blob: 7f8f263f85249a15ca8492fa5056c868262aa0f1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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*/
Frederic Weisbecker8b96f012008-12-06 03:40:00 +010018#include <linux/ftrace.h>
Dmitri Vorobievf80d2d72009-03-22 19:11:10 +020019#include <linux/memory.h>
Ingo Molnar505f2b92009-03-20 11:05:04 +010020#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/init.h>
23
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <asm/sections.h>
Ingo Molnar505f2b92009-03-20 11:05:04 +010025#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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
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
Ingo Molnar4a44bac2009-03-19 13:21:44 +010055static 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
Frederic Weisbecker3861a172009-02-08 00:04:02 +010063int core_kernel_text(unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064{
65 if (addr >= (unsigned long)_stext &&
66 addr <= (unsigned long)_etext)
67 return 1;
68
Rusty Russella2da4052008-01-29 17:13:17 -050069 if (system_state == SYSTEM_BOOTING &&
Ingo Molnar4a44bac2009-03-19 13:21:44 +010070 init_kernel_text(addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 return 1;
72 return 0;
73}
74
Frederic Weisbecker3861a172009-02-08 00:04:02 +010075int __kernel_text_address(unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070076{
77 if (core_kernel_text(addr))
78 return 1;
Linus Torvaldscab4e4c2009-04-05 10:30:21 -070079 if (is_module_text_address(addr))
Ingo Molnar4a44bac2009-03-19 13:21:44 +010080 return 1;
81 /*
82 * There might be init symbols in saved stacktraces.
83 * Give those symbols a chance to be printed in
84 * backtraces (such as lockdep traces).
85 *
86 * Since we are after the module-symbols check, there's
87 * no danger of address overlap:
88 */
89 if (init_kernel_text(addr))
90 return 1;
91 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092}
93
94int kernel_text_address(unsigned long addr)
95{
96 if (core_kernel_text(addr))
97 return 1;
Rusty Russella6e6abd2009-03-31 13:05:31 -060098 return is_module_text_address(addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099}
Arjan van de Venab7476c2008-08-15 15:29:38 -0700100
101/*
102 * On some architectures (PPC64, IA64) function pointers
103 * are actually only tokens to some data that then holds the
104 * real function address. As a result, to find if a function
105 * pointer is part of the kernel text, we need to do some
106 * special dereferencing first.
107 */
108int func_ptr_is_kernel_text(void *ptr)
109{
110 unsigned long addr;
111 addr = (unsigned long) dereference_function_descriptor(ptr);
112 if (core_kernel_text(addr))
113 return 1;
Rusty Russella6e6abd2009-03-31 13:05:31 -0600114 return is_module_text_address(addr);
Arjan van de Venab7476c2008-08-15 15:29:38 -0700115}