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| author | H.J. Lu <hjl.tools@gmail.com> | 2018-02-27 11:34:20 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2018-02-27 11:34:29 -0800 |
| commit | f6aec96dce1ddbd8961a3aa8a2925db2021719bb (patch) | |
| tree | 0837083a3f8011754f0fa415afa4a6fb27795580 /bfd/config.in | |
| parent | 55089490f79ce1ddb9610fd6abeeaf896825fb71 (diff) | |
| download | gdb-f6aec96dce1ddbd8961a3aa8a2925db2021719bb.zip gdb-f6aec96dce1ddbd8961a3aa8a2925db2021719bb.tar.gz gdb-f6aec96dce1ddbd8961a3aa8a2925db2021719bb.tar.bz2 | |
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.
Diffstat (limited to 'bfd/config.in')
| -rw-r--r-- | bfd/config.in | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/bfd/config.in b/bfd/config.in index 75a5ff0..186741d 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 |