projects/linux·blob v3.3-rc4 · refs

133 lines · 3.7 KiB

1/* Rewritten by Rusty Russell, on the backs of many others...
2 Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17*/
18#include <linux/ftrace.h>
19#include <linux/memory.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/init.h>
23
24#include <asm/sections.h>
25#include <asm/uaccess.h>
26
27/*
28 * mutex protecting text section modification (dynamic code patching).
29 * some users need to sleep (allocating memory...) while they hold this lock.
30 *
31 * NOT exported to modules - patching kernel text is a really delicate matter.
32 */
33DEFINE_MUTEX(text_mutex);
34
35extern struct exception_table_entry __start___ex_table[];
36extern struct exception_table_entry __stop___ex_table[];
37
38/* Sort the kernel's built-in exception table */
39void __init sort_main_extable(void)
40{
41 sort_extable(__start___ex_table, __stop___ex_table);
42}
43
44/* Given an address, look for it in the exception tables. */
45const struct exception_table_entry *search_exception_tables(unsigned long addr)
46{
47 const struct exception_table_entry *e;
48
49 e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
50 if (!e)
51 e = search_module_extables(addr);
52 return e;
53}
54
55static inline int init_kernel_text(unsigned long addr)
56{
57 if (addr >= (unsigned long)_sinittext &&
58 addr <= (unsigned long)_einittext)
59 return 1;
60 return 0;
61}
62
63int core_kernel_text(unsigned long addr)
64{
65 if (addr >= (unsigned long)_stext &&
66 addr <= (unsigned long)_etext)
67 return 1;
68
69 if (system_state == SYSTEM_BOOTING &&
70 init_kernel_text(addr))
71 return 1;
72 return 0;
73}
74
75/**
76 * core_kernel_data - tell if addr points to kernel data
77 * @addr: address to test
78 *
79 * Returns true if @addr passed in is from the core kernel data
80 * section.
81 *
82 * Note: On some archs it may return true for core RODATA, and false
83 * for others. But will always be true for core RW data.
84 */
85int core_kernel_data(unsigned long addr)
86{
87 if (addr >= (unsigned long)_sdata &&
88 addr < (unsigned long)_edata)
89 return 1;
90 return 0;
91}
92
93int __kernel_text_address(unsigned long addr)
94{
95 if (core_kernel_text(addr))
96 return 1;
97 if (is_module_text_address(addr))
98 return 1;
99 /*
100 * There might be init symbols in saved stacktraces.
101 * Give those symbols a chance to be printed in
102 * backtraces (such as lockdep traces).
103 *
104 * Since we are after the module-symbols check, there's
105 * no danger of address overlap:
106 */
107 if (init_kernel_text(addr))
108 return 1;
109 return 0;
110}
111
112int kernel_text_address(unsigned long addr)
113{
114 if (core_kernel_text(addr))
115 return 1;
116 return is_module_text_address(addr);
117}
118
119/*
120 * On some architectures (PPC64, IA64) function pointers
121 * are actually only tokens to some data that then holds the
122 * real function address. As a result, to find if a function
123 * pointer is part of the kernel text, we need to do some
124 * special dereferencing first.
125 */
126int func_ptr_is_kernel_text(void *ptr)
127{
128 unsigned long addr;
129 addr = (unsigned long) dereference_function_descriptor(ptr);
130 if (core_kernel_text(addr))
131 return 1;
132 return is_module_text_address(addr);
133}