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/* Machine-dependent ELF dynamic relocation inline functions. SPARC version.
Copyright (C) 1996 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 <assert.h>
#include <string.h>
#include <link.h>
/* Some SPARC opcodes we need to use for self-modifying code. */
#define OPCODE_NOP 0x01000000 /* nop */
#define OPCODE_CALL 0x04000000 /* 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)
{
switch (e_machine)
{
case EM_SPARC:
return 1;
default:
return 0;
}
}
/* 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;
???
return addr;
}
/* The `subl' insn above will contain an R_68K_RELATIVE relocation
entry intended to insert the run-time address of the label `here'.
This will be the first relocation in the text of the dynamic
linker; we skip it to avoid trying to modify read-only text in this
early stage. */
#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) \
((dynamic_info)[DT_RELA]->d_un.d_ptr += sizeof (Elf32_Rela), \
(dynamic_info)[DT_RELASZ]->d_un.d_val -= sizeof (Elf32_Rela))
/* 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,
Elf32_Addr (*resolve) (const Elf32_Sym **ref,
Elf32_Addr reloc_addr,
int noplt))
{
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, (Elf32_Addr) reloc_addr, 0);
memcpy (reloc_addr, (void *) (loadbase + sym->st_value), sym->st_size);
break;
case R_SPARC_GLOB_DAT:
case R_SPARC_32:
loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
/* RESOLVE is null during bootstrap relocation. */
map->l_addr);
*reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
+ reloc->r_addend);
break;
case R_SPARC_JMP_SLOT:
loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 1) :
/* RESOLVE is null during bootstrap relocation. */
map->l_addr);
{
Elf32_Addr value = ((sym ? (loadbase + sym->st_value) : 0)
+ reloc->r_addend);
reloc_addr[1] = OPCODE_SETHI | (value >> 10);
reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff);
}
break;
case R_SPARC_8:
loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
*(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
+ reloc->r_addend);
break;
case R_SPARC_16:
loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
*(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
+ reloc->r_addend);
break;
case R_SPARC_32:
loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
/* RESOLVE is null during bootstrap relocation. */
map->l_addr);
break;
case R_SPARC_RELATIVE:
*reloc_addr = map->l_addr + reloc->r_addend;
break;
case R_SPARC_DISP8:
loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 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, (Elf32_Addr) reloc_addr, 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, (Elf32_Addr) reloc_addr, 0);
*reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
+ reloc->r_addend
- (Elf32_Addr) reloc_addr);
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;
}
}
/* 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] = 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:
| 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 (???)
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