1 /* Machine-dependent ELF dynamic relocation inline functions. m68k version.
2 Copyright (C) 1996 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 Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 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 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
18 Cambridge, MA 02139, USA. */
20 #define ELF_MACHINE_NAME "m68k"
27 /* Return nonzero iff E_MACHINE is compatible with the running host. */
29 elf_machine_matches_host (Elf32_Half e_machine
)
41 /* Return the run-time address of the _GLOBAL_OFFSET_TABLE_.
42 Must be inlined in a function which uses global data. */
43 static inline Elf32_Addr
*
44 elf_machine_got (void)
46 register Elf32_Addr
*got
asm ("%a5");
51 /* Return the run-time load address of the shared object. */
52 static inline Elf32_Addr
53 elf_machine_load_address (void)
56 asm ("here: lea here(%%pc), %0\n"
62 /* The `subl' insn above will contain an R_68K_RELATIVE relocation
63 entry intended to insert the run-time address of the label `here'.
64 This will be the first relocation in the text of the dynamic
65 linker; we skip it to avoid trying to modify read-only text in this
67 #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) \
68 ((dynamic_info)[DT_RELA]->d_un.d_ptr += sizeof (Elf32_Rela), \
69 (dynamic_info)[DT_RELASZ]->d_un.d_val -= sizeof (Elf32_Rela))
71 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
72 MAP is the object containing the reloc. */
75 elf_machine_rela (struct link_map
*map
,
76 const Elf32_Rela
*reloc
, const Elf32_Sym
*sym
,
77 Elf32_Addr (*resolve
) (const Elf32_Sym
**ref
,
78 Elf32_Addr reloc_addr
,
81 Elf32_Addr
*const reloc_addr
= (void *) (map
->l_addr
+ reloc
->r_offset
);
84 switch (ELF32_R_TYPE (reloc
->r_info
))
87 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
88 memcpy (reloc_addr
, (void *) (loadbase
+ sym
->st_value
), sym
->st_size
);
91 loadbase
= (resolve
? (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0) :
92 /* RESOLVE is null during bootstrap relocation. */
94 *reloc_addr
= sym
? (loadbase
+ sym
->st_value
) : 0;
97 loadbase
= (resolve
? (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 1) :
98 /* RESOLVE is null during bootstrap relocation. */
100 *reloc_addr
= sym
? (loadbase
+ sym
->st_value
) : 0;
103 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
104 *(char *) reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
108 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
109 *(short *) reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
113 loadbase
= (resolve
? (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0) :
114 /* RESOLVE is null during bootstrap relocation. */
116 *reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
120 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
123 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
124 *(char *) reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
126 - (Elf32_Addr
) reloc_addr
);
129 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
130 *(short *) reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
132 - (Elf32_Addr
) reloc_addr
);
135 loadbase
= (*resolve
) (&sym
, (Elf32_Addr
) reloc_addr
, 0);
136 *reloc_addr
= ((sym
? (loadbase
+ sym
->st_value
) : 0)
138 - (Elf32_Addr
) reloc_addr
);
140 case R_68K_NONE
: /* Alright, Wilbur. */
143 assert (! "unexpected dynamic reloc type");
149 elf_machine_lazy_rel (struct link_map
*map
, const Elf32_Rela
*reloc
)
151 Elf32_Addr
*const reloc_addr
= (void *) (map
->l_addr
+ reloc
->r_offset
);
152 switch (ELF32_R_TYPE (reloc
->r_info
))
157 *reloc_addr
+= map
->l_addr
;
160 assert (! "unexpected PLT reloc type");
165 /* Nonzero iff TYPE describes relocation of a PLT entry, so
166 PLT entries should not be allowed to define the value. */
167 #define elf_machine_pltrel_p(type) ((type) == R_68K_JMP_SLOT)
169 /* The m68k never uses Elf32_Rel relocations. */
170 #define ELF_MACHINE_NO_REL 1
173 /* Set up the loaded object described by L so its unrelocated PLT
174 entries will jump to the on-demand fixup code in dl-runtime.c. */
177 elf_machine_runtime_setup (struct link_map
*l
, int lazy
)
180 extern void _dl_runtime_resolve (Elf32_Word
);
182 if (l
->l_info
[DT_JMPREL
] && lazy
)
184 /* The GOT entries for functions in the PLT have not yet been
185 filled in. Their initial contents will arrange when called
186 to push an offset into the .rela.plt section, push
187 _GLOBAL_OFFSET_TABLE_[1], and then jump to
188 _GLOBAL_OFFSET_TABLE_[2]. */
189 got
= (Elf32_Addr
*) (l
->l_addr
+ l
->l_info
[DT_PLTGOT
]->d_un
.d_ptr
);
190 got
[1] = (Elf32_Addr
) l
; /* Identify this shared object. */
191 /* This function will get called to fix up the GOT entry
192 indicated by the offset on the stack, and then jump to the
194 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
197 /* This code is used in dl-runtime.c to call the `fixup' function
198 and then redirect to the address it returns. */
199 #define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
200 | Trampoline for _dl_runtime_resolver
201 .globl _dl_runtime_resolve
202 .type _dl_runtime_resolve, @function
204 | Save %a0 (struct return address) and %a1.
207 | Call the real address resolver.
209 | Restore register %a0 and %a1.
214 | Call real function.
216 .size _dl_runtime_resolve, . - _dl_runtime_resolve
218 #define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0, long int save_a1
219 /* The PLT uses Elf32_Rela relocs. */
220 #define elf_machine_relplt elf_machine_rela
224 /* Mask identifying addresses reserved for the user program,
225 where the dynamic linker should not map anything. */
226 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
228 /* Initial entry point code for the dynamic linker.
229 The C function `_dl_start' is the real entry point;
230 its return value is the user program's entry point. */
232 #define RTLD_START asm ("\
235 .globl _dl_start_user
241 | Save the user entry point address in %a4.
243 | Point %a5 at the GOT.
244 lea _GLOBAL_OFFSET_TABLE_@GOTPC(%pc), %a5
245 | See if we were run as a command with the executable file
246 | name as an extra leading argument.
247 move.l ([_dl_skip_args@GOT, %a5]), %d0
249 | Pop the original argument count
251 | Subtract _dl_skip_args from it.
253 | Adjust the stack pointer to skip _dl_skip_args words.
254 lea (%sp, %d0*4), %sp
255 | Push back the modified argument count.
257 0: | Push _dl_default_scope[2] as argument in _dl_init_next call below.
258 move.l ([_dl_default_scope@GOT, %a5]), %d2
259 0: move.l (%d2, 8), -(%sp)
260 | Call _dl_init_next to return the address of an initializer
262 bsr.l _dl_init_next@PLTPC
263 add.l #4, %sp | Pop argument.
264 | Check for zero return, when out of initializers.
267 | Call the shared object initializer function.
268 | NOTE: We depend only on the registers (%d2, %a4 and %a5)
269 | and the return address pushed by this call;
270 | the initializer is called with the stack just
271 | as it appears on entry, and it is free to move
272 | the stack around, as long as it winds up jumping to
273 | the return address on the top of the stack.
276 | Loop to call _dl_init_next for the next initializer.
278 1: | Pass our finalizer function to the user in %a1.
279 move.l _dl_fini@GOT(%a5), %a1
280 | Initialize %fp with the stack pointer.
282 | Jump to the user's entry point.