_value(const struct cred *cred);
  98
  99#else /* !CONFIG_KALLSYMS */
 100
 101static inline unsigned long kallsyms_lookup_name(const char *name)
 102{
 103        return 0;
 104}
 105
 106static inline int kallsyms_lookup_size_offset(unsigned long addr,
 107                                              unsigned long *symbolsize,
 108                                              unsigned long *offset)
 109{
 110        return 0;
 111}
 112
 113static inline const char *kallsyms_lookup(unsigned long addr,
 114                                          unsigned long *symbolsize,
 115                                          unsigned long *offset,
 116                                          char **modname, char *namebuf)
 117{
 118        return NULL;
 119}
 120
 121static inline int sprint_symbol(char *buffer, unsigned long addr)
 122{
 123        *buffer = '\0';
 124        return 0;
 125}
 126
 127static inline int sprint_symbol_build_id(char *buffer, unsigned long address)
 128{
 129        *buffer = '\0';
 130        return 0;
 131}
 132
 133static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 134{
 135        *buffer = '\0';
 136        return 0;
 137}
 138
 139static inline int sprint_backtrace(char *buffer, unsigned long addr)
 140{
 141        *buffer = '\0';
 142        return 0;
 143}
 144
 145static inline int sprint_backtrace_build_id(char *buffer, unsigned long addr)
 146{
 147        *buffer = '\0';
 148        return 0;
 149}
 150
 151static inline int lookup_symbol_name(unsigned long addr, char *symname)
 152{
 153        return -ERANGE;
 154}
 155
 156static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
 157{
 158        return -ERANGE;
 159}
 160
 161static inline bool kallsyms_show_value(const struct cred *cred)
 162{
 163        return false;
 164}
 165
 166static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 167                                          unsigned long), void *data)
 168{
 169        return -EOPNOTSUPP;
 170}
 171#endif /*CONFIG_KALLSYMS*/
 172
 173static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 174{
 175        printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 176}
 177
 178#endif /*_LINUX_KALLSYMS_H*/
 179