sysdeps/microblaze/dl-machine.h

   1 /* Copyright (C) 1995-2024 Free Software Foundation, Inc.
   2
   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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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
  21
  22 #define ELF_MACHINE_NAME "microblaze"
  23
  24 #include <sys/param.h>
  25 #include <tls.h>
  26 #include <dl-static-tls.h>
  27 #include <dl-machine-rel.h>
  28
  29 /* Return nonzero iff ELF header is compatible with the running host.  */
  30 static inline int
  31 elf_machine_matches_host (const Elf32_Ehdr *ehdr)
  32 {
  33   return (ehdr->e_machine == EM_MICROBLAZE);
  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
  40 elf_machine_dynamic (void)
  41 {
  42   /* This produces a GOTOFF reloc that resolves to zero at link time, so in
  43      fact just loads from the GOT register directly.  By doing it without
  44      an asm we can let the compiler choose any register.  */
  45
  46   Elf32_Addr got_entry_0;
  47   __asm__ __volatile__(
  48     "lwi %0,r20,0"
  49     :"=r"(got_entry_0)
  50     );
  51   return got_entry_0;
  52 }
  53
  54 /* Return the run-time load address of the shared object.  */
  55 static inline Elf32_Addr
  56 elf_machine_load_address (void)
  57 {
  58   /* Compute the difference between the runtime address of _DYNAMIC as seen
  59      by a GOTOFF reference, and the link-time address found in the special
  60      unrelocated first GOT entry.  */
  61
  62   Elf32_Addr dyn;
  63   __asm__ __volatile__ (
  64     "addik %0,r20,_DYNAMIC@GOTOFF"
  65     : "=r"(dyn)
  66     );
  67   return dyn - elf_machine_dynamic ();
  68 }
  69
  70 /* Set up the loaded object described by L so its unrelocated PLT
  71    entries will jump to the on-demand fixup code in dl-runtime.c.  */
  72
  73 static inline int __attribute__ ((always_inline))
  74 elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
  75                            int lazy, int profile)
  76 {
  77   extern void _dl_runtime_resolve (Elf32_Word);
  78   extern void _dl_runtime_profile (Elf32_Word);
  79
  80   return lazy;
  81 }
  82
  83 /* The PLT uses Elf32_Rela relocs.  */
  84 #define elf_machine_relplt elf_machine_rela
  85
  86 /* Mask identifying addresses reserved for the user program,
  87    where the dynamic linker should not map anything.  */
  88 #define ELF_MACHINE_USER_ADDRESS_MASK   0x80000000UL
  89
  90 /* Initial entry point code for the dynamic linker.
  91    The C function `_dl_start' is the real entry point;
  92    its return value is the user program's entry point.  */
  93
  94 #define RTLD_START asm ("\
  95         .text\n\
  96         .globl _start\n\
  97         .type _start,@function\n\
  98 _start:\n\
  99         addk  r5,r0,r1\n\
 100         addk  r3,r0,r0\n\
 101 1:\n\
 102         addik r5,r5,4\n\
 103         lw    r4,r5,r0\n\
 104         bneid r4,1b\n\
 105         addik r3,r3,1\n\
 106         addik r3,r3,-1\n\
 107         addk  r5,r0,r1\n\
 108         sw    r3,r5,r0\n\
 109         addik r1,r1,-24\n\
 110         sw    r15,r1,r0\n\
 111         brlid r15,_dl_start\n\
 112         nop\n\
 113         /* FALLTHRU.  */\n\
 114 \n\
 115         .globl _dl_start_user\n\
 116         .type _dl_start_user,@function\n\
 117 _dl_start_user:\n\
 118         mfs   r20,rpc\n\
 119         addik r20,r20,_GLOBAL_OFFSET_TABLE_+8\n\
 120         lwi   r5,r1,24\n\
 121         swi   r5,r1,24\n\
 122         swi   r3,r1,20\n\
 123         addk  r6,r5,r0\n\
 124         addk  r5,r5,r5\n\
 125         addk  r5,r5,r5\n\
 126         addik r7,r1,28\n\
 127         addk  r8,r7,r5\n\
 128         addik r8,r8,4\n\
 129         lwi   r5,r20,_rtld_local@GOTOFF\n\
 130         brlid r15,_dl_init\n\
 131         nop\n\
 132         lwi   r5,r1,24\n\
 133         lwi   r3,r1,20\n\
 134         addk  r4,r5,r5\n\
 135         addk  r4,r4,r4\n\
 136         addik r6,r1,28\n\
 137         addk  r7,r6,r4\n\
 138         addik r7,r7,4\n\
 139         addik r15,r20,_dl_fini@GOTOFF\n\
 140         addik r15,r15,-8\n\
 141         brad  r3\n\
 142         addik r1,r1,24\n\
 143         nop\n\
 144         .size _dl_start_user, . - _dl_start_user\n\
 145         .previous");
 146
 147 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
 148    TLS variable, so undefined references should not be allowed to
 149    define the value.
 150    ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
 151    of the main executable's symbols, as for a COPY reloc.  */
 152 #ifndef RTLD_BOOTSTRAP
 153 # define elf_machine_type_class(type) \
 154   (((type) == R_MICROBLAZE_JUMP_SLOT \
 155     || (type) == R_MICROBLAZE_TLSDTPREL32 \
 156     || (type) == R_MICROBLAZE_TLSDTPMOD32 \
 157     || (type) == R_MICROBLAZE_TLSTPREL32) \
 158     * ELF_RTYPE_CLASS_PLT \
 159    | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
 160 #else
 161 # define elf_machine_type_class(type) \
 162   (((type) == R_MICROBLAZE_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT \
 163    | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
 164 #endif
 165
 166 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
 167 #define ELF_MACHINE_JMP_SLOT    R_MICROBLAZE_JUMP_SLOT
 168
 169 static inline Elf32_Addr
 170 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
 171                        const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
 172                        const Elf32_Rela *reloc,
 173                        Elf32_Addr *reloc_addr, Elf32_Addr value)
 174 {
 175   return *reloc_addr = value;
 176 }
 177
 178 /* Return the final value of a plt relocation. Ignore the addend.  */
 179 static inline Elf32_Addr
 180 elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
 181                        Elf32_Addr value)
 182 {
 183   return value;
 184 }
 185
 186 #endif /* !dl_machine_h.  */
 187
 188 /* Names of the architecture-specific auditing callback functions.  */
 189 #define ARCH_LA_PLTENTER microblaze_gnu_pltenter
 190 #define ARCH_LA_PLTEXIT microblaze_gnu_pltexit
 191
 192 #ifdef RESOLVE_MAP
 193
 194 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
 195    MAP is the object containing the reloc.  */
 196
 197 /* Macro to put 32-bit relocation value into 2 words.  */
 198 #define PUT_REL_64(rel_addr,val) \
 199   do { \
 200     ((unsigned short *)(rel_addr))[1] = (val) >> 16; \
 201     ((unsigned short *)(rel_addr))[3] = (val) & 0xffff; \
 202   } while (0)
 203
 204 static inline void __attribute__ ((always_inline))
 205 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
 206                   const Elf32_Rela *reloc, const Elf32_Sym *sym,
 207                   const struct r_found_version *version,
 208                   void *const reloc_addr_arg, int skip_ifunc)
 209 {
 210   Elf32_Addr *const reloc_addr = reloc_addr_arg;
 211   const int r_type = ELF32_R_TYPE (reloc->r_info);
 212
 213   if (__builtin_expect (r_type == R_MICROBLAZE_64_PCREL, 0))
 214     PUT_REL_64 (reloc_addr, map->l_addr + reloc->r_addend);
 215   else if (r_type == R_MICROBLAZE_REL)
 216     *reloc_addr = map->l_addr + reloc->r_addend;
 217   else
 218     {
 219       const Elf32_Sym *const refsym = sym;
 220       struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
 221                                               r_type);
 222       Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
 223
 224       value += reloc->r_addend;
 225       if (r_type == R_MICROBLAZE_GLOB_DAT
 226           || r_type == R_MICROBLAZE_JUMP_SLOT
 227           || r_type == R_MICROBLAZE_32)
 228         {
 229           *reloc_addr = value;
 230         }
 231       else if (r_type == R_MICROBLAZE_COPY)
 232         {
 233           if (sym != NULL && (sym->st_size > refsym->st_size
 234               || (sym->st_size < refsym->st_size && GLRO (dl_verbose))) )
 235             {
 236               const char *strtab;
 237
 238               strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
 239               _dl_error_printf ("\
 240 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
 241                                 RTLD_PROGNAME, strtab + refsym->st_name);
 242             }
 243           memcpy (reloc_addr_arg, (void *) value,
 244                   MIN (sym->st_size, refsym->st_size));
 245         }
 246       else if (r_type == R_MICROBLAZE_NONE)
 247         {
 248         }
 249 #if !defined RTLD_BOOTSTRAP
 250       else if (r_type == R_MICROBLAZE_TLSDTPMOD32)
 251         {
 252           if (sym_map != NULL)
 253             *reloc_addr = sym_map->l_tls_modid;
 254         }
 255       else if (r_type == R_MICROBLAZE_TLSDTPREL32)
 256         {
 257           if (sym != NULL)
 258             *reloc_addr = sym->st_value + reloc->r_addend;
 259         }
 260       else if (r_type == R_MICROBLAZE_TLSTPREL32)
 261         {
 262           if (sym != NULL)
 263             {
 264               CHECK_STATIC_TLS (map, sym_map);
 265               *reloc_addr = sym->st_value + sym_map->l_tls_offset + reloc->r_addend;
 266             }
 267         }
 268 #endif
 269       else
 270         {
 271           _dl_reloc_bad_type (map, r_type, 0);
 272         }
 273     }
 274 }
 275
 276 static inline void
 277 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
 278                            void *const reloc_addr_arg)
 279 {
 280   Elf32_Addr *const reloc_addr = reloc_addr_arg;
 281   PUT_REL_64 (reloc_addr, l_addr + reloc->r_addend);
 282 }
 283
 284 static inline void
 285 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
 286                       Elf32_Addr l_addr, const Elf32_Rela *reloc,
 287                       int skip_ifunc)
 288 {
 289   Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
 290   if (ELF32_R_TYPE (reloc->r_info) == R_MICROBLAZE_JUMP_SLOT)
 291     *reloc_addr += l_addr;
 292   else
 293     _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
 294 }
 295
 296 #endif /* RESOLVE_MAP.  */