1/* $NetBSD: ppc_reloc.c,v 1.48 2011/03/12 07:43:53 matt Exp $ */ 2 3/*- 4 * Copyright (C) 1998 Tsubai Masanari 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 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include <sys/cdefs.h> 32#ifndef lint 33__RCSID("$NetBSD: ppc_reloc.c,v 1.48 2011/03/12 07:43:53 matt Exp $"); 34#endif /* not lint */ 35 36#include <stdarg.h> 37#include <stdio.h> 38#include <stdlib.h> 39#include <string.h> 40#include <sys/types.h> 41#include <machine/cpu.h> 42 43#include "debug.h" 44#include "rtld.h" 45 46void _rtld_powerpc_pltcall(Elf_Word); 47void _rtld_powerpc_pltresolve(Elf_Word, Elf_Word); 48 49#define ha(x) ((((u_int32_t)(x) & 0x8000) ? \ 50 ((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16) 51#define l(x) ((u_int32_t)(x) & 0xffff) 52 53void _rtld_bind_bssplt_start(void); 54void _rtld_bind_secureplt_start(void); 55void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 56caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 57static int _rtld_relocate_plt_object(const Obj_Entry *, 58 const Elf_Rela *, int, Elf_Addr *); 59 60/* 61 * The PPC PLT format consists of three sections: 62 * (1) The "pltcall" and "pltresolve" glue code. This is always 18 words. 63 * (2) The code part of the PLT entries. There are 2 words per entry for 64 * up to 8192 entries, then 4 words per entry for any additional entries. 65 * (3) The data part of the PLT entries, comprising a jump table. 66 * This section is half the size of the second section (ie. 1 or 2 words 67 * per entry). 68 */ 69 70/* 71 * Setup the plt glue routines (for bss-plt). 72 */ 73#define PLTCALL_SIZE 20 74#define PLTRESOLVE_SIZE 24 75 76void 77_rtld_setup_pltgot(const Obj_Entry *obj) 78{ 79 /* 80 * Secure-PLT is much more sane. 81 */ 82 if (obj->gotptr != NULL) { 83 obj->gotptr[1] = (Elf_Addr) _rtld_bind_secureplt_start; 84 obj->gotptr[2] = (Elf_Addr) obj; 85 dbg(("obj %s secure-plt gotptr=%p start=%p obj=%p", 86 obj->path, obj->gotptr, 87 (void *) obj->gotptr[1], (void *) obj->gotptr[2])); 88 } else { 89 Elf_Word *pltcall, *pltresolve; 90 Elf_Word *jmptab; 91 int N = obj->pltrelalim - obj->pltrela; 92 93 /* Entries beyond 8192 take twice as much space. */ 94 if (N > 8192) 95 N += N-8192; 96 97 dbg(("obj %s bss-plt pltgot=%p jmptab=%u start=%p obj=%p", 98 obj->path, obj->pltgot, 18 + N * 2, 99 _rtld_bind_bssplt_start, obj)); 100 101 pltcall = obj->pltgot; 102 jmptab = pltcall + 18 + N * 2; 103 104 memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE); 105 pltcall[1] |= ha(jmptab); 106 pltcall[2] |= l(jmptab); 107 108 pltresolve = obj->pltgot + 8; 109 110 memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE); 111 pltresolve[0] |= ha(_rtld_bind_bssplt_start); 112 pltresolve[1] |= l(_rtld_bind_bssplt_start); 113 pltresolve[3] |= ha(obj); 114 pltresolve[4] |= l(obj); 115 116 /* 117 * Invalidate the icache for only the code part of the PLT 118 * (and not the jump table at the end). 119 */ 120 __syncicache(pltcall, (char *)jmptab - (char *)pltcall); 121 } 122} 123 124void 125_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 126{ 127 const Elf_Rela *rela = 0, *relalim; 128 Elf_Addr relasz = 0; 129 Elf_Addr *where; 130 131 for (; dynp->d_tag != DT_NULL; dynp++) { 132 switch (dynp->d_tag) { 133 case DT_RELA: 134 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 135 break; 136 case DT_RELASZ: 137 relasz = dynp->d_un.d_val; 138 break; 139 } 140 } 141 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 142 for (; rela < relalim; rela++) { 143 where = (Elf_Addr *)(relocbase + rela->r_offset); 144 *where = (Elf_Addr)(relocbase + rela->r_addend); 145 } 146} 147 148int 149_rtld_relocate_nonplt_objects(Obj_Entry *obj) 150{ 151 const Elf_Rela *rela; 152 153 for (rela = obj->rela; rela < obj->relalim; rela++) { 154 Elf_Addr *where; 155 const Elf_Sym *def; 156 const Obj_Entry *defobj; 157 Elf_Addr tmp; 158 unsigned long symnum; 159 160 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 161 symnum = ELF_R_SYM(rela->r_info); 162 163 switch (ELF_R_TYPE(rela->r_info)) { 164#if 1 /* XXX Should not be necessary. */ 165 case R_TYPE(JMP_SLOT): 166#endif 167 case R_TYPE(NONE): 168 break; 169 170 case R_TYPE(32): /* word32 S + A */ 171 case R_TYPE(GLOB_DAT): /* word32 S + A */ 172 def = _rtld_find_symdef(symnum, obj, &defobj, false); 173 if (def == NULL) 174 return -1; 175 176 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 177 rela->r_addend); 178 if (*where != tmp) 179 *where = tmp; 180 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 181 obj->strtab + obj->symtab[symnum].st_name, 182 obj->path, (void *)*where, defobj->path)); 183 break; 184 185 case R_TYPE(RELATIVE): /* word32 B + A */ 186 *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 187 rdbg(("RELATIVE in %s --> %p", obj->path, 188 (void *)*where)); 189 break; 190 191 case R_TYPE(COPY): 192 /* 193 * These are deferred until all other relocations have 194 * been done. All we do here is make sure that the 195 * COPY relocation is not in a shared library. They 196 * are allowed only in executable files. 197 */ 198 if (obj->isdynamic) { 199 _rtld_error( 200 "%s: Unexpected R_COPY relocation in shared library", 201 obj->path); 202 return -1; 203 } 204 rdbg(("COPY (avoid in main)")); 205 break; 206 207 case R_TYPE(DTPMOD32): 208 def = _rtld_find_symdef(symnum, obj, &defobj, false); 209 if (def == NULL) 210 return -1; 211 212 *where = (Elf_Addr)defobj->tlsindex; 213 rdbg(("DTPMOD32 %s in %s --> %p in %s", 214 obj->strtab + obj->symtab[symnum].st_name, 215 obj->path, (void *)*where, defobj->path)); 216 break; 217 218 case R_TYPE(DTPREL32): 219 def = _rtld_find_symdef(symnum, obj, &defobj, false); 220 if (def == NULL) 221 return -1; 222 223 if (!defobj->tls_done && _rtld_tls_offset_allocate(obj)) 224 return -1; 225 226 *where = (Elf_Addr)(def->st_value + rela->r_addend 227 - TLS_DTV_OFFSET); 228 rdbg(("DTPREL32 %s in %s --> %p in %s", 229 obj->strtab + obj->symtab[symnum].st_name, 230 obj->path, (void *)*where, defobj->path)); 231 break; 232 233 case R_TYPE(TPREL32): 234 def = _rtld_find_symdef(symnum, obj, &defobj, false); 235 if (def == NULL) 236 return -1; 237 238 if (!defobj->tls_done && _rtld_tls_offset_allocate(obj)) 239 return -1; 240 241 *where = (Elf_Addr)(def->st_value + rela->r_addend 242 + defobj->tlsoffset - TLS_TP_OFFSET); 243 rdbg(("TPREL32 %s in %s --> %p in %s", 244 obj->strtab + obj->symtab[symnum].st_name, 245 obj->path, (void *)*where, defobj->path)); 246 break; 247 248 default: 249 rdbg(("sym = %lu, type = %lu, offset = %p, " 250 "addend = %p, contents = %p, symbol = %s", 251 symnum, (u_long)ELF_R_TYPE(rela->r_info), 252 (void *)rela->r_offset, (void *)rela->r_addend, 253 (void *)*where, 254 obj->strtab + obj->symtab[symnum].st_name)); 255 _rtld_error("%s: Unsupported relocation type %ld " 256 "in non-PLT relocations", 257 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 258 return -1; 259 } 260 } 261 return 0; 262} 263 264int 265_rtld_relocate_plt_lazy(const Obj_Entry *obj) 266{ 267 Elf_Addr * const pltresolve = obj->pltgot + 8; 268 const Elf_Rela *rela; 269 int reloff; 270 271 for (rela = obj->pltrela, reloff = 0; 272 rela < obj->pltrelalim; 273 rela++, reloff++) { 274 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 275 276 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 277 278 if (obj->gotptr != NULL) { 279 /* 280 * For now, simply treat then as relative. 281 */ 282 *where += (Elf_Addr)obj->relocbase; 283 } else { 284 int distance; 285 286 if (reloff < 32768) { 287 /* li r11,reloff */ 288 *where++ = 0x39600000 | reloff; 289 } else { 290 /* lis r11,ha(reloff) */ 291 /* addi r11,l(reloff) */ 292 *where++ = 0x3d600000 | ha(reloff); 293 *where++ = 0x396b0000 | l(reloff); 294 } 295 /* b pltresolve */ 296 distance = (Elf_Addr)pltresolve - (Elf_Addr)where; 297 *where++ = 0x48000000 | (distance & 0x03fffffc); 298 299 /* 300 * Icache invalidation is not done for each entry here 301 * because we sync the entire code part of the PLT once 302 * in _rtld_setup_pltgot() after all the entries have been 303 * initialized. 304 */ 305 /* __syncicache(where - 3, 12); */ 306 } 307 } 308 309 return 0; 310} 311 312static int 313_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, int reloff, Elf_Addr *tp) 314{ 315 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 316 Elf_Addr value; 317 const Elf_Sym *def; 318 const Obj_Entry *defobj; 319 int distance; 320 unsigned long info = rela->r_info; 321 322 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 323 324 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 325 if (__predict_false(def == NULL)) 326 return -1; 327 if (__predict_false(def == &_rtld_sym_zero)) 328 return 0; 329 330 value = (Elf_Addr)(defobj->relocbase + def->st_value); 331 distance = value - (Elf_Addr)where; 332 rdbg(("bind now/fixup in %s --> new=%p", 333 defobj->strtab + def->st_name, (void *)value)); 334 335 if (obj->gotptr != NULL) { 336 /* 337 * For Secure-PLT we simply replace the entry in GOT with the address 338 * of the routine. 339 */ 340 assert(where >= (Elf_Word *)obj->pltgot); 341 assert(where < (Elf_Word *)obj->pltgot + (obj->pltrelalim - obj->pltrela)); 342 *where = value; 343 } else if (abs(distance) < 32*1024*1024) { /* inside 32MB? */ 344 /* b value # branch directly */ 345 *where = 0x48000000 | (distance & 0x03fffffc); 346 __syncicache(where, 4); 347 } else { 348 Elf_Addr *pltcall, *jmptab; 349 int N = obj->pltrelalim - obj->pltrela; 350 351 /* Entries beyond 8192 take twice as much space. */ 352 if (N > 8192) 353 N += N-8192; 354 355 pltcall = obj->pltgot; 356 jmptab = pltcall + 18 + N * 2; 357 358 jmptab[reloff] = value; 359 360 if (reloff < 32768) { 361 /* li r11,reloff */ 362 *where++ = 0x39600000 | reloff; 363 } else { 364#ifdef notyet 365 /* lis r11,ha(value) */ 366 /* addi r11,l(value) */ 367 /* mtctr r11 */ 368 /* bctr */ 369 *where++ = 0x3d600000 | ha(value); 370 *where++ = 0x396b0000 | l(value); 371 *where++ = 0x7d6903a6; 372 *where++ = 0x4e800420; 373#else 374 /* lis r11,ha(reloff) */ 375 /* addi r11,l(reloff) */ 376 *where++ = 0x3d600000 | ha(reloff); 377 *where++ = 0x396b0000 | l(reloff); 378#endif 379 } 380 /* b pltcall */ 381 distance = (Elf_Addr)pltcall - (Elf_Addr)where; 382 *where++ = 0x48000000 | (distance & 0x03fffffc); 383 __syncicache(where - 3, 12); 384 } 385 386 if (tp) 387 *tp = value; 388 return 0; 389} 390 391caddr_t 392_rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 393{ 394 const Elf_Rela *rela = obj->pltrela + reloff; 395 Elf_Addr new_value; 396 int err; 397 398 new_value = 0; /* XXX gcc */ 399 400 _rtld_shared_enter(); 401 err = _rtld_relocate_plt_object(obj, rela, reloff, &new_value); 402 if (err) 403 _rtld_die(); 404 _rtld_shared_exit(); 405 406 return (caddr_t)new_value; 407} 408 409int 410_rtld_relocate_plt_objects(const Obj_Entry *obj) 411{ 412 const Elf_Rela *rela; 413 int reloff; 414 415 for (rela = obj->pltrela, reloff = 0; rela < obj->pltrelalim; rela++, reloff++) { 416 if (_rtld_relocate_plt_object(obj, rela, reloff, NULL) < 0) 417 return -1; 418 } 419 return 0; 420} 421