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