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