1 /*- 2 * Copyright (c) 2015-2017 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 uint64_t 54 set_gp(Obj_Entry *obj) 55 { 56 uint64_t old; 57 SymLook req; 58 uint64_t gp; 59 int res; 60 61 __asm __volatile("mv %0, gp" : "=r"(old)); 62 63 symlook_init(&req, "__global_pointer$"); 64 req.ventry = NULL; 65 req.flags = SYMLOOK_EARLY; 66 res = symlook_obj(&req, obj); 67 68 if (res == 0) { 69 gp = req.sym_out->st_value; 70 __asm __volatile("mv gp, %0" :: "r"(gp)); 71 } 72 73 return (old); 74 } 75 76 void 77 init_pltgot(Obj_Entry *obj) 78 { 79 80 if (obj->pltgot != NULL) { 81 obj->pltgot[0] = (Elf_Addr)&_rtld_bind_start; 82 obj->pltgot[1] = (Elf_Addr)obj; 83 } 84 } 85 86 int 87 do_copy_relocations(Obj_Entry *dstobj) 88 { 89 const Obj_Entry *srcobj, *defobj; 90 const Elf_Rela *relalim; 91 const Elf_Rela *rela; 92 const Elf_Sym *srcsym; 93 const Elf_Sym *dstsym; 94 const void *srcaddr; 95 const char *name; 96 void *dstaddr; 97 SymLook req; 98 size_t size; 99 int res; 100 101 /* 102 * COPY relocs are invalid outside of the main program 103 */ 104 assert(dstobj->mainprog); 105 106 relalim = (const Elf_Rela *)((const char *)dstobj->rela + 107 dstobj->relasize); 108 for (rela = dstobj->rela; rela < relalim; rela++) { 109 if (ELF_R_TYPE(rela->r_info) != R_RISCV_COPY) 110 continue; 111 112 dstaddr = (void *)(dstobj->relocbase + rela->r_offset); 113 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); 114 name = dstobj->strtab + dstsym->st_name; 115 size = dstsym->st_size; 116 117 symlook_init(&req, name); 118 req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); 119 req.flags = SYMLOOK_EARLY; 120 121 for (srcobj = globallist_next(dstobj); srcobj != NULL; 122 srcobj = globallist_next(srcobj)) { 123 res = symlook_obj(&req, srcobj); 124 if (res == 0) { 125 srcsym = req.sym_out; 126 defobj = req.defobj_out; 127 break; 128 } 129 } 130 if (srcobj == NULL) { 131 _rtld_error( 132 "Undefined symbol \"%s\" referenced from COPY relocation in %s", 133 name, dstobj->path); 134 return (-1); 135 } 136 137 srcaddr = (const void *)(defobj->relocbase + srcsym->st_value); 138 memcpy(dstaddr, srcaddr, size); 139 } 140 141 return (0); 142 } 143 144 /* 145 * Process the PLT relocations. 146 */ 147 int 148 reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused) 149 { 150 const Elf_Rela *relalim; 151 const Elf_Rela *rela; 152 153 relalim = (const Elf_Rela *)((const char *)obj->pltrela + 154 obj->pltrelasize); 155 for (rela = obj->pltrela; rela < relalim; rela++) { 156 Elf_Addr *where; 157 158 assert(ELF_R_TYPE(rela->r_info) == R_RISCV_JUMP_SLOT); 159 160 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 161 *where += (Elf_Addr)obj->relocbase; 162 } 163 164 return (0); 165 } 166 167 /* 168 * LD_BIND_NOW was set - force relocation for all jump slots 169 */ 170 int 171 reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) 172 { 173 const Obj_Entry *defobj; 174 const Elf_Rela *relalim; 175 const Elf_Rela *rela; 176 const Elf_Sym *def; 177 178 relalim = (const Elf_Rela *)((const char *)obj->pltrela + 179 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 __unused, 207 struct Struct_RtldLockState *lockstate __unused) 208 { 209 210 /* XXX not implemented */ 211 return (0); 212 } 213 214 int 215 reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused, 216 struct Struct_RtldLockState *lockstate __unused) 217 { 218 219 /* XXX not implemented */ 220 return (0); 221 } 222 223 Elf_Addr 224 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, 225 const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused, 226 const Elf_Rel *rel) 227 { 228 229 assert(ELF_R_TYPE(rel->r_info) == R_RISCV_JUMP_SLOT); 230 231 if (*where != target && !ld_bind_not) 232 *where = target; 233 return (target); 234 } 235 236 /* 237 * Process non-PLT relocations 238 */ 239 int 240 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, 241 RtldLockState *lockstate) 242 { 243 const Obj_Entry *defobj; 244 const Elf_Rela *relalim; 245 const Elf_Rela *rela; 246 const Elf_Sym *def; 247 SymCache *cache; 248 Elf_Addr *where; 249 unsigned long symnum; 250 251 if ((flags & SYMLOOK_IFUNC) != 0) 252 /* XXX not implemented */ 253 return (0); 254 255 /* 256 * The dynamic loader may be called from a thread, we have 257 * limited amounts of stack available so we cannot use alloca(). 258 */ 259 if (obj == obj_rtld) 260 cache = NULL; 261 else 262 cache = calloc(obj->dynsymcount, sizeof(SymCache)); 263 /* No need to check for NULL here */ 264 265 relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); 266 for (rela = obj->rela; rela < relalim; rela++) { 267 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 268 symnum = ELF_R_SYM(rela->r_info); 269 270 switch (ELF_R_TYPE(rela->r_info)) { 271 case R_RISCV_JUMP_SLOT: 272 /* This will be handled by the plt/jmpslot routines */ 273 break; 274 case R_RISCV_NONE: 275 break; 276 case R_RISCV_64: 277 def = find_symdef(symnum, obj, &defobj, flags, cache, 278 lockstate); 279 if (def == NULL) 280 return (-1); 281 282 *where = (Elf_Addr)(defobj->relocbase + def->st_value + 283 rela->r_addend); 284 break; 285 case R_RISCV_TLS_DTPMOD64: 286 def = find_symdef(symnum, obj, &defobj, flags, cache, 287 lockstate); 288 if (def == NULL) 289 return -1; 290 291 *where += (Elf_Addr)defobj->tlsindex; 292 break; 293 case R_RISCV_COPY: 294 /* 295 * These are deferred until all other relocations have 296 * been done. All we do here is make sure that the 297 * COPY relocation is not in a shared library. They 298 * are allowed only in executable files. 299 */ 300 if (!obj->mainprog) { 301 _rtld_error("%s: Unexpected R_RISCV_COPY " 302 "relocation in shared library", obj->path); 303 return (-1); 304 } 305 break; 306 case R_RISCV_TLS_DTPREL64: 307 def = find_symdef(symnum, obj, &defobj, flags, cache, 308 lockstate); 309 if (def == NULL) 310 return (-1); 311 /* 312 * We lazily allocate offsets for static TLS as we 313 * see the first relocation that references the 314 * TLS block. This allows us to support (small 315 * amounts of) static TLS in dynamically loaded 316 * modules. If we run out of space, we generate an 317 * error. 318 */ 319 if (!defobj->tls_done) { 320 if (!allocate_tls_offset( 321 __DECONST(Obj_Entry *, defobj))) { 322 _rtld_error( 323 "%s: No space available for static " 324 "Thread Local Storage", obj->path); 325 return (-1); 326 } 327 } 328 329 *where += (Elf_Addr)(def->st_value + rela->r_addend 330 - TLS_DTV_OFFSET); 331 break; 332 case R_RISCV_TLS_TPREL64: 333 def = find_symdef(symnum, obj, &defobj, flags, cache, 334 lockstate); 335 if (def == NULL) 336 return (-1); 337 338 /* 339 * We lazily allocate offsets for static TLS as we 340 * see the first relocation that references the 341 * TLS block. This allows us to support (small 342 * amounts of) static TLS in dynamically loaded 343 * modules. If we run out of space, we generate an 344 * error. 345 */ 346 if (!defobj->tls_done) { 347 if (!allocate_tls_offset( 348 __DECONST(Obj_Entry *, defobj))) { 349 _rtld_error( 350 "%s: No space available for static " 351 "Thread Local Storage", obj->path); 352 return (-1); 353 } 354 } 355 356 *where = (def->st_value + rela->r_addend + 357 defobj->tlsoffset - TLS_TP_OFFSET); 358 break; 359 case R_RISCV_RELATIVE: 360 *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 361 break; 362 default: 363 rtld_printf("%s: Unhandled relocation %lu\n", 364 obj->path, ELF_R_TYPE(rela->r_info)); 365 return (-1); 366 } 367 } 368 369 return (0); 370 } 371 372 void 373 ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused) 374 { 375 376 } 377 378 void 379 pre_init(void) 380 { 381 382 } 383 384 void 385 allocate_initial_tls(Obj_Entry *objs) 386 { 387 Elf_Addr **tp; 388 389 /* 390 * Fix the size of the static TLS block by using the maximum 391 * offset allocated so far and adding a bit for dynamic modules to 392 * use. 393 */ 394 tls_static_space = tls_last_offset + tls_last_size + 395 RTLD_STATIC_TLS_EXTRA; 396 397 tp = (Elf_Addr **)((char *)allocate_tls(objs, NULL, TLS_TCB_SIZE, 16) 398 + TLS_TP_OFFSET + TLS_TCB_SIZE); 399 400 __asm __volatile("mv tp, %0" :: "r"(tp)); 401 } 402 403 void * 404 __tls_get_addr(tls_index* ti) 405 { 406 char *_tp; 407 void *p; 408 409 __asm __volatile("mv %0, tp" : "=r" (_tp)); 410 411 p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)_tp - TLS_TP_OFFSET 412 - TLS_TCB_SIZE), ti->ti_module, ti->ti_offset); 413 414 return ((char*)p + TLS_DTV_OFFSET); 415 } 416