/* Machine-dependent ELF dynamic relocation inline functions. SPARC version. Copyright (C) 1996, 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define ELF_MACHINE_NAME "sparc" #include #include #include /* Some SPARC opcodes we need to use for self-modifying code. */ #define OPCODE_NOP 0x01000000 /* nop */ #define OPCODE_CALL 0x40000000 /* call ?; add PC-rel word address */ #define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */ #define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */ #define OPCODE_SAVE_SP64 0x9de3bfc0 /* save %sp, -64, %sp */ /* Return nonzero iff E_MACHINE is compatible with the running host. */ static inline int elf_machine_matches_host (Elf32_Half e_machine) { return e_machine == EM_SPARC; } /* Return the link-time address of _DYNAMIC. Conveniently, this is the first element of the GOT. This must be inlined in a function which uses global data. */ static inline Elf32_Addr elf_machine_dynamic (void) { register Elf32_Addr *got asm ("%l7"); return *got; } /* Return the run-time load address of the shared object. */ static inline Elf32_Addr elf_machine_load_address (void) { Elf32_Addr addr; asm ( "add %%fp,0x44,%%o2\n\t" /* o2 = point to argc */ "ld [%%o2 - 4],%%o0\n\t" /* o0 = load argc */ "sll %%o0, 2, %%o0\n\t" /* o0 = argc * sizeof (int) */ "add %%o2,%%o0,%%o2\n\t" /* o2 = skip over argv */ "add %%o2,4,%%o2\n\t" /* skip over null after argv */ /* Now %o2 is pointing to env, skip over that as well. */ "1:\n\t" "ld [%%o2],%%o0\n\t" "cmp %%o0,0\n\t" "bnz 1b\n\t" "add %%o2,4,%%o2\n\t" /* Note that above, we want to advance the NULL after envp so we always add 4. */ /* Now, search for the AT_BASE property. */ "2:\n\t" "ld [%%o2],%%o0\n\t" "cmp %%o0,0\n\t" "be,a 3f\n\t" "or %%g0,%%g0,%0\n\t" "cmp %%o0,7\n\t" /* AT_BASE = 7 */ "be,a 3f\n\t" "ld [%%o2+4],%0\n\t" "b 2b\n\t" "add %%o2,8,%%o2\n\t" /* At this point %0 has the load address for the interpreter */ "3:\n\t" : "=r" (addr) : /* no inputs */ : "o0", "o2"); return addr; } #ifdef RESOLVE /* Perform the relocation specified by RELOC and SYM (which is fully resolved). MAP is the object containing the reloc. */ static inline void elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, const Elf32_Sym *sym, const struct r_found_version *version) { Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset); Elf32_Addr loadbase; switch (ELF32_R_TYPE (reloc->r_info)) { case R_SPARC_COPY: loadbase = RESOLVE (&sym, version, DL_LOOKUP_NOEXEC); memcpy (reloc_addr, (void *) (loadbase + sym->st_value), sym->st_size); break; case R_SPARC_GLOB_DAT: case R_SPARC_32: loadbase = RESOLVE (&sym, version, 0); *reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend); break; case R_SPARC_JMP_SLOT: loadbase = RESOLVE (&sym, version, DL_LOOKUP_NOPLT); { Elf32_Addr value = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend); reloc_addr[1] = OPCODE_SETHI_G1 | (value >> 10); reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff); } break; case R_SPARC_8: loadbase = RESOLVE (&sym, version, 0); *(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend); break; case R_SPARC_16: loadbase = RESOLVE (&sym, version, 0); *(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend); break; case R_SPARC_RELATIVE: *reloc_addr += map->l_addr + reloc->r_addend; break; case R_SPARC_DISP8: loadbase = RESOLVE (&sym, version, 0); *(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend - (Elf32_Addr) reloc_addr); break; case R_SPARC_DISP16: loadbase = RESOLVE (&sym, version, 0); *(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend - (Elf32_Addr) reloc_addr); break; case R_SPARC_DISP32: loadbase = RESOLVE (&sym, version, 0); *reloc_addr = ((sym ? (loadbase + sym->st_value) : 0) + reloc->r_addend - (Elf32_Addr) reloc_addr); break; case R_SPARC_LO10: { unsigned int saddr; loadbase = RESOLVE (&sym, version, 0); saddr = (loadbase ? loadbase : map->l_addr) + reloc->r_addend; *reloc_addr = (*reloc_addr & ~0x3ff) | (saddr & 0x3ff); } break; case R_SPARC_WDISP30: { unsigned int saddr; loadbase = RESOLVE (&sym, version, 0); saddr = (loadbase ? loadbase : map->l_addr) + reloc->r_addend; *reloc_addr = ((*reloc_addr & 0xc0000000) | ((saddr - (unsigned int) reloc_addr)>>2)); } break; case R_SPARC_HI22: { unsigned int saddr; loadbase = RESOLVE (&sym, version, 0); saddr = (loadbase ? loadbase : map->l_addr) + reloc->r_addend; *reloc_addr = (*reloc_addr & 0xffc00000)|(saddr >> 10); } break; case R_SPARC_NONE: /* Alright, Wilbur. */ break; default: assert (! "unexpected dynamic reloc type"); break; } } static inline void elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc) { switch (ELF32_R_TYPE (reloc->r_info)) { case R_SPARC_NONE: break; case R_SPARC_JMP_SLOT: break; default: assert (! "unexpected PLT reloc type"); break; } } #endif /* RESOLVE */ /* Nonzero iff TYPE describes relocation of a PLT entry, so PLT entries should not be allowed to define the value. */ #define elf_machine_pltrel_p(type) ((type) == R_SPARC_JMP_SLOT) /* The SPARC never uses Elf32_Rel relocations. */ #define ELF_MACHINE_NO_REL 1 /* Set up the loaded object described by L so its unrelocated PLT entries will jump to the on-demand fixup code in dl-runtime.c. */ static inline void elf_machine_runtime_setup (struct link_map *l, int lazy) { Elf32_Addr *plt; extern void _dl_runtime_resolve (Elf32_Word); if (l->l_info[DT_JMPREL] && lazy) { /* The entries for functions in the PLT have not yet been filled in. Their initial contents will arrange when called to set the high 22 bits of %g1 with an offset into the .rela.plt section and jump to the beginning of the PLT. */ plt = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr); /* The beginning of the PLT does: save %sp, -64, %sp pltpc: call _dl_runtime_resolve nop .word MAP This saves the register window containing the arguments, and the PC value (pltpc) implicitly saved in %o7 by the call points near the location where we store the link_map pointer for this object. */ plt[0] = OPCODE_SAVE_SP64; /* save %sp, -64, %sp */ /* Construct PC-relative word address. */ plt[1] = OPCODE_CALL | (((Elf32_Addr) &_dl_runtime_resolve - (Elf32_Addr) &plt[1]) >> 2); plt[2] = OPCODE_NOP; /* Fill call delay slot. */ plt[3] = (Elf32_Addr *) l; } /* This code is used in dl-runtime.c to call the `fixup' function and then redirect to the address it returns. */ #define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ # Trampoline for _dl_runtime_resolver .globl _dl_runtime_resolve .type _dl_runtime_resolve, @function _dl_runtime_resolve: t 1 #call %g0 # Pass two args to fixup: the PLT address computed from the PC saved # in the PLT's call insn, and the reloc offset passed in %g1. #ld [%o7 + 8], %o1 | Second arg, loaded from PLTPC[2]. #call fixup #shrl %g1, 22, %o0 | First arg, set in delay slot of call. # Jump to the real function. #jmpl %o0, %g0 # In the delay slot of that jump, restore the register window # saved by the first insn of the PLT. #restore .size _dl_runtime_resolve, . - _dl_runtime_resolve "); /* The PLT uses Elf32_Rela relocs. */ #define elf_machine_relplt elf_machine_rela } /* Mask identifying addresses reserved for the user program, where the dynamic linker should not map anything. */ #define ELF_MACHINE_USER_ADDRESS_MASK ??? /* Initial entry point code for the dynamic linker. The C function `_dl_start' is the real entry point; its return value is the user program's entry point. */ #define RTLD_START __asm__ ( \ ".text\n\ .globl _start\n\ .type _start,@function\n\ _start:\n\ /* Pass pointer to argument block to _dl_start. */\n\ add %sp,64,%o0\n\ call _dl_start\n\ nop\n\ \n\ mov %o0,%l0\n\ \n\ 2:\n\ call 1f\n\ nop\n\ 1:\n\ sethi %hi(_GLOBAL_OFFSET_TABLE_-(2b-.)),%l2\n\ sethi %hi(_dl_default_scope),%l3\n\ or %l2,%lo(_GLOBAL_OFFSET_TABLE_-(2b-.)),%l2\n\ or %l3,%lo(_dl_default_scope),%l3\n\ add %o7,%l2,%l1\n\ # %l1 has the GOT. %l3 has _dl_default_scope offset\n\ # Now, load _dl_default_scope [2]\n\ add %l3,4,%l3\n\ ld [%l1+%l3],%l4\n\ # %l4 has _dl_default_scope [2]\n\ # call _dl_init_next until it returns 0, pass _dl_default_scope [2]\n\ 3:\n\ call _dl_init_next\n\ mov %l4,%o0\n\ cmp %o0,%g0\n\ bz,a 4f\n\ nop\n\ call %o0\n\ nop\n\ b,a 3b\n\ 4:\n\ # Clear the _dl_starting_up variable and pass _dl_fini in %g1 as per ELF ABI.\n\ sethi %hi(_dl_starting_up),%l4\n\ sethi %hi(_dl_fini),%l3\n\ or %l4,%lo(_dl_starting_up),%l4\n\ or %l3,%lo(_dl_fini),%l3\n\ # clear _dl_starting_up\n\ ld [%l1+%l4],%l5\n\ st %g0,[%l5]\n\ # load out fini function for atexit in %g1\n\ ld [%l3+%l1],%g1\n\ # jump to the user program entry point.\n\ jmpl %l0,%g0\n\ nop\n\ ");