1 /* $NetBSD: mips_reloc.c,v 1.58 2010/01/14 11:57:06 skrll Exp $ */
4 * Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
5 * Portions copyright 2002 Charles M. Hannum <root@ihack.net>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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.
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/types.h>
36 #include <sys/endian.h>
45 #define GOT1_MASK 0x8000000000000000UL
47 #define GOT1_MASK 0x80000000UL
51 init_pltgot(Obj_Entry *obj)
53 if (obj->pltgot != NULL) {
54 obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
55 if (obj->pltgot[1] & 0x80000000)
56 obj->pltgot[1] = (Elf_Addr) obj | GOT1_MASK;
61 do_copy_relocations(Obj_Entry *dstobj)
67 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
70 * It is possible for the compiler to emit relocations for unaligned data.
71 * We handle this situation with these inlines.
75 * ELF64 MIPS encodes the relocs uniquely. The first 32-bits of info contain
76 * the symbol index. The top 32-bits contain three relocation types encoded
77 * in big-endian integer with first relocation in LSB. This means for little
78 * endian we have to byte swap that integer (r_type).
80 #define Elf_Sxword Elf64_Sxword
81 #define ELF_R_NXTTYPE_64_P(r_type) ((((r_type) >> 8) & 0xff) == R_TYPE(64))
82 #if BYTE_ORDER == LITTLE_ENDIAN
85 #define ELF_R_SYM(r_info) ((r_info) & 0xffffffff)
86 #define ELF_R_TYPE(r_info) bswap32(((r_info) >> 32))
89 #define ELF_R_NXTTYPE_64_P(r_type) (0)
90 #define Elf_Sxword Elf32_Sword
93 static __inline Elf_Sxword
94 load_ptr(void *where, size_t len)
98 if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
100 if (len == sizeof(Elf_Sxword))
101 return *(Elf_Sxword *)where;
103 return *(Elf_Sword *)where;
107 #if BYTE_ORDER == LITTLE_ENDIAN
108 (void)memcpy(&val, where, len);
110 #if BYTE_ORDER == BIG_ENDIAN
111 (void)memcpy((uint8_t *)((&val)+1) - len, where, len);
113 return (len == sizeof(Elf_Sxword)) ? val : (Elf_Sword)val;
117 store_ptr(void *where, Elf_Sxword val, size_t len)
119 if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
121 if (len == sizeof(Elf_Sxword)) {
122 *(Elf_Sxword *)where = val;
126 *(Elf_Sword *)where = val;
129 #if BYTE_ORDER == LITTLE_ENDIAN
130 (void)memcpy(where, &val, len);
132 #if BYTE_ORDER == BIG_ENDIAN
133 (void)memcpy(where, (const uint8_t *)((&val)+1) - len, len);
138 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
140 const Elf_Rel *rel = 0, *rellim;
142 const Elf_Sym *symtab = NULL, *sym;
144 Elf_Addr *got = NULL;
145 Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0;
148 for (; dynp->d_tag != DT_NULL; dynp++) {
149 switch (dynp->d_tag) {
151 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr);
154 relsz = dynp->d_un.d_val;
157 symtab = (const Elf_Sym *)(relocbase + dynp->d_un.d_ptr);
160 got = (Elf_Addr *)(relocbase + dynp->d_un.d_ptr);
162 case DT_MIPS_LOCAL_GOTNO:
163 local_gotno = dynp->d_un.d_val;
165 case DT_MIPS_SYMTABNO:
166 symtabno = dynp->d_un.d_val;
169 gotsym = dynp->d_un.d_val;
174 i = (got[1] & GOT1_MASK) ? 2 : 1;
175 /* Relocate the local GOT entries */
177 for (; i < local_gotno; i++) {
181 sym = symtab + gotsym;
182 /* Now do the global GOT entries */
183 for (i = gotsym; i < symtabno; i++) {
184 *got = sym->st_value + relocbase;
189 rellim = (const Elf_Rel *)((caddr_t)rel + relsz);
190 for (; rel < rellim; rel++) {
191 Elf_Word r_symndx, r_type;
193 where = (void *)(relocbase + rel->r_offset);
195 r_symndx = ELF_R_SYM(rel->r_info);
196 r_type = ELF_R_TYPE(rel->r_info);
198 switch (r_type & 0xff) {
199 case R_TYPE(REL32): {
201 ELF_R_NXTTYPE_64_P(r_type)
204 Elf_Sxword old = load_ptr(where, rlen);
205 Elf_Sxword val = old;
207 assert(r_type == R_TYPE(REL32)
208 || r_type == (R_TYPE(REL32)|(R_TYPE(64) << 8)));
210 assert(r_symndx < gotsym);
211 sym = symtab + r_symndx;
212 assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL);
214 store_ptr(where, val, sizeof(Elf_Sword));
215 dbg("REL32/L(%p) %p -> %p in <self>",
216 where, (void *)old, (void *)val);
217 store_ptr(where, val, rlen);
221 case R_TYPE(GPREL32):
234 _mips_rtld_bind(Obj_Entry *obj, Elf_Size reloff)
236 Elf_Addr *got = obj->pltgot;
238 const Obj_Entry *defobj;
241 def = find_symdef(reloff, obj, &defobj, SYMLOOK_IN_PLT, NULL);
243 _rtld_error("bind failed no symbol");
245 target = (Elf_Addr)(defobj->relocbase + def->st_value);
246 dbg("bind now/fixup at %s sym # %d in %s --> was=%p new=%p",
248 reloff, defobj->strtab + def->st_name,
249 (void *)got[obj->local_gotno + reloff - obj->gotsym],
251 got[obj->local_gotno + reloff - obj->gotsym] = target;
252 return (Elf_Addr)target;
256 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
259 const Elf_Rel *rellim;
260 Elf_Addr *got = obj->pltgot;
261 const Elf_Sym *sym, *def;
262 const Obj_Entry *defobj;
264 #ifdef SUPPORT_OLD_BROKEN_LD
268 /* The relocation for the dynamic loader has already been done. */
272 #ifdef SUPPORT_OLD_BROKEN_LD
275 for (i = 1; i < 12; i++)
276 if (sym[i].st_info == ELF_ST_INFO(STB_LOCAL, STT_NOTYPE))
278 dbg("%s: broken=%d", obj->path, broken);
281 i = (got[1] & GOT1_MASK) ? 2 : 1;
283 /* Relocate the local GOT entries */
285 dbg("got:%p for %d entries adding %x",
286 got, obj->local_gotno, (uint32_t)obj->relocbase);
287 for (; i < obj->local_gotno; i++) {
288 *got += (Elf_Addr)obj->relocbase;
291 sym = obj->symtab + obj->gotsym;
293 dbg("got:%p for %d entries",
295 /* Now do the global GOT entries */
296 for (i = obj->gotsym; i < obj->symtabno; i++) {
297 dbg(" doing got %d sym %p (%s, %lx)", i - obj->gotsym, sym,
298 sym->st_name + obj->strtab, (u_long) *got);
300 #ifdef SUPPORT_OLD_BROKEN_LD
301 if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
302 broken && sym->st_shndx == SHN_UNDEF) {
304 * XXX DANGER WILL ROBINSON!
305 * You might think this is stupid, as it intentionally
306 * defeats lazy binding -- and you'd be right.
307 * Unfortunately, for lazy binding to work right, we
308 * need to a way to force the GOT slots used for
309 * function pointers to be resolved immediately. This
310 * is supposed to be done automatically by the linker,
311 * by not outputting a PLT slot and setting st_value
312 * to 0 if there are non-PLT references, but older
313 * versions of GNU ld do not do this.
315 def = find_symdef(i, obj, &defobj, false, NULL);
318 *got = def->st_value + (Elf_Addr)defobj->relocbase;
321 if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
322 sym->st_value != 0 && sym->st_shndx == SHN_UNDEF) {
324 * If there are non-PLT references to the function,
325 * st_value should be 0, forcing us to resolve the
326 * address immediately.
328 * XXX DANGER WILL ROBINSON!
329 * The linker is not outputting PLT slots for calls to
330 * functions that are defined in the same shared
331 * library. This is a bug, because it can screw up
332 * link ordering rules if the symbol is defined in
333 * more than one module. For now, if there is a
334 * definition, we fail the test above and force a full
335 * symbol lookup. This means that all intra-module
336 * calls are bound immediately. - mycroft, 2003/09/24
338 *got = sym->st_value + (Elf_Addr)obj->relocbase;
339 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
340 dbg("Warning2, i:%d maps to relocbase address:%x",
341 i, (uint32_t)obj->relocbase);
344 } else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) {
345 /* Symbols with index SHN_ABS are not relocated. */
346 if (sym->st_shndx != SHN_ABS) {
347 *got = sym->st_value +
348 (Elf_Addr)obj->relocbase;
349 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
350 dbg("Warning3, i:%d maps to relocbase address:%x",
351 i, (uint32_t)obj->relocbase);
355 /* TODO: add cache here */
356 def = find_symdef(i, obj, &defobj, false, NULL);
358 dbg("Warning4, cant find symbole %d", i);
361 *got = def->st_value + (Elf_Addr)defobj->relocbase;
362 if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
363 dbg("Warning4, i:%d maps to relocbase address:%x",
364 i, (uint32_t)obj->relocbase);
365 dbg("via first obj symbol %s",
366 obj->strtab + obj->symtab[i].st_name);
367 dbg("found in obj %p:%s",
368 defobj, defobj->path);
372 dbg(" --> now %lx", (u_long) *got);
378 rellim = (const Elf_Rel *)((caddr_t)obj->rel + obj->relsize);
379 for (rel = obj->rel; rel < rellim; rel++) {
380 Elf_Word r_symndx, r_type;
383 where = obj->relocbase + rel->r_offset;
384 r_symndx = ELF_R_SYM(rel->r_info);
385 r_type = ELF_R_TYPE(rel->r_info);
387 switch (r_type & 0xff) {
391 case R_TYPE(REL32): {
392 /* 32-bit PC-relative reference */
394 ELF_R_NXTTYPE_64_P(r_type)
397 Elf_Sxword old = load_ptr(where, rlen);
398 Elf_Sxword val = old;
400 def = obj->symtab + r_symndx;
402 if (r_symndx >= obj->gotsym) {
403 val += got[obj->local_gotno + r_symndx - obj->gotsym];
404 dbg("REL32/G(%p) %p --> %p (%s) in %s",
405 where, (void *)old, (void *)val,
406 obj->strtab + def->st_name,
410 * XXX: ABI DIFFERENCE!
412 * Old NetBSD binutils would generate shared
413 * libs with section-relative relocations being
414 * already adjusted for the start address of
417 * New binutils, OTOH, generate shared libs
418 * with the same relocations being based at
419 * zero, so we need to add in the start address
426 ELF_ST_INFO(STB_LOCAL, STT_SECTION)
427 #ifdef SUPPORT_OLD_BROKEN_LD
431 val += (Elf_Addr)def->st_value;
433 val += (Elf_Addr)obj->relocbase;
435 dbg("REL32/L(%p) %p -> %p (%s) in %s",
436 where, (void *)old, (void *)val,
437 obj->strtab + def->st_name, obj->path);
439 store_ptr(where, val, rlen);
444 dbg("sym = %lu, type = %lu, offset = %p, "
445 "contents = %p, symbol = %s",
446 (u_long)r_symndx, (u_long)ELF_R_TYPE(rel->r_info),
447 (void *)rel->r_offset,
448 (void *)load_ptr(where, sizeof(Elf_Sword)),
449 obj->strtab + obj->symtab[r_symndx].st_name);
450 _rtld_error("%s: Unsupported relocation type %ld "
451 "in non-PLT relocations",
452 obj->path, (u_long) ELF_R_TYPE(rel->r_info));
461 * Process the PLT relocations.
464 reloc_plt(Obj_Entry *obj)
467 const Elf_Rel *rellim;
470 dbg("reloc_plt obj:%p pltrel:%p sz:%d", obj, obj->pltrel, (int)obj->pltrelsize);
471 dbg("gottable %p num syms:%d", obj->pltgot, obj->symtabno );
472 dbg("*****************************************************");
473 rellim = (const Elf_Rel *)((char *)obj->pltrel +
475 for (rel = obj->pltrel; rel < rellim; rel++) {
477 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
478 *where += (Elf_Addr )obj->relocbase;
482 /* PLT fixups were done above in the GOT relocation. */
487 * LD_BIND_NOW was set - force relocation for all jump slots
490 reloc_jmpslots(Obj_Entry *obj)
493 obj->jmpslots_done = true;
499 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj,
500 const Obj_Entry *obj, const Elf_Rel *rel)
509 allocate_initial_tls(Obj_Entry *objs)
515 __tls_get_addr(tls_index* ti)