1  /* Pointer obfuscation implenentation.  Generic (no-op) version.
       2     Copyright (C) 2005-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef POINTER_GUARD_H
      20  #define POINTER_GUARD_H
      21  
      22  #if IS_IN (rtld)
      23  /* We cannot use the thread descriptor because in ld.so we use setjmp
      24     earlier than the descriptor is initialized.  Using a global variable
      25     is too complicated here since we have no PC-relative addressing mode.  */
      26  # include <sysdeps/generic/pointer_guard.h>
      27  #else
      28  # ifdef __ASSEMBLER__
      29  #  define PTR_MANGLE(reg, tmp) \
      30       stc gbr,tmp; mov.l @(POINTER_GUARD,tmp),tmp; xor tmp,reg
      31  #  define PTR_MANGLE2(reg, tmp) xor tmp,reg
      32  #  define PTR_DEMANGLE(reg, tmp)        PTR_MANGLE (reg, tmp)
      33  #  define PTR_DEMANGLE2(reg, tmp)       PTR_MANGLE2 (reg, tmp)
      34  # else
      35  #  include <stdint.h>
      36  #  include <tls.h>
      37  #  define PTR_MANGLE(var) \
      38       (var) = (void *) ((uintptr_t) (var) ^ THREAD_GET_POINTER_GUARD ())
      39  #  define PTR_DEMANGLE(var)     PTR_MANGLE (var)
      40  # endif
      41  #endif
      42  
      43  #endif /* POINTER_GUARD_H */