1168515Sgshapiro/* $NetBSD: mdreloc.c,v 1.70 2023/06/04 01:24:58 joerg Exp $ */ 2168515Sgshapiro 3168515Sgshapiro/*- 4168515Sgshapiro * Copyright (c) 2000 Eduardo Horvath. 5266527Sgshapiro * Copyright (c) 1999, 2002 The NetBSD Foundation, Inc. 6168515Sgshapiro * All rights reserved. 7168515Sgshapiro * 8168515Sgshapiro * This code is derived from software contributed to The NetBSD Foundation 9168515Sgshapiro * by Paul Kranenburg and by Charles M. Hannum. 10168515Sgshapiro * 11168515Sgshapiro * Redistribution and use in source and binary forms, with or without 12168515Sgshapiro * modification, are permitted provided that the following conditions 13168515Sgshapiro * are met: 14168515Sgshapiro * 1. Redistributions of source code must retain the above copyright 15168515Sgshapiro * notice, this list of conditions and the following disclaimer. 16168515Sgshapiro * 2. Redistributions in binary form must reproduce the above copyright 17168515Sgshapiro * notice, this list of conditions and the following disclaimer in the 18168515Sgshapiro * documentation and/or other materials provided with the distribution. 19168515Sgshapiro * 20168515Sgshapiro * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21168515Sgshapiro * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22168515Sgshapiro * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23168515Sgshapiro * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24168515Sgshapiro * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25168515Sgshapiro * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26168515Sgshapiro * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27168515Sgshapiro * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28168515Sgshapiro * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29168515Sgshapiro * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30168515Sgshapiro * POSSIBILITY OF SUCH DAMAGE. 31168515Sgshapiro */ 32168515Sgshapiro 33168515Sgshapiro#include <sys/cdefs.h> 34168515Sgshapiro#ifndef lint 35168515Sgshapiro__RCSID("$NetBSD: mdreloc.c,v 1.70 2023/06/04 01:24:58 joerg Exp $"); 36168515Sgshapiro#endif /* not lint */ 37168515Sgshapiro 38168515Sgshapiro#include <machine/elf_support.h> 39168515Sgshapiro 40168515Sgshapiro#include <errno.h> 41168515Sgshapiro#include <stdio.h> 42168515Sgshapiro#include <stdlib.h> 43168515Sgshapiro#include <string.h> 44168515Sgshapiro#include <unistd.h> 45168515Sgshapiro 46168515Sgshapiro#include "rtldenv.h" 47168515Sgshapiro#include "debug.h" 48168515Sgshapiro#include "rtld.h" 49168515Sgshapiro 50168515Sgshapiro/* 51168515Sgshapiro * The following table holds for each relocation type: 52168515Sgshapiro * - the width in bits of the memory location the relocation 53168515Sgshapiro * applies to (not currently used) 54168515Sgshapiro * - the number of bits the relocation value must be shifted to the 55168515Sgshapiro * right (i.e. discard least significant bits) to fit into 56168515Sgshapiro * the appropriate field in the instruction word. 57168515Sgshapiro * - flags indicating whether 58168515Sgshapiro * * the relocation involves a symbol 59168515Sgshapiro * * the relocation is relative to the current position 60168515Sgshapiro * * the relocation is for a GOT entry 61168515Sgshapiro * * the relocation is relative to the load address 62168515Sgshapiro * 63168515Sgshapiro */ 64168515Sgshapiro#define _RF_S 0x80000000 /* Resolve symbol */ 65168515Sgshapiro#define _RF_A 0x40000000 /* Use addend */ 66168515Sgshapiro#define _RF_P 0x20000000 /* Location relative */ 67168515Sgshapiro#define _RF_G 0x10000000 /* GOT offset */ 68168515Sgshapiro#define _RF_B 0x08000000 /* Load address relative */ 69168515Sgshapiro#define _RF_U 0x04000000 /* Unaligned */ 70168515Sgshapiro#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ 71168515Sgshapiro#define _RF_RS(s) ( (s) & 0xff) /* right shift */ 72168515Sgshapirostatic const int reloc_target_flags[R_TYPE(TLS_TPOFF64)+1] = { 73168515Sgshapiro 0, /* NONE */ 74168515Sgshapiro _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ 75168515Sgshapiro _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ 76168515Sgshapiro _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ 77168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ 78168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ 79168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ 80168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ 81168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ 82168515Sgshapiro _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ 83168515Sgshapiro _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ 84168515Sgshapiro _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ 85168515Sgshapiro _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ 86168515Sgshapiro _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ 87261194Sgshapiro _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ 88168515Sgshapiro _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ 89168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ 90168515Sgshapiro _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ 91168515Sgshapiro _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ 92168515Sgshapiro _RF_SZ(32) | _RF_RS(0), /* COPY */ 93168515Sgshapiro _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* GLOB_DAT */ 94168515Sgshapiro _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ 95 _RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */ 96 _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ 97 98 _RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */ 99 _RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */ 100 _RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ 101 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ 102 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */ 103 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */ 104 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */ 105 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */ 106 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */ 107 _RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ 108 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */ 109 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */ 110 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */ 111 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */ 112 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */ 113 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */ 114 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */ 115 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */ 116 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ 117 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */ 118 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */ 119 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */ 120 _RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */ 121 _RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */ 122 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */ 123 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */ 124 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */ 125 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */ 126 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */ 127 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */ 128 _RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */ 129 _RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */ 130/* TLS relocs not represented here! */ 131}; 132 133#ifdef RTLD_DEBUG_RELOC 134static const char *reloc_names[] = { 135 "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", 136 "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", 137 "22", "13", "LO10", "GOT10", "GOT13", 138 "GOT22", "PC10", "PC22", "WPLT30", "COPY", 139 "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", "PLT32", 140 "HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32", 141 "10", "11", "64", "OLO10", "HH22", 142 "HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22", 143 "WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6", 144 "DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44", 145 "L44", "REGISTER", "UA64", "UA16", 146 "TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL", 147 "TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL", 148 "TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22", 149 "TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22", 150 "TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32", 151 "TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64", 152}; 153#endif 154 155#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) 156#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) 157#define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) 158#define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) 159#define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) 160#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) 161#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) 162#define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22)) 163 164static const long reloc_target_bitmask[] = { 165#define _BM(x) (~(-(1ULL << (x)))) 166 0, /* NONE */ 167 _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ 168 _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ 169 _BM(30), _BM(22), /* WDISP30, WDISP22 */ 170 _BM(22), _BM(22), /* HI22, _22 */ 171 _BM(13), _BM(10), /* RELOC_13, _LO10 */ 172 _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ 173 _BM(10), _BM(22), /* _PC10, _PC22 */ 174 _BM(30), 0, /* _WPLT30, _COPY */ 175 -1, _BM(32), -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ 176 _BM(32), _BM(32), /* _UA32, PLT32 */ 177 _BM(22), _BM(10), /* _HIPLT22, LOPLT10 */ 178 _BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */ 179 _BM(10), _BM(11), -1, /* _10, _11, _64 */ 180 _BM(13), _BM(22), /* _OLO10, _HH22 */ 181 _BM(10), _BM(22), /* _HM10, _LM22 */ 182 _BM(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */ 183 _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ 184 -1, /* GLOB_JMP */ 185 _BM(7), _BM(5), _BM(6), /* _7, _5, _6 */ 186 -1, -1, /* DISP64, PLT64 */ 187 _BM(22), _BM(13), /* HIX22, LOX10 */ 188 _BM(22), _BM(10), _BM(12), /* H44, M44, L44 */ 189 -1, -1, _BM(16), /* REGISTER, UA64, UA16 */ 190#undef _BM 191}; 192#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) 193 194/* 195 * Instruction templates: 196 */ 197 198 199/* %hi(v)/%lo(v) with variable shift */ 200#define HIVAL(v, s) (((v) >> (s)) & 0x003fffff) 201#define LOVAL(v, s) (((v) >> (s)) & 0x000003ff) 202 203void _rtld_bind_start_0(long, long); 204void _rtld_bind_start_1(long, long); 205void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 206caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 207 208/* 209 * Install rtld function call into this PLT slot. 210 */ 211#define SAVE 0x9de3bf50 /* i.e. `save %sp,-176,%sp' */ 212#define SETHI_l0 0x21000000 213#define SETHI_l1 0x23000000 214#define OR_l0_l0 0xa0142000 215#define SLLX_l0_32_l0 0xa12c3020 216#define OR_l0_l1_l0 0xa0140011 217#define JMPL_l0_o0 0x91c42000 218#define MOV_g1_o1 0x92100001 219 220void _rtld_install_plt(Elf_Word *, Elf_Addr); 221static inline int _rtld_relocate_plt_object(const Obj_Entry *, 222 const Elf_Rela *, Elf_Addr *); 223 224void 225_rtld_install_plt(Elf_Word *pltgot, Elf_Addr proc) 226{ 227 pltgot[0] = SAVE; 228 pltgot[1] = SETHI_l0 | HIVAL(proc, 42); 229 pltgot[2] = SETHI_l1 | HIVAL(proc, 10); 230 pltgot[3] = OR_l0_l0 | LOVAL(proc, 32); 231 pltgot[4] = SLLX_l0_32_l0; 232 pltgot[5] = OR_l0_l1_l0; 233 pltgot[6] = JMPL_l0_o0 | LOVAL(proc, 0); 234 pltgot[7] = MOV_g1_o1; 235} 236 237void 238_rtld_setup_pltgot(const Obj_Entry *obj) 239{ 240 /* 241 * On sparc64 we got troubles. 242 * 243 * Instructions are 4 bytes long. 244 * Elf[64]_Addr is 8 bytes long, so are our pltglot[] 245 * array entries. 246 * Each PLT entry jumps to PLT0 to enter the dynamic 247 * linker. 248 * Loading an arbitrary 64-bit pointer takes 6 249 * instructions and 2 registers. 250 * 251 * Somehow we need to issue a save to get a new stack 252 * frame, load the address of the dynamic linker, and 253 * jump there, in 8 instructions or less. 254 * 255 * Oh, we need to fill out both PLT0 and PLT1. 256 */ 257 { 258 Elf_Word *entry = (Elf_Word *)obj->pltgot; 259 260 /* Install in entries 0 and 1 */ 261 _rtld_install_plt(&entry[0], (Elf_Addr) &_rtld_bind_start_0); 262 _rtld_install_plt(&entry[8], (Elf_Addr) &_rtld_bind_start_1); 263 264 /* 265 * Install the object reference in first slot 266 * of entry 2. 267 */ 268 obj->pltgot[8] = (Elf_Addr) obj; 269 } 270} 271 272void 273_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 274{ 275 const Elf_Rela *rela = 0, *relalim; 276 Elf_Addr relasz = 0; 277 Elf_Addr *where; 278 279 for (; dynp->d_tag != DT_NULL; dynp++) { 280 switch (dynp->d_tag) { 281 case DT_RELA: 282 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 283 break; 284 case DT_RELASZ: 285 relasz = dynp->d_un.d_val; 286 break; 287 } 288 } 289 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 290 for (; rela < relalim; rela++) { 291 where = (Elf_Addr *)(relocbase + rela->r_offset); 292 *where = (Elf_Addr)(relocbase + rela->r_addend); 293 } 294} 295 296int 297_rtld_relocate_nonplt_objects(Obj_Entry *obj) 298{ 299 const Elf_Rela *rela; 300 const Elf_Sym *def = NULL; 301 const Obj_Entry *defobj = NULL; 302 unsigned long last_symnum = ULONG_MAX; 303 304 for (rela = obj->rela; rela < obj->relalim; rela++) { 305 Elf_Addr *where; 306 Elf_Word type; 307 Elf_Addr value = 0, mask; 308 unsigned long symnum; 309 310 where = (Elf_Addr *) (obj->relocbase + rela->r_offset); 311 312 type = ELF_R_TYPE(rela->r_info); 313 if (type == R_TYPE(NONE)) 314 continue; 315 316 /* OLO10 relocations have extra info */ 317 if ((type & 0x00ff) == R_SPARC_OLO10) 318 type = R_SPARC_OLO10; 319 320 /* We do JMP_SLOTs in _rtld_bind() below */ 321 if (type == R_TYPE(JMP_SLOT)) 322 continue; 323 324 /* IFUNC relocations are handled in _rtld_call_ifunc */ 325 if (type == R_TYPE(IRELATIVE)) { 326 if (obj->ifunc_remaining_nonplt == 0) { 327 obj->ifunc_remaining_nonplt = 328 obj->relalim - rela; 329 } 330 continue; 331 } 332 333 /* COPY relocs are also handled elsewhere */ 334 if (type == R_TYPE(COPY)) 335 continue; 336 337 /* 338 * We use the fact that relocation types are an `enum' 339 * Note: R_SPARC_TLS_TPOFF64 is currently numerically largest. 340 */ 341 if (type > R_TYPE(TLS_TPOFF64)) { 342 dbg(("unknown relocation type %x at %p", type, rela)); 343 return -1; 344 } 345 346 value = rela->r_addend; 347 348 if (RELOC_RESOLVE_SYMBOL(type) || RELOC_TLS(type)) { 349 symnum = ELF_R_SYM(rela->r_info); 350 if (last_symnum != symnum) { 351 last_symnum = symnum; 352 def = _rtld_find_symdef(symnum, obj, &defobj, 353 false); 354 if (def == NULL) 355 return -1; 356 } 357 } 358 359 /* 360 * Handle TLS relocations here, they are different. 361 */ 362 if (RELOC_TLS(type)) { 363 switch (type) { 364 case R_TYPE(TLS_DTPMOD64): 365 *where = (Elf64_Addr)defobj->tlsindex; 366 367 rdbg(("TLS_DTPMOD64 %s in %s --> %p", 368 obj->strtab + 369 obj->symtab[symnum].st_name, 370 obj->path, (void *)*where)); 371 372 break; 373 374 case R_TYPE(TLS_DTPOFF64): 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 if (!defobj->tls_static && 387 _rtld_tls_offset_allocate(__UNCONST(defobj))) 388 return -1; 389 390 *where = (Elf64_Addr)(def->st_value - 391 defobj->tlsoffset + rela->r_addend); 392 393 rdbg(("TLS_TPOFF64 %s in %s --> %p", 394 obj->strtab + obj->symtab[symnum].st_name, 395 obj->path, (void *)*where)); 396 397 break; 398 } 399 continue; 400 } 401 402 /* 403 * Handle relative relocs here, as an optimization. 404 */ 405 if (type == R_TYPE(RELATIVE)) { 406 *where = (Elf_Addr)(obj->relocbase + value); 407 rdbg(("RELATIVE in %s --> %p", obj->path, 408 (void *)*where)); 409 continue; 410 } 411 412 if (RELOC_RESOLVE_SYMBOL(type)) { 413 /* Add in the symbol's absolute address */ 414 value += (Elf_Addr)(defobj->relocbase + def->st_value); 415 } 416 417 if (type == R_SPARC_OLO10) { 418 value = (value & 0x3ff) 419 + (((Elf64_Xword)rela->r_info<<32)>>40); 420 } 421 422 if (RELOC_PC_RELATIVE(type)) { 423 value -= (Elf_Addr)where; 424 } 425 426 if (RELOC_BASE_RELATIVE(type)) { 427 /* 428 * Note that even though sparcs use `Elf_rela' 429 * exclusively we still need the implicit memory addend 430 * in relocations referring to GOT entries. 431 * Undoubtedly, someone f*cked this up in the distant 432 * past, and now we're stuck with it in the name of 433 * compatibility for all eternity.. 434 * 435 * In any case, the implicit and explicit should be 436 * mutually exclusive. We provide a check for that 437 * here. 438 */ 439#ifdef DIAGNOSTIC 440 if (value != 0 && *where != 0) { 441 xprintf("BASE_REL(%s): where=%p, *where 0x%lx, " 442 "addend=0x%lx, base %p\n", 443 obj->path, where, *where, 444 rela->r_addend, obj->relocbase); 445 } 446#endif 447 /* XXXX -- apparently we ignore the preexisting value */ 448 value += (Elf_Addr)(obj->relocbase); 449 } 450 451 mask = RELOC_VALUE_BITMASK(type); 452 value >>= RELOC_VALUE_RIGHTSHIFT(type); 453 value &= mask; 454 455 if (RELOC_UNALIGNED(type)) { 456 /* Handle unaligned relocations. */ 457 Elf_Addr tmp = 0; 458 char *ptr = (char *)where; 459 int i, size = RELOC_TARGET_SIZE(type)/8; 460 461 /* Read it in one byte at a time. */ 462 for (i=0; i<size; i++) 463 tmp = (tmp << 8) | ptr[i]; 464 465 tmp &= ~mask; 466 tmp |= value; 467 468 /* Write it back out. */ 469 for (i=0; i<size; i++) 470 ptr[i] = ((tmp >> (8*i)) & 0xff); 471#ifdef RTLD_DEBUG_RELOC 472 value = (Elf_Addr)tmp; 473#endif 474 475 } else if (RELOC_TARGET_SIZE(type) > 32) { 476 *where &= ~mask; 477 *where |= value; 478#ifdef RTLD_DEBUG_RELOC 479 value = (Elf_Addr)*where; 480#endif 481 } else { 482 Elf32_Addr *where32 = (Elf32_Addr *)where; 483 484 *where32 &= ~mask; 485 *where32 |= value; 486#ifdef RTLD_DEBUG_RELOC 487 value = (Elf_Addr)*where32; 488#endif 489 } 490 491#ifdef RTLD_DEBUG_RELOC 492 if (RELOC_RESOLVE_SYMBOL(type)) { 493 rdbg(("%s %s in %s --> %p in %s", reloc_names[type], 494 obj->strtab + obj->symtab[symnum].st_name, 495 obj->path, (void *)value, defobj->path)); 496 } else { 497 rdbg(("%s in %s --> %p", reloc_names[type], 498 obj->path, (void *)value)); 499 } 500#endif 501 } 502 return (0); 503} 504 505int 506_rtld_relocate_plt_lazy(Obj_Entry *obj) 507{ 508 const Elf_Rela *rela; 509 510 for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { 511 if (ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_IREL)) 512 obj->ifunc_remaining = obj->pltrelalim - rela + 1; 513 } 514 515 return 0; 516} 517 518caddr_t 519_rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 520{ 521 const Elf_Rela *rela = obj->pltrela + reloff; 522 Elf_Addr result; 523 int err; 524 525 result = 0; /* XXX gcc */ 526 527 if (ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_SLOT) || 528 ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_IREL)) { 529 /* 530 * XXXX 531 * 532 * The first four PLT entries are reserved. There is some 533 * disagreement whether they should have associated relocation 534 * entries. Both the SPARC 32-bit and 64-bit ELF 535 * specifications say that they should have relocation entries, 536 * but the 32-bit SPARC binutils do not generate them, and now 537 * the 64-bit SPARC binutils have stopped generating them too. 538 * 539 * So, to provide binary compatibility, we will check the first 540 * entry, if it is reserved it should not be of the type 541 * JMP_SLOT or JMP_REL. If it is either of those, then 542 * the 4 reserved entries were not generated and our index 543 * is 4 entries too far. 544 */ 545 rela -= 4; 546 } 547 548 _rtld_shared_enter(); 549 err = _rtld_relocate_plt_object(obj, rela, &result); 550 if (err) 551 _rtld_die(); 552 _rtld_shared_exit(); 553 554 return (caddr_t)result; 555} 556 557int 558_rtld_relocate_plt_objects(const Obj_Entry *obj) 559{ 560 const Elf_Rela *rela; 561 562 rela = obj->pltrela; 563 564 /* 565 * Check for first four reserved entries - and skip them. 566 * See above for details. 567 */ 568 if (ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_SLOT) && 569 ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_IREL)) 570 rela += 4; 571 572 for (; rela < obj->pltrelalim; rela++) 573 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 574 return -1; 575 576 return 0; 577} 578 579static inline void 580_rtld_write_plt(Elf_Word *where, Elf_Addr value, const Elf_Rela *rela, 581 const Obj_Entry *obj) 582{ 583 if (rela && rela->r_addend) { 584 Elf_Addr *ptr = (Elf_Addr *)where; 585 /* 586 * This entry is >= 32768. The relocations points to a 587 * PC-relative pointer to the bind_0 stub at the top of the 588 * PLT section. Update it to point to the target function. 589 */ 590 ptr[0] += value - (Elf_Addr)obj->pltgot; 591 } else { 592 sparc_write_branch(where + 1, (void *)value); 593 } 594} 595 596/* 597 * New inline function that is called by _rtld_relocate_plt_object and 598 * _rtld_bind 599 */ 600static inline int 601_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, 602 Elf_Addr *tp) 603{ 604 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 605 const Elf_Sym *def; 606 const Obj_Entry *defobj; 607 Elf_Addr value; 608 unsigned long info = rela->r_info; 609 610 if (ELF_R_TYPE(info) == R_TYPE(JMP_IREL)) 611 return 0; 612 613 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 614 615 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 616 if (__predict_false(def == NULL)) 617 return -1; 618 if (__predict_false(def == &_rtld_sym_zero)) 619 return 0; 620 621 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 622 if (tp == NULL) 623 return 0; 624 value = _rtld_resolve_ifunc(defobj, def); 625 } else { 626 value = (Elf_Addr)(defobj->relocbase + def->st_value); 627 } 628 rdbg(("bind now/fixup in %s at %p --> new=%p", 629 defobj->strtab + def->st_name, (void*)where, (void *)value)); 630 631 _rtld_write_plt(where, value, rela, obj); 632 633 if (tp) 634 *tp = value; 635 636 return 0; 637} 638