1 /* Machine-dependent ELF dynamic relocation inline functions. m68k version.
2 Copyright (C) 1996-2001, 2002 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, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23 #define ELF_MACHINE_NAME "m68k"
25 #include <sys/param.h>
27 /* Return nonzero iff ELF header is compatible with the running host. */
29 elf_machine_matches_host (const Elf32_Ehdr
*ehdr
)
31 return ehdr
->e_machine
== EM_68K
;
35 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
36 first element of the GOT. This must be inlined in a function which
38 static inline Elf32_Addr
39 elf_machine_dynamic (void)
41 register Elf32_Addr
*got
asm ("%a5");
46 /* Return the run-time load address of the shared object. */
47 static inline Elf32_Addr
48 elf_machine_load_address (void)
51 asm ("lea _dl_start(%%pc), %0\n\t"
52 "sub.l _dl_start@GOT.w(%%a5), %0"
58 /* Set up the loaded object described by L so its unrelocated PLT
59 entries will jump to the on-demand fixup code in dl-runtime.c. */
62 elf_machine_runtime_setup (struct link_map
*l
, int lazy
, int profile
)
65 extern void _dl_runtime_resolve (Elf32_Word
);
66 extern void _dl_runtime_profile (Elf32_Word
);
68 if (l
->l_info
[DT_JMPREL
] && lazy
)
70 /* The GOT entries for functions in the PLT have not yet been
71 filled in. Their initial contents will arrange when called
72 to push an offset into the .rela.plt section, push
73 _GLOBAL_OFFSET_TABLE_[1], and then jump to
74 _GLOBAL_OFFSET_TABLE_[2]. */
75 got
= (Elf32_Addr
*) D_PTR (l
, l_info
[DT_PLTGOT
]);
76 got
[1] = (Elf32_Addr
) l
; /* Identify this shared object. */
78 /* The got[2] entry contains the address of a function which gets
79 called to get the address of a so far unresolved function and
80 jump to it. The profiling extension of the dynamic linker allows
81 to intercept the calls to collect information. In this case we
82 don't store the address in the GOT so that all future calls also
83 end in this function. */
86 got
[2] = (Elf32_Addr
) &_dl_runtime_profile
;
88 if (_dl_name_match_p (GL(dl_profile
), l
))
90 /* This is the object we are looking for. Say that we really
91 want profiling and the timers are started. */
92 GL(dl_profile_map
) = l
;
96 /* This function will get called to fix up the GOT entry indicated by
97 the offset on the stack, and then jump to the resolved address. */
98 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
104 /* This code is used in dl-runtime.c to call the `fixup' function
105 and then redirect to the address it returns. */
106 #define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \
107 "| Trampoline for " #fixup_name "\n\
108 .globl " #tramp_name "\n\
109 .type " #tramp_name ", @function\n\
111 | Save %a0 (struct return address) and %a1.\n\
112 move.l %a0, -(%sp)\n\
113 move.l %a1, -(%sp)\n\
114 | Call the real address resolver.\n\
115 jbsr " #fixup_name "\n\
116 | Restore register %a0 and %a1.\n\
117 move.l (%sp)+, %a1\n\
118 move.l (%sp)+, %a0\n\
121 | Call real function.\n\
123 .size " #tramp_name ", . - " #tramp_name "\n"
125 #define ELF_MACHINE_RUNTIME_TRAMPOLINE \
126 asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
127 TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup));
129 #define ELF_MACHINE_RUNTIME_TRAMPOLINE \
130 asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
131 ".globl _dl_runtime_profile\n" \
132 ".set _dl_runtime_profile, _dl_runtime_resolve");
134 #define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0, long int save_a1
137 /* Mask identifying addresses reserved for the user program,
138 where the dynamic linker should not map anything. */
139 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
141 /* Initial entry point code for the dynamic linker.
142 The C function `_dl_start' is the real entry point;
143 its return value is the user program's entry point. */
145 #define RTLD_START asm ("\
148 .type _start,@function\n\
150 move.l %sp, -(%sp)\n\
155 .globl _dl_start_user\n\
156 .type _dl_start_user,@function\n\
158 | Save the user entry point address in %a4.\n\
160 | Point %a5 at the GOT.\n\
161 lea _GLOBAL_OFFSET_TABLE_@GOTPC(%pc), %a5\n\
162 | Remember the highest stack address.\n\
163 move.l %sp, ([__libc_stack_end@GOT.w, %a5])\n\
164 | See if we were run as a command with the executable file\n\
165 | name as an extra leading argument.\n\
166 move.l ([_dl_skip_args@GOT.w, %a5]), %d0\n\
167 | Pop the original argument count\n\
168 move.l (%sp)+, %d1\n\
169 | Subtract _dl_skip_args from it.\n\
171 | Adjust the stack pointer to skip _dl_skip_args words.\n\
172 lea (%sp, %d0*4), %sp\n\
173 | Push back the modified argument count.\n\
174 move.l %d1, -(%sp)\n\
175 # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
178 move.l %d1, -(%sp)\n\
179 move.l ([_rtld_local@GOT.w, %a5]), -(%sp)\n\
180 jbsr _dl_init_internal@PLTPC\n\
183 | Pass our finalizer function to the user in %a1.\n\
184 move.l _dl_fini@GOT.w(%a5), %a1\n\
185 | Initialize %fp with the stack pointer.\n\
187 | Jump to the user's entry point.\n\
189 .size _dl_start_user, . - _dl_start_user\n\
192 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
193 PLT entries should not be allowed to define the value.
194 ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
195 of the main executable's symbols, as for a COPY reloc. */
196 #define elf_machine_type_class(type) \
197 ((((type) == R_68K_JMP_SLOT) * ELF_RTYPE_CLASS_PLT) \
198 | (((type) == R_68K_COPY) * ELF_RTYPE_CLASS_COPY))
200 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
201 #define ELF_MACHINE_JMP_SLOT R_68K_JMP_SLOT
203 /* The m68k never uses Elf32_Rel relocations. */
204 #define ELF_MACHINE_NO_REL 1
206 static inline Elf32_Addr
207 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
208 const Elf32_Rela
*reloc
,
209 Elf32_Addr
*reloc_addr
, Elf32_Addr value
)
211 return *reloc_addr
= value
;
214 /* Return the final value of a plt relocation. On the m68k the JMP_SLOT
215 relocation ignores the addend. */
216 static inline Elf32_Addr
217 elf_machine_plt_value (struct link_map
*map
, const Elf32_Rela
*reloc
,
223 #endif /* !dl_machine_h */
227 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
228 MAP is the object containing the reloc. */
231 elf_machine_rela (struct link_map
*map
, const Elf32_Rela
*reloc
,
232 const Elf32_Sym
*sym
, const struct r_found_version
*version
,
233 Elf32_Addr
*const reloc_addr
)
235 const unsigned int r_type
= ELF32_R_TYPE (reloc
->r_info
);
237 if (__builtin_expect (r_type
== R_68K_RELATIVE
, 0))
238 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
241 const Elf32_Sym
*const refsym
= sym
;
242 Elf32_Addr value
= RESOLVE (&sym
, version
, r_type
);
244 value
+= sym
->st_value
;
250 /* This can happen in trace mode if an object could not be
253 if (sym
->st_size
> refsym
->st_size
254 || (sym
->st_size
< refsym
->st_size
&& GL(dl_verbose
)))
258 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
260 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
261 rtld_progname
?: "<program name unknown>",
262 strtab
+ refsym
->st_name
);
264 memcpy (reloc_addr
, (void *) value
, MIN (sym
->st_size
,
272 *(char *) reloc_addr
= value
+ reloc
->r_addend
;
275 *(short *) reloc_addr
= value
+ reloc
->r_addend
;
278 *reloc_addr
= value
+ reloc
->r_addend
;
282 = value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
285 *(short *) reloc_addr
286 = value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
289 *reloc_addr
= value
+ reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
291 case R_68K_NONE
: /* Alright, Wilbur. */
294 _dl_reloc_bad_type (map
, r_type
, 0);
301 elf_machine_rela_relative (Elf32_Addr l_addr
, const Elf32_Rela
*reloc
,
302 Elf32_Addr
*const reloc_addr
)
304 *reloc_addr
= l_addr
+ reloc
->r_addend
;
308 elf_machine_lazy_rel (struct link_map
*map
,
309 Elf32_Addr l_addr
, const Elf32_Rela
*reloc
)
311 Elf32_Addr
*const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
312 if (ELF32_R_TYPE (reloc
->r_info
) == R_68K_JMP_SLOT
)
313 *reloc_addr
+= l_addr
;
315 _dl_reloc_bad_type (map
, ELF32_R_TYPE (reloc
->r_info
), 1);