1 /* Copyright (C) 1995-2017 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 License as
7 published by the Free Software Foundation; either version 2.1 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 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, see
17 <http://www.gnu.org/licenses/>. */
22 #define ELF_MACHINE_NAME "aarch64"
26 #include <dl-tlsdesc.h>
28 #include <cpu-features.c>
30 /* Return nonzero iff ELF header is compatible with the running host. */
31 static inline int __attribute__ ((unused
))
32 elf_machine_matches_host (const ElfW(Ehdr
) *ehdr
)
34 return ehdr
->e_machine
== EM_AARCH64
;
37 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
38 first element of the GOT. */
39 static inline ElfW(Addr
) __attribute__ ((unused
))
40 elf_machine_dynamic (void)
42 extern const ElfW(Addr
) _GLOBAL_OFFSET_TABLE_
[] attribute_hidden
;
43 return _GLOBAL_OFFSET_TABLE_
[0];
46 /* Return the run-time load address of the shared object. */
48 static inline ElfW(Addr
) __attribute__ ((unused
))
49 elf_machine_load_address (void)
51 /* To figure out the load address we use the definition that for any symbol:
52 dynamic_addr(symbol) = static_addr(symbol) + load_addr
54 The choice of symbol is arbitrary. The static address we obtain
55 by constructing a non GOT reference to the symbol, the dynamic
56 address of the symbol we compute using adrp/add to compute the
57 symbol's address relative to the PC.
58 This depends on 32/16bit relocations being resolved at link time
59 and that the static address fits in the 32/16 bits. */
61 ElfW(Addr
) static_addr
;
62 ElfW(Addr
) dynamic_addr
;
65 " adrp %1, _dl_start; \n"
67 " add %1, %1, #:lo12:_dl_start \n"
69 " add %w1, %w1, #:lo12:_dl_start \n"
80 " .short _dl_start \n"
81 # ifndef __AARCH64EB__
86 : "=r" (static_addr
), "=r" (dynamic_addr
));
87 return dynamic_addr
- static_addr
;
90 /* Set up the loaded object described by L so its unrelocated PLT
91 entries will jump to the on-demand fixup code in dl-runtime.c. */
93 static inline int __attribute__ ((unused
))
94 elf_machine_runtime_setup (struct link_map
*l
, int lazy
, int profile
)
96 if (l
->l_info
[DT_JMPREL
] && lazy
)
99 extern void _dl_runtime_resolve (ElfW(Word
));
100 extern void _dl_runtime_profile (ElfW(Word
));
102 got
= (ElfW(Addr
) *) D_PTR (l
, l_info
[DT_PLTGOT
]);
105 l
->l_mach
.plt
= got
[1] + l
->l_addr
;
107 got
[1] = (ElfW(Addr
)) l
;
109 /* The got[2] entry contains the address of a function which gets
110 called to get the address of a so far unresolved function and
111 jump to it. The profiling extension of the dynamic linker allows
112 to intercept the calls to collect information. In this case we
113 don't store the address in the GOT so that all future calls also
114 end in this function. */
117 got
[2] = (ElfW(Addr
)) &_dl_runtime_profile
;
119 if (GLRO(dl_profile
) != NULL
120 && _dl_name_match_p (GLRO(dl_profile
), l
))
121 /* Say that we really want profiling and the timers are
123 GL(dl_profile_map
) = l
;
127 /* This function will get called to fix up the GOT entry
128 indicated by the offset on the stack, and then jump to
129 the resolved address. */
130 got
[2] = (ElfW(Addr
)) &_dl_runtime_resolve
;
134 if (l
->l_info
[ADDRIDX (DT_TLSDESC_GOT
)] && lazy
)
135 *(ElfW(Addr
)*)(D_PTR (l
, l_info
[ADDRIDX (DT_TLSDESC_GOT
)]) + l
->l_addr
)
136 = (ElfW(Addr
)) &_dl_tlsdesc_resolve_rela
;
141 /* Initial entry point for the dynamic linker. The C function
142 _dl_start is the real entry point, its return value is the user
143 program's entry point */
145 # define RTLD_START RTLD_START_1 ("x", "3", "sp")
147 # define RTLD_START RTLD_START_1 ("w", "2", "wsp")
151 #define RTLD_START_1(PTR, PTR_SIZE_LOG, PTR_SP) asm ("\
154 .type _start, %function \n\
155 .globl _dl_start_user \n\
156 .type _dl_start_user, %function \n\
158 mov " PTR "0, " PTR_SP " \n\
160 // returns user entry point in x0 \n\
163 // get the original arg count \n\
164 ldr " PTR "1, [sp] \n\
165 // get the argv address \n\
166 add " PTR "2, " PTR_SP ", #(1<<" PTR_SIZE_LOG ") \n\
167 // get _dl_skip_args to see if we were \n\
168 // invoked as an executable \n\
169 adrp x4, _dl_skip_args \n\
170 ldr w4, [x4, #:lo12:_dl_skip_args] \n\
171 // do we need to adjust argc/argv \n\
173 beq .L_done_stack_adjust \n\
174 // subtract _dl_skip_args from original arg count \n\
175 sub " PTR "1, " PTR "1, " PTR "4 \n\
176 // store adjusted argc back to stack \n\
177 str " PTR "1, [sp] \n\
178 // find the first unskipped argument \n\
179 mov " PTR "3, " PTR "2 \n\
180 add " PTR "4, " PTR "2, " PTR "4, lsl #" PTR_SIZE_LOG " \n\
181 // shuffle argv down \n\
182 1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\
183 str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\
186 // shuffle envp down \n\
187 1: ldr " PTR "5, [x4], #(1<<" PTR_SIZE_LOG ") \n\
188 str " PTR "5, [x3], #(1<<" PTR_SIZE_LOG ") \n\
191 // shuffle auxv down \n\
192 1: ldp " PTR "0, " PTR "5, [x4, #(2<<" PTR_SIZE_LOG ")]! \n\
193 stp " PTR "0, " PTR "5, [x3], #(2<<" PTR_SIZE_LOG ") \n\
196 // Update _dl_argv \n\
197 adrp x3, __GI__dl_argv \n\
198 str " PTR "2, [x3, #:lo12:__GI__dl_argv] \n\
199 .L_done_stack_adjust: \n\
201 add " PTR "3, " PTR "2, " PTR "1, lsl #" PTR_SIZE_LOG " \n\
202 add " PTR "3, " PTR "3, #(1<<" PTR_SIZE_LOG ") \n\
203 adrp x16, _rtld_local \n\
204 add " PTR "16, " PTR "16, #:lo12:_rtld_local \n\
205 ldr " PTR "0, [x16] \n\
207 // load the finalizer function \n\
208 adrp x0, _dl_fini \n\
209 add " PTR "0, " PTR "0, #:lo12:_dl_fini \n\
210 // jump to the user_s entry point \n\
214 #define elf_machine_type_class(type) \
215 ((((type) == AARCH64_R(JUMP_SLOT) \
216 || (type) == AARCH64_R(TLS_DTPMOD) \
217 || (type) == AARCH64_R(TLS_DTPREL) \
218 || (type) == AARCH64_R(TLS_TPREL) \
219 || (type) == AARCH64_R(TLSDESC)) * ELF_RTYPE_CLASS_PLT) \
220 | (((type) == AARCH64_R(COPY)) * ELF_RTYPE_CLASS_COPY) \
221 | (((type) == AARCH64_R(GLOB_DAT)) * ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA))
223 #define ELF_MACHINE_JMP_SLOT AARCH64_R(JUMP_SLOT)
225 /* AArch64 uses RELA not REL */
226 #define ELF_MACHINE_NO_REL 1
227 #define ELF_MACHINE_NO_RELA 0
229 #define DL_PLATFORM_INIT dl_platform_init ()
231 static inline void __attribute__ ((unused
))
232 dl_platform_init (void)
234 if (GLRO(dl_platform
) != NULL
&& *GLRO(dl_platform
) == '\0')
235 /* Avoid an empty string which would disturb us. */
236 GLRO(dl_platform
) = NULL
;
239 /* init_cpu_features has been called early from __libc_start_main in
240 static executable. */
241 init_cpu_features (&GLRO(dl_aarch64_cpu_features
));
246 static inline ElfW(Addr
)
247 elf_machine_fixup_plt (struct link_map
*map
, lookup_t t
,
248 const ElfW(Sym
) *refsym
, const ElfW(Sym
) *sym
,
249 const ElfW(Rela
) *reloc
,
250 ElfW(Addr
) *reloc_addr
,
253 return *reloc_addr
= value
;
256 /* Return the final value of a plt relocation. */
257 static inline ElfW(Addr
)
258 elf_machine_plt_value (struct link_map
*map
,
259 const ElfW(Rela
) *reloc
,
267 /* Names of the architecture-specific auditing callback functions. */
268 #define ARCH_LA_PLTENTER aarch64_gnu_pltenter
269 #define ARCH_LA_PLTEXIT aarch64_gnu_pltexit
274 __attribute__ ((always_inline
))
275 elf_machine_rela (struct link_map
*map
, const ElfW(Rela
) *reloc
,
276 const ElfW(Sym
) *sym
, const struct r_found_version
*version
,
277 void *const reloc_addr_arg
, int skip_ifunc
)
279 ElfW(Addr
) *const reloc_addr
= reloc_addr_arg
;
280 const unsigned int r_type
= ELFW (R_TYPE
) (reloc
->r_info
);
282 if (__builtin_expect (r_type
== AARCH64_R(RELATIVE
), 0))
283 *reloc_addr
= map
->l_addr
+ reloc
->r_addend
;
284 else if (__builtin_expect (r_type
== R_AARCH64_NONE
, 0))
288 const ElfW(Sym
) *const refsym
= sym
;
289 struct link_map
*sym_map
= RESOLVE_MAP (&sym
, version
, r_type
);
290 ElfW(Addr
) value
= sym_map
== NULL
? 0 : sym_map
->l_addr
+ sym
->st_value
;
293 && __glibc_unlikely (ELFW(ST_TYPE
) (sym
->st_info
) == STT_GNU_IFUNC
)
294 && __glibc_likely (sym
->st_shndx
!= SHN_UNDEF
)
295 && __glibc_likely (!skip_ifunc
))
296 value
= elf_ifunc_invoke (value
);
300 case AARCH64_R(COPY
):
304 if (sym
->st_size
> refsym
->st_size
305 || (GLRO(dl_verbose
) && sym
->st_size
< refsym
->st_size
))
309 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
311 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
312 RTLD_PROGNAME
, strtab
+ refsym
->st_name
);
314 memcpy (reloc_addr_arg
, (void *) value
,
315 MIN (sym
->st_size
, refsym
->st_size
));
318 case AARCH64_R(RELATIVE
):
319 case AARCH64_R(GLOB_DAT
):
320 case AARCH64_R(JUMP_SLOT
):
321 case AARCH64_R(ABS32
):
323 case AARCH64_R(ABS64
):
325 *reloc_addr
= value
+ reloc
->r_addend
;
328 case AARCH64_R(TLSDESC
):
330 struct tlsdesc
volatile *td
=
331 (struct tlsdesc
volatile *)reloc_addr
;
332 #ifndef RTLD_BOOTSTRAP
335 td
->arg
= (void*)reloc
->r_addend
;
336 td
->entry
= _dl_tlsdesc_undefweak
;
341 #ifndef RTLD_BOOTSTRAP
343 CHECK_STATIC_TLS (map
, sym_map
);
345 if (!TRY_STATIC_TLS (map
, sym_map
))
347 td
->arg
= _dl_make_tlsdesc_dynamic
348 (sym_map
, sym
->st_value
+ reloc
->r_addend
);
349 td
->entry
= _dl_tlsdesc_dynamic
;
355 td
->arg
= (void*)(sym
->st_value
+ sym_map
->l_tls_offset
357 td
->entry
= _dl_tlsdesc_return
;
363 case AARCH64_R(TLS_DTPMOD
):
364 #ifdef RTLD_BOOTSTRAP
369 *reloc_addr
= sym_map
->l_tls_modid
;
374 case AARCH64_R(TLS_DTPREL
):
376 *reloc_addr
= sym
->st_value
+ reloc
->r_addend
;
379 case AARCH64_R(TLS_TPREL
):
382 CHECK_STATIC_TLS (map
, sym_map
);
384 sym
->st_value
+ reloc
->r_addend
+ sym_map
->l_tls_offset
;
388 case AARCH64_R(IRELATIVE
):
389 value
= map
->l_addr
+ reloc
->r_addend
;
390 value
= elf_ifunc_invoke (value
);
395 _dl_reloc_bad_type (map
, r_type
, 0);
402 __attribute__ ((always_inline
))
403 elf_machine_rela_relative (ElfW(Addr
) l_addr
,
404 const ElfW(Rela
) *reloc
,
405 void *const reloc_addr_arg
)
407 ElfW(Addr
) *const reloc_addr
= reloc_addr_arg
;
408 *reloc_addr
= l_addr
+ reloc
->r_addend
;
412 __attribute__ ((always_inline
))
413 elf_machine_lazy_rel (struct link_map
*map
,
415 const ElfW(Rela
) *reloc
,
418 ElfW(Addr
) *const reloc_addr
= (void *) (l_addr
+ reloc
->r_offset
);
419 const unsigned int r_type
= ELFW (R_TYPE
) (reloc
->r_info
);
420 /* Check for unexpected PLT reloc type. */
421 if (__builtin_expect (r_type
== AARCH64_R(JUMP_SLOT
), 1))
423 if (__builtin_expect (map
->l_mach
.plt
, 0) == 0)
424 *reloc_addr
+= l_addr
;
426 *reloc_addr
= map
->l_mach
.plt
;
428 else if (__builtin_expect (r_type
== AARCH64_R(TLSDESC
), 1))
430 struct tlsdesc
volatile *td
=
431 (struct tlsdesc
volatile *)reloc_addr
;
433 td
->arg
= (void*)reloc
;
434 td
->entry
= (void*)(D_PTR (map
, l_info
[ADDRIDX (DT_TLSDESC_PLT
)])
437 else if (__glibc_unlikely (r_type
== AARCH64_R(IRELATIVE
)))
439 ElfW(Addr
) value
= map
->l_addr
+ reloc
->r_addend
;
440 if (__glibc_likely (!skip_ifunc
))
441 value
= elf_ifunc_invoke (value
);
445 _dl_reloc_bad_type (map
, r_type
, 1);