1 /* $NetBSD: mips_reloc.c,v 1.58 2010/01/14 11:57:06 skrll Exp $ */
2
3 /*
4 * Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
5 * Portions copyright 2002 Charles M. Hannum <root@ihack.net>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 * derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/types.h>
35 #include <sys/stat.h>
36 #include <sys/endian.h>
37
38 #include <stdlib.h>
39 #include <string.h>
40 #include <inttypes.h>
41
42 #include <machine/sysarch.h>
43 #include <machine/tls.h>
44
45 #include "debug.h"
46 #include "rtld.h"
47
48 #ifdef __mips_n64
49 #define GOT1_MASK 0x8000000000000000UL
50 #else
51 #define GOT1_MASK 0x80000000UL
52 #endif
53
54 void
init_pltgot(Obj_Entry * obj)55 init_pltgot(Obj_Entry *obj)
56 {
57 if (obj->pltgot != NULL) {
58 obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
59 if (obj->pltgot[1] & 0x80000000)
60 obj->pltgot[1] = (Elf_Addr) obj | GOT1_MASK;
61 }
62 }
63
64 int
do_copy_relocations(Obj_Entry * dstobj)65 do_copy_relocations(Obj_Entry *dstobj)
66 {
67 /* Do nothing */
68 return 0;
69 }
70
71 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
72
73 /*
74 * It is possible for the compiler to emit relocations for unaligned data.
75 * We handle this situation with these inlines.
76 */
77 #ifdef __mips_n64
78 /*
79 * ELF64 MIPS encodes the relocs uniquely. The first 32-bits of info contain
80 * the symbol index. The top 32-bits contain three relocation types encoded
81 * in big-endian integer with first relocation in LSB. This means for little
82 * endian we have to byte swap that integer (r_type).
83 */
84 #define Elf_Sxword Elf64_Sxword
85 #define ELF_R_NXTTYPE_64_P(r_type) ((((r_type) >> 8) & 0xff) == R_TYPE(64))
86 #if BYTE_ORDER == LITTLE_ENDIAN
87 #undef ELF_R_SYM
88 #undef ELF_R_TYPE
89 #define ELF_R_SYM(r_info) ((r_info) & 0xffffffff)
90 #define ELF_R_TYPE(r_info) bswap32((r_info) >> 32)
91 #endif
92 #else
93 #define ELF_R_NXTTYPE_64_P(r_type) (0)
94 #define Elf_Sxword Elf32_Sword
95 #endif
96
97 static __inline Elf_Sxword
load_ptr(void * where,size_t len)98 load_ptr(void *where, size_t len)
99 {
100 Elf_Sxword val;
101
102 if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
103 #ifdef __mips_n64
104 if (len == sizeof(Elf_Sxword))
105 return *(Elf_Sxword *)where;
106 #endif
107 return *(Elf_Sword *)where;
108 }
109
110 val = 0;
111 #if BYTE_ORDER == LITTLE_ENDIAN
112 (void)memcpy(&val, where, len);
113 #endif
114 #if BYTE_ORDER == BIG_ENDIAN
115 (void)memcpy((uint8_t *)((&val)+1) - len, where, len);
116 #endif
117 return (len == sizeof(Elf_Sxword)) ? val : (Elf_Sword)val;
118 }
119
120 static __inline void
store_ptr(void * where,Elf_Sxword val,size_t len)121 store_ptr(void *where, Elf_Sxword val, size_t len)
122 {
123 if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
124 #ifdef __mips_n64
125 if (len == sizeof(Elf_Sxword)) {
126 *(Elf_Sxword *)where = val;
127 return;
128 }
129 #endif
130 *(Elf_Sword *)where = val;
131 return;
132 }
133 #if BYTE_ORDER == LITTLE_ENDIAN
134 (void)memcpy(where, &val, len);
135 #endif
136 #if BYTE_ORDER == BIG_ENDIAN
137 (void)memcpy(where, (const uint8_t *)((&val)+1) - len, len);
138 #endif
139 }
140
141 void
_rtld_relocate_nonplt_self(Elf_Dyn * dynp,Elf_Addr relocbase)142 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
143 {
144 const Elf_Rel *rel = 0, *rellim;
145 Elf_Addr relsz = 0;
146 const Elf_Sym *symtab = NULL, *sym;
147 Elf_Addr *where;
148 Elf_Addr *got = NULL;
149 Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0;
150 size_t i;
151
152 for (; dynp->d_tag != DT_NULL; dynp++) {
153 switch (dynp->d_tag) {
154 case DT_REL:
155 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr);
156 break;
157 case DT_RELSZ:
158 relsz = dynp->d_un.d_val;
159 break;
160 case DT_SYMTAB:
161 symtab = (const Elf_Sym *)(relocbase + dynp->d_un.d_ptr);
162 break;
163 case DT_PLTGOT:
164 got = (Elf_Addr *)(relocbase + dynp->d_un.d_ptr);
165 break;
166 case DT_MIPS_LOCAL_GOTNO:
167 local_gotno = dynp->d_un.d_val;
168 break;
169 case DT_MIPS_SYMTABNO:
170 symtabno = dynp->d_un.d_val;
171 break;
172 case DT_MIPS_GOTSYM:
173 gotsym = dynp->d_un.d_val;
174 break;
175 }
176 }
177
178 i = (got[1] & GOT1_MASK) ? 2 : 1;
179 /* Relocate the local GOT entries */
180 got += i;
181 for (; i < local_gotno; i++) {
182 *got++ += relocbase;
183 }
184
185 sym = symtab + gotsym;
186 /* Now do the global GOT entries */
187 for (i = gotsym; i < symtabno; i++) {
188 *got = sym->st_value + relocbase;
189 ++sym;
190 ++got;
191 }
192
193 rellim = (const Elf_Rel *)((caddr_t)rel + relsz);
194 for (; rel < rellim; rel++) {
195 Elf_Word r_symndx, r_type;
196
197 where = (void *)(relocbase + rel->r_offset);
198
199 r_symndx = ELF_R_SYM(rel->r_info);
200 r_type = ELF_R_TYPE(rel->r_info);
201
202 switch (r_type & 0xff) {
203 case R_TYPE(REL32): {
204 const size_t rlen =
205 ELF_R_NXTTYPE_64_P(r_type)
206 ? sizeof(Elf_Sxword)
207 : sizeof(Elf_Sword);
208 Elf_Sxword old = load_ptr(where, rlen);
209 Elf_Sxword val = old;
210 #ifdef __mips_n64
211 assert(r_type == R_TYPE(REL32)
212 || r_type == (R_TYPE(REL32)|(R_TYPE(64) << 8)));
213 #endif
214 assert(r_symndx < gotsym);
215 sym = symtab + r_symndx;
216 assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL);
217 val += relocbase;
218 store_ptr(where, val, sizeof(Elf_Sword));
219 dbg("REL32/L(%p) %p -> %p in <self>",
220 where, (void *)old, (void *)val);
221 store_ptr(where, val, rlen);
222 break;
223 }
224
225 case R_TYPE(GPREL32):
226 case R_TYPE(NONE):
227 break;
228
229
230 default:
231 abort();
232 break;
233 }
234 }
235 }
236
237 Elf_Addr
_mips_rtld_bind(Obj_Entry * obj,Elf_Size reloff)238 _mips_rtld_bind(Obj_Entry *obj, Elf_Size reloff)
239 {
240 Elf_Addr *got = obj->pltgot;
241 const Elf_Sym *def;
242 const Obj_Entry *defobj;
243 Elf_Addr target;
244
245 def = find_symdef(reloff, obj, &defobj, SYMLOOK_IN_PLT, NULL,
246 NULL);
247 if (def == NULL)
248 rtld_die();
249
250 target = (Elf_Addr)(defobj->relocbase + def->st_value);
251 dbg("bind now/fixup at %s sym # %jd in %s --> was=%p new=%p",
252 obj->path,
253 (intmax_t)reloff, defobj->strtab + def->st_name,
254 (void *)got[obj->local_gotno + reloff - obj->gotsym],
255 (void *)target);
256 got[obj->local_gotno + reloff - obj->gotsym] = target;
257 return (Elf_Addr)target;
258 }
259
260 int
reloc_non_plt(Obj_Entry * obj,Obj_Entry * obj_rtld,int flags,RtldLockState * lockstate)261 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
262 RtldLockState *lockstate)
263 {
264 const Elf_Rel *rel;
265 const Elf_Rel *rellim;
266 Elf_Addr *got = obj->pltgot;
267 const Elf_Sym *sym, *def;
268 const Obj_Entry *defobj;
269 Elf_Word i;
270 #ifdef SUPPORT_OLD_BROKEN_LD
271 int broken;
272 #endif
273
274 /* The relocation for the dynamic loader has already been done. */
275 if (obj == obj_rtld)
276 return (0);
277
278 if ((flags & SYMLOOK_IFUNC) != 0)
279 /* XXX not implemented */
280 return (0);
281
282 #ifdef SUPPORT_OLD_BROKEN_LD
283 broken = 0;
284 sym = obj->symtab;
285 for (i = 1; i < 12; i++)
286 if (sym[i].st_info == ELF_ST_INFO(STB_LOCAL, STT_NOTYPE))
287 broken = 1;
288 dbg("%s: broken=%d", obj->path, broken);
289 #endif
290
291 i = (got[1] & GOT1_MASK) ? 2 : 1;
292
293 /* Relocate the local GOT entries */
294 got += i;
295 dbg("got:%p for %d entries adding %p",
296 got, obj->local_gotno, obj->relocbase);
297 for (; i < obj->local_gotno; i++) {
298 *got += (Elf_Addr)obj->relocbase;
299 got++;
300 }
301 sym = obj->symtab + obj->gotsym;
302
303 dbg("got:%p for %d entries",
304 got, obj->symtabno);
305 /* Now do the global GOT entries */
306 for (i = obj->gotsym; i < obj->symtabno; i++) {
307 dbg(" doing got %d sym %p (%s, %lx)", i - obj->gotsym, sym,
308 sym->st_name + obj->strtab, (u_long) *got);
309
310 #ifdef SUPPORT_OLD_BROKEN_LD
311 if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
312 broken && sym->st_shndx == SHN_UNDEF) {
313 /*
314 * XXX DANGER WILL ROBINSON!
315 * You might think this is stupid, as it intentionally
316 * defeats lazy binding -- and you'd be right.
317 * Unfortunately, for lazy binding to work right, we
318 * need to a way to force the GOT slots used for
319 * function pointers to be resolved immediately. This
320 * is supposed to be done automatically by the linker,
321 * by not outputting a PLT slot and setting st_value
322 * to 0 if there are non-PLT references, but older
323 * versions of GNU ld do not do this.
324 */
325 def = find_symdef(i, obj, &defobj, flags, NULL,
326 lockstate);
327 if (def == NULL)
328 return -1;
329 *got = def->st_value + (Elf_Addr)defobj->relocbase;
330 } else
331 #endif
332 if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
333 sym->st_value != 0 && sym->st_shndx == SHN_UNDEF) {
334 /*
335 * If there are non-PLT references to the function,
336 * st_value should be 0, forcing us to resolve the
337 * address immediately.
338 *
339 * XXX DANGER WILL ROBINSON!
340 * The linker is not outputting PLT slots for calls to
341 * functions that are defined in the same shared
342 * library. This is a bug, because it can screw up
343 * link ordering rules if the symbol is defined in
344 * more than one module. For now, if there is a
345 * definition, we fail the test above and force a full
346 * symbol lookup. This means that all intra-module
347 * calls are bound immediately. - mycroft, 2003/09/24
348 */
349 *got = sym->st_value + (Elf_Addr)obj->relocbase;
350 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
351 dbg("Warning2, i:%d maps to relocbase address:%p",
352 i, obj->relocbase);
353 }
354
355 } else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) {
356 /* Symbols with index SHN_ABS are not relocated. */
357 if (sym->st_shndx != SHN_ABS) {
358 *got = sym->st_value +
359 (Elf_Addr)obj->relocbase;
360 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
361 dbg("Warning3, i:%d maps to relocbase address:%p",
362 i, obj->relocbase);
363 }
364 }
365 } else {
366 /* TODO: add cache here */
367 def = find_symdef(i, obj, &defobj, flags, NULL,
368 lockstate);
369 if (def == NULL) {
370 dbg("Warning4, can't find symbole %d", i);
371 return -1;
372 }
373 *got = def->st_value + (Elf_Addr)defobj->relocbase;
374 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
375 dbg("Warning4, i:%d maps to relocbase address:%p",
376 i, obj->relocbase);
377 dbg("via first obj symbol %s",
378 obj->strtab + obj->symtab[i].st_name);
379 dbg("found in obj %p:%s",
380 defobj, defobj->path);
381 }
382 }
383
384 dbg(" --> now %lx", (u_long) *got);
385 ++sym;
386 ++got;
387 }
388
389 got = obj->pltgot;
390 rellim = (const Elf_Rel *)((caddr_t)obj->rel + obj->relsize);
391 for (rel = obj->rel; rel < rellim; rel++) {
392 Elf_Word r_symndx, r_type;
393 void *where;
394
395 where = obj->relocbase + rel->r_offset;
396 r_symndx = ELF_R_SYM(rel->r_info);
397 r_type = ELF_R_TYPE(rel->r_info);
398
399 switch (r_type & 0xff) {
400 case R_TYPE(NONE):
401 break;
402
403 case R_TYPE(REL32): {
404 /* 32-bit PC-relative reference */
405 const size_t rlen =
406 ELF_R_NXTTYPE_64_P(r_type)
407 ? sizeof(Elf_Sxword)
408 : sizeof(Elf_Sword);
409 Elf_Sxword old = load_ptr(where, rlen);
410 Elf_Sxword val = old;
411
412 def = obj->symtab + r_symndx;
413
414 if (r_symndx >= obj->gotsym) {
415 val += got[obj->local_gotno + r_symndx - obj->gotsym];
416 dbg("REL32/G(%p) %p --> %p (%s) in %s",
417 where, (void *)old, (void *)val,
418 obj->strtab + def->st_name,
419 obj->path);
420 } else {
421 /*
422 * XXX: ABI DIFFERENCE!
423 *
424 * Old NetBSD binutils would generate shared
425 * libs with section-relative relocations being
426 * already adjusted for the start address of
427 * the section.
428 *
429 * New binutils, OTOH, generate shared libs
430 * with the same relocations being based at
431 * zero, so we need to add in the start address
432 * of the section.
433 *
434 * --rkb, Oct 6, 2001
435 */
436
437 if (def->st_info ==
438 ELF_ST_INFO(STB_LOCAL, STT_SECTION)
439 #ifdef SUPPORT_OLD_BROKEN_LD
440 && !broken
441 #endif
442 )
443 val += (Elf_Addr)def->st_value;
444
445 val += (Elf_Addr)obj->relocbase;
446
447 dbg("REL32/L(%p) %p -> %p (%s) in %s",
448 where, (void *)old, (void *)val,
449 obj->strtab + def->st_name, obj->path);
450 }
451 store_ptr(where, val, rlen);
452 break;
453 }
454
455 #ifdef __mips_n64
456 case R_TYPE(TLS_DTPMOD64):
457 #else
458 case R_TYPE(TLS_DTPMOD32):
459 #endif
460 {
461
462 const size_t rlen = sizeof(Elf_Addr);
463 Elf_Addr old = load_ptr(where, rlen);
464 Elf_Addr val = old;
465
466 def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
467 lockstate);
468 if (def == NULL)
469 return -1;
470
471 val += (Elf_Addr)defobj->tlsindex;
472
473 store_ptr(where, val, rlen);
474 dbg("DTPMOD %s in %s %p --> %p in %s",
475 obj->strtab + obj->symtab[r_symndx].st_name,
476 obj->path, (void *)old, (void*)val, defobj->path);
477 break;
478 }
479
480 #ifdef __mips_n64
481 case R_TYPE(TLS_DTPREL64):
482 #else
483 case R_TYPE(TLS_DTPREL32):
484 #endif
485 {
486 const size_t rlen = sizeof(Elf_Addr);
487 Elf_Addr old = load_ptr(where, rlen);
488 Elf_Addr val = old;
489
490 def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
491 lockstate);
492 if (def == NULL)
493 return -1;
494
495 if (!defobj->tls_done && allocate_tls_offset(obj))
496 return -1;
497
498 val += (Elf_Addr)def->st_value - TLS_DTP_OFFSET;
499 store_ptr(where, val, rlen);
500
501 dbg("DTPREL %s in %s %p --> %p in %s",
502 obj->strtab + obj->symtab[r_symndx].st_name,
503 obj->path, (void*)old, (void *)val, defobj->path);
504 break;
505 }
506
507 #ifdef __mips_n64
508 case R_TYPE(TLS_TPREL64):
509 #else
510 case R_TYPE(TLS_TPREL32):
511 #endif
512 {
513 const size_t rlen = sizeof(Elf_Addr);
514 Elf_Addr old = load_ptr(where, rlen);
515 Elf_Addr val = old;
516
517 def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
518 lockstate);
519
520 if (def == NULL)
521 return -1;
522
523 if (!defobj->tls_done && allocate_tls_offset(obj))
524 return -1;
525
526 val += (Elf_Addr)(def->st_value + defobj->tlsoffset
527 - TLS_TP_OFFSET - TLS_TCB_SIZE);
528 store_ptr(where, val, rlen);
529
530 dbg("TPREL %s in %s %p --> %p in %s",
531 obj->strtab + obj->symtab[r_symndx].st_name,
532 obj->path, (void*)old, (void *)val, defobj->path);
533 break;
534 }
535
536
537
538 default:
539 dbg("sym = %lu, type = %lu, offset = %p, "
540 "contents = %p, symbol = %s",
541 (u_long)r_symndx, (u_long)ELF_R_TYPE(rel->r_info),
542 (void *)rel->r_offset,
543 (void *)load_ptr(where, sizeof(Elf_Sword)),
544 obj->strtab + obj->symtab[r_symndx].st_name);
545 _rtld_error("%s: Unsupported relocation type %ld "
546 "in non-PLT relocations",
547 obj->path, (u_long) ELF_R_TYPE(rel->r_info));
548 return -1;
549 }
550 }
551
552 return 0;
553 }
554
555 /*
556 * Process the PLT relocations.
557 */
558 int
reloc_plt(Obj_Entry * obj)559 reloc_plt(Obj_Entry *obj)
560 {
561 #if 0
562 const Elf_Rel *rellim;
563 const Elf_Rel *rel;
564
565 dbg("reloc_plt obj:%p pltrel:%p sz:%s", obj, obj->pltrel, (int)obj->pltrelsize);
566 dbg("gottable %p num syms:%s", obj->pltgot, obj->symtabno );
567 dbg("*****************************************************");
568 rellim = (const Elf_Rel *)((char *)obj->pltrel +
569 obj->pltrelsize);
570 for (rel = obj->pltrel; rel < rellim; rel++) {
571 Elf_Addr *where;
572 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
573 *where += (Elf_Addr )obj->relocbase;
574 }
575
576 #endif
577 /* PLT fixups were done above in the GOT relocation. */
578 return (0);
579 }
580
581 /*
582 * LD_BIND_NOW was set - force relocation for all jump slots
583 */
584 int
reloc_jmpslots(Obj_Entry * obj,int flags,RtldLockState * lockstate)585 reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
586 {
587 /* Do nothing */
588 obj->jmpslots_done = true;
589
590 return (0);
591 }
592
593 int
reloc_iresolve(Obj_Entry * obj,struct Struct_RtldLockState * lockstate)594 reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
595 {
596
597 /* XXX not implemented */
598 return (0);
599 }
600
601 int
reloc_gnu_ifunc(Obj_Entry * obj,int flags,struct Struct_RtldLockState * lockstate)602 reloc_gnu_ifunc(Obj_Entry *obj, int flags,
603 struct Struct_RtldLockState *lockstate)
604 {
605
606 /* XXX not implemented */
607 return (0);
608 }
609
610 Elf_Addr
reloc_jmpslot(Elf_Addr * where,Elf_Addr target,const Obj_Entry * defobj,const Obj_Entry * obj,const Elf_Rel * rel)611 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj,
612 const Obj_Entry *obj, const Elf_Rel *rel)
613 {
614
615 /* Do nothing */
616
617 return target;
618 }
619
620 void
allocate_initial_tls(Obj_Entry * objs)621 allocate_initial_tls(Obj_Entry *objs)
622 {
623 char *tls;
624
625 /*
626 * Fix the size of the static TLS block by using the maximum
627 * offset allocated so far and adding a bit for dynamic modules to
628 * use.
629 */
630 tls_static_space = tls_last_offset + tls_last_size + RTLD_STATIC_TLS_EXTRA;
631
632 tls = (char *) allocate_tls(objs, NULL, TLS_TCB_SIZE, 8);
633
634 sysarch(MIPS_SET_TLS, tls);
635 }
636
637 void *
__tls_get_addr(tls_index * ti)638 __tls_get_addr(tls_index* ti)
639 {
640 Elf_Addr** tls;
641 char *p;
642
643 sysarch(MIPS_GET_TLS, &tls);
644
645 p = tls_get_addr_common(tls, ti->ti_module, ti->ti_offset + TLS_DTP_OFFSET);
646
647 return (p);
648 }
649