sysdeps/arc/dl-runtime.h

   1 /* Helpers for On-demand PLT fixup for shared objects.  ARC version.
   2    Copyright (C) 2020-2022 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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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 /* PLT jump into resolver passes PC of PLTn, while _dl_fixup expects the
  20    address of corresponding .rela.plt entry.
  21
  22     - @plt0: runtime pc of first plt entry (DT_PLTGOT)
  23     - @pltn: runtime pc of plt entry being resolved
  24     - @size: size of .plt.rela entry (unused).  */
  25 static inline uintptr_t
  26 reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size)
  27 {
  28   unsigned long int idx = pltn - plt0;
  29
  30   /* PLT trampoline is 16 bytes.  */
  31   idx /= 16;
  32
  33   /* Exclude PLT0 and PLT1.  */
  34   return idx - 2;
  35 }
  36
  37 static inline uintptr_t
  38 reloc_offset (uintptr_t plt0, uintptr_t pltn)
  39 {
  40   size_t sz = sizeof (ElfW(Rela));
  41   return reloc_index (plt0, pltn, sz) * sz;
  42 }