mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-24 11:41:07 +00:00
34b402e5a9
1997-03-24 19:58 Richard Henderson <rth@tamu.edu> * stdlib/tst-strtol.c (tests): Correct 64-bit entry. * sysdeps/alpha/bsd-_setjmp.S: Alias _setjmp to __setjmp for change to tst-setjmp.c. * sysdeps/alpha/dl-machine.h: Mirror Roland's recent changes. * sysdeps/i386/dl-machine.h: Correct noexec_p comment. * sysdeps/sparc/dl-machine.h: Likewise. * sysdeps/libm-ieee754/s_remquo.c: Rename {hp,lp} -> {hy,ly}. Add missing qs variable. * sysdeps/libm-ieee754/s_remquof.c: Likewise.
320 lines
10 KiB
C
320 lines
10 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. i386 version.
|
|
Copyright (C) 1995, 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 "i386"
|
|
|
|
#include <assert.h>
|
|
|
|
/* Return nonzero iff E_MACHINE is compatible with the running host. */
|
|
static inline int __attribute__ ((unused))
|
|
elf_machine_matches_host (Elf32_Half e_machine)
|
|
{
|
|
switch (e_machine)
|
|
{
|
|
case EM_386:
|
|
case EM_486:
|
|
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 ("%ebx");
|
|
return *got;
|
|
}
|
|
|
|
|
|
/* Return the run-time load address of the shared object. */
|
|
static inline Elf32_Addr __attribute__ ((unused))
|
|
elf_machine_load_address (void)
|
|
{
|
|
Elf32_Addr addr;
|
|
asm (" call here\n"
|
|
"here: popl %0\n"
|
|
" subl $here, %0"
|
|
: "=r" (addr));
|
|
return addr;
|
|
}
|
|
/* The `subl' insn above will contain an R_386_32 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) \
|
|
++(const Elf32_Rel *) (dynamic_info)[DT_REL]->d_un.d_ptr; \
|
|
(dynamic_info)[DT_RELSZ]->d_un.d_val -= sizeof (Elf32_Rel);
|
|
|
|
|
|
#ifndef PROF
|
|
/* We add a declaration of this function here so that in dl-runtime.c
|
|
the ELF_MACHINE_RUNTIME_TRAMPOLINE macro really can pass the parameters
|
|
in registers.
|
|
|
|
We cannot use this scheme for profiling because the _mcount call
|
|
destroys the passed register information. */
|
|
static ElfW(Addr) fixup (struct link_map *l, ElfW(Word) reloc_offset)
|
|
__attribute__ ((regparm (2), unused));
|
|
#endif
|
|
|
|
/* 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 __attribute__ ((unused))
|
|
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 .rel.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. */
|
|
#ifndef PROF
|
|
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
|
|
.globl _dl_runtime_resolve
|
|
.type _dl_runtime_resolve, @function
|
|
_dl_runtime_resolve:
|
|
pushl %eax # Preserve registers otherwise clobbered.
|
|
pushl %ecx
|
|
pushl %edx
|
|
movl 16(%esp), %edx # Copy args pushed by PLT in register. Note
|
|
movl 12(%esp), %eax # that `fixup' takes its parameters in regs.
|
|
call fixup # Call resolver.
|
|
popl %edx # Get register content back.
|
|
popl %ecx
|
|
xchgl %eax, (%esp) # Get %eax contents end store function address.
|
|
ret $8 # Jump to function address.
|
|
.size _dl_runtime_resolve, .-_dl_runtime_resolve
|
|
");
|
|
#else
|
|
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
|
|
.globl _dl_runtime_resolve
|
|
.type _dl_runtime_resolve, @function
|
|
_dl_runtime_resolve:
|
|
pushl %eax # Preserve registers otherwise clobbered.
|
|
pushl %ecx
|
|
pushl %edx
|
|
movl 16(%esp), %edx # Push the arguments for `fixup'
|
|
movl 12(%esp), %eax
|
|
pushl %edx
|
|
pushl %eax
|
|
call fixup # Call resolver.
|
|
popl %edx # Pop the parameters
|
|
popl %ecx
|
|
popl %edx # Get register content back.
|
|
popl %ecx
|
|
xchgl %eax, (%esp) # Get %eax contents end store function address.
|
|
ret $8 # Jump to function address.
|
|
.size _dl_runtime_resolve, .-_dl_runtime_resolve
|
|
");
|
|
#endif
|
|
/* The PLT uses Elf32_Rel relocs. */
|
|
#define elf_machine_relplt elf_machine_rel
|
|
}
|
|
|
|
/* Mask identifying addresses reserved for the user program,
|
|
where the dynamic linker should not map anything. */
|
|
#define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
|
|
|
|
|
|
|
|
/* 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\
|
|
.globl _dl_start_user\n\
|
|
_start:\n\
|
|
pushl %esp\n\
|
|
call _dl_start\n\
|
|
popl %ebx\n\
|
|
_dl_start_user:\n\
|
|
# Save the user entry point address in %edi.\n\
|
|
movl %eax, %edi\n\
|
|
# Point %ebx at the GOT.
|
|
call 0f\n\
|
|
0: popl %ebx\n\
|
|
addl $_GLOBAL_OFFSET_TABLE_+[.-0b], %ebx\n\
|
|
# See if we were run as a command with the executable file\n\
|
|
# name as an extra leading argument.\n\
|
|
movl _dl_skip_args@GOT(%ebx), %eax\n\
|
|
movl (%eax), %eax\n\
|
|
# Pop the original argument count.\n\
|
|
popl %ecx\n\
|
|
# Subtract _dl_skip_args from it.\n\
|
|
subl %eax, %ecx\n\
|
|
# Adjust the stack pointer to skip _dl_skip_args words.\n\
|
|
leal (%esp,%eax,4), %esp\n\
|
|
# Push back the modified argument count.\n\
|
|
pushl %ecx\n\
|
|
# Push _dl_default_scope[2] as argument in _dl_init_next call below.\n\
|
|
movl _dl_default_scope@GOT(%ebx), %eax\n\
|
|
movl 8(%eax), %esi\n\
|
|
0: pushl %esi\n\
|
|
# Call _dl_init_next to return the address of an initializer\n\
|
|
# function to run.\n\
|
|
call _dl_init_next@PLT\n\
|
|
addl $4, %esp # Pop argument.\n\
|
|
# Check for zero return, when out of initializers.\n\
|
|
testl %eax, %eax\n\
|
|
jz 1f\n\
|
|
# Call the shared object initializer function.\n\
|
|
# NOTE: We depend only on the registers (%ebx, %esi and %edi)\n\
|
|
# and the return address pushed by this call;\n\
|
|
# the initializer is called with the stack just\n\
|
|
# as it appears on entry, and it is free to move\n\
|
|
# the stack around, as long as it winds up jumping to\n\
|
|
# the return address on the top of the stack.\n\
|
|
call *%eax\n\
|
|
# Loop to call _dl_init_next for the next initializer.\n\
|
|
jmp 0b\n\
|
|
1: # Clear the startup flag.\n\
|
|
movl _dl_starting_up@GOT(%ebx), %eax\n\
|
|
movl $0, (%eax)\n\
|
|
# Pass our finalizer function to the user in %edx, as per ELF ABI.\n\
|
|
movl _dl_fini@GOT(%ebx), %edx\n\
|
|
# Jump to the user's entry point.\n\
|
|
jmp *%edi\n\
|
|
");
|
|
|
|
/* Nonzero iff TYPE should not be allowed to resolve to one of
|
|
the main executable's symbols, as for a COPY reloc. */
|
|
#define elf_machine_lookup_noexec_p(type) ((type) == R_386_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_386_JMP_SLOT)
|
|
|
|
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
|
|
#define ELF_MACHINE_RELOC_NOPLT R_386_JMP_SLOT
|
|
|
|
/* The i386 never uses Elf32_Rela relocations. */
|
|
#define ELF_MACHINE_NO_RELA 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_rel (struct link_map *map, const Elf32_Rel *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_386_RELATIVE)
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
if (map != &_dl_rtld_map) /* Already done in rtld itself. */
|
|
#endif
|
|
*reloc_addr += map->l_addr;
|
|
}
|
|
else
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
const Elf32_Sym *const refsym = sym;
|
|
#endif
|
|
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_386_COPY:
|
|
memcpy (reloc_addr, (void *) value, sym->st_size);
|
|
break;
|
|
case R_386_GLOB_DAT:
|
|
case R_386_JMP_SLOT:
|
|
*reloc_addr = value;
|
|
break;
|
|
case R_386_32:
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
/* This is defined in rtld.c, but nowhere in the static
|
|
libc.a; make the reference weak so static programs can
|
|
still link. This declaration cannot be done when
|
|
compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because
|
|
rtld.c contains the common defn for _dl_rtld_map, which
|
|
is incompatible with a weak decl in the same file. */
|
|
weak_extern (_dl_rtld_map);
|
|
if (map == &_dl_rtld_map)
|
|
/* Undo the relocation done here during bootstrapping.
|
|
Now we will relocate it anew, possibly using a
|
|
binding found in the user program or a loaded library
|
|
rather than the dynamic linker's built-in definitions
|
|
used while loading those libraries. */
|
|
value -= map->l_addr + refsym->st_value;
|
|
#endif
|
|
*reloc_addr += value;
|
|
break;
|
|
}
|
|
case R_386_PC32:
|
|
*reloc_addr += (value - (Elf32_Addr) reloc_addr);
|
|
break;
|
|
case R_386_NONE: /* Alright, Wilbur. */
|
|
break;
|
|
default:
|
|
assert (! "unexpected dynamic reloc type");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
elf_machine_lazy_rel (struct link_map *map, const Elf32_Rel *reloc)
|
|
{
|
|
Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset);
|
|
switch (ELF32_R_TYPE (reloc->r_info))
|
|
{
|
|
case R_386_JMP_SLOT:
|
|
*reloc_addr += map->l_addr;
|
|
break;
|
|
default:
|
|
assert (! "unexpected PLT reloc type");
|
|
break;
|
|
}
|
|
}
|
|
|
|
#endif /* RESOLVE */
|