From 9a926d55ab4b6667f6c35b518d59b902fe490d9d Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 2 Dec 2014 15:14:28 -0800 Subject: [PATCH] X86-64: Allow copy relocs for building PIE This patch allows copy relocs for non-GOT pc-relative relocation in PIE. bfd/ * elf64-x86-64.c (elf_x86_64_create_dynamic_sections): Always allow copy relocs for building executables. (elf_x86_64_check_relocs): Allow copy relocs for non-GOT pc-relative relocation in shared object. (elf_x86_64_adjust_dynamic_symbol): Allocate copy relocs for PIE. (elf_x86_64_relocate_section): Don't copy a pc-relative relocation into the output file if the symbol needs copy reloc. ld/testsuite/ * ld-x86-64/copyreloc-lib.c: New file. * ld-x86-64/copyreloc-main.c: Likewise. * ld-x86-64/copyreloc-main.out: Likewise. * ld-x86-64/copyreloc-main1.rd: Likewise. * ld-x86-64/copyreloc-main2.rd: Likewise. * ld-x86-64/x86-64.exp: Run copyreloc tests. --- bfd/ChangeLog | 11 ++++++ bfd/elf64-x86-64.c | 46 +++++++++++++++++------ ld/testsuite/ChangeLog | 10 +++++ ld/testsuite/ld-x86-64/copyreloc-lib.c | 1 + ld/testsuite/ld-x86-64/copyreloc-main.c | 7 ++++ ld/testsuite/ld-x86-64/copyreloc-main.out | 0 ld/testsuite/ld-x86-64/copyreloc-main1.rd | 3 ++ ld/testsuite/ld-x86-64/copyreloc-main2.rd | 4 ++ ld/testsuite/ld-x86-64/x86-64.exp | 32 ++++++++++++++++ 9 files changed, 103 insertions(+), 11 deletions(-) create mode 100644 ld/testsuite/ld-x86-64/copyreloc-lib.c create mode 100644 ld/testsuite/ld-x86-64/copyreloc-main.c create mode 100644 ld/testsuite/ld-x86-64/copyreloc-main.out create mode 100644 ld/testsuite/ld-x86-64/copyreloc-main1.rd create mode 100644 ld/testsuite/ld-x86-64/copyreloc-main2.rd diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 010cf555219..434db3113a6 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,14 @@ +2014-12-02 H.J. Lu + + * elf64-x86-64.c (elf_x86_64_create_dynamic_sections): Always + allow copy relocs for building executables. + (elf_x86_64_check_relocs): Allow copy relocs for non-GOT + pc-relative relocation in shared object. + (elf_x86_64_adjust_dynamic_symbol): Allocate copy relocs for + PIE. + (elf_x86_64_relocate_section): Don't copy a pc-relative + relocation into the output file if the symbol needs copy reloc. + 2014-12-02 Andrew Bennett * elfxx-mips.c (mips_elf_calculate_relocation): Only check for diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index b10c0c14a8b..60d2d59910b 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -1060,13 +1060,29 @@ elf_x86_64_create_dynamic_sections (bfd *dynobj, return FALSE; htab->sdynbss = bfd_get_linker_section (dynobj, ".dynbss"); - if (!info->shared) - htab->srelbss = bfd_get_linker_section (dynobj, ".rela.bss"); - - if (!htab->sdynbss - || (!info->shared && !htab->srelbss)) + if (!htab->sdynbss) abort (); + if (info->executable) + { + /* Always allow copy relocs for building executables. */ + asection *s; + s = bfd_get_linker_section (dynobj, ".rela.bss"); + if (s == NULL) + { + const struct elf_backend_data *bed = get_elf_backend_data (dynobj); + s = bfd_make_section_anyway_with_flags (dynobj, + ".rela.bss", + (bed->dynamic_sec_flags + | SEC_READONLY)); + if (s == NULL + || ! bfd_set_section_alignment (dynobj, s, + bed->s->log_file_align)) + return FALSE; + } + htab->srelbss = s; + } + if (!info->no_ld_generated_unwind_info && htab->plt_eh_frame == NULL && htab->elf.splt != NULL) @@ -1939,7 +1955,8 @@ do_size: storing information in the relocs_copied field of the hash table entry. A similar situation occurs when creating shared libraries and symbol visibility changes render the - symbol local. + symbol local. We allow copy relocs for non-GOT pc-relative + relocation. If on the other hand, we are creating an executable, we may need to keep relocations for symbols satisfied by a @@ -1949,6 +1966,7 @@ do_size: && (sec->flags & SEC_ALLOC) != 0 && (! IS_X86_64_PCREL_TYPE (r_type) || (h != NULL + && !h->non_got_ref && (! SYMBOLIC_BIND (info, h) || h->root.type == bfd_link_hash_defweak || !h->def_regular)))) @@ -2369,7 +2387,7 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info, only references to the symbol are via the global offset table. For such cases we need not do anything here; the relocations will be handled correctly by relocate_section. */ - if (info->shared) + if (!info->executable) return TRUE; /* If there are no references to this symbol that do not use the @@ -2384,7 +2402,7 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info, return TRUE; } - if (ELIMINATE_COPY_RELOCS) + if (ELIMINATE_COPY_RELOCS && !info->shared) { eh = (struct elf_x86_64_link_hash_entry *) h; for (p = eh->dyn_relocs; p != NULL; p = p->next) @@ -4035,10 +4053,11 @@ elf_x86_64_relocate_section (bfd *output_bfd, defined locally or for a branch. */ fail = !h->def_regular && !branch; } - else + else if (!h->needs_copy) { - /* Symbol isn't referenced locally. We only allow - branch to symbol with non-default visibility. */ + /* Symbol doesn't need copy reloc and isn't referenced + locally. We only allow branch to symbol with + non-default visibility. */ fail = (!branch || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT); } @@ -4092,7 +4111,12 @@ direct: if ((input_section->flags & SEC_ALLOC) == 0) break; + /* Don't copy a pc-relative relocation into the output file + if the symbol needs copy reloc. */ if ((info->shared + && !(h != NULL + && h->needs_copy + && IS_X86_64_PCREL_TYPE (r_type)) && (h == NULL || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT || h->root.type != bfd_link_hash_undefweak) diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog index de784f798ea..70201adffbb 100644 --- a/ld/testsuite/ChangeLog +++ b/ld/testsuite/ChangeLog @@ -1,3 +1,13 @@ +2014-12-02 H.J. Lu + + * ld-x86-64/copyreloc-lib.c: New file. + * ld-x86-64/copyreloc-main.c: Likewise. + * ld-x86-64/copyreloc-main.out: Likewise. + * ld-x86-64/copyreloc-main1.rd: Likewise. + * ld-x86-64/copyreloc-main2.rd: Likewise. + + * ld-x86-64/x86-64.exp: Run copyreloc tests. + 2014-12-02 Andrew Bennett * ld-mips-elf/mips-elf.exp: Add undefined weak overflow diff --git a/ld/testsuite/ld-x86-64/copyreloc-lib.c b/ld/testsuite/ld-x86-64/copyreloc-lib.c new file mode 100644 index 00000000000..cbbc5e245eb --- /dev/null +++ b/ld/testsuite/ld-x86-64/copyreloc-lib.c @@ -0,0 +1 @@ +int a_glob = 2; diff --git a/ld/testsuite/ld-x86-64/copyreloc-main.c b/ld/testsuite/ld-x86-64/copyreloc-main.c new file mode 100644 index 00000000000..430eefb473c --- /dev/null +++ b/ld/testsuite/ld-x86-64/copyreloc-main.c @@ -0,0 +1,7 @@ +extern int a_glob; + +int +main (void) +{ + return a_glob != 2; +} diff --git a/ld/testsuite/ld-x86-64/copyreloc-main.out b/ld/testsuite/ld-x86-64/copyreloc-main.out new file mode 100644 index 00000000000..e69de29bb2d diff --git a/ld/testsuite/ld-x86-64/copyreloc-main1.rd b/ld/testsuite/ld-x86-64/copyreloc-main1.rd new file mode 100644 index 00000000000..dcb52dce9ec --- /dev/null +++ b/ld/testsuite/ld-x86-64/copyreloc-main1.rd @@ -0,0 +1,3 @@ +#... +[0-9a-f ]+R_X86_64_COPY+[0-9a-f ]+ +a_glob \+ 0 +#... diff --git a/ld/testsuite/ld-x86-64/copyreloc-main2.rd b/ld/testsuite/ld-x86-64/copyreloc-main2.rd new file mode 100644 index 00000000000..d78ea2f7cca --- /dev/null +++ b/ld/testsuite/ld-x86-64/copyreloc-main2.rd @@ -0,0 +1,4 @@ +#failif +#... +[0-9a-f ]+R_X86_64_NONE.* +#... diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp index 886469b3e6f..91c9dd939c0 100644 --- a/ld/testsuite/ld-x86-64/x86-64.exp +++ b/ld/testsuite/ld-x86-64/x86-64.exp @@ -392,6 +392,30 @@ if { [isnative] && [which $CC] != 0 } { {{readelf {-Wr} plt-main.rd}} \ "plt-main" \ ] \ + [list \ + "Build copyreloc-lib.so" \ + "-shared" \ + "-fPIC" \ + { copyreloc-lib.c } \ + {} \ + "copyreloc-lib.so" \ + ] \ + [list \ + "Build copyreloc-main with PIE without -fPIE (1)" \ + "tmpdir/copyreloc-lib.so -pie" \ + "" \ + { copyreloc-main.c } \ + {{readelf {-Wr} copyreloc-main1.rd}} \ + "copyreloc-main" \ + ] \ + [list \ + "Build copyreloc-main with PIE without -fPIE (2)" \ + "tmpdir/copyreloc-lib.so -pie" \ + "" \ + { copyreloc-main.c } \ + {{readelf {-Wr} copyreloc-main2.rd}} \ + "copyreloc-main" \ + ] \ ] run_ld_link_exec_tests [] [list \ @@ -414,6 +438,14 @@ if { [isnative] && [which $CC] != 0 } { "plt-main.out" \ "-fPIC" \ ] \ + [list \ + "Run copyreloc-main with PIE without -fPIE" \ + "tmpdir/copyreloc-lib.so -pie" \ + "" \ + { copyreloc-main.c } \ + "copyreloc-main" \ + "copyreloc-main.out" \ + ] \ ] if { [istarget "x86_64-*-linux*"] \ -- 2.30.2