1f25bddd62
2005-01-25 Ulrich Drepper <drepper@redhat.com> * sysdeps/i386/dl-machine.h (elf_machine_rel): Remove code using RESOLVE. * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Remove code using RESOLVE. * elf/rtld.c (_dl_start): Remove RESOLVE definition.
440 lines
14 KiB
C
440 lines
14 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. x86-64 version.
|
|
Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Andreas Jaeger <aj@suse.de>.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; 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 "x86_64"
|
|
|
|
#include <sys/param.h>
|
|
#include <sysdep.h>
|
|
#include <tls.h>
|
|
|
|
/* Return nonzero iff ELF header is compatible with the running host. */
|
|
static inline int __attribute__ ((unused))
|
|
elf_machine_matches_host (const Elf64_Ehdr *ehdr)
|
|
{
|
|
return ehdr->e_machine == EM_X86_64;
|
|
}
|
|
|
|
|
|
/* 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 Elf64_Addr __attribute__ ((unused))
|
|
elf_machine_dynamic (void)
|
|
{
|
|
Elf64_Addr addr;
|
|
|
|
/* This works because we have our GOT address available in the small PIC
|
|
model. */
|
|
addr = (Elf64_Addr) &_DYNAMIC;
|
|
|
|
return addr;
|
|
}
|
|
|
|
|
|
/* Return the run-time load address of the shared object. */
|
|
static inline Elf64_Addr __attribute__ ((unused))
|
|
elf_machine_load_address (void)
|
|
{
|
|
register Elf64_Addr addr, tmp;
|
|
|
|
/* The easy way is just the same as on x86:
|
|
leaq _dl_start, %0
|
|
leaq _dl_start(%%rip), %1
|
|
subq %0, %1
|
|
but this does not work with binutils since we then have
|
|
a R_X86_64_32S relocation in a shared lib.
|
|
|
|
Instead we store the address of _dl_start in the data section
|
|
and compare it with the current value that we can get via
|
|
an RIP relative addressing mode. */
|
|
|
|
asm ("movq 1f(%%rip), %1\n"
|
|
"0:\tleaq _dl_start(%%rip), %0\n\t"
|
|
"subq %1, %0\n\t"
|
|
".section\t.data\n"
|
|
"1:\t.quad _dl_start\n\t"
|
|
".previous\n\t"
|
|
: "=r" (addr), "=r" (tmp) : : "cc");
|
|
|
|
return addr;
|
|
}
|
|
|
|
/* 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 int __attribute__ ((unused, always_inline))
|
|
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
|
|
{
|
|
Elf64_Addr *got;
|
|
extern void _dl_runtime_resolve (Elf64_Word) attribute_hidden;
|
|
extern void _dl_runtime_profile (Elf64_Word) attribute_hidden;
|
|
|
|
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 = (Elf64_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
|
|
/* If a library is prelinked but we have to relocate anyway,
|
|
we have to be able to undo the prelinking of .got.plt.
|
|
The prelinker saved us here address of .plt + 0x16. */
|
|
if (got[1])
|
|
{
|
|
l->l_mach.plt = got[1] + l->l_addr;
|
|
l->l_mach.gotplt = (Elf64_Addr) &got[3];
|
|
}
|
|
got[1] = (Elf64_Addr) l; /* Identify this shared object. */
|
|
|
|
/* The got[2] entry contains the address of a function which gets
|
|
called to get the address of a so far unresolved function and
|
|
jump to it. The profiling extension of the dynamic linker allows
|
|
to intercept the calls to collect information. In this case we
|
|
don't store the address in the GOT so that all future calls also
|
|
end in this function. */
|
|
if (__builtin_expect (profile, 0))
|
|
{
|
|
got[2] = (Elf64_Addr) &_dl_runtime_profile;
|
|
|
|
if (GLRO(dl_profile) != NULL
|
|
&& _dl_name_match_p (GLRO(dl_profile), l))
|
|
/* This is the object we are looking for. Say that we really
|
|
want profiling and the timers are started. */
|
|
GL(dl_profile_map) = l;
|
|
}
|
|
else
|
|
/* 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] = (Elf64_Addr) &_dl_runtime_resolve;
|
|
}
|
|
|
|
return lazy;
|
|
}
|
|
|
|
/* 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 ("\n\
|
|
.text\n\
|
|
.align 16\n\
|
|
.globl _start\n\
|
|
.globl _dl_start_user\n\
|
|
_start:\n\
|
|
movq %rsp, %rdi\n\
|
|
call _dl_start\n\
|
|
_dl_start_user:\n\
|
|
# Save the user entry point address in %r12.\n\
|
|
movq %rax, %r12\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(%rip), %eax\n\
|
|
# Pop the original argument count.\n\
|
|
popq %rdx\n\
|
|
# Adjust the stack pointer to skip _dl_skip_args words.\n\
|
|
leaq (%rsp,%rax,8), %rsp\n\
|
|
# Subtract _dl_skip_args from argc.\n\
|
|
subl %eax, %edx\n\
|
|
# Push argc back on the stack.\n\
|
|
pushq %rdx\n\
|
|
# Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
|
|
# argc -> rsi\n\
|
|
movq %rdx, %rsi\n\
|
|
# Save %rsp value in %r13.\n\
|
|
movq %rsp, %r13\n\
|
|
# And align stack for the _dl_init_internal call. \n\
|
|
andq $-16, %rsp\n\
|
|
# _dl_loaded -> rdi\n\
|
|
movq _rtld_local(%rip), %rdi\n\
|
|
# env -> rcx\n\
|
|
leaq 16(%r13,%rdx,8), %rcx\n\
|
|
# argv -> rdx\n\
|
|
leaq 8(%r13), %rdx\n\
|
|
# Clear %rbp to mark outermost frame obviously even for constructors.\n\
|
|
xorq %rbp, %rbp\n\
|
|
# Call the function to run the initializers.\n\
|
|
call _dl_init_internal@PLT\n\
|
|
# Pass our finalizer function to the user in %rdx, as per ELF ABI.\n\
|
|
leaq _dl_fini(%rip), %rdx\n\
|
|
# And make sure %rsp points to argc stored on the stack.\n\
|
|
movq %r13, %rsp\n\
|
|
# Jump to the user's entry point.\n\
|
|
jmp *%r12\n\
|
|
.previous\n\
|
|
");
|
|
|
|
/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
|
|
TLS variable, so undefined references should not be allowed to
|
|
define the value.
|
|
ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
|
|
of the main executable's symbols, as for a COPY reloc. */
|
|
#if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD)
|
|
# define elf_machine_type_class(type) \
|
|
((((type) == R_X86_64_JUMP_SLOT \
|
|
|| (type) == R_X86_64_DTPMOD64 \
|
|
|| (type) == R_X86_64_DTPOFF64 || (type) == R_X86_64_TPOFF64) \
|
|
* ELF_RTYPE_CLASS_PLT) \
|
|
| (((type) == R_X86_64_COPY) * ELF_RTYPE_CLASS_COPY))
|
|
#else
|
|
# define elf_machine_type_class(type) \
|
|
((((type) == R_X86_64_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT) \
|
|
| (((type) == R_X86_64_COPY) * ELF_RTYPE_CLASS_COPY))
|
|
#endif
|
|
|
|
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
|
|
#define ELF_MACHINE_JMP_SLOT R_X86_64_JUMP_SLOT
|
|
|
|
/* The x86-64 never uses Elf64_Rel relocations. */
|
|
#define ELF_MACHINE_NO_REL 1
|
|
|
|
/* We define an initialization functions. This is called very early in
|
|
_dl_sysdep_start. */
|
|
#define DL_PLATFORM_INIT dl_platform_init ()
|
|
|
|
static inline void __attribute__ ((unused))
|
|
dl_platform_init (void)
|
|
{
|
|
if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
|
|
/* Avoid an empty string which would disturb us. */
|
|
GLRO(dl_platform) = NULL;
|
|
}
|
|
|
|
static inline Elf64_Addr
|
|
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
|
|
const Elf64_Rela *reloc,
|
|
Elf64_Addr *reloc_addr, Elf64_Addr value)
|
|
{
|
|
return *reloc_addr = value;
|
|
}
|
|
|
|
/* Return the final value of a plt relocation. On x86-64 the
|
|
JUMP_SLOT relocation ignores the addend. */
|
|
static inline Elf64_Addr
|
|
elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
|
|
Elf64_Addr value)
|
|
{
|
|
return value;
|
|
}
|
|
|
|
|
|
/* Names of the architecture-specific auditing callback functions. */
|
|
#define ARCH_LA_PLTENTER x86_64_gnu_pltenter
|
|
#define ARCH_LA_PLTEXIT x86_64_gnu_pltexit
|
|
|
|
#endif /* !dl_machine_h */
|
|
|
|
#ifdef RESOLVE_MAP
|
|
|
|
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
|
|
MAP is the object containing the reloc. */
|
|
|
|
auto inline void
|
|
__attribute__ ((always_inline))
|
|
elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
|
|
const Elf64_Sym *sym, const struct r_found_version *version,
|
|
void *const reloc_addr_arg)
|
|
{
|
|
Elf64_Addr *const reloc_addr = reloc_addr_arg;
|
|
const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
|
|
|
|
#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
|
|
if (__builtin_expect (r_type == R_X86_64_RELATIVE, 0))
|
|
{
|
|
# if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
|
|
/* 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. */
|
|
# ifndef SHARED
|
|
weak_extern (GL(dl_rtld_map));
|
|
# endif
|
|
if (map != &GL(dl_rtld_map)) /* Already done in rtld itself. */
|
|
# endif
|
|
*reloc_addr = map->l_addr + reloc->r_addend;
|
|
}
|
|
else
|
|
#endif
|
|
if (__builtin_expect (r_type == R_X86_64_NONE, 0))
|
|
return;
|
|
else
|
|
{
|
|
#ifndef RTLD_BOOTSTRAP
|
|
const Elf64_Sym *const refsym = sym;
|
|
#endif
|
|
struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
|
|
Elf64_Addr value = (sym == NULL ? 0
|
|
: (Elf64_Addr) sym_map->l_addr + sym->st_value);
|
|
|
|
#if defined RTLD_BOOTSTRAP && !USE___THREAD
|
|
assert (r_type == R_X86_64_GLOB_DAT || r_type == R_X86_64_JUMP_SLOT);
|
|
*reloc_addr = value + reloc->r_addend;
|
|
#else
|
|
switch (r_type)
|
|
{
|
|
case R_X86_64_GLOB_DAT:
|
|
case R_X86_64_JUMP_SLOT:
|
|
*reloc_addr = value + reloc->r_addend;
|
|
break;
|
|
|
|
#if defined USE_TLS && !defined RESOLVE_CONFLICT_FIND_MAP
|
|
case R_X86_64_DTPMOD64:
|
|
# ifdef RTLD_BOOTSTRAP
|
|
/* During startup the dynamic linker is always the module
|
|
with index 1.
|
|
XXX If this relocation is necessary move before RESOLVE
|
|
call. */
|
|
*reloc_addr = 1;
|
|
# else
|
|
/* Get the information from the link map returned by the
|
|
resolve function. */
|
|
if (sym_map != NULL)
|
|
*reloc_addr = sym_map->l_tls_modid;
|
|
# endif
|
|
break;
|
|
case R_X86_64_DTPOFF64:
|
|
# ifndef RTLD_BOOTSTRAP
|
|
/* During relocation all TLS symbols are defined and used.
|
|
Therefore the offset is already correct. */
|
|
if (sym != NULL)
|
|
*reloc_addr = sym->st_value + reloc->r_addend;
|
|
# endif
|
|
break;
|
|
case R_X86_64_TPOFF64:
|
|
/* The offset is negative, forward from the thread pointer. */
|
|
# ifndef RTLD_BOOTSTRAP
|
|
if (sym != NULL)
|
|
# endif
|
|
{
|
|
# ifndef RTLD_BOOTSTRAP
|
|
CHECK_STATIC_TLS (map, sym_map);
|
|
# endif
|
|
/* We know the offset of the object the symbol is contained in.
|
|
It is a negative value which will be added to the
|
|
thread pointer. */
|
|
*reloc_addr = (sym->st_value + reloc->r_addend
|
|
- sym_map->l_tls_offset);
|
|
}
|
|
break;
|
|
#endif /* use TLS */
|
|
|
|
#ifndef RTLD_BOOTSTRAP
|
|
case R_X86_64_64:
|
|
*reloc_addr = value + reloc->r_addend;
|
|
break;
|
|
case R_X86_64_32:
|
|
*(unsigned int *) reloc_addr = value + reloc->r_addend;
|
|
if (value + reloc->r_addend > UINT_MAX)
|
|
{
|
|
const char *strtab;
|
|
|
|
strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
|
|
|
|
_dl_error_printf ("\
|
|
%s: Symbol `%s' causes overflow in R_X86_64_32 relocation\n",
|
|
rtld_progname ?: "<program name unknown>",
|
|
strtab + refsym->st_name);
|
|
}
|
|
break;
|
|
# ifndef RESOLVE_CONFLICT_FIND_MAP
|
|
/* Not needed for dl-conflict.c. */
|
|
case R_X86_64_PC32:
|
|
*(unsigned int *) reloc_addr = value + reloc->r_addend
|
|
- (Elf64_Addr) reloc_addr;
|
|
if (value + reloc->r_addend - (Elf64_Addr) reloc_addr
|
|
!= (int)(value + reloc->r_addend - (Elf64_Addr) reloc_addr))
|
|
{
|
|
const char *strtab;
|
|
|
|
strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
|
|
|
|
_dl_error_printf ("\
|
|
%s: Symbol `%s' causes overflow in R_X86_64_PC32 relocation\n",
|
|
rtld_progname ?: "<program name unknown>",
|
|
strtab + refsym->st_name);
|
|
}
|
|
break;
|
|
case R_X86_64_COPY:
|
|
if (sym == NULL)
|
|
/* This can happen in trace mode if an object could not be
|
|
found. */
|
|
break;
|
|
if (__builtin_expect (sym->st_size > refsym->st_size, 0)
|
|
|| (__builtin_expect (sym->st_size < refsym->st_size, 0)
|
|
&& GLRO(dl_verbose)))
|
|
{
|
|
const char *strtab;
|
|
|
|
strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
|
|
_dl_error_printf ("\
|
|
%s: Symbol `%s' has different size in shared object, consider re-linking\n",
|
|
rtld_progname ?: "<program name unknown>",
|
|
strtab + refsym->st_name);
|
|
}
|
|
memcpy (reloc_addr_arg, (void *) value,
|
|
MIN (sym->st_size, refsym->st_size));
|
|
break;
|
|
# endif
|
|
default:
|
|
_dl_reloc_bad_type (map, r_type, 0);
|
|
break;
|
|
#endif
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
auto inline void
|
|
__attribute ((always_inline))
|
|
elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
|
|
void *const reloc_addr_arg)
|
|
{
|
|
Elf64_Addr *const reloc_addr = reloc_addr_arg;
|
|
assert (ELF64_R_TYPE (reloc->r_info) == R_X86_64_RELATIVE);
|
|
*reloc_addr = l_addr + reloc->r_addend;
|
|
}
|
|
|
|
auto inline void
|
|
__attribute ((always_inline))
|
|
elf_machine_lazy_rel (struct link_map *map,
|
|
Elf64_Addr l_addr, const Elf64_Rela *reloc)
|
|
{
|
|
Elf64_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
|
|
const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
|
|
|
|
/* Check for unexpected PLT reloc type. */
|
|
if (__builtin_expect (r_type == R_X86_64_JUMP_SLOT, 1))
|
|
{
|
|
if (__builtin_expect (map->l_mach.plt, 0) == 0)
|
|
*reloc_addr += l_addr;
|
|
else
|
|
*reloc_addr =
|
|
map->l_mach.plt
|
|
+ (((Elf64_Addr) reloc_addr) - map->l_mach.gotplt) * 2;
|
|
}
|
|
else
|
|
_dl_reloc_bad_type (map, r_type, 1);
|
|
}
|
|
|
|
#endif /* RESOLVE_MAP */
|