sysdeps/ia64/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  IA-64 version.
   2    Copyright (C) 1995-1997, 2000-2006, 2011 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef dl_machine_h
  21 #define dl_machine_h 1
  22
  23 #define ELF_MACHINE_NAME "ia64"
  24
  25 #include <assert.h>
  26 #include <string.h>
  27 #include <link.h>
  28 #include <errno.h>
  29 #include <dl-fptr.h>
  30 #include <tls.h>
  31
  32 /* Translate a processor specific dynamic tag to the index
  33    in l_info array.  */
  34 #define DT_IA_64(x) (DT_IA_64_##x - DT_LOPROC + DT_NUM)
  35
  36 static inline void __attribute__ ((always_inline))
  37 __ia64_init_bootstrap_fdesc_table (struct link_map *map)
  38 {
  39   Elf64_Addr *boot_table;
  40
  41   /* careful: this will be called before got has been relocated... */
  42   asm (";; addl %0 = @gprel (_dl_boot_fptr_table), gp" : "=r"(boot_table));
  43
  44   map->l_mach.fptr_table_len = ELF_MACHINE_BOOT_FPTR_TABLE_LEN;
  45   map->l_mach.fptr_table = boot_table;
  46 }
  47
  48 #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info)             \
  49         __ia64_init_bootstrap_fdesc_table (&bootstrap_map);
  50
  51 /* Return nonzero iff ELF header is compatible with the running host.  */
  52 static inline int __attribute__ ((unused))
  53 elf_machine_matches_host (const Elf64_Ehdr *ehdr)
  54 {
  55   return ehdr->e_machine == EM_IA_64;
  56 }
  57
  58
  59 /* Return the link-time address of _DYNAMIC.  */
  60 static inline Elf64_Addr __attribute__ ((unused, const))
  61 elf_machine_dynamic (void)
  62 {
  63   Elf64_Addr *p;
  64
  65   __asm__ (
  66         ".section .sdata\n"
  67         "       .type __dynamic_ltv#, @object\n"
  68         "       .size __dynamic_ltv#, 8\n"
  69         "__dynamic_ltv:\n"
  70         "       data8   @ltv(_DYNAMIC#)\n"
  71         ".previous\n"
  72         "       addl    %0 = @gprel(__dynamic_ltv#), gp ;;"
  73         : "=r" (p));
  74
  75   return *p;
  76 }
  77
  78
  79 /* Return the run-time load address of the shared object.  */
  80 static inline Elf64_Addr __attribute__ ((unused))
  81 elf_machine_load_address (void)
  82 {
  83   Elf64_Addr ip;
  84   int *p;
  85
  86   __asm__ (
  87         "1:     mov %0 = ip\n"
  88         ".section .sdata\n"
  89         "2:     data4   @ltv(1b)\n"
  90         "       .align 8\n"
  91         ".previous\n"
  92         "       addl    %1 = @gprel(2b), gp ;;"
  93         : "=r" (ip), "=r" (p));
  94
  95   return ip - (Elf64_Addr) *p;
  96 }
  97
  98 /* Set up the loaded object described by L so its unrelocated PLT
  99    entries will jump to the on-demand fixup code in dl-runtime.c.  */
 100
 101 static inline int __attribute__ ((unused, always_inline))
 102 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
 103 {
 104   extern void _dl_runtime_resolve (void);
 105   extern void _dl_runtime_profile (void);
 106
 107   if (lazy)
 108     {
 109       register Elf64_Addr gp __asm__ ("gp");
 110       Elf64_Addr *reserve, doit;
 111
 112       /*
 113        * Careful with the typecast here or it will try to add l-l_addr
 114        * pointer elements
 115        */
 116       reserve = ((Elf64_Addr *)
 117                  (l->l_info[DT_IA_64 (PLT_RESERVE)]->d_un.d_ptr + l->l_addr));
 118       /* Identify this shared object.  */
 119       reserve[0] = (Elf64_Addr) l;
 120
 121       /* This function will be called to perform the relocation.  */
 122       if (!profile)
 123         doit = (Elf64_Addr) ((struct fdesc *) &_dl_runtime_resolve)->ip;
 124       else
 125         {
 126           if (GLRO(dl_profile) != NULL
 127               && _dl_name_match_p (GLRO(dl_profile), l))
 128             {
 129               /* This is the object we are looking for.  Say that we really
 130                  want profiling and the timers are started.  */
 131               GL(dl_profile_map) = l;
 132             }
 133           doit = (Elf64_Addr) ((struct fdesc *) &_dl_runtime_profile)->ip;
 134         }
 135
 136       reserve[1] = doit;
 137       reserve[2] = gp;
 138     }
 139
 140   return lazy;
 141 }
 142
 143 /* Names of the architecture-specific auditing callback functions.  */
 144 #define ARCH_LA_PLTENTER ia64_gnu_pltenter
 145 #define ARCH_LA_PLTEXIT ia64_gnu_pltexit
 146
 147 /* Undo the adds out0 = 16, sp below to get at the value we want in
 148    __libc_stack_end.  */
 149 #define DL_STACK_END(cookie) \
 150   ((void *) (((long) (cookie)) - 16))
 151
 152 /* Initial entry point code for the dynamic linker.
 153    The C function `_dl_start' is the real entry point;
 154    its return value is the user program's entry point.  */
 155
 156 #define RTLD_START asm (                                                      \
 157 ".text\n"                                                                     \
 158 "       .global _start#\n"                                                    \
 159 "       .proc _start#\n"                                                      \
 160 "_start:\n"                                                                   \
 161 "0:     { .mii\n"                                                             \
 162 "         .prologue\n"                                                        \
 163 "         .save rp, r0\n"                                                     \
 164 "         .body\n"                                                            \
 165 "         .prologue\n"                                                        \
 166 "         .save ar.pfs, r32\n"                                                \
 167 "         alloc loc0 = ar.pfs, 0, 3, 4, 0\n"                                  \
 168 "         .body\n"                                                            \
 169 "         mov r2 = ip\n"                                                      \
 170 "         addl r3 = @gprel(0b), r0\n"                                         \
 171 "         ;;\n"                                                               \
 172 "       }\n"                                                                  \
 173 "       { .mlx\n"                                                             \
 174 "         /* Calculate the GP, and save a copy in loc1.  */\n"                \
 175 "         sub gp = r2, r3\n"                                                  \
 176 "         movl r8 = 0x9804c0270033f\n"                                        \
 177 "         ;;\n"                                                               \
 178 "       }\n"                                                                  \
 179 "       { .mii\n"                                                             \
 180 "         mov ar.fpsr = r8\n"                                                 \
 181 "         sub loc1 = r2, r3\n"                                                \
 182 "         /* _dl_start wants a pointer to the pointer to the arg block and\n" \
 183 "            the arg block starts with an integer, thus the magic 16. */\n"   \
 184 "         adds out0 = 16, sp\n"                                               \
 185 "       }\n"                                                                  \
 186 "       { .bbb\n"                                                             \
 187 "         br.call.sptk.many b0 = _dl_start#\n"                                \
 188 "         ;;\n"                                                               \
 189 "       }\n"                                                                  \
 190 "       .endp _start#\n"                                                      \
 191 "       /* FALLTHRU */\n"                                                     \
 192 "       .global _dl_start_user#\n"                                            \
 193 "       .proc _dl_start_user#\n"                                              \
 194 "_dl_start_user:\n"                                                           \
 195 "        .prologue\n"                                                         \
 196 "        .save rp, r0\n"                                                      \
 197 "         .body\n"                                                            \
 198 "        .prologue\n"                                                         \
 199 "        .save ar.pfs, r32\n"                                                 \
 200 "        .body\n"                                                             \
 201 "       { .mii\n"                                                             \
 202 "         addl r3 = @gprel(_dl_skip_args), gp\n"                              \
 203 "         adds r11 = 24, sp     /* Load the address of argv. */\n"            \
 204 "         /* Save the pointer to the user entry point fptr in loc2.  */\n"    \
 205 "         mov loc2 = ret0\n"                                                  \
 206 "         ;;\n"                                                               \
 207 "       }\n"                                                                  \
 208 "       { .mii\n"                                                             \
 209 "         ld4 r3 = [r3]\n"                                                    \
 210 "         adds r10 = 16, sp     /* Load the address of argc. */\n"            \
 211 "         mov out2 = r11\n"                                                   \
 212 "         ;;\n"                                                               \
 213 "         /* See if we were run as a command with the executable file\n"      \
 214 "            name as an extra leading argument.  If so, adjust the argv\n"    \
 215 "            pointer to skip _dl_skip_args words.\n"                          \
 216 "            Note that _dl_skip_args is an integer, not a long - Jes\n"       \
 217 "\n"                                                                          \
 218 "            The stack pointer has to be 16 byte aligned. We cannot simply\n" \
 219 "            addjust the stack pointer. We have to move the whole argv and\n" \
 220 "            envp and adjust _dl_argv by _dl_skip_args.  H.J.  */\n"          \
 221 "       }\n"                                                                  \
 222 "       { .mib\n"                                                             \
 223 "         ld8 out1 = [r10]      /* is argc actually stored as a long\n"       \
 224 "                                  or as an int? */\n"                        \
 225 "         addl r2 = @ltoff(_dl_argv), gp\n"                                   \
 226 "         ;;\n"                                                               \
 227 "       }\n"                                                                  \
 228 "       { .mmi\n"                                                             \
 229 "         ld8 r2 = [r2]         /* Get the address of _dl_argv. */\n"         \
 230 "         sub out1 = out1, r3   /* Get the new argc. */\n"                    \
 231 "         shladd r3 = r3, 3, r0\n"                                            \
 232 "         ;;\n"                                                               \
 233 "       }\n"                                                                  \
 234 "       {\n"                                                                  \
 235 "         .mib\n"                                                             \
 236 "         ld8 r17 = [r2]        /* Get _dl_argv. */\n"                        \
 237 "         add r15 = r11, r3     /* The address of the argv we move */\n"      \
 238 "         ;;\n"                                                               \
 239 "       }\n"                                                                  \
 240 "       /* ??? Could probably merge these two loops into 3 bundles.\n"        \
 241 "          using predication to control which set of copies we're on.  */\n"  \
 242 "1:     /* Copy argv. */\n"                                                   \
 243 "       { .mfi\n"                                                             \
 244 "         ld8 r16 = [r15], 8    /* Load the value in the old argv. */\n"      \
 245 "         ;;\n"                                                               \
 246 "       }\n"                                                                  \
 247 "       { .mib\n"                                                             \
 248 "         st8 [r11] = r16, 8    /* Store it in the new argv. */\n"            \
 249 "         cmp.ne p6, p7 = 0, r16\n"                                           \
 250 "(p6)     br.cond.dptk.few 1b\n"                                              \
 251 "         ;;\n"                                                               \
 252 "       }\n"                                                                  \
 253 "       { .mmi\n"                                                             \
 254 "         mov out3 = r11\n"                                                   \
 255 "         sub r17 = r17, r3     /* Substract _dl_skip_args. */\n"             \
 256 "         addl out0 = @gprel(_rtld_local), gp\n"                              \
 257 "       }\n"                                                                  \
 258 "1:     /* Copy env. */\n"                                                    \
 259 "       { .mfi\n"                                                             \
 260 "         ld8 r16 = [r15], 8    /* Load the value in the old env. */\n"       \
 261 "         ;;\n"                                                               \
 262 "       }\n"                                                                  \
 263 "       { .mib\n"                                                             \
 264 "         st8 [r11] = r16, 8    /* Store it in the new env. */\n"             \
 265 "         cmp.ne p6, p7 = 0, r16\n"                                           \
 266 "(p6)     br.cond.dptk.few 1b\n"                                              \
 267 "         ;;\n"                                                               \
 268 "       }\n"                                                                  \
 269 "       { .mmb\n"                                                             \
 270 "         st8 [r10] = out1              /* Record the new argc. */\n"         \
 271 "         ld8 out0 = [out0]             /* get the linkmap */\n"              \
 272 "       }\n"                                                                  \
 273 "       { .mmb\n"                                                             \
 274 "         st8 [r2] = r17                /* Load the new _dl_argv. */\n"       \
 275 "         br.call.sptk.many b0 = _dl_init_internal#\n"                        \
 276 "         ;;\n"                                                               \
 277 "       }\n"                                                                  \
 278 "       /* Pass our finalizer function to the user,\n"                        \
 279 "          and jump to the user's entry point.  */\n"                         \
 280 "       { .mmi\n"                                                             \
 281 "         ld8 r3 = [loc2], 8\n"                                               \
 282 "         mov b0 = r0\n"                                                      \
 283 "       }\n"                                                                  \
 284 "       { .mmi\n"                                                             \
 285 "         addl ret0 = @ltoff(@fptr(_dl_fini#)), gp\n"                         \
 286 "         ;;\n"                                                               \
 287 "         mov b6 = r3\n"                                                      \
 288 "       }\n"                                                                  \
 289 "       { .mmi\n"                                                             \
 290 "         ld8 ret0 = [ret0]\n"                                                \
 291 "         ld8 gp = [loc2]\n"                                                  \
 292 "         mov ar.pfs = loc0\n"                                                \
 293 "         ;;\n"                                                               \
 294 "       }\n"                                                                  \
 295 "       { .mfb\n"                                                             \
 296 "         br.sptk.many b6\n"                                                  \
 297 "         ;;\n"                                                               \
 298 "       }\n"                                                                  \
 299 "       .endp _dl_start_user#\n"                                              \
 300 ".previous\n");
 301
 302
 303 #ifndef RTLD_START_SPECIAL_INIT
 304 #define RTLD_START_SPECIAL_INIT /* nothing */
 305 #endif
 306
 307 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or TLS
 308    variable, so undefined references should not be allowed to define the
 309    value.
 310    ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
 311    of the main executable's symbols, as for a COPY reloc, which we don't
 312    use.  */
 313 /* ??? Ignore *MSB for now.  */
 314 #define elf_machine_type_class(type) \
 315   (((type) == R_IA64_IPLTLSB || (type) == R_IA64_DTPMOD64LSB                  \
 316     || (type) == R_IA64_DTPREL64LSB || (type) == R_IA64_TPREL64LSB)           \
 317    * ELF_RTYPE_CLASS_PLT)
 318
 319 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
 320 #define ELF_MACHINE_JMP_SLOT     R_IA64_IPLTLSB
 321
 322 /* According to the IA-64 specific documentation, Rela is always used.  */
 323 #define ELF_MACHINE_NO_REL 1
 324
 325 /* Return the address of the entry point. */
 326 #define ELF_MACHINE_START_ADDRESS(map, start)   \
 327   DL_STATIC_FUNCTION_ADDRESS (map, start)
 328
 329 /* Fixup a PLT entry to bounce directly to the function at VALUE.  */
 330 static inline struct fdesc __attribute__ ((always_inline))
 331 elf_machine_fixup_plt (struct link_map *l, lookup_t t,
 332                        const Elf64_Rela *reloc,
 333                        Elf64_Addr *reloc_addr, struct fdesc value)
 334 {
 335   /* l is the link_map for the caller, t is the link_map for the object
 336    * being called */
 337   /* got has already been relocated in elf_get_dynamic_info() */
 338   reloc_addr[1] = value.gp;
 339   /* we need a "release" here to ensure that the gp is visible before
 340      the code entry point is updated: */
 341   ((volatile Elf64_Addr *) reloc_addr)[0] = value.ip;
 342   return value;
 343 }
 344
 345 /* Return the final value of a plt relocation.  */
 346 static inline struct fdesc
 347 elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
 348                        struct fdesc value)
 349 {
 350   /* No need to handle rel vs rela since IA64 is rela only */
 351   return (struct fdesc) { value.ip + reloc->r_addend, value.gp };
 352 }
 353
 354 #endif /* !dl_machine_h */
 355
 356 #ifdef RESOLVE_MAP
 357
 358 #define R_IA64_TYPE(R)   ((R) & -8)
 359 #define R_IA64_FORMAT(R) ((R) & 7)
 360
 361 #define R_IA64_FORMAT_32MSB     4
 362 #define R_IA64_FORMAT_32LSB     5
 363 #define R_IA64_FORMAT_64MSB     6
 364 #define R_IA64_FORMAT_64LSB     7
 365
 366
 367 /* Perform the relocation specified by RELOC and SYM (which is fully
 368    resolved).  MAP is the object containing the reloc.  */
 369 auto inline void
 370 __attribute ((always_inline))
 371 elf_machine_rela (struct link_map *map,
 372                   const Elf64_Rela *reloc,
 373                   const Elf64_Sym *sym,
 374                   const struct r_found_version *version,
 375                   void *const reloc_addr_arg,
 376                   int skip_ifunc)
 377 {
 378   Elf64_Addr *const reloc_addr = reloc_addr_arg;
 379   const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
 380   Elf64_Addr value;
 381
 382 #if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC && !defined SHARED
 383   /* This is defined in rtld.c, but nowhere in the static libc.a; make the
 384      reference weak so static programs can still link.  This declaration
 385      cannot be done when compiling rtld.c (i.e.  #ifdef RTLD_BOOTSTRAP)
 386      because rtld.c contains the common defn for _dl_rtld_map, which is
 387      incompatible with a weak decl in the same file.  */
 388   weak_extern (_dl_rtld_map);
 389 #endif
 390
 391   /* We cannot use a switch here because we cannot locate the switch
 392      jump table until we've self-relocated.  */
 393
 394 #if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
 395   if (__builtin_expect (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_REL64LSB),
 396                         0))
 397     {
 398       assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
 399       value = *reloc_addr;
 400 # if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
 401       /* Already done in dynamic linker.  */
 402       if (map != &GL(dl_rtld_map))
 403 # endif
 404         value += map->l_addr;
 405     }
 406   else
 407 #endif
 408     if (__builtin_expect (r_type == R_IA64_NONE, 0))
 409       return;
 410   else
 411     {
 412       struct link_map *sym_map;
 413
 414       /* RESOLVE_MAP() will return NULL if it fail to locate the symbol.  */
 415       if ((sym_map = RESOLVE_MAP (&sym, version, r_type)))
 416         {
 417           value = sym_map->l_addr + sym->st_value + reloc->r_addend;
 418
 419           if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DIR64LSB))
 420             ;/* No adjustment.  */
 421           else if (r_type == R_IA64_IPLTLSB)
 422             {
 423               elf_machine_fixup_plt (NULL, NULL, reloc, reloc_addr,
 424                                      DL_FIXUP_MAKE_VALUE (sym_map, value));
 425               return;
 426             }
 427           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_FPTR64LSB))
 428             value = _dl_make_fptr (sym_map, sym, value);
 429           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_PCREL64LSB))
 430             value -= (Elf64_Addr) reloc_addr & -16;
 431           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPMOD64LSB))
 432 #ifdef RTLD_BOOTSTRAP
 433             /* During startup the dynamic linker is always index 1.  */
 434             value = 1;
 435 #else
 436             /* Get the information from the link map returned by the
 437                resolv function.  */
 438             value = sym_map->l_tls_modid;
 439           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPREL64LSB))
 440             value -= sym_map->l_addr;
 441 #endif
 442           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_TPREL64LSB))
 443             {
 444 #ifndef RTLD_BOOTSTRAP
 445               CHECK_STATIC_TLS (map, sym_map);
 446 #endif
 447               value += sym_map->l_tls_offset - sym_map->l_addr;
 448             }
 449           else
 450             _dl_reloc_bad_type (map, r_type, 0);
 451         }
 452       else
 453         value = 0;
 454     }
 455
 456   /* ??? Ignore MSB and Instruction format for now.  */
 457   if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_64LSB)
 458     *reloc_addr = value;
 459   else if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_32LSB)
 460     *(int *) reloc_addr = value;
 461   else if (r_type == R_IA64_IPLTLSB)
 462     {
 463       reloc_addr[0] = 0;
 464       reloc_addr[1] = 0;
 465     }
 466   else
 467     _dl_reloc_bad_type (map, r_type, 0);
 468 }
 469
 470 /* Let do-rel.h know that on IA-64 if l_addr is 0, all RELATIVE relocs
 471    can be skipped.  */
 472 #define ELF_MACHINE_REL_RELATIVE 1
 473
 474 auto inline void
 475 __attribute ((always_inline))
 476 elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
 477                            void *const reloc_addr_arg)
 478 {
 479   Elf64_Addr *const reloc_addr = reloc_addr_arg;
 480   /* ??? Ignore MSB and Instruction format for now.  */
 481   assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
 482
 483   *reloc_addr += l_addr;
 484 }
 485
 486 /* Perform a RELATIVE reloc on the .got entry that transfers to the .plt.  */
 487 auto inline void
 488 __attribute ((always_inline))
 489 elf_machine_lazy_rel (struct link_map *map,
 490                       Elf64_Addr l_addr, const Elf64_Rela *reloc,
 491                       int skip_ifunc)
 492 {
 493   Elf64_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
 494   const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
 495
 496   if (r_type == R_IA64_IPLTLSB)
 497     {
 498       reloc_addr[0] += l_addr;
 499       reloc_addr[1] += l_addr;
 500     }
 501   else if (r_type == R_IA64_NONE)
 502     return;
 503   else
 504     _dl_reloc_bad_type (map, r_type, 1);
 505 }
 506
 507 #endif /* RESOLVE_MAP */