1 /* Rewritten by Rusty Russell, on the backs of many others...
2 Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
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.
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.
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
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>
24 #include <asm/sections.h>
25 #include <asm/uaccess.h>
28 * mutex protecting text section modification (dynamic code patching).
29 * some users need to sleep (allocating memory...) while they hold this lock.
31 * Note: Also protects SMP-alternatives modification on x86.
33 * NOT exported to modules - patching kernel text is a really delicate matter.
35 DEFINE_MUTEX(text_mutex);
37 extern struct exception_table_entry __start___ex_table[];
38 extern struct exception_table_entry __stop___ex_table[];
40 /* Sort the kernel's built-in exception table */
41 void __init sort_main_extable(void)
43 sort_extable(__start___ex_table, __stop___ex_table);
46 /* Given an address, look for it in the exception tables. */
47 const struct exception_table_entry *search_exception_tables(unsigned long addr)
49 const struct exception_table_entry *e;
51 e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
53 e = search_module_extables(addr);
57 static inline int init_kernel_text(unsigned long addr)
59 if (addr >= (unsigned long)_sinittext &&
60 addr <= (unsigned long)_einittext)
65 int core_kernel_text(unsigned long addr)
67 if (addr >= (unsigned long)_stext &&
68 addr <= (unsigned long)_etext)
71 if (system_state == SYSTEM_BOOTING &&
72 init_kernel_text(addr))
78 * core_kernel_data - tell if addr points to kernel data
79 * @addr: address to test
81 * Returns true if @addr passed in is from the core kernel data
84 * Note: On some archs it may return true for core RODATA, and false
85 * for others. But will always be true for core RW data.
87 int core_kernel_data(unsigned long addr)
89 if (addr >= (unsigned long)_sdata &&
90 addr < (unsigned long)_edata)
95 int __kernel_text_address(unsigned long addr)
97 if (core_kernel_text(addr))
99 if (is_module_text_address(addr))
102 * There might be init symbols in saved stacktraces.
103 * Give those symbols a chance to be printed in
104 * backtraces (such as lockdep traces).
106 * Since we are after the module-symbols check, there's
107 * no danger of address overlap:
109 if (init_kernel_text(addr))
114 int kernel_text_address(unsigned long addr)
116 if (core_kernel_text(addr))
118 return is_module_text_address(addr);
122 * On some architectures (PPC64, IA64) function pointers
123 * are actually only tokens to some data that then holds the
124 * real function address. As a result, to find if a function
125 * pointer is part of the kernel text, we need to do some
126 * special dereferencing first.
128 int func_ptr_is_kernel_text(void *ptr)
131 addr = (unsigned long) dereference_function_descriptor(ptr);
132 if (core_kernel_text(addr))
134 return is_module_text_address(addr);