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(localhost [IPv6:::1]) by gnu-tgl-3.localdomain (Postfix) with ESMTP id 42362C0EE1; Fri, 7 Jan 2022 11:06:32 -0800 (PST) To: binutils@sourceware.org Subject: [PATCH 08/10] x86: Add DT_RELR support Date: Fri, 7 Jan 2022 11:06:29 -0800 Message-Id: <20220107190631.309790-9-hjl.tools@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220107190631.309790-1-hjl.tools@gmail.com> References: <20220107190631.309790-1-hjl.tools@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-3028.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_STOCKGEN, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: "H.J. Lu via Libc-alpha" From: "H.J. Lu" Reply-To: "H.J. Lu" Cc: libc-alpha@sourceware.org, Nick Clifton , Alan Modra Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" DT_RELR is implemented with linker relaxation: 1. During linker relaxation, we scan input relocations with the same logic in relocate_section to determine if a relative relocation should be generated and save the relative relocation candidate information for sizing the DT_RELR section later after all symbols addresses can be determined. For these relative relocations which can't be placed in the DT_RELR section, they will be placed in the rela.dyn/rel.dyn section. 2. When DT_RELR is enabled, _bfd_elf_map_sections_to_segments calls a backend function to size the DT_RELR section which will compute the DT_RELR section size and tell ldelf_map_segments to layout sections again when the DT_RELR section size has been increased. 3. After regular symbol processing is finished, bfd_elf_final_link calls a backend function to finish the DT_RELR section. * elf32-i386.c (elf_i386_scan_relocs): Set SEC_ELF_REVERSE_COPY on input section for DT_RELR. (elf_i386_relocate_section): Don't generate relative relocation when DT_RELR is enabled. * elf64-x86-64.c (elf_x86_64_scan_relocs): Set SEC_ELF_REVERSE_COPY on input section for DT_RELR. (elf_x86_64_relocate_section): Don't generate relative relocation when DT_RELR is enabled. * elfxx-x86.c (_bfd_x86_elf_link_hash_table_create): Initialize relative_r_type, relative_r_name, elf_append_reloc, elf_write_addend and elf_write_addend_in_got. (elf_x86_relative_reloc_record_add): New function. (_bfd_x86_elf_link_relax_section): Likewise. (elf64_dt_relr_bitmap_add): Likewise. (elf32_dt_relr_bitmap_add): Likewise. (_bfd_elf32_write_addend): Likewise. (_bfd_elf64_write_addend): Likewise. (elf_x86_size_or_finish_relative_reloc): Likewise. (elf_x86_compute_dl_relr_bitmap): Likewise. (elf_x86_write_dl_relr_bitmap): Likewise. (elf_x86_relative_reloc_compare ): Likewise. (_bfd_elf_x86_size_relative_relocs): Likewise. (_bfd_elf_x86_finish_relative_relocs): Likewise. (_bfd_x86_elf_size_dynamic_sections): Skip the .relr.dyn section. (_bfd_x86_elf_finish_dynamic_sections): Convert 3 spare dynamic tags to DT_RELR, DT_RELRSZ and for compact relative relocation. * elfxx-x86.h (X86_64_GOT_TYPE_P): New. (I386_GOT_TYPE_P): Likewise. (X86_GOT_TYPE_P): Likewise. (X86_64_RELATIVE_RELOC_TYPE_P): Likewise. (I386_RELATIVE_RELOC_TYPE_P): Likewise. (X86_RELATIVE_RELOC_TYPE_P): Likewise. (X86_LOCAL_GOT_RELATIVE_RELOC_P): Likewise. (I386_PCREL_TYPE_P): Likewise. (X86_64_PCREL_TYPE_P): Likewise. (X86_64_NEED_DYNAMIC_RELOC_TYPE_P): Rewrite. (I386_NEED_DYNAMIC_RELOC_TYPE_P): Likewise. (GENERATE_DYNAMIC_RELOCATION_P): Also check rel_from_abs. (elf_x86_link_hash_entry): Add got_relative_reloc_done. (elf_x86_relative_reloc_record): New. (elf_x86_relative_reloc_data): Likewise. (elf_dt_relr_bitmap): Likewise. (elf_x86_link_hash_table): Add dt_relr_bitmap, relative_reloc, unaligned_relative_reloc, relative_r_type, relative_r_name, elf_append_reloc, elf_write_addend, elf_write_addend_in_got and relative_reloc_done. (elf_x86_relative_reloc_done): New. (relative_reloc_packed): Likewise. (_bfd_x86_elf_link_relax_section): Likewise. (_bfd_elf_x86_size_relative_relocs): Likewise. (_bfd_elf_x86_finish_relative_relocs): Likewise. (_bfd_elf32_write_addend): Likewise. (_bfd_elf64_write_addend): Likewise. (bfd_elf32_bfd_relax_section): Likewise. (bfd_elf64_bfd_relax_section): Likewise. (elf_backend_size_relative_relocs): Likewise. (elf_backend_finish_relative_relocs): Likewise. (elf_x86_allocate_local_got_info): Also allocate relative_reloc_done. --- bfd/elf32-i386.c | 54 ++- bfd/elf64-x86-64.c | 63 ++- bfd/elfxx-x86.c | 937 +++++++++++++++++++++++++++++++++++++++++++++ bfd/elfxx-x86.h | 147 ++++++- 4 files changed, 1161 insertions(+), 40 deletions(-) diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index d1f61be5044..8e34bf0bcb4 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -1456,6 +1456,7 @@ elf_i386_scan_relocs (bfd *abfd, asection *sec, const Elf_Internal_Rela *relocs) { + const struct elf_backend_data *bed; struct elf_x86_link_hash_table *htab; Elf_Internal_Shdr *symtab_hdr; struct elf_link_hash_entry **sym_hashes; @@ -1485,6 +1486,14 @@ elf_i386_scan_relocs (bfd *abfd, return false; } + bed = get_elf_backend_data (abfd); + + /* Set SEC_ELF_REVERSE_COPY here so that the correct section offset + will be used for DT_RELR. */ + if (!_bfd_elf_process_reverse_copy (sec, 4, + bed->s->int_rels_per_ext_rel)) + return false; + symtab_hdr = &elf_symtab_hdr (abfd); sym_hashes = elf_sym_hashes (abfd); @@ -2473,8 +2482,10 @@ elf_i386_relocate_section (bfd *output_bfd, bfd_put_32 (output_bfd, relocation, htab->elf.sgot->contents + off); h->got.offset |= 1; - - if (GENERATE_RELATIVE_RELOC_P (info, h)) + /* NB: Don't generate relative relocation here if + it has been generated by DT_RELR. */ + if (!info->enable_dt_relr + && GENERATE_RELATIVE_RELOC_P (info, h)) { /* PR ld/21402: If this symbol isn't dynamic in PIC, generate R_386_RELATIVE here. */ @@ -2504,7 +2515,9 @@ elf_i386_relocate_section (bfd *output_bfd, htab->elf.sgot->contents + off); local_got_offsets[r_symndx] |= 1; - if (bfd_link_pic (info)) + /* NB: Don't generate relative relocation here if it + has been generated by DT_RELR. */ + if (!info->enable_dt_relr && bfd_link_pic (info)) relative_reloc = true; } } @@ -2707,6 +2720,7 @@ elf_i386_relocate_section (bfd *output_bfd, { Elf_Internal_Rela outrel; bool skip, relocate; + bool generate_dynamic_reloc = true; asection *sreloc; /* When generating a shared object, these relocations @@ -2734,23 +2748,33 @@ elf_i386_relocate_section (bfd *output_bfd, { /* This symbol is local, or marked to become local. */ relocate = true; - outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE); + /* NB: Don't generate relative relocation here if it + has been generated by DT_RELR. */ + if (info->enable_dt_relr) + generate_dynamic_reloc = false; + else + { + outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE); - if (htab->params->report_relative_reloc) - _bfd_x86_elf_link_report_relative_reloc - (info, input_section, h, sym, "R_386_RELATIVE", - &outrel); + if (htab->params->report_relative_reloc) + _bfd_x86_elf_link_report_relative_reloc + (info, input_section, h, sym, "R_386_RELATIVE", + &outrel); + } } - sreloc = elf_section_data (input_section)->sreloc; - - if (sreloc == NULL || sreloc->contents == NULL) + if (generate_dynamic_reloc) { - r = bfd_reloc_notsupported; - goto check_relocation_error; - } + sreloc = elf_section_data (input_section)->sreloc; - elf_append_rel (output_bfd, sreloc, &outrel); + if (sreloc == NULL || sreloc->contents == NULL) + { + r = bfd_reloc_notsupported; + goto check_relocation_error; + } + + elf_append_rel (output_bfd, sreloc, &outrel); + } /* If this reloc is against an external symbol, we do not want to fiddle with the addend. Otherwise, we diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index ad885f89e11..0842df33c75 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -1826,6 +1826,7 @@ elf_x86_64_scan_relocs (bfd *abfd, struct bfd_link_info *info, asection *sec, const Elf_Internal_Rela *relocs) { + const struct elf_backend_data *bed; struct elf_x86_link_hash_table *htab; Elf_Internal_Shdr *symtab_hdr; struct elf_link_hash_entry **sym_hashes; @@ -1855,6 +1856,14 @@ elf_x86_64_scan_relocs (bfd *abfd, struct bfd_link_info *info, return false; } + bed = get_elf_backend_data (abfd); + + /* Set SEC_ELF_REVERSE_COPY here so that the correct section offset + will be used for DT_RELR. */ + if (!_bfd_elf_process_reverse_copy (sec, ABI_64_P (abfd) ? 8 : 4, + bed->s->int_rels_per_ext_rel)) + return false; + symtab_hdr = &elf_symtab_hdr (abfd); sym_hashes = elf_sym_hashes (abfd); @@ -2867,7 +2876,10 @@ elf_x86_64_relocate_section (bfd *output_bfd, as -1 | 1 still is -1. */ h->got.offset |= 1; - if (GENERATE_RELATIVE_RELOC_P (info, h)) + /* NB: Don't generate relative relocation here if + it has been generated by DT_RELR. */ + if (!info->enable_dt_relr + && GENERATE_RELATIVE_RELOC_P (info, h)) { /* If this symbol isn't dynamic in PIC, generate R_X86_64_RELATIVE here. */ @@ -2899,8 +2911,11 @@ elf_x86_64_relocate_section (bfd *output_bfd, /* NB: GOTPCREL relocations against local absolute symbol store relocation value in the GOT slot - without relative relocation. */ - if (bfd_link_pic (info) + without relative relocation. Don't generate + relative relocation here if it has been generated + by DT_RELR. */ + if (!info->enable_dt_relr + && bfd_link_pic (info) && !(sym->st_shndx == SHN_ABS && (r_type == R_X86_64_GOTPCREL || r_type == R_X86_64_GOTPCRELX @@ -3215,6 +3230,7 @@ elf_x86_64_relocate_section (bfd *output_bfd, { Elf_Internal_Rela outrel; bool skip, relocate; + bool generate_dynamic_reloc = true; asection *sreloc; const char *relative_reloc_name = NULL; @@ -3253,9 +3269,17 @@ elf_x86_64_relocate_section (bfd *output_bfd, && htab->params->no_reloc_overflow_check)) { relocate = true; - outrel.r_info = htab->r_info (0, R_X86_64_RELATIVE); - outrel.r_addend = relocation + rel->r_addend; - relative_reloc_name = "R_X86_64_RELATIVE"; + /* NB: Don't generate relative relocation here if + it has been generated by DT_RELR. */ + if (info->enable_dt_relr) + generate_dynamic_reloc = false; + else + { + outrel.r_info = + htab->r_info (0, R_X86_64_RELATIVE); + outrel.r_addend = relocation + rel->r_addend; + relative_reloc_name = "R_X86_64_RELATIVE"; + } } else if (r_type == R_X86_64_64 && !ABI_64_P (output_bfd)) @@ -3323,21 +3347,24 @@ elf_x86_64_relocate_section (bfd *output_bfd, } } - sreloc = elf_section_data (input_section)->sreloc; - - if (sreloc == NULL || sreloc->contents == NULL) + if (generate_dynamic_reloc) { - r = bfd_reloc_notsupported; - goto check_relocation_error; - } + sreloc = elf_section_data (input_section)->sreloc; - if (relative_reloc_name - && htab->params->report_relative_reloc) - _bfd_x86_elf_link_report_relative_reloc - (info, input_section, h, sym, relative_reloc_name, - &outrel); + if (sreloc == NULL || sreloc->contents == NULL) + { + r = bfd_reloc_notsupported; + goto check_relocation_error; + } - elf_append_rela (output_bfd, sreloc, &outrel); + if (relative_reloc_name + && htab->params->report_relative_reloc) + _bfd_x86_elf_link_report_relative_reloc + (info, input_section, h, sym, + relative_reloc_name, &outrel); + + elf_append_rela (output_bfd, sreloc, &outrel); + } /* If this reloc is against an external symbol, we do not want to fiddle with the addend. Otherwise, we diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c index 25f7717ea88..0f4e6542ef0 100644 --- a/bfd/elfxx-x86.c +++ b/bfd/elfxx-x86.c @@ -726,6 +726,10 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->got_entry_size = 8; ret->pcrel_plt = true; ret->tls_get_addr = "__tls_get_addr"; + ret->relative_r_type = R_X86_64_RELATIVE; + ret->relative_r_name = "R_X86_64_RELATIVE"; + ret->elf_append_reloc = elf_append_rela; + ret->elf_write_addend_in_got = _bfd_elf64_write_addend; } if (ABI_64_P (abfd)) { @@ -733,6 +737,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->pointer_r_type = R_X86_64_64; ret->dynamic_interpreter = ELF64_DYNAMIC_INTERPRETER; ret->dynamic_interpreter_size = sizeof ELF64_DYNAMIC_INTERPRETER; + ret->elf_write_addend = _bfd_elf64_write_addend; } else { @@ -743,6 +748,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->dynamic_interpreter = ELFX32_DYNAMIC_INTERPRETER; ret->dynamic_interpreter_size = sizeof ELFX32_DYNAMIC_INTERPRETER; + ret->elf_write_addend = _bfd_elf32_write_addend; } else { @@ -751,6 +757,11 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->got_entry_size = 4; ret->pcrel_plt = false; ret->pointer_r_type = R_386_32; + ret->relative_r_type = R_386_RELATIVE; + ret->relative_r_name = "R_386_RELATIVE"; + ret->elf_append_reloc = elf_append_rel; + ret->elf_write_addend = _bfd_elf32_write_addend; + ret->elf_write_addend_in_got = _bfd_elf32_write_addend; ret->dynamic_interpreter = ELF32_DYNAMIC_INTERPRETER; ret->dynamic_interpreter_size = sizeof ELF32_DYNAMIC_INTERPRETER; @@ -977,6 +988,902 @@ _bfd_x86_elf_check_relocs (bfd *abfd, return true; } +/* Add an entry to the relative reloc record. */ + +static bool +elf_x86_relative_reloc_record_add + (struct bfd_link_info *info, + struct elf_x86_relative_reloc_data *relative_reloc, + Elf_Internal_Rela *rel, asection *sec, + asection *sym_sec, struct elf_link_hash_entry *h, + Elf_Internal_Sym *sym, bfd_vma offset) +{ + bfd_size_type newidx; + + if (relative_reloc->data == NULL) + { + relative_reloc->data = bfd_malloc + (sizeof (struct elf_x86_relative_reloc_record)); + relative_reloc->count = 0; + relative_reloc->size = 1; + } + + newidx = relative_reloc->count++; + + if (relative_reloc->count > relative_reloc->size) + { + relative_reloc->size <<= 1; + relative_reloc->data = bfd_realloc + (relative_reloc->data, + (relative_reloc->size + * sizeof (struct elf_x86_relative_reloc_record))); + } + + if (relative_reloc->data == NULL) + { + info->callbacks->einfo + /* xgettext:c-format */ + (_("%F%P: %pB: failed to allocate relative reloc record\n"), + info->output_bfd); + return false; + } + + relative_reloc->data[newidx].rel = *rel; + relative_reloc->data[newidx].sec = sec; + if (h != NULL) + { + /* Set SYM to NULL to indicate a global symbol. */ + relative_reloc->data[newidx].sym = NULL; + relative_reloc->data[newidx].u.h = h; + } + else + { + relative_reloc->data[newidx].sym = sym; + relative_reloc->data[newidx].u.sym_sec = sym_sec; + } + relative_reloc->data[newidx].offset = offset; + relative_reloc->data[newidx].address = 0; + return true; +} + +/* After input sections have been mapped to output sections and + addresses of output sections are set initiallly, scan input + relocations with the same logic in relocate_section to determine + if a relative relocation should be generated. Save the relative + relocation candidate information for sizing the DT_RELR section + later after all symbols addresses can be determined. */ + +bool +_bfd_x86_elf_link_relax_section (bfd *abfd ATTRIBUTE_UNUSED, + asection *input_section, + struct bfd_link_info *info, + bool *again) +{ + Elf_Internal_Shdr *symtab_hdr; + Elf_Internal_Rela *internal_relocs; + Elf_Internal_Rela *irel, *irelend; + Elf_Internal_Sym *isymbuf = NULL; + struct elf_link_hash_entry **sym_hashes; + const struct elf_backend_data *bed; + struct elf_x86_link_hash_table *htab; + bfd_vma *local_got_offsets; + bool is_x86_64; + bool unaligned_section; + + if (bfd_link_relocatable (info)) + return true; + + /* Assume we're not going to change any sizes, and we'll only need + one pass. */ + *again = false; + + bed = get_elf_backend_data (abfd); + htab = elf_x86_hash_table (info, bed->target_id); + if (htab == NULL) + return true; + + /* Nothing to do if there are no relocations or relative relocations + have been packed. */ + if (input_section == htab->elf.srelrdyn + || input_section->relative_reloc_packed + || ((input_section->flags & (SEC_RELOC | SEC_ALLOC)) + != (SEC_RELOC | SEC_ALLOC)) + || (input_section->flags & SEC_DEBUGGING) != 0 + || input_section->reloc_count == 0) + return true; + + /* Skip if the section isn't aligned. */ + unaligned_section = input_section->alignment_power == 0; + + is_x86_64 = bed->target_id == X86_64_ELF_DATA; + + symtab_hdr = &elf_tdata (abfd)->symtab_hdr; + sym_hashes = elf_sym_hashes (abfd); + local_got_offsets = elf_local_got_offsets (abfd); + + /* Load the relocations for this section. */ + internal_relocs = + _bfd_elf_link_read_relocs (abfd, input_section, NULL, + (Elf_Internal_Rela *) NULL, + info->keep_memory); + if (internal_relocs == NULL) + return false; + + irelend = internal_relocs + input_section->reloc_count; + for (irel = internal_relocs; irel < irelend; irel++) + { + unsigned int r_type; + unsigned int r_symndx; + Elf_Internal_Sym *isym; + struct elf_link_hash_entry *h; + struct elf_x86_link_hash_entry *eh; + bfd_vma offset; + bool resolved_to_zero; + bool need_copy_reloc_in_pie; + bool pc32_reloc; + asection *sec; + /* Offset must be a multiple of 2. */ + bool unaligned_offset = (irel->r_offset & 1) != 0; + + /* Get the value of the symbol referred to by the reloc. */ + r_symndx = htab->r_sym (irel->r_info); + + r_type = ELF32_R_TYPE (irel->r_info); + /* Clear the R_X86_64_converted_reloc_bit bit. */ + r_type &= ~R_X86_64_converted_reloc_bit; + + sec = NULL; + h = NULL; + + if (r_symndx < symtab_hdr->sh_info) + { + /* Read this BFD's local symbols. */ + if (isymbuf == NULL) + { + isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents; + if (isymbuf == NULL) + isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr, + symtab_hdr->sh_info, 0, + NULL, NULL, NULL); + if (isymbuf == NULL) + goto error_return; + } + + isym = isymbuf + r_symndx; + switch (isym->st_shndx) + { + case SHN_ABS: + sec = bfd_abs_section_ptr; + break; + case SHN_COMMON: + sec = bfd_com_section_ptr; + break; + case SHN_X86_64_LCOMMON: + if (!is_x86_64) + abort (); + sec = &_bfd_elf_large_com_section; + break; + default: + sec = bfd_section_from_elf_index (abfd, isym->st_shndx); + break; + } + + /* Check relocation against local STT_GNU_IFUNC symbol. */ + if (ELF32_ST_TYPE (isym->st_info) == STT_GNU_IFUNC) + { + h = _bfd_elf_x86_get_local_sym_hash (htab, abfd, irel, + true); + if (h == NULL) + goto error_return; + } + + resolved_to_zero = false; + } + else + { + /* Get H and SEC for GENERATE_DYNAMIC_RELOCATION_P below. */ + h = sym_hashes[r_symndx - symtab_hdr->sh_info]; + while (h->root.type == bfd_link_hash_indirect + || h->root.type == bfd_link_hash_warning) + h = (struct elf_link_hash_entry *) h->root.u.i.link; + + if (h->root.type == bfd_link_hash_defined + || h->root.type == bfd_link_hash_defweak) + sec = h->root.u.def.section; + + isym = NULL; + } + + eh = (struct elf_x86_link_hash_entry *) h; + resolved_to_zero = (eh != NULL + && UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh)); + + if (X86_GOT_TYPE_P (is_x86_64, r_type)) + { + /* Pack GOT relative relocations. There should be only a + single R_*_RELATIVE relocation in GOT. */ + if (eh != NULL) + { + if (eh->got_relative_reloc_done) + continue; + + if (!(h->type != STT_GNU_IFUNC + && RESOLVED_LOCALLY_P (info, h, htab) + && GENERATE_RELATIVE_RELOC_P (info, h))) + continue; + + eh->no_finish_dynamic_symbol = 1; + eh->got_relative_reloc_done = 1; + offset = h->got.offset; + } + else + { + if (elf_x86_relative_reloc_done (abfd)[r_symndx]) + continue; + + if (!X86_LOCAL_GOT_RELATIVE_RELOC_P (is_x86_64, info, + isym)) + continue; + + elf_x86_relative_reloc_done (abfd)[r_symndx] = 1; + offset = local_got_offsets[r_symndx]; + } + + if (!elf_x86_relative_reloc_record_add (info, + &htab->relative_reloc, + irel, htab->elf.sgot, + sec, h, isym, offset)) + goto error_return; + + continue; + } + + if (is_x86_64 + && irel->r_addend == 0 + && !ABI_64_P (info->output_bfd)) + { + /* For x32, if addend is zero, treat R_X86_64_64 like + R_X86_64_32 and R_X86_64_SIZE64 like R_X86_64_SIZE32. */ + if (r_type == R_X86_64_64) + r_type = R_X86_64_32; + else if (r_type == R_X86_64_SIZE64) + r_type = R_X86_64_SIZE32; + } + + if (!X86_RELATIVE_RELOC_TYPE_P (is_x86_64, r_type) + || (h != NULL && h->type == STT_GNU_IFUNC)) + continue; + + /* Pack non-GOT relative relocations. */ + if (is_x86_64) + { + need_copy_reloc_in_pie = + (bfd_link_pie (info) + && h != NULL + && (h->needs_copy + || eh->needs_copy + || (h->root.type == bfd_link_hash_undefined)) + && (X86_PCREL_TYPE_P (true, r_type) + || X86_SIZE_TYPE_P (true, r_type))); + pc32_reloc = false; + } + else + { + need_copy_reloc_in_pie = false; + pc32_reloc = r_type == R_386_PC32; + } + + if (GENERATE_DYNAMIC_RELOCATION_P (is_x86_64, info, eh, r_type, + sec, need_copy_reloc_in_pie, + resolved_to_zero, pc32_reloc)) + { + /* When generating a shared object, these relocations + are copied into the output file to be resolved at run + time. */ + offset = _bfd_elf_section_offset (info->output_bfd, info, + input_section, + irel->r_offset); + if (offset == (bfd_vma) -1 + || offset == (bfd_vma) -2 + || COPY_INPUT_RELOC_P (is_x86_64, info, h, r_type)) + continue; + + /* This symbol is local, or marked to become local. When + relocation overflow check is disabled, we convert + R_X86_64_32 to dynamic R_X86_64_RELATIVE. */ + if (is_x86_64 + && !(r_type == htab->pointer_r_type + || (r_type == R_X86_64_32 + && htab->params->no_reloc_overflow_check))) + continue; + + if (!elf_x86_relative_reloc_record_add + (info, + ((unaligned_section || unaligned_offset) + ? &htab->unaligned_relative_reloc + : &htab->relative_reloc), + irel, input_section, sec, h, isym, offset)) + goto error_return; + } + } + + input_section->relative_reloc_packed = 1; + + return true; + +error_return: + if ((unsigned char *) isymbuf != symtab_hdr->contents) + free (isymbuf); + if (elf_section_data (input_section)->relocs != internal_relocs) + free (internal_relocs); + return false; +} + +/* Add an entry to the 64-bit DT_RELR bitmap. */ + +static void +elf64_dt_relr_bitmap_add + (struct bfd_link_info *info, struct elf_dt_relr_bitmap *bitmap, + uint64_t entry) +{ + bfd_size_type newidx; + + if (bitmap->u.elf64 == NULL) + { + bitmap->u.elf64 = bfd_malloc (sizeof (uint64_t)); + bitmap->count = 0; + bitmap->size = 1; + } + + newidx = bitmap->count++; + + if (bitmap->count > bitmap->size) + { + bitmap->size <<= 1; + bitmap->u.elf64 = bfd_realloc (bitmap->u.elf64, + (bitmap->size * sizeof (uint64_t))); + } + + if (bitmap->u.elf64 == NULL) + { + info->callbacks->einfo + /* xgettext:c-format */ + (_("%F%P: %pB: failed to allocate 64-bit DT_RELR bitmap\n"), + info->output_bfd); + } + + bitmap->u.elf64[newidx] = entry; +} + +/* Add an entry to the 32-bit DT_RELR bitmap. */ + +static void +elf32_dt_relr_bitmap_add + (struct bfd_link_info *info, struct elf_dt_relr_bitmap *bitmap, + uint32_t entry) +{ + bfd_size_type newidx; + + if (bitmap->u.elf32 == NULL) + { + bitmap->u.elf32 = bfd_malloc (sizeof (uint32_t)); + bitmap->count = 0; + bitmap->size = 1; + } + + newidx = bitmap->count++; + + if (bitmap->count > bitmap->size) + { + bitmap->size <<= 1; + bitmap->u.elf32 = bfd_realloc (bitmap->u.elf32, + (bitmap->size * sizeof (uint32_t))); + } + + if (bitmap->u.elf32 == NULL) + { + info->callbacks->einfo + /* xgettext:c-format */ + (_("%F%P: %pB: failed to allocate 32-bit DT_RELR bitmap\n"), + info->output_bfd); + } + + bitmap->u.elf32[newidx] = entry; +} + +void +_bfd_elf32_write_addend (bfd *abfd, uint64_t value, void *addr) +{ + bfd_put_32 (abfd, value, addr); +} + +void +_bfd_elf64_write_addend (bfd *abfd, uint64_t value, void *addr) +{ + bfd_put_64 (abfd, value, addr); +} + +/* Size or finish relative relocations to determine the run-time + addresses for DT_RELR bitmap computation later. OUTREL is set + to NULL in the sizing phase and non-NULL in the finising phase + where the regular relative relocations will be written out. */ + +static void +elf_x86_size_or_finish_relative_reloc + (bool is_x86_64, struct bfd_link_info *info, + struct elf_x86_link_hash_table *htab, bool unaligned, + Elf_Internal_Rela *outrel) +{ + unsigned int align_mask; + bfd_size_type i, count; + asection *sec, *srel; + struct elf_link_hash_entry *h; + bfd_vma offset; + Elf_Internal_Sym *sym; + asection *sym_sec; + asection *sgot = htab->elf.sgot; + asection *srelgot = htab->elf.srelgot; + struct elf_x86_relative_reloc_data *relative_reloc; + + if (unaligned) + { + align_mask = 0; + relative_reloc = &htab->unaligned_relative_reloc; + } + else + { + align_mask = 1; + relative_reloc = &htab->relative_reloc; + } + + count = relative_reloc->count; + for (i = 0; i < count; i++) + { + sec = relative_reloc->data[i].sec; + sym = relative_reloc->data[i].sym; + + /* If SYM is NULL, it must be a global symbol. */ + if (sym == NULL) + h = relative_reloc->data[i].u.h; + else + h = NULL; + + if (is_x86_64) + { + bfd_vma relocation; + /* This function may be called more than once and REL may be + updated by _bfd_elf_rela_local_sym below. */ + Elf_Internal_Rela rel = relative_reloc->data[i].rel; + + if (h != NULL) + { + if (h->root.type == bfd_link_hash_defined + || h->root.type == bfd_link_hash_defweak) + { + sym_sec = h->root.u.def.section; + relocation = (h->root.u.def.value + + sym_sec->output_section->vma + + sym_sec->output_offset); + } + else + { + /* Allow undefined symbol only at the sizing phase. */ + if (outrel == NULL) + relocation = 0; + else + abort (); + } + } + else + { + sym_sec = relative_reloc->data[i].u.sym_sec; + relocation = _bfd_elf_rela_local_sym + (info->output_bfd, sym, &sym_sec, &rel); + } + + if (outrel != NULL) + { + outrel->r_addend = relocation; + if (sec == sgot) + { + if (h != NULL && h->needs_plt) + abort (); + } + else + outrel->r_addend += rel.r_addend; + + /* Write the implicit addend if ALIGN_MASK isn't 0. */ + if (align_mask) + { + if (sec == sgot) + { + if (relative_reloc->data[i].offset >= sec->size) + abort (); + htab->elf_write_addend_in_got + (info->output_bfd, outrel->r_addend, + sec->contents + relative_reloc->data[i].offset); + } + else + { + if (rel.r_offset >= sec->size) + abort (); + htab->elf_write_addend + (info->output_bfd, outrel->r_addend, + (elf_section_data (sec)->this_hdr.contents + + rel.r_offset)); + } + } + } + } + + if (sec == sgot) + srel = srelgot; + else + srel = elf_section_data (sec)->sreloc; + offset = (sec->output_section->vma + sec->output_offset + + relative_reloc->data[i].offset); + relative_reloc->data[i].address = offset; + if (outrel != NULL) + { + outrel->r_offset = offset; + + if ((outrel->r_offset & align_mask) != 0) + abort (); + + if (htab->params->report_relative_reloc) + _bfd_x86_elf_link_report_relative_reloc + (info, sec, h, sym, htab->relative_r_name, outrel); + + /* Generate regular relative relocation if ALIGN_MASK is 0. */ + if (align_mask == 0) + htab->elf_append_reloc (info->output_bfd, srel, outrel); + } + } +} + +/* Compute the DT_RELR section size. Set NEED_PLAYOUT to true if + the DT_RELR section size has been increased. */ + +static void +elf_x86_compute_dl_relr_bitmap + (struct bfd_link_info *info, struct elf_x86_link_hash_table *htab, + bool *need_layout) +{ + bfd_vma base; + bfd_size_type i, count, new_count; + struct elf_x86_relative_reloc_data *relative_reloc = + &htab->relative_reloc; + /* Save the old DT_RELR bitmap count. Don't shrink the DT_RELR bitmap + if the new DT_RELR bitmap count is smaller than the old one. Pad + with trailing 1s which won't be decoded to more relocations. */ + bfd_size_type dt_relr_bitmap_count = htab->dt_relr_bitmap.count; + + /* Clear the DT_RELR bitmap count. */ + htab->dt_relr_bitmap.count = 0; + + count = relative_reloc->count; + + if (ABI_64_P (info->output_bfd)) + { + /* Compute the 64-bit DT_RELR bitmap. */ + i = 0; + while (i < count) + { + if ((relative_reloc->data[i].address % 1) != 0) + abort (); + + elf64_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap, + relative_reloc->data[i].address); + + base = relative_reloc->data[i].address + 8; + i++; + + while (i < count) + { + uint64_t bitmap = 0; + for (; i < count; i++) + { + bfd_vma delta = (relative_reloc->data[i].address + - base); + /* Stop if it is too far from base. */ + if (delta >= 63 * 8) + break; + /* Stop if it isn't a multiple of 8. */ + if ((delta % 8) != 0) + break; + bitmap |= 1ULL << (delta / 8); + } + + if (bitmap == 0) + break; + + elf64_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap, + (bitmap << 1) | 1); + + base += 63 * 8; + } + } + + new_count = htab->dt_relr_bitmap.count; + if (dt_relr_bitmap_count > new_count) + { + /* Don't shrink the DT_RELR section size to avoid section + layout oscillation. Instead, pad the DT_RELR bitmap with + 1s which do not decode to more relocations. */ + + htab->dt_relr_bitmap.count = dt_relr_bitmap_count; + count = dt_relr_bitmap_count - new_count; + for (i = 0; i < count; i++) + htab->dt_relr_bitmap.u.elf64[new_count + i] = 1; + } + } + else + { + /* Compute the 32-bit DT_RELR bitmap. */ + i = 0; + while (i < count) + { + if ((relative_reloc->data[i].address % 1) != 0) + abort (); + + elf32_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap, + relative_reloc->data[i].address); + + base = relative_reloc->data[i].address + 4; + i++; + + while (i < count) + { + uint32_t bitmap = 0; + for (; i < count; i++) + { + bfd_vma delta = (relative_reloc->data[i].address + - base); + /* Stop if it is too far from base. */ + if (delta >= 31 * 4) + break; + /* Stop if it isn't a multiple of 4. */ + if ((delta % 4) != 0) + break; + bitmap |= 1ULL << (delta / 4); + } + + if (bitmap == 0) + break; + + elf32_dt_relr_bitmap_add (info, &htab->dt_relr_bitmap, + (bitmap << 1) | 1); + + base += 31 * 4; + } + } + + new_count = htab->dt_relr_bitmap.count; + if (dt_relr_bitmap_count > new_count) + { + /* Don't shrink the DT_RELR section size to avoid section + layout oscillation. Instead, pad the DT_RELR bitmap with + 1s which do not decode to more relocations. */ + + htab->dt_relr_bitmap.count = dt_relr_bitmap_count; + count = dt_relr_bitmap_count - new_count; + for (i = 0; i < count; i++) + htab->dt_relr_bitmap.u.elf32[new_count + i] = 1; + } + } + + if (htab->dt_relr_bitmap.count != dt_relr_bitmap_count) + { + if (need_layout) + { + /* The .relr.dyn section size is changed. Update the section + size and tell linker to layout sections again. */ + htab->elf.srelrdyn->size = + (htab->dt_relr_bitmap.count + * (ABI_64_P (info->output_bfd) ? 8 : 4)); + + *need_layout = true; + } + else + info->callbacks->einfo + /* xgettext:c-format */ + (_("%F%P: %pB: size of compact relative reloc section is " + "changed: new (%lu) != old (%lu)\n"), + info->output_bfd, htab->dt_relr_bitmap.count, + dt_relr_bitmap_count); + } +} + +/* Write out the DT_RELR section. */ + +static void +elf_x86_write_dl_relr_bitmap (struct bfd_link_info *info, + struct elf_x86_link_hash_table *htab) +{ + asection *sec = htab->elf.srelrdyn; + bfd_size_type size = sec->size; + bfd_size_type i; + unsigned char *contents; + + contents = (unsigned char *) bfd_alloc (sec->owner, size); + if (contents == NULL) + info->callbacks->einfo + /* xgettext:c-format */ + (_("%F%P: %pB: failed to allocate compact relative reloc section\n"), + info->output_bfd); + + /* Cache the section contents for elf_link_input_bfd. */ + sec->contents = contents; + + if (ABI_64_P (info->output_bfd)) + for (i = 0; i < htab->dt_relr_bitmap.count; i++, contents += 8) + bfd_put_64 (info->output_bfd, htab->dt_relr_bitmap.u.elf64[i], + contents); + else + for (i = 0; i < htab->dt_relr_bitmap.count; i++, contents += 4) + bfd_put_32 (info->output_bfd, htab->dt_relr_bitmap.u.elf32[i], + contents); +} + +/* Sort relative relocations by address. */ + +static int +elf_x86_relative_reloc_compare (const void *pa, const void *pb) +{ + struct elf_x86_relative_reloc_record *a = + (struct elf_x86_relative_reloc_record *) pa; + struct elf_x86_relative_reloc_record *b = + (struct elf_x86_relative_reloc_record *) pb; + if (a->address < b->address) + return -1; + if (a->address > b->address) + return 1; + return 0; +} + +bool +_bfd_elf_x86_size_relative_relocs (struct bfd_link_info *info, + bool *need_layout) +{ + struct elf_x86_link_hash_table *htab; + const struct elf_backend_data *bed; + bool is_x86_64; + bfd_size_type i, count, unaligned_count; + asection *sec, *srel; + + /* Do nothing for ld -r. */ + if (bfd_link_relocatable (info)) + return true; + + bed = get_elf_backend_data (info->output_bfd); + htab = elf_x86_hash_table (info, bed->target_id); + if (htab == NULL) + return false; + + count = htab->relative_reloc.count; + unaligned_count = htab->unaligned_relative_reloc.count; + if (count == 0) + { + if (htab->generate_relative_reloc_pass == 0 + && htab->elf.srelrdyn != NULL) + { + /* Remove the empty .relr.dyn sections now. */ + if (!bfd_is_abs_section (htab->elf.srelrdyn->output_section)) + { + bfd_section_list_remove + (info->output_bfd, htab->elf.srelrdyn->output_section); + info->output_bfd->section_count--; + } + bfd_section_list_remove (htab->elf.srelrdyn->owner, + htab->elf.srelrdyn); + htab->elf.srelrdyn->owner->section_count--; + } + if (unaligned_count == 0) + { + htab->generate_relative_reloc_pass++; + return true; + } + } + + is_x86_64 = bed->target_id == X86_64_ELF_DATA; + + /* Size relative relocations. */ + if (htab->generate_relative_reloc_pass) + { + /* Reset the regular relative relocation count. */ + for (i = 0; i < unaligned_count; i++) + { + sec = htab->unaligned_relative_reloc.data[i].sec; + srel = elf_section_data (sec)->sreloc; + srel->reloc_count = 0; + } + } + else + { + /* Remove the reserved space for compact relative relocations. */ + if (count) + { + asection *sgot = htab->elf.sgot; + asection *srelgot = htab->elf.srelgot; + + for (i = 0; i < count; i++) + { + sec = htab->relative_reloc.data[i].sec; + if (sec == sgot) + srel = srelgot; + else + srel = elf_section_data (sec)->sreloc; + srel->size -= htab->sizeof_reloc; + } + } + } + + /* Size unaligned relative relocations. */ + if (unaligned_count) + elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab, + true, NULL); + + if (count) + { + elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab, + false, NULL); + + /* Sort relative relocations by addresses. We only need to + sort them in the first pass since the relative positions + won't change. */ + if (htab->generate_relative_reloc_pass == 0) + qsort (htab->relative_reloc.data, count, + sizeof (struct elf_x86_relative_reloc_record), + elf_x86_relative_reloc_compare); + + elf_x86_compute_dl_relr_bitmap (info, htab, need_layout); + } + + htab->generate_relative_reloc_pass++; + + return true; +} + +bool +_bfd_elf_x86_finish_relative_relocs (struct bfd_link_info *info) +{ + struct elf_x86_link_hash_table *htab; + const struct elf_backend_data *bed; + Elf_Internal_Rela outrel; + bool is_x86_64; + bfd_size_type count; + + /* Do nothing for ld -r. */ + if (bfd_link_relocatable (info)) + return true; + + bed = get_elf_backend_data (info->output_bfd); + htab = elf_x86_hash_table (info, bed->target_id); + if (htab == NULL) + return false; + + is_x86_64 = bed->target_id == X86_64_ELF_DATA; + + outrel.r_info = htab->r_info (0, htab->relative_r_type); + + if (htab->unaligned_relative_reloc.count) + elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab, + true, &outrel); + + count = htab->relative_reloc.count; + if (count) + { + elf_x86_size_or_finish_relative_reloc (is_x86_64, info, htab, + false, &outrel); + + elf_x86_compute_dl_relr_bitmap (info, htab, NULL); + + elf_x86_write_dl_relr_bitmap (info, htab); + } + + return true; +} + bool _bfd_elf_x86_valid_reloc_p (asection *input_section, struct bfd_link_info *info, @@ -1332,6 +2239,11 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, if ((s->flags & SEC_LINKER_CREATED) == 0) continue; + /* The .relr.dyn section for compact relative relocation will + be filled later. */ + if (s == htab->elf.srelrdyn) + continue; + if (s == htab->elf.splt || s == htab->elf.sgot) { @@ -1459,6 +2371,7 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd, asection *sdyn; bfd_byte *dyncon, *dynconend; bfd_size_type sizeof_dyn; + bfd_size_type dt_relr_bitmap_count; bed = get_elf_backend_data (output_bfd); htab = elf_x86_hash_table (info, bed->target_id); @@ -1517,6 +2430,8 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd, if (sdyn == NULL || htab->elf.sgot == NULL) abort (); + dt_relr_bitmap_count = htab->dt_relr_bitmap.count; + sizeof_dyn = bed->s->sizeof_dyn; dyncon = sdyn->contents; dynconend = sdyn->contents + sdyn->size; @@ -1535,6 +2450,28 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd, break; continue; + case DT_NULL: + if (dt_relr_bitmap_count != 0) + { + /* Convert 3 spare dynamic tags to DT_RELR, DT_RELRSZ and + DT_RELRENT for compact relative relocation. */ + s = htab->elf.srelrdyn; + dyn.d_tag = DT_RELR; + dyn.d_un.d_ptr = s->output_section->vma + s->output_offset; + (*bed->s->swap_dyn_out) (output_bfd, &dyn, dyncon); + dyncon += sizeof_dyn; + dyn.d_tag = DT_RELRSZ; + dyn.d_un.d_val = s->size; + (*bed->s->swap_dyn_out) (output_bfd, &dyn, dyncon); + dyncon += sizeof_dyn; + dyn.d_tag = DT_RELRENT; + dyn.d_un.d_val = ABI_64_P (output_bfd) ? 8 : 4; + elf_section_data (s->output_section)->this_hdr.sh_entsize + = dyn.d_un.d_val; + dt_relr_bitmap_count = 0; + } + break; + case DT_PLTGOT: s = htab->elf.sgotplt; dyn.d_un.d_ptr = s->output_section->vma + s->output_offset; diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h index 1bb80280918..4b5784ca08a 100644 --- a/bfd/elfxx-x86.h +++ b/bfd/elfxx-x86.h @@ -47,18 +47,35 @@ #define X86_SIZE_TYPE_P(IS_X86_64, TYPE) \ ((IS_X86_64) ? X86_64_SIZE_TYPE_P(TYPE) : I386_SIZE_TYPE_P (TYPE)) -#define X86_64_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \ - (X86_64_SIZE_TYPE_P (TYPE) \ - || X86_64_PCREL_TYPE_P (TYPE) \ +#define X86_64_GOT_TYPE_P(TYPE) \ + ((TYPE) == R_X86_64_GOTPCREL \ + || (TYPE) == R_X86_64_GOTPCRELX \ + || (TYPE) == R_X86_64_REX_GOTPCRELX) +#define I386_GOT_TYPE_P(TYPE) \ + ((TYPE) == R_386_GOT32 || (TYPE) == R_386_GOT32X) +#define X86_GOT_TYPE_P(IS_X86_64, TYPE) \ + ((IS_X86_64) ? X86_64_GOT_TYPE_P (TYPE) : I386_GOT_TYPE_P (TYPE)) + +#define X86_64_RELATIVE_RELOC_TYPE_P(TYPE) \ + (X86_64_PCREL_TYPE_P (TYPE) \ || (TYPE) == R_X86_64_8 \ || (TYPE) == R_X86_64_16 \ || (TYPE) == R_X86_64_32 \ || (TYPE) == R_X86_64_32S \ || (TYPE) == R_X86_64_64) +#define I386_RELATIVE_RELOC_TYPE_P(TYPE) \ + ((TYPE) == R_386_32 || (TYPE) == R_386_PC32) +#define X86_RELATIVE_RELOC_TYPE_P(IS_X86_64, TYPE) \ + ((IS_X86_64) \ + ? X86_64_RELATIVE_RELOC_TYPE_P (TYPE) \ + : I386_RELATIVE_RELOC_TYPE_P(TYPE)) + +#define X86_64_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \ + (X86_64_SIZE_TYPE_P (TYPE) \ + || X86_64_RELATIVE_RELOC_TYPE_P (TYPE)) #define I386_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \ (I386_SIZE_TYPE_P (TYPE) \ - || I386_PCREL_TYPE_P (TYPE) \ - || (TYPE) == R_386_32 \ + || I386_RELATIVE_RELOC_TYPE_P (TYPE) \ || (TYPE) == R_386_TLS_LE \ || (TYPE) == R_386_TLS_LE_32) #define X86_NEED_DYNAMIC_RELOC_TYPE_P(IS_X86_64, TYPE) \ @@ -66,11 +83,23 @@ ? X86_64_NEED_DYNAMIC_RELOC_TYPE_P (TYPE) \ : I386_NEED_DYNAMIC_RELOC_TYPE_P (TYPE)) +#define X86_LOCAL_GOT_RELATIVE_RELOC_P(IS_X86_64, INFO, SYM) \ + (bfd_link_pic (INFO) \ + && (!(IS_X86_64) || ((SYM) != NULL && (SYM)->st_shndx != SHN_ABS))) + #define PLT_CIE_LENGTH 20 #define PLT_FDE_LENGTH 36 #define PLT_FDE_START_OFFSET 4 + PLT_CIE_LENGTH + 8 #define PLT_FDE_LEN_OFFSET 4 + PLT_CIE_LENGTH + 12 +#define I386_PCREL_TYPE_P(TYPE) ((TYPE) == R_386_PC32) +#define X86_64_PCREL_TYPE_P(TYPE) \ + ((TYPE) == R_X86_64_PC8 \ + || (TYPE) == R_X86_64_PC16 \ + || (TYPE) == R_X86_64_PC32 \ + || (TYPE) == R_X86_64_PC32_BND \ + || (TYPE) == R_X86_64_PC64) + #define ABI_64_P(abfd) \ (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS64) @@ -160,12 +189,18 @@ relocations against resolved undefined weak symbols in PIE, except when PC32_RELOC is TRUE. Undefined weak symbol is bound locally when PIC is false. Don't generate dynamic relocations against - non-preemptible absolute symbol. */ + non-preemptible absolute symbol. NB: rel_from_abs is set on symbols + defined by linker scripts from "dot" (also SEGMENT_START or ORIGIN) + outside of an output section statement, which will be converted from + absolute to section-relative in set_sym_sections called from + ldexp_finalize_syms after ldemul_finish. */ #define GENERATE_DYNAMIC_RELOCATION_P(IS_X86_64, INFO, EH, R_TYPE, \ SEC, NEED_COPY_RELOC_IN_PIE, \ RESOLVED_TO_ZERO, PC32_RELOC) \ ((bfd_link_pic (INFO) \ && !(bfd_is_abs_section (SEC) \ + && ((EH) == NULL \ + || (EH)->elf.root.rel_from_abs == 0) \ && ((EH) == NULL \ || SYMBOL_REFERENCES_LOCAL (INFO, &(EH)->elf))) \ && !(NEED_COPY_RELOC_IN_PIE) \ @@ -302,6 +337,10 @@ struct elf_x86_link_hash_entry /* Don't call finish_dynamic_symbol on this symbol. */ unsigned int no_finish_dynamic_symbol : 1; + /* R_*_RELATIVE relocation in GOT for this symbol has been + processed. */ + unsigned int got_relative_reloc_done : 1; + /* TRUE if symbol is __tls_get_addr. */ unsigned int tls_get_addr : 1; @@ -481,6 +520,52 @@ struct elf_x86_plt_layout #define elf_x86_hash_entry(ent) \ ((struct elf_x86_link_hash_entry *)(ent)) +/* Information of an input relocation used to compute its contribution + to the DT_RELR section size. */ + +struct elf_x86_relative_reloc_record +{ + /* The original relocation info. */ + Elf_Internal_Rela rel; + /* The input or the GOT section where the relocation is applied. */ + asection *sec; + /* Local symbol info. NULL for global symbol. */ + Elf_Internal_Sym *sym; + union + { + /* Section where the local symbol is defined. */ + asection *sym_sec; + /* Global symbol hash. */ + struct elf_link_hash_entry *h; + } u; + /* The offset into the output section where the relative relocation + will be applied at run-time. */ + bfd_vma offset; + /* The run-time address. */ + bfd_vma address; +}; + +struct elf_x86_relative_reloc_data +{ + bfd_size_type count; + bfd_size_type size; + struct elf_x86_relative_reloc_record *data; +}; + +/* DT_RELR bitmap. */ +struct elf_dt_relr_bitmap +{ + bfd_size_type count; + bfd_size_type size; + union + { + /* 32-bit bitmap. */ + uint32_t *elf32; + /* 64-bit bitmap. */ + uint64_t *elf64; + } u; +}; + /* x86 ELF linker hash table. */ struct elf_x86_link_hash_table @@ -533,6 +618,18 @@ struct elf_x86_link_hash_table is only used for i386. */ bfd_vma next_tls_desc_index; + /* DT_RELR bitmap. */ + struct elf_dt_relr_bitmap dt_relr_bitmap; + + /* Relative relocation data. */ + struct elf_x86_relative_reloc_data relative_reloc; + + /* Unaligned relative relocation data. */ + struct elf_x86_relative_reloc_data unaligned_relative_reloc; + + /* Number of relative reloc generation pass. */ + unsigned int generate_relative_reloc_pass; + /* Value used to fill the unused bytes of the first PLT entry. This is only used for i386. */ bfd_byte plt0_pad_byte; @@ -554,9 +651,14 @@ struct elf_x86_link_hash_table unsigned int sizeof_reloc; unsigned int got_entry_size; unsigned int pointer_r_type; + unsigned int relative_r_type; int dynamic_interpreter_size; const char *dynamic_interpreter; const char *tls_get_addr; + const char *relative_r_name; + void (*elf_append_reloc) (bfd *, asection *, Elf_Internal_Rela *); + void (*elf_write_addend) (bfd *, uint64_t, void *); + void (*elf_write_addend_in_got) (bfd *, uint64_t, void *); /* Options passed from the linker. */ struct elf_linker_x86_params *params; @@ -591,6 +693,10 @@ struct elf_x86_obj_tdata /* GOTPLT entries for TLS descriptors. */ bfd_vma *local_tlsdesc_gotent; + + /* R_*_RELATIVE relocation in GOT for this local symbol has been + processed. */ + char *relative_reloc_done; }; enum elf_x86_plt_type @@ -626,6 +732,9 @@ struct elf_x86_plt #define elf_x86_local_tlsdesc_gotent(abfd) \ (elf_x86_tdata (abfd)->local_tlsdesc_gotent) +#define elf_x86_relative_reloc_done(abfd) \ + (elf_x86_tdata (abfd)->relative_reloc_done) + #define elf_x86_compute_jump_table_size(htab) \ ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size) @@ -637,6 +746,7 @@ struct elf_x86_plt /* Rename some of the generic section flags to better document how they are used here. */ #define check_relocs_failed sec_flg0 +#define relative_reloc_packed sec_flg1 extern bool _bfd_x86_elf_mkobject (bfd *); @@ -676,6 +786,18 @@ extern bool _bfd_x86_elf_check_relocs (bfd *, struct bfd_link_info *, asection *, const Elf_Internal_Rela *); +extern bool _bfd_x86_elf_link_relax_section + (bfd *, asection *, struct bfd_link_info *, bool *); + +extern bool _bfd_elf_x86_size_relative_relocs + (struct bfd_link_info *, bool *); + +extern bool _bfd_elf_x86_finish_relative_relocs + (struct bfd_link_info *); + +extern void _bfd_elf32_write_addend (bfd *, uint64_t, void *); +extern void _bfd_elf64_write_addend (bfd *, uint64_t, void *); + extern bool _bfd_elf_x86_valid_reloc_p (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *, const Elf_Internal_Rela *, struct elf_link_hash_entry *, @@ -752,6 +874,10 @@ extern void _bfd_x86_elf_link_report_relative_reloc _bfd_x86_elf_link_check_relocs #define bfd_elf32_bfd_link_check_relocs \ _bfd_x86_elf_link_check_relocs +#define bfd_elf32_bfd_relax_section \ + _bfd_x86_elf_link_relax_section +#define bfd_elf64_bfd_relax_section \ + _bfd_x86_elf_link_relax_section #define elf_backend_check_relocs \ _bfd_x86_elf_check_relocs @@ -777,6 +903,10 @@ extern void _bfd_x86_elf_link_report_relative_reloc _bfd_x86_elf_merge_gnu_properties #define elf_backend_fixup_gnu_properties \ _bfd_x86_elf_link_fixup_gnu_properties +#define elf_backend_size_relative_relocs \ + _bfd_elf_x86_size_relative_relocs +#define elf_backend_finish_relative_relocs \ + _bfd_elf_x86_finish_relative_relocs #define ELF_P_ALIGN ELF_MINPAGESIZE @@ -789,7 +919,8 @@ elf_x86_allocate_local_got_info (bfd *abfd, bfd_size_type count) if (local_got_refcounts == NULL) { bfd_size_type size = count * (sizeof (bfd_signed_vma) - + sizeof (bfd_vma) + sizeof(char)); + + sizeof (bfd_vma) + + 2 * sizeof(char)); local_got_refcounts = (bfd_signed_vma *) bfd_zalloc (abfd, size); if (local_got_refcounts == NULL) return false; @@ -798,6 +929,8 @@ elf_x86_allocate_local_got_info (bfd *abfd, bfd_size_type count) (bfd_vma *) (local_got_refcounts + count); elf_x86_local_got_tls_type (abfd) = (char *) (local_got_refcounts + 2 * count); + elf_x86_relative_reloc_done (abfd) = + ((char *) (local_got_refcounts + 2 * count)) + count; } return true; }