From 1be5d8d3bbec4c9a112114993ac5c85b2b26c4c4 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Wed, 17 Jan 2018 14:19:08 +1030 Subject: PowerPC PLT speculative execution barriers Spectre variant 2 mitigation for PowerPC and PowerPC64. bfd/ * elf32-ppc.c (GLINK_ENTRY_SIZE): Handle speculation barrier. (CRSETEQ, BEQCTRM): Define. (is_nonpic_glink_stub): Don't check bctr. (ppc_elf_link_hash_table_create): Init new ppc_elf_params field. (ppc_elf_relax_section): Size speculation barrier. (output_bctr): New function. (write_glink_stub): Use output_bctr. (ppc_elf_relocate_section): Use output_bctr for long branch stub. (ppc_elf_finish_dynamic_symbol): Likewise. (ppc_elf_finish_dynamic_sections): Use output_bctr. * elf32-ppc.h (struct ppc_elf_params): Add speculate_indirect_jumps. * elf64-ppc.c (CRSETEQ, BEQCTRM, BEQCTRLM): Define. (GLINK_PLTRESOLVE_SIZE): Size speculation barrier. (size_global_entry_stubs): Handle speculation barrier sizing. (plt_stub_size): Likewise. (output_bctr): New function. (build_plt_stub, build_tls_get_addr_stub): Output speculation barrier. (ppc_build_one_stub): Likewise for ppc_stub_plt_branch. (ppc_size_one_stub): Size speculation barrier in ppc_stub_plt_branch. (build_global_entry_stubs): Output speculation barrier. (ppc64_elf_build_stubs): Likewise in __glink_PLTresolve stub. * elf64-ppc.h (struct ppc64_elf_params): Add speculate_indirect_jumps. gold/ * options.h (speculate_indirect_jumps): New option. * powerpc.cc (beqctrm, beqctrlm, crseteq): New insn constants. (output_bctr): New function. (Stub_table::plt_call_size): Add space for speculation barrier. (Stub_table::branch_stub_size): Likewise. (Output_data_glink::pltresolve_size): Likewise. (Stub_table::do_write): Output speculation barriers. ld/ * emultempl/ppc32elf.em (params): Init new field. (OPTION_SPECULATE_INDIRECT_JUMPS): Define. (OPTION_NO_SPECULATE_INDIRECT_JUMPS): Define. (PARSE_AND_LIST_LONGOPTS): Handle new options. (PARSE_AND_LIST_ARGS_CASES): Likewise. (PARSE_AND_LIST_OPTIONS): Likewise. * emultempl/ppc64elf.em (params): Init new field. (OPTION_SPECULATE_INDIRECT_JUMPS): Define. (OPTION_NO_SPECULATE_INDIRECT_JUMPS): Define. (PARSE_AND_LIST_LONGOPTS): Handle --speculate-indirect-jumps. (PARSE_AND_LIST_OPTIONS): Likewise. (PARSE_AND_LIST_ARGS_CASES): Likewise. * ld.texinfo (--no-plt-thread-safe): Correct itemx. (--speculate-indirect-jumps): Document. * testsuite/ld-powerpc/elfv2exe.d, * testsuite/ld-powerpc/elfv2so.d, * testsuite/ld-powerpc/relbrlt.d, * testsuite/ld-powerpc/powerpc.exp: Disable plt alignment and speculation barriers on various tests. --- ld/emultempl/ppc32elf.em | 20 +++++++++++++++++++- ld/emultempl/ppc64elf.em | 22 ++++++++++++++++++++-- 2 files changed, 39 insertions(+), 3 deletions(-) (limited to 'ld/emultempl') diff --git a/ld/emultempl/ppc32elf.em b/ld/emultempl/ppc32elf.em index 70dd5a0..4e71a78 100644 --- a/ld/emultempl/ppc32elf.em +++ b/ld/emultempl/ppc32elf.em @@ -38,7 +38,7 @@ static int notlsopt = 0; /* Choose the correct place for .got. */ static int old_got = 0; -static struct ppc_elf_params params = { PLT_UNSET, 0, -1, +static struct ppc_elf_params params = { PLT_UNSET, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0 }; static void @@ -246,6 +246,8 @@ enum ppc32_opt OPTION_NO_TLS_GET_ADDR_OPT, OPTION_NEW_PLT, OPTION_OLD_PLT, + OPTION_SPECULATE_INDIRECT_JUMPS, + OPTION_NO_SPECULATE_INDIRECT_JUMPS, OPTION_PLT_ALIGN, OPTION_NO_PLT_ALIGN, OPTION_OLD_GOT, @@ -267,6 +269,8 @@ if test -z "$VXWORKS_BASE_EM_FILE" ; then PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}' { "secure-plt", no_argument, NULL, OPTION_NEW_PLT }, { "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 }, { "no-plt-align", no_argument, NULL, OPTION_NO_PLT_ALIGN }, { "sdata-got", no_argument, NULL, OPTION_OLD_GOT },' @@ -300,6 +304,12 @@ if test -z "$VXWORKS_BASE_EM_FILE" ; then --bss-plt Force old-style BSS PLT.\n" )); fprintf (file, _("\ + --speculate-indirect-jumps PLT call stubs without speculation barrier.\n" + )); + fprintf (file, _("\ + --no-speculate-indirect-jumps PLT call stubs with speculation barrier.\n" + )); + fprintf (file, _("\ --plt-align Align PLT call stubs to fit cache lines.\n" )); fprintf (file, _("\ @@ -350,6 +360,14 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}' params.plt_style = PLT_OLD; break; + case OPTION_SPECULATE_INDIRECT_JUMPS: + params.speculate_indirect_jumps = 1; + break; + + case OPTION_NO_SPECULATE_INDIRECT_JUMPS: + params.speculate_indirect_jumps = 0; + break; + case OPTION_PLT_ALIGN: params.plt_stub_align = 5; break; diff --git a/ld/emultempl/ppc64elf.em b/ld/emultempl/ppc64elf.em index 840bd44..c7c27b0 100644 --- a/ld/emultempl/ppc64elf.em +++ b/ld/emultempl/ppc64elf.em @@ -38,7 +38,7 @@ static struct ppc64_elf_params params = { NULL, &ppc_layout_sections_again, 1, -1, 0, ${DEFAULT_PLT_STATIC_CHAIN-0}, -1, 5, - -1, 0, -1, -1, 0}; + -1, 1, 0, -1, -1, 0}; /* Fake input file for stubs. */ static lang_input_statement_type *stub_file; @@ -692,6 +692,8 @@ enum ppc64_opt OPTION_NO_PLT_STATIC_CHAIN, OPTION_PLT_THREAD_SAFE, OPTION_NO_PLT_THREAD_SAFE, + OPTION_SPECULATE_INDIRECT_JUMPS, + OPTION_NO_SPECULATE_INDIRECT_JUMPS, OPTION_PLT_ALIGN, OPTION_NO_PLT_ALIGN, OPTION_PLT_LOCALENTRY, @@ -719,6 +721,8 @@ PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}' { "no-plt-static-chain", no_argument, NULL, OPTION_NO_PLT_STATIC_CHAIN }, { "plt-thread-safe", no_argument, NULL, OPTION_PLT_THREAD_SAFE }, { "no-plt-thread-safe", no_argument, NULL, OPTION_NO_PLT_THREAD_SAFE }, + { "speculate-indirect-jumps", no_argument, NULL, OPTION_SPECULATE_INDIRECT_JUMPS }, + { "no-speculate-indirect-jumps", no_argument, NULL, OPTION_NO_SPECULATE_INDIRECT_JUMPS }, { "plt-align", optional_argument, NULL, OPTION_PLT_ALIGN }, { "no-plt-align", no_argument, NULL, OPTION_NO_PLT_ALIGN }, { "plt-localentry", optional_argument, NULL, OPTION_PLT_LOCALENTRY }, @@ -760,7 +764,13 @@ PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}' --plt-thread-safe PLT call stubs with load-load barrier.\n" )); fprintf (file, _("\ - --no-plt-thread-safe PLT call stubs without barrier.\n" + --no-plt-thread-safe PLT call stubs without load-load barrier.\n" + )); + fprintf (file, _("\ + --speculate-indirect-jumps PLT call stubs without speculation barrier.\n" + )); + fprintf (file, _("\ + --no-speculate-indirect-jumps PLT call stubs with speculation barrier.\n" )); fprintf (file, _("\ --plt-align [=] Align PLT call stubs to fit cache lines.\n" @@ -850,6 +860,14 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}' params.plt_thread_safe = 0; break; + case OPTION_SPECULATE_INDIRECT_JUMPS: + params.speculate_indirect_jumps = 1; + break; + + case OPTION_NO_SPECULATE_INDIRECT_JUMPS: + params.speculate_indirect_jumps = 0; + break; + case OPTION_PLT_ALIGN: if (optarg != NULL) { -- cgit v1.1