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 module;
  22
  23static 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
  31static 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
  39static 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
  46static 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
  54static 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. */
  75unsigned long kallsyms_lookup_name(const char *name);
  76
  77/* Call a function on each kallsyms symbol in the core kernel */
  78int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
  79                                      unsigned long),
  80                            void *data);
  81
  82extern 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. */
  87const 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. */
  93extern int sprint_symbol(char *buffer, unsigned long address);
  94extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
  95extern int sprint_backtrace(char *buffer, unsigned long address);
  96
  97int lookup_symbol_name(unsigned long addr, char *symname);
  98int 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? */
 101extern int kallsyms_show_value(void);
 102
 103#else /* !CONFIG_KALLSYMS */
 104
 105static inline unsigned long kallsyms_lookup_name(const char *name)
 106{
 107        return 0;
 108}
 109
 110static 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
 118static inline int kallsyms_lookup_size_offset(unsigned long addr,
 119                                              unsigned long *symbolsize,
 120                                              unsigned long *offset)
 121{
 122        return 0;
 123}
 124
 125static 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
 133static inline int sprint_symbol(char *buffer, unsigned long addr)
 134{
 135        *buffer = '\0';
 136        return 0;
 137}
 138
 139static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 140{
 141        *buffer = '\0';
 142        return 0;
 143}
 144
 145static inline int sprint_backtrace(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 int kallsyms_show_value(void)
 162{
 163        return false;
 164}
 165
 166#endif /*CONFIG_KALLSYMS*/
 167
 168static 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*/
 174