1 /* Machine-dependent ELF dynamic relocation inline functions.
3 Copyright (C) 2001-2023 Free Software Foundation, Inc.
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 Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the 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 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
23 #define ELF_MACHINE_NAME "s390x"
25 #include <sys/param.h>
28 #include <sysdeps/s390/dl-procinfo.h>
30 #include <dl-static-tls.h>
31 #include <dl-machine-rel.h>
32 #include <cpu-features.c>
34 #define ELF_MACHINE_IRELATIVE R_390_IRELATIVE
36 /* This is an older, now obsolete value. */
37 #define EM_S390_OLD 0xA390
39 /* Return nonzero iff E_MACHINE is compatible with the running host. */
41 elf_machine_matches_host (const Elf64_Ehdr
*ehdr
)
43 return (ehdr
->e_machine
== EM_S390
|| ehdr
->e_machine
== EM_S390_OLD
)
44 && ehdr
->e_ident
[EI_CLASS
] == ELFCLASS64
;
47 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
48 first element of the GOT. This must be inlined in a function which
51 static inline Elf64_Addr
52 elf_machine_dynamic (void)
54 register Elf64_Addr
*got
;
56 __asm__ ( " larl %0,_GLOBAL_OFFSET_TABLE_\n"
57 : "=&a" (got
) : : "0" );
62 /* Return the run-time load address of the shared object. */
63 static inline Elf64_Addr
64 elf_machine_load_address (void)
68 __asm__( " larl %0,_dl_start\n"
69 " larl 1,_GLOBAL_OFFSET_TABLE_\n"
70 " lghi 2,_dl_start@GOT\n"
72 : "=&d" (addr
) : : "1", "2" );
76 /* Set up the loaded object described by L so its unrelocated PLT
77 entries will jump to the on-demand fixup code in dl-runtime.c. */
79 static inline int __attribute__ ((unused
))
80 elf_machine_runtime_setup (struct link_map
*l
, struct r_scope_elem
*scope
[],
81 int lazy
, int profile
)
83 extern void _dl_runtime_resolve (Elf64_Word
);
84 extern void _dl_runtime_profile (Elf64_Word
);
85 #if defined HAVE_S390_VX_ASM_SUPPORT
86 extern void _dl_runtime_resolve_vx (Elf64_Word
);
87 extern void _dl_runtime_profile_vx (Elf64_Word
);
90 if (l
->l_info
[DT_JMPREL
] && lazy
)
92 /* The GOT entries for functions in the PLT have not yet been filled
93 in. Their initial contents will arrange when called to push an
94 offset into the .rela.plt section, push _GLOBAL_OFFSET_TABLE_[1],
95 and then jump to _GLOBAL_OFFSET_TABLE[2]. */
97 got
= (Elf64_Addr
*) D_PTR (l
, l_info
[DT_PLTGOT
]);
98 /* If a library is prelinked but we have to relocate anyway,
99 we have to be able to undo the prelinking of .got.plt.
100 The prelinker saved us here address of .plt + 0x2e. */
103 l
->l_mach
.plt
= got
[1] + l
->l_addr
;
104 l
->l_mach
.jmprel
= (const Elf64_Rela
*) D_PTR (l
, l_info
[DT_JMPREL
]);
106 got
[1] = (Elf64_Addr
) l
; /* Identify this shared object. */
108 /* The got[2] entry contains the address of a function which gets
109 called to get the address of a so far unresolved function and
110 jump to it. The profiling extension of the dynamic linker allows
111 to intercept the calls to collect information. In this case we
112 don't store the address in the GOT so that all future calls also
113 end in this function. */
114 if (__glibc_unlikely (profile
))
116 #if defined HAVE_S390_VX_ASM_SUPPORT
117 if (GLRO(dl_hwcap
) & HWCAP_S390_VX
)
118 got
[2] = (Elf64_Addr
) &_dl_runtime_profile_vx
;
120 got
[2] = (Elf64_Addr
) &_dl_runtime_profile
;
122 got
[2] = (Elf64_Addr
) &_dl_runtime_profile
;
125 if (GLRO(dl_profile
) != NULL
126 && _dl_name_match_p (GLRO(dl_profile
), l
))
127 /* This is the object we are looking for. Say that we really
128 want profiling and the timers are started. */
129 GL(dl_profile_map
) = l
;
133 /* This function will get called to fix up the GOT entry indicated by
134 the offset on the stack, and then jump to the resolved address. */
135 #if defined HAVE_S390_VX_ASM_SUPPORT
136 if (GLRO(dl_hwcap
) & HWCAP_S390_VX
)
137 got
[2] = (Elf64_Addr
) &_dl_runtime_resolve_vx
;
139 got
[2] = (Elf64_Addr
) &_dl_runtime_resolve
;
141 got
[2] = (Elf64_Addr
) &_dl_runtime_resolve
;
149 /* Initial entry point code for the dynamic linker.
150 The C function `_dl_start' is the real entry point;
151 its return value is the user program's entry point. */
153 #define RTLD_START __asm__ ("\n\
157 .globl _dl_start_user\n\
160 # Alloc stack frame\n\
162 # Set the back chain to zero\n\
163 xc 0(8,%r15),0(%r15)\n\
164 # Call _dl_start with %r2 pointing to arg on stack\n\
165 brasl %r14,_dl_start # call _dl_start\n\
167 # Save the user entry point address in %r8.\n\
169 # Point %r12 at the GOT.\n\
170 larl %r12,_GLOBAL_OFFSET_TABLE_\n\
171 # The special initializer gets called with the stack just\n\
172 # as the application's entry point will see it; it can\n\
173 # switch stacks if it moves these contents over.\n\
174 " RTLD_START_SPECIAL_INIT "\n\
175 # Call the function to run the initializers.\n\
176 # Load the parameters:\n\
177 # (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
178 lghi %r2,_rtld_local@GOT\n\
179 lg %r2,0(%r2,%r12)\n\
185 la %r5,176(%r5,%r15)\n\
186 brasl %r14,_dl_init@PLT\n\
187 # Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
188 lghi %r14,_dl_fini@GOT\n\
189 lg %r14,0(%r14,%r12)\n\
190 # Free stack frame\n\
192 # Jump to the user's entry point (saved in %r8).\n\
196 #ifndef RTLD_START_SPECIAL_INIT
197 #define RTLD_START_SPECIAL_INIT /* nothing */
200 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
201 TLS variable, so undefined references should not be allowed to
203 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
204 of the main executable's symbols, as for a COPY reloc. */
205 #define elf_machine_type_class(type) \
206 ((((type) == R_390_JMP_SLOT || (type) == R_390_TLS_DTPMOD \
207 || (type) == R_390_TLS_DTPOFF || (type) == R_390_TLS_TPOFF) \
208 * ELF_RTYPE_CLASS_PLT) \
209 | (((type) == R_390_COPY) * ELF_RTYPE_CLASS_COPY))
211 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
212 #define ELF_MACHINE_JMP_SLOT R_390_JMP_SLOT
214 /* We define an initialization functions. This is called very early in
216 #define DL_PLATFORM_INIT dl_platform_init ()
218 static inline void __attribute__ ((unused
))
219 dl_platform_init (void)
221 if (GLRO(dl_platform
) != NULL
&& *GLRO(dl_platform
) == '\0')
222 /* Avoid an empty string which would disturb us. */
223 GLRO(dl_platform
) = NULL
;
226 /* init_cpu_features has been called early from __libc_start_main in
227 static executable. */
228 init_cpu_features (&GLRO(dl_s390_cpu_features
));
233 static inline Elf64_Addr
234 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
235 const ElfW(Sym
) *refsym
, const ElfW(Sym
) *sym
,
236 const Elf64_Rela
*reloc
,
237 Elf64_Addr
*reloc_addr
, Elf64_Addr value
)
239 return *reloc_addr
= value
;
242 /* Return the final value of a plt relocation. */
243 static inline Elf64_Addr
244 elf_machine_plt_value (struct link_map
*map
, const Elf64_Rela
*reloc
,
250 /* Names of the architecture-specific auditing callback functions. */
251 #define ARCH_LA_PLTENTER s390_64_gnu_pltenter
252 #define ARCH_LA_PLTEXIT s390_64_gnu_pltexit
254 #endif /* !dl_machine_h */
258 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
259 MAP is the object containing the reloc. */
262 __attribute__ ((always_inline
))
263 elf_machine_rela (struct link_map
*map
, struct r_scope_elem
*scope
[],
264 const Elf64_Rela
*reloc
, const Elf64_Sym
*sym
,
265 const struct r_found_version
*version
,
266 void *const reloc_addr_arg
, int skip_ifunc
)
268 Elf64_Addr
*const reloc_addr
= reloc_addr_arg
;
269 const unsigned int r_type
= ELF64_R_TYPE (reloc
->r_info
);
271 #if !defined RTLD_BOOTSTRAP
272 if (__glibc_unlikely (r_type
== R_390_RELATIVE
))
273 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
276 if (__glibc_unlikely (r_type
== R_390_NONE
))
280 #if !defined RTLD_BOOTSTRAP
281 /* Only needed for R_390_COPY below. */
282 const Elf64_Sym
*const refsym
= sym
;
284 struct link_map
*sym_map
= RESOLVE_MAP (map
, scope
, &sym
, version
,
286 Elf64_Addr value
= SYMBOL_ADDRESS (sym_map
, sym
, true);
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 case R_390_TLS_DTPMOD
:
309 #ifdef RTLD_BOOTSTRAP
310 /* During startup the dynamic linker is always the module
312 XXX If this relocation is necessary move before RESOLVE
316 /* Get the information from the link map returned by the
319 *reloc_addr
= sym_map
->l_tls_modid
;
322 case R_390_TLS_DTPOFF
:
323 #ifndef RTLD_BOOTSTRAP
324 /* During relocation all TLS symbols are defined and used.
325 Therefore the offset is already correct. */
327 *reloc_addr
= sym
->st_value
+ reloc
->r_addend
;
330 case R_390_TLS_TPOFF
:
331 /* The offset is negative, forward from the thread pointer. */
332 #ifdef RTLD_BOOTSTRAP
333 *reloc_addr
= sym
->st_value
+ reloc
->r_addend
- map
->l_tls_offset
;
335 /* We know the offset of the object the symbol is contained in.
336 It is a negative value which will be added to the
340 CHECK_STATIC_TLS (map
, sym_map
);
341 *reloc_addr
= (sym
->st_value
+ reloc
->r_addend
342 - sym_map
->l_tls_offset
);
347 #ifndef RTLD_BOOTSTRAP
348 /* Not needed for dl-conflict.c. */
351 /* This can happen in trace mode if an object could not be
354 if (__builtin_expect (sym
->st_size
> refsym
->st_size
, 0)
355 || (__builtin_expect (sym
->st_size
< refsym
->st_size
, 0)
356 && __builtin_expect (GLRO(dl_verbose
), 0)))
360 strtab
= (const char *) D_PTR (map
,l_info
[DT_STRTAB
]);
362 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
363 RTLD_PROGNAME
, strtab
+ refsym
->st_name
);
365 memcpy (reloc_addr_arg
, (void *) value
,
366 MIN (sym
->st_size
, refsym
->st_size
));
369 *reloc_addr
= value
+ reloc
->r_addend
;
372 *(unsigned int *) reloc_addr
= value
+ reloc
->r_addend
;
375 *(unsigned short *) reloc_addr
= value
+ reloc
->r_addend
;
378 *(char *) reloc_addr
= value
+ reloc
->r_addend
;
381 *reloc_addr
= value
+reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
384 *(unsigned int *) reloc_addr
= (unsigned int)
385 ((int) (value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
) >> 1);
388 *(unsigned int *) reloc_addr
=
389 value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
392 *(unsigned short *) reloc_addr
= (unsigned short)
393 ((short) (value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
) >> 1);
396 *(unsigned short *) reloc_addr
=
397 value
+ reloc
->r_addend
- (Elf64_Addr
) reloc_addr
;
402 #if !defined(RTLD_BOOTSTRAP) || defined(_NDEBUG)
404 /* We add these checks in the version to relocate ld.so only
405 if we are still debugging. */
406 _dl_reloc_bad_type (map
, r_type
, 0);
414 __attribute__ ((always_inline
))
415 elf_machine_rela_relative (Elf64_Addr l_addr
, const Elf64_Rela
*reloc
,
416 void *const reloc_addr_arg
)
418 Elf64_Addr
*const reloc_addr
= reloc_addr_arg
;
419 *reloc_addr
= l_addr
+ reloc
->r_addend
;
423 __attribute__ ((always_inline
))
424 elf_machine_lazy_rel (struct link_map
*map
, struct r_scope_elem
*scope
[],
425 Elf64_Addr l_addr
, const Elf64_Rela
*reloc
,
428 Elf64_Addr
*const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
429 const unsigned int r_type
= ELF64_R_TYPE (reloc
->r_info
);
430 /* Check for unexpected PLT reloc type. */
431 if (__glibc_likely (r_type
== R_390_JMP_SLOT
))
433 if (__builtin_expect (map
->l_mach
.plt
, 0) == 0)
434 *reloc_addr
+= l_addr
;
436 *reloc_addr
= map
->l_mach
.plt
+ (reloc
- map
->l_mach
.jmprel
) * 32;
438 else if (__glibc_likely (r_type
== R_390_IRELATIVE
))
440 Elf64_Addr value
= map
->l_addr
+ reloc
->r_addend
;
441 if (__glibc_likely (!skip_ifunc
))
442 value
= elf_ifunc_invoke (value
);
446 _dl_reloc_bad_type (map
, r_type
, 1);
449 #endif /* RESOLVE_MAP */