kernel/extable.c

   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 */
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/ftrace.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/sections.h>
  23
  24 extern struct exception_table_entry __start___ex_table[];
  25 extern struct exception_table_entry __stop___ex_table[];
  26
  27 /* Sort the kernel's built-in exception table */
  28 void __init sort_main_extable(void)
  29 {
  30         sort_extable(__start___ex_table, __stop___ex_table);
  31 }
  32
  33 /* Given an address, look for it in the exception tables. */
  34 const struct exception_table_entry *search_exception_tables(unsigned long addr)
  35 {
  36         const struct exception_table_entry *e;
  37
  38         e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
  39         if (!e)
  40                 e = search_module_extables(addr);
  41         return e;
  42 }
  43
  44 static inline int init_kernel_text(unsigned long addr)
  45 {
  46         if (addr >= (unsigned long)_sinittext &&
  47             addr <= (unsigned long)_einittext)
  48                 return 1;
  49         return 0;
  50 }
  51
  52 __notrace_funcgraph int core_kernel_text(unsigned long addr)
  53 {
  54         if (addr >= (unsigned long)_stext &&
  55             addr <= (unsigned long)_etext)
  56                 return 1;
  57
  58         if (system_state == SYSTEM_BOOTING &&
  59             init_kernel_text(addr))
  60                 return 1;
  61         return 0;
  62 }
  63
  64 __notrace_funcgraph int __kernel_text_address(unsigned long addr)
  65 {
  66         if (core_kernel_text(addr))
  67                 return 1;
  68         if (__module_text_address(addr))
  69                 return 1;
  70         /*
  71          * There might be init symbols in saved stacktraces.
  72          * Give those symbols a chance to be printed in
  73          * backtraces (such as lockdep traces).
  74          *
  75          * Since we are after the module-symbols check, there's
  76          * no danger of address overlap:
  77          */
  78         if (init_kernel_text(addr))
  79                 return 1;
  80         return 0;
  81 }
  82
  83 int kernel_text_address(unsigned long addr)
  84 {
  85         if (core_kernel_text(addr))
  86                 return 1;
  87         return module_text_address(addr) != NULL;
  88 }
  89
  90 /*
  91  * On some architectures (PPC64, IA64) function pointers
  92  * are actually only tokens to some data that then holds the
  93  * real function address. As a result, to find if a function
  94  * pointer is part of the kernel text, we need to do some
  95  * special dereferencing first.
  96  */
  97 int func_ptr_is_kernel_text(void *ptr)
  98 {
  99         unsigned long addr;
 100         addr = (unsigned long) dereference_function_descriptor(ptr);
 101         if (core_kernel_text(addr))
 102                 return 1;
 103         return module_text_address(addr) != NULL;
 104 }