1 /*- 2 * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com> 3 * All rights reserved. 4 * 5 * This software was developed by SRI International and the University of 6 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237 7 * ("CTSRD"), as part of the DARPA CRASH research programme. 8 * 9 * This software was developed by the University of Cambridge Computer 10 * Laboratory as part of the CTSRD Project, with support from the UK Higher 11 * Education Innovation Fund (HEIF). 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/types.h> 39 40 #include <stdlib.h> 41 42 #include "debug.h" 43 #include "rtld.h" 44 #include "rtld_printf.h" 45 46 /* 47 * It is possible for the compiler to emit relocations for unaligned data. 48 * We handle this situation with these inlines. 49 */ 50 #define RELOC_ALIGNED_P(x) \ 51 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0) 52 53 void _exit(int); 54 55 uint64_t 56 set_gp(Obj_Entry *obj) 57 { 58 uint64_t old; 59 SymLook req; 60 uint64_t gp; 61 int res; 62 63 __asm __volatile("mv %0, gp" : "=r"(old)); 64 65 symlook_init(&req, "_gp"); 66 req.ventry = NULL; 67 req.flags = SYMLOOK_EARLY; 68 res = symlook_obj(&req, obj); 69 70 if (res == 0) { 71 gp = req.sym_out->st_value; 72 __asm __volatile("mv gp, %0" :: "r"(gp)); 73 } 74 75 return (old); 76 } 77 78 void 79 init_pltgot(Obj_Entry *obj) 80 { 81 82 if (obj->pltgot != NULL) { 83 obj->pltgot[0] = (Elf_Addr)&_rtld_bind_start; 84 obj->pltgot[1] = (Elf_Addr)obj; 85 } 86 } 87 88 int 89 do_copy_relocations(Obj_Entry *dstobj) 90 { 91 const Obj_Entry *srcobj, *defobj; 92 const Elf_Rela *relalim; 93 const Elf_Rela *rela; 94 const Elf_Sym *srcsym; 95 const Elf_Sym *dstsym; 96 const void *srcaddr; 97 const char *name; 98 void *dstaddr; 99 SymLook req; 100 size_t size; 101 int res; 102 103 /* 104 * COPY relocs are invalid outside of the main program 105 */ 106 assert(dstobj->mainprog); 107 108 relalim = (const Elf_Rela *)((char *)dstobj->rela + 109 dstobj->relasize); 110 for (rela = dstobj->rela; rela < relalim; rela++) { 111 if (ELF_R_TYPE(rela->r_info) != R_RISCV_COPY) 112 continue; 113 114 dstaddr = (void *)(dstobj->relocbase + rela->r_offset); 115 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); 116 name = dstobj->strtab + dstsym->st_name; 117 size = dstsym->st_size; 118 119 symlook_init(&req, name); 120 req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); 121 req.flags = SYMLOOK_EARLY; 122 123 for (srcobj = globallist_next(dstobj); srcobj != NULL; 124 srcobj = globallist_next(srcobj)) { 125 res = symlook_obj(&req, srcobj); 126 if (res == 0) { 127 srcsym = req.sym_out; 128 defobj = req.defobj_out; 129 break; 130 } 131 } 132 if (srcobj == NULL) { 133 _rtld_error( 134 "Undefined symbol \"%s\" referenced from COPY relocation in %s", 135 name, dstobj->path); 136 return (-1); 137 } 138 139 srcaddr = (const void *)(defobj->relocbase + srcsym->st_value); 140 memcpy(dstaddr, srcaddr, size); 141 } 142 143 return (0); 144 } 145 146 /* 147 * Process the PLT relocations. 148 */ 149 int 150 reloc_plt(Obj_Entry *obj) 151 { 152 const Elf_Rela *relalim; 153 const Elf_Rela *rela; 154 155 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 156 for (rela = obj->pltrela; rela < relalim; rela++) { 157 Elf_Addr *where; 158 159 assert(ELF_R_TYPE(rela->r_info) == R_RISCV_JUMP_SLOT); 160 161 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 162 *where += (Elf_Addr)obj->relocbase; 163 } 164 165 return (0); 166 } 167 168 /* 169 * LD_BIND_NOW was set - force relocation for all jump slots 170 */ 171 int 172 reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) 173 { 174 const Obj_Entry *defobj; 175 const Elf_Rela *relalim; 176 const Elf_Rela *rela; 177 const Elf_Sym *def; 178 179 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 180 for (rela = obj->pltrela; rela < relalim; rela++) { 181 Elf_Addr *where; 182 183 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 184 switch(ELF_R_TYPE(rela->r_info)) { 185 case R_RISCV_JUMP_SLOT: 186 def = find_symdef(ELF_R_SYM(rela->r_info), obj, 187 &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); 188 if (def == NULL) { 189 dbg("reloc_jmpslots: sym not found"); 190 return (-1); 191 } 192 193 *where = (Elf_Addr)(defobj->relocbase + def->st_value); 194 break; 195 default: 196 _rtld_error("Unknown relocation type %x in jmpslot", 197 (unsigned int)ELF_R_TYPE(rela->r_info)); 198 return (-1); 199 } 200 } 201 202 return (0); 203 } 204 205 int 206 reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) 207 { 208 209 /* XXX not implemented */ 210 return (0); 211 } 212 213 int 214 reloc_gnu_ifunc(Obj_Entry *obj, int flags, 215 struct Struct_RtldLockState *lockstate) 216 { 217 218 /* XXX not implemented */ 219 return (0); 220 } 221 222 Elf_Addr 223 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj, 224 const Obj_Entry *obj, const Elf_Rel *rel) 225 { 226 227 assert(ELF_R_TYPE(rel->r_info) == R_RISCV_JUMP_SLOT); 228 229 if (*where != target && !ld_bind_not) 230 *where = target; 231 return (target); 232 } 233 234 /* 235 * Process non-PLT relocations 236 */ 237 int 238 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, 239 RtldLockState *lockstate) 240 { 241 const Obj_Entry *defobj; 242 const Elf_Rela *relalim; 243 const Elf_Rela *rela; 244 const Elf_Sym *def; 245 SymCache *cache; 246 Elf_Addr *where; 247 unsigned long symnum; 248 249 if ((flags & SYMLOOK_IFUNC) != 0) 250 /* XXX not implemented */ 251 return (0); 252 253 /* 254 * The dynamic loader may be called from a thread, we have 255 * limited amounts of stack available so we cannot use alloca(). 256 */ 257 if (obj == obj_rtld) 258 cache = NULL; 259 else 260 cache = calloc(obj->dynsymcount, sizeof(SymCache)); 261 /* No need to check for NULL here */ 262 263 relalim = (const Elf_Rela *)((caddr_t)obj->rela + obj->relasize); 264 for (rela = obj->rela; rela < relalim; rela++) { 265 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 266 symnum = ELF_R_SYM(rela->r_info); 267 268 switch (ELF_R_TYPE(rela->r_info)) { 269 case R_RISCV_JUMP_SLOT: 270 /* This will be handled by the plt/jmpslot routines */ 271 break; 272 case R_RISCV_NONE: 273 break; 274 case R_RISCV_64: 275 def = find_symdef(symnum, obj, &defobj, flags, cache, 276 lockstate); 277 if (def == NULL) 278 return (-1); 279 280 *where = (Elf_Addr)(defobj->relocbase + def->st_value + 281 rela->r_addend); 282 break; 283 case R_RISCV_TLS_DTPMOD64: 284 def = find_symdef(symnum, obj, &defobj, flags, cache, 285 lockstate); 286 if (def == NULL) 287 return -1; 288 289 *where += (Elf_Addr)defobj->tlsindex; 290 break; 291 case R_RISCV_COPY: 292 /* 293 * These are deferred until all other relocations have 294 * been done. All we do here is make sure that the 295 * COPY relocation is not in a shared library. They 296 * are allowed only in executable files. 297 */ 298 if (!obj->mainprog) { 299 _rtld_error("%s: Unexpected R_RISCV_COPY " 300 "relocation in shared library", obj->path); 301 return (-1); 302 } 303 break; 304 case R_RISCV_TLS_DTPREL64: 305 def = find_symdef(symnum, obj, &defobj, flags, cache, 306 lockstate); 307 if (def == NULL) 308 return (-1); 309 /* 310 * We lazily allocate offsets for static TLS as we 311 * see the first relocation that references the 312 * TLS block. This allows us to support (small 313 * amounts of) static TLS in dynamically loaded 314 * modules. If we run out of space, we generate an 315 * error. 316 */ 317 if (!defobj->tls_done) { 318 if (!allocate_tls_offset((Obj_Entry*) defobj)) { 319 _rtld_error( 320 "%s: No space available for static " 321 "Thread Local Storage", obj->path); 322 return (-1); 323 } 324 } 325 326 *where += (Elf_Addr)(def->st_value + rela->r_addend 327 - TLS_DTV_OFFSET); 328 break; 329 case R_RISCV_TLS_TPREL64: 330 def = find_symdef(symnum, obj, &defobj, flags, cache, 331 lockstate); 332 if (def == NULL) 333 return (-1); 334 335 /* 336 * We lazily allocate offsets for static TLS as we 337 * see the first relocation that references the 338 * TLS block. This allows us to support (small 339 * amounts of) static TLS in dynamically loaded 340 * modules. If we run out of space, we generate an 341 * error. 342 */ 343 if (!defobj->tls_done) { 344 if (!allocate_tls_offset((Obj_Entry*) defobj)) { 345 _rtld_error( 346 "%s: No space available for static " 347 "Thread Local Storage", obj->path); 348 return (-1); 349 } 350 } 351 352 *where = (def->st_value + rela->r_addend + 353 defobj->tlsoffset - TLS_TP_OFFSET); 354 break; 355 case R_RISCV_RELATIVE: 356 *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 357 break; 358 default: 359 rtld_printf("%s: Unhandled relocation %lu\n", 360 obj->path, ELF_R_TYPE(rela->r_info)); 361 return (-1); 362 } 363 } 364 365 return (0); 366 } 367 368 void 369 ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused) 370 { 371 } 372 373 void 374 allocate_initial_tls(Obj_Entry *objs) 375 { 376 Elf_Addr **tp; 377 378 /* 379 * Fix the size of the static TLS block by using the maximum 380 * offset allocated so far and adding a bit for dynamic modules to 381 * use. 382 */ 383 tls_static_space = tls_last_offset + tls_last_size + 384 RTLD_STATIC_TLS_EXTRA; 385 386 tp = (Elf_Addr **) ((char *)allocate_tls(objs, NULL, TLS_TCB_SIZE, 16) 387 + TLS_TP_OFFSET + TLS_TCB_SIZE); 388 389 __asm __volatile("mv tp, %0" :: "r"(tp)); 390 } 391 392 void * 393 __tls_get_addr(tls_index* ti) 394 { 395 char *_tp; 396 void *p; 397 398 __asm __volatile("mv %0, tp" : "=r" (_tp)); 399 400 p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)_tp - TLS_TP_OFFSET 401 - TLS_TCB_SIZE), ti->ti_module, ti->ti_offset); 402 403 return (p + TLS_DTV_OFFSET); 404 } 405