1 /* Machine-dependent ELF dynamic relocation inline functions. S390 Version.
2 Copyright (C) 2000 Free Software Foundation, Inc.
3 Contributed by Carl Pederson & Martin Schwidefsky.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If
18 not, write to the Free Software Foundation, Inc.,
19 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
25 #define ELF_MACHINE_NAME "s390"
27 #include <sys/param.h>
32 /* Return nonzero iff ELF header is compatible with the running host. */
34 elf_machine_matches_host (const Elf32_Ehdr
*ehdr
)
36 return ehdr
->e_machine
== EM_S390
;
40 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
41 first element of the GOT. This must be inlined in a function which
44 static inline Elf32_Addr
45 elf_machine_dynamic (void)
47 register Elf32_Addr
*got
;
50 "1: .long _GLOBAL_OFFSET_TABLE_-1b\n"
52 : "=&a" (got
) : : "0" );
58 /* Return the run-time load address of the shared object. */
59 static inline Elf32_Addr
60 elf_machine_load_address (void)
65 "1: .long _GLOBAL_OFFSET_TABLE_ - 1b\n"
66 " .long _dl_start - 1b - 0x80000000\n"
70 " sl %0,_dl_start@GOT12(1)"
71 : "=&d" (addr
) : : "1" );
75 /* Set up the loaded object described by L so its unrelocated PLT
76 entries will jump to the on-demand fixup code in dl-runtime.c. */
78 static inline int __attribute__ ((unused
))
79 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 /* The GOT entries for functions in the PLT have not yet been filled
87 in. Their initial contents will arrange when called to push an
88 offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
89 and then jump to _GLOBAL_OFFSET_TABLE[2]. */
91 got
= (Elf32_Addr
*) D_PTR (l
, l_info
[DT_PLTGOT
]);
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. */
100 if (__builtin_expect (profile
, 0))
102 got
[2] = (Elf32_Addr
) &_dl_runtime_profile
;
104 if (_dl_name_match_p (_dl_profile
, l
))
105 /* This is the object we are looking for. Say that we really
106 want profiling and the timers are started. */
110 /* This function will get called to fix up the GOT entry indicated by
111 the offset on the stack, and then jump to the resolved address. */
112 got
[2] = (Elf32_Addr
) &_dl_runtime_resolve
;
118 /* This code is used in dl-runtime.c to call the `fixup' function
119 and then redirect to the address it returns. */
122 Arguments are in register.
123 r2 - r7 holds the original parameters for the function call, fixup
124 and trampoline code use r0-r5 and r14-15. For the correct function
125 call r2-r5 and r14-15 must be restored.
126 Arguments from the PLT are stored at 24(r15) and 28(r15)
127 and must be moved to r2 and r3 for the fixup call (see elf32-s390.c
128 in the binutils for the PLT code).
129 Fixup function address in r2.
132 #define ELF_MACHINE_RUNTIME_TRAMPOLINE \
135 .globl _dl_runtime_resolve\n\
136 .type _dl_runtime_resolve, @function\n\
138 _dl_runtime_resolve:\n\
145 # load args saved by PLT\n\
150 bas 14,0(14,1) # call fixup\n\
151 lr 1,2 # function addr returned in r2\n\
152 # restore registers\n\
158 .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
160 .globl _dl_runtime_profile\n\
161 .type _dl_runtime_profile, @function\n\
163 _dl_runtime_profile:\n\
170 # load args saved by PLT\n\
172 # load return address as third parameter\n\
177 bas 14,0(14,1) # call fixup\n\
178 lr 1,2 # function addr returned in r2\n\
179 # restore registers\n\
184 1: .long profile_fixup-1b\n\
185 .size _dl_runtime_profile, .-_dl_runtime_profile\n\
188 #define ELF_MACHINE_RUNTIME_TRAMPOLINE \
191 .globl _dl_runtime_resolve\n\
192 .globl _dl_runtime_profile\n\
193 .type _dl_runtime_resolve, @function\n\
194 .type _dl_runtime_profile, @function\n\
196 _dl_runtime_resolve:\n\
197 _dl_runtime_profile:\n\
204 # load args saved by PLT\n\
206 # load return address as third parameter\n\
211 bas 14,0(14,1) # call fixup\n\
212 lr 1,2 # function addr returned in r2\n\
213 # restore registers\n\
219 .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
220 .size _dl_runtime_profile, .-_dl_runtime_profile\n\
224 /* The PLT uses Elf32_Rela relocs. */
225 #define elf_machine_relplt elf_machine_rela
227 /* Mask identifying addresses reserved for the user program,
228 where the dynamic linker should not map anything. */
229 #define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
231 /* Initial entry point code for the dynamic linker.
232 The C function `_dl_start' is the real entry point;
233 its return value is the user program's entry point. */
235 #define RTLD_START asm ("\n\
239 .globl _dl_start_user\n\
242 .L0: ahi %r13,.Llit-.L0\n\
244 # Alloc stack frame\n\
246 # Set the back chain to zero\n\
247 xc 0(4,%r15),0(%r15)\n\
248 # Call _dl_start with %r2 pointing to arg on stack\n\
249 l %r14,.Ladr1-.Llit(%r13)\n\
250 bas %r14,0(%r14,%r13) # call _dl_start\n\
252 # Save the user entry point address in %r8.\n\
254 # Point %r12 at the GOT.\n\
255 l %r12,.Ladr0-.Llit(%r13)\n\
257 # Store the highest stack address\n\
258 l %r1,__libc_stack_end@GOT(%r12)\n\
260 # See if we were run as a command with the executable file\n\
261 # name as an extra leading argument.\n\
262 l %r1,_dl_skip_args@GOT12(0,%r12)\n\
263 l %r1,0(%r1) # load _dl_skip_args\n\
264 # Get the original argument count.\n\
266 # Subtract _dl_skip_args from it.\n\
268 # Adjust the stack pointer to skip _dl_skip_args words.\n\
271 # Set the back chain to zero again\n\
272 xc 0(4,%r15),0(%r15)\n\
273 # Store back the modified argument count.\n\
275 # The special initializer gets called with the stack just\n\
276 # as the application's entry point will see it; it can\n\
277 # switch stacks if it moves these contents over.\n\
278 " RTLD_START_SPECIAL_INIT "\n\
279 # Call the function to run the initializers.\n\
280 # Load the parameters:\n\
281 # (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
282 l %r2,_dl_loaded@GOT(%r12)\n\
288 la %r5,104(%r5,%r15)\n\
289 l %r1,.Ladr4-.Llit(%r13)\n\
290 bas %r14,0(%r1,%r13)\n\
291 # Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
292 l %r14,_dl_fini@GOT(%r12)\n\
293 # Free stack frame\n\
295 # Jump to the user's entry point (saved in %r8).\n\
298 .Ladr0: .long _GLOBAL_OFFSET_TABLE_-.Llit\n\
299 .Ladr1: .long _dl_start-.Llit\n\
300 .Ladr4: .long _dl_init@PLT-.Llit\n\
303 #ifndef RTLD_START_SPECIAL_INIT
304 #define RTLD_START_SPECIAL_INIT /* nothing */
307 /* Nonzero iff TYPE describes relocation of a PLT entry, so
308 PLT entries should not be allowed to define the value. */
309 #define elf_machine_pltrel_p(type) ((type) == R_390_JMP_SLOT)
311 /* Nonzero iff TYPE should not be allowed to resolve to one of
312 the main executable's symbols, as for a COPY reloc. */
313 #define elf_machine_lookup_noexec_p(type) ((type) == R_390_COPY)
315 /* Nonzero iff TYPE describes relocation of a PLT entry, so
316 PLT entries should not be allowed to define the value. */
317 #define elf_machine_lookup_noplt_p(type) ((type) == R_390_JMP_SLOT)
319 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
320 #define ELF_MACHINE_JMP_SLOT R_390_JMP_SLOT
322 /* The S390 never uses Elf32_Rel relocations. */
323 #define ELF_MACHINE_NO_REL 1
325 /* The S390 overlaps DT_RELA and DT_PLTREL. */
326 #define ELF_MACHINE_PLTREL_OVERLAP 1
328 /* We define an initialization functions. This is called very early in
330 #define DL_PLATFORM_INIT dl_platform_init ()
332 extern const char *_dl_platform
;
334 static inline void __attribute__ ((unused
))
335 dl_platform_init (void)
337 if (_dl_platform
!= NULL
&& *_dl_platform
== '\0')
338 /* Avoid an empty string which would disturb us. */
342 static inline Elf32_Addr
343 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
344 const Elf32_Rela
*reloc
,
345 Elf32_Addr
*reloc_addr
, Elf32_Addr value
)
347 return *reloc_addr
= value
;
350 /* Return the final value of a plt relocation. */
351 static inline Elf32_Addr
352 elf_machine_plt_value (struct link_map
*map
, const Elf32_Rela
*reloc
,
358 #endif /* !dl_machine_h */
363 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
364 MAP is the object containing the reloc. */
367 elf_machine_rela (struct link_map
*map
, const Elf32_Rela
*reloc
,
368 const Elf32_Sym
*sym
, const struct r_found_version
*version
,
369 Elf32_Addr
*const reloc_addr
)
371 if (ELF32_R_TYPE (reloc
->r_info
) == R_390_RELATIVE
) {
372 #ifndef RTLD_BOOTSTRAP
373 if (map
!= &_dl_rtld_map
) /* Already done in rtld itself. */
375 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
377 else if (ELF32_R_TYPE (reloc
->r_info
) != R_390_NONE
)
379 const Elf32_Sym
*const refsym
= sym
;
380 Elf32_Addr value
= RESOLVE (&sym
, version
, ELF32_R_TYPE (reloc
->r_info
));
382 value
+= sym
->st_value
;
384 switch (ELF32_R_TYPE (reloc
->r_info
))
388 /* This can happen in trace mode if an object could not be
391 if (__builtin_expect (sym
->st_size
> refsym
->st_size
, 0)
392 || (__builtin_expect (sym
->st_size
< refsym
->st_size
, 0)
393 && __builtin_expect (_dl_verbose
, 0)))
397 strtab
= (const char *) D_PTR(map
,l_info
[DT_STRTAB
]);
398 _dl_sysdep_error (_dl_argv
[0] ?: "<program name unknown>",
399 ": Symbol `", strtab
+ refsym
->st_name
,
400 "' has different size in shared object, "
401 "consider re-linking\n", NULL
);
403 memcpy (reloc_addr
, (void *) value
, MIN (sym
->st_size
,
412 #ifndef RTLD_BOOTSTRAP
413 /* This is defined in rtld.c, but nowhere in the static
414 libc.a; make the reference weak so static programs can
415 still link. This declaration cannot be done when
416 compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because
417 rtld.c contains the common defn for _dl_rtld_map, which
418 is incompatible with a weak decl in the same file. */
419 weak_extern (_dl_rtld_map
);
420 if (map
== &_dl_rtld_map
)
421 /* Undo the relocation done here during bootstrapping.
422 Now we will relocate it anew, possibly using a
423 binding found in the user program or a loaded library
424 rather than the dynamic linker's built-in definitions
425 used while loading those libraries. */
426 value
-= map
->l_addr
+ refsym
->st_value
;
428 *reloc_addr
= value
+ reloc
->r_addend
;
433 *reloc_addr
= value
+reloc
->r_addend
- (Elf32_Addr
) reloc_addr
;
438 _dl_reloc_bad_type (map
, ELFW(R_TYPE
) (reloc
->r_info
), 0);
446 elf_machine_lazy_rel (struct link_map
*map
,
447 Elf32_Addr l_addr
, const Elf32_Rela
*reloc
)
449 Elf32_Addr
*const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
450 /* Check for unexpected PLT reloc type. */
451 if (__builtin_expect (ELF32_R_TYPE (reloc
->r_info
), R_390_JMP_SLOT
)
453 *reloc_addr
+= l_addr
;
455 _dl_reloc_bad_type (map
, ELFW(R_TYPE
) (reloc
->r_info
), 1);