diff options
| -rw-r--r-- | bfd/ChangeLog | 9 | ||||
| -rw-r--r-- | bfd/elf32-arm.c | 152 |
2 files changed, 152 insertions, 9 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog index f8525a2..11c4297 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,6 +1,15 @@ 2018-04-25 Christophe Lyon <christophe.lyon@st.com> Mickaël Guêné <mickael.guene@st.com> + * elf32-arm.c (elf32_arm_fdpic_plt_entry): New. + (elf32_arm_create_dynamic_sections): Handle FDPIC. + (elf32_arm_allocate_plt_entry): Likewise. + (elf32_arm_populate_plt_entry): Likewise. + (elf32_arm_output_plt_map_1): Likewise. + +2018-04-25 Christophe Lyon <christophe.lyon@st.com> + Mickaël Guêné <mickael.guene@st.com> + * elf32-arm.c (struct fdpic_local): New. (elf_arm_obj_tdata): Add local_fdpic_cnts field. (elf32_arm_local_fdpic_cnts): New. diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index eef143e..9eb12e2 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -2229,6 +2229,22 @@ static const unsigned long dl_tlsdesc_lazy_trampoline [] = 0x00000018, /* 4: .word _GLOBAL_OFFSET_TABLE_ - 2b - 8 */ }; +/* ARM FDPIC PLT entry. */ +/* The last 5 words contain PLT lazy fragment code and data. */ +static const bfd_vma elf32_arm_fdpic_plt_entry [] = + { + 0xe59fc008, /* ldr r12, .L1 */ + 0xe08cc009, /* add r12, r12, r9 */ + 0xe59c9004, /* ldr r9, [r12, #4] */ + 0xe59cf000, /* ldr pc, [r12] */ + 0x00000000, /* L1. .word foo(GOTOFFFUNCDESC) */ + 0x00000000, /* L1. .word foo(funcdesc_value_reloc_offset) */ + 0xe51fc00c, /* ldr r12, [pc, #-12] */ + 0xe92d1000, /* push {r12} */ + 0xe599c004, /* ldr r12, [r9, #4] */ + 0xe599f000, /* ldr pc, [r9] */ + }; + #ifdef FOUR_WORD_PLT /* The first entry in a procedure linkage table looks like @@ -3856,6 +3872,14 @@ elf32_arm_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info) htab->obfd = saved_obfd; } + if (htab->fdpic_p) { + htab->plt_header_size = 0; + if (info->flags & DF_BIND_NOW) + htab->plt_entry_size = 4 * (ARRAY_SIZE(elf32_arm_fdpic_plt_entry) - 5); + else + htab->plt_entry_size = 4 * ARRAY_SIZE(elf32_arm_fdpic_plt_entry); + } + if (!htab->root.splt || !htab->root.srelplt || !htab->root.sdynbss @@ -9392,8 +9416,22 @@ elf32_arm_allocate_plt_entry (struct bfd_link_info *info, splt = htab->root.splt; sgotplt = htab->root.sgotplt; - /* Allocate room for an R_JUMP_SLOT relocation in .rel.plt. */ - elf32_arm_allocate_dynrelocs (info, htab->root.srelplt, 1); + if (htab->fdpic_p) + { + /* Allocate room for R_ARM_FUNCDESC_VALUE. */ + /* For lazy binding, relocations will be put into .rel.plt, in + .rel.got otherwise. */ + /* FIXME: today we don't support lazy binding so put it in .rel.got */ + if (info->flags & DF_BIND_NOW) + elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1); + else + elf32_arm_allocate_dynrelocs (info, htab->root.srelplt, 1); + } + else + { + /* Allocate room for an R_JUMP_SLOT relocation in .rel.plt. */ + elf32_arm_allocate_dynrelocs (info, htab->root.srelplt, 1); + } /* If this is the first .plt entry, make room for the special first entry. */ @@ -9417,7 +9455,11 @@ elf32_arm_allocate_plt_entry (struct bfd_link_info *info, arm_plt->got_offset = sgotplt->size; else arm_plt->got_offset = sgotplt->size - 8 * htab->num_tls_desc; - sgotplt->size += 4; + if (htab->fdpic_p) + /* Function descriptor takes 64 bits in GOT. */ + sgotplt->size += 8; + else + sgotplt->size += 4; } } @@ -9526,7 +9568,11 @@ elf32_arm_populate_plt_entry (bfd *output_bfd, struct bfd_link_info *info, in all the symbols for which we are making plt entries. After the reserved .got.plt entries, all symbols appear in the same order as in .plt. */ - plt_index = (got_offset - got_header_size) / 4; + if (htab->fdpic_p) + /* Function descriptor takes 8 bytes. */ + plt_index = (got_offset - got_header_size) / 8; + else + plt_index = (got_offset - got_header_size) / 4; /* Calculate the address of the GOT entry. */ got_address = (sgot->output_section->vma @@ -9634,6 +9680,42 @@ elf32_arm_populate_plt_entry (bfd *output_bfd, struct bfd_link_info *info, | (tail_displacement & 0x00ffffff), ptr + 12); } + else if (htab->fdpic_p) + { + /* Fill-up Thumb stub if needed. */ + if (elf32_arm_plt_needs_thumb_stub_p (info, arm_plt)) + { + put_thumb_insn (htab, output_bfd, + elf32_arm_plt_thumb_stub[0], ptr - 4); + put_thumb_insn (htab, output_bfd, + elf32_arm_plt_thumb_stub[1], ptr - 2); + } + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[0], ptr + 0); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[1], ptr + 4); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[2], ptr + 8); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[3], ptr + 12); + bfd_put_32 (output_bfd, got_offset, ptr + 16); + + if (!(info->flags & DF_BIND_NOW)) + { + /* funcdesc_value_reloc_offset. */ + bfd_put_32 (output_bfd, + htab->root.srelplt->reloc_count * RELOC_SIZE (htab), + ptr + 20); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[6], ptr + 24); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[7], ptr + 28); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[8], ptr + 32); + put_arm_insn(htab, output_bfd, + elf32_arm_fdpic_plt_entry[9], ptr + 36); + } + } else if (using_thumb_only (htab)) { /* PR ld/16017: Generate thumb only PLT entries. */ @@ -9744,22 +9826,61 @@ elf32_arm_populate_plt_entry (bfd *output_bfd, struct bfd_link_info *info, } else { - rel.r_info = ELF32_R_INFO (dynindx, R_ARM_JUMP_SLOT); - initial_got_entry = (splt->output_section->vma - + splt->output_offset); + /* For FDPIC we will have to resolve a R_ARM_FUNCDESC_VALUE + used by PLT entry. */ + if (htab->fdpic_p) + { + rel.r_info = ELF32_R_INFO (dynindx, R_ARM_FUNCDESC_VALUE); + initial_got_entry = 0; + } + else + { + rel.r_info = ELF32_R_INFO (dynindx, R_ARM_JUMP_SLOT); + initial_got_entry = (splt->output_section->vma + + splt->output_offset); + } } /* Fill in the entry in the global offset table. */ bfd_put_32 (output_bfd, initial_got_entry, sgot->contents + got_offset); + + if (htab->fdpic_p && !(info->flags & DF_BIND_NOW)) + { + /* Setup initial funcdesc value. */ + /* FIXME: we don't support lazy binding because there is a + race condition between both words getting written and + some other thread attempting to read them. The ARM + architecture does not have an atomic 64 bit load/store + instruction that could be used to prevent it; it is + recommended that threaded FDPIC applications run with the + LD_BIND_NOW environment variable set. */ + bfd_put_32(output_bfd, plt_address + 0x18, + sgot->contents + got_offset); + bfd_put_32(output_bfd, -1 /*TODO*/, + sgot->contents + got_offset + 4); + } } if (dynindx == -1) elf32_arm_add_dynreloc (output_bfd, info, srel, &rel); else { - loc = srel->contents + plt_index * RELOC_SIZE (htab); - SWAP_RELOC_OUT (htab) (output_bfd, &rel, loc); + if (htab->fdpic_p) + { + /* For FDPIC we put PLT relocationss into .rel.got when not + lazy binding otherwise we put them in .rel.plt. For now, + we don't support lazy binding so put it in .rel.got. */ + if (info->flags & DF_BIND_NOW) + elf32_arm_add_dynreloc(output_bfd, info, htab->root.srelgot, &rel); + else + elf32_arm_add_dynreloc(output_bfd, info, htab->root.srelplt, &rel); + } + else + { + loc = srel->contents + plt_index * RELOC_SIZE (htab); + SWAP_RELOC_OUT (htab) (output_bfd, &rel, loc); + } } return TRUE; @@ -17574,6 +17695,19 @@ elf32_arm_output_plt_map_1 (output_arch_syminfo *osi, if (!elf32_arm_output_map_sym (osi, ARM_MAP_ARM, addr)) return FALSE; } + else if (htab->fdpic_p) + { + if (elf32_arm_plt_needs_thumb_stub_p (osi->info, arm_plt)) + if (!elf32_arm_output_map_sym (osi, ARM_MAP_THUMB, addr - 4)) + return FALSE; + if (!elf32_arm_output_map_sym (osi, ARM_MAP_ARM, addr)) + return FALSE; + if (!elf32_arm_output_map_sym (osi, ARM_MAP_DATA, addr + 16)) + return FALSE; + if (htab->plt_entry_size == 4 * ARRAY_SIZE(elf32_arm_fdpic_plt_entry)) + if (!elf32_arm_output_map_sym (osi, ARM_MAP_ARM, addr + 24)) + return FALSE; + } else if (using_thumb_only (htab)) { if (!elf32_arm_output_map_sym (osi, ARM_MAP_THUMB, addr)) |