1 /* Machine-dependent ELF dynamic relocation inline functions. MIPS version.
2 Copyright (C) 1996-2023 Free Software Foundation, Inc.
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
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.
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
13 Lesser General Public License for more details.
14
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 <https://www.gnu.org/licenses/>. */
18
19 /* FIXME: Profiling of shared libraries is not implemented yet. */
20 #ifndef dl_machine_h
21 #define dl_machine_h
22
23 #define ELF_MACHINE_NAME "MIPS"
24
25 #include <entry.h>
26
27 #ifndef ENTRY_POINT
28 #error ENTRY_POINT needs to be defined for MIPS.
29 #endif
30
31 #include <sgidefs.h>
32 #include <sysdep.h>
33 #include <sys/asm.h>
34 #include <dl-tls.h>
35 #include <dl-static-tls.h>
36 #include <dl-machine-rel.h>
37
38 /* The offset of gp from GOT might be system-dependent. It's set by
39 ld. The same value is also */
40 #define OFFSET_GP_GOT 0x7ff0
41
42 #ifndef _RTLD_PROLOGUE
43 # define _RTLD_PROLOGUE(entry) \
44 ".globl\t" __STRING(entry) "\n\t" \
45 ".ent\t" __STRING(entry) "\n\t" \
46 ".type\t" __STRING(entry) ", @function\n" \
47 __STRING(entry) ":\n\t"
48 #endif
49
50 #ifndef _RTLD_EPILOGUE
51 # define _RTLD_EPILOGUE(entry) \
52 ".end\t" __STRING(entry) "\n\t" \
53 ".size\t" __STRING(entry) ", . - " __STRING(entry) "\n\t"
54 #endif
55
56 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.
57 This only makes sense on MIPS when using PLTs, so choose the
58 PLT relocation (not encountered when not using PLTs). */
59 #define ELF_MACHINE_JMP_SLOT R_MIPS_JUMP_SLOT
60 #define elf_machine_type_class(type) \
61 ((((type) == ELF_MACHINE_JMP_SLOT) * ELF_RTYPE_CLASS_PLT) \
62 | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
63
64 #if ((defined __mips_nan2008 && !defined HAVE_MIPS_NAN2008) \
65 || (!defined __mips_nan2008 && defined HAVE_MIPS_NAN2008))
66 # error "Configuration inconsistency: __mips_nan2008 != HAVE_MIPS_NAN2008, overridden CFLAGS?"
67 #endif
68 #ifdef __mips_nan2008
69 # define ELF_MACHINE_NAN2008 EF_MIPS_NAN2008
70 #else
71 # define ELF_MACHINE_NAN2008 0
72 #endif
73
74 /* Return nonzero iff ELF header is compatible with the running host. */
75 static inline int __attribute_used__
76 elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
77 {
78 #if _MIPS_SIM == _ABIO32 || _MIPS_SIM == _ABIN32
79 /* Don't link o32 and n32 together. */
80 if (((ehdr->e_flags & EF_MIPS_ABI2) != 0) != (_MIPS_SIM == _ABIN32))
81 return 0;
82 #endif
83
84 /* Don't link 2008-NaN and legacy-NaN objects together. */
85 if ((ehdr->e_flags & EF_MIPS_NAN2008) != ELF_MACHINE_NAN2008)
86 return 0;
87
88 /* Ensure that the old O32 FP64 ABI is never loaded, it is not supported
89 on linux. */
90 if (ehdr->e_flags & EF_MIPS_FP64)
91 return 0;
92
93 switch (ehdr->e_machine)
94 {
95 case EM_MIPS:
96 case EM_MIPS_RS3_LE:
97 return 1;
98 default:
99 return 0;
100 }
101 }
102
103 static inline ElfW(Addr) *
104 elf_mips_got_from_gpreg (ElfW(Addr) gpreg)
105 {
106 /* FIXME: the offset of gp from GOT may be system-dependent. */
107 return (ElfW(Addr) *) (gpreg - OFFSET_GP_GOT);
108 }
109
110 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
111 first element of the GOT. This must be inlined in a function which
112 uses global data. We assume its $gp points to the primary GOT. */
113 static inline ElfW(Addr)
114 elf_machine_dynamic (void)
115 {
116 register ElfW(Addr) gp __asm__ ("$28");
117 return *elf_mips_got_from_gpreg (gp);
118 }
119
120 #define STRINGXP(X) __STRING(X)
121 #define STRINGXV(X) STRINGV_(X)
122 #define STRINGV_(...) # __VA_ARGS__
123
124 /* Return the run-time load address of the shared object. */
125 static inline ElfW(Addr)
126 elf_machine_load_address (void)
127 {
128 ElfW(Addr) addr;
129 #ifndef __mips16
130 asm (" .set noreorder\n"
131 " " STRINGXP (PTR_LA) " %0, 0f\n"
132 # if !defined __mips_isa_rev || __mips_isa_rev < 6
133 " bltzal $0, 0f\n"
134 " nop\n"
135 "0: " STRINGXP (PTR_SUBU) " %0, $31, %0\n"
136 # else
137 "0: addiupc $31, 0\n"
138 " " STRINGXP (PTR_SUBU) " %0, $31, %0\n"
139 # endif
140 " .set reorder\n"
141 : "=r" (addr)
142 : /* No inputs */
143 : "$31");
144 #else
145 ElfW(Addr) tmp;
146 asm (" .set noreorder\n"
147 " move %1,$gp\n"
148 " lw %1,%%got(0f)(%1)\n"
149 "0: .fill 0\n" /* Clear the ISA bit on 0:. */
150 " la %0,0b\n"
151 " addiu %1,%%lo(0b)\n"
152 " subu %0,%1\n"
153 " .set reorder\n"
154 : "=d" (addr), "=d" (tmp)
155 : /* No inputs */);
156 #endif
157 return addr;
158 }
159
160 /* The MSB of got[1] of a gnu object is set to identify gnu objects. */
161 #if _MIPS_SIM == _ABI64
162 # define ELF_MIPS_GNU_GOT1_MASK 0x8000000000000000L
163 #else
164 # define ELF_MIPS_GNU_GOT1_MASK 0x80000000L
165 #endif
166
167 /* We can't rely on elf_machine_got_rel because _dl_object_relocation_scope
168 fiddles with global data. */
169 #define ELF_MACHINE_BEFORE_RTLD_RELOC(bootstrap_map, dynamic_info) \
170 do { \
171 struct link_map *map = bootstrap_map; \
172 ElfW(Sym) *sym; \
173 ElfW(Addr) *got; \
174 int i, n; \
175 \
176 got = (ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]); \
177 \
178 if (__builtin_expect (map->l_addr == 0, 1)) \
179 break; \
180 \
181 /* got[0] is reserved. got[1] is also reserved for the dynamic object \
182 generated by gnu ld. Skip these reserved entries from \
183 relocation. */ \
184 i = (got[1] & ELF_MIPS_GNU_GOT1_MASK)? 2 : 1; \
185 n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val; \
186 \
187 /* Add the run-time displacement to all local got entries. */ \
188 while (i < n) \
189 got[i++] += map->l_addr; \
190 \
191 /* Handle global got entries. */ \
192 got += n; \
193 sym = (ElfW(Sym) *) D_PTR(map, l_info[DT_SYMTAB]) \
194 + map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val; \
195 i = (map->l_info[DT_MIPS (SYMTABNO)]->d_un.d_val \
196 - map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val); \
197 \
198 while (i--) \
199 { \
200 if (sym->st_shndx == SHN_UNDEF || sym->st_shndx == SHN_COMMON) \
201 *got = SYMBOL_ADDRESS (map, sym, true); \
202 else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC \
203 && *got != sym->st_value) \
204 *got += map->l_addr; \
205 else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION) \
206 { \
207 if (sym->st_other == 0) \
208 *got += map->l_addr; \
209 } \
210 else \
211 *got = SYMBOL_ADDRESS (map, sym, true); \
212 \
213 got++; \
214 sym++; \
215 } \
216 } while(0)
217
218
219 /* Mask identifying addresses reserved for the user program,
220 where the dynamic linker should not map anything. */
221 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
222
223
224 /* Initial entry point code for the dynamic linker.
225 The C function `_dl_start' is the real entry point;
226 its return value is the user program's entry point.
227 Note how we have to be careful about two things:
228
229 1) That we allocate a minimal stack of 24 bytes for
230 every function call, the MIPS ABI states that even
231 if all arguments are passed in registers the procedure
232 called can use the 16 byte area pointed to by $sp
233 when it is called to store away the arguments passed
234 to it.
235
236 2) That under Unix the entry is named __start
237 and not just plain _start. */
238
239 #ifndef __mips16
240 # if !defined __mips_isa_rev || __mips_isa_rev < 6
241 # define LCOFF STRINGXP(.Lcof2)
242 # define LOAD_31 STRINGXP(bltzal $8) "," STRINGXP(.Lcof2)
243 # else
244 # define LCOFF STRINGXP(.Lcof1)
245 # define LOAD_31 "addiupc $31, 0"
246 # endif
247 # define RTLD_START asm (\
248 ".text\n\
249 " _RTLD_PROLOGUE(ENTRY_POINT) "\
250 " STRINGXV(SETUP_GPX($25)) "\n\
251 " STRINGXV(SETUP_GPX64($18,$25)) "\n\
252 # i386 ABI book says that the first entry of GOT holds\n\
253 # the address of the dynamic structure. Though MIPS ABI\n\
254 # doesn't say nothing about this, I emulate this here.\n\
255 " STRINGXP(PTR_LA) " $4, _DYNAMIC\n\
256 # Subtract OFFSET_GP_GOT\n\
257 " STRINGXP(PTR_S) " $4, -0x7ff0($28)\n\
258 move $4, $29\n\
259 " STRINGXP(PTR_SUBIU) " $29, 16\n\
260 \n\
261 " STRINGXP(PTR_LA) " $8, " LCOFF "\n\
262 .Lcof1: " LOAD_31 "\n\
263 .Lcof2: " STRINGXP(PTR_SUBU) " $8, $31, $8\n\
264 \n\
265 " STRINGXP(PTR_LA) " $25, _dl_start\n\
266 " STRINGXP(PTR_ADDU) " $25, $8\n\
267 jalr $25\n\
268 \n\
269 " STRINGXP(PTR_ADDIU) " $29, 16\n\
270 # Get the value of label '_dl_start_user' in t9 ($25).\n\
271 " STRINGXP(PTR_LA) " $25, _dl_start_user\n\
272 " _RTLD_EPILOGUE(ENTRY_POINT) "\
273 \n\
274 \n\
275 " _RTLD_PROLOGUE(_dl_start_user) "\
276 " STRINGXP(SETUP_GP) "\n\
277 " STRINGXV(SETUP_GP64($18,_dl_start_user)) "\n\
278 move $16, $28\n\
279 # Save the user entry point address in a saved register.\n\
280 move $17, $2\n\
281 # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
282 " STRINGXP(PTR_L) " $4, _rtld_local\n\
283 " STRINGXP(PTR_L) /* or lw??? fixme */ " $5, 0($29)\n\
284 " STRINGXP(PTR_LA) " $6, " STRINGXP (PTRSIZE) "($29)\n\
285 sll $7, $5, " STRINGXP (PTRLOG) "\n\
286 " STRINGXP(PTR_ADDU) " $7, $7, $6\n\
287 " STRINGXP(PTR_ADDU) " $7, $7, " STRINGXP (PTRSIZE) " \n\
288 # Make sure the stack pointer is aligned for _dl_init.\n\
289 and $2, $29, -2 * " STRINGXP(SZREG) "\n\
290 move $8, $29\n\
291 " STRINGXP(PTR_SUBIU) " $29, $2, 32\n\
292 " STRINGXP(PTR_S) " $8, (32 - " STRINGXP(SZREG) ")($29)\n\
293 " STRINGXP(SAVE_GP(16)) "\n\
294 # Call the function to run the initializers.\n\
295 jal _dl_init\n\
296 # Restore the stack pointer for _start.\n\
297 " STRINGXP(PTR_L) " $29, (32 - " STRINGXP(SZREG) ")($29)\n\
298 # Pass our finalizer function to the user in $2 as per ELF ABI.\n\
299 " STRINGXP(PTR_LA) " $2, _dl_fini\n\
300 # Jump to the user entry point.\n\
301 move $25, $17\n\
302 jr $25\n\t"\
303 _RTLD_EPILOGUE(_dl_start_user)\
304 ".previous"\
305 );
306
307 #else /* __mips16 */
308 /* MIPS16 version. We currently only support O32 under MIPS16; the proper
309 assembly preprocessor abstractions will need to be added if other ABIs
310 are to be supported. */
311
312 # define RTLD_START asm (\
313 ".text\n\
314 .set mips16\n\
315 " _RTLD_PROLOGUE (ENTRY_POINT) "\
316 # Construct GP value in $3.\n\
317 li $3, %hi(_gp_disp)\n\
318 addiu $4, $pc, %lo(_gp_disp)\n\
319 sll $3, 16\n\
320 addu $3, $4\n\
321 move $28, $3\n\
322 lw $4, %got(_DYNAMIC)($3)\n\
323 sw $4, -0x7ff0($3)\n\
324 move $4, $sp\n\
325 addiu $sp, -16\n\
326 # _dl_start() is sufficiently near to use pc-relative\n\
327 # load address.\n\
328 la $3, _dl_start\n\
329 move $25, $3\n\
330 jalr $3\n\
331 addiu $sp, 16\n\
332 " _RTLD_EPILOGUE (ENTRY_POINT) "\
333 \n\
334 \n\
335 " _RTLD_PROLOGUE (_dl_start_user) "\
336 li $16, %hi(_gp_disp)\n\
337 addiu $4, $pc, %lo(_gp_disp)\n\
338 sll $16, 16\n\
339 addu $16, $4\n\
340 move $17, $2\n\
341 move $28, $16\n\
342 # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
343 lw $4, %got(_rtld_local)($16)\n\
344 lw $4, 0($4)\n\
345 lw $5, 0($sp)\n\
346 addiu $6, $sp, " STRINGXP (PTRSIZE) "\n\
347 sll $7, $5, " STRINGXP (PTRLOG) "\n\
348 addu $7, $6\n\
349 addu $7, " STRINGXP (PTRSIZE) "\n\
350 # Make sure the stack pointer is aligned for _dl_init.\n\
351 li $2, 2 * " STRINGXP (SZREG) "\n\
352 neg $2, $2\n\
353 move $3, $sp\n\
354 and $2, $3\n\
355 sw $3, -" STRINGXP (SZREG) "($2)\n\
356 addiu $2, -32\n\
357 move $sp, $2\n\
358 sw $16, 16($sp)\n\
359 # Call the function to run the initializers.\n\
360 lw $2, %call16(_dl_init)($16)\n\
361 move $25, $2\n\
362 jalr $2\n\
363 # Restore the stack pointer for _start.\n\
364 lw $2, 32-" STRINGXP (SZREG) "($sp)\n\
365 move $sp, $2\n\
366 move $28, $16\n\
367 # Pass our finalizer function to the user in $2 as per ELF ABI.\n\
368 lw $2, %call16(_dl_fini)($16)\n\
369 # Jump to the user entry point.\n\
370 move $25, $17\n\
371 jr $17\n\t"\
372 _RTLD_EPILOGUE (_dl_start_user)\
373 ".previous"\
374 );
375
376 #endif /* __mips16 */
377
378 /* Names of the architecture-specific auditing callback functions. */
379 # if _MIPS_SIM == _ABIO32
380 # define ARCH_LA_PLTENTER mips_o32_gnu_pltenter
381 # define ARCH_LA_PLTEXIT mips_o32_gnu_pltexit
382 # elif _MIPS_SIM == _ABIN32
383 # define ARCH_LA_PLTENTER mips_n32_gnu_pltenter
384 # define ARCH_LA_PLTEXIT mips_n32_gnu_pltexit
385 # else
386 # define ARCH_LA_PLTENTER mips_n64_gnu_pltenter
387 # define ARCH_LA_PLTEXIT mips_n64_gnu_pltexit
388 # endif
389
390 /* We define an initialization function. This is called very early in
391 _dl_sysdep_start. */
392 #define DL_PLATFORM_INIT dl_platform_init ()
393
394 static inline void __attribute__ ((unused))
395 dl_platform_init (void)
396 {
397 if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
398 /* Avoid an empty string which would disturb us. */
399 GLRO(dl_platform) = NULL;
400 }
401
402 /* For a non-writable PLT, rewrite the .got.plt entry at RELOC_ADDR to
403 point at the symbol with address VALUE. For a writable PLT, rewrite
404 the corresponding PLT entry instead. */
405 static inline ElfW(Addr)
406 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
407 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
408 const ElfW(Rel) *reloc,
409 ElfW(Addr) *reloc_addr, ElfW(Addr) value)
410 {
411 return *reloc_addr = value;
412 }
413
414 static inline ElfW(Addr)
415 elf_machine_plt_value (struct link_map *map, const ElfW(Rel) *reloc,
416 ElfW(Addr) value)
417 {
418 return value;
419 }
420
421 #endif /* !dl_machine_h */
422
423 #ifdef RESOLVE_MAP
424
425 /* Perform a relocation described by R_INFO at the location pointed to
426 by RELOC_ADDR. SYM is the relocation symbol specified by R_INFO and
427 MAP is the object containing the reloc. */
428
429 static inline void
430 __attribute__ ((always_inline))
431 elf_machine_reloc (struct link_map *map, struct r_scope_elem *scope[],
432 ElfW(Addr) r_info, const ElfW(Sym) *sym,
433 const struct r_found_version *version, void *reloc_addr,
434 ElfW(Addr) r_addend, int inplace_p)
435 {
436 const unsigned long int r_type = ELFW(R_TYPE) (r_info);
437 ElfW(Addr) *addr_field = (ElfW(Addr) *) reloc_addr;
438
439 #if !defined RTLD_BOOTSTRAP && !defined SHARED
440 /* This is defined in rtld.c, but nowhere in the static libc.a;
441 make the reference weak so static programs can still link. This
442 declaration cannot be done when compiling rtld.c (i.e. #ifdef
443 RTLD_BOOTSTRAP) because rtld.c contains the common defn for
444 _dl_rtld_map, which is incompatible with a weak decl in the same
445 file. */
446 weak_extern (GL(dl_rtld_map));
447 #endif
448
449 switch (r_type)
450 {
451 #if !defined (RTLD_BOOTSTRAP)
452 # if _MIPS_SIM == _ABI64
453 case R_MIPS_TLS_DTPMOD64:
454 case R_MIPS_TLS_DTPREL64:
455 case R_MIPS_TLS_TPREL64:
456 # else
457 case R_MIPS_TLS_DTPMOD32:
458 case R_MIPS_TLS_DTPREL32:
459 case R_MIPS_TLS_TPREL32:
460 # endif
461 {
462 struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
463 r_type);
464
465 switch (r_type)
466 {
467 case R_MIPS_TLS_DTPMOD64:
468 case R_MIPS_TLS_DTPMOD32:
469 if (sym_map)
470 *addr_field = sym_map->l_tls_modid;
471 break;
472
473 case R_MIPS_TLS_DTPREL64:
474 case R_MIPS_TLS_DTPREL32:
475 if (sym)
476 {
477 if (inplace_p)
478 r_addend = *addr_field;
479 *addr_field = r_addend + TLS_DTPREL_VALUE (sym);
480 }
481 break;
482
483 case R_MIPS_TLS_TPREL32:
484 case R_MIPS_TLS_TPREL64:
485 if (sym)
486 {
487 CHECK_STATIC_TLS (map, sym_map);
488 if (inplace_p)
489 r_addend = *addr_field;
490 *addr_field = r_addend + TLS_TPREL_VALUE (sym_map, sym);
491 }
492 break;
493 }
494
495 break;
496 }
497 #endif
498
499 #if _MIPS_SIM == _ABI64
500 case (R_MIPS_64 << 8) | R_MIPS_REL32:
501 #else
502 case R_MIPS_REL32:
503 #endif
504 {
505 int symidx = ELFW(R_SYM) (r_info);
506 ElfW(Addr) reloc_value;
507
508 if (inplace_p)
509 /* Support relocations on mis-aligned offsets. */
510 __builtin_memcpy (&reloc_value, reloc_addr, sizeof (reloc_value));
511 else
512 reloc_value = r_addend;
513
514 if (symidx)
515 {
516 const ElfW(Word) gotsym
517 = (const ElfW(Word)) map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
518
519 if ((ElfW(Word))symidx < gotsym)
520 {
521 /* This wouldn't work for a symbol imported from other
522 libraries for which there's no GOT entry, but MIPS
523 requires every symbol referenced in a dynamic
524 relocation to have a GOT entry in the primary GOT,
525 so we only get here for locally-defined symbols.
526 For section symbols, we should *NOT* be adding
527 sym->st_value (per the definition of the meaning of
528 S in reloc expressions in the ELF64 MIPS ABI),
529 since it should have already been added to
530 reloc_value by the linker, but older versions of
531 GNU ld didn't add it, and newer versions don't emit
532 useless relocations to section symbols any more, so
533 it is safe to keep on adding sym->st_value, even
534 though it's not ABI compliant. Some day we should
535 bite the bullet and stop doing this. */
536 #ifndef RTLD_BOOTSTRAP
537 if (map != &GL(dl_rtld_map))
538 #endif
539 reloc_value += SYMBOL_ADDRESS (map, sym, true);
540 }
541 else
542 {
543 #ifndef RTLD_BOOTSTRAP
544 const ElfW(Addr) *got
545 = (const ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);
546 const ElfW(Word) local_gotno
547 = (const ElfW(Word))
548 map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
549
550 reloc_value += got[symidx + local_gotno - gotsym];
551 #endif
552 }
553 }
554 else
555 #ifndef RTLD_BOOTSTRAP
556 if (map != &GL(dl_rtld_map))
557 #endif
558 reloc_value += map->l_addr;
559
560 __builtin_memcpy (reloc_addr, &reloc_value, sizeof (reloc_value));
561 }
562 break;
563 #ifndef RTLD_BOOTSTRAP
564 #if _MIPS_SIM == _ABI64
565 case (R_MIPS_64 << 8) | R_MIPS_GLOB_DAT:
566 #else
567 case R_MIPS_GLOB_DAT:
568 #endif
569 {
570 int symidx = ELFW(R_SYM) (r_info);
571 const ElfW(Word) gotsym
572 = (const ElfW(Word)) map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
573
574 if (__builtin_expect ((ElfW(Word)) symidx >= gotsym, 1))
575 {
576 const ElfW(Addr) *got
577 = (const ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);
578 const ElfW(Word) local_gotno
579 = ((const ElfW(Word))
580 map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val);
581
582 ElfW(Addr) reloc_value = got[symidx + local_gotno - gotsym];
583 __builtin_memcpy (reloc_addr, &reloc_value, sizeof (reloc_value));
584 }
585 }
586 break;
587 #endif
588 case R_MIPS_NONE: /* Alright, Wilbur. */
589 break;
590
591 case R_MIPS_JUMP_SLOT:
592 {
593 struct link_map *sym_map;
594 ElfW(Addr) value;
595
596 /* The addend for a jump slot relocation must always be zero:
597 calls via the PLT always branch to the symbol's address and
598 not to the address plus a non-zero offset. */
599 if (r_addend != 0)
600 _dl_signal_error (0, map->l_name, NULL,
601 "found jump slot relocation with non-zero addend");
602
603 sym_map = RESOLVE_MAP (map, scope, &sym, version, r_type);
604 value = SYMBOL_ADDRESS (sym_map, sym, true);
605 *addr_field = value;
606
607 break;
608 }
609
610 case R_MIPS_COPY:
611 {
612 const ElfW(Sym) *const refsym = sym;
613 struct link_map *sym_map;
614 ElfW(Addr) value;
615
616 /* Calculate the address of the symbol. */
617 sym_map = RESOLVE_MAP (map, scope, &sym, version, r_type);
618 value = SYMBOL_ADDRESS (sym_map, sym, true);
619
620 if (__builtin_expect (sym == NULL, 0))
621 /* This can happen in trace mode if an object could not be
622 found. */
623 break;
624 if (__builtin_expect (sym->st_size > refsym->st_size, 0)
625 || (__builtin_expect (sym->st_size < refsym->st_size, 0)
626 && GLRO(dl_verbose)))
627 {
628 const char *strtab;
629
630 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
631 _dl_error_printf ("\
632 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
633 RTLD_PROGNAME, strtab + refsym->st_name);
634 }
635 memcpy (reloc_addr, (void *) value,
636 sym->st_size < refsym->st_size
637 ? sym->st_size : refsym->st_size);
638 break;
639 }
640
641 #if _MIPS_SIM == _ABI64
642 case R_MIPS_64:
643 /* For full compliance with the ELF64 ABI, one must precede the
644 _REL32/_64 pair of relocations with a _64 relocation, such
645 that the in-place addend is read as a 64-bit value. IRIX
646 didn't pick up on this requirement, so we treat the
647 _REL32/_64 relocation as a 64-bit relocation even if it's by
648 itself. For ABI compliance, we ignore such _64 dummy
649 relocations. For RELA, this may be simply removed, since
650 it's totally unnecessary. */
651 if (ELFW(R_SYM) (r_info) == 0)
652 break;
653 #endif
654 /* Fall through. */
655 default:
656 _dl_reloc_bad_type (map, r_type, 0);
657 break;
658 }
659 }
660
661 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
662 MAP is the object containing the reloc. */
663
664 static inline void
665 __attribute__ ((always_inline))
666 elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
667 const ElfW(Rel) *reloc, const ElfW(Sym) *sym,
668 const struct r_found_version *version, void *const reloc_addr,
669 int skip_ifunc)
670 {
671 elf_machine_reloc (map, scope, reloc->r_info, sym, version, reloc_addr, 0, 1);
672 }
673
674 static inline void
675 __attribute__((always_inline))
676 elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
677 void *const reloc_addr)
678 {
679 /* XXX Nothing to do. There is no relative relocation, right? */
680 }
681
682 static inline void
683 __attribute__((always_inline))
684 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
685 ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
686 int skip_ifunc)
687 {
688 ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
689 const unsigned int r_type = ELFW(R_TYPE) (reloc->r_info);
690 /* Check for unexpected PLT reloc type. */
691 if (__builtin_expect (r_type == R_MIPS_JUMP_SLOT, 1))
692 {
693 if (__builtin_expect (map->l_mach.plt, 0) == 0)
694 {
695 /* Nothing is required here since we only support lazy
696 relocation in executables. */
697 }
698 else
699 *reloc_addr = map->l_mach.plt;
700 }
701 else
702 _dl_reloc_bad_type (map, r_type, 1);
703 }
704
705 static inline void
706 __attribute__ ((always_inline))
707 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[], const ElfW(Rela) *reloc,
708 const ElfW(Sym) *sym, const struct r_found_version *version,
709 void *const reloc_addr, int skip_ifunc)
710 {
711 elf_machine_reloc (map, scope, reloc->r_info, sym, version, reloc_addr,
712 reloc->r_addend, 0);
713 }
714
715 static inline void
716 __attribute__((always_inline))
717 elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
718 void *const reloc_addr)
719 {
720 }
721
722 #ifndef RTLD_BOOTSTRAP
723 /* Relocate GOT. */
724 static inline void
725 __attribute__((always_inline))
726 elf_machine_got_rel (struct link_map *map, struct r_scope_elem *scope[], int lazy)
727 {
728 ElfW(Addr) *got;
729 ElfW(Sym) *sym;
730 const ElfW(Half) *vernum;
731 int i, n, symidx;
732
733 #define RESOLVE_GOTSYM(sym,vernum,sym_index,reloc) \
734 ({ \
735 const ElfW(Sym) *ref = sym; \
736 const struct r_found_version *version __attribute__ ((unused)) \
737 = vernum ? &map->l_versions[vernum[sym_index] & 0x7fff] : NULL; \
738 struct link_map *sym_map; \
739 sym_map = RESOLVE_MAP (map, scope, &ref, version, reloc); \
740 SYMBOL_ADDRESS (sym_map, ref, true); \
741 })
742
743 if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
744 vernum = (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
745 else
746 vernum = NULL;
747
748 got = (ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);
749
750 n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
751 /* The dynamic linker's local got entries have already been relocated. */
752 if (map != &GL(dl_rtld_map))
753 {
754 /* got[0] is reserved. got[1] is also reserved for the dynamic object
755 generated by gnu ld. Skip these reserved entries from relocation. */
756 i = (got[1] & ELF_MIPS_GNU_GOT1_MASK)? 2 : 1;
757
758 /* Add the run-time displacement to all local got entries if
759 needed. */
760 if (__builtin_expect (map->l_addr != 0, 0))
761 {
762 while (i < n)
763 got[i++] += map->l_addr;
764 }
765 }
766
767 /* Handle global got entries. */
768 got += n;
769 /* Keep track of the symbol index. */
770 symidx = map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
771 sym = (ElfW(Sym) *) D_PTR (map, l_info[DT_SYMTAB]) + symidx;
772 i = (map->l_info[DT_MIPS (SYMTABNO)]->d_un.d_val
773 - map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val);
774
775 /* This loop doesn't handle Quickstart. */
776 while (i--)
777 {
778 if (sym->st_shndx == SHN_UNDEF)
779 {
780 if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC && sym->st_value
781 && !(sym->st_other & STO_MIPS_PLT))
782 {
783 if (lazy)
784 *got = SYMBOL_ADDRESS (map, sym, true);
785 else
786 /* This is a lazy-binding stub, so we don't need the
787 canonical address. */
788 *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_JUMP_SLOT);
789 }
790 else
791 *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
792 }
793 else if (sym->st_shndx == SHN_COMMON)
794 *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
795 else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC
796 && *got != sym->st_value)
797 {
798 if (lazy)
799 *got += map->l_addr;
800 else
801 /* This is a lazy-binding stub, so we don't need the
802 canonical address. */
803 *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_JUMP_SLOT);
804 }
805 else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION)
806 {
807 if (sym->st_other == 0)
808 *got += map->l_addr;
809 }
810 else
811 *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
812
813 ++got;
814 ++sym;
815 ++symidx;
816 }
817
818 #undef RESOLVE_GOTSYM
819 }
820 #endif
821
822 /* Set up the loaded object described by L so its stub function
823 will jump to the on-demand fixup code __dl_runtime_resolve. */
824
825 static inline int
826 __attribute__((always_inline))
827 elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
828 int lazy, int profile)
829 {
830 # ifndef RTLD_BOOTSTRAP
831 ElfW(Addr) *got;
832 extern void _dl_runtime_resolve (ElfW(Word));
833 extern void _dl_runtime_pltresolve (void);
834 extern int _dl_mips_gnu_objects;
835
836 if (lazy)
837 {
838 /* The GOT entries for functions have not yet been filled in.
839 Their initial contents will arrange when called to put an
840 offset into the .dynsym section in t8, the return address
841 in t7 and then jump to _GLOBAL_OFFSET_TABLE[0]. */
842 got = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
843
844 /* This function will get called to fix up the GOT entry indicated by
845 the register t8, and then jump to the resolved address. */
846 got[0] = (ElfW(Addr)) &_dl_runtime_resolve;
847
848 /* Store l to _GLOBAL_OFFSET_TABLE[1] for gnu object. The MSB
849 of got[1] of a gnu object is set to identify gnu objects.
850 Where we can store l for non gnu objects? XXX */
851 if ((got[1] & ELF_MIPS_GNU_GOT1_MASK) != 0)
852 got[1] = ((ElfW(Addr)) l | ELF_MIPS_GNU_GOT1_MASK);
853 else
854 _dl_mips_gnu_objects = 0;
855 }
856
857 /* Relocate global offset table. */
858 elf_machine_got_rel (l, scope, lazy);
859
860 /* If using PLTs, fill in the first two entries of .got.plt. */
861 if (l->l_info[DT_JMPREL] && lazy)
862 {
863 ElfW(Addr) *gotplt;
864 gotplt = (ElfW(Addr) *) D_PTR (l, l_info[DT_MIPS (PLTGOT)]);
865 /* If a library is prelinked but we have to relocate anyway,
866 we have to be able to undo the prelinking of .got.plt.
867 The prelinker saved the address of .plt for us here. */
868 if (gotplt[1])
869 l->l_mach.plt = gotplt[1] + l->l_addr;
870 gotplt[0] = (ElfW(Addr)) &_dl_runtime_pltresolve;
871 gotplt[1] = (ElfW(Addr)) l;
872 }
873
874 # endif
875 return lazy;
876 }
877
878 #endif /* RESOLVE_MAP */