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- /* 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 <http://www.gnu.org/licenses/>. */
- /*
- * 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 <sysdeps/generic/ldsodefs.h>
- #include "pal_internal.h"
- #include "pal_rtld.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 (r_type == R_X86_64_RELATIVE) {
- /* 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 (r_type == R_X86_64_NONE)
- 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 (ELFW(ST_TYPE)(sym->st_info) == STT_GNU_IFUNC && sym->st_shndx != SHN_UNDEF)
- 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 */
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