| 1 | |
| 2 | Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
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| 3 |
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| 4 | This program is free software; you can redistribute it and/or modify
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| 5 | it under the terms of the GNU General Public License as published by
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| 6 | the Free Software Foundation; either version 2 of the License, or
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| 7 | (at your option) any later version.
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| 8 |
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| 9 | This program is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU General Public License
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| 15 | along with this program; if not, write to the Free Software
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| 16 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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| 17 |
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| 18 | #include <linux/ftrace.h>
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| 19 | #include <linux/memory.h>
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| 20 | #include <linux/module.h>
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| 21 | #include <linux/mutex.h>
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| 22 | #include <linux/init.h>
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| 23 |
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| 24 | #include <asm/sections.h>
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| 25 | #include <asm/uaccess.h>
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| 26 |
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| 27 | |
| 28 | * mutex protecting text section modification (dynamic code patching).
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| 29 | * some users need to sleep (allocating memory...) while they hold this lock.
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| 30 | *
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| 31 | * NOT exported to modules - patching kernel text is a really delicate matter.
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| 32 |
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| 33 | DEFINE_MUTEX(text_mutex);
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| 34 |
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| 35 | extern struct exception_table_entry __start___ex_table[];
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| 36 | extern struct exception_table_entry __stop___ex_table[];
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| 37 |
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| 38 |
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| 39 | u32 __initdata __visible main_extable_sort_needed = 1;
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| 40 |
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| 41 |
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| 42 | void __init sort_main_extable(void)
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| 43 | {
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| 44 | if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) {
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| 45 | pr_notice("Sorting __ex_table...\n");
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| 46 | sort_extable(__start___ex_table, __stop___ex_table);
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| 47 | }
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| 48 | }
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| 49 |
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| 50 |
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| 51 | const struct exception_table_entry *search_exception_tables(unsigned long addr)
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| 52 | {
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| 53 | const struct exception_table_entry *e;
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| 54 |
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| 55 | e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
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| 56 | if (!e)
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| 57 | e = search_module_extables(addr);
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| 58 | return e;
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| 59 | }
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| 60 |
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| 61 | static inline int init_kernel_text(unsigned long addr)
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| 62 | {
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| 63 | if (addr >= (unsigned long)_sinittext &&
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| 64 | addr < (unsigned long)_einittext)
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| 65 | return 1;
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| 66 | return 0;
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| 67 | }
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| 68 |
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| 69 | int core_kernel_text(unsigned long addr)
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| 70 | {
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| 71 | if (addr >= (unsigned long)_stext &&
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| 72 | addr < (unsigned long)_etext)
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| 73 | return 1;
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| 74 |
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| 75 | if (system_state == SYSTEM_BOOTING &&
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| 76 | init_kernel_text(addr))
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| 77 | return 1;
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| 78 | return 0;
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| 79 | }
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| 80 |
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| 81 | |
| 82 | * core_kernel_data - tell if addr points to kernel data
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| 83 | * @addr: address to test
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| 84 | *
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| 85 | * Returns true if @addr passed in is from the core kernel data
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| 86 | * section.
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| 87 | *
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| 88 | * Note: On some archs it may return true for core RODATA, and false
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| 89 | * for others. But will always be true for core RW data.
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| 90 |
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| 91 | int core_kernel_data(unsigned long addr)
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| 92 | {
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| 93 | if (addr >= (unsigned long)_sdata &&
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| 94 | addr < (unsigned long)_edata)
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| 95 | return 1;
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| 96 | return 0;
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| 97 | }
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| 98 |
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| 99 | int __kernel_text_address(unsigned long addr)
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| 100 | {
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| 101 | if (core_kernel_text(addr))
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| 102 | return 1;
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| 103 | if (is_module_text_address(addr))
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| 104 | return 1;
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| 105 | if (is_ftrace_trampoline(addr))
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| 106 | return 1;
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| 107 | |
| 108 | * There might be init symbols in saved stacktraces.
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| 109 | * Give those symbols a chance to be printed in
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| 110 | * backtraces (such as lockdep traces).
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| 111 | *
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| 112 | * Since we are after the module-symbols check, there's
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| 113 | * no danger of address overlap:
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| 114 |
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| 115 | if (init_kernel_text(addr))
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| 116 | return 1;
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| 117 | return 0;
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| 118 | }
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| 119 |
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| 120 | int kernel_text_address(unsigned long addr)
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| 121 | {
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| 122 | if (core_kernel_text(addr))
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| 123 | return 1;
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| 124 | if (is_module_text_address(addr))
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| 125 | return 1;
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| 126 | return is_ftrace_trampoline(addr);
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| 127 | }
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| 128 |
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| 129 | |
| 130 | * On some architectures (PPC64, IA64) function pointers
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| 131 | * are actually only tokens to some data that then holds the
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| 132 | * real function address. As a result, to find if a function
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| 133 | * pointer is part of the kernel text, we need to do some
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| 134 | * special dereferencing first.
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| 135 |
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| 136 | int func_ptr_is_kernel_text(void *ptr)
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| 137 | {
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| 138 | unsigned long addr;
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| 139 | addr = (unsigned long) dereference_function_descriptor(ptr);
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| 140 | if (core_kernel_text(addr))
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| 141 | return 1;
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| 142 | return is_module_text_address(addr);
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| 143 | }
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