sysdeps/sh/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  SH version.
   2    Copyright (C) 1999-2014 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef dl_machine_h
  20 #define dl_machine_h
  21
  22 #define ELF_MACHINE_NAME "SH"
  23
  24 #include <sys/param.h>
  25 #include <sysdep.h>
  26 #include <assert.h>
  27
  28 /* Return nonzero iff ELF header is compatible with the running host.  */
  29 static inline int __attribute__ ((unused))
  30 elf_machine_matches_host (const Elf32_Ehdr *ehdr)
  31 {
  32   return ehdr->e_machine == EM_SH;
  33 }
  34
  35
  36 /* Return the link-time address of _DYNAMIC.  Conveniently, this is the
  37    first element of the GOT.  This must be inlined in a function which
  38    uses global data.  */
  39 static inline Elf32_Addr __attribute__ ((unused))
  40 elf_machine_dynamic (void)
  41 {
  42   register Elf32_Addr *got;
  43   asm ("mov r12,%0" :"=r" (got));
  44   return *got;
  45 }
  46
  47
  48 /* Return the run-time load address of the shared object.  */
  49 static inline Elf32_Addr __attribute__ ((unused))
  50 elf_machine_load_address (void)
  51 {
  52   Elf32_Addr addr;
  53   asm ("mov.l 1f,r0\n\
  54         mov.l 3f,r2\n\
  55         add r12,r2\n\
  56         mov.l @(r0,r12),r0\n\
  57         bra 2f\n\
  58          sub r0,r2\n\
  59         .align 2\n\
  60         1: .long _dl_start@GOT\n\
  61         3: .long _dl_start@GOTOFF\n\
  62         2: mov r2,%0"
  63        : "=r" (addr) : : "r0", "r1", "r2");
  64   return addr;
  65 }
  66
  67
  68 /* Set up the loaded object described by L so its unrelocated PLT
  69    entries will jump to the on-demand fixup code in dl-runtime.c.  */
  70
  71 static inline int __attribute__ ((unused, always_inline))
  72 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
  73 {
  74   Elf32_Addr *got;
  75   extern void _dl_runtime_resolve (Elf32_Word);
  76   extern void _dl_runtime_profile (Elf32_Word);
  77
  78   if (l->l_info[DT_JMPREL] && lazy)
  79     {
  80       /* The GOT entries for functions in the PLT have not yet been filled
  81          in.  Their initial contents will arrange when called to load an
  82          offset into the .rela.plt section and _GLOBAL_OFFSET_TABLE_[1],
  83          and then jump to _GLOBAL_OFFSET_TABLE[2].  */
  84       got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
  85       /* If a library is prelinked but we have to relocate anyway,
  86          we have to be able to undo the prelinking of .got.plt.
  87          The prelinker saved us here address of .plt + 36.  */
  88       if (got[1])
  89         {
  90           l->l_mach.plt = got[1] + l->l_addr;
  91           l->l_mach.gotplt = (Elf32_Addr) &got[3];
  92         }
  93       got[1] = (Elf32_Addr) l;  /* Identify this shared object.  */
  94
  95       /* The got[2] entry contains the address of a function which gets
  96          called to get the address of a so far unresolved function and
  97          jump to it.  The profiling extension of the dynamic linker allows
  98          to intercept the calls to collect information.  In this case we
  99          don't store the address in the GOT so that all future calls also
 100          end in this function.  */
 101       if (profile)
 102         {
 103           got[2] = (Elf32_Addr) &_dl_runtime_profile;
 104           /* Say that we really want profiling and the timers are started.  */
 105           if (GLRO(dl_profile) != NULL
 106               && _dl_name_match_p (GLRO(dl_profile), l))
 107             GL(dl_profile_map) = l;
 108         }
 109       else
 110         /* This function will get called to fix up the GOT entry indicated by
 111            the offset on the stack, and then jump to the resolved address.  */
 112         got[2] = (Elf32_Addr) &_dl_runtime_resolve;
 113     }
 114   return lazy;
 115 }
 116
 117 #define ELF_MACHINE_RUNTIME_FIXUP_ARGS int plt_type
 118 #define ELF_MACHINE_RUNTIME_FIXUP_PARAMS plt_type
 119
 120 /* Mask identifying addresses reserved for the user program,
 121    where the dynamic linker should not map anything.  */
 122 #define ELF_MACHINE_USER_ADDRESS_MASK   0x80000000UL
 123
 124 /* Initial entry point code for the dynamic linker.
 125    The C function `_dl_start' is the real entry point;
 126    its return value is the user program's entry point.  */
 127
 128 #define RTLD_START asm ("\
 129 .text\n\
 130 .globl _start\n\
 131 .globl _dl_start_user\n\
 132 _start:\n\
 133         mov r15,r4\n\
 134         mov.l .L_dl_start,r1\n\
 135         mova .L_dl_start,r0\n\
 136         add r1,r0\n\
 137         jsr @r0\n\
 138          nop\n\
 139 _dl_start_user:\n\
 140         ! Save the user entry point address in r8.\n\
 141         mov r0,r8\n\
 142         ! Point r12 at the GOT.\n\
 143         mov.l 1f,r12\n\
 144         mova 1f,r0\n\
 145         bra 2f\n\
 146          add r0,r12\n\
 147         .align 2\n\
 148 1:      .long _GLOBAL_OFFSET_TABLE_\n\
 149 2:      ! See if we were run as a command with the executable file\n\
 150         ! name as an extra leading argument.\n\
 151         mov.l .L_dl_skip_args,r0\n\
 152         mov.l @(r0,r12),r0\n\
 153         mov.l @r0,r0\n\
 154         ! Get the original argument count.\n\
 155         mov.l @r15,r5\n\
 156         ! Subtract _dl_skip_args from it.\n\
 157         sub r0,r5\n\
 158         ! Adjust the stack pointer to skip _dl_skip_args words.\n\
 159         shll2 r0\n\
 160         add r0,r15\n\
 161         ! Store back the modified argument count.\n\
 162         mov.l r5,@r15\n\
 163         ! Compute argv address and envp.\n\
 164         mov r15,r6\n\
 165         add #4,r6\n\
 166         mov r5,r7\n\
 167         shll2 r7\n\
 168         add r15,r7\n\
 169         add #8,r7\n\
 170         mov.l .L_dl_loaded,r0\n\
 171         mov.l @(r0,r12),r0\n\
 172         mov.l @r0,r4\n\
 173         ! Call _dl_init.\n\
 174         mov.l .L_dl_init,r1\n\
 175         mova .L_dl_init,r0\n\
 176         add r1,r0\n\
 177         jsr @r0\n\
 178          nop\n\
 179 1:      ! Pass our finalizer function to the user in r4, as per ELF ABI.\n\
 180         mov.l .L_dl_fini,r0\n\
 181         mov.l @(r0,r12),r4\n\
 182         ! Jump to the user's entry point.\n\
 183         jmp @r8\n\
 184          nop\n\
 185         .align 2\n\
 186 .L_dl_start:\n\
 187         .long _dl_start@PLT\n\
 188 .L_dl_skip_args:\n\
 189         .long _dl_skip_args@GOT\n\
 190 .L_dl_init:\n\
 191         .long _dl_init_internal@PLT\n\
 192 .L_dl_loaded:\n\
 193         .long _rtld_local@GOT\n\
 194 .L_dl_fini:\n\
 195         .long _dl_fini@GOT\n\
 196         .type __fpscr_values,@object\n\
 197         .global __fpscr_values\n\
 198 __fpscr_values:\n\
 199         .long   0\n\
 200         .long   0x80000\n\
 201         .weak __fpscr_values\n\
 202 .previous\n\
 203 ");
 204
 205 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
 206    TLS variable, so undefined references should not be allowed to
 207    define the value.
 208    ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
 209    of the main executable's symbols, as for a COPY reloc.  */
 210 #define elf_machine_type_class(type) \
 211   ((((type) == R_SH_JMP_SLOT || (type) == R_SH_TLS_DTPMOD32                   \
 212      || (type) == R_SH_TLS_DTPOFF32 || (type) == R_SH_TLS_TPOFF32)            \
 213     * ELF_RTYPE_CLASS_PLT)                                                    \
 214    | (((type) == R_SH_COPY) * ELF_RTYPE_CLASS_COPY))
 215
 216 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
 217 #define ELF_MACHINE_JMP_SLOT    R_SH_JMP_SLOT
 218
 219 /* We define an initialization functions.  This is called very early in
 220    _dl_sysdep_start.  */
 221 #define DL_PLATFORM_INIT dl_platform_init ()
 222
 223 static inline void __attribute__ ((unused))
 224 dl_platform_init (void)
 225 {
 226   if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
 227     /* Avoid an empty string which would disturb us.  */
 228     GLRO(dl_platform) = NULL;
 229 }
 230
 231 static inline Elf32_Addr
 232 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
 233                        const Elf32_Rela *reloc,
 234                        Elf32_Addr *reloc_addr, Elf32_Addr value)
 235 {
 236   return *reloc_addr = value;
 237 }
 238
 239 /* Return the final value of a plt relocation.  */
 240 static inline Elf32_Addr
 241 elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
 242                        Elf32_Addr value)
 243 {
 244   return value + reloc->r_addend;
 245 }
 246
 247 #define ARCH_LA_PLTENTER sh_gnu_pltenter
 248 #define ARCH_LA_PLTEXIT sh_gnu_pltexit
 249
 250 #endif /* !dl_machine_h */
 251
 252 /* SH never uses Elf32_Rel relocations.  */
 253 #define ELF_MACHINE_NO_REL 1
 254
 255 #ifdef RESOLVE_MAP
 256
 257 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
 258    MAP is the object containing the reloc.  */
 259
 260 auto inline void
 261 __attribute ((always_inline))
 262 elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 263                   const Elf32_Sym *sym, const struct r_found_version *version,
 264                   void *const reloc_addr_arg, int skip_ifunc)
 265 {
 266   Elf32_Addr *const reloc_addr = reloc_addr_arg;
 267   const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
 268   Elf32_Addr value;
 269
 270 #define COPY_UNALIGNED_WORD(swp, twp, align) \
 271   { \
 272     void *__s = (swp), *__t = (twp); \
 273     unsigned char *__s1 = __s, *__t1 = __t; \
 274     unsigned short *__s2 = __s, *__t2 = __t; \
 275     unsigned long *__s4 = __s, *__t4 = __t; \
 276     switch ((align)) \
 277     { \
 278     case 0: \
 279       *__t4 = *__s4; \
 280       break; \
 281     case 2: \
 282       *__t2++ = *__s2++; \
 283       *__t2 = *__s2; \
 284       break; \
 285     default: \
 286       *__t1++ = *__s1++; \
 287       *__t1++ = *__s1++; \
 288       *__t1++ = *__s1++; \
 289       *__t1 = *__s1; \
 290       break; \
 291     } \
 292   }
 293
 294   if (__builtin_expect (r_type == R_SH_RELATIVE, 0))
 295     {
 296 #ifndef RTLD_BOOTSTRAP
 297       if (map != &GL(dl_rtld_map)) /* Already done in rtld itself.       */
 298 #endif
 299         {
 300           if (reloc->r_addend)
 301             value = map->l_addr + reloc->r_addend;
 302           else
 303             {
 304               COPY_UNALIGNED_WORD (reloc_addr_arg, &value,
 305                                    (int) reloc_addr_arg & 3);
 306               value += map->l_addr;
 307             }
 308           COPY_UNALIGNED_WORD (&value, reloc_addr_arg,
 309                                (int) reloc_addr_arg & 3);
 310         }
 311     }
 312 #ifndef RTLD_BOOTSTRAP
 313   else if (__builtin_expect (r_type == R_SH_NONE, 0))
 314     return;
 315 #endif
 316   else
 317     {
 318       const Elf32_Sym *const refsym = sym;
 319       struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
 320
 321       value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value;
 322       value += reloc->r_addend;
 323
 324       switch (r_type)
 325         {
 326         case R_SH_COPY:
 327           if (sym == NULL)
 328             /* This can happen in trace mode if an object could not be
 329                found.  */
 330             break;
 331           if (sym->st_size > refsym->st_size
 332               || (sym->st_size < refsym->st_size && GLRO(dl_verbose)))
 333             {
 334               const char *strtab;
 335
 336               strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
 337               _dl_error_printf ("\
 338 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
 339                                 RTLD_PROGNAME, strtab + refsym->st_name);
 340             }
 341           memcpy (reloc_addr_arg, (void *) value,
 342                   MIN (sym->st_size, refsym->st_size));
 343           break;
 344         case R_SH_GLOB_DAT:
 345         case R_SH_JMP_SLOT:
 346           /* These addresses are always aligned.  */
 347           *reloc_addr = value;
 348           break;
 349           /* XXX Remove TLS relocations which are not needed.  */
 350         case R_SH_TLS_DTPMOD32:
 351 #ifdef RTLD_BOOTSTRAP
 352           /* During startup the dynamic linker is always the module
 353              with index 1.
 354              XXX If this relocation is necessary move before RESOLVE
 355              call.  */
 356           *reloc_addr = 1;
 357 #else
 358           /* Get the information from the link map returned by the
 359              resolv function.  */
 360           if (sym_map != NULL)
 361             *reloc_addr = sym_map->l_tls_modid;
 362 #endif
 363           break;
 364         case R_SH_TLS_DTPOFF32:
 365 #ifndef RTLD_BOOTSTRAP
 366           /* During relocation all TLS symbols are defined and used.
 367              Therefore the offset is already correct.  */
 368           if (sym != NULL)
 369             *reloc_addr = sym->st_value;
 370 #endif
 371           break;
 372         case R_SH_TLS_TPOFF32:
 373           /* The offset is positive, afterward from the thread pointer.  */
 374 #ifdef RTLD_BOOTSTRAP
 375           *reloc_addr = map->l_tls_offset + sym->st_value + reloc->r_addend;
 376 #else
 377           /* We know the offset of object the symbol is contained in.
 378              It is a positive value which will be added to the thread
 379              pointer.  To get the variable position in the TLS block
 380              we add the offset from that of the TLS block.  */
 381           if (sym != NULL)
 382             {
 383               CHECK_STATIC_TLS (map, sym_map);
 384               *reloc_addr = sym_map->l_tls_offset + sym->st_value
 385                             + reloc->r_addend;
 386             }
 387 #endif
 388           break;
 389         case R_SH_DIR32:
 390           {
 391 #ifndef RTLD_BOOTSTRAP
 392            /* This is defined in rtld.c, but nowhere in the static
 393               libc.a; make the reference weak so static programs can
 394               still link.  This declaration cannot be done when
 395               compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because
 396               rtld.c contains the common defn for _dl_rtld_map, which
 397               is incompatible with a weak decl in the same file.  */
 398 # ifndef SHARED
 399             weak_extern (_dl_rtld_map);
 400 # endif
 401             if (map == &GL(dl_rtld_map))
 402               /* Undo the relocation done here during bootstrapping.
 403                  Now we will relocate it anew, possibly using a
 404                  binding found in the user program or a loaded library
 405                  rather than the dynamic linker's built-in definitions
 406                  used while loading those libraries.  */
 407               value -= map->l_addr + refsym->st_value + reloc->r_addend;
 408 #endif
 409             COPY_UNALIGNED_WORD (&value, reloc_addr_arg,
 410                                  (int) reloc_addr_arg & 3);
 411             break;
 412           }
 413         case R_SH_REL32:
 414           value = (value - (Elf32_Addr) reloc_addr);
 415           COPY_UNALIGNED_WORD (&value, reloc_addr_arg,
 416                                (int) reloc_addr_arg & 3);
 417           break;
 418         default:
 419           _dl_reloc_bad_type (map, r_type, 0);
 420           break;
 421         }
 422     }
 423 }
 424
 425 auto inline void
 426 __attribute__ ((always_inline))
 427 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
 428                            void *const reloc_addr_arg)
 429 {
 430   Elf32_Addr value;
 431
 432   if (reloc->r_addend)
 433     value = l_addr + reloc->r_addend;
 434   else
 435     {
 436       COPY_UNALIGNED_WORD (reloc_addr_arg, &value, (int) reloc_addr_arg & 3);
 437       value += l_addr;
 438     }
 439   COPY_UNALIGNED_WORD (&value, reloc_addr_arg, (int) reloc_addr_arg & 3);
 440
 441 #undef COPY_UNALIGNED_WORD
 442 }
 443
 444 auto inline void
 445 __attribute__ ((always_inline))
 446 elf_machine_lazy_rel (struct link_map *map,
 447                       Elf32_Addr l_addr, const Elf32_Rela *reloc,
 448                       int skip_ifunc)
 449 {
 450   Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
 451   /* Check for unexpected PLT reloc type.  */
 452   if (ELF32_R_TYPE (reloc->r_info) == R_SH_JMP_SLOT)
 453     {
 454       if (__builtin_expect (map->l_mach.plt, 0) == 0)
 455         *reloc_addr += l_addr;
 456       else
 457         *reloc_addr =
 458           map->l_mach.plt
 459           + (((Elf32_Addr) reloc_addr) - map->l_mach.gotplt) * 7;
 460     }
 461   else
 462     _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
 463 }
 464
 465 #endif /* RESOLVE_MAP */