251 lines
8.2 KiB
C
251 lines
8.2 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. SPARC version.
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Copyright (C) 1996 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#define ELF_MACHINE_NAME "sparc"
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#include <assert.h>
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#include <string.h>
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#include <link.h>
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/* Some SPARC opcodes we need to use for self-modifying code. */
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#define OPCODE_NOP 0x01000000 /* nop */
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#define OPCODE_CALL 0x04000000 /* call ?; add PC-rel word address */
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#define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */
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#define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */
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#define OPCODE_SAVE_SP64 0x9de3bfc0 /* save %sp, -64, %sp */
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/* Return nonzero iff E_MACHINE is compatible with the running host. */
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static inline int
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elf_machine_matches_host (Elf32_Half e_machine)
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{
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switch (e_machine)
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{
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case EM_SPARC:
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return 1;
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default:
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return 0;
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}
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}
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/* Return the run-time address of the _GLOBAL_OFFSET_TABLE_.
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Must be inlined in a function which uses global data. */
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static inline Elf32_Addr *
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elf_machine_got (void)
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{
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register Elf32_Addr *got asm ("%l7");
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return got;
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf32_Addr
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elf_machine_load_address (void)
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{
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Elf32_Addr addr;
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???
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return addr;
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}
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/* The `subl' insn above will contain an R_68K_RELATIVE relocation
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entry intended to insert the run-time address of the label `here'.
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This will be the first relocation in the text of the dynamic
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linker; we skip it to avoid trying to modify read-only text in this
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early stage. */
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#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) \
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((dynamic_info)[DT_RELA]->d_un.d_ptr += sizeof (Elf32_Rela), \
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(dynamic_info)[DT_RELASZ]->d_un.d_val -= sizeof (Elf32_Rela))
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/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
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MAP is the object containing the reloc. */
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static inline void
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elf_machine_rela (struct link_map *map,
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const Elf32_Rela *reloc, const Elf32_Sym *sym,
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Elf32_Addr (*resolve) (const Elf32_Sym **ref,
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Elf32_Addr reloc_addr,
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int noplt))
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{
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Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset);
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Elf32_Addr loadbase;
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switch (ELF32_R_TYPE (reloc->r_info))
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{
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case R_SPARC_COPY:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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memcpy (reloc_addr, (void *) (loadbase + sym->st_value), sym->st_size);
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break;
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case R_SPARC_GLOB_DAT:
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case R_SPARC_32:
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loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
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/* RESOLVE is null during bootstrap relocation. */
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map->l_addr);
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*reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend);
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break;
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case R_SPARC_JMP_SLOT:
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loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 1) :
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/* RESOLVE is null during bootstrap relocation. */
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map->l_addr);
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{
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Elf32_Addr value = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend);
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reloc_addr[1] = OPCODE_SETHI | (value >> 10);
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reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff);
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}
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break;
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case R_SPARC_8:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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*(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend);
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break;
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case R_SPARC_16:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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*(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend);
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break;
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case R_SPARC_32:
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loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
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/* RESOLVE is null during bootstrap relocation. */
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map->l_addr);
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break;
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case R_SPARC_RELATIVE:
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*reloc_addr = map->l_addr + reloc->r_addend;
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break;
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case R_SPARC_DISP8:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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*(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend
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- (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_DISP16:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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*(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend
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- (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_DISP32:
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loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
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*reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
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+ reloc->r_addend
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- (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_NONE: /* Alright, Wilbur. */
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break;
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default:
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assert (! "unexpected dynamic reloc type");
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break;
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}
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}
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static inline void
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elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc)
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{
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switch (ELF32_R_TYPE (reloc->r_info))
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{
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case R_SPARC_NONE:
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break;
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case R_SPARC_JMP_SLOT:
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break;
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default:
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assert (! "unexpected PLT reloc type");
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break;
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}
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}
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/* Nonzero iff TYPE describes relocation of a PLT entry, so
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PLT entries should not be allowed to define the value. */
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#define elf_machine_pltrel_p(type) ((type) == R_SPARC_JMP_SLOT)
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/* The SPARC never uses Elf32_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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/* Set up the loaded object described by L so its unrelocated PLT
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entries will jump to the on-demand fixup code in dl-runtime.c. */
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static inline void
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elf_machine_runtime_setup (struct link_map *l, int lazy)
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{
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Elf32_Addr *plt;
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extern void _dl_runtime_resolve (Elf32_Word);
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if (l->l_info[DT_JMPREL] && lazy)
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{
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/* The entries for functions in the PLT have not yet been filled in.
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Their initial contents will arrange when called to set the high 22
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bits of %g1 with an offset into the .rela.plt section and jump to
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the beginning of the PLT. */
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plt = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr);
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/* The beginning of the PLT does:
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save %sp, -64, %sp
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pltpc: call _dl_runtime_resolve
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nop
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.word MAP
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This saves the register window containing the arguments, and the
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PC value (pltpc) implicitly saved in %o7 by the call points near the
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location where we store the link_map pointer for this object. */
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plt[0] = OPCODE_SAVE_SP64; /* save %sp, -64, %sp */
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/* Construct PC-relative word address. */
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plt[1] = OPCODE_CALL | (((Elf32_Addr) &_dl_runtime_resolve -
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(Elf32_Addr) &plt[1]) >> 2);
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plt[2] = OPCODE_NOP; /* Fill call delay slot. */
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plt[3] = l;
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}
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/* This code is used in dl-runtime.c to call the `fixup' function
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and then redirect to the address it returns. */
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
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| Trampoline for _dl_runtime_resolver
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.globl _dl_runtime_resolve
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.type _dl_runtime_resolve, @function
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_dl_runtime_resolve:
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| Pass two args to fixup: the PLT address computed from the PC saved
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| in the PLT's call insn, and the reloc offset passed in %g1.
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ld [%o7 + 8], %o1 | Second arg, loaded from PLTPC[2].
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call fixup
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shrl %g1, 22, %o0 | First arg, set in delay slot of call.
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| Jump to the real function.
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jmpl %o0, %g0
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| In the delay slot of that jump, restore the register window
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| saved by the first insn of the PLT.
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restore
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.size _dl_runtime_resolve, . - _dl_runtime_resolve
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");
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/* The PLT uses Elf32_Rela relocs. */
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#define elf_machine_relplt elf_machine_rela
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}
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/* Mask identifying addresses reserved for the user program,
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where the dynamic linker should not map anything. */
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#define ELF_MACHINE_USER_ADDRESS_MASK ???
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/* Initial entry point code for the dynamic linker.
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The C function `_dl_start' is the real entry point;
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its return value is the user program's entry point. */
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#define RTLD_START asm (???)
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