From f6aec96dce1ddbd8961a3aa8a2925db2021719bb Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 27 Feb 2018 11:34:20 -0800 Subject: [PATCH] ld: Add --enable-separate-code This patch adds --enable-separate-code to ld configure to turn on -z separate-code by default and enables it by default for Linux/x86. This avoids mixing code pages with data to improve cache performance as well as security. To reduce x86-64 executable and shared object sizes, the maximum page size is reduced from 2MB to 4KB when -z separate-code is turned on by default. Note: -z max-page-size= can be used to set the maximum page size. We compared SPEC CPU 2017 performance before and after this change on Skylake server. There are no any significant performance changes. Everything is mostly below +/-1%. bfd/ * config.in: Regenerated. * configure: Likewise. * configure.ac: Add --enable-separate-code. (DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED. Default to 1 for Linux/x86 targets, * elf64-x86-64.c (ELF_MAXPAGESIZE): Set to 0x1000 if DEFAULT_LD_Z_SEPARATE_CODE is 1. ld/ * NEWS: Mention --enable-separate-code. * configure.ac: Add --enable-separate-code. (DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED. * configure.tgt: Default ac_default_ld_z_separate_code to 1 for Linux/x86 targets. * config.in: Regenerated. * configure: Likewise. * emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set link_info.separate_code DEFAULT_LD_Z_SEPARATE_CODE. --- bfd/ChangeLog | 10 ++++++++++ bfd/config.in | 4 ++++ bfd/configure | 33 +++++++++++++++++++++++++++++++-- bfd/configure.ac | 24 ++++++++++++++++++++++++ bfd/elf64-x86-64.c | 12 ++++++++++-- ld/ChangeLog | 12 ++++++++++++ ld/NEWS | 5 +++++ ld/config.in | 4 ++++ ld/configure | 26 ++++++++++++++++++++++++-- ld/configure.ac | 17 +++++++++++++++++ ld/configure.tgt | 9 +++++++++ ld/emultempl/elf32.em | 1 + 12 files changed, 151 insertions(+), 6 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 5c2a888cd00..59f7c9cfd48 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,13 @@ +2018-02-27 H.J. Lu + + * config.in: Regenerated. + * configure: Likewise. + * configure.ac: Add --enable-separate-code. + (DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED. Default + to 1 for Linux/x86 targets, + * elf64-x86-64.c (ELF_MAXPAGESIZE): Set to 0x1000 if + DEFAULT_LD_Z_SEPARATE_CODE is 1. + 2018-02-27 Nick Clifton * aout-cris.c (swap_ext_reloc_out): Standadize error/warning diff --git a/bfd/config.in b/bfd/config.in index 75a5ff015ed..186741d6128 100644 --- a/bfd/config.in +++ b/bfd/config.in @@ -10,6 +10,10 @@ /* Name of host specific core header file to include in elf.c. */ #undef CORE_HEADER +/* Define to 1 if you want to enable -z separate-code in ELF linker by + default. */ +#undef DEFAULT_LD_Z_SEPARATE_CODE + /* Define to 1 if translation of program messages to the user's native language is requested. */ #undef ENABLE_NLS diff --git a/bfd/configure b/bfd/configure index 6c2b24ebe3d..d1fe335530c 100755 --- a/bfd/configure +++ b/bfd/configure @@ -793,6 +793,7 @@ enable_targets enable_64_bit_archive with_mmap enable_secureplt +enable_separate_code enable_leading_mingw64_underscores with_separate_debug_dir with_pkgversion @@ -1446,6 +1447,7 @@ Optional Features: --enable-targets alternative target configurations --enable-64-bit-archive force 64-bit archives --enable-secureplt Default to creating read-only plt entries + --enable-separate-code enable -z separate-code in ELF linker by default --enable-leading-mingw64-underscores Enable leading underscores on 64 bit mingw targets --enable-werror treat compile warnings as errors @@ -11428,7 +11430,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11431 "configure" +#line 11433 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -11534,7 +11536,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11537 "configure" +#line 11539 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -12171,6 +12173,33 @@ $as_echo "#define USE_SECUREPLT 1" >>confdefs.h fi +# Decide if -z separate-code should be enabled in ELF linker by default. +ac_default_ld_z_separate_code=unset +# Check whether --enable-separate-code was given. +if test "${enable_separate_code+set}" = set; then : + enableval=$enable_separate_code; case "${enableval}" in + yes) ac_default_ld_z_separate_code=1 ;; + no) ac_default_ld_z_separate_code=0 ;; +esac +fi + +# Enable -z separate-code by default for Linux/x86. +case "${target}" in +i3-786-*-linux-* | x86_64-*-linux-*) + if test ${ac_default_ld_z_separate_code} = unset; then + ac_default_ld_z_separate_code=1 + fi + ;; +esac +if test "${ac_default_ld_z_separate_code}" = unset; then + ac_default_ld_z_separate_code=0 +fi + +cat >>confdefs.h <<_ACEOF +#define DEFAULT_LD_Z_SEPARATE_CODE $ac_default_ld_z_separate_code +_ACEOF + + # Check whether --enable-leading-mingw64-underscores was given. if test "${enable_leading_mingw64_underscores+set}" = set; then : enableval=$enable_leading_mingw64_underscores; diff --git a/bfd/configure.ac b/bfd/configure.ac index 2342f3faeac..20e2c022e8a 100644 --- a/bfd/configure.ac +++ b/bfd/configure.ac @@ -97,6 +97,30 @@ if test $use_secureplt = true; then [Define if we should default to creating read-only plt entries]) fi +# Decide if -z separate-code should be enabled in ELF linker by default. +ac_default_ld_z_separate_code=unset +AC_ARG_ENABLE(separate-code, + AS_HELP_STRING([--enable-separate-code], + [enable -z separate-code in ELF linker by default]), +[case "${enableval}" in + yes) ac_default_ld_z_separate_code=1 ;; + no) ac_default_ld_z_separate_code=0 ;; +esac]) +# Enable -z separate-code by default for Linux/x86. +case "${target}" in +i[3-7]86-*-linux-* | x86_64-*-linux-*) + if test ${ac_default_ld_z_separate_code} = unset; then + ac_default_ld_z_separate_code=1 + fi + ;; +esac +if test "${ac_default_ld_z_separate_code}" = unset; then + ac_default_ld_z_separate_code=0 +fi +AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_SEPARATE_CODE, + $ac_default_ld_z_separate_code, + [Define to 1 if you want to enable -z separate-code in ELF linker by default.]) + AC_ARG_ENABLE(leading-mingw64-underscores, AS_HELP_STRING([--enable-leading-mingw64-underscores], [Enable leading underscores on 64 bit mingw targets]), diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index 02a3d37e43c..7016964aceb 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -4942,7 +4942,11 @@ elf_x86_64_special_sections[]= #define ELF_ARCH bfd_arch_i386 #define ELF_TARGET_ID X86_64_ELF_DATA #define ELF_MACHINE_CODE EM_X86_64 -#define ELF_MAXPAGESIZE 0x200000 +#if DEFAULT_LD_Z_SEPARATE_CODE +# define ELF_MAXPAGESIZE 0x1000 +#else +# define ELF_MAXPAGESIZE 0x200000 +#endif #define ELF_MINPAGESIZE 0x1000 #define ELF_COMMONPAGESIZE 0x1000 @@ -5335,7 +5339,11 @@ elf64_l1om_elf_object_p (bfd *abfd) #undef ELF_MAXPAGESIZE #undef ELF_MINPAGESIZE #undef ELF_COMMONPAGESIZE -#define ELF_MAXPAGESIZE 0x200000 +#if DEFAULT_LD_Z_SEPARATE_CODE +# define ELF_MAXPAGESIZE 0x1000 +#else +# define ELF_MAXPAGESIZE 0x200000 +#endif #define ELF_MINPAGESIZE 0x1000 #define ELF_COMMONPAGESIZE 0x1000 #undef elf_backend_plt_alignment diff --git a/ld/ChangeLog b/ld/ChangeLog index d117b7e4741..07c86efc061 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,15 @@ +2018-02-27 H.J. Lu + + * NEWS: Mention --enable-separate-code. + * configure.ac: Add --enable-separate-code. + (DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED. + * configure.tgt: Default ac_default_ld_z_separate_code to 1 for + Linux/x86 targets. + * config.in: Regenerated. + * configure: Likewise. + * emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set + link_info.separate_code DEFAULT_LD_Z_SEPARATE_CODE. + 2018-02-26 Alan Modra * emulparams/call_nop.sh, * emulparams/cet.sh, diff --git a/ld/NEWS b/ld/NEWS index eafcaf33cb7..75f8100f87a 100644 --- a/ld/NEWS +++ b/ld/NEWS @@ -1,5 +1,10 @@ -*- text -*- +* Add a configure option --enable-separate-code to decide whether + -z separate-code should be enabled in ELF linker by default. Default + to yes for Linux/x86 targets. Note that -z separate-code can increase + disk and memory size. + Changes in 2.30: * Add -z separate-code to generate separate code PT_LOAD segment. diff --git a/ld/config.in b/ld/config.in index a846743da6b..b227a539846 100644 --- a/ld/config.in +++ b/ld/config.in @@ -19,6 +19,10 @@ /* Define to 1 if you want to enable -z relro in ELF linker by default. */ #undef DEFAULT_LD_Z_RELRO +/* Define to 1 if you want to enable -z separate-code in ELF linker by + default. */ +#undef DEFAULT_LD_Z_SEPARATE_CODE + /* Define to 1 if you want to set DT_RUNPATH instead of DT_RPATH by default. */ #undef DEFAULT_NEW_DTAGS diff --git a/ld/configure b/ld/configure index 17604bb91be..38f9739126f 100755 --- a/ld/configure +++ b/ld/configure @@ -790,6 +790,7 @@ enable_got enable_compressed_debug_sections enable_new_dtags enable_relro +enable_separate_code enable_default_hash_style enable_werror enable_build_warnings @@ -1451,6 +1452,7 @@ Optional Features: compress debug sections by default] --enable-new-dtags set DT_RUNPATH instead of DT_RPATH by default] --enable-relro enable -z relro in ELF linker by default + --enable-separate-code enable -z separate-code in ELF linker by default --enable-default-hash-style={sysv,gnu,both} use this default hash style --enable-werror treat compile warnings as errors @@ -11725,7 +11727,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11728 "configure" +#line 11730 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -11831,7 +11833,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 11834 "configure" +#line 11836 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -15567,6 +15569,17 @@ if test "${enable_relro+set}" = set; then : esac fi +# Decide if -z separate-code should be enabled in ELF linker by default. +ac_default_ld_z_separate_code=unset +# Check whether --enable-separate-code was given. +if test "${enable_separate_code+set}" = set; then : + enableval=$enable_separate_code; case "${enableval}" in + yes) ac_default_ld_z_separate_code=1 ;; + no) ac_default_ld_z_separate_code=0 ;; +esac +fi + + # Decide which "--hash-style" to use by default # Provide a configure time option to override our default. # Check whether --enable-default-hash-style was given. @@ -17258,6 +17271,15 @@ cat >>confdefs.h <<_ACEOF _ACEOF +if test "${ac_default_ld_z_separate_code}" = unset; then + ac_default_ld_z_separate_code=0 +fi + +cat >>confdefs.h <<_ACEOF +#define DEFAULT_LD_Z_SEPARATE_CODE $ac_default_ld_z_separate_code +_ACEOF + + cat >>confdefs.h <<_ACEOF #define DEFAULT_EMIT_SYSV_HASH $ac_default_emit_sysv_hash diff --git a/ld/configure.ac b/ld/configure.ac index 6da8c8e50f1..35529268db8 100644 --- a/ld/configure.ac +++ b/ld/configure.ac @@ -177,6 +177,16 @@ AC_ARG_ENABLE(relro, no) ac_default_ld_z_relro=0 ;; esac])dnl +# Decide if -z separate-code should be enabled in ELF linker by default. +ac_default_ld_z_separate_code=unset +AC_ARG_ENABLE(separate-code, + AS_HELP_STRING([--enable-separate-code], + [enable -z separate-code in ELF linker by default]), +[case "${enableval}" in + yes) ac_default_ld_z_separate_code=1 ;; + no) ac_default_ld_z_separate_code=0 ;; +esac]) + # Decide which "--hash-style" to use by default # Provide a configure time option to override our default. AC_ARG_ENABLE([default-hash-style], @@ -434,6 +444,13 @@ AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_RELRO, $ac_default_ld_z_relro, [Define to 1 if you want to enable -z relro in ELF linker by default.]) +if test "${ac_default_ld_z_separate_code}" = unset; then + ac_default_ld_z_separate_code=0 +fi +AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_SEPARATE_CODE, + $ac_default_ld_z_separate_code, + [Define to 1 if you want to enable -z separate-code in ELF linker by default.]) + AC_DEFINE_UNQUOTED([DEFAULT_EMIT_SYSV_HASH], [$ac_default_emit_sysv_hash], [Define to 1 if you want to emit sysv hash in the ELF linker by default.]) diff --git a/ld/configure.tgt b/ld/configure.tgt index 6183a85b3d1..7897448e643 100644 --- a/ld/configure.tgt +++ b/ld/configure.tgt @@ -968,3 +968,12 @@ frv-*-* | hppa*-*-* | ia64-*-* | mips*-*-*) fi ;; esac + +# Enable -z separate-code by default for Linux/x86. +case "${target}" in +i[3-7]86-*-linux-* | x86_64-*-linux-*) + if test ${ac_default_ld_z_separate_code} = unset; then + ac_default_ld_z_separate_code=1 + fi + ;; +esac diff --git a/ld/emultempl/elf32.em b/ld/emultempl/elf32.em index aae9d1f6259..9b8971eac48 100644 --- a/ld/emultempl/elf32.em +++ b/ld/emultempl/elf32.em @@ -106,6 +106,7 @@ gld${EMULATION_NAME}_before_parse (void) `if test -n "$CALL_NOP_BYTE" ; then echo link_info.call_nop_byte = $CALL_NOP_BYTE; fi`; link_info.check_relocs_after_open_input = TRUE; link_info.relro = DEFAULT_LD_Z_RELRO; + link_info.separate_code = DEFAULT_LD_Z_SEPARATE_CODE; } EOF -- 2.30.2