276 lines
8.4 KiB
C
276 lines
8.4 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. m68k 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. */
|
|
|
|
#ifndef dl_machine_h
|
|
#define dl_machine_h
|
|
|
|
#define ELF_MACHINE_NAME "m68k"
|
|
|
|
#include <assert.h>
|
|
|
|
/* 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_68K:
|
|
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 ("%a5");
|
|
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 ("here: lea here(%%pc), %0\n"
|
|
" sub.l %#here, %0"
|
|
: "=a" (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))
|
|
|
|
|
|
/* 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 *got;
|
|
extern void _dl_runtime_resolve (Elf32_Word);
|
|
|
|
if (l->l_info[DT_JMPREL] && lazy)
|
|
{
|
|
/* The GOT entries for functions in the PLT have not yet been
|
|
filled in. Their initial contents will arrange when called
|
|
to push an offset into the .rela.plt section, push
|
|
_GLOBAL_OFFSET_TABLE_[1], and then jump to
|
|
_GLOBAL_OFFSET_TABLE_[2]. */
|
|
got = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr);
|
|
got[1] = (Elf32_Addr) l; /* Identify this shared object. */
|
|
/* This function will get called to fix up the GOT entry
|
|
indicated by the offset on the stack, and then jump to the
|
|
resolved address. */
|
|
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
|
|
}
|
|
|
|
/* 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:
|
|
| Save %a0 (struct return address) and %a1.
|
|
move.l %a0, -(%sp)
|
|
move.l %a1, -(%sp)
|
|
| Call the real address resolver.
|
|
jbsr fixup
|
|
| Restore register %a0 and %a1.
|
|
move.l (%sp)+, %a1
|
|
move.l (%sp)+, %a0
|
|
| Pop parameters
|
|
addq.l #8, %sp
|
|
| Call real function.
|
|
jmp (%d0)
|
|
.size _dl_runtime_resolve, . - _dl_runtime_resolve
|
|
");
|
|
#define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0, long int save_a1
|
|
/* 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 0x80000000UL
|
|
|
|
/* 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
|
|
.globl _start
|
|
.globl _dl_start_user
|
|
_start:
|
|
move.l %sp, -(%sp)
|
|
jbsr _dl_start
|
|
addq.l #4, %sp
|
|
_dl_start_user:
|
|
| Save the user entry point address in %a4.
|
|
move.l %d0, %a4
|
|
| Point %a5 at the GOT.
|
|
lea _GLOBAL_OFFSET_TABLE_@GOTPC(%pc), %a5
|
|
| See if we were run as a command with the executable file
|
|
| name as an extra leading argument.
|
|
move.l ([_dl_skip_args@GOT, %a5]), %d0
|
|
jeq 0f
|
|
| Pop the original argument count
|
|
move.l (%sp)+, %d1
|
|
| Subtract _dl_skip_args from it.
|
|
sub.l %d0, %d1
|
|
| Adjust the stack pointer to skip _dl_skip_args words.
|
|
lea (%sp, %d0*4), %sp
|
|
| Push back the modified argument count.
|
|
move.l %d1, -(%sp)
|
|
0: | Push _dl_default_scope[2] as argument in _dl_init_next call below.
|
|
move.l ([_dl_default_scope@GOT, %a5], 8), %d2
|
|
0: move.l %d2, -(%sp)
|
|
| Call _dl_init_next to return the address of an initializer
|
|
| function to run.
|
|
bsr.l _dl_init_next@PLTPC
|
|
add.l #4, %sp | Pop argument.
|
|
| Check for zero return, when out of initializers.
|
|
tst.l %d0
|
|
jeq 1f
|
|
| Call the shared object initializer function.
|
|
| NOTE: We depend only on the registers (%d2, %a4 and %a5)
|
|
| and the return address pushed by this call;
|
|
| the initializer is called with the stack just
|
|
| as it appears on entry, and it is free to move
|
|
| the stack around, as long as it winds up jumping to
|
|
| the return address on the top of the stack.
|
|
move.l %d0, %a0
|
|
jsr (%a0)
|
|
| Loop to call _dl_init_next for the next initializer.
|
|
jra 0b
|
|
1: | Clear the startup flag.
|
|
clr.l _dl_starting_up@GOT(%a5)
|
|
| Pass our finalizer function to the user in %a1.
|
|
move.l _dl_fini@GOT(%a5), %a1
|
|
| Initialize %fp with the stack pointer.
|
|
move.l %sp, %fp
|
|
| Jump to the user's entry point.
|
|
jmp (%a4)");
|
|
|
|
/* Nonzero iff TYPE describes a relocation that should
|
|
skip the executable when looking up the symbol value. */
|
|
#define elf_machine_lookup_noexec_p(type) ((type) == R_68K_COPY)
|
|
|
|
/* Nonzero iff TYPE describes relocation of a PLT entry, so
|
|
PLT entries should not be allowed to define the value. */
|
|
#define elf_machine_lookup_noplt_p(type) ((type) == R_68K_JMP_SLOT)
|
|
|
|
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
|
|
#define ELF_MACHINE_RELOC_NOPLT R_68K_JMP_SLOT
|
|
|
|
/* The m68k never uses Elf32_Rel relocations. */
|
|
#define ELF_MACHINE_NO_REL 1
|
|
|
|
#endif /* !dl_machine_h */
|
|
|
|
#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);
|
|
|
|
if (ELF32_R_TYPE (reloc->r_info) == R_68K_RELATIVE)
|
|
*reloc_addr = map->l_addr + reloc->r_addend;
|
|
else
|
|
{
|
|
Elf32_Addr value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
|
|
if (sym)
|
|
value += sym->st_value;
|
|
|
|
switch (ELF32_R_TYPE (reloc->r_info))
|
|
{
|
|
case R_68K_COPY:
|
|
memcpy (reloc_addr, (void *) value, sym->st_size);
|
|
break;
|
|
case R_68K_GLOB_DAT:
|
|
case R_68K_JMP_SLOT:
|
|
*reloc_addr = value;
|
|
break;
|
|
case R_68K_8:
|
|
*(char *) reloc_addr = value + reloc->r_addend;
|
|
break;
|
|
case R_68K_16:
|
|
*(short *) reloc_addr = value + reloc->r_addend;
|
|
break;
|
|
case R_68K_32:
|
|
*reloc_addr = value + reloc->r_addend;
|
|
break;
|
|
case R_68K_PC8:
|
|
*(char *) reloc_addr
|
|
= value + reloc->r_addend - (Elf32_Addr) reloc_addr;
|
|
break;
|
|
case R_68K_PC16:
|
|
*(short *) reloc_addr
|
|
= value + reloc->r_addend - (Elf32_Addr) reloc_addr;
|
|
break;
|
|
case R_68K_PC32:
|
|
*reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr;
|
|
break;
|
|
case R_68K_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)
|
|
{
|
|
Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset);
|
|
switch (ELF32_R_TYPE (reloc->r_info))
|
|
{
|
|
case R_68K_JMP_SLOT:
|
|
*reloc_addr += map->l_addr;
|
|
break;
|
|
default:
|
|
assert (! "unexpected PLT reloc type");
|
|
break;
|
|
}
|
|
}
|
|
|
|
#endif /* RESOLVE */
|