1 /* Machine-dependent ELF dynamic relocation inline functions. m68k version.
2 Copyright (C) 1996-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
22 #define ELF_MACHINE_NAME "m68k"
24 #include <sys/param.h>
27 #include <dl-static-tls.h>
28 #include <dl-machine-rel.h>
30 /* Return nonzero iff ELF header is compatible with the running host. */
32 elf_machine_matches_host (const Elf32_Ehdr
*ehdr
)
34 return ehdr
->e_machine
== EM_68K
;
38 /* Return the link-time address of _DYNAMIC.
39 This must be inlined in a function which uses global data. */
40 static inline Elf32_Addr
41 elf_machine_dynamic (void)
45 asm ("move.l _DYNAMIC@GOT.w(%%a5), %0"
51 /* Return the run-time load address of the shared object. */
52 static inline Elf32_Addr
53 elf_machine_load_address (void)
57 asm (PCREL_OP ("lea", "_dl_start", "%0", "%0", "%%pc") "\n\t"
58 "sub.l _dl_start@GOT.w(%%a5), %0"
61 asm (PCREL_OP ("lea", "_dl_relocate_static_pie", "%0", "%0", "%%pc") "\n\t"
62 "sub.l _dl_relocate_static_pie@GOT.w(%%a5), %0"
69 /* Set up the loaded object described by L so its unrelocated PLT
70 entries will jump to the on-demand fixup code in dl-runtime.c. */
72 static inline int __attribute__ ((always_inline
))
73 elf_machine_runtime_setup (struct link_map
*l
, struct r_scope_elem
*scope
[],
74 int lazy
, int profile
)
77 extern void _dl_runtime_resolve (Elf32_Word
);
78 extern void _dl_runtime_profile (Elf32_Word
);
80 if (l
->l_info
[DT_JMPREL
] && lazy
)
82 /* The GOT entries for functions in the PLT have not yet been
83 filled in. Their initial contents will arrange when called
84 to push an offset into the .rela.plt section, push
85 _GLOBAL_OFFSET_TABLE_[1], and then jump to
86 _GLOBAL_OFFSET_TABLE_[2]. */
87 got
= (Elf32_Addr
*) D_PTR (l
, l_info
[DT_PLTGOT
]);
88 got
[1] = (Elf32_Addr
) l
; /* Identify this shared object. */
90 /* The got[2] entry contains the address of a function which gets
91 called to get the address of a so far unresolved function and
92 jump to it. The profiling extension of the dynamic linker allows
93 to intercept the calls to collect information. In this case we
94 don't store the address in the GOT so that all future calls also
95 end in this function. */
98 got
[2] = (Elf32_Addr
) &_dl_runtime_profile
;
100 if (GLRO(dl_profile
) != NULL
101 && _dl_name_match_p (GLRO(dl_profile
), l
))
103 /* This is the object we are looking for. Say that we really
104 want profiling and the timers are started. */
105 GL(dl_profile_map
) = l
;
109 /* This function will get called to fix up the GOT entry indicated by
110 the offset on the stack, and then jump to the resolved address. */
111 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
117 #define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0, long int save_a1
118 #define ELF_MACHINE_RUNTIME_FIXUP_PARAMS save_a0, save_a1
121 /* Mask identifying addresses reserved for the user program,
122 where the dynamic linker should not map anything. */
123 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
125 /* Initial entry point code for the dynamic linker.
126 The C function `_dl_start' is the real entry point;
127 its return value is the user program's entry point. */
129 #define RTLD_START asm ("\
132 .type _start,@function\n\
135 move.l %sp, -(%sp)\n\
140 .globl _dl_start_user\n\
141 .type _dl_start_user,@function\n\
143 | Save the user entry point address in %a4.\n\
145 | See if we were run as a command with the executable file\n\
146 | name as an extra leading argument.\n\
147 " PCREL_OP ("move.l", "_dl_skip_args", "%d0", "%d0", "%pc") "\n\
148 | Pop the original argument count\n\
149 move.l (%sp)+, %d1\n\
150 | Subtract _dl_skip_args from it.\n\
152 | Adjust the stack pointer to skip _dl_skip_args words.\n\
153 lea (%sp, %d0*4), %sp\n\
154 | Push back the modified argument count.\n\
155 move.l %d1, -(%sp)\n\
156 # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
159 move.l %d1, -(%sp)\n\
160 " PCREL_OP ("move.l", "_rtld_local", "-(%sp)", "%d0", "%pc") "\n\
164 | Pass our finalizer function to the user in %a1.\n\
165 " PCREL_OP ("lea", "_dl_fini", "%a1", "%a1", "%pc") "\n\
166 | Initialize %fp with the stack pointer.\n\
168 | Jump to the user's entry point.\n\
170 .size _dl_start_user, . - _dl_start_user\n\
173 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
174 TLS variable, so undefined references should not be allowed to
176 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
177 of the main executable's symbols, as for a COPY reloc. */
178 #define elf_machine_type_class(type) \
179 ((((type) == R_68K_JMP_SLOT \
180 || (type) == R_68K_TLS_DTPMOD32 \
181 || (type) == R_68K_TLS_DTPREL32 \
182 || (type) == R_68K_TLS_TPREL32) * ELF_RTYPE_CLASS_PLT) \
183 | (((type) == R_68K_COPY) * ELF_RTYPE_CLASS_COPY))
185 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
186 #define ELF_MACHINE_JMP_SLOT R_68K_JMP_SLOT
188 static inline Elf32_Addr
189 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
190 const ElfW(Sym
) *refsym
, const ElfW(Sym
) *sym
,
191 const Elf32_Rela
*reloc
,
192 Elf32_Addr
*reloc_addr
, Elf32_Addr value
)
194 return *reloc_addr
= value
;
197 /* Return the final value of a plt relocation. On the m68k the JMP_SLOT
198 relocation ignores the addend. */
199 static inline Elf32_Addr
200 elf_machine_plt_value (struct link_map
*map
, const Elf32_Rela
*reloc
,
206 /* Names of the architecture-specific auditing callback functions. */
207 #define ARCH_LA_PLTENTER m68k_gnu_pltenter
208 #define ARCH_LA_PLTEXIT m68k_gnu_pltexit
210 #endif /* !dl_machine_h */
214 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
215 MAP is the object containing the reloc. */
217 static inline void __attribute__ ((unused
, always_inline
))
218 elf_machine_rela (struct link_map
*map
, struct r_scope_elem
*scope
[],
219 const Elf32_Rela
*reloc
, const Elf32_Sym
*sym
,
220 const struct r_found_version
*version
,
221 void *const reloc_addr_arg
, int skip_ifunc
)
223 Elf32_Addr
*const reloc_addr
= reloc_addr_arg
;
224 const unsigned int r_type
= ELF32_R_TYPE (reloc
->r_info
);
226 if (__builtin_expect (r_type
== R_68K_RELATIVE
, 0))
227 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
230 const Elf32_Sym
*const refsym
= sym
;
231 struct link_map
*sym_map
= RESOLVE_MAP (map
, scope
, &sym
, version
,
233 Elf32_Addr value
= SYMBOL_ADDRESS (sym_map
, sym
, true);
239 /* This can happen in trace mode if an object could not be
242 if (sym
->st_size
> refsym
->st_size
243 || (sym
->st_size
< refsym
->st_size
&& GLRO(dl_verbose
)))
247 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
249 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
250 RTLD_PROGNAME
, strtab
+ refsym
->st_name
);
252 memcpy (reloc_addr_arg
, (void *) value
,
253 MIN (sym
->st_size
, refsym
->st_size
));
260 *(char *) reloc_addr
= value
+ reloc
->r_addend
;
263 *(short *) reloc_addr
= value
+ reloc
->r_addend
;
266 *reloc_addr
= value
+ reloc
->r_addend
;
270 = value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
273 *(short *) reloc_addr
274 = value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
277 *reloc_addr
= value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
279 #ifndef RTLD_BOOTSTRAP
280 case R_68K_TLS_DTPMOD32
:
281 /* Get the information from the link map returned by the
284 *reloc_addr
= sym_map
->l_tls_modid
;
286 case R_68K_TLS_DTPREL32
:
288 *reloc_addr
= TLS_DTPREL_VALUE (sym
, reloc
);
290 case R_68K_TLS_TPREL32
:
293 CHECK_STATIC_TLS (map
, sym_map
);
294 *reloc_addr
= TLS_TPREL_VALUE (sym_map
, sym
, reloc
);
297 #endif /* !RTLD_BOOTSTRAP */
298 case R_68K_NONE
: /* Alright, Wilbur. */
301 _dl_reloc_bad_type (map
, r_type
, 0);
307 static inline void __attribute__ ((unused
, always_inline
))
308 elf_machine_rela_relative (Elf32_Addr l_addr
, const Elf32_Rela
*reloc
,
309 void *const reloc_addr_arg
)
311 Elf32_Addr
*const reloc_addr
= reloc_addr_arg
;
312 *reloc_addr
= l_addr
+ reloc
->r_addend
;
315 static inline void __attribute__ ((unused
, always_inline
))
316 elf_machine_lazy_rel (struct link_map
*map
, struct r_scope_elem
*scope
[],
317 Elf32_Addr l_addr
, const Elf32_Rela
*reloc
,
320 Elf32_Addr
*const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
321 if (ELF32_R_TYPE (reloc
->r_info
) == R_68K_JMP_SLOT
)
322 *reloc_addr
+= l_addr
;
324 _dl_reloc_bad_type (map
, ELF32_R_TYPE (reloc
->r_info
), 1);
327 #endif /* RESOLVE_MAP */