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1 /* Machine-dependent ELF dynamic relocation inline functions.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
4 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
5 This file is part of the GNU C Library.
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <http://www.gnu.org/licenses/>. */
24 #define ELF_MACHINE_NAME "s390x"
26 #include <sys/param.h>
31 #define ELF_MACHINE_IRELATIVE R_390_IRELATIVE
33 /* This is an older, now obsolete value. */
34 #define EM_S390_OLD 0xA390
36 /* Return nonzero iff E_MACHINE is compatible with the running host. */
38 elf_machine_matches_host (const Elf64_Ehdr
*ehdr
)
40 return (ehdr
->e_machine
== EM_S390
|| ehdr
->e_machine
== EM_S390_OLD
)
41 && ehdr
->e_ident
[EI_CLASS
] == ELFCLASS64
;
44 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
45 first element of the GOT. This must be inlined in a function which
48 static inline Elf64_Addr
49 elf_machine_dynamic (void)
51 register Elf64_Addr
*got
;
53 asm( " larl %0,_GLOBAL_OFFSET_TABLE_\n"
54 : "=&a" (got
) : : "0" );
59 /* Return the run-time load address of the shared object. */
60 static inline Elf64_Addr
61 elf_machine_load_address (void)
65 asm( " larl %0,_dl_start\n"
66 " larl 1,_GLOBAL_OFFSET_TABLE_\n"
67 " lghi 2,_dl_start@GOT\n"
69 : "=&d" (addr
) : : "1", "2" );
73 /* Set up the loaded object described by L so its unrelocated PLT
74 entries will jump to the on-demand fixup code in dl-runtime.c. */
76 static inline int __attribute__ ((unused
))
77 elf_machine_runtime_setup (struct link_map
*l
, int lazy
, int profile
)
79 extern void _dl_runtime_resolve (Elf64_Word
);
80 extern void _dl_runtime_profile (Elf64_Word
);
82 if (l
->l_info
[DT_JMPREL
] && lazy
)
84 /* The GOT entries for functions in the PLT have not yet been filled
85 in. Their initial contents will arrange when called to push an
86 offset into the .rela.plt section, push _GLOBAL_OFFSET_TABLE_[1],
87 and then jump to _GLOBAL_OFFSET_TABLE[2]. */
89 got
= (Elf64_Addr
*) D_PTR (l
, l_info
[DT_PLTGOT
]);
90 /* If a library is prelinked but we have to relocate anyway,
91 we have to be able to undo the prelinking of .got.plt.
92 The prelinker saved us here address of .plt + 0x2e. */
95 l
->l_mach
.plt
= got
[1] + l
->l_addr
;
96 l
->l_mach
.gotplt
= (Elf64_Addr
) &got
[3];
98 got
[1] = (Elf64_Addr
) l
; /* Identify this shared object. */
100 /* The got[2] entry contains the address of a function which gets
101 called to get the address of a so far unresolved function and
102 jump to it. The profiling extension of the dynamic linker allows
103 to intercept the calls to collect information. In this case we
104 don't store the address in the GOT so that all future calls also
105 end in this function. */
106 if (__glibc_unlikely (profile
))
108 got
[2] = (Elf64_Addr
) &_dl_runtime_profile
;
110 if (GLRO(dl_profile
) != NULL
111 && _dl_name_match_p (GLRO(dl_profile
), l
))
112 /* This is the object we are looking for. Say that we really
113 want profiling and the timers are started. */
114 GL(dl_profile_map
) = l
;
117 /* This function will get called to fix up the GOT entry indicated by
118 the offset on the stack, and then jump to the resolved address. */
119 got
[2] = (Elf64_Addr
) &_dl_runtime_resolve
;
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 ("\n\
133 .globl _dl_start_user\n\
136 # Alloc stack frame\n\
138 # Set the back chain to zero\n\
139 xc 0(8,%r15),0(%r15)\n\
140 # Call _dl_start with %r2 pointing to arg on stack\n\
141 brasl %r14,_dl_start # call _dl_start\n\
143 # Save the user entry point address in %r8.\n\
145 # Point %r12 at the GOT.\n\
146 larl %r12,_GLOBAL_OFFSET_TABLE_\n\
147 # See if we were run as a command with the executable file\n\
148 # name as an extra leading argument.\n\
149 lghi %r1,_dl_skip_args@GOT\n\
150 lg %r1,0(%r1,%r12)\n\
151 lgf %r1,0(%r1) # load _dl_skip_args\n\
152 # Get the original argument count.\n\
154 # Subtract _dl_skip_args from it.\n\
156 # Adjust the stack pointer to skip _dl_skip_args words.\n\
159 # Set the back chain to zero again\n\
160 xc 0(8,%r15),0(%r15)\n\
161 # Store back the modified argument count.\n\
163 # The special initializer gets called with the stack just\n\
164 # as the application's entry point will see it; it can\n\
165 # switch stacks if it moves these contents over.\n\
166 " RTLD_START_SPECIAL_INIT "\n\
167 # Call the function to run the initializers.\n\
168 # Load the parameters:\n\
169 # (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
170 lghi %r2,_rtld_local@GOT\n\
171 lg %r2,0(%r2,%r12)\n\
177 la %r5,176(%r5,%r15)\n\
178 brasl %r14,_dl_init@PLT\n\
179 # Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
180 lghi %r14,_dl_fini@GOT\n\
181 lg %r14,0(%r14,%r12)\n\
182 # Free stack frame\n\
184 # Jump to the user's entry point (saved in %r8).\n\
188 #ifndef RTLD_START_SPECIAL_INIT
189 #define RTLD_START_SPECIAL_INIT /* nothing */
192 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
193 TLS variable, so undefined references should not be allowed to
195 ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
196 of the main executable's symbols, as for a COPY reloc. */
197 #define elf_machine_type_class(type) \
198 ((((type) == R_390_JMP_SLOT || (type) == R_390_TLS_DTPMOD \
199 || (type) == R_390_TLS_DTPOFF || (type) == R_390_TLS_TPOFF) \
200 * ELF_RTYPE_CLASS_PLT) \
201 | (((type) == R_390_COPY) * ELF_RTYPE_CLASS_COPY))
203 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
204 #define ELF_MACHINE_JMP_SLOT R_390_JMP_SLOT
206 /* The 64 bit S/390 never uses Elf64_Rel relocations. */
207 #define ELF_MACHINE_NO_REL 1
208 #define ELF_MACHINE_NO_RELA 0
210 /* We define an initialization functions. This is called very early in
212 #define DL_PLATFORM_INIT dl_platform_init ()
214 static inline void __attribute__ ((unused
))
215 dl_platform_init (void)
217 if (GLRO(dl_platform
) != NULL
&& *GLRO(dl_platform
) == '\0')
218 /* Avoid an empty string which would disturb us. */
219 GLRO(dl_platform
) = NULL
;
222 static inline Elf64_Addr
223 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
224 const Elf64_Rela
*reloc
,
225 Elf64_Addr
*reloc_addr
, Elf64_Addr value
)
227 return *reloc_addr
= value
;
230 /* Return the final value of a plt relocation. */
231 static inline Elf64_Addr
232 elf_machine_plt_value (struct link_map
*map
, const Elf64_Rela
*reloc
,
238 /* Names of the architecture-specific auditing callback functions. */
239 #define ARCH_LA_PLTENTER s390_64_gnu_pltenter
240 #define ARCH_LA_PLTEXIT s390_64_gnu_pltexit
242 #endif /* !dl_machine_h */
246 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
247 MAP is the object containing the reloc. */
250 __attribute__ ((always_inline
))
251 elf_machine_rela (struct link_map
*map
, const Elf64_Rela
*reloc
,
252 const Elf64_Sym
*sym
, const struct r_found_version
*version
,
253 void *const reloc_addr_arg
, int skip_ifunc
)
255 Elf64_Addr
*const reloc_addr
= reloc_addr_arg
;
256 const unsigned int r_type
= ELF64_R_TYPE (reloc
->r_info
);
258 #if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
259 if (__glibc_unlikely (r_type
== R_390_RELATIVE
))
261 # if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
262 /* This is defined in rtld.c, but nowhere in the static libc.a;
263 make the reference weak so static programs can still link.
264 This declaration cannot be done when compiling rtld.c
265 (i.e. #ifdef RTLD_BOOTSTRAP) because rtld.c contains the
266 common defn for _dl_rtld_map, which is incompatible with a
267 weak decl in the same file. */
269 weak_extern (GL(dl_rtld_map
));
271 if (map
!= &GL(dl_rtld_map
)) /* Already done in rtld itself. */
273 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
277 if (__glibc_unlikely (r_type
== R_390_NONE
))
281 #if !defined RTLD_BOOTSTRAP && !defined RESOLVE_CONFLICT_FIND_MAP
282 /* Only needed for R_390_COPY below. */
283 const Elf64_Sym
*const refsym
= sym
;
285 struct link_map
*sym_map
= RESOLVE_MAP (&sym
, version
, r_type
);
286 Elf64_Addr value
= sym
== NULL
? 0 : sym_map
->l_addr
+ sym
->st_value
;
289 && __builtin_expect (ELFW(ST_TYPE
) (sym
->st_info
) == STT_GNU_IFUNC
,
291 && __builtin_expect (sym
->st_shndx
!= SHN_UNDEF
, 1)
292 && __builtin_expect (!skip_ifunc
, 1))
293 value
= elf_ifunc_invoke (value
);
297 case R_390_IRELATIVE
:
298 value
= map
->l_addr
+ reloc
->r_addend
;
299 if (__glibc_likely (!skip_ifunc
))
300 value
= elf_ifunc_invoke (value
);
305 *reloc_addr
= value
+ reloc
->r_addend
;
308 #ifndef RESOLVE_CONFLICT_FIND_MAP
309 case R_390_TLS_DTPMOD
:
310 # ifdef RTLD_BOOTSTRAP
311 /* During startup the dynamic linker is always the module
313 XXX If this relocation is necessary move before RESOLVE
317 /* Get the information from the link map returned by the
320 *reloc_addr
= sym_map
->l_tls_modid
;
323 case R_390_TLS_DTPOFF
:
324 # ifndef RTLD_BOOTSTRAP
325 /* During relocation all TLS symbols are defined and used.
326 Therefore the offset is already correct. */
328 *reloc_addr
= sym
->st_value
+ reloc
->r_addend
;
331 case R_390_TLS_TPOFF
:
332 /* The offset is negative, forward from the thread pointer. */
333 # ifdef RTLD_BOOTSTRAP
334 *reloc_addr
= sym
->st_value
+ reloc
->r_addend
- map
->l_tls_offset
;
336 /* We know the offset of the object the symbol is contained in.
337 It is a negative value which will be added to the
341 CHECK_STATIC_TLS (map
, sym_map
);
342 *reloc_addr
= (sym
->st_value
+ reloc
->r_addend
343 - sym_map
->l_tls_offset
);
349 #ifndef RTLD_BOOTSTRAP
350 # ifndef RESOLVE_CONFLICT_FIND_MAP
351 /* Not needed for dl-conflict.c. */
354 /* This can happen in trace mode if an object could not be
357 if (__builtin_expect (sym
->st_size
> refsym
->st_size
, 0)
358 || (__builtin_expect (sym
->st_size
< refsym
->st_size
, 0)
359 && __builtin_expect (GLRO(dl_verbose
), 0)))
363 strtab
= (const char *) D_PTR (map
,l_info
[DT_STRTAB
]);
365 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
366 RTLD_PROGNAME
, strtab
+ refsym
->st_name
);
368 memcpy (reloc_addr_arg
, (void *) value
,
369 MIN (sym
->st_size
, refsym
->st_size
));
373 *reloc_addr
= value
+ reloc
->r_addend
;
376 *(unsigned int *) reloc_addr
= value
+ reloc
->r_addend
;
379 *(unsigned short *) reloc_addr
= value
+ reloc
->r_addend
;
382 *(char *) reloc_addr
= value
+ reloc
->r_addend
;
384 # ifndef RESOLVE_CONFLICT_FIND_MAP
386 *reloc_addr
= value
+reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
389 *(unsigned int *) reloc_addr
= (unsigned int)
390 ((int) (value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
) >> 1);
393 *(unsigned int *) reloc_addr
=
394 value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
397 *(unsigned short *) reloc_addr
= (unsigned short)
398 ((short) (value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
) >> 1);
401 *(unsigned short *) reloc_addr
=
402 value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
408 #if !defined(RTLD_BOOTSTRAP) || defined(_NDEBUG)
410 /* We add these checks in the version to relocate ld.so only
411 if we are still debugging. */
412 _dl_reloc_bad_type (map
, r_type
, 0);
420 __attribute__ ((always_inline
))
421 elf_machine_rela_relative (Elf64_Addr l_addr
, const Elf64_Rela
*reloc
,
422 void *const reloc_addr_arg
)
424 Elf64_Addr
*const reloc_addr
= reloc_addr_arg
;
425 *reloc_addr
= l_addr
+ reloc
->r_addend
;
429 __attribute__ ((always_inline
))
430 elf_machine_lazy_rel (struct link_map
*map
,
431 Elf64_Addr l_addr
, const Elf64_Rela
*reloc
,
434 Elf64_Addr
*const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
435 const unsigned int r_type
= ELF64_R_TYPE (reloc
->r_info
);
436 /* Check for unexpected PLT reloc type. */
437 if (__glibc_likely (r_type
== R_390_JMP_SLOT
))
439 if (__builtin_expect (map
->l_mach
.plt
, 0) == 0)
440 *reloc_addr
+= l_addr
;
444 + (((Elf64_Addr
) reloc_addr
) - map
->l_mach
.gotplt
) * 4;
446 else if (__glibc_likely (r_type
== R_390_IRELATIVE
))
448 Elf64_Addr value
= map
->l_addr
+ reloc
->r_addend
;
449 if (__glibc_likely (!skip_ifunc
))
450 value
= elf_ifunc_invoke (value
);
454 _dl_reloc_bad_type (map
, r_type
, 1);
457 #endif /* RESOLVE_MAP */