ldso/ldso/microblaze/elfinterp.c

   1 /* microblaze ELF shared library loader suppport
   2  *
   3  * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
   4  *                              David Engel, Hongjiu Lu and Mitch D'Souza
   5  * Copyright (C) 2001-2004 Erik Andersen
   6  *
   7  * All rights reserved.
   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. The name of the above contributors may not be
  15  *    used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include "ldso.h"
  32
  33 /* Program to load an ELF binary on a linux system, and run it.
  34    References to symbols in sharable libraries can be resolved by either
  35    an ELF sharable library or a linux style of shared library. */
  36
  37 extern int _dl_linux_resolve(void);
  38
  39 unsigned long
  40 _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
  41 {
  42         ELF_RELOC *this_reloc;
  43         char *strtab;
  44         ElfW(Sym) *symtab;
  45         int symtab_index;
  46         char *rel_addr;
  47         char *new_addr;
  48         char **got_addr;
  49         ElfW(Addr) instr_addr;
  50         char *symname;
  51
  52         rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
  53         this_reloc = (ELF_RELOC *)(rel_addr + reloc_entry);
  54         symtab_index = ELF_R_SYM(this_reloc->r_info);
  55
  56         symtab = (ElfW(Sym) *)tpnt->dynamic_info[DT_SYMTAB];
  57         strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
  58         symname = strtab + symtab[symtab_index].st_name;
  59
  60         /* Address of the jump instruction to fix up. */
  61         instr_addr = (this_reloc->r_offset + tpnt->loadaddr);
  62         got_addr = (char **)instr_addr;
  63
  64         /* Get the address of the GOT entry. */
  65         new_addr = _dl_find_hash(symname, &_dl_loaded_modules->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
  66         if (unlikely(!new_addr)) {
  67                 _dl_dprintf(2, "%s: Can't resolve symbol '%s'\n", _dl_progname, symname);
  68                 _dl_exit(1);
  69         }
  70
  71 #if defined (__SUPPORT_LD_DEBUG__)
  72         if ((unsigned long)got_addr < 0x40000000) {
  73                 if (_dl_debug_bindings) {
  74                         _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
  75                         if (_dl_debug_detail)
  76                                 _dl_dprintf(_dl_debug_file,
  77                                             "\tpatched: %x ==> %x @ %x\n",
  78                                             *got_addr, new_addr, got_addr);
  79                 }
  80         }
  81         if (!_dl_debug_nofixups)
  82 #endif
  83                 *got_addr = new_addr;
  84
  85         return (unsigned long)new_addr;
  86 }
  87
  88 static int
  89 _dl_parse(struct elf_resolve *tpnt, struct r_scope_elem *scope,
  90           unsigned long rel_addr, unsigned long rel_size,
  91           int (*reloc_fnc)(struct elf_resolve *tpnt, struct r_scope_elem *scope,
  92                            ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab))
  93 {
  94         unsigned int i;
  95         char *strtab;
  96         ElfW(Sym) *symtab;
  97         ELF_RELOC *rpnt;
  98         int symtab_index;
  99
 100         /* Parse the relocation information. */
 101         rpnt = (ELF_RELOC *)rel_addr;
 102         rel_size /= sizeof(ELF_RELOC);
 103
 104         symtab = (ElfW(Sym) *)tpnt->dynamic_info[DT_SYMTAB];
 105         strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
 106
 107         for (i = 0; i < rel_size; i++, rpnt++) {
 108                 int res;
 109
 110                 symtab_index = ELF_R_SYM(rpnt->r_info);
 111
 112                 debug_sym(symtab, strtab, symtab_index);
 113                 debug_reloc(symtab, strtab, rpnt);
 114
 115                 res = reloc_fnc(tpnt, scope, rpnt, symtab, strtab);
 116
 117                 if (res == 0)
 118                         continue;
 119
 120                 _dl_dprintf(2, "\n%s: ", _dl_progname);
 121
 122                 if (symtab_index)
 123                         _dl_dprintf(2, "symbol '%s': ",
 124                                     strtab + symtab[symtab_index].st_name);
 125
 126                 if (unlikely(res < 0)) {
 127                         int reloc_type = ELF_R_TYPE(rpnt->r_info);
 128                         _dl_dprintf(2, "can't handle reloc type "
 129                                     "%x\n", reloc_type);
 130                         _dl_exit(-res);
 131                 } else if (unlikely(res > 0)) {
 132                         _dl_dprintf(2, "can't resolve symbol\n");
 133                         return res;
 134                 }
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int
 141 _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 142              ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
 143 {
 144         int reloc_type;
 145         int symtab_index;
 146         char *symname;
 147 #if defined USE_TLS && USE_TLS
 148         struct elf_resolve *tls_tpnt;
 149 #endif
 150         struct symbol_ref sym_ref;
 151         ElfW(Addr) *reloc_addr;
 152         ElfW(Addr) symbol_addr;
 153 #if defined (__SUPPORT_LD_DEBUG__)
 154         ElfW(Addr) old_val;
 155 #endif
 156
 157         reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + (unsigned long)rpnt->r_offset);
 158         reloc_type = ELF_R_TYPE(rpnt->r_info);
 159         symtab_index = ELF_R_SYM(rpnt->r_info);
 160         sym_ref.sym = &symtab[symtab_index];
 161         sym_ref.tpnt = NULL;
 162         symbol_addr = 0;
 163         symname = strtab + sym_ref.sym->st_name;
 164
 165         if (symtab_index) {
 166                 symbol_addr = (ElfW(Addr))_dl_find_hash(symname, scope, tpnt,
 167                                 elf_machine_type_class(reloc_type), &sym_ref);
 168                 /*
 169                  * We want to allow undefined references to weak symbols - this
 170                  * might have been intentional.  We should not be linking local
 171                  * symbols here, so all bases should be covered.
 172                  */
 173                 if (unlikely(!symbol_addr && (ELF_ST_TYPE(sym_ref.sym->st_info) != STT_TLS)
 174                                         && (ELF_ST_BIND(sym_ref.sym->st_info) != STB_WEAK))) {
 175                         /* This may be non-fatal if called from dlopen. */
 176                         return 1;
 177                 }
 178 #if defined USE_TLS && USE_TLS
 179                 tls_tpnt = sym_ref.tpnt;
 180 #endif
 181         } else {
 182                 /* Relocs against STN_UNDEF are usually treated as using a
 183                  * symbol value of zero, and using the module containing the
 184                  * reloc itself. */
 185                 symbol_addr = sym_ref.sym->st_value;
 186 #if defined USE_TLS && USE_TLS
 187                 tls_tpnt = tpnt;
 188 #endif
 189         }
 190
 191
 192 #if defined (__SUPPORT_LD_DEBUG__)
 193         if (reloc_addr) {
 194                 old_val = *reloc_addr;
 195         } else {
 196                 old_val = 0;
 197         }
 198 #endif
 199
 200         switch (reloc_type) {
 201                 case R_MICROBLAZE_NONE:
 202                 case R_MICROBLAZE_64_NONE:
 203                         break;
 204                 case R_MICROBLAZE_64:
 205                         *reloc_addr = symbol_addr + rpnt->r_addend;
 206                         break;
 207                 case R_MICROBLAZE_32:
 208                 case R_MICROBLAZE_32_LO:
 209                         *reloc_addr = symbol_addr + rpnt->r_addend;
 210                         break;
 211                 case R_MICROBLAZE_32_PCREL:
 212                 case R_MICROBLAZE_32_PCREL_LO:
 213                 case R_MICROBLAZE_64_PCREL:
 214                 case R_MICROBLAZE_SRO32:
 215                 case R_MICROBLAZE_SRW32:
 216                         *reloc_addr = symbol_addr + rpnt->r_addend;
 217                         break;
 218                 case R_MICROBLAZE_GLOB_DAT:
 219                 case R_MICROBLAZE_JUMP_SLOT:
 220                         *reloc_addr = symbol_addr + rpnt->r_addend;
 221                         break;
 222                 case R_MICROBLAZE_REL:
 223                         *reloc_addr = (unsigned long)tpnt->loadaddr + rpnt->r_addend;
 224                         break;
 225 #if defined USE_TLS && USE_TLS
 226                 case R_MICROBLAZE_TLSDTPMOD32:
 227                         *reloc_addr = tls_tpnt->l_tls_modid;
 228                         break;
 229                 case R_MICROBLAZE_TLSDTPREL32:
 230                         *reloc_addr = symbol_addr;
 231                         break;
 232                 case R_MICROBLAZE_TLSTPREL32:
 233                         CHECK_STATIC_TLS ((struct link_map *) tls_tpnt);
 234                         *reloc_addr = tls_tpnt->l_tls_offset + symbol_addr + rpnt->r_addend;
 235                         break;
 236 #endif
 237                 case R_MICROBLAZE_COPY:
 238                         if (symbol_addr) {
 239 #if defined (__SUPPORT_LD_DEBUG__)
 240                                 if (_dl_debug_move)
 241                                         _dl_dprintf(_dl_debug_file,
 242                                                     "\t%s move %d bytes from %x to %x\n",
 243                                                     symname, sym_ref.sym->st_size,
 244                                                     symbol_addr, reloc_addr);
 245 #endif
 246                                 _dl_memcpy((char *)reloc_addr,
 247                                            (char *)symbol_addr,
 248                                            sym_ref.sym->st_size);
 249                         }
 250 #if defined (__SUPPORT_LD_DEBUG__)
 251                         else
 252                                 _dl_dprintf(_dl_debug_file, "no symbol_addr to copy !?\n");
 253 #endif
 254                         break;
 255                 default:
 256                         return -1;      /* Calls _dl_exit(1). */
 257         }
 258
 259 #if defined (__SUPPORT_LD_DEBUG__)
 260         if (_dl_debug_reloc && _dl_debug_detail)
 261                 _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
 262                             old_val, *reloc_addr, reloc_addr);
 263 #endif
 264
 265         return 0;
 266 }
 267
 268 static int
 269 _dl_do_lazy_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
 270                   ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
 271 {
 272         int reloc_type;
 273         ElfW(Addr) *reloc_addr;
 274 #if defined (__SUPPORT_LD_DEBUG__)
 275         ElfW(Addr) old_val;
 276 #endif
 277
 278         (void)scope;
 279         (void)strtab;
 280
 281         reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + rpnt->r_offset);
 282         reloc_type = ELF_R_TYPE(rpnt->r_info);
 283
 284 #if defined (__SUPPORT_LD_DEBUG__)
 285         old_val = *reloc_addr;
 286 #endif
 287
 288         switch (reloc_type) {
 289                 case R_MICROBLAZE_NONE:
 290                         break;
 291                 case R_MICROBLAZE_JUMP_SLOT:
 292                         *reloc_addr += (unsigned long)tpnt->loadaddr;
 293                         break;
 294                 default:
 295                         _dl_exit(1);
 296         }
 297
 298 #if defined (__SUPPORT_LD_DEBUG__)
 299         if (_dl_debug_reloc && _dl_debug_detail)
 300                 _dl_dprintf(_dl_debug_file, "\tpatched_lazy: %x ==> %x @ %x\n",
 301                             old_val, *reloc_addr, reloc_addr);
 302 #endif
 303
 304         return 0;
 305 }
 306
 307 void
 308 _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
 309         unsigned long rel_addr, unsigned long rel_size)
 310 {
 311         (void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
 312 }
 313
 314 int
 315 _dl_parse_relocation_information(struct dyn_elf *rpnt,
 316         struct r_scope_elem *scope, unsigned long rel_addr, unsigned long rel_size)
 317 {
 318         return _dl_parse(rpnt->dyn, scope, rel_addr, rel_size, _dl_do_reloc);
 319 }