/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
/* Copyright (C) 2014 Stony Brook University
This file is part of Graphene Library OS.
Graphene Library OS 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 3 of the
License, or (at your option) any later version.
Graphene Library OS 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 this program. If not, see . */
/*
* dl-machine-x86_64.h
*
* This files contain architecture-specific implementation of ELF dynamic
* relocation function.
* The source code is imported and modified from the GNU C Library.
*/
#ifndef dl_machine_h
#define dl_machine_h
#define ELF_MACHINE_NAME "x86_64"
#include
#include "pal_internal.h"
/* The x86-64 never uses Elf64_Rel relocations. */
#define ELF_MACHINE_NO_REL 1
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
MAP is the object containing the reloc. */
//#define DEBUG_RELOC
static void
elf_machine_rela (struct link_map *l, Elf64_Rela *reloc, Elf64_Sym *sym,
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);
const char * __attribute_unused strtab =
(const void *) D_PTR (l->l_info[DT_STRTAB]);
#ifdef DEBUG_RELOC
#define debug_reloc(r_type) \
do { \
if (strtab && sym && sym->st_name) \
printf("%p " #r_type ": %s %p\n", reloc_addr, \
strtab + sym->st_name, value); \
else if (value) \
printf("%p " #r_type ": %p\n", reloc_addr, value); \
else \
printf("%p " #r_type "\n", reloc_addr, value); \
} while (0)
#else
#define debug_reloc(...) do {} while (0)
#endif
if (__builtin_expect (r_type == R_X86_64_RELATIVE, 0)) {
/* 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. */
//*reloc_addr = l->l_addr + reloc->r_addend;
return;
}
if (__builtin_expect (r_type == R_X86_64_NONE, 0))
return;
Elf64_Addr value = l->l_addr + sym->st_value;
#ifndef RTLD_BOOTSTRAP
struct link_map * sym_map = 0;
if (sym->st_shndx == SHN_UNDEF) {
value = RESOLVE_RTLD(strtab + sym->st_name);
if (!value) {
sym_map = RESOLVE_MAP(&strtab, &sym);
if (!sym_map)
return;
assert(sym);
value = sym_map->l_addr + sym->st_value;
}
#if CACHE_LOADED_BINARIES == 1
if (!sym_map || sym_map->l_type == OBJECT_RTLD) {
assert(l->nrelocs < NRELOCS);
l->relocs[l->nrelocs++] = reloc_addr;
}
#endif
}
#endif
if (__builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC, 0)
&& __builtin_expect (sym->st_shndx != SHN_UNDEF, 1))
value = ((Elf64_Addr (*) (void)) value) ();
/* In the libc loader, they guaranteed that only R_ARCH_RELATIVE,
R_ARCH_GLOB_DAT, R_ARCH_JUMP_SLOT appear in ld.so. We observed
the same thing in libpal.so, so we are gonna to make the same
assumption */
switch (r_type) {
case R_X86_64_GLOB_DAT:
debug_reloc(R_X86_64_GLOB_DAT);
*reloc_addr = value + reloc->r_addend;
break;
case R_X86_64_JUMP_SLOT:
debug_reloc(R_X86_64_JUMP_SLOT);
*reloc_addr = value + reloc->r_addend;
break;
#ifndef RTLD_BOOTSTRAP
case R_X86_64_64:
debug_reloc(R_X86_64_64);
*reloc_addr = value + reloc->r_addend;
break;
case R_X86_64_32:
debug_reloc(R_X86_64_32);
value += reloc->r_addend;
*(Elf64_Addr *) reloc_addr = value;
break;
/* Not needed for dl-conflict.c. */
case R_X86_64_PC32:
debug_reloc(R_X86_64_PC32);
value += reloc->r_addend - (Elf64_Addr) reloc_addr;
*(Elf64_Addr *) reloc_addr = value;
break;
case R_X86_64_IRELATIVE:
debug_reloc(R_X86_64_IRELATIVE);
value = sym_map->l_addr + reloc->r_addend;
value = ((Elf64_Addr (*) (void)) value) ();
*reloc_addr = value;
break;
#endif
default:
return;
}
#ifndef RTLD_BOOTSTRAP
/* We have relocated the symbol, we don't want the
interpreter to relocate it again. */
reloc->r_info ^= ELF64_R_TYPE (reloc->r_info);
#endif
}
static void
elf_machine_rela_relative (struct link_map *l, 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->l_addr + reloc->r_addend;
}
#endif /* !dl_machine_h */