1/* Inline functions for dynamic linking.
2 Copyright (C) 1995-2022 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
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#include <dl-machine.h>
20#include <elf.h>
21
22#ifdef RESOLVE_MAP
23/* We pass reloc_addr as a pointer to void, as opposed to a pointer to
24 ElfW(Addr), because not all architectures can assume that the
25 relocated address is properly aligned, whereas the compiler is
26 entitled to assume that a pointer to a type is properly aligned for
27 the type. Even if we cast the pointer back to some other type with
28 less strict alignment requirements, the compiler might still
29 remember that the pointer was originally more aligned, thereby
30 optimizing away alignment tests or using word instructions for
31 copying memory, breaking the very code written to handle the
32 unaligned cases. */
33# if ! ELF_MACHINE_NO_REL
34static inline void __attribute__((always_inline))
35elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
36 const ElfW(Rel) *reloc, const ElfW(Sym) *sym,
37 const struct r_found_version *version,
38 void *const reloc_addr, int skip_ifunc);
39static inline void __attribute__((always_inline))
40elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
41 void *const reloc_addr);
42# endif
43# if ! ELF_MACHINE_NO_RELA
44static inline void __attribute__((always_inline))
45elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
46 const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
47 const struct r_found_version *version, void *const reloc_addr,
48 int skip_ifunc);
49static inline void __attribute__((always_inline))
50elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
51 void *const reloc_addr);
52# endif
53# if ELF_MACHINE_NO_RELA || defined ELF_MACHINE_PLT_REL
54static inline void __attribute__((always_inline))
55elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
56 ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
57 int skip_ifunc);
58# else
59static inline void __attribute__((always_inline))
60elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
61 ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
62 int skip_ifunc);
63# endif
64#endif
65
66#ifdef RESOLVE_MAP
67
68/* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
69 These functions are almost identical, so we use cpp magic to avoid
70 duplicating their code. It cannot be done in a more general function
71 because we must be able to completely inline. */
72
73/* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
74 range. Note that according to the ELF spec, this is completely legal!
75
76 We are guarenteed that we have one of three situations. Either DT_JMPREL
77 comes immediately after DT_REL*, or there is overlap and DT_JMPREL
78 consumes precisely the very end of the DT_REL*, or DT_JMPREL and DT_REL*
79 are completely separate and there is a gap between them. */
80
81# define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, scope, do_lazy, skip_ifunc, test_rel) \
82 do { \
83 struct { ElfW(Addr) start, size; \
84 __typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative; int lazy; } \
85 ranges[2] = { { 0, 0, 0, 0 }, { 0, 0, 0, 0 } }; \
86 \
87 if ((map)->l_info[DT_##RELOC]) \
88 { \
89 ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]); \
90 ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val; \
91 if (map->l_info[VERSYMIDX (DT_##RELOC##COUNT)] != NULL) \
92 ranges[0].nrelative \
93 = map->l_info[VERSYMIDX (DT_##RELOC##COUNT)]->d_un.d_val; \
94 } \
95 if ((map)->l_info[DT_PLTREL] \
96 && (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
97 { \
98 ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]); \
99 ElfW(Addr) size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val; \
100 \
101 if (ranges[0].start + ranges[0].size == (start + size)) \
102 ranges[0].size -= size; \
103 if (!(do_lazy) \
104 && (ranges[0].start + ranges[0].size) == start) \
105 { \
106 /* Combine processing the sections. */ \
107 ranges[0].size += size; \
108 } \
109 else \
110 { \
111 ranges[1].start = start; \
112 ranges[1].size = size; \
113 ranges[1].lazy = (do_lazy); \
114 } \
115 } \
116 \
117 for (int ranges_index = 0; ranges_index < 2; ++ranges_index) \
118 elf_dynamic_do_##reloc ((map), scope, \
119 ranges[ranges_index].start, \
120 ranges[ranges_index].size, \
121 ranges[ranges_index].nrelative, \
122 ranges[ranges_index].lazy, \
123 skip_ifunc); \
124 } while (0)
125
126# if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
127# define _ELF_CHECK_REL 0
128# else
129# define _ELF_CHECK_REL 1
130# endif
131
132# if ! ELF_MACHINE_NO_REL
133# include "do-rel.h"
134# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) \
135 _ELF_DYNAMIC_DO_RELOC (REL, Rel, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
136# else
137# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) /* Nothing to do. */
138# endif
139
140# if ! ELF_MACHINE_NO_RELA
141# define DO_RELA
142# include "do-rel.h"
143# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) \
144 _ELF_DYNAMIC_DO_RELOC (RELA, Rela, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
145# else
146# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) /* Nothing to do. */
147# endif
148
149/* This can't just be an inline function because GCC is too dumb
150 to inline functions containing inlines themselves. */
151# define ELF_DYNAMIC_RELOCATE(map, scope, lazy, consider_profile, skip_ifunc) \
152 do { \
153 int edr_lazy = elf_machine_runtime_setup ((map), (scope), (lazy), \
154 (consider_profile)); \
155 ELF_DYNAMIC_DO_REL ((map), (scope), edr_lazy, skip_ifunc); \
156 ELF_DYNAMIC_DO_RELA ((map), (scope), edr_lazy, skip_ifunc); \
157 } while (0)
158
159#endif
160