alpha_reloc.c revision 1.13
1 /* $NetBSD: alpha_reloc.c,v 1.13 2002/09/06 15:17:55 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 2001 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Jason R. Thorpe for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/types.h> 39 #include <sys/stat.h> 40 41 #include "rtld.h" 42 #include "debug.h" 43 44 #ifdef RTLD_DEBUG_ALPHA 45 #define adbg(x) if (dodebug) xprintf x 46 #else 47 #define adbg(x) /* nothing */ 48 #endif 49 50 void 51 _rtld_setup_pltgot(const Obj_Entry *obj) 52 { 53 uint32_t word0; 54 55 /* 56 * The PLTGOT on the Alpha looks like this: 57 * 58 * PLT HEADER 59 * . 60 * . 32 bytes 61 * . 62 * PLT ENTRY #0 63 * . 64 * . 12 bytes 65 * . 66 * PLT ENTRY #1 67 * . 68 * . 12 bytes 69 * . 70 * etc. 71 * 72 * The old-format entries look like (displacements filled in 73 * by the linker): 74 * 75 * ldah $28, 0($31) # 0x279f0000 76 * lda $28, 0($28) # 0x239c0000 77 * br $31, plt0 # 0xc3e00000 78 * 79 * The new-format entries look like: 80 * 81 * br $28, plt0 # 0xc3800000 82 * # 0x00000000 83 * # 0x00000000 84 * 85 * What we do is fetch the first PLT entry and check to 86 * see the first word of it matches the first word of the 87 * old format. If so, we use a binding routine that can 88 * handle the old format, otherwise we use a binding routine 89 * that handles the new format. 90 * 91 * Note that this is done on a per-object basis, we can mix 92 * and match shared objects build with both the old and new 93 * linker. 94 */ 95 word0 = *(uint32_t *)(((char *) obj->pltgot) + 32); 96 if ((word0 & 0xffff0000) == 0x279f0000) { 97 /* Old PLT entry format. */ 98 adbg(("ALPHA: object %p has old PLT format\n", obj)); 99 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start_old; 100 obj->pltgot[3] = (Elf_Addr) obj; 101 } else { 102 /* New PLT entry format. */ 103 adbg(("ALPHA: object %p has new PLT format\n", obj)); 104 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 105 obj->pltgot[3] = (Elf_Addr) obj; 106 } 107 108 __asm __volatile("imb"); 109 } 110 111 int 112 _rtld_relocate_nonplt_objects(obj, self, dodebug) 113 const Obj_Entry *obj; 114 bool self; 115 bool dodebug; 116 { 117 const Elf_Rela *rela; 118 119 for (rela = obj->rela; rela < obj->relalim; rela++) { 120 Elf_Addr *where; 121 const Elf_Sym *def; 122 const Obj_Entry *defobj; 123 Elf_Addr tmp; 124 unsigned long symnum; 125 126 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 127 symnum = ELF_R_SYM(rela->r_info); 128 129 switch (ELF_R_TYPE(rela->r_info)) { 130 case R_TYPE(NONE): 131 break; 132 133 case R_TYPE(REFQUAD): 134 def = _rtld_find_symdef(symnum, obj, &defobj, false); 135 if (def == NULL) 136 return -1; 137 138 tmp = (Elf_Addr)(defobj->relocbase + def->st_value) + 139 *where + rela->r_addend; 140 if (*where != tmp) 141 *where = tmp; 142 rdbg(dodebug, ("REFQUAD %s in %s --> %p in %s", 143 obj->strtab + obj->symtab[symnum].st_name, 144 obj->path, (void *)*where, defobj->path)); 145 break; 146 147 case R_TYPE(GLOB_DAT): 148 def = _rtld_find_symdef(symnum, obj, &defobj, false); 149 if (def == NULL) 150 return -1; 151 152 tmp = (Elf_Addr)(defobj->relocbase + def->st_value) + 153 rela->r_addend; 154 if (*where != tmp) 155 *where = tmp; 156 rdbg(dodebug, ("GLOB_DAT %s in %s --> %p in %s", 157 obj->strtab + obj->symtab[symnum].st_name, 158 obj->path, (void *)*where, defobj->path)); 159 break; 160 161 case R_TYPE(RELATIVE): 162 { 163 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 164 extern Elf_Addr _GOT_END_[]; 165 166 /* This is the ...iffy hueristic. */ 167 if (!self || 168 (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ || 169 (caddr_t)where >= (caddr_t)_GOT_END_) { 170 *where += (Elf_Addr)obj->relocbase; 171 rdbg(dodebug, ("RELATIVE in %s --> %p", 172 obj->path, (void *)*where)); 173 } else 174 rdbg(dodebug, ("RELATIVE in %s stays at %p", 175 obj->path, (void *)*where)); 176 break; 177 } 178 179 case R_TYPE(COPY): 180 /* 181 * These are deferred until all other relocations have 182 * been done. All we do here is make sure that the 183 * COPY relocation is not in a shared library. They 184 * are allowed only in executable files. 185 */ 186 if (obj->isdynamic) { 187 _rtld_error( 188 "%s: Unexpected R_COPY relocation in shared library", 189 obj->path); 190 return -1; 191 } 192 rdbg(dodebug, ("COPY (avoid in main)")); 193 break; 194 195 default: 196 rdbg(dodebug, ("sym = %lu, type = %lu, offset = %p, " 197 "addend = %p, contents = %p, symbol = %s", 198 symnum, (u_long)ELF_R_TYPE(rela->r_info), 199 (void *)rela->r_offset, (void *)rela->r_addend, 200 (void *)*where, 201 obj->strtab + obj->symtab[symnum].st_name)); 202 _rtld_error("%s: Unsupported relocation type %ld " 203 "in non-PLT relocations\n", 204 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 205 return -1; 206 } 207 } 208 return 0; 209 } 210 211 int 212 _rtld_relocate_plt_lazy(obj, dodebug) 213 const Obj_Entry *obj; 214 bool dodebug; 215 { 216 const Elf_Rela *rela; 217 218 if (!obj->isdynamic) 219 return 0; 220 221 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 222 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 223 224 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 225 226 /* Just relocate the GOT slots pointing into the PLT */ 227 *where += (Elf_Addr)obj->relocbase; 228 rdbg(dodebug, ("fixup !main in %s --> %p", obj->path, 229 (void *)*where)); 230 } 231 232 return 0; 233 } 234 235 int 236 _rtld_relocate_plt_object(obj, rela, addrp, dodebug) 237 const Obj_Entry *obj; 238 const Elf_Rela *rela; 239 caddr_t *addrp; 240 bool dodebug; 241 { 242 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 243 Elf_Addr new_value; 244 const Elf_Sym *def; 245 const Obj_Entry *defobj; 246 247 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 248 249 def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true); 250 if (def == NULL) 251 return -1; 252 253 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 254 rdbg(dodebug, ("bind now/fixup in %s --> old=%p new=%p", 255 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 256 if (*where != new_value) 257 *where = new_value; 258 259 *addrp = (caddr_t)new_value; 260 return 0; 261 } 262
Indexes created Tue Oct 14 21:09:58 GMT 2025