1/* $NetBSD: mdreloc.c,v 1.52 2011/03/30 08:37:52 martin Exp $ */ 2 3/*- 4 * Copyright (c) 2000 Eduardo Horvath. 5 * Copyright (c) 1999, 2002 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Paul Kranenburg and by Charles M. Hannum. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33#include <sys/cdefs.h> 34#ifndef lint 35__RCSID("$NetBSD: mdreloc.c,v 1.52 2011/03/30 08:37:52 martin Exp $"); 36#endif /* not lint */ 37 38#include <errno.h> 39#include <stdio.h> 40#include <stdlib.h> 41#include <string.h> 42#include <unistd.h> 43 44#include "rtldenv.h" 45#include "debug.h" 46#include "rtld.h" 47 48/* 49 * The following table holds for each relocation type: 50 * - the width in bits of the memory location the relocation 51 * applies to (not currently used) 52 * - the number of bits the relocation value must be shifted to the 53 * right (i.e. discard least significant bits) to fit into 54 * the appropriate field in the instruction word. 55 * - flags indicating whether 56 * * the relocation involves a symbol 57 * * the relocation is relative to the current position 58 * * the relocation is for a GOT entry 59 * * the relocation is relative to the load address 60 * 61 */ 62#define _RF_S 0x80000000 /* Resolve symbol */ 63#define _RF_A 0x40000000 /* Use addend */ 64#define _RF_P 0x20000000 /* Location relative */ 65#define _RF_G 0x10000000 /* GOT offset */ 66#define _RF_B 0x08000000 /* Load address relative */ 67#define _RF_U 0x04000000 /* Unaligned */ 68#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ 69#define _RF_RS(s) ( (s) & 0xff) /* right shift */ 70static const int reloc_target_flags[R_TYPE(TLS_TPOFF64)+1] = { 71 0, /* NONE */ 72 _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ 73 _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ 74 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ 75 _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ 76 _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ 77 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ 78 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ 79 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ 80 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ 81 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ 82 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ 83 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ 84 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ 85 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ 86 _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ 87 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ 88 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ 89 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ 90 _RF_SZ(32) | _RF_RS(0), /* COPY */ 91 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* GLOB_DAT */ 92 _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ 93 _RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */ 94 _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ 95 96 _RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */ 97 _RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */ 98 _RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ 99 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ 100 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */ 101 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */ 102 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */ 103 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */ 104 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */ 105 _RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ 106 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */ 107 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */ 108 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */ 109 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */ 110 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */ 111 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */ 112 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */ 113 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */ 114 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ 115 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */ 116 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */ 117 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */ 118 _RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */ 119 _RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */ 120 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */ 121 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */ 122 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */ 123 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */ 124 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */ 125 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */ 126 _RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */ 127 _RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */ 128/* TLS relocs not represented here! */ 129}; 130 131#ifdef RTLD_DEBUG_RELOC 132static const char *reloc_names[] = { 133 "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", 134 "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", 135 "22", "13", "LO10", "GOT10", "GOT13", 136 "GOT22", "PC10", "PC22", "WPLT30", "COPY", 137 "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", "PLT32", 138 "HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32", 139 "10", "11", "64", "OLO10", "HH22", 140 "HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22", 141 "WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6", 142 "DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44", 143 "L44", "REGISTER", "UA64", "UA16", 144 "TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL", 145 "TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL", 146 "TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22", 147 "TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22", 148 "TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32", 149 "TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64", 150}; 151#endif 152 153#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) 154#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) 155#define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) 156#define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) 157#define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) 158#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) 159#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) 160#define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22)) 161 162static const long reloc_target_bitmask[] = { 163#define _BM(x) (~(-(1ULL << (x)))) 164 0, /* NONE */ 165 _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ 166 _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ 167 _BM(30), _BM(22), /* WDISP30, WDISP22 */ 168 _BM(22), _BM(22), /* HI22, _22 */ 169 _BM(13), _BM(10), /* RELOC_13, _LO10 */ 170 _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ 171 _BM(10), _BM(22), /* _PC10, _PC22 */ 172 _BM(30), 0, /* _WPLT30, _COPY */ 173 _BM(32), _BM(32), _BM(32), /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ 174 _BM(32), _BM(32), /* _UA32, PLT32 */ 175 _BM(22), _BM(10), /* _HIPLT22, LOPLT10 */ 176 _BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */ 177 _BM(10), _BM(11), -1, /* _10, _11, _64 */ 178 _BM(10), _BM(22), /* _OLO10, _HH22 */ 179 _BM(10), _BM(22), /* _HM10, _LM22 */ 180 _BM(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */ 181 _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ 182 -1, /* GLOB_JMP */ 183 _BM(7), _BM(5), _BM(6) /* _7, _5, _6 */ 184 -1, -1, /* DISP64, PLT64 */ 185 _BM(22), _BM(13), /* HIX22, LOX10 */ 186 _BM(22), _BM(10), _BM(13), /* H44, M44, L44 */ 187 -1, -1, _BM(16), /* REGISTER, UA64, UA16 */ 188#undef _BM 189}; 190#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) 191 192/* 193 * Instruction templates: 194 */ 195#define BAA 0x10400000 /* ba,a %xcc, 0 */ 196#define SETHI 0x03000000 /* sethi %hi(0), %g1 */ 197#define JMP 0x81c06000 /* jmpl %g1+%lo(0), %g0 */ 198#define NOP 0x01000000 /* sethi %hi(0), %g0 */ 199#define OR 0x82806000 /* or %g1, 0, %g1 */ 200#define XOR 0x82c06000 /* xor %g1, 0, %g1 */ 201#define MOV71 0x8283a000 /* or %o7, 0, %g1 */ 202#define MOV17 0x9c806000 /* or %g1, 0, %o7 */ 203#define CALL 0x40000000 /* call 0 */ 204#define SLLX 0x8b407000 /* sllx %g1, 0, %g1 */ 205#define SETHIG5 0x0b000000 /* sethi %hi(0), %g5 */ 206#define ORG5 0x82804005 /* or %g1, %g5, %g1 */ 207 208 209/* %hi(v)/%lo(v) with variable shift */ 210#define HIVAL(v, s) (((v) >> (s)) & 0x003fffff) 211#define LOVAL(v, s) (((v) >> (s)) & 0x000003ff) 212 213void _rtld_bind_start_0(long, long); 214void _rtld_bind_start_1(long, long); 215void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 216caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 217 218/* 219 * Install rtld function call into this PLT slot. 220 */ 221#define SAVE 0x9de3bf50 /* i.e. `save %sp,-176,%sp' */ 222#define SETHI_l0 0x21000000 223#define SETHI_l1 0x23000000 224#define OR_l0_l0 0xa0142000 225#define SLLX_l0_32_l0 0xa12c3020 226#define OR_l0_l1_l0 0xa0140011 227#define JMPL_l0_o0 0x91c42000 228#define MOV_g1_o1 0x92100001 229 230void _rtld_install_plt(Elf_Word *, Elf_Addr); 231static inline int _rtld_relocate_plt_object(const Obj_Entry *, 232 const Elf_Rela *, Elf_Addr *); 233 234void 235_rtld_install_plt(Elf_Word *pltgot, Elf_Addr proc) 236{ 237 pltgot[0] = SAVE; 238 pltgot[1] = SETHI_l0 | HIVAL(proc, 42); 239 pltgot[2] = SETHI_l1 | HIVAL(proc, 10); 240 pltgot[3] = OR_l0_l0 | LOVAL(proc, 32); 241 pltgot[4] = SLLX_l0_32_l0; 242 pltgot[5] = OR_l0_l1_l0; 243 pltgot[6] = JMPL_l0_o0 | LOVAL(proc, 0); 244 pltgot[7] = MOV_g1_o1; 245} 246 247void 248_rtld_setup_pltgot(const Obj_Entry *obj) 249{ 250 /* 251 * On sparc64 we got troubles. 252 * 253 * Instructions are 4 bytes long. 254 * Elf[64]_Addr is 8 bytes long, so are our pltglot[] 255 * array entries. 256 * Each PLT entry jumps to PLT0 to enter the dynamic 257 * linker. 258 * Loading an arbitrary 64-bit pointer takes 6 259 * instructions and 2 registers. 260 * 261 * Somehow we need to issue a save to get a new stack 262 * frame, load the address of the dynamic linker, and 263 * jump there, in 8 instructions or less. 264 * 265 * Oh, we need to fill out both PLT0 and PLT1. 266 */ 267 { 268 Elf_Word *entry = (Elf_Word *)obj->pltgot; 269 270 /* Install in entries 0 and 1 */ 271 _rtld_install_plt(&entry[0], (Elf_Addr) &_rtld_bind_start_0); 272 _rtld_install_plt(&entry[8], (Elf_Addr) &_rtld_bind_start_1); 273 274 /* 275 * Install the object reference in first slot 276 * of entry 2. 277 */ 278 obj->pltgot[8] = (Elf_Addr) obj; 279 } 280} 281 282void 283_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 284{ 285 const Elf_Rela *rela = 0, *relalim; 286 Elf_Addr relasz = 0; 287 Elf_Addr *where; 288 289 for (; dynp->d_tag != DT_NULL; dynp++) { 290 switch (dynp->d_tag) { 291 case DT_RELA: 292 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 293 break; 294 case DT_RELASZ: 295 relasz = dynp->d_un.d_val; 296 break; 297 } 298 } 299 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 300 for (; rela < relalim; rela++) { 301 where = (Elf_Addr *)(relocbase + rela->r_offset); 302 *where = (Elf_Addr)(relocbase + rela->r_addend); 303 } 304} 305 306int 307_rtld_relocate_nonplt_objects(Obj_Entry *obj) 308{ 309 const Elf_Rela *rela; 310 const Elf_Sym *def = NULL; 311 const Obj_Entry *defobj = NULL; 312 313 for (rela = obj->rela; rela < obj->relalim; rela++) { 314 Elf_Addr *where; 315 Elf_Word type; 316 Elf_Addr value = 0, mask; 317 unsigned long symnum; 318 319 where = (Elf_Addr *) (obj->relocbase + rela->r_offset); 320 symnum = ELF_R_SYM(rela->r_info); 321 322 type = ELF_R_TYPE(rela->r_info); 323 if (type == R_TYPE(NONE)) 324 continue; 325 326 /* OLO10 relocations have extra info */ 327 if ((type & 0x00ff) == R_SPARC_OLO10) 328 type = R_SPARC_OLO10; 329 330 /* We do JMP_SLOTs in _rtld_bind() below */ 331 if (type == R_TYPE(JMP_SLOT)) 332 continue; 333 334 /* COPY relocs are also handled elsewhere */ 335 if (type == R_TYPE(COPY)) 336 continue; 337 338 /* 339 * We use the fact that relocation types are an `enum' 340 * Note: R_SPARC_TLS_TPOFF64 is currently numerically largest. 341 */ 342 if (type > R_TYPE(TLS_TPOFF64)) { 343 dbg(("unknown relocation type %x at %p", type, rela)); 344 return -1; 345 } 346 347 value = rela->r_addend; 348 349 /* 350 * Handle TLS relocations here, they are different. 351 */ 352 if (RELOC_TLS(type)) { 353 switch (type) { 354 case R_TYPE(TLS_DTPMOD64): 355 def = _rtld_find_symdef(symnum, obj, 356 &defobj, false); 357 if (def == NULL) 358 return -1; 359 360 *where = (Elf64_Addr)defobj->tlsindex; 361 362 rdbg(("TLS_DTPMOD64 %s in %s --> %p", 363 obj->strtab + 364 obj->symtab[symnum].st_name, 365 obj->path, (void *)*where)); 366 367 break; 368 369 case R_TYPE(TLS_DTPOFF64): 370 def = _rtld_find_symdef(symnum, obj, 371 &defobj, false); 372 if (def == NULL) 373 return -1; 374 375 *where = (Elf64_Addr)(def->st_value 376 + rela->r_addend); 377 378 rdbg(("DTPOFF64 %s in %s --> %p", 379 obj->strtab + 380 obj->symtab[symnum].st_name, 381 obj->path, (void *)*where)); 382 383 break; 384 385 case R_TYPE(TLS_TPOFF64): 386 def = _rtld_find_symdef(symnum, obj, 387 &defobj, false); 388 if (def == NULL) 389 return -1; 390 391 if (!defobj->tls_done && 392 _rtld_tls_offset_allocate(obj)) 393 return -1; 394 395 *where = (Elf64_Addr)(def->st_value - 396 defobj->tlsoffset + 397 rela->r_addend); 398 399 rdbg(("TLS_TPOFF64 %s in %s --> %p", 400 obj->strtab + 401 obj->symtab[symnum].st_name, 402 obj->path, (void *)*where)); 403 404 break; 405 } 406 continue; 407 } 408 409 /* 410 * Handle relative relocs here, as an optimization. 411 */ 412 if (type == R_TYPE(RELATIVE)) { 413 *where = (Elf_Addr)(obj->relocbase + value); 414 rdbg(("RELATIVE in %s --> %p", obj->path, 415 (void *)*where)); 416 continue; 417 } 418 419 if (RELOC_RESOLVE_SYMBOL(type)) { 420 421 /* Find the symbol */ 422 def = _rtld_find_symdef(symnum, obj, &defobj, 423 false); 424 if (def == NULL) 425 return -1; 426 427 /* Add in the symbol's absolute address */ 428 value += (Elf_Addr)(defobj->relocbase + def->st_value); 429 } 430 431 if (type == R_SPARC_OLO10) { 432 value = (value & 0x3ff) 433 + (((Elf64_Xword)rela->r_info<<32)>>40); 434 } 435 436 if (RELOC_PC_RELATIVE(type)) { 437 value -= (Elf_Addr)where; 438 } 439 440 if (RELOC_BASE_RELATIVE(type)) { 441 /* 442 * Note that even though sparcs use `Elf_rela' 443 * exclusively we still need the implicit memory addend 444 * in relocations referring to GOT entries. 445 * Undoubtedly, someone f*cked this up in the distant 446 * past, and now we're stuck with it in the name of 447 * compatibility for all eternity.. 448 * 449 * In any case, the implicit and explicit should be 450 * mutually exclusive. We provide a check for that 451 * here. 452 */ 453#ifdef DIAGNOSTIC 454 if (value != 0 && *where != 0) { 455 xprintf("BASE_REL(%s): where=%p, *where 0x%lx, " 456 "addend=0x%lx, base %p\n", 457 obj->path, where, *where, 458 rela->r_addend, obj->relocbase); 459 } 460#endif 461 /* XXXX -- apparently we ignore the preexisting value */ 462 value += (Elf_Addr)(obj->relocbase); 463 } 464 465 mask = RELOC_VALUE_BITMASK(type); 466 value >>= RELOC_VALUE_RIGHTSHIFT(type); 467 value &= mask; 468 469 if (RELOC_UNALIGNED(type)) { 470 /* Handle unaligned relocations. */ 471 Elf_Addr tmp = 0; 472 char *ptr = (char *)where; 473 int i, size = RELOC_TARGET_SIZE(type)/8; 474 475 /* Read it in one byte at a time. */ 476 for (i=0; i<size; i++) 477 tmp = (tmp << 8) | ptr[i]; 478 479 tmp &= ~mask; 480 tmp |= value; 481 482 /* Write it back out. */ 483 for (i=0; i<size; i++) 484 ptr[i] = ((tmp >> (8*i)) & 0xff); 485#ifdef RTLD_DEBUG_RELOC 486 value = (Elf_Addr)tmp; 487#endif 488 489 } else if (RELOC_TARGET_SIZE(type) > 32) { 490 *where &= ~mask; 491 *where |= value; 492#ifdef RTLD_DEBUG_RELOC 493 value = (Elf_Addr)*where; 494#endif 495 } else { 496 Elf32_Addr *where32 = (Elf32_Addr *)where; 497 498 *where32 &= ~mask; 499 *where32 |= value; 500#ifdef RTLD_DEBUG_RELOC 501 value = (Elf_Addr)*where32; 502#endif 503 } 504 505#ifdef RTLD_DEBUG_RELOC 506 if (RELOC_RESOLVE_SYMBOL(type)) { 507 rdbg(("%s %s in %s --> %p in %s", reloc_names[type], 508 obj->strtab + obj->symtab[symnum].st_name, 509 obj->path, (void *)value, defobj->path)); 510 } else { 511 rdbg(("%s in %s --> %p", reloc_names[type], 512 obj->path, (void *)value)); 513 } 514#endif 515 } 516 return (0); 517} 518 519int 520_rtld_relocate_plt_lazy(const Obj_Entry *obj) 521{ 522 return (0); 523} 524 525caddr_t 526_rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 527{ 528 const Elf_Rela *rela = obj->pltrela + reloff; 529 Elf_Addr result; 530 int err; 531 532 result = 0; /* XXX gcc */ 533 534 if (ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_SLOT)) { 535 /* 536 * XXXX 537 * 538 * The first four PLT entries are reserved. There is some 539 * disagreement whether they should have associated relocation 540 * entries. Both the SPARC 32-bit and 64-bit ELF 541 * specifications say that they should have relocation entries, 542 * but the 32-bit SPARC binutils do not generate them, and now 543 * the 64-bit SPARC binutils have stopped generating them too. 544 * 545 * So, to provide binary compatibility, we will check the first 546 * entry, if it is reserved it should not be of the type 547 * JMP_SLOT. If it is JMP_SLOT, then the 4 reserved entries 548 * were not generated and our index is 4 entries too far. 549 */ 550 rela -= 4; 551 } 552 553 _rtld_shared_enter(); 554 err = _rtld_relocate_plt_object(obj, rela, &result); 555 if (err) 556 _rtld_die(); 557 _rtld_shared_exit(); 558 559 return (caddr_t)result; 560} 561 562int 563_rtld_relocate_plt_objects(const Obj_Entry *obj) 564{ 565 const Elf_Rela *rela; 566 567 rela = obj->pltrela; 568 569 /* 570 * Check for first four reserved entries - and skip them. 571 * See above for details. 572 */ 573 if (ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_SLOT)) 574 rela += 4; 575 576 for (; rela < obj->pltrelalim; rela++) 577 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 578 return -1; 579 580 return 0; 581} 582 583/* 584 * New inline function that is called by _rtld_relocate_plt_object and 585 * _rtld_bind 586 */ 587static inline int 588_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, 589 Elf_Addr *tp) 590{ 591 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 592 const Elf_Sym *def; 593 const Obj_Entry *defobj; 594 Elf_Addr value, offset; 595 unsigned long info = rela->r_info; 596 597 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 598 599 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 600 if (__predict_false(def == NULL)) 601 return -1; 602 if (__predict_false(def == &_rtld_sym_zero)) 603 return 0; 604 605 value = (Elf_Addr)(defobj->relocbase + def->st_value); 606 rdbg(("bind now/fixup in %s --> new=%p", 607 defobj->strtab + def->st_name, (void *)value)); 608 609 /* 610 * At the PLT entry pointed at by `where', we now construct a direct 611 * transfer to the now fully resolved function address. 612 * 613 * A PLT entry is supposed to start by looking like this: 614 * 615 * sethi %hi(. - .PLT0), %g1 616 * ba,a %xcc, .PLT1 617 * nop 618 * nop 619 * nop 620 * nop 621 * nop 622 * nop 623 * 624 * When we replace these entries we start from the last instruction 625 * and do it in reverse order so the last thing we do is replace the 626 * branch. That allows us to change this atomically. 627 * 628 * We now need to find out how far we need to jump. We have a choice 629 * of several different relocation techniques which are increasingly 630 * expensive. 631 */ 632 633 offset = ((Elf_Addr)where) - value; 634 if (rela->r_addend) { 635 Elf_Addr *ptr = (Elf_Addr *)where; 636 /* 637 * This entry is >= 32768. The relocations points to a 638 * PC-relative pointer to the bind_0 stub at the top of the 639 * PLT section. Update it to point to the target function. 640 */ 641 ptr[0] += value - (Elf_Addr)obj->pltgot; 642 643 } else if (offset <= (1L<<20) && (Elf_SOff)offset >= -(1L<<20)) { 644 /* 645 * We're within 1MB -- we can use a direct branch insn. 646 * 647 * We can generate this pattern: 648 * 649 * sethi %hi(. - .PLT0), %g1 650 * ba,a %xcc, addr 651 * nop 652 * nop 653 * nop 654 * nop 655 * nop 656 * nop 657 * 658 */ 659 where[1] = BAA | ((offset >> 2) & 0x3fffff); 660 __asm volatile("iflush %0+4" : : "r" (where)); 661 } else if (value < (1L<<32)) { 662 /* 663 * We're within 32-bits of address zero. 664 * 665 * The resulting code in the jump slot is: 666 * 667 * sethi %hi(. - .PLT0), %g1 668 * sethi %hi(addr), %g1 669 * jmp %g1+%lo(addr) 670 * nop 671 * nop 672 * nop 673 * nop 674 * nop 675 * 676 */ 677 where[2] = JMP | LOVAL(value, 0); 678 where[1] = SETHI | HIVAL(value, 10); 679 __asm volatile("iflush %0+8" : : "r" (where)); 680 __asm volatile("iflush %0+4" : : "r" (where)); 681 682 } else if ((Elf_SOff)value <= 0 && (Elf_SOff)value > -(1L<<32)) { 683 /* 684 * We're within 32-bits of address -1. 685 * 686 * The resulting code in the jump slot is: 687 * 688 * sethi %hi(. - .PLT0), %g1 689 * sethi %hix(addr), %g1 690 * xor %g1, %lox(addr), %g1 691 * jmp %g1 692 * nop 693 * nop 694 * nop 695 * nop 696 * 697 */ 698 where[3] = JMP; 699 where[2] = XOR | ((~value) & 0x00001fff); 700 where[1] = SETHI | HIVAL(~value, 10); 701 __asm volatile("iflush %0+12" : : "r" (where)); 702 __asm volatile("iflush %0+8" : : "r" (where)); 703 __asm volatile("iflush %0+4" : : "r" (where)); 704 705 } else if (offset <= (1L<<32) && (Elf_SOff)offset >= -((1L<<32) - 4)) { 706 /* 707 * We're within 32-bits -- we can use a direct call insn 708 * 709 * The resulting code in the jump slot is: 710 * 711 * sethi %hi(. - .PLT0), %g1 712 * mov %o7, %g1 713 * call (.+offset) 714 * mov %g1, %o7 715 * nop 716 * nop 717 * nop 718 * nop 719 * 720 */ 721 where[3] = MOV17; 722 where[2] = CALL | ((offset >> 4) & 0x3fffffff); 723 where[1] = MOV71; 724 __asm volatile("iflush %0+12" : : "r" (where)); 725 __asm volatile("iflush %0+8" : : "r" (where)); 726 __asm volatile("iflush %0+4" : : "r" (where)); 727 728 } else if (offset < (1L<<44)) { 729 /* 730 * We're within 44 bits. We can generate this pattern: 731 * 732 * The resulting code in the jump slot is: 733 * 734 * sethi %hi(. - .PLT0), %g1 735 * sethi %h44(addr), %g1 736 * or %g1, %m44(addr), %g1 737 * sllx %g1, 12, %g1 738 * jmp %g1+%l44(addr) 739 * nop 740 * nop 741 * nop 742 * 743 */ 744 where[4] = JMP | LOVAL(offset, 0); 745 where[3] = SLLX | 12; 746 where[2] = OR | (((offset) >> 12) & 0x00001fff); 747 where[1] = SETHI | HIVAL(offset, 22); 748 __asm volatile("iflush %0+16" : : "r" (where)); 749 __asm volatile("iflush %0+12" : : "r" (where)); 750 __asm volatile("iflush %0+8" : : "r" (where)); 751 __asm volatile("iflush %0+4" : : "r" (where)); 752 753 } else if ((Elf_SOff)offset < 0 && (Elf_SOff)offset > -(1L<<44)) { 754 /* 755 * We're within 44 bits. We can generate this pattern: 756 * 757 * The resulting code in the jump slot is: 758 * 759 * sethi %hi(. - .PLT0), %g1 760 * sethi %h44(-addr), %g1 761 * xor %g1, %m44(-addr), %g1 762 * sllx %g1, 12, %g1 763 * jmp %g1+%l44(addr) 764 * nop 765 * nop 766 * nop 767 * 768 */ 769 where[4] = JMP | LOVAL(offset, 0); 770 where[3] = SLLX | 12; 771 where[2] = XOR | (((~offset) >> 12) & 0x00001fff); 772 where[1] = SETHI | HIVAL(~offset, 22); 773 __asm volatile("iflush %0+16" : : "r" (where)); 774 __asm volatile("iflush %0+12" : : "r" (where)); 775 __asm volatile("iflush %0+8" : : "r" (where)); 776 __asm volatile("iflush %0+4" : : "r" (where)); 777 778 } else { 779 /* 780 * We need to load all 64-bits 781 * 782 * The resulting code in the jump slot is: 783 * 784 * sethi %hi(. - .PLT0), %g1 785 * sethi %hh(addr), %g1 786 * sethi %lm(addr), %g5 787 * or %g1, %hm(addr), %g1 788 * sllx %g1, 32, %g1 789 * or %g1, %g5, %g1 790 * jmp %g1+%lo(addr) 791 * nop 792 * 793 */ 794 where[6] = JMP | LOVAL(value, 0); 795 where[5] = ORG5; 796 where[4] = SLLX | 32; 797 where[3] = OR | LOVAL(value, 32); 798 where[2] = SETHIG5 | HIVAL(value, 10); 799 where[1] = SETHI | HIVAL(value, 42); 800 __asm volatile("iflush %0+24" : : "r" (where)); 801 __asm volatile("iflush %0+20" : : "r" (where)); 802 __asm volatile("iflush %0+16" : : "r" (where)); 803 __asm volatile("iflush %0+12" : : "r" (where)); 804 __asm volatile("iflush %0+8" : : "r" (where)); 805 __asm volatile("iflush %0+4" : : "r" (where)); 806 807 } 808 809 if (tp) 810 *tp = value; 811 812 return 0; 813} 814