1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 /* 30 * SPARC relocation code. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/param.h> 35 #include <sys/sysmacros.h> 36 #include <sys/systm.h> 37 #include <sys/user.h> 38 #include <sys/bootconf.h> 39 #include <sys/modctl.h> 40 #include <sys/elf.h> 41 #include <sys/kobj.h> 42 #include <sys/kobj_impl.h> 43 #include <sys/tnf.h> 44 #include <sys/tnf_probe.h> 45 #include <sys/sdt.h> 46 47 #include "reloc.h" 48 49 50 /* 51 * Probe discovery support 52 */ 53 #define PROBE_MARKER_SYMBOL "__tnf_probe_version_1" 54 #define TAG_MARKER_SYMBOL "__tnf_tag_version_1" 55 56 extern int tnf_splice_probes(int, tnf_probe_control_t *, tnf_tag_data_t *); 57 58 /* 59 * The kernel run-time linker calls this to try to resolve a reference 60 * it can't otherwise resolve. We see if it's marking a probe control 61 * block or a probe tag block; if so, we do the resolution and return 0. 62 * If not, we return 1 to show that we can't resolve it, either. 63 */ 64 static int 65 tnf_reloc_resolve(char *symname, Addr *value_p, 66 Elf64_Sxword *addend_p, 67 long offset, 68 tnf_probe_control_t **probelist, 69 tnf_tag_data_t **taglist) 70 { 71 if (strcmp(symname, PROBE_MARKER_SYMBOL) == 0) { 72 *addend_p = 0; 73 ((tnf_probe_control_t *)offset)->next = *probelist; 74 *probelist = (tnf_probe_control_t *)offset; 75 return (0); 76 } 77 if (strcmp(symname, TAG_MARKER_SYMBOL) == 0) { 78 *addend_p = 0; 79 *value_p = (Addr)*taglist; 80 *taglist = (tnf_tag_data_t *)offset; 81 return (0); 82 } 83 return (1); 84 } 85 86 #define SDT_RESTORE_MASK 0xc1f80000 87 #define SDT_RESTORE 0x81e80000 88 #define SDT_NOP 0x01000000 89 #define SDT_RET 0x81c7e008 90 #define SDT_RETL 0x81c3e008 91 #define SDT_RDO7_MASK 0xbf000000 92 #define SDT_RDO7 0x9e000000 93 94 static int 95 sdt_reloc_resolve(struct module *mp, char *symname, uint32_t *instr, long roff) 96 { 97 sdt_probedesc_t *sdp; 98 99 /* 100 * The "statically defined tracing" (SDT) provider for DTrace uses 101 * a mechanism similar to TNF, but somewhat simpler. (Surprise, 102 * surprise.) The SDT mechanism works by replacing calls to the 103 * undefined routine __dtrace_probe_[name] with nop instructions. 104 * The relocations are logged, and SDT itself will later patch the 105 * running binary appropriately. 106 */ 107 if (strncmp(symname, sdt_prefix, strlen(sdt_prefix)) != 0) 108 return (1); 109 110 symname += strlen(sdt_prefix); 111 112 sdp = kobj_alloc(sizeof (sdt_probedesc_t), KM_WAIT); 113 sdp->sdpd_name = kobj_alloc(strlen(symname) + 1, KM_WAIT); 114 bcopy(symname, sdp->sdpd_name, strlen(symname) + 1); 115 116 if ((uint32_t *)roff == instr) { 117 /* 118 * This isn't an offset -- it's an absolute value. (This is 119 * typically only true for "unix".) We need to convert the 120 * value into an offset from mp->text. 121 */ 122 roff -= (uintptr_t)mp->text; 123 } 124 125 sdp->sdpd_offset = roff; 126 127 sdp->sdpd_next = mp->sdt_probes; 128 mp->sdt_probes = sdp; 129 130 /* 131 * If the next instruction is a restore (any variant), then the probe 132 * point is being tail-called. Instead of patching the call to be a 133 * NOP, we must patch it to be a ret. If the next instruction is 134 * writing to %o7, it must be a tail call from a leaf; we must patch 135 * the instruction to be a retl. 136 */ 137 if ((*(instr + 1) & SDT_RESTORE_MASK) == SDT_RESTORE) { 138 *instr = SDT_RET; 139 } else if ((*(instr + 1) & SDT_RDO7_MASK) == SDT_RDO7) { 140 *instr = SDT_RETL; 141 } else { 142 *instr = SDT_NOP; 143 } 144 145 return (0); 146 } 147 148 int 149 /* ARGSUSED2 */ 150 do_relocate( 151 struct module *mp, 152 char *reltbl, 153 Word relshtype, 154 int nreloc, 155 int relocsize, 156 Addr baseaddr) 157 { 158 Word stndx; 159 long off, roff; 160 uintptr_t reladdr, rend; 161 uint_t rtype; 162 Elf64_Sxword addend; 163 Addr value, destination; 164 Sym *symref; 165 int symnum; 166 int err = 0; 167 tnf_probe_control_t *probelist = NULL; 168 tnf_tag_data_t *taglist = NULL; 169 170 reladdr = (uintptr_t)reltbl; 171 rend = reladdr + nreloc * relocsize; 172 173 #ifdef KOBJ_DEBUG 174 if (kobj_debug & D_RELOCATIONS) { 175 _kobj_printf(ops, "krtld:\ttype\t\t\toffset\t addend" 176 " symbol\n"); 177 _kobj_printf(ops, "krtld:\t\t\t\t\t value\n"); 178 } 179 #endif 180 destination = baseaddr; 181 182 /* 183 * If this machine is loading a module through an alternate address 184 * we need to compute the spot where the actual relocation will 185 * take place. 186 */ 187 if (mp->destination) { 188 int i; 189 Shdr * shp; 190 shp = (Shdr *)mp->shdrs; 191 for (i = 0; i < mp->hdr.e_shnum; i++, shp++) { 192 if (shp->sh_addr == baseaddr) { 193 if ((shp->sh_flags & SHF_ALLOC) && 194 !(shp->sh_flags & SHF_WRITE)) 195 destination = (Addr)mp->destination + 196 (baseaddr - (Addr)mp->text); 197 break; 198 } 199 } 200 } 201 202 symnum = -1; 203 /* loop through relocations */ 204 while (reladdr < rend) { 205 206 symnum++; 207 rtype = ELF_R_TYPE(((Rela *)reladdr)->r_info); 208 roff = off = ((Rela *)reladdr)->r_offset; 209 stndx = ELF_R_SYM(((Rela *)reladdr)->r_info); 210 if (stndx >= mp->nsyms) { 211 _kobj_printf(ops, 212 "do_relocate: bad strndx %d\n", symnum); 213 return (-1); 214 } 215 if ((rtype > R_SPARC_NUM) || IS_TLS_INS(rtype)) { 216 _kobj_printf(ops, "krtld: invalid relocation type %d", 217 rtype); 218 _kobj_printf(ops, " at 0x%llx:", off); 219 _kobj_printf(ops, " file=%s\n", mp->filename); 220 err = 1; 221 continue; 222 } 223 addend = (long)(((Rela *)reladdr)->r_addend); 224 reladdr += relocsize; 225 226 227 #ifdef KOBJ_DEBUG 228 if (kobj_debug & D_RELOCATIONS) { 229 Sym *symp; 230 symp = (Sym *) 231 (mp->symtbl+(stndx * mp->symhdr->sh_entsize)); 232 _kobj_printf(ops, "krtld:\t%s", 233 conv_reloc_SPARC_type(rtype)); 234 _kobj_printf(ops, "\t0x%8llx", off); 235 _kobj_printf(ops, " 0x%8llx", addend); 236 _kobj_printf(ops, " %s\n", 237 (const char *)mp->strings + symp->st_name); 238 } 239 #endif 240 241 if (rtype == R_SPARC_NONE) 242 continue; 243 244 if (!(mp->flags & KOBJ_EXEC)) 245 off += destination; 246 247 /* 248 * if R_SPARC_RELATIVE, simply add base addr 249 * to reloc location 250 */ 251 if (rtype == R_SPARC_RELATIVE) { 252 value = baseaddr; 253 } else { 254 /* 255 * get symbol table entry - if symbol is local 256 * value is base address of this object 257 */ 258 symref = (Sym *) 259 (mp->symtbl+(stndx * mp->symhdr->sh_entsize)); 260 if (ELF_ST_BIND(symref->st_info) == STB_LOCAL) { 261 /* *** this is different for .o and .so */ 262 value = symref->st_value; 263 } else { 264 /* 265 * It's global. Allow weak references. If 266 * the symbol is undefined, give TNF (the 267 * kernel probes facility) a chance to see 268 * if it's a probe site, and fix it up if so. 269 */ 270 if (symref->st_shndx == SHN_UNDEF && 271 sdt_reloc_resolve(mp, mp->strings + 272 symref->st_name, (uint32_t *)off, 273 roff + ((uintptr_t)baseaddr - 274 (uintptr_t)mp->text)) == 0) 275 continue; 276 277 if (symref->st_shndx == SHN_UNDEF && 278 tnf_reloc_resolve(mp->strings + 279 symref->st_name, &symref->st_value, 280 &addend, 281 off, 282 &probelist, 283 &taglist) != 0) { 284 if (ELF_ST_BIND(symref->st_info) 285 != STB_WEAK) { 286 _kobj_printf(ops, 287 "not found: %s\n", 288 mp->strings + 289 symref->st_name); 290 err = 1; 291 } 292 continue; 293 } else { /* symbol found - relocate */ 294 /* 295 * calculate location of definition 296 * - symbol value plus base address of 297 * containing shared object 298 */ 299 value = symref->st_value; 300 } /* end else symbol found */ 301 } 302 } /* end not R_SPARC_RELATIVE */ 303 304 value += addend; 305 if (IS_EXTOFFSET(rtype)) { 306 value += 307 (Word) ELF_R_TYPE_DATA(((Rela *)reladdr)->r_info); 308 } 309 310 /* 311 * calculate final value - 312 * if PC-relative, subtract ref addr 313 */ 314 if (IS_PC_RELATIVE(rtype)) { 315 if (mp->destination) 316 value -= (baseaddr + roff); 317 else 318 value -= off; 319 } 320 321 #ifdef KOBJ_DEBUG 322 if (kobj_debug & D_RELOCATIONS) { 323 _kobj_printf(ops, "krtld:\t\t\t\t0x%8llx", off); 324 _kobj_printf(ops, " 0x%8llx\n", value); 325 } 326 #endif 327 if (do_reloc(rtype, (unsigned char *)off, (Xword *)&value, 328 (const char *)mp->strings + symref->st_name, 329 mp->filename, 0) == 0) 330 err = 1; 331 } /* end of while loop */ 332 333 if (err) 334 return (-1); 335 336 if (tnf_splice_probes(mp->flags & KOBJ_PRIM, probelist, taglist)) 337 mp->flags |= KOBJ_TNF_PROBE; 338 339 return (0); 340 } 341 342 int 343 do_relocations(struct module *mp) 344 { 345 uint_t shn; 346 Shdr *shp, *rshp; 347 uint_t nreloc; 348 349 /* do the relocations */ 350 for (shn = 1; shn < mp->hdr.e_shnum; shn++) { 351 rshp = (Shdr *) 352 (mp->shdrs + shn * mp->hdr.e_shentsize); 353 if (rshp->sh_type == SHT_REL) { 354 _kobj_printf(ops, "%s can't process type SHT_REL\n", 355 mp->filename); 356 return (-1); 357 } 358 if (rshp->sh_type != SHT_RELA) 359 continue; 360 if (rshp->sh_link != mp->symtbl_section) { 361 _kobj_printf(ops, "%s reloc for non-default symtab\n", 362 mp->filename); 363 return (-1); 364 } 365 if (rshp->sh_info >= mp->hdr.e_shnum) { 366 _kobj_printf(ops, "do_relocations: %s ", mp->filename); 367 _kobj_printf(ops, " sh_info out of range %lld\n", shn); 368 goto bad; 369 } 370 nreloc = rshp->sh_size / rshp->sh_entsize; 371 372 /* get the section header that this reloc table refers to */ 373 shp = (Shdr *) 374 (mp->shdrs + rshp->sh_info * mp->hdr.e_shentsize); 375 /* 376 * Do not relocate any section that isn't loaded into memory. 377 * Most commonly this will skip over the .rela.stab* sections 378 */ 379 if (!(shp->sh_flags & SHF_ALLOC)) 380 continue; 381 #ifdef KOBJ_DEBUG 382 if (kobj_debug & D_RELOCATIONS) { 383 _kobj_printf(ops, "krtld: relocating: file=%s ", 384 mp->filename); 385 _kobj_printf(ops, " section=%d\n", shn); 386 } 387 #endif 388 if (do_relocate(mp, (char *)rshp->sh_addr, rshp->sh_type, 389 nreloc, rshp->sh_entsize, shp->sh_addr) < 0) { 390 _kobj_printf(ops, 391 "do_relocations: %s do_relocate failed\n", 392 mp->filename); 393 goto bad; 394 } 395 kobj_free((void *)rshp->sh_addr, rshp->sh_size); 396 rshp->sh_addr = 0; 397 } 398 mp->flags |= KOBJ_RELOCATED; 399 return (0); 400 bad: 401 kobj_free((void *)rshp->sh_addr, rshp->sh_size); 402 rshp->sh_addr = 0; 403 return (-1); 404 } 405