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 | |
David Daney | d219e2e | 2012-04-19 14:59:56 -0700 | [diff] [blame] | 38 | /* Cleared by build time tools if the table is already sorted. */ |
Andi Kleen | 00b7103 | 2014-02-08 08:52:04 +0100 | [diff] [blame] | 39 | u32 __initdata __visible main_extable_sort_needed = 1; |
David Daney | d219e2e | 2012-04-19 14:59:56 -0700 | [diff] [blame] | 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | /* Sort the kernel's built-in exception table */ |
| 42 | void __init sort_main_extable(void) |
| 43 | { |
Uwe Kleine-König | e656a63 | 2013-09-11 14:23:27 -0700 | [diff] [blame] | 44 | if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) { |
Borislav Petkov | bec1b9e | 2013-04-15 12:51:49 +0200 | [diff] [blame] | 45 | pr_notice("Sorting __ex_table...\n"); |
David Daney | d219e2e | 2012-04-19 14:59:56 -0700 | [diff] [blame] | 46 | sort_extable(__start___ex_table, __stop___ex_table); |
Borislav Petkov | bec1b9e | 2013-04-15 12:51:49 +0200 | [diff] [blame] | 47 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | } |
| 49 | |
| 50 | /* Given an address, look for it in the exception tables. */ |
| 51 | const struct exception_table_entry *search_exception_tables(unsigned long addr) |
| 52 | { |
| 53 | const struct exception_table_entry *e; |
| 54 | |
| 55 | e = search_extable(__start___ex_table, __stop___ex_table-1, addr); |
| 56 | if (!e) |
| 57 | e = search_module_extables(addr); |
| 58 | return e; |
| 59 | } |
| 60 | |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 61 | static inline int init_kernel_text(unsigned long addr) |
| 62 | { |
| 63 | if (addr >= (unsigned long)_sinittext && |
Helge Deller | 5ecbe3c | 2013-11-28 09:16:33 +0100 | [diff] [blame] | 64 | addr < (unsigned long)_einittext) |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 65 | return 1; |
| 66 | return 0; |
| 67 | } |
| 68 | |
Marcin Nowakowski | 717ce69 | 2017-07-06 15:35:31 -0700 | [diff] [blame] | 69 | int notrace core_kernel_text(unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | { |
| 71 | if (addr >= (unsigned long)_stext && |
Helge Deller | 5ecbe3c | 2013-11-28 09:16:33 +0100 | [diff] [blame] | 72 | addr < (unsigned long)_etext) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | return 1; |
| 74 | |
Rusty Russell | a2da405 | 2008-01-29 17:13:17 -0500 | [diff] [blame] | 75 | if (system_state == SYSTEM_BOOTING && |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 76 | init_kernel_text(addr)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | return 1; |
| 78 | return 0; |
| 79 | } |
| 80 | |
Steven Rostedt | a2d063a | 2011-05-19 21:34:58 -0400 | [diff] [blame] | 81 | /** |
| 82 | * core_kernel_data - tell if addr points to kernel data |
| 83 | * @addr: address to test |
| 84 | * |
| 85 | * Returns true if @addr passed in is from the core kernel data |
| 86 | * section. |
| 87 | * |
| 88 | * Note: On some archs it may return true for core RODATA, and false |
| 89 | * for others. But will always be true for core RW data. |
| 90 | */ |
Steven Rostedt | cdbe61b | 2011-05-05 21:14:55 -0400 | [diff] [blame] | 91 | int core_kernel_data(unsigned long addr) |
| 92 | { |
Steven Rostedt | a2d063a | 2011-05-19 21:34:58 -0400 | [diff] [blame] | 93 | if (addr >= (unsigned long)_sdata && |
Steven Rostedt | cdbe61b | 2011-05-05 21:14:55 -0400 | [diff] [blame] | 94 | addr < (unsigned long)_edata) |
| 95 | return 1; |
| 96 | return 0; |
| 97 | } |
| 98 | |
Frederic Weisbecker | 3861a17 | 2009-02-08 00:04:02 +0100 | [diff] [blame] | 99 | int __kernel_text_address(unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | { |
| 101 | if (core_kernel_text(addr)) |
| 102 | return 1; |
Linus Torvalds | cab4e4c | 2009-04-05 10:30:21 -0700 | [diff] [blame] | 103 | if (is_module_text_address(addr)) |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 104 | return 1; |
Steven Rostedt (Red Hat) | aec0be2 | 2014-11-18 21:14:11 -0500 | [diff] [blame] | 105 | if (is_ftrace_trampoline(addr)) |
| 106 | return 1; |
Ingo Molnar | 4a44bac | 2009-03-19 13:21:44 +0100 | [diff] [blame] | 107 | /* |
| 108 | * There might be init symbols in saved stacktraces. |
| 109 | * Give those symbols a chance to be printed in |
| 110 | * backtraces (such as lockdep traces). |
| 111 | * |
| 112 | * Since we are after the module-symbols check, there's |
| 113 | * no danger of address overlap: |
| 114 | */ |
| 115 | if (init_kernel_text(addr)) |
| 116 | return 1; |
| 117 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | int kernel_text_address(unsigned long addr) |
| 121 | { |
| 122 | if (core_kernel_text(addr)) |
| 123 | return 1; |
Steven Rostedt (Red Hat) | aec0be2 | 2014-11-18 21:14:11 -0500 | [diff] [blame] | 124 | if (is_module_text_address(addr)) |
| 125 | return 1; |
| 126 | return is_ftrace_trampoline(addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | } |
Arjan van de Ven | ab7476c | 2008-08-15 15:29:38 -0700 | [diff] [blame] | 128 | |
| 129 | /* |
| 130 | * On some architectures (PPC64, IA64) function pointers |
| 131 | * are actually only tokens to some data that then holds the |
| 132 | * real function address. As a result, to find if a function |
| 133 | * pointer is part of the kernel text, we need to do some |
| 134 | * special dereferencing first. |
| 135 | */ |
| 136 | int func_ptr_is_kernel_text(void *ptr) |
| 137 | { |
| 138 | unsigned long addr; |
| 139 | addr = (unsigned long) dereference_function_descriptor(ptr); |
| 140 | if (core_kernel_text(addr)) |
| 141 | return 1; |
Rusty Russell | a6e6abd | 2009-03-31 13:05:31 -0600 | [diff] [blame] | 142 | return is_module_text_address(addr); |
Arjan van de Ven | ab7476c | 2008-08-15 15:29:38 -0700 | [diff] [blame] | 143 | } |