From e188b8cd98f599468fbb200c7d590de955daf761 Mon Sep 17 00:00:00 2001 From: Pau Espin Pedrol Date: Mon, 5 Aug 2019 13:46:33 +0200 Subject: configure: Autodetect TLS bug on ARM with old gcc and apply workaround Check if compiler being used contains the bug. GCC 7.3.0 is the oldest version containing the fix, and version 6.3.0 is known to contain the bug. Bug is only known to appear so far only on ARM32. If the bug is present, gcc will generate a wrong binary which wil lend up segfaulting when accessing TLS (__thread) variables under certain conditions. Related: OS#4062 Related: SYS#4628 Change-Id: I8acc2cf41b73da0c3290f1cefd79f2bc68b0e77d --- m4/check_tls_gcc_arm_bug.m4 | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 m4/check_tls_gcc_arm_bug.m4 (limited to 'm4') diff --git a/m4/check_tls_gcc_arm_bug.m4 b/m4/check_tls_gcc_arm_bug.m4 new file mode 100644 index 00000000..73b3e957 --- /dev/null +++ b/m4/check_tls_gcc_arm_bug.m4 @@ -0,0 +1,29 @@ +# OS#4062 (https://osmocom.org/issues/4062) +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81142 +# SYS#4628 + +# Check if We need to apply workaround for TLS bug on ARM platform for GCC < 7.3.0. +# TLS_GCC_ARM_BUG_CFLAGS is filled with required workaround bits if needed. + +AC_DEFUN([CHECK_TLS_GCC_ARM_BUG], [ + TLS_GCC_ARM_BUG_CFLAGS="" + AC_MSG_CHECKING([whether to workaround TLS bug in old gcc on ARM platforms]) + AC_COMPILE_IFELSE([AC_LANG_PROGRAM( + [[ + #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) + /* Check for ARM 32 bit and gcc smaller than 7.3.0 */ + /* We need to explicitly exclude GNUC compatible compilers, since they also define GNUC related tokens */ + #if __arm__ && \ + !defined(__clang__) && !defined(__llvm__) && !defined(__INTEL_COMPILER) && \ + defined(__GNUC__) && GCC_VERSION < 70300 + #error TLS bug present! + #endif + ]])], + [tls_bug_present=no], + [tls_bug_present=yes]) + AS_IF([test "x$tls_bug_present" = "xyes"],[ + TLS_GCC_ARM_BUG_CFLAGS="-mtls-dialect=gnu2" + ]) + AC_SUBST([TLS_GCC_ARM_BUG_CFLAGS]) + AC_MSG_RESULT([$TLS_GCC_ARM_BUG_CFLAGS]) +]) -- cgit v1.2.3