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
  21 struct cred;
  22 struct module;
  23
  24 static 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
  32 static 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
  40 static 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
  47 static 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
  55 static 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 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
  75                                       unsigned long),
  76                             void *data);
  77
  78 #ifdef CONFIG_KALLSYMS
  79 /* Lookup the address for a symbol. Returns 0 if not found. */
  80 unsigned long kallsyms_lookup_name(const char *name);
  81
  82 extern 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. */
  87 const 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. */
  93 extern int sprint_symbol(char *buffer, unsigned long address);
  94 extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
  95 extern int sprint_backtrace(char *buffer, unsigned long address);
  96
  97 int lookup_symbol_name(unsigned long addr, char *symname);
  98 int 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? */
 101 extern bool kallsyms_show_value(const struct cred *cred);
 102
 103 #else /* !CONFIG_KALLSYMS */
 104
 105 static inline unsigned long kallsyms_lookup_name(const char *name)
 106 {
 107         return 0;
 108 }
 109
 110 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 111                                               unsigned long *symbolsize,
 112                                               unsigned long *offset)
 113 {
 114         return 0;
 115 }
 116
 117 static inline const char *kallsyms_lookup(unsigned long addr,
 118                                           unsigned long *symbolsize,
 119                                           unsigned long *offset,
 120                                           char **modname, char *namebuf)
 121 {
 122         return NULL;
 123 }
 124
 125 static inline int sprint_symbol(char *buffer, unsigned long addr)
 126 {
 127         *buffer = '\0';
 128         return 0;
 129 }
 130
 131 static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
 132 {
 133         *buffer = '\0';
 134         return 0;
 135 }
 136
 137 static inline int sprint_backtrace(char *buffer, unsigned long addr)
 138 {
 139         *buffer = '\0';
 140         return 0;
 141 }
 142
 143 static inline int lookup_symbol_name(unsigned long addr, char *symname)
 144 {
 145         return -ERANGE;
 146 }
 147
 148 static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
 149 {
 150         return -ERANGE;
 151 }
 152
 153 static inline bool kallsyms_show_value(const struct cred *cred)
 154 {
 155         return false;
 156 }
 157
 158 #endif /*CONFIG_KALLSYMS*/
 159
 160 static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 161 {
 162         printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 163 }
 164
 165 #endif /*_LINUX_KALLSYMS_H*/