sysdeps/mips/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  MIPS version.
   2    Copyright (C) 1996-2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Kazumoto Kojima <kkojima@info.kanagawa-u.ac.jp>.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 /*  FIXME: Profiling of shared libraries is not implemented yet.  */
  22 #ifndef dl_machine_h
  23 #define dl_machine_h
  24
  25 #define ELF_MACHINE_NAME "MIPS"
  26
  27 #define ELF_MACHINE_NO_PLT
  28
  29 #include <entry.h>
  30
  31 #ifndef ENTRY_POINT
  32 #error ENTRY_POINT needs to be defined for MIPS.
  33 #endif
  34
  35 #include <sys/asm.h>
  36
  37 /* The offset of gp from GOT might be system-dependent.  It's set by
  38    ld.  The same value is also */
  39 #define OFFSET_GP_GOT 0x7ff0
  40
  41 #ifndef _RTLD_PROLOGUE
  42 # define _RTLD_PROLOGUE(entry)                                          \
  43         ".globl\t" __STRING(entry) "\n\t"                               \
  44         ".ent\t" __STRING(entry) "\n\t"                                 \
  45         ".type\t" __STRING(entry) ", @function\n"                       \
  46         __STRING(entry) ":\n\t"
  47 #endif
  48
  49 #ifndef _RTLD_EPILOGUE
  50 # define _RTLD_EPILOGUE(entry)                                          \
  51         ".end\t" __STRING(entry) "\n\t"                                 \
  52         ".size\t" __STRING(entry) ", . - " __STRING(entry) "\n\t"
  53 #endif
  54
  55 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.
  56    This makes no sense on MIPS but we have to define this to R_MIPS_REL32
  57    to avoid the asserts in dl-lookup.c from blowing.  */
  58 #define ELF_MACHINE_JMP_SLOT                    R_MIPS_REL32
  59 #define elf_machine_type_class(type)            ELF_RTYPE_CLASS_PLT
  60
  61 /* Translate a processor specific dynamic tag to the index
  62    in l_info array.  */
  63 #define DT_MIPS(x) (DT_MIPS_##x - DT_LOPROC + DT_NUM)
  64
  65 /* If there is a DT_MIPS_RLD_MAP entry in the dynamic section, fill it in
  66    with the run-time address of the r_debug structure  */
  67 #define ELF_MACHINE_DEBUG_SETUP(l,r) \
  68 do { if ((l)->l_info[DT_MIPS (RLD_MAP)]) \
  69        *(ElfW(Addr) *)((l)->l_info[DT_MIPS (RLD_MAP)]->d_un.d_ptr) = \
  70        (ElfW(Addr)) (r); \
  71    } while (0)
  72
  73 /* Return nonzero iff ELF header is compatible with the running host.  */
  74 static inline int __attribute_used__
  75 elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
  76 {
  77 #if _MIPS_SIM == _MIPS_SIM_ABI32 || _MIPS_SIM == _MIPS_SIM_NABI32
  78   /* Don't link o32 and n32 together.  */
  79   if (((ehdr->e_flags & EF_MIPS_ABI2) != 0)
  80       != (_MIPS_SIM != _MIPS_SIM_ABI32))
  81     return 0;
  82 #endif
  83
  84   switch (ehdr->e_machine)
  85     {
  86     case EM_MIPS:
  87     case EM_MIPS_RS3_LE:
  88       return 1;
  89     default:
  90       return 0;
  91     }
  92 }
  93
  94 static inline ElfW(Addr) *
  95 elf_mips_got_from_gpreg (ElfW(Addr) gpreg)
  96 {
  97   /* FIXME: the offset of gp from GOT may be system-dependent. */
  98   return (ElfW(Addr) *) (gpreg - OFFSET_GP_GOT);
  99 }
 100
 101 /* Return the link-time address of _DYNAMIC.  Conveniently, this is the
 102    first element of the GOT.  This must be inlined in a function which
 103    uses global data.  We assume its $gp points to the primary GOT.  */
 104 static inline ElfW(Addr)
 105 elf_machine_dynamic (void)
 106 {
 107   register ElfW(Addr) gp __asm__ ("$28");
 108   return *elf_mips_got_from_gpreg (gp);
 109 }
 110
 111 #define STRINGXP(X) __STRING(X)
 112 #define STRINGXV(X) STRINGV_(X)
 113 #define STRINGV_(...) # __VA_ARGS__
 114
 115 /* Return the run-time load address of the shared object.  */
 116 static inline ElfW(Addr)
 117 elf_machine_load_address (void)
 118 {
 119   ElfW(Addr) addr;
 120   asm ("        .set noreorder\n"
 121        "        " STRINGXP (PTR_LA) " %0, 0f\n"
 122        "        bltzal $0, 0f\n"
 123        "        nop\n"
 124        "0:      " STRINGXP (PTR_SUBU) " %0, $31, %0\n"
 125        "        .set reorder\n"
 126        :        "=r" (addr)
 127        :        /* No inputs */
 128        :        "$31");
 129   return addr;
 130 }
 131
 132 /* The MSB of got[1] of a gnu object is set to identify gnu objects.  */
 133 #if _MIPS_SIM == _MIPS_SIM_ABI64
 134 # define ELF_MIPS_GNU_GOT1_MASK 0x8000000000000000L
 135 #else
 136 # define ELF_MIPS_GNU_GOT1_MASK 0x80000000L
 137 #endif
 138
 139 /* We can't rely on elf_machine_got_rel because _dl_object_relocation_scope
 140    fiddles with global data.  */
 141 #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info)                     \
 142 do {                                                                    \
 143   struct link_map *map = &bootstrap_map;                                \
 144   ElfW(Sym) *sym;                                                       \
 145   ElfW(Addr) *got;                                                      \
 146   int i, n;                                                             \
 147                                                                         \
 148   got = (ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);                  \
 149                                                                         \
 150   if (__builtin_expect (map->l_addr == 0, 1))                           \
 151     break;                                                              \
 152                                                                         \
 153   /* got[0] is reserved. got[1] is also reserved for the dynamic object \
 154      generated by gnu ld. Skip these reserved entries from              \
 155      relocation.  */                                                    \
 156   i = (got[1] & ELF_MIPS_GNU_GOT1_MASK)? 2 : 1;                         \
 157   n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;                   \
 158                                                                         \
 159   /* Add the run-time displacement to all local got entries. */         \
 160   while (i < n)                                                         \
 161     got[i++] += map->l_addr;                                            \
 162                                                                         \
 163   /* Handle global got entries. */                                      \
 164   got += n;                                                             \
 165   sym = (ElfW(Sym) *) D_PTR(map, l_info[DT_SYMTAB])                     \
 166        + map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;                     \
 167   i = (map->l_info[DT_MIPS (SYMTABNO)]->d_un.d_val                      \
 168        - map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val);                    \
 169                                                                         \
 170   while (i--)                                                           \
 171     {                                                                   \
 172       if (sym->st_shndx == SHN_UNDEF || sym->st_shndx == SHN_COMMON)    \
 173         *got = map->l_addr + sym->st_value;                             \
 174       else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC                 \
 175                && *got != sym->st_value)                                \
 176         *got += map->l_addr;                                            \
 177       else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION)             \
 178         {                                                               \
 179           if (sym->st_other == 0)                                       \
 180             *got += map->l_addr;                                        \
 181         }                                                               \
 182       else                                                              \
 183         *got = map->l_addr + sym->st_value;                             \
 184                                                                         \
 185       got++;                                                            \
 186       sym++;                                                            \
 187     }                                                                   \
 188 } while(0)
 189
 190
 191 /* Get link map for callers object containing STUB_PC.  */
 192 static inline struct link_map *
 193 elf_machine_runtime_link_map (ElfW(Addr) gpreg, ElfW(Addr) stub_pc)
 194 {
 195   extern int _dl_mips_gnu_objects;
 196
 197   /* got[1] is reserved to keep its link map address for the shared
 198      object generated by the gnu linker.  If all are such objects, we
 199      can find the link map from current GPREG simply.  If not so, get
 200      the link map for caller's object containing STUB_PC.  */
 201
 202   if (_dl_mips_gnu_objects)
 203     {
 204       ElfW(Addr) *got = elf_mips_got_from_gpreg (gpreg);
 205       ElfW(Word) g1;
 206
 207       g1 = ((ElfW(Word) *) got)[1];
 208
 209       if ((g1 & ELF_MIPS_GNU_GOT1_MASK) != 0)
 210         {
 211           struct link_map *l =
 212             (struct link_map *) (g1 & ~ELF_MIPS_GNU_GOT1_MASK);
 213           ElfW(Addr) base, limit;
 214           const ElfW(Phdr) *p = l->l_phdr;
 215           ElfW(Half) this, nent = l->l_phnum;
 216
 217           /* For the common case of a stub being called from the containing
 218              object, STUB_PC will point to somewhere within the object that
 219              is described by the link map fetched via got[1].  Otherwise we
 220              have to scan all maps.  */
 221           for (this = 0; this < nent; this++)
 222             {
 223               if (p[this].p_type == PT_LOAD)
 224                 {
 225                   base = p[this].p_vaddr + l->l_addr;
 226                   limit = base + p[this].p_memsz;
 227                   if (stub_pc >= base && stub_pc < limit)
 228                     return l;
 229                 }
 230             }
 231         }
 232     }
 233
 234     struct link_map *l;
 235     Lmid_t nsid;
 236
 237     for (nsid = 0; nsid < DL_NNS; ++nsid)
 238       for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
 239         {
 240           ElfW(Addr) base, limit;
 241           const ElfW(Phdr) *p = l->l_phdr;
 242           ElfW(Half) this, nent = l->l_phnum;
 243
 244           for (this = 0; this < nent; ++this)
 245             {
 246               if (p[this].p_type == PT_LOAD)
 247                 {
 248                   base = p[this].p_vaddr + l->l_addr;
 249                   limit = base + p[this].p_memsz;
 250                   if (stub_pc >= base && stub_pc < limit)
 251                     return l;
 252                 }
 253             }
 254         }
 255
 256   _dl_signal_error (0, NULL, NULL, "cannot find runtime link map");
 257   return NULL;
 258 }
 259
 260 #if _MIPS_SIM == _MIPS_SIM_ABI32
 261 #define ELF_DL_FRAME_SIZE 40
 262
 263 #define ELF_DL_SAVE_ARG_REGS "\
 264         sw      $15, 36($29)\n                                                \
 265         sw      $4, 16($29)\n                                                 \
 266         sw      $5, 20($29)\n                                                 \
 267         sw      $6, 24($29)\n                                                 \
 268         sw      $7, 28($29)\n                                                 \
 269 "
 270
 271 #define ELF_DL_RESTORE_ARG_REGS "\
 272         lw      $31, 36($29)\n                                                \
 273         lw      $4, 16($29)\n                                                 \
 274         lw      $5, 20($29)\n                                                 \
 275         lw      $6, 24($29)\n                                                 \
 276         lw      $7, 28($29)\n                                                 \
 277 "
 278
 279 #define IFABIO32(X) X
 280
 281 #else /* _MIPS_SIM == _MIPS_SIM_NABI32 || _MIPS_SIM == _MIPS_SIM_ABI64 */
 282
 283 #define ELF_DL_FRAME_SIZE 80
 284
 285 #define ELF_DL_SAVE_ARG_REGS "\
 286         sd      $15, 72($29)\n                                                \
 287         sd      $4, 8($29)\n                                                  \
 288         sd      $5, 16($29)\n                                                 \
 289         sd      $6, 24($29)\n                                                 \
 290         sd      $7, 32($29)\n                                                 \
 291         sd      $8, 40($29)\n                                                 \
 292         sd      $9, 48($29)\n                                                 \
 293         sd      $10, 56($29)\n                                                \
 294         sd      $11, 64($29)\n                                                \
 295 "
 296
 297 #define ELF_DL_RESTORE_ARG_REGS "\
 298         ld      $31, 72($29)\n                                                \
 299         ld      $4, 8($29)\n                                                  \
 300         ld      $5, 16($29)\n                                                 \
 301         ld      $6, 24($29)\n                                                 \
 302         ld      $7, 32($29)\n                                                 \
 303         ld      $8, 40($29)\n                                                 \
 304         ld      $9, 48($29)\n                                                 \
 305         ld      $10, 56($29)\n                                                \
 306         ld      $11, 64($29)\n                                                \
 307 "
 308
 309 #define IFABIO32(X)
 310
 311 #endif
 312
 313 /* Define mips specific runtime resolver. The function __dl_runtime_resolve
 314    is called from assembler function _dl_runtime_resolve which converts
 315    special argument registers t7 ($15) and t8 ($24):
 316      t7  address to return to the caller of the function
 317      t8  index for this function symbol in .dynsym
 318    to usual c arguments.
 319
 320    Other architectures call fixup from dl-runtime.c in
 321    _dl_runtime_resolve.  MIPS instead calls __dl_runtime_resolve.  We
 322    have to use our own version because of the way the got section is
 323    treated on MIPS (we've also got ELF_MACHINE_PLT defined).  */
 324
 325 #define ELF_MACHINE_RUNTIME_TRAMPOLINE                                        \
 326 /* The flag _dl_mips_gnu_objects is set if all dynamic objects are            \
 327    generated by the gnu linker. */                                            \
 328 int _dl_mips_gnu_objects = 1;                                                 \
 329                                                                               \
 330 /* This is called from assembly stubs below which the compiler can't see.  */ \
 331 static ElfW(Addr)                                                             \
 332 __dl_runtime_resolve (ElfW(Word), ElfW(Word), ElfW(Addr), ElfW(Addr))         \
 333                   __attribute_used__;                                         \
 334                                                                               \
 335 static ElfW(Addr)                                                             \
 336 __dl_runtime_resolve (ElfW(Word) sym_index,                                   \
 337                       ElfW(Word) return_address,                              \
 338                       ElfW(Addr) old_gpreg,                                   \
 339                       ElfW(Addr) stub_pc)                                     \
 340 {                                                                             \
 341   struct link_map *l = elf_machine_runtime_link_map (old_gpreg, stub_pc);     \
 342   const ElfW(Sym) *const symtab                                               \
 343     = (const ElfW(Sym) *) D_PTR (l, l_info[DT_SYMTAB]);                       \
 344   const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);           \
 345   ElfW(Addr) *got                                                             \
 346     = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);                            \
 347   const ElfW(Word) local_gotno                                                \
 348     = (const ElfW(Word)) l->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;        \
 349   const ElfW(Word) gotsym                                                     \
 350     = (const ElfW(Word)) l->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;             \
 351   const ElfW(Sym) *sym = &symtab[sym_index];                                  \
 352   ElfW(Addr) value;                                                           \
 353                                                                               \
 354   /* FIXME: The symbol versioning stuff is not tested yet.  */                \
 355   if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)         \
 356     {                                                                         \
 357       switch (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL)                       \
 358         {                                                                     \
 359         default:                                                              \
 360           {                                                                   \
 361             const ElfW(Half) *vernum =                                        \
 362               (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);        \
 363             ElfW(Half) ndx = vernum[sym_index] & 0x7fff;                      \
 364             const struct r_found_version *version = &l->l_versions[ndx];      \
 365                                                                               \
 366             if (version->hash != 0)                                           \
 367               {                                                               \
 368                 value = _dl_lookup_symbol_x (strtab + sym->st_name, l,        \
 369                                              &sym, l->l_scope, version,       \
 370                                              ELF_RTYPE_CLASS_PLT, 0, 0);      \
 371                 break;                                                        \
 372               }                                                               \
 373             /* Fall through.  */                                              \
 374           }                                                                   \
 375         case 0:                                                               \
 376           value = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym,        \
 377                                        l->l_scope, 0, ELF_RTYPE_CLASS_PLT,    \
 378                                        DL_LOOKUP_ADD_DEPENDENCY, 0);          \
 379         }                                                                     \
 380                                                                               \
 381       /* Currently value contains the base load address of the object         \
 382          that defines sym.  Now add in the symbol offset.  */                 \
 383       value = (sym ? value + sym->st_value : 0);                              \
 384     }                                                                         \
 385   else                                                                        \
 386     /* We already found the symbol.  The module (and therefore its load       \
 387        address) is also known.  */                                            \
 388     value = l->l_addr + sym->st_value;                                        \
 389                                                                               \
 390   /* Apply the relocation with that value.  */                                \
 391   *(got + local_gotno + sym_index - gotsym) = value;                          \
 392                                                                               \
 393   return value;                                                               \
 394 }                                                                             \
 395                                                                               \
 396 asm ("\n                                                                      \
 397         .text\n                                                               \
 398         .align  2\n                                                           \
 399         .globl  _dl_runtime_resolve\n                                         \
 400         .type   _dl_runtime_resolve,@function\n                               \
 401         .ent    _dl_runtime_resolve\n                                         \
 402 _dl_runtime_resolve:\n                                                        \
 403         .frame  $29, " STRINGXP(ELF_DL_FRAME_SIZE) ", $31\n                   \
 404         .set noreorder\n                                                      \
 405         # Save GP.\n                                                          \
 406         move    $3, $28\n                                                     \
 407         # Save arguments and sp value in stack.\n                             \
 408         " STRINGXP(PTR_SUBIU) "  $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n       \
 409         # Modify t9 ($25) so as to point .cpload instruction.\n               \
 410         " IFABIO32(STRINGXP(PTR_ADDIU) "        $25, 12\n") "                 \
 411         # Compute GP.\n                                                       \
 412         " STRINGXP(SETUP_GP) "\n                                              \
 413         " STRINGXV(SETUP_GP64 (0, _dl_runtime_resolve)) "\n                   \
 414         .set reorder\n                                                        \
 415         # Save slot call pc.\n                                                \
 416         move    $2, $31\n                                                     \
 417         " IFABIO32(STRINGXP(CPRESTORE(32))) "\n                               \
 418         " ELF_DL_SAVE_ARG_REGS "                                              \
 419         move    $4, $24\n                                                     \
 420         move    $5, $15\n                                                     \
 421         move    $6, $3\n                                                      \
 422         move    $7, $2\n                                                      \
 423         jal     __dl_runtime_resolve\n                                        \
 424         " ELF_DL_RESTORE_ARG_REGS "                                           \
 425         " STRINGXP(RESTORE_GP64) "\n                                          \
 426         " STRINGXP(PTR_ADDIU) " $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n        \
 427         move    $25, $2\n                                                     \
 428         jr      $25\n                                                         \
 429         .end    _dl_runtime_resolve\n                                         \
 430         .previous\n                                                           \
 431 ");
 432
 433 /* Mask identifying addresses reserved for the user program,
 434    where the dynamic linker should not map anything.  */
 435 #define ELF_MACHINE_USER_ADDRESS_MASK   0x80000000UL
 436
 437
 438 /* Initial entry point code for the dynamic linker.
 439    The C function `_dl_start' is the real entry point;
 440    its return value is the user program's entry point.
 441    Note how we have to be careful about two things:
 442
 443    1) That we allocate a minimal stack of 24 bytes for
 444       every function call, the MIPS ABI states that even
 445       if all arguments are passed in registers the procedure
 446       called can use the 16 byte area pointed to by $sp
 447       when it is called to store away the arguments passed
 448       to it.
 449
 450    2) That under Linux the entry is named __start
 451       and not just plain _start.  */
 452
 453 #define RTLD_START asm (\
 454         ".text\n"\
 455         _RTLD_PROLOGUE(ENTRY_POINT) "\
 456         " STRINGXV(SETUP_GPX($25)) "\n\
 457         " STRINGXV(SETUP_GPX64($18,$25)) "\n\
 458         # i386 ABI book says that the first entry of GOT holds\n\
 459         # the address of the dynamic structure. Though MIPS ABI\n\
 460         # doesn't say nothing about this, I emulate this here.\n\
 461         " STRINGXP(PTR_LA) " $4, _DYNAMIC\n\
 462         # Subtract OFFSET_GP_GOT\n\
 463         " STRINGXP(PTR_S) " $4, -0x7ff0($28)\n\
 464         move $4, $29\n\
 465         " STRINGXP(PTR_SUBIU) " $29, 16\n\
 466         \n\
 467         " STRINGXP(PTR_LA) " $8, .Lcoff\n\
 468         bltzal $8, .Lcoff\n\
 469 .Lcoff: " STRINGXP(PTR_SUBU) " $8, $31, $8\n\
 470         \n\
 471         " STRINGXP(PTR_LA) " $25, _dl_start\n\
 472         " STRINGXP(PTR_ADDU) " $25, $8\n\
 473         jalr $25\n\
 474         \n\
 475         " STRINGXP(PTR_ADDIU) " $29, 16\n\
 476         # Get the value of label '_dl_start_user' in t9 ($25).\n\
 477         " STRINGXP(PTR_LA) " $25, _dl_start_user\n\
 478         .globl _dl_start_user\n\
 479         .type _dl_start_user,@function\n\
 480         .aent _dl_start_user\n\
 481 _dl_start_user:\n\
 482         " STRINGXP(SETUP_GP) "\n\
 483         " STRINGXV(SETUP_GP64($18,_dl_start_user)) "\n\
 484         move $16, $28\n\
 485         # Save the user entry point address in a saved register.\n\
 486         move $17, $2\n\
 487         # See if we were run as a command with the executable file\n\
 488         # name as an extra leading argument.\n\
 489         lw $2, _dl_skip_args\n\
 490         beq $2, $0, 1f\n\
 491         # Load the original argument count.\n\
 492         " STRINGXP(PTR_L) " $4, 0($29)\n\
 493         # Subtract _dl_skip_args from it.\n\
 494         subu $4, $2\n\
 495         # Adjust the stack pointer to skip _dl_skip_args words.\n\
 496         sll $2, " STRINGXP (PTRLOG) "\n\
 497         " STRINGXP(PTR_ADDU) " $29, $2\n\
 498         # Save back the modified argument count.\n\
 499         " STRINGXP(PTR_S) " $4, 0($29)\n\
 500 1:      # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
 501         " STRINGXP(PTR_L) " $4, _rtld_local\n\
 502         " STRINGXP(PTR_L) /* or lw???  fixme */ " $5, 0($29)\n\
 503         " STRINGXP(PTR_LA) " $6, " STRINGXP (PTRSIZE) "($29)\n\
 504         sll $7, $5, " STRINGXP (PTRLOG) "\n\
 505         " STRINGXP(PTR_ADDU) " $7, $7, $6\n\
 506         " STRINGXP(PTR_ADDU) " $7, $7, " STRINGXP (PTRSIZE) " \n\
 507         " STRINGXP(PTR_SUBIU) " $29, 32\n\
 508         " STRINGXP(SAVE_GP(16)) "\n\
 509         # Call the function to run the initializers.\n\
 510         jal _dl_init_internal\n\
 511         " STRINGXP(PTR_ADDIU)  " $29, 32\n\
 512         # Pass our finalizer function to the user in $2 as per ELF ABI.\n\
 513         " STRINGXP(PTR_LA) " $2, _dl_fini\n\
 514         # Jump to the user entry point.\n\
 515         move $25, $17\n\
 516         jr $25\n\t"\
 517         _RTLD_EPILOGUE(ENTRY_POINT)\
 518         ".previous"\
 519 );
 520
 521 /* The MIPS never uses Elfxx_Rela relocations.  */
 522 #define ELF_MACHINE_NO_RELA 1
 523
 524 #endif /* !dl_machine_h */
 525
 526 #ifdef RESOLVE
 527
 528 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
 529    MAP is the object containing the reloc.  */
 530
 531 static inline void
 532 #ifdef RTLD_BOOTSTRAP
 533   __attribute__ ((always_inline))
 534 #endif
 535 elf_machine_rel (struct link_map *map, const ElfW(Rel) *reloc,
 536                  const ElfW(Sym) *sym, const struct r_found_version *version,
 537                  void *const reloc_addr)
 538 {
 539   const unsigned long int r_type = ELFW(R_TYPE) (reloc->r_info);
 540
 541 #if !defined RTLD_BOOTSTRAP && !defined SHARED
 542   /* This is defined in rtld.c, but nowhere in the static libc.a;
 543      make the reference weak so static programs can still link.  This
 544      declaration cannot be done when compiling rtld.c (i.e.  #ifdef
 545      RTLD_BOOTSTRAP) because rtld.c contains the common defn for
 546      _dl_rtld_map, which is incompatible with a weak decl in the same
 547      file.  */
 548   weak_extern (GL(dl_rtld_map));
 549 #endif
 550
 551   switch (r_type)
 552     {
 553 #if _MIPS_SIM == _MIPS_SIM_ABI64
 554     case (R_MIPS_64 << 8) | R_MIPS_REL32:
 555 #else
 556     case R_MIPS_REL32:
 557 #endif
 558       {
 559         int symidx = ELFW(R_SYM) (reloc->r_info);
 560         ElfW(Addr) reloc_value;
 561
 562         /* Support relocations on mis-aligned offsets.  Should we ever
 563            implement RELA, this should be replaced with an assignment
 564            from reloc->r_addend.  */
 565         __builtin_memcpy (&reloc_value, reloc_addr, sizeof (reloc_value));
 566
 567         if (symidx)
 568           {
 569             const ElfW(Word) gotsym
 570               = (const ElfW(Word)) map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
 571
 572             if ((ElfW(Word))symidx < gotsym)
 573               {
 574                 /* This wouldn't work for a symbol imported from other
 575                    libraries for which there's no GOT entry, but MIPS
 576                    requires every symbol referenced in a dynamic
 577                    relocation to have a GOT entry in the primary GOT,
 578                    so we only get here for locally-defined symbols.
 579                    For section symbols, we should *NOT* be adding
 580                    sym->st_value (per the definition of the meaning of
 581                    S in reloc expressions in the ELF64 MIPS ABI),
 582                    since it should have already been added to
 583                    reloc_value by the linker, but older versions of
 584                    GNU ld didn't add it, and newer versions don't emit
 585                    useless relocations to section symbols any more, so
 586                    it is safe to keep on adding sym->st_value, even
 587                    though it's not ABI compliant.  Some day we should
 588                    bite the bullet and stop doing this.  */
 589 #ifndef RTLD_BOOTSTRAP
 590                 if (map != &GL(dl_rtld_map))
 591 #endif
 592                   reloc_value += sym->st_value + map->l_addr;
 593               }
 594             else
 595               {
 596 #ifndef RTLD_BOOTSTRAP
 597                 const ElfW(Addr) *got
 598                   = (const ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);
 599                 const ElfW(Word) local_gotno
 600                   = (const ElfW(Word))
 601                     map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
 602
 603                 reloc_value += got[symidx + local_gotno - gotsym];
 604 #endif
 605               }
 606           }
 607         else
 608 #ifndef RTLD_BOOTSTRAP
 609           if (map != &GL(dl_rtld_map))
 610 #endif
 611             reloc_value += map->l_addr;
 612
 613         __builtin_memcpy (reloc_addr, &reloc_value, sizeof (reloc_value));
 614       }
 615       break;
 616     case R_MIPS_NONE:           /* Alright, Wilbur.  */
 617       break;
 618 #if _MIPS_SIM == _MIPS_SIM_ABI64
 619     case R_MIPS_64:
 620       /* For full compliance with the ELF64 ABI, one must precede the
 621          _REL32/_64 pair of relocations with a _64 relocation, such
 622          that the in-place addend is read as a 64-bit value.  IRIX
 623          didn't pick up on this requirement, so we treat the
 624          _REL32/_64 relocation as a 64-bit relocation even if it's by
 625          itself.  For ABI compliance, we ignore such _64 dummy
 626          relocations.  For RELA, this may be simply removed, since
 627          it's totally unnecessary.  */
 628       if (ELFW(R_SYM) (reloc->r_info) == 0)
 629         break;
 630       /* Fall through.  */
 631 #endif
 632     default:
 633       _dl_reloc_bad_type (map, r_type, 0);
 634       break;
 635     }
 636 }
 637
 638 static inline void
 639 elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
 640                           void *const reloc_addr)
 641 {
 642   /* XXX Nothing to do.  There is no relative relocation, right?  */
 643 }
 644
 645 static inline void
 646 elf_machine_lazy_rel (struct link_map *map,
 647                       ElfW(Addr) l_addr, const ElfW(Rel) *reloc)
 648 {
 649   /* Do nothing.  */
 650 }
 651
 652 #ifndef RTLD_BOOTSTRAP
 653 /* Relocate GOT. */
 654 static inline void
 655 elf_machine_got_rel (struct link_map *map, int lazy)
 656 {
 657   ElfW(Addr) *got;
 658   ElfW(Sym) *sym;
 659   const ElfW(Half) *vernum;
 660   int i, n, symidx;
 661
 662 #define RESOLVE_GOTSYM(sym,vernum,sym_index)                              \
 663     ({                                                                    \
 664       const ElfW(Sym) *ref = sym;                                         \
 665       const struct r_found_version *version                               \
 666         = vernum ? &map->l_versions[vernum[sym_index] & 0x7fff] : NULL;   \
 667       ElfW(Addr) value;                                                   \
 668       value = RESOLVE (&ref, version, R_MIPS_REL32);                      \
 669       (ref)? value + ref->st_value: 0;                                    \
 670     })
 671
 672   if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
 673     vernum = (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
 674   else
 675     vernum = NULL;
 676
 677   got = (ElfW(Addr) *) D_PTR (map, l_info[DT_PLTGOT]);
 678
 679   n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
 680   /* The dynamic linker's local got entries have already been relocated.  */
 681   if (map != &GL(dl_rtld_map))
 682     {
 683       /* got[0] is reserved. got[1] is also reserved for the dynamic object
 684          generated by gnu ld. Skip these reserved entries from relocation.  */
 685       i = (got[1] & ELF_MIPS_GNU_GOT1_MASK)? 2 : 1;
 686
 687       /* Add the run-time displacement to all local got entries if
 688          needed.  */
 689       if (__builtin_expect (map->l_addr != 0, 0))
 690         {
 691           while (i < n)
 692             got[i++] += map->l_addr;
 693         }
 694     }
 695
 696   /* Handle global got entries. */
 697   got += n;
 698   /* Keep track of the symbol index.  */
 699   symidx = map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
 700   sym = (ElfW(Sym) *) D_PTR (map, l_info[DT_SYMTAB]) + symidx;
 701   i = (map->l_info[DT_MIPS (SYMTABNO)]->d_un.d_val
 702        - map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val);
 703
 704   /* This loop doesn't handle Quickstart.  */
 705   while (i--)
 706     {
 707       if (sym->st_shndx == SHN_UNDEF)
 708         {
 709           if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC
 710               && sym->st_value && lazy)
 711             *got = sym->st_value + map->l_addr;
 712           else
 713             *got = RESOLVE_GOTSYM (sym, vernum, symidx);
 714         }
 715       else if (sym->st_shndx == SHN_COMMON)
 716         *got = RESOLVE_GOTSYM (sym, vernum, symidx);
 717       else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC
 718                && *got != sym->st_value
 719                && lazy)
 720         *got += map->l_addr;
 721       else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION)
 722         {
 723           if (sym->st_other == 0)
 724             *got += map->l_addr;
 725         }
 726       else
 727         *got = RESOLVE_GOTSYM (sym, vernum, symidx);
 728
 729       ++got;
 730       ++sym;
 731       ++symidx;
 732     }
 733
 734 #undef RESOLVE_GOTSYM
 735 }
 736 #endif
 737
 738 /* Set up the loaded object described by L so its stub function
 739    will jump to the on-demand fixup code __dl_runtime_resolve.  */
 740
 741 static inline int
 742 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
 743 {
 744 # ifndef RTLD_BOOTSTRAP
 745   ElfW(Addr) *got;
 746   extern void _dl_runtime_resolve (ElfW(Word));
 747   extern int _dl_mips_gnu_objects;
 748
 749   if (lazy)
 750     {
 751       /* The GOT entries for functions have not yet been filled in.
 752          Their initial contents will arrange when called to put an
 753          offset into the .dynsym section in t8, the return address
 754          in t7 and then jump to _GLOBAL_OFFSET_TABLE[0].  */
 755       got = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
 756
 757       /* This function will get called to fix up the GOT entry indicated by
 758          the register t8, and then jump to the resolved address.  */
 759       got[0] = (ElfW(Addr)) &_dl_runtime_resolve;
 760
 761       /* Store l to _GLOBAL_OFFSET_TABLE[1] for gnu object. The MSB
 762          of got[1] of a gnu object is set to identify gnu objects.
 763          Where we can store l for non gnu objects? XXX  */
 764       if ((got[1] & ELF_MIPS_GNU_GOT1_MASK) != 0)
 765         got[1] = ((ElfW(Addr)) l | ELF_MIPS_GNU_GOT1_MASK);
 766       else
 767         _dl_mips_gnu_objects = 0;
 768     }
 769
 770   /* Relocate global offset table.  */
 771   elf_machine_got_rel (l, lazy);
 772
 773 # endif
 774   return lazy;
 775 }
 776
 777 #endif /* RESOLVE */