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
reloc_index(uintptr_t plt0,uintptr_t pltn,size_t size)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
reloc_offset(uintptr_t plt0,uintptr_t pltn)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 }
43