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
 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	guard(rcu)();
 59	mod = __module_address((unsigned long)ptr);
 60
 61	if (mod)
 62		ptr = dereference_module_function_descriptor(mod, ptr);
 63#endif
 64	return ptr;
 65}
 66
 67/* How and when do we show kallsyms values? */
 68extern bool kallsyms_show_value(const struct cred *cred);
 69
 70#ifdef CONFIG_KALLSYMS
 71unsigned long kallsyms_sym_address(int idx);
 72int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
 73			    void *data);
 74int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
 75				  const char *name, void *data);
 76
 77/* Lookup the address for a symbol. Returns 0 if not found. */
 78unsigned long kallsyms_lookup_name(const char *name);
 79
 80extern int kallsyms_lookup_size_offset(unsigned long addr,
 81				  unsigned long *symbolsize,
 82				  unsigned long *offset);
 83
 84/* Lookup an address.  modname is set to NULL if it's in the kernel. */
 85const char *kallsyms_lookup(unsigned long addr,
 86			    unsigned long *symbolsize,
 87			    unsigned long *offset,
 88			    char **modname, char *namebuf);
 89
 90/* Look up a kernel symbol and return it in a text buffer. */
 91extern int sprint_symbol(char *buffer, unsigned long address);
 92extern int sprint_symbol_build_id(char *buffer, unsigned long address);
 93extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
 94extern int sprint_backtrace(char *buffer, unsigned long address);
 95extern int sprint_backtrace_build_id(char *buffer, unsigned long address);
 96
 97int lookup_symbol_name(unsigned long addr, char *symname);
 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 kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
157					  void *data)
158{
159	return -EOPNOTSUPP;
160}
161
162static inline int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
163						const char *name, void *data)
164{
165	return -EOPNOTSUPP;
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*/