sysdeps/ia64/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  IA-64 version.
   2    Copyright (C) 1995-2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef dl_machine_h
  20 #define dl_machine_h 1
  21
  22 #define ELF_MACHINE_NAME "ia64"
  23
  24 #include <assert.h>
  25 #include <string.h>
  26 #include <link.h>
  27 #include <errno.h>
  28 #include <dl-fptr.h>
  29 #include <tls.h>
  30
  31 /* Translate a processor specific dynamic tag to the index
  32    in l_info array.  */
  33 #define DT_IA_64(x) (DT_IA_64_##x - DT_LOPROC + DT_NUM)
  34
  35 static inline void __attribute__ ((always_inline))
  36 __ia64_init_bootstrap_fdesc_table (struct link_map *map)
  37 {
  38   Elf64_Addr *boot_table;
  39
  40   /* careful: this will be called before got has been relocated... */
  41   asm (";; addl %0 = @gprel (_dl_boot_fptr_table), gp" : "=r"(boot_table));
  42
  43   map->l_mach.fptr_table_len = ELF_MACHINE_BOOT_FPTR_TABLE_LEN;
  44   map->l_mach.fptr_table = boot_table;
  45 }
  46
  47 #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info)             \
  48         __ia64_init_bootstrap_fdesc_table (BOOTSTRAP_MAP);
  49
  50 /* Return nonzero iff ELF header is compatible with the running host.  */
  51 static inline int __attribute__ ((unused))
  52 elf_machine_matches_host (const Elf64_Ehdr *ehdr)
  53 {
  54   return ehdr->e_machine == EM_IA_64;
  55 }
  56
  57
  58 /* Return the link-time address of _DYNAMIC.  */
  59 static inline Elf64_Addr __attribute__ ((unused, const))
  60 elf_machine_dynamic (void)
  61 {
  62   Elf64_Addr *p;
  63
  64   __asm__ (
  65         ".section .sdata\n"
  66         "       .type __dynamic_ltv#, @object\n"
  67         "       .size __dynamic_ltv#, 8\n"
  68         "__dynamic_ltv:\n"
  69         "       data8   @ltv(_DYNAMIC#)\n"
  70         ".previous\n"
  71         "       addl    %0 = @gprel(__dynamic_ltv#), gp ;;"
  72         : "=r" (p));
  73
  74   return *p;
  75 }
  76
  77
  78 /* Return the run-time load address of the shared object.  */
  79 static inline Elf64_Addr __attribute__ ((unused))
  80 elf_machine_load_address (void)
  81 {
  82   Elf64_Addr ip;
  83   int *p;
  84
  85   __asm__ (
  86         "1:     mov %0 = ip\n"
  87         ".section .sdata\n"
  88         "2:     data4   @ltv(1b)\n"
  89         "       .align 8\n"
  90         ".previous\n"
  91         "       addl    %1 = @gprel(2b), gp ;;"
  92         : "=r" (ip), "=r" (p));
  93
  94   return ip - (Elf64_Addr) *p;
  95 }
  96
  97 /* Set up the loaded object described by L so its unrelocated PLT
  98    entries will jump to the on-demand fixup code in dl-runtime.c.  */
  99
 100 static inline int __attribute__ ((unused, always_inline))
 101 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
 102 {
 103   extern void _dl_runtime_resolve (void);
 104   extern void _dl_runtime_profile (void);
 105
 106   if (lazy)
 107     {
 108       register Elf64_Addr gp __asm__ ("gp");
 109       Elf64_Addr *reserve, doit;
 110
 111       /*
 112        * Careful with the typecast here or it will try to add l-l_addr
 113        * pointer elements
 114        */
 115       reserve = ((Elf64_Addr *)
 116                  (l->l_info[DT_IA_64 (PLT_RESERVE)]->d_un.d_ptr + l->l_addr));
 117       /* Identify this shared object.  */
 118       reserve[0] = (Elf64_Addr) l;
 119
 120       /* This function will be called to perform the relocation.  */
 121       if (!profile)
 122         doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_resolve)->ip;
 123       else
 124         {
 125           if (GLRO(dl_profile) != NULL
 126               && _dl_name_match_p (GLRO(dl_profile), l))
 127             {
 128               /* This is the object we are looking for.  Say that we really
 129                  want profiling and the timers are started.  */
 130               GL(dl_profile_map) = l;
 131             }
 132           doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_profile)->ip;
 133         }
 134
 135       reserve[1] = doit;
 136       reserve[2] = gp;
 137     }
 138
 139   return lazy;
 140 }
 141
 142 /* Names of the architecture-specific auditing callback functions.  */
 143 #define ARCH_LA_PLTENTER ia64_gnu_pltenter
 144 #define ARCH_LA_PLTEXIT ia64_gnu_pltexit
 145
 146 /* Undo the adds out0 = 16, sp below to get at the value we want in
 147    __libc_stack_end.  */
 148 #define DL_STACK_END(cookie) \
 149   ((void *) (((long) (cookie)) - 16))
 150
 151 /* Initial entry point code for the dynamic linker.
 152    The C function `_dl_start' is the real entry point;
 153    its return value is the user program's entry point.  */
 154
 155 #define RTLD_START asm (                                                      \
 156 ".text\n"                                                                     \
 157 "       .global _start#\n"                                                    \
 158 "       .proc _start#\n"                                                      \
 159 "_start:\n"                                                                   \
 160 "0:     { .mii\n"                                                             \
 161 "         .prologue\n"                                                        \
 162 "         .save rp, r0\n"                                                     \
 163 "         .body\n"                                                            \
 164 "         .prologue\n"                                                        \
 165 "         .save ar.pfs, r32\n"                                                \
 166 "         alloc loc0 = ar.pfs, 0, 3, 4, 0\n"                                  \
 167 "         .body\n"                                                            \
 168 "         mov r2 = ip\n"                                                      \
 169 "         addl r3 = @gprel(0b), r0\n"                                         \
 170 "         ;;\n"                                                               \
 171 "       }\n"                                                                  \
 172 "       { .mlx\n"                                                             \
 173 "         /* Calculate the GP, and save a copy in loc1.  */\n"                \
 174 "         sub gp = r2, r3\n"                                                  \
 175 "         movl r8 = 0x9804c0270033f\n"                                        \
 176 "         ;;\n"                                                               \
 177 "       }\n"                                                                  \
 178 "       { .mii\n"                                                             \
 179 "         mov ar.fpsr = r8\n"                                                 \
 180 "         sub loc1 = r2, r3\n"                                                \
 181 "         /* _dl_start wants a pointer to the pointer to the arg block and\n" \
 182 "            the arg block starts with an integer, thus the magic 16. */\n"   \
 183 "         adds out0 = 16, sp\n"                                               \
 184 "       }\n"                                                                  \
 185 "       { .bbb\n"                                                             \
 186 "         br.call.sptk.many b0 = _dl_start#\n"                                \
 187 "         ;;\n"                                                               \
 188 "       }\n"                                                                  \
 189 "       .endp _start#\n"                                                      \
 190 "       /* FALLTHRU */\n"                                                     \
 191 "       .global _dl_start_user#\n"                                            \
 192 "       .proc _dl_start_user#\n"                                              \
 193 "_dl_start_user:\n"                                                           \
 194 "        .prologue\n"                                                         \
 195 "        .save rp, r0\n"                                                      \
 196 "         .body\n"                                                            \
 197 "        .prologue\n"                                                         \
 198 "        .save ar.pfs, r32\n"                                                 \
 199 "        .body\n"                                                             \
 200 "       { .mii\n"                                                             \
 201 "         addl r3 = @gprel(_dl_skip_args), gp\n"                              \
 202 "         adds r11 = 24, sp     /* Load the address of argv. */\n"            \
 203 "         /* Save the pointer to the user entry point fptr in loc2.  */\n"    \
 204 "         mov loc2 = ret0\n"                                                  \
 205 "         ;;\n"                                                               \
 206 "       }\n"                                                                  \
 207 "       { .mii\n"                                                             \
 208 "         ld4 r3 = [r3]\n"                                                    \
 209 "         adds r10 = 16, sp     /* Load the address of argc. */\n"            \
 210 "         mov out2 = r11\n"                                                   \
 211 "         ;;\n"                                                               \
 212 "         /* See if we were run as a command with the executable file\n"      \
 213 "            name as an extra leading argument.  If so, adjust the argv\n"    \
 214 "            pointer to skip _dl_skip_args words.\n"                          \
 215 "            Note that _dl_skip_args is an integer, not a long - Jes\n"       \
 216 "\n"                                                                          \
 217 "            The stack pointer has to be 16 byte aligned. We cannot simply\n" \
 218 "            addjust the stack pointer. We have to move the whole argv and\n" \
 219 "            envp and adjust _dl_argv by _dl_skip_args.  H.J.  */\n"          \
 220 "       }\n"                                                                  \
 221 "       { .mib\n"                                                             \
 222 "         ld8 out1 = [r10]      /* is argc actually stored as a long\n"       \
 223 "                                  or as an int? */\n"                        \
 224 "         addl r2 = @ltoff(_dl_argv), gp\n"                                   \
 225 "         ;;\n"                                                               \
 226 "       }\n"                                                                  \
 227 "       { .mmi\n"                                                             \
 228 "         ld8 r2 = [r2]         /* Get the address of _dl_argv. */\n"         \
 229 "         sub out1 = out1, r3   /* Get the new argc. */\n"                    \
 230 "         shladd r3 = r3, 3, r0\n"                                            \
 231 "         ;;\n"                                                               \
 232 "       }\n"                                                                  \
 233 "       {\n"                                                                  \
 234 "         .mib\n"                                                             \
 235 "         ld8 r17 = [r2]        /* Get _dl_argv. */\n"                        \
 236 "         add r15 = r11, r3     /* The address of the argv we move */\n"      \
 237 "         ;;\n"                                                               \
 238 "       }\n"                                                                  \
 239 "       /* ??? Could probably merge these two loops into 3 bundles.\n"        \
 240 "          using predication to control which set of copies we're on.  */\n"  \
 241 "1:     /* Copy argv. */\n"                                                   \
 242 "       { .mfi\n"                                                             \
 243 "         ld8 r16 = [r15], 8    /* Load the value in the old argv. */\n"      \
 244 "         ;;\n"                                                               \
 245 "       }\n"                                                                  \
 246 "       { .mib\n"                                                             \
 247 "         st8 [r11] = r16, 8    /* Store it in the new argv. */\n"            \
 248 "         cmp.ne p6, p7 = 0, r16\n"                                           \
 249 "(p6)     br.cond.dptk.few 1b\n"                                              \
 250 "         ;;\n"                                                               \
 251 "       }\n"                                                                  \
 252 "       { .mmi\n"                                                             \
 253 "         mov out3 = r11\n"                                                   \
 254 "         sub r17 = r17, r3     /* Substract _dl_skip_args. */\n"             \
 255 "         addl out0 = @gprel(_rtld_local), gp\n"                              \
 256 "       }\n"                                                                  \
 257 "1:     /* Copy env. */\n"                                                    \
 258 "       { .mfi\n"                                                             \
 259 "         ld8 r16 = [r15], 8    /* Load the value in the old env. */\n"       \
 260 "         ;;\n"                                                               \
 261 "       }\n"                                                                  \
 262 "       { .mib\n"                                                             \
 263 "         st8 [r11] = r16, 8    /* Store it in the new env. */\n"             \
 264 "         cmp.ne p6, p7 = 0, r16\n"                                           \
 265 "(p6)     br.cond.dptk.few 1b\n"                                              \
 266 "         ;;\n"                                                               \
 267 "       }\n"                                                                  \
 268 "       { .mmb\n"                                                             \
 269 "         st8 [r10] = out1              /* Record the new argc. */\n"         \
 270 "         ld8 out0 = [out0]             /* get the linkmap */\n"              \
 271 "       }\n"                                                                  \
 272 "       { .mmb\n"                                                             \
 273 "         st8 [r2] = r17                /* Load the new _dl_argv. */\n"       \
 274 "         br.call.sptk.many b0 = _dl_init#\n"                                 \
 275 "         ;;\n"                                                               \
 276 "       }\n"                                                                  \
 277 "       /* Pass our finalizer function to the user,\n"                        \
 278 "          and jump to the user's entry point.  */\n"                         \
 279 "       { .mmi\n"                                                             \
 280 "         ld8 r3 = [loc2], 8\n"                                               \
 281 "         mov b0 = r0\n"                                                      \
 282 "       }\n"                                                                  \
 283 "       { .mmi\n"                                                             \
 284 "         addl ret0 = @ltoff(@fptr(_dl_fini#)), gp\n"                         \
 285 "         ;;\n"                                                               \
 286 "         mov b6 = r3\n"                                                      \
 287 "       }\n"                                                                  \
 288 "       { .mmi\n"                                                             \
 289 "         ld8 ret0 = [ret0]\n"                                                \
 290 "         ld8 gp = [loc2]\n"                                                  \
 291 "         mov ar.pfs = loc0\n"                                                \
 292 "         ;;\n"                                                               \
 293 "       }\n"                                                                  \
 294 "       { .mfb\n"                                                             \
 295 "         br.sptk.many b6\n"                                                  \
 296 "         ;;\n"                                                               \
 297 "       }\n"                                                                  \
 298 "       .endp _dl_start_user#\n"                                              \
 299 ".previous\n");
 300
 301
 302 #ifndef RTLD_START_SPECIAL_INIT
 303 #define RTLD_START_SPECIAL_INIT /* nothing */
 304 #endif
 305
 306 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or TLS
 307    variable, so undefined references should not be allowed to define the
 308    value.
 309    ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
 310    of the main executable's symbols, as for a COPY reloc, which we don't
 311    use.  */
 312 /* ??? Ignore *MSB for now.  */
 313 #define elf_machine_type_class(type) \
 314   (((type) == R_IA64_IPLTLSB || (type) == R_IA64_DTPMOD64LSB                  \
 315     || (type) == R_IA64_DTPREL64LSB || (type) == R_IA64_TPREL64LSB)           \
 316    * ELF_RTYPE_CLASS_PLT)
 317
 318 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
 319 #define ELF_MACHINE_JMP_SLOT     R_IA64_IPLTLSB
 320
 321 /* According to the IA-64 specific documentation, Rela is always used.  */
 322 #define ELF_MACHINE_NO_REL 1
 323 #define ELF_MACHINE_NO_RELA 0
 324
 325 /* Return the address of the entry point. */
 326 #define ELF_MACHINE_START_ADDRESS(map, start)                   \
 327 ({                                                              \
 328         ElfW(Addr) addr;                                        \
 329         DL_DT_FUNCTION_ADDRESS(map, start, static, addr)        \
 330         addr;                                                   \
 331 })
 332
 333 /* Fixup a PLT entry to bounce directly to the function at VALUE.  */
 334 static inline struct fdesc __attribute__ ((always_inline))
 335 elf_machine_fixup_plt (struct link_map *l, lookup_t t,
 336                        const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
 337                        const Elf64_Rela *reloc,
 338                        Elf64_Addr *reloc_addr, struct fdesc value)
 339 {
 340   /* l is the link_map for the caller, t is the link_map for the object
 341    * being called */
 342   /* got has already been relocated in elf_get_dynamic_info() */
 343   reloc_addr[1] = value.gp;
 344   /* we need a "release" here to ensure that the gp is visible before
 345      the code entry point is updated: */
 346   ((volatile Elf64_Addr *) reloc_addr)[0] = value.ip;
 347   return value;
 348 }
 349
 350 /* Return the final value of a plt relocation.  */
 351 static inline struct fdesc
 352 elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
 353                        struct fdesc value)
 354 {
 355   /* No need to handle rel vs rela since IA64 is rela only */
 356   return (struct fdesc) { value.ip + reloc->r_addend, value.gp };
 357 }
 358
 359 #endif /* !dl_machine_h */
 360
 361 #ifdef RESOLVE_MAP
 362
 363 #define R_IA64_TYPE(R)   ((R) & -8)
 364 #define R_IA64_FORMAT(R) ((R) & 7)
 365
 366 #define R_IA64_FORMAT_32MSB     4
 367 #define R_IA64_FORMAT_32LSB     5
 368 #define R_IA64_FORMAT_64MSB     6
 369 #define R_IA64_FORMAT_64LSB     7
 370
 371
 372 /* Perform the relocation specified by RELOC and SYM (which is fully
 373    resolved).  MAP is the object containing the reloc.  */
 374 auto inline void
 375 __attribute ((always_inline))
 376 elf_machine_rela (struct link_map *map,
 377                   const Elf64_Rela *reloc,
 378                   const Elf64_Sym *sym,
 379                   const struct r_found_version *version,
 380                   void *const reloc_addr_arg,
 381                   int skip_ifunc)
 382 {
 383   Elf64_Addr *const reloc_addr = reloc_addr_arg;
 384   const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
 385   Elf64_Addr value;
 386
 387 #if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC && !defined SHARED
 388   /* This is defined in rtld.c, but nowhere in the static libc.a; make the
 389      reference weak so static programs can still link.  This declaration
 390      cannot be done when compiling rtld.c (i.e.  #ifdef RTLD_BOOTSTRAP)
 391      because rtld.c contains the common defn for _dl_rtld_map, which is
 392      incompatible with a weak decl in the same file.  */
 393   weak_extern (_dl_rtld_map);
 394 #endif
 395
 396   /* We cannot use a switch here because we cannot locate the switch
 397      jump table until we've self-relocated.  */
 398
 399 #if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
 400   if (__builtin_expect (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_REL64LSB),
 401                         0))
 402     {
 403       assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
 404       value = *reloc_addr;
 405 # if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
 406       /* Already done in dynamic linker.  */
 407       if (map != &GL(dl_rtld_map))
 408 # endif
 409         value += map->l_addr;
 410     }
 411   else
 412 #endif
 413     if (__builtin_expect (r_type == R_IA64_NONE, 0))
 414       return;
 415   else
 416     {
 417       struct link_map *sym_map;
 418
 419       /* RESOLVE_MAP() will return NULL if it fail to locate the symbol.  */
 420       if ((sym_map = RESOLVE_MAP (&sym, version, r_type)))
 421         {
 422           value = SYMBOL_ADDRESS (sym_map, sym, true) + reloc->r_addend;
 423
 424           if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DIR64LSB))
 425             ;/* No adjustment.  */
 426           else if (r_type == R_IA64_IPLTLSB)
 427             {
 428               elf_machine_fixup_plt (NULL, NULL, NULL, NULL, reloc, reloc_addr,
 429                                      DL_FIXUP_MAKE_VALUE (sym_map, value));
 430               return;
 431             }
 432           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_FPTR64LSB))
 433             value = _dl_make_fptr (sym_map, sym, value);
 434           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_PCREL64LSB))
 435             value -= (Elf64_Addr) reloc_addr & -16;
 436           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPMOD64LSB))
 437 #ifdef RTLD_BOOTSTRAP
 438             /* During startup the dynamic linker is always index 1.  */
 439             value = 1;
 440 #else
 441             /* Get the information from the link map returned by the
 442                resolv function.  */
 443             value = sym_map->l_tls_modid;
 444           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPREL64LSB))
 445             value -= sym_map->l_addr;
 446 #endif
 447           else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_TPREL64LSB))
 448             {
 449 #ifndef RTLD_BOOTSTRAP
 450               CHECK_STATIC_TLS (map, sym_map);
 451 #endif
 452               value += sym_map->l_tls_offset - sym_map->l_addr;
 453             }
 454           else
 455             _dl_reloc_bad_type (map, r_type, 0);
 456         }
 457       else
 458         value = 0;
 459     }
 460
 461   /* ??? Ignore MSB and Instruction format for now.  */
 462   if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_64LSB)
 463     *reloc_addr = value;
 464   else if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_32LSB)
 465     *(int *) reloc_addr = value;
 466   else if (r_type == R_IA64_IPLTLSB)
 467     {
 468       reloc_addr[0] = 0;
 469       reloc_addr[1] = 0;
 470     }
 471   else
 472     _dl_reloc_bad_type (map, r_type, 0);
 473 }
 474
 475 /* Let do-rel.h know that on IA-64 if l_addr is 0, all RELATIVE relocs
 476    can be skipped.  */
 477 #define ELF_MACHINE_REL_RELATIVE 1
 478
 479 auto inline void
 480 __attribute ((always_inline))
 481 elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
 482                            void *const reloc_addr_arg)
 483 {
 484   Elf64_Addr *const reloc_addr = reloc_addr_arg;
 485   /* ??? Ignore MSB and Instruction format for now.  */
 486   assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
 487
 488   *reloc_addr += l_addr;
 489 }
 490
 491 /* Perform a RELATIVE reloc on the .got entry that transfers to the .plt.  */
 492 auto inline void
 493 __attribute ((always_inline))
 494 elf_machine_lazy_rel (struct link_map *map,
 495                       Elf64_Addr l_addr, const Elf64_Rela *reloc,
 496                       int skip_ifunc)
 497 {
 498   Elf64_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
 499   const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
 500
 501   if (r_type == R_IA64_IPLTLSB)
 502     {
 503       reloc_addr[0] += l_addr;
 504       reloc_addr[1] += l_addr;
 505     }
 506   else if (r_type == R_IA64_NONE)
 507     return;
 508   else
 509     _dl_reloc_bad_type (map, r_type, 1);
 510 }
 511
 512 #endif /* RESOLVE_MAP */