1 /* Copyright (C) 1995-2014 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"
25 #include <dl-tlsdesc.h>
28 /* Return nonzero iff ELF header is compatible with the running host. */
29 static inline int __attribute__ ((unused))
30 elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
32 return ehdr->e_machine == EM_AARCH64;
35 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
36 first element of the GOT. */
37 static inline ElfW(Addr) __attribute__ ((unused))
38 elf_machine_dynamic (void)
40 extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden;
41 return _GLOBAL_OFFSET_TABLE_[0];
44 /* Return the run-time load address of the shared object. */
46 static inline ElfW(Addr) __attribute__ ((unused))
47 elf_machine_load_address (void)
49 /* To figure out the load address we use the definition that for any symbol:
50 dynamic_addr(symbol) = static_addr(symbol) + load_addr
52 The choice of symbol is arbitrary. The static address we obtain
53 by constructing a non GOT reference to the symbol, the dynamic
54 address of the symbol we compute using adrp/add to compute the
55 symbol's address relative to the PC. */
57 ElfW(Addr) static_addr;
58 ElfW(Addr) dynamic_addr;
61 adrp %1, _dl_start; \n\
62 add %1, %1, #:lo12:_dl_start \n\
65 1: .word _dl_start \n\
67 " : "=r" (static_addr), "=r" (dynamic_addr));
68 return dynamic_addr - static_addr;
71 /* Set up the loaded object described by L so its unrelocated PLT
72 entries will jump to the on-demand fixup code in dl-runtime.c. */
74 static inline int __attribute__ ((unused))
75 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
77 if (l->l_info[DT_JMPREL] && lazy)
80 extern void _dl_runtime_resolve (ElfW(Word));
81 extern void _dl_runtime_profile (ElfW(Word));
83 got = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
86 l->l_mach.plt = got[1] + l->l_addr;
88 got[1] = (ElfW(Addr)) l;
90 /* The got[2] entry contains the address of a function which gets
91 called to get the address of a so far unresolved function and
92 jump to it. The profiling extension of the dynamic linker allows
93 to intercept the calls to collect information. In this case we
94 don't store the address in the GOT so that all future calls also
95 end in this function. */
98 got[2] = (ElfW(Addr)) &_dl_runtime_profile;
100 if (GLRO(dl_profile) != NULL
101 && _dl_name_match_p (GLRO(dl_profile), l))
102 /* Say that we really want profiling and the timers are
104 GL(dl_profile_map) = l;
108 /* This function will get called to fix up the GOT entry
109 indicated by the offset on the stack, and then jump to
110 the resolved address. */
111 got[2] = (ElfW(Addr)) &_dl_runtime_resolve;
115 if (l->l_info[ADDRIDX (DT_TLSDESC_GOT)] && lazy)
116 *(Elf64_Addr*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_GOT)]) + l->l_addr)
117 = (Elf64_Addr) &_dl_tlsdesc_resolve_rela;
122 /* Initial entry point for the dynamic linker. The C function
123 _dl_start is the real entry point, its return value is the user
124 program's entry point */
126 #define RTLD_START asm ("\
129 .type _start, %function \n\
130 .globl _dl_start_user \n\
131 .type _dl_start_user, %function \n\
135 // returns user entry point in x0 \n\
138 // get the original arg count \n\
140 // get the argv address \n\
142 // get _dl_skip_args to see if we were \n\
143 // invoked as an executable \n\
144 adrp x4, _dl_skip_args \n\
145 ldr w4, [x4, #:lo12:_dl_skip_args] \n\
146 // do we need to adjust argc/argv \n\
148 beq .L_done_stack_adjust \n\
149 // subtract _dl_skip_args from original arg count \n\
151 // store adjusted argc back to stack \n\
153 // find the first unskipped argument \n\
155 add x4, x2, x4, lsl #3 \n\
156 // shuffle argv down \n\
157 1: ldr x5, [x4], #8 \n\
161 // shuffle envp down \n\
162 1: ldr x5, [x4], #8 \n\
166 // shuffle auxv down \n\
167 1: ldp x0, x5, [x4, #16]! \n\
168 stp x0, x5, [x3], #16 \n\
171 // Update _dl_argv \n\
172 adrp x3, _dl_argv \n\
173 str x2, [x3, #:lo12:_dl_argv] \n\
174 .L_done_stack_adjust: \n\
176 add x3, x2, x1, lsl #3 \n\
178 adrp x16, _rtld_local \n\
179 add x16, x16, #:lo12:_rtld_local \n\
181 bl _dl_init_internal \n\
182 // load the finalizer function \n\
183 adrp x0, _dl_fini \n\
184 add x0, x0, #:lo12:_dl_fini \n\
185 // jump to the user_s entry point \n\
189 #define elf_machine_type_class(type) \
190 ((((type) == R_AARCH64_JUMP_SLOT || \
191 (type) == R_AARCH64_TLS_DTPMOD64 || \
192 (type) == R_AARCH64_TLS_DTPREL64 || \
193 (type) == R_AARCH64_TLS_TPREL64 || \
194 (type) == R_AARCH64_TLSDESC) * ELF_RTYPE_CLASS_PLT) \
195 | (((type) == R_AARCH64_COPY) * ELF_RTYPE_CLASS_COPY))
197 #define ELF_MACHINE_JMP_SLOT R_AARCH64_JUMP_SLOT
199 /* AArch64 uses RELA not REL */
200 #define ELF_MACHINE_NO_REL 1
202 static inline ElfW(Addr)
203 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
204 const ElfW(Rela) *reloc,
205 ElfW(Addr) *reloc_addr,
208 return *reloc_addr = value;
211 /* Return the final value of a plt relocation. */
212 static inline ElfW(Addr)
213 elf_machine_plt_value (struct link_map *map,
214 const ElfW(Rela) *reloc,
222 /* Names of the architecture-specific auditing callback functions. */
223 #define ARCH_LA_PLTENTER aarch64_gnu_pltenter
224 #define ARCH_LA_PLTEXIT aarch64_gnu_pltexit
229 __attribute__ ((always_inline))
230 elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
231 const ElfW(Sym) *sym, const struct r_found_version *version,
232 void *const reloc_addr_arg, int skip_ifunc)
234 ElfW(Addr) *const reloc_addr = reloc_addr_arg;
235 const unsigned int r_type = ELF64_R_TYPE (reloc->r_info);
237 if (__builtin_expect (r_type == R_AARCH64_RELATIVE, 0))
238 *reloc_addr = map->l_addr + reloc->r_addend;
239 else if (__builtin_expect (r_type == R_AARCH64_NONE, 0))
243 const ElfW(Sym) *const refsym = sym;
244 struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
245 ElfW(Addr) value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value;
248 && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
249 && __glibc_likely (sym->st_shndx != SHN_UNDEF)
250 && __glibc_likely (!skip_ifunc))
251 value = elf_ifunc_invoke (value);
259 if (sym->st_size > refsym->st_size
260 || (GLRO(dl_verbose) && sym->st_size < refsym->st_size))
264 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
266 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
267 RTLD_PROGNAME, strtab + refsym->st_name);
269 memcpy (reloc_addr_arg, (void *) value,
270 MIN (sym->st_size, refsym->st_size));
273 case R_AARCH64_RELATIVE:
274 case R_AARCH64_GLOB_DAT:
275 case R_AARCH64_JUMP_SLOT:
276 case R_AARCH64_ABS32:
277 case R_AARCH64_ABS64:
278 *reloc_addr = value + reloc->r_addend;
281 case R_AARCH64_TLSDESC:
283 struct tlsdesc volatile *td =
284 (struct tlsdesc volatile *)reloc_addr;
285 #ifndef RTLD_BOOTSTRAP
288 td->arg = (void*)reloc->r_addend;
289 td->entry = _dl_tlsdesc_undefweak;
294 #ifndef RTLD_BOOTSTRAP
296 CHECK_STATIC_TLS (map, sym_map);
298 if (!TRY_STATIC_TLS (map, sym_map))
300 td->arg = _dl_make_tlsdesc_dynamic
301 (sym_map, sym->st_value + reloc->r_addend);
302 td->entry = _dl_tlsdesc_dynamic;
308 td->arg = (void*)(sym->st_value + sym_map->l_tls_offset
310 td->entry = _dl_tlsdesc_return;
316 case R_AARCH64_TLS_DTPMOD64:
317 #ifdef RTLD_BOOTSTRAP
322 *reloc_addr = sym_map->l_tls_modid;
327 case R_AARCH64_TLS_DTPREL64:
329 *reloc_addr = sym->st_value + reloc->r_addend;
332 case R_AARCH64_TLS_TPREL64:
335 CHECK_STATIC_TLS (map, sym_map);
337 sym->st_value + reloc->r_addend + sym_map->l_tls_offset;
341 case R_AARCH64_IRELATIVE:
342 value = map->l_addr + reloc->r_addend;
343 value = elf_ifunc_invoke (value);
348 _dl_reloc_bad_type (map, r_type, 0);
355 __attribute__ ((always_inline))
356 elf_machine_rela_relative (ElfW(Addr) l_addr,
357 const ElfW(Rela) *reloc,
358 void *const reloc_addr_arg)
360 ElfW(Addr) *const reloc_addr = reloc_addr_arg;
361 *reloc_addr = l_addr + reloc->r_addend;
365 __attribute__ ((always_inline))
366 elf_machine_lazy_rel (struct link_map *map,
368 const ElfW(Rela) *reloc,
371 ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
372 const unsigned int r_type = ELF64_R_TYPE (reloc->r_info);
373 /* Check for unexpected PLT reloc type. */
374 if (__builtin_expect (r_type == R_AARCH64_JUMP_SLOT, 1))
376 if (__builtin_expect (map->l_mach.plt, 0) == 0)
377 *reloc_addr += l_addr;
379 *reloc_addr = map->l_mach.plt;
381 else if (__builtin_expect (r_type == R_AARCH64_TLSDESC, 1))
383 struct tlsdesc volatile *td =
384 (struct tlsdesc volatile *)reloc_addr;
386 td->arg = (void*)reloc;
387 td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)])
390 else if (__glibc_unlikely (r_type == R_AARCH64_IRELATIVE))
392 ElfW(Addr) value = map->l_addr + reloc->r_addend;
393 if (__glibc_likely (!skip_ifunc))
394 value = elf_ifunc_invoke (value);
398 _dl_reloc_bad_type (map, r_type, 1);