Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | */ |
Frederic Weisbecker | 8b96f01 | 2008-12-06 03:40:00 +0100 | [diff] [blame] | 18 | #include <linux/ftrace.h> |
Dmitri Vorobiev | f80d2d7 | 2009-03-22 19:11:10 +0200 | [diff] [blame] | 19 | #include <linux/memory.h> |
Ingo Molnar | 505f2b9 | 2009-03-20 11:05:04 +0100 | [diff] [blame] | 20 | #include <linux/module.h> |
| 21 | #include <linux/mutex.h> |
| 22 | #include <linux/init.h> |
| 23 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <asm/sections.h> |
Ingo Molnar | 505f2b9 | 2009-03-20 11:05:04 +0100 | [diff] [blame] | 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 | */ |
| 33 | DEFINE_MUTEX(text_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
| 35 | extern struct exception_table_entry __start___ex_table[]; |
| 36 | extern struct exception_table_entry __stop___ex_table[]; |
| 37 | |
| 38 | /* Sort the kernel's built-in exception table */ |
| 39 | void __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. */ |
| 45 | const 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 Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 55 | static 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 Weisbecker | 3861a17 | 2009-02-08 00:04:02 +0100 | [diff] [blame] | 63 | int core_kernel_text(unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | { |
| 65 | if (addr >= (unsigned long)_stext && |
| 66 | addr <= (unsigned long)_etext) |
| 67 | return 1; |
| 68 | |
Rusty Russell | a2da405 | 2008-01-29 17:13:17 -0500 | [diff] [blame] | 69 | if (system_state == SYSTEM_BOOTING && |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 70 | init_kernel_text(addr)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | return 1; |
| 72 | return 0; |
| 73 | } |
| 74 | |
Frederic Weisbecker | 3861a17 | 2009-02-08 00:04:02 +0100 | [diff] [blame] | 75 | int __kernel_text_address(unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | { |
| 77 | if (core_kernel_text(addr)) |
| 78 | return 1; |
Linus Torvalds | cab4e4c | 2009-04-05 10:30:21 -0700 | [diff] [blame] | 79 | if (is_module_text_address(addr)) |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 80 | 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | } |
| 93 | |
| 94 | int kernel_text_address(unsigned long addr) |
| 95 | { |
| 96 | if (core_kernel_text(addr)) |
| 97 | return 1; |
Rusty Russell | a6e6abd | 2009-03-31 13:05:31 -0600 | [diff] [blame] | 98 | return is_module_text_address(addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | } |
Arjan van de Ven | ab7476c | 2008-08-15 15:29:38 -0700 | [diff] [blame] | 100 | |
| 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 | */ |
| 108 | int 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 Russell | a6e6abd | 2009-03-31 13:05:31 -0600 | [diff] [blame] | 114 | return is_module_text_address(addr); |
Arjan van de Ven | ab7476c | 2008-08-15 15:29:38 -0700 | [diff] [blame] | 115 | } |