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4cca6b86 | 1 | /* Machine-dependent ELF dynamic relocation inline functions. PowerPC version. |
32c075e1 | 2 | Copyright (C) 1995-2002, 2003, 2005 Free Software Foundation, Inc. |
4cca6b86 UD |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
4cca6b86 UD |
9 | |
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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
4cca6b86 | 14 | |
41bdb6e2 AJ |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, write to the Free | |
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
18 | 02111-1307 USA. */ | |
4cca6b86 | 19 | |
1f205a47 UD |
20 | #ifndef dl_machine_h |
21 | #define dl_machine_h | |
22 | ||
4cca6b86 UD |
23 | #define ELF_MACHINE_NAME "powerpc" |
24 | ||
25 | #include <assert.h> | |
bb0ddc2f | 26 | #include <dl-tls.h> |
4cca6b86 | 27 | |
99c7f870 UD |
28 | /* Translate a processor specific dynamic tag to the index |
29 | in l_info array. */ | |
30 | #define DT_PPC(x) (DT_PPC_##x - DT_LOPROC + DT_NUM) | |
31 | ||
ceb579a3 | 32 | /* Return nonzero iff ELF header is compatible with the running host. */ |
c2a32973 | 33 | static inline int |
ceb579a3 | 34 | elf_machine_matches_host (const Elf32_Ehdr *ehdr) |
4cca6b86 | 35 | { |
ceb579a3 | 36 | return ehdr->e_machine == EM_PPC; |
4cca6b86 UD |
37 | } |
38 | ||
99c7f870 UD |
39 | /* Return the value of the GOT pointer. */ |
40 | static inline Elf32_Addr * __attribute__ ((const)) | |
41 | ppc_got (void) | |
42 | { | |
43 | Elf32_Addr *got; | |
44 | #ifdef HAVE_ASM_PPC_REL16 | |
45 | asm ("bcl 20,31,1f\n" | |
46 | "1: mflr %0\n" | |
47 | " addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n" | |
48 | " addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n" | |
49 | : "=b" (got) : : "lr"); | |
50 | #else | |
51 | asm (" bl _GLOBAL_OFFSET_TABLE_-4@local" | |
52 | : "=l" (got)); | |
53 | #endif | |
54 | return got; | |
55 | } | |
4cca6b86 | 56 | |
e61abf83 UD |
57 | /* Return the link-time address of _DYNAMIC, stored as |
58 | the first value in the GOT. */ | |
99c7f870 | 59 | static inline Elf32_Addr __attribute__ ((const)) |
4cca6b86 UD |
60 | elf_machine_dynamic (void) |
61 | { | |
99c7f870 | 62 | return *ppc_got (); |
4cca6b86 UD |
63 | } |
64 | ||
65 | /* Return the run-time load address of the shared object. */ | |
99c7f870 | 66 | static inline Elf32_Addr __attribute__ ((const)) |
4cca6b86 UD |
67 | elf_machine_load_address (void) |
68 | { | |
99c7f870 UD |
69 | Elf32_Addr *branchaddr; |
70 | Elf32_Addr runtime_dynamic; | |
4cca6b86 UD |
71 | |
72 | /* This is much harder than you'd expect. Possibly I'm missing something. | |
73 | The 'obvious' way: | |
74 | ||
75 | Apparently, "bcl 20,31,$+4" is what should be used to load LR | |
76 | with the address of the next instruction. | |
77 | I think this is so that machines that do bl/blr pairing don't | |
78 | get confused. | |
79 | ||
80 | asm ("bcl 20,31,0f ;" | |
e61abf83 UD |
81 | "0: mflr 0 ;" |
82 | "lis %0,0b@ha;" | |
83 | "addi %0,%0,0b@l;" | |
84 | "subf %0,%0,0" | |
85 | : "=b" (addr) : : "r0", "lr"); | |
4cca6b86 UD |
86 | |
87 | doesn't work, because the linker doesn't have to (and in fact doesn't) | |
88 | update the @ha and @l references; the loader (which runs after this | |
89 | code) will do that. | |
90 | ||
91 | Instead, we use the following trick: | |
92 | ||
93 | The linker puts the _link-time_ address of _DYNAMIC at the first | |
94 | word in the GOT. We could branch to that address, if we wanted, | |
95 | by using an @local reloc; the linker works this out, so it's safe | |
96 | to use now. We can't, of course, actually branch there, because | |
97 | we'd cause an illegal instruction exception; so we need to compute | |
98 | the address ourselves. That gives us the following code: */ | |
99 | ||
100 | /* Get address of the 'b _DYNAMIC@local'... */ | |
99c7f870 | 101 | asm ("bcl 20,31,0f;" |
4cca6b86 UD |
102 | "b _DYNAMIC@local;" |
103 | "0:" | |
99c7f870 | 104 | : "=l" (branchaddr)); |
4cca6b86 UD |
105 | |
106 | /* So now work out the difference between where the branch actually points, | |
107 | and the offset of that location in memory from the start of the file. */ | |
99c7f870 UD |
108 | runtime_dynamic = ((Elf32_Addr) branchaddr |
109 | + ((Elf32_Sword) (*branchaddr << 6 & 0xffffff00) >> 6)); | |
110 | ||
111 | return runtime_dynamic - elf_machine_dynamic (); | |
4cca6b86 UD |
112 | } |
113 | ||
114 | #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */ | |
115 | ||
1f205a47 UD |
116 | /* The PLT uses Elf32_Rela relocs. */ |
117 | #define elf_machine_relplt elf_machine_rela | |
4cca6b86 | 118 | |
9ce8b3c8 RM |
119 | /* Mask identifying addresses reserved for the user program, |
120 | where the dynamic linker should not map anything. */ | |
121 | #define ELF_MACHINE_USER_ADDRESS_MASK 0xf0000000UL | |
122 | ||
052b6a6c UD |
123 | /* The actual _start code is in dl-start.S. Use a really |
124 | ugly bit of assembler to let dl-start.o see _dl_start. */ | |
125 | #define RTLD_START asm (".globl _dl_start"); | |
4cca6b86 | 126 | |
052b6a6c UD |
127 | /* Decide where a relocatable object should be loaded. */ |
128 | extern ElfW(Addr) | |
129 | __elf_preferred_address(struct link_map *loader, size_t maplength, | |
130 | ElfW(Addr) mapstartpref); | |
131 | #define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) \ | |
132 | __elf_preferred_address (loader, maplength, mapstartpref) | |
e61abf83 | 133 | |
cf5a372e UD |
134 | /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so |
135 | PLT entries should not be allowed to define the value. | |
136 | ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one | |
137 | of the main executable's symbols, as for a COPY reloc. */ | |
1f205a47 UD |
138 | /* We never want to use a PLT entry as the destination of a |
139 | reloc, when what is being relocated is a branch. This is | |
140 | partly for efficiency, but mostly so we avoid loops. */ | |
32c075e1 | 141 | #if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD) |
bb0ddc2f RM |
142 | #define elf_machine_type_class(type) \ |
143 | ((((type) == R_PPC_JMP_SLOT \ | |
144 | || (type) == R_PPC_REL24 \ | |
7551556f RM |
145 | || ((type) >= R_PPC_DTPMOD32 /* contiguous TLS */ \ |
146 | && (type) <= R_PPC_DTPREL32) \ | |
bb0ddc2f RM |
147 | || (type) == R_PPC_ADDR24) * ELF_RTYPE_CLASS_PLT) \ |
148 | | (((type) == R_PPC_COPY) * ELF_RTYPE_CLASS_COPY)) | |
149 | #else | |
cf5a372e UD |
150 | #define elf_machine_type_class(type) \ |
151 | ((((type) == R_PPC_JMP_SLOT \ | |
152 | || (type) == R_PPC_REL24 \ | |
153 | || (type) == R_PPC_ADDR24) * ELF_RTYPE_CLASS_PLT) \ | |
154 | | (((type) == R_PPC_COPY) * ELF_RTYPE_CLASS_COPY)) | |
bb0ddc2f | 155 | #endif |
4cca6b86 | 156 | |
1f205a47 | 157 | /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */ |
a2b08ee5 | 158 | #define ELF_MACHINE_JMP_SLOT R_PPC_JMP_SLOT |
4cca6b86 | 159 | |
4839f592 AJ |
160 | /* The PowerPC never uses REL relocations. */ |
161 | #define ELF_MACHINE_NO_REL 1 | |
162 | ||
99c7f870 | 163 | /* Set up the loaded object described by MAP so its unrelocated PLT |
5929563f UD |
164 | entries will jump to the on-demand fixup code in dl-runtime.c. |
165 | Also install a small trampoline to be used by entries that have | |
166 | been relocated to an address too far away for a single branch. */ | |
052b6a6c UD |
167 | extern int __elf_machine_runtime_setup (struct link_map *map, |
168 | int lazy, int profile); | |
99c7f870 UD |
169 | |
170 | static inline int | |
171 | elf_machine_runtime_setup (struct link_map *map, | |
172 | int lazy, int profile) | |
173 | { | |
174 | if (map->l_info[DT_JMPREL] == 0) | |
175 | return lazy; | |
176 | ||
177 | if (map->l_info[DT_PPC(GOT)] == 0) | |
178 | /* Handle old style PLT. */ | |
179 | return __elf_machine_runtime_setup (map, lazy, profile); | |
180 | ||
181 | /* New style non-exec PLT consisting of an array of addresses. */ | |
182 | map->l_info[DT_PPC(GOT)]->d_un.d_ptr += map->l_addr; | |
183 | if (lazy) | |
184 | { | |
185 | Elf32_Addr *plt, *got, glink; | |
186 | Elf32_Word num_plt_entries; | |
187 | void (*dlrr) (void); | |
188 | extern void _dl_runtime_resolve (void); | |
189 | extern void _dl_prof_resolve (void); | |
190 | ||
191 | if (__builtin_expect (!profile, 1)) | |
192 | dlrr = _dl_runtime_resolve; | |
193 | else | |
194 | { | |
195 | if (GLRO(dl_profile) != NULL | |
196 | &&_dl_name_match_p (GLRO(dl_profile), map)) | |
197 | GL(dl_profile_map) = map; | |
198 | dlrr = _dl_prof_resolve; | |
199 | } | |
200 | got = (Elf32_Addr *) map->l_info[DT_PPC(GOT)]->d_un.d_ptr; | |
201 | glink = got[1]; | |
202 | got[1] = (Elf32_Addr) dlrr; | |
203 | got[2] = (Elf32_Addr) map; | |
204 | ||
205 | /* Relocate everything in .plt by the load address offset. */ | |
206 | plt = (Elf32_Addr *) D_PTR (map, l_info[DT_PLTGOT]); | |
207 | num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val | |
208 | / sizeof (Elf32_Rela)); | |
209 | ||
210 | /* If a library is prelinked but we have to relocate anyway, | |
211 | we have to be able to undo the prelinking of .plt section. | |
212 | The prelinker saved us at got[1] address of .glink | |
213 | section's start. */ | |
214 | if (glink) | |
215 | { | |
216 | glink += map->l_addr; | |
217 | while (num_plt_entries-- != 0) | |
218 | *plt++ = glink, glink += 4; | |
219 | } | |
220 | else | |
221 | while (num_plt_entries-- != 0) | |
222 | *plt++ += map->l_addr; | |
223 | } | |
224 | return lazy; | |
225 | } | |
5929563f | 226 | |
052b6a6c | 227 | /* Change the PLT entry whose reloc is 'reloc' to call the actual routine. */ |
c0282c06 UD |
228 | extern Elf32_Addr __elf_machine_fixup_plt (struct link_map *map, |
229 | const Elf32_Rela *reloc, | |
230 | Elf32_Addr *reloc_addr, | |
231 | Elf32_Addr finaladdr); | |
232 | ||
233 | static inline Elf32_Addr | |
b6299091 | 234 | elf_machine_fixup_plt (struct link_map *map, lookup_t t, |
c0282c06 | 235 | const Elf32_Rela *reloc, |
b6299091 | 236 | Elf32_Addr *reloc_addr, Elf64_Addr finaladdr) |
c0282c06 | 237 | { |
99c7f870 UD |
238 | if (map->l_info[DT_PPC(GOT)] == 0) |
239 | /* Handle old style PLT. */ | |
240 | return __elf_machine_fixup_plt (map, reloc, reloc_addr, finaladdr); | |
241 | ||
242 | *reloc_addr = finaladdr; | |
243 | return finaladdr; | |
c0282c06 | 244 | } |
a2b08ee5 | 245 | |
dfd2257a | 246 | /* Return the final value of a plt relocation. */ |
c2a32973 | 247 | static inline Elf32_Addr |
dfd2257a UD |
248 | elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc, |
249 | Elf32_Addr value) | |
250 | { | |
251 | return value + reloc->r_addend; | |
252 | } | |
253 | ||
2413fdba UD |
254 | |
255 | /* Names of the architecture-specific auditing callback functions. */ | |
256 | #define ARCH_LA_PLTENTER ppc32_gnu_pltenter | |
257 | #define ARCH_LA_PLTEXIT ppc32_gnu_pltexit | |
258 | ||
1f205a47 | 259 | #endif /* dl_machine_h */ |
4cca6b86 | 260 | |
2413fdba | 261 | #ifdef RESOLVE_MAP |
4cca6b86 | 262 | |
052b6a6c UD |
263 | /* Do the actual processing of a reloc, once its target address |
264 | has been determined. */ | |
265 | extern void __process_machine_rela (struct link_map *map, | |
266 | const Elf32_Rela *reloc, | |
545dbc93 | 267 | struct link_map *sym_map, |
052b6a6c UD |
268 | const Elf32_Sym *sym, |
269 | const Elf32_Sym *refsym, | |
270 | Elf32_Addr *const reloc_addr, | |
271 | Elf32_Addr finaladdr, | |
7551556f RM |
272 | int rinfo) attribute_hidden; |
273 | ||
274 | /* Call _dl_signal_error when a resolved value overflows a relocated area. */ | |
275 | extern void _dl_reloc_overflow (struct link_map *map, | |
276 | const char *name, | |
277 | Elf32_Addr *const reloc_addr, | |
7551556f | 278 | const Elf32_Sym *refsym) attribute_hidden; |
052b6a6c | 279 | |
1f205a47 UD |
280 | /* Perform the relocation specified by RELOC and SYM (which is fully resolved). |
281 | LOADADDR is the load address of the object; INFO is an array indexed | |
282 | by DT_* of the .dynamic section info. */ | |
4cca6b86 | 283 | |
7de00121 | 284 | auto inline void __attribute__ ((always_inline)) |
1f205a47 | 285 | elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, |
3996f34b | 286 | const Elf32_Sym *sym, const struct r_found_version *version, |
87d254a7 | 287 | void *const reloc_addr_arg) |
1f205a47 | 288 | { |
87d254a7 | 289 | Elf32_Addr *const reloc_addr = reloc_addr_arg; |
1f205a47 | 290 | const Elf32_Sym *const refsym = sym; |
bb0ddc2f RM |
291 | Elf32_Addr value; |
292 | const int r_type = ELF32_R_TYPE (reloc->r_info); | |
545dbc93 | 293 | struct link_map *sym_map = NULL; |
4cca6b86 | 294 | |
aa3f2410 | 295 | #ifndef RESOLVE_CONFLICT_FIND_MAP |
bb0ddc2f | 296 | if (r_type == R_PPC_RELATIVE) |
1f205a47 | 297 | { |
bb0ddc2f RM |
298 | *reloc_addr = map->l_addr + reloc->r_addend; |
299 | return; | |
1f205a47 | 300 | } |
bb0ddc2f RM |
301 | |
302 | if (__builtin_expect (r_type == R_PPC_NONE, 0)) | |
303 | return; | |
304 | ||
213cdddb RM |
305 | /* binutils on ppc32 includes st_value in r_addend for relocations |
306 | against local symbols. */ | |
307 | if (__builtin_expect (ELF32_ST_BIND (sym->st_info) == STB_LOCAL, 0) | |
308 | && sym->st_shndx != SHN_UNDEF) | |
309 | value = map->l_addr; | |
310 | else | |
311 | { | |
213cdddb | 312 | sym_map = RESOLVE_MAP (&sym, version, r_type); |
d026cf5f | 313 | value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value; |
213cdddb | 314 | } |
bb0ddc2f | 315 | value += reloc->r_addend; |
aa3f2410 UD |
316 | #else |
317 | value = reloc->r_addend; | |
318 | #endif | |
4cca6b86 | 319 | |
052b6a6c UD |
320 | /* A small amount of code is duplicated here for speed. In libc, |
321 | more than 90% of the relocs are R_PPC_RELATIVE; in the X11 shared | |
322 | libraries, 60% are R_PPC_RELATIVE, 24% are R_PPC_GLOB_DAT or | |
323 | R_PPC_ADDR32, and 16% are R_PPC_JMP_SLOT (which this routine | |
324 | wouldn't usually handle). As an bonus, doing this here allows | |
325 | the switch statement in __process_machine_rela to work. */ | |
bb0ddc2f | 326 | switch (r_type) |
1f205a47 | 327 | { |
bb0ddc2f RM |
328 | case R_PPC_GLOB_DAT: |
329 | case R_PPC_ADDR32: | |
330 | *reloc_addr = value; | |
331 | break; | |
332 | ||
32c075e1 | 333 | #if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD) \ |
545dbc93 | 334 | && !defined RESOLVE_CONFLICT_FIND_MAP |
7551556f RM |
335 | # ifdef RTLD_BOOTSTRAP |
336 | # define NOT_BOOTSTRAP 0 | |
337 | # else | |
338 | # define NOT_BOOTSTRAP 1 | |
bb0ddc2f | 339 | # endif |
7551556f | 340 | |
545dbc93 RM |
341 | case R_PPC_DTPMOD32: |
342 | if (!NOT_BOOTSTRAP) | |
343 | /* During startup the dynamic linker is always index 1. */ | |
344 | *reloc_addr = 1; | |
345 | else if (sym_map != NULL) | |
346 | /* Get the information from the link map returned by the | |
347 | RESOLVE_MAP function. */ | |
348 | *reloc_addr = sym_map->l_tls_modid; | |
349 | break; | |
350 | case R_PPC_DTPREL32: | |
351 | /* During relocation all TLS symbols are defined and used. | |
352 | Therefore the offset is already correct. */ | |
353 | if (NOT_BOOTSTRAP && sym_map != NULL) | |
354 | *reloc_addr = TLS_DTPREL_VALUE (sym, reloc); | |
355 | break; | |
356 | case R_PPC_TPREL32: | |
357 | if (!NOT_BOOTSTRAP || sym_map != NULL) | |
bb0ddc2f | 358 | { |
545dbc93 RM |
359 | if (NOT_BOOTSTRAP) |
360 | CHECK_STATIC_TLS (map, sym_map); | |
361 | *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc); | |
bb0ddc2f | 362 | } |
545dbc93 | 363 | break; |
32c075e1 | 364 | #endif /* USE_TLS etc. */ |
bb0ddc2f | 365 | |
a334319f | 366 | case R_PPC_JMP_SLOT: |
99c7f870 | 367 | #ifdef RESOLVE_CONFLICT_FIND_MAP |
bb0ddc2f | 368 | RESOLVE_CONFLICT_FIND_MAP (map, reloc_addr); |
a334319f | 369 | #endif |
99c7f870 UD |
370 | if (map->l_info[DT_PPC(GOT)] != 0) |
371 | { | |
372 | *reloc_addr = value; | |
373 | break; | |
374 | } | |
375 | /* FALLTHROUGH */ | |
bb0ddc2f RM |
376 | |
377 | default: | |
545dbc93 | 378 | __process_machine_rela (map, reloc, sym_map, sym, refsym, |
bb0ddc2f | 379 | reloc_addr, value, r_type); |
1f205a47 | 380 | } |
1f205a47 UD |
381 | } |
382 | ||
7de00121 | 383 | auto inline void __attribute__ ((always_inline)) |
1f2a1df3 | 384 | elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc, |
87d254a7 | 385 | void *const reloc_addr_arg) |
1721af3f | 386 | { |
87d254a7 | 387 | Elf32_Addr *const reloc_addr = reloc_addr_arg; |
1721af3f UD |
388 | *reloc_addr = l_addr + reloc->r_addend; |
389 | } | |
1f205a47 | 390 | |
7de00121 | 391 | auto inline void __attribute__ ((always_inline)) |
7ba7c829 UD |
392 | elf_machine_lazy_rel (struct link_map *map, |
393 | Elf32_Addr l_addr, const Elf32_Rela *reloc) | |
394 | { | |
395 | /* elf_machine_runtime_setup handles this. */ | |
396 | } | |
397 | ||
052b6a6c UD |
398 | /* The SVR4 ABI specifies that the JMPREL relocs must be inside the |
399 | DT_RELA table. */ | |
400 | #define ELF_MACHINE_PLTREL_OVERLAP 1 | |
401 | ||
2413fdba | 402 | #endif /* RESOLVE_MAP */ |