1 /* Machine-dependent ELF dynamic relocation inline functions. ARM version.
2 Copyright (C) 1995, 1996, 1997, 1998 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 not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
23 #define ELF_MACHINE_NAME "ARM"
25 #include <sys/param.h>
29 /* Return nonzero iff E_MACHINE is compatible with the running host. */
30 static inline int __attribute__ ((unused
))
31 elf_machine_matches_host (Elf32_Half e_machine
)
43 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
44 first element of the GOT. This must be inlined in a function which
46 static inline Elf32_Addr
__attribute__ ((unused
))
47 elf_machine_dynamic (void)
49 register Elf32_Addr
*got
asm ("r10");
54 /* Return the run-time load address of the shared object. */
56 static inline Elf32_Addr
__attribute__ ((unused
))
57 elf_machine_load_address (void)
66 .L1: .word _dl_start(GOT)
67 .L3: .word _dl_start(GOTOFF)
69 : "=r" (addr
) : : "ip", "r3");
74 /* Set up the loaded object described by L so its unrelocated PLT
75 entries will jump to the on-demand fixup code in dl-runtime.c. */
77 static inline int __attribute__ ((unused
))
78 elf_machine_runtime_setup (struct link_map
*l
, int lazy
, int profile
)
81 extern void _dl_runtime_resolve (Elf32_Word
);
82 extern void _dl_runtime_profile (Elf32_Word
);
84 if (l
->l_info
[DT_JMPREL
] && lazy
)
86 /* patb: this is different than i386 */
87 /* The GOT entries for functions in the PLT have not yet been filled
88 in. Their initial contents will arrange when called to push an
89 index into the .got section, load ip with &_GLOBAL_OFFSET_TABLE_[3],
90 and then jump to _GLOBAL_OFFSET_TABLE[2]. */
91 got
= (Elf32_Addr
*) (l
->l_addr
+ l
->l_info
[DT_PLTGOT
]->d_un
.d_ptr
);
92 got
[1] = (Elf32_Addr
) l
; /* Identify this shared object. */
94 /* The got[2] entry contains the address of a function which gets
95 called to get the address of a so far unresolved function and
96 jump to it. The profiling extension of the dynamic linker allows
97 to intercept the calls to collect information. In this case we
98 don't store the address in the GOT so that all future calls also
99 end in this function. */
102 //got[2] = (Elf32_Addr) &_dl_runtime_profile;
103 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
104 /* Say that we really want profiling and the timers are started. */
108 /* This function will get called to fix up the GOT entry indicated by
109 the offset on the stack, and then jump to the resolved address. */
110 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
115 /* This code is used in dl-runtime.c to call the `fixup' function
116 and then redirect to the address it returns. */
117 // macro for handling PIC situation....
119 #define CALL_ROUTINE(x) " ldr sl,0f
125 0: .word _GLOBAL_OFFSET_TABLE_ - 1b - 4
126 2: .word " #x "(GOTOFF)
129 #define CALL_ROUTINE(x) " bl " #x
133 # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
135 .globl _dl_runtime_resolve
136 .type _dl_runtime_resolve, #function
140 @ stack[0] contains the return address from this call
141 @ ip contains &GOT[n+3] (pointer to function)
142 @ lr points to &GOT[2]
144 @ save almost everything; lr is already on the stack
145 stmdb sp!,{r0-r3,sl,fp}
147 @ prepare to call fixup()
148 @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
153 @ get pointer to linker struct
157 " CALL_ROUTINE(fixup) "
163 ldmia sp!,{r0-r3,sl,fp,lr}
165 @ jump to the newly found address
168 .size _dl_runtime_resolve, .-_dl_runtime_resolve
170 .globl _dl_runtime_profile
171 .type _dl_runtime_profile, #function
174 @ save almost everything; lr is already on the stack
175 stmdb sp!,{r0-r3,sl,fp}
177 @ prepare to call fixup()
178 @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
183 @ get pointer to linker struct
186 @ call profiling fixup routine
187 " CALL_ROUTINE(profile_fixup) "
193 ldmia sp!,{r0-r3,sl,fp,lr}
195 @ jump to the newly found address
198 .size _dl_runtime_resolve, .-_dl_runtime_resolve
202 # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
204 .globl _dl_runtime_resolve
205 .globl _dl_runtime_profile
206 .type _dl_runtime_resolve, #function
207 .type _dl_runtime_profile, #function
212 @ stack[0] contains the return address from this call
213 @ ip contains &GOT[n+3] (pointer to function)
214 @ lr points to &GOT[2]
216 @ save almost everything; return add is already on the stack
217 stmdb sp!,{r0-r3,sl,fp}
219 @ prepare to call fixup()
220 @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
225 @ get pointer to linker struct
228 @ call profiling fixup routine
229 " CALL_ROUTINE(fixup) "
235 ldmia sp!,{r0-r3,sl,fp,lr}
237 @ jump to the newly found address
240 .size _dl_runtime_profile, .-_dl_runtime_profile
245 /* Mask identifying addresses reserved for the user program,
246 where the dynamic linker should not map anything. */
247 #define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
249 /* Initial entry point code for the dynamic linker.
250 The C function `_dl_start' is the real entry point;
251 its return value is the user program's entry point. */
253 #define RTLD_START asm ("\
256 .globl _dl_start_user
258 @ at start time, all the args are on the stack
261 @ returns user entry point in r0
264 @ we are PIC code, so get global offset table
268 @ Store the highest stack address
272 @ See if we were run as a command with the executable file
273 @ name as an extra leading argument.
276 @ get the original arg count
278 @ subtract _dl_skip_args from it
280 @ adjust the stack pointer to skip them
281 add sp, sp, r1, lsl #2
282 @ store the new argc in the new stack location
285 @ now we enter a _dl_init_next loop
289 @ call _dl_init_next to get the address of an initalizer
291 bl _dl_init_next(PLT)
294 @ call the shared-object initializer
295 @ during this call, the stack may get moved around
298 @ go back and look for another initializer
300 1: @ clear the startup flag
301 ldr r2, .L_STARTUP_FLAG
303 @ we know r0==0 at this point
305 @ load the finalizer function
308 @ jump to the user_s entry point
311 .word _GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4 \n\
313 .word _dl_skip_args(GOTOFF) \n\
315 .word _dl_default_scope(GOT) \n\
317 .word _dl_starting_up(GOT)
321 .word __libc_stack_end(GOT)
325 /* Nonzero iff TYPE should not be allowed to resolve to one of
326 the main executable's symbols, as for a COPY reloc. */
327 #define elf_machine_lookup_noexec_p(type) ((type) == R_ARM_COPY)
329 /* Nonzero iff TYPE describes relocation of a PLT entry, so
330 PLT entries should not be allowed to define the value. */
331 #define elf_machine_lookup_noplt_p(type) ((type) == R_ARM_JUMP_SLOT)
333 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
334 #define ELF_MACHINE_JMP_SLOT R_ARM_JUMP_SLOT
336 /* The ARM never uses Elf32_Rela relocations. */
337 #define ELF_MACHINE_NO_RELA 1
339 /* We define an initialization functions. This is called very early in
341 #define DL_PLATFORM_INIT dl_platform_init ()
343 extern const char *_dl_platform
;
345 static inline void __attribute__ ((unused
))
346 dl_platform_init (void)
348 if (_dl_platform
== NULL
)
350 This is where processors could be distinguished arm2, arm6, sa110, etc */
351 _dl_platform
= "ARM";
355 elf_machine_fixup_plt (struct link_map
*map
, const Elf32_Rel
*reloc
,
356 Elf32_Addr
*reloc_addr
, Elf32_Addr value
)
361 /* Return the final value of a plt relocation. */
362 static inline Elf32_Addr
363 elf_machine_plt_value (struct link_map
*map
, const Elf32_Rel
*reloc
,
369 #endif /* !dl_machine_h */
373 extern char **_dl_argv
;
375 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
376 MAP is the object containing the reloc. */
379 elf_machine_rel (struct link_map
*map
, const Elf32_Rel
*reloc
,
380 const Elf32_Sym
*sym
, const struct r_found_version
*version
,
381 Elf32_Addr
*const reloc_addr
)
383 if (ELF32_R_TYPE (reloc
->r_info
) == R_ARM_RELATIVE
)
385 #ifndef RTLD_BOOTSTRAP
386 if (map
!= &_dl_rtld_map
) /* Already done in rtld itself. */
388 *reloc_addr
+= map
->l_addr
;
390 else if (ELF32_R_TYPE (reloc
->r_info
) != R_ARM_NONE
)
392 const Elf32_Sym
*const refsym
= sym
;
393 Elf32_Addr value
= RESOLVE (&sym
, version
, ELF32_R_TYPE (reloc
->r_info
));
395 value
+= sym
->st_value
;
397 switch (ELF32_R_TYPE (reloc
->r_info
))
401 /* This can happen in trace mode if an object could not be
404 if (sym
->st_size
> refsym
->st_size
405 || (_dl_verbose
&& sym
->st_size
< refsym
->st_size
))
409 strtab
= ((const char *) map
->l_addr
410 + map
->l_info
[DT_STRTAB
]->d_un
.d_ptr
);
411 _dl_sysdep_error (_dl_argv
[0] ?: "<program name unknown>",
412 ": Symbol `", strtab
+ refsym
->st_name
,
413 "' has different size in shared object, "
414 "consider re-linking\n", NULL
);
416 memcpy (reloc_addr
, (void *) value
, MIN (sym
->st_size
,
420 case R_ARM_JUMP_SLOT
:
425 #ifndef RTLD_BOOTSTRAP
426 /* This is defined in rtld.c, but nowhere in the static
427 libc.a; make the reference weak so static programs can
428 still link. This declaration cannot be done when
429 compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because
430 rtld.c contains the common defn for _dl_rtld_map, which
431 is incompatible with a weak decl in the same file. */
432 weak_extern (_dl_rtld_map
);
433 if (map
== &_dl_rtld_map
)
434 /* Undo the relocation done here during bootstrapping.
435 Now we will relocate it anew, possibly using a
436 binding found in the user program or a loaded library
437 rather than the dynamic linker's built-in definitions
438 used while loading those libraries. */
439 value
-= map
->l_addr
+ refsym
->st_value
;
441 *reloc_addr
+= value
;
445 assert (! "unexpected dynamic reloc type");
452 elf_machine_lazy_rel (struct link_map
*map
, const Elf32_Rel
*reloc
)
454 Elf32_Addr
*const reloc_addr
= (void *) (map
->l_addr
+ reloc
->r_offset
);
455 switch (ELF32_R_TYPE (reloc
->r_info
))
457 case R_ARM_JUMP_SLOT
:
458 *reloc_addr
+= map
->l_addr
;
461 assert (! "unexpected PLT reloc type");