From a0dd512cbcc1db29b0ddce80cedadbf2c2af49b7 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 26 Nov 2019 14:48:56 +0100 Subject: x86: Assume --enable-cet if GCC defaults to CET [BZ #25225] This links in CET support if GCC defaults to CET. Otherwise, __CET__ is defined, yet CET functionality is not compiled and linked into the dynamic loader, resulting in a linker failure due to undefined references to _dl_cet_check and _dl_open_check. --- configure | 23 ++++++++++++++++++++++- configure.ac | 9 ++++++++- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/configure b/configure index 2f44b66656..b959d2d988 100755 --- a/configure +++ b/configure @@ -3777,11 +3777,32 @@ else fi +cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ + +int +main () +{ + +#ifndef __CET__ +#error no CET compiler support +#endif + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + libc_cv_compiler_default_cet=yes +else + libc_cv_compiler_default_cet=no +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + # Check whether --enable-cet was given. if test "${enable_cet+set}" = set; then : enableval=$enable_cet; enable_cet=$enableval else - enable_cet=no + enable_cet=$libc_cv_compiler_default_cet fi diff --git a/configure.ac b/configure.ac index e69c88c543..49b900c1ed 100644 --- a/configure.ac +++ b/configure.ac @@ -473,11 +473,18 @@ AC_ARG_ENABLE([mathvec], [build_mathvec=$enableval], [build_mathvec=notset]) +AC_TRY_COMPILE([], [ +#ifndef __CET__ +# error no CET compiler support +#endif], + [libc_cv_compiler_default_cet=yes], + [libc_cv_compiler_default_cet=no]) + AC_ARG_ENABLE([cet], AC_HELP_STRING([--enable-cet], [enable Intel Control-flow Enforcement Technology (CET), x86 only]), [enable_cet=$enableval], - [enable_cet=no]) + [enable_cet=$libc_cv_compiler_default_cet]) # We keep the original values in `$config_*' and never modify them, so we # can write them unchanged into config.make. Everything else uses -- cgit 1.4.1