From 9f917f7b411c307c34eb1bae85d72ffe26167523 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 3 Dec 2019 21:11:32 +0100 Subject: [PATCH] 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. (cherry picked from commit 9fb8139079ef0bb1aa33a4ae418cbb113b9b9da7) --- NEWS | 1 + configure | 23 ++++++++++++++++++++++- configure.ac | 9 ++++++++- 3 files changed, 31 insertions(+), 2 deletions(-) diff --git a/configure b/configure index fde57d63fe..c02753c0fe 100755 --- a/configure +++ b/configure @@ -3762,11 +3762,32 @@ 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 014e09a5d5..139554b94a 100644 --- a/configure.ac +++ b/configure.ac @@ -464,11 +464,18 @@ 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 -- 2.20.1