From 691d2e9af211ff8dd5fa8c96cb961b73a78394d7 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 18 Jan 2018 22:06:40 +1030 Subject: [PATCH] PowerPC PLT stub alignment fixes Asking for ppc32 plt call stubs to be aligned at 32 byte boundaries didn't quite work. For ld.bfd they were spaced 32 bytes apart, but only started on a 16 byte boundary. ld.gold also didn't get it right. Finding that bug made me check over the ppc64 plt stub alignment, where I found that negative values for alignment (meaning align to minimize boundary crossing) were not accepted. Since no one has complained about that, I guess I could have removed the feature from ld.bfd documentation, but I've opted instead to correct the code. I've also added an optional alignment paramenter for ppc32 --plt-align, for some consistency with gold and ppc64 ld.bfd. bfd/ * elf32-ppc.c (ppc_elf_create_glink): Correct alignment of .glink. * elf64-ppc.c (ppc64_elf_size_stubs): Handle negative plt_stub_align. (ppc64_elf_build_stubs): Likewise. gold/ * powerpc.cc (param_plt_align): New function supplying default --plt-align values. Use it.. (Stub_table::plt_call_align): ..here, and.. (Output_data_glink::global_entry_align): ..here. (Stub_table::stub_align): Correct 32-bit minimum alignment. ld/ * emultempl/ppc32elf.em: Support optional --plt-align arg. * emultempl/ppc64elf.em: Support negative --plt-align arg. --- bfd/ChangeLog | 6 ++++++ bfd/elf32-ppc.c | 7 +++++-- bfd/elf64-ppc.c | 15 +++++++++------ gold/ChangeLog | 8 ++++++++ gold/powerpc.cc | 19 ++++++++++++------- ld/ChangeLog | 5 +++++ ld/emultempl/ppc32elf.em | 13 +++++++++++-- ld/emultempl/ppc64elf.em | 4 ++-- 8 files changed, 58 insertions(+), 19 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index f1c5c413f60..3c8fcf3ab74 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,9 @@ +2018-01-18 Alan Modra + + * elf32-ppc.c (ppc_elf_create_glink): Correct alignment of .glink. + * elf64-ppc.c (ppc64_elf_size_stubs): Handle negative plt_stub_align. + (ppc64_elf_build_stubs): Likewise. + 2018-01-17 Nick Clifton * po/ru.po: Updated Russian translation. diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c index 73701d48c6f..32104a12fdf 100644 --- a/bfd/elf32-ppc.c +++ b/bfd/elf32-ppc.c @@ -3475,14 +3475,17 @@ ppc_elf_create_glink (bfd *abfd, struct bfd_link_info *info) struct ppc_elf_link_hash_table *htab = ppc_elf_hash_table (info); asection *s; flagword flags; + int p2align; flags = (SEC_ALLOC | SEC_LOAD | SEC_CODE | SEC_READONLY | SEC_HAS_CONTENTS | SEC_IN_MEMORY | SEC_LINKER_CREATED); s = bfd_make_section_anyway_with_flags (abfd, ".glink", flags); htab->glink = s; + p2align = htab->params->ppc476_workaround ? 6 : 4; + if (p2align < htab->params->plt_stub_align) + p2align = htab->params->plt_stub_align; if (s == NULL - || !bfd_set_section_alignment (abfd, s, - htab->params->ppc476_workaround ? 6 : 4)) + || !bfd_set_section_alignment (abfd, s, p2align)) return FALSE; if (!info->no_ld_generated_unwind_info) diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c index 65cf7feb391..b2d288bd4e7 100644 --- a/bfd/elf64-ppc.c +++ b/bfd/elf64-ppc.c @@ -12743,9 +12743,11 @@ ppc64_elf_size_stubs (struct bfd_link_info *info) if (htab->params->plt_stub_align != 0) for (group = htab->group; group != NULL; group = group->next) if (group->stub_sec != NULL) - group->stub_sec->size = ((group->stub_sec->size - + (1 << htab->params->plt_stub_align) - 1) - & -(1 << htab->params->plt_stub_align)); + { + int align = abs (htab->params->plt_stub_align); + group->stub_sec->size + = (group->stub_sec->size + (1 << align) - 1) & -(1 << align); + } for (group = htab->group; group != NULL; group = group->next) if (group->stub_sec != NULL @@ -13285,9 +13287,10 @@ ppc64_elf_build_stubs (struct bfd_link_info *info, if (htab->params->plt_stub_align != 0) for (group = htab->group; group != NULL; group = group->next) if ((stub_sec = group->stub_sec) != NULL) - stub_sec->size = ((stub_sec->size - + (1 << htab->params->plt_stub_align) - 1) - & -(1 << htab->params->plt_stub_align)); + { + int align = abs (htab->params->plt_stub_align); + stub_sec->size = (stub_sec->size + (1 << align) - 1) & -(1 << align); + } for (group = htab->group; group != NULL; group = group->next) if ((stub_sec = group->stub_sec) != NULL) diff --git a/gold/ChangeLog b/gold/ChangeLog index ec56a894674..b833a7b3630 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,11 @@ +2018-01-18 Alan Modra + + * powerpc.cc (param_plt_align): New function supplying default + --plt-align values. Use it.. + (Stub_table::plt_call_align): ..here, and.. + (Output_data_glink::global_entry_align): ..here. + (Stub_table::stub_align): Correct 32-bit minimum alignment. + 2018-01-17 Alan Modra * options.h (speculate_indirect_jumps): New option. diff --git a/gold/powerpc.cc b/gold/powerpc.cc index 6b65792a66f..3c38a06e83a 100644 --- a/gold/powerpc.cc +++ b/gold/powerpc.cc @@ -4186,6 +4186,15 @@ output_bctr(unsigned char* p) return p; } +template +static inline unsigned int +param_plt_align() +{ + if (!parameters->options().user_set_plt_align()) + return size == 64 ? 32 : 8; + return 1 << parameters->options().plt_align(); +} + // Stub_table holds information about plt and long branch stubs. // Stubs are built in an area following some input section determined // by group_sections(). This input section is converted to a relaxed @@ -4412,9 +4421,7 @@ class Stub_table : public Output_relaxed_input_section unsigned int stub_align() const { - unsigned int min_align = 4; - if (!parameters->options().user_set_plt_align()) - return size == 64 ? 32 : min_align; + unsigned int min_align = size == 64 ? 32 : 16; unsigned int user_align = 1 << parameters->options().plt_align(); return std::max(user_align, min_align); } @@ -4483,7 +4490,7 @@ class Stub_table : public Output_relaxed_input_section unsigned int plt_call_align(unsigned int bytes) const { - unsigned int align = this->stub_align(); + unsigned int align = param_plt_align(); return (bytes + align - 1) & -align; } @@ -4926,9 +4933,7 @@ class Output_data_glink : public Output_section_data unsigned int global_entry_align(unsigned int off) const { - unsigned int align = 1 << parameters->options().plt_align(); - if (!parameters->options().user_set_plt_align()) - align = size == 64 ? 32 : 4; + unsigned int align = param_plt_align(); return (off + align - 1) & -align; } diff --git a/ld/ChangeLog b/ld/ChangeLog index 9ee555baa7a..38017053026 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,8 @@ +2018-01-18 Alan Modra + + * emultempl/ppc32elf.em: Support optional --plt-align arg. + * emultempl/ppc64elf.em: Support negative --plt-align arg. + 2018-01-17 Alan Modra * emultempl/ppc32elf.em (params): Init new field. diff --git a/ld/emultempl/ppc32elf.em b/ld/emultempl/ppc32elf.em index 4e71a7802cc..3007fb2f801 100644 --- a/ld/emultempl/ppc32elf.em +++ b/ld/emultempl/ppc32elf.em @@ -271,7 +271,7 @@ if test -z "$VXWORKS_BASE_EM_FILE" ; then { "bss-plt", no_argument, NULL, OPTION_OLD_PLT }, { "speculate-indirect-jumps", no_argument, NULL, OPTION_SPECULATE_INDIRECT_JUMPS }, { "no-speculate-indirect-jumps", no_argument, NULL, OPTION_NO_SPECULATE_INDIRECT_JUMPS }, - { "plt-align", no_argument, NULL, OPTION_PLT_ALIGN }, + { "plt-align", optional_argument, NULL, OPTION_PLT_ALIGN }, { "no-plt-align", no_argument, NULL, OPTION_NO_PLT_ALIGN }, { "sdata-got", no_argument, NULL, OPTION_OLD_GOT },' fi @@ -369,7 +369,16 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}' break; case OPTION_PLT_ALIGN: - params.plt_stub_align = 5; + if (optarg != NULL) + { + char *end; + unsigned long val = strtoul (optarg, &end, 0); + if (*end || val > 5) + einfo (_("%P%F: invalid --plt-align `%s'\''\n"), optarg); + params.plt_stub_align = val; + } + else + params.plt_stub_align = 5; break; case OPTION_NO_PLT_ALIGN: diff --git a/ld/emultempl/ppc64elf.em b/ld/emultempl/ppc64elf.em index c7c27b04152..0baa424339a 100644 --- a/ld/emultempl/ppc64elf.em +++ b/ld/emultempl/ppc64elf.em @@ -872,8 +872,8 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}' if (optarg != NULL) { char *end; - unsigned long val = strtoul (optarg, &end, 0); - if (*end || val > 8) + long val = strtol (optarg, &end, 0); + if (*end || (unsigned long) val + 8 > 16) einfo (_("%P%F: invalid --plt-align `%s'\''\n"), optarg); params.plt_stub_align = val; } -- 2.30.2