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 * NOT exported to modules - patching kernel text is a really delicate matter.
33 DEFINE_MUTEX(text_mutex
);
35 extern struct exception_table_entry __start___ex_table
[];
36 extern struct exception_table_entry __stop___ex_table
[];
38 /* Sort the kernel's built-in exception table */
39 void __init
sort_main_extable(void)
41 sort_extable(__start___ex_table
, __stop___ex_table
);
44 /* Given an address, look for it in the exception tables. */
45 const struct exception_table_entry
*search_exception_tables(unsigned long addr
)
47 const struct exception_table_entry
*e
;
49 e
= search_extable(__start___ex_table
, __stop___ex_table
-1, addr
);
51 e
= search_module_extables(addr
);
55 int core_kernel_text(unsigned long addr
)
57 if (addr
>= (unsigned long)_stext
&&
58 addr
<= (unsigned long)_etext
)
61 if (system_state
== SYSTEM_BOOTING
&&
62 addr
>= (unsigned long)_sinittext
&&
63 addr
<= (unsigned long)_einittext
)
68 int __kernel_text_address(unsigned long addr
)
70 if (core_kernel_text(addr
))
72 return __module_text_address(addr
) != NULL
;
75 int kernel_text_address(unsigned long addr
)
77 if (core_kernel_text(addr
))
79 return module_text_address(addr
) != NULL
;
83 * On some architectures (PPC64, IA64) function pointers
84 * are actually only tokens to some data that then holds the
85 * real function address. As a result, to find if a function
86 * pointer is part of the kernel text, we need to do some
87 * special dereferencing first.
89 int func_ptr_is_kernel_text(void *ptr
)
92 addr
= (unsigned long) dereference_function_descriptor(ptr
);
93 if (core_kernel_text(addr
))
95 return module_text_address(addr
) != NULL
;